TMS320F28027F: InstaSPIN: Configure PWM Frequency in Runtime

Prakash Krishnaswamy61

Part Number: TMS320F28027F

Hi All,

We're developing VFD using InstaSPIN. We need to make PWM frequency configurable during run-time. This is controlled by #define USER_PWM_FREQ_kHz in user.h. It is being used in 72 places as compile time constant. Is InstaSPIN designed for a fixed PWM frequency? Any ideas for changing it in runtime? It's even used in ctrl.h.

Thanks,
Prakash

over 7 years ago

0 Yanming Luo over 7 years ago

TI__Guru** 115480 points

The instaSPIN-FOC can't support changing the PWM frequency online during the motor is running. You may only change the PWM frequency when the motor stops.

You may change all variables that are related to USER_PWM_FREQ_kHz in the gUserParams object, and then call CTRL_setParams().

0 Prakash Krishnaswamy61 over 7 years ago in reply to Yanming Luo

Prodigy 20 points

Thanks for your response! We wanted to change PWM frequency only when motor is stopped. As I already mentioned USER_PWM_FREQ_kHz is also used in ctrl.h at CTRL_angleDelayComp. I may need to change that also rt? I think it will be better if constants from user.h is not directly used in the library and all the one time calculations done in an init function. It will be easier to make them configurable.

0 Yanming Luo over 7 years ago in reply to Prakash Krishnaswamy61

TI__Guru** 115480 points

Good suggestion. Yes, you have to change this accordingly. We would like to modify this in the next generation motor control SDK. Thanks.

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TMS320F28027F: InstaSPIN: Configure PWM Frequency in Runtime