Research On Three Phase Grid-connected Inverter With Feedforward Repetitive Filter

As the energy crisis is extraodinary serious now,it has been emergent to develop new energy and improve the utilization of current power source.There is a mass of power stored or wasted during industrial production,it's very promising to translate this part of power to the grid during distributed generation system. This paper represents analysis of three phase grid-connected inverter used in distributed generation, a system scheme is proposed to reduce the harmonic distortion of the grid currents.The development of distributed generation is introduced first,it's widely used in the industrial energy feedback area. Standard for interconnecting inverter with grid and difficulties in the research of grid-connected inverter is analyzed. In this work, topologies and principles of three phase grid-connected inverter are introduced, the filter interfacing between inverter and grid is of great inportance to the whole system, characteristics and design methods of several filters are analyzed. The structure of the circuit and filter is designed.This paper put emphasis on the control schemes of three phase grid-connected inverter. Several commonly used grid current control schemes are discussed, and the control system of the grid-connected inverter is designed based on the design requirements. Simulation of the inverter is finished and digital control scheme is proposed.A 10kW prototype is made to verify the design, the design of the circuit and digital control platform is discussed. The performance of the three phase grid-connected inverter is tested under different conditions, the proposed system scheme is proved to be practical and effective by the experimental results.