SVPWM and ePWM Switching pattern, BLDC Sensorless Parameter Estimation.

Dear Community,

I am refering https://in.mathworks.com/help/mcb/gs/sensorless-foc-pmsm-smo-fo.html example for BLDC Sensorless application.

As It uses PWM referance Generator block.for duty cycle generation. I am trying to generate 6 PWM waveform which will drive 6 MOSFETs.

I have following queries.

1. I am trying to understand how it will create Switching Pattern to drive MOSFET circuit.
2. What is deadbad between each ePWM when transition from one sector to another sector(Eg. U1 to U2 and till U6.) How to check and how we can change to avoid short circuit in MOSFET?
3. Any referance can you share for BLDC Sensorless Parameter Estimation?

Thanks.

Answer 1

[Kothuri]

Hi Bhagyesh,

• For generation of 6 step switching pattern, you can use the "Six Step Commutation" block to generate switching sequence for six-step commutation of brushless DC (BLDC) motor. You can refer the below documentation link on "Six Step Commutation" block

https://www.mathworks.com/help/releases/R2024a/mcb/ref/sixstepcommutation.html

• To check and change the deadband, open the "ePWM" block and navigate to "Deadband Unit" and enable "Deadband generation".
• You can refer the below documentation link on Sensorless control of BLDC motor.

https://www.mathworks.com/help/sps/ug/bldc-sensorless-control.html

[Bhagyesh]

@Kothuri: Thanks for your answar.

1. https://www.mathworks.com/help/releases/R2024a/mcb/ref/sixstepcommutation.html : Block uses Hall/Encoder as position feddback. But in my application It is a BLDC Sensorless motor. In above mentioned example it uses PWM referance Generator block.for duty cycle generation. How it will create Switching Pattern to drive MOSFET circuit.
2. I understand deadband can be generated for individual ePWM phase. How to check deadbad between changing from one space vector to another space vector.(from U1 to U2 etc.)
3. Can you share referacne example for BLDC Sensorless Parameter Estimation?
4. https://www.mathworks.com/help/sps/ug/bldc-sensorless-control.html Can we use this for TI LAUCHPAD F280049C code generation?

Thanks,

Bhagyesh