Three-Phase PWM Rectifier Operating Under Different Voltage Conditions

In this book, a proposed control strategy is presented to improve performance of PWM boost type rectifier when operating under different supply voltage conditions (balanced, unbalanced, and distorted three-phase supply voltages). The proposed control strategy is divided into two parts, the first part is voltage controller and the second part is current controller. In the voltage controller, Repetitive Controller (RC) is used to reduce even order harmonics in the regulated output dc voltage, so small output capacitor (filter) is used instead of large capacitor. RC also reduces even order harmonics which appear in the reflected dc current (IMAX), this leads to reduce odd order harmonics which appear in the input currents. While in current controller, Enhanced Phase Locked Loop (EPLL) is used to obtain sinusoidal and balanced three phases, to construct reference currents, which are in phase with the fundamental supply voltages. Therefore, supply-side power factor is kept close to unity. A proportional controller is used to give excellent tracking between line and reference currents. Complete system with the proposed control strategy are simulated using MATLAB/Simulink.