Research On Single-stage DC-DC Converter Using Active Filter To Suppress Low-Frequency Pulsating Power

With the development of power electronic technology,various nonlinear loads have higher and higher requirements for the performance of power supply.When the load is in the form of pulsation,it will cause voltage and current fluctuations in the system,which will have an impact on other electrical equipment and power supply.In this paper,the control strategy to suppress the fluctuation of output voltage and input current caused by pulsating load is analyzed under a pulsating load condition.A buck-boost bidirectional converter is selected in parallel at the output to provide pulsating power in the output power.The main circuit boost converter adopts voltage and current double closed-loop control,and the inductive current of the active filter is controlled to be equal to the AC current in the output current to suppress the voltage and current fluctuation of the main circuit.At the same time,the volume and quality of the capacitor can be reduced by increasing the voltage ripple of the capacitor in the active filter.The design method of the energy storage capacitor and inductor of the active filter is given in this paper.Then,in this paper,the effects of various control strategies of main circuit and bidirectional converter on the performance of pulsation suppression are analyzed and compared.For the control of inductive current of active filter,a PIR control strategy with an analog resonant controller is proposed based on the traditional PI control method.The resonant frequency of traditional analog resonant controller is fixed,to solve this problem,an adjustable analog quasi-resonant controller is designed based on variable inductance technology.The basic principle of variable inductor is analyzed,and the principle analysis and design process of adjustable analog resonant controller are given.A 150 W DC pulsating power supply prototype based on active filter is built,whose pulsating frequency is among 100～300Hz.The experimental results verify the feasibility and effectiveness of the proposed PIR method.At the same time,an analog adjustable quasi resonant controller based on variable inductor is built.The experimental results show that the resonant frequency of the controller is adjustable,and the performance of the adjustable analog resonant controller is tested in the experiment.