The Research On Design And Control Of 3kW SiC Power Device Photovoltaic Inverter

New energy power generation is a hot topic in today’s society.With the increasing depletion of fossil fuels,photovoltaic power generation is undoubtedly a good alternative to energy.Photovoltaic inverter is an important part of photovoltaic power generation,which undertakes the grid test of converting the DC power from photovoltaic array to AC power.At the same time,the efficiency and performance of photovoltaic inverter is very important for photovoltaic power generation system.Efficient and stable inverter can convert more solar energy into electrical energy and generate power stably and continuously,which is very helpful for energy conservation and emission reduction construction of environmental protection energy system.In the first chapter,the social value and current situation of photovoltaic power generation are described,as well as the classification of photovoltaic power generation system.The characteristics of SiC MOSFET,a new wide band gap device,and its application prospect in the field of photovoltaic power generation are introduced.Finally,the research content and significance of this paper are explained.In the second chapter which introduces the classification of photovoltaic cells and analyzes its principle.Combined with the characteristics of photovoltaic cells,the MPPT method is introduced to maximize the power generation efficiency.The disturbance observation method is a commonly used MPPT method,but there are problems of slow tracking and tracking error.Through the comparison of a series of MPPT methods,an MPPT method based on irradiation change is obtained.In the third chapter,the device selection and design are carried out for the front-end boost.For the photovoltaic inverter in small power section,the inverter industry tends to adopt the full bridge topology for design.The full bridge topology has good stability and less power device consumption.In this paper,the H4 full bridge topology is analyzed and the working principle of frequency doubling modulation is introduced.At the same time,the hardware design is carried out,including bus capacitance and power At the same time,the magnetic devices are designed to optimize the system performance.In the fourth chapter,the PSIM simulation platform is established to verify the design parameters and build a prototype for testing.At the same time,the control mode of the system is studied and analyzed.The small signal model of MPPT is analyzed.For the system circuit,the transfer function is obtained and the parameters are optimized by studying the voltage loop of the previous step-up circuit and the double loop control of the main topology.At the same time,it is verified by Bode diagram In this paper,through the transfer function analysis and parameter optimization,the Bode diagram is obtained for industrial application.At the same time,it introduces the principle of PLL and analyzes the Costas PLL and the single phase PLL based on sogi.At last,it introduces the reason of islanding effect and general solutions,which need further study.In the fifth chapter,the theoretical loss distribution and the highest theoretical efficiency are obtained by analyzing the system loss.The theoretical efficiency of SiC inverter is up to 98.62%.The function of the prototype is verified by setting up an experimental platform.The Open-loop test ensures that the system can work safely.Then,the closed-loop test is carried out to obtain the grid connection waveform and the overall efficiency of each power section.Through the comparison with the efficiency of traditional inverter,the theoretical efficiency of SiC inverter is obtained With SiC MOSFET,the system has higher efficiency and less energy consumption.