Research On The Implementation Of Reversible Ac-dc-ac Variablefrequency Adjustablespeed System Based On Dsp

?With rapid development of power electronics technology, computer science technology, automatic control technology, AC variable-frequency technology has been developing rapidly. Because of significant energy benefit, high speed-adjust precision, wide speed-adjust scope and perfect protection function, it wins the customers'recognition.However,it contains harmonic currents in supply-side ,which will impact power quality negatively. Meanwhile the inverter's output voltage also contains upper harmonics, which will cause torque pulsation and noise to motors and may even cause damage to motors. the dual PWM converter is composed of common converter and PWM rectifier ,it can improve the utilize percentage of power by feeding back the regenerated energy by motor machine to power grid ,and also can boost the power factor,reduce the harmonic pollution,improve the speed-adjust performance of the converter for the stable DC output voltage.Firstly the basic topology, operation principle, mathematical model of PWM rectifier and inverter are analyzed, the optimum control method that is easy for digitizing is chosen. Then asynchronous machine and the relation of active power and reactive power based on its mathematical model and equivalent circuit are analyzed and researched, and a novel combined control strategy for dual PWM converter based on the analysis of traditional combined control strategy is induced, the utilization of SVPWM technique in variable-frequency AC motor control system is also researched . Then the dual PWM variable frequency system is designed , Including the signal detect, process, system protection and control circuits of asynchronous machine based on main processor DSP TMS320F2812,IPM(Intelligent Power Module)driving circuit, protection circuit ,signal process circuit and power circuit .and all circuits are simulated by Orcad/PSpice and Matlab to verify the control strategy. Finally the experiments are implemented and the experimental results are gotten. The research production of this paper will offer practical value to research and develop dual PWM variable frequency system further.