The invention relates to an electric circuit arrangement and a method for coupling an insulation monitoring device to an ungrounded power supply system via a coupling impedance, which is realized to be operant for each active conductor of the power supply system and which is formed as an ohmic resistance circuit, the ohmic resistance circuit having a settable resistance value which is changeable and a switching-off function for decoupling the insulation monitoring device from the network and being realized as a bidirectional cascade comprising a series circuit of two transistors provided in a mirror-inverted manner, each having a diode connected in parallel, a controlled change in resistance of the transistors for setting the changeable resistance value being effected by a control circuit and the switching-off function for decoupling from the grid being realized by setting a maximum resistance value.

A method for operating a power management device. The power management device controls a state of a plurality of electronic devices included in a system. The method includes obtaining an activation request to activate at least one electronic device from among the plurality of electronic devices. The method also includes predicting power consumption of the at least one electronic device. The method further includes determining schedule information to activate the at least one electronic device based on the predicted power consumption and current power consumption of the system.

A computing device includes a module that connects to a main board and a short detector. The short detector applies a voltage to a first electrical contact of the module; while the voltage is applied: makes a comparison of a second voltage on a second electrical contact of the module to the voltage; makes a determination, based on the comparison, that the first electrical contact is connected to the second electrical contact via a short circuit; and in response to the determination, initiates remediation of the short circuit.

A DC uninterruptible power supply apparatus with bidirectional protection function receives a DC power source and supplies power to a DC load. The DC uninterruptible power supply apparatus includes a first loop, a second loop, a third loop, and a control unit. The first loop receives the DC power source and supplies power to the DC load. The second loop converts the DC power source into an energy-storing power source to charge an energy-storing unit. The energy-storing unit provides a backup power source to the DC load through the third loop and the first loop. The control unit controls the first loop, the second loop, and the third loop to correspondingly provide a first protection mechanism, a second protection mechanism, and a third protection mechanism.

A DC uninterruptible power supply apparatus with bidirectional protection function receives a DC power source and supplies power to a DC load. The DC uninterruptible power supply apparatus includes a first loop, a second loop, a third loop, and a control unit. The first loop receives the DC power source and supplies power to the DC load. The second loop converts the DC power source into an energy-storing power source to charge an energy-storing unit. The energy-storing unit provides a backup power source to the DC load through the third loop and the first loop. The control unit controls the first loop, the second loop, and the third loop to correspondingly provide a first protection mechanism, a second protection mechanism, and a third protection mechanism.

A method for detecting an isolation fault in an isolation resistance between a positive and negative high-voltage bus rail and a vehicle chassis on a high-voltage propulsion side of a high-voltage system of an electric or hybrid-electric vehicle. The high-voltage system is split into a battery side and propulsion side by means of two high-voltage contactors located in the positive and negative high-voltage bus rails. The propulsion side includes first and second capacitors connected in series across the positive and negative bus rails, a common junction of the first and second capacitors connected to the chassis. The method supplies a low-voltage output to the positive and negative bus rails to charge the capacitors; and determines, based on charging current, voltage level or energy level of the capacitors, whether an isolation fault is present between the positive and/or negative high-voltage bus rail and the vehicle chassis on the propulsion side.

An apparatus, system and method of controlling the supply of DC current from a power source to an electrical load provides for a protective circuit that senses the characteristics of the connected load prior to permitting the enablement of a switch connecting the supply and the load. A voltage arising from applying a constant current to the load during a time period is compared with a predetermined threshold determined by the intended capacity of the switch so that, when closed, the current through the switch is compatible with the switch. The protective circuit may be used in conjunction with semiconductor switches, electromechanical contactors or relays. A plurality of such devices may be incorporated in an enclosure and controlled by logic so as to manage the supply of power from a power source to a plurality of electrical loads having differing power requirements.

In some examples, an electrical power system includes a differential bus, a power converter coupled to the differential bus, and a controller configured to control the power converter based on a first target value for the differential bus. The controller is also configured to sense that a ground fault has occurred in the electrical power system while controlling the power converter based on the first target value. The controller is further configured to, responsive to sensing that the ground fault has occurred, control the power converter based on a second target value for the differential bus, the second target value being different than the first target value.

An anti-short-circuit detection apparatus includes a probe, a detection resistor, a switching circuit, and a detection circuit. The probe is disposed between a power port and a ground port. A first terminal of the detection resistor is electrically coupled to a power circuit of the user terminal, and a second terminal of the detection resistor is electrically coupled to the probe. The switching circuit is electrically coupled to the first terminal of the detection resistor and a processor of the user terminal and is configured to perform switching to be grounded or ungrounded under the control of the processor. The detection circuit is electrically coupled to two terminals of the detection resistor and the processor, and is configured to trigger the processor to control the user terminal to issue a short-circuit warning or turn off the power circuit when the short-circuit current is not zero.

A converter apparatus includes: an AC/DC converter; a DC link capacitor connected to the converter; a voltage detection unit detecting the DC link voltage; a switching unit connecting or disconnecting between a power supply and the converter; a switching operation unit detecting an abnormality in a motor drive device including the converter apparatus and an inverter, and control the switching unit; a power supply monitoring unit detecting a voltage inputted to the converter to monitor a connection state between the power supply and the converter; a threshold value setting unit setting a threshold value to determine the presence or absence of a short circuit failure; and a short circuit failure detection unit determining that a short circuit failure has occurred, when the voltage of the DC link capacitor, immediately after the power supply is disconnected from the converter, is equal to or less than the threshold value.