Cascaded H-bridge power carrier communication method based on harmonic injection

Scaded H-bridge inverter systems are widely used, but there are complex communication problems between multiple module communications. In this paper, a power carrier communication method injecting the third harmonic is proposed for a single-phase cascaded H-bridge system. The third harmonic is superimposed on the SPWM sinusoidal waveform as a modulating signal and demodulated from the acquired current signals by means of DQ conversion. The baseband input signals are directly observed from the Id and Iq signals. There is no need to add additional communication lines. The method is simple and reduces costs.