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Tool/software:
I am using the C2000 support package in the matlab simulink. I want a 20khz and 0.5 duty cycle. Hence, I have set the TBPRD at 2500 and CMP value at 1250. I have attached my Algorithm image from ADC to ePWM. For ADCAIN3 the output ePWM1 and ePWM4 are blue and pink waveform. For ADCBIN2 the output ePWM2 and ePWM3 are green and yellow waveform. The switch and sign block are used to control the half cycle of Vac reference voltage/signal. The PWM signal is generated based on the digital representation of the analog value read from the input. I am using transport delay to shift the signal from positive half cycle to the negative half cycle as shown in the image attached. The transport delay is set to 0.05 of the time delay. ePWM1 CAU: clear CAD: set. ePWM4 CAU: set CAD: clear. ePWM2 CAU: clear CAD: set. ePWM3 CAU: set CAD: clear. The deadband supposed to be set at 900ns. I have tried to used the deadband however, the duty cycle/width of the PWM only changes. My problem is the waveform yellow ePWM4 and blue ePWM3 are overlapping. How to fix this issue? How to produce the signal at negative half cycle of Vac reference voltage/signal.
Hello Wan,
When it comes to using C2000 Matlab Simulink feature there are sets of FAQ and common examples that could help you:
Is your duty cycle for yellow and green supposed to be 50 percent? Also are you using up-down or up-count mode for time base counter? If you want to avoid shoot-through of the switches, you should use dead-band submodule. Is using deadband changing your duty cycle to be almost 90 percent like in the picture? Deadband should not modfy duty cycle significantly if everything is set up correctly.
Best regards,
Stevan D.
