Three-vector-based low-complexity model forecasting direct power control method

Abstract

The invention discloses a three-vector-based low-complexity model forecasting direct power control method. The method comprises the following steps: by taking negative conjugate complex power under asynchronous rotating coordinate system as a control variable, calculating a sector where an optimal non-zero voltage vector is positioned according to a power forecasting model of a system so as to select a corresponding voltage vector combination; then calculating action time of each voltage vector by adopting the principle of a minimum error between active power and reactive power; and driving six switching tubes to operate through a pulse width modulation technology, so as to control the active power and the reactive power to follow set values. The method saves the cost and improves the reliability of the system; the control algorithm can be simplified; the power pulse can be effectively suppressed; a switching frequency is fixed, so that the design of a filter is facilitated; the active power and the reactive power are compensated to reduce the current harmonic distortion rate; and by adoption of forecasting power control, no offset is caused between the active power and the reactive power.

Description

technical field [0001] The invention relates to electric transmission technology, in particular to a three-vector-based low-complexity 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 rectifi...

AI Technical Summary

Problems solved by technology

However, because the traditional model predictive control needs to calculate the predicted value of active power and reactive power six times, the calculation is more complicated, and the performance requirements of the digital signal processor are relatively high; and two voltage vectors are used in one cycle, and the switching frequency is not fixed.

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