Abstract
This paper deals with a novel type soft switching PWM power frequency AC-AC converter using bidirectional active switches or high frequency PWM controlled cyclo-conversion circuit, which can directly convert utility frequency AC (UFAC, 50 Hz/60 Hz) power to high frequency AC (HFAC) power ranging more than 20 kHz up to 100 kHz. A novel soft switching PWM prototype of high frequency multi-resonant PWM controlled cyclo-converter using bidirectional IGBTs composed of antiparallel one-chip reverse blocking IGBTs manufactured by IXYS is based on the soft switching resonant with asymmetrical duty cycle PWM strategy. This direct power frequency converter as high frequency cyclo-converter has some remarkable features as electrolytic capacitorless DC busline link topology, unity power factor correction and sinewave line current shaping, simple configuration with minimum circuit components and low cost, high efficiency and downsizing. This series load resonant power frequency cyclo-converter, incorporating bidirectional active power switches is developed and implemented for high efficiency consumer induction heated food cooking appliances in home uses. The basic operating principle of the proposed soft switching PWM high frequency cyclo-converter using the switching mode piece wise linear equivalent circuits, along with some unique features. In addition to these, its operating performances as soft switching operating ranges and high frequency effective power regulation characteristics are illustrated and discussed on the basis of simulation and experimental results