Modeling And Simulation Of Three-phase Grid-connected Inverter Based On FPGA

Three-phase grid-connected inverter is an important link between the new energy generation system and the power grid,and plays an important role in the whole new energy generation system.In order to realize the semi-physical real-time simulation of three-phase grid-connected inverter,this paper studies the real-time simulation modeling method and semi-physical real-time simulation platform.The main work is as follows:At first,this paper studied the modeling method of power electronic systems,in power electronic system with the change to the whole simulation system of switch state brings a large amount of computing problems,studied the method of separation of continuous and discrete model to establish the operation mode of the model of three-phase grid inverter is independent,the method avoids the switch action leads to model equation of the whole system update,reducing the amount of calculation;For the equivalent method of the switching device,the switching function method is selected to establish the equivalent model of the switching device.Aiming at the problem of the limited simulation accuracy of the traditional switching function,an improved switching function method considering the influence of switching voltage loss and dead zone time is proposed to improve the simulation accuracy of the model.For the continuous circuit,the state variable analysis method is used to establish the model and the numerical integration algorithm is used for discretization processing,and the correctness of the established real-time simulation model of three-phase grid-connected inverter is verified.Secondly,the design method based on the model of the System Generator was adopted to realize the real-time simulation model of thethree-phase grid-connected inverter based on FPGA simulation,and the solver design of the state space of the switching device part and the continuous circuit part was carried out in the System Generator respectively.First using Simulink complete three-phase grid inverter primary simulation,then the primary control unit of the simulation of unchanged,and based on the System of the Generator to realize electronic circuit real-time simulation model of three-phase grid inverter closed-loop hybrid simulation together,will be the primary simulation results compared with hybrid simulation is verified based on the System of the Generator set three-phase grid inverter power electronics part of the model is correct,The conversion of the power electronics model of the three-phase grid-connected inverter based on the System Generator to the FPGA was realized by means of automatic code generation.Finally,set the semi-physical real-time simulation platform,the open loop and closed loop control algorithm,and the semi-physical real-time simulation results compared with Simulink simulation results,see from the simulation results that both the waveform of high consistency,the error is small,which proved the practicability of semi-physical real-time simulation platform and established based on FPGA is the effectiveness of the real-time simulation model of three-phase grid inverter.The hardware-in-the-loop real-time simulation platform built in this paper can provide a good test platform for the research and development of the control algorithm of the grid-connected inverter.