Abstract:
An elevator system includes an elevator car disposed in and arranged to move along a hoistway. A linear propulsion system of the elevator system is constructed and arranged to propel the elevator car, and includes a plurality of primary coils engaged to and distributed along the hoistway generally defined by a stationary structure. A wireless power transfer system of the elevator system is configured to inductively transfer power to the elevator car. The wireless power transfer system includes a secondary coil mounted to the elevator car and is configured to be induced with electromotive forces by the primary coils and output power for use by the elevator car. A communication system of the elevator system is configured to utilize the secondary coil and the plurality of primary coils to exchange a communication data signal.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 62/212,798, filed Sep. 1, 2015, the entire contents of which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to elevator systems, and more particularly to a communication system integrated with wireless power transfer system of the elevator system. 
         [0003]    Traveling electrical cables are traditionally used to power and to communicate with non-stationary elevator cars of an elevator system. The moving cable based solution is disadvantageous for long and fast motions, due to its mechanical and electrical limitations. Furthermore, for communication between the controller and the car, channels separate from the power line used. For position sensing of the car, conventionally, exclusive sensors such as resolver and, rotary position sensors on, for example, the motor shaft are used in combination with magnetic vane sensors mounted on the elevator car. In cases where the elevator car is propelled by linear motors, Hall Effect sensors mounted on linear motor primary structures may be used. Such solutions are not suitable for very high rise elevators. Also, conventional wireless communication solutions have many challenges in implementation, robustness, and other challenges. 
       SUMMARY 
       [0004]    An elevator system according to one, non-limiting, embodiment of the present disclosure includes an elevator car disposed in and constructed and arranged to move along a hoistway; a linear propulsion system constructed and arranged to propel the elevator car, the linear propulsion system including a plurality of primary coils engaged to and distributed along the hoistway generally defined by a stationary structure; a wireless power transfer system configured to inductively transfer power to the elevator car, the wireless power transfer system including a secondary coil mounted to the elevator car and configured to be induced with electromotive forces by the plurality of primary coils and output power for use by the elevator car; and a communication system configured to utilize the secondary coil and the plurality of primary coils to exchange a communication data signal. 
         [0005]    Additionally to the foregoing embodiment, the communication system includes a first communication device carried by the elevator car and configured to receive communication data and output a communication data signal to the secondary coil. 
         [0006]    In the alternative or additionally thereto, in the foregoing embodiment, the first communication device is an intelligent signal modulator. 
         [0007]    In the alternative or additionally thereto, in the foregoing embodiment, the communication system includes a second communication device supported by the stationary structure and in communication with a controller of the linear propulsion system configured to selectively control energization the plurality of primary coils. 
         [0008]    In the alternative or additionally thereto, in the foregoing embodiment, the second communication device is a demodulator. 
         [0009]    In the alternative or additionally thereto, in the foregoing embodiment, the communication system includes a position sensor supported by the elevator car and configured to output a position signal to the first communication device. 
         [0010]    In the alternative or additionally thereto, in the foregoing embodiment, the position sensor is an accelerometer. 
         [0011]    In the alternative or additionally thereto, in the foregoing embodiment, the communication system includes a sensor supported by the elevator car and configured to output a signal to the first communication device, and wherein the sensor is at least one of a moisture sensor, a pressure sensor, a sound sensor, a light sensor and an occupancy sensor. 
         [0012]    In the alternative or additionally thereto, in the foregoing embodiment, the plurality of primary coils are configured to transmit power to the secondary coil when a primary coil of the plurality of primary coils is adjacent to the secondary coil and is selectively energized. 
         [0013]    In the alternative or additionally thereto, in the foregoing embodiment, the linear propulsion system includes a control system configured to select and energize the plurality of primary coils, the control system including a plurality of switches with each one of the plurality of switches being associated with a respective one of the plurality of primary coils, and wherein the plurality of switches selectively close to energize a selected one of the plurality of resonant primary coils associated with a location of the elevator car. 
         [0014]    In the alternative or additionally thereto, in the foregoing embodiment, the communication system is configured to send the communication signal through a selected one of the plurality of switches when closed. 
         [0015]    In the alternative or additionally thereto, in the foregoing embodiment, the control system includes a controller configured to control the plurality of switches for selective energization of the plurality of resonant primary coils based on a location of the elevator car. 
         [0016]    In the alternative or additionally thereto, in the foregoing embodiment, the communication system includes an intelligent signal modulator carried by the elevator car and configured to receive communication data and output the communication data signal to the secondary coil, and a demodulator supported by the stationary structure and in communication with the controller of the linear propulsion system. 
         [0017]    In the alternative or additionally thereto, in the foregoing embodiment, the communication system includes a position sensor supported by the elevator car and configured to output a position signal to the first communication device. 
         [0018]    In the alternative or additionally thereto, in the foregoing embodiment, the communication data includes at least one of elevator car position, safety-related information, fault detection, health monitoring, and information exchange. 
         [0019]    In the alternative or additionally thereto, in the foregoing embodiment, the power transfer system include a power converter carried by the elevator car and configured to receive the communication data signal from the first communication device. 
         [0020]    In the alternative or additionally thereto, in the foregoing embodiment, the power converter provides AC power to AC loads of the elevator car. 
         [0021]    A wireless communication system for exchanging communication data with an elevator car constructed to move in a hoistway, the wireless communication system according to another, non-limiting, embodiment includes an intelligent signal modulator mounted to the elevator car and configured to receive an elevator car communication data signal; a secondary coil mounted to the elevator car and configured to induce a current for elevator car power and receive the communication data signal from the intelligent signal modulator; a plurality of primary coils distributed along the hoistway; and configured to transmit power to the secondary coil when a primary coil of the plurality of primary coils is proximate to the secondary coil and is selectively energized, and to receive the communication data signal from the second coil; and a demodulator configured to receive the communication data signal from the plurality of primary coils. 
         [0022]    Additionally to the foregoing embodiment, the demodulator outputs the communication data signal to a controller. 
         [0023]    In the alternative or additionally thereto, in the foregoing embodiment, the intelligent signal modulator outputs the communication data signal to a power converter in the elevator car that is configured to output the communication data signal to the secondary coil. 
         [0024]    In the alternative or additionally thereto, in the foregoing embodiment, the wireless communication system includes a plurality of communication modules with each one of the communication modules associated with a respective one of the plurality of primary coils, and wherein the plurality of communication modules are configured to selectively receive the communication data signal from the respective primary coil and output the communication data signal to the demodulator. 
         [0025]    The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. However, it should be understood that the following description and drawings are intended to be exemplary in nature and non-limiting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiments. The drawings that accompany the detailed description can be briefly described as follows: 
           [0027]      FIG. 1  depicts a multicar elevator system in an exemplary embodiment; 
           [0028]      FIG. 2  is a top down view of a car and portions of a linear propulsion system in an exemplary embodiment; 
           [0029]      FIG. 3  is a schematic of the linear propulsion system; and 
           [0030]      FIG. 4  is a schematic of a wireless power transfer system combined with a communication system of the elevator system. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]      FIG. 1  depicts a self-propelled or ropeless elevator system  20  in an exemplary embodiment that may be used in a structure or building  22  having multiple levels or floors  24 . Elevator system  20  includes a hoistway  26  having boundaries defined by the structure  22  and at least one car  28  adapted to travel in the hoistway  26 . The hoistway  26  may include, for example, three lanes  30 ,  32 ,  34  each extending along a respective centerline  35  with any number of cars  28  traveling in any one lane and in any number of travel directions. For example and as illustrated, the cars  28  in lanes  30 ,  34 , may travel in an up direction and the cars  28  in lane  32  may travel in a down direction along the centerline  35 . Moreover, the cars  28  may travel horizontally along a centerline  35  within upper and lower transfer stations  36 ,  38 . 
         [0032]    Above the top floor  24  may be the upper transfer station  36  that facilitates horizontal motion to elevator cars  28  for moving the cars between lanes  30 ,  32 ,  34 . Below the first floor  24  may be the lower transfer station  38  that facilitates horizontal motion to elevator cars  28  for moving the cars between lanes  30 ,  32 ,  34 . It is understood that the upper and lower transfer stations  36 ,  38  may be respectively located at the top and first floors  24  rather than above and below the top and first floors, or may be located at any intermediate floor. Yet further, the elevator system  20  may include one or more intermediate transfer stations (not illustrated) located vertically between and similar to the upper and lower transfer stations  36 ,  38 . 
         [0033]    Referring to  FIGS. 1 through 3 , cars  28  are propelled using a linear propulsion system  40  having at least one, fixed, primary portion  42  (e.g., two illustrated in  FIG. 2  mounted on opposite sides of the car  28 ), moving secondary portions  44  (e.g., two illustrated in  FIG. 2  mounted on opposite sides of the car  28 ), and a control system  46  (see  FIG. 4 ). The primary portion  42  includes a plurality of windings or coils  48  mounted at one or both sides of the lanes  30 ,  32 ,  34  in the hoistway  26 . Each secondary portion  44  may include two rows of opposing permanent magnets  50 A,  50 B mounted to the car  28 . Primary portion  42  is supplied with drive signals from the control system  46  to generate a magnetic flux that imparts a force on the secondary portions  44  to control movement of the cars  28  in their respective lanes  30 ,  32 ,  34  (e.g., moving up, down, or holding still). The plurality of coils  48  of the primary portion  42  may generally be located between and spaced from the opposing rows of permanent magnets  50 A,  50 B. It is contemplated and understood that any number of secondary portions  44  may be mounted to the car  28 , and any number of primary portions  42  may be associated with the secondary portions  44  in any number of configurations. 
         [0034]    Referring to  FIG. 3 , the control system  46  may include power sources  52 , drives  54 , buses  56  and a controller  58 . The power sources  52  are electrically coupled to the drives  54  via the buses  56 . In one non-limiting example, the power sources  52  may be direct current (DC) or alternating current (AC) power sources. DC power sources  52  may be implemented using storage devices (e.g., batteries, capacitors), and may be active devices that condition power from another source (e.g., rectifiers). AC power sources may be implemented using a power grid or an alternator. The drives  54  may receive DC power from the buses  56  and may provide drive excitation to the primary portions  42  of the linear propulsion system  40 . Each drive  54  may be a converter that converts DC power from bus  56  to a multiphase (e.g., three phase) drive excitation provided to a respective section of the primary portions  42 . The primary portion  42  is divided into a plurality of modules or sections, with each section associated with a respective drive  54 . 
         [0035]    The controller  58  provides control signals to each of the drives  54  to control generation of the drive signals. Controller  58  may use pulse width modulation (PWM) control signals to control generation of the drive signals by drives  54 . Controller  58  may be implemented using a digital signal processor-based device programmed to generate the control signals. The controller  58  may also be part of an elevator control system or elevator management system. Elements of the control system  46  may be implemented in a single, integrated module, and/or be distributed along the hoistway  26 . 
         [0036]    Referring to  FIG. 4 , a wireless power transfer system  60  of the elevator system  20  may be used to power loads  61  in or on the elevator car  28 . The power transfer system  60  may be an integral part of the control system  46  thereby sharing various components such as the controller  58 , buses  56 , power source  52  and portions of the linear propulsion system  40  such as the primary portion  42  and other components. Alternatively, the wireless power transfer system  60  may generally be independent of the control system  46  and/or linear propulsion system  40 . The power loads  61  may be alternating current (AC) loads such as a fan motor, utilizing a traditional power frequency, for example, about sixty (60) Hz. Alternatively, or in addition thereto, the loads  61  may include direct current (DC) loads such as on-car controllers, relays, LED lights, and a holding brake. 
         [0037]    The wireless power transfer system  60  may include a power source  62 , a converter  64  that may be a high frequency converter, at least one conductor  66  for transferring power (e.g., high frequency power) from the converter  64 , a plurality of switches  68 , and a plurality of resonant primary coils  70  that may generally be the primary portion  42 . Each one of the resonant primary coils  70  are associated with a respective one of the plurality of switches  68 . The power transfer system  60  may further include a controller  72  that may be part of the controller  58 . The controller  72  may be configured to selectively and sequentially place and/or maintain the switches  68  in an off position (i.e., circuit open) and/or in an on position (i.e., circuit closed). The power source  62  may be the power source  52  and may further be of a DC or of an AC type with any frequency (i.e. low or high). 
         [0038]    The converter  64  may be configured to convert the power outputted by the power source  62  to a high frequency power for the controlled and sequential energization of the resonant primary coils  70  by transmitting the high frequency power through the conductors  66 . More specifically, if the power source  62  is a DC power source, the converter  64  may convert the DC power to an AC power and at a prescribed high frequency. If the power source  62  is an AC power source with, for example, a low frequency such as 60 Hz, the converter  64  may increase the frequency to a desired high frequency value. For the present disclosure, a desired high frequency may fall within a range of about 1 kHz to 1 MHz, and preferably within a range of about 50 kHz to 500 kHz. It is further contemplated and understood that for transferring data over power, the band width of the communication (i.e., the amount of data that can be transferred per second) is dictated, at least in-part, by this frequency. 
         [0039]    The wireless power transfer system  60  may further include components generally in or carried by the elevator car  28 . Such components may include a resonant secondary coil  74  configured to induce a current when an energized resonant primary coil  70  is proximate thereto, a resonant component  76  that may be active and/or passive, a power converter  78  to regulate voltage from the resonant secondary coil, and an energy storage device  80  that may be utilized to store power for the AC or DC loads  61 . The resonant secondary coil  74  may be induced with an electro-motive force (EMF) or voltage when the coil is proximate to an energized resonant primary coil  74 . The resonant primary coil  70  is energized when the respective switch  68  is closed based on the proximity of the elevator car  28  and resonant secondary coil  74 . 
         [0040]    Each switch  68  may be controlled by the controller  72  over pathways  82  that may be hard-wired or wireless. Alternatively, or some combination thereof, the switches  68  may be smart switches each including a sensor  84  that senses a parameter indicative of the proximity of the resonant secondary coil  74 . For example, the sensor  84  may be an inductance sensor configured to sense a change of inductance across the associated resonant primary coil  70  indicative of a proximate location of the resonant secondary coil  74 . Alternatively, the sensor  84  may be a capacitance sensor configured to sense a change of capacitance across the associated resonant primary coil  70  indicative of a proximate location of the resonant secondary coil  74 . In another embodiment, the controller  72  may assume limited control and the switches  68  may still be smart switches. For example, the controller  72  may control the duration that a given switch remains closed; however, the switches are ‘smart’ in the sense that they may be configured to move to the closed or open position based on its local intelligence with or without the controller instruction to do so. 
         [0041]    The AC voltage induced across the resonant secondary coil  74  is generally at the high frequency of the resonant primary coil  70 . The ability to energize the resonant primary coils  70  with the high frequency power (i.e., as oppose to low frequency) may optimize the efficiency of induced power transfer from the resonant primary coil  70  to the resonant secondary coil  74 . Moreover, the high frequency power generally facilitates the reduction in size of many system components such as the coils  70 ,  74 , the resonant component  76  and the converter  78  amongst others. Reducing the size of components improves packaging of the system and may reduce elevator car  28  weight. 
         [0042]    The resonant component  76  may be passive with a fixed value or with an actively controlled variable value. As a passive resonant component  76 , the component is generally capacitive in nature (e.g., a capacitor) and capable of operating with AC power. As an active resonant component  76 , the component  76  is configured to mitigate the effects of a weak or variable coupling factor (i.e., varies when the resonant secondary coil  74  passes between resonant primary coils  70 ). That is, the resonant component  76  may be configured or operated in such a fashion that it can control the output current and voltage, and hence, power from the resonant secondary coil  74 . 
         [0043]    The power converter  78  is configured to process power at a high frequency, received from the resonant component  76 . The converter  78  may process the high frequency power to a desirable frequency power (e.g., low power frequency of about sixty (60) Hz or other) that is compatible with AC loads  61  in the elevator car  28 . The converter  78  may further function to convert the high frequency power to DC power, which is then stored in the energy storage device  80 . An example of an energy storage device may be a type of battery. 
         [0044]    The elevator system  20  may further include a communication system  90  that may generally share the primary coils  48  of the primary portions  42  with the linear propulsion system  40  and the power transfer system  60 , and share the secondary coil  74  with the power transfer system  60 . The communication system  90  may further include a first communication device  92  that may be in direct communication with or integral to the controller  72 , a plurality of communication modules  94  with each module generally associated with a respective switch  68  and/or primary coil  70 , a second communication device  96  generally supported by and/or positioned within the elevator car  28 , an elevator car position sensor  98  and an elevator car data link  100 . 
         [0045]    The communication device  92  may, as one non-limiting example, be a demodulator, and may generally be in and supported by the stationary structure  22 . The communication device  96  may, as one non-limiting example, be an intelligent signal modulator, and may generally be in and/or supported by the elevator car  28 . The modulation may be accomplished by switching a capacitive load before the input of the converter  78 , or by switching a resistive load at the output of converter  78 . The switching sequence may employ an encoding scheme such as differential bi-phase encoding. The transmitted data signal is received by the communication device  92  by sensing voltage, current or impedance at the primary coils. The received signal may be demodulated by the communication device  92  or by the communication modules  94  to extract the transmitted data by the communication device  96 . The communication modules  94  generally operate in tandem with the control of the switches  68 . More specifically, the modules  94  are configured to communicate between the primary coils  48  of the primary portions  42  such that the switches  68  are activated based upon the proximity of the elevator car to the primary coils. Furthermore, the modules  94  may be configured to each other and the communication device  92 , such that data received by various primary coils  48  at different moving or stationary positions of the elevator car  28  may be combined and collectively utilized. 
         [0046]    The communication device  96  is configured to receive data input from the position sensor  98  (e.g., accelerometer) for sending elevator car position data to the controller  72 . Further, the communication device  96  may receive any other type of data from the elevator car via the communication link  100  and any variety of other sensors. Such data may include or is otherwise associated with fault detection, safety-related information, health monitoring, ride comfort, pressure, temperature, moisture, occupancy, and other data. 
         [0047]    In operation, the wireless communication link between modules  94  in the hoistway  26  and the elevator car  28  may be established simultaneously during the transfer of wireless power or the communication can be carried out in a time sliced or sequential manner with the wireless power transfer. For the first case, the communication signal is super-imposed over the power signal by applying various modulation techniques, for example, load modulation or impedance modulation. For the latter case, suitable analog and digital modulation techniques may be used for the data transfer. 
         [0048]    The wireless power transfer system  60  is thus utilized as a communication channel with multi-functionality. Other benefits may include position sensing of the elevator car  28  that may be carried out to improve safety reliability of the elevator operation, and a communication channel that may provide a robust link for exchanging data with the car and to improve the quality, reliability, and safety of the elevator system  20 . Furthermore, the communication device  90  may be integrated with other sensors for any variety of uses. 
         [0049]    While the present disclosure is described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the present disclosure. In addition, various modifications may be applied to adapt the teachings of the present disclosure to particular situations, applications, and/or materials, without departing from the essential scope thereof. The present disclosure is thus not limited to the particular examples disclosed herein, but includes all embodiments falling within the scope of the appended claims.