Electric power devices and control methods are provided which automatically select a line voltage or phase voltage of an AC voltage supply. The electric power device includes a switchable circuit, a sensor and a switch control. The switchable circuit connects to the AC voltage supply, and includes multiple switchable elements. The sensor ascertains a voltage level of the AC voltage supply, and the switch control automatically establishes a configuration of the switchable circuit through control of the multiple switchable elements. The switch control couples the electric power device in a line-line (delta) configuration to the AC voltage supply when the voltage level is in a first voltage range, and a line-neutral (wye) configuration when the voltage level is in a second voltage range.

Electric power devices and control methods are provided which automatically select a line voltage or phase voltage of an AC voltage supply. The electric power device includes a switchable circuit, a sensor and a switch control. The switchable circuit connects to the AC voltage supply, and includes multiple switchable elements. The sensor ascertains a voltage level of the AC voltage supply, and the switch control automatically establishes a configuration of the switchable circuit through control of the multiple switchable elements. The switch control couples the electric power device in a line-line (delta) configuration to the AC voltage supply when the voltage level is in a first voltage range, and a line-neutral (wye) configuration when the voltage level is in a second voltage range.

In the field of line commutated converters, for use in high voltage direct current (HVDC) power transmission, a line commutated converter (10) comprises a plurality of converter limbs (12A, 12B, 12C) that extend between first and second DC terminals (16, 18). Each converter limb (12A, 12B, 12C) includes first and second limb portions (22, 24) which are separated by an AC terminal (26A, 26B, 26C). The first limb portions (22) together define a first limb portion group (28) and the second limb portions (24) together define a second limb portion group (30). Each limb portion (22, 24) includes at least one switching element (36, 36 2, 36 3, 36 4, 36, 36 6) that is configured to turn on and conduct current when it is forward biased and it receives a turn on signal and to naturally turn off and no longer conduct current when it is reverse biased and the current flowing through it falls to zero. The converter (10) also includes a control unit (38) which is programmed to, in use, control successive switching of the switching elements (36, 36 2, 36 3, 36 4, 36, 36 6) whereby a first switching element (36) in the first limb portion group (28) and a second switching element (36 2) in the second limb portion group (30) and a different converter limb (12B, 12C) to the first switching element (36) connect two corresponding AC terminals (26A, 26C in series between the first and second DC terminals (16, 18). The control unit (38) is further programmed to send a third switching element (36 3) in the first limb portion group (28) a turn on signal whereby the third switching element (36 3) turns on and begins to conduct current while the current flowing through the first switching element (36) begins to fall to zero and the first switching element (36) prepares to naturally turn off, and to subsequently send a fourth switching element (36 4) in the second limb portion group (30) and a different converter limb (12A, 12C) to the third switching element (36 3) a turn on signal whereby the fourth switching element turns (36 4) on and begins to conduct current while the current flowing through the second switching element (36 2) begins to fall to zero and the second switching element (36 2) prepares to naturally turn off. The control unit (38) also checks for an abnormal current flow (56) associated with the first switching element (36) during a fini

Since a power converter including a modular multilevel converter uses a large number of cells each combining a plurality of switching elements and a DC capacitor, there is a problem of conduction loss due to the switching elements. The conduction loss is reduced by connecting a bypass circuit between terminals of each of the cells, controlling to open and close the switching element, and controlling to short-circuit the bypass circuit connected to the cell controlled to output zero voltage.

A power supply circuit includes: an alternating current-to-direct current (AC-to-DC) converter, a transformer, a first current switch, a switch control circuit and a power factor enhancement circuit. The AC-to-DC converter converts an AC power signal into a DC power signal. The transformer includes a primary side and a secondary side, where a first terminal of the primary side is coupled to the AC-to-DC converter, a second terminal of the secondary side is coupled to a ground voltage level, a first terminal of the first current switch is coupled to a second terminal of the primary side, and a second terminal of the first current switch is coupled to the ground voltage level through an impedance component. The power factor enhancement circuit selectively adjusts a zero current detection voltage to make the switch control circuit set the first current switch to be in a conducting state.

Embodiments are directed to power conversion circuits including a bypass circuit for bypassing an inrush current limiting resistor. In one embodiment, a power conversion circuit is provided that includes a bridge rectifier, a current limiting resistor, a controllable current switching device, and a driver. The current limiting resistor has a first terminal coupled to an output terminal of the bridge rectifier and a second terminal coupled to an electrical ground. The controllable current switching device has conduction terminals coupled in parallel with respect to the current limiting resistor. The driver is coupled between the first terminal of the current limiting resistor and a control terminal of the current switching device, and the driver controls an operation of the current switching device based on a current through the current limiting resistor.

A dual-comparator rectifier circuit of a wireless power receiver includes a receive coil configured to generate a current in response to receiving power through electromagnetic waves from a wireless power transmitter and a bridge circuit. The bridge circuit includes four branches, and one node of each of the four branches is coupled to one of a first node or a second node of the receive coil. A first branch and a second branch of the four branches are coupled to the first node and the second node of the receive coil and include a first circuit and a second circuit, respectively. The first circuit includes a first comparator and a first switch circuit and the second circuit includes a second comparator and a second switch circuit. The first circuit and the second circuit can set a dynamic turn-on threshold for the first switch circuit and the second switch circuit, respectively.

A method of commutation in a matrix rectifier from an active vector to a zero vector includes two steps. A method of commutation in a matrix rectifier from a zero vector to an active vector includes three steps.

An AC-DC conversion device that includes a major circuit portion and a control circuit. The major circuit portion includes a converter in which multiple switch portions in a bridge connection include separately-excited switching elements and snubber circuits connected in parallel with the switching elements; and the major circuit portion is connected to an alternating current power supply and a direct current circuit and applies, to the direct current circuit, an alternating current voltage applied from the alternating current power supply by an ON of the multiple switch portions. The control circuit controls the voltage applied to the direct current circuit by controlling the ON timing of the multiple switch portions by inputting a control pulse to each of the multiple switch portions.

An AC-DC conversion device that includes a major circuit portion and a control circuit is provided. The major circuit portion includes a converter in which multiple switch portions in a bridge connection include separately-excited switching elements and snubber circuits connected in parallel with the switching elements; and the major circuit portion is connected to an alternating current power supply and a direct current circuit and applies, to the direct current circuit, an alternating current voltage applied from the alternating current power supply by an ON of the multiple switch portions. The control circuit controls the voltage applied to the direct current circuit by controlling the ON timing of the multiple switch portions by inputting a control pulse to each of the multiple switch portions.