A Novel Circuit Topology of Three-Phase Direct AC-AC PWM Voltage Regulator

Recently, a new generation of ac-ac single-phase and three-phase power converters with more commutations per half cycle has been proposed for ac power or ac voltage conditioning due to the increasing availability and power capability of high frequency controlled-on and off power semiconductor switching devices. This paper presents a novel simple circuit topology of symmetrical PWM ac line conditioning circuit for three phase power systems. The converter topology uses a minimal number of controlled power semiconductor switches and features buck voltage capability. This ac-ac power converter is seen to be an ac voltage regulator with output voltage range of 0-1 p.u. with reasonable current and voltage waveforms. The operating principle and the operation modes of the proposed three-phase direct ac-ac power and voltage conditioner are described and evaluated through a design example based on analytical expression and simulation results.