The Research On The Control System Of Multilevel Inverter For Asynchronous Motor Based On DSP

Multilevel inverter technology is a pop research in high voltage and high-power converting fields. It can synthesize multilevel output with the distribution of DC voltage and the combination of different switching actions to reduce voltage stress across the switches and bulk of the equipment,and lessen output harmonic distortion and switching loss of the inverter. This paper mainly investigates the Space Vector Pulse Width Modulation (SVPWM) technology and the Vector Control technology of variable speed system of diode Neutral-Point-Clamp (NPC) three-level Voltage Source Inverter (VSI) for induction machine.At first,the status quo of multilevel technique is summarized,and four basic topologies of multilevel and several control strategies are analyzed in detail and compared in this paper;then the principle of the three-level SVPWM is specified, the cause of unbalance of the neutral-point voltage is detailedly analyzed and ,consequently, a real-time control method is presented to control the neutral-point potential fluctuation;the basic rule of vector control of induction machine is summarized,and for current model ,a corresponding numerical expression is gained by the discretization of time domain on the basis of continuous time expression; a simulation platform of three-level inverter control system is established,thus,an effective tool is provided for the research of the three-level inverter control system;at last, considering the control requirement of three-level inverter and the heavy operation quantity of SVPWM algorithm, the TMS320LF2407DSP is chosen as the signal-processing chip, and the designs of basic hardware circuits and software are also presented.