ACTIVE HARMONIC FILTER WITH AUTOMATIC ADJUSTMENT TO PERIODIC VARIABLE LOAD Russian patent published in 2021 - IPC H02J3/01 H02J3/18 

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering and electric power engineering and can be used in power supply systems of industrial enterprises or in a ship (drilling) power plant as a device for compensating harmonic distortions of three-phase network currents, both by higher harmonics and interharmonics. An active harmonic filter with automatic adjustment to a periodic variable load contains a series-connected passive filter for initial filtering out noise and high-frequency components, a three-phase uncontrolled bridge rectifier connected in parallel with the load, a capacitor for storing electrical energy and smoothing the rectified voltage, and a three-phase autonomous bridge inverter based on IGBT transistors with counter-parallel diodes and a control system connected to the network via an LC filter. The control system generates pulses based on the difference in real current received through a current transformer and the first harmonic extracted from it, decomposed into a Fourier series with the allocation of interharmonic current components and transmitted by PWM modulation to a three-phase autonomous bridge inverter, as the sum of several sinusoids with an interharmonic frequency. This will provide higher performance and increase the quality of noise suppression that occurs during periodic variable load.

EFFECT: implementation of the invention operating on a perturbation provides the accuracy of the active filter with less computational complexity than in active filters operating on the deviation of the current from the reference sinusoidal.

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