Design On PWM Variable Frequency Technology Of Ac Variable-speed System

The high-speed digital signal processing (DSP) can complete the complicated the algorithm of control, and suit for the velocity modulation system that create the high performance. In this paper, we studied the hardware and software design method of the speed control system base on the DSP which is produced by the TI company.The system is composed of the power circuit, protecting circuit, control circuit, sampling circuit. The power circuit includes rectification, filtering, inversion (IPM), drive of the IPM ;the protecting circuit includes the overvoltage and undervoltage protect, current limiting protect, wrong protection of IPM, overcurrent protect etc.The control circuit includes thesimplist system, the SCI,SPI circuit, the debug input circuit,PWM pulse produced circuit,the A/D ,D/A circuit.The sampling circuit incluedes the current sampling ,voltage sampling and the speed sampling circuit.On software part, thought that SVPWM is better then SPWM on the high voltage using rate, and it is more fit to be used on the numeral control system. In this paper we give out a motor control programme base on the theory of open-loop SVPWM.At last, the experiment result proves the control system can be used from 0 to 50 Hz, and it has strong load performance when the frequency is above 10 Hz.