Active power quality adjuster

Abstract

The invention relates to an active power quality adjuster, consisting of a fundamental wave compensation part and a harmonic wave compensation part, and the two parts compensate fundamental current and harmonic current respectively. An H-bridge cascade multilevel inverter and a fundamental wave connection inductance are connected in series at the fundamental wave compensation part, so that reactive compensation and unbalanced load compensation can be dynamically carried out; the H-bridge cascade multilevel inverter and a unituning passive filter are connected in series to form the harmonic wave compensation part which is connected across the two ends of the fundamental wave connection inductance. Therefore, the power quality adjuster can lower switching frequency and loss of the H-bridge cascade multilevel inverter at the fundamental wave compensation part greatly on one hand, and only a fraction of fundamental current passes the harmonic wave compensation part and the whole part only undertakes fundamental voltage of the fundamental wave connection inductance without undertaking fundamental voltage on the other hand, thereby effectively reducing the capacity of the H-bridge inverter and the withstand voltage at the harmonic wave compensation part.

Description

technical field [0001] The invention relates to the field of power systems, in particular to an active power quality regulator. Background technique [0002] With the wide application of power electronic devices in the industry, the problem of harmonic pollution in the power grid is becoming more and more serious. Harmonics not only affect the normal operation of electrical equipment, but also bring hidden dangers to the safe and economic operation of the power grid, and also cause electromagnetic interference to the signal system, affecting the normal operation. In a power system, not only network elements consume reactive power, but most loads also consume reactive power. In order to improve the power factor, reduce the capacity, stabilize the grid voltage, and compensate the unbalanced load, the reactive power required by the system needs to be reasonably compensated. [0003] Parallel Active Filter (APF) and Parallel Hybrid Active Filter (HAPF) are the two main harmoni...

AI Technical Summary

Problems solved by technology

This reduces the capacity of the active filter to a certain extent, but the harmonic compensation adopts the inductance injection method, which requires the DC side voltage of the active filter to be greater than the fundamental wave voltage on the fundamental wave inductor. As the frequency of harmonic injection increases , the harmonic tracking ability becomes worse, and the injected harmonic current will form a circulating current in the fundamental wave connection inductance, which will affect the compensation effect

[0005] In the structure of the present invention, based on the idea of ​​fundamental wave current and harmonic current decoupling compensation, the harmonic compensation part composed of the active filter and the passive filter branch in series is connected across the two ends of the fundamental wave connection inductance To reduce the topology of the active filter capacity, the same or similar technology has not been seen at home and abroad

Images