# Developing an AC controller for industrial motors?



## few2many (Jun 23, 2009)

So, when ya gonna tackle building an ac controller that will be programmable for common industrial 220-240, 3 phase motors


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## Qer (May 7, 2008)

*Re: New controller prototype*



few2many said:


> So, when ya gonna tackle building an ac controller that will be programmable for common industrial 220-240, 3 phase motors


Don't hold your breath.


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## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



few2many said:


> So, when ya gonna tackle building an ac controller that will be programmable for common industrial 220-240, 3 phase motors


To use with a common industrial 3ph motor?! You mean like this one frpm Baldor?

http://www.baldor.com/products/detail.asp?1=1&page=8&catalogonly=1&catalog=IDM2334T&product=AC+Motors&family=Inverter+Duty|vw_ACMotors_InverterDuty&winding=09WGX715&rating=40CMB-CONT

Which has a list price of $3352... Sure you can get them used for barely their scrap value, but why would you want to design a complicated product that relies on scrounging for used motors to be economically viable? Oh, and that 20hp motor (which you could reasonably overload, briefly, by 4-5x, weighs 286#).

Now, if there was a commercially available AC motor for EVs _then_ I'd be interested in developing a bad-ass VFD, but there isn't and EVnetics isn't a big enough operation to be developing products without a ready market.


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## JRP3 (Mar 7, 2008)

*Re: New controller prototype*



Tesseract said:


> Now, if there was a commercially available AC motor for EVs _then_ I'd be interested in developing a bad-ass VFD, but there isn't and EVnetics isn't a big enough operation to be developing products without a ready market.


Well HPG has the AC30, AC31, and AC50 motors that are all limited by the Curtis AC 108 volt 550 amp controller. HPG was actively looking for someone to build a higher power controller for their motors as Curtis wasn't interested.


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## AmpEater (Mar 10, 2008)

*Re: New controller prototype*



Tesseract said:


> Sure you can get them used for barely their scrap value, but why would you want to design a complicated product that relies on scrounging for used motors to be economically viable? Oh, and that 20hp motor (which you could reasonably overload, briefly, by 4-5x, weighs 286#).
> 
> Now, if there was a commercially available AC motor for EVs _then_ I'd be interested in developing a bad-ass VFD, but there isn't and EVnetics isn't a big enough operation to be developing products without a ready market.


If you build it, they will come.

Just think....zero competition, you'd own the market

But I do agree we need a commercial source of AC motors suited to conversions at a reasonable price.


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## EVComponents (Apr 20, 2009)

*Re: New controller prototype*



few2many said:


> So, when ya gonna tackle building an ac controller that will be programmable for common industrial 220-240, 3 phase motors


We are looking into it. It will likely be called the Tri-Zilla. Otmar already took a stab at it with one early version.
It will be a project hopefully that has something real to show in 2010.


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## JRP3 (Mar 7, 2008)

*Re: New controller prototype*



AmpEater said:


> But I do agree we need a commercial source of AC motors suited to conversions at a reasonable price.


I think there are some aluminum frame motors from ABB and ABM that might respond well to a higher power controller. These two babies are limited to 84 volts each by the controllers, what a shame


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## CroDriver (Jan 8, 2009)

*Re: New controller prototype*

This one looks good


http://www.diyelectriccar.com/forums/showthread.php?t=32656


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## Bowser330 (Jun 15, 2008)

*Re: New controller prototype*



CroDriver said:


> This one looks good
> 
> 
> http://www.diyelectriccar.com/forums/showthread.php?t=32656


_The ME-400-416 is a 150 KW (200 HP) 400 HZ electric motor designed for heavy duty applications such as electric automobiles.
This unit requires a generator or invertors of 150 Kilowatts of capacity or more to run at full power.

SPECIFICATIONS
200 Horsepower
400 Volts
300 Amps:
12,000 RPM
85 Pounds
http://www.400hertz.net/Products/ME-400-200-416.htm_

NICE!


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## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



CroDriver said:


> This one looks good
> 
> 
> http://www.diyelectriccar.com/forums/showthread.php?t=32656



I sent them an inquiry about this motor. To be honest, it looks like a prototype someone hacked together in their backyard shop, but who knows. As long as it isn't some crap Chinese BLDC motor rebadged as a high frequency AC induction motor I'm willing to test it out.


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## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



JRP3 said:


> I think there are some aluminum frame motors from ABB and ABM that might respond well to a higher power controller. ...


ABM has a limited range of aluminum frame 3ph. induction motors:

http://www.abm-drives.com/2035_three_phase_ac_motors.html


ABB, however, seems to be dumping aluminum for cast iron again  :

http://www.abb.com/product/seitp322/0764c40bf9a5ad0bc1256d8a002a21d3.aspx

Knowing these companies, I suspect both motors are _price-ay, price-ay!_


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## TheSGC (Nov 15, 2007)

*Re: New controller prototype*



Tesseract said:


> Now, if there was a commercially available AC motor for EVs _then_ I'd be interested in developing a bad-ass VFD, but there isn't and EVnetics isn't a big enough operation to be developing products without a ready market.


That does seem to be a very big EV problem. All the production companies say AC is the way too go, but all us DIY'ers get for real choices is DC since very few production companies will even let end users touch these AC motors. And the ones that do sell them in packages. But of course, a bad-ass VFD would still be cool. Maybe a bad-ass VFD needs to be sold with a capable motor.


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## JRP3 (Mar 7, 2008)

*Re: New controller prototype*



TheSGC said:


> Maybe a bad-ass VFD needs to be sold with a capable motor.


That's the thing, what is needed is a somewhat universal AC controller that doesn't have to be paired with a specific motor. It may not be practical to do. Curtis makes them but they are limited to 108 volts and 550 amps.


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## Bowser330 (Jun 15, 2008)

*Re: New controller prototype*



JRP3 said:


> That's the thing, what is needed is a somewhat universal AC controller that doesn't have to be paired with a specific motor. It may not be practical to do. Curtis makes them but they are limited to 108 volts and 550 amps.


Ramp that sucker up to 400V and we can have a party with 550A....


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## few2many (Jun 23, 2009)

*Re: New controller prototype*



Tesseract said:


> To use with a common industrial 3ph motor?! You mean like this one frpm Baldor?
> 
> http://www.baldor.com/products/detail.asp?1=1&page=8&catalogonly=1&catalog=IDM2334T&product=AC+Motors&family=Inverter+Duty|vw_ACMotors_InverterDuty&winding=09WGX715&rating=40CMB-CONT
> 
> ...


 Yes, i got my 30hp baldor free(i know, free is not always the right price)3 phase pim motors can be found for scrap prices, quite a few would be cheaper than forklift motors and how about rebuilding an ac motor vs rebuilding a dc? Throw some sealed bearings in it and run!
And to evcomponents, build it!


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## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



few2many said:


> Yes, i got my 30hp baldor free(i know, free is not always the right price)3 phase pim motors can be found for scrap prices, quite a few would be cheaper than forklift motors and how about rebuilding an ac motor vs rebuilding a dc? Throw some sealed bearings in it and run!
> And to evcomponents, build it!


Yes, indeed, EVComponents - sink your capital into developing an expensive product that when people actually run the numbers a very low percentage will end up buying!

Let's start with your junkpile AC motor, few2many... How much does that 30hp Baldor weigh? I'm guessing somewhere around 400-500 lbs, or about twice the weight with half the peak horsepower (but comparable continuous hp) of the typical DC motor used in EVs. 

Then you would need an honest 100kW Flux Vector Control VFD to use the motor in an EV - V/Hz ain't gonna cut it - which I estimate would cost $7500.

Do the math: a free AC motor plus a $7500 inverter or a $2000 DC motor plus a $2700 Soliton1 (with higher peak output)? I mean, even if the inverter is only $5000 (which would be REALLY tough to manage, unless it was Made In China) the AC combo would still cost more and weigh more.

But hey, the AC myth is a powerful one, and if the folks at 400Hz Engineering quote a reasonable price on their "200hp" motor even I might be persuaded to design a VFD specifically for EVs.


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## EVComponents (Apr 20, 2009)

*Re: New controller prototype*



Tesseract said:


> Yes, indeed, EVComponents - sink your capital into developing an expensive product that when people actually run the numbers a very low percentage will end up buying!


I think you are underestimating the size of the market. There is a lot of demand for this. Of course cost is an issue. But that is the purpose of doing it and producing something that is useful and affordable. Staying still with only DC technology would be a mistake for any company. So once production is running smoothly by the end of the 2009, we will turn our attention to the new AC controller prototype.


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## JRP3 (Mar 7, 2008)

*Re: New controller prototype*



Tesseract said:


> But hey, the AC myth is a powerful one, and if the folks at 400Hz Engineering quote a reasonable price on their "200hp" motor even I might be persuaded to design a VFD specifically for EVs.


There is no myth in a water cooled, brush less, inherently regen capable AC motor, three things that series DC can't do very well. I don't think there is any doubt that the future of mass produced EV's will be AC. People are paying $12-$20k+ for the few available AC systems from Metricmind so I'd think there is some room to under cut that and make a profit if a somewhat universal tunable VFD can be built.


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## Qer (May 7, 2008)

*Re: New controller prototype*



JRP3 said:


> There is no myth in a water cooled, brush less, inherently regen capable AC motor, three things that series DC can't do very well.


Um. Some years ago Renault and Citroen manufactured quite a number of electric cars. Many of them still rolls, most of the ones that don't anymore is because the batteries (flooded NiCd) are more or less impossible to buy (they're available but the environmental fee is absurd because of the cadmium) or the controller unit is broken. The motors are usually still ok.

It's true that they're not water cooled but the brushes doesn't seem to be a big problem and the SepEx-motors can regenerate just fine and with, according to the owners, a quite acceptable motor braking.



JRP3 said:


> I don't think there is any doubt that the future of mass produced EV's will be AC.


No doubt about that, but will it be 3-phase induction AC or something else? And when do we reach "the future" where AC will start to dominate over DC in the DIY-community?

That we're not planning to do an AC-controller now doesn't mean we'll stick to DC forever but right now we will. What happens in a few years, or even in a few months, is impossible to say. It's very probable that we'll start looking into brushless sooner or later, but WHAT kind of brushless is still an open question.



JRP3 said:


> People are paying $12-$20k+ for the few available AC systems from Metricmind so I'd think there is some room to under cut that and make a profit if a somewhat universal tunable VFD can be built.


SOME people are paying those bucks, sure. There's always some people that has enough money to buy The Best without caring about the cost. Some other people are also prepared to pay close to $3000 for a high end DC-controller, but to me it seems that many (maybe a majority of the DIYers?) will still go for the controllers that cost below $2000 and might still go for the second hand old, rusty and with worn out brushes truck motor they found on the scrap heap. Not to mention many still choose lead-acid...


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## JRP3 (Mar 7, 2008)

*Re: New controller prototype*



Qer said:


> Um. Some years ago Renault and Citroen manufactured quite a number of electric cars. Many of them still rolls, most of the ones that don't anymore is because the batteries (flooded NiCd) are more or less impossible to buy (they're available but the environmental fee is absurd because of the cadmium) or the controller unit is broken. The motors are usually still ok.
> 
> It's true that they're not water cooled but the brushes doesn't seem to be a big problem and the SepEx-motors can regenerate just fine and with, according to the owners, a quite acceptable motor braking.


All good points, but brushes are still something of a liability, and getting more power out of a smaller package usually means water cooling, as does having a sealed motor for harsher environments. Obviously Tesla gets plenty of power with air cooling. I'm not saying that series or sepex aren't good enough, just that there are some drawbacks, as with anything. Also, at least here in the states, Sepex in EV appropriate sizes are somewhat rare, and also can't use a generic controller the way series can.




> No doubt about that, but will it be 3-phase induction AC or something else? And when do we reach "the future" where AC will start to dominate over DC in the DIY-community?


Answer, when it becomes cost competitive, no sooner. The series DC trend grew out of the availability of cheap forklift motors and the relative ease of controlling them. As soon as some company starts selling a cost competitive AC system we could easily see AC taking over.


> It's very probable that we'll start looking into brushless sooner or later, but WHAT kind of brushless is still an open question.


AC induction seems to have the advantage of not needing expensive permanent magnets. There may be a growing concern about finding resources for those in the future.
All things being equal, power, price, weight, I think most would choose AC over series DC. Probably at some point even before equality is reached AC would win out. Obviously some people are choosing that route already.


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## Qer (May 7, 2008)

*Re: New controller prototype*



JRP3 said:


> All good points, but brushes are still something of a liability


Ok? Seriously? Brushes being a liability? With a life span equivalent of several oil changes?



JRP3 said:


> Also, at least here in the states, Sepex in EV appropriate sizes are somewhat rare, and also can't use a generic controller the way series can.


Something it does share with 3-phase AC motors, which is why series wound motors are still very popular for DIY because they're simple to use and come in big enough sizes. Take a motor, take a controller, connect, have fun.



JRP3 said:


> All things being equal, power, price, weight, I think most would choose AC over series DC. Probably at some point even before equality is reached AC would win out. Obviously some people are choosing that route already.


Yes, but now you're talking about a distant future again. All things aren't equal and today we don't see a big enough market for going into AC at the moment. Besides, there's other things we'd like to pursue and an AC-controller is quite a bit down on the list.

I do agree that brushed motors will eventually be obsolete technology in vehicles, but so will ICEs and probably also lead acid batteries. Eventually. With a big E if you ask me. Our road map is also pretty well defined already and 3-phase AC isn't a big target on it.


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## CroDriver (Jan 8, 2009)

*Re: New controller prototype*

A new AC vs. DC fight... Let me just make some popcorn


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## Qer (May 7, 2008)

*Re: New controller prototype*



CroDriver said:


> A new AC vs. DC fight... Let me just make some popcorn


Yep, but with a twist. "You should build!", "We don't wanna!"...


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## major (Apr 4, 2008)

*Re: New controller prototype*



Qer said:


> Yep, but with a twist. "You should build!", "We don't wanna!"...


Come on, Qer. All you gotta do is have Tesseract add a third output terminal


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## JRP3 (Mar 7, 2008)

*Re: New controller prototype*



Qer said:


> Ok? Seriously? Brushes being a liability? With a life span equivalent of several oil changes?


 So brushes never break prematurely? Zorching is fun? Reversing an advanced motor isn't problematic? Sure for the most part brushes probably won't be an issue but they are still a mechanical moving part, maybe 8 of them in a motor, which can be a possible failure point.



> I do agree that brushed motors will eventually be obsolete technology in vehicles, but so will ICEs and probably also lead acid batteries. Eventually. With a big E if you ask me. Our road map is also pretty well defined already and 3-phase AC isn't a big target on it.


As far as I'm concerned ICE's and lead acid are already obsolete technology, they just don't know it yet  I do think there is still a lot of life in the series DC motor and if I ever get the itch to build a tire shredding monster I'm sure it will be series DC motor and a Soliton1, or maybe a Sepex and a "Soliton2"  However my personal opinion is that the holy grail of EV's is an affordable universal VFD, (Soliton3 of course), which I realize may not be possible. A cheap and full featured BMS would be nice too, add that to your list.


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## EVComponents (Apr 20, 2009)

*Re: New controller prototype*



> Originally Posted by *CroDriver*
> _A new AC vs. DC fight... Let me just make some popcorn _





Qer said:


> Yep, but with a twist. "You should build!", "We don't wanna!"...


Or "Otmar will figure it out eventually"


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## Dennis (Feb 25, 2008)

*Re: New controller prototype*

It seems that all the major material handling manufactures are using AC drives over DC ones.

http://www.raymondcorp.com/products/index.cfm

http://www.crown.com/usa/products/index2.html

http://www.cat-lift.com/

http://northamerica.yale.com/

http://www.clarkmhc.com/

http://www.nissanforklift.com/products/model/index.htm


DC seems to be dead now since it is now possible to make an AC motor perform like a DC motor that wasn't possible prior to the 80's. DC motors have some uses still, but damn that vector variable frequency drive for AC motors really put DC into the shadows that is for sure! Even trains that were dominated with DC motors are now AC. I also only see DC motors avialable up to 500 HP from industrial motor manufacturers. I think the only manufacture that still makes up to 50,000+ HP DC motors are Teco Westinghouse and GE still makes 1000+ HP DC motors for drilling and traction.


It appears the DIY community is the only one left still stuck with DC motors. AC has been around for a very long time and in use for constant speed apps before any of us where born on this Earth that are in this forum unless we got some really old forum members here, but DC like control of AC motors (torque and speed) has become recent so now we are hearing more about AC this or AC that now.


I'll miss the DC motor when it becomes a museum piece like the ICE.


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## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



Dennis said:


> ...
> DC seems to be dead now since it is now possible to make an AC motor perform like a DC motor that wasn't possible prior to the 80's.


Sigh... and modern surgery plus hormone therapy can turn a guy into a, umm... girl... or something approximately close. Doesn't mean that women are obsolete, now does it?

This debate has been done to death Dennis. Can we all just simply agree that it is easier and cheaper to get a given amount of power from a DC system compared to an AC system? I mean, setting aside the price and availability of the motors for a moment, a 300kW peak power inverter is going to cost way more than the similarly rated Soliton1 or Zilla Z1KHV. 

The last time I tried searching for high power VFDs I think the cheapest I found was $14000 for a ~200hp model. I might be mis-remembering, though.

Anyway, all of this arguing is sort of moot because we will eventually design an EV specific VFD, but first we'd like to make a return on the Soliton1 development effort, and then design some products that are more generally desirable in the EV community (like a truly adaptable smart charger with BMS and "PakTrakR-like" functions).


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## Dennis (Feb 25, 2008)

*Re: New controller prototype*



Tesseract said:


> The last time I tried searching for high power VFDs I think the cheapest I found was $14000 for a ~200hp model. I might be mis-remembering, though.
> 
> Anyway, all of this arguing is sort of moot because we will eventually design an EV specific VFD, but first we'd like to make a return on the Soliton1 development effort, and then design some products that are more generally desirable in the EV community (like a truly adaptable smart charger with BMS and "PakTrakR-like" functions).



Why would you want to market a continuous rated 200 HP VVFD when for EV's they are spending the majority of their time at constant speeds that may require 10~60 HP. I think maybe a thermal limiting controller at 120 horespower rating for 20 seconds at an ambient temp of 40C is more than enough for an EV, with a continuous rating of 70 horespower. I would not concentrate on making a super high performance VVFD because you limit your market reach and the Soliton1 is your cream of the crop that performance minded individuals can purchase for DC setups anyways. Curtis is not high performance and they are the top selling controller for DC EV's. I don't know who the top AC controller seller is though...


You state that you plan to design a VVFD for AC setups, so could you tell us about how many of those Soliton1's you must sell in order to consider a VVFD solution? If the Soliton1 does not meet a profit margin you guys wish to obtain in some time period then do you perhaps have a economy Soliton1 like a 144 volt *Soliton1 Jr*. in the works which is rated 550 amps max like the top selling Curtis to bring about a quick boost in profits so your VVFD design can be started?


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## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



Dennis said:


> Why would you want to market a continuous rated 200 HP VVFD when for EV's they are spending the majority of their time at constant speeds that may require 10~60 HP.


Let's not mix up peak and continuous power and amps... I believe - and personal experience bears this out - that the continuous amp rating is the most important spec for a motor controller, especially when driving in hilly areas or in traffic. I agree that it is not necessary to have 200_hp _continuous, but with commercial, off-the-shelf VFDs you usually need to buy a much higher hp rating to get the desired performance in applications where the motor load varies greatly and often (ie - like in an EV).




Dennis said:


> Curtis is not high performance and they are the top selling controller for DC EV's. I don't know who the top AC controller seller is though...


Not sure where you are going with this... As far as we are concerned the 144V/500A market segment is saturated with choices. Why would any startup want to compete with companies that use Chinese slave labor to keep costs low and/or have thousands of times more capital to throw at product development and manufacturing?

Same thing with AC controllers... there are already "modest" performance controllers and motors out there, so why would we - as a small company without a huge reserve of capital - want to go into a market segment with competitors already there unless we were really sure we could make a similar product for a lot less, or a much better product that people would be willing to pay up for?



Dennis said:


> You state that you plan to design a VVFD for AC setups, so could you tell us about how many of those Soliton1's you must sell in order to consider a VVFD solution?


Sorry, but surely you realize that it would not benefit us in the slightest to let our competitors know either how much it cost to develop the Soliton1, or what our future plans are in any detail.

Finally, whether we develop an EV-specific VFD depends greatly on there being appropriate ac motors available, and I don't mean salvaged/used industrial motors that weigh 20+ pounds per hp. We'd rather not rely on our customers' ability to scrounge parts from a junk yard to be successful, you know.


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## 280z1975 (Oct 2, 2008)

*Re: New controller prototype*



Tesseract said:


> ... snip ... Finally, whether we develop an EV-specific *VFD* ... snip


Just a quick question ... what is VFD? I've been reading here for a while and can't for the life of me think of what it means. A little claification for those who's electric acronym vocab isn't up to par.

-Gregg-


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## major (Apr 4, 2008)

*Re: New controller prototype*



280z1975 said:


> Just a quick question ... what is VFD? I've been reading here for a while and can't for the life of me think of what it means. A little claification for those who's electric acronym vocab isn't up to par.
> 
> -Gregg-


VFD = Variable Frequency Drive. For AC motor controllers, one must control the frequency (as well as the voltage) to control the speed (and torque) of the motor.

Sometimes called Freq Drives.

Regards,

major


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## few2many (Jun 23, 2009)

*Re: New controller prototype*

Oh, great idea?
How about using the soliton 1 as a base, then having a 3 phase inverter box as an option for it to mount to? Use the soliton as an insane power section(more than ac would need), that would then feed into a box that would handle the inversion, then to the motor. This box would also handle regen when the motor output was higher then the controllers output. Hopefully without blowing up the controller and letting the magic smoke out.


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## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



few2many said:


> Oh, great idea?...


Possible, but not nearly as cost-effective as simply making an inverter because the switches in the inverter can perform both conversion and inversion simultaneously. Also, there's the problem of coordinating the two functional blocks, especially synchronizing the gate drive over more than the usual distances required.

On a completely separate note, does anyone want to take a stab at how big the demand would be for an EV-specific inverter with the same power output as the Soliton1 (~300kW), assuming the usual rule that an inverter costs 2.5x more per kW than a dc converter? 

My guess is around 20 units per year.


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## major (Apr 4, 2008)

*Re: New controller prototype*



Tesseract said:


> On a completely separate note, does anyone want to take a stab at how big the demand would be for an EV-specific inverter with the same power output as the Soliton1 (~300kW), assuming the usual rule that an inverter costs 2.5x more per kW than a dc converter?
> 
> My guess is around 20 units per year.


Hi Tesser,

You're optimistic. 300kW is basically double anything which has been available in 230 VAC class VFDs, mobile or industrial. I suspect the 2.5x more would end up being at least 10x. And there are no AC motors to fit the bill, now or under development of which I'm aware.

My guess is that if you had an inverter/motor combo package for 300kW which would run from a 350 V battery, it'd cost so much you'd sell one if you're lucky.

Now for 300kW AC drives, one could use a pair of 150s. Then you have an expanded market. Those that want "reasonable" power buy a single and those that want crazy power buy the pair. Market price for the 150kW package seems to be $20 to $30,000. My impression is that market demand for that product is less than 100/yr, maybe like a dozen a few years ago. This of course excluding BMW buying ACPs and Tesla.

And, I think you have alluded to the fact, what sense is such a VFD when there is no suitable motor available for a reasonable price?

I may kid you about putting the third output terminal on your product, but I really wonder the sense of developing an AC product without a matched motor.

My 2kW worth,

major


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## major (Apr 4, 2008)

*Re: New controller prototype*



Tesseract said:


> Possible, but not nearly as cost-effective as simply making an inverter because the switches in the inverter can perform both conversion and inversion simultaneously.


Hi Tesser,

I agree with you, but there is this outfit that doesn't. http://www.ecycle.com/motorgenerator.html 

From that web page.



> *Electronic Commutator*
> *Integrated electronics are mounted on the rear cover and cooled with a brushless fan. This enables the SolidSlot brushless motor to be run directly from a battery or with an industry standard DC motor controller. *
> *For increased flexibility, the electronic commutator can be mounted remotely and cooled by air or liquid. *​




And this http://www.ecycle.com/buckboost.html which is the voltage controller to go in front of their electronic commutator.​ 
Sounds like a silly approach to me ​ 
major​


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## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



major said:


> You're optimistic. 300kW is basically double anything which has been available in 230 VAC class VFDs, mobile or industrial. I suspect the 2.5x more would end up being at least 10x. And there are no AC motors to fit the bill, now or under development of which I'm aware.


Rarely am I accused of being _opti_mistic - makes for a refreshing change from my usual status as the Black Cloud of Doom (tm).


Of course, you are echoing every one my previous stated arguments against developing an EV-specific VFD. 

That said, if the inverter had a more realistic power output - say, 150 to 200kw - it could be done with currently available "6-pack" IGBT modules. The control and drive circuits are a lot more complex, of course, but there are also chipsets tailored to VFD use by several manufacturers.

But, wasn't esteemed -  - fellow member Technologic going to build a big, bad VFD for less than $400 in parts? Wonder what ever happened to him and that revolutionary project? Must be in China lining up some really good deals on IGBTs and enclosure castings...


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## JRP3 (Mar 7, 2008)

Maybe it's not possible without Chinese manufacturing but I think there is a market for an affordable VFD somewhere between the 108 volt 550 amp Curtis, http://curtisinst.com/index.cfm?fuseaction=cDatasheets.dspListDS&CatID=1
which probably runs around $2000-$2500, and an ACP type unit which might cost $8000-$9000 if purchased on it's own. (I get that estimate from the fact that ACP can sell their motor/controller package for around $11k in volume.) Just doubling the voltage of the Curtis unit would make it a much more EV capable product.
MES-DEA can sell their TIM600 100kw inverter through a dealer for $6,300
http://metricmind.com/prices.htm
http://metricmind.com/inverter.htm
Is a motor specific inverter that much cheaper to build than a universal one?


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## JRP3 (Mar 7, 2008)

Though I understand not wanting to develop a VFD for motors that don't exist an affordable VFD could drive the manufacturing of the motors since it's not that expensive to build the motors. Currently HPG motors are crippled by the Curtis but I doubt there is any reason they couldn't build higher voltage motors for the same cost, if they had a cost effective way to control them.


----------



## Batterypoweredtoad (Feb 5, 2008)

JRP3 said:


> Though I understand not wanting to develop a VFD for motors that don't exist an affordable VFD could drive the manufacturing of the motors since it's not that expensive to build the motors. Currently HPG motors are crippled by the Curtis but I doubt there is any reason they couldn't build higher voltage motors for the same cost, if they had a cost effective way to control them.


Looking at the RPM capability and the torque curve falling off less than a 1/4 of the way into that RPM range, I'm guessing they could handle twice the voltage already.


----------



## major (Apr 4, 2008)

JRP3 said:


> Is a motor specific inverter that much cheaper to build than a universal one?


Probably not. But it would likely be a whole lot less to develop. And have a whole lot less application engineering support required.

I've not used the Curtis AC unit. I don't know how they tune to the specific motor in use. But this is something larger industrial drives do commonly. It is not an issue for V/f, but in vector mode, it is a must. And you are always running to the unknown weird motor or application which just won't behave with the drive.

It looks easy after it is done right. But the devil is in the details, and there are a million details in AC.

major


----------



## few2many (Jun 23, 2009)

*Re: New controller prototype*



Tesseract said:


> Yes, indeed, EVComponents - sink your capital into developing an expensive product that when people actually run the numbers a very low percentage will end up buying!
> 
> Let's start with your junkpile AC motor, few2many... How much does that 30hp Baldor weigh? I'm guessing somewhere around 400-500 lbs, or about twice the weight with half the peak horsepower (but comparable continuous hp) of the typical DC motor used in EVs.
> 
> ...


285lbs little buddy! and i would pay 5,000usd for an ev specific controller. I'm having surprisingly good luck finding industrial inverters that will run on dc bus(as slaves, thats MY slave)man I'm finding inveters from 5-120hp and 1,000-45,000usd
Man, im liking this kilt lifter, only from local fourpeaks brewing baby!


----------



## JRP3 (Mar 7, 2008)

*Re: New controller prototype*



few2many said:


> Man, im liking this kilt lifter, only from local fourpeaks brewing baby!


Few2many indeed


----------



## samborambo (Aug 27, 2008)

*Re: New controller prototype*



Tesseract said:


> Yes, indeed, EVComponents - sink your capital into developing an expensive product that when people actually run the numbers a very low percentage will end up buying!
> 
> Let's start with your junkpile AC motor, few2many... How much does that 30hp Baldor weigh? I'm guessing somewhere around 400-500 lbs, or about twice the weight with half the peak horsepower (but comparable continuous hp) of the typical DC motor used in EVs.
> 
> ...


I see Tesseract has become quite the AC pessimist since his Solution 1 hit the market. T, the AC debate is not as simple as you try to make it.

An "honest" high voltage 100kW is under US$1000 in parts - even in prototype quantities from mauser.com. What's the difference in cost between a V/Hz controller and a flux vector drive? I'll tell you. Software and a few more MIPS.

ABB is not switching to cast iron. Quite the opposite. Their new line of industrial performance motors are all aluminium. I've priced their 11kW continuous, 37.5kW (50hp) peak, 115lb motors at around US$1500 (was priced in NZ dollars) imported from overseas through ABB NZ.

So, why doesn't someone "just make an AC controller"? We are. The Tumanako Project is an open source effort covering all EV subsystems - AC motor controller, BMS, charger, HMI, etc. My contribution is a dsPIC based motor controller that can be tuned on the fly to a specific motor aimed at DIY conversions. My involvement in the project is to ensure my controller design remains compatible with the other subsystems.

Everyone wins with an open source project like this. If some (chinese, maybe) manufacturer picks up the design and manufactures these controllers for less than two grand US, we all benefit. 

Assuming that an ABB 94hp peak, 210lb AC motor is priced relative to the 50hp one, the 94hp motor and 100kW controller would be under US$5000. 

Sam.


----------



## major (Apr 4, 2008)

*Re: New controller prototype*



samborambo said:


> the 94hp motor and 100kW controller would be under US$5000.


Cool  When will that be available?


----------



## samborambo (Aug 27, 2008)

*Re: New controller prototype*



major said:


> Cool  When will that be available?


At this stage I don't have plans to produce my controller commercially. However, the source code, schematics, board files and drawings will be available soon. I'm basing the firmware on the Microchip source code for their application note but eventually rewriting Microchip's source from scratch in order for the source to be licensed as LGPL3. I'm talking to Microchip about how comfortable they are with me publishing their source to a CVS repository at the moment and will have an answer this week sometime, hopefully. 

There was a submission to Circuit Cellar last year for a 100kW dsPIC ACIM field orientated control EV VFD with an open loop tuning system done in Labview. They based their firmware on the same application note source code that I'm using. It serves as an excellent proof of concept of what can be done with the dsPIC. I want to integrate the tuning system into the firmware and make it closed loop for extremely simple controller configuration.

The other members of Tumanako are focusing on getting CAN bus communication between subsystems. I want to make sure there's still a discrete I/O option for every function which is probably more attractive for DIYers doing a retrofit on an older car. Programming the controller with different set points, parameter up/download, firmware upgrade or diagnostics can be done over a standard RS-232 VT-100 terminal.

Anyone with access to a small to medium sized CNC mill and skilled at soldering and electronic testing will be able to build the controller themselves.

Sam.


----------



## 280z1975 (Oct 2, 2008)

*Re: New controller prototype*



major said:


> Cool  When will that be available?


I think major was more referring to the ABB motor ... any links to the motor (a quick google didn't result in anything about it)

-Gregg-


----------



## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



samborambo said:


> I see Tesseract has become quite the AC pessimist since his Solution 1 hit the market. T, the AC debate is not as simple as you try to make it.


I'll take this is in the spirit of a collegial debate although we are both known to be testy at times... 

Nah - I've actually never thought using AC induction motors in traction applications made much sense. I am not opposed to ALL electrically commutated motors, though. For example, I think the _switched reluctance motor_ has some real merit: much higher peak torque than an equivalent size ACIM, much simpler rotor construction (higher RPM tolerance, too), simpler inverter design. See, for example, Freescale's page on them:

http://www.freescale.com/webapp/sps/site/overview.jsp?code=DRMTRSWTRLCTMTR




samborambo said:


> An "honest" high voltage 100kW is under US$1000 in parts - even in prototype quantities from mauser.com. What's the difference in cost between a V/Hz controller and a flux vector drive? I'll tell you. Software and a few more MIPS.


Of course there is no difference in the basic hardware required between the two control schemes - in fact, I don't believe I ever stated otherwise - but you should know better than most here that there is more to the cost of a product than just the parts that go into it. There's no question an open source controller can be built by a skilled DIY'er for $1000, but that's not really relevant to me because that market is necessarily limited to people who:

1. want to convert their vehicle to electric
2. can do the work themselves
3. are adamant about going with AC over DC
4. and have all of the equipment to build there own controller, if not actually design it.

That's a helluva small market.

But FWIW, just the 3-phase IGBT modules I've been looking at for a 100-150kW inverter cost $500-$700 so I don't think your $1000 price target is realistic. You really need to go through and tally up every part - bus bars (or plates), hardware, enclosure, etc... - to get an accurate sum; anything else will paint a deceptively optimistic picture.




samborambo said:


> ABB is not switching to cast iron. Quite the opposite. Their new line of industrial performance motors are all aluminium. I've priced their 11kW continuous, 37.5kW (50hp) peak, 115lb motors at around US$1500 (was priced in NZ dollars) imported from overseas through ABB NZ.


I was just going by what I found on their website when I did a google search on _aluminum frame motors ABB_:

_"ABB's Process performance *aluminum* *motors* are going to be replaced with the corresponding cast iron *motors*. Please check always the availability with your nearest *ABB* sales office."_

That said, I am not too impressed by a motor with a nominal output of 11kW, a peak output of 37.5kw and a price tag of $1500US.




samborambo said:


> Everyone wins with an open source project like this. If some (chinese, maybe) manufacturer picks up the design and manufactures these controllers for less than two grand US, we all benefit.


I strongly disagree with this point of view, though I recognize the arguments for it. I'm not going to go off on some political rant but I will say that my main objection here is that China can price things so cheaply because it uses what amounts to slave labor. A country that outsources all of its manufacturing soon finds it can't manufacturer even the simplest products and then it is in just as bad a predicament as comes about from having to import all of its energy.


----------



## samborambo (Aug 27, 2008)

*Re: New controller prototype*



280z1975 said:


> I think major was more referring to the ABB motor ... any links to the motor (a quick google didn't result in anything about it)
> 
> -Gregg-


Look on the AC Motor Selection wiki page. I added a bunch of ABB motors and links to their datasheet.

Sam.


----------



## samborambo (Aug 27, 2008)

*Re: New controller prototype*



Tesseract said:


> I'll take this is in the spirit of a collegial debate although we are both known to be testy at times...
> 
> Nah - I've actually never thought using AC induction motors in traction applications made much sense. I am not opposed to ALL electrically commutated motors, though. For example, I think the _switched reluctance motor_ has some real merit: much higher peak torque than an equivalent size ACIM, much simpler rotor construction (higher RPM tolerance, too), simpler inverter design. See, for example, Freescale's page on them:
> 
> ...


Fine then, don't make them in China. I agree that the working conditions and environment ethics of the Chinese is questionable at best. I was using Chinese manufacturing to make my point about how cheaply the inverter could be built/sold for. If I commissioned someone here in NZ to make these, it would add at most $200 to the price tag. No biggy. 

Tesseract, I don't want to get into another AC vs DC debate. It's like flogging a dead horse. There are many valid reasons for people wanting to go with AC.

Interesting that you mention SR motors. You ever seen one in action? They sound like 2-stroke chainsaws thanks to the very high torque ripple inherent in SR design.

The ABB motors you're looking for are the Industrial Performance range, not the Process Performance. I think ABB are standardising on cast iron for process and aluminium for industrial.

You can find no-name brand aluminium induction motors in the same power rating for much, much less - well under US$1000 for an 11kW. The main reasons why I'm going with ABB are full datasheets are available, the motors appear smaller for a given size (132M frame instead of 160L), and a ridiculous discount on the motors since the company I work for has a strong business relationship with them.


----------



## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



samborambo said:


> ...
> Interesting that you mention SR motors. You ever seen one in action? They sound like 2-stroke chainsaws thanks to the very high torque ripple inherent in SR design.


Nope, I haven't. But I did only say they look promising, not that they are the end-all, be-all of motors. I imagine adding a few more poles would help quiet them down. Were the motors you observed 6/4 SRMs?




samborambo said:


> The ABB motors you're looking for are the Industrial Performance range, not the Process Performance. I think ABB are standardising on cast iron for process and aluminium for industrial.


Thanks for the tip on that - I'll check those out.


----------



## Morf (May 29, 2009)

Hello,
This made my day today. Here is a guy who also wanted a 3 phase in his ev. Rudolph is from Sarajevo, you can find him at: evalbum.com/1080. If you want to see more of his work, take a look at: Elektroauto-Opel Kadette ``Bev 1.... on You Tube. 
For myself, I had been trying to work a Danfoss Variable Drive into the equation for my project e utility van. Rudolph beat me to it with his front fenderless Opel. Look at that big decal on his hood.

My motor came in on a palate last week. This is a 16.3 Oswald 3 phase PM Synchronous, and it was built in 2003. The drive shaft is 60 mm in diameter, a hint I hope that all the advertised torque is there. She is rated for 470 Nm, and my favorite part, 470 nm at stall, and 850 Nm max. The other stats are 360 volts, 92 amps, max 170 amps, and it came with an industrial notched drive on it, gone now, that would make half of a barbell. She weighs 244kg and is water cooled.

So I have been looking at industrial salvage and other sites in consideration of a drive. The rapid pace of technology takes the fun out of looking at yesteryears stuff, however there are older Allen Bradleys around if one is to give up on having vector technology. 

However the Danfoss guy has been most helpful, and his products get good grades from the people who have worked with his drives in the past. And he has me considering a FC-302 Danfoss after he reviewed the needs of the Oswald, and that is the same number as Rudolph used on his first ev. However it is the last bunch of numbers after the 302 that tell the story so looking under the hood of the Opel doesn`t tell one as much as a guy might think.

Mitsubishi`s ads for their modular drives sounded very interesting-add parts to your system as you can pay for them, if I understood it right. They claimed energy loss at a new low level, but I didn`t look at the date on the page. 

My next hunt is for some aluminum frame rails to use as a base to set stuff on. 

One of the serious warnings I have heard and respect is to pay much attention to being sure the sine waves are clean and proper. I also think it is worthwhile to be concerned about vibration and shock to equipment that in some cases was never intended to be bounced about. Shielding is an issue. 

And going back to the beginning, take a look at that first address: evalbums for another 3 phase installation in a Suzuki 4 wheel drive where a fellow is running a torkey motor directly into his transfer case with satisfactory results. Cheers,


----------



## Morf (May 29, 2009)

Hello,
Here are some of the papers on the net that have been informative in my quest for a motor drive. ``Development of a Three-Phase Three Level Inverter for an Electric Vehicle. It deals with switching devices selection and inverter construction in 3 phase motor usage. The paper describes laminated copper busbars, and other practical details such as the ratio of switching devices capacity as at lest 1.5 times the value of the steady state current, and explains why. They also discuss clamping diode selection and how they should be chosen. Best of all they name and number the products they are using, in this case Siemens IGBTs, and give reasons for some of their choices that are familiar (`because they are the cheapest`).

Mounting of the diodes, etc. on a large heat sink is also covered, with a discussion of proper proceedure to make sure of thermal contact. The paper then continues with graphs showing the author`s (Canterbury U. of New Zealand) test results. 

Fairchild`s introduction of FGA20N120FTD model Trench IGBT has, according to a paper, a 25 % less conduction power loss and 8% less switching losses, which reduces the operating temperature considerably. The writeup on this product is at: www2.electronicproducts.com/High-performance_energy-efficicient_Igbts-article-t. More information is on http://semiconductors.global spec.com/LearnMore/Semiconductors/Discrete/Transistors/I...

To lean about the Darlington Pair, where it tells about how to make up your own set that can be turned on by a tiny base current but has a very high current gain, ``such as 10,000``. This was on http://www.kpsec.freeuk.com/trancirc.htm and it lead to:

A Complete Implementation of Vector Control for a Four-Switch Three Phase Inverter Fed IM Drive.... `Instead of a usual 6-switch three -phase inverter(SSTPI) a 4-switch three-phase inverter (FSTPI) is used`. `A cost effective FSTPI fed IM drive using Field-Oriented-Control and Space-Vector PWM controller (with new control SVPWM approach) is implemented in real time`. `This reduces the price of the inverter, the switching losses, and the complication of the control board for generating 6 PWM logic signals`. The author includes a discussion about the complications that he mentions concerning the feeds for a 6 switch system, and a remedy. 

A paper on pulse patterns called ``Improvement of Pulse Pattern for Spece Vector Modulated Matrix Converters`` is a discussion of a ``novel modulation``. Dealing with PWM generation, I am doing my best to absorb this page, and include it only because I think that there is new technology here that is included in late Yaskawa motor drivers that provide the remarkable flexability of use they have. I know a bit about harmonics and sine wave shapes, but not nearly enough. And now to put some of the above onto a shop table and see if I can make something work. Please comment on the `reduction of switches` model and the benefits claimed that go beyond cost. I will be begging for input on building a motor drive if I can`t afford my beloved Danfoss. Cheers.


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## samborambo (Aug 27, 2008)

Morf said:


> My motor came in on a palate last week. This is a 16.3 Oswald 3 phase PM Synchronous, and it was built in 2003. The drive shaft is 60 mm in diameter, a hint I hope that all the advertised torque is there. She is rated for 470 Nm, and my favorite part, 470 nm at stall, and 850 Nm max. The other stats are 360 volts, 92 amps, max 170 amps, and it came with an industrial notched drive on it, gone now, that would make half of a barbell. She weighs 244kg and is water cooled.


From the specs you've given, the motor appears to have a base speed of 600RPM. Is that correct? Is it a 10 pole / 50Hz motor? I conclude from the derived base speed that the motor would be good for around 53kW. Since you can't field weaken a PM motor, you're limited to not much above the base speed as the BEMF voltage increases with speed. Torque will drop off sharply past 600RPM if you don't have the means to run the motor at higher than 360VAC.


> One of the serious warnings I have heard and respect is to pay much attention to being sure the sine waves are clean and proper. I also think it is worthwhile to be concerned about vibration and shock to equipment that in some cases was never intended to be bounced about. Shielding is an issue.


I don't know which sales rep told you this but it's marketing hype/lies. A field orientated control drive doesn't necessarily produce sine wave output. It outputs voltage derived from what the motor needs which is based on the BEMF profile of the motor. Every motor, especially PMSM, has a different BEMF profile and it's not necessarily sinusoidal. Harmonics are not usually an issue these days with modern vector drives. Shielding can be a problem in an industrial environment with long runs of cables but you shouldn't be running more than a metre of cable between the controller and the motor anyway so it's not really an issue.

Sam.


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## Morf (May 29, 2009)

Hello Samborambo,
Thanks for your reply about an MF 16.3 Oswald Sync. PM. Here is the information source on the motor: Put ``oswald motor germany`` in your search engine. Take the available page on TF torque engines, after you get there go to the upper left hand column and take the second item down, which is the MF series. There are three downloads (fast) that will become available. These specs. are for the same motor I have but are somewhat higher, which is mentioned in one of the footnotes. Going to crawl off to bed now. All of this type motor listed in the new literature are 6 pole.


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## Morf (May 29, 2009)

Samborambo Again, Hi,
Please let me know if my 2:00 AM attempt to get a bundle of information to you was too messy to be useful. I am most interested in your observation about the Oswald motor. Oswald`s information bulletins mention that the current motors have higher number stats than the older same model. I figured that going by the new higher numbers would give me some headroom in case I were to do a rewind according to factory specs and eventually come out with the higher specs on my motor. Other than that it is the same motor as found in the new specs. 
If I read the literature right, it seems to me I am looking at 1000 sweet spot rpm at least, and I wasn`t concerned about more than that for my purposes, so I didn`t try to do the calculations. Everything would be better if I knew what f, followed by an even smaller letter n meant. That is followed by 1000 rpm on the motor tag. Your observations would be greatly appreciated. Cheers.


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## samborambo (Aug 27, 2008)

Those motors look excellent - especially the 3000RPM version having a very high power to weight ratio. AC induction motors develop peak power at their base speed/frequency. You would be wise to keep the motor in the constant power area if you're using a manual gearbox. If you're going fixed drive with a reduction ratio, you want to make full use of the constant power region and minimize the constant torque area at low RPM and avoid the torque tail off region at high RPM.

Take the time to learn mechanical torque and force equations to choose and set up the motor correctly. There's some good information on the wiki pages of this site.

I'd be interested to know how much you're quoted for these motors.

Sam.


----------



## yarross (Jan 7, 2009)

*Re: New controller prototype*



Qer said:


> It's true that they're not water cooled but the brushes doesn't seem to be a big problem and the SepEx-motors can regenerate just fine and with, according to the owners, a quite acceptable motor braking.


A SepEx controller providing all those features that an inverter does needs five switches - ony one less than inverter. It will not be much less expensive. AC motors are simpler, more rugged and cheaper (for given power).
High computational power requirements are not an obstacle today. Computational power is cheap. The key is the cost of power modules. Other components such a speed/current sensors or DC bus caps are required for both types.
Tri-Zillas are really welcome.


----------



## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



yarross said:


> A SepEx controller providing all those features that an inverter does needs five switches - ony one less than inverter. It will not be much less expensive.


This is a just a tad inaccurate, dontcha think, since the 4 switches in the field H-bridge need to handle much less current and are therefore much less expensive. 



yarross said:


> AC motors are simpler, more rugged and cheaper (for given power).


Yeah, yeah... and they can cure cancer, bring about world peace and eradicate hunger, too...


----------



## yarross (Jan 7, 2009)

*Re: New controller prototype*



Tesseract said:


> This is a just a tad inaccurate, dontcha think, since the 4 switches in the field H-bridge need to handle much less current and are therefore much less expensive.


This arrangement does not provide regeneration up to standstill. Using only one switch in stepdown mode for the armature will not allow step-up operation. You can't compensate for this by forcing max current of the field winding - you will quickly hit the limit where BEMF falls below DC bus voltage and regeneration is over. So, such drive is inferior when compared to AC drive.
You must use H bridge in the armature circuit to achieve the same functionality that AC drives have.
Or you can design the motor so it normally would operate in deep field weakening and have wide margin for low RPM regeration, but this means such motor is unnecessary bulky, heavy, costly and makes poor usage of active materials.



Tesseract said:


> Yeah, yeah... and they can cure cancer, bring about world peace and eradicate hunger, too...


So there're even more reasons to make a transition


----------



## Tesseract (Sep 27, 2008)

*Re: New controller prototype*



yarross said:


> This arrangement does not provide regeneration up to standstill.


No motor provides regeneration all the way down to 0 rpm.




yarross said:


> Using only one switch in stepdown mode for the armature will not allow step-up operation.


Correct, but I wasn't commenting on the ideal hardware arrangement, only on the one you implied when you said that a SepEx controller only requires 1 less switch than a 3ph. AC inverter.




yarross said:


> ..You must use H bridge in the armature circuit to achieve the same functionality that AC drives have.


No, you only need a half-bridge to operate in boost mode. There is no advantage to switching the polarity of both the field and armature circuits.


----------



## yarross (Jan 7, 2009)

*Re: New controller prototype*



Tesseract said:


> Correct, but I wasn't commenting on the ideal hardware arrangement, only on the one you implied when you said that a SepEx controller only requires 1 less switch than a 3ph. AC inverter.
> No, you only need a half-bridge to operate in boost mode. There is no advantage to switching the polarity of both the field and armature circuits.


If you insist on placing H bridge in the field, yes there's no reason to put another one into armature circuit.
But now you have six switches and two of them have to be sized for full amperage, and inverter switches may be smaller. Add the cost of heavier, more complicated motor that does not have the capability to operate in the 6k-10kRPM range required to achieve good power/weight ratio.
So, assuming same production scales, I doubt that today the SepEx drive will be cheaper. It was superior in early 90s, but now technology advanced. There's a reason that all planned high-volume production cars use either IMs or (mostly) PMSMs.


----------



## major (Apr 4, 2008)

*Re: New controller prototype*

Hi yarr and Tess,



yarross said:


> There's a reason that all planned high-volume production cars use either IMs or (mostly) PMSMs.


Yeah, probably more than one reason, but it is not that a 3 phase inverter is less costly than a SepEx controller. Curtis makes both types in similar voltage and power. Compare those prices.



yarross said:


> This arrangement does not provide regeneration up to standstill.





Tesseract said:


> No motor provides regeneration all the way down to 0 rpm.


Hey Tess,

Going downhill they could 

And yarr,

Both a good SepEx and AC system can bring the vehicle to a complete stop with "electric" braking. That would be regeneration down to the point where it takes more energy to cover losses than available from the kinetic source, and then producing reverse torque with power from the battery.

I have experience with both ACIM and SepEx drives. On equal vehicles with well tuned systems, you could not tell the difference between AC and SepEx from the driver's seat.



yarross said:


> and inverter switches may be smaller.


I'm not so sure about that. If smaller, not by much.



yarross said:


> Add the cost of heavier, more complicated motor that does not have the capability to operate in the 6k-10kRPM range required to achieve good power/weight ratio.


Then add the cost of the extra gear reduction and associated losses to the AC system.

Again, just part of the AC/DC puzzle. In the end, AC will win for production EVs, no doubt in my mind. But for now, where does the DIYer go? Unless he has a father in the AC drive business, his value choice looks like DC.

Regards,

major


----------



## Anonymous Expert (Oct 25, 2009)

I am interested in hearing what people would be willing to pay for an ac inverter and what the requirements for said inverter would be. I might be willing to put something together if it would be profitable.


----------



## JRP3 (Mar 7, 2008)

I already have the Curtis 108 volt 550 amp for my HPG motor, the whole package was $4200, but now can be found for just under $4k. Assuming the Curtis was a bit more than half of that, maybe $2200, increasing the voltage to around 200 and upping the amperage a bit would be worth another $1-1.5K I think. From what I've seen that's probably not profitable unless you're building over seas in volume. MES-DEA has their TIM 400 100kw max drive for $6K
http://metricmind.com/prices.htm


----------



## yarross (Jan 7, 2009)

*Re: New controller prototype*



major said:


> Hi yarr and Tess,


 Hi.



major said:


> Yeah, probably more than one reason, but it is not that a 3 phase inverter is less costly than a SepEx controller. Curtis makes both types in similar voltage and power. Compare those prices.


 I didn't say that an inverter will be cheaper. I say a SepEx controller won't be much cheaper and that difference will be offset (at least to some extent) by cheaper motor.



major said:


> Both a good SepEx and AC system can bring the vehicle to a complete stop with "electric" braking. That would be regeneration down to the point where it takes more energy to cover losses than available from the kinetic source, and then producing reverse torque with power from the battery.


That's the point. Question is how low RPM the drive can go before switching to that (plugging) mode. Valentine states that an AC drive can do regeneration well up to standstill.



major said:


> I have experience with both ACIM and SepEx drives. On equal vehicles with well tuned systems, you could not tell the difference between AC and SepEx from the driver's seat.


 Should not be suprising. All that hocus-pocus with vector controll is to turn an AC motor into virtual SepEx to obtain a drive with good controll without inherent SepEx motor drawbacks.



major said:


> Then add the cost of the extra gear reduction and associated losses to the AC system.


You need a gearbox with SepEx drive anyway. I've found numbers that a high speed motor+gearbox is sligthly more efficient than a low speed direct drive, even counting gearbox losses.


----------



## major (Apr 4, 2008)

*Re: New controller prototype*



yarross said:


> I've found numbers that a high speed motor+gearbox is sligthly more efficient than a low speed direct drive, even counting gearbox losses.


Hi yarr,

Can you give me a source for your findings? I've been in an ongoing discussion with someone on the subject and loss estimates range form 1% to 6% for an extra gear mesh, spur or planetary. And that is a pretty big range.

Thanks,

major


----------



## yarross (Jan 7, 2009)

*Re: New controller prototype*



major said:


> Can you give me a source for your findings? I've been in an ongoing discussion with someone on the subject and loss estimates range form 1% to 6% for an extra gear mesh, spur or planetary. And that is a pretty big range.


Typical losses per planetary stage is 3% (http://planetarygearbox.net, I think low viscosity fluids (3% is for solid grease I think) and relaxed clearance requirements will somewhat decrease this number, let's say 1.5%).
Now compare industrial motors, 2p with 8p (direct drive would require a motor in 16p range, but I can't find industrial 16p motor);
2p 11kW: http://www.tamel.pl/typ.php?typ=w_aluminium&grupa=17&silnik=13&lang=en (ne=91%, m=100kg, pf=0.89)
8p 11kW: http://www.tamel.pl/typ.php?typ=w_aluminium&grupa=17&silnik=65&lang=en (ne=90%, m=140kg, pf=0.67)
So, 2p motor + gearbox will yield ne=89.635%, now count increased inverter losses due to lower pf and rolling resistance losses due to extra weight, and keep in mind that 16p motor will have lower ne, lower pf and more weight.
And those numbers are for 3000rpm/50Hz motor. 6000rpm motor is more likely to be used in traction drive and will have somewhat improved characteristics, especially weight (may reach 1kW/kg for 50kW drive).
More comparison can be found in "Lightweight electric /hybrid vehicles design".


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## Morf (May 29, 2009)

Samborambo and others, Hi,
In keeping watch on the motor drives as they show up on ebay and ebay stores, I passed on a 350 hp Fuji-GE AF-300 P11. It had overkill amps at 415, my required max amps is at least 170, maybe 215 if my motor had an upgrade to the later specs sometime. But the rest of the features are, for certain, overkill for my purposes. I don`t expect to need communication with a whole assembly line through my motor drive. Maybe I could drive through town and start all the coffee makers en mass. 

Next was an overview of all the new replacement boards available for drives. I spent a day trying to figre out what I would get for a 1500. dollar (asking) GE control board for a P11, perhaps to build around it. GE has seminar grade information on their sites, but it isn`t enough, my fault likely.

A modular system seemed like a good idea early on. But looking for no frills leaves a e builder with few choices until (maybe) this site. Associated Power Systems, Inc. in Hicksville, NY advertises a medium and high power DC to AC 3 phase converter. In addition they have heatsinks that look like Rorschalk tests, water cooled clamp systems that assure your thermal bond with silicon semiconductors >23mm. , and cool both sides. They have inverters and converters, and IGBT drive boards. And when you call, you get an engineer to talk to. I know nothing about their pricing at this time, but bathing in the glory of the availability of what I can finally find is `priceless`(well, almost). 

Planning for my talk to them tomorrow, I see they also offer dc to dc, variable, IGBTs, reverse, and regenerative braking. The focus item will be their advertised IAP100B120 SIXPAC dc to ac. I mean to ask them about trench IGBTs, and provisions for a medium soft start. They also have water cooled as a full line option. That feature should go well with the motor which is also liquid cooled. This company`s menu of products also looks promising for those planning for wind generators and solar array collection. I hope this is a good lead. 

And Sam, I never got to that part of motor cost from Europe considering duties, and import tax, shipping and handling. Mr. Bachmann will quote you if you are interested in a new one. If so, good for you. Cheers


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## JRP3 (Mar 7, 2008)

Was that supposed to be Applied Power Systems?
http://www.appliedps.com/


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## Morf (May 29, 2009)

Hi JRP3,
Thank you for correcting the error I made in calling Applied Power Systems of Hicksville, NY by another name. Much appreciated.


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## Morf (May 29, 2009)

Dear DC to 3 phase AC Inverter Fans, 

This is an update on my communications with Applied Power Systems, after I emailed them with my general early ideas for powering my PM Oswald Synchronous 3 phase Motor in a lite utility van.

Following up with a phone call, I learned that APS`s custom build components are derived from base units that APS has a history with. 
Their components are updated and friendly to different environments. Engineer Les Doti sent me papers on their 150 kW 3 phase inverter, liquid cooled. He says it will easily get me the output of 170 amps, even when switching at 10kHz. He then explained the benefits of this model over the next size smaller one, specifically pointing out that the smaller one would run hotter. 

Mr. Doti passed on information to me about missteps that are possible in the building of, or purchase of, an inverter. The word gratitude comes to mind. I have noticed that many companies regard their pricing as confidential, and for custom builds that issue gets particularly shakey. I will ask APS about their policy. In checking a motor price for Sam with a different company, I am still unsure if I can release that. I will ask for clairification soon. 

If you are interested in Battery Pack to AC, with medium to large numbers to deal with, Website: www.appliedps.com Email: [email protected] 

Best Wishes All,


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## Anonymous Expert (Oct 25, 2009)

Morf said:


> Dear DC to 3 phase AC Inverter Fans,
> 
> This is an update on my communications with Applied Power Systems, after I emailed them with my general early ideas for powering my PM Oswald Synchronous 3 phase Motor in a lite utility van.
> 
> ...


You'll have to ask Les but I'm pretty sure that the APS controllers don't do flux vector control or any type of control that looks at a speed sensor on the motor. This means low speed performance would be poor. You would end up shoveling in loads of current but not getting much torque. Vector control is a neccessity for a ac traction application in my opinion.


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## peggus (Feb 18, 2008)

Really? the EV1 did not use vector control, it was quite zippy. 

ACP did not use vector control in their early drives, I'm not sure what their latest models do but the Tzero was quite zippy and efficient without vector control.






Anonymous Expert said:


> You'll have to ask Les but I'm pretty sure that the APS controllers don't do flux vector control or any type of control that looks at a speed sensor on the motor. This means low speed performance would be poor. You would end up shoveling in loads of current but not getting much torque. Vector control is a neccessity for a ac traction application in my opinion.


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## major (Apr 4, 2008)

peggus said:


> Really? the EV1 did not use vector control, it was quite zippy.
> 
> ACP did not use vector control in their early drives, I'm not sure what their latest models do but the Tzero was quite zippy and efficient without vector control.


Hi peg, 

Would you please site your sources on this?

I would be very surprised if they did not use closed loop flux vector drive. I know for a fact that the EV-1 used an encoder on the motor. And it didn't work without that encoder. Maybe you call it by another name, but when velocity feedback is used to control torque, it looks like flux vector to me. I'm no PhD, so correct me if I'm wrong. Please.

major


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## samborambo (Aug 27, 2008)

peggus said:


> Really? the EV1 did not use vector control, it was quite zippy.
> 
> ACP did not use vector control in their early drives, I'm not sure what their latest models do but the Tzero was quite zippy and efficient without vector control.


Ask etischer (forum member) about the performance difference between V/Hz and flux vector. I recall the difference for his modified inverter was "like night and day".

Sam.


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## samborambo (Aug 27, 2008)

Morf said:


> Following up with a phone call, I learned that APS`s custom build components are derived from base units that APS has a history with.
> Their components are updated and friendly to different environments. Engineer Les Doti sent me papers on their 150 kW 3 phase inverter, liquid cooled. He says it will easily get me the output of 170 amps, even when switching at 10kHz. He then explained the benefits of this model over the next size smaller one, specifically pointing out that the smaller one would run hotter.


I wouldn't be too concerned with running the inverter cooler for your application. If the peak current rating can be met by the smaler inverter, go for it. In an industrial plant I'd definitely oversize the inverter because it'd probably be running close to 100% load 24/7. The inverter driving your vehicle will be running a duty cycle of around 20% at the worst (unless you're planning to do some rally driving).

The engineer you spoke with would deal almost exclusively with industrial applications, not automotive. Make sure he's aware of your duty cycle requirements.

Sam.


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## Morf (May 29, 2009)

Anonymous Expert, Hi,

My conversation with engineer Les was almost entirely devoted toward figuring out a proper inverter for my project at this time. The inverter that is now up for consideration is a half of an existing component that is labeled `DMT Windmill Application`, that gives me the choice of air or water cooling, and the photo I have shows the option of an eleven inch chill plate. 

When I slipped over into discussing motor control, Mr. Doti reminded me that issue would belong to the second half of our potential project. I had given him my plan which was for a utility van, somewhat Modec like, along with the information from the motor tag on the Oswald PM Synchronous motor. The motor has an existing encoder UT type SRM 50 and I doubt that we talked about it. 

Back to the inverter, the larger capacity inverter is available for less than $200. difference. The only difference in the two inverters comes down to the size of the IGBT transistors being used. 

Thanks to all who have taken time to comment. I am taking notes to be used in my next call to APS. And should I make an effort to get Trench IGBTs in the inverter, due to their reduced power loss in these applications? (Power Electronics Europe, Issue 4, 2008) www.irf.com PCIM 12-202 Cheers.


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## etischer (Jun 16, 2008)

samborambo said:


> Ask etischer (forum member) about the performance difference between V/Hz and flux vector. I recall the difference for his modified inverter was "like night and day".
> 
> Sam.


Vector control can be done without an encoder, this is how my controller works. My inverter uses motor current feedback to determine motor RPM. This is refered to as "Sensorless Vector" control. If I add an encoder, it would be considered "Closed Loop Vector" control. 

I also have the option of running V/Hz. It is good for diagnostics since it is a very primiatve mode. 

For a drag racer one could clearly define an accel curve, add some DC boost at low RPM and run a decent drag race in V/Hz mode. It would not be feasible to drive the car on public roads this way though. The low speed torque capablities running under vector control is the primary advantage. 

In V/Hz I could barely make it up my drive way in 1st gear (starting from a stop). 
In sensorless vector I can make it up in 3rd gear, or burn rubber the entire way in 1st gear.


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## etischer (Jun 16, 2008)

Morf said:


> Dear DC to 3 phase AC Inverter Fans,
> 
> Engineer Les Doti sent me papers on their 150 kW 3 phase inverter, liquid cooled. He says it will easily get me the output of 170 amps, even when switching at 10kHz.


I would verify if it is 170 amps per phase, or total for all 3 phases. Some inverter companies like to market their inverters by adding the 3 phases together and stating that as the motor current. Motor current is generally the current in just one phase. The inverter may be undersized if you don't recognize the difference. 

Adding the 3 phases of current together makes it easier to do a side-by-side comparison with a DC motor controller.

I rate my inverter as 84kw, which is around 290 amps per phase. This is with a bus voltage of ~300v.

I would also verify this "windmill" inverter is capable of Vector control. I imagine a windmill would run simple v/hz mode (regen can be done in v/hz).


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## peggus (Feb 18, 2008)

Former and present coworkers, some of whom worked directly on the impact project. 

The inverter was designed long before AV even considered putting a dsp into anything. The inverter for the EV1 used torque slip control hence the encoder.The controller was mostly analog. There was a lookup table in a ROM for determining the optimum V/Hz ratio for any given input. 

Cocooni then went on to start ACP and designed another analog inverter.





major said:


> Hi peg,
> 
> Would you please site your sources on this?
> 
> ...


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## major (Apr 4, 2008)

peggus said:


> The inverter was designed long before AV even considered putting a dsp into anything. The inverter for the EV1 used torque slip control hence the encoder.The controller was mostly analog. There was a lookup table in a ROM for determining the optimum V/Hz ratio for any given input.


Thanks peggus,

Kind of seems like the old fashioned way of doing the same thing we now call flux vector control. Just using analog and look-up tables instead of dsp and Clark & Park transforms.

Now that you mention it, about that time, 1994/95, I got an early version of a vector control card just introduced. It was one of the first on the industrial drive market, I think. And the Impact development was a few years before that. How time flies.

Regards,

major


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## yarross (Jan 7, 2009)

major said:


> Kind of seems like the old fashioned way of doing the same thing we now call flux vector control. Just using analog and look-up tables instead of dsp and Clark & Park transforms.


This is something different, may be called scalar control. Does not decouple stator current into torque and field components, so you can't control them like in SepEx. Still provides torque control suitable for traction drives, but it's response is somewhat slower and it needs lookup tables that are specific for each motor (vector control requires only few parameters, all it needs is calculated on the fly).


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## Kelmark (Oct 26, 2009)

*Re: New controller prototype*



EVComponents said:


> We are looking into it. It will likely be called the Tri-Zilla. Otmar already took a stab at it with one early version.
> It will be a project hopefully that has something real to show in 2010.


Have you seen this 144V kit?
http://www.emduro.eu/index.php?option=com_content&view=article&id=10&Itemid=33

It looks promising maybe it is something that could be offered through EV Components here in the states... I am little worried buying something from overseas that hasn't been tried and proven here in the states. Also warrenties are easier if working with a distributor here in the states.

Any thoughts?


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## JRP3 (Mar 7, 2008)

Something to keep an eye on, looks as if they have a little while before it's actually ready: 
*Electric propulsion system AC-144-50 is still in stage for testing. We are planing to present this product for worldwide market on 2010-05 *


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## few2many (Jun 23, 2009)

*Re: New controller prototype*



Tesseract said:


> Sure you can get them used for barely their scrap value, but why would you want to design a complicated product that relies on scrounging for used motors to be economically viable?


You dont seem to mind you're $3500-$4500 controller being used for old forklift motors.
Wow, longest time ever recorded for a comeback!


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