Power quality improvement using integral-pwm control in an ac/ac voltage converter

Power electronic systems generate harmonics. Harmonic attenuation is important in the improvement of power quality. For power control, using specified pulse width modulated (PWM) phase control per cycle of the AC supply reduces the harmonic impact of many AC-to-AC electronic controllers. This paper describes a novel power controller that uses an integral cycle-PWM phase controlled converter with one bi-directional semiconductor switch. The converter does not need synchronization with the supply. The controlling PWM signal is modulated to generate maximum fundamental component and minimum harmonic content of the load voltage and current. The circuit topology presented in this paper diminishes the inherited drawback of using the phase or integral cycle control concept used intensively for electric heating applications. The technique offers the advantages of simplicity and reliability of controlling high power and low harmonic levels. Power injected to the load can be precisely controlled resulting in high conversion efficiency. Published by Elsevier Science B.V.