CN117129759A - DC system input impedance on-line detection device and detection method thereof, and DC system - Google Patents
DC system input impedance on-line detection device and detection method thereof, and DC system Download PDFInfo
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- CN117129759A CN117129759A CN202311197034.XA CN202311197034A CN117129759A CN 117129759 A CN117129759 A CN 117129759A CN 202311197034 A CN202311197034 A CN 202311197034A CN 117129759 A CN117129759 A CN 117129759A
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- 238000001514 detection method Methods 0.000 title claims abstract description 22
- 238000000034 method Methods 0.000 claims description 15
- 230000009466 transformation Effects 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 2
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
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- 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
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Abstract
The application relates to an on-line detection device for input impedance of a direct current system, a detection method thereof and the direct current system, comprising the following steps: the voltage square wave acquisition module is used for acquiring a voltage square wave, wherein the voltage square wave is a disturbance generated by a direct current power supply of the direct current system on the basis of constant output voltage; the current square wave acquisition module is used for acquiring a current square wave in load input current; and the load input impedance calculation module is used for calculating load input impedance according to the voltage square wave and the current square wave. The application can realize the on-line detection of the input impedance of the direct current system without stopping the load.
Description
Technical Field
The application relates to the technical field of direct current systems, in particular to an on-line detection device for input impedance of a direct current system, a detection method of the on-line detection device and the direct current system.
Background
In a dc system, since the input source and the load are not ideal, when a plurality of modules are integrated together, problems of low system reliability, poor stability or unsatisfactory dynamic performance may be caused, and in severe cases, breakdown of the entire system may be caused. In order to prevent the system from being unstable, stability judgment needs to be carried out on the direct current system, and a proper load is selected or the system is adjusted to a proper parameter.
The stability of the DC system can be judged by the ratio of the output impedance of the power supply and the input impedance of the load, and when the modulus value of the impedance ratio is less than 1, the system is stable. Therefore, to determine the stability of the system, it is necessary to know the value of the load input impedance.
The traditional method for measuring the direct current load input impedance of the cascade system mainly comprises an external voltage source disturbance method and an external current source disturbance method, wherein the two methods are used for stopping the load and only measuring the static input impedance of each load, and when a plurality of loads are used in parallel, the stability of the system is reduced due to factors such as fault states of each submodule, parameter changes, working point drift and the like.
Disclosure of Invention
The application aims to provide a method for improving the stability margin of a direct current system on line, which can realize on-line detection of the input impedance of the direct current system without stopping a load.
In order to achieve the above object, an embodiment of the present application provides an on-line detection device for input impedance of a dc system, the dc system including a dc power supply and a load, the device including:
the voltage square wave acquisition module is used for acquiring a voltage square wave, wherein the voltage square wave is a disturbance generated by a direct current power supply of the direct current system on the basis of constant output voltage;
the current square wave acquisition module is used for acquiring a current square wave in load input current;
and the load input impedance calculation module is used for calculating load input impedance according to the voltage square wave and the current square wave.
Preferably, the current square wave obtaining module is specifically configured to detect a load input current, and bias a direct current in the load input current to obtain a corresponding current square wave; the current square wave is caused by the voltage square wave.
Preferably, the load input impedance calculating module is specifically configured to perform fourier transform on the voltage square wave and the current square wave, obtain a fundamental wave of the voltage square wave and a fundamental wave of the current square wave, and calculate load input impedance according to the fundamental wave of the voltage square wave and the fundamental wave of the current square wave.
Preferably, the apparatus further comprises:
and the stability judging module is used for acquiring the output impedance of the direct current power supply and judging whether the direct current system is stable or not according to the ratio of the output impedance of the direct current power supply to the input impedance of the load.
The embodiment of the application also provides a direct current system which comprises a direct current power supply, a control loop, a load and the detection device;
the control loop is used for controlling disturbance of a voltage square wave generated by the direct current power supply on the basis of constant output voltage.
Preferably, the control loop is further configured to improve a stability margin of the dc system when the dc system is unstable.
The embodiment of the application also provides an online detection method for the input impedance of the direct current system, which is realized based on the device described in the embodiment, and comprises the following steps:
acquiring a voltage square wave, wherein the voltage square wave is a disturbance generated by a direct current power supply of the direct current system on the basis of constant output voltage;
acquiring a current square wave in load input current;
and calculating load input impedance according to the voltage square wave and the current square wave.
Preferably, the obtaining a current square wave in the load input current specifically includes:
detecting load input current, and biasing direct current in the load input current to obtain a corresponding current square wave; the current square wave is caused by the voltage square wave.
Preferably, the calculating the load input impedance according to the voltage square wave and the current square wave specifically includes:
and carrying out Fourier transformation on the voltage square wave and the current square wave respectively to obtain a fundamental wave of the voltage square wave and a fundamental wave of the current square wave, and calculating load input impedance according to the fundamental waves of the voltage square wave and the current square wave.
Preferably, the method further comprises:
and obtaining the output impedance of the direct current power supply, judging whether the direct current system is stable according to the ratio of the output impedance of the direct current power supply to the input impedance of the load, and improving the stability margin of the direct current system when the direct current system is unstable.
The embodiment of the application has the following beneficial effects:
compared with the traditional external voltage source disturbance method and external current source disturbance method, the embodiment of the application can realize detection of the input impedance of the direct current load without stopping, and further can be used for analyzing the stability of the direct current system, and when the direct current system is unstable, the input impedance and the output impedance are prevented from overlapping, so that the stability margin of the system is improved.
Details and advantages of embodiments of the application that are not described in detail in the detailed description.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required in the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of an on-line detection device for input impedance of a dc system according to an embodiment of the present application.
Fig. 2 is a schematic diagram of a dc system according to an embodiment of the application.
Fig. 3 is a flowchart of a method for detecting input impedance of a dc system in an embodiment of the application.
Detailed Description
The detailed description of the drawings is intended as an illustration of the present embodiment of the application and is not intended to represent the only form in which the present application may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the application.
An embodiment of the present application provides an apparatus for on-line detecting input impedance of a dc system, the dc system including a dc power source and a load, and referring to fig. 1, the apparatus includes:
the voltage square wave acquisition module is used for acquiring a voltage square wave, wherein the voltage square wave is a disturbance generated by a direct current power supply of the direct current system on the basis of constant output voltage;
the current square wave acquisition module is used for acquiring a current square wave in load input current;
and the load input impedance calculation module is used for calculating load input impedance according to the voltage square wave and the current square wave.
Specifically, a small voltage square wave disturbance is added to an output voltage command value of the control loop, so that the direct current power supply is added with a small voltage disturbance on the basis of outputting constant voltage; correspondingly, the detected load input current can generate a small square wave disturbance, the square wave disturbance of the input voltage and the input current for detecting the input impedance can be obtained after the direct current bias is subtracted, and then the load input impedance is calculated according to the voltage square wave and the current square wave, so that the on-line detection of the input impedance of the direct current system is realized, and the shutdown is not required.
In some embodiments, the current square wave obtaining module is specifically configured to detect a load input current, and bias a direct current in the load input current to obtain a corresponding current square wave; the current square wave is caused by the voltage square wave.
In some embodiments, the load input impedance calculating module is specifically configured to perform fourier transform on the voltage square wave and the current square wave, obtain a fundamental wave of the voltage square wave and a fundamental wave of the current square wave, and calculate the load input impedance according to the fundamental wave of the voltage square wave and the fundamental wave of the current square wave.
Specifically, fourier decomposition is performed to obtain a fundamental wave with small disturbance and each odd harmonic, and considering that higher harmonic has a large error, only the fundamental wave of voltage and current disturbance is reserved, and the input impedance of the direct current load can be obtained by ohm's law.
In some embodiments, the apparatus further comprises:
and the stability judging module is used for acquiring the output impedance of the direct current power supply and judging whether the direct current system is stable or not according to the ratio of the output impedance of the direct current power supply to the input impedance of the load.
Specifically, comparing the output impedance of the direct current power supply with the input impedance of the load, and if the output impedance of the direct current power supply is far smaller than the input impedance of the load, indicating that the direct current system is stable; conversely, if the output impedance of the dc power supply is comparable to or not significantly different from the input impedance of the load, the dc system may be unstable.
Another embodiment of the present application also provides a dc system, as shown in fig. 2, comprising a dc power Source (Source), a control loop, a Load (Load 1 ……Load n ) And the detection device described in the above embodiment;
the control loop is used for outputting a voltage command value and controlling disturbance of a voltage square wave generated by the direct current power supply on the basis of constant output voltage.
It should be noted that, by changing the frequency of the small disturbance square wave added to the voltage command value, the input impedance of the full frequency band of the direct current load can be obtained, so as to more accurately judge the stability margin of the system.
In some embodiments, the control loop is further configured to improve a stability margin of the dc system when the dc system is unstable.
Specifically, the control loop is PI control, PI parameters in the control loop are adjusted according to the measured input impedance, the input impedance of a load is improved, the output impedance of a power supply is reduced, and therefore stability of a direct current system is improved, and stable operation of the direct current system is achieved.
Another embodiment of the present application further provides an online detection method for input impedance of a dc system, implemented based on the device described in the foregoing embodiments, referring to fig. 3, where the method includes the following steps:
step S1, obtaining a voltage square wave, wherein the voltage square wave is a disturbance generated by a direct current power supply of the direct current system on the basis of constant output voltage;
s2, obtaining a current square wave in load input current;
and S3, calculating the load input impedance according to the voltage square wave and the current square wave.
In some embodiments, the step S2 specifically includes:
detecting load input current, and biasing direct current in the load input current to obtain a corresponding current square wave; the current square wave is caused by the voltage square wave.
In some embodiments, the step S3 specifically includes:
and carrying out Fourier transformation on the voltage square wave and the current square wave respectively to obtain a fundamental wave of the voltage square wave and a fundamental wave of the current square wave, and calculating load input impedance according to the fundamental waves of the voltage square wave and the current square wave.
In some embodiments, the method further comprises:
and S4, obtaining the output impedance of the direct current power supply, judging whether the direct current system is stable according to the ratio of the output impedance of the direct current power supply to the input impedance of the load, and improving the stability margin of the direct current system when the direct current system is unstable.
Specifically, the control loop is PI control, PI parameters in the control loop are adjusted according to the measured input impedance, the input impedance of a load is improved, the output impedance of a power supply is reduced, and therefore stability of a direct current system is improved, and stable operation of the direct current system is achieved.
The foregoing description of embodiments of the application has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the technical improvements in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Claims (10)
1. An on-line detection device for input impedance of a direct current system, the direct current system comprising a direct current power supply and a load, the device comprising:
the voltage square wave acquisition module is used for acquiring a voltage square wave, wherein the voltage square wave is a disturbance generated by a direct current power supply of the direct current system on the basis of constant output voltage;
the current square wave acquisition module is used for acquiring a current square wave in load input current;
and the load input impedance calculation module is used for calculating load input impedance according to the voltage square wave and the current square wave.
2. The device according to claim 1, wherein the current square wave acquisition module is specifically configured to detect a load input current, and bias a direct current in the load input current to obtain a corresponding current square wave; the current square wave is caused by the voltage square wave.
3. The device according to claim 2, wherein the load input impedance calculating module is specifically configured to fourier transform the voltage square wave and the current square wave to obtain a fundamental wave of the voltage square wave and a fundamental wave of the current square wave, and calculate the load input impedance according to the fundamental wave of the voltage square wave and the fundamental wave of the current square wave.
4. A device according to claim 3, characterized in that the device further comprises:
and the stability judging module is used for acquiring the output impedance of the direct current power supply and judging whether the direct current system is stable or not according to the ratio of the output impedance of the direct current power supply to the input impedance of the load.
5. A direct current system comprising a direct current power supply, a control loop, a load and the detection device of any one of claims 1-4;
the control loop is used for controlling disturbance of a voltage square wave generated by the direct current power supply on the basis of constant output voltage.
6. The dc system of claim 5, wherein the control loop is further configured to increase a stability margin of the dc system when the dc system is unstable.
7. An online detection method for input impedance of a direct current system, which is characterized by being implemented based on the device of any one of claims 1-4, and comprising:
acquiring a voltage square wave, wherein the voltage square wave is a disturbance generated by a direct current power supply of the direct current system on the basis of constant output voltage;
acquiring a current square wave in load input current;
and calculating load input impedance according to the voltage square wave and the current square wave.
8. The method according to claim 7, wherein the obtaining a current square wave in the load input current, in particular comprises:
detecting load input current, and biasing direct current in the load input current to obtain a corresponding current square wave; the current square wave is caused by the voltage square wave.
9. The method according to claim 8, wherein said calculating a load input impedance from said voltage square wave and said current square wave comprises:
and carrying out Fourier transformation on the voltage square wave and the current square wave respectively to obtain a fundamental wave of the voltage square wave and a fundamental wave of the current square wave, and calculating load input impedance according to the fundamental waves of the voltage square wave and the current square wave.
10. The method according to claim 9, wherein the method further comprises:
and obtaining the output impedance of the direct current power supply, judging whether the direct current system is stable according to the ratio of the output impedance of the direct current power supply to the input impedance of the load, and improving the stability margin of the direct current system when the direct current system is unstable.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311197034.XA CN117129759A (en) | 2023-09-18 | 2023-09-18 | DC system input impedance on-line detection device and detection method thereof, and DC system |
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| CN202311197034.XA CN117129759A (en) | 2023-09-18 | 2023-09-18 | DC system input impedance on-line detection device and detection method thereof, and DC system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111417859A (en) * | 2017-12-04 | 2020-07-14 | 航天喷气发动机洛克达因股份有限公司 | Load impedance tester and measuring method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111417859A (en) * | 2017-12-04 | 2020-07-14 | 航天喷气发动机洛克达因股份有限公司 | Load impedance tester and measuring method |
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