Single-Phase to Three-Phase Power Converter With Reduced DC-Link Voltage Ripple and Grid Current Harmonics

摘要

This article presents a control technique to improve the power quality and performance of grid-connected single to three-phase power converter. The conventional five-leg (5L) topology is modified to parallel five-leg (P5L) topology that has fault tolerance capability and operates even either of the front end converter leg is open-circuited. In such topologies, lower order harmonics (3rd, 5th, 7th, 9th, 11th, 13th, and 15th) are dominant, which are eliminated using a proportional plus resonant controller in the inner current control loop of active front end converter (AFEC). The control technique implemented over single-phase AFEC controls the dc-link voltage and provides unity power factor operation at the grid side and also balances the individual capacitor voltages (V _c1 and V _c2 ) even under faulty conditions of power semiconductor switches. The dc-link voltage oscillation is the inherent problem of such converters, therefore, it is proposed to use advanced bus clamp PWM technique at the inverter side to reduce such ripples and also improves the inverter output voltage profile. The comparative improvement under operating conditions is presented through the simulation and verified on hardware setup to validate the efficacy of the control algorithm.