Research On10KW Three-phase Photovoltaic Gird-connbcted Inverter

The coal, oil, natural gas and other fossil energy with the development andutilization is resulting in the pollution of environment, in addition the primary energy isbecoming less and less.The development of clean new energy has be imperative.Solarenergy is resourceful, potential, no pollution.In the future, it will be the importantenergy.The countries in the world pay attention to the photovoltaic technology, and thephotovoltaic grid-connected inverter is the main direction of research.With the rapiddevelopment of digital signal processing chip,DSP makes the control algorithm ofphotovoltaic grid-connected inverter can be realized. In this paper, the control chip isTMS320F2812, and the object of study is10KW photovoltaic grid-connected inverter.Firstly,this paper analyzes the background and development situation at home andabroad of photovoltaic grid-connected inverter, then outlines the compositionclassification, and topological structure of photovoltaic power generation systems.Secondly,the basic working principle and characteristics of photovoltaic cell areintroduced, and the photovoltaic array maximum power tracking principle and controlalgorithm is analysed by changing the duty ratio of power switch tube to achieve thepurpose of maximum power point tracking.Then,the selection principle for the grid-connected inverter were introduced. Onthe basis of several commonly used output current control algorithm,the article focuseson the development and the principle of fuzzy control, through adjusting the width ofhysteresis loop to realize the reduction of switching frequency range.Finally, the10KW three-phase photovoltaic grid-connected inverter is designedand simulated. The main circuit uses DC-DC boost circuit and DC-AC inverter circuit.The control circuit contains the design of the detection, drive and protection circuit. Andthen the photovoltaic grid-connected inverter is analyzed. The simulation results show,the photovoltaic array can quickly response to the maximum power point, the inverteroutput current and power grid voltage is the same frequency and phase, the power factoris1with the tracking speed and less harmonic content.