Active tuning type hybrid filter and control method of active tuning

Abstract

The invention discloses an active tuning type hybrid filter, which is characterized in that the output of an APF (active power filter) is directly connected with two ends of a filter reactor L of a PPF (passive power filter) in parallel (or by a coupling transformer in parallel). The invention also discloses a control method of active tuning, which comprises the following steps by using the hybrid filter: connecting a branch with a linear load required to filter in parallel; obtaining each single harmonic current component to be filtered by detecting a harmonic current; comparing a condenser voltage with a reactor voltage and then carrying out PI adjustment so as to obtain the detuning degree under the condition of the frequency of harmonic to be filtered; generating the detuning degree into a harmonic compensating current weighting coefficient; forming a harmonic compensating current command; generating an active current command of fundamental waves; summing to obtain a command current of the APF; and generating a PWM (pulse-width modulation) drive signal after the command current and an actually-output current signal are subjected to PWM generation and drive. The method is remarkable, safe and reliable.

Description

technical field [0001] The invention belongs to the technical field of power filtering, and relates to an active tuning hybrid filter, and also relates to a control method for performing active tuning on the active tuning hybrid filter. Background technique [0002] With the wide application of large-capacity power electronic devices and various electronic equipment, the harmonic pollution of the grid is becoming more and more serious, which not only threatens the safe operation of the power system and electrical equipment, but also significantly increases the power loss of the grid. Harmonic control equipment can be divided into passive power filter (hereinafter referred to as passive filter or PPF), active power filter (hereinafter referred to as active filter or APF), and a hybrid power filter formed by the organic combination of the two filter (hereinafter referred to as hybrid filter or HPF). [0003] Passive filters or active filters used alone have their own problems...

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Problems solved by technology

[0005] The purpose of the present invention is to provide an active tuning hybrid filter, which solves the need to detect the load current or power supply current as a feedback signal in the prior art, and is not suitable for applications with distributed power sources or distributed nonlinear loads The control of harmonics in the power distribution system; the capacity of the active filter part is relatively large; the three-phase unified control, its performance is easily affected by the imbalance of three-phase LC parameters; the problem of harmonic current limiting protection of passive filters is not considered

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