Research On Parallel Control Technology Of High-power Single-phase Inverter

With the rapid development of society and economy today,ever-changing social changes are increasingly demanding for inverters.The capacity of the inverter power supply required by the project is constantly increasing,and at the same time the reliability of the inverter work must also be ensured,so the inverter parallel technology needs to be developed.In the fields of uninterrupted power supply UPS,energy storage batteries,new energy and trains,and ship power supply,inverter parallel technology has emerged and it has gradually been widely used.First,this paper studies single inverter and establishes the mathematical model of singlephase inverter.The controller selects quasi-proportional resonance(QPR).The control structure selects the inner loop of the instantaneous inductor current and outer loop of the instantaneous voltage value based on the load current feed-forward compensation.and the inner loop.Output voltage instantaneous value outer loop double loop control strategy.Simulation results show that a single inverter can output a standard voltage waveform under any load conditions,and its dynamic tracking is fast and the steady-state accuracy is high.Then,this paper focuses on the parallel control strategy of multiple inverters.According to the parallel mathematical model of the inverter and the circulation formula,the circulation flow is deeply analyzed.Then the traditional PQ power droop control method is elaborated and improved..Taking into account the influence of the equivalent output impedance of the inverter,an improved droop control strategy based on virtual impedance is proposed.Simulations verify that the proposed control strategy can well suppress the circulation between parallel inverters.Finally,this paper carries on prototype experiment,details the main circuit design,control circuit hardware design and control circuit software design,and the key technologies involved in the process of building the prototype.The experimental waveform well verified the correctness and effectiveness of the single-inverter control strategy and the parallel inverter control strategy.