Based On The Design Of The Fpga Three-phase Grid-connected Inverter

The paper's background is about the elevator which is used more and more general in modern society, but It has high energy consumption. Design the grid-connected inverter system with FPGA as the controller. The study is focus on how to transform the DC power which is transformed from kinetic energy in the progress of elevator falling to three phase alternating current, and ultimately be injected into the grid to achieve energy feedback, and improve energy utilization efficiency.Because of the grid-connected current from the three-phase inverter is usually with higher harmonic components, and connecting directly into the grid will generate reactive power and harmonic pollution, the international organization has strict requirements to the energy feedback device connected into the grid. In summary, the ultimate goal is to make the inverter with high output DC voltage utilization rate, the harmonic distortion in grid-connected current is small and the phase synchronize with the grid.In the design of power switching devices'modulation, a new discontinuous SVPWM is researched in the paper, comparing with the conventional SPWM, DC voltage utilization can increase 15.4% in this way and comparing with the continuous SVPWM, It can reduce switching power switching device switching frequency and switching losses, and its also has a smaller harmonic distortion. Between the three-phase inverter the output and the grid, LCL filter is designed, It have better performance in filtering high-order current in three-phase inverter output current.To control the grid-connected current, the double loop current control algorithm with capacitive current in inner loop inductor current in outer loop algorithm is designed, Simulation in simulink indicate that the algorithm have good steady-state performance, and fast dynamic response, the grid-connected current synchronize with the power grid. And advanced IPM intelligent module, Hall current and Hall voltage sensors and analog to digital conversion chip ADS7864 with high-speed high-precision are used in the design of hardware to meet the needs of real-time system.FPGAs with high-speed, rich I/O interface resources, and they are more and more used in power control system. In this paper, Cyclone II series FPGA: EP2C8Q208 as the platform to implement the SVPWM control module, the PI control module, and communication interface module between ADS7864 and FPGA in Verilog hardware description language.Grid-connected system simulation by Simulink and FPGA simulation timing diagram show to the design of three phase grid-connected inverter achieve the desired requirements, verify the feasibility of this system design. It can achieve the function of energy feedback, and ultimately improve the energy utilization efficiency.