Selective Harmonic Elimination in 3-Phase Two Level Inverter with High Switching Frequency

Hi. I have been trying to implement Selective Harmonic Elimination (SHEPWM) in 3-Phase Two Level Inverter with High Switching Frequency using this approach (link: https://www.mathworks.com/matlabcentral/fileexchange/58045-selective-harmonic-elimination-pwm-shepwm-of-two-level-three-phase-inverter).

I feel there is a problem with this approach that it only works for low switching frequencies. For example, for 7 angle control example, this says that using this approach the effective switching frequency will be only 14*f. So, for 50 Hz fundamental frequency, our switching frequency can only be 700 Hz.

My question is how do I apply SHEPWM if I am targeting high switching frequencies like 20 kHz for SiC inverter? Could the same method be used for high switching frequencies like 20 kHz? Thank you so much.

Answer 1

[Joel Van Sickel]

Hello Katherine,

unfortunately, this question isn't about MathWorks tools, but about the theory of SHEPWM. This is a forum specifically for MathWorks questions. That example is made by an external contributor who does not have a relationship with MathWorks. You can send them a message or you can do a deeper dive in research publications to determine the usefulness of SHEPWM.

I will provide this level of feedback with the caveat that you need to validate this statement on your own: the main purpose of SHEPWM is to utilize low switching frequencies. However, there is nothing stopping your from modifying it to use the low frequency modulation of SHEPWM for improving harmonics while utilizing a faster switching frequency, but you have to ask, are there better techniques out there since you have access to much faster devices?