CN112415266A - Method for extracting load harmonic current of active power filter - Google Patents

Method for extracting load harmonic current of active power filter Download PDF

Info

Publication number
CN112415266A
CN112415266A CN202010318436.0A CN202010318436A CN112415266A CN 112415266 A CN112415266 A CN 112415266A CN 202010318436 A CN202010318436 A CN 202010318436A CN 112415266 A CN112415266 A CN 112415266A
Authority
CN
China
Prior art keywords
current
fundamental
load
active power
instantaneous
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202010318436.0A
Other languages
Chinese (zh)
Other versions
CN112415266B (en
Inventor
陈冬冬
郭隐彪
颜文煅
钟明灯
程蔚
朱同波
李智敏
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Minnan University of Science and Technology
Original Assignee
Minnan University of Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minnan University of Science and Technology filed Critical Minnan University of Science and Technology
Priority to CN202010318436.0A priority Critical patent/CN112415266B/en
Publication of CN112415266A publication Critical patent/CN112415266A/en
Application granted granted Critical
Publication of CN112415266B publication Critical patent/CN112415266B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
    • G01R23/16—Spectrum analysis; Fourier analysis
    • G01R23/165—Spectrum analysis; Fourier analysis using filters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/20—Active power filtering [APF]

Landscapes

  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention relates to the field of power technology application, in particular to a method for extracting load harmonic current of an active power filter, which comprises the following steps: dividing the load current into fundamental wave and harmonic wave, defining instantaneous values of sinusoidal current and sinusoidal voltage so as to calculate and obtain instantaneous fundamental wave active power and instantaneous fundamental wave reactive power, calculating an arithmetic mean of a basic period so as to eliminate alternating current component so as to obtain corresponding active power value, reactive power value and double vision power; step two: inducing the PCC voltage filtered by the feedback second-order generalized integrator into complex fundamental wave voltage, and obtaining the amplitude and the phase of the PCC voltage by using a vector method; step three: obtaining the amplitude and the corresponding phase of the fundamental load current; step four: and the instantaneous fundamental current is obtained, and under the condition that the fundamental load current is known, the load harmonic current is obtained by subtracting the load fundamental current from the load current, so that the extraction precision is ensured, and meanwhile, the good dynamic performance is also ensured.

Description

Method for extracting load harmonic current of active power filter
Technical Field
The invention relates to the field of power technology application, in particular to a method for extracting load harmonic current of an active power filter.
Background
The harmonic detection precision is used as a first link of active power filter control, the performance of the harmonic detection precision determines the compensation precision of the SAPF in a steady state and the response speed of the SAPF in a dynamic state, the traditional detection method is that a fundamental current is detected based on an instantaneous reactive power theory, the fundamental active power is subtracted from a load current to obtain a harmonic instruction, an inherent contradiction exists between the low-pass filtering performance and a delay, the cut-off frequency of the low-pass filter is generally selected in a compromise mode, but the inherent defects of the delay and the performance still exist, in the dynamic state, the delay existing in the low-pass filter in an algorithm can cause that a certain fundamental active error exists between the harmonic instruction obtained in the dynamic state and an actual value, and the direct current side of the SAPF in the dynamic state is easy to generate great fluctuation, and the traditional harmonic extraction:
1) the method based on instantaneous reactive power theory generally transforms the load current under a synchronous or static coordinate system through coordinate transformation, at the moment, the fundamental component of the load current is transformed into direct current quantity, the harmonic component is displayed as alternating current quantity, and the harmonic component and harmonic wave are separated by a Low Pass Filter (LPF); however, the algorithm has a certain delay in separating fundamental wave and harmonic wave, which depends on the performance of LPF, and active current is injected in the dynamic process, thereby bringing great harm to the harmonic detection and the application of the detection result.
2) The FFT (fast Fourier transform) algorithm can calculate the frequency spectrums of all frequency points in the Nyquist frequency, the calculation speed is faster than that of the DFT (discrete Fourier transform) for extracting the frequency spectrums of all the frequency points, but when only the frequency spectrums of partial frequency points are required, such as characteristic harmonics within 50 times in most electric power applications, the DFT algorithm can only calculate the required harmonic frequency spectrums, so that the time required by the algorithm is smaller, the required data memory amount is relatively less, and meanwhile, compared with the FFT algorithm, the DFT algorithm has the advantages of more flexible selection of sampling rate and the number of the conversion points, better instantaneity, easier control, simpler operation, more convenient programming realization in a chip and the like.
3) The SDFT (sliding window discrete Fourier transform) algorithm is the optimization of the DFT algorithm, the operation of the DFT algorithm is evenly distributed in each sampling period in a sliding iteration mode, the calculated amount is further reduced, but the SDFT algorithm also has the defect that a dynamic process needs one fundamental wave period for time delay.
Disclosure of Invention
In order to solve the technical problems, the invention provides the method for extracting the load harmonic current of the active power filter, which ensures the extraction precision and also ensures good dynamic performance.
In order to solve the technical problem, the invention provides a method for extracting load harmonic current of an active power filter, which comprises the following steps:
the method comprises the following steps: establishing a circuit for extracting load harmonic current of an active power filter, dividing the load current into fundamental wave and harmonic wave, defining instantaneous values of sinusoidal current and sinusoidal voltage, so as to calculate instantaneous fundamental wave active power and instantaneous fundamental wave reactive power, and calculating an arithmetic mean of a basic period to eliminate alternating current components, so as to obtain corresponding active power value, reactive power value and double vision power;
step two: according to the calculated active power value and reactive power value, the PCC voltage filtered by the feedback second-order generalized integrator is summarized into complex fundamental wave voltage, and the amplitude and the phase of the PCC voltage are obtained by using a vector method;
step three: processing the double vision power in the same way as the step two to obtain the amplitude and the corresponding phase of the fundamental load current;
step four: through the above steps, an instantaneous fundamental current is obtained, and thus, when the fundamental load current is known, the load harmonic current is calculated by subtracting the load fundamental current from the load current.
Preferably, the circuit for extracting the load harmonic current of the active power filter comprises a direct-current side voltage control circuit, a phase-locked loop, a reference harmonic current extraction and current controller, and the reference harmonic current extraction and current controller is formed by direct-current side voltage control and load-related harmonic current reference generation.
Preferably, in the first step, the instantaneous values of the sinusoidal current i (t) and the sinusoidal voltage u (t) are defined as:
Figure RE-GDA0002909989320000031
Figure RE-GDA0002909989320000032
the phase difference between the two is as follows:
Figure RE-GDA0002909989320000033
thus, the load-side instantaneous power is:
Figure RE-GDA0002909989320000034
the above equation can be expressed as:
Figure RE-GDA0002909989320000035
the first part of the above equation describes the instantaneous fundamental active power and the second part describes the instantaneous fundamental reactive power, and the ac component can be eliminated by calculating the arithmetic mean of one fundamental period from the above equation, so as to obtain the corresponding active power value:
Figure RE-GDA0002909989320000036
to determine the fundamental reactive power, a 90 ° phase shifted quadrature component of the voltage is required:
Figure RE-GDA0002909989320000041
similar to calculating active power:
Figure RE-GDA0002909989320000042
therefore, the reactive power can be obtained as follows:
Figure RE-GDA0002909989320000043
the calculation of the fundamental active power and reactive power is done with a moving average filter of N values, corresponding to the time of the fundamental period, so that the calculation is not affected by harmonics in the load current, since the harmonics occur in integer multiples of the fundamental and are eliminated by the moving average filter;
can calculate the active and reactive power P of the fundamental wave1,L,μAnd Q1,L,μThey can be considered as a double vision power:
S 1,L,u＝P1,L,u+j·Q1,L,u
preferably, in step two, the PCC voltage filtered by the feedback second-order generalized integrator may be summarized as a complex fundamental voltage:
u 1,PCC,u＝u1,PCC,u+j·u1,⊥,PCC,u
using the vector method, the amplitude and phase of these two quantities can be determined, which for PCC voltages is:
Figure RE-GDA0002909989320000044
Figure RE-GDA0002909989320000051
preferably, in step three, the double vision power is processed as in step two, and the amplitude of the fundamental load current is:
Figure RE-GDA0002909989320000052
the corresponding phases are:
Figure RE-GDA0002909989320000053
preferably, in step four, the above steps are summarized, so that the instantaneous fundamental current is:
Figure RE-GDA0002909989320000054
thus, when the fundamental load current is known, the load harmonic current can be calculated by subtracting the load fundamental current from the load current:
iL,H,u(t)＝iL,u(t)-iL,1,u(t)。
by adopting the technical scheme, the invention has the beneficial effects that: the method provided by the invention can accurately extract the harmonic current in the load, and in a basic period after the load current is changed for the first time, the extraction result of the harmonic current can reach a steady state, so that the extraction precision is ensured, and meanwhile, the good dynamic performance is also ensured.
Drawings
FIG. 1 is a control block diagram of an active power filter according to the present invention;
FIG. 2 is a block diagram of a power calculation circuit of the present invention;
FIG. 3 is a block diagram of a complex view power and complex fundamental voltage vector calculation circuit according to the present invention;
FIG. 4 is a waveform illustrating the dynamic performance of harmonic current extraction according to the present invention.
Detailed Description
The invention is described in further detail below with reference to the following figures and detailed description:
as shown in the attached figure 1, the method for extracting the load harmonic current of the active power filter comprises a direct current side voltage control, a phase-locked loop, a reference harmonic current extraction and current controller, wherein the reference harmonic current extraction and current controller is formed by direct current side voltage control and load-related harmonic current reference generation, and the basic idea of the current reference generation is to divide the load current into a fundamental wave iL,1,μAnd harmonic iH,L,μ:
iL,u(t)＝iL,1,u(t)+iL,H,u(t)；
The extraction method comprises the following steps:
defining the instantaneous values of the sinusoidal current i (t) and the sinusoidal voltage u (t) as:
Figure RE-GDA0002909989320000061
Figure RE-GDA0002909989320000062
the phase difference between the two is as follows:
Figure RE-GDA0002909989320000063
thus, the load-side instantaneous power is:
Figure RE-GDA0002909989320000064
the above equation can be expressed as:
Figure RE-GDA0002909989320000065
the first part of the above equation describes the instantaneous fundamental active power and the second part describes the instantaneous fundamental reactive power. The ac component can be eliminated by calculating the arithmetic mean of one fundamental cycle from the above equation, resulting in the corresponding value of the active power:
Figure RE-GDA0002909989320000071
to determine the fundamental reactive power, a 90 ° phase shifted quadrature component of the voltage is required:
Figure RE-GDA0002909989320000072
similar to calculating active power:
Figure RE-GDA0002909989320000073
therefore, the reactive power can be obtained as follows:
Figure RE-GDA0002909989320000074
thus, the power calculation can be implemented as shown in the structure of fig. 2, the quadrature component of the voltage is provided by the feedback second order generalized integrator, which is tuned to the fundamental frequency, since the phase locked loop can also adapt to frequency variations, since the PCC voltage only changes slowly, only a low dynamic behavior filtering PCC voltage is needed and the feedback second order generalized integrator can tune a very narrow band, thus both providing harmonic-free voltages;
the calculation of the fundamental active power and reactive power is done with a moving average filter of N values, corresponding to the time of the fundamental period, so that the calculation is not affected by harmonics in the load current, since the harmonics occur in integer multiples of the fundamental and are eliminated by the moving average filter;
can calculate the active and reactive power P of the fundamental wave1,L,μAnd Q1,L,μThey can be considered as diplopia in power:
S 1,L,u＝P1,L,u+j·Q1,L,u
similarly, the PCC voltage filtered by the feedback second-order generalized integrator can be summarized as a complex fundamental voltage:
u 1,PCC,u＝u1,PCC,u+j·u1,⊥,PCC,u
as shown in fig. 3, the double-vision power and the complex fundamental voltage provide the input of the current reference power supply;
using the vector method, the amplitude and phase of these two quantities can be determined, which for PCC voltages is:
Figure RE-GDA0002909989320000081
Figure RE-GDA0002909989320000082
the double vision power is similarly processed, and the amplitude of the fundamental load current is:
Figure RE-GDA0002909989320000083
the corresponding phases are:
Figure RE-GDA0002909989320000084
it can thus be obtained that the instantaneous fundamental current is:
Figure RE-GDA0002909989320000085
thus, when the fundamental load current is known, the load harmonic current can be calculated by subtracting the load fundamental current from the load current:
iL,H,u(t)＝iL,u(t)-iL,1,u(t)。
the dynamic performance of the harmonic current extraction is shown in figure 4, the method provided by the invention can accurately extract the harmonic current in the load, the harmonic current extraction result can reach a steady state in a basic period after the load current is changed for the first time, and the experimental result shows that the method has the characteristic of quickly and accurately extracting the harmonic current of the load.
The present invention has been described in detail with reference to the specific embodiments, but these should not be construed as limitations of the present invention. Many variations and modifications may be made by one of ordinary skill in the art without departing from the principles of the present invention, which should also be considered as within the scope of the present invention.

Claims (6)

1. A method for extracting load harmonic current of an active power filter is characterized by comprising the following steps:
the method comprises the following steps: establishing a circuit for extracting load harmonic current of an active power filter, dividing the load current into fundamental wave and harmonic wave, defining instantaneous values of sinusoidal current and sinusoidal voltage, so as to calculate instantaneous fundamental wave active power and instantaneous fundamental wave reactive power, and calculating an arithmetic mean of a basic period to eliminate alternating current components, so as to obtain corresponding active power value, reactive power value and double vision power;
step two: according to the calculated active power value and reactive power value, the PCC voltage filtered by the feedback second-order generalized integrator is summarized into complex fundamental wave voltage, and the amplitude and the phase of the PCC voltage are obtained by using a vector method;
step three: processing the double vision power in the same way as the step two to obtain the amplitude and the corresponding phase of the fundamental load current;
step four: through the above steps, an instantaneous fundamental current is obtained, and thus, when the fundamental load current is known, the load harmonic current is calculated by subtracting the load fundamental current from the load current.
2. The active power filter load harmonic current extraction method as claimed in claim 1, wherein the active power filter load harmonic current extraction circuit comprises a dc side voltage control, a phase locked loop, a reference harmonic current extraction and current controller, and the reference harmonic current extraction and current controller is composed of a dc side voltage control and a load-related harmonic current reference generation.
3. The method as claimed in claim 1, wherein in the step one, the instantaneous values of the sinusoidal current i (t) and the sinusoidal voltage u (t) are defined as:
Figure RE-FDA0002658772870000021
Figure RE-FDA0002658772870000022
the phase difference between the two is as follows:
Figure RE-FDA0002658772870000023
thus, the load-side instantaneous power is:
Figure RE-FDA0002658772870000024
the above equation can be expressed as:
Figure RE-FDA0002658772870000025
the first part of the above equation describes the instantaneous fundamental active power and the second part describes the instantaneous fundamental reactive power, and the ac component can be eliminated by calculating the arithmetic mean of one fundamental period from the above equation, so as to obtain the corresponding active power value:
Figure RE-FDA0002658772870000026
to determine the fundamental reactive power, a 90 ° phase shifted quadrature component of the voltage is required:
Figure RE-FDA0002658772870000027
similar to calculating active power:
Figure RE-FDA0002658772870000028
therefore, the reactive power can be obtained as follows:
Figure RE-FDA0002658772870000031
the calculation of the fundamental active power and reactive power is done with a moving average filter of N values, corresponding to the time of the fundamental period, so that the calculation is not affected by harmonics in the load current, since the harmonics occur in integer multiples of the fundamental and are eliminated by the moving average filter;
can calculate the active and reactive power P of the fundamental wave1,L,μAnd Q1,L,μThey can be considered as a double vision power:
S 1,L,u＝P1,L,u+j·Q1,L,u
4. the method according to claim 1, wherein in the second step, the PCC voltage filtered by the feedback second-order generalized integrator is summarized as a complex fundamental voltage:
u 1,PCC,u＝u1,PCC,u+j·u1,⊥,PCC,u
using the vector method, the amplitude and phase of these two quantities can be determined, which for PCC voltages is:
Figure RE-FDA0002658772870000032
Figure RE-FDA0002658772870000033
5. the method according to claim 1, wherein in step three, the double vision power is processed as in step two, and the amplitude of the fundamental load current is:
Figure RE-FDA0002658772870000041
the corresponding phases are:
Figure RE-FDA0002658772870000042
6. the method of claim 1, wherein in step four, the instantaneous fundamental current is obtained by the following steps:
Figure RE-FDA0002658772870000043
thus, when the fundamental load current is known, the load harmonic current can be calculated by subtracting the load fundamental current from the load current:
iL,H,u(t)＝iL,u(t)-iL,1,u(t)。
CN202010318436.0A 2020-04-21 2020-04-21 Active power filter load harmonic current extraction method Active CN112415266B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010318436.0A CN112415266B (en) 2020-04-21 2020-04-21 Active power filter load harmonic current extraction method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010318436.0A CN112415266B (en) 2020-04-21 2020-04-21 Active power filter load harmonic current extraction method

Publications (2)

Publication Number Publication Date
CN112415266A true CN112415266A (en) 2021-02-26
CN112415266B CN112415266B (en) 2023-10-27

Family

ID=74844062

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010318436.0A Active CN112415266B (en) 2020-04-21 2020-04-21 Active power filter load harmonic current extraction method

Country Status (1)

Country Link
CN (1) CN112415266B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113848383A (en) * 2021-09-14 2021-12-28 国网河南省电力公司电力科学研究院 Method and system for rapidly calculating fundamental frequency signals of disturbed three-phase unbalanced system

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0739253U (en) * 1993-12-17 1995-07-14 東洋電機製造株式会社 Active filter current detection circuit
CN102253266A (en) * 2011-04-28 2011-11-23 西华大学 Linear filter-based harmonic current detection method in three-phase four-wire system
CN104767202A (en) * 2015-04-17 2015-07-08 西南交通大学 Control method for multi-level active power filter
CN105140922A (en) * 2015-09-08 2015-12-09 中国矿业大学(北京) Three-phase active filter electric current detection algorithm based on CPC power theory
CN105467210A (en) * 2015-12-04 2016-04-06 北京建筑大学 A harmonic detection method
CN106253275A (en) * 2016-08-02 2016-12-21 上海电机学院 A kind of harmonic detecting method based on instantaneous power model and Active Power Filter-APF

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0739253U (en) * 1993-12-17 1995-07-14 東洋電機製造株式会社 Active filter current detection circuit
CN102253266A (en) * 2011-04-28 2011-11-23 西华大学 Linear filter-based harmonic current detection method in three-phase four-wire system
CN104767202A (en) * 2015-04-17 2015-07-08 西南交通大学 Control method for multi-level active power filter
CN105140922A (en) * 2015-09-08 2015-12-09 中国矿业大学(北京) Three-phase active filter electric current detection algorithm based on CPC power theory
CN105467210A (en) * 2015-12-04 2016-04-06 北京建筑大学 A harmonic detection method
CN106253275A (en) * 2016-08-02 2016-12-21 上海电机学院 A kind of harmonic detecting method based on instantaneous power model and Active Power Filter-APF

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
同向前;王党帅;赵叶艳;: "一种新型谐波与无功电流检测方法", 电力系统及其自动化学报 *
许富强 等: "基于二阶广义积分器的谐波电流检测算法", 《水电能源科学》 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113848383A (en) * 2021-09-14 2021-12-28 国网河南省电力公司电力科学研究院 Method and system for rapidly calculating fundamental frequency signals of disturbed three-phase unbalanced system

Also Published As

Publication number Publication date
CN112415266B (en) 2023-10-27

Similar Documents

Publication Publication Date Title
Wang et al. A method to improve the dynamic performance of moving average filter-based PLL
Boyra et al. A review on synchronization methods for grid-connected three-phase VSC under unbalanced and distorted conditions
Ama et al. Phase-locked loop based on selective harmonics elimination for utility applications
CN109067393B (en) Phase locking method, device and equipment of power system
Han et al. A novel synchronization scheme for grid-connected converters by using adaptive linear optimal filter based PLL (ALOF–PLL)
Ghoshal et al. A method to improve PLL performance under abnormal grid conditions
Ullah et al. Comparison of synchronization techniques under distorted grid conditions
CN110557118B (en) Phase locking device and phase locking method
US20030223488A1 (en) Fast phase synchronization and retrieval of sequence components in three-phase networks
Meral Improved phase-locked loop for robust and fast tracking of three phases under unbalanced electric grid conditions
JP5470677B2 (en) Method for detecting fundamental wave component of single-phase AC signal
CN116093953B (en) Phase-locked loop control method, phase-locked loop, inverter and storage medium
CN111817713B (en) High-voltage direct-current phase-locked loop capable of rapidly synchronizing voltage phases under symmetric faults and method
Devi et al. Phase locked loop for synchronization of inverter with electrical grid: A survey
Chedjara et al. A fast and robust reference current generation algorithm for three-phase shunt active power filter
CN112583402B (en) Phase locking method, phase-locked loop, three-phase grid-connected system and computer storage medium
CN109861564B (en) Energy storage load network side rectifier voltage balance control method and system
CN112415266B (en) Active power filter load harmonic current extraction method
Arricibita et al. Simple and robust PLL algorithm for accurate phase tracking under grid disturbances
Xie et al. A method to improve the transient response of dq-frame cascaded delayed-signal-cancellation PLL
Ko et al. A new PLL system using full order observer and PLL system modeling in a single phase grid-connected inverter
Silva et al. A robust phase-locked loop against fundamental frequency deviations and harmonic distortions
CN111786390B (en) Vector repetition control method and system based on harmonic sequence extraction
CN113098015B (en) Method and device for suppressing low-order harmonic of network side current of single-phase rectifier
Sun et al. An Improved $\alpha\beta $-EPLL Based on Active Disturbance Rejection Control for Complicated Power Grid Conditions

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant