Performance Enhancement of Three-Phase PWM Rectifiers Using an Intelligent Fuzzy Direct Power Control Strategy
Many companies use three-phase Pulse Width Modulation (PWM) rectifiers in modern power conversion systems. Some examples where they are used are new energy interfaces, charging stations for electric cars, and complex industrial drives. This is because it can control the flow of voltage on the DC link. Even more important, it can keep the power clean. Due to simple structure and fast dynamic, the conventional control strategy based on the Direct Power Control (DPC) principle is preferred. Due to the variable switch frequency, high power ripple, and power input, classical DPC has several drawbacks. The total harmonic distortion (THD) of the current is high, which limits the rectifier's ability to work in some applications. An intelligent Fuzzy Logic–Based Direct Power Control (FDPC) strategy is proposed to control the three-phase PWM rectifier as a solution to the aforementioned problems. The main goal is to keep the DC-link voltage steady, reduce the harmonic distortion of the current, and keep the power factor at unity under both steady-state and dynamic conditions. In the proposed FDPC strategy, the hysteresis comparators and switching table are replaced with a fuzzy inference system, which takes the active power error, reactive power error, and grid voltage vector position as inputs and produces an optimal voltage vector selection as an output. The FDPC scheme is implemented and investigated through MATLAB/Simulink and Fuzzy Logic Toolbox. Simulation results illustrate that the proposed controller shows significant improvement of system performance over conventional DPC. The DC-link voltage follows the reference value with fast dynamics response and smaller ripple. Moreover, the input current THD is reduced from 4.78% to 1.93% which meets IEEE 519 requirement, and the reactive power is also regulated to zero for near-unity power factor operation. The simulation results validate the robustness of the proposed FDPC strategy for high-performance PWM rectifier in applications with high power quality requirement.