Novel multi-mode active power quality conditioner for series voltage compensation

A novel multi-mode active power quality conditioner (MAPQC) for series voltage compensation is proposed. In the MAPQC, an improved single-phase full bridge circuit is developed to perform both flexible compensation of line voltage and crucial energy balance at DC side. Moreover, two small backup batteries are implemented to smooth temporary voltage fluctuation at DC side; hence the actions of the pulse width modulation (PWM) rectifier are efficiently reduced. The control signal is directly derived from the instantaneous voltage value of ac mains without processing harmonic frequency. Thus the MAPQC can work in simple open-loop state, which ensures high-speed and precise response to harmonic voltage distortion and load voltage excursion. Compared with previous methods, this scheme is simpler and more economical in practice. Operation principles and realization of the new MAPQC are discussed in detail. Experimental results obtained from a 2 kVA prototype show that it has good performance in quality power supplying applications.