The DC-link capacitor current in pulsed single-phase H-bridge inverters

In case of controlling a pulsed single-phase H-bridge inverter with two and three voltage levels the capacitor currents in the DC-link circuit are calculated analytically. For these calculations first a sinusoidal modulated voltage and sinusoidal current at the output of the inverter are presupposed. Afterwards the additional load of the DC-link capacitors caused by harmonic currents of the output filter circuit is examined. For this reason the individual harmonics of the DC-link current with sinusoidal and with overlaid harmonic output currents are calculated with help of spectral analysis. At last the influence of the switching processes to the DC-link circuit load is discussed. The theoretically determined currents in the DC-link capacitors are compared with several practical measurements