TMS320F28027: overmodulation

zhou qicheng

Part Number: TMS320F28027
Other Parts Discussed in Thread: MOTORWARE

Hello,

I use D:\ti\motorware\motorware_1_01_00_18\sw\solutions\instaspin_foc\boards\boostxldrv8305_revA\f28x\f2802xF\projects\ccs\proj_lab10a

GMotorVars.OverModulation is set to 0.55. I found that at 30V, the highest duty cycle of PWM reached 96%, and it was running normally, and the speed was also improved. However, when the voltage was 40v, the highest duty cycle of PWM reached 96%, and the speed was also improved, but the operation was abnormal, and it was found that the phase current fluctuated and there was abnormal noise.

1. Ask if the configuration of what is interrupted is too small, resulting in no time to deal with it. Because 30V, the maximum speed is 2300rpm,40V, and the maximum speed is 3000rpm.

2 or the phase current accuracy is not enough,

over 1 year ago

0 Yanming Luo over 1 year ago

TI__Guru** 116120 points

The control algorithm execution time is not related to the input voltage, but the signals noise may be different when the dc-bus is high. When the dc-bus voltage and speed are high, the current and noise will be higher as well. Make sure that the current sensing signals are in the ADC sampling arrange on the board.

0 zhou qicheng over 1 year ago in reply to Yanming Luo

Intellectual 790 points

Hello, the current power supply voltage is 40V,

1. it is found that gMotorVars.Vs is 0.28 at the highest speed, far less than 0.5.

2, USER_MAX_VS_MAG_PU 0.52 motor runs normally, and the speed of 0.53 increases, but there is abnormal noise. Why is this?

0 Yanming Luo over 1 year ago in reply to zhou qicheng

TI__Guru** 116120 points

Any load did you add on the motor? Can you try to run the motor without load or with a light load to see what happens?

zhou qicheng said:
but there is abnormal noise. Why is this?

Do you have any current waveform measured by the current probe to show the issue? What do you mean the abnormal noise that is measured on the ADC input?

0 zhou qicheng over 1 year ago in reply to Yanming Luo

Intellectual 790 points

Hello, the forum seems to have mentioned that there is a bug with over modulation,

It is said that the duty cycle is full, and the next cycle will start from 1. It is necessary to write 0 or something before entering. Now this post cannot be found, is this phenomenon happening? How to change

0 Yanming Luo over 1 year ago in reply to zhou qicheng

TI__Guru** 116120 points

Your own board? Or TI EVM board you are using?

zhou qicheng said:
Hello, the forum seems to have mentioned that there is a bug with over modulation,

What do you mean this? The overmodulation and current re-construction is sensitive to current sensing signals.

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TMS320F28027: overmodulation