Research On Control Strategy Of Single Phase Parallel Inverter Power Supply

In recent years,as the global demand for renewable energy sources continues to grow,inverter power supply technology is receiving widespread attention.In order to increase system capacity and improve reliability,multiple inverters are used to form a system that works in tandem with each other through parallel control techniques.However,due to the deviation of the output voltage between each inverter power supply,this can lead to uneven distribution of the output power and cause excessive system loop current problems.Therefore,the study of individual and parallel control techniques is of great importance for inverter power supply.The single-phase full-bridge inverter circuit is widely used in the field of single-phase inverter power supply due to its simple structure,low cost and high DC bus voltage utilization,and the circuit has a high engineering application value.Therefore,this thesis designs a parallel system for inverter power supply based on a single-phase full-bridge circuit.In this thesis,the following research is carried out with the aim of improving the output waveform quality of the individual inverter power supply,achieving power equalization and circulating current suppression of the inverter power supply in the parallel system.From the perspective of the individual inverter power supply,this thesis introduces the operating principle of the single-phase full-bridge inverter circuit,establishes a mathematical model,analyses the double closed-loop control principle in detail and derives the output impedance of the single-phase inverter.Subsequently,the controller parameters and main circuit parameters of the inverter power supply are designed and the steady-state and dynamic characteristics of the system are simulated and analyzed by MATLAB software.From the perspective of the inverter power supply parallel system,a mathematical model of the single-phase inverter parallel system is established and a systematic analysis of the circulating current is carried out in this thesis.Afterwards,two parallel schemes,master-slave control and virtual inductor-based droop control,are introduced.The controller parameters are designed and the power equalization effect and the circulating current suppression effect of the two schemes are simulated and validated by MATLAB software.Finally,the main circuit of the inverter parallel system and the control circuit based on the TMS320F28035 DSP are designed and an experimental prototype is built to experimentally study the individual control and master-slave parallel control of the inverter power supply.The experimental results verify the feasibility and effectiveness of the theoretical scheme.