Single-phase Z-Source inverter: Analysis and Low-frequency Harmonics Elimination Pulse Width Modulation

Theoretical analysis and experimental tests indicate that single-phase full-bridge Z-Source inverter, compared to its three-phase counterpart, suffers greatly from low-frequency output harmonic distortion due to the 2nd harmonic component of the current drawn by the inverter bridge from the DC side. Analytic relationship between low-frequency capacitor voltage and inductor current ripple factors and Z-Source network parameters of single-phase Z-Source inverter under Simple Boost Control is derived in this paper. In addition, one novel Low-frequency Harmonics Elimination Pulse Width Modulation technique is presented, which could greatly reduce low-frequency capacitor voltage ripple for given Z-Source network. The theoretical analyses and proposed modified pulse width modulation technique have been confirmed by computer simulation and laboratory-implemented prototype.