Harmonic suppression circuit of low-voltage distribution network

Abstract

The invention discloses a harmonic suppression circuit for a low-voltage distribution network. The harmonic suppression circuit comprises a voltage sampling circuit, a harmonic processing module, an error amplifier EA1, a multiplier M1, a comparator and an RS trigger, wherein the voltage sampling circuit is composed of a resistor R1 and a resistor R2; wherein the harmonic processing module is composed of an analog-to-digital converter, a phase-locked loop module, a Fourier analysis module, a multiplier M2, an adder A1 and a digital-to-analog converter; and a harmonic compensation function is realized through combination of current control and a harmonic processing module. The harmonic suppression circuit has the characteristic of high power factor and also has a harmonic compensation function. When the method is applied to a low-voltage local power distribution network, centralized harmonic suppression schemes such as an active filter can be optimized and even replaced.

Description

technical field [0001] The invention belongs to the technical field of power converter control, in particular to a low-voltage distribution network harmonic suppression circuit. Background technique [0002] The low-voltage side of the distribution network contains various loads, most of which are nonlinear loads. When the current flows through a nonlinear load, the relationship with the applied voltage is not linear, and a non-sinusoidal current with harmonic components will be generated. In practical applications, harmonics may be generated by various power electronic conversion circuits, such as uncontrolled rectifiers, thyristor chopping, etc. Harmonics is a kind of power quality problem in power distribution system, which may cause damage to power equipment and malfunction of protection devices. figure 1 It is the connection relationship of the parallel active power filter (Active Power Filter, APF) in the nonlinear load circuit, which generates a current with the sam...

AI Technical Summary

Problems solved by technology

However, when non-harmonic suppression non-linear loads exist in the distribution network, it will cause voltage distortion on the input side of the harmonic suppression circuit, and then increase the current harmonics on the power supply side, making the harmonic suppression circuit work in an unrated state , which reduces the efficiency of the power conversion device

[0004] The traditional APF centralized harmonic control method, because its distribution characteristics do not match the distribution of harmonic sources, the compensation result is easily affected by factors such as circuit parameters

The local harmonic control method of the traditional harmonic suppression circuit is difficult to effectively eliminate the harmonic interference on the grid side of the distribution network, and cannot meet the power supply demand of places with high requirements on power quality

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