Distributed load current sensing system

Abstract

A distributed load current sensing system being connected to a power input terminal that is connected to a main power trunk that has one or multiple load branches connected thereto is disclosed to include a power bus connected to the main power trunk, an active power filter connected to the power bus and a load current sensor device coupled with each load branch for sensing the load current of each load branch and providing the sensed signal to the active power filter so that the active power filter can generate a compensation signal accurately.

Description

technical field [0001] The invention relates to an active power filter system, especially a distributed load current sensing system for compensating harmonic signals and reactive power of each load branch. Background technique [0002] Recently, with the advancement of science and technology, a large number of non-linear load devices have been used, such as frequency converters, lighting equipment, etc., to improve efficiency and convenience, but it also brings many power pollution problems, among which harmonic problems are the most Serious, and in order to improve the harmonic problem, power filters are generally installed to solve this problem. [0003] The power filter can be roughly divided into passive power filter and active power filter. The passive power filter is mainly composed of inductors and capacitors. It has the advantages of simple structure and low cost, but its disadvantages are its size and weight. Large, can only eliminate fixed harmonics, limited power...

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Problems solved by technology

[0003] The power filter can be roughly divided into passive power filter and active power filter. The passive power filter is mainly composed of inductors and capacitors. It has the advantages of simple structure and low cost, but its disadvantages are its size and weight. Large, can only eliminate fixed harmonics, limited power factor improvement, and easy to resonate with the power system; while the active power filter can effectively suppress all current harmonic components and improve the power factor on the power supply side, so Considering the needs of general systems, and in order to improve its reliability, large capacity and system scalability, most active power filters are used to operate in parallel with multiple small-capacity active power filters. The configuration method is as follows: figure 1 The system block diagram of the

[0004] The known active power filter technology applied in parallel operation can be mainly divided into several types, including parallel independent detection method, load current distribution method, multi-group compensation for different frequency current method, multi-group different switching frequency method and load information Transmission control methods and other methods, various active power filter control methods have their advantages and disadvantages, for example, such as figure 2 As shown in the system block diagram of , the load information transmission control method is to install active power filter devices on different load branches, and each active power filter will not only operate independently to compensate harmonic current and reactive power, but also can use the power network The road directly transmits information, connects and communicates with each active power filter, so that the active filters on different load branches can compensate each other and improve the system efficiency, but the disadvantage is that the distributed active power filter will cause maintenance and management problems. In addition to the inconvenience, the harmonic compensation function of the active power filter has the ability to attenuate the ability of the power network to transmit information; and the above-mentioned various active power filters have their own advantages and disadvantages, and more attention should be paid to their centralized The Existence Problem of Management and Decentralized Management

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