Implementation of three-level AC/DC/AC converter with power factor correction and harmonic reduction

Abstract

This paper proposes a three-level AC/DC/AC converter. A single-phase double-voltage power factor correction circuit to improve the power quality and provide two capacitor voltages in the input side of the AC/DC/AC converter and a three-level PWM inverter to reduce the harmonic contents of the inverter output voltages for induction motor drive are presented. In the rectifier side, the hysteresis current control (HCC) technique for a half-bridge switching mode rectifier (SMR) is adopted. A control scheme is presented that the line current is driven to follow the reference current which is derived from the DC link voltage regulator, DC capacitor voltage balance compensator, and the output power estimator. Three-level PWM technique for a three-phase PWM inverter system is used to reduce the voltage harmonics. The major advantage for using such strategy is that the blocking voltage of each power device is clamped to half of the DC bus voltage. The high power factor at the input of the SMR and the low total harmonic distortion at the output of the inverter are verified by software simulations.