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Limiting switching frequency of the SPWM for big IGBT´s

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javivi
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Limiting switching frequency of the SPWM for big IGBT´s

Hello dark wizards of firmware Javier here, im trying to use fabulous VESC firmware with 400V IGBTs to drive big motors.

spwm



The IGBTs have a minimum switching on-off time of around 2,5us.

So far im having issues with the SPWM modulation not respecting the minimum times resulting in nasty shortcircuits (IGBTs dont have the time to fully open or close).

Im not talking about the general switching carrier signal, im talking about the minimum pulse width the SPWM creates.



Is there any way of limiting the minimum on-off time via firmware??



Thanks in advance

benjamin
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Currently there isn't, but soon there wil probably be. Starting December I'm going to work on making a 500 kw controller based on the VESC as my day job, and this one will use IGBTs. There will also be IGBT voltage drop compensation, MTPA, field weakening and many other features that will be useful for high power drives.

javivi
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Thats some good news benjamin!.

Thanks for your response, do you think i could get around this changing the "ma" relation between carrier and modulated signal?

Increasing the amplitude of the carrier triangular signal by modifying the counter autoreload value.



 

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