Design Of Single-Phase Full-Bridge Inverter Based On Two-Dimensional Repetitive Control

As the core component of the distributed energy system,the inverter is called "AC router" of microgrid and smart grid,which plays an important role in the use of distributed energy.The characteristic of the output power has a direct impact on the power generation efficiency of the energy system and the quality of the output power.Therefore,the research on the inverter control problem has important practical significance and application value.In order to improve the steady-state tracking performance and disturbance suppression performance of the off-grid energy system,this paper presents an inverter system design method based on two-dimensional model for repetitive control and active disturbance attenuation control.The main research work and innovative points of the paper are as follows.(1)With the analysis of the role of the inverter in the energy system,a mathematical model of the inverter system is established.The main role of the inverter is to achieve energy conversion and to ensure the efficiency of energy conversion and output power quality.An off-grid energy system is equivalent to a voltage source in which the inverter is required to output AC with constant voltage and frequency.As a result,inverter with constant voltage and constant frequency is commonly used,which is actually a sinusoidal reference voltage / frequency signal tracking control problem.In this paper,we first analyzed the role and control characteristics of the inverter in the energy system,and based on that,a mathematical model is built by using Kirchhoff's law.Moreover,a state-space expression of the system is derived.(2)A method of designing an inverter system based on two-dimensional model with repetitive control compensation is proposed.For the inverter system,there are many factors that produce harmonics,and repetitive control can simultaneously suppress the interference of the numerous harmonics signals whose frequency is an integer multiple of the fundamental frequency.The use of inverter waveform distortion repeated features,The structure model of inverter control system based on repetitive control compensation is established.Through repetitive control of repeated'learning',modify the waveform cycle by cycle.and achieve high precision steady-state tracking of periodic reference input signals.The numerical simulation results show that the designed inversion system is robust and stable,and the tracking error can converge rapidly to zero.(3)A method of repetitive control design for inverter system based on equivalent input disturbance is developed.Repetitive control has little effect on aperiodic disturbance.In order to improve the robustness of the inverter system and the quality of the output power,this paper proposes an active control method based on equivalent input disturbance(EID).First,by analyzing the influence of external disturbance on system performance,the EID estimator is constructed,and the influence of disturbance on the system output is estimated in real time.Thedisturbance compensator is constructed by using the EID estimation value,and the control law based on the feedforward compensation of the repetitive control and the active compensation of the disturbance estimation is established.Then,for the inverter system including repetitive controller,feedback controller,EID estimator and compensator,the setting method of repetitive controller,feedback controller and EID estimator parameters is proposed by using Lypunov stability theory and separation design principle.Finally,the simulation results show that the designed inverter system has satisfactory transient performance,steady state performance and disturbance suppression performance.