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Discussion Starter #1
In a quest for more power from the IMA system I've started investigating the Motor Drive Module (MDM). As expected it's a beautifully designed and massively conservative in it's specs with lots of headroom for increased power flow.

I'm working with Jeremy a very clever chap in UK with a few ideas about how we can boost assist level. This is mainly again for the Insight UK Rally car, but anything we find out of course could be very useful for us all. The lifebatt batteries I've just ordeded can do 200A discharge so that looks a very appealing possibility!! I'm setting my sights initially on a 50% increase in assist if the motor will stand it.

Anyway here are some photos of the MDM in pieces.

It has three 350V 1750uf power filter capacitor in parallel fed from the main power input. This then feeds a fairly standard looking Mitshuishi IGBT power module. Now I can't find the exact data sheet for it yet but extrapolating from others in the range it appears to be rated at 250A at 600V. Plenty of overhead there IMO.

The output from the power igbt module goes through three current sensors (One per phase) and straight to the motor.

www.solarvan.co.uk/mdm/IgbtModule.pdf

www.solarvan.co.uk/mdm/MDM001.jpg
www.solarvan.co.uk/mdm/MDM002.jpg
www.solarvan.co.uk/mdm/MDM003.jpg
www.solarvan.co.uk/mdm/MDM004.jpg
www.solarvan.co.uk/mdm/MDM005.jpg
www.solarvan.co.uk/mdm/MDM006.jpg
www.solarvan.co.uk/mdm/MDM007.jpg
www.solarvan.co.uk/mdm/MDM008.jpg
www.solarvan.co.uk/mdm/MDM009.jpg
www.solarvan.co.uk/mdm/MDM010.jpg

For some light bed time reading here is a pdf about BLDC motor control

www.solarvan.co.uk/mdm/MotorControl.pdf

Peter
 

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Interesting.

How much torque do you think the system will handle?

I suspect they gave themselves a safety margin ... but they also were trying to keep everything as light as possible ... so it might not be a very large safety margin.

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If it pans out I wonder about a single MDM then powering two IMA motors.
 

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That is interesting. I'm surprised about the trapezoidal vs. sine discussion in the motor control PDF. Apparently the BLDC vs permanent magnet synchronous motor is way more standardized than I thought... just trapezoid and sine windings, and the hall effect sensors imply it's trapezoid/BLDC.

Anyway, you could try scaling the current sensor outputs. I think if you scale the phase sensors, the DC sensor, and the battery sensor by the same percentage you'd max out the motor before the MCM knew anything was wrong. It could possibly tell that the rise time is too slow, but I'm guessing there's a lot of latitude on that. There's a current fault output on the power module, but it's digital.
 

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200 amps at whatever voltage those cells are at with that much load on them should produce enough power for a moderate pace of acceleration, at least when ignoring the gas engines compression load. Just remember that once breakdown torque has been reached any additional power could cause demagnitization, unfortunetly I don't think that this would be easy to test for, although I suppose a dynamometer could get pretty close as long as the engine doesn't interfere too much.

Now you've got me daydreaming of three IMA motors stacked in the engine bay with 600 amp total peak with an appropriately sized(200Ah or so)pack, instead of the HPEVS AC50 that I was dreaming about earlier, that could be about 78 horsepower and with more torque available throughout would make the Insight into a bit of a speedster.
 

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Discussion Starter #5
How much torque do you think the system will handle?
No idea, but It seems they allowed themselves 100% headroom on the electronic specs for every component which seems to be borne out looking at the MDM internals. Hopefully motor is the same. But if we can get 50% than that would be good!

If you mean how much torque will the drivetrain stand, gearbox, driveshafts etc then again no idea.

If I can get +50% then I might keep going until something breaks or I reach 200A which will be the limit for my cells.

Anyway, you could try scaling the current sensor outputs. I think if you scale the phase sensors, the DC sensor, and the battery sensor by the same percentage you'd max out the motor before the MCM knew anything was wrong.
Well spotted that's the initial plan!! I haven't look at the sensor in details yet though so don't know what the output is. They are three wire types through.
 

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any additional power could cause demagnitization, unfortunetly I don't think that this would be easy to test for
You know... it occurred to me that instead of going up and up until something random breaks.

Another method would be to test the magnets without risking breaking other things... after all the demagnetization issue is just about how our particular magnets react to the temperature and magnetic field strength on the magnets themselves.

If we send in a small sample of the IMA motor magnets to get properly tested somewhere ... we could find out exactly what they are made of ... and exactly what kind of specifics we need to keep in mind for Magnetic field strength , temperature , etc...

Once we know that... then we know that at least the IMA motor itself should be kept __% bellow that maximum to avoid progressive damage.

Than we should know what our peak upper limit is for the IMA motor itself.
 

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Discussion Starter #7 (Edited)
Another method would be to test the magnets without risking breaking other things... after all the demagnetization issue is just about how our particular magnets react to the temperature and magnetic field strength on the magnets themselves.

If we send in a small sample of the IMA motor magnets to get properly tested somewhere ... we could find out exactly what they are made of ... and exactly what kind of specifics we need to keep in mind for Magnetic field strength , temperature , etc...
Be my guest it's a good idea. I've only got one spare IMA motor so can't afford to sacrifce that by removing magnets etc.

I quite like the dynamometer idea.

If we slowly increase power we should see a fairly linear upwards power/torque slope until we get to the magnet saturation/overload point. When further current fails to produce more power we could back off 25% pronto and set that as our upper current limit.

Of course the motor might be very overated and we blow up the igbt driver before we reach max power!! Now that would be impressive!! :)
 

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Be my guest it's a good idea. I've only got one spare IMA motor so can't afford to sacrifce that by removing magnets etc.
I don't want to sacrifice the IMA motor from my car... so I will have to keep an eye out for a junked one... it doesn't even have to work... I would just need pieces of the magnet.

I quite like the dynamometer idea.

If we slowly increase power we should see a fairly linear upwards power/torque slope until we get to the magnet saturation/overload point. When further current fails to produce more power we could back off 25% pronto and set that as our upper current limit.

Of course the motor might be very overated and we blow up the igbt driver before we reach max power!! Now that would be impressive!! :)
That would be another fine option ... I guess even if it doesn't tell us what the IMA motor's limits are ... it would still show us what is the weakest link in the chain... or what goes first as power increases ... and about where that point is reached.
 

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Discussion Starter #9
I'm struggling to get the data sheet for the Honda IGBT Module, Mitusbishi won't send me one as it is a discontinued Honda special part. However they have confirmed it is a 250A 600V IPM IGBT module, so seems to have reasonable overhead for some tweaking. I would hope 150A current should be possible without blowing it up. Possibly 200A for short periods if we are very lucky and something else doesn't melt first!

I've taken one of the phase current sensors out for some testing to see if it a voltage/current output. It comes apart very easily and the pcb is marked with power and signal etc but all the components are covered by a very substantial looking EMI shield so no clues from looking at it. Need to power it up and put some current through the sense coil.

I'll also need to upgrade the IMA 100A main fuse. Anyone know the spec and part number so I can see if they do a 150A or 200A version.

What about the MCM & BCM current sensors, Mike didn't you do some work on them, where is that data please?
 

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I'll also need to upgrade the IMA 100A main fuse. Anyone know the spec and part number so I can see if they do a 150A or 200A version.
IMA fuse:

Littelfuse
EV45100H
L4G09F
Assembled in Mexico

Is that enough?
 

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Discussion Starter #11
IMA fuse:

Littelfuse
EV45100H
L4G09F
Assembled in Mexico

Is that enough?
Ian Thanks but I could not find that listed. I checked my fuse which is a Littelfuse L50S 100A which is a standard part and available upto about a 1000+ amps!!!

They do a 150, 175 and 200A version. I think I'll order a 150 and 200A version so I can move up if it all holds together at 150A.

Hmm they look difficult to get hold of over here :(
 

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Ian Thanks but I could not find that listed. I checked my fuse which is a Littelfuse L50S 100A which is a standard part and available upto about a 1000+ amps!!!

They do a 150, 175 and 200A version. I think I'll order a 150 and 200A version so I can move up if it all holds together at 150A.

Hmm they look difficult to get hold of over here :(
Sorry it didn't pan out... Makes me wonder now if the new battery pack I now have uses the L50S , or the other one my old pack had?

At least you've found suitable options ... which was the goal.
 

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Discussion Starter #13
I've sent a sample order to Littlefuse for a 150 and 200A variant of the L50S 100A OEM fuse. Hopefully they will send me a couple, if not may have to get someone in US to buy them as they are not stocked over here in UK.

I'm looking at the phase current sensors next to see how we can fake/adjust the output to get the power increase we are after. I note these are 5v devices with a resting output voltage of 2.5v and feed directly to the MDM module along with the total current MDM sensor, probably have to fake that as well, and possibly the battery current sensor (But might be able to fake that with BCM Interceptor). Hmm?

Don't know if they (Phase sensors) have a voltage ouptut or current output yet.

Mike where is that data/work you did on the other current sensors?
 

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if not may have to get someone in US to buy them as they are not stocked over here in UK.
Let me know.
As long as it is in my budget for time and $ , I'm happy to help.
 

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Peter,
Do you mean this:
Battery packs exposed - MIMA Honda Insight Modified Integrated Motor Assist

I bought one of my IMA motors from a guy that was building an electric trike, and he thought that he was going to use the IMA system for the power plant. He acquired a better BLDC motor but used the Insight 3 phase drive to power it. For the control signals he used one of the Microchip development boards, which was able to drive the Insight power electronics and eliminate the MCM.
Development Tools
Not sure which board he used.
I suspect that the MCM is the final word on what the max current will be, and if you drove the inverter with 3 phase signals generated with another source other than the MDM, you should be able to crank out as much power as you dare.

Mounting an IMA motor on bearings so I can try running it without the rest of the car, is near the top of my project list.
I have the bearings, and have fabricated a drive shaft which mounts to the rotor, but have not decided if I want to build a complete new housing for the thing, or use the existing frame. If I make a complete new housing, I can seal and weather proof the thing, as well as make the thing as compact as possible.
 

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Discussion Starter #16
That's very interesting Mike thanks.

Do we have any idea who that guy was or his contact details. He may have discovered some useful info we could use. Can you pass them to me please.

I see the battery sensor was a current loop type, was the MCM sensor the same?

Thanks
 

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Here is the guys website where he shows some of the construction photos:
http://www.craigshaffer.com/dart.shtml

He was a battery engineer at A123, and the last I heard, he had moved and was working at Segway.
He was into a lot of projects, and by looking at the website, he may not have finished the thing?

I did not open one of the other current sensors, so I can't say if it works the same way, but that is one of the more common hall effect current sensor circuits.
Power up one of the sensors on the bench, and put a test current through it, and a potentiometer on the output.
A voltage output sensor will give a constant voltage with a variable load resistance, the current loop type will have a CC at a set current, so the voltage will change as the load resistance changes.
You can also test the circuit that the current sensor feeds into, and see if it is high impedance or is a lower value resistor to ground to get more information.
 

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Discussion Starter #18 (Edited)
Mounting an IMA motor on bearings so I can try running it without the rest of the car, is near the top of my project list.
I have the bearings, and have fabricated a drive shaft which mounts to the rotor, but have not decided if I want to build a complete new housing for the thing, or use the existing frame. If I make a complete new housing, I can seal and weather proof the thing, as well as make the thing as compact as possible.
Missed the fact you have started on this. Very interesting! If the motors will stand more power say 15kw then two together would provide a reasonable motor for an EV Insight.

Three would be quite impressive!

I worry a bit about two or more sandwiched together and how the magnetic fields of the adjacent motors would interact. But you could probably drive them in parallel with one upgraded MDM if they are in exact allingment with regard stator/rotor etc. Only one set of commutation sensors reqd as well.

It might be possible to machine a nylon or alloy spacer the same shape/size as a motor housing to go in between motors if reqd.

Def like to see pics of it up and running with your bearing setup. :)
 

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I have three of the motors, one attached to the engine and tranny in the green,future EV insight.
I think that for the EV insight, I will be going with my modified Prius synergy drive. The Prius drive has built in liquid cooling system, forced oil bearing lube, differential, parking pawl, final drive reduction, sealed housing, and the two motors driven together should get me up to over 90MPH, and burn the tires if cranked up to full power. The whole drive weighs 220 lbs.
EV Insight with a Prius heart - MIMA Honda Insight Modified Integrated Motor Assist

I will be doing some magnetic circuit analysis, once I get it running. There are two versions of the commutation ring,the 2000 has a ring that is one piece and looks like the it was welded in a fixture.
The later motors have a lighter stamped ring that attaches to the flywheel.
I suspect that the hall sensors have a built in magnet/coil that simply senses the presence of the tab on the commutation ring by the effect it has on the sensor generated magnetic field. This is a common design for magnetic proximity sensors.
 

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Discussion Starter #20
I've managed to track down a 150A & 200A fuses same type as the 100A one used in Insights so I'll be upgrading that in next couple of weeks. I've also upgraded my BMS current sensor to 200A to cope with any increased currents. The cells are rated for 200A discharge. I'm still tinkering with the phase current sensors so will keep you updated. Once I have the recently finished Lifebatt upgrade working fully and some basic data then I'll start looking at tweaking the power via the phase sensors.
 
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