Active harmonic wave suppressing device and control method

Abstract

The present invention is active harmonic suppression device and its control method. The device includes one serial LC combination comprising one energy accumulating capacitor, one electric energy converter, one filtering inductor and one virtual power compensating capacitor; one filtering CR combination and one control circuit. The energy accumulating capacitor provides one first voltage; the electric energy converter connected electrically to the energy accumulating capacitor switches the first voltage to output and provide one compensating voltage; and the serial LC combination and the filtering CR combination convert the compensating voltage into one compensating current injected to power line to eliminate the harmonic current the load produces and to make the power supply current possess sinusoidal waveform. The control method of the device includes calculating expected output voltage, pulse width regulation to produce switching signal and injecting compensating current.

Description

technical field [0001] The invention relates to the technical field of harmonic filtering in electric power supply, in particular to an active harmonic suppressing device and a control method which are applied in parallel connection with a nonlinear load to filter the generated harmonic current. Background technique [0002] In recent years, due to the rapid development of semiconductor technology, many power electronic components with good controllability, high voltage and high current resistance have been developed. These components have been widely used in power equipment, such as motor drives, electric arc furnaces, trams, Chargers and lighting fixtures, etc. Due to the non-linear input characteristics of these devices, they will generate a large number of harmonic currents. The existence of harmonic currents will cause some problems, such as overheating of transformers, disturbance of rotating machinery, distortion of supply voltage, damage of power components and func...

AI Technical Summary

Problems solved by technology

Although the traditional active power filter can achieve the purpose of harmonic filtering, it still has several disadvantages: (1) It is necessary to use a filter inductor with a large inductance value to filter out the harmonics of the power converter; (2) Higher energy storage capacitor voltage is required; (3) The increase of filter inductance increases the reactance, which leads to increased losses and lower efficiency; (4) Large filter inductance leads to poor high-frequency response

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