Simulation and experiment of three-phase voltage SPWM inverter

For the discrete and nonlinear dynamic system of three-phase SPWM inverter, the small-signal dynamic model of three-phase inverter was established with the switching cycle average method and the small signal perturbation method. The DQ model of the inverter under the rotating coordinate system was obtained by using the three-phase rotating coordinate transformation matrix on the basis of the instantaneous reactive power theory. After that, the transfer function from the control variables to output was derived under the DQ coordinates. The parameter design method of PI (proportional and integral) controller with inner current loop and outer voltage loop was also proposed by utilizing voltage and current dual-loop. The simulation and experiment platform were set up and it has been shown through the simulation and experiment that the model is corrective and the parameter design method of the controller is of rationality and validity.