Simulation of DC Motor Control Strategy for PWM Rectifier with Power Factor Correction

Abstract

Power electronics equipments become more widely used. Unfortunately, the standard diode/Thyristor bridge rectifiers at the input side cause several problems as: Low input power factor, high values of harmonic distortion of ac line currents, and harmonic pollution on the grid. In recent years, the research interest in the area of PWM rectifiers has grown rapidly.  The PWM rectifier offers several advantages such as: control of DC bus voltage, bi-directional power flow, unity power factor, and sinusoidal line current. Many pulse-width modulation (PWM) techniques have been adopted for these rectification devices to improve the input power factor and shape the input current of the rectifier into sinusoidal waveform. The phase and amplitude control (PAC) seems to be the most simple structure and provides a good switching pattern, but the dc offset on input current of the rectifier during transient state deteriorates the control system stability. The current regulating fashion in synchronous frame has the advantages of fast dynamic current response, good accuracy, fixed switching frequency and less sensitive to parameter variations. This project analyzes the principle of PWM rectifier, and presents a unity power factor control method of PWM rectifier. Controller used double closed-loop PI control, which inner uses three-phase input current control method controlled by unity power factor and outer controls the output DC voltage of rectifier. The proposed concept can be implemented with DC motor using MATLAB/SIMULINK software.