| In the recent 20 years, with the appearance of the new power electron apparatus and microprocessor and the development of the control theory on the Alternating Current (AC) motor, the technology of variable frequency speed variation has improved rapidly. A optimal design of the digital Pulse Width Modulation(PWM) motor speed variation system is proposed in this paper ,which uses Digital Signal Processor (DSP) TMS320Lf2407 special for digital motor control of TI corporation as the control center and uses Intelligent Power Module (IPM) PM25RSB120 of MITSUBISHI as apparatus of the inverter as well as the Space Vector Pulse Width Modulation(SVPWM) as the control algorithm.This thesis introduces the base theory and correlative information of variable frequency speed variation, and expatiates sinusoidal Pulse Width Modulation (SPWM). The principle of SVPWM is in-depth discussed, and a simple algorithm for SVPWM is ratiocinated.According to the parameter of the motor and the new requirement on AC motor control system, as for the hardware, the inverter module, protection module and control module based on the TMS320Lf2407 is designed. Several independent sources, optocouplers are used on the printed circuit board to void the interference. On the side of real time software, the module software is written by assembly language functions that interface with 16 bits fixed-point C code so that it can be amended and replanted easily. A novel D format is adopted to transform the unitary data to fixed-point data in the project. This D format can show the range of the data intuitively and express the real time data, which improves the speed and precision of SVPWM arithmetic greatly. The ratio of carrier wave is increased and the blend of current is reduced, as a result the performance of the system is ameliorated.This thesis project has finished the debugging of the AC motor control system, and the result shows that hardware and software of the designed system is in reason.
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