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EV conversion using Prius Transaxle

91K views 130 replies 22 participants last post by  asimor 
#1 ·
I acquired a 2001 Prius transaxle for $0 some time ago. I finally got some time to work on it. I completely took it apart and can’t find anything wrong with it. I don’t know what error code it produced to make the transmission shop swap it out.



I got both electric motors (MG1 and MG2) spinning using a Zilog Motor Control eval board that I already had and an Analog Devices Resolver to Digital eval board that I bought. The commutation software and resolver decoding was a little tricky but I got it working. With this success I am pretty sure that I can design and build my own control board with enough trial and error. I only used a 24V 3A supply which was fine for proof of control but at 24Volts my car would only go about 3 mph.


I just ordered a 2002 prius high voltage inverter ($100) that I want to hack into. I should be getting it in about a week. I am thinking that this will be easier and cheaper than me building my own. It has a voltage boost circuit, inverters for each motor with hall current sensors, etc. Even if it doesn’t work I should learn more from taking it apart and reverse engineering it than it cost me.



I learned that MG1 spins a few times faster than MG2 at the same voltage. This was expected, MG2 is the bigger of the two. MG1 and MG2 are connected to each other via a planetary gearset. MG2 drives the ring gear which is connected to the axle differential gearset at a 4.1 to 1 reduction. I have seen MG2 referred to as the traction motor. MG1 drives the sun gear and the planet carrier protrudes on a shaft where the ICE would connect if I had one.



I have a plan on how I want to configure the drive system that I haven’t quite seen yet so I thought I should get some feedback. I have seen where someone welded the planet gears rigid which allowed MG1 torque to add to MG2 torque driving the wheels.

My plan is to add a disc brake or clutch plate to the planet carrier output shaft where the ICE connected. By holding the shaft stationary and driving MG1 in the opposite direction of MG2 I should be able to produce a wheel torque of ( 4.1 X ( MG2 +( 3 X MG1))). I am trying to preserve the torque multiplying of MG1 through the planetary gear during low speeds. If this is correct I should be able to accelerate very quickly. At around 40mph, MG1 will be spinning at it’s max speed and I will release the brake holding the planet carrier. This should allow me to continue to accelerate using MG2 only driving the ring gear and to cruise. I will then set the MG1 speed to whatever speed is appropriate to drive the planet carrier shaft which is connected to the oil pump and to any other pump system (ie air conditioning) that I might attach to it. This configuration would also allow me the option of still using MG1 coupled with a small ICE to charge my batteries while the car is parked if needed.

My question is whether or not I am correct in my assumption about transferring MG1 torque to the wheels in this configuration and preserving the torque multiplying of MG1? Any recommendations experience on other configurations using this transaxle is welcomed?

Has anyone already made their own control unit for the prius inverter or have any wiring documentation?

Thank you
Jeff
 
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#3 ·
I have a plan on how I want to configure the drive system that I haven’t quite seen yet so I thought I should get some feedback.

Sounds interesting. I've mused over this a bit.

My plan is to add a disc brake or clutch plate to the planet carrier output shaft where the ICE connected. By holding the shaft stationary and driving MG1 in the opposite direction of MG2 I should be able to produce a wheel torque of ( 4.1 X ( MG2 +( 3 X MG1))).
That would appear right to me, from the equations I've seen, except that the 3 is actually 2.6 according to a web site I checked. (That's for the Generation II prius; the Gen I may be different).

However, these things are easy to get wrong, and I'm suspicious since MG2 is supposed to be the "torque" motor and MG1 is supposed to be the "speed" motor. But maybe that's only because MG1 can add to the speed of the ICE (by spinning backwards).

With the speed reduction (and therefore torque multiplication) of 2.6, the 10,000 RPM maximum of MG1 would run out at about 3800 RPM (at MG2), which is about 64 mph (Gen II). If MG1 is limited to 6500 RPM (as it is by default when the ICE is not running), then this limit becomes 2500 RPM at MG2, or 42 mph.

I am trying to preserve the torque multiplying of MG1 through the planetary gear during low speeds. If this is correct I should be able to accelerate very quickly. At around 40mph, MG1 will be spinning at its max speed and I will release the brake holding the planet carrier. This should allow me to continue to accelerate using MG2 only driving the ring gear and to cruise. I will then set the MG1 speed to whatever speed is appropriate to drive the planet carrier shaft which is connected to the oil pump and to any other pump system (ie air conditioning) that I might attach to it.
Interesting. One problem is that you would not have air conditioning or other mechanical loads running during low speed operation (or if you did, you'd miss out on most (?) of MG1's additional torque).

To do this with the existing Prius inverter, you'd probably have to have a 500 VDC pack (Gen II; 273 V for Gen I) to bypass the 20 kW limit of the DC-DC boost converter.

This configuration would also allow me the option of still using MG1 coupled with a small ICE to charge my batteries while the car is parked if needed.
Err, where would the ICE go then? Connected to the same place as on a regular Prius (ICE input of transaxle), but with the clutch across the ICE output?
 
#5 ·
Sounds interesting. I've mused over this a bit.

That would appear right to me, from the equations I've seen, except that the 3 is actually 2.6 according to a web site I checked. (That's for the Generation II prius; the Gen I may be different).

However, these things are easy to get wrong, and I'm suspicious since MG2 is supposed to be the "torque" motor and MG1 is supposed to be the "speed" motor. But maybe that's only because MG1 can add to the speed of the ICE (by spinning backwards).

With the speed reduction (and therefore torque multiplication) of 2.6, the 10,000 RPM maximum of MG1 would run out at about 3800 RPM (at MG2), which is about 64 mph (Gen II). If MG1 is limited to 6500 RPM (as it is by default when the ICE is not running), then this limit becomes 2500 RPM at MG2, or 42 mph.

Interesting. One problem is that you would not have air conditioning or other mechanical loads running during low speed operation (or if you did, you'd miss out on most (?) of MG1's additional torque).

To do this with the existing Prius inverter, you'd probably have to have a 500 VDC pack (Gen II; 273 V for Gen I) to bypass the 20 kW limit of the DC-DC boost converter.

Err, where would the ICE go then? Connected to the same place as on a regular Prius (ICE input of transaxle), but with the clutch across the ICE output?
I think 2.6 is correct. I was approximating. This thing is still a bit conceptual.

I plan on having the shaft spinning in a positive direction during low speeds and even when MG2 is fully stopped. What I picture happening is that during high command torque situations MG1 will spin negative more quickly than MG2 will spin positive due to less load. This will cause the planet carrier shaft to slow to zero speed and then go negative unless something stops it. I can apply a brake to hold it at zero speed or use some type of screw in screw out brake plate that will apply itself with a few negative rotations and then release with a few positive rotations. With the shaft being held then MG1 torque will be available at the wheel providing a boost torque.

However The screw in screw out approach will not allow the MG1 to participate in regen braking I think.

The items that may also be connected to the shaft like airconditioning, hydrolics, external ICE would be done with belts and pulleys. These could coexist with the shaft braking mechanism in theory.
 
#4 ·
Thank you for the replies.

I will plan on a higher voltage battery pack than the 200 volt pack in the prius. Could it be that the 20kw rating on the boost circuit is due to the current limit of 100amps. If this is the case then 300V gives me 30kw and so on. If I realize that I can't produce enough torque to reach higher speeds then more batteries to the rescue I would think.

I probably won't invest in batteries or a donor car until I get control of the inverter that should be here in a few days. Hopefully by then I will have learned more details about the inverter and it's control interface.
 
#6 ·
I will plan on a higher voltage battery pack than the 200 volt pack in the prius. Could it be that the 20kw rating on the boost circuit is due to the current limit of 100amps. If this is the case then 300V gives me 30kw and so on.
Well, there is a current limit certainly, but a voltage limit as well. Above a certain input voltage, the boost converter will just go phut.

I've just realised that if your inverter is for the Gen I, then it won't have a boost converter anyway; the battery and motors run at the same voltage (nominally 273 V, but it will take well over 300 V I'm sure).

If your inverter is for the Gen II but the motors are for Gen I, then the inverter may be capable of higher voltage than the motors can withstand. What might work OK is about a 312 V pack, the Gen II inverter, and Gen I motors, and you somehow disable or ignore the boost converter. With a larger pack than the stock Prius, hopefully the voltage swings will be lower, so you can get away with a higher average voltage to the inverter.
 
#7 · (Edited)
http://www.youtube.com/watch?v=2olyxIhN_HE

Based on the speed of the differential output using a 24VDC supply (see video) I calculate that my car could have a top speed of 68mph with a 240VDC battery pack and a 24inch tire.

The motors inside the prius transaxle are 3 phase brushless dc type and their back emf limits their speed. In order to go faster I would need to supply a higher voltage. This should be fine for my first grocery getter prototype.

I can't wait to start hacking the prius inverter I ordered. I will also start looking for a higher DC power source.

Cheers
 
#11 ·
Jeff, this is a very exciting project!

Are you planning to use the prius transaxle in the rear and eliminate the VW transaxle?

I also have a junkyard genI prius transaxle and inverter. I haven't had time to mess with it yet, actually wanted to use it as an ICE engine dyno as my first use of it. Might get on that project soon, and would love to have someone else to work with on it.

I have built a BLDC controller for the 16hp Mars motor, that powered my Electric Jetski (project not finished). I could pull out that controller and try to get it working with the MG, but it needs bigger power switches (inverter) to handle more than 16hp. That is what I hope the prius inverter would allow. Seems the worse case is just to use the IGBT's in it, or really my thought is even just the water-cooling technology is worth the $75 I paid for the inverter.

For an EV, I think you want the MG1 and MG2 tied together so it operates as a single electric motor. It would be very complicated to do anything. KISS. I wouldn't weld the planetary, but pin or spline the planetary gears so they don't spin.

I'm not sure what effect it has if MG1 windings are different so it spins faster at the same voltage than MG2. This might be a problem with tying them together?
 
#13 ·
Jeff, this is a very exciting project!

Are you planning to use the prius transaxle in the rear and eliminate the VW transaxle?

I also have a junkyard genI prius transaxle and inverter. I haven't had time to mess with it yet, actually wanted to use it as an ICE engine dyno as my first use of it. Might get on that project soon, and would love to have someone else to work with on it.

I have built a BLDC controller for the 16hp Mars motor, that powered my Electric Jetski (project not finished). I could pull out that controller and try to get it working with the MG, but it needs bigger power switches (inverter) to handle more than 16hp. That is what I hope the prius inverter would allow. Seems the worse case is just to use the IGBT's in it, or really my thought is even just the water-cooling technology is worth the $75 I paid for the inverter.

For an EV, I think you want the MG1 and MG2 tied together so it operates as a single electric motor. It would be very complicated to do anything. KISS. I wouldn't weld the planetary, but pin or spline the planetary gears so they don't spin.

I'm not sure what effect it has if MG1 windings are different so it spins faster at the same voltage than MG2. This might be a problem with tying them together?
Thanks for the interest. I am very excited. My plan is to not use the vw transmission. My donor car suspension needs some modification so it can accept a CV joint. It is a 66 which has a swing axle arrangement that I need to change. Then I need to make a Prius to VW axle. I am learning as I go but I think it might work.

I am not going to weld the planetary gear together yet. I want to get car rolling using MG2 first. I can keep the carrier shaft spinning using MG1 at any speed I want to keep lubrication pump going.

I then have some crazy ideas about how to use MG1. If I hold the carrier shaft stationary with a brake or gear then it will transfer 2.6X MG1 torque to the wheel through the planetary gear. I can use this for a low speed acceleration. I can then release the shaft to spin under the control of MG1 to lubricate and to run an air condition compressor or such during cruising. I could also use MG1 as a generator for my batteries when the car is parked with a small ICE and some type of pulley arrangement on the shaft if I am camping out somewhere. It would also be a cool campsite generator.
 
#12 · (Edited)
Hi guys,
Happy to see that someone is finally getting this concept to the operating stage.
I put this up over three years ago.
http://99mpg.com/Projectcars/evinsight/

I will be getting back into this very soon, as I have finally cleared the decks in my workshop.
While using the unmodified Synergy drive would allow many interesting possibilities, it seems to me that combining of the motors via the welded planetary may be the most efficient way to use the drive.
I have two second gen drives, so I will try it both ways.
The ICE shaft also runs the transmission oil pump, so from a lubrication standpoint, it is better for that shaft to always be turning to fully lube all the internal bearings.

This combined motor system also allows removing all the final drive gearing, to drop over 100 lbs of weight and the use of the ICE input shaft as an output shaft to drive any transmission, thus allowing this to power large vehicles.
The combined motors should be able to push my light weight Insight with no other transmission to well over 80 MPH.
You mention using an analog devices resolver decoder evaluation board for feedback?
What board did you use?
Mike
 
#14 ·
I used the AD2S1210 resolver to digital eval board. I plan to layout my own board with the motor control, resolver and current sensing integrated together eventually. The two eval boards I had were for me to learn how the commutation works. I still have quite a bit of work ahead of me to get a well syncronized commutation at high motor speeds.
 
#15 ·
#16 ·
thanks for the AD2S1210 info.
I was looking into the resolver interface chipset that is used in the prius, but this looks easier.
It was great to see the video of the unit actually running off the eval board.
Gets me motivated to get back on the project.

Have you tried running the motor open loop?

The dev board I purchaced for the task:
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en537020
Good luck
I got it spinning open loop first before I got the resolver board. I don't have a lot of current capacity so it was tough to get any torque during start up.

I need to build a high voltage dc supply to test out the prius inverter that I got. I want to see how fast I can get it spinning.
 
#17 · (Edited)
#18 ·
You can get a prius battery pack with BCM and contractors for $400-$600 from most junkyards as well as e-bay.
We plan on using them for another project:
http://99mpg.com/Projectcars/phevinsightiigetti/

A simple HV CC charger can be built from off the shelf switching supplies to charge it up.
http://99mpg.com/Data/resources/downloads/relateddocuments/dual_stage_grid_charger1.pdf

Of course it will not get us far in an actual car but it is a good test power source capable of > 100A.
Thanks Mike
I will seriously consider these options. I definitely want to try and capitalize on junkyard parts as much as possible. Junkyard EV is the theme of my project. I am willing to try buck and boost type of arrangements in order to make existing battery packs compatible with my system.
 
#19 ·
I got the engine out. If I am going to use the entire prius transaxle inplace of the VW transaxle then I am going to have to convert my swing axle suspension over to Indepenent Rear Suspension. I didn't know what this was until I started taking things apart. It turns out that if I bought a model later than 1973 it would already have the suspension I wanted.
 

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#20 ·
I removed the swing axle transmission and torsion spring frame. I got a later model suspension frame and trailing arms from various different make and models. I painted and assembled the new suspension.
 

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#21 ·
I installed the new suspension and fabricated some motor mounts that suspend the transaxle from the load floor of the wagon. The motor is offset because originally it would have the ICE of the prius on the other side. I will fill the empty space with batteries. My next step is fabricating drive axles that connect the prius CV joint to the VW CV joint.
 

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#22 ·
Another problem I ran into is that the direction of the transmission oil pump will be spinning in the opposite direction in the mounting configuration that I am using in the rear of the car instead of the front. I didn't have enough space to flip it around without cutting into the back seat. I am going to have to figure out an alternative way of circulating the oil. I have some ideas but nothing for sure yet.
 
#25 ·
Do you mean you rotated it upside down to place the motors to the rear,
and now the oil pump won't pick up the oil?
I haven't looked at mine recently.

Quite a bit of confidence to build this transaxle into the car before you can demonstrate it will work sufficiently. I know it is fun to do that, but I'd recommend to fully get the motor and controller working before investing the time and energy and expense to mount it in the car.
It isn't like there is a "plan b" to buy an off-the-shelf controller (AFAIK) for it.

Another problem I ran into is that the direction of the transmission oil pump will be spinning in the opposite direction in the mounting configuration that I am using in the rear of the car instead of the front. I didn't have enough space to flip it around without cutting into the back seat. I am going to have to figure out an alternative way of circulating the oil. I have some ideas but nothing for sure yet.
 
#23 ·
On this first attempt I am only going to install the larger of the two electric motors (MG2) into the transaxle. I will leave out MG1 and the Power Split planetary gears and carrier which will reduce some weight in the transaxle and simplify my control system quite a bit. After I get the car performing with MG2 only I will have a better idea of what needs to be added.
 
#24 · (Edited)
I acquired a 2001 Prius transaxle for $0 some time ago. I finally got some time to work on it. I completely took it apart and can’t find anything wrong with it. I don’t know what error code it produced to make the transmission shop swap it out.
...
My plan is to add a disc brake or clutch plate to the planet carrier output shaft where the ICE connected. By holding the shaft stationary and driving MG1 in the opposite direction of MG2 I should be able to produce a wheel torque of ( 4.1 X ( MG2 +( 3 X MG1))). I am trying to preserve the torque multiplying of MG1 through the planetary gear during low speeds. If this is correct I should be able to accelerate very quickly. At around 40mph, MG1 will be spinning at it’s max speed and I will release the brake holding the planet carrier. This should allow me to continue to accelerate using MG2 only driving the ring gear and to cruise. I will then set the MG1 speed to whatever speed is appropriate to drive the planet carrier shaft which is connected to the oil pump and to any other pump system (ie air conditioning) that I might attach to it. This configuration would also allow me the option of still using MG1 coupled with a small ICE to charge my batteries while the car is parked if needed.

My question is whether or not I am correct in my assumption about transferring MG1 torque to the wheels in this configuration and preserving the torque multiplying of MG1? Any recommendations experience on other configurations using this transaxle is welcomed?

Thank you
Jeff
Jeff, did you had a chance to check actual torque and actual power output (distribution) depending on inputs (E, mg1, mg2) - rpm, torque, power in/out?
there are numerous types of trannys - like constant torque/variable rpm and constant hp (var torque/rpm, torque for speed (rpm) trade-off: regular car gearbox tranny, cvt, etc)

on Prius site we can see rpm distribution - not torque http://eahart.com/prius/psd/
if mg1 and mg2 geared differently - what happens when load on wheels exceed max torque of weaker (low-torque) motor? high-torque motor would spin weaker motor in opposite direction... applying motor breaks would leave us with one motor not used or like tranny with overrunning clutch (one motor - high speed /low torque freewheeling over low speed/high torque input)

can we see schematically how torque distributes in this tranny? (make sense replace planetary gears with bevel gears (like in regular differential) for better visualization)
thank you
 

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#26 ·
Am I missing something? ... Don't we already know the gear ratios between the 3 points of Input1 , Input2 , and output? ... and we know the RPMs of each ... Doesn't this already tell us the power split / ratio ? ... knowing the power and RPMs of each tells us the torque of each.

Unless I am missing something??
 
#31 ·
Battery charging?

My inverter is designed to drive two motors but since I am only using it to drive one I was considering the possibility of using the empty side as part of a battery charging solution.

I am wondering if it would be possible or make sense to apply a dc power source through a series inductance to the unused MG1 motor phases and use the inverter switches as a boost circuit to charge my batteries. I would think that this is similar in function as to what is happening during regenerative braking. I will need to start learning about battery charging current and voltage profiles.

I guess I will start with acquiring a rectifier circuit that I can use to source my MG2 motor control bench testing and eventually be used as my part of my battery charging circuit if this idea works out.
 
#32 · (Edited)
I realized that I have a lot to learn about different motor control modulation schemes but last night I was able to get something working that I'm satisfied with. I attached a video.
http://www.youtube.com/watch?v=dFGa9jngbx4

I had the motor spinning before using a six-step commutation that only modulated 2 of the 3 phase at any given time and used the floating phase to sense the back emf of the motor to syncronize the magnetic field alignment. I needed to change this in order to get it to work with the high voltage prius inverter. This inverter appears to only have 3 control lines for modulating the phases which did not allow me to have one phase floating. I was directed to a Space Vector Modulation technique that seems like it will work.
I've listed the pinout on the ECU connector silk screen. Out to the side are my notes on what I think the signals are for. If anyone has experience with this inverter please let me know. I am not sure about anything until I power it up. I assume that the current sense are some sort of differential signal that will be proportional to the phase current. I am not sure what type of interface to use for these signals yet.
Thanks Jeff
 

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#33 ·
Hi Jeff,

I read your post above with interest as I am working on writing my own field orientated control for a honda brushless PM motor. I started trying to modify a microchip demo board dsp to do what I want but found it quite complex with little online support, most of the motor apps are based off a ramp up then a constant speed closed loop rather than torque control which is what you need for a vehicle.
So I switched over to using an open source microcontroller from this website:

www.leaflabs.com

Its the maple device which is an ARM cpu running at 72mhz with about 90mips of computing power. It should be plenty to run this kind of code, the compiler is free and open source and very similar to the arduino.
I am writing my motor control app from scratch and am about half way through, perhaps we should pool resources a little and it help both of us?

If you're interested drop me a PM and give me your e-mail address.

Chris
 
#35 ·
I am using the Zilog board for now only because I got it for free some years ago. I won't be surprised if I end up changing micro controller some time.

My motor has a resolver for angular position and I am using the Analog Devices resolver to digital eval board which gives me 10bits of angular position resolution. I am using this position error for phase locking my commutation steps using a PI loop. I would have to do something different if I had hall effect sensors to align my commutation switching.

I am not completely sure my modulation scheme is ideal but it is satisfactory for now. I am using a complementary switching pair scheme which should be compatible with the prius inverter. I have 6 zones that modulate the polarity of my PWM signals and another 6 zones shifted by 30degrees that will set one of the phases to half PWM duty cycle according to the zone that matches it back emf crossing. This is my attempt to better ressemble a sine wave. This seems to create the smoothest running so far.

I am sampling a pot for the PWM magnitude right now. I have example code that I will use for either closed loop speed or closed loop current once I am ready to. It is pretty straight forward and will just require a little tuning of the PI response. I first need to figure out the current sense interface on the Prius inverter before I can consider current feedback for torque control mode including reverse torque for braking.

I wanted to get the software working on my low voltage inverter first so that when I apply the same control signals to the Prius inverter I can compare the performance and better isolate any differences between inverter power stages.

Jeff
 
#38 ·
I would agree that the Zilog is underpowered for floating point math. I am only using it temporarily since it is what I had. I guess what I am doing is a modified trapezoidal since I am using 12 distinct commutation steps. The extra steps are allowing me to chop up the trapezoid a little more. I really don't know how much performance difference there will be going to a higher resolution sine wave generation. This is my first real exposure to motor control. I was impressed with how some of the Zilog example code is structured to compensate for its computation limitations. Everything is done using lots of "if" statements since it is all unsigned arithmetic.

I think I figured I had around 4000 clock cycles (20MHz clock) between my 12 commutation events if my 8 pole motor is spinning at 6000 rpm. I don't think that this is going to be enough to do all the control I will want to do so I will be interested in upgrading to more processing power.
 
#43 ·
Great project!

Have you considered a Parallax Propeller microcontroller? It has 8 parallel, concurrent processors to which you can assign different tasks.

I built a 3 phase vector controller using one using one processor per phase to produce the PWM in the background with other processors managing other parts of the problem. Because they all work concurrently it lessens the timing problems a great deal.

As the RPM increases, the resolution of the sine wave generation is reduced. At low rpm, the sine wave is split into 255 time slices, each with a different PWM value. At maximum speed, there are only 8 slices. Again, this reduces the processing overhead.

The important parts - the PWM mainly - were written in Assembler and the rest in it's native high level language - 'SPIN'.

For traction use, I found the most effective control, most similar to an ICE gas pedal, was to control only the slip angle between the generated field and the resolver output which is equivalent to controlling the torque.

Keep up the good work!

Si
 
#44 ·
Great project!

Have you considered a Parallax Propeller microcontroller? It has 8 parallel, concurrent processors to which you can assign different tasks.

I built a 3 phase vector controller using one using one processor per phase to produce the PWM in the background with other processors managing other parts of the problem. Because they all work concurrently it lessens the timing problems a great deal.

As the RPM increases, the resolution of the sine wave generation is reduced. At low rpm, the sine wave is split into 255 time slices, each with a different PWM value. At maximum speed, there are only 8 slices. Again, this reduces the processing overhead.

The important parts - the PWM mainly - were written in Assembler and the rest in it's native high level language - 'SPIN'.

For traction use, I found the most effective control, most similar to an ICE gas pedal, was to control only the slip angle between the generated field and the resolver output which is equivalent to controlling the torque.

Keep up the good work!

Si
Hi Simon,

I didn't know you could get away with such low resolution of the change in PWM? I am aiming my firmware to have be able to set each PWM duty cycle on every duty cycle period. I did consider doing half instead, so the PWM frequency would still be 10khz but the update rate would be 5khz, this would give me 200 microseconds time in between rather than 100 microseconds.
 
#48 · (Edited)
My inverter does not look like nimblemotors.

I think mine is from a 2002 prius. I doesn't look to me like I have a DC boost circuit. I think it is considered a gen 1.

I think nimblemotors's inverter does have the DC boost circuit if that is the little black box that the battery mains are going to before the phase switches. So it would be a gen 2 not a gen 1. Just a guess.
 

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#49 ·
yes you are right, it was supposed to be out of a 2001 prius when I bought it, but having looked at the pictures from hobbits teardown,
http://techno-fandom.org/~hobbit/cars/ginv/
it is the same and has the DC-DC of the genII. Not sure if this is good or bad! So the DC-DC also have some controls?
At least now I can try to find the right pinouts. I don't work for ALLDATA any longer, so don't have access to the online manuals anymore.
Maybe zaxxon can show the pinouts for the genII ?

In Hobbits analysis,
"When GUU is low,
the lower transistor of the pair is turned on; when GUU goes high, it turns
off and the upper transistor turns on. There is NO both-off state, except
for when the overall "gate" lead goes low and then all the transistors turn
off [i.e. the definition of "neutral" in the car].

This switching works down to DC and has a little hysteresis, changing state
as the input rises above 8 volts and again as it falls below 6.8 or so. No
IGBT gate output appears until "xSDN" is brought high, and then the next
rising or falling edge at the "xyU" lead starts producing output.
"


My inverter does not look like nimblemotors.

I think mine is from a 2002 prius. I doesn't look to me like I have a DC boost circuit. I think it is considered a gen 1.

I think nimblemotors's inverter does have the DC boost circuit if that is the little black box that the battery mains are going to before the phase switches. So it would be a gen 2 not a gen 1. Just a guess.
 
#51 ·
After I get reasonable performance out of this gen1 setup, I plan to do the same with the gen 2 transaxle with the higher wattage MG2. I was reading about the different magnet configurations that produce more torque at lower currents. The trade off is that it takes higher voltage to spin it up to the same speed as the gen 1. I plan to remove the DC boost circuit altogether and go with a 500 battery pack and approach the 50kW rating. We will see how this works out.

Jeff
 
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