Novel UPS capacitive non-linear load compensation control strategy

Abstract

The invention discloses a novel UPS capacitive non-linear load compensation control strategy. The control strategy comprises capacitive non-linear load, a controller, a phase-locked loop (PLL), a power device, and an active power filter (APF). The control strategy adopts the selective harmonic wave compensation scheme based on FFT, and improves a parallel active filter, and changes the original full-bandwidth compensation into limited bandwidth compensation and compensation having selective harmonic wave so as to eliminate the system resonance. The invention is advantageous in that the activepower filter detects load current through a current transformer and extracts the harmonic wave component in the load current through the internal DSP calculating, and controls an inverter to generateharmonic wave current which has the same size as and different direction to the load harmonic wave to be injected into the power grid through sending PWM signal to the internal IGBT, and thereby the aim of filtering can be achieved.

Description

technical field [0001] The invention belongs to the field of harmonic current control, in particular to an FFT-based UPS capacitive nonlinear load compensation control strategy. Background technique [0002] At present, a large number of electronic equipment used, such as high-power thyristor phase-controlled rectifier circuits, AC inverters, industrial arc furnaces, switching power supplies and other nonlinear loads, generate a large number of harmonics, resulting in serious grid pollution. As an effective passive harmonic control scheme, shunt active power filter (Shunt Active Power Filter) has been paid more and more attention in recent years. [0003] When the shunt active power filter works, it is usually controlled as a harmonic current source, which is suitable for compensating current-type harmonic sources, such as resistive-inductive loads, but not suitable for compensating voltage-type harmonic sources, such as capacitor filter-type rectifier loads. However, in th...

AI Technical Summary

Problems solved by technology

[0004] The current method is to use the control method of detecting the grid voltage to achieve the purpose of harmonic damping, but the control method is to achieve harmonic damping when the grid voltage is relatively ideal, and does not take into account the influence of the actual grid voltage distortion on the site.

Through improvement, scholars have designed a new control strategy for compensating load current harmonics and damping harmonic amplification, and verified the feasibility and effectiveness through experiments, but the proposed new control strategy algorithm is relatively complicated and is based on Realized under the premise of parallel hybrid active filter, it cannot be directly applied to the current harmonic oscillation suppression

Images