A utility meter includes: a rectifier configured to rectify AC voltage from a power grid to generate a primary DC voltage supply; and a primary holdup circuitry, including: first capacitors coupled to a primary DC voltage rail and configured to store energy from the primary voltage supply; a switch coupled to the first capacitors; and a control circuit configured to control the primary holdup circuitry, wherein the control circuit is configured to: determine that a secondary DC voltage of a secondary voltage supply is approximately equal to a first specified threshold voltage; and generate a control signal to causes the switch to turn on and cause the one or more first capacitors to release a portion of the energy stored in the one or more first capacitors to the primary DC voltage rail.

An electronic device comprising: a power supply apparatus including a first converter configured to generate driving power and a second converter configured to generate first standby voltage and second standby voltage; and a main body operated based on the driving power and the second standby power received from the power supply apparatus. The second converter is configured to: during a normal mode operation and a standby mode operation, obtain the first standby voltage and adjust the first standby power based on the obtained standby power; and during the standby mode operation, obtain the second standby voltage; and in response to the obtained second standby voltage being equal to or less than a reference level, perform the normal mode operation to control the first standby voltage to be maintained at a first voltage level and control the second standby voltage to be maintained at a second voltage level.

An UPS device for electric power distribution installations, the UPS device including: first electric terminals for electrical connection with an electric load to be fed by the UPS device; second electric terminals for electrical connection with a power supply source adapted to feed the UPS device; third electric terminals for electrical connection with a back-up unit adapted to feed the UPS device, when the power supply source is not available, the back-up unit having one or more replaceable batteries; a power conversion stage electrically connectable with the first, second and third electric terminals, the power conversion stage being adapted to receive a power supply voltage from the power supply source or a back-up voltage from the back-up unit, when the power supply source is not available, and being adapted to provide an adjustable load voltage to the electric load; and an interface stage to electrically couple or decouple the back-up unit with or from the power conversion stage. The interface stage includes a feeding circuit to temporary feed the controller during a transient time interval following a replacement of the batteries of the back-unit.

A system is described that turns off a high power, power supply when a device no longer needs high power. A low power, power supply or a rechargeable battery provides power to determine when the device again needs high power. The low power supply consumes a minimum possible power when the device does not need high power and the power rechargeable battery is not charged. That is, the high power and low power, power supplies are turned on or off based on the real time power consumption need of the device and the charged state of the battery. The power need of the device is monitored by a current shunt monitoring circuit and a control signal monitoring circuit.

Embodiments of systems and methods disclosed provide a hydraulic fracturing unit that includes a reciprocating plunger pump configured to pump a fracturing fluid and a powertrain configured to power the reciprocating plunger pump. The powertrain includes a prime mover and a drivetrain, the prime mover including a gas turbine engine. The hydraulic fracturing unit also includes auxiliary equipment configured to support operation of the hydraulic fracturing unit including the reciprocating plunger pump and the powertrain. A power system is configured to power the auxiliary equipment. The power system includes a power source and a power network. The power source is configured to generate power for the auxiliary equipment. The power network is coupled to the power source and the auxiliary equipment, and configured to deliver the power generated by the power source to the auxiliary equipment. Associated systems including a plurality of hydraulic fracturing units are also provided.

Embodiments of systems and methods disclosed provide a hydraulic fracturing unit that includes a reciprocating plunger pump configured to pump a fracturing fluid and a powertrain configured to power the reciprocating plunger pump. The powertrain includes a prime mover and a drivetrain, the prime mover including a gas turbine engine. The hydraulic fracturing unit also includes auxiliary equipment configured to support operation of the hydraulic fracturing unit including the reciprocating plunger pump and the powertrain. A power system is configured to power the auxiliary equipment. The power system includes a power source and a power network. The power source is configured to generate power for the auxiliary equipment. The power network is coupled to the power source and the auxiliary equipment, and configured to deliver the power generated by the power source to the auxiliary equipment. Associated systems including a plurality of hydraulic fracturing units are also provided.

A system (e.g., a monitoring device) for monitoring a first battery (e.g., a vehicle battery) provided in a vehicle is provided with a monitoring unit for monitoring the electric state of the first battery (e.g., the vehicle battery) capable of starting a motor of the vehicle; and a power supply unit that is a second battery for supplying electric power to the monitoring unit. The monitoring unit may determine whether or not the motor is stopped, and when the motor is stopped, the monitoring unit may monitor, as the electric state of the first battery, e.g., the voltage of the first battery.

A system (e.g., a monitoring device) for monitoring a first battery (e.g., a vehicle battery) provided in a vehicle is provided with a monitoring unit for monitoring the electric state of the first battery (e.g., the vehicle battery) capable of starting a motor of the vehicle; and a power supply unit that is a second battery for supplying electric power to the monitoring unit. The monitoring unit may determine whether or not the motor is stopped, and when the motor is stopped, the monitoring unit may monitor, as the electric state of the first battery, e.g., the voltage of the first battery.

A diode is provided in a first supply route for the electric power from an AC adaptor, rectifies the current from the AC adaptor and, at the output side thereof, is connected to a second supply route for the electric power from an AC adaptor. A detecting unit is connected to the input side of the diode in the first supply route and, based on the voltage that is input from the first supply route, detects whether the AC adaptor is connected. A resistance control unit reduces the combined resistance between the ground and the input side of the diode when the temperature of the device, including the diode, is equal to or more than a predetermined temperature.

A power supply charging system having first and second alternating power cells, a motor driven generator adapted to operably switch between providing power between the first and second alternating power cells, a third power cell which supplies power to the motor driven generator, and a control system having a power cell managing module and a charge control module. The power cell module is adapted to alternate the motor driven generator to operably switch between providing power to the first and second alternating power cells. The charge control module is adapted to detect the occurrence of a pre-determined power supply condition to activate the motor driven generator to provide power to the first or second alternating power cells. The power supply charging system may find particular use in generating a direct current, converting the direct current to an alternating current, and providing a continuous alternating current to a facility or equipment.