CN113162042B - MPPF capacitor failure assessment method in MMC system based on band energy - Google Patents
MPPF capacitor failure assessment method in MMC system based on band energy Download PDFInfo
- Publication number
- CN113162042B CN113162042B CN202110501079.6A CN202110501079A CN113162042B CN 113162042 B CN113162042 B CN 113162042B CN 202110501079 A CN202110501079 A CN 202110501079A CN 113162042 B CN113162042 B CN 113162042B
- Authority
- CN
- China
- Prior art keywords
- capacitor
- band energy
- capacitance
- output voltage
- frequency
- 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
Links
Images
Classifications
-
- 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
-
- 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
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
-
- 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]
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Testing Electric Properties And Detecting Electric Faults (AREA)
Abstract
The invention discloses a failure evaluation method of an MPPF capacitor in an MMC system based on frequency band energy, which comprises the steps of firstly obtaining the capacitor output voltage of a capacitor to be evaluated; then, carrying out frequency domain analysis on the output voltage signal by using Fourier analysis to obtain a frequency spectrum signal; then calculating the power spectrum of the frequency domain signal; integrating the high-frequency domain section of the power spectrum of the output voltage of the capacitor to obtain the high-frequency band energy of the output voltage; calculating the capacitor failure degree D according to the high-frequency band energy; and finally, judging whether the capacitor fails according to the capacitor failure degree D. According to the method, the existing capacitance voltage signal in the MMC is used for carrying out frequency band energy analysis according to the relation that the larger the ESR value is, the larger the high-frequency band energy of the capacitance output voltage is, so that the current ESR change condition of the capacitor is obtained, the current failure state of the capacitor is further judged, the capacitor failure detection can be realized without adding an additional sensor, and the additional cost is avoided.
Description
Technical Field
The invention relates to the technical field of capacitor state monitoring, in particular to a failure evaluation method for an MPPF capacitor in an MMC system based on band energy.
Background
The renewable energy resources are generated by the aid of strategic targets of building low-carbon economy and building energy internet and the increasing demand of the economy on electric power due to rapid development. A High voltage direct current transmission (HVDC) system is widely used due to its advantages of long transmission distance, small system active power loss, etc. According to the requirements of a low-carbon intelligent power grid, the optimization design of high-capacity power electronic equipment in the future must be comprehensively considered in the aspects of cost, efficiency, reliability and the like, so that the reliability of an HVDC system becomes a problem to be solved urgently. The modularized multi-level converter valve is used as a main converter topology of the HVDC system, and the reliability research of the modularized multi-level converter valve is very important for the stable operation of the HVDC system.
Compared with a traditional two-pole voltage source type Converter, a large-capacity direct current bus capacitor usually used for energy storage and filtering is replaced by a small-sized capacitive energy storage device distributed in each sub-module in an MMC (Modular Multilevel Converter), so that the volume and the weight of the capacitor in the MMC occupy a large part of the system. MPPF (metalized polypropylene film) capacitors are widely used in MMCs because of their advantages of small size, strong ac current carrying capacity, high tolerance, etc. The aging of the MPPF capacitor can be accelerated by the fluctuation of the core temperature in the capacitor caused by high voltage stress, large current stress and alternating current working conditions in the MMC, and finally the failure of the MPPF capacitor is caused. The fault of the capacitor brings great risk to the operation of the high-voltage direct-current power transmission system, so that it is necessary to provide a failure detection method for evaluating the current health state of the MPPF capacitor.
The topological diagram of the MMC main circuit is shown in figure 1, and the point O is a zero potential reference point. The MMC comprises six bridge arms, and each bridge arm comprises N Submodules (SM) and a reactor L arm And the upper and lower bridge arms of each phase are combined into a phase unit. Each SM being a half-bridge cell, S 1 、S 2 Is an IGBT module, D 1 、D 2 Is an anti-parallel diode, C SM The direct current side capacitor of the submodule; i all right angle arm Is bridge arm current u SM For the output voltage of the submodule, i cap Charging current u for the capacitor cap The reference direction of each physical quantity is shown as the capacitance voltage. Each submodule is connected in series with the main circuit through a connecting port, and the sum of the output voltages of each submodule of the bridge arm is equal to the voltage U of the direct current bus dc . The sub-module in the MMC has three working modes, six working states, and two output states corresponding to the capacitor, as shown in fig. 2. D 1 Conducting or S 1 When the SM is switched on, the SM is in a cut-in mode, the direct current side capacitor is connected into the main circuit at the time, charging and discharging are carried out through bridge arm current, and the output voltage of the capacitor is + u cap ；S 2 Conducting or D 2 When the SM is switched on, the SM is in a cut-off mode, the direct-current side capacitor is isolated, the voltage on the two sides of the capacitor is kept unchanged, and the output voltage of the capacitor is 0; d 1 Conducting or D 2 On conduction, the SM is in blocking mode, which is an abnormal operating mode, and is typically used to pre-charge the capacitor or bypass the capacitor in the event of a system failure.
A solution similar to the present invention [ reference: sun rain Ting, state monitoring of metallized polypropylene film capacitor in MMC [ D ]. Chongqing university, 2020 ]:
considering the sub-module capacitor as impedance, the capacitance impedance can be calculated by equation (1), and the simplest and fast method for obtaining the impedance is to use fourier decomposition to represent the capacitance voltage and current response. Therefore, obtaining the impedance value at any frequency also obtains the capacitance value and the ESR.
And (3) selecting fundamental frequency and double frequency components of the capacitor voltage and the capacitor current after Fourier transform to calculate impedance, wherein the calculation formula is shown as (2).
Therefore, the steps of the scheme for realizing the capacitor state monitoring in the MMC system are as follows: and acquiring capacitor voltage and current information, carrying out Fourier change to obtain responses under fundamental frequency and double frequency, and finally calculating by a formula (1) to obtain the current capacitance value and ESR value of the capacitor.
The method in the document mainly judges the aging state of the metallized film capacitor by calculating the capacitance value of the capacitor and assists in judging the aging state by calculating the ESR value, however, the failure criterion of the metallized film capacitor is usually that the capacitance value is reduced by 5 percent, and the ESR is increased by two times.
In addition, the existing state monitoring methods for power capacitors can be basically classified into the following three types: 1. an external circuit detection method; 2. a specific signal injection method; 3. and (4) an algorithm calculation method. As shown in fig. 3.
1. Sensor detection method
And adding current and voltage information of a sensor detection capacitor into a circuit of the capacitor to be detected, and determining the current capacitance value and the ESR value by calculating the impedance, power and other information of the capacitor. Because the capacitor electrical information can be detected in real time, the method has high real-time performance and high precision. However, the MMC system has numerous sub-modules, and each sub-module contains a capacitor, so if the method is used for monitoring the health state of the capacitor, a large number of sensor detection circuits need to be added, a large amount of cost is consumed, and the economic and practical value is not high. In addition, such methods are typically calculated based on the specific operating principle of the capacitor in the circuit, and thus the portability of monitoring the capacitance state in MMC systems is poor.
2. Specific signal injection method
To avoid the high cost associated with sensor detection methods, researchers have proposed specific signal injection methods. By injecting a signal of a specific frequency into the circuit, the response of the capacitor at that frequency component is obtained, and information such as the current capacitance value and ESR value is obtained. However, the capacitor health information obtained by this method is too frequency dependent, and thus there are two problems: firstly, because capacitance detection is carried out at different frequency points, capacitance ESR information obtained by experiments cannot be compared with a simulation value; secondly, the initial value of the capacitor given by the capacitor manufacturer is obtained by performing experiments at a frequency point of 120Hz, and the capacitance values of the capacitor expressed at different frequencies are different, so that the capacitance value obtained by a specific signal injection method cannot be compared with the initial value given in the technical manual to infer the health state.
3. Calculation of a specific algorithm
Such methods are currently emerging capacitive state monitoring methods. And processing the voltage and current working conditions of the capacitor by using specific algorithms such as a least square method, a Kalman filtering method and the like, and calculating to obtain the current capacitance state information. The method does not need to increase extra cost and is easy to realize, however, various algorithms have defects of the method, so that various current state monitoring methods utilizing algorithm calculation have the defects of overlarge calculation amount, complex calculation process and the like.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a method for evaluating failure of an MPPF capacitor in an MMC system based on band energy, which reflects a change in ESR value by detecting an output voltage of the capacitor in real time and calculating a high-band energy of the capacitor voltage, and has the advantages of low cost, simple calculation, simple application, high portability, and the like. The technical scheme is as follows:
a failure evaluation method for an MPPF capacitor in an MMC system based on band energy comprises the following steps:
step 1: acquiring a capacitor output voltage of a capacitor to be evaluated;
step 2: carrying out frequency domain analysis on the capacitor output voltage signal by using Fourier analysis to obtain a frequency spectrum signal delta V (omega);
and step 3: calculating a power spectrum P (omega) of the capacitor output voltage frequency domain signal;
and 4, step 4: performing time integration on the high-frequency domain section of the power spectrum P (omega) to obtain output voltage high-frequency band energy E (w);
and 5: calculating the capacitance failure degree D:
D＝(E(w)-E 0 (w))/ΔE
wherein E is 0 (w) is the initial high band energy, Δ E is the energy added when the capacitor fails;
step 6: judging whether the capacitor fails according to the capacitor failure degree D: if the capacitor failure rate D is 1, the capacitor fails, otherwise, the capacitor is normal.
Further, the step 1 specifically includes:
establishing a capacitor equivalent model by connecting the equivalent series resistance, the equivalent series capacitance and the equivalent series inductance in series; the voltage drop on the capacitor to be measured is the sum of the voltage drops on the resistor, the capacitor and the inductor:
v(t)＝v ESR (t)+v C (t)+v L (t)
wherein v is ESR (t) is the voltage drop, v, produced by the equivalent series resistance C (t) partial voltage drop in capacitance, v L (t) is the voltage drop across the equivalent series inductance;
define the loss tangent as the ratio of ESR to capacitance impedance:
wherein, ESR is equivalent series resistance value, omega, of the capacitor to be measured 0 Taking 2 × pi × 50 as the working angular frequency; c is the capacitance value of the capacitor to be measured;
neglecting the effect of the equivalent series inductance, the capacitor output voltage is expressed as follows:
wherein, Δ v (t) is the voltage drop generated by the equivalent series resistance, and is reflected as the increment of the capacitor voltage; i.e. i arm Is the bridge arm current; theta (t-t) 0 ) Is t 0 Step signal of time, t 0 Starting time for charging the capacitor; v. of c (t 0 ) Is t 0 The capacitance at that moment partially drops.
Furthermore, in step 5, the increment of the capacitor voltage is subjected to frequency domain analysis, and a high-frequency band energy expression is obtained as follows:
wherein i ac Is the current flowing through the capacitor; omega is an angular frequency independent variable; delta is the dielectric loss angle; t is the integration time.
The invention has the beneficial effects that:
1) according to the relation that the larger the ESR value is, the larger the high-frequency band energy of the capacitor output voltage is, the frequency band energy analysis is carried out by utilizing the existing capacitor voltage signal in the MMC, the current ESR change condition of the capacitor is obtained, and then the current failure state of the capacitor is judged.
2) According to the method, the capacitor failure detection can be realized without adding an additional sensor, the additional cost is avoided, the real-time detection of the ESR value of the capacitor can be realized, the method is suitable for the health state detection of the capacitor in most switch circuits, and the universality is strong.
3) The failure detection model based on the capacitor output voltage high-frequency-band energy is established, the model can detect the capacitor output voltage high-frequency-band energy in real time, the change of the capacitor ESR value is reflected, and the relation between the high-frequency-band energy and the capacitor failure degree is qualitatively analyzed.
4) The method has simple algorithm and easy practice, and can provide a foundation for the health management of the capacitor in the large-capacity power electronic equipment.
Drawings
FIG. 1 is a topological diagram of MMC main circuit and submodule.
Fig. 2 is a diagram of six working states of the submodule.
FIG. 3 is a method of monitoring and studying the state of a metallized film capacitor.
FIG. 4 shows the capacitance voltage and the bridge arm current in the MMC system.
Fig. 5 is an equivalent circuit diagram of a capacitor.
Fig. 6 shows the output voltage waveforms of the capacitor at different ESR.
FIG. 7 is a power spectrum of the output voltage when the capacitance of the capacitor is decreased.
Fig. 8 is a power spectrum of the output voltage when the ESR of the capacitor increases.
Fig. 9 shows the capacitor voltage high band energy after ESR increase and capacitor value decrease.
Fig. 10 is a flow of capacitor online failure detection.
Detailed Description
The invention is described in further detail below with reference to the figures and specific embodiments. The current and voltage of the capacitor in the MMC system are shown in fig. 4, when the trigger signal is 1, the capacitor is charged or discharged along with the current direction of the bridge arm, the voltage is increased or decreased, when the trigger signal is 0, the capacitor is in a cut-out state, and the voltage is kept unchanged. The bridge arm current flows through the capacitor and includes a direct current component and an alternating current component, so that the capacitance voltage is also the superposition of the direct current component and the alternating current component.
An equivalent circuit diagram of the capacitor is shown in fig. 5, and in circuit analysis, it is generally considered that a capacitor equivalent model is formed by connecting an equivalent series resistance, a capacitance and an equivalent series inductance in series, and a voltage drop on the capacitance is the sum of voltage drops on the resistance, the capacitance and the inductance, which is shown in formula (3). δ is the loss angle, and the tangent of the loss angle is defined as the ratio of ESR to the capacitance impedance, as shown in (4).
v(t)＝v ESR (t)+v C (t)+v L (t) (3)
An MMC simulation platform is built in MATLAB/Simulink, and the output waveform of the capacitor after the ESR value is increased is shown in FIG. 6. The waveforms show that the capacitors are respectively connected with resistors of 0.01 Ω, 0.03 Ω and 0.05 Ω in series to simulate the output waveforms of the increased ESR, and it can be seen that the increase of the ESR does not affect the low-frequency part of the output voltage of the capacitor, but brings a large step amount at the moment of charging the capacitor, namely, high-frequency harmonics are generated compared with the output voltage of the capacitor in a healthy state. The cause of the occurrence of the step amount was analyzed as follows:
if the capacitance is at t 0 When charging is started at the moment, the current flowing through the capacitor in a short time is as follows:
wherein θ (t) is t 0 Step signal of the moment.
Neglecting the effect of the equivalent series inductance, the capacitor output voltage can be expressed as follows:
it can be seen that when the ESR increases sharply due to the capacitor failure in a healthy state, the voltage drop caused by the equivalent series resistance is not negligible. The output voltage high-frequency component is increased after the ESR value of the MPPF capacitor is increased, so that the change of the ESR value can be detected by utilizing the output voltage high-frequency component of the MPPF capacitor, and the failure detection of the MPPF capacitor is realized.
The input and the removal of the sub-modules in the MMC system are determined by the capacitance and voltage sequence of all sub-modules of the current bridge arm, so that the charging and discharging time of a capacitor is uncertain, and the difficulty is brought to the time domain analysis of the capacitance and voltage. If the frequency domain analysis is performed on the voltage by using fourier analysis, it can be known from the above description that the increase of ESR will cause a small increment to almost every frequency point of the high frequency band of the capacitor output voltage, and if this is taken as a characteristic quantity to monitor the failure state of the capacitor, it is easy to be disturbed by the environment, which results in an error in the measurement result. The present invention therefore uses the capacitive output voltage high-band energy as a characteristic quantity to perform failure detection on the capacitor. The relationship between the frequency domain representation of the signal and its band energy is shown in (7):
the frequency domain analysis is performed on the increment of the capacitor voltage through the analysis, and the band energy expression of the increment is shown as (8):
it can be seen that the rapid increase in ESR after MPPF failure results in an increase in the high frequency harmonics of the capacitor output voltage, with the high frequency energy increasing with the increase in ESR. Capacitance value reduction and ESR increase occur simultaneously in the capacitor failure process, therefore, a simulation model is established in MATLAB/Simulink to carry out high-frequency-band energy of capacitor output voltage under the conditions of capacitance value reduction and ESR increase respectively, and the output voltage power spectrum analysis results are shown in figures 7 and 8. It can be seen that when the ESR of the capacitor is increased, the output voltage power of the capacitor obviously appears layering, and the output power is increased along with the increase of the ESR; when the capacitance value is reduced, the output power is very small and is hardly influenced by the capacitance value. The output voltage power of the capacitor is integrated in the high frequency band to obtain the output voltage high frequency band energy, and the analysis result is shown in fig. 9. The voltage high band energy increases significantly with increasing ESR, while the effect on the high band energy is negligible with decreasing capacitance. Therefore, monitoring the capacitor output voltage high-frequency band energy can effectively reflect the capacitor failure state. The MPPF capacitance failure detection process is shown in fig. 10, and the specific process is as follows:
step 1: acquiring a capacitor output voltage of a capacitor to be evaluated; the expression of the capacitor output voltage is shown in formula (6).
Step 2: and performing frequency domain analysis on the capacitor output voltage signal by using Fourier analysis to obtain a frequency spectrum signal delta V (omega).
And step 3: and calculating the power spectrum P (omega) of the capacitor output voltage frequency domain signal.
And 4, step 4: performing time integration on the high-frequency domain section of the power spectrum P (omega) to obtain output voltage high-frequency band energy E (w); the output voltage high-band energy expression is shown as formula (8).
And 5: and calculating the capacitance failure degree D.
D＝(E(w)-E 0 (w))/ΔE
Wherein, E 0 (w) is the initial high band energy and Δ E is the energy added when the capacitor fails.
Step 6: judging whether the capacitor fails according to the capacitor failure degree D: if the capacitor failure rate D is 1, the capacitor fails, otherwise, the capacitor is normal.
Claims (3)
1. A failure evaluation method for an MPPF capacitor in an MMC system based on band energy is characterized by comprising the following steps:
step 1: acquiring the capacitance output voltage of an MPPF capacitor to be evaluated, wherein the MPPF capacitor is a metalized polypropylene film capacitor;
and 2, step: performing frequency domain analysis on the capacitor output voltage signal by using Fourier analysis to obtain a frequency spectrum signal delta V (omega);
and step 3: calculating a power spectrum P (omega) of the capacitor output voltage frequency domain signal;
and 4, step 4: performing time integration on the high-frequency band of the power spectrum P (omega) to obtain output voltage high-frequency band energy E (w);
and 5: calculating the capacitance failure degree D:
D＝(E(w)-E 0 (w))/ΔE
wherein E is 0 (w) is the initial high-band energy, which is the high-band energy of the capacitor in a healthy state; Δ E is the energy added when the capacitor fails;
step 6: judging whether the capacitor fails according to the capacitor failure degree D: if the capacitor failure rate D is 1, the capacitor fails, otherwise, the capacitor is normal.
2. The MPPF capacitor failure evaluation method in band energy based MMC system of claim 1, wherein step 1 specifically includes:
connecting the equivalent series resistance, the equivalent series capacitance and the equivalent series inductance in series to establish a capacitor equivalent model; the voltage drop on the capacitor to be measured is the sum of the voltage drops on the resistor, the capacitor and the inductor:
v(t)＝v ESR (t)+v C (t)+v L (t)
wherein v is ESR (t) is the voltage drop, v, produced by the equivalent series resistance C (t) partial voltage drop of capacitance, v L (t) is the voltage drop across the equivalent series inductance;
define the loss tangent as the ratio of ESR to capacitance impedance:
wherein, ESR is equivalent series resistance value, omega, of the capacitor to be measured 0 Taking 2 × pi × 50 as the working angular frequency; c is the capacitance value of the capacitor to be measured;
neglecting the effect of the equivalent series inductance, the capacitor output voltage is expressed as follows:
wherein i arm Is the bridge arm current; theta (t-t) 0 ) Is t 0 Step signal of time, t 0 Starting time for charging the capacitor; v. of c (t 0 ) Is t 0 The capacitance part of the moment drops.
3. The MPPF capacitor failure evaluation method in the MMC system based on band energy of claim 2, characterized in that, in step 4, the increment of the capacitance voltage is analyzed in frequency domain, obtaining the expression of the high-band energy as follows:
wherein i ac Is the current flowing through the capacitor; omega is an angular frequency independent variable; delta is the dielectric loss angle; t is the integration time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110501079.6A CN113162042B (en) | 2021-05-08 | 2021-05-08 | MPPF capacitor failure assessment method in MMC system based on band energy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110501079.6A CN113162042B (en) | 2021-05-08 | 2021-05-08 | MPPF capacitor failure assessment method in MMC system based on band energy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113162042A CN113162042A (en) | 2021-07-23 |
| CN113162042B true CN113162042B (en) | 2022-09-09 |
Family
ID=76873995
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110501079.6A Active CN113162042B (en) | 2021-05-08 | 2021-05-08 | MPPF capacitor failure assessment method in MMC system based on band energy |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113162042B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105915049A (en) * | 2016-04-06 | 2016-08-31 | 南京理工大学 | Device and method for monitoring ESR (Equivalent Series Resistance) and C (Capacitance) of output capacitor in DCM boost converter |
| CN110261698A (en) * | 2019-06-20 | 2019-09-20 | 重庆大学 | Metallization film capacitor reliability assessment method based on MMC converter valve application operating condition |
| CN111190057A (en) * | 2020-01-21 | 2020-05-22 | 同济大学 | Method and system for monitoring ESR (equivalent series resistance) of direct current capacitor on line |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107888098B (en) * | 2017-12-07 | 2019-08-06 | 国网山东省电力公司电力科学研究院 | A kind of high-voltage large-capacity flexible HVDC transmission system Multipurpose Optimal Method |
| CN110912432A (en) * | 2018-09-17 | 2020-03-24 | 长沙理工大学 | MMC capacitor voltage-sharing strategy with lower switching frequency and complexity |
| CN110850213B (en) * | 2019-11-26 | 2021-09-28 | 中国铁路上海局集团有限公司 | EMC (electro magnetic compatibility) life evaluation method of filter capacitor |
| CN111525561B (en) * | 2020-05-14 | 2022-06-17 | 上海交通大学 | Method for evaluating stability of modular multilevel converter under multi-frequency cross coupling |
| CN111665393B (en) * | 2020-05-15 | 2021-07-13 | 上海交通大学 | MMC submodule capacitor capacitance value and ESR value online monitoring method and device |
-
2021
- 2021-05-08 CN CN202110501079.6A patent/CN113162042B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105915049A (en) * | 2016-04-06 | 2016-08-31 | 南京理工大学 | Device and method for monitoring ESR (Equivalent Series Resistance) and C (Capacitance) of output capacitor in DCM boost converter |
| CN110261698A (en) * | 2019-06-20 | 2019-09-20 | 重庆大学 | Metallization film capacitor reliability assessment method based on MMC converter valve application operating condition |
| CN111190057A (en) * | 2020-01-21 | 2020-05-22 | 同济大学 | Method and system for monitoring ESR (equivalent series resistance) of direct current capacitor on line |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113162042A (en) | 2021-07-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105548792B (en) | Matrix converter switch open method for diagnosing faults based on PREDICTIVE CONTROL | |
| US20140114592A1 (en) | Operational monitoring of electrochemical capacitors | |
| CN102495292B (en) | Method and circuit for online monitoring capacity state of bus capacitor | |
| CN109921614B (en) | Sequencing-based modular multilevel converter capacitor state monitoring method | |
| CN113311239B (en) | Electric automobile insulation resistance detection circuit and method | |
| CN101918852A (en) | Method for monitoring the condition of the capacitors of a DC-voltage intermediate circuit | |
| CN109459618A (en) | The online capacitance detection method of the standard of electric drive system for electric vehicles dc-link capacitance | |
| Ghadrdan et al. | Condition monitoring of dc-link electrolytic capacitor in back-to-back converters based on dissipation factor | |
| CN110275114A (en) | Accumulator internal resistance on-line monitoring method based on combined filter algorithm | |
| CN110687471A (en) | Direct current power supply aging monitoring system | |
| CN110208649A (en) | Commutation fault detection method and device based on alternating voltage decrease speed | |
| CN113162042B (en) | MPPF capacitor failure assessment method in MMC system based on band energy | |
| CN104836462A (en) | Detection method of frequency and phase of input alternating current of air conditioning system and device | |
| CN112083232A (en) | Capacitance value monitoring method for capacitor of modular multilevel converter | |
| Wang et al. | LPV Model-Based Fault Detection and Isolation in DC Microgrids Through Signature Recognition | |
| KR101171557B1 (en) | A Simple ESR Measurement System for DC Bus Capacitor Using DC/DC Converter | |
| CN115060992B (en) | MMC submodule capacitor aging detection method | |
| Eroğlu et al. | Design and implementation of an ultracapacitor test system | |
| Hossain et al. | Battery Impedance Measurement Using Electrochemical Impedance Spectroscopy Board | |
| CN212540565U (en) | Frequency converter electrolytic capacitor test meter | |
| CN111769595B (en) | Wind driven generator network side converter equivalent capacitance solving method based on parameter identification | |
| Cheng et al. | Modified kalman filtering method to reduce the error of power grid impedance online estimation | |
| Yang | Peukert's Law for Supercapacitor Parallel and Series Modules With Constant Power Loads | |
| Qiu et al. | Research on capacitance voltage balance of modular multilevel converter based on improved quick sorting method | |
| CN117872138B (en) | Battery detection circuit and electronic equipment |
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 |