PERFORMANCE EVALUATION OF THREE PHASE SCALAR CONTROLLED PWM RECTIFIER USING DIFFERENT CARRIER AND MODULATING SIGNAL

Abstract

Power quality problems caused by significant increase of non-linear loads initiated intensive research in high power factor converters. Most of the modern power electronic systems like variable speed drives, DC power supplies and battery charging systems uses uncontrolled diode bridge rectifier. The uncontrolled rectifier system injects lot of harmonics in to the AC supply system there by reducing the power factor to less than unity. Single stage PWM rectifier is the novel solution to eliminate the harmonics and to improve the input power factor. In this paper, a scalar controlled PWM rectifier is modeled and the system is compared with the conventional bridge rectifier with and without filter.The major advantages of using this technique are less intensive computational control and sensor less input voltage operation. The PWM rectifier system is investigated using the different carrier and modulating signal. The scalar control technique is used to control the boost rectifier output voltage and input power factor. The performance of the rectifier with different carrier and modulating techniques were compared with respect to the Total Harmonic Distortion (THD) in source current. Simulation results demonstrate the effectiveness of the modified modulating signal and triangular carrier signal for effectively reducing the source current THD.

Keywords

• Scalar control
• PWM rectifier
• Power quality
• Power system harmonics
• Pulse width modulation converters