Prius synergy drive as EV drive

5560 Views 18 Replies 7 Participants Last post by Mike D EV, Apr 19, 2010

Mike D EV

Discussion Starter · Sep 11, 2007

I have added an EV mode to my Honda Insight.
http://www.99mpg.com/projectcars/mikesinsight/
But want to take it to the next level and make a full electric Insight, I have been playing with the electric drive part of a Toyota Prius as the motor.
The synergy drive minus the gas engine weighs ~220 lbs.
This assembly has the 40HP MG2 that drives the prius in electric mode, and the 15HP MG1 which normally runs as a generator. Lots of torque is available.
A simple hack of the planetary assembly will allow the two motor/generators to run in parallel. I am presently working on a hack to the cars stock inverter that would allow full control of both motors. The cool part of the system is that the 4:11 drive reduction and differential are included. This means that with some CV axle modifications/ adaption, the system could drop into most front wheel drive cars in place of their motor/transmission.
A description of the synergy drive hack is at:
http://www.99mpg.com/Projectcars/evinsight/
Mike

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OHM

· #2 · Aug 13, 2008

bump
Just wondering to what point you got up to with the Synergy drive?
Im thinking of buying one from an 06 model which is more powerful?

Mike D EV

Discussion Starter · #3 · Aug 13, 2008

That project is on hold until I build the next batch of the MIMA modifications for the Honda Insight.
I have the Inverter, and two of the synergy drive trannys, one has been modified with the welding of the planetary gear so the two motors work together.
The actual Hp of MG2 is closer to 67 than the 40 I originally posted.

xrotaryguy

· #4 · Aug 14, 2008

Nice. I am rather interested in seeing how this turns out too. Those hp numbers are peak ratings right?

Technologic

· #5 · Aug 14, 2008

xrotaryguy said:
Those hp numbers are peak ratings right?

almost all generators HP is based in peak ratings... so I'd say yes.

OHM

· #6 · Aug 14, 2008

Mike D EV said:
That project is on hold until I build the next batch of the MIMA modifications for the Honda Insight.
I have the Inverter, and two of the synergy drive trannys, one has been modified with the welding of the planetary gear so the two motors work together.
The actual Hp of MG2 is closer to 67 than the 40 I originally posted.

Mike I had a read of your Blog and some nifty hacking with Cajones.
Good to hear its more like 67 as I thought perhaps the early ones had 40.
I can also get the rest of the inverter and harness.

The donor had a Nimh battery thermal runaway issue and took the whole cabin with it. Go Nimh make more of these parts available to EVers!

Mike D EV

Discussion Starter · #7 · Aug 14, 2008

The drives I have are the second generation system,This page compares the two versions.
http://www.electrifyingtimes.com/prius2004.html
The 10KW MG1 is usually not considered in the HP ratings but in my welded planetary configuration the two together with the second gen HV inverter, we should see more like 60KW.
The interesting number is the torque, which combined should be in the 350 FT lb range. On a light weight Insight, that should burn tires.

OHM

· #8 · Aug 15, 2008

80hp and 350lbs torque is ridiculous!!
I was reading some information on the inverter that someone was hacking and analyzed to find that its actually a slave to the ecu.
This should create some difficulties in the conversion no?

Mike D EV said:
The drives I have are the second generation system,This page compares the two versions.
http://www.electrifyingtimes.com/prius2004.html
The 10KW MG1 is usually not considered in the HP ratings but in my welded planetary configuration the two together with the second gen HV inverter, we should see more like 60KW.
The interesting number is the torque, which combined should be in the 350 FT lb range. On a light weight Insight, that should burn tires.

aeroscott

· #9 · Aug 15, 2008

OHM said:
80hp and 350lbs torque is ridiculous!!
I was reading some information on the inverter that someone was hacking and analyzed to find that its actually a slave to the ecu.
This should create some difficulties in the conversion no?

it will be a goer . the inverter could be hacked by replacing the control side , cheap in parts expensive in programing . as time goes buy we will be sharing / learning how to tune and write the software . I for instance am almost completely lost on programing , but it will come.

Mike D EV

Discussion Starter · #10 · Aug 15, 2008

I don't have a running prius to play with, but from some test that a friend has done with a scope, it looks like the rotational position encoder information is sent to the engine controller, which generates the three phase drive signals that are fed to the power electronics.
Once the relationship of the encoder to the drive signals are determined, programming a microcontroller to generate equivlant signals under external control should be quite easy. Just need to tell the inverter what you want it to do.
Once I get the next batch of MIMA systems built and out the door, I hope to tackle the job, but I put the ideas out there so any other like minded people could contribute. Any Prius owners with a service manual and some test equipment that would take the time to work out the signals required, could help get this started.

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OHM

· #11 · Aug 15, 2008

Yes please there must be more Prius wrecks out there ready to tamper with.

On another note does anybody know if thermal runaway is common on the battery packs? The one I can buy suffered this with the original Nimh.

tomfwtexas

· #12 · Jan 20, 2009

Great project. I've been working on the same design for some time when I ran across your post. I'm picking up an Insight this week for the conversion ('01). I have the prius trans and inverter and will be starting the design for the controller to drive the inverter in the next few weeks. The prius dose use a reluctance position encoder for phase timing unlike the honda which uses hall sensors. I like your idea of synchronizing the motors to use one input control signal. It greatly simplifies the controller design. I'd like to use the prius ECU but with no information on it I think that a custom design might be easier. One possibility for an off the shelf solution is the Galil (www.galilmc.com) controller. I've used several in CNC projects and they work very well. A three axis version is available and would also provide all the commutation as well as the PID functions for tuning. (you can combine axis to provide three phase drive for ac motors). Just need to work out the interface to the prius inverter. If their is any thing I can help with on your project count me in.

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Technologic

· #13 · Jan 20, 2009 (Edited)

OHM said:
Yes please there must be more Prius wrecks out there ready to tamper with.

On another note does anybody know if thermal runaway is common on the battery packs? The one I can buy suffered this with the original Nimh.

any Ni-MH vented or not can have thermal runaway from poor battery cooling, quick charging, or quick discharging.

To hedge this you can either install a temp sensor, or simply cool the battery cases.

Mesuge

· #14 · Apr 19, 2010 (Edited)

aeroscott said:
it will be a goer . the inverter could be hacked by replacing the control side , cheap in parts expensive in programing . as time goes buy we will be sharing / learning how to tune and write the software . I for instance am almost completely lost on programing , but it will come.

Blast from the past, well the Toyota HSD drivetrain to e-converison seems never happened. After all those years and millions of these hybrids sold (and god knows how much crashed/written off), strange and shall we say humbling..

You are right that one, probably the most straightforward approach is just to use the stock inverter as any other IGBT power stage/module on the market and replace/hook it up with own driving pcb (DSP) based on ARM cortex, which are pretty advanced these days and available ready-made in many flavors, under $500, some even with motor self-learning software routines etc. The other approach, leaving the inverter box intact and just hacking it layer above in the hybrid system ECU was a dead end, since you depend on the other stuff/systems in the car, which must be either left in state of confusion (error codes) - dangerous, or software replicated (faked) and/or physically transplanted from the hybrid donor, which is a bit pointless.

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Mike D EV

Discussion Starter · #15 · Apr 19, 2010

The EV insight project is not dead, just waiting to come to the top of the project list which seems to constantly get longer,
The project will move up a notch this friday when we pull the insight motor/transmission out of the green Insight and get the synergy drive and inverter on a test stand.
The hot project right now is to build a data acquisition interface to an Insight from CA. that will be going for the automotive X-Prize.
I am also developing a complete battery test and rebuilding system for Honda HV battery packs.
http://99mpg.com/blog/whatactuallygoeswr/
http://99mpg.com/Projectcars/mimapackwhack/
http://99mpg.com/blog/batterypacksexpose/

I was thinking recently that at least for initial testing, the inverter may be able to be driven open loop, which could be as easy as using a small 3 phase motor controller from the radio control world to drive the Prius inverter.
Too many projects,not enough time or money.

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Mesuge

· #16 · Apr 19, 2010 (Edited)

Great to hear, that the transplant project is still alive, as you know, the inverter is heavily tweaked for their perm motors and hybrid pack (the inverter box includes VDC booster unit), so the closed loop might eventually be necessary, these hybrid motors have their own encoders/sensors build it, correct? In terms of output, are you going to be interested in exploring both options, since this is dual capable controller:

1/ running MG2 and MG1 at the same time (welded?)
2/ or just MG2 solo

The #2 could be used in RWD direct drive or tranny setups, picture MG2 shaft connected face-2-face with such tranny ala BMW/Miata etc., the rest of it like MG1 gutted out, (I noticed you are primarily exploring the "welded option" though)?

Mike D EV

Discussion Starter · #17 · Apr 19, 2010

The encoder is actually a resolver that generates a 10khz phase shifted sine wave, which is digitized into a rotation angle in the ECM.
Not as simple or standard as the hall sensors that are normally found on BLDC motors.It may be easer to just add some hall position sensors?

Once we get into it, we will explore all options.

The welded planetary is the only way to use both motors,without an input on the ICE shaft, and to spin the internal oil pump.

Cannot see any advantages in leaving the planetary stock, as there is no mechanical advantage gained and the second motor which splits power between the ICE and MG2 in the stock system would not be able to contribute any torque.

Mesuge

· #18 · Apr 19, 2010 (Edited)

On the encoder/resolver question - it might be worth exploring hookup with some pre-made box, which will digitize the analog input from resolver sensor into desired digi output feeding the inverter/dsp, resolver-2-digital pcb or such, someone-somewhere must have it, 12bit resolution should be enough..

Let me explain the #2, what it means is just powering the MG2, the planetary, MG1 and diff. are discarded. Yes you loose some "theoretical" torque and kW output gain from the #1 (welded scenario), but it will be much easier to get to work (and less weight), ~50kW not bad for donor-econoboxes, I know not that many in RWD around anymore. As I tend to think with the #1 option it won't be that trivial to set it up and run properly from the DSP point of view.

Mike D EV

Discussion Starter · #19 · Apr 19, 2010

If you split the synergy drive you loose the tranny,the differential, final drive reduction, parking pawl, environmental seals, and forced oil lubrication.

Synergy EV drive conversion:
Remove old engine and tranny
Mount synergy drive in the car
Make adapter drive axles to go from the Prius to whatever was in the car
plug in the drive axles
Connect inverter
Install inverter controller
Install 208V battery pack
you are good to go.
Of course the devils in the details.

With only MG2, you will have to put weight back in with a transmission/differential, adapter plate and custom splined shaft with no side load capabilities.

I have the MG2 half of the synergy drive we used for our synergy drive demo.
http://99mpg.com/workshops/understandingdiagn/
I was thinking of using it for a Big e-wheel for my Van
http://99mpg.com/Projectcars/ewheelforanyvehicl/

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