Control Strategy for Three-Phase PWM Boost Rectifier Operating Under Different SupplyVoltage Conditions

Abstract

In this paper, a proposed control strategy is presented to improve the performance of thepulse width modulation (PWM) boost type rectifier when operating under different supply voltageconditions (balanced, unbalanced, and distorted three-phase supply voltages). The proposed controlstrategy is divided into two parts, the first part is voltage controller and the second part is currentcontroller. In the voltage controller, Repetitive Controller (RC) is used to reduce the even orderharmonics in the regulated output dc voltage so small output capacitor (filter) is used instead of largecapacitor. RC also reduces the even order harmonics which appear in the reflected dc current (IMAX),this leads to reduce the odd order harmonics which appear in the input currents. While in the currentcontroller, Enhanced Phase Locked Loop (EPLL) technique is used to obtain sinusoidal and balancedthree phases, to construct the reference currents, which are in phase with the fundamental supplyvoltages. Therefore, the supply-side power factor is kept close to unity. A proportional controller isused to give excellent tracking between the line and the reference currents. The complete system withthe proposed control strategy are simulated using Matlab/Simulink. The results for the completesystem using repetitive voltage controller are obtained and compared to the results of the system withthe conventional voltage controller (Proportional-Integral (PI) controller connected in series with aLow Pass Filter (LPF)). The results with the repetitive controller show better response and stableoperation in the steady state under different input voltage conditions, as well as in the transientresponse under changing the load condition.