| Based on large-capacity semiconductor devices, the combation of high-performance control strategies and multi-level topology structure to develop the high-voltage high-power drive systems is significance of China's industrial control and energy saving. In this thesis, the cascaded seven-level inverters and its space voltage vector pulse width modulation (SVPWM) technique is discussed, which is proved the feasibility by simulation and experiments.First of all, the development prospect of multilevel inverter is reviewed. The topology and modulation method of high-power inverter is introduced. Described the implementation principle of multi-level inverter with cascaded H bridge based on 2-level control technique. Then introduced the cascaded multi-level control method based on common two-level SVPWM, the cascaded multi-level control method based on random zero-vector position SVPWM and the cascaded multi-level control method based on the unified control SVPWM method.In order to improving the performance and reliability of system, the original inverter control circuit is improved based on digital signal processor (DSP) and field programmable gate array (FPGA), and the control procedures is improved. In control program, DSP is mainly responsible for generating the initial control signal. FPGA is mainly responsible for generating 36 and control signals, and generating the dead band. DSP generate 3 way control signals based on control algorithm, FPGA receive the data form DSP and generate 36 way control signals according to the simplify modulation theory.Finally built the simulation model based on the principles of three cascaded H bridge SVPWM control methods. Set the simulation parameters with the actual Experimental platform parameter, and analyzed the simulation result. Summarized one simple and practical cascaded multi-level control method based on SVPWM. Use experimental platform for test verification. The frequency control function of inverter is Successful implemented. |
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