Study And Design Of Dual-PWM Variable Frequency Speed Regulation System Based On DSP

With the advantages of simple structure and easy control, the traditional inverter iswidely used in different fields. However, harmonic pollution and energy waste whichcaused by diode’s uncontrollable rectifier have become a serious problem increasingly.Dual-PWM variable frequency speed regulation system based on AC-DC-AC configurationis put forward in this paper. The system use PWM rectifier instead of diode rectifier，overcome the lack of the traditional inverter, it can sinusoidal input currents, perform athigh power factor and make the power transmit bidirectionally, especially suitable toapplication fields where motor to run positive and negative frequently, such as pumping unitand electrical elevator, etc.Dual-PWM variable frequency speed regulation system includes PWM rectifier andPWM inverter. Dynamic model is very important for further study. So the PWM rectifierand PMSM’s dynamic model were constructed at first. Then, based on the vector controlprinciple, dual closed-loop control system which composed of outer voltage loop and innercurrent loop was designed for PWM rectifier in the two-phase synchronous rotatingcoordination. I_d=0rotor field orientation vector control strategy was designed for PMSMinverter. On these basis, the simulation model of dual-PWM converter was created bymeans of Matlab software to verify the feasibility of this control strategy.Finally, the experimental platform of Dual-PWM variable frequency speed regulationsystem which took DSP+CPLD as its center control chip was constructed. Analysed themain hardware and software modules.There are three experiments done in this paper,including PWM rectifier driving resistive load, elevator transformation experiment, anddual-PWM converter driving PMSM. The experiment results show that the dual-PWMconverter could effectively restrain the harmonic pollution with sinusoidal input currents,perform at high power factor and improve the power quality.