Abstract:
A power control system with a pseudo-power up, an aircraft including the power control system and a method of controlling power in an aircraft. On-board wiring is protected from faults by electronic circuit breakers (ECBs), which may also control AC/DC electrical power supplies of on-board electrical/electronic equipment. A computer processor operating a user interface, e.g., a graphical user interface (GUI), through a display. An on-board store stores the GUI, other computer applications and the current state of each ECB, e.g., in a breaker state table. In a pseudo-power mode up, the stored circuit breaker state is available without providing power to the ECBs and, correspondingly to the coupled on-board electrical systems. When terminated, the system can power off, or proceed to normal power where each ECB is configured according to the breaker state table prior to providing power to protected systems.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   The present invention is a continuation in part of published U.S. Patent Application No.2006/0108873, Ser. No. 11/249,127, entitled “SYSTEMS AND METHODS FOR MONITORING AND CONTROLLING CIRCUIT BREAKERS,” to Hamasaki et al., filed Oct. 11, 2005, now U.S. Pat. No. 7,580,235 which claims priority on provisional application number 60/663,455, filed Mar. 18, 2005, which claims priority on provisional application number 60/618,295, filed Oct. 12, 2004, all assigned to the assignee of the present invention and incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to powering and maintaining power controlled power systems and, more particularly, to powering and maintaining power controlled aircraft power systems protected by electronic circuit breakers. 
   2. Background Description 
   Typical commercial transport aircraft include multiple, complex electrical systems with hundreds of circuit breakers protecting those systems from over-current conditions, traditionally, with Thermal Circuit Breakers (TCB). Thermal circuit breakers normally trip open to protect circuits when enough current passes through the breaker to heat the breaker above a trip point. Additionally, a thermal circuit breaker may be manually opened by pulling on a push/pull breaker switch prior to maintenance, in order to prevent equipment from becoming energized and causing damage, injury, or death. Frequently, tags and locks are attached to open circuit breakers to convey important safety information, and to prevent dangerous closures. Once maintenance is complete, tags and locks must be removed, and the thermal circuit breakers must be manually closed by depressing the push/pull breaker switch. Typical thermal circuit breakers are relatively heavy and require substantial additional aircraft wiring. Since, these heavy thermal circuit breakers are far from optimum or efficient, for this and for many other reasons, some aircraft manufacturers have turned to solid state technology. 
   Instead, these aircraft manufacturers are replacing heavy thermal circuit breakers with remotely located, Solid State Power Controllers (SSPCs) or Electronic Circuit Breakers (ECBs) for improved circuit protection, ease of use and improved personnel safety. A typical state of the art ECB mimics the states of a standard TCB, i.e., closed, opened/tripped, or locked out. Typically, an internal local processor controls each ECB. A centralized interface processor provides control signals over a data bus to coupled ECBs. Each selected ECB switches states in response these control signals and, may respond to the centralized interface processor with an electrical signal that indicates its current breaker state. ECB state information, including electronic representations of tags and locks, is normally stored in internal ECB non-volatile storage. Since ECBs are electronically controlled by the processor, they can be controlled from any processor interface, regardless of the actual ECB location. So, for example, mechanics, pilots, or other users can remotely determine and change the current state of ECBs without leaving the aircraft flight deck. 
   Unfortunately, without electrical power, the breaker state is unknown. Because they are fully electronic/electronically controlled, the ECB must have electrical power to view or alter the current ECB state. This can cause problems when electrical power is initially applied or restored. For example, when the airplane is unpowered, a mechanic is not able to open an unpowered ECB prior to a maintenance activity. If the mechanic proceeds with the activity and, subsequently, power is applied to the airplane, the equipment being maintained could be inadvertently powered. This is a hazardous condition, and consequently, could lead to injury or death to the mechanic, or could cause damage to the airplane. 
   Additionally, if an ECB is replaced during maintenance, the internal state data may be lost or disturbed. This could have the same hazardous consequences, i.e., protected equipment could become inadvertently powered. Furthermore, many ECBs are normally integrated together in a single Line Replaceable Module, (LRM). So, replacing a single such module could impact many individual ECBs and, therefore, many different airplane systems. 
   Accordingly, there is a need for monitoring and inspecting aircraft electronic circuits during maintenance procedures even in unpowered aircraft and especially during power distribution system maintenance. More particularly, there is a need to allow maintenance personnel to engage in such activity without risking damage to the aircraft, and while protecting personnel from injury or death. 
   SUMMARY OF THE INVENTION 
   An embodiment of the present invention includes a power control system with a pseudo-power up, an aircraft including the power control system and a method of controlling power in such an aircraft. On-board electrical wiring is protected from over-current situations or short circuit faults by electronic circuit breakers (ECBs). The AC or DC electrical power supplies of on-board electrical/electronic equipment are also controlled by electronic circuit breakers (ECBs). The power control system includes a computer processor operating a user interface, e.g., a graphical user interface (GUI), through a display. The GUI and other computer applications are stored on-board in storage that also stores the current state of each ECB, e.g., in a breaker state table. While the aircraft is otherwise unpowered, the centralized processor may be operated from battery power in a pseudo-power up mode. In this mode, the GUI display current state information, tags and locks from the breaker state table. Changes may be made to breaker states and changes are stored back in the breaker state table. In this way, a mechanic can determine and control the system protection state. The remainder of the power control system, including the ECBs and, correspondingly, the coupled electrical equipment, remains unpowered. Thereafter, the mechanic may then turn off the centralized processor and return to a completely unpowered mode, or proceed with a normal aircraft power-up sequence. 
   During normal power-up sequence the processor enables each ECB according to the breaker state table prior to powering up the power distribution system. Each ECB validates its configuration, including checking for any state changes. After completing the power up system initialization, the power distribution system energizes aircraft systems with ECBs configured according to the breaker state table configuration. So, any circuit that was disabled when the power distribution system was powered down, remains disabled and is not allowed to energize until after appropriate maintenance action to change the breaker state, e.g., resetting the breaker. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, aspects and advantages will be better understood from the following detailed description of a preferred embodiment of the invention with reference to the drawings, in which: 
       FIG. 1  shows an example of an aircraft electronics power distribution system with a pseudo power-up, wherein even when power is not provided to the power distribution system, a power state may be determined for system Solid State Power Controllers (SSPCs) or Electronic Circuit Breakers (ECBs) according to a preferred embodiment of the present invention. 
       FIG. 2  shows a flow diagram example of operation of a preferred power distribution system. 
       FIG. 3  shows a forward portion of an aircraft at the flight deck housing a power distribution system with powered down status simulation capability. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning now to the drawings and more particularly,  FIG. 1  shows an example of an aircraft electronics power distribution system  100  with a pseudo power-up, wherein even when power is not provided to the power distribution system, a power state may be determined for system Solid State Power Controllers (SSPCs) or Electronic Circuit Breakers (ECBs) according to a preferred embodiment of the present invention. In particular the present invention has application to any state of the art power distribution system that is protected by one or more ECBs, such as the power distribution system described in, for example, published U.S. Patent Application No. 2006/0108873, Ser. No. 11/249,127, entitled “SYSTEMS AND METHODS FOR MONITORING AND CONTROLLING CIRCUIT BREAKERS,” to Hamasaki et al., filed Oct. 11, 2005, assigned to the assignee of the present invention and incorporated herein by reference. 
   The preferred power distribution system  100  is shown in this example with three power supply sources, an Alternating Current (AC) source  102  and two Direct Current (DC) sources  104 ,  106 , each supplying a respective power bus  108 ,  110 ,  112 . Each power bus  108 ,  110 ,  112  supplies power to platform resources or protected electronic systems, represented as loads  114 , and including Flight Deck (F/D) console instrumentation and control  116 ,  118 ,  120 ,  122 ,  124 . In this example power bus  112  includes an alternative or auxiliary supply, i.e., a battery  126 . Although shown only for DC power bus  112 , this is for example only, and each bus  108 ,  110 ,  112  may include auxiliary power. Each of the loads,  114 ,  116 ,  118 ,  120 ,  122 ,  124  is protected by a respective electronic circuit breaker  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146 . 
   The electronic circuit breakers (hereinafter breakers)  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146  are normally located and contained in what are known as Power Distribution Controllers (PDCs). Also, the breakers  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146  are under processor  116  control through connection to one or more data busses  148 , e.g., by operation of the Common-Core Computing Resource (CCR) (an application operating in the processor  116 ) for the Boeing 787. Links between system components, including bus/busses  148  may be hardwired or wireless, depending upon the nature of the components and the particular installation. The CCR may be maintained in on-board storage or memory  118 , which includes non-volatile storage, e.g., hard disk drive storage, Static Random Access Memory (SRAM) with battery back up, or Flash Storage or memory. On-board storage  118  also may include volatile storage as main memory for normal processor  116  operation, e.g., Dynamic Random Access Memory (DRAM) or SRAM. Preferably, on-board storage  118  is in a centralized location, located apart from the power distribution system components. 
   The processor  116  also maintains an up-to-date account of the current state of each breaker  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146  in on-board storage  118 , e.g., in a table  150 , referred to herein as the breaker state table  150 . This example also includes a display  120  and a keyboard  122  for information input/output (I/O). Preferably, breaker status is displayed on the display  120  in a suitable graphical user interface (GUI)  152 , also under processor  116  control and hosted by the CCR. The GUI  152  may include user-selectable indicators or icons (hereinafter, selector icons) presented in a suitable menu. The GUI  152  also may include a typical cursor or pointer that is responsive to manual gestures, e.g., from keyboard  122 , by touch (on a touch-screen display  120 ), by moving a mouse, rolling a trackball  124  or using another suitable input device. Also, the flight deck console includes a “Battery Mode” switch, e.g.,  154  on keyboard  122 , for initiating pseudo power-ups. Normally, except as indicated hereinbelow, the preferred power distribution system  100  operates substantially as described in Hamasaki et al. 
   Breakers  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146  may include, for example, solid state power controllers (SSPCs), solid state relays (SSRs), and/or other electronic power control devices (e.g., electrical load controller functions, or ELCFs) configured to provide a circuit breaker function. The processor  116  also receives signals from each of the breakers  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146  (e.g., state signals) and provides or directs state change signals to the breakers  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146 . Optionally, for some circuit breakers (e.g., mechanical devices), the state of the circuit breaker can be monitored and presented, but not changed in an automated fashion. The breaker state table  150  indicates the current state of each breaker  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146  and as the processor  116  changes state of a breaker the processor  116  updates the corresponding entry in the breaker state table  150  for that particular breaker. 
     FIG. 2  shows a flow diagram example  160  of operation of a preferred power distribution system with reference to the exemplar system  100  of  FIG. 1 . First a pseudo power-up is initiated in step  162 , e.g., by pressing the battery mode switch  154  on flight deck console keyboard  122 . With battery mode selected, in step  164  the processor  116 , the display(s)  120 , keypad  122 , and cursor control device  124  power up and begin running the CCR. However, since the CCR does not provide power to the breakers  130 ,  132 ,  134 ,  136 ,  138 ,  140 , none are enabled; and, as a result, neither are any of the protected loads  114 . In step  166  the CCR retrieves the breaker state table  150  from on-board store  118  and provides an indication of the power on state for each breaker  130 ,  132 ,  134 ,  136 ,  138 ,  140 , e.g., on display  120 . 
   Then, for example, an airplane mechanic can view or alter the state data for any breaker  130 ,  132 ,  134 ,  136 ,  138 ,  140  without risking inadvertently energizing connected circuits, i.e. loads,  114 . Once the mechanic has completed servicing the aircraft, in step  168  the mechanic or other personnel may terminate battery mode and proceed normally with a modified airplane power-up sequence, e.g., initiating normal power up through GUI  152 , but with the breakers  130 ,  132 ,  134 ,  136 ,  138 ,  140  preconditioned according to the state in breaker state table  150 . 
   So, in step  170  the CCR uses the breaker state table  150  information to precondition the breakers according to the respective power down state, such that each breaker  130 ,  132 ,  134 ,  136 ,  138 ,  140  will power up energized or remain un-energized according to the breaker state table  150 . Finally, in step  172 , the breakers  130 ,  132 ,  134 ,  136 ,  138 ,  140  are energized to power up the protected system units and the aircraft operates normally. Thus, with the power distribution system  100  energized, protected system units and circuits (loads  114 ) are powered according to the configuration data in the breaker state table  150 . Further, any unit that was previously disabled (i.e., while the power distribution controllers are powered down), does not energize, for example, until an appropriate maintenance action is taken to change the state, e.g., resetting the breaker. 
     FIG. 3  shows a forward portion of an aircraft  201  in a flight deck  202  substantially similar to Hamasaki et al., housing a power distribution system with capability to simulate status while powered down according to embodiments of the invention. The flight deck  202  may include forward windows  203  providing a forward field of view from the aircraft  201  for an operator seated in a first seat  204   a  and/or a second seat  204   b . Optionally, the forward windows  203  can be replaced with one or more external vision screens that include a visual display of the forward field of view out of the aircraft  201 . A glare shield  205  can be positioned adjacent to the forward windows  203  to reduce the glare on flight instruments  206  positioned on a control pedestal  207  and a forward instrument panel  208 . 
   The flight instruments  206  can include primary flight displays (PFDs)  209  that provide the operators with actual flight parameter information, and multifunction displays (MFDs)  210  that display other operator-selectable information. For example, one or more of the MFDs  210  can present a navigation display  211  containing navigational information. Other MFDs  210  (e.g.,  129  in  FIG. 1 ) can present information pertaining to aircraft circuit breakers, e.g.,  130 ,  132 ,  134 ,  136 ,  138 ,  140  in  FIG. 1 . F/D information (including breaker state information) can also be presented at other display locations, including portable display terminals (not shown) that can be positioned at other locations in the aircraft. 
   So for example, when an aircraft mechanic selects battery mode in a pseudo-power up, the processor and display power up with the display providing breaker information that indicates the last active state of the breakers. Then, the mechanic can identify and service on-board systems without fear of damaging the aircraft or injuring or electrocuting him/herself during normal aircraft power up. Once the mechanic has completed reviewing/changing breaker states, the mechanic can simply shut down and continue servicing the aircraft or, the mechanic or other personnel may proceed with a modified-normal power-up sequence. The CCR uses the breaker state table information to precondition the breakers according to the respective power down state. 
   Advantageously, this pseudo-power up/modified-normal power up may be included as part of the aircraft automatic self-check and configuration process; wherein each SSPC validates its configuration with the CCR, including checking for any state changes to any SSPC. Further, in this modified-normal power-up sequence the processor enables the breakers according to the breaker state table prior to powering up the power distribution system. So, after completing the pseudo-power up system initialization, the power distribution system energizes protected aircraft systems according to the breaker state table configuration. Any circuit that was disabled when the power distribution system was previously powered down, remains disabled and is not allowed to energize until an appropriate maintenance action is taken to change the state, e.g., the breaker is reset. 
   While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims. It is intended that all such variations and modifications fall within the scope of the appended claims. Examples and drawings are, accordingly, to be regarded as illustrative rather than restrictive.