Disclosed is a method for detecting a malfunction of a voltage-limiting circuit of a control circuit, the control circuit including an output port connected to a capacitive actuator of a motor vehicle, an output voltage on the output port being, in the absence of a malfunction of the voltage-limiting circuit, equal to or lower than a theoretical maximum value. The capacitive actuator is arranged in series with a commutator, the method including steps of: placing the commutator in an open state; activating the control circuit; measuring the output voltage over the output port; and evaluating a criterion for detecting a malfunction of the voltage-limiting circuit as a function of the output voltage.

A method for determining an electrical capacitance in an intermediate circuit of an electric drive system. The electric drive system includes at least one first electrical energy source, which feeds the intermediate circuit, a drive unit, which has an inverter and an electrical load, the inverter being electrically connected on the input side with the intermediate circuit and on the output side with the electrical load, and a DC voltage converter, which is electrically connected with the intermediate circuit and measures a voltage in the intermediate circuit by high frequency sampling. The electrical capacitance in the intermediate circuit is determined from the voltage in the intermediate circuit measured by the DC voltage converter. Also described is a motor vehicle, which includes an electric drive system for implementing the method.

A driver circuit driving a plurality of capacitive loads includes: a plurality of output terminals to which the plurality of capacitive loads are to be connected; a plurality of drivers corresponding to the plurality of output terminals, each of the plurality of drivers being configured to generate a drive signal to be applied to each of the plurality of capacitive loads respectively corresponding to the plurality of drivers; and a capacitance detection circuit configured to detect a capacitance associated with each of the plurality of output terminals.

A method includes processes of (a processing part 8) calculating an estimated heat generation temperature by using drive conditions (22, a storage part 6) at least including drive timing information (18) and drive current value information (20), and temperature change characteristic information (24) of a capacitor, calculating state change information (28) of the capacitor after elapse of a reference time by using the estimated heat generation temperature, and calculating a lifespan estimation value (lifespan estimation result 30) of the capacitor by using the state change information. This enables capacitor lifespan estimation corresponding to fluctuations of a drive current value flowing through the capacitor, the applicability of the capacitor is confirmed, and the safety of equipment using the capacitor is improved.

A method of screening a lot of capacitors is provided. The method includes measuring a first leakage current of each individual capacitor in a first set of capacitors and calculating a first mean leakage current; removing each of the individual capacitors having a measured first leakage current equal to or above a first predetermined value, forming a second set of capacitors; subjecting the second set of capacitors to a burn in treatment; measuring a second leakage current for each of the individual capacitors in the second set and calculating a second mean leakage current; comparing the second leakage current for each of the individual capacitors to the first leakage current for each of the individual capacitors; and removing each of the individual capacitors having a second leakage current equal to or above a second predetermined value and/or having a second leakage current that does not change by a specified amount compared to the first leakage current for each of the individual capacitors.

The disclosure generally relates to a failure indicator for providing an indicator that a failure has occurred on a capacitor unit of a capacitor bank. In some embodiments, the failure indicator may include a magnetic element, and the failure indicator may be configured to move from a first orientation to a second orientation based on a mechanical or electromagnetic impulse in the capacitor unit resulting from a failure of the first capacitor unit. In some embodiments, the magnetic element may maintain the first failure indicator in the second orientation to indicate the failure of the first capacitor unit.

A power supply includes: a power factor correction circuit that includes a capacitor and converts an input voltage, produced by rectifying an AC input voltage, to a DC, output voltage; a current detector that detects an inflow current for the power factor correction circuit and outputs a current detection signal; an output voltage detector that detects the output voltage and outputs an output voltage detection signal; a voltage difference detector that detects a voltage difference between maximum and minimum values of a pulsation component of the output voltage detected from the output voltage detection signal; a working life determiner that compares the voltage difference and a threshold and gives notification of end of life of the capacitor when the voltage difference reaches the threshold; and a threshold updater that updates the threshold in keeping with the detected inflow current detected based on the current detection signal.

The present disclosure relates to a capacitor bank controller that automatically determines the size of a capacitor bank. For example, the capacitor bank controller may obtain voltage and current measurements while the capacitor bank is disconnected from the power line. Further, the capacitor bank controller may obtain voltage and current measurements while the capacitor bank is connected to the power line. The capacitor bank controller may determine the size of the capacitor bank based on impedances from the voltage and current measurements while the capacitor bank is connected and disconnected.

The present disclosure relates to a capacitor bank control system that uses a combination of line post sensors and wireless current sensors for control operations. For example, a capacitor bank controller may include one or more inputs that electrically couple to a line post sensor to allow the capacitor bank controller to obtain line post sensor measurements. The capacitor bank controller may include a transceiver that receives wireless current sensor measurements from first and second wireless current sensors. The capacitor bank controller may include a processor that controls one or more switching devices of a capacitor bank based at least in part on a combination of line post sensor measurements and wireless current sensor measurements.

A method for determining the remaining service life of a capacitor is disclosed, wherein the capacitor may be formed by an electrolytic capacitor. The method includes the stages of: measuring a voltage change across the capacitor during a discharging time, determining a discharging current during the discharging time, determining an actual capacitance of the capacitor on the basis of the voltage change, the discharging current and the discharging time, determining a corrected capacitance of the capacitor from the actual capacitance based on an error correction, wherein influences of the temperature on the capacitance of the capacitor are corrected during the error correction, and determining the remaining service life on the basis of a difference between the corrected capacitance and an initial capacitance of the capacitor. A system including an assessment device, configured to perform this method, and a circuit having at least one capacitor to be assessed are also disclosed.