Control method for low-voltage static var generator based on voltage space vector

Abstract

The invention provides a control method for a low-voltage static var generator based on a voltage space vector, and belongs to the control methods for the low-voltage static var generators. The method comprises the steps that an actual output current and command current of a STATCOM are detected according to a STATCOM detection unit, an error current vector delta is determined, and a STATCOM mathematical model is combined to determine a constraint condition of an equivalent error voltage; the STATCOM adopts a double hysteresis control method, the width of an inner loop of a hysteresis loop is I<w1>, the width of outer outer loop of the hysteresis loop is I<w0>, when ||delta|| is grater than I<w0>, the error current vector delta is determined to be at the outer loop, and the current inner loop adopts an internal model controller to accurately calculate an output voltage u<c>* of the STATCOM; when the ||delta|| is greater than I<w1> and less than I<w0>, the error current vector delta is determined to be at the inner loop, a system is in a stable state, and a voltage vector method is adopted to control the STATCOM to output a fundamental voltage vector in a sampling period; when the ||delta|| is less than I<w1>, the error current is located in a dead zone, the on-off state remains unchanged, and the stability of the system is improved. A voltage space vector modulation method and the hysteresis control method are combined, the compensation precision is high, the response speed is fast, the switching frequency is low, and the performance requirements of the STATCOM are met.

Description

technical field [0001] The invention relates to a control method of a low-voltage static var generator, in particular to a low-voltage STATCOM control method based on a voltage space vector. Background technique [0002] There are a large number of inductive devices (such as transmission lines, transformers, etc.) in the distribution network, resulting in insufficient reactive power in the power system and voltage drop on the user side; with the rapid development and wide application of power electronic devices, there are a large number of inductive devices in the distribution network. Harmonic source, power quality problems such as voltage (current) distortion, three-phase voltage imbalance, voltage fluctuation and flicker appear in the power system, STATCOM device is a part of AC flexible transmission, not only can compensate the reactive power in the power system Power, and can also eliminate distorted current or voltage in the system in a compensating manner. Accurate c...

AI Technical Summary

Problems solved by technology

[0003] Theoretically, the output voltage of the low-voltage STATCOM can be accurately obtained by using a certain controller, and then modulated by the voltage space vector method to output the corresponding voltage, but the switching frequency of this algorithm is high, the response speed is slow, and the compensation effect is not ideal

Images