Research On Robust Control Strategy Of Buck-Boost Converter System

In recent years,with the development of intelligent power grids,distributed power generation and energy storage require fundamental transformation of traditional power generation,transmission and distribution systems.Therefore,power electronics and its control have become a hot spot in the field of converters.As an important part of power electronics,DC-DC converters have been popularized in industrial occasions such as renewable energy and electric power due to their simple circuit topology and low cost advantages.As the market demand for Buck-Boost converters is increasing,the control algorithm of Buck-Boost converters has also become a research hotspot.In order to control the output voltage of the converter and ensure that the output voltage of the converter can be maintained within the expected output range,this paper designs an adaptive sliding mode controller with unknown resistance load,a passive controller with a resistance load,and Differential passive controller with ZIP load.The main work is summarized as follows:(1)An adaptive sliding mode controller based on the Luenberger observer is designed,which eliminates the influence of the uncertainty of the load parameters in the circuit system on the output voltage characteristics,and achieves the goal of stabilizing the output voltage at the desired output voltage.Finally,the feasibility of the controller is verified by simulation.(2)The theory of passivity is used to analyze the converter system from the energy aspect and design a passive controller.The dynamic performance of Buck-Boost converter system is improved by optimizing the energy transfer mode,and the output voltage is stabilized at the desired output voltage.Finally,the feasibility of the controller is verified by simulation.(3)Based on the theory of differential passivity,a state feedback differential passive controller is proposed by establishing the augmentation system of Buck-Boost converter.At the same time,based on the method of parameter estimation,a current observer is designed to estimate the inductance current online,which solves the problems of the high cost of measuring the inductance current with the current sensor in the practical application of the converter and the complexity of the load in the microgrid environment,and achieves the stability of the output voltage at the desired voltage.Finally,it is strictly proved that the closed-loop system is globally asymptotically stable,and the feasibility of the proposed controller is verified by simulation study.