Driving MPSM motor

[MPP2007]

Hi

Checking aplication notes from Atmel/Microchip or NXP, I found some ways to control PMSM motors, by PMSM I mean DC motor with sinosuidal back EMF.

1. way is to use SVM, with 3 Hall sensors and sine table - AVR447: Sinusoidal driving of three-phase permanent magnet motor using ATmega48/88/168

2. way is to use SVM but with Clark/Park transforms

Which way to go to run my Lexus 50kW MGR ?

[samwichse]

Well that's a hell of a first post.

I looked it up, and
https://www.microchip.com/design-cen...chronous-motor

The Permanent Magnet Synchronous Motor (PMSM) is an AC synchronous motor whose field excitation is provided by permanent magnets, and has a sinusoidal Back EMF waveform.

SVM is Space Vector Modulation

https://www.mathworks.com/solutions/...ransforms.html

The Clarke transform converts the time domain components of a three-phase system (in abc frame) to two components in an orthogonal stationary frame (αβ). The Park transform converts the two components in the αβ frame to an orthogonal rotating reference frame (dq). Implementing these two transforms in a consecutive manner simplifies computations by converting AC current and voltage waveform into DC signals.

None of this is helpful to you, but yay! I'm learning. Hopefully someone more knowledgeable then me will be along shortly.

[MPP2007]

I did some tests on this motor connected to simple V/Hz inverter. (Dinverter 0,25 kW). It starts at 4Hz with very slow motion. Due lack of power and internal current limits of inverter, I can’t spin it to higher rpm.

[thingstodo]

Originally Posted by MPP2007

Hi

Checking aplication notes from Atmel/Microchip or NXP, I found some ways to control PMSM motors, by PMSM I mean DC motor with sinosuidal back EMF.

1. way is to use SVM, with 3 Hall sensors and sine table - AVR447: Sinusoidal driving of three-phase permanent magnet motor using ATmega48/88/168

2. way is to use SVM but with Clark/Park transforms

Which way to go to run my Lexus 50kW MGR ?

Hi

I don't have access to the source code from work (where I'm reading this) ... so this is all from memory (which is not that great, and I didn't understand all of what Paul was doing when he did explain it)

With that disclaimer ... here is what I remember

Paul Holmes uses an encoder for rotor position. It is closer to your option 2. The encoder position is used to figure out where the rotor is with relation to the position of the stator flux. Getting them to the same units so that they can be compared requires 2 sets of calculations. The Park transform is one of them. Another ... 2 equations? .. to take the error in rotor position and reflect that back to a torque current setpoint, and from there combined with the magnetizing current to get a voltage setpoint and the PWM timing.

The hall sensors are likely more accurate than a separate external encoder. But I don't have information on which of your 2 options would be easier, or which would give you better control

[thingstodo]

Originally Posted by MPP2007

I did some tests on this motor connected to simple V/Hz inverter. (Dinverter 0,25 kW). It starts at 4Hz with very slow motion. Due lack of power and internal current limits of inverter, I can’t spin it to higher rpm.

There are a couple of guys on this forum

http://openinverter.org/forum

that will understand what you are talking about .. and will likely have opinions for you. Johannes Hübner particularly ... he's the guy that works with Damien on his add-on /replacement boards for the Teslas, Leafs, etc

[MPaulHolmes]

For a 50kw motor I would definitely go with the space vector modulation and the field oriented control (clarke and park like thingstodo was saying). Then you can control the torque of the motor rather than the speed, which I think is better for driving around. The toyota mgr is also a highly "salient" motor, which means you need negative Id in order to get the maximum torque per amp, and the amount of Id varies as a function of the torque command.

[freebeard]

Which way to go to run my Lexus 50kW MGR ?

Is this by chance the rear axle from the LX400h? Because if it is, I'm very interested in your results. There is a thread from 2014 here: https://ecomodder.com/forum/showthre...mgr-29878.html

I tried to talk to Michael Bream at EVWest about using this or similar units (RAV4), but he was dismissive — saying they're designed to work as a hybrid and don't have enough torque. His customers 'want Tesla installs'.

Is the 4,000 rpm at no load?

[Piotrsko]

EV WEST tends to NIH. However, here they are kinda correct since hybrids have tended to use the motor as an asist, and their reputation is hipower $$$$ conversions

[freebeard]

...here they are kinda correct since hybrids have tended to use the motor as an asist...

To be fair, he did say he'd want to see dynamometer results. I suspect he was thinking of the MGR1 and MGR2 integrated with the ICE. The MGR3 is a stand-alone unit with 68hp compared to the Zelectric (typical?) 102hp at at least double the weight.

Due to his lack of interest, we never discussed the external oil cooler option.