Cascade-structure-based hybrid active power filter

Abstract

The invention discloses a cascade-structure-based hybrid active power filter, which belongs to the technical field of harmonic compensation devices of medium voltage distribution networks. The active power filter consists of a single-tuned passive filter, a three-phase H-bridge cascade multi-level inverter and a control system, wherein the three-phase H-bridge cascade multi-level inverter consists of three bridge arms which are in Y-shaped or delta-shaped connection; each of the bridge arms consists of 1 to N H-bridge inversion units which are connected in series directly; four insulated gate bipolar translators (IGBT) with anti-parallel diodes are connected with a direct current capacitor Cdc in parallel after being connected via a H bridge to compose a H-bridge inversion unit; the direct current capacitor Cdc is the voltage source of the H-bridge inversion units; the single-tuned passive filter consists of a reactor and a capacitor which are connected in series; and the control system consists of a harmonic current detection module, a harmonic current control module, a pulse width modulation (PWM) signal generation module and a direct-current side voltage control module. The cascade-structure-based mixed active power filter of the invention has the advantages of simple structure, small product volume, high reliability, low requirements on switch devices and low cost.

Description

technical field [0001] The invention belongs to the technical field of harmonic compensation devices for medium-voltage distribution networks, and in particular relates to a hybrid active power filter based on a cascade structure. Background technique [0002] With the development of power electronics technology, high-power power electronic devices such as frequency conversion speed control devices, AC and DC electric arc furnace equipment, high-power electrolysis devices, and traction equipment for electrified railway locomotives have been widely used. While these devices greatly improve production efficiency, they also bring great harmonic pollution to the power system, causing overload, overheating, increased loss of electrical equipment, capacitor overvoltage, and protection malfunctions. Governance needs are constantly increasing. [0003] At present, a large number of passive filters have the disadvantages that the harmonic compensation characteristics are affected by...

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Problems solved by technology

However, this method still has the problem of high voltage withstand of power electronic devices when applied to higher voltage levels (such as my country's medium voltage 10kV system). Although this problem can be solved by increasing the number of levels, it will make the inverter The structure is complex, and there are problems such as reduced reliability of the inverter (damage to any component will affect the normal operation of the device) and complicated voltage equalization control on the DC side.

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