A power supply system for an electric arc furnace includes an AC input connectable to an electrical grid and an AC output for supplying at least one power electrode of the arc furnace; a resonant circuit interconnected between the AC input and the AC output. The resonant circuit includes a controllable bypass switch for connecting and disconnecting a circuit input and a circuit output of the resonant circuit and a capacitor and a main inductor connected in parallel with the bypass switch.

Provided are a charger and a control method. The charger includes: a transformer; at least one primary-side switch tube for carrying out chopping modulation on a voltage input into the transformer; a first control unit; a second control unit for generating feedback information on the basis of a voltage and/or current information output from an output end of the charger; and a first microwave unit respectively connected to the first control unit and the second control unit, and used for transmitting the feedback information to the first control unit. The first control unit is used for outputting a first control signal according to the feedback information, so as to control the turning on or the turning off of the at least one primary-side switch tube.

Provided are a charger and a control method. The charger includes: a transformer; at least one primary-side switch tube for carrying out chopping modulation on a voltage input into the transformer; a first control unit; a second control unit for generating feedback information on the basis of a voltage and/or current information output from an output end of the charger; and a first microwave unit respectively connected to the first control unit and the second control unit, and used for transmitting the feedback information to the first control unit. The first control unit is used for outputting a first control signal according to the feedback information, so as to control the turning on or the turning off of the at least one primary-side switch tube.

An energy combiner apparatus is used to convert output of a power supply, and has three output terminals, so that output ports are increased. In the three output terminals of the energy combiner apparatus, a voltage of 1500 V is output between a first output terminal and a second output terminal, a voltage of 1500 V is also output between the second output terminal and a third output terminal, and a total of 3 kV is output. Therefore, an overall output voltage is increased in a case of equal output power. Because the overall output voltage is increased, a current transmitted on a cable may be reduced. Therefore, a thinner cable may be used, so that costs of the cable are reduced. In addition, four cables conventionally required for connecting to the output terminals of the energy combiner apparatus are reduced to three, so that quantity and costs are reduced.

An energy combiner apparatus is used to convert output of a power supply, and has three output terminals, so that output ports are increased. In the three output terminals of the energy combiner apparatus, a voltage of 1500 V is output between a first output terminal and a second output terminal, a voltage of 1500 V is also output between the second output terminal and a third output terminal, and a total of 3 kV is output. Therefore, an overall output voltage is increased in a case of equal output power. Because the overall output voltage is increased, a current transmitted on a cable may be reduced. Therefore, a thinner cable may be used, so that costs of the cable are reduced. In addition, four cables conventionally required for connecting to the output terminals of the energy combiner apparatus are reduced to three, so that quantity and costs are reduced.

The present disclosure provides exemplary embodiments of voltage harvesting devices used in power distribution systems, and provides power distribution system architectures utilizing the voltage harvesting devices. Generally, the voltage harvesting devices transform distribution line AC voltages to produce a low wattage output for distribution system communication and control type devices. The voltage harvesting device can operate whether irrespective of the presence of load current.

A utility-scale energy storage and conversion system can operate two or more inverter groups such that their reactive power commands are proportional to their available reactive power range. The control system can therefore distribute the reactive power commands in proportion to the available Q range, thereby ensuring that all inverters in the utility-scale energy storage and conversion system 100 operate with the same Q “headroom”. In addition, the utility-scale energy storage and conversion system can use an on-load tap changer (LTC) to adjust a terminal voltage associated with a first group of inverters and a second group of inverters. The first group of inverters can be associated with a first rating and the second group of inverters can be associated with a second rating that is greater than the first rating.

A power harvesting system employs a saturable core transformer having two primary windings and at least one secondary winding. One of the primary windings is a high impedance winding, and the other primary winding is a low impedance winding. The two primary windings are connected with the load (motor). The secondary winding provides power to the circuit components of a replacement electronic thermostat. Relay contacts connects A/C power to either the high impedance primary winding or to the low impedance primary winding. When the relay is de-energized, A/C power is applied to the high impedance winding so that a relatively small amount of current flows through both the high impedance winding. This current is low enough that it does not energize the motor but is sufficient to generate the required voltage to transfer power to the secondary winding and is used to power the electronic thermostat. When the relay is energized, A/C power is applied directly to the low impedance primary winding, energizing the motor. At the beginning of each A/C cycle, the current through the low impedance winding builds up rapidly until the core saturates. The result is that a short pulse is generated in the secondary on both the positive and negative A/C cycle. This pulse has an amplitude determined by the turns ratio of the low impedance winding to the secondary winding and is used to power the electronic thermostat. After the core saturates, the impedance of the low impedance winding is only the resistance of the wire of the winding which is very small and results in negligible impact on the motor operation and also results in very low power dissipation.

The present disclosure is intended to provide a smaller laser oscillator that can be manufactured at a reduced cost. Provided is a laser oscillator for producing a laser beam, the laser oscillator including: a housing; a transformer arranged in the housing, connected to a power supply, and supplying power to a first device that consumes a predetermined amount of power; and a power factor correction unit arranged in the housing, having a power factor correction circuit that brings a power factor close to 1, connected to the power supply, and supplying power to a second device that consumes a relatively larger amount of power than the first device.

An embedded magnetic component transformer device includes an insulating substrate with a cavity and a magnetic core housed within the cavity. First and second electrical windings pass through the insulating substrate around the magnetic core. The first electrical winding includes a first end terminal and a second end terminal, and a first tap terminal between the first and second end terminals. The device includes circuitry with a first input terminal electrically connected to the first end terminal and a first output terminal. In a first configuration of the circuitry, the first output terminal is electrically connectable to the second end terminal. In a second configuration of the circuitry, the first output terminal is electrically connectable to the first tap terminal.