Parameter adaptive secondary ripple voltage compensation for single-phase PWM rectifier control system

In this paper, a secondary ripple voltage compensation strategy for a control system based on a single-phase PWM rectifier without LC filter is proposed. Firstly, the expression of the double frequency voltage on the output side of the single-phase rectifier is derived according to the power conservation, and a feedback channel for voltage sampling on the output side of the voltage controller is designed. Secondly, the optimal feedback gain for the second harmonic voltage under ideal conditions is derived, and the influence of related parameter variations on control performance is analyzed. Subsequently, a parameter-adaptive feedback gain adjustment method based on disturbance observation is proposed, and a control algorithm is designed. Finally, the correctness and effectiveness of the proposed control strategy are verified through simulation. The simulation demonstrates that the control system maintains a good compensatory effect even when the capacitance parameters change. When the capacitance parameters are reduced by 40%, the proposed method achieves a grid-side current THD of 3.38%, compared to 4.26% with the traditional method. In the future, we will continue to investigate this work at low switching frequency.