CN113467418B - Method for measuring performance index of control loop - Google Patents

Method for measuring performance index of control loop Download PDF

Info

Publication number
CN113467418B
CN113467418B CN202110723044.7A CN202110723044A CN113467418B CN 113467418 B CN113467418 B CN 113467418B CN 202110723044 A CN202110723044 A CN 202110723044A CN 113467418 B CN113467418 B CN 113467418B
Authority
CN
China
Prior art keywords
est
signal
frequency
control loop
omega
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.)
Active
Application number
CN202110723044.7A
Other languages
Chinese (zh)
Other versions
CN113467418A (en
Inventor
刘青
王嘉晨
韩伟健
辛振
陈建良
明磊
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.)
Hebei University of Technology
Original Assignee
Hebei University of 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 Hebei University of Technology filed Critical Hebei University of Technology
Priority to CN202110723044.7A priority Critical patent/CN113467418B/en
Publication of CN113467418A publication Critical patent/CN113467418A/en
Application granted granted Critical
Publication of CN113467418B publication Critical patent/CN113467418B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B23/00—Testing or monitoring of control systems or parts thereof
    • G05B23/02—Electric testing or monitoring
    • G05B23/0205—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults
    • G05B23/0218—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults characterised by the fault detection method dealing with either existing or incipient faults
    • G05B23/0256—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults characterised by the fault detection method dealing with either existing or incipient faults injecting test signals and analyzing monitored process response, e.g. injecting the test signal while interrupting the normal operation of the monitored system; superimposing the test signal onto a control signal during normal operation of the monitored system
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/20—Pc systems
    • G05B2219/24—Pc safety
    • G05B2219/24065—Real time diagnostics

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Measurement Of Resistance Or Impedance (AREA)

Abstract

The invention discloses a method for measuring performance indexes of a control loop, which adopts the idea of dynamic frequency searching, does not need to sweep frequency like the traditional frequency response method and has high detection speed. The performance index measuring method can measure the cut-off frequency and the phase angle margin of the control loop, and provides valuable reference information for the closed loop optimization design of the control system.

Description

Method for measuring performance index of control loop
Technical Field
The invention belongs to the technical field of control, and particularly relates to a method for measuring performance indexes of a control loop.
Background
Based on the automatic control theory, the controlled object in the field of electrical engineering is often simplified into a linear steady system. Such systems facilitate mathematical modeling and analysis, and their control systems are typically cascaded from a single or multiple control loops. The control loops are independent of each other and controlled by respective loop regulators (linear or non-linear). Therefore, the design of the loop regulator is the core of the whole control system design, and the given performance indexes (namely, the loop bandwidth and the phase angle margin) need to be followed to meet the expected dynamic and static performance requirements of the system. However, due to the influence of system model errors, parameter disturbance and other factors, an error always exists between the design performance index and the actual performance index of the regulator, and the dynamic and static performance requirements of the control system are difficult to accurately meet. The fundamental reason is that the design idea of the loop regulator for deducing the open-loop transfer function according to the model belongs to an open-loop design method, and the feedback of actual loop performance index information is lacked. In view of this, accurately measure the actual performance index information of control loop, to the closed loop optimal design of regulator, the dynamic and static performance guarantee of control system has extremely important meaning.
The measurement of the performance index of the control loop comprises two parts of measurement of control bandwidth and phase angle margin, wherein the control bandwidth reflects the dynamic performance of the control loop, and the phase angle margin represents the stability margin. The phase angle margin can be solved directly by controlling the bandwidth and the open loop transfer function, so the core task of measurement is the measurement of the control bandwidth. The control bandwidth measurement methods commonly used at present can be roughly divided into two types: 1) a step response method; 2) frequency response method. The step response method can only estimate the bandwidth value through an empirical formula, and is not suitable for the condition that the controlled object has resonance. The frequency response method is simple in principle, but is difficult to realize. If the test is carried out by the aid of a dynamic signal analyzer, the frequency sweep data output rate is limited by the baud rate of the serial port, and a large error exists in a bandwidth measured value at high frequency.
Disclosure of Invention
The invention aims to provide a method for measuring performance indexes of a control loop aiming at the defects in the prior art, so as to realize the measurement of the cut-off frequency and the phase angle margin of the control loop and provide important information support for the closed loop optimization design of a control system regulator, thereby ensuring the dynamic and static performance of the control system under the condition of parameter disturbance.
The technical scheme for solving the technical problem is as follows: a method for measuring performance indexes of a control loop is designed, and is characterized by comprising the following steps:
a method for measuring performance indexes of a control loop is characterized by comprising the following steps:
(1) injecting small signals
Injecting a variable-frequency sine wave small signal (x) into the controlled control loopp(jωest) ); from sine-wave small signals (x)p(jωest) Amplitude (| x)p(jωest) I) and angular frequency (omega)est) The injection signal (x) can be obtainedp) Is expressed as xp＝|xp(jωest)|sin(ωestt)；
(2) Extracting a detection signal
Detection signal interfaces are arranged on the left side and the right side of a signal injection point of the control loop and are respectively used for detecting a detection signal (x) on the left side of the signal injection point in real timein(jωest) And the right side detection signal (x)out(jωest) ); left side detection signal (x)in(jωest) And the right side detection signal (x)out(jωest) Respectively extract the current angular frequency (ω) in the detection signal at that time by the SOGIest) Lower left (xin) and right (x) sinusoidal signalsout) The real and imaginary parts of (c); by using
Figure GDA0003577621800000021
Figure GDA0003577621800000022
The left side sinusoidal signal (x) is obtainedin) With the right-hand sinusoidal signal (x)out) Amplitude and phase angle of;
(3) dynamic frequency finding
Intersection (omega) of the open loop transfer function (T) of the control loop with the abscissac) Is the corresponding cut-off frequency; due to T (j omega) est)＝-xout(jωest)/xin(jωest) I.e. at angular frequency (omega)est) In the following, | T | ═ xout|/|xinL, obtaining a left side sine signal (x) in the step (2)in) With the right sinusoidal signal (x)out) Is substituted into the equation, when | T | ═ 1, i.e., | xout(jωest)|＝|xin(jωest) At the current angular frequency (ω |)est) I.e. the cut-off frequency (omega) of the control loopc) (ii) a Cut-off frequency (omega)c) I.e. the bandwidth of the control loop;
when | T | ≠ 1, then at the current angular frequency (ω)est) Next, | xout(jωest) Subtract | xin(jωest) The value obtained by I passes through a PI regulator to obtain an injection signal (x)p) New frequency of
Figure GDA0003577621800000031
Multiplying it by 2 pi to obtain new angular frequency
Figure GDA0003577621800000032
New angular frequency
Figure GDA0003577621800000033
Omega is obtained through an integration link1 estt; according to omega1 estt, will inject signal (x)p) Sin (ω) of (1)estt) is adjusted to sin (ω)1 estt), continuing to execute the process of extracting the detection signal in the step (2), and enabling the frequency to be at the new angular frequency
Figure GDA0003577621800000034
Lower left sinusoidal signal (x)in) With the right-hand sinusoidal signal (x)out) Substituting the amplitude of | T | ═ xout|/|xinIf | T | ≠ 1 at this time, continuously repeating the above process, and continuously adjusting the angular frequency until | T | ═ 1, thereby realizing dynamic frequency searching;
(4) phase angle margin calculation
The cut-off frequency (omega) obtained according to the step (3)c) And a left side sinusoidal signal (xin) and a right side sinusoidal signal (x) at the corresponding angular frequencyout) Substituting the phase angle into the formula PM ═ x out(jωest)-∠xout(jωest) And obtaining the phase angle margin of the measured control loop.
Compared with the prior art, the invention has the following beneficial effects: the method for measuring the performance index of the control loop adopts the idea of dynamic frequency searching, does not need to sweep frequency like the traditional frequency response method, and has high detection speed. The performance index measuring method can measure the cut-off frequency and the phase angle margin of the control loop, and provides valuable reference information for the closed loop optimization design of the control system.
Drawings
Fig. 1 is a control loop structure diagram of an embodiment of a method for measuring a performance index of a control loop according to the present invention.
Fig. 2 is a schematic diagram of a bandwidth testing principle of the method for measuring a performance index of a control loop according to the present invention.
Fig. 3 is a schematic block diagram of extracting a detection signal according to an embodiment of the method for measuring a performance index of a control loop.
FIG. 4 is a block diagram of an embodiment of a method for measuring a performance index of a control loop according to the present inventionpAngular frequency of (omega)estIs a 400Hz left-side sinusoidal signal xinRight side sinusoidal signal xoutA waveform diagram of (a).
FIG. 5 is a block diagram of an embodiment of a method for measuring a performance indicator of a control loop according to the present inventionpAngular frequency of (omega)estIs a left-side sinusoidal signal x at 880HzinRight side sinusoidal signal xoutA waveform diagram of (a).
Detailed Description
The technical scheme of the invention is explained in detail in the following with reference to the attached drawings.
In this embodiment, the monitored control loop adopts a relatively common single-phase full-bridge inverter circuit, the filter is an LCL type filter, and the control loop is iL-Vo-igThe control mode of the three-loop control mode (the left side is an inner loop, and the right side is an outer loop) is specifically a DB-DB-PI control mode. As shown in FIG. 1, the outermost ring, i, is now testedgBandwidth of the loop (which may be considered a system of current closed loops);
the invention provides a method for measuring performance index of a control loop, which is used for measuring i in a circuit shown in figure 1gThe loop control loop bandwidth includes the following steps:
(1) injecting small signals
To the measured control loop (i)gRing) is injected with a frequency-variable sine-wave small signal xp(jωest) The input of the frequency-converted signal may be realized by a disturbing signal generator. From sine-wave small signals xp(jωest) Amplitude | x ofp(jωest) I and angular frequency omegaestObtaining the injection signal xpIs expressed as xp＝|xp(jωest)|sin(ωestt); where j is an imaginary unit. In this embodiment, the control loopInjecting an amplitude | x into the roadp(jωest) I is 1, angular frequency omegaestSine wave small signal with initial value of 400 Hz.
(2) Extracting a detection signal
Detection signal interfaces are arranged on the left side and the right side of a signal injection point of the control loop and are respectively used for detecting a detection signal x on the left side of the signal injection point in real time in(jωest) And the right side detection signal xout(jωest) (ii) a Left side detection signal xin(jωest) And the right side detection signal xout(jωest) The angular frequency omega in the detection signal at this moment is extracted by a SOGI (second-order generalized integrator)estLower left sinusoidal signal xinRight side sinusoidal signal xoutThe real part (the subscript R denotes the real part) and the imaginary part (the subscript I denotes the imaginary part) of (c). By using
Figure GDA0003577621800000051
Figure GDA0003577621800000052
Obtain the left side sinusoidal signal xinRight side sinusoidal signal xoutAmplitude and phase angle of.
(3) Dynamic frequency finding
Intersection omega of control loop open loop transfer function T and abscissacThe corresponding cut-off frequency. Due to T (j omega)est)＝-xout(jωest)/xin(jωest) I.e. at angular frequency omegaestIn the following, | T | ═ xout|/|xinL, obtaining the left side sinusoidal signal x in the step (2)inRight side sinusoidal signal xoutWhen | T | ═ 1, that is, | xout(jωest)|＝|xin(jωest) When, the current angular frequency ωestI.e. the cut-off frequency omega of the control loopc。
When | T | ≠ 1, then at the current angular frequency ωestNext, | xout(jωest) Subtract | xin(jωest) The value obtained is passed through a PI regulator (symbols in the figure)Is Gf(s), a proportional-integral regulator, the present embodiment employs: s' ═ gf (S) ═ 11660+2668000/S), resulting in the injection signal xpNew frequency of
Figure GDA0003577621800000053
Then multiplying the value by 2 pi to obtain a new angular frequency
Figure GDA0003577621800000054
New angular frequency
Figure GDA0003577621800000055
Omega is obtained through an integral link (denoted by ^ 1/s in the drawing, and a transfer function G(s) ═ 1/s) 1 estt. According to omega1 estt, will inject signal xpSin (ω) of (1)estt) is adjusted to sin (ω)1 estt), continuing to execute the process of extracting the detection signal in the step (2), and enabling the frequency to be at the new angular frequency
Figure GDA0003577621800000056
Lower left sinusoidal signal xinAnd the right side sinusoidal signal xoutSubstituting the amplitude of | T | ═ xout|/|xinIf | T | ≠ 1 at this time, continuously repeating the above process, and continuously adjusting the angular frequency until | T | ═ 1, thereby realizing dynamic frequency searching;
when | xout(jωest)|＞|xin(jωest) In case of | the injection signal x at this time is describedpAngular frequency of (omega)estGreater than the cut-off frequency omegacThe injection signal x needs to be reducedpAngular frequency of (omega)est(ii) a When | xout(jωest)|＜|xin(jωest) When l, inject signal xpAngular frequency of (omega)estLess than the cut-off frequency omegacThe injection signal x needs to be increasedpAngular frequency of (omega)est；
Continuously regulating until | xout(jωest)|＝|xin(jωest) I.e. the left-hand sinusoidal signal xinAmplitude of and right side sinusoidal signal xoutAre equal in amplitude, when the injection signal x ispAngular frequency of (omega)estI.e. the cut-off frequency omega of the control loopc. Cut-off frequency omegacI.e. the bandwidth of the control loop. A
Judging and changing the injection signal x according to the above conditionspAngular frequency of (omega)estIt can be quickly brought to the cut-off frequency omegacClose up until omegaest＝ωcTherefore, the purpose of fast frequency searching is realized. The cut-off frequency of the open-loop transfer function is very close to the bandwidth of the control loop, and the cut-off frequency is generally not distinguished in engineering application, so that the method realizes the measurement of the bandwidth of the control loop.
When x ispAngular frequency ω ofestIs a left-side sinusoidal signal x at 400HzinRight side sinusoidal signal xoutThe waveform of (2) is shown in fig. 4. As can be seen from FIG. 4, the left-hand sinusoidal signal xinIs smaller than the right-side sinusoidal signal xoutIndicating that the cutoff frequency of the loop under test is now above 400 Hz. Increasing the injection signal x continuouslypAngular frequency of (omega)estUp to the left-hand sinusoidal signal xinAmplitude of and right side sinusoidal signal xoutAre equal in magnitude. When injecting signal xpAngular frequency of (omega)estAt 880Hz, the left-side sinusoidal signal xinRight side sinusoidal signal xoutIs shown in fig. 5, at this time, the left side sinusoidal signal xinAmplitude of and right side sinusoidal signal xoutIs equal, then 880Hz is the cut-off frequency ω of the systemcI.e. the bandwidth of the control loop is 880 Hz.
(4) Phase angle margin calculation
The cut-off frequency omega obtained according to the step (3)cLeft-sided sinusoidal signal x at 880Hz and corresponding angular frequencyinRight side sinusoidal signal xoutSubstituting the phase angle into the formula PM ═ xout(jωest)-∠xout(jωest) Obtaining the phase angle margin PM of the monitored control loopestIs 42 deg..
In the control loop in the embodiment, the cutoff frequency is 900Hz and the phase angle margin is 45 degrees through theoretical calculation, the actual cutoff frequency and the phase angle margin of the control loop are lower than the actual cutoff frequency and the phase angle margin, and the theoretical value of the control loop is identical to the result obtained by the method for measuring the performance index of the control loop in the measurement result, so the measurement result is accurate within the error allowable range.
The method for measuring the performance index of the control loop only needs to inject small signals into the input reference value of the original control loop, extract the amplitude and the size of the sine wave at the corresponding frequency according to the output sampling signal in the original control loop, and can obtain the bandwidth and the phase angle margin of the control loop by adjusting the frequency of the input signals.
The invention is applicable to the prior art where nothing is said.

Claims (1)

1. A method for measuring performance indexes of a control loop is characterized by comprising the following steps:
(1) injecting small signals
Injecting a variable-frequency sine wave small signal (x) into the controlled control loopp(jωest) ); from sine-wave small signals (x)p(jωest) Amplitude (| x)p(jωest) I) and angular frequency (omega)est) The injection signal (x) can be obtainedp) Is expressed as xp＝|xp(jωest)|sin(ωestt)；
(2) Extracting a detection signal
Detection signal interfaces are arranged on the left side and the right side of a signal injection point of the control loop and are respectively used for detecting a detection signal (x) on the left side of the signal injection point in real timein(jωest) And the right side detection signal (x)out(jωest) ); left side detection signal (x)in(jωest) And the right side detection signal (x)out(jωest) Respectively extract the current angular frequency (ω) in the detection signal at that time by the SOGIest) Lower left sinusoidal signal (x)in) With the right-hand sinusoidal signal (x)out) The real and imaginary parts of (c); by using
Figure FDA0003637589950000011
Figure FDA0003637589950000012
Get the left side sinusoidal signal (x)in) With the right sinusoidal signal (x)out) The amplitude and phase angle of (d);
(3) dynamic frequency searching
Intersection (omega) of the open loop transfer function (T) of the control loop with the abscissac) Is the corresponding cut-off frequency; due to T (j omega)est)＝-xout(jωest)/xin(jωest) I.e. at angular frequency (ω)est) In the following, | T | ═ xout|/|xinL, obtaining the left side sinusoidal signal (x) in the step (2)in) With the right-hand sinusoidal signal (x)out) Is substituted into the equation, when | T | ═ 1, i.e., | xout(jωest)|＝|xin(jωest) When, the current angular frequency (ω)est) I.e. the cut-off frequency (omega) of the control loopc) (ii) a Cut-off frequency (omega)c) I.e. the bandwidth of the control loop;
when | T | ≠ 1, then at the current angular frequency (ω)est) Next, | xout(jωest) Subtract | xin(jωest) The value obtained by I passes through a PI regulator to obtain an injection signal (x)p) New frequency of
Figure FDA0003637589950000013
Then multiplying the value by 2 pi to obtain a new angular frequency
Figure FDA0003637589950000014
New angular frequency
Figure FDA0003637589950000015
Omega is obtained through an integration link1 estt; according to omega1 estt, will inject signal (x)p) Sin (ω) of (1)estt) is adjusted to sin (ω)1 estt), continuously executing the extraction detection of the step (2)Signal process and will be at the new angular frequency
Figure FDA0003637589950000021
Lower left sinusoidal signal (x)in) With the right-hand sinusoidal signal (x)out) Substituting the amplitude of | T | ═ xout|/|xinIf | T | ≠ 1 at this time, continuously repeating the above process, and continuously adjusting the angular frequency until | T | ═ 1, thereby realizing dynamic frequency searching;
(4) Phase angle margin calculation
The cut-off frequency (omega) obtained according to the step (3)c) And corresponding to the left-hand sinusoidal signal (x) at angular frequencyin) With the right-hand sinusoidal signal (x)out) Substituting the phase angle into the formula PM ═ xout(jωest)-∠xout(jωest) And obtaining the phase angle margin of the monitored control loop.
CN202110723044.7A 2021-06-25 2021-06-25 Method for measuring performance index of control loop Active CN113467418B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110723044.7A CN113467418B (en) 2021-06-25 2021-06-25 Method for measuring performance index of control loop

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110723044.7A CN113467418B (en) 2021-06-25 2021-06-25 Method for measuring performance index of control loop

Publications (2)

Publication Number Publication Date
CN113467418A CN113467418A (en) 2021-10-01
CN113467418B true CN113467418B (en) 2022-06-28

Family

ID=77873454

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110723044.7A Active CN113467418B (en) 2021-06-25 2021-06-25 Method for measuring performance index of control loop

Country Status (1)

Country Link
CN (1) CN113467418B (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103235172A (en) * 2013-04-24 2013-08-07 常熟开关制造有限公司(原常熟开关厂） Current measuring method and measuring device
CN108039910A (en) * 2017-12-26 2018-05-15 广州市仪器仪表学会 A kind of visible light communication equipment transmitting modulating performance measuring device and method
CN109406089A (en) * 2018-11-01 2019-03-01 中国空气动力研究与发展中心高速空气动力研究所 A kind of cutoff frequency gear device for fast detecting of signal conditioner
CN109946963A (en) * 2019-04-23 2019-06-28 北京航天飞腾装备技术有限责任公司 A method of judging multiloop control system nargin
CN111277325A (en) * 2020-01-20 2020-06-12 北京邮电大学 Instantaneous frequency measurement method and system with adjustable measurement range based on polarization modulator
CN111313983A (en) * 2020-02-17 2020-06-19 湖南工学院 Microwave instantaneous frequency extraction and amplification method and instantaneous frequency measurement method and system

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110085586A1 (en) * 2009-10-09 2011-04-14 John Mezzalingua Associates, Inc. Total bandwidth conditioning device
US20100123466A1 (en) * 2008-11-17 2010-05-20 Yongtao Wang System and Method for Corner Frequency Compensation
CN108206659B (en) * 2018-02-07 2020-04-07 丽水博远科技有限公司 Permanent magnet synchronous motor rotor position estimation method based on rotation high-frequency injection algorithm
CN111371362B (en) * 2020-03-17 2021-07-20 南京航空航天大学金城学院 Compensation method for rotor position estimation of permanent magnet linear motor by high-frequency injection method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103235172A (en) * 2013-04-24 2013-08-07 常熟开关制造有限公司(原常熟开关厂） Current measuring method and measuring device
CN108039910A (en) * 2017-12-26 2018-05-15 广州市仪器仪表学会 A kind of visible light communication equipment transmitting modulating performance measuring device and method
CN109406089A (en) * 2018-11-01 2019-03-01 中国空气动力研究与发展中心高速空气动力研究所 A kind of cutoff frequency gear device for fast detecting of signal conditioner
CN109946963A (en) * 2019-04-23 2019-06-28 北京航天飞腾装备技术有限责任公司 A method of judging multiloop control system nargin
CN111277325A (en) * 2020-01-20 2020-06-12 北京邮电大学 Instantaneous frequency measurement method and system with adjustable measurement range based on polarization modulator
CN111313983A (en) * 2020-02-17 2020-06-19 湖南工学院 Microwave instantaneous frequency extraction and amplification method and instantaneous frequency measurement method and system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Cascaded High Voltage Conversion Ratio Bidirectional Nonisolated DC–DC Converter With Variable Switching Frequency;Jianliang Chen et.al;《IEEE Transactions on Power Electronics》;20180220;全文 *
浅析局部放电测量仪的截止频率校准;唐翼;《计量与测试技术》;20171030;全文 *

Also Published As

Publication number Publication date
CN113467418A (en) 2021-10-01

Similar Documents

Publication Publication Date Title
Carugati et al. Variable sampling period filter PLL for distorted three-phase systems
Jovcic et al. Analytical modeling of TCSC dynamics
CN107706929B (en) Minimum variance filtering-based adaptive phase-locked loop method and system
CN110108947B (en) Impedance frequency sweep control method for disturbance mixed injection
CN109284933B (en) Electronic transformer state evaluation system and method based on mathematical statistics
CN105259414B (en) A kind of electric network impedance online test method based on inverter
CN108155643B (en) A kind of robust estimation method of the single-phase mains voltage parameter based on sliding mode observer
CN111884218B (en) Stability evaluation method and system for double-fed VSC power transmission system
CN101964655B (en) Balance error elimination type high-precision digital phase locking method
CN110768666B (en) Kalman filter-based phase-locked loop system and method for decoupling double synchronous coordinate systems
CN101261293A (en) Electric power steady-state signal tracking measurement based on self-adapting filter
CN102570428A (en) Fault location and distance protection method based on differential output of electronic mutual inductor
CN106227040A (en) Servosystem input offset method based on limiting control
Bai et al. Fully digital grid synchronization under harmonics and unbalanced conditions
CN113467418B (en) Method for measuring performance index of control loop
KR100839436B1 (en) The method of power frequency estimation using the difference between the gain and cosine and sine filter
CN104020350B (en) A kind of voltage fundamental component detection method overcoming frequency to perturb
CN106483375B (en) A kind of multi-frequency fractional harmonic wave detection method
CN106053936B (en) A kind of method and system obtaining electrical signal instantaneous frequency
CN103323708B (en) A kind of method of testing of signal source
Özdemir et al. PLL based digital adaptive filter for detecting interharmonics
CN106451571A (en) Three-phase voltage phase locking method with frequency feed-forward compensation
Wang et al. Intelligent fault diagnosis algorithm for fiber optic current transformer
CN109975720B (en) Method for simulating and testing volt-ampere characteristic of probe
CN108649590A (en) A kind of sub-synchronous oscillation analysis method and system based on complex torque coefficients

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