WO2009092848A2 - Method for monitoring the condition of the capacitors of a dc-voltage intermediate circuit - Google Patents
Method for monitoring the condition of the capacitors of a dc-voltage intermediate circuit Download PDFInfo
- Publication number
- WO2009092848A2 WO2009092848A2 PCT/FI2009/050022 FI2009050022W WO2009092848A2 WO 2009092848 A2 WO2009092848 A2 WO 2009092848A2 FI 2009050022 W FI2009050022 W FI 2009050022W WO 2009092848 A2 WO2009092848 A2 WO 2009092848A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- voltage
- intermediate circuit
- determined
- capacitance
- value
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/40—Testing power supplies
- G01R31/42—AC power supplies
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/64—Testing of capacitors
Definitions
- the object of this invention is a method for monitoring the condition of the capacitor unit of the DC-voltage intermediate circuit of a power electronics appliance, such as of a frequency converter.
- the object of the invention is also a system for monitoring the condition of the capacitor unit of the DC-voltage intermediate circuit of a power electronics appliance, such as of an inverter.
- an apparatus utilizing power electronics such as of a frequency converter
- its capacitors which are used in the DC- voltage intermediate circuit in particular for filtering noise voltages and also for storing electrical energy.
- a capacitor is at the end of its lifecycle when its capacitance has decreased by a certain relative amount.
- This invention discloses a new type of method for monitoring the condition of the capacitor pack of the intermediate circuit of a power electronics appliance provided with a frequency converter, an inverter or another direct-current intermediate circuit.
- the internal measurements that already exist in the frequency converter are utilized for monitoring the condition of the capacitor pack at the place of usage and thus the lifetime of the 1st unit of the capacitor pack is determined regularly and with the existing measurements in the DC intermediate circuit.
- the method is based on the weakening of the ability to store charge caused by ageing of the capacitance. This is verified by performing a discharge test of the voltage of the intermediate circuit.
- the method is simple, and does not require additional measurements in the system.
- the advantage achieved is measurement data obtained via regular condition monitoring of the capacitor pack, as a result of which the remaining lifetime of the power electronics appliance can be estimated. It is possible to integrate many different properties into the monitoring software of the control unit, e.g. a warning notification, which indicates that the capacitance has dropped to the critical point or to below it.
- Fig. 1a presents a prior-art frequency converter supplied from a three-phase network
- Fig. 1 b presents the equivalent switch of the intermediate circuit of a frequency converter supplied from a three-phase network
- Fig. 2 presents the theoretical discharge curve of a capacitor.
- the internal measurements of the frequency converter are utilized for monitoring the condition of the capacitor pack at the place of usage and thus the lifetime of the 1st unit of the capacitor pack is determined regularly and with the existing measurements in the DC intermediate circuit.
- Fig. 1 presents e.g. a frequency converter apparatus, which operates in four quadrants, connected to a three-phase alternating-current generator rotated by a wind rotor, with which three-phase alternating-current electricity, of which the phase voltages are U R , U s , UT, is supplied e.g. via a network filter to a three- phase alternating-current electricity network.
- the frequency converter comprises two inverter bridge units, the generator bridge 11 and the network bridge 12, the DC connections of which are connected to the direct-current intermediate circuit, which comprises a direct- current capacitor unit one and set of AC connections to the generator and a second set to the alternating-current electricity network via the network filter.
- the generator bridge 11 rectifies the three-phase alternating voltage of the generator, which comprises the phase voltages are Uu, U v , U w , into the DC voltage U D c of the DC intermediate circuit and the network bridge transforms the DC voltage of the DC intermediate circuit into three-phase alternating voltage that is suited to the alternating-current electricity network in terms of its amplitude and frequency.
- Each bridge is a six- pulse full-wave bridge, which comprises controllable semiconductor switches in each branch of the bridge, which controllable semiconductor switches are formed from e.g. the IGBTs according to Fig.
- the DC intermediate circuit comprises a capacitor unit, which comprises a number of capacitors in series and the parallel-connected capacitor packs 14- 16, of which a part belong to the brake chopper unit 15.
- the voltage of the DC intermediate circuit is measured with an internal voltage measurement 17, which is connected to the control unit 13.
- a capacitor is a component, which stores energy in an electrical field.
- the property of a capacitor to decrease oscillation of the voltage of the intermediate circuit, as well as its ability to store energy is utilized.
- capacitors are often connected in series, with which more voltage endurance is achieved, although total capacitance drops at the same time. The capacitance can be increased by connecting the capacitors in parallel to achieve the desired capacitance.
- the capacitors connected in series and in parallel and the trimmer resistors connected in parallel with them can be presented simply as a serial circuit of a capacitor and a trimmer resistor since the intermediate circuit is isolated from the network, as well as from the electrical machine, by means of breakers (Fig. 1 b).
- Fig. 1 b presents the equivalent circuit corresponding to the circuit of the capacitor pack of the DC intermediate circuit, in which Ctot is the total capacitance, Rtot the total resistance caused by the trimmer resistors and Resr is the internal resistance of the capacitors.
- DC voltages can be omitted from the equation.
- a semi-natural logarithm is also included and the equation is grouped slightly, the capacitance is solved.
- the intermediate circuit can be pre-charged with the fitted DC voltage in a standard ambient temperature, which is in practice approx. 2O 0 C.
- the pre- charging circuit 18 is removed from the intermediate circuit and how quickly the voltage of the intermediate circuit decreases is monitored with measurements.
- the application software in the control unit manages the calculation of capacitance, which further can be recorded in a separate memory in the control unit.
- the change in the relative capacitance is calculated.
- the resistance of the intermediate circuit can be omitted from the equation (4) on the assumption that the resistance will not change significantly during the lifetime of the apparatus.
- the total resistance of the intermediate circuit depends on the resistance of the IGBT transistors of the bridges as well as on the diodes that are in parallel with them, in addition to the trimmer resistors. Also the power taken by possible DC choppers connected to the intermediate circuit must be taken into account.
- the measurement requires that it be repeated always within the limits of a certain pre-determined temperature range. This is because otherwise the changing electrical properties of the components in relation to temperature would produce considerable inaccuracy in the result. With the standardization of the measuring method it is possible to achieve good accuracy and thus to obtain reliable results.
- the frequency converter When the frequency converter is in use in its final placement location a corresponding test can be repeated regularly, and in this way the condition of the capacitors of the intermediate circuit can be monitored.
- the application software analyzes the temperatures measured from the system and in this way defines a suitable time for a discharge test. The faster the change in measured voltage, the greater is the relative decrease in capacitance. When the change in capacitance compared to the value obtained in the factory instrumentation approaches the limit value given by the manufacturer, it is time to replace the capacitor pack or the whole frequency converter.
- a frequency converter may also comprise, according to the power requirement, two or more parallel generator bridges or network bridges, in which case the change in capacitance is calculated for the whole system.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Inverter Devices (AREA)
- Testing Electric Properties And Detecting Electric Faults (AREA)
- Dc-Dc Converters (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
Method and system for monitoring the condition of the capacitor arrangement (14-16) of the DC-voltage intermediate circuit of a power electronics appliance, such as of a frequency converter, at the place of usage, in which method the discharge voltage over the capacitor arrangement as a function of time is measured, and in which method the intermediate circuit is pre-charged with a pre-determined DC voltage, the pre-charging is removed from the intermediate circuit, the voltage of the intermediate circuit is measured by sampling at regular intervals, the voltage drop as a function of time is determined on the basis of the measured voltage of the intermediate circuit, the capacitance or the relative change in it is determined on the basis of the voltage drop, the value of the determined capacitance or of the relative change in it is compared to a pre-determined limit value on the basis of the voltage drop, and the necessary condition monitoring procedure is performed when the value determined with the measurement reaches the pre-determined limit value or is close to it.
Description
METHOD FOR MONITORING THE CONDITION OF THE CAPACITORS OF A DC-VOLTAGE INTERMEDIATE CIRCUIT
FIELD OF THE INVENTION
The object of this invention is a method for monitoring the condition of the capacitor unit of the DC-voltage intermediate circuit of a power electronics appliance, such as of a frequency converter.
The object of the invention is also a system for monitoring the condition of the capacitor unit of the DC-voltage intermediate circuit of a power electronics appliance, such as of an inverter.
BACKGROUND OF THE INVENTION
Generally the lifecycle of an apparatus utilizing power electronics, such as of a frequency converter, is determined by its capacitors, which are used in the DC- voltage intermediate circuit in particular for filtering noise voltages and also for storing electrical energy.
In frequency converters, large stresses are exerted on the capacitors of the DC- voltage intermediate circuit. Often unexpected destruction of a capacitor occurs, and it was not possible to anticipate its replacement. This further results in unwanted standstills in production and thus causes economic losses.
The ambient temperature, current ripple, high voltages and frequencies have a powerful impact on the lifetime of a capacitor. As a capacitor grows old its internal resistance increases, as also does the leakage current running through it, the capacitance decreases slowly over time. All these phenomena can be measured, but in practice they require opening of the appliance.
Manufacturers often define that a capacitor is at the end of its lifecycle when its capacitance has decreased by a certain relative amount.
The article E.C. Aeloiza; J-H Kim, P. Ruminot, P.N. Enjeti "A Real Time Method to Estimate Electrolytic Capacitor Condition in PWM Adjustable Speed Drives and Uninterruptible Power Supplies", pp. 2867-2872, IEEE 2005, presents a
method to estimate the state of an electrolytic capacitor in variable PWM alternating current drives and in UPS apparatuses, in which method the state can be examined at the place of usage. The method is based on the fact that the wear of a capacitor results in variations in its internal equivalent serial resistance (ESR). In the method in question, the average power of the capacitor unit, or the RMS value of the current over it, is measured. A drawback of the method is its complexity and the large requirement for the computational power of the control electronics used in the measurement.
SUMMARY OF THE INVENTION
This invention discloses a new type of method for monitoring the condition of the capacitor pack of the intermediate circuit of a power electronics appliance provided with a frequency converter, an inverter or another direct-current intermediate circuit.
In the method and the system according to the invention the internal measurements that already exist in the frequency converter are utilized for monitoring the condition of the capacitor pack at the place of usage and thus the lifetime of the 1st unit of the capacitor pack is determined regularly and with the existing measurements in the DC intermediate circuit.
The method is based on the weakening of the ability to store charge caused by ageing of the capacitance. This is verified by performing a discharge test of the voltage of the intermediate circuit.
The characteristic features of the method and of the system according to the invention are described in detail in the claims below.
The method is simple, and does not require additional measurements in the system.
The advantage achieved is measurement data obtained via regular condition monitoring of the capacitor pack, as a result of which the remaining lifetime of the power electronics appliance can be estimated. It is possible to integrate many different properties into the monitoring software of the control unit, e.g. a warning notification, which indicates that the capacitance has dropped to the critical point or to below it.
SHORT DESCRIPTION OF THE DRAWINGS
In the following, the invention will be described in more detail by the aid of an embodiment with reference to the attached drawings, wherein Fig. 1a presents a prior-art frequency converter supplied from a three-phase network, Fig. 1 b presents the equivalent switch of the intermediate circuit of a frequency converter supplied from a three-phase network, and Fig. 2 presents the theoretical discharge curve of a capacitor.
DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
In the invention the internal measurements of the frequency converter are utilized for monitoring the condition of the capacitor pack at the place of usage and thus the lifetime of the 1st unit of the capacitor pack is determined regularly and with the existing measurements in the DC intermediate circuit.
Fig. 1 presents e.g. a frequency converter apparatus, which operates in four quadrants, connected to a three-phase alternating-current generator rotated by a wind rotor, with which three-phase alternating-current electricity, of which the phase voltages are UR, Us, UT, is supplied e.g. via a network filter to a three- phase alternating-current electricity network.
The frequency converter comprises two inverter bridge units, the generator bridge 11 and the network bridge 12, the DC connections of which are connected to the direct-current intermediate circuit, which comprises a direct- current capacitor unit one and set of AC connections to the generator and a second set to the alternating-current electricity network via the network filter.
In the frequency converter presented in Fig. 1a the generator bridge 11 rectifies the three-phase alternating voltage of the generator, which comprises the phase voltages are Uu, Uv, Uw, into the DC voltage UDc of the DC intermediate circuit and the network bridge transforms the DC voltage of the DC intermediate circuit into three-phase alternating voltage that is suited to the alternating-current electricity network in terms of its amplitude and frequency. Each bridge is a six- pulse full-wave bridge, which comprises controllable semiconductor switches in each branch of the bridge, which controllable semiconductor switches are
formed from e.g. the IGBTs according to Fig. 1a (Q11 - Q16 and connected in parallel with them the diodes D11 - D16 in the bridge 11 , Q21 - Q26 and D21 - D26 in the bridge 12). The circuit allows also the passage of negative intermediate circuit current in the direction of the generator in braking situations.
It is possible to isolate the frequency converter from the network, as well as from the electrical machine, by means of the switches S1 and S2. The semiconductor switches are controlled with pulse-width modulation in the control unit 13 of the appliance.
The DC intermediate circuit comprises a capacitor unit, which comprises a number of capacitors in series and the parallel-connected capacitor packs 14- 16, of which a part belong to the brake chopper unit 15.
In the frequency converter the voltage of the DC intermediate circuit is measured with an internal voltage measurement 17, which is connected to the control unit 13.
The following presents the capacitor unit and its operation
A capacitor is a component, which stores energy in an electrical field. In the intermediate circuit of a frequency converter, the property of a capacitor to decrease oscillation of the voltage of the intermediate circuit, as well as its ability to store energy, is utilized. In the intermediate circuit, capacitors are often connected in series, with which more voltage endurance is achieved, although total capacitance drops at the same time. The capacitance can be increased by connecting the capacitors in parallel to achieve the desired capacitance.
Mathematically the capacitors connected in series and in parallel and the trimmer resistors connected in parallel with them can be presented simply as a serial circuit of a capacitor and a trimmer resistor since the intermediate circuit is isolated from the network, as well as from the electrical machine, by means of breakers (Fig. 1 b).
Fig. 1 b presents the equivalent circuit corresponding to the circuit of the capacitor pack of the DC intermediate circuit, in which Ctot is the total
capacitance, Rtot the total resistance caused by the trimmer resistors and Resr is the internal resistance of the capacitors.
According to Kirchoff s Voltage Law, we can write:
uc + uESR +uR = o
(1 ) UC + (RESR + RR )IC = O
The dependency of the current on the change in the charge in relation to time
Ic = -^- as well as the dependency of the change in the charge on the change dt in the voltage dQc = C - dUc is placed into the equation (1 )
Since UESR « UR then UESR can be omitted from the trial. After grouping, a first order differential equation is obtained:
rt The equation can be solved by making a trial function: Uc = Ae The initial value used is: Uc(0) = UDCVolmge
The solution obtained for the equation is:
-t (3) U c = UDCVoltage - e RC
Now it is possible to solve the capacitance C, when the change in voltage ( ΔU ) and the time (t) used for it are known. The frequency converter does not directly measure the voltage over the capacitor, but instead the total voltage over the intermediate circuit. The voltage loss from the effect of the internal resistance of the capacitor is insignificant compared to the inaccuracy of measurement, and therefore it can simply be assumed that c * uocvoiιage
When the voltage of the intermediate circuit drops by a certain relative amount from the time that charging of the intermediate circuit is stopped, it can be marked as Ur = v • U D1 CVoltage
The voltage of the capacitor can now be solved from the equation:
V v - U u DCVoltage - ~ I ^J DCVoltage - p e RC
DC voltages can be omitted from the equation. When a semi-natural logarithm is also included and the equation is grouped slightly, the capacitance is solved.
where "v" is the relative change in the DC voltage of the intermediate circuit, "t" is the discharge time related to it and "Rtot" is the total resistance of the trimmer resistors.
As an example, by means of the equation (3) the theoretical discharge curve of the capacitor pack can be drawn when the capacitance, the resistance of the discharge resistors, and also the DC voltage of the intermediate circuit are known (Fig. 2).
Initial values: Capacitance C=3600μF
Resistance R=10kΩ DC voltage U=1000V
Since the manufacturing tolerances of capacitors and also of trimmer resistors vary, it is worth performing a discharge test for each appliance separately. Also the changing of the capacitance as well as of the resistance in relation to temperature must be taken into account. When the apparatus is instrumented at the factory the intermediate circuit can be pre-charged with the fitted DC voltage in a standard ambient temperature, which is in practice approx. 2O0C. The pre- charging circuit 18 is removed from the intermediate circuit and how quickly the voltage of the intermediate circuit decreases is monitored with measurements. By means of this the capacitance of the intermediate circuit can be determined when the capacitors are new. The application software in the control unit
manages the calculation of capacitance, which further can be recorded in a separate memory in the control unit. Instead of the absolute value of capacitance, the change in the relative capacitance is calculated. In this case the resistance of the intermediate circuit can be omitted from the equation (4) on the assumption that the resistance will not change significantly during the lifetime of the apparatus. The total resistance of the intermediate circuit depends on the resistance of the IGBT transistors of the bridges as well as on the diodes that are in parallel with them, in addition to the trimmer resistors. Also the power taken by possible DC choppers connected to the intermediate circuit must be taken into account. The measurement requires that it be repeated always within the limits of a certain pre-determined temperature range. This is because otherwise the changing electrical properties of the components in relation to temperature would produce considerable inaccuracy in the result. With the standardization of the measuring method it is possible to achieve good accuracy and thus to obtain reliable results.
When the frequency converter is in use in its final placement location a corresponding test can be repeated regularly, and in this way the condition of the capacitors of the intermediate circuit can be monitored. The application software analyzes the temperatures measured from the system and in this way defines a suitable time for a discharge test. The faster the change in measured voltage, the greater is the relative decrease in capacitance. When the change in capacitance compared to the value obtained in the factory instrumentation approaches the limit value given by the manufacturer, it is time to replace the capacitor pack or the whole frequency converter.
It is obvious that the different embodiments of the invention are not limited solely to the example described above, but that they may be varied within the scope of the claims presented below. The invention can also be applied to other power electronics appliances provided with a direct-current intermediate circuit, such as UPS apparatuses. A frequency converter may also comprise, according to the power requirement, two or more parallel generator bridges or network bridges, in which case the change in capacitance is calculated for the whole system.
Claims
1. Method for monitoring the condition of a capacitor arrangement (14- 16) of the DC-voltage intermediate circuit of a power electronics appliance, such as of a frequency converter, at the place of usage in which method the discharge voltage over the capacitor arrangement is measured as a function of time, characterized in that in the method the intermediate circuit is pre-charged with a pre-determined DC voltage, the pre-charging is removed from the intermediate circuit, the voltage of the intermediate circuit is measured by sampling at regular intervals, the voltage drop as a function of time is determined on the basis of the measured voltage of the intermediate circuit, the capacitance or the relative change in it is determined on the basis of the voltage drop, the value of the determined capacitance or of the relative change in it is compared to a pre-determined limit value on the basis of the voltage drop, and the necessary condition monitoring procedure is performed when the value determined with the measurement reaches the pre-determined limit value or is close to it.
2. Method according to claim 1, characterized in that the voltage is measured with the internal voltage measurement of the appliance.
3. Method according to claim 1, characterized in that in the determination of the predetermined limit value of capacitance the appliance is tested such that intermediate circuit is pre-charged with the fitted DC voltage in a standard ambient temperature, the pre-charging circuit (18) is removed from the intermediate circuit and how quickly the voltage of the intermediate circuit decreases is monitored with measurements, after which the capacitance is determined in the control unit.
4. Method according to any of the preceding claims, characterized in that the capacitance is determined with the equation
-t
(4) C 'tot =
^ In v
where "v" is the relative change in the DC voltage of the intermediate circuit, "t" is the discharge time related to it and "Rtot" is the total resistance of the trimmer resistors.
5. Method according to claim 4, characterized in that the change in the relative capacitance is calculated by omitting the resistance of the intermediate circuit from the equation (4).
6. Method according to claim 3, characterized in that the pre-determined capacitance value is recorded in the memory.
7. System for monitoring the condition of a capacitor arrangement (14-
16) of the DC-voltage intermediate circuit of a power electronics appliance, such as of a frequency converter, at the place of usage, which system comprises a measuring arrangement (17), with which the voltage over the capacitor arrangement can be measured in relation to time, characterized in that the control unit (13) of the system is fitted to pre-charge the intermediate circuit with a pre-determined DC voltage, to remove the pre-charge from the intermediate circuit, to measure the voltage of the intermediate circuit at regular intervals, to determine the voltage drop on the basis of the measured voltage of the intermediate circuit, to determine capacitance or the relative change in it on the basis of the voltage drop, to compare the value of the determined capacitance or of the relative change in it to a pre-determined limit value on the basis of the voltage drop, and to control the necessary condition monitoring procedure when the value determined with the measurement reaches the limit value or is close to it.
8. System according to claim 7, characterized in that the system is fitted to measure the voltage with the internal voltage measurement of the appliance.
9. System according to claim 7, characterized in that in the determination of the pre-determined limit value of capacitance the appliance is fitted to be tested such that intermediate circuit is pre-charged with the fitted DC voltage in a standard ambient temperature, the pre-charging circuit (18) is removed from the intermediate circuit and how quickly the voltage of the intermediate circuit decreases is monitored with measurements, after which the capacitance is determined in the control unit.
10. System according to claim 9, characterized in that the calculated capacitance value is recorded in the memory that is in the control unit.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP09704219A EP2235548A2 (en) | 2008-01-21 | 2009-01-15 | Method for monitoring the condition of the capacitors of a dc-voltage intermediate circuit |
US12/863,753 US8829919B2 (en) | 2008-01-21 | 2009-01-15 | Method and system for monitoring the condition of capacitors in a DC-voltage intermediate circuit |
CN2009801025179A CN101918852A (en) | 2008-01-21 | 2009-01-15 | Method for monitoring the condition of the capacitors of a DC-voltage intermediate circuit |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI20085047 | 2008-01-21 | ||
FI20085047A FI120280B (en) | 2008-01-21 | 2008-01-21 | Method for monitoring the condition of DC capacitors |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2009092848A2 true WO2009092848A2 (en) | 2009-07-30 |
WO2009092848A3 WO2009092848A3 (en) | 2009-12-23 |
Family
ID=39004347
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FI2009/050022 WO2009092848A2 (en) | 2008-01-21 | 2009-01-15 | Method for monitoring the condition of the capacitors of a dc-voltage intermediate circuit |
Country Status (5)
Country | Link |
---|---|
US (1) | US8829919B2 (en) |
EP (1) | EP2235548A2 (en) |
CN (1) | CN101918852A (en) |
FI (1) | FI120280B (en) |
WO (1) | WO2009092848A2 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012006115A3 (en) * | 2010-06-28 | 2012-04-26 | Maxwell Technologies, Inc. | Maximizing life of capacitors in series modules |
WO2012163645A3 (en) * | 2011-05-30 | 2013-10-03 | Robert Bosch Gmbh | Method for determining current in a polyphase machine |
CN104020391A (en) * | 2014-06-13 | 2014-09-03 | 上海新时达电气股份有限公司 | Method for detecting input outage of frequency converter |
WO2014202326A1 (en) * | 2013-06-19 | 2014-12-24 | Robert Bosch Gmbh | Method for testing the working order of a dc link |
US9190860B2 (en) | 2011-11-15 | 2015-11-17 | Maxwell Technologies, Inc. | System and methods for managing a degraded state of a capacitor system |
US9882463B2 (en) | 2014-05-12 | 2018-01-30 | General Electric Technology Gmbh | In or relating to chain-link converters |
CN108614168A (en) * | 2016-12-12 | 2018-10-02 | 北京天诚同创电气有限公司 | Generating field current transformer total power test method |
EP4143594A4 (en) * | 2020-06-02 | 2024-08-07 | Kyocera Avx Components Corp | System and method for monitoring one or more characteristics of an ultracapacitor |
Families Citing this family (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8495423B2 (en) * | 2009-08-11 | 2013-07-23 | International Business Machines Corporation | Flash-based memory system with robust backup and restart features and removable modules |
JP5687484B2 (en) * | 2010-12-20 | 2015-03-18 | 矢崎総業株式会社 | Insulation state detection unit flying capacitor fault detection device |
JP5698590B2 (en) | 2011-04-14 | 2015-04-08 | 矢崎総業株式会社 | Insulation state detection unit failure detection device |
US10197607B2 (en) * | 2012-06-26 | 2019-02-05 | City University Of Hong Kong | System and method for estimating component parameters |
KR101327591B1 (en) | 2012-07-02 | 2013-11-12 | 엘에스산전 주식회사 | Apparatus for diagnosing dc link capacitor of inverter |
CN103630755B (en) * | 2013-11-27 | 2016-09-14 | 北京天诚同创电气有限公司 | Method for detecting support capacitance of direct current bus of converter |
DK2887526T3 (en) | 2013-12-19 | 2019-06-24 | Abb Schweiz Ag | Method and power rectifier for determining deterioration of a cell capacitor in a converter cell |
EP2940850A1 (en) | 2014-04-29 | 2015-11-04 | ABB Technology AG | A method for monitoring DC link capacitance in power converters |
CN104578737A (en) * | 2014-12-22 | 2015-04-29 | 浙江海得新能源有限公司 | Bus discharging circuit of wind power generation converter |
EP3257331A1 (en) | 2015-02-10 | 2017-12-20 | Philips Lighting Holding B.V. | Light device deriving condition of storage circuit |
CN105699786B (en) * | 2016-01-28 | 2018-09-04 | 重庆大学 | Dc-link capacitance monitoring method and system based on variable discharge network |
CN105717368B (en) * | 2016-01-28 | 2018-09-14 | 重庆大学 | The on-line monitoring method of three-phase system dc-link capacitance |
JP2017143647A (en) * | 2016-02-10 | 2017-08-17 | 株式会社日立製作所 | Power converter device |
JP6438453B2 (en) * | 2016-12-21 | 2018-12-12 | ファナック株式会社 | Motor drive device |
WO2019001716A1 (en) * | 2017-06-29 | 2019-01-03 | Robert Bosch Gmbh | Capacitor and capacitive sensor diagnostics checking |
EP3502722A1 (en) * | 2017-12-22 | 2019-06-26 | KONE Corporation | Method for maintenance of a frequency converter and software program realizing the same |
WO2019127185A1 (en) * | 2017-12-28 | 2019-07-04 | Abb Schweiz Ag | Method and system for on-line condition monitoring of dc-link capacitor in power converter |
EP3546959A1 (en) * | 2018-03-26 | 2019-10-02 | Siemens Aktiengesellschaft | Determination of the functionality of an electrolytic capacitor connected in a circuit arrangement |
CN112997393B (en) * | 2018-10-09 | 2022-06-14 | Abb瑞士股份有限公司 | Method and apparatus for circuit monitoring |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5804973A (en) * | 1995-06-27 | 1998-09-08 | Honda Giken Kogyo Kabushiki Kaisha | Control device in an electric vehicle |
US20050169018A1 (en) * | 2003-03-17 | 2005-08-04 | Akira Hatai | Inverter |
EP1814214A1 (en) * | 2004-10-26 | 2007-08-01 | Matsushita Electric Works, Ltd. | Discharge lamp lighting device, and lighting equipment and lighting system using the device |
JP2007318838A (en) * | 2006-05-23 | 2007-12-06 | Daikin Ind Ltd | Controller |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4331994A (en) * | 1979-09-28 | 1982-05-25 | Borg-Warner Corporation | Shootthrough fault protection system for a voltage source transistor inverter |
JPH0322821A (en) | 1989-06-19 | 1991-01-31 | Daikin Ind Ltd | Fault diagnosis unit for power source electrolytic capacitor |
FR2714233B1 (en) * | 1993-12-16 | 1996-01-12 | Telemecanique | Power control system for an asynchronous motor. |
US5471125A (en) * | 1994-09-09 | 1995-11-28 | Danfoss A/S | AC/DC unity power-factor DC power supply for operating an electric motor |
JP3173376B2 (en) | 1996-06-14 | 2001-06-04 | 株式会社日立製作所 | Apparatus for determining the capacitance of a capacitor of a three-level power converter |
JP2000222025A (en) | 1999-01-29 | 2000-08-11 | Toyo Glass Kikai Kk | Machine control board and self-diagnostic device for power converter |
US6741482B2 (en) * | 2001-09-14 | 2004-05-25 | Kabushiki Kaisha Toshiba | Power conversion device |
DE10148740B4 (en) * | 2001-09-27 | 2013-10-24 | Dr. Johannes Heidenhain Gmbh | Method for earth fault monitoring of a converter drive |
FI115322B (en) * | 2003-09-19 | 2005-04-15 | Vacon Oyj | Energy measurement with frequency converter |
FI121803B (en) * | 2005-05-03 | 2011-04-15 | Vacon Oyj | Frequency converter monitoring arrangement |
FI119493B (en) * | 2006-12-21 | 2008-11-28 | Vacon Oyj | Arrangements for measuring the current through a frequency converter |
FI121613B (en) * | 2006-12-21 | 2011-01-31 | Abb Oy | Method and system in connection with a motor fed by a voltage converter |
-
2008
- 2008-01-21 FI FI20085047A patent/FI120280B/en not_active IP Right Cessation
-
2009
- 2009-01-15 EP EP09704219A patent/EP2235548A2/en not_active Withdrawn
- 2009-01-15 CN CN2009801025179A patent/CN101918852A/en active Pending
- 2009-01-15 US US12/863,753 patent/US8829919B2/en not_active Expired - Fee Related
- 2009-01-15 WO PCT/FI2009/050022 patent/WO2009092848A2/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5804973A (en) * | 1995-06-27 | 1998-09-08 | Honda Giken Kogyo Kabushiki Kaisha | Control device in an electric vehicle |
US20050169018A1 (en) * | 2003-03-17 | 2005-08-04 | Akira Hatai | Inverter |
EP1814214A1 (en) * | 2004-10-26 | 2007-08-01 | Matsushita Electric Works, Ltd. | Discharge lamp lighting device, and lighting equipment and lighting system using the device |
JP2007318838A (en) * | 2006-05-23 | 2007-12-06 | Daikin Ind Ltd | Controller |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012006115A3 (en) * | 2010-06-28 | 2012-04-26 | Maxwell Technologies, Inc. | Maximizing life of capacitors in series modules |
US9209653B2 (en) | 2010-06-28 | 2015-12-08 | Maxwell Technologies, Inc. | Maximizing life of capacitors in series modules |
WO2012163645A3 (en) * | 2011-05-30 | 2013-10-03 | Robert Bosch Gmbh | Method for determining current in a polyphase machine |
US9285400B2 (en) | 2011-05-30 | 2016-03-15 | Robert Bosch Gmbh | Method for determining current in a polyphase machine |
DE102011076722B4 (en) * | 2011-05-30 | 2019-11-07 | Robert Bosch Gmbh | Method for current detection in a multiphase machine |
US9190860B2 (en) | 2011-11-15 | 2015-11-17 | Maxwell Technologies, Inc. | System and methods for managing a degraded state of a capacitor system |
WO2014202326A1 (en) * | 2013-06-19 | 2014-12-24 | Robert Bosch Gmbh | Method for testing the working order of a dc link |
US9882463B2 (en) | 2014-05-12 | 2018-01-30 | General Electric Technology Gmbh | In or relating to chain-link converters |
CN104020391A (en) * | 2014-06-13 | 2014-09-03 | 上海新时达电气股份有限公司 | Method for detecting input outage of frequency converter |
CN108614168A (en) * | 2016-12-12 | 2018-10-02 | 北京天诚同创电气有限公司 | Generating field current transformer total power test method |
EP4143594A4 (en) * | 2020-06-02 | 2024-08-07 | Kyocera Avx Components Corp | System and method for monitoring one or more characteristics of an ultracapacitor |
Also Published As
Publication number | Publication date |
---|---|
FI20085047A (en) | 2009-07-22 |
EP2235548A2 (en) | 2010-10-06 |
FI120280B (en) | 2009-08-31 |
FI20085047A0 (en) | 2008-01-21 |
US20100295554A1 (en) | 2010-11-25 |
CN101918852A (en) | 2010-12-15 |
US8829919B2 (en) | 2014-09-09 |
WO2009092848A3 (en) | 2009-12-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8829919B2 (en) | Method and system for monitoring the condition of capacitors in a DC-voltage intermediate circuit | |
KR101813355B1 (en) | Insulation detector and electrical device | |
KR100812760B1 (en) | Measurement Device of Internal Impedance effective value of Stationary Battery And Method Thereof | |
Pu et al. | Fault diagnosis of DC-link capacitors in three-phase AC/DC PWM converters by online estimation of equivalent series resistance | |
KR101019342B1 (en) | Online Failure Detection System of DC Output Filtering Capacitors in Power Converters | |
CN105830326B (en) | Method and power converter for determining the deterioration of the cell capaciator in converter unit | |
WO2011115797A2 (en) | Impedance balancer | |
Kulkarni et al. | Accelerated aging experiments for capacitor health monitoring and prognostics | |
CN112955758B (en) | Method for insulation resistance measurement in an inverter with a multipoint topology and inverter with a multipoint topology | |
WO2019163301A1 (en) | Management device, and electricity storage system | |
KR20190061204A (en) | System for testing sub-module of modular multilevel converter | |
CN111443298B (en) | Measuring assembly, high-voltage battery, motor vehicle and method for determining complex impedance | |
CN104734528B (en) | Polyphase electric power driver and its power cell | |
Ghadrdan et al. | On-line condition monitoring system for DC-link capacitor of back-to-back converters using large-signal transients | |
WO2020163085A1 (en) | Dc monitoring system for variable frequency drives | |
El Hayek et al. | Aging laws of electrolytic capacitors | |
Wang et al. | An SMPS-based lithium-ion battery test system for internal resistance measurement | |
Pu et al. | Online monitoring and balancing for MMC capacitor aging | |
Kamel et al. | Failure detection of the capacitor bank of the three phase diode rectifier | |
Khandebharad et al. | Electrolytic capacitor online failure detection and life prediction methodology | |
Salazar et al. | An online LiFePO 4 battery impedance estimation method for grid-tied residential energy storage systems | |
KR20180038168A (en) | System for testing capacitor | |
Paramasivam | Effects of input phase-loss and voltage unbalance on front end of passive low harmonic drive | |
JP6378585B2 (en) | Transient current measurement method, commercial power distribution system judgment method capable of measuring transient current, countermeasure method for commercial power distribution system incapable of measuring transient current, and apparatus therefor | |
Haussmann et al. | Sensorless individual cell temperature measurement by means of impedance spectroscopy using standard battery management systems of electric vehicles |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 200980102517.9 Country of ref document: CN |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2009704219 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 12863753 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 09704219 Country of ref document: EP Kind code of ref document: A2 |