Control method of wide frequency range multi-type harmonic comprehensive governance system

Abstract

The invention discloses a control method of a wide frequency range multi-type harmonic comprehensive governance system. The control method of the wide frequency range multi-type harmonic comprehensive governance system comprises the wide frequency range multi-type harmonic comprehensive governance system. The wide frequency range multi-type harmonic comprehensive governance system comprises a series active power filter and a parallel passive power filter. The series active power filter comprises an inverter, a filter circuit, and a series transformer. The inverter is connected with a secondary side of the series transformer through the filter circuit. A primary side of the transformer is in series connection with grid lines. The parallel passive power filter is in parallel connection with a load side of the series active power filter. The control method of the wide frequency range multi-type harmonic comprehensive governance system is based on a control method of a fundamental wave magnetic flux compensation principle of the transformer. A fundamental wave compensating current is injected at the secondary side of the transformer. The size of the fundamental wave compensating current is k times larger or smaller than a power system current, and the direction of the fundamental wave compensating current is opposite to that of the power system current. Impedance of the series transformer to a fundamental wave is zero. Normal operation of the power system cannot be influenced. High impedance to the harmonic wave is presented. Filtering effect of a passive power filter can be improved. A harmonic voltage is compensated. Simultaneously, resonance of power harmonic in series or parallel connection can be well restrained.

Description

technical field [0001] The invention relates to an active power filter, in particular to a control method for a multi-type harmonic comprehensive control system in a wide frequency domain. Background technique [0002] With the increasing application of power electronic devices, the types of harmonic sources are increasing, and the harmonic environment of power grids is becoming more and more complex. Power grid rectifier is a typical harmonic source, which can be roughly divided into current type harmonic source and voltage type harmonic source according to the difference of its DC side filter components. The rectifier device with inductance filter on the DC side can be regarded as a current-type harmonic source, and the rectifier device with capacitor filter on the DC side can be regarded as a voltage-type harmonic source. Due to the widespread application of early current-type rectifiers, there are many researches on the control methods of current-type harmonic sources a...

AI Technical Summary

Problems solved by technology

Some research conclusions show that the parallel active power filter is suitable for compensating the current harmonic source, and the series active power filter is suitable for compensating the voltage harmonic source, but the parallel active power filter is used to compensate the voltage harmonic source. When the series active power filter is used to compensate the current-type harmonic source, it will cause harmonic amplification, and the compensation effect is not good.

The traditional series hybrid active power filter can compensate the current-type harmonic source, but the passive part generally uses multiple sets of single series resonant passive power filters. When the load side contains harmonic voltage, it is easy to cause the The harmonic current of the source power filter is too large, so it is not suitable for occasions where there is harmonic voltage distortion on the load side

The hybrid passive filter composed of series passive filter and parallel passive filter can realize comprehensive compensation for voltage-type and current-type harmonics, but the change of series resonant passive filter parameters and grid frequency deviation cause The partial harmonic of the filter and the influence of the internal resistance of the filter may cause a large fundamental wave voltage drop, affecting the normal operation of the power grid

The traditional series active power filter uses control methods such as detection of load voltage, detection of power supply current, compound detection, etc. Because it directly controls the harmonic signals of different frequencies in a unified manner, it is easy to generate amplitude and phase errors in steady state, and this kind of The error is not easy to adjust and correct, and the accuracy of steady-state control is not high enough

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