Patent Publication Number: US-2023151990-A1

Title: Systems and methods for controlling a motor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. Pat. Application No. 15/618846, filed on Jun. 9, 2017, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     The embodiments described herein relate generally to motors, and more particularly, to systems and methods for controlling a motor in a heating, ventilation, air conditioning (HVAC) system. 
     Motors used in HVAC and fluid circulation systems often must be programmed to operate according to the specific needs of their systems and may need to be replaced when they do not operate properly or fail. Typically, the motors are programmed using a specialized motor programming computer by an Original Equipment Manufacturers (OEM) at a motor manufacturing facility, at the point of sale, or at an assembly plant. 
     OEMs that utilize configurable/intelligent motors configure each motor to meet the requirements of the specific product and the expected application. The functionality of the OEM system is derived from a combination of the motor’s configuration and the operation of an HVAC system controller. For example, signal definitions/functions associated with a system controller wiring harness are determined by the motor’s configuration. With each replacement configurable/intelligent motor needing to be ordered with the specific OEM system configuration, returning a failed system to operation may be a time consuming and expensive process. 
     BRIEF DESCRIPTION 
     In one aspect, a heating, ventilation, and air conditioning (HVAC) system is provided. The HVAC system includes a second motor that has replaced a first motor, a system controller previously coupled to and configured to transmit instructions for control of the first motor according to a previous configuration, and an interface module communicatively coupled between the system controller and the second motor when the second motor has replaced the first motor. The interface module is configured to receive, via a communication interface, after the second motor has replaced the first motor, a first input signal from a thermostat of the HVAC system and a second input signal from the system controller, and compare an aggregate signal of the first and second input signals with stored reference information to determine an intended operating mode, from a plurality of operating modes, of the HVAC system, The interface module is also configured to determine an operating parameter at which to operate the second motor based on the determined operating mode, transmit a control signal to the second motor to control the second motor according to the operating parameter, and provide a motor output feedback signal to the system controller based on operation of the second motor according to the operating parameter. 
     In another aspect, an interface module for controlling a second motor in a heating, ventilation, and air conditioning (HVAC) system is provided. The interface module includes a memory, a communication interface, and a processor communicatively coupled to the memory and the communication interface. The processor is programmed to receive, via the communication interface, after the second motor has replaced the first motor, a first input signal from a thermostat of the HVAC system and a second input signal from the system controller, and compare an aggregate signal of the first and second input signals with stored reference information to determine an intended operating mode, from a plurality of operating modes, of the HVAC system. The processor is also programmed to determine an operating parameter at which to operate the second motor based on the determined operating mode, transmit a control signal to the second motor to control the second motor according to the operating parameter, and provide a motor output feedback signal to the system controller based on operation of the second motor according to the operating parameter. 
     In one aspect, an interface module configured to control a motor in a heating, ventilation, and air conditioning (HVAC) system is provided. The interface module is configured to determine an operating mode selected from a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device, determine a motor operating parameter at which to operate the motor based on the determined operating mode, and control the motor in accordance with the motor operating parameter. 
     In another aspect, a method controlling a motor in a heating, ventilation, and air conditioning (HVAC) system using an interface module is provided. The method includes determining an operating mode selected from a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device, determining a motor operating parameter at which to operate the motor based on the determined operating mode, and controlling the motor in accordance with the motor operating parameter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an exemplary HVAC system that includes an interface module for controlling a motor. 
         FIG.  2    is a flowchart of an exemplary method of controlling a motor using the interface module shown in  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    is a schematic diagram of a heating, ventilation, and air conditioning (HVAC) system  100  that includes an interface module  102  and a retrofit motor  104 . HVAC system  100  also includes a thermostat  106  and a system controller  108 . Interface module  102  is coupled to and configured to receive signals from both thermostat  106  and system controller  108 . Further, interface module  102  is coupled to and configured to transmit signals to motor  104 . 
     In the exemplary embodiment, motor  104  is an electronically commutated motor (ECM), which may also be referred to as a brushless direct current (DC) motor. Motor  104  is utilized as a fan and/or blower motor in HVAC system  100 . Alternatively, motor  104  may be implemented in any other application including, but not limited to, a fluid (e.g., water, air, etc.) moving system, a clean room filtering system, a fan filter unit, a variable air volume system, a refrigeration system, a furnace system, and/or an air conditioning system. In the exemplary embodiment, HVAC system  100  is retrofit to include motor  104  that replaces an existing ECM or permanent split capacitor (PSC) motor (hereinafter referred to as “replaced motor”, not shown). 
     Thermostat  106  is configured to control a mode in which HVAC system  100  is operating, for example, a cooling mode, a heating mode, or a fan only mode, and/or at a first stage or at a second stage. Thus, in the exemplary embodiment, thermostat  106  includes plurality of thermostat leads  110  associated with one or more of a cooling output, a heating output, a fan output, a first stage output, and a second stage output. However, thermostat  106  is not limited to these outputs and may include any number of outputs that enables thermostat  106  to function as described herein. Thermostat  106  generates at least one thermostat signal that is transmitted to at least one of interface module  102  and system controller  108 . 
     System controller  108  includes a system controller wiring harness  112  that was originally coupled to and configured to transmit instructions to the replaced motor. When interface module  102  is provided during the replacement process, system controller wiring harness  112  is coupled to and configured to communicate with interface module  102 . For example, system controller  108  relays signals generated by thermostat  106  to interface module  102 . More specifically, system controller  108  processes the thermostat signal and generates instructions for operating motor  104  that are provided to interface module  102 . System controller  108  may also communicate with other input/output devices, such as humidity control systems, gas burner controls, gas ignition systems, other motors, safety systems, service systems, and/or combustion blowers. Accordingly, system controller  108  generates operating instructions for motor  104  based on signals received from thermostat  106 , as well as signals received from alternative devices coupled to system controller  108 , such as safety systems, ambient sensors, gas ignition systems, and other HVAC system components. 
     Interface module  102  receives signals from at least one of thermostat  106  and system controller  108 . Based on the received signals, interface module  102  provides motor  104  with control signals. More specifically, interface module  102  receives signals from thermostat leads  110 , as well as from system controller  108  via system controller wire harness  112 , and is configured to provide motor  104  with a signal that selects a desired motor control profile. 
     In the exemplary embodiment, interface module  102  includes components mounted to a printed circuit board. More specifically, in the exemplary embodiment, interface module  102  includes a processing device  114 , a memory device  116 , a user interface  118 , and a communication interface  120 . 
     The term processing device, as used herein, refers to central processing units, microprocessors, microcontrollers, reduced instruction set circuits (RISC), application specific integrated circuits (ASIC), logic circuits, and any other circuit or processor capable of executing the functions described herein. 
     It should be noted that the embodiments described herein are not limited to any particular processor for performing the processing tasks of the invention. The term “processor,” as that term is used herein, is intended to denote any machine capable of performing the calculations, or computations, necessary to perform the tasks of the invention. The term “processor” also is intended to denote any machine that is capable of accepting a structured input and of processing the input in accordance with prescribed rules to produce an output. It should also be noted that the phrase “configured to” as used herein means that the processor is equipped with a combination of hardware and software for performing the tasks described herein, as will be understood by those skilled in the art. 
     Communication interface  120  may include an RS-485 connector, a digital serial interface (DSI) connector, a control wire reception terminal, and/or any other type of interface that allows a user, thermostat  106 , and/or system controller  108  to provide a control signal to interface module  102 . For example, the control signal may include a 0-10 volts direct current (VDC) control signal, a 0-5 VDC control signal, a 4-20 milliampere (mA) control signal, and/or any other type of control signal that allows interface module  102  to function as described herein. 
     In the exemplary embodiment, interface module  102  also includes memory device  116 . Memory device  116  may be included within processing device  114 , or may be coupled to processing device  114 . In the exemplary embodiment, memory device  116  stores a plurality of different communications protocols. For example, processing device  114  may access the communications protocols stored in memory device  116  in order to translate a signal received from a user via communication interface  120  into a format that may be transmitted to motor  104 . More specifically, processing device  114  may receive a signal sent using an Ethernet protocol, in which motor  104  may not be compatible. Processing device  114  translates the received signal to a communication suitable to be transmitted to motor  104 . 
     Interface module  102  includes a user interface  118  that enables user-interaction with interface module  102  and enables interface module  102  to provide feedback with regards to its operation. User interface  118  facilitates configuration (i.e., setup) of interface module  102 . Original ECM functionality that is being replicated by interface module  102  is enabled via user interface  118 . User interface  118  further enables selection of operational values such as “ON” delay times, “OFF” delay times, duty cycle values, etc. 
     User interface  118  includes a plurality of buttons/switches and a display. The display provides information relating to the operation of interface module  102  including, but not limited to, system control signals status, thermostat signals status, system operating mode, motor torque percent, and/or delay activity. The display is also configured to provide diagnostic (e.g., system health) and self-test information. 
     Alternatively, interface module  102  may be implemented as a “black box” void of any buttons/switches or display. In this implementation, interface module  102  communicates with an intelligent wireless device (e.g., smartphone, tablet, PDA, etc., not shown) using wireless communication (e.g., Wi-Fi, Bluetooth, RFID, etc.) via communication interface  120 . The wireless device runs/executes an application that provides user interface  118  and feedback functions. 
     Interface module  102  is configured to determine an operating mode of HVAC system  100  (heat, cool, etc.). When the configuration of the replaced motor and the operations of system controller  108  are unknown, thermostat signals and the motor control signals from system controller  108  enable determination of the operating mode of HVAC system  100 . Interface module  102  continuously or periodically monitors an aggregate signal of the system controller signals and the thermostat signals, and compares the resulting aggregate signal with stored reference information to determine the operating mode of the system. 
     In the exemplary embodiment, to acquire the information necessary for determining the system operating mode, interface module  102  is configured to “learn” the HVAC system’s operation by implementing a learning algorithm that, over time, enables interface module  102  to recognize and store as a reference the system and thermostat signal combinations and timing that are used to resolve the operating mode of HVAC system  100 . In some embodiments, interface module  102  is configured to discriminate between discrete and variable speed motor control as well as recognize a single stage thermostat that is paired with a dual stage system. 
     In another embodiment, the information necessary for determining the system operating mode is acquired by teaching interface module  102  to recognize system and thermostat signal combinations. While exercising HVAC system  100  throughout its different modes of operation, the installer manually triggers interface module  102  to capture a “snapshot” of the available inputs for each mode of operation. Interface module  102  correlates each mode of operation with a respective snapshot to identify the system operating modes. A snapshot is a unique combination of states of individual system and thermostat signals, i.e., inputs. 
     In yet another embodiment, interface module  102  acquires the information necessary for determining the system operating mode via manual configuration of interface module  102  with the appropriate information by a technician or installer of motor  104 . 
     Interface module  102  is configured to implement “ON” delays and “OFF” delays in HVAC systems that allocate this functionality to motor  104 . More specifically, interface module  102  facilitates enabling/disabling and/or selecting time values for ON delays and OFF delays for the appropriate system operating modes in order to complete/replicate the HVAC system performance. 
     Interface module  102  is configured to provide feedback to be utilized by HVAC system  100  to satisfy expectations of system controller  108 . Specifically, interface module  102  facilitates enabling/disabling and/or selecting one of a plurality of available motor output signal types. This feature is realized by pairing interface module  102  with a known retrofit/replacement motor that provides a fundamental motor output signal that interface module  102  modifies based on its configuration and passes on to system controller  108 . 
     Interface module  102  is further configured to control motor  104 . In operating motor  104 , interface module  102  provides a control signal to motor  104  based on signals received from thermostat  106  and system controller  108 . In the exemplary embodiment, motor  104  is a “communicating” ECM motor and interface module  102  controls motor  104  using commands. For example, the physical layer of interface module  102  may include serial, controller area network (CAN), wireless, bus, and/or any other standard communications interface/protocol. Interface module  102  provides a single control signal that includes an industry recognized, standard PWM signal to drive motor  104 . A duty cycle of the control signal corresponds to a percent of full torque that may be generated by motor  104 . 
     In an alternative embodiment, where motor  104  may need unique programming, such as field programming, for each system, interface module  102  is configured to provide a 0 to 10 Vdc control signal to motor  104 . 
     Interface module  102  in combination with motor  104  is configured to affect airflow that assures safe operation of HVAC system  100 . Interface module  102  maintains (e.g., in non-volatile memory) a duty cycle value for each operating mode of HVAC system  100 . Initially, default values are used to operate motor  104 . During installation, a service technician verifies the airflow in all operating modes to ensure that the temperature rise of fossil fuel heating systems and the CFM per ton of cooling meet OEM specifications. Interface module  102  provides a user interface  118  for making adjustments to the stored duty cycle values as determined by the technician. 
       FIG.  2    is a flowchart of an exemplary method  200  of controlling a motor in a HVAC system using interface module  102  (shown in  FIG.  1   ). 
     Initially, method  200  includes determining  202  an operating mode of a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device. In some embodiments, the first device may be a thermostat and the second device may be a system controller of the HVAC system. Method  200  also includes determining  204  a motor operating parameter at which to control the motor based on the determined operating mode. Method  200  further includes operating  206  the motor in accordance with the motor operating parameter. 
     In one embodiment, method  200  may include continuously monitoring an aggregate signal of the system controller signals and the thermostat signals, and comparing the resulting aggregate signal with stored reference information to determine the operating mode of the HVAC system. 
     In another embodiment, to determine the operating mode of the HVAC system, method  200  may include implementing, by the interface module, an algorithm that, over time, recognizes and stores as a reference, the first and second device signal combinations and timing. 
     In another embodiment, wherein to operate the motor, method  200  may include transmitting a pulse width modulation (PWM) signal that represents the motor operating parameter, wherein a duty cycle of the PWM signal corresponds to a percent of full torque that may be generated by motor. 
     In another embodiment, method  200  may include receiving, via a user interface of the interface module, operational values input by a user, the operational values including at least one of ON delay times, OFF delay times, and duty cycle values, and implementing the operational values prior to operating the motor. 
     The embodiments described herein provide an interface module and methods of controlling a motor. The embodiments facilitate determining an operating mode of a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device, determining a motor operating parameter at which to operate the motor based on the determined operating mode, and controlling the motor in accordance with the motor operating parameter. The interface module facilitates replacing or retrofitting a failed motor in a HVAC system with a readily available, stock, retrofit/replacement motor. The interface module provides a cost-effective solution to interfacing between HVAC system controllers, thermostats and replacement motors. Further, the interface module facilitates returning a failed HVAC system to operation quickly and efficiently (e.g., in one service call). 
     Exemplary embodiments of the interface module and methods of controlling a motor are described above in detail. The interface module and methods are not limited to the specific embodiments described herein, but rather, components of the interface module and/or steps of the method may be utilized independently and separately from other components and/or steps described herein. For example, the control system and methods may also be used in combination with other motor systems and methods, and are not limited to practice with only the HVAC system as described herein. Rather, the exemplary embodiments can be implemented and utilized in connection with many other system applications or other support. 
     A technical effect of the system described herein includes at least one of: (a) determining an operating mode of a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device; (b) determining a motor operating parameter at which to operate the motor based on the determined operating mode; (c) controlling the motor in accordance with the motor operating parameter; (d) replacing or retrofitting a failed motor in a HVAC system with a readily available, stock, retrofit/replacement motor; (e) provides a cost-effective solution to interfacing between HVAC system controllers, thermostats and replacement motors; and (f) facilitates returning a failed HVAC system to operation quickly and efficiently. 
     Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any layers or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.