# Re: [EVDL] High voltage systems



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Metric Mind wrote:
> > EVDL Administrator wrote:
> >
> >> I think voltages in the 300-400 range are likely, indeed already exist, but
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> henry buehler wrote:
> > Trying to come up with a concept without any idea what I am talking
> > about. A one cell battery connected to a coil for a timed pulse of
> > electrical power for an AC motor. Three phase AC is it a full sine
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Ryan Stotts wrote:
> > How about high power and high current?
> > Is there anything available on the AC side that offers 640,000 Watts or more?
> > Can the AC motors take that kind of power and more?
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

> Try this: Get an old car alternator; it is really a 3-phase AC
> synchronous motor. Take it apart, and bring out the 3 wires from the
> coils that normally go to the internal diodes. Also find the field
> coil connections to the two slip rings.
>
> Wire up six regular 120vac light switches to the 3 coils like this
> (view with a fixed width font).
>
> _ _ _
> +12V__| | | |_____________________________
> rotor | | |
> field | S1 / |
> coil | |_____ |
> | | | |
> | S2 / |_ |
> | | _| stator |
> | GND _| "A" |
> | _| coil |
> S3 / _ _ _ | _ _ _ / S5
> |___| | | |__|___| | | |___|
> | stator stator |
> S4 / "B" "C" / S6
> | coil coil |
> GND GND
>
> The six switches S1-S6 do what electronic switches (transistors,
> MOSFETs, IGBTs, etc.) do in an AC controller. By experimenting, you'll
> find that:
>
> 1. With all the switches off, no current flows, and the alternator
> can be spun by hand freely.
>
> 2. If you close one upper switch and its matching lower switch
> (S1+S2, or S3+S4, or S5+S6), then current flows through the field
> coil, but not through any stator coils. The alternator can still
> be spun freely by hand.
>
> But, put a meter between any two of the stator coils (A-B, B-C,
> or C-A). You'll find that it is acting as a generator; when you
> turn the alternator, an AC voltage is generated on each coil.
>
> 3. If you close *two* pairs of switch (S1+S2 and S3+S4, for example),
> current flows in the field *and* you have shorted one of the stator
> coils. Now the alternator gets harder to rotate by hand, and you
> don't have a voltage generated on the the stator windings (because
> they are shorted).
>
> 4. Now the tricky part. If you operate the switches in just the right
> sequence, the alternator turns as a motor. Try this sequence:
>
> S1 S2 S3 S4 S5 S6
> -- -- -- -- -- --
> 1. on on on
> 2. on on on
> 3. on on on
> 4. on on on
> 5. on on on
> 6. on on on
>

I think this is similar to the"six step" drive which has off times also.
If we turn this table on it's side and look at 6-step from the coil's
perspective, you can see the offset sign waves hidden in it.
point X is between S1 and S2
point Y is between S3 and S4
point Z is between S5 and S6

When S1 is closed and S4 or S6 is closed, the current flows from 12V
thru the coil
When S2 is closed and S3 or S5 is closed, the current flows the other
direction in the same coil
step|__1__|__2__|__3__|__4__|__5__|__6__|
___________
A | |_____ _____
|___________|
___________
B ______| |_____
|___________|
____________
C _____| |_____
|___________|

The inductance of the motor helps integrate the rough 6step into a
smoother sine wave.
The off times help make the controller easy, you can sense current in
those off phases and avoid shoot through.

> When you get to step 6, repeat step 1. The alternator should
> turn a little bit with each step. If you keep it up for several
> cycles 1-6, the alternator will make a complete revolution.
>
> This is how a "stepper motor" works. You find them in clocksm where
> you can see each step as the second hand moves in jerks.
>
> A series DC motor replaces the switches with a mechanical rotary
> switch, called the commutator. This switch is linked to the motor's
> shaft, so it automatically rotates to the next step as the motor turns.
After looking, Although we call a series motor that becasue it's field
is in series, I really think the series motor,as we know it, is a unique
beast. While a commutator could be made to memic the 6 switches, it is
the sliding under a brush that changes the relative current direction of
a coil and thus it's polarity. A sneaky trick. I suppose we could
consider the slideing under the brush as the transition from S1 closed
to both open to S2 closed occurring at each brush. The we could call the
14 or so coils between each brush in series coil A. As it moves past the
brush it becomes reversed polarity coil A and as it reaches the next
brush it magically becomes coil B. I guess this is semantics since the
filed is stationary and the coils are rotating.

> A shunt or sepex (separately excited) DC motor is the same thing, but
> the field is wired in parallel (shunts across) the switches and their
> coils.
>
> A PM (Permanent Magnet) DC motor replaces the field with a magnet.
>
> An AC motor has an inverter to operate six electronic switches in the
> right sequence. Again, the field can be series, shunt or PM. If PM,
> it's called a "brushless DC" motor.
>
> For an induction AC motor, you short the field winding, and depend on
> transformer coupling from the three phase windings to power it.
>
> I built such a setup as my first hands-on demo of how motors work. I
> then replaced the mechanical switches with transistors, operated by an
> old 4-channel stereo amplifier, so I could easily control the
> waveforms to the switches.
>
> If you do this, you'll find that sinewaves, square waves, triangle
> waves, and just about any waveform you can think of can make the motor
> run. It just works better with some waveforms than others. The
> construction of the motor affects what waveforms it prefers.
I was told that hooking up an oscilliscope to a motor and giving it a
spin (after a pulse of excitation) can graph for you the BEMF signature
and what would drive it best. I read some documentation on coil loading
and rotor construction and how it relates to the this driveing waveform.

The difference between the 6 step and the other drive is how you PWM the
lower transistors.(or top, usually only need to PWM 1/2 of them)
If you PWM the duty in relation to the amount of load only, and
commutate the top half, you have 6-step.
If you have shaft position accurate enough and can pwm in relation to
how many degress it is in each quadrant also , then you can get a near
perfect sine wave.
> -- 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

----- Original Message ----
From: Dan Frederiksen <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Sunday, January 27, 2008 3:13:06 PM
Subject: Re: [EVDL] High voltage systems



> Ryan Stotts wrote:
> > How about high power and high current?
> > Is there anything available on the AC side that offers 640,000 Watts or more?
> > Can the AC motors take that kind of power and more?
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Lee Hart wrote:
> >> Get an old car alternator; it is really a 3-phase AC motor...
> 
> From: Jeff Shanab <[email protected]>
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

From: henry buehler <[email protected]>
> Trying to come up with a concept without any idea what I am talking
> about... It's like you are both encouraging the concept, I'm not sure
> it is technically feasible or physically possible.

We're trying to provide a basic explanation of how normal motors work, so you can understand them, and better describe what you have in mind.

> The idea was to have the best possible realtime observation of the
> condition of each individual cell, the best way to prevent damage to
> any individual cell.

Most setups have a single power source, and lots of coils and switches that get connected to it in various ways. But it would be possible to turn this around, and have lots of cells that get connected in various ways. Once you understand one, you can replace coils with cells and cells with coil to get some idea where it will lead.

The only thing new is the history you don't know yet. -- Harry Truman
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> ROBERT RICE wrote:
> > 600 plus voltage. Not much demand yet, for these voltages? But do you REALLY want to mess around with this stuff? It CAN be lethal
> 
> yes but I imagine 350V isn't a picnic either. has anyone here ever been
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> ROBERT RICE <[email protected]> wrote:
> > OK Guyz, yur getting up in to the magic realm of Light rail; Rail cars and Trakless trolleys go for, and with 600 plus voltage. Not much demand yet, for these voltages? But do you REALLY want to mess around with this stuff? It CAN be leathal
> 
> 72 volts can be lethal; most EV battery packs could kill you.
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

You get into the right range and someone is already making what you need....

http://www.samincoinc.com/
_____________________________________________________________
Begin a career in graphic design. Click here for free information.
http://thirdpartyoffers.netzero.net/TGL2221/fc/Ioyw6i4s5wZBRvssLv7jldCVTbSPLy5WUlhM3HJPGm1yDPPAXogeD9/



_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

High-performance EV systems are headed towards 800 volts. I think 
this is about the highest you will see in a car, at least for the 
foreseeable future.

When you look at the available contactors, fuses, wiring insulation, 
capacitors, and IGBTs, 800 volts is about the top of the "ordinary" 
components. Once you go much higher, corona becomes an issue (the air 
starts to ionize if you aren't careful at/near terminations.) Thus, 
this is probably the sensible maximum voltage to use in an ordinary 
car-sized EV. (Trains routinely go to 13,000 volts, but they are 
really big and don't run on batteries.)

Bill Dube'

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Bob Rice wrote:
> >> OK Guyz, yur getting up in to the magic realm of Light rail; Rail
> >> cars and Trakless trolleys go for, and with 600 plus voltage. Not
> >> much demand yet, for these voltages? But do you REALLY want to mess
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Morgan LaMoore wrote:
> > Interesting. You'd need 600V IGBT's for a 300V battery, so why not use
> > a 450V pack instead with the same transistors?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Lee Hart <[email protected]> wrote:
> > 600v IGBTs aren't really good for switching 600v. First, this leaves no
> > margin of error for transients. Second, you'd find that the switching
> > losses are excessive unless you switched them at much lower speeds.
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

From: Morgan LaMoore
> I wasn't suggesting switching them at 600V; I was suggesting 450V,
> which still leaves a very large margin of error.

OK; though I'm not sure that 600v IGBTs would be enough for a 450vdc supply. I've had them die in a 400v boost converter, for example.

> Just 200 microfarads of 600V film capacitors would ensure that you
> use less than 1/3 of your margin of error, even at 500A current draws.

Probably so; though 200uF of film caps is quite a bundle!

> I definitely see what you mean about switching losses going way up,
> though. Whenever I've run calculations, I've found that conduction
> losses far exceed switching losses, though.

The designs I've seen seem to run the switching frequency as high as possible to avoid acoustic noise. When they do that with IGBTs, it means switching losses can actually exceed conduction losses. Since switching losses go up roughly as the square of the voltage, very high voltages can cause very high switching losses (unless you lower the frequency).

> It seems like reducing conduction losses (by reducing currents) would
> be worth the increase in switching losses.

Yes, when you can increase the voltage. I was thinking of the consequences of someone who changes from 600v to 1200v IGBTs at the *same* voltage to avoid cleaning up the transients. This won't help, because the higher voltage IGBTs will have higher conduction losses (at the same pack voltage).

The only thing new is the history you don't know yet. -- Harry Truman
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

Will Thyristors ever likely show up in EV's?

http://en.wikipedia.org/wiki/Thyristor

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

Thyristors are old school. My old Cableform 800 amp rattling controller had 
them. Replace it with a Zilla.

Roland


----- Original Message ----- 
From: "Ryan Stotts" <[email protected]>
To: "Lee Hart" <[email protected]>; "Electric Vehicle Discussion List" 
<[email protected]>
Sent: Monday, January 28, 2008 4:55 PM
Subject: Re: [EVDL] High voltage systems


> Will Thyristors ever likely show up in EV's?
>
> http://en.wikipedia.org/wiki/Thyristor
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Ryan Stotts wrote:
> > Metric Mind wrote:
> z>
> >> For high power and low current (<300 battery amps)
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Metric Mind wrote:
> 
> > What I find interesting in all your posts, they all (practically
> > without exception) end with question mark, and mostly about power.
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

You need to think in terms of wattage on the switch. It is the amps 
times the volts. (For the same HP drive, the amps are half as much 
when you double the system voltage.) The voltage drop on the switch 
only goes up by a factor of 2.5/1.7 = 1.47. Thus, the efficiency is 
about 36% better just considering the "on" state under full load.

The switching transient losses are another issue that you have 
ignored, however. These are often the major losses in a "silent" inverter.


> > As the voltage rating goes up, the on-state voltage drop also goes up.
> > This lowers your efficiency.
>
>Looking at datasheets, it seems like a common on-state voltage drop
>for 600V IGBT's is 1.7V, while 1200V IGBT's are readily available with
>an on-state voltage drop of 2.5V. If you compare a 400V battery system
>with 600V IGBT's to a 800V battery system with 1200V IGBT's, the 400V
>system will see 1.7/400=.425% of the battery voltage drop across the
>transistor, while the 800V system will see .313% of the battery
>voltage drop across the transistor. This means that the conduction
>efficiency of the high voltage system will be higher.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Bill Dube <[email protected]> wrote:
> > You need to think in terms of wattage on the switch. It is the amps
> > times the volts. (For the same HP drive, the amps are half as much
> > when you double the system voltage.) The voltage drop on the switch
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Bill Dube wrote:
> >> You need to think in terms of wattage on the switch. It is the amps
> >> times the volts.
> 
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

Please excuse the pun but higher voltages have more potential to cause
damage. 
Your body is a resistor the current it will conduct is based on ohms law.

1K to 10K (depends on moisture and arc length)


The amperage burns and the voltage disrupts nervous system.
AC gives you zero 2 crossing points per cycle, a chance to break contact
and extinguish an arc, the DC holds on.
In an EV we are talking about combining all three in one location.




_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Metric Mind wrote:
> > Is there anything available on the AC side that offers 640,000 Watts or more?
> >
> >> Can the AC motors take that kind of power and more?
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

High voltage systems seem to be getting a lot of attention, but there's
always the flip side...

What hurdles might one need to overcome in making an electric vehicle that
ran on a 12 volt pack?

Are 12 volt controllers available that can output more than 600 Amps? How
about batteries? I assume you would you need to have several in parallel...

At 12 volts, I figure that a scooter might need 300 Amps, a motorcycle could
use 600 Amps and a light car maybe 2,000 Amps.

Lots of 4/0 gauge wire. Perhaps dual motors and controllers. But couldn't
it be done? What would be the advantages and disadvantages?

I can think of one advantage. You wouldn't need a DC/DC converter...

Bruce



> Lee Hart wrote:
> > For a given amount of power, it generally works out best to have the
> > voltage and current roughly equal. Thus we have ebikes at 12v and 15a,
> > golf carts at 36v and 75a; VW Rabbit EVs at 96v and 100a; and the GM EV1
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

Another option...rather than doubling the size and voltage/current, how about just using more motors and dividing the load,,,I seem to recall a certain streamliner catching the land speed record this way...

http://www.dwra.net/motors.htm

How fast can your mustang go now?
_____________________________________________________________
Need cash? Click to get a cash advance.
http://thirdpartyoffers.netzero.net/TGL2221/fc/Ioyw6i4tF3DY8peTPJ2ZD2X6qwTJsAMD25REVcdJZ6dx0kkhWofYVR/



_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Ryan Stotts wrote:
> > Metric Mind wrote:
> >
> > I've got a turbocharged Mustang and if I convert it to electric; it's
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

I was doing some calculations a while ago when I wanted to design an AC
drive. It appeared as if switching losses can be reduced by switching
from sinusoidal drive to 6 step at higher rpm and keeping the sinusoidal
drive for lower rpm where it is smoother and more efficient.

The sensorless 6 step drive would be the redundant fall back mode
when/if the encoder fails
This also would reduce the processing power needed, kinda like auto
manufacturers currently do with car computers, and might help keep the
cost down. At least that was my hope. Perhaps reprogram fuel injection
computers in existing cars, the 6 fuel injector drives drive the IGBT's 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

>Even with a 6-step square wave, you need to control the amplitude,
>which requires PWM (and switching losses). So you might as well use
>sinusoidal commutation when a $10 micro has all the processing power
>you need to do sinusoidal at 20kHz (using lookup tables).

Depends on what the motor wants, too. Some motors won't like the
harmonics of a square wave, and some are wound for it.

>I think a modern gas engine requires more processing power than vector
>control of AC Induction motors.

Modern gas engines do, however, the priorities are a lot different.
The I/O is typically a lot slower and less precise (there are filters
on all of the inputs that you don't necessarily want). An IC engine
has a bandwidth of maybe 100 Hz. Some sensors are sampled more like
1000 Hz. The exception is engine speed and position, which is usually
a 6 crank degree pulse (with two teeth missing). About 60% of the
software in a modern ICE controller is dedicated to diagnostics. A
typical 'semi-modern' controller (2002-2006) is based on the Freescale
MPC563 and MPC565.

I'm not so sure that the best idea would be to use an automotive ICE
controller to make an EV controller out of. Also, a lot of hassle goes
into getting past the bootloader security and stuff like that. Also,
the injector driver outputs don't need to have matched propagation
delays, it is common for automotive ECM's to have somewhere between
2 and 50 microsecond delays on the injector outputs with a wide
tolerance. You don't want that on a VFD bridge because it'll blow up.

I think that a DIY controller would be nice with one of those
DSPIC30F parts, CAN bus, and then another controller to actually
do the torque mapping. Leave the VFD DSP/controller to do vector
control, fault finding and management, and just communicate
that information back and forth to another controller via a CAN
bus. I've got PC boards done up for this (DSPIC, isolated CAN,
isolated gate drives, power supply) but I haven't got around
to getting them made up yet. I was trying to figure out how to
do phase current sensing so I was planning on allowing either
voltage drop sensing or LEM (0-5V) inputs.

For either a BLDC or ACIM, a lost-sensor fallback might as well be
whatever the motor wants (sinusoidal or six-step), you just need
to estimate rotor speed and position which you can do with or
without the speed sensor.

Maybe use an automotive-style speed sensor like the Siemens motors?
Fine-pitch encoders are a PITA and seem to be a reliability problem
whenever I talk to anyone using them.

-Dale

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Dale Ulan wrote:
> 
> > Maybe use an automotive-style speed sensor like the Siemens motors?
> > Fine-pitch encoders are a PITA and seem to be a reliability problem
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

>Perhaps sensing implementation of people you talk to has dome design
>deficiency.

The guys I talk to doing VFD's are usually doing it for oilfield
applications
up here (I'm in Alberta, Canada, where oil is pretty big business). Anyways,
many of these industrial VFD's use little industrial encoders that seem to
have a lot of bearing problems. The Siemens motor design appears to be very
good, in my opinion - very similar in design to the 60-2 wheel used in most
automobiles these days. Those are robust, and in my mind, the Siemens ones
should be, too.

I have a pair of Solectria BLDC's with hall effect sensors, and I'm not
too crazy about the reliability of them. A slight overspeed and the magnet
flies apart, then the controller screws up - it's all simple logic, no
brains - and the motor commutates wrong, then the controller blows up,
and the motor stops very rapidly.

-Dale

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Metric Mind wrote:
> 
> > 'Course I got motor. Which one are you talking about?
> > So, which motor do you want Ryan? I'm an engineer, so
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Ryan Stotts wrote:
> > Think about the 8" and 9" ADC and WarP motors. Consider their price
> > and their availability. We need something like that in an AC flavor.
> > Relatively low cost and plentiful and suited to EV use. Something
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

> We've got what now?? Otmar said "don't hold your breath," not "ready to go."


Scroll down to the "Insight EV"

http://cafeelectric.com/other.php

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Ryan Stotts wrote:
> >> We've got what now?? Otmar said "don't hold your breath," not "ready to go."
> >>
> >
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Ryan Stotts wrote:
> 
> > Think about the 8" and 9" ADC and WarP motors. Consider
> > their price and their availability. We need something like
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Ryan Stotts wrote:
> > Scroll down to the "Insight EV"
> >
> > http://cafeelectric.com/other.php
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Roger Stockton wrote:
> > But, let's assume for a moment that we do. A Z1K runs about $2k, so
> > it stands to reason that a tri-Zilla would run about $6k, perhaps $5k
> > assuming some savings in packaging, etc.
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Rick Beebe wrote:
> >
> > What is it about AC that makes everything so expensive? Why does it
> > stand to reason that a tri-Zilla has to be $6k and not $3k?
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Rick Beebe <[email protected]> wrote:
> > What is it about AC that makes everything so expensive? Why does it
> > stand to reason that a tri-Zilla has to be $6k and not $3k?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Dan Frederiksen wrote:
> >
> > anyone know what that is?
> > http://cafeelectric.com/insight/Conversion/InsightTemp-Pages/Image20.html
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Rick Beebe wrote:
> > What is it about AC that makes everything so expensive? Why does it
> > stand to reason that a tri-Zilla has to be $6k and not $3k?
> >
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

> A DC motor only needs one chopper. An AC motor needs three choppers.

Don't forget that the DC controller's single phase only needs to sink
current, whereas the AC controller's phases each need to alternately source
and sink current. So the three AC output stages are typically totem poles.
Hmmm, make that 6x the power electronics.

Steve W


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Jeff Shanab wrote:
> > I was doing some calculations a while ago when I wanted to design an AC
> > drive. It appeared as if switching losses can be reduced by switching
> > from sinusoidal drive to 6 step at higher rpm and keeping the sinusoidal
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Morgan LaMoore wrote:
> > Even with a 6-step square wave, you need to control the amplitude,
> > which requires PWM (and switching losses).
> 
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> [email protected] wrote:
> > Another option...rather than doubling the size and voltage/current,
> > how about just using more motors and dividing the load,,,I seem to
> > recall a certain streamliner catching the land speed record this
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Rick Beebe wrote:
> > Roger Stockton wrote:
> >
> >> Why would it be reasonable to expect an AC motor suited for on-road
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

You can due less and simpler PWM for the 6 step

the ac vector drive needs an order of magnitude more processing power.
look up tables help reduce the work.
The modern car computer, circa 2001 for example, is not that powerful.
GM standardized on the Motorola processor and if you look at the code
you will see that they do a lot of nifty tricks to get by on this
limited power. obviously the processing power goes up every year and I
hear they are on powerPC cores now.

They use a single formula that overwrites a value(called the Block Learn
Value) This value is then added to the value in a lookup table to offset it.
There are 3 tables one for spark, one for fuel PWM and one for timing.
While this sounds terribley off topic, I have a point. A V6 firing 6
fuel injectors every 2 rpm, 3 pulses per rpm? in one rpm of a 3phase
4pole motor, each commutating transistor turns on twice, so that alone
is 6 pulses. Not bad and shows how probably a ECM could do 6-step up to
about 6000 rpm. I have a 2001 malibu ECM here that I got to try this and
see how fast it could spin a motor using the fuel injector drives to
fire IGBT's

For the sine wave part of the drive we set the pwm of the bottom
transistor to a value in the look up table based on the rotor position
within the pulse for that phase. Even with a lookup table this is at
least 10X faster for reasonable results.

Now double everything I just said to get to 12000 rpm to keep the AC
motor size down.
Now add the real-time calculations needed to compensated for inertial
loads and get the most power at low speeds without melting down the
rotor and we can easily see a need for 10x more.

With 6-step a PWM freq is chosen to give you that voltage regulation, a
slow micro can have a fast PWM freq if it is just an output and not
being used to construct the shape of the sine wave. The same circuit can
do both, just do the sine when the processor,feedback, and drive
circuitry can keep up and the 6 step at higher rpms.

This is just an "on-paper" concept at the moment.It may be that
processors have drooped so much that even making 30K cars a year this is
a non-issue. but man that siemans or AC propulsion box is huge.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Stephen West wrote:
> >> A DC motor only needs one chopper. An AC motor needs three choppers.
> >
> > Don't forget that the DC controller's single phase only needs to sink
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Morgan LaMoore wrote:
> > Microchip PIC30F microcontrollers were designed specifically for motor
> > control; application notes are available for controlling all sorts of
> > motors, including full vector flux control of AC induction motors.
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Dan Frederiksen wrote:
> > anyone know what that is?
> > http://cafeelectric.com/insight/Conversion/InsightTemp-Pages/Image20.html
> 
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Rick Beebe wrote:
> 
> > What is it about AC that makes everything so expensive? Why
> > does it stand to reason that a tri-Zilla has to be $6k and not $3k?
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Bruce wrote:
> > What hurdles might one need to overcome in making an electric vehicle
> > that ran on a 12 volt pack?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Lee Hart wrote:
> 
> > Plain old 6-step inverters are so simple that you don't even need a
> > computer for one; cheap old gates and flip-flops are enough. They can
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Jeff Shanab wrote:
> ...
> > This is just an "on-paper" concept at the moment.It may be that
> > processors have drooped so much that even making 30K cars a year this is
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Morgan LaMoore wrote:
> > Microchip PIC30F microcontrollers were designed specifically for motor
> > control; application notes are available for controlling all sorts of
> > motors, including full vector flux control of AC induction motors.
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

Zeke Yewdall wrote:
>


> Ryan Stotts <[email protected]> wrote:
> >
> >> How about high power and high current?
> >> Is there anything available on the AC side that offers 640,000 Watts or more?
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

Could a WarP or ADC housing be converted to an AC motor if one was to
swap out it's guts with a custom wound rotor?

Anyone been to Advanceds site lately? Seems they have AC motors now?

http://www.adcmotors.com/products/

What are the specs and price on an 11" AC motor?

Victor, you got your ears on? 

Hey Ot, have we found the motor?

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Morgan LaMoore wrote:
> >> Microchip PIC30F microcontrollers were designed specifically for
> >> motor control; application notes are available for controlling all
> >> sorts of motors, including full vector flux control of AC induction
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

Has anyone looked at Don Lancaster's "magic sinewaves"?
http://www.tinaja.com/magsn01.asp
Basically PWM with very precise timings to eliminate low end harmonics.

Robert



> Morgan LaMoore wrote:
> > Even with a 6-step square wave, you need to control the amplitude,
> > which requires PWM (and switching losses). So you might as well use
> > sinusoidal commutation when a $10 micro has all the processing power
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

It doesn't automatically cost 3 times as much.
The power silicone is the single largest cost, but instead of 1000Amps
worth in parallel, you are gonna have them split out into phases for the
same overall power rating.
count on 2X in the power silicon section. one for foward and one for
backward direction on each coil. The duty cycle of each can be slightly
reduced so maybe less than 2X. Maybe we can assume higher voltage and
less amps, and perhaps we are back down to 1.5X on the silicon.

Now count on 50% more drive circuitry cost and additional sensor cost,
but they are a smaller percentage.

I am guessing we will see 2X price to start.


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

This may not appear at first to be EV related, but keep an open mind you'll see the relation....




> >> Metric Mind wrote:
> >>
> 
> >
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*

Tim,

The problem is that people are stupid. They don't think things 
through. I could go buy that nice shiny new 10k motor or I could go 
buy that used 120000 mile one over there for 1k or I could pull a 
total junk one from the wrecking yard for lets say 200. Now if you 
really think about it you should not buy that new 10k motor. Leave 
that for the manufacturer to install into the nice shiny new car. 
Since I can't afford the 10k motor and car I must now get what I can 
afford. Here comes the problem. Now what should I do. Duh! why that 
200 dollar wrecking yard special of course. Now it get it home and 
tear it apart and find it needs a crand, rods, pistons, lifters, 
heads, cam and all that stuff. So dumb me goes to the local machine 
shop to have the block checked out while I go pick up the parts at 
Kragen (walmart of auto parts) for super bloated prices. I used to 
work at an auto parts supply and know that prices are jacked 400 
percent from wholesale. How does that grab ya. Do you realize how 
cheap these items really are to make. We should all be living like 
kings if we were able to purchase good new after market parts for the 
real cost plus lets say 20 percent.


It is all political and about power and money only. Nothing else. If 
you come in and upset the status quo then you are in grave danger or 
your product is on the list to be bought out and shelved. Period.

Not EV related but has bearing on all aspects of life in general. Now 
it really sucks.

: )




> Tim Humphrey wrote:
> 
> >> After all its just a chunk of metal
> >> with some wire in it, what can be so complicated?
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Ryan Stotts wrote:
> Lee Hart wrote:
> >> Plain old 6-step inverters are so simple that you don't even need a
> >> computer for one; cheap old gates and flip-flops are enough. They can
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Jeff Shanab wrote:
> > It doesn't automatically cost 3 times as much.
> > The power silicone is the single largest cost
> 
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> Tim Humphrey wrote:
> > This may not appear at first to be EV related, but keep an open mind you'll see the relation....
> >
> >>> Metric Mind wrote:When I offer $10k motors about the best EV industry has to offer,
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] High voltage systems*



> On 29 Jan 2008 at 12:50, Dale Ulan wrote:
> 
> > I have a pair of Solectria BLDC's with hall effect sensors, and I'm not
> > too crazy about the reliability of them. A slight overspeed and the magnet
> ...


----------

