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Instructional current detection algorithm and system based on Kalman filtering

A Kalman filter, command current technology, applied in circuit devices, complex mathematical operations, harmonic reduction devices, etc., can solve the problems of three-phase unbalance, large delay, and reduced tracking accuracy, and achieve three-phase amplitude. The effect of small fluctuation, fast compensation speed and fast detection speed

Inactive Publication Date: 2019-04-26
UNIV OF JINAN +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] With the development and application of power electronic technology, power electronic equipment is widely used in three-phase four-wire power system, which makes harmonic pollution more and more serious, resulting in increased power grid loss and reduced service life of electrical equipment.
Three-phase load connection is very easy to be asymmetrical, which makes the three phases unbalanced and generates neutral current. If the neutral current is too large, it will burn the power equipment
[0003] Traditional command current detection algorithms include fast Fourier transform (FFT) algorithm and discrete Fourier transform (DFT) algorithm in the frequency domain, but due to the complexity of the algorithm and the large amount of calculation, the delay is relatively large; In the domain, there are mainly i based on the theory of instantaneous reactive power p -i q law and i d -i q method, the Butterworth filter (ButterworthFilter, BF) is commonly used in the algorithm for i p (or i d ) and i q Perform filtering to obtain the DC component, and then perform inverse transformation, but the inherent delay characteristics of BF itself make the detection real-time performance relatively poor
[0004] The existing technology proposes that the comprehensive use of the mean filter and BF can obtain good detection accuracy and good dynamic response, but using two filters at the same time increases the complexity of the algorithm; the existing technology uses a variable step size LMS algorithm to achieve i p _i q The function of the low-pass filter in theory uses the autocorrelation function of the current error and the last error to control the update of the step size, which eliminates the interference of noise to a certain extent, but the tracking waveform will produce a certain steady-state offset error, and when When the load changes suddenly, the tracking accuracy will decrease accordingly

Method used

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  • Instructional current detection algorithm and system based on Kalman filtering
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  • Instructional current detection algorithm and system based on Kalman filtering

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Embodiment 1

[0047] In one or more implementations, a Kalman filter-based instruction current detection algorithm is disclosed, such as figure 1 Shown, including: first for i a , i b , i c Carry out the clark transform and C 2s / 2r Transform to get i p , i q . based on i p _i q After establishing the discrete system state equation and measurement equation, use the Kalman filter to i p , i qPerform filtering to obtain the DC component, obtain the fundamental positive sequence current after inverse transformation, and then subtract it from the load current to obtain the total compensation current.

[0048] The instantaneous value of load current i in a three-phase load a , i b , i c Measured by current transformer. The load current in a three-phase asymmetrical load system is expressed as follows:

[0049]

[0050] The subscripts 1, 2, and 0 represent positive sequence, negative sequence, and zero sequence components respectively; I 0 =I 0 nsin(hwt+θ 0n ) is the zero-seque...

Embodiment 2

[0112] A Kalman filter-based instruction current detection system disclosed in one or more embodiments includes a server, the server includes a memory, a processor, and a computer program stored on the memory and operable on the processor, so that When the processor executes the program, the Kalman filter-based instruction current detection method described in the first embodiment is implemented.

Embodiment 3

[0114] A computer-readable storage medium disclosed in one or more implementations has a computer program stored thereon, and when the program is executed by a processor, the method for detecting an instruction current based on a Kalman filter described in Embodiment 1 is executed.

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Abstract

The invention discloses an instructional current detection algorithm and system based on Kalman filtering. The method comprises the following steps: measuring instantaneous load current in three-phaseload; using clark transform to transform the instantaneous current in the three-phase load into an alpha-beta two-phase orthogonal coordinate system, obtaining instantaneous active current ip and reactive current iq through coordinate transformation; establishing a discrete system state equation and a measurement equation based on ip_iq; filtering ip and iq by using a Kalman filter to obtain a direct current component; obtaining fundamental wave positive sequence current through inverse coordinate transformation, and subtracting the fundamental wave positive sequence current from the load current to obtain a total compensation current. The method can quickly track the change of the load current and detect the compensation current instruction reference signal; and compared with an algorithm using Butterworth LPF, the method has the advantages of high detection speed, good real-time performance and small three-phase amplitude fluctuation, so that the compensation speed is higher, and the effect is more reliable.

Description

technical field [0001] The invention relates to a Kalman filter command current detection algorithm and system. Background technique [0002] With the development and application of power electronic technology, power electronic equipment is widely used in three-phase four-wire power system, which makes harmonic pollution more and more serious, resulting in increased power grid loss and reduced service life of electrical equipment. The connection of three-phase loads is very easy to be asymmetrical, which makes the three phases unbalanced and generates zero-line current. If the zero-line current is too large, it will burn the power equipment. Most power quality regulators have the functions of compensating harmonics and compensating three-phase unbalance to improve power quality. The real-time detection of the compensation current command signal is one of the main factors affecting the compensation effect of the power quality conditioner. [0003] Traditional command curren...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/18H02J3/26H02J3/01G06F17/16
CPCG06F17/16H02J3/01H02J3/18H02J3/26H02J2203/20Y02E40/30Y02E40/40Y02E40/50
Inventor 程新功李发磊张永峰宗西举张静亮殷文月于明珠邵振振赵义上
Owner UNIV OF JINAN