Research On Methods For Improving Power Quality And Efficiency Of Grid-connected Inverter

With fast development of the new energy generation system, the grid-connected inverter as the core part of the new energy generation system, its low efficiency and harmonic pollution problems is more and more seriously. How to improve grid-connected inverter efficiency and power quality has become a hot research point. As the application of grid-connected inverter technology has matured, how to improve grid-connected inverter efficiency and power quality further to solve problems such as the harmonic pollution with existing circuit topology, commonly used power switching devices, mature control strategies and existing energy storage elements has become an important research direction.In this paper, first the topology of three-phase voltage-type PWM inverter is introduced. With three-phase voltage-type PWM inverter control method analysis and modeling, detailed design of main parameters is introduced. A simulation platform and experimental platform of PV grid-connected inverter system is built. The specification is:Vin=200V～400V, Vout=380V, Pin=10kW,fs=18kHz. On this basis, the impact factors of grid-connected inverter power quality and efficiency are analyzed. The causes of its harmonics, harmonic suppression method and method to enhance power factor has made a detailed presentation. Simulation and experimental verification are given. In addition, this paper also introduces the problems and solutions of PV grid-connected inverter system encountered during the experiments dentally. By solving these problems of three-phase voltage-type PWM inverter system performance is improved. The method to improve system power quality and efficiency are verified, too.Finally, this paper give the output current waveform, the output current THD, power factor, efficiency, and other experimental results. The proposed method of improving power quality and efficiency is verified.