Simplification control method of parallel connection type active electric power filter

Abstract

The invention discloses a simplification control method of a parallel connection type active electric power filter. The method comprises steps of inputting a difference value of direct-current side reference voltage and capacitance voltage into a PI controller; acquiring a three-phase loading current signal through a current transformer; obtaining load current under a dq axis through abc / dq conversion; obtaining load fundamental current through a low-pass filter; adjusting the d-axis fundamental current; allowing the adjusted load fundamental current to be subjected to dq / abc conversion and outputting three-phase load fundamental current; inputting the difference value of the output current and power grid current into a current controller; and feeding the output of the current controller into an SVPWM driving module so as to generate a switch signal to control a three-phase full-bridge inverter to generate a compensation signal. Thus, tracking of the load fundamental current by the power grid current is achieved and harmonic wave compensation is indirectly achieved.

Description

technical field [0001] The invention belongs to the field of power electronics, and in particular relates to a simplified control method of a parallel active power filter. Background technique [0002] With the wide application of nonlinear loads, the problem of harmonic pollution in power systems is becoming more and more serious. Traditional harmonic suppression methods have been difficult to meet the needs of modern power systems, and active power filters (APF) have received widespread attention as a new type of harmonic compensation device. [0003] The focus of traditional active power filter research has been on the control of load harmonics, and many harmonic detection algorithms and harmonic current control methods have been proposed. However, the advantages and disadvantages of the harmonic detection method will significantly affect the compensation effect of the active power filter, and it is also a major difficulty to realize the control of the load harmonic curr...

AI Technical Summary

Problems solved by technology

However, the advantages and disadvantages of the harmonic detection method will significantly affect the compensation effect of the active power filter, and it is also a major difficulty to realize the control of the load harmonic current

For example, although hysteresis control is simple to implement and has good dynamic response, its serious disadvantage is that the switching frequency is not fixed. Of course, some scholars have proposed a hysteresis control method with a fixed frequency, but most of them have the practical problem of controlling the load and being difficult to realize; For example, cascaded proportional resonance control, since most of the nonlinear loads are rectifying loads, the harmonic current order is mainly 6k±1 times, so a large number of resonant controllers can be cascaded to achieve harmonic compensation, but the higher the control accuracy The more resonant controllers that need to be cascaded, the more cascaded resonant controllers, the higher the requirements for the digital processor, and the more difficult it is to realize; moreover, there are other orders of harmonic currents in practical applications, so the cascaded It is also difficult for the proportional resonant controller to compensate the harmonic current well

Most of the direct harmonic current control methods also have such problems

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