A power transfer system includes a first branch including a controlled switch and a second branch including a variable frequency converter, in parallel between an AC network and a reversible pump-turbine, the variable frequency converter includes: a first AC/DC converter having a first DC interface, and a second AC/DC converter having a second DC interface, the first and second DC interfaces being connected by a DC link, a control circuit having a first mode wherein it simultaneously opens the switch and it transfers electrical power until it reaches the same frequency on two AC interfaces, and having a second mode wherein it closes the switch of the first branch; an energy storage system; and a switching system for selectively connecting the energy storage system to the DC link.

A power transfer system includes a first branch including a controlled switch and a second branch including a variable frequency converter, in parallel between an AC network and a reversible pump-turbine, the variable frequency converter includes: a first AC/DC converter having a first DC interface, and a second AC/DC converter having a second DC interface, the first and second DC interfaces being connected by a DC link, a control circuit having a first mode wherein it simultaneously opens the switch and it transfers electrical power until it reaches the same frequency on two AC interfaces, and having a second mode wherein it closes the switch of the first branch; an energy storage system; and a switching system for selectively connecting the energy storage system to the DC link.

Provided is a reactor that can prevent a short circuit from occurring between turns of a coil even if a foreign object is present between turns. The reactor includes: an edgewise coil formed by a flat rectangular wire; a magnetic core; and a molded resin part that covers at least a portion of the magnetic core, wherein the edgewise coil includes a plurality of turns configured to form a rectangular shape, each of the plurality of turns includes four straight portions, and four curved corner portions that connect the adjacent straight portions to each other, each of the four corner portions includes an outer region in which a gap is provided between the adjacent turns, and the molded resin part is present in at least two of the gaps that are diagonally opposite to each other.

An integrated voltage regulator comprises a plurality of semiconductor devices and a circuit board including a plurality of thermally conductive inlays. At least one of the plurality of electronic devices is thermally coupled to at least one of the plurality of thermally conductive inlays. A substrate is thermally coupled to the circuit board and to the plurality of thermally conductive inlays.

A power converter comprises a chassis and an AC connector, a low-voltage DC connector and a high-voltage DC connector at an exterior surface of the chassis. An AC-DC converter circuit is positioned at least partially within the chassis and is coupled to the AC connector. A first converter circuit is positioned at least partially within the chassis and is coupled to the AC-DC converter circuit and to a high-voltage DC bus. The high-voltage DC bus is connected to the high-voltage DC connector. A second converter circuit is positioned at least partially within the chassis and is coupled to the high-voltage DC bus to a low-voltage DC bus. The low-voltage DC bus is connected to the low-voltage DC connector.

A power converter comprises a chassis and an AC connector, a low-voltage DC connector and a high-voltage DC connector at an exterior surface of the chassis. An AC-DC converter circuit is positioned at least partially within the chassis and is coupled to the AC connector. A first converter circuit is positioned at least partially within the chassis and is coupled to the AC-DC converter circuit and to a high-voltage DC bus. The high-voltage DC bus is connected to the high-voltage DC connector. A second converter circuit is positioned at least partially within the chassis and is coupled to the high-voltage DC bus to a low-voltage DC bus. The low-voltage DC bus is connected to the low-voltage DC connector.

An electrical system including a three phase AC input supply and three or more H-bridge converter cells. Each H-bridge converter cell has: an active front end rectifier for receiving the three phase AC input supply and transforming it into a DC supply, thereby providing a rectifier current i.sub.i; a capacitor suitable to receive a capacitor current i.sub.C, the capacitor smoothing the DC supply; and an inverter suitable to receive an inverter current i.sub.o, wherein i.sub.o=i.sub.i−i.sub.C, said inverter transforming the received inverter current i.sub.o into a single phase AC supply. The system also including a control subsystem, which provides a signal to each active front end rectifier to vary its respective rectifier current i.sub.i such that the difference between the rectifier current i.sub.i, provided by the active front end rectifier, and the inverter current i.sub.o, received by the inverter, is substantially zero.

An electrical system including a three phase AC input supply and three or more H-bridge converter cells. Each H-bridge converter cell has: an active front end rectifier for receiving the three phase AC input supply and transforming it into a DC supply, thereby providing a rectifier current i.sub.i; a capacitor suitable to receive a capacitor current i.sub.C, the capacitor smoothing the DC supply; and an inverter suitable to receive an inverter current i.sub.o, wherein i.sub.o=i.sub.i−i.sub.C, said inverter transforming the received inverter current i.sub.o into a single phase AC supply. The system also including a control subsystem, which provides a signal to each active front end rectifier to vary its respective rectifier current i.sub.i such that the difference between the rectifier current i.sub.i, provided by the active front end rectifier, and the inverter current i.sub.o, received by the inverter, is substantially zero.

A current control method and system for a voltage asymmetry fault is disclosed. When a voltage asymmetry fault occurs, a first current limit value is obtained based on a post-fault positive-sequence voltage and a pre-fault positive-sequence reactive current, and a second current limit value is obtained based on a post-fault negative-sequence voltage and a pre-fault negative-sequence voltage. A third current limit value and a fourth current limit value are obtained based on the first current limit value and the second current limit value. A magnitude of a positive-sequence reactive current is limited by using the third current limit value, and a magnitude of a negative-sequence reactive current is limited by using the fourth current limit value.

A current control method and system for a voltage asymmetry fault is disclosed. When a voltage asymmetry fault occurs, a first current limit value is obtained based on a post-fault positive-sequence voltage and a pre-fault positive-sequence reactive current, and a second current limit value is obtained based on a post-fault negative-sequence voltage and a pre-fault negative-sequence voltage. A third current limit value and a fourth current limit value are obtained based on the first current limit value and the second current limit value. A magnitude of a positive-sequence reactive current is limited by using the third current limit value, and a magnitude of a negative-sequence reactive current is limited by using the fourth current limit value.