Research On Micro Inverter Technology Based On Photovoltaic Power Grid-connected System

With the development of the times,photovoltaic power generation has become an important part of green energy in the new era,and is one of the important means to solve the global energy and environmental crisis.In photovoltaic power generation,the performance and efficiency of inverters have become an important factor affecting the whole photovoltaic power generation system.As a new type of photovoltaic grid-connected device,photovoltaic micro-inverters have attracted the attention of various countries and play an increasingly important role in photovoltaic power generation system.As a developing country,it will be very necessary for us to do in-depth research on micro-inversion technology of photovoltaic grid-connected system.Firstly,this paper analyses the composition of photovoltaic grid-connected system,and considers the main issues to be considered in the design of micro-inverters,such as efficiency,cost,communication,etc.The working principle of photovoltaic array is described,and the simulation module diagram of photovoltaic array is established in Simulink,and the maximum power point tracking technology is improved.The perturbation observation method is used to improve the voltage conversion efficiency and tracking speed of the micro-inverters.The different circuit topologies of the micro-inverters,such as the power nature,power series,single-stage and multi-stage,are analyzed to provide a theoretical basis for further reducing the circuit cost of the micro-inverters.The communication technology in the inverters system is studied.CAN-BUS is used to improve the communication speed and stability of micro-inverters photovoltaic grid-connected system,and the CAN communication protocol is designed.Secondly,the single-phase photovoltaic grid-connected micro-inverters are selected as the design object,and the structure scheme of the micro-inverters is designed,and the design parameters and basis of the system model are put forward.Voltage source two-stage non-isolation transformer is selected as the circuit topology of the micro-inverters to reduce the volume of the circuit board of the micro-inverters and reduce the cost.Through the research on the choice of chip,CAN communication circuit,DC side voltage and current,AC side voltage and current and main circuit,the hardware improvement scheme of the micro-inverters is designed.Then,the simulation experiment of Maximum Power Point Tracking(MPPT)is carried out.The simulation results show that the micro-inverters designed in this paper can quickly convert the voltage and improve the tracking efficiency.The circuit output curves of the designed micro-inverters and LC circuits are obtained by simulation,which verifies this paper.The designed micro-inverters can ensure the normal operation of photovoltaic system while reducing the cost.A CAN test model is built and tested by CANoe,a professional equipment.The test results show that the CAN communication can be applied to the photovoltaic grid-connected power generation system based on micro-inversion technology,and it can be applied to the photovoltaic grid-connected power generation system.Effectively improve communication speed and stability.The above three simulation experiments verify that the micro-inverters designed in this paper can effectively improve the efficiency of photovoltaic grid-connected system,and also show that the research of micro-inverters based on photovoltaic grid-connected system is fruitful.