Development Of Low Voltage And High Power Grid - Connected Converter

Power electronics technology is a new technology, which based on the electronics technology, electrical technology and automatic control theory. Power electronics can control the electricity with the weak current, and it is the interface of the weak current and the strong current. The automatic control theory is a powerful tool to realize the complex control objective. With the power electronics, the power electronics equipment can convert power and control power. As very important electronics equipment, the research of the grid connected convertor on theory and practical implementation is very important.Grid connected convertor can be applied to renewable energy power generation, such as wind power generation, photovoltaic power generation, reactive power compensation and active power filter (APF) which can compensate the reactive power and filtering the harmonic current of the power grid. In the dissertation, the universal grid connected convertor is constructed, and the convertor is studied with reactive power compensation control algorithm.The simulation model of the grid connected convertor is developed in PSCAD, with Static Var Generator (SVG) Algorithm, the start-up procedure, deblock process and current step process of the grid connected convertor are simulated. The aim of the simulation is to verify the hardware system and software system reasonable, and to analyze quantitatively the electrical parameter and control parameter.In this dissertation, the grid-connected convertor includes hardware system and software system. The hardware system includes electrical circuit section and controller section. The electrical circuit section includes LCL filter, two-level converter. The controller section includes analog circuit module and digital circuit module. The analog circuit module mainly includes power circuit, analog conversion circuit and IGBT driver circuit. The digital circuit module mainly includes digital input and output circuit, serial communicate circuit, digital signal processer circuit. Software system mainly includes Software Phase Lock Loop (SPLL), current decouple control algorithm, capacitor voltage stable control algorithm and SPWM modeling technology. The software system and the control algorithm are realized in FPGA.After simulating and designing of the hardware and software system, the prototype is developed. Based on the prototype, the single pulse experiment, over current protection experiment, startup experiment and current step experiment are carried out. With the analysis of the experimental data, the experiment results and simulation results show that the performance of the convertor can meet the design requirement.