Model prediction direct power control method based on three vectors

Abstract

The invention discloses a model prediction direct power control method based on three vectors, and the method comprises the steps: analyzing the impact on active and reactive power change rates from anon-zero voltage vector and a zero voltage vector, predicting the amplitudes of the active and reactive power under different combinations of voltage vectors, selecting a proper combination of voltage vectors according to a minimum power error rule, and calculating the corresponding action time; driving six switching tubes to operate through the pulse-width modulation technology, controlling theactive and reactive power, and following the given values. The method does not need an AC side grid voltage sensor, thereby saving the cost and improving the reliability of a system. In one period, the method employs three voltage vectors, so the method can effectively inhibit the power pulsation. The method achieves the compensation for the active and reactive power, and reduces the distortion rate of current harmonic waves. The method can avoid the static errors of the active and reactive power through prediction power control.

Description

technical field [0001] The invention relates to electric transmission technology, in particular to a three-vector-based model prediction direct power control method. Background technique [0002] At present, with the development of power electronics technology and the continuous improvement of the performance of semiconductor switching devices, the three-phase PWM rectifier has developed from uncontrolled rectification to controlled rectification. The PWM rectifier uses fully controlled devices instead of diodes or thyristors, the power factor is adjustable, and energy can flow in both directions, realizing the real "green power conversion". Since the grid side of the PWM rectifier has the characteristics of a controlled source, it can also be used in active power filters, static var generators, unified power flow controllers, superconducting energy storage and other fields, and has great research value. [0003] For the control of the three-phase PWM rectifier, domestic an...

AI Technical Summary

Problems solved by technology

Direct power control adopts the control structure of the voltage outer loop and the power inner loop, and selects the appropriate switch table through the hysteresis comparison of active and reactive power and the position of the grid voltage vector, and then controls the action of the PWM rectifier, so that the active power and reactive power The power follows the given value, but the switching frequency is not fixed, the design of the output filter is more complicated, and only under the condition of a higher sampling frequency can a better control effect be achieved

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