Patent Publication Number: US-2022228768-A1

Title: HVAC Motor Automation Control Unit and Adjustment Methods and Apparatus for Same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. Section 119(e) to U.S. Provisional Patent Application No. 63/140,123, filed on Jan. 21, 2021, the entire disclosure of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to local and automated system adjustment devices for motors and other components in heating, ventilating, air-conditioning, and refrigeration (“HVACR”) systems. 
     BACKGROUND OF THE INVENTION 
     HVACR machines are often fitted with one or more variable output, or variable speed, motors (“VS motors”), air valves, water valves, or other signal-controlled HVACR devices where the output is controlled in proportion to a control signal supplied by a local controller, interface, or automation system. 
     A control unit for one of these VS Motors or for other HVACR devices converts the automation control signal into a proportional pulse width modulated (“PWM”) signal. The control unit outputs a PWM signal to the VS Motor or other HVACR device. The VS Motor or other HVACR device returns a proportional signal, pulse rate signal, or other pulse signal that represents device output such as speed, torque, or mass air flow. The output by a motor is commonly expressed as revolutions per minute (“RPM”). Torque is commonly expressed as ounce-feet (“oz-ft.”) or gram-centimeters (“g-cm”). Mass airflow is commonly expressed as pounds per minute (“lbs./min”) or grams per second (“g/sec”), but one of skill in the art commonly simplifies the expression to cubic feet per minute (“CFM”) or cubic meters per second (“CMS”). 
     The control units may also have some form of manual adjustment, such as a rotating knob, increase-decrease buttons, or other form of adjustment mechanism. The manual adjustment can be set permanently or for a certain amount of time. The control units also have some form of display to indicate an adjustment setting and an analog output signal that is proportional to the motor&#39;s RPM. 
     However, HVACR machines often have unique operating conditions. Therefore, there is a need to provide a mechanism for a range of special features for the control units to optimize performance while allowing certain features and parameters to not have to be changed or adjusted in the field. 
     BRIEF SUMMARY OF THE INVENTION 
     For purposes of summarizing the invention, certain aspects, advantages, and novel features of the invention have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any one particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
     According to various embodiments, the invention and disclosure herein uses a digital adjustment profile (“DAP”) in an automation control unit (“ACU”). In one embodiment, a method and apparatus for an ACU for converting an automation control signal to a pulse width modulation (PWM) signal to control the output of a HVACR device such as a VS Motor in an HVACR system is disclosed. 
     In various embodiments, the disclosure and invention provide a mechanism and technique to set values and flags in the ACU that support unique features to the ACU such as a Start Up Counter, RPM PPT (Revolutions Per Minute, Pulse Per Turn) Selection, Manual Adjuster Feedback, Output Limits, Output Ramping, Output Delayed Shutdown, Output Signal Display Scaling, and Multiple Motor RPM Averaging. 
     All the above features in the invention can be configured using a digital device to avoid the HVACR system being adjusted in the field since certain adjustments are set by the equipment manufacturer and should not be adjusted in the field. In various embodiments, using the disclosed invention, equipment manufacturers can develop DAPs to customize the ACU to their unique product needs. 
     In one embodiment, the Output Display Scaling, which is the scaling value displayed by the local display, is scaled between the display values for any two percentage outputs between zero percent and one-hundred percent as defined in the DAP. In place of the traditional zero to one-hundred percent display, the disclosed invention allows customized measurement and display to users of data such as torque, CFM, actual control voltage and/or other engineering units associated with the controlled HVACR device. Measuring and displaying the adjustment in engineering units allows faster and more accurate adjustment. 
     In another embodiment, the Output Limits, which is the minimum allowed output and maximum allowed output signal to the VS Motor or other HVACR device, are defined in the DAP and then loaded into the ACU. When outputting the signal, the disclosed invention outputs a signal no lower than the minimum allowed percent output and no greater than the maximum allowed percent output. The disclosed invention limits the motor output between a high and low limit. Limiting the output allows the motor output to be constrained between high and low output limits to keep the connected VS Motor or other HVACR device operating within a safe range for the HVAC equipment 
     In another embodiment, the Output Delayed Shutdown, which is the amount of time delay before the output signal to the VS Motor or other HVACR device goes to zero, causes the ACU output signal to remain at its current value until a delay timer expires. The disclosed invention allows setting an off delay, which allows the VS Motor or other HVACR device to continue running at the last commanded output for a predefined period after it has been turned off by the building automation system (“BAS”) to optimize energy efficiency of the HVACR equipment. 
     In place of monitoring a single feedback rate from a single VS Motor or other HVACR device, the invention allows monitoring of an adjustable feedback rate of multiple VS Motors or other HVACR devices. 
     In another embodiment the number of startup cycles, or Startup Counter, can be defined in the DAP. This control can be used in manual mode when the BAS is not available. When the BAS becomes available, the Startup Counter allows the control to operate in automation mode automatically without the need to manually switch over at the control. 
     In another embodiment, the RPM Pulse Count Selection, which is the number of pulses per turn of the connected motor output by the connected VS Motor, is defined in the DAP and then loaded into the ACU. The disclosed invention allows a connected VS Motor to have any number of pulses per turn and correctly converts the actual RPMs to the proper analog signal. 
     In another embodiment, the ACU Output Limits changes to a certain pre-programmed rate, known as ramping, to reduce occupant awareness of HVACR system changes. The disclosed invention allows setting the ramping rate, which reduces occupant awareness of changes in airflow and minimizes disturbance due to noise level changes in the controlled environment 
     In another embodiment, for the manual adjuster feedback, the ACU outputs a signal proportional to the manual adjuster. This allows automation systems to read air balance adjustments from the ACU. 
     In another embodiment where the control may be connected to multiple VS Motors or other HVACR devices and the feedback rate from each VS Motor or other HVACR device connects to the control. The control averages the feedback rate values from each VS Motor or other HVACR device and outputs the averaged signal. 
     The disclosed invention allows an option for returning the local adjust to the BAS to simplify commissioning of the building automation system. Often, the BAS is not installed yet when the HVACR equipment is running and controlled by the ACU local adjust in a new facility. This feature allows the BAS to read the local adjust setting to simplify the commissioning of the BAS. 
     Other objects, features, and advantages of the present invention will become apparent upon consideration of the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a diagram of an ACU embodying the present invention. 
         FIG. 2  provides a table of an example digital adjustment profile for the ACU. 
         FIG. 3  illustrates an example embodiment for a Startup Counter Process for a Startup Counter. 
         FIG. 4  illustrates an example embodiment of RPM to Analog Output Process of the present invention. 
         FIG. 5  illustrates an example embodiment of the POT Feedback Output Process of the present invention. 
         FIG. 6  illustrates an example embodiment of an output limits implementation process for the PWM signal output calculation of the present invention. 
         FIG. 7  illustrates an example embodiment of the PWM output calculation process of the present invention when a Ramp function is selected. 
         FIG. 8  illustrates a timing sequence of an output delayed shutdown of the present invention. 
         FIG. 9  illustrates an example embodiment display value scaling process of the present invention as calculated based on the Min Display and Max Display. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following is a detailed description of embodiments to illustrate the principles of the invention. The embodiments are provided to illustrate aspects of the invention, but the invention is not limited to any embodiment. The scope of the invention encompasses numerous alternatives, modifications, and equivalents. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the invention. The scope of the invention is limited only by the claims. 
     While numerous specific details are set forth in the following description to provide a thorough understanding of the invention, the invention may be practiced according to the claims without some or all of these specific details. 
     Various embodiments will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts. References made to particular examples and implementations are for illustrative purposes and are not intended to limit the scope of the claims. 
     ACU Diagram  2000   
       FIG. 1  illustrates an example embodiment of a diagram of ACU  2000  embodying the present invention. ACU  2000  comprises a display  2100 , a microcontroller  2200 , a non-volatile memory  2225 , a digital device connection  2700 , a manually operated adjust  2300 , a signal input  2410 , a second output  2420 , a common connection  2430 , a first output  2510 , a device signal input  2520 , a run output  2530 , a common  2540 , a power input  2600 , and a neutral/common  2610  for electrical return and safety ground. ACU  2000  connects to an HVACR device  2500 . In various example embodiments, HVACR device  2500  can compromise a motor, a variable speed motor, also called a VS Motor, an air valve, a water valve, a temperature controller, or other signal-controlled device. 
     Display  2100  is used to display the RPM status and scaled value of the percentage output to the HVACR device  2500 . Microcontroller  2200  executes various processes using the ACU digital adjustment profile  3000  ( FIG. 2 ) stored in non-volatile memory  2225 . Non-volatile memory  2225  can be either integrated with the microcontroller  2200  or connected to the microcontroller  2200  within ACU  2000 . Non-volatile memory  2225  stores the ACU digital adjustment profile  3000  for access by the microcontroller  2200 . Digital device connection  2700  is used to load the ACU digital adjustment profile  3000  from an external digital device  2710  to non-volatile memory  2225 . 
     Manually operated adjust  2300  can be used to adjust the percent of signal output to the HVACR device  2500 . Common connection  2430  serves as an electrical return path for the connected automation control  2410  and RPM signal  2420 . First output  2510  connects to the HVACR device  2500  to set its output parameter such as its speed. Device signal input  2520  receives a signal from the HAVCR Device  2500  such as a signal from tachometer for a motor. Run output  2530  can be used to turn on HVACR device  2500 . The second output  2420  outputs a signal that can be read by a building automation system (BAS) after the ACU  2000  converts the RPM pulses into an analog signal. 
     Common  2540  serves as an electrical return path for the HVACR device  2500 . Power input  2600  powers the ACU and neutral/common  2610  is an electrical return and safety ground for Power input  2600 . In one embodiment, power input  2600  comprises a 24-volt AC power connection. 
     In an alternative embodiment, first output  2510 , run output  2530 , common  2540  and second device signal input  2521  can be connected to a second HVACR device  2501 . In this alternative embodiment, the display  2100  displays the average parameter status such as average RPMs for HVACR device  2500  and second HVACR device  2501 . 
     ACU Digital Adjustment Profile  3000   
       FIG. 2  provides a table for an example ACU digital adjustment profile  3000  including Startup Counter  3010 , Off Delay  3020 , Pot Feedback  3030 , Pulses Per Turn  3040 , High Out Limit  3050 , Low Out Limit  3060 , Ramp  3070 , Min Display  3080 , Max Display  3090 , RPM Inputs  3100 . 
     The value of Startup Counter  3010  is the number of startup cycles. The startup feature allows operation without a BAS by putting the ACU  2000  into manual mode every time the ACU is turned on until the predefined number of startup cycles is exceeded, after that the ACU will change to automation mode. 
     A value of Off Delay  3020  is the delay time between the automation input signal going to zero and the output to VS Motor or other HVACR device going to zero percent. The ACU  2000  stays on for the duration of the Off Delay  3020  time when the automation signal requests the HVACR device to turn off. 
     Pot Feedback  3030  is when the manually operated adjust  2300  is converted into a voltage signal that is communicated to the BAS, which is controlling many devices in a building, and in one simple example embodiment can be a thermostat. 
     Pulses Per Turn  3040  is the number of pulses per turn from the HVACR device  2500 . 
     High Out Limit  3050  is the maximum output in percent from the control to the HVACR device  2500 . Low Out Limit  3060  is the minimum output in percent from the control to the HVACR device  2500 . 
     When the BAS requests a change, the output will ramp up or down at a rate set by the value of Ramp  3070 , such as five percent per second. The ramping feature reduces building occupant awareness of changes in airflow. 
     A value of Min Display  3080  is the display value when the output signal equals zero percent (0%) of the maximum potential output value. A value of Max Display  3090  is the display value when the output signal equals one-hundred percent (100%) of the maximum potential output value. 
     A value of RPM Inputs  3100  is the number of HVACR devices, which in an example embodiment is one, and in another example embodiment is two. 
     Processes for the ACU  2000   
       FIG. 3  illustrates an example embodiment for Startup Counter Process  4000  for Startup Counter  3010 . Startup Counter Process  4000  begins at step  4010 . At step  4020 , Startup Counter Process  4000  checks if ACU  2000  is in power up mode. If ACU  2000  is in power up mode, Startup Counter Process  4000  continues to step  4030  where Startup Counter Process  4000  checks if the Startup Counter  3010  is zero. If Start-up Counter  3010  is not zero, at step  4040  it is determined whether the Automation Signal, which is sent from the BAS and represents the output the HVACR device should produce, is present. If the Automation Signal is present, the Startup Counter  3010  is decremented at step  4050 . Startup Counter Process  4000  then moves to step  4060  where ACU  2000  is put into Automation Mode. In automation mode the signal to the HVACR device is derived from the BAS. Startup Counter Process  4000  then ends at step  4070 . Returning to step  4020 , if ACU  2000  is not in power up mode Startup Counter Process  4000  then ends at step  4070 . Returning to step  4030 , if the Startup Counter  3010  is zero, Startup Counter Process  4000  ends at step  4070 . Returning to step  4040 , if the Automation Signal is not present, Startup Counter Process  4000  goes to step  4080  where ACU  2000  is put in Manual Mode where the control signal to the HVACR device is derived from the ACU  2000  adjuster setting. Startup Counter Process  4000  then ends at step  4070 . 
       FIG. 4  illustrates an example embodiment of RPM to Analog Output Conversion Process  6000 . RPM to Analog Output Conversion Process  6000  begins at step  6010 . At step  6020 , the pulses from HVACR device  2500  and/or second HVACR device  2501  are counted over a predefined period. Next, at step  6030 , the accumulated pulses are converted to RPM of the respective HVACR device based on the configurable Pulses Per Turn  3040 . At step  6040 , the number of HVACR devices is used to average RPM Inputs  3100 . If there are two HVACR devices, the average RPMs is calculated and used as the output RPM at step  6050 . The output RPM is then converted into an analog signal at step  6090  and output to second output  2420 . RPM to Analog Output Conversion Process  6000  then ends at step  6100 . 
     Going back to step  6040 , if there is only one HVACR device, Step  6060  determines whether HVACR device  2500  or second HVACR device  2501  is connected and used to output the RPM. If HVACR device  2500  is connected, the RPM from HVACR device  2500  is used to calculate the output RPM at step  6070 . At step  6090 , the output RPM is converted into an analog signal and output to second output  2420 . RPM to Analog Output Conversion Process  6000  then ends at step  6100 . 
     Going back to step  6060 , if second HVACR device  2501  is connected, the RPM from HVACR device  2501  is used to calculate the output RPM at step  6080 . The output RPM is converted into an analog signal at step  6090  and output to second output  2420 . RPM to Analog Output Conversion Process  6000  then ends at step  6100 . 
       FIG. 5  illustrates an example embodiment of POT Feedback Output Process  7000  for device signal output  2520  when POT Feedback  3030  is enabled. POT Feedback Output Process  7000  begins at step  7010 . At step  7020 , the manually operated adjust  2300  is read. In manual mode the manually operated adjust  2300  is used to set the ACU output to a certain value. The manually operated adjust  2300  position represents the value set, where the manually operated adjust  2300  can be set between zero percent and one-hundred percent. At step  7030 , the manually operated adjust  2300  position is converted into an analog output signal and output to second output  2420 . POT Feedback Output Process  7000  then ends at  7040 . 
       FIG. 6  illustrates an example embodiment of the output limits implementation process  9000  for the PWM signal output calculation. The output limits implementation process  9000  begins at step  9010 . At step  9020 , the control signal is read into Output Variable. Output variable is the ACU internal variable that is processed by applying limits or rate of change, and the result is sent to the run output  2530 . 
     Output limits implementation process  9000  then moves to step  9030  where the Output Variable between 0% and 100% is scaled between the High Output Limit  3050  and Low Output Limit  3060  to determine the scaled output. Output limits implementation process  9000  then moves to step  9040  where the scaled output from step  9030  is converted to a PWM signal and outputted to first output  2510 . Output limits implementation process  9000  then ends at step  9050 . 
       FIG. 7  illustrates an example embodiment of the PWM output calculation process  10000  when the Ramp  3070  function is selected. The PWM output calculation process  10000  starts at step  10010 . At step  10020 , the control signal is read. Next, at step  10030 , the signal is compared to Signal_out. Signal_out is generated within the ACU  2000 , and is incremented or decremented when the ramp timer expires. Ramp  3070  defines the rate of the Signal_out ramp, and is a repetitive signal, starting then turning off at the predefined time and then repeating. 
     If signal is equal to Signal_out, then PWM output calculation process  10000  moves to step  10090  where the Signal_out is converted to PWM and outputted to first output  2510 . PWM output calculation process  10000  then ends at step  10100 . Returning to step  10030 , where PWM output calculation process  10000  checks if signal from the BAS is equal to Signal_out. If it is not equal, then PWM output calculation process  10000  moves to step  10040  where it is determined if the ramp timer has expired. If the ramp timer has not expired, PWM output calculation process  10000  moves to step  10090  where the Signal_out is converted to a PWM signal and outputted to first output  2510 . PWM output calculation process  10000  then ends at step  10100 . 
     Going back to step  10040 , where PWM output calculation process  10000  checks if the ramp timer has expired, if the ramp timer has expired, PWM output calculation process  10000  moves to step  10050  to start the ramp timer. At step  10060 , the signal is compared to Signal_out. If signal is less than Signal_out, then PWM output calculation process  10000  moves to step  10080  where Signal_out is decremented. PWM output calculation process  10000  then moves to step  10090  where the Signal_out is converted to PWM and outputted to first output  2510 . PWM output calculation process  10000  then ends at step  10100 . 
     Going back to step  10060 , where signal is compared to Signal_out, if signal is larger than Signal_out, then PWM output calculation process  10000  moves to step  10070  where Signal_out is incremented. PWM output calculation process  10000  then moves to step  10090  where the Signal_out is converted to PWM and outputted to first output  2510 . PWM output calculation process  10000  then ends at step  10100 . 
       FIG. 8  illustrates the timing sequence  11000  of the output delayed shutdown, which is the time delay between the request to shutdown and the actual shutdown. There are two possible conditions. For condition one, the input signal goes from the current value to zero. For condition two, the input signal goes from the current value to a non-zero new value. 
     In condition one, the shutdown starts at  11010  where a decrease in input signal is detected. The output signal remains at its current level at  11040 . Once the input signal reaches zero at  11020  the Off Delay Timer  11030  is started, and when the Off Delay Timer  11030  expires the output signal is turned off at  11050 . 
     In condition two, the input signal again starts going low at  11010 . However, the output signal remains at level at  11070  until the input signal reaches the new value at  11060 . Then the output signal is set to the new value at  11090 . 
       FIG. 9  illustrates an example embodiment display value scaling process  12000  according to the Min Display  3080  and Max Display  3090 . The display value scaling process  12000  begins at step  12010 . At step  12020 , the automation signal is read into Output Variable. Display value scaling process  12000  then moves to step  12030  where the Output Variable between 0% and 100% is scaled between Min Display  3080  and Max Display  3090 . The process moves to step  12040  where the Scaled Display Value from  12030  is sent to display  2100 . Display value scaling process  12000  then ends at step  12050 . 
     The disclosed embodiments are illustrative, not restrictive. While specific configurations have been described, it is understood that the present invention can be applied to a wide variety of applications. There are many alternative ways to implement the invention.