Research Of Dual-PWM Inverter And Its Control Strategy

With the rapid development of power electronic technology and controltechnology, the ac motor variable frequency speed regulation technology is widelyused.The harmonic pollution problem is brought by traditional inverter which adoptsuncontrolled or phase controlled rectifier.Dual-PWM inverter which based on PWMtechnology has aroused widespread concern. This kind of device has many advantages,including nets side current is sine wave、the power factor is approaching to1、realizebi-directional flow of energy. Of particular importance is that it can actively eliminatethe harmonic pollution problem, improve the inverter performance of speedadjustment.The basic structure，operation principle and mathematical model of PWM rectifierare studied in this paper. The parameters of PI regulator of voltage loop and current loopare designed. By the method of voltage oriented control, the AC-side current can betransformation into DC current.This can make the system get a good dynamic and staticperformance and simplify the control requirements. The PWM inverter uses the rotorfield-oriented vector control scheme to realize the electrical machinery velocitymodulation and the torque control.According to the shortage of the independent control, an integration controlstrategy for dual-PWM inverter is proposed.Detailed research of load currentfeedforward control is also presented. Through the simulation results prove the controlstrategy can effectively restrain the dc bus voltage fluctuation, improve the systemreliability and anti-interference ability, reduce the demand for capacitance capacity andcut down the system volume and cost.Matlab7.0/Simulink is used, and the simulation results verify the suggestedscheme.Based on the above study, experimental device of dual-PWM variablefrequency system has been designed, including TMS320F2407A as main apparatus.Experimental results are taken by experimental study.