Research On Power Optimization And Control Strategy Of Photovoltaic Charging Inverter System

Photovoltaic chargers and battery inverters are two types of equipment commonly found in off-grid photovoltaic charging and inverter systems.Thesis takes the household photovoltaic charger and inverter as the research object,and applies the improved particle swarm optimization algorithm to the maximum power point tracking(MPPT)control in the photovoltaic charger,and proposes a hybrid control strategy in the inverter controls for the waveform stability of the sine wave.The research content is as follows:(1)I carry out theoretical analysis and research on the structure of the charging and inverter integrated machine system.The photovoltaic cell is modeled in Simulink software according to the physical structure of the photovoltaic cell.Combined with the content of power electronics,the scheme of photovoltaic charging inverter system is designed and studied.In the photovoltaic charger,a two-phase interleaved synchronous Buck rectifier circuit is used as the main circuit of photovoltaic charging? in the inverter,a push-pull switching power supply is used to convert the low voltage The direct current is boosted,and the H-bridge inverter circuit is used to invert and output the sine wave alternating current.(2)Apply the particle swarm algorithm to the MPPT control of the photovoltaic charger.Aiming at the problems of chaotic initialization,chaotic voltage traversal,and local optimum of the basic particle swarm optimization algorithm in MPPT applications,an improved particle swarm optimization algorithm is proposed by adopting arithmetic array initialization,traversal size and small-big sorting,and exclusion of local optimum..Based on the numerical simulation to track the optimal point of various functions,the results show that the improved particle swarm optimization algorithm is effective and high-precision in finding the optimal point of the function.(3)Aiming at the problem that the sine wave output by the off-grid inverter will be affected by the battery discharge capacity and load characteristics,a hybrid control strategy is proposed to control the inverter.The post-stage inverter model of the inverter is built based on Simulink software,and the hybrid control strategy is simulated by using unipolar modulation.The simulation results show that the sine wave output by the inverter using the hybrid control strategy is stable and the system responds quickly.(4)Based on the improved particle swarm algorithm and hybrid control strategy,design an experimental platform for the control system of the photovoltaic charging inverter system.A two-phase interleaved synchronous Buck rectifier circuit,a flyback power supply circuit,etc.are designed for the photovoltaic charger? a push-pull switching power supply circuit,an H-bridge inverter circuit,and other circuits are designed for the inverter.In order to improve the compatibility of PCB,the control board based on STM32F103C8T6 single-chip microcomputer is designed by adopting the plug-in PCB method.Using algorithms such as Free RTOS system,Kalman filter algorithm and fuzzy PID control,the stability and response speed of photovoltaic charger and inverter operation are improved.The improved particle swarm optimization algorithm and hybrid control strategy are debugged,and the effectiveness of the improved particle swarm optimization algorithm and hybrid control strategy is verified in practical applications.