TMS320F2800156-Q1: Motor start sensorless with instaspin in EV compressor application

A.W

Intellectual 510 points

Part Number: TMS320F2800156-Q1

I find one issue with motor start under full load with instaspin fast enabled.

The motor stalls at 2Hz, which equals to the force angle, is it stuck in open loop?

What will cause this issue?

The phase current is as below showing.

For 1st start, motor seems not go to the close loop ,and stuck at open loop with 2Hz, and the phase current is only 20A, not reach the max start current 50A.

For 2nd start, it will go to 600rpm and than drop to 2Hz and wait for 1s , than go to the target speed.

Application is 800V EV compressor with a 8P12S IPMSM, and test with liquid refrigerant in the compressor.

Regards

2 months ago

0 Yanming Luo 2 months ago

TI__Guru** 116930 points

It's normal for the motor to start with a very heavy load, even above full load. You might refer to chapter 14 "Managing Full Load at Startup, Low-Speed and Speed Reversal" in InstaSPIN-FOC and InstaSPIN-MOTION User's Guide

https://www.ti.com/lit/spruhj1

Enable stator Rs recalibration before startup
Enable forced angle
Make sure that the current ADC offsets are calibrated.

0 A.W 2 months ago in reply to Yanming Luo

Intellectual 510 points

Is the fast estimator in open loop or close loop state when the speed staying about 2Hz，and not ramping up to the target speed?

Just like the first current scope shows, because the phase current is not the max start current, and it seems at this moment, the speed loop should be in saturation state, the q aixs current should be the max current limit.

Regards

0 Yanming Luo 2 months ago in reply to A.W

TI__Guru** 116930 points

The rotor angle and speed can't be estimated correctly at full load at very low speeds near zero. So the speed loop will not work correctly. It is a challenge for any sensorless-FOC to start and run the motor over full load. You can follow the guide to try the suggested steps.

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TMS320F2800156-Q1: Motor start sensorless with instaspin in EV compressor application