Abstract:
An integrated skid system integrates the functions of multiple skids into a single skid to reduce the skid footprint and the complexity of the overall system. A multi-motor controller monitors the devices on the integrated skid to maintain proper temperature, pressure and current draw in the devices. Base on this information, the multi-motor controller can make decisions on faults and fault accommodation and communicate with a main controller regarding the operating states of the skid devices via a single serial or Ethernet-type connection.

Description:
TECHNICAL FIELD  
       [0001]     The present invention is directed to fluid handling systems, and more particularly to a skid layout and control system that controls multiple motors in the system.  
       BACKGROUND OF THE INVENTION  
       [0002]     Industrial power plant systems often use gas turbine accessories having several isolated skids linked to a central system controller, each skid carrying various engine components directed to a particular function (e.g., gas turbine bearing lubrication, main electrical generator lubrication, liquid fuel pumping and metering, water injection, hydraulic pumping and control valves, etc.). Each skid may contain a plurality of devices, such as motors, pumps, values, filters, pressure and temperature sensors, thermal controls and other devices that communicate with a central system controller. However, the system controller may be located at a central location away from the skids, requiring a multitude of connections via wires to link the devices to the system controller. These connections between the multiple skids and the system controller are often complicated and costly. The multiple skids also increase the skid footprint in the power plant system, increasing the space and cost needed to implement the system.  
         [0003]     Moreover, the lubrication systems in such an arrangement usually contain three motors and pumps (e.g., two AC motors and one DC motor) to ensure operational availability and safety in case of an emergency shut down. These additional features further increase the complexity of the overall power plant system, causing high installation and commissioning costs.  
         [0004]     There is a desire for a power plant system that is simpler and more cost-effective to implement.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention is directed to an integrated skid and a multi-motor controller that integrates the functions of multiple skids into a single skid, thereby reducing the skid footprint and the complexity of the overall system. All of the devices on the integrated skid are monitored and controlled by the multi-motor controller to maintain proper temperature, pressure and current draw in the devices. Base on this information, the multi-motor controller can make decisions on faults and fault accommodation and communicate with a main controller regarding the operating states of the skid devices via a single serial or Ethernet-type connection, eliminating a significant amount of wiring. The multi-motor controller therefore provides redundant and fault-tolerant operation of the devices in the integrated skid without requiring actual redundancy in the skid devices themselves.  
         [0006]     In one embodiment, the multi-motor controller can operate from either AC power or DC power, eliminating the need for separate DC motors and pumps in the system. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a representative plan view of one example of an integrated skid illustrating the concepts of one embodiment of the invention;  
         [0008]      FIG. 2  is a side view of the integrated skid of  FIG. 1 ;  
         [0009]      FIG. 3  is a representative diagram of a multi-motor controller according to one embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0010]      FIGS. 1 and 2  are representative diagrams of an integrated skid system  100  to illustrate the broad concept of the invention. The example shown in  FIGS. 1 and 2  is meant for illustrative purposes and is not meant to be limiting in any way. Those of ordinary skill in the art will understand that any number and type of system components and configurations can be used without departing from the scope of the invention.  
         [0011]     As noted above, conventional plant systems tend to separate gas turbine engine accessory devices according to their functions into isolated skids, each skid having its own associated motors, controllers, sensors and other devices. The integrated skid system  100  shown in  FIG. 1  integrates devices  101  having disparate functions onto a single skid  102  or other platform and controls these devices  101  via a single multi-motor controller  104  associated with the system  100 . In the illustrated embodiment, two motors  106  and their associated devices  101  (e.g., oil pumps  108 , oil valves  110 , filters  112 , etc.) are disposed on the same skid  102  even though they carry out different functions. The multi-motor controller  104  monitors and controls the devices  101  on the skid system  100 , making it possible to control operation of a given device based on the operating states of other devices  101  on the same skid  102 . As a result, devices  101  can be shared among separate engines, minimizing the total number of devices  101  needed to support the engines without sacrificing redundancy and fault-tolerance.  
         [0012]     For example, in a conventional system, a given engine may require four motors and their associated pump components: one primary motor and one backup motor for each engine. Thus, two engines would normally require a total of four motor and associated pump components because the motors are isolated from each other and controlled independently. Integrating the components allows the total number of motors for the two engines to be reduced to three: one primary motor for each engine and a backup motor shared between the two engines, to be used on whichever engine is experiencing a motor problem. Because the multi-motor controller  104  receives sensor data from multiple engines and devices  101  and makes decisions based on the received data, it can detect which engine is having the problem and switch the backup motor to either engine. Similar device sharing can be implemented for other devices  101 , such as water and fuel pumps, in the system  100 . Thus, the intelligent capability provided by the multi-motor controller  104  allows control over device operation to enable sharing of devices  101  among engines.  
         [0013]     In the illustrated embodiment, the multi-motor controller  104  communicates with a system controller  120  via a simple connector  122 , such as a serial or Ethernet-type connection. In this embodiment, the decision-making functions regarding how to control a device (e.g., a motor operating speed) are conducted by the multi-motor controller  104 , while the actual plant control is conducted by the system controller  120 . In this way, the system controller  120  can be kept very simple. Separating the plant control functions from the intelligent functions also allows a single system controller  120  to control devices  101  associated with a plurality of multi-motor controllers  104  with a minimal increase in the number of connections in the overall system, on the order of the number of additional integrated skids  100  rather than the number of additional devices  101 .  
         [0014]     The multi-motor controller  104  itself has the intelligence and the power needed to control the various devices  101 , such as the motors, in the skid system  100 . The devices  101  in the skid system  100  have sensors that feed sensor data to the multi-motor controller  104  for the controller  104  to analyze. The multi-motor controller  104  may then, if needed, instruct the system controller  120  to actually control the devices  101  based on the analysis it conducted. As a result, the multi-motor controller  104  can conduct fault-tolerance and correction if the sensor data obtained from the devices  101  indicates the presence of a potential problem.  
         [0015]     The intelligent control provided by the multi-motor controller  104  is particularly useful in minimizing the number of devices needed to control critical functions. For example, conventional turbine engine systems include both two AC motors and a backup DC motor to ensure that oil continues to be pumped to the generator by the DC motor in the case of an AC power failure, preventing the generator bearings from being damaged. Current system controllers  120  simply turn on the DC motor in reaction to the power failure. By contrast, the multi-motor controller  104  in the inventive system makes it possible to use a motor that can run from both an AC source and a DC source so that the motor can be simply switched to operate from the DC source in case the multi-motor controller  104  detects an AC power failure. Thus, the intelligent control provided by the multi-motor controller  104  allows all of the DC pumps and motors to be eliminated completely from the system  100 , greatly reducing the total hardware in the system  100 . Those of ordinary skill in the art will be able to see that the multi-motor controller  104  makes other hardware reductions possible within the scope of the invention.  
         [0016]      FIG. 3  illustrates an example of one particular embodiment of the multi-motor controller  104  that may be used in the inventive system  100 . The controller  104  is not limited to the illustrated configuration, and other configurations may be used without departing from the scope of the invention. In the illustrated embodiment, the multi-motor controller  104  is a modular controller that allows boards to be inserted and removed based on the specific devices  101  on the skid  100 . A channel rack  200  has edge connectors  204  that can accommodate various plug-ins and controller cards to provide various functionalities to the controller  104 . In the illustrated embodiment, for example, a housekeeping card  206  and a PCI I/O board  208  may be plugged into the channel rack  200 . As shown in  FIG. 3 , other boards, such as a PC Ethernet card  210  or a standard PCI I/O data card  212 , may also be connected to the channel rack  200  if desired.  
         [0017]     A main engine control I/O card  214  acts as an interface between the multi-motor controller  104  and the system controller  120 . The multi-motor controller  104  can send instructions via main engine control I/O card  214  to the system controller  120  to, for example, turn devices on and off. The system controller  120  may also send information (e.g., requested engine speed, engine mode status, start, stop, synchronize, load shed, synchronous condensing, etc.) to the multi-motor controller  104  via the main engine control I/O card  214 .  
         [0018]     Each of the devices  101  in the skid system  100  may have its own associated sensor  216  to provide information on the health and operating state of the device  101 . Collectively, the sensors  216  may collectively feed data into a connector I/O port  218  on the rack  200 , providing the data needed for the controller  104  to decide how to control the devices. The particular sensor devices  216  that are needed in a given system  100  can vary depending on the specific devices on the skid. For example, the input/output devices  216  may correspond to pressure and temperature flow transducers, current meters, DC meters, AC meters, etc., all of which can be plugged into the connector I/O port  218 . This plug-in capability further illustrates the flexible, modular nature of the multi-motor controller  104  because any combination of devices  216  can be included in the system  100  without complicated modifications to the system  100  itself.  
         [0019]     Various miscellaneous control functions  220  may be included to control operation of devices that do not require intelligent control, such as constant speed motors, heaters, fans, relays, or other smaller devices that are either on or off (i.e., binary) rather than variable. This allows processing resources in the controller  104  to be reserved for variable control devices, such as variable speed motors.  
         [0020]     A local power supply module  222  may also be connected to the rack  200  to act as a switch to backup DC power supply that is tapped in case of an AC power failure.  
         [0021]     As noted above, a given skid system  100  may have multiple motors  106  (e.g., an oil system motor, a water system motor, a fuel system motor, a ventilator motor, etc.). The embodiment shown in  FIG. 3  includes a digital signal processor (DSP) and gate driver interface card  224 . Each of these cards  224  is connected to the rack  200  by their own dedicated edge connectors  204  to link the rack  200  with a corresponding motor commutation module  226 . Although the illustrated embodiment includes one DSP card  224  and motor commutation module  226  with each motor, some sharing among the cards  224  and modules  226  can be arranged among multiple motors if selected motors do not operate at the same time.  
         [0022]     For example, a starter motor and a fuel motor would require separate cards  224  and modules  226  because they are used simultaneously when an engine is started. The starter motor and a motor that controls water injection into the motor, however, can share a single card  224  and module  226  because water injection is not conducted during the engine start operation. As another example, a main system and a backup system may share the same card  224  and module  226  because the backup system will only operate if the main system fails.  
         [0023]     The DSP and gate driver interface cards  224  act as the motor controllers and the motor commutation modules  226  act as the switches that actually switch different legs of the motor to cause the motor to turn at a given speed. The DSP and gate driver interface cards  224  calculate the desired motor speed, current limits, and commutation pattern required to properly rotate the specific motor type being used (i.e., induction motor, permanent magnet motor, etc.). The DSP and gate driver interface cards  224  can be programmed to drive various types and size of motors, if desired. The motor commutation module  226  contains high power bus bars and high power switches, such as insulated gate bipolar transistors (IGBT) that actually switch the current on and off to the various phases of the motor being controlled.  
         [0024]     By combining separate system devices into an integrated skid package and controlling the devices via a common intelligent multi-motor controller, the invention provides improved system functionality with fewer devices in fluid handling systems. Rather than relying on the system controller alone, which simply turns the motors and associated devices on and off, the intelligent controller used in the invention is able to make decisions on when the motors will go on and off based on the operation of other motors and devices in the system. As a result, the inventive system provides redundancy and fault-tolerance via intelligent device control rather than through extra redundant devices. Moreover, moving devices having different functions onto a common skid reduces the overall plant footprint, making the system simpler and less costly to implement.  
         [0025]     It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby.