An abnormality detection device includes a measuring unit 14c and a determining unit 14d. The measuring unit 14c measures, among a power supply, a capacitor, a load circuit, a switch connecting the power supply to the load circuit, and ground of a vehicle body, which are mounted on a vehicle, a first voltage of the capacitor charged by serially connecting the power supply, the capacitor, and the body ground in a state where the switch is controlled to be turned off. The determining unit 14d determines that the switch is not fixed in an ON state and an insulation resistance of the vehicle is normal when the first voltage measured by the measuring unit 14c is less than a first threshold.

A weld detection apparatus is mounted on a vehicle and measures first and second voltages of a first capacitor. The first voltage is measured when the first capacitor is charged while connected in series to a power supply and a ground of a vehicle body while switches that connect the power supply to a load circuit are controlled to be in a first state. The second voltage is measured at a predetermined timing, when the first capacitor is charged while connected in series to the power supply and the ground of the vehicle body while the switches are controlled to be in a second state different from the first state. The apparatus performs a weld detection process to decide which of the switches is welded in an ON-state when a difference between the first and second voltages is equal to or smaller than a predetermined threshold value.

Implementations of ground fault circuit interrupter (GFCI) self-test circuits may include: a current transformer coupled to a controller, a silicon controlled rectifier (SCR) test loop coupled to the controller, a ground fault test loop coupled to the controller, and a solenoid coupled to the controller. The SCR test loop may be configured to conduct an SCR self-test during a first half wave portion of a phase and the ground fault test loop may be configured to conduct a ground fault self-test during a second half wave portion of a phase. An SCR may be configured to activate the solenoid to deny power to a load upon one of the SCR self-test or the ground fault self-test being identified as failing.

A protective circuit includes a first field-effect transistor having a first drain terminal, a first source terminal and a first gate terminal, a control device by which an electrical first voltage between the first drain terminal and the first source terminal can be determined, and a first temperature sensor by which a first temperature of the first field-effect transistor can be detected, wherein a first resistance of the first field effect transistor and an electrical first current conducted via the first field-effect transistor can be determined by the control device based on the first temperature.

A switching amplifier includes a power device and a processing device. The power device is configured for powering a load and is comprised of a plurality of switches. The processing device configured to calculate a switch junction temperature for a bonding wire in each switch based at least in part on a power loss of each switch; generate a first accumulated fatigue damage of the bonding wire in each switch based on the switch junction temperature; and generate an estimated remaining lifetime of the switching amplifier based on the first accumulated fatigue damages of the bonding wires in each switch.

A method and a test device are disclosed for testing a latching magnet of a switch. The switch includes a switching contact; an electronic trip unit to monitor the current flowing and to test whether a current-dependent trip condition is met; an electrical energy store, forming a circuit with the winding of the latching magnet, the circuit being closed by the trip unit when the trip condition is met; an actuator, actuated for a first closing time by closing of the circuit and configured to separate the contact elements; and a first diode, connected in parallel with the winding and via which stored energy of the latching magnet is dissipated. The test device is configured to close the circuit for a second closing time, which is so short that no actuation of the actuator takes place. After the reopening, a test is performed to ascertain whether stored energy is dissipating.

A switch-operation-determining device provided with a determination circuit for determining whether a switch has been operated, wherein the determination circuit is provided with: a first resistor, a first diode, and a second diode serially connected in the stated order from the power-source side, such that current flows from the power source toward a ground; and a control unit for comparing the anode potential of the first diode and a threshold potential, and determining that the switch has been operated when the anode potential of the first diode is lower. Of the first diode and the second diode, it is the second diode that is connected in parallel with the switch.

A battery management system for a high-voltage battery that has a switching device with controllable switching elements for establishing and disconnecting an electrical connection between the poles of the high-voltage battery and the connection points for a consumer network, and a device for insulation monitoring. The poles and connection points are each switched to a reference potential for insulation measurement via a voltage divider. The battery management system may have a device for checking the switching status of the controllable switching elements by means of measuring devices for determining the electrical voltage. The measuring devices are arranged so that they measure the voltage between the output of the respective voltage divider and the reference potential. The device for checking the switching status of the controllable switching elements has a device for comparing the measured voltage values of the two measuring devices. A controllable switching element is switched between each of their assigned voltage dividers.

Sampling for arc-fault detection, ground-fault detection, and grounded-neutral fault detection uses a single analog-to-digital converter (ADC). The arc-fault and ground-fault sampling occurs at regular sampling periods that are relatively short com pared to the time between them, thus allowing grounded-neutral fault sampling to occur before and/or after one of these sampling periods. A predefined event may be used to ensure the grounded-neutral fault sampling occurs immediately before and/or after one of the periodic sampling periods. The predefined event may be the expiration of a timer or the time for a sinusoidal signal in a ground fault sense circuit to make a predefined number of zero-crossings. This avoids interference between the arc-fault sampling, the ground-fault sampling and grounded-neutral fault sampling, allowing a single ADC to perform all samplings concurrently. The timing of the predefined event may be periodically reset to compensate for any changes due to temperature and/or over time.

An abnormality diagnostic for a MOSFET switch element in a rechargeable battery pack for determining a short circuit abnormality (fusion) in a MOSFET switch element that causes a charge current to flow in. An on/off controller turns off a MOSFET causing a charge current to flow into a battery module, a start-of-charge instruction unit transmits to a charger an instruction signal to start a charging operation, and a short circuit abnormality diagnostic unit determines, based on a current sensor output, whether current is flowing through the MOSFET due to the charging operation to diagnose a short circuit abnormality in the MOSFET. After diagnosis of the MOSFET, a diagnosis of a short circuit abnormality in a MOSFET that causes a discharge current to flow out of the battery module is performed, and then a diagnosis of a short circuit abnormality in a charge relay is performed.