A power transforming apparatus for supplying power to a motor having a magnetic bearing includes: a converter configured to, in an initial operation, receive AC power, and an auxiliary circuit performing initial charging by rectifying the AC power to a second power and supplying the rectified second power to an inverter controller and a magnetic bearing controller. The inverter controller outputs a signal to an inverter using the second power and controls the inverter to supply a rectified DC voltage to the converter, and the converter is configured to, during a normal operation, stop supplying the second power to the inverter controller and control the rectified DC voltage to be supplied to the inverter controller and the magnetic bearing controller, and, based on a power failure being detected, outputs a control signal such that the second power is supplied to the inverter controller and the magnetic bearing controller.

A power transforming apparatus for supplying power to a motor having a magnetic bearing includes: a converter configured to, in an initial operation, receive AC power, and an auxiliary circuit performing initial charging by rectifying the AC power to a second power and supplying the rectified second power to an inverter controller and a magnetic bearing controller. The inverter controller outputs a signal to an inverter using the second power and controls the inverter to supply a rectified DC voltage to the converter, and the converter is configured to, during a normal operation, stop supplying the second power to the inverter controller and control the rectified DC voltage to be supplied to the inverter controller and the magnetic bearing controller, and, based on a power failure being detected, outputs a control signal such that the second power is supplied to the inverter controller and the magnetic bearing controller.

An uninterruptible power supply to be connected between an AC line and a load has a battery system, an inverter, a transformer, and a controller. The battery system stores battery power. The inverter is operatively connected to the battery system. The transformer comprises a primary winding adapted to be connected to the AC line, a load winding adapted to be connected to the load, and an inverter winding operatively connected to the inverter. The controller controls the inverter to operate in a first mode in which the inverter supplies power to the battery system, a second mode in which the inverter supplies power to the load winding using battery power stored in the battery system, and a third mode in which the inverter supplies power to the primary winding using battery power stored in the battery system.

An uninterruptible power supply for providing an output power signal to a load has a ferroresonant transformer, a resonant capacitor operatively connected to the ferroresonant transformer, and an inverter operatively connected to the ferroresonant transformer. The inverter is configured to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having a first change of phase, an upper limit, and a second change of phase. The at least one inverter control signal is pulse-width modulated between the first change of phase and the upper limit, pulse-width modulated between the upper limit and the second change of phase, and held in an ON state when the output power signal is at the upper limit.

A direct current power supply system includes at least one first input source, a second input source, a phase shifting transformer set, a rectifier set and a monitoring module. The phase shifting transformer set is for converting a medium voltage alternating current of the first input source and/or the second input source to a low voltage alternating current. The rectifier set is for rectifying the low voltage AC to a low voltage DC. The phase shifting transformer set and the rectifier set are disposed either in a power supply housing, or in two adjacent power supply housings. The monitoring module includes a phase shifting transformer monitoring unit for retrieving at least one of temperature data, voltage data and current data of the phase shifting transformer set and a rectifier monitoring unit for retrieving at least one of temperature data, voltage data and current data of the rectifier set.

An apparatus for uninterruptible power supply (UPS) comprises a rotating electric machine having a generator winding and a plurality of motor windings. The motor windings of the plurality of motor windings are electrically insulated from the generator winding and from one another. The UPS further comprises, for each motor winding, an energy storage for electric energy and an inverter which outputs an alternating current and via which the energy storage is connected to the respective motor winding.

A ferroresonant transformer assembly comprising, a core, a main shunt, first, second, and third windings, first and second tap connectors, and a selection connector. The first windings configured to be operatively connected to a primary power source. The first tap connector operatively connected to a first intermediate point defined by the third windings. The second tap connector operatively connected to a second intermediate point defined by the third windings. The selection connector operatively connected to the at least one load. Based on voltage requirements of the at least one load, the selection connector is operatively selectively connected to a selected tap connector selected from the first and second tap connectors.

An apparatus for high-speed switching between a plurality of power sources includes a switch-mode isolation transformer. The switch-mode isolation transformer includes a plurality of isolated primary windings. Each of the plurality of isolated primary windings can be electrically isolated from others of the isolated primary windings and selectively couplable to a power source of the plurality of power sources. The switch-mode isolation transformer further includes a secondary winding coupled to a load. The apparatus further includes a controller to selectively couple one of the plurality of power sources through a corresponding isolated primary winding, responsive to detecting an adverse condition in another power source of the plurality of power sources. Other methods and systems are also described.

An emergency lighting and power system comprises a rechargeable battery, an LED driving circuit, and a charging and discharging control circuit. The emergency lighting and power system is intended to automatically supply illumination or power or both in an event of failure of normal power supply. The LED driving circuit is configured to convert a terminal voltage from the rechargeable battery into an AC voltage to operate a luminaire when a line voltage from AC mains is unavailable. The charging and discharging control circuit comprises at least two relay switches configured to sense a loss of normal power supply, to switch between normal power and an emergency power to operate the luminaire in proper situations, and to meet regulatory requirements without operational ambiguity and safety issues.

A grid interconnection system for a power grid includes: a storage battery; a power conversion device that converts power from the storage battery into AC; and an interconnection control device that supplies power from a commercial power supply to a load and supplies power from the power conversion device to the load when the commercial power supply fails. When the commercial power supply is restored, the interconnection control device starts supply of power from the commercial power supply to the load, and stops supply of power from the power conversion device to the load after the supply of power from the commercial power supply to the load is started.