431results about "Capacitor testing" patented technology

A method of and system for monitoring condition of a large capacitor connected across an output of a rectifier circuit in an operating electrical power transmission circuit in order to anticipate capacitor failure and facilitate appropriate corrective action is disclosed. The method includes measuring a ripple voltage on the capacitor and ripple current through the capacitor, determining from a representative signal whether the signal exceeds a predetermined threshold; and sending an output to a controller on a system operator if the signal exceeds the predetermined threshold. The ripple current and ripple voltage measurements may be provided as inputs to a digital to analog converter which produces and sends the representative signal to a microprocessor to generate the output to the controller.

A method and device for predicting defects of a capacitor, the method including determining the ripple voltage (Udc), the temperature (TP), and the current (Ic) of the capacitor, determining the value of an equivalent series resistance (ESR) of the capacitor, and the capacitance value (C) of the capacitor using a digital filter, determining information representative of the state of aging of the capacitor according to the temperature of the capacitor, and displaying that information and information representative of the value of the capacitance (C) and / or information representative of a cause associated with the state of aging according to the capacitance value. The device may include a converter and an uninterruptible power supply.

In the inverter device of the invention, when a power source connected to an electrolytic capacitor 5 is interrupted, a switching control circuit 6a controls switching elements of an inverter main circuit 7a to operate to supply a current to a load, thereby discharging charges of the electrolytic capacitor 5, and an electrolytic capacitor electrostatic capacitance calculator 10a calculates the electrostatic capacitance of the electrolytic capacitor, on the basis of: a discharged charge amount which is obtained from an outflow current Ic from the electrolytic capacitor 5, and a discharge time; and a discharge voltage ΔV which is a voltage drop from beginning of discharging of the electrolytic capacitor 5.

The present invention relates to an apparatus capable of diagnosing the aging state of a power conversion system at ordinary times and its diagnosing method to ensure the reliability of a power conversion system. The apparatus includes a current sensing means for detecting the output current of a inverter switching module or an electrolytic capacitor, and measurement and diagnosis means for extracting elements related to the aging status of the power conversion system by receiving the output current waveform of the inverter switching module and magnitude of each harmonic or an impedance voltage signal of the electrolytic capacitor. Furthermore, it is preferable that the apparatus further includes a measurement current generation means for generating measurement current to be supplied to the electrolytic capacitor. By analyzing an average value or the magnitude of harmonics by FFT analysis of the output current waveform of the inverter switching module and measuring an ESR value or a loss angle tan δ of a DC bus of the power conversion system, the present invention is able to monitor and diagnose the abnormal state attributable to the aging or degradation of the power conversion system in advance.

Systems, methods and devices which utilize Spread Spectrum Time Domain Reflectometry (SSTDR) techniques to measure degradation of electronic components are provided. Such measurements may be implemented while the components “live” or otherwise functioning within an overall system. In one embodiment, monitoring a power converter in a high power system is accomplished. In this embodiment, degradation of components within the power converter (e.g. metal-oxide-semiconductor field-effect transistors (MOSFETs), capacitors, insulated-gate bipolar transistors (IGBTs), and the like) may be monitored by processing data from reflections of an SSTDR signal to determine changes in impedance, capacitance, or any other changes that may be characteristic of components degrading. For example, an aging MOSFET may experience an increase of drain to source resistance which adds additional resistance to a current path within a power converter. Such a change is able to be analyzed monitored upon processing the reflected test signals.

A temperature of an electrolytic capacitor 24 incorporated in equipment is detected, a remaining lifetime in actual use is calculated based on a temperature-lifetime law, and the remaining lifetime is indicated. A thin film tape 23 is wound around a temperature sensor 22 for insulation, and the electrolytic capacitor 24 and the temperature sensor 22 are accommodated in a heat-shrinkable tube 25, the secondary temperature sensor 22 is brought into tight contact with the primary electrolytic capacitor 24.

A system and method for detecting input phase loss in an adjustable speed drive (ASD) includes an input unit to detect operating data from the ASD. The operating data includes a DC link current of the ASD. The system also includes a state observer that is adapted to receive the operating data from the input unit and extract a DC link capacitor current of the ASD using the DC link current. The system also includes a controller programmed to compare the extracted DC link capacitor current to a predetermined fault range and generate a fault indication of an input phase loss if the extracted DC link capacitor current is within the predefined fault range. The controller is also programmed to calculate an estimated lifespan of the DC link capacitor based on the extracted DC link capacitor current.

A level shift IC (3b) of a power supply / shutoff section (3) is operable, when a shutoff signal (Sa) is input from a timer circuit (8) for a time T during an ON state of a discharge lamp (7), to turn off a MOSFET (3a) so as to shut off power supply to a smoothing capacitor (4). When a detection signal (Sb) of a capacitor voltage is lowered to a value less than a reference voltage Vr1 during input of the shutoff signal (Sa), an output of a comparator (10) is changed from an H level to an L level in an inverted manner. In conjunction with this change, respective outputs of an auxiliary control circuit (12) and a NOT element (12a, 12b) are changed from an L level to an H level in an inverted manner. As a result, a current flows from the NOT element (12a) to an LED (13b) through a resistor (13a) to turn on the LED (13b). Thus, a life end of the smoothing capacitor 4 is annunciated, and a main control circuit (6) is operable to suppress an output of an inverter main circuit (5).

An input / output (“I / O”) system includes a plurality of input / output (“I / O”) ports, measurement circuitry, and an I / O multiplexer bus. The measurement circuitry is coupled to measure one or more electrical properties of one or more devices to be externally coupled to one or more of the I / O ports. The I / O multiplexer bus is coupled between the I / O ports and the measurement circuitry. The I / O multiplexer bus is programmable to selectively couple the measurement circuitry to any of the I / O ports.

An apparatus and method to detect failure of an electrolytic capacitor that smoothes a DC voltage in an inverter circuit. The apparatus detects failure of a smoothing electrolytic capacitor in a motor drive inverter circuit that rectifies and smoothes an AC voltage through a rectifier and the smoothing electrolytic capacitor and converts a rectified and smoothed DC voltage into a 3-phase voltage to drive a motor. The apparatus includes a voltage meter, a current sensing unit, and a controller. The voltage meter measures a DC voltage of an inverter when the motor is not in operation. The current sensing unit measures a phase current of the motor when the motor is not in operation. The controller estimates an ESR value of the smoothing electrolytic capacitor from the DC voltage of the inverter and the motor phase current to detect failure of the smoothing electrolytic capacitor.

Variable frequency motor drives and control techniques are presented in which filter capacitor faults are detected by measuring filter neutral node current and / or voltages and detecting changes in the fundamental frequency component of the measured neutral condition at the fundamental frequency of the input power and / or based on input current unbalance.

A method for predicting defects of at least one capacitor comprising:determining the ripple voltage, the temperature, and the current of the capacitor,determining the value of an equivalent series resistance of the capacitor and the capacitance value of the capacitor by means of a digital filter,determining an item of information representative of the state of ageing of the capacitor according to the temperature of the capacitor, anddisplaying said information and information representative of the value of the capacitance or / and information representative of at least one cause associated with the state of ageing according to the capacitance value.A device for predicting defects of at least one capacitor to implement the method.A converter and uninterruptible power supply comprising the device.

An apparatus for detecting a fault of a flying capacitor of an insulated condition detecting unit measures (step S1), at the start of discharge of the flying capacitor, a discharge voltage of the flying capacitor according to a charge voltage of a read capacitor. After a period from the start of discharge, the apparatus measures (step S3) a discharge voltage of the flying capacitor according to a charge voltage of the read capacitor. According to a difference between the measured discharge voltages, the apparatus obtains (step S5) a discharge amount of the flying capacitor, compares the discharge amount with a reference threshold, and diagnoses (step S7) an open fault of four capacitors that constitute the flying capacitor.

In order to detect deterioration of a DC link capacitor between a DC source and an inverter load in an electric propulsion vehicle, capacitance of the link capacitor must be accurately measured during in-service use. A charge is established on the link capacitor. The capacitor is isolated from the source and the inverter load. A constant current circuit is activated to discharge the capacitor. A first voltage is measured across the capacitor at a first time during the discharging. A second voltage is measured across the capacitor at a second time during the discharging. A discharge current flowing from the capacitor is measured during the discharging. The capacitance is calculated in response to the discharge current multiplied by a ratio of a difference between the second and first times to a difference between the first and second voltages. The calculated capacitance is monitored for a decline indicative of a failure.

Methods and associated apparatus for testing an electrochemical device, such as a fuel cell. A first method involves charging the fuel cell during a charge period; discharging the fuel cell during a discharge period; and monitoring the response of the fuel cell during at least part of the discharge period or the open-circuit response of the fuel cell. Another method involves testing the fuel cell when the fuel cell is in a passive state in which substantially no electrochemical reactions are taking place in the fuel cell. simultaneously applying a stimulus to all of the devices, and independently monitoring the response of each of the devices to the stimulus. Further methods involve obtaining test data from a device being tested; obtaining equivalent circuit values; calculating sets of simulation data for each equivalent circuit value; comparing sets of simulation data with the test data; and selecting one of the equivalent circuit values based on the comparison. This method allows all circuit parameters of each cell in a stack to be obtained from only one quick test.

A topology for surveying the integrity of a plurality of capacitors connected in series between a pair of bus lines arranged to be connected to a DC-power source comprises a plurality of resistors connected in series between the pair of bus lines, the plurality of resistors being connected in parallel to the plurality of capacitors; and a comparator comparing the electric potential of an intermediate point between two capacitors of the plurality of capacitors with the electric potential of an intermediate point between two resistors of the plurality of resistors. The comparator provides a signal signaling a difference between these two electric potentials, which indicates a loss of integrity of one capacitor of the plurality of capacitors.

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.

There is provided an apparatus for evaluating a capacitor, including: a charge / discharge control unit 100 that controls charge and discharge, a charge / discharge switch 200 that selects a connection between a capacitor CSP to be measured and a power supply unit 50 or a connection between the capacitor CSP and a discharge path DP, a discharge unit 300 that is connected to the discharge path DP and provides discharge resistance for the discharge of the capacitor CSP, a voltage measuring unit 400 that measures the voltage of the capacitor CSP, a current measuring unit 500 that measures the charge current or discharge current of the capacitor CSP, and a main control unit 600 that controls the charge and discharge through the charge / discharge control unit 100 and obtains equivalent series resistance Res, capacitance C and self discharge resistance Rsd during the charge and discharge.

Variable frequency motor drives and methods are presented in which filter capacitor faults are detected by measuring filter neutral node current and / or voltages and detecting changes in the fundamental frequency component of the measured neutral condition at the fundamental frequency of the input power and / or based on input current unbalance.

The invention relates to a capacitor detector which is characterized by comprising three sets of fixtures, three sets of feeding induction circuits, three sets of detected capacitor performance parameter measuring circuits and an automatic control device, wherein the automatic control device comprises a programmable controller, a display unit and an information input unit; the three sets of feeding induction circuits and the three sets of detected capacitor performance parameter measuring circuits are all connected with the programmable controller; the display unit is connected with the programmable controller; the programmable controller is used for receiving the practical performance parameters of the first detected capacitor, the second detected capacitor and the third detected capacitor, which are sent by the first detected capacitor, the second detected capacitor or the third detected capacitor performance parameter measuring circuit, and is used for detecting whether the above practical performance parameters are qualified or not; and the test result is displayed by the display unit. Compared with the prior art, the capacitor detector has the advantages of complete-automatization detection and high detection efficiency, and different types of capacitors can be detected according to requirements.

A method for detecting defective capacitors in a circuit and meters for that, based on passing alternative measuring current through capacitor to be tested. According to the first versions of the disclosed method, measuring signal is being applied between an envelop of the capacitor and one of its terminals to inject the measuring current inside the capacitor. That causes the current to flow through a dielectric between capacitor's plates and affect the current consumption depending on quality of the capacitor. An indicator of the meter displays one of voltage-current relationships that characterizes the capacitor. In this version the measuring current flows through a closed circuit. Another version is based on applying measuring signal to an envelop of the capacitor that inject the measuring current sequentially flowing from the meter, measuring electrode, the envelope, the capacitor's plate, the dielectric between plates, the capacitor's terminal, to a total metallic surface of all the capacitor's environment. This version uses one electrode and an open circuit. The meter displays changes in a resonance measuring signal that is a measure of the quality of the capacitor.

A method of iteratively screening a sample of electrolytic capacitors having a predetermined rated voltage is provided. The method can include measuring a first leakage current of a first set of capacitors, calculating a first mean leakage current therefrom, and removing capacitors from the first set having a first leakage current equal to or above a first predetermined value, thereby forming a second set of capacitors. The second set can be subjected to a burn in heat treatment where a test voltage can be applied, then a second leakage current of the second set of capacitors can be measured and a second mean leakage current can be calculated. Capacitors having a second leakage current equal to or above a second predetermined value can be removed from the second set, forming a third set of capacitors. Because of such iterative screening, the capacitors in the third set have low failure rates.

A power loss protection integrated circuit includes a current switch circuit (eFuse), a VIN terminal, a VOUT terminal, a buck / boost controller, and a storage capacitor terminal STR. The controller is adapted to work: 1) as a boost to take a low voltage from the VOUT terminal and to output a larger charging voltage onto the STR terminal, or 2) as a buck to take a higher voltage from the STR terminal and to buck it down to a lower voltage required on the VOUT terminal. The current switch circuit outputs a digital undervoltage signal (UV) and a digital high current signal (HC). These signals are communicated on-chip to the controller. Asserting UV causes the converter to begin operating in the buck mode. Asserting HC prevents the converter from operating in the boost mode.

A circuit protection device includes a trip mechanism and at least one capacitor configured to store electrical energy and to provide the electrical energy to the trip mechanism. The circuit protection device also includes a controller communicatively coupled to the at least one capacitor and configured to measure a charge property of the at least one capacitor, compare the measured charge property to a threshold, and output a signal indicative of the comparison.

Systems and methods according to aspects of the present invention are described. The systems and methods enable charging, soaking, and measuring of capacitors to be conducted quickly. Charging and soaking typically occurs in parallel and certain embodiments facilitate the measuring of capacitor leakage by sequentially disconnecting each capacitor and measuring the time for voltage on the capacitor to reach a predetermined threshold. Further, all capacitors can be disconnected from a charging source simultaneously and voltages can be measured for each capacitor simultaneously. Monitoring can be periodic in nature. Substantial time savings in the calculation device of leakage values and parameters can be attained.

A smoothing unit includes a first and a second smoothing capacitors, a first and a second discharge resistors connected in parallel to both ends of the first and the second smoothing capacitors, respectively. During a normal operation, both the first and the second smoothing capacitors are connected electrically to a live line. On the other hand, during a degradation diagnosis, the first and the second smoothing capacitors are alternately connected electrically to the live line at a predetermined timing, and a smoothing capacitor not electrically connected to the live line is subjected to the degradation diagnosis.

In the inverter device of the invention, when a power source connected to an electrolytic capacitor 5 is interrupted, a switching control circuit 6a controls switching elements of an inverter main circuit 7a to operate to supply a current to a load, thereby discharging charges of the electrolytic capacitor 5, and an electrolytic capacitor electrostatic capacitance calculator 10a calculates the electrostatic capacitance of the electrolytic capacitor, on the basis of: a discharged charge amount which is obtained from an outflow current Ic from the electrolytic capacitor 5, and a discharge time; and a discharge voltage ΔV which is a voltage drop from beginning of discharging of the electrolytic capacitor 5.