High-performance line conditioner with output voltage regulation and power factor correction

A high-performance line conditioner with excellent efficiency and power factor is proposed. The line conditioner consists of a three-leg rectifier-inverter, which operates as a boost converter and a buck converter. This boost-buck topology enables constant output voltage regulation, irrespective of input voltage disturbances. In addition the three-leg bridge can reduce the number of switching devices and system loss, while maintaining the capabilities of power factor correction and good output voltage regulation. The power factor controller for the single-phase pulse-width modulated (PWM) rectifier is derived using the feedback linearisation concept. The inverter side acts as a voltage regulator with current-limiting capability for impulsive loads. The disturbance of input voltage is detected using a fast-sensing technique. Experimental results obtained on a 3 kVA prototype show a normal efficiency of over 95% and input power factor of over 99%.