A PWM GTO current source converter-inverter system with sinusoidal inputs and outputs

Abstract

A current-source-type GTO converter-inverter system with pulsewidth modulation (PWM) techniques is presented. The inverter circuit consists of six main GTOs, two auxiliary GTOs, and three shunt-filter capacitors, and the converter circuit has the same arrangement as the inverter. The system realizes sinusoidal input and output voltage/current by a simple PWM strategy. Two auxiliary GTOs contribute to shaping the inverter output current into the sinusoidal wave, controlling the DC link voltage, and shaping the converter input current into the sinusoidal wave. The PWM pattern in the inverter, the PWM methods, and the DC link voltage control for the converter are explained in detail. The experimental waveforms of the input and output voltage/current are shown when a 2.2 kW induction motor is driven. The input and output characteristics in the DC link voltage control of the converter are given.