Driving a PMSM with space vector modulation

Question

I want to drive a PMSM in open-loop with 3 phase shifted sinewaves.

I convert the sine output to alpha-beta frame and give it to the space vector modulation block. However i am doing smething wrong as the outputs of the SVM don't seem alright and the motor doesn't turn.

I believe it's a simple error on my part but it would help if someone takes a look.

Regards
Srinath

Answer 1

Your model has the following issues:

1. You are using the Space Vector PWM (3-Level) block instead of the regular

   Space Vector PWM appropriate for a 2-Level converter

2. The units on the SVPWM input block are misaligned.  The Vdc input is 200V but the Vab input is only +/-1 leading to very low duty ratios.

3. The sinewave frequency is somewhat high at 600 Hz so you will see oscillations in speed once you resolve the above two issues.

    

Comments

Thank you, i made the corrections you suggested.

But the output speed oscillates (both positive and negative). I suspect this is because the inverter is not being used correctly.

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The oscillations are due to point #3 above.  The motor is not synchronous with the PWM signals you are generating.  Try a lower frequency like 100 Hz for your Sine Wave Generators.

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Thanks, that fixed it