Design Of 1kW AC/DC Electronic Load

Participating in the school-enterprise cooperation project "Development and Construction of Distributed Photovoltaic Power Station Comprehensive Experimental Platform",in order to solve the problem of laboratory power test requirements during the construction of the project,a1 k W AC/DC electronic load composed of GaN power devices was designed.The front stage of the system realizes different load simulations through the control of the input current,and the later stage realizes the measured power source energy to return to the grid through the control method.The AC/DC electronic load has small size,high power density,good test dynamic performance,energy saving and environmental protection,and outstanding advantages.The main research content of this design is divided into the following five aspects :(1)Briefly introduce the definition of AC/DC electronic load,and explain the background of the AC/DC electronic load project.Analyze the current research status and significance of AC/DC electronic load not only main circuit topology design but also controling strategy design at home and abroad.Further clarify the research content and design indicators of the AC/DC electronic load design of this subject.(2)Based on the working principle of AC/DC electronic load,determine the overall framework of the system.It is determined that the system uses back-to-back dual PWM rectifier converters as the main circuit topology.Through the control of the power switch tube,different working modes of the electronic load are realized.Based on the above working modes,the working principles of DC electronic load simulation and AC load simulation and energy feedback are respectively analyzed.(3)According to the design index of AC/DC electronic load,determine the experimental hardware circuit design plan,and complete the energy storage inductor and capacitor design.The main circuit topology circuit power switch device selects a wide bandgap GaN power switch device,completes an optimized design of a GaN power switch device drive circuit,and further solves the problem of misconduction and ringing in the driving process of the gallium nitride power device.Design a GaN Power devices independently source and sink outputs,and overcurrent graded protection gate drive circuit.When the GaN power device has an overcurrent phenomenon within twice the rated current,the GaN power device can be quickly turned off;when the GaN power device has an overcurrent phenomenon that is more than twice the rated current,the GaN power device can be slowly turned off.(4)Based on the voltage-type PWM rectifier model,complete the establishment of the mathematical model of the AC and DC electronic load system load simulation unit and energy feedback unit,and select the current inner loop PI control in the load simulation unit to realize load simulation in different modes,and select the energy feedback unit Voltage outer loop and current inner loop dual PI control to realize DC bus energy feedback to the grid.And its control method realizes its function through software programming.(5)The system simulation model is built through Saber,and the rationality of the AC/DC electronic load design can be verified through simulation.Through the establishment of a 1k W AC/DC electronic load experimental platform,after completing the debugging of the GaN power device drive circuit and the sampling circuit separately,the whole system designed is powered on and debugged.Based on the workload,length of the paper and the limitations of laboratory conditions,this paper mainly completes AC power test simulation and experiment,simulation analysis and experimental verification of resistance-inductance,resistancecapacitance,and constant resistance load to verify the feasibility of the design It can not only complete the load simulation,but also return the energy of the tested power supply to the grid.