Active power filter and control method and device thereof

Abstract

The invention belongs to the technical field of active power filters, and particularly relates to an active power filter and a control method and device thereof. The active power filter comprises a three-phase inverter, a three-phase rectifier and a three-phase power supply, wherein the alternating current side of the three-phase inverter is used for being connected with a power grid where the nonlinear load is located, and the direct current side of the three-phase inverter is connected with the direct current side of the three-phase rectifier; and the alternating current side of the three-phase rectifier is connected with the three-phase power supply. The active power filter can control the three-phase inverter to generate a harmonic suppression current which is equal to the harmonic current component in size and opposite to the harmonic current component in direction, injects the harmonic suppression current into a power grid, achieves the purpose of harmonic suppression, has the characteristics of high controllability and quick response, is not influenced by a system, and does not have the threat of harmonic amplification. The reliability of safe operation of the power grid and the transformer is improved, and great practical significance is achieved for the whole power system.

Description

technical field [0001] The invention belongs to the technical field of active power filters, and in particular relates to an active power filter and its control method and device. Background technique [0002] In recent years, rectification devices, frequency conversion speed control devices, industrial power supplies and various power electronic devices in the distribution network have been added continuously, resulting in nonlinear loads and imbalances that distort the voltage and current of the power system, seriously affect the quality of power supply. Therefore, solving the harmonic and reactive power problems in the power system and improving the power supply quality of the power grid have become more and more problems that cannot be ignored. [0003] Due to the development of power electronics, higher requirements are placed on the quality of power supply. Traditional harmonic suppression and reactive power compensation mainly use LC filters, which are widely used i...

AI Technical Summary

Problems solved by technology

Afterwards, many large well-known electrical companies in the world have launched their own similar series of products, such as Thyristor Controlled Reactor (TCR), that is, two anti-parallel thyristors are connected in series and a reactor is connected in parallel to the power grid. Change the reactive power absorbed by the compensator; thyristor switched capacitor (Thyristor Switched Capacitor—TSC), through two anti-parallel thyristors connected to or disconnected from the grid through the capacitor, the thyristor replaces the conventional mechanical switch to solve the frequent switching of capacitors The small inductance in series is to suppress the inrush current generated when it is put into the power grid, and the number of capacitor groups to be put in is determined according to the size of the reactive current, but it can only be a step-by-step adjustment of the reactive current; the thyristor-controlled reactor and the fixed capacitor ( Fixed Capactior—FC), etc., and hybrid devices based on the above types (such as TCR+TSC, TCR+FC, etc.)

Images