A load controller according to an embodiment includes a switching unit, a power source unit, and a control unit. The switching unit controls supply of power from an AC power supply to a load by selectively connecting or disconnecting the load to/from the AC power supply. The power source unit converts AC power supplied from the AC power supply into DC power. The control unit operates with the DC power supplied from the power source unit and controls the switching unit. The power source unit includes a constant-voltage source and a constant-current source. The constant-voltage source keeps a DC voltage to be output to the control unit a constant voltage. The constant-current source keeps a DC current to be supplied via the constant-voltage source to the control unit a constant current.

Provided is a wireless power receiving unit with a self-regulation rectifier. In one embodiment, the wireless power receiving unit includes a resonator configured to receive wireless power; and a self-regulation rectifier unit including a rectifier configured to apply a rectifier output voltage to a load by converting alternating-current (AC) power received from the resonator into direct-current (DC) power, and a switching device located at a rear end of the rectifier and configured to self-regulate the rectifier output voltage.

A load controller according to an embodiment includes a switching unit, a power source unit, and a control unit. The switching unit controls supply of power from an AC power supply to a load by selectively connecting or disconnecting the load to/from the AC power supply. The power source unit converts AC power supplied from the AC power supply into DC power. The control unit operates with the DC power supplied from the power source unit and controls the switching unit. The power source unit includes a constant-voltage source and a constant-current source. The constant-voltage source keeps a DC voltage to be output to the control unit a constant voltage. The constant-current source keeps a DC current to be supplied via the constant-voltage source to the control unit a constant current.

A control grid for a cathode including a plurality of grid cells, with each grid cell including a deflecting layer, an insulating layer and a grid layer. The deflecting layer is in contact with the cathode; the insulating layer is between the deflecting layer and the grid layer; and the grid layer is at a positive voltage relative to the cathode, such that a voltage gradient is created between the cathode and the grid layer which accelerates electrons emitted by the cathode away from the cathode.

A control grid for a cathode including a plurality of grid cells, with each grid cell including a deflecting layer, an insulating layer and a grid layer. The deflecting layer is in contact with the cathode; the insulating layer is between the deflecting layer and the grid layer; and the grid layer is at a positive voltage relative to the cathode, such that a voltage gradient is created between the cathode and the grid layer which accelerates electrons emitted by the cathode away from the cathode.

A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to switch on one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and switch off the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to switch on one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and switch off the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to switch on one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and switch off the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.