Design And Implementation Of Three-phase Inverter Control Based On FPGA

The traditional inverter based on DSP(digital signal processor) builded has some advantages in flexibility of software deisign and complex of calculations, but the speed of calculation would be limitated because of the design of DSP algorithm is based on sequential program. Moreover, the traditional inverter based on DSP builded has a long development period. While the inverter based on FPGA(Field-Programmable Gate Array) builded not as good as the inverter based on DSP builded on calculation and flexibility of software, FPGA’s parallelism charactersitics that makes it very suitable for high frequency, thus it takes great advantage in speed. Besides, the inverter based on FPGA builded has a short development cycle. Therefor, the design for this paper includes as following:Firstly, this paper based on the basic principles of the three-phase inverter and the working mode, then based on the inverter principles of control to design the control block diagram of the inverter. According to the block diagram, the control process can be divided into AD sampling module, Three-phase locked loop control module, the voltage outer loop and current inner loop module, PWM(Pulse Width Modulation) control module.Secondly, Because in this paper, the control of three-phase inverter is mainly to control the voltage and current, the module of the current inner loop and the voltage outer loop control is the main module. In oder to complete this module, this paper should mathematical it, then design the current inner loop and voltage outer loop control system; Due to the input of the voltage outer loop need to be disposed, the voltage needs three-phase locked loop module to deal with it. Besides, the three-phase locked loop can get the voltage’s phase information, so it can be used to control the active power and reactive power; the current inner loop and the voltage outer loop control module and three-phase locked loop module need the digital voltage and current value, therefore this paper needs the AD sampling module to digitize the voltage and current value; the IGBT’s conduction and disconduction deside the inverter’s current and voltage directly, so this paper needs the control of PWM wave module, using the way of the SVPWM to control the IGBT.At last, this paper complete the experiments of the control based on FPGA at the original three-phase inverter based on DSP. Then this paper compares the results of the output of the inverter based on DSP control and the inverter based on FPGA control.