AC/AC PWM converters with high-frequency insulation and minimum number of switches

An AC/AC PWM converter family is presented, which provides excellent input and output performances and high-frequency insulation with a minimum number of switches. Output performances, in terms of control speed and accuracy, are the same of voltage-fed PWM converters. Input performances meet all modern standards (e.g., IEC 555-2) regarding power factor and current distortion limitation. After an analysis of converter operation, a digital control strategy is presented which fully utilizes the converter capabilities in terms of voltage swing and speed of response and also minimizes the need for sensing devices. Design criteria of power and control sections are given and simulated results are reported, showing the actual converter performances in terms of speed of responses, waveform quality and high-frequency transformer utilization