The Research And Design Of Photovoltaic Grid-Connected Micro-Inverter

Nowadays, with the decreasing of fossil energy sources and the aggravating of worldwide environment, low carbon and energy saving have become the theme of social development in the future. Therefore, the development of photovoltaoc power generation technology and utilization of solar energy resource in response to fundamentally salve the energy and environment problems are of great significance.In order to achieve the maximum utilization of solar energy and improve the efficiency of photovoltaic power generation system, a new photovoltaic grid-connected micro-inverter is designed. The main work and achievements in this paper are as follows:(1) This dissertation analyzed the principle, research status and application of key technologies of photovoltaic grid-connected micro-inverter.(2) The structure of photovoltaic grid-connected micro-inverter is designed, the main circuit topology and control scheme of inverter are given. Based on the principle and characteristic analysis of interleaved flyback inverter, a new segmented hybrid control methed is proposed, the leakage inductance energy absorption circuit and scheme of zero voltage switching are designed for the interleaved flyback inverter. In order to improve the stability of the output sinusoidal current of inverter, the grid-connected current control strategy is proposed, and the quasi proportional resonant current controller is designed. The simulation results verified the feasibility and effectiveness of the proposed control method and strategy.(3) According to the photovoltaic grid-connected micro-inverter operation parameters and the selection of circuit topology, the main circuit’s tranformer and filter, isolated device circuir and signal sampling circuit are completed.(4) The control system based on DSP is designed, then the working process of DSP control system, maximum power point tracking control and digital phase lock loop control are given. (5) The photovoltaic grid-connected micro-inverter prototype is manufactured, and the operation conditions of prototype are tested, the results indicate that the experimental prototype is operating properly, and the performance of the prototype has reached the design requirements.