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TMS320F28027F: Several Issues Regarding SVPWM

user1303469
Intellectual 310 points
Part Number: TMS320F28027F
Other Parts Discussed in Thread: MOTORWARE

Tool/software:

I am comparing the driver made with tms320f28027f with another company's driver and found that the motor noise is louder when using my driver. Then I measured the current waveform and phase voltage waveform of another company's driver, as follows

1：

2： overmodulation

Yellow phase voltage waveform, purple motor current waveform

Question 1     What SVPWM is he using?

Question 2     He also has a current close to a sine wave during overmodulation. My current waveform during overmodulation is a trapezoidal wave, so the noise is loud. How to optimize the current waveform during modulation?

Question 3    His driver can be turned on and off at any time when the motor is running at high speed, and there is no surge current in the motor. How did he achieve this and what method was used when six MOSFETs switched from off state to working state during high-speed operation of the motor, without any surge current in the motor?
I have worked on a gyroscope project before, where it took several hours for the motor to slow down from its maximum speed to 0. When a fault occurs, the IGBT needs to be turned off. When the fault is resolved, the motor needs to be restarted. If the motor is restarted at high speed, there will be a large initial current, which is very unfavorable for the IGBT. The algorithm for starting the motor without any surge current during high-speed operation is very important. Please help me.

  • 0
    TI__Mastermind 23810 points

    Hello,

    Thank you for your inquiry. Can you first define what software kit you are using for this? Are you using motorware?

    Best Regards,

    Allison

  • 0 in reply to Allison Nguyen
    Intellectual 310 points

    I have developed tens of thousands of products based on InstaSPIN. This is an electric motorcycle project.

  • 0
    Expert 1360 points

    Hello,

    I'm not a TI employee but a user as you are and I was just curious about the topic.

    Question 1:

    Sounds like MIN SVPWM

    Question 2:

    I have some issue in the past also with overmodulation, the current reconstruction algorithm is a little bit tricky to tune but it was the key to my issue. At the moment the reconstructed current was fine, the overmodulation was really better.

    Question 3:

    I agree with you. In my application flying start at the origin also create some current. I have change a lot how it works based on some hints you can find in litterature / older topics. Now it is OK but I spent a lot of time to change it. 

    Regards.

  • 0 in reply to Manu36
    Intellectual 310 points

    Question 1: 我查了资料应该时5段svpwm. 

    Question 2: I don't think the current reconstruction provided by Ti official is ideal. How did you handle it?

    Question 3: Can you talk about how you handle the situation where there is no surge current when the motor starts at high speed?

  • 0 in reply to user1303469
    TI__Guru** 115500 points
    user1303469 said:
    Question 2: I don't think the current reconstruction provided by Ti official is ideal. How did you handle it?

    If you want to enable over modulatyion, yes, you have to implement current reconstruction. The current recontrcution is not related to the implementation methos, is also dependent on the current sensing signal. You can find the related documentation on TI websiet or the related technilogy website. The implemetation method is a typical technique.

    user1303469 said:
    Question 3: Can you talk about how you handle the situation where there is no surge current when the motor starts at high speed?

    As mentioned above. The hardware circuit is aslo critical for the current sensing and reconstruction.