Patent Publication Number: US-2018045791-A1

Title: Power supply condition monitor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This invention is related to the disclosure of U.S. Pat. No. 8,103,463, which issued on Jan. 24, 2015. The entire disclosures of U.S. Pat. No. 8,103,463 are incorporated herein by reference. 
    
    
     FEDERAL RESEARCH STATEMENT 
     This invention was made with government support under Contract No. W911W6-08-C-0053 awarded by the Army. The government has certain rights in the invention. 
    
    
     BACKGROUND OF THE INVENTION 
     The subject matter disclosed herein relates to a monitor and, more particularly, to an online power supply condition monitor. 
     During normal operations of electronic equipment, power supplies convert and condition source power to a signal that is useful and protective for the supplied electronic system. However, undetected degradation of power supplies can result in catastrophic failure that can be damaging to the supplied system and other source connected electronic systems. Thus, current technology for detecting degradation of power supplies relates to systems and methods for detecting degradation (prior to functional failure) of power supplies and for predicting remaining useful life prior to functional and catastrophic failures. Such systems and methods generally operate within a testing environment but do not address degradation detection within an operational environment. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to one aspect of the invention, a method for monitoring a health state of electronic equipment is provided and includes capturing data of an operation of the electronic equipment over a sampling range of predefined length, storing captured data in a storage unit and characterizing a behavior of the operation of the electronic equipment based on an analysis of stored captured data in an event a predefined time has expired or the storage unit has reached maximum capacity. 
     In accordance with additional or alternative embodiments, the capturing includes collecting current and voltage samples at an input and an output of a power supply of the electronic equipment. 
     In accordance with additional or alternative embodiments, the capturing includes data sampling. 
     In accordance with additional or alternative embodiments, the capturing is conducted by sensors embedded in the electronic equipment. 
     In accordance with additional or alternative embodiments, the capturing is conducted by sensors disposed externally with respect to the electronic equipment. 
     In accordance with additional or alternative embodiments, the electronic equipment includes a power converter. 
     In accordance with additional or alternative embodiments, the method further includes deferring the characterizing until the predefined time expires or the storage unit reaches the maximum capacity. 
     In accordance with additional or alternative embodiments, the characterizing includes characterizing a behavior of input versus output power in the electrical equipment. 
     According to another aspect of the invention, a method for monitoring a health state of electronic equipment of a rotorcraft is provided. The method includes capturing current and voltage samples from an input power and an output power of a power converter of the electronic equipment over a sampling range of predefined length, storing data reflective of the captured current and voltage samples in a storage unit having a maximum capacity, deferring a characterization of the stored data until a predefined time expires or the storage unit reaches the maximum capacity and characterizing a behavior of the input power and the output power based on an analysis of the stored data in an event the predefined time has expired or the storage unit has reached the maximum capacity. 
     In accordance with additional or alternative embodiments, the capturing is conducted by one or both of sensors embedded in the power converter and sensors disposed externally with respect to the power converter. 
     According to another aspect of the invention, a rotorcraft is provided and includes an airframe on which main and auxiliary rotors are operably disposed to be drivable to rotate relative to the airframe to generate lift and thrust, electronic equipment disposed about the airframe, an electronic power supply disposed to provide electric power to the electronic equipment and a power supply control system coupled to the electronic power supply to control a provision of the electric power to the electronic equipment. The power supply control system includes a processing system to execute the methods for monitoring a health state of electronic equipment. 
     In accordance with additional or alternative embodiments, the power supply control system includes a power converter. 
     In accordance with additional or alternative embodiments, the processing system is embedded in the power converter. 
     In accordance with additional or alternative embodiments, the processing system is disposed externally with respect to the power converter. 
     In accordance with additional or alternative embodiments, the processing system includes a health and usage monitoring system (HUMS). 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a side view of a coaxial, counter-rotating rotorcraft; 
         FIG. 2  is a front, elevation view of the rotorcraft of  FIG. 1 ; 
         FIG. 3  is a schematic diagram of components of the rotorcraft of  FIG. 1 ; 
         FIG. 4  is a schematic diagram of a health monitoring system of the rotorcraft of  FIGS. 1-3 ; 
         FIG. 5  is an illustrative schematic of an electric power converter having an embedded health monitoring system; 
         FIG. 6  is a block diagram of an exemplary embedded health monitoring system; 
         FIG. 7  is an illustrative schematic of an electric power converter having an external health monitoring system; 
         FIG. 8  is a block diagram of an exemplary embedded health monitoring system; 
         FIG. 9  is a flow diagram illustrating a method for monitoring a health state of electronic equipment. 
     
    
    
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     As will be described below, detection of power supply degradation and prediction of remaining useful life prior to functional and catastrophic failures is provided by a system and method of continuous monitoring within an operational environment that overcomes sampling, processing and data management challenges. The system and method provide for aperiodic current and voltage samples to be collected at an input and an output of a monitored power supply, provide input to an embedded processor connected to sensors and include an intelligent data measurement scheme that controls measurement collection to ensure that a sufficient operational range is captured, that minimizes required processing power and optimizes data sampled to available storage and that characterizes the behavior of the input power versus the output power. The system and method further maintain a history to support trend analysis and prediction. 
     With reference to  FIGS. 1-3 , a coaxial rotorcraft  1  is provided and may be configured for example as a coaxial, counter-rotating helicopter or some other fixed or variable wing aircraft with single or multiple rotors. The rotorcraft  1  has an airframe  2  that is sized to accommodate a pilot and, in some cases, one or more crewmen and/or passengers as well as control features and a flight computer  10  (see  FIG. 3 ). The airframe  2  has a top portion  3  and a tail portion  4  that extends in the aft direction. The rotorcraft  1  further includes a main rotor assembly  5  at the top portion  3  of the airframe  2 , an auxiliary propulsor  6  at the tail portion  4 , an engine  7  (see  FIG. 3 ) and a transmission  8  (see  FIG. 3 ). The engine  7  may be disposed within or on the airframe  2  and is configured to generate power to drive respective rotations of the main rotor assembly  5  and the auxiliary propulsor  6 . The transmission  8  is similarly disposed within or on the airframe  2  and is configured to transmit the power from the engine  7  to the main rotor assembly  5  and the auxiliary propulsor  6 . 
     The main rotor assembly  5  includes a first or upper rotor  50  and a second or lower rotor  51 . The upper rotor  50  includes a rotor shaft  501 , a hub  502  and blades  503  extending radially outwardly from the hub  502 . The rotor shaft  501  and the hub  502  are rotatable in a first direction about rotational axis RA, which is defined through the airframe  2 , to drive rotations of the blades  503  about the rotational axis RA in the first direction. The lower rotor  51  includes a rotor shaft  511 , a hub  512  and blades  513  extending radially outwardly from the hub  512 . The rotor shaft  511  and the hub  512  are rotatable in a second direction about the rotational axis RA, which is opposite the first direction, to drive rotations of the blades  513  about the rotational axis RA in the second direction. The auxiliary propulsor  6  has a similar structure with an axis of rotation that is generally aligned with a longitudinal axis of the tail portion  4 . 
     The blades  503 ,  513  are pivotable about respective pitch axes PA that run along respective longitudinal lengths of the blades  503 ,  513 . This pitching can include lateral cyclic pitching, longitudinal cyclic pitching and collective pitching. Lateral cyclic pitching varies blade pitch with left and right movements and tends to tilt the rotor disks formed by the blades  503  and  513  to the left and right to induce roll movements. Longitudinal cyclic pitching varies blade pitch with fore and aft movements and tends to tilt the rotor disks forward and back to induce pitch nose up or down movements. Collective pitching refers to collective angle of attack control for the blades  503 ,  513  to increase/decrease torque. 
     When driven to rotate by the engine  7  via the transmission  8 , the main rotor assembly  5  generates lift and the auxiliary propulsor  6  generates thrust. The pilot (and crew) and the flight computer  10  can cyclically and collectively control the pitching of the blades  503 ,  513  of at least the main rotor assembly  5  in order to control the flight and navigation of the rotorcraft  1  in accordance with pilot/crew inputted commands and current flight conditions. 
     The rotorcraft  1  may also include a system of sensors  30 . The system of sensors  30  may include a plurality of individual sensors  31  that are respectively disposed about the airframe  2  on rotating or non-rotating frames. That is, the sensors  31  can be disposed on the hubs  502 ,  512 , the blades  503 ,  513  or on/in the airframe  2 . 
     With reference to  FIG. 4 , the rotorcraft  1  of  FIGS. 1-3  may further include electronic equipment  40  disposed about the airframe  2 , an electronic power supply  50  disposed to provide electric power to the electronic equipment  40  and a power supply control system  60 . The electronic equipment  40  can include the system of sensors  30  or components thereof as well as additional electronic equipment used by the flight computer  10  or other on-board computing or electronic devices. The electronic power supply  50  includes at least a power converter  51  (i.e., an AC-DC power converter). The power converter  51  may be provided as a component of the electrical equipment  40  as well. 
     The power supply control system  60  is coupled to the electronic power supply  50  and is configured to control a provision of the electric power to the electronic equipment  40 . To this end, the power supply control system  60  includes a processing system  61  that executes the methods described below. With reference to  FIGS. 5-8 , various hardware configurations or embodiments for the power supply control system  60  exist. These include, but are not limited to the possibility of the power supply control system  60  being a component of a health and usage monitoring system (HUMS). 
     The power supply control system  60  illustrated in  FIGS. 5 and 6  utilizes available hardware within the power converter  51 , such as sensors, to measure input currents and voltages from input power lines  601  and output currents and voltages at output power lines  602 . As shown in  FIG. 6 , the power supply control system  60  may be embedded in the power converter  51  with an internal power bus  603 , which includes the input power lines  601  and the output power lines  602 , connected to monitoring unit  604 . The monitoring unit  604  includes a digital bus  605  that is connected to a main data bus  606  of the power converter  51 . 
     The power supply control system  60  illustrated in  FIGS. 7 and 8  can be implemented as a third party module  610  that is connected between the electronic power supply  50  and load and the power converter  51 . As shown in  FIG. 8 , an input power cable for the module  610  includes input power lines  611  and data lines  612 , which are wired together with converter power lines  613  and the converter data lines  614 . This allows a direct connection between the electronic power supply  50  and load and the power converter  51 . Within the module  610 , a power bus  615  and data bus  616  are connected to the input power lines  611  and the converter power lines  613 , respectively, and to the input data lines  612  and the converter data lines  614 , respectively. Both the power bus  615  and the data bus  616  are connected to monitoring unit  617   
     The monitoring units  604  and  617  used in the embedded and the external embodiments both include sensors to monitor input and output voltages and currents of the power converter  51  where each sensor is used to measure a single electrical quantity. Each sensor includes a transducer to convert either voltage or current to an appropriate electrical signal and a low-pass filter that outputs a signal to an analog-to-digital converter (ADC). The sensors may be a collection of environmental sensors that each acts as a transducer used to measure one or more of the following environmental parameters: temperature, vibration, humidity, radiation and pressure. Each low pass filter is designed to anti-alias the electrical signals measured from the transducer. 
     The output of each transducer of each sensor is connected to one channel of the ADC. The ADC quantizes all of the sensor values into digital signals and may be connected to a processor  61 , which is itself connected a storage unit  62  (see  FIG. 4 ) to store historical health assessment information, performance metrics and trained models. Health assessments generated by the processor  61  can be displayed using visual indicators or sent to a third party. The storage unit  62  has a predefined and known maximum capacity. 
     In any case, with reference to  FIG. 9 , a method for monitoring a health state of the electronic equipment  40  of the rotorcraft  1  or, more particularly, of the power converter  51  is provided. The method includes capturing data of an operation of the power converter  51  over a sampling range of predefined length (operation  701 ), storing captured data in the storage unit  62  (operation  702 ), deferring a characterization of the stored captured data until a predefined time expires or the storage unit  62  reaches the maximum capacity thereof (operation  703 ) and characterizing a behavior of the operation of the power converter  51  based on an analysis of stored captured data in an event the predefined time has expired or the storage unit  62  has reached the maximum capacity (operation  704 ). 
     In accordance with embodiments, the capturing of the data of operation  701  may include collecting current and voltage samples at the input and the output of the power converter  51  by way of the sensors of the monitoring units  604  and  617  at data collection sampling rates below 1 sample/second. In addition, the sampling range of the predefined length may be any sampling range that encompasses an operational range sufficient for the collection of the data. Also, the characterizing of operation  704  may include characterizing a behavior of input versus output power in the power converter  51  as disclosed in U.S. Pat. No. 8,103,463. In accordance with alternative embodiments, however, it is to be understood that the data collection sampling rates may be synchronous or asynchronous and may be accomplished at higher rates, perhaps exceeding the above-noted 1 sample/second. 
     As described herein, failures of power supplies are usually among the top maintenance drivers for electronic systems. Therefore, detection of an impending failure, prior to loss of functionality, can provide for mission assurance, permit a scheduled versus unscheduled maintenance action, permit increased critical system design flexibility and prevent cascading damage effects due to unmitigated failure of an electronic system. The system and methods described herein achieve these goals while minimizing required processing power and optimizing an amount of data sampled to available storage in the storage unit  62  and thus may be embedded in many new digital power supply systems with little to no design impact. 
     Although the description provided above relates generally to the rotorcraft  1 , it is to be understood that this is merely exemplary and that the features of  FIGS. 4-9  in particular are applicable to other types of aircraft and to other technologies. 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.