Research On DC-AC Inverter Systems Based On Finite-time Control Theory

With the power electronics technique developing rapidly,the switching power supply plays a more and more important role in the field of modern industry.As a core part of the power conversion technology,the DC-AC inverter has been widely used in the industry.Therefore,it is of great theoretical and practical value to study control algorithm with good dynamic,stability and anti-disturbance characteristics for the DC-AC inverter.In this paper,advanced control strategies are designed for the single-phase DC-AC inverter from the aspect of the system analysis and controller design,respectively.The research contents of this paper are as follows:Firstly,the working principles and the basic topological structure of the DC-AC inverter are introduced respectively in this paper.The states of the inverter system are described by Kirchhoff's voltage and current law,and then the mathematical model of the system is established based on the state space averaging method.Secondly,for the output voltage control problem of the DC-AC inverter system,a universal active disturbance rejection control using a finite time high-order sliding mode observer is proposed based on the state space model of buck converter.In the presence of various disturbances,uncertainties and unknown states,the lumped disturbance is introduced and estimated by the finite time high-order sliding mode observer in finite time.Then,by means of the lumped disturbance estimation as well as virtual state estimations in finite time,an output feedback control combined with additional feedforward compensation is proposed and a universal active disturbance rejection controller is designed based on the traditional active disturbance rejection control theory.The asymptotical stability analysis of the closed loop system is given in this paper.The MATLAB/Simulink simulations and dSPACE experimental results compared with other two methods are given to illustrate the effectiveness and feasibility of the proposed control method for DC-AC inverter.Thirdly,to improve the characteristics of the DC-AC inverter system,a continuous terminal sliding mode controller based on the finite time high-order sliding mode observer is designed.In order to estimate the lumped disturbance in finite time,the finite time high-order sliding mode observer is designed based on the mathematical model of DC-AC inverter system.By means of the lumped disturbance estimation as well as states estimations,a continuous terminal sliding mode controller is proposed based on the conventional sliding mode control theory.Under the proposed control method,the output voltage of the DC-AC inverter can reach the desired value in finite time.The finite time stability analysis of the closed loop system is given in this paper.The MATLAB/Simulink simulations and dSPACE experimental results compared with another method are both carried out to validate the control performance of the proposed control method for DC-AC inverter.Finally,to further improve the control performance of the DC-AC inverter system,a uniform finite-time control method based on a uniform finite-time observer is proposed.A uniform finite-time disturbance observer is designed to estimate the lumped disturbance in a fixed time.Then,the estimation of the lumped disturbance is introduced in the controller design and a uniform finite-time controller is designed by using homogeneous theory and finite-time control theory.Under the proposed control method,the output voltage of the DC-AC inverter can reach the desired value in a uniform finite time.The uniform finite time stability analysis of the closed system is given in this paper.The MATLAB/Simulink simulation results show that the proposed control strategy obtains better dynamic and static performance even in the presence of various disturbances and uncertainties,which eventually improves the control performances of the DC-AC inverter system.