Control method for three-phase three-wire active filtering apparatus
A filter device, three-phase three-wire technology, applied in harmonic reduction devices, AC networks to reduce harmonics/ripples, etc., can solve the problem of increasing the amount of calculation, unable to obtain the information of each harmonic current, and unable to easily detect Problems such as negative sequence current
Inactive Publication Date: 2014-11-26
湖北通益电气有限公司
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Problems solved by technology
The problem with this detection method is: this detection method needs to undergo multiple coordinate transformations; it cannot easily detect the negative sequence current; it can only detect the total harmonic current, but cannot obtain the information of each harmonic current
However, to detect harmonics in this way, it is necessary to perform FFT transformation and inverse transformation on the three-phase load current one by one (at least two phases), which requires a large amount of calculation.
When tracking and controlling the compensation current, due to the direct coupling of the three phases, it cannot be decoupled, which affects the compensation effect and reduces the control accuracy.
In addition, if you need to use space vector control (SVPWM), you need to do another coordinate transformation, which further increases the amount of calculation
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[0056] The present invention will be further described with reference to the drawings.
[0057] Such as figure 1 The control device of the three-phase three-wire active filter device of the present invention shown in the dashed line box consists of the following three parts: the control device of the three-phase three-wire active filter device consists of the following three parts: load current detection and analysis part, compensation Command current calculation and synthesis part, compensation current tracking control part, the load current detection and analysis part such as figure 2 Shown by C 3 / 2 Transformation part, periodic sampling part, complex number construction part and fast Fourier transform part, C 3 / 2 The transform part, the periodic sampling part, the complex number construction part and the fast Fourier transform part are connected in sequence. The calculation and synthesis part of the compensation command current is as follows image 3 As shown, it consists of a...
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The invention relates to a control method for a three-phase three-wire active filtering apparatus. The control method comprises: a load current detection and analysis portion analyzes a current generated in a load to obtain contents of each subharmonic and sizes of various components in a fundamental wave; a compensation instruction current calculating synthesis portion, first according to a compensation requirement, calculates a frequency domain signal of a compensation instruction current , then, converts the frequency domain signal into a time domain signal, and obtains a present instruction current; and a compensation current tracking control portion compares a present instruction current signal with a detected practical compensation current signal and calculates to generate a control voltage vector signal, then, converts the control voltage vector signal into a driving signal to drive a semiconductor power switching device to obtain the goal of tracking and controlling a compensation current. According to the method, no interphase coupling exists, so current tracking control is more accurate; and the method can easily detect active and reactive components, and positive and negative sequence currents of a load fundamental current with simple calculation, thereby greatly reducing the expenditure of a CPU.
Description
Technical field [0001] The invention relates to the field of harmonic control in power systems, and more specifically to a novel harmonic detection and tracking control method for a three-phase three-wire parallel active power filter. Background technique [0002] With the increasing of non-linear loads in the power grid, the harmonics generated by the power grid are more and more serious. At present, harmonic suppression devices based on passive filters and active power filters are mainly used to control grid pollution. [0003] Passive filters are widely used because of their simple structure, low cost, and mature technology, but they have many inherent shortcomings that are difficult to overcome. Active power filter (APF) is a fast and dynamic power electronic device that compensates for harmonics. Compared with passive filters, it has many advantages: filtering performance is not affected by system impedance; Resonance occurs; harmonics are controlled dynamically, and the res...
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IPC IPC(8): H02J3/01
CPCY02E40/40
Inventor罗斐徐前罗运松李达义
Owner湖北通益电气有限公司