A method and system are provided for transferring a load between a primary power source and a secondary power source. In accordance with the disclosure, a controller senses, via a sensor, an electrical signal providing power from the primary power source to the load. The controller also detects a non-conforming power event by determining that a parameter of the electrical signal is either more or less than a first threshold value. Responsive to the detection of the non-conforming power event, the controller determines a quantity of non-conforming power events that occur during a first time interval. The controller further can compares the determined quantity of non-conforming power events to a second threshold value. Responsive to the determined quantity of non-conforming power events being either greater or lesser than the second threshold value, the controller initiates a control signal, such as a control signal to initiate a load transfer.

One example includes a relay device that is comprised of a galvanic isolation barrier, a protection control and power extractor, and an electronic switch. The galvanic isolation barrier is coupled to an input of the relay device and receives a switch control signal and outputs another switch control signal. The protection control and power extractor is coupled to an output of the galvanic isolation barrier. The protection control and power extractor extracts power from a power supply coupled to the relay device. The protection control and power extractor is responsive to the other switch control signal and generates a protection signal in response to a determination of an operating parameter of the relay device. The protection control and power extractor further outputs an electronic switch device signal based on the generated protection signal.

A vehicle includes charger contactors configured to selectively electrically couple terminals for connecting to a charger to corresponding terminals of a high-voltage bus. The vehicle includes a precharge contactor configured to selectively couple a terminal of a battery to the high-voltage bus through an impedance element. The vehicle includes a controller programmed to command the charger contactors to an open state for a drive cycle and command the precharge contactor to close at a start of the drive cycle and, responsive to a voltage across the terminals for connecting to the charger changing from being less than a first predetermined voltage immediately prior to the precharge contactor being closed to being greater than a second predetermined voltage at a completion of precharging, inhibit vehicle operation and disconnect the battery from the high-voltage bus.

A circuit includes a voltage detection path having a first transistor and a second transistor coupled to the first voltage detection path by a first terminal of the second transistor. The first voltage detection path includes: a first current source and a first voltage divider unit coupled to the first current source. The first transistor is coupled to the first voltage divider unit by a first terminal of the first transistor. A first voltage value at a second terminal of the first transistor is configured to switch between a first high voltage value and a first low voltage value at least partially based on a first detection voltage value provided at the first terminal of the first transistor by the first voltage divider unit. A second voltage at a second terminal of the second transistor is configured to switch between a second high voltage value and a second low voltage value at least partially based on the first voltage value at the second terminal of the first transistor.

A protection circuit including an auxiliary winding, a rectifier unit, the filter unit, a voltage divider unit and a controller is provided. The auxiliary winding is configured to induce an AC voltage. The rectifier unit is coupled to the auxiliary winding and configured to rectify the AC voltage into a DC voltage. The filter unit is coupled to the rectifier unit and configured to filter the DC voltage into a DC filter voltage. The voltage divider unit is coupled to the rectifier unit and the filter unit to transmit the DC filter voltage. The controller is coupled to the voltage divider unit and configured to detect a partial voltage of the DC filter voltage and detect whether to activate a protection mechanism according to the partial voltage.

A method for characterizing power quality events in an electrical system includes deriving electrical measurement data for at least one first virtual meter in an electrical system from (a) electrical measurement data from or derived from energy-related signals captured by at least one first IED in the electrical system, and (b) electrical measurement data from or derived from energy-related signals captured by at least one second IED in the electrical system. In embodiments, the at least one first IED is installed at a first metering point in the electrical system, the at least one second IED is installed at a second metering point in the electrical system, and the at least one first virtual meter is derived or located at a third metering point in the electrical system. The derived electrical measurement data may be used to generate or update a dynamic tolerance curve associated with the third metering point.

A method of generating a gate drive signal for driving a control terminal of a power switch includes detecting a system input signal; determining a signal pulse of the system input signal being a first signal pulse following a power up event, or following an idle period, or following removal of a fault condition; and in response, generating a soft gate drive signal to drive the control terminal of the power switch to softly turn on the power switch. In another embodiment, the method includes determining a duration of the on period of the system input signal exceeding a maximum on duration and in response, disabling the gate drive signal to turn off the power switch; and determining a deassertion transition of the system input signal and in response, blocking the system input signal from the gate drive signal for a minimum off duration.

An abnormal-voltage protection apparatus includes a switch unit, a voltage detection unit, and a delay time control unit. The switch unit is coupled to a power supplying path formed between an AC power source and a load. The voltage detection unit detects the AC power source and provides a detection signal. The delay time control unit is coupled to the voltage detection unit and the switch unit, and receives the detection signal and provides a control signal to the switch unit according to the detection signal. When the voltage detection unit detects that the AC power source changes from an abnormal voltage to a normal voltage, the delay time control unit turns on the switch unit by the control signal after a delay time so that the AC power source supplies power to the load through the power supplying path.

A Micro Electro-Mechanical System (MEMS) device comprises an evaluator circuit that receives a temperature signal, where the evaluator circuit compares the received temperature signal to a lower threshold value and an upper threshold value, and where the evaluator circuit generates an evaluation signal indicating when the temperature signal is between the lower threshold value and the upper threshold value; and a loading circuit that receives the evaluation signal, where the loading circuit generates a first pre-set output signal indicating when the temperature signal is between the lower threshold value and the upper threshold value, and wherein the loading circuit generates a second pre-set output signal when the temperature signal is not between the lower threshold value and the upper threshold value, such that the MEMS device functions as a 2-wire electronic sense circuit providing both an indication state and deriving power from an external two-wire sense circuit.

An LED driver includes a voltage detector and a controller. The voltage detector is configured to couple to an LED string comprising a plurality of series-coupled LEDs and to detect a voltage across the LED string to generate a feedback signal. The controller is configured to control an amount of current provided to the LED string in response to the feedback signal, with an amount of power provided to the LED string being substantially constant. The voltage detector can be coupled in parallel with the LED string, and may be a resistor divider. The controller is further configured to couple to a DC-DC converter comprising a switch controlled by the controller and configured to generate an output current and an output voltage coupled to the LED string to provide the amount of power to the LED string.