Three-phase high-voltage cascading mixing power compensator and control method thereof

Abstract

The invention discloses a three-phase high-voltage cascading mixing power compensator and a control method thereof. In order to compensate higher harmonic current, a single-phase active filter is connected on an input filter inductance of the three-phase high-voltage cascading mixing power compensator in parallel, since majority of basic wave voltages are born by a cascading multi-electrical-level PWM (pulse-width modulation) current transformer, the basic wave on the filter inductance is extremely small, a low-voltage high-frequency switch appliance can be adopted for the active filter to realize the compensation of high harmonic current; and meanwhile an LC (logic controller) single-tuning filter is connected onto the cascading multi-electrical-level PWM current transformer in parallel, a low-impedance passageway is provided for high harmonic current, and the harmonic compensation capability of the active filter is improved. According to the compensator and the control method thereof, comprehensive compensation on reactive power and harmonics can be realized, and the electrical energy quality of a high-voltage power distribution network is greatly improved.

Description

Technical field [0001] The invention relates to a three-phase cascade type converter, in particular to a high-power three-phase high-voltage cascade type power hybrid compensator and a control method thereof. Background technique [0002] With the expansion of the scale of industrialization and the rapid development of science and technology, on the one hand, the electrification of various sectors of the national economy is increasing day by day, and a variety of complex, sophisticated, and new high-tech user equipment that is sensitive to changes in power characteristics continues to increase. The requirements for power quality are getting higher and higher; on the other hand, rapid impact loads (such as electric arc furnaces, rolling mills, drawworks, etc.) and large-capacity power electronic nonlinear loads in the distribution network have increased dramatically, causing voltage fluctuations and flashovers in the power grid. Changes, unbalanced three-phase power supply and dis...

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Problems solved by technology

[0004] However, due to the limitations of power electronic devices, this structure uses high-power switching devices, and its switching frequency is low (the switching frequency of 3.3kV power switching tubes is generally lower than 2kHz, and the switching frequency of 4-6kV power switching tubes Generally lower than 1kHz), it can only compensate the fundamental reactive current, and cannot effectively compensate the high-order harmonic current

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