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A harmonic current prediction method for compensating control delay

A harmonic current and compensation control technology, which is applied in the field of harmonic current compensation, can solve problems such as large amount of calculation, and achieve the effects of moderate calculation amount, flexible prediction algorithm, and improved prediction accuracy

Inactive Publication Date: 2009-02-11
TSINGHUA UNIV
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  • Application Information

AI Technical Summary

Problems solved by technology

The adaptive FIR predictive filtering algorithm can predict the harmonic current signal one sampling period in advance, but the existing algorithms are too computationally intensive to be implemented under the existing controller hardware conditions

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  • A harmonic current prediction method for compensating control delay
  • A harmonic current prediction method for compensating control delay
  • A harmonic current prediction method for compensating control delay

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Embodiment Construction

[0055] The present invention uses a polynomial composed of a series of harmonic current signals to fit the nonlinear load current so as to realize the prediction of the harmonic current. Its principle block diagram is as follows Figure 4 As shown, firstly measure the instantaneous value I of the grid load current in real time tk , and at the same time get the current sampling time t through the phase-locked loop k The phase angle of the grid voltage wt k ; Perform low-pass filtering on the sampled value of the instantaneous current value: according to the grid voltage phase angle wt at the current sampling moment k Generate the first input sequence X(k):

[0056] X(k)=[cosh 1 wt k , sinh 1 wt k , cosh 2 wt k , sinh 2 wt k ,..., cosh n wt k , sinh n wt k ]

[0057] where h 1 , h 2 ,...,h n Respectively, the characteristic harmonic times of the grid load current;

[0058] Predict the sampled value of load current in the power grid at the current moment ...

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Abstract

The invention is concerned with the harmonic current prediction method for compensating the controlling time-lapse, belongs to the harmonic current compensation technique field. Firstly, it measures the loading current instantaneous value in real time and low passes the filtering, and gets the phase corner of the electric-net voltage by phase-locked loop at the same time; predicts the current volume of the sampling time currently according to the electricity-net current phase corner and the fitting parameter vector; adjusts the fitting parameter vector according to the predicted error; then, according to the adjusted fitting parameter vector, the electricity-net voltage phase corner and the requested compensatory controlling time-lapse, it can predict the loading current volume of the tk+DeltaT time; and predicts the request compensatory harmonic current signal of the tk+DeltaT at last.

Description

technical field [0001] The invention relates to a harmonic current prediction method for compensating control delay, especially suitable for the prediction of dynamic impact load current, and belongs to the technical field of harmonic current compensation. Background technique [0002] The digital current controller of pulse-width-modulated voltage-source converter is one of the current research hotspots, but in the digital control, A / D sampling, control quantity calculation and PWM output and other links will inevitably introduce delays, resulting in no matter Whichever current control algorithm is adopted, the output current of the converter will always lag behind the command current. When the controller adopts the deadbeat control algorithm, the state observer can be used to compensate the calculation delay of the controller, so that the control quantity can be output without delay, but even so, the output current of the converter will still lag behind the command current...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/01H02J1/12
CPCY02E40/40
Inventor 谭甜源姜齐荣韩英铎
Owner TSINGHUA UNIV