# Homebrew Build



## generatorlabs (May 31, 2014)

*Homebrew AC Controller Build*

Just thought I would post a build progress on my AC controller.
I am currently working on fabricating the chill-plate.
Using a CNC machine I built a while back.
The electronics are almost done.
As you can see in the photo the electronics are mounted on a cardboard backer just for the initial tests and to keep anything from shorting while I move things around.
The electronics are from the J Huebner kit. You can see more information about that kit on another thread in here

Open to any suggestions for improvement. Haven't really thought out the entire build so I am fabricating on the fly.


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## bwjunkie (Jul 31, 2013)

looks cool to me! (is that Donkey Kong in the background?)

Also, what size is the coolant tubing , what type of coolant and how will you be affixing them inside the grooves?
-josh


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## generatorlabs (May 31, 2014)

Yes that is Donkey Kong in the background! That was my "I didn't have anything to do last summer" project. That is a full sized MAME cabinet that is running off an old PC and some scrap furniture grade plywood. Got it loaded with all the classic coin op games! Every garage should have one. With all the old PC's I see put to rest at my local dump it saddens me. Re-use and re-purpose is the name of the game. I used another old PC to build the CNC machine I have that cut this chill plate (that was the project of 3 summers past)

My project for this summer is the AC controller 

The machined fluid channel is 1/2 by 1/2 inch so I used those brass hose connectors which have an inside diameter of 1/2 inch. Typical 5/8 OD hose should work fine there with some hose clamps. I will probably use glycol fluid in the chill plate. I have access to tons of it at my job. Everyday anti-freeze is just as good. The hose bibs are mounted on the chill plate cap and are mechanically centered over the beginning and end points of the fluid channel when the cap is screwed down with all those 1/4" bolts.


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## generatorlabs (May 31, 2014)

So I made a little more progress:

Verified that pulse train is working

Here are the waveforms from the IGBT driver boards.

Note the voltages that are required to trigger large IGBT's

Also note the required dead-time between the phases. It is difficult to see on the first photo but once you zoom in it is apparent on the second photo. I know I am stating the obvious here but I will throw it in just in case someone is new to this. I was that guy at one point right? Low or no dead-time will lead to catastrophic failure.


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## generatorlabs (May 31, 2014)

A little more progress:

Machined some construction grade PVC board to make a mount for my driver boards and terminated drivers to the IGBT's.

Waiting on a delivery of copper bus bar and then I can do some higher voltage testing.


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## generatorlabs (May 31, 2014)

Got a little further today.
Ordered some very nice copper bus bar that I drilled & installed.
I haven't really decided how I am going to bring my power cables in so I left them longer than necessary for the time being. Remember, I am designing on-the-fly 

So I am not quite courageous enough to go ahead and put massive current across these IGBT's just yet. I still need a massive capacitor network, some snubbers and a mains fuse. But you know I couldn't resist doing a little something. I put a bench supply in the circuit and drove a tiny 3 phase radio controlled helicopter motor. A video snippet of it running can be seen here:

https://drive.google.com/file/d/0B0yvjhlC62G7SnZfeklPbGZTYnMyRWlFZF9LNFRjSEpJelRZ/edit?usp=sharing

There is still much work to do but this is a promising start.
.
.


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## kennybobby (Aug 10, 2012)

i guess that a next-generation design would not have the bolt heads and coolant taps protruding out the bottom--makes it difficult to sit flat while assembling on the bench.


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## generatorlabs (May 31, 2014)

I wrestled with the idea of having the coolant outlets machined in the side of the plate but I decided against it for the following:

a) The main plate is only 3/4" thick. If I wanted to put fittings on the edge of the plate I would have to use smaller threaded hose connector. I didn't want the fitting to be a flow restriction. I used 1/2" NPT connectors. The final machined wall thickness on the top and bottom would be too thin for my comfort. I was envisioning a possibility of slight deforming of the thin walls when tapping or screwing the tapered fitting into soft aluminum. The plate cap and chill plate must remain absolutely flat to maintain a positive seal. When the bolts are tightened the chill plate and cap will be absolutely flush with each other, almost appearing as a solid piece. I did not want to see the NPT thread forming a small bulge when driving the fitting in.

b) I could have bought thicker 1" aluminum but the cost rises exponentially as the thickness increases.

So after debating it in my mind I decided I was going to do one of two things. I would put a number of vibration dampening spacers under the unit to afford me space in my final mounting solution (as shown in the attached photos). I was also thinking of just tapping some bolts into the edge of the chill plate and mounting some beefy aluminum L shaped stock.

Anyway you are correct, it is not ideal placement for the hoses but I do not have an infinite budget for this project so it seemed like a good compromise and it in no way effects performance. In the long run it may turn out to be far cooler this way. For the time being I can live with it not sitting flat on my workbench. I am more concerned with function over form. Sometimes that is how it goes when designing on-the-fly


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## Tesseract (Sep 27, 2008)

generatorlabs said:


> ...I still need a massive capacitor network, some snubbers and a mains fuse. But you know I couldn't resist doing a little something. I put a bench supply in the circuit and drove a tiny 3 phase radio controlled helicopter motor....


Be very careful running even miniscule voltage and current levels through the IGBTs without any decoupling (aka "snubber") capacitors mounted on the bus bar. I managed to blow up a 1200V/600A IGBT module while bench testing a gate driver design at a mere 24V because I was too lazy to mount a snubber cap right on the module... That was a $200 mistake.

However, if you do manage to destroy one or more of those CM400DU modules during testing, I just happen to have several boxes of them which I purchased from the Azure Dynamics bankruptcy auction...


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## generatorlabs (May 31, 2014)

Tesseract said:


> Be very careful running even miniscule voltage and current levels through the IGBTs without any decoupling (aka "snubber") capacitors mounted on the bus bar. I managed to blow up a 1200V/600A IGBT module while bench testing a gate driver design at a mere 24V because I was too lazy to mount a snubber cap right on the module... That was a $200 mistake.


Wow..thanks for the heads-ups. Amazing that these things can crush 400 amps but could get toasted at 24V with little current.


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## aeroscott (Jan 5, 2008)

generatorlabs said:


> Got a little further today.
> Ordered some very nice copper bus bar that I drilled & installed.
> I haven't really decided how I am going to bring my power cables in so I left them longer than necessary for the time being. Remember, I am designing on-the-fly
> 
> ...


 In the commercial units I've seen they laminate the bus bars for induction reduction. Nice looking work.


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## generatorlabs (May 31, 2014)

aeroscott said:


> In the commercial units I've seen they laminate the bus bars for induction reduction. Nice looking work.


Thanks for the comments 

When you say "laminate" do you mean they encapsulate it in a resin or something? 

I was going to put large black and red shrink tube on the exposed bus sections just as a safety thing but I don't know if that would achieve the same effect as what you are describing. Waiting on my snubber caps and main caps before I do anything else with the rails.


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## aeroscott (Jan 5, 2008)

If we make 2 large sheets of conductors ,each sheet covers the of + and -
then say starting with the + side . The 3 holes are drilled to fit. Then the - side of this bar are oversized for insulators and a conductor ring that will be insulated or isolated from the + bar and high enough to reach the bottom of the - bar . After the + bar is on a insulation layer is bonded to it. Then the same is done with the - bar except the - holes are drilled to fit and the plus are oversized . I haven't seen any of these in over a year so the details may be off. The other thing I remember is less mass in the bars
means less inductance . And there may be some advantage to more thin layers then a single thick one ( inductively). As an example I'm taking apart a Chevy Volt . It uses 1" wide by less then 1/5" "bar" made of laminations . If I remember right battery cables have a lot of inductance that will have negative effects on the igbt's. So this laminated bar helps reduce the need for caps.


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## generatorlabs (May 31, 2014)

aeroscott said:


> If I remember right battery, cables have a lot of inductance that will have negative effects on the igbt's. So this laminated bar helps reduce the need for caps.


That is awesome. Kinda sounds like those layers of copper form a rudimentary capacitor in itself! Definitely something I will explore.


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## aeroscott (Jan 5, 2008)

It does sound like a capacitor . 
I looked over the Volt battery conductors , it looks like about 10 laminations , total thickness 1/8"X less then 1" for about 400 amps.
200 hp and 360 volts.


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## generatorlabs (May 31, 2014)

No real news on my build except that I mounted snubber caps.
Still waiting on main caps.
But now that I have snubbers on there I feel a little better about bringing that tiny 3 phase motor up to some higher speeds. I got it to go pretty fast. I had to push it off with my fingers to get it started. I am sure I have to play with some more parameters to improve that. My bench power supply cannot supply much current either so that may also be a factor.


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## generatorlabs (May 31, 2014)

Attached a pot to the circuit to mimic the operation of a pedal with the controller.

Here is a better video showing my small 3 phase motor being ramped up to some higher RPM's.

http://youtu.be/1czxlANtqbQ


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## kennybobby (Aug 10, 2012)

Looking at your pictures i see two things you might want to consider for your build:

1. Typically the igbt gate drive will be thru a twisted pair of wires instead of two separate wires with a big air gap. This is to reduce EMI noise and the possibility of firing both gates at the same time. That big loop created by your white and green wires acts like an antenna to radiate and receive unintended signals.

2. Flat ribbon cable is notoriously unreliable, especially for critical applications. It may be fine for benchtop prototypes in the lab, but is not a good solution in a vibration environment such as an EV. A sliding electrical contact that relies on weak spring pressure to maintain continuity should be avoided.

3. Focus on the oscilloscope settings and measurement traces so we can tell what is being measured and what it shows about your circuit.


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## generatorlabs (May 31, 2014)

> 1. Typically the igbt gate drive will be thru a twisted pair of wires instead of two separate wires with a big air gap. This is to reduce EMI noise and the possibility of firing both gates at the same time. That big loop created by your white and green wires acts like an antenna to radiate and receive unintended signals.


I have had others recommend changing that as well. I will definitely address that in the next few days. Thanks. While I think these particular IGBT's would require a significant amount of stray current to produce a false trigger it is better to be safe than sorry.



> 2. Flat ribbon cable is notoriously unreliable, especially for critical applications. It may be fine for benchtop prototypes in the lab, but is not a good solution in a vibration environment such as an EV. A sliding electrical contact that relies on weak spring pressure to maintain continuity should be avoided.


Those are not my favorite connectors either. I plan on replacing the ribbon feeding the IGBT drivers with twisted pair cable for some noise rejection. In the interim I also plan on relying on old motorbike racing techniques to keep the other ribbon cables latched. I am going to drill tiny holes in the plug/jack latches and tie them together with safety wire making it impossible for the plug to be removed without first cutting the safety wire. If I do make it to the point where I actually install this in a vehicle I will probably hard-wire everything point to point. I am so far away from that reality at the moment.



> 3. Focus on the oscilloscope settings and measurement traces so we can tell what is being measured and what it shows about your circuit.


Will do.


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## generatorlabs (May 31, 2014)

I got my main capacitors in yesterday.
So I have been tossing around ideas on how to mount them.
Remember I am designing this on the fly  so let's see how it goes.

I decided to try using some more of that white PVC board to make cap holders. Machined a pair of them. It got kinda late here so I could not finish so I will continue tomorrow. Tomorrow I will shave off the fake wood grain and also make the brackets a little smaller by shaving off some of the excess PVC material.

Also I machined the holes for the caps to the exact size. I want a clamping action on them to prevent movement so I will cut the brackets in half, forming a lower and upper half and then use machine screws to hold the two halves together sandwiching the caps in place.

I have a nice aluminum plate that I will mount the caps to. I was thinking of machining an access hole in the plate (as shown by the marker outlines) to pass flexible bus-bars thru and connect direct to the main bus-bars. The plate would be mounted directly above the IGBT's.

Here is the CNC in action. Sorry, videographer I am not.

http://youtu.be/1CcyO-kTokI

I am looking for suggestions or observations or "No-No's" about mounting the caps in this fashion.

Thanks for looking.


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## generatorlabs (May 31, 2014)

Cleaned up the capacitor tray today.
Added some access holes to the plate for passing large wires to main bus.
Don't know which holes I am using but I put three there for some options.
Cut down the plastic PVC brackets. Cut slits in the brackets to allow some clamping force on the caps. Drilled holes and used 3" machine screws and nuts to secure the who thing.

Net step is to fabricate some large stand-offs so I can mount this assembly above the IGBT's.

As always, if any of you observe any potential problems with what you see here, I invite your input.

Thanks for looking


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## jhuebner (Apr 30, 2010)

Again, nice work 

How are you planning to connect the caps to the bus?
Why don't you use two single copper strips across all caps?

Your setup doesn't look "as low inductance as it gets" but I can't judge whether that poses a problem. Other members are probably more knowledgeable about this.


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## generatorlabs (May 31, 2014)

jhuebner said:


> Again, nice work
> How are you planning to connect the caps to the bus?
> Why don't you use two single copper strips across all caps?


Thanks for the comments.

Those small copper strips are actually copper pipe hangers that I saw laying around my local Home Depot. Unfortunately that was the only length they had so I had to use four but they are cheap. It may not be my final solution but it is a cheap way for me to mock up the build for now. Since those strips are semi-rigid I was going to use two more to extend down to the DC bus, and bend some angles into them. I was going to bolt them all together and possibly braze the segments together to ensure a solid connection.

If I can get my hands on some heavy braided wire I may try that too. I have seen that used in a number of Mitsubishi forklifts in the past. I think that stuff is kinda pricey though.


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## generatorlabs (May 31, 2014)

This thing is starting grow.
Made some stands-offs from scrap metal.
2nd tier complete.
Oddly I machined 4 stand-offs but could only use 3. The 4th stand-off would have penetrated the water jacket. It is still very rigid with 3 posts though.
This is what I get for doing this stuff on-the-fly. 
Next: Mounting locations for main and current sensor boards. From what I can see, the main board can get mounted upside down directly beneath the caps.


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## onegreenev (May 18, 2012)

Question! Why 4 caps? You doubling up on them?


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## generatorlabs (May 31, 2014)

onegreenev said:


> Question! Why 4 caps? You doubling up on them?


I assume you mean that I am doubling up the caps compared to J Huebners build right? I believe the caps he has are higher value capacitance.

Also since the DMOC controller looks to be a somewhat respectable design I am copying some aspects from that build. From videos I have seen of the DMOC, it uses IGBT's and a capacitor banks similar to what I have used here.

Lastly I found a very interesting guy (Damien Maguire, I beleive in the UK) who tore down a DMOC and also built a controller similar to this. He has a number of videos posted on YouTube. 

Maybe it's overkill; maybe there is no advantage to having a beefy reserve in this design. I guess in my mind I am paralleling audio amplifier design and this controller design. The better amps always had the more robust power supply to feed those hungry transistors . Since I bought these caps as surplus they were cheap compared to buying new ones so it didn't hurt my wallet too bad. New large caps are expensive!


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## generatorlabs (May 31, 2014)

Here is the controller connected to a large 3 phase motor.

Sorry for the distortions in the video. I had to apply shaky-cam filters to the video or you would easily get sea sick from my novice cinematography skills. The filters however create their own set of problems.

http://youtu.be/zpJWGD5JtLA


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## major (Apr 4, 2008)

Good job 

It is a shame they trash those motors due to a $100 sensor bearing failure. But on the other hand, they end up in your garage  

Do you have a scope? You should look at the C to E voltage on the switches. That will become critical as your current increases.


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## generatorlabs (May 31, 2014)

major said:


> Good job
> 
> It is a shame they trash those motors due to a $100 sensor bearing failure. But on the other hand, they end up in your garage  Do you have a scope? You should look at the C to E voltage on the switches. That will become critical as your current increases.


Yes I do have a scope. I was running out of space on my small workbench and I generally do not keep my nicer tools in that area. I will set up another table and see if I can get some shots of the waveforms in the next video. To be honest though I don't really know what to look for. When I look at the input side of the IGBT's the waveforms are really predicable and I believe I have the dead-time properly tuned in. However when looking at the output, there is a lot of transient activity. The scope does not lock onto the waveform quite as easily either. I may have to mess with filtering and triggering some more to dial it in. If you have a link to a thread with a typical waveform for comparison that would be great. The other question in my mind is how to correctly set up two channels to view the waveforms if they share a common ground plane (which also happens to be tied to earth ground). I do not have differential probes. Johannes suggested that he uses a simple scope without differential probes with good results. In my mind the ground plane still does not compute and I do not want to harm my scope by doing something dumb. Most of my projects were in the low voltage realm. Dealing with high voltage across multiple phases would be a first for me. Any tips would be helpful.

Thanks


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## generatorlabs (May 31, 2014)

Here is a continuation of the video I put up the day before yesterday; more of a follow-up video with some additional information....nothing groundbreaking....more like me just rambling. But someone may find some of this useful. I did put up some footage of waveforms from my scope and I invite anyone to analyze what is going on there. I don't know what would be considered bad information in that waveform.

Sorry for the distortions in the video. I had to apply shaky-cam filters to the video or you would easily get sea sick from my novice cinematography skills. The filters however create their own set of problems.

http://youtu.be/ZdtBWLAn-RM


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## generatorlabs (May 31, 2014)

So busy this week; have not been able to do much with the controller.
I did rework the DC bus for the caps. I had thin wires running there and they were getting warm to the touch. I think this will work much better. I will observe it closely the next few days. It is made of scrap pieces of copper pipe hangers. I soldered together any overlapping conductors.

A buddy of mine sent me a scavenged contactor. Bars on it are pretty beefy and the tips look to be silver. Any comments on using a contactor like this would be appreciated.

On a side note I test drove an electric BMW i3 this week. It is an unusual car to say the least. It did have some neat torque though. I think the car is much too expensive for what it is but it is still nice to see that companies are putting a real effort into these types of vehicles these days. The technology is there and in its infancy. I can only imagine what they will be like in 10 years.


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## generatorlabs (May 31, 2014)

The universe has been kind to me this week. 

As I was strolling around my job inspecting the network I decided to stroll through the mechanics shop to see if there were any scraps of wire laying around. The shop manager pointed me to what I thought was a blue air hose. He told me it was a heavy duty truck coupler that had bad ends on it. The ends are huge industrial plugs. The cable had been repaired once but had failed again so it was headed towards the dumpster.

Another persons trash is my treasure. Below is a picture of the coily cable. It is mega thick and when stretched out it is over 20 ft long. I tried to get the curls out but they just come back so I put the wires in pieces of PVC pipe to keep them from looking like spaghetti on my bench.

I didn't have any large crimp end for the cable so I made some from copper and for the motor end I made a lug by soldering the wire into a loop with a small torch. The loop was flattened with a hammer once it cooled down. Temporary remedies for now but no more thin, over heated cables for sure.

Also got the encoder wired up and verified it is outputting 80 pulses per revolution. May need to add shielding to the encoder cable though.


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## generatorlabs (May 31, 2014)

Got encoder to work with motor & controller.
Now controller can take advantage of Torque mode.
With the beefier cables I salvaged I can get some respectable speeds very rapidly without fear of melting any wiring insulation 

Ran motor at @ 900 RPM for a short while to gauge the amount of heat generated by the IGBT's. Plate was just warm. Next time I run it I will pump water through it to see if I can keep it at room temp. Need to buy (or salvage) some hose.

Here is what I got when I ran it:
http://youtu.be/I3Hj_xZGU70

Next step: mount main board permanently. Will post that when done.


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## jhuebner (Apr 30, 2010)

I'll just reply on the oscillating question here so everyone sees it.

So the way the speed limit is enforced is very very basic.

For programmers, this is done on every PWM cycle

if (frq > fmax) fslip = 0;

So the slip frequency is set to 0 resulting in 0 torque. That in turn will reduce the speed eventually. When is reaches a value below fmax the commanded slip is used again resulting in the commanded torque. Not immediately though, because the rotor is demagnetized. So the time constants involved in this cause the oscillation you observe.

I'll eventually change the speed controller to PI or ramp type that acts on the torque command.


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## Tesseract (Sep 27, 2008)

OP: those scope traces show an awful lot of ringing and overshoot. While your probing technique or equipment could make these artifacts appear worse than they are (you really need to use a scope with floating, isolated inputs, or else a differential probe), your bus layout and seemingly lax approach to capacitor selection are most definitely the source of the artifacts. The most critical current pathways in an inverter are between the DC link (ie - input) capacitor and the half-bridge switches (also between the two switches in each inverter leg, but that connection is made inside the module so not much you can do about it).

Using big can-style electrolytics for the input capacitor(s) does not absolve you of the need for smaller 1-2uF box-style snubber capacitors mounted directly on the DC link terminals of each IGBT module.


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## generatorlabs (May 31, 2014)

Tesseract said:


> Using big can-style electrolytics for the input capacitor(s) does not absolve you of the need for smaller 1-2uF box-style snubber capacitors mounted directly on the DC link terminals of each IGBT module.


Thanks for your input. I have been battling the o-scope issue in my mind for some time. Scope class 101 always warned of the potential of hazards when using scopes on line current with respect to earth ground. Fortunately some of that info actually stuck to the inside of my cranium. The differential probe thing is quite cost prohibitive for me, especially for a tool that will not get used on a regular basis. It is funny that two decent probes cost more than the scope itself! Someone suggested I remove the ground lug from the AC cord but that does not negate the fact that the two BNC inputs share a common ground plane and it did not seem logical being that the controller has no reference to earth anyway.

As for the snubber caps.....are you suggesting that I put another set of snubbers on the DC rails in addition to the 3 snubbers already there? 

Thanks


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## Tesseract (Sep 27, 2008)

generatorlabs said:


> ...The differential probe thing is quite cost prohibitive for me, especially for a tool that will not get used on a regular basis. It is funny that two decent probes cost more than the scope itself!


Yes, a good differential probe is expensive. So is a scope with floating, isolated inputs like mine: AEMC OX7104

The fact of the matter is that you can't really design power electronics without one or the other of the above. In the meantime the best you can do is to isolate the supply to the inverter using either a transformer or batteries (don't disconnect the ground from the scope - it doesn't help with the noise and just makes the whole scope a safety hazard) and just probe one power signal at a time - and not at the same time as probing a low-level signal (ie - don't try to look at the PWM signal going into the gate driver at the same time as the output from its IGBT leg).



generatorlabs said:


> As for the snubber caps.....are you suggesting that I put another set of snubbers on the DC rails in addition to the 3 snubbers already there?


No, I'm saying you need to work on reducing the loop area of the DC link. The comment about the snubber caps was only to emphasize that the presence of the big electrolytics does not negate the need for them.


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## jhuebner (Apr 30, 2010)

Tesseract, you know I have to 

As I mentioned somewhere else I did the whole inverter work with a non-isolated analog scope from the seventies. As long as the inverter runs off batteries the scope IS isolated.

That said I was never on the quest to perfection, I did the best I could with snubbers and caps standing upright on the bus bars and was happy not to see excessive ringing or spikes.

I do second the comment on the capacitor connection/selection, its certainly not as good as it gets. I'm just not sure if it poses any other than an esthetical problem as long as the bus voltage is below 1/2 of the IGBT rated voltage.

I just found a funny picture on my cellphone from the factory inverter of my old (23 years) electric car. Check it out:










These are the actual bus caps 

This is for sure not engineering perfection. It must have been ringing like hell. But it still did the job.


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## Tesseract (Sep 27, 2008)

jhuebner said:


> Tesseract, you know I have to
> 
> As I mentioned somewhere else I did the whole inverter work with a non-isolated analog scope from the seventies. As long as the inverter runs off batteries the scope IS isolated.


Yes, running the inverter off a battery pack was one of the suggestions I made... So not sure where the argument is here. 



jhuebner said:


> That said I was never on the quest to perfection, I did the best I could with snubbers and caps standing upright on the bus bars and was happy not to see excessive ringing or spikes.


Switching the IGBTs slowly - particularly during turn-off (which, btw, is not really under your control via gate resistor selection; only turn-on speed) - will also greatly help in reducing ringing.

Then again, we have this saying in the US: Even the blind squirrel finds a nut now and then. 



jhuebner said:


> I do second the comment on the capacitor connection/selection, its certainly not as good as it gets. I'm just not sure if it poses any other than an esthetical problem as long as the bus voltage is below 1/2 of the IGBT rated voltage.


Ringing is far more than an "aesthetic" problem; it is a potent source of high frequency EMI that can wreak havoc with the signal-level portions of an inverter. Erratic throttle response, jumpy current readings, oscillation to even outright locking up the microcontroller are all possible. 

Furthermore, ringing can couple quite efficiently through the so-called Miller capacitance between the collector and gate of an IGBT, causing it to enter into thelinear part of the transconductance curve. This usually causes failure soon after as a result of those old foes of bipolar transistors: second breakdown and current crowding (switching IGBTs and MOSFETs are very poorly suited to linear use).

Finally, that ringing may cause problems with other devices in the car, like the radio, cruise control, climate control, seat adjustments, etc... Remember, the worst source of EMI that the OEM had to contend with was a spark plug; a 50kW+ inverter is a far more potent source of interference, particularly if it doesn't switch cleanly.


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## jhuebner (Apr 30, 2010)

Yes, I know what effects ringing CAN cause. What I'm saying if its not strong enough to cause any of these, why be bothered to optimize?
He placed the main board with many unshielded cables around his setup and even the most sensible input - the encoder - is not seeing false pulses.

The laptop is close by and the touch pad still works. One of the first components to give in on excessive EMI.

Tesseract, I know your comment is absolutely legit. I'm just missing the part where you say "look, this is a potential problem, it may be irrelevant but keep an eye on it". It sounds more like "what the hell are you doing".

Of course if generatorlabs knows how to read your warning my whole post is irrelevant


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## Tesseract (Sep 27, 2008)

jhuebner said:


> Yes, I know what effects ringing CAN cause. What I'm saying if its not strong enough to cause any of these, why be bothered to optimize?


Perhaps *you* have the experience and knowledge to determine when to worry about ringing and when not to, but the OP has clearly stated he is a hobbyist/tinkerer and thus it is unreasonable to expect him to possess the same level of judgment and ability.



jhuebner said:


> He placed the main board with many unshielded cables around his setup and even the most sensible input - the encoder - is not seeing false pulses.


He is also running at very low power at this point...



jhuebner said:


> The laptop is close by and the touch pad still works. One of the first components to give in on excessive EMI.


This is a good trick and one that I use, too, as a quick-and-dirty EMI detector.



jhuebner said:


> Tesseract, I know your comment is absolutely legit. I'm just missing the part where you say "look, this is a potential problem, it may be irrelevant but keep an eye on it". It sounds more like "what the hell are you doing".


You're right - you are missing the part where I say this, "...may be irrelevant," because I don't think the ringing is irrelevant. In fact, I think ringing should always be treated as a potentially serious problem until it can be determined - at least with reasonable confidence - that it is either harmless (ie - will never interfere with other parts of the circuit or other devices in the vicinity) or else an artifact resulting from limitations in the test equipment and/or setup. 

Frankly, your apparent dismissal of the ringing/overshoot in the OP's scope plots seems a bit irresponsible to me.


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## generatorlabs (May 31, 2014)

Thanks for the feedback....

I honestly see the logic behinds all the comments here. In the end I will do the best I can with the financial resources I have but along the way I will consciously try to build this with my best attempt to follow best practices, working models and comments in here.

For example, I did try to snipe one or two differential probes from ebay, however I got outbid by 20 or so dollars in the end. I am sure some probes will fall into my lap at some point for a great price. I just have to play the waiting game until then because I would rather spend my money on higher priority things.

The thing about the touch pad on my laptop being affected by noise is one thing that never occurred to me. That is brilliant and now that I think back the touch pad is not affected at all. Good nugget of information for future use.

I ran the motor at much higher frequencies last night and at a higher voltage. I did not have any thermal issues of electrical mishaps. In fact it seems to run cooler and smother at the higher voltage. Short video of it can be seen here:

http://youtu.be/pgLlOBYO03A

Thanks for looking, and as always, the comments are always welcome and invited. When you do comment, I learn. I may not be able to implement the suggestions but it does not mean I do not learn from it


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## jhuebner (Apr 30, 2010)

150A, nice.

I made an experiment: how bad is your ringing?

Maybe it helps your ringing intuition.


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## generatorlabs (May 31, 2014)

Got home late today so could not really do much with the controller.
Made some small updates.

Mounted main board to a fixed location.
It is now upside down under the capacitor tray.
I was also meaning to update the wiring between the driver boards and the IGBT's. Those wires are now twisted pairs to offer noise rejection (white and green wires in the background).


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## generatorlabs (May 31, 2014)

Water cooling tested today.
Pump and hoses connected. Hoses are clear rubber and are not recommended for an actual install but they were donated to me and I really appreciate any help I can get.

The hoses and pump do not terminate to an actual radiator/heat exchanger. Just used a jug for this test. I will probably use an aluminum automotive air conditioner condenser when I come across one.

Ran this motor for 15 minutes with no substantial change of temperature in the chill plate.

Here is a video snippet of the test:

http://youtu.be/8f9xsGChfYw

Thanks for looking


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## onegreenev (May 18, 2012)

You should use one of these flat plate oil coolers for your radiator or use a small auto motive radiator. I suggest the oil cooler type plates because you can put them flat. These allow great flow and cooling surfaces to cool your water.


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## generatorlabs (May 31, 2014)

onegreenev said:


> You should use one of these flat plate oil coolers for your radiator or use a small auto motive radiator. I suggest the oil cooler type plates because you can put them flat. These allow great flow and cooling surfaces to cool your water.


Thanks. Exactly what I was looking for! I think I saw these in the local RV shop however I think they were a little pricey.


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## rtz (Jul 3, 2013)

Various other ones:

http://www.bmracing.com/products/category/?maincat=Coolers 

Order one out of Jegs or Summit Racing. Always 10-20% off coupon codes floating around the net.


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## generatorlabs (May 31, 2014)

For those interested in electrical ringing in my controller, I invite you to look at this video. This video has no commentary, just motor whining in the background so you may want to lower you speaker volume. I attempted to zoom in on the display as best as I could. All pertinent information is on the screen including time division, volts division, etc. As much as I would like to have them, I do not have differential probes yet. All measurements were taken from L1 & L2 on the motor with respect to B minus of the DC bus.

Could readers please comment on what they see and if they feel if it causes a potential problem in this situation. Thanks!

http://youtu.be/S7SqYOYF0OI

One thing that is confusing me is this: The DC bus was the primary area readers were commenting on regarding ringing. I think my previous posts on this thread, http://www.diyelectriccar.com/forums/showthread.php/bad-ringingi-124865.html, show that ringing was not tremendous on the DC bus side (or maybe I don't know what to look for). The snubbers and main caps are suppose to capture a lot of that ringing energy but what is supposed to reduce ringing on the AC side?


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## jhuebner (Apr 30, 2010)

Ok, the ringing is only on the AC side not on DC. So please correct me if I'm wrong but this is not a DC bus problem.

Try using twisted pair cable on the short connection from gate driver to IGBT on one half bridge and see how it compares.

I have seen modules blow up because inside the cable from the terminal to the actual IGBT chip formed a loop.

I wouldn't judge the amplitude of spikes and ringing as alarming but they are definitely a pointer to a design issue.


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## generatorlabs (May 31, 2014)

jhuebner said:


> Ok, the ringing is only on the AC side not on DC. So please correct me if I'm wrong but this is not a DC bus problem.
> 
> Try using twisted pair cable on the short connection from gate driver to IGBT on one half bridge and see how it compares.


I updated the wiring to the IGBT's prior to this post. All IGBT's are already using short lengths of twisted pairs wire.

I was under the impression that the spikes created on the DC bus, as a result of the IGBT's slamming off & on at high frequency, was one of the big concerns here. This is where the snubbers kind of "snub" out or absorb the spikes right? This is where we want to monitor the maximum input voltage of the IGBT's, to make sure we don't stress the devices right? There is nothing on the other side of the IGBT, on L1, L2 or L3, that would accomplish the same effect right? I can understand concerns about inductance, design and loops on the DC bus side because noise-in equals noise-out but I cannot fully understand how you would impact ringing on the AC side if there are no active or passive components after the IGBT's to regulate any artifacts.

Still scratching my head on this one...


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## generatorlabs (May 31, 2014)

I just sold my Nissan Pathfinder. The cash offer was too good and I don't need a large people carrier anymore. Apparently Nissans & Toyota are a hot commodity in Mexico so top dollar is paid for used vehicles in great shape. There you have it; my faithful Pathy is destined to be shipped to Mexico next month. So long, good friend, you served me well!

I decided to stroll around the various showrooms of the local car dealers to look at EV options. I love the BMW i3 but it was a little too expensive for what it is. I don't like the look of the Nissan Leaf. Kind of excited about the VW e-golf and Kia Soul EV but those are not dropping until November with limited availability. I also looked at domestic EV's. One option was a Ford Focus EV with a lease of $194.00 per month. If I upgrade to leather it is $200 per month.

I also made inquiries into a Chevy Volt but have not gotten any prices for a lease worked up yet.

So now I am at a real cross roads. Do I get a new EV for a very low monthly payment or do I continue my quest of building a home brew EV. While the home brew EV thing is fun to experiment with I gotta wonder how long it would take me to finish one. I don't have a donor car or batteries yet. The only things in my favor are the fact that I have some good motors and a partially completed controller.

For me the math seems favorable to go with the new EV that will have all the amenities of a new car. I know this goes against the very nature of this forum but I need some advice. Does the Focus EV present a good value for the money and is it worth leaving this project alone? I am pretty sure I can recoup anything I have put into the controller by selling it and I have had many inquiries about my motors. Or should throw caution to the wind and press forward? The cost of batteries and proper charging systems to complete a homebrew EV is what makes me nervous.


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## piotrsko (Dec 9, 2007)

My answer is: I built my truck because I am a person who enjoys mucking about with widgets. the truck is fun to drive, but it will NEVER be finished, because there is way too much good stuff out there to install. Why buy something that is done? Rajesh bought a leaf, but he doesn't futz with things. We park in the lot next to each other at work and admire the other vehicle. I help him with his house and 220v charger project, he drags the extension cord so I can plug into the bus ports.

IMHO, you have a series of exasperating challenges to overcome just to start the process. I believe that to be propitious, others may argue, YMMV.


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## aeroscott (Jan 5, 2008)

Volt or Spark have great parts in them. The Spark lease is 199.00 with the new ones having the Volt LG battery tech ,400 ft.lbs. torque, planetary final drive. I believe these parts will be the hottest thing going . Its just getting through the can bus decoding. And they have Remi motors.


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## flyn_brian (Oct 21, 2012)

I for one would like to see you continue with the home brew build. But if you decide to sell it what kind of compensation would you be looking for? Feel free to send me a private message if you don't want to post it here.


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## Tony Bogs (Apr 12, 2014)

> Originally posted by *generatorlabs*
> I updated the wiring to the IGBT's prior to this post. All IGBT's are already using short lengths of twisted pairs wire.
> 
> I was under the impression that the spikes created on the DC bus, as a result of the IGBT's slamming off & on at high frequency, was one of the big concerns here. This is where the snubbers kind of "snub" out or absorb the spikes right? This is where we want to monitor the maximum input voltage of the IGBT's, to make sure we don't stress the devices right? There is nothing on the other side of the IGBT, on L1, L2 or L3, that would accomplish the same effect right? I can understand concerns about inductance, design and loops on the DC bus side because noise-in equals noise-out but I cannot fully understand how you would impact ringing on the AC side if there are no active or passive components after the IGBT's to regulate any artifacts.
> ...


Filters. Inverters need filters. Sometimes basic filters (aka RC snubber circuits) will do, but if the limit of the control of the rise/fall times of the IGBTs is reached, really big output filters are the only way to keep EMI and dV/dt in check. The main design goal is the maximum dV/dt the insulation of the motor can take. Usually 5V/ns for motors designed for inverter use, (much) lower for standard off line motors.

If I remember correctly, Johannes uses RC snubbers (with very low R values ).

Good work for a first try as a newbie.


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## skooler (Mar 26, 2011)

Tony Bogs said:


> Filters. Inverters need filters. Sometimes basic filters (aka RC snubber circuits) will do, but if the limit of the control of the rise/fall times of the IGBTs is reached, really big output filters are the only way to keep EMI and dV/dt in check. The main design goal is the maximum dV/dt the insulation of the motor can take. Usually 5V/ns for motors designed for inverter use, (much) lower for standard off line motors.
> 
> If I remember correctly, Johannes uses RC snubbers (with very low R values ).
> 
> Good work for a first try as a newbie.


Or just use pfc?


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## generatorlabs (May 31, 2014)

I am happy to say that I am allowing another member of this forum to continue where I left off with my homebrew controller. I have completed the Rev2 sensor board, tested it and have packaged the entire build to be shipped to Cali.

I do not think this will be my last build but at the moment I think I am going to purchase or lease a new electric vehicle. I am just waiting for some alternative builds to become available this November (particularly from Kia and VW).

I am sure I can complete a vehicle but the unknown factor is how much time it will take. I know I have the tools and equipment to do a complete build but I do not have unlimited free time on my weekends to tinker with it. I needed to get into a new vehicle anyway so this may be my excuse to get into a completely finished product. Also the Federal and State rebates are nothing to shake a finger at. I would still like to pursue a custom build but I would like to do it at a slower pace. In my next build I would prefer to have a nice donor car and some new batteries in hand before completing the controller.

The controller was very fun to build and I learned a great deal about it while digging through this site. I look forward to starting another one in the future.


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## bwjunkie (Jul 31, 2013)

I have enjoyed reading your thread updates, thanks for the efforts to build and post, very ambitious! best of luck to the next person.
-josh


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## onegreenev (May 18, 2012)

I will be continuing generatorlabs inverter build. I have a great AC motor for the project and I have a kit which I purchased so I will now have a complete one and a kit so if I blow something I can rebuild quickly and move along. I will need help with oscilloscopes but I think I will be ok with some basic stuff. Johannes has been a great help but my project was on hold and I wanted to get this thing moving along. Since generatorlabs was selling his I figured why not and it will get my project moving along much faster. I can take my time with the other inverter kit. 

Pete


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## Tony Bogs (Apr 12, 2014)

> Originally posted by *skooler*
> Or just use pfc?


 For the off line motors and a very long cable.


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## generatorlabs (May 31, 2014)

I always seem to find good deals here for bench and test equipment

http://www.circuitspecialists.com/digital-storage-oscilloscopes


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## onegreenev (May 18, 2012)

generatorlabs said:


> I always seem to find good deals here for bench and test equipment
> 
> http://www.circuitspecialists.com/digital-storage-oscilloscopes


Looking for one of those I can use that utilizes the computer screen as the monitor. They have one for the Mac but its not going to be out until Nov. They said it was Aug then Sept then Oct and now Nov. Sucks but if they come out with it I will buy one.


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## onegreenev (May 18, 2012)

Well I had been successful at running my motor with the Johannes Hubner DIY inverter kit that generatorlabs built. I let it sit for the winter while I recovered from surgery and then waited until it started getting nice again. I went out to start the motor and it would not communicate. I mucked up and thought I connected my 12v supply to the main board backwards. So I switched. Because the wires were not properly color coded I did have the power correct from the beginning and when I switched them I reversed the polarity and blew out the main board. With the help of Johannes and Daniel I was able to trouble shoot the board and get a bunch of stuff replaced. But I kept running into issues. Once I changed out a cap I was no longer able to communicate with the inverter via the computer. One of the Olimex boards went south and the processor on the board would get scorching hot. Lights blink but it finally gave up the smoke. The other Olimex board I have only shows I have power to the board but the green light will not blink.

So with all that I just decided to build my own main board as I did buy a kit. Figured that if I had one already built I could get to work straight away. Nope. So I finally got my main board finished tonight except three components I am waiting to get. Im waiting for an Olimex and two caps. Then I should be able to get back to work. So the main board is my second ever circuit board I have ever built. So with that, if I screwup I don't care. I am having a blast learning and playing with this inverter. I plan on trying this inverter with my AC-35 motor to see how well it will work. I'd like to see an AC-35 running 156 volts and 600 amps. Some day but for now its low voltage. 

After I finished my board this evening I picked up the USB CNT Serial Converter to put on the new board but saw a tiny copper wire where it should not be. I looked closer and found that the trace had burnt off and apart and the copper trace was hanging on one side. So that little sucker blew as well.

Well no wonder I lost communications to the computer and inverter. One problem after another makes it pretty much makes it impossible to fix but one bit at a time I will prevail. Im still going to try the board I fixed. I have a new Serial Converter so I will check which wire goes where then try this sucker again. 


I'll show more as I figure things out. If successful with the old board I will show that as well. 

The small driver board was my first ever circuit board and one component did not solder well and Im not confident that the hole is any good for replacement. I have plenty of extra empty driver boards to be populated. I plan on building a set using the chip that Jackbauer is using on his inverter project. He says the chip is better for larger IGBT modules. The main board is my first attempt at a large circuit board and all the connections are very good. Im getting much better at soldering. 

Pete


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## dcb (Dec 5, 2009)

when in doubt, measure with a VOM  

Oh, and dont forget to remove/disconnect pin 6 on the new chip (physically, not just unsoldered). the board connects pin 6-7 and the new chip connects pin 5-6, nothing good will come from shorting out the gate lead.

http://www.diyelectriccar.com/forums/showthread.php?p=547561#post547561


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## onegreenev (May 18, 2012)

Back to making headway again. I found the USB/Serial Converter had a blown ground trace. I replaced it and checked out the inverter and all looks good and the output voltages all look good even on all three drivers. I connected it up and found that I needed to swap two wires on the USB/Serial to allow it to talk to the computer again. Once that was done I found that I was now using Port 12 instead of 11 as before. Now Im talking to the inverter and computer. I can change parameters again. Johannes had me check the status of din_emcystop and I am still getting zero instead of 1. So something is amiss still. Time to check more wire output voltages. I hate those dinky little fragile ribbon cables. Just hate them. They do keep things looking tidy but they are sooooo flimsy. This needs more robust cables. Im looking into that. But for now its back to what we have. There are no open wires where there can be a short. Visible anyway. The main board is not able to short out from the back side. This is just odd. 

Anyway, wanted to keep the updates coming in. 

Pete


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## onegreenev (May 18, 2012)

Did an inverter parameter check. Here are the parameters as they were this afternoon. I have set the fweak and fslip and ampnom. The rest are pretty much default. Im going to try once again with my Mac running Windows. I had it running using that before. Maybe it will prove successful. 

Pete 

At least I can talk with the inverter again. 

Version 2.62
boost ———7500
fweak ———14.68
fslipmin ———1
fslipmax ———3
polepairs ——— 2
ampmin ——— 50
speedflt ——— 1
fmin ——— 1
fmax ——— 100.09
pwmfrq ——— 2
deadtime ——— 100
numimp ——— 64
potmin ——— 0
potmax ——— 4095
brknompedal ——— -50
brkmom ——— 30
brkmax ——— 30
brkrampstr ——— 10
udcsw ——— 12
udcmin ——— 12.09
udcmax ——— 120
udclim ——— 300
ocurlim ——— 100.37
minpulse ——— 1000
il1ofs ——— 1925
il2ofs ——— 1936
il1gain —— -4.68
il2gain ——— -4.68
udcgain ——— 3.50
tmpgain ——— 100
tmpofs ——— 65000.00
snshs ——— 0
snsm ——— 2
fslipspnt ——— 1
ampnom ——— 49.78


opmode ——— 0
udc ——— 0
idc ——— -0.09
fstat ——— 1
speed ——— 0
amp ——— 4781
pot ——— 0
potnom ——— 0
dir ——— 1
din_start ——— 1
din_mprot ——— 1
din_forward ——— 1
din_reverse ——— 0
din_emcystop ——— 0
din_ocur ——— 0
tm_meas ——— 13


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## onegreenev (May 18, 2012)

Got the Mac/PC to talk with the inverter again. No difference, still no motor movement. Guess I still need to get the new board finished. Waiting on parts to arrive. 

Pete


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## onegreenev (May 18, 2012)

Well, damn, I got the motor to run twice. Once on the desk top the next on the floor. I set a parameter but did not save the parameter and the motor started right up but I did not expect to see the motor run. It jumped off the desk onto the floor, Damn, I did not have my camera on. Then after the crash I checked that the motor was still OK and turned up the throttle again and it spun right up. I got the motor back up on the desk and secured it down. Then tried to start it again and it did nothing. Im thinking that one of the caps blew again for some reason. I can still talk to the inverter. I reset all parameters as I had them before the start and crash. So its time to check the caps.

Im taking a break and will return later to see. If its a cap blown I will have to wait a few days again until my spare parts arrive. 

Pete


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## Tomdb (Jan 28, 2013)

Which motor are you running? Is a encoder connected? 

Right now i am in the same fase as you are, took me quite some checking of my soldering to make sure all the voltages/switching were correct. Now im stuck with figuring out an encoder.

Running it in opmode 2 (start 2) or starting it via the start input on the inverter?


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## onegreenev (May 18, 2012)

Tomdb said:


> Which motor are you running? Is a encoder connected?
> 
> Right now i am in the same fase as you are, took me quite some checking of my soldering to make sure all the voltages/switching were correct. Now im stuck with figuring out an encoder.
> 
> Running it in opmode 2 (start 2) or starting it via the start input on the inverter?


I am running an AC induction motor from a forklift. It came from a Raymond Forklift. Its a pretty nice little motor. Im running the encoder thats built into the motor. It has a dual output encoder bearing. I have been running in mode 1. Never did get this sucker to run on start2 mode. 

The video is before I got it to run with the encoder. Now I'm having trouble again even after todays successful run and motor on the floor mishap. All my power is showing where it should be and just pulling out what little hair I have left. Arrg.


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## onegreenev (May 18, 2012)

Arrrg. Im done for a few days with this project until parts arrive. I had disconnected all the power including the USB power from the computer and inverter. I unplugged the ribbon cables and left the USB/Serial converter connected to the main board. It fell over and touched the metal base of the heat sink and let out a little puff of smoke. There must have been enough residual power in a cap somewhere because that would be the only source of power to short it out. It blew a small hole in the top of the processor and blew out the ground trace like the other one. Im now guessing that is what caused the problem of the other USB/Serial. So to anyone playing with these, put some shrink wrap around that sucker so if it falls it won't short out by accident. So all my components will be here in a couple days and then I will try again. Not sure what the deal was when the motor started twice then it quit. 

Pete


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## Duncan (Dec 8, 2008)

Hi Pete
I'm impressed!
As a mechanical engineer with no electronic knowledge I managed to build an OpenRevolt controller and I learned an absolute ton
But what you are doing is an order of magnitude more difficult


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## onegreenev (May 18, 2012)

Duncan said:


> Hi Pete
> I'm impressed!
> As a mechanical engineer with no electronic knowledge I managed to build an OpenRevolt controller and I learned an absolute ton
> But what you are doing is an order of magnitude more difficult


Thanks Duncan. 

Thats kinda how I like to do things. Jump right in and go for broke. I know the problem is a configuration problem. Its not a hardware problem. I know the inverter works. I know the motor works. Even after the motor took its dive off the table today it still worked before I pulled it back up on the table. Damn, I wish I had my camera running when that happened. It would have made for some great video. I do have an end goal in mind. Its not to just drive a car with it. But I think this will have great possibilities for the DIY guys. There are a few of us doing this inverter project that I now about. 

I'll be impressed when I get it going again. I'll be impressed if I can figure out the problem. Until then its a great puzzle to keep the ol noggin going. 

Pete


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## onegreenev (May 18, 2012)

New main processor board finished. I got my replacement parts and some extra so I could finish the new main board. The old board is still good. Waiting now for the USB/Serial device so I can talk to the controller. I have some new parameters to plug in and the motor should be secure enough to not take a dive off the table next time it runs up. Hoping to get some video feed this weekend.


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## onegreenev (May 18, 2012)

Got my USB/Serial devices and I connected up the main board and found that the IC5 might be a wrong one. There are two types available. One with a fixed output and the other an adjustable output. Mine is only putting out 1.2 volts when I need 5 volts. There is a way to change the output voltage via resistors but I will need help on that. I have contacted Johannes to ask about some specifics. Darn. I wanted so bad to play with this tonight. 

Bummer. 

Pete 

My old board is doing some funky things too but my checks on the board still show all is fine. Strange. 

I'll check more and see if we can get around this and get moving forward again.


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## onegreenev (May 18, 2012)

New IC5 modules on the way. Should be here by the weekend. Until then, the garden gets planted. Its huge. Will take a few days to finish.


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## onegreenev (May 18, 2012)

I was doing some further troubleshooting on my inverter board. I decided to test the capacitors again. The capacitor that goes to C20 on the board was not showing good. I decided to take that cap off then put on a new one. Interesting, that one tests bad too. I then took a cap that was not connected and tested the new cap and it worked just fine. Arr..Damn, did I screwup another cap. Can't imagine how. Well, my son was over doing some trouble shooting on my Diesel Truck and he was in the room when I was testing. He said, check the one you pulled out. So I did. Well what do you know, it works just fine. The cap on my new board works fine too. So there is something on the one inverter board that is causing the cap to test bad. So I figure there must be a short or drain that won't let me test the cap properly. It will always show bad when connected but good off the board. Now to track down the problem. I'd like the original board to work properly again. Maybe this problem is why I have problems with my Olimex board and why I can get things running sometimes and not others. My IC5 regulators did not show up today. Im expecting them tomorrow. Then I will fire up my new board once I get one installed. 

Pete


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## jhuebner (Apr 30, 2010)

Maybe its a pointer. But it's not unusual that measuring devices in-circuit gives wrong results. You're measuring everything in parallel after all.


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## onegreenev (May 18, 2012)

So today the proper IC5 regulator. This time its the fixed voltage of 5v output. I checked all my caps and connections again and the cap in position C20 checks fine. I still can't get that one to test fine with the original board. So now its another waiting game for the programmer for the Olimex boards. Johannes helped there so with the proper programmer I will be able to load up the software needed and when there is an update I can just plug in the updated software without having to wait for an updated board to be shipped. Im getting a few spares. I love messing with this stuff. Learning a load of things. Even with all the snafu's Im still quite positive about this. 

Im going to check the components on the original board to see if I can track down any problem. If not and the board is still good then that will be good but can't wrap my head around one board where the cap checks good and the other it does not. Strange stuff. 

Pete


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## onegreenev (May 18, 2012)

Got my JTAG programmer. All I need is to load a program. I don't need a development environment. Just a flash loader that will flash the STM32 h103 Olimex board. But getting that working has been just a mess. I have tried many things but nothing that would send the files to the onboard chip for flashing. Once I have my Olimex flashed I can get back to playing with the inverter. Johannes is sending me two that are flashed and I have two that need flashed. I'd like to find a way to flash these so if there ever is a need to flash an update I can do so on my own setup. I use a Mac with Windows 7 and Ubuntu installed. I have an Olimex ARM JTAG programmer with cable to connect to the Olimex board.


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## sdev (May 3, 2015)

Hi

I have been following this with great interest. Can I ask you, why four caps and what value are they. In other words how do you calculate the amount of necessary capacitance. ??
Sdev


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## generatorlabs (May 31, 2014)

@onegreenev: Hey, I totally did not know what progress you made with the controller. I know when you bought the controller from me you were dealing with some medical issues and I figured it would be a while before you got back on your feet. I have not been on this board since I took possession of my BMWi3. That was almost 3 years ago! The i3 has been a joy to own.

I was pleasantly surprised to see your video of the motor spinning! And equally surprised of the honorable mention in the video. Thanks! ( I am in South Carolina not North Carolina) I too had that motor move on the table from some silly parameters I entered into the controller! I was scary to see that thing take off! I wish I would have lived closer, I would have certainly helped you get your rig running sooner.

@sdev: The caps were chosen based on discussions I had with jhuebner and also based on some of the videos I watched by Damien Maguire on youtube. There was no scientific method on my behalf. I just made sure the caps were rated well beyond the expected operating voltage. The caps are sized large to provide a good bank of instantaneous energy and a decent amount of filtering. Large caps are rather expensive. In this case I found old new-stock at a reduced cost. The snubber caps were sized according to recommendations from jhuebner. This is what I can recall from memory as it was over three years ago when I started testing the controller.


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