An electrical system for an aircraft with an electric taxi system (ETS), the electrical system may include at least one traction motor, a DC link and at least one traction-motor bidirectional DC-AC converter interposed between the at least one traction motor and the DC link. An engine-driven power source may be configured to provide DC power to the DC link or extract DC power from the DC link. A battery unit may be configured to provide DC power to the DC link or extract DC power from the DC link. An adaptive power controller may be interconnected with the power source, the battery unit and the at least one traction-motor bidirectional DC-AC converter and configured to regulate voltage of DC power delivered to the DC link.

A micro grid system comprises a secondary energy source and a power controller. The secondary energy source is associated with a micro grid that includes a fixed or mobile facility, and the secondary energy source is configured to generate first DC power signal. The power controller is in communication with the secondary energy source and an electric grid, and configured to receive first AC power signal from the electric grid and the first DC power signal from the secondary energy source and output a second AC power signal to loads in communication with the power controller. The power controller comprises an AC to DC frequency converter configured to change frequency and/or voltage of the second AC power signal, a processor, and a memory configured to store instructions that, when executed, cause the processor to control the frequency converter to change the frequency and/or voltage of the second AC power signal.

A micro grid system comprises a secondary energy source and a power controller. The secondary energy source is associated with a micro grid that includes a fixed or mobile facility, and the secondary energy source is configured to generate first DC power signal. The power controller is in communication with the secondary energy source and an electric grid, and configured to receive first AC power signal from the electric grid and the first DC power signal from the secondary energy source and output a second AC power signal to loads in communication with the power controller. The power controller comprises an AC to DC frequency converter configured to change frequency and/or voltage of the second AC power signal, a processor, and a memory configured to store instructions that, when executed, cause the processor to control the frequency converter to change the frequency and/or voltage of the second AC power signal.

A power system for supplying electric power from shore-side to a vessel is presented. The power system includes one or more shore-side converters (101-112) for receiving electric power from a shore-side alternating voltage network (137) and for producing one or more direct voltages. Each shore-side converter can be a controllable converter for controlling the produced direct voltage to be suitable for the vessel in accordance with a control signal received from the vessel, or the vessel may include a direct voltage converter for converting the direct voltage received from the shore-side to be suitable for the vessel. The vessel can be an electric vessel which includes a chargeable battery (132) for supplying electric power to the propulsion system (135) of the vessel.

A power switching apparatus includes a detection circuit, a control circuit and an auxiliary power circuit. The detection circuit comprises a voltage adjusting unit, a delay unit, a first switch unit and an isolation unit. The auxiliary power circuit comprises an auxiliary power input side and an output side. When a main power supplies power normally or the main power stops supplying power but the delay unit continues working in a setting time, the first switch unit is turned on. The isolation unit sends a first signal to the control circuit. The auxiliary power input side does not conduct to the output side. When the main power stops supplying power and the delay unit stops working, the first switch unit is turned off. The isolation unit does not send the first signal to the control circuit. The auxiliary power input side conducts to the output side.

A power switching apparatus includes a detection circuit, a control circuit and an auxiliary power circuit. The detection circuit comprises a voltage adjusting unit, a delay unit, a first switch unit and an isolation unit. The auxiliary power circuit comprises an auxiliary power input side and an output side. When a main power supplies power normally or the main power stops supplying power but the delay unit continues working in a setting time, the first switch unit is turned on. The isolation unit sends a first signal to the control circuit. The auxiliary power input side does not conduct to the output side. When the main power stops supplying power and the delay unit stops working, the first switch unit is turned off. The isolation unit does not send the first signal to the control circuit. The auxiliary power input side conducts to the output side.

An electricity distribution system, arranged to provide low voltage to end users and located at end user locations, includes a first medium voltage line for providing medium voltage and several end user electricity providers associated with respective several end user locations. Each end user electricity provider is couplable to an end user located at the respective end user location, and is arranged to provide low voltage to the end user. The first medium voltage line is provided with a number of branches and the end user electricity providers are each couplable to a respective branch of the medium voltage line via a respective second medium voltage line to receive medium voltage, and are arranged to convert the medium voltage to the low voltage to be provided to an end user.

An electricity distribution system, arranged to provide low voltage to end users and located at end user locations, includes a first medium voltage line for providing medium voltage and several end user electricity providers associated with respective several end user locations. Each end user electricity provider is couplable to an end user located at the respective end user location, and is arranged to provide low voltage to the end user. The first medium voltage line is provided with a number of branches and the end user electricity providers are each couplable to a respective branch of the medium voltage line via a respective second medium voltage line to receive medium voltage, and are arranged to convert the medium voltage to the low voltage to be provided to an end user.

An aircraft electrical network including a first starter generator mechanically coupled to a first shaft of an aircraft main engine. The first starter generator is configured to turn the first shaft of the main engine in a starting mode, and to generate electricity from the first shaft of the gas turbine engine in a generating mode. The network further includes a DC electrical bus electrical coupled to one or more electrical loads and an AC electrical bus electrically coupled to the first starter generator. The DC electrical bus is electrically coupled to the AC electrical bus via a bi-directional AC/DC converter, which is configured to provide AC electrical power from the DC electrical bus to power the first starter generator when the first starter generator is in a starting mode, and DC electrical power to the DC electrical bus when the first starter generator is in a generating mode.

An aircraft electrical network including a first starter generator mechanically coupled to a first shaft of an aircraft main engine. The first starter generator is configured to turn the first shaft of the main engine in a starting mode, and to generate electricity from the first shaft of the gas turbine engine in a generating mode. The network further includes a DC electrical bus electrical coupled to one or more electrical loads and an AC electrical bus electrically coupled to the first starter generator. The DC electrical bus is electrically coupled to the AC electrical bus via a bi-directional AC/DC converter, which is configured to provide AC electrical power from the DC electrical bus to power the first starter generator when the first starter generator is in a starting mode, and DC electrical power to the DC electrical bus when the first starter generator is in a generating mode.