Integral power quality regulator and control method

Abstract

The invention discloses an integral power quality regulator. The integral power quality regulator comprises series-connection and parallel-connection active power filter units, a measuring unit and a control unit, wherein the parallel-connection active power filter unit and a parallel-connection passive filter unit are serially connected to each other to form a parallel-connection unit and are connected to a system in parallel; the series-connection active power filter unit is controlled by a series-connection control unit, and outputs sine-wave current by driving switch tubes of a first inverter unit; the parallel-connection active filter unit is controlled by a parallel-connection control unit and outputs appointed voltage by driving various switch tubes of a second inverter; and the parallel-connection passive filter unit is an LC (liquid chromatography) filter circuit, and is used for providing low-impedance access for load harmonic current and compensating reactive power of a load. By the integral power quality regulator, the shortcoming that the original parallel-connection active filter is high in capacity and high in manufacturing cost is overcome; a detection and control system is simple; an output tracking effect is high; a compensation effect is high; cost performance is also high; and hardware implementation is facilitated.

Description

technical field [0001] The invention belongs to the field of electric power system automation, and in particular relates to a power quality regulator. Background technique [0002] In recent years, with the development of power electronics technology, nonlinear, unbalanced and impact loads such as rectifiers, frequency conversion speed control devices, electric arc furnaces, and electrified railways in distribution networks have continued to increase. While these loads have greatly improved production efficiency, they have also brought power quality pollution problems to the grid, such as harmonics, low power factor, unbalance, and voltage fluctuations and flicker. The integrated power quality conditioner (Unified Power Quality Conditioner, UPQC, also known as unified power quality controller) can comprehensively compensate these power quality problems. sensitive load. To sum up, the comprehensive power quality conditioner currently being applied and researched has the fol...

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Problems solved by technology

[0006] The above-mentioned integrated power quality conditioner has the following problems: ①The parallel active filter withstands a relatively large voltage (equal to the entire load voltage), so the required capacity is relatively large, and it has great technical difficulty, high cost and high equipment operation efficiency in project implementation low level problem

②The series active filter is controlled as a controllable voltage source, and its output reference voltage usually contains certain harmonics, which makes the detection and control system complex and the output tracking effect is not good

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