A wide frequency range adaptive repetitive control method for active power filters

Abstract

The invention discloses a wide frequency range self-adaptive repetitive control method of an active power filter. Firstly, the phase-locked loop is used to track the voltage frequency signal of the power grid in real time, and the switching frequency and the real-time power grid frequency are calculated under the premise that the switching frequency remains unchanged. Finally, the integer part of the ratio is taken as the number of beats of a fundamental wave lag of the improved repetitive controller, and the fractional part of the ratio is used to form the delay link, which is approximated by the first-order inertial link. In this way, in the case of grid frequency fluctuations, it can be ensured that the resonant frequency of repeated control is consistent with the actual fundamental and harmonic frequencies of the grid, so that the compensation effect of the active power filter will not be reduced when the grid frequency fluctuates.

Description

technical field [0001] The invention belongs to the technical field of active power filter current control, and more specifically relates to a wide frequency range self-adaptive repetitive control method of an active power filter. Background technique [0002] In the modern power system, the application of power electronic equipment is more and more extensive, such as metallurgy, chemical industry, mining and other departments use a large number of thyristor rectifier power supplies, and a large number of frequency converter speed control devices are used in industrial production. Various non-linear, impulsive, fluctuating and asymmetrical loads have increased substantially, resulting in increasingly serious power quality pollution such as three-phase current imbalance, voltage fluctuation, voltage drop and harmonics. At present, how to effectively improve power quality is a common concern of power supply departments, power users and power equipment manufacturers. [0003] ...

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Problems solved by technology

Another example is the Chinese invention patent "Adaptive Repetitive Control Method for Active Power Filters" (publication number: 102882211A) which discloses a power grid frequency adaptive method based on improved repetitive control, by dynamically adjusting the fundamental cycle of the repetitive inner membrane Lag the number of beats to achieve wide-range self-adaptation of grid frequency, but it does not consider the fractional part of the ratio between sampling frequency and actual grid frequency, resulting in the same decline in harmonic compensation performance

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