Stability Analysis And Improvement Of Two Kinds Of High-order DC-DC Converter

With the development of switching power supply technology and the requirements for power supply and load characteristics,higher-order DC-DC converter topologies have become more and more widely used in photovoltaic power generation systems,aerospace systems,and computer communication systems.All along,its stability is the most concerned issue in the industry,so it is necessary to analyze and study its stability to meet the increasing technical requirements.This article mainly analyzes the stability of the converter system from two aspects.Firstly,the optimization method of damping design for high-order DC-DC converter controlled object is summarized,and it is applied to the topology of Superbuck and Superboost converters widely used in avionics system,the linear method is analyzed and a damping circuit design method is proposed.On the other hand,the input impedance of the converter also has a certain influence on its stability.Generally,the intersection with the output impedance can be reduced by increasing the amplitude of the input impedance.This paper proposes a double-loop control method with the average input current loop as the inner loop and the output voltage loop as the outer loop,which effectively increases the input impedance of the converter and analyzes the factors that affect its amplitude at this time.Based on the above theoretical analysis,the simulation design of the damping loop design method and the double-loop control method proposed in this paper was performed using PSIM software.The results show that the damping circuit design method can effectively avoid the right half plane(RHP)zero in the transfer function of the plant controlled object,thereby reducing the instability of the converter system.Under the given double-loop control method,when the cutoff frequency of the current loop is higher than the cutoff frequency of the voltage loop,increasing the current sampling coefficient can increase the gain of the current loop,thereby increasing the input impedance of the converter and making the stability of the system improved.