The Design And Simulation On Small Or Medium Photovoltaic Grid-Connected Inverter

With the growth of economy, the world's environment is deteriorating step by step, the traditional resources are going to be dry up. Development and promotion of new energy is the policies and measures of the majority countries. Assemble power of photovoltaic power generation grid-connected system in the whole world has reached thousands of megawatts (MW) in the past five years. The photovoltaic grid-connected inverter which connects photovoltaic cell and grid is the key and core of the whole photovoltaic power generation grid-connected system.According to the characteristic of photovoltaic cell array and inverter circuits, analysed and compared the topology of inverter in the market at present, then the paper is chosen to use the double-grade system which composed of DC-DC circuit and DC-AC circuit. DC-DC is adopted of Boost circuit, and DC-AC is Full-Bridge circuit. The preceding stage is not only included boosting pressure but also controled the tracking of the maximum power point. After comparred several methods of MPPT, the increament of electric conductance is simulated by Matlab in the paper. As a result the method can be proved to tract the maximum power point rapidly and stably. In the backward stage of inverter control, the paper is analysised the advantages and disadvantages of several common control methods, and simulated the method of feed-forward grid voltage and tracking current by Matlab. This paper is explored the islanding effect of distributed generation system rudimently, analysed its generation and consequence, compared and analysed the islanding detecting method, and simulated the active frequency drift of active detecting by Matlab. From the result of the simulation,we know this method can detect the islanding rapidly. The rockchip is TMS320LF2407 of TI corporation, its powerful function can accomplish the requirement of small or medium nhotovoltaic generation grid-connected system entirely.