LCL-type active power filter and control method thereof

Abstract

The invention provides an LCL-type active power filter and a control method thereof. The LCL-type active power filter comprises a converter T1 and a control system, wherein one side of the converter T1 is connected in parallel with a DC capacitor C, an LCL filter circuit is arranged at the other side of the converter T1 and comprises a filter capacitor Cf, a converter T1 side is connected with a filter inductor L1, a power grid side is connected with a filter inductor L2, the control system is connected with an output end of the single-phase converter T1, the filter capacitor Cf, the DC capacitor C and a load respectively by a filter inductor L1 current sampling circuit, a filter capacitor voltage sampling circuit, a DC capacitor voltage sampling circuit and a load current sampling circuit, and the control system is used for closed-ring control on a current of the inductor L1 at the converter T1 side. According to the control method of the LCL-type active power filter, a filtering effect of the LCL-type active power filter can be improved by introducing virtual impedance control and phase compensation control.

Description

[0001] 【Technical field】 [0002] The invention relates to the technical field of active filters, in particular to an LCL type active power filter and a control method thereof. [0003] 【Background technique】 [0004] The active filter uses the output current of the converter to compensate the load harmonic current to realize the filtering function. This requires the output current of the active filter to meet two conditions, one is that the amplitude is equal to the amplitude of the compensated harmonic current; the other is that the phase is opposite to the phase of the compensated harmonic current. Therefore, it has high requirements for current control. [0005] Compared with the traditional L-type active filter, the LCL-type active filter can take into account the low-frequency gain and high-frequency attenuation, which is the development direction of the active filter, but the high-order characteristics of the LCL filter make it resonant The problem. It affects its con...

AI Technical Summary

Problems solved by technology

[0005] Compared with the traditional L-type active filter, the LCL-type active filter can take into account the low-frequency gain and high-frequency attenuation, which is the development direction of the active filter, but the high-order characteristics of the LCL filter make it resonant The problem

It affects its control of the output current, making it difficult to keep consistent with the command value in amplitude and phase

[0006] At present, the output filter network of active power filter is gradually LCL network, because compared with the L-type network, LCL can take into account the low-frequency gain and high-frequency attenuation, but the inherent resonance characteristics of the LCL network make the control more complicated

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