Research on THD Optimal Control of Three-phase Four-wire VIENNA Rectifier

Magnetic powder core inductors are increasingly used in power electronic equipment due to their characteristics of low loss, high saturation density, uniform air gap, etc. However, due to its nonlinear characteristics, the operation of the inductor in the power factor correction circuit becomes more complicated, which brings certain difficulties to the design of the circuit control loop. This paper studies the influence of nonlinear inductance on the input current THD of the three-phase four-wire VIENNA rectifier, and describes the working characteristics of the nonlinear inductance, and the three-phase four-wire VIENNA rectifier directly realizes the single-phase VIENNA rectifier after physical coupling. The working principle and mathematical model. Based on the traditional voltage loop and current loop double closed-loop control strategy, the current loop is processed in sections, and the feedforward control strategy is introduced to reduce the THD of the input current of the three-phase four-wire VIENNA rectifier and improve the power factor and sum of the converter. efficiency. Through MATLAB/Simulink simulation, the results show the correctness of the theoretical analysis and verify that the segmented control strategy has a significant effect on reducing the current THD of the three-phase four-wire VIENNA rectifier under nonlinear inductance.