System for providing assured power to a critical load

Claim 2

A power system ( 8 ) for providing uninterrupted electric power to a critical load ( 14 ), comprising: a. a first power source ( 10 ) providing sufficient power to supply the critical load ( 14 ); b. a second power source ( 18 ) comprising at least one fuel cell power plant ( 18 ), the second power source providing sufficient power to supply the critical load ( 14 ) and adapted to be normally substantially continuously connected and providing power to, the critical load ( 14 ); c. a static switch ( 19 ) for selectively connecting and disconnecting the first power source ( 10 ) to the second power source ( 18 ) and (to) the critical load ( 14 ); and d. a switch controller ( 49 , 45 )for controlling the state of the static switch ( 19 ) to connect the first power source ( 10 ) with the critical load ( 14 ) and the second power source ( 18 ) during normal operation of the first power source ( 10 ) and to rapidly disconnect the first power source ( 10 ) from the critical load ( 14 ) and the second power source ( 18 )if and when operation of the first power source ( 10 ) deviates beyond a limit from normal.

Claim 3

The power system ( 8 ) of claim 1 wherein the switch controller ( 49 , 45 ) additionally controls the state of the static switch ( 19 ) to rapidly reconnect the first power source ( 10 ) with the critical load ( 14 ) and the second power source ( 18 ) when the first power source ( 10 ) returns to normal operation.

Claim 4

The power system ( 8 ) of claim 1 wherein the second power source ( 18 ) comprises only one or more fuel cell power plants ( 18 ).

Claim 5

The power system ( 8 ) of claim 1 wherein the static switch ( 19 ) is a solid-state device.

Claim 6

The power system ( 8 ) of claim 4 wherein the solid-state device is a thyristor ( 19 ).

Claim 7

The power system ( 8 ) of claim 1 wherein the first power source ( 10 ) is a utility power grid and wherein each fuel cell power plant ( 18 ) includes a power conditioning system (PCS) for configuring operation of the respective fuel cell ( 18 ) in a grid connected mode or in a grid independent mode in response to mode control signals (D 1 / 401 ′, D 2 / 402 ′), and including a site management controller ( 31 ) connected intermediate the switch controller ( 49 , 45 ) and the power conditioning system (PCS) and responsive to preliminary mode signals (M 1 / 401 , M 2 / 402 ) from the switch controller ( 49 , 45 ) for providing the mode control signals (D 1 / 401 ′, D 2 / 402 ′) to the fuel cell power conditioning system (PCS), whereby the fuel cell power plants ( 18 ) rapidly transition operation between the grid connected and the grid independent modes.

Claim 8

The power system of claim 6 wherein the rapid disconnection of the first power source ( 10 ) from the critical load ( 14 ) and the second power source ( 18 ), and the rapid transitioning of operation of the at least one fuel cell ( 18 ) between the grid connected mode and the grid independent mode occurs within an interval of about 4 milliseconds.

Claim 9

The power system of claim 1 wherein the rapid disconnection of the first power source ( 10 ) from the critical load ( 14 ) and the second power source ( 18 ) occurs within an interval of about 4 milliseconds.

Claim 10

A power system ( 8 ) for providing substantially continuous electric power to at least a critical load ( 14 ), comprising: a. a utility grid power source ( 10 ) providing sufficient power to supply the critical load ( 14 ); b. at least one fuel cell power plant ( 18 ) operating substantially continuously for providing at least sufficient power to supply the critical load ( 14 ), the at least one fuel cell power plant ( 18 ) including a power conditioning system (PCS) for configuring operation of the respective fuel cell ( 18 ) in a grid connected mode or in a grid independent mode in response to mode control signals (D 1 / 401 ′, D 2 / 402 ′), the at least one fuel cell power plant ( 18 ) being normally substantially continuously connected and providing power to, the critical load ( 14 ); c. a static switch ( 19 ) for selectively connecting and disconnecting the grid power source ( 10 ) to the at least one fuel cell power plant ( 18 ) and to the critical load ( 14 ); d. a switch controller ( 49 , 45 ) for controlling the state of the static switch ( 19 ) to connect the grid power source ( 10 ) with the critical load ( 14 ) and the at least one fuel cell power plant ( 18 ) during normal operation of the grid power source ( 10 ) and to disconnect, within a 4 millisecond interval, the grid power source ( 10 ) from the critical load ( 14 ) and the at least one fuel cell power plant ( 18 ) when the grid power source deviates beyond a limit from normal; and e. a site management controller ( 31 ) connected between the switch controller ( 49 , 45 ) and the power conditioning system (PCS) and responsive to preliminary mode signals (M 1 / 401 , M 2 / 402 ) from the switch controller ( 49 , 45 ) for providing the mode control signals (D 1 / 401 ′, D 2 / 402 ′) to the fuel cell power conditioning system (PCS) to cause the at least one fuel cell power plant ( 18 ) to rapidly transition operation, within a 4 millisecond interval, between the grid connected mode and the grid independent mode.

Claim 11

A power system ( 8 ) for providing substantially continuous electric power to at least a critical load ( 14 ), comprising: a. a utility grid power source ( 10 ) providing sufficient power to supply the critical load ( 14 ); b. at least one fuel cell power plant ( 18 ) operating substantially continuously for providing at least sufficient power to supply the critical load ( 14 ), the at least one fuel cell power plant ( 18 ) including a power conditioning system (PCS) for configuring operation of the respective fuel cell ( 18 ) in a grid connected mode or in a grid independent mode in response to mode control signals (D 1 / 401 ′, D 2 / 402 ′), the at least one fuel cell power plant ( 18 ) being normally substantially continuously connected and providing power to, the critical load ( 14 ); c. a static switch ( 19 ) for selectively connecting and disconnecting the grid power source ( 10 ) to the at least one fuel cell power plant ( 18 ) and to the critical load ( 14 ); d. a switch controller ( 49 , 45 ) for controlling the state of the static switch ( 19 ) to connect the grid power source ( 10 ) with the critical load ( 14 ) and the at least one fuel cell power plant ( 18 ) during normal operation of the grid power source ( 10 ) and to disconnect, within a 4 millisecond interval, the grid power source ( 10 ) from the critical load ( 14 ) and the at least one fuel cell power plant ( 18 ) when the grid power source deviates beyond a limit from normal; and e. a site management controller ( 31 ) connected between the switch controller ( 49 , 45 ) and the power conditioning system (PCS) and responsive to preliminary mode signals (M 1 / 401 , M 2 / 402 ) from the switch controller ( 49 , 45 ) for providing the mode control signals (D 1 / 401 ′, D 2 / 402 ′) to the fuel cell power conditioning system (PCS) to cause the at least one fuel cell power plant ( 18 ) to rapidly transition operation, within a 4 millisecond interval, between the grid connected mode and the grid independent mode.

Claim 12

A power system ( 8 ) for providing substantially continuous electric power to at least a critical load ( 14 ), comprising: a. a utility grid power source ( 10 ) providing sufficient power to supply the critical load ( 14 ); b. at least one fuel cell power plant ( 18 ) operating substantially continuously for providing at least sufficient power to supply the critical load ( 14 ), the at least one fuel cell power plant ( 18 ) including a power conditioning system (PCS) for configuring operation of the respective fuel cell ( 18 ) in a grid connected mode or in a grid independent mode in response to mode control signals (D 1 / 401 ′, D 2 / 402 ′), the at least one fuel cell power plant ( 18 ) being normally substantially continuously connected and providing power to, the critical load ( 14 ); c. a static switch ( 19 ) for selectively connecting and disconnecting the grid power source ( 10 ) to the at least one fuel cell power plant ( 18 ) and to the critical load ( 14 ); d. a switch controller ( 49 , 45 ) for controlling the state of the static switch ( 19 ) to connect the grid power source ( 10 ) with the critical load ( 14 ) and the at least one fuel cell power plant ( 18 ) during normal operation of the grid power source ( 10 ) and to disconnect, within less than an 8.3 millisecond interval, the grid power source ( 10 ) from the critical load ( 14 ) and the at least one fuel cell power plant ( 18 ) when the grid power source deviates beyond a limit from normal; and e. a site management controller ( 31 ) connected with the switch controller ( 49 , 45 ) and the power conditioning system (PCS) and responsive to the switch controller ( 49 , 45 ) for providing mode control signals (D 1 / 401 ′, D 2 / 402 ′) to the fuel cell power conditioning system (PCS) to cause the at least one fuel cell power plant ( 18 ) to rapidly transition operation, within less than an 8.3 millisecond interval, between the grid connected mode and the grid independent mode.

Claim 13

A power system ( 8 ) for providing substantially continuous electric power to at least a critical load ( 14 ), comprising: a. a utility grid power source ( 10 ) providing sufficient power to supply the critical load ( 14 ); b. at least one fuel cell power plant ( 18 ) operating substantially continuously for providing at least sufficient power to supply the critical load ( 14 ), the at least one fuel cell power plant ( 18 ) including a power conditioning system (PCS) for configuring operation of the respective fuel cell ( 18 ) in a grid connected mode or in a grid independent mode in response to mode control signals (D 1 / 401 ′, D 2 / 402 ′), the at least one fuel cell power plant ( 18 ) being normally substantially continuously connected and providing power to, the critical load ( 14 ); c. a static switch ( 19 ) for selectively connecting and disconnecting the grid power source ( 10 ) to the at least one fuel cell power plant ( 18 ) and to the critical load ( 14 ); d. a switch controller ( 49 , 45 ) for controlling the state of the static switch ( 19 ) to connect the grid power source ( 10 ) with the critical load ( 14 ) and the at least one fuel cell power plant ( 18 ) during normal operation of the grid power source ( 10 ) and to disconnect, within less than an 8.3 millisecond interval, the grid power source ( 10 ) from the critical load ( 14 ) and the at least one fuel cell power plant ( 18 ) when the grid power source deviates beyond a limit from normal; and e. a site management controller ( 31 ) connected with the switch controller ( 49 , 45 ) and the power conditioning system (PCS) and responsive to the switch controller ( 49 , 45 ) for providing mode control signals (D 1 / 401 ′, D 2 / 402 ′) to the fuel cell power conditioning system (PCS) to cause the at least one fuel cell power plant ( 18 ) to rapidly transition operation, within less than an 8.3 millisecond interval, between the grid connected mode and the grid independent mode.

Claim 14

The power system ( 8 ) of claim 10 wherein the at least one fuel cell power plant ( 18 ) is caused to rapidly transition operation between the grid connected mode and the grid independent mode in an interval of less than about 4 milliseconds.