Sliding mode proportional-resonant control method based on three-phase Vienna rectifier

Abstract

The invention relates to a sliding mode proportional-resonant control method based on a three-phase Vienna rectifier. The method comprises the steps that a three-phase rectifier circuit equation is derived according to a Kirchhoff's law and a topological structure of the three-phase Vienna rectifier; the voltages Uc1 and Uc2 of an upper capacitor and a lower capacitor on the direct current side, the currents ia, ib and ic on the alternating current side and the voltage Ua, Ub and Uc are collected corresponding, the collected voltages Uc1 and Uc2 of the upper capacitor and the lower capacitor on the direct current side are summed to obtain the total voltage Udc, the difference value of the Udc and the voltage reference value Udcref on the direct-current side is subjected to treatment through a sliding mode controller so as to obtain a current reference value idref, the current reference value idref is substituted into iqref = 0, then 2s / 2r conversion is carried out so as to obtain i alpha and i beta, the alternating-current side currents are subjected to 3s / 2r conversion so as to obtain the current actual values ialpharef and ibetaref, then the difference between the ialpharef and the ialpha and the difference between the ibetaref and the ibeta are obtained, then proportional resonance control is carried out so as to obtain usalpha and usbeta, and the angle theta of a phase-locked loop is obtained through the voltage Ua, Ub and Uc; and the usalpha, the usbeta and the voltage udc on the direct-current side, the current ia, ib and ic on the alternating-current side and a mid-point voltage signal are led into the controller together, and finally a switch-on-off signal of the Vienna rectifier is obtained. According to the method, the robustness and the dynamic performance ofthe Vienna rectifier are improved, the reaction speed of the Vienna rectifier is increased, the voltage fluctuation on the direct-current side is reduced, and meanwhile, better anti-load-disturbanceresistance is achieved.

Description

technical field [0001] The invention belongs to the field of Vienna rectifiers, in particular to a sliding mode proportional resonance control method based on a three-phase Vienna rectifier. Background technique [0002] The Vienna rectifier is an excellent three-level rectifier. Compared with the traditional three-level PWM rectifier, it has the advantages of saving the number of switching devices, and the withstand voltage of the switching devices is half of the output voltage, which reduces the device stress and does not need to set the driving dead time. Control algorithm Relatively simple and other advantages make it a hot research direction of rectifiers today, and Vienna rectifiers can better control harmonic pollution of power grids, improve power quality, reduce harmonic content in power grids, and improve power factor. In practical applications, the double closed-loop of Vienna rectifier generally adopts PI control strategy, but PI control is difficult to achieve n...

AI Technical Summary

Problems solved by technology

Although this strategy can make the adjustment of current relatively simple, the system needs to increase the complexity of PI regulator parameter setting and control system design

And for the Vienna rectifier, the conventional dual PI control is used, the system dynamics are relatively poor, and the contradiction between the voltage overshoot and the speed and accuracy is also prominent, and it is difficult to achieve the ideal control effect

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