Hi, I've gotten a little confused and would like some guidance and confirmation,(adsbygoogle = window.adsbygoogle || []).push({});

I've designed an H-Bridge inverter which should output 100A at 20Vrms onto a 200mΩ load. The current target output peak voltage (with max duty cycle of 98% considered) is 28.86V. The LC filter is made up of a 1500μF Cap and a 60μH L with a Fc of 531Hz, the fundamental is 50Hz, switching is 16KHz.

I'm trying to calculate what compensations (if any) will I need to make to the output peak voltage from the H-Bridge for losses in the filter to ensure 20Vrms is outputted from the filter.

I've found the following calculation but I'm a little confused from its results,

Xc=1/2*pi()*f*C= 1/2*pi()*50*1.5E-3 = 2.4485Ω

Xl=2*pi()*f*L = 2*pi()*50*60E-6 = 53.0516Ω

Z=sqrt(R^2+(Xl-Xc)^2) = sqrt(0.2^2+(53-2.4)^2) = 50.6Ω

I=20Vrms/50.6 = 0.395A

Vlc=I*(Xl-Xc) = 0.395*(53-2.4) = 19.99V

1) Should the frequency in the reactance calcs be the fundamental or the switching?

2) Is I in this case the current through the LC network?

3) Would this result indicate that no or little alteration would be needed to the peak voltage for switching as the voltage across the network is the output voltage?

Many Thanks in advance,

Dale

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# LC Filter Voltage Drop Considerations

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