Hopefully? Another 48vdc-240vac Toriod Inverter build.

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poida Guru Joined: 02/02/2017 Location: Australia Posts: 1458	Posted: 10:08pm 16 Jan 2023         KeepIS said   .. 1: Crossover point glitches get worse as the resonating CAP value get larger. .. During most of the 20 ms period of the AC output waveform, the PWM should be seen as a train of pulses, smoothed over by the LC low pass filter. The pulses change little in width as does the output voltage when viewing a narrow part of the output in time. But crossover is different. At crossover the PWM pulse train now should be viewed as a single very short duration pulse in a period of zero output. This pulse delivers full DC supply voltage. It's not a trivial thing to do to a resonant system at zero voltage. The toroid and other parts will be hit with this sharp pulse carrying a very wide range of frequencies and with good power too. It must ring at some frequency after the pulse hits. This is an inherent characteristic of PWM modulating an AC sine output. Somehow near zero voltages need to be produced from very narrow PWM pulses. And at zero voltage there will be increasing gaps between the smallest available pulse widths where no pulse is required.