A new PWM controlled AC-DC converter using GTO thyristors

A three-phase current-output-type pulsewidth-modulation (PWM)-controlled AC-DC converter is proposed. The PWM technique is used to obtain sinusoidal input current and unity power factor. The input power factor can be freely adjusted, and bilateral energy flow is possible. A unique method is used to control the output voltage. It is shown that the resonance problem can be solved by the proper selection of input filter and PWM pattern. The steady-state characteristics of the converter are analyzed by the state-variable method, and experimental results are shown.<<ETX>>