Three-phase four wire voltage controlled AC line conditioner with unity input power factor and minimised output voltage harmonics

The paper presents a new high performance AC line conditioner isolating any configuration of nonlinear loads for three-phase four wire applications. The proposed conditioner is composed of a switch mode rectifier (SMR) and a ROM based sinusoidal pulse width modulation (SPWM) inverter. The three-phase half bridge type SMR operates under voltage mode control. No current sensing is required. The inverter is also a half bridge type controlled by a ROM based SPWM modulator. Preoptimised SPWM control patterns rejecting the effects of DC link voltage ripples and dead times are programmed. Owing to the nature of the three-phase scheme, the voltage imbalance problem between the DC link capacitors can be lessened. High quality three-phase AC outputs can be obtained while nearly sinusoidal input currents are drawn