Novel Multicarrier PWM Scheme for a Reconfigurable Single-Phase Inverter to Achieve Manifold Higher Effective Switching Frequency

Abstract

Inverter operation at higher switching frequency brings several advantages. The article presents a novel multicarrier pulsewidth modulation (PWM) scheme along with a reconfigurable single-phase inverter topology. The combination facilitates multiple times higher effective switching frequency (ESF) at the inverter output. The novel reconfigurable topology incorporates additional pairs of series-connected switches in the conventional full-bridge inverter. The proposed PWM scheme uses multiple modified carrier waves to generate gate pulses for the various switches. Consequently, the switches operate in such a coordinated manner that ESF increases multiple times compared to the actual switching frequency of its switches. Thus, the scheme offers several advantages like reduced filter requirements, reduced overall size, weight, and cost. Moreover, the distortion in the output waveforms caused by the dead time is eliminated by a modified dead-time compensation technique, incorporated with the proposed PWM scheme. The proposed scheme is demonstrated here by configuring the proposed inverter topology as an eight-switch topology to achieve four times higher ESF. It is shown through analysis, simulations, and experimental results that in spite of including additional switches, a high-frequency operation can be achieved with a low cost. The proposed scheme may serve as an alternative to using wide bandgap devices, thereby saving cost and efforts.