Frequency wide-range self-adaptive repetition control method of active power filter

Abstract

The invention discloses a frequency wide-range self-adaptive repetition control method of an active power filter. First of all, voltage frequency signals of a power network are tracked in real time through a phase-locked loop, under the condition that a switch frequency is unchanged, the ratio of the switch frequency to a real-time power network frequency is calculated, finally, the integer portion of the ratio is taken as a number of beats of a fundamental wave lag of an improved repetition controller, and the decimal portion of the ratio forms a time-delay link which is approximated by use of a one-order inertia link, such that under the condition that the power network frequency fluctuates, it is ensured that the resonance frequency of the repetition controller is consistent with the actual fundamental wave and harmonic frequency of the power network, and thus the compensation effect of the active power filter in case of fluctuations of the power network frequency is not reduced.

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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