Research On Converter Of Dual-PWM Technology

With the development of power electronics, modern control theory, computer technology, AC driving system has been the primary direction of electric driving system because its high speed, large capacity, favorable driving system. A novel dual-PWM converter is introduced with the foundation of pulse width modulation which realizes bidirectional fluxion of energy and enhances power factor of system. The three-phase dual-PWM variable-frequency system can be divided into the PWM inversion and PWM rectifier two parts in this paper. The control system can not only realize bidirectional flow of energy but also run at unity power factor, thus the harmonic pollution on the grid can be effectively reduced.In this article the three-phase PWM rectifier structure and its control method is analyzed deeply based on the introduction of the dual-PWM variable-frequency system topology. The three-phase VSR mathematical model based on switching function is provided in the three-phase static coordinate and two-phase rotating coordinate. The operation principle of the three-phase VSR is studied. According to the systems control goal, the voltage and electric current double closed-loop control structure is used to carry on the control to VSR. The PWM inverter uses the rotor field-oriented vector control scheme to realize the torque control and the electrical machinery velocity modulation. The SVPWM control technology is used both in the rectifier side and inverter side of dual-PWM. because of the similar structure of the two sides, the inverter side is used as an example to analyze control method of SVPWM and the theory.Using Power Electric toolbox offered by MATLAB to finish the simulation experiment under Simulink environment and to verify systematic exactness and feasibility. The experiment results show that the dual-PWM converter could effectively restrain the harmonic pollution with sinusoidal input currents, perform at high power factor and improve the power quality. The experimental results also met the design requirement.