The Research And Implementation Of SVPWM System Based On FPGA

With the rapid development of power electronic technology, the technology of AC frequency conversion has also made remarkable progress. Space Vector Pulse Width Modulation (SVPWM) has the advantages of low harmonic content, small torque ripple and high voltage utilization efficiency by controlling the voltage space vector to form an approximate circular flux vector. It is a superior speed control technology. FPGA has the advantages of low power consumption, fast speed, high flexibility, short development cycle and so on. Therefore, using FPGA to realize SVPWM can effectively improve the operation speed and applicability of the system.Firstly, the principle and design method of SVPWM control are introduced. According to the different position of zero vector insertion, the advantages and disadvantages of seven-stage and five-stage pulse width modulation are described. The harmonic content of 7-segment modulation method is small but the switch frequency is more, and The harmonic content of 5-segment modulation method is more but the switch frequency is small. In order to make the harmonic content as little as possible, 7-segment modulation method is selected. Secondly,the single-mode overmodulation algorithm is analyzed. The algorithm is simple and easy to implement, but it is lost part of the fundamental voltage and can not reach the state of six-step ladder wave. In order to improve the shortcomings of the single-mode overmodulation algorithm, a doublel-mode overmodulation algorithm is adopted. The overmodulation algorithm compensates the fundamental of the output voltage, and the system can smoothly transition from the linear modulation region to the six-beat ladder wave state. Then, the design of the top file of SVPWM control system is completed by using the top-down method, and the modules and the whole control system are simulated with Modelsim. The simulation results are in agreement with the theoretical analysis.Finally, the FPGA-based SVPWM control system is verified on the development board.The experimental results are the same as the simulation results. The results show that the double-mode overmodulation algorithm improves the shortcomings of the single-mode overmodulation algorithm and can output six PWM control signals with good performance,which achieves the expected design goal and verifies the correctness and feasibility of the design.