The Design of SVPWM Waveform Generator Based on CPLD_DSP

Abstract

Space vector pulse width modulation (SVPWM) control technology could obtain quasi circular rotating magnetic field by switching the space voltage vector of the inverter. Under the condition of low switching frequency, the performance of AC motor was better than that of sine wave pulse width modulation. When this technology was applied to inverter control system, better output voltage waveform could be obtained than conventional six step waveform. And in order to further improve the control performance of the motor, it was very necessary to design SVPWM waveform generator. The design of SVPWM waveform generator based on Complex Programmable Logic Device and Digital Signal Processing (CPLD_DSP) was introduced in the article. The main idea of SVPWM was to synthesize reference voltage vector by switching space voltage vector of inverter. Time holding data and sector number could be calculated from coordinate switch of Voltage gathered from inverter by DSP. And the data was sent into CPLD. SVPWM waveform was generated by state machine programed in VHDL. Finally program was download in CPLD chip named EPM1270T144C5N. The transformation from time signal to SVPWM switch signal was finished successfully. The three phrase output signal had good coherence. Thus the controlling function of the motor control system was improved in a certain extent.