Active power filter and limiting method for peak current of active power filter

Abstract

The invention discloses an active power filter and a limiting method for peak current of the active power filter. The active power filter includes a power unit, a current transformer, a Hall sensor, a controller, and a peak limiting circuit; the controller is connected to the current transformer and the Hall sensor, and is used for calculating harmonic current to be compensated according to nonlinear load current, limiting a preset peak of the harmonic current to be compensated, then performing closed-loop regulation on the harmonic current to be compensated according to feedback current of the Hall sensor, and finally generating a corresponding PWM driving signal according to the harmonic current to be compensated; the PWM driving signal is transmitted to the power unit via the peak limiting circuit to drive the power unit to generate corresponding output current; the peak limiting circuit limits the pulse width of the passing PWM driving signal according to the feedback current of the Hall sensor. According to the invention, when the peak overshoots, the active power filter achieves not-stop protection, does not damage devices, and compensates the harmonic current to the utmost extent.

Description

technical field [0001] The invention relates to the technical field of active power filters, in particular to an active power filter and a peak current limiting method thereof. Background technique [0002] The active filter is mainly used to compensate the harmonic current of the system. When the harmonic current capacity of the system is large and the capacity of the active filter is insufficient, the compensation capacity will reach the maximum capacity of the active filter. The proportion of high-order harmonics in the current system is also relatively large, resulting in the final capacity to be compensated not only the effective capacity but also the instantaneous capacity, especially the instantaneous current peak can easily cause the system to exceed the capacity and self-protect. [0003] At present, most self-protection methods are to perform peak overcurrent shutdown protection on the output current of the power output unit of the active power filter, so as to avo...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art, aiming to solve the problem that the harmonic current of the system cannot be compensated normally when the output current of the power output unit of the active power filter is protected by peak overcurrent shutdown Problems that cause greater losses to users

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