System controller for a variable speed heating, ventilation, and air conditioning system

Abstract

A control system for a heating, ventilation, and air conditioning (HVAC) system is provided. The system controller includes a processor configured to receive an indoor temperature measurement or estimate and an indoor temperature setpoint and, while operating a compressor motor in a line operation mode or a drive operation mode, control a speed of at least one of an indoor fan motor or an outdoor fan motor based on the indoor temperature measurement to cause an indoor temperature to converge to the indoor temperature setpoint.

Description

FIELD

[0001] The field of the disclosure relates generally to a system controller, and specifically to a system controller for a variable capacity air conditioning or heat pump system.BACKGROUND

[0002] Heating, ventilation, and air conditioning (HVAC) systems generally include electric motors, which may be used to rotate a compressor or fans of the HVAC system. At least some known induction motors are fixed speed motors that operate most efficiently at line frequency power. Such motors exhibit uncontrolled acceleration during startup. Further, at low load conditions, such motors operate less efficiently. Alternatively, some induction motors may be driven with a variable speed motor controller to adapt motor speed to a load level. Such configurations may be limited by power factor, electromagnetic interference, and electrical losses.

[0003] A drive circuit for certain motors enables efficient operation at both high and low load conditions. For example, a motor operating a compressor in an HVAC system may experience high load conditions during peak temperatures and low load conditions during milder temperatures. The drive circuit operates the motor using an inverter under low load conditions, and operates the motor using line frequency power under high load conditions.BRIEF DESCRIPTION

[0004] In one aspect, a control system for an HVAC system is provided. The control system includes a processor configured to receive an indoor temperature measurement or estimate and an indoor temperature setpoint and, while operating a compressor motor in a line operation mode or a drive operation mode, control a speed of at least one of an indoor fan motor or an outdoor fan motor based on the indoor temperature measurement to cause an indoor temperature to converge to the indoor temperature setpoint.

[0005] In another aspect, a method for controlling an HVAC system is provided. The method includes receiving an indoor temperature measurement or estimate and an indoor temperature setpoint and, while operating a compressor motor in a line operation mode or a drive operation mode, controlling a speed of at least one of an indoor fan motor or an outdoor fan motor based on the indoor temperature measurement to cause an indoor temperature to converge to the indoor temperature setpoint.

[0006] In another aspect, an HVAC system is provided. The HVAC system includes a compressor motor, an indoor fan motor, an outdoor fan motor, and a control system coupled in communication with the compressor motor, the indoor fan motor, and the outdoor fan motor. The control system includes a processor configured to receive an indoor temperature measurement or estimate and an indoor temperature setpoint and, while operating the compressor motor in a line operation mode or a drive operation mode, control a speed of at least one of the indoor fan motor or the outdoor fan motor based on the indoor temperature measurement to cause an indoor temperature to converge to the indoor temperature setpoint.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1A is a block diagram of an HVAC system in accordance with the present disclosure;

[0008] FIG. 1B is a block diagram of another HVAC system in accordance with the present disclosure;

[0009] FIG. 2 is a graph illustrating indoor and outdoor temperature during a first example period;

[0010] FIG. 3 is a graph illustrating motor speed and airflow during the first example period shown in FIG. 2

[0011] FIG. 4 is a graph illustrating indoor and outdoor temperature during a second example transition period;

[0012] FIG. 5 is a graph illustrating motor speed and airflow during the second example period shown in FIG. 3

[0013] FIG. 6 is a flowchart illustrating an example method for controlling an HVAC system.DETAILED DESCRIPTION

[0014] HVAC systems generally include a compressor, an indoor fan (e.g., a blower or evaporator fan) and an outdoor fan (e.g., a condenser fan), which are each turned by a respective electric motor. In some cases, the compressor motor utilizes a hybrid drive where the electric motor is supplied power through an inverter under low load conditions and supplied line frequency power under high load conditions. While this configuration enables the compressor speed to be varied based on demand, in certain cases, the compressor can only operate at certain discrete speed values and / or up to certain speed thresholds. In situations where a cooling demand (e.g., based on an outdoor temperature) gradually changes over time, which requires a gradual change in cooling capacity to maintain a constant indoor temperature, an inability of the compressor motor to operate in certain ranges of speed values may limit an ability of HVAC system to precisely match a system capacity to the current cooling demand.

[0015] The embodiments described herein include a control system for an HVAC system. The controller system may include, for example, a system controller, one or more local controllers (e.g.,. motor or fan controllers), a thermostat, or any combination thereof. In an example embodiment, the control system is configured to communicate with and control electric motors of the HVAC system, including a compressor motor, an indoor fan motor, and an outdoor fan motor. The control system is configured to receive an indoor temperature measurement or estimate and an indoor temperature setpoint. The indoor temperature setpoint may be received, for example, as a thermostat command.

[0016] In the example embodiment, the compressor motor operates at one or more discrete modes of operation. For example, the compressor motor may be a hybrid drive motor that is configured to operate at a fixed speed while operating in a line operation mode and a variable speed while operating in a drive operation mode. While operating the compressor motor in a line operation mode or a drive operation mode, the control system controls a speed of at least one of an indoor fan motor or an outdoor fan motor based on the indoor temperature measurement or estimate to cause an indoor temperature to converge to the indoor temperature setpoint. Thus, the system controller is capable of varying a system capacity of the HVAC system to meet a cooling demand at a particular moment without needing to adjust a speed of the compressor motor. This is advantageous when the compressor motor is operating at a fixed speed while in the line operation mode. While operating the compressor motor in the drive operation mode, the speed of the compressor motor can also be varied to achieve the demanded indoor temperature.

[0017] While the systems and methods described herein are generally described as being applied in an HVAC system, it should be appreciated that these systems and methods can also be applied to other types of climate control, heating, and / or cooling systems that include a compressor motor and at least one fan motor.

[0018] FIGS. 1A and 1B are block diagrams illustrating example embodiments of an HVAC system 100. In the example embodiment, HVAC system 100 includes a control system 102, a compressor motor 104, an indoor fan motor 106, an outdoor fan motor 108, sensors 110, and a thermostat 112. In various example implementations, control system 102 may include a system controller, a local motor controller of compressor motor 104, indoor fan motor 106, and / or outdoor fan motor 108, thermostat 112, and / or some combination thereof. Control system 102 includes at least one processor and at least one memory device configured to store instructions that, when executed by the at least one processor, cause the at least one processor to perform the functions of control system 102 described herein. Control system 102 is coupled in communication with compressor motor 104, indoor fan motor 106, outdoor fan motor 108, and thermostat 112. In some embodiments, as shown in FIG. 1A, control system 102 is further coupled in communication with sensors 110. Additionally, or alternatively, as shown in FIG. 1B, sensors 110 may be coupled in communication with thermostat 112, which in some cases may provide data received from sensors 110 to control system 102.

[0019] In the exemplary embodiment, compressor motor 104 is coupled to a compressor and is configured to operate at a plurality of speed values. For example, in some embodiments, compressor motor 104 is configured to operate in one of two different modes of operation including a line operation mode and a drive operation mode. In the line operation mode, windings of compressor motor 104 are supplied power directly from a line source at line frequency (e.g., 60 hertz), and compressor motor 104 operates at a fixed speed, which is generally the maximum speed of compressor motor 104. In the drive operation mode, the windings are supplied power from an inverter at a variable frequency, enabling compressor motor 104 to operate at a variable speed. In some implementations, when operating in the drive operation mode, the speed of compressor motor 104 is variable between a plurality of predefined frequency values. Thus, compressor motor can operate at a plurality of different speed settings (e.g., one speed value setting in line operation mode and one or more speed settings while in the drive operation mode).

[0020] Indoor fan motor 106 is coupled to an indoor fan, such as an evaporator fan and / or blower fan. Outdoor fan motor 108 is coupled to an outdoor fan such as a condenser fan. In some embodiments, indoor fan motor 106 and / or outdoor fan motor 108 are configured to operate at a variable speed. Indoor fan motor 106 and / or outdoor fan motor 108 can be controlled based on various types of setpoints such as, for example, speed, torque, or, particularly in the case of indoor fan motor 106, airflow.

[0021] Control system 102 is configured to receive an indoor temperature measurement or estimate. For example, sensors 110 may include at least one indoor temperature sensor located in an interior space of a structure and, in some cases, may include additional sensors (e.g., an outdoor temperature sensor located outside of the structure), and control system 102 may receive data from these sensors 110. Control system may further receive an indoor temperature setpoint. For example, control system 102 may receive a thermostat command from thermostat 112, based on which system controller determines the indoor temperature demand.

[0022] Control system 102 is further configured to periodically compute, based on the indoor temperature measurement or estimate, one or more motor speed values (e.g., a speed for compressor motor 104, indoor fan motor 106, and / or outdoor fan motor 108) that achieve a system capacity sufficient to satisfy an indoor temperature demand. Control system 102 is further configured to, while operating compressor motor 104 at a in the line operation mode or the drive operation mode, control a speed of indoor fan motor 106 and / or outdoor fan motor 108 based on the indoor temperature measurement or estimate to cause an indoor temperature to converge to the indoor temperature setpoint. In certain embodiments, a characterization process is used to identify certain setpoints or combinations of setpoints for indoor fan motor 106 and / or outdoor fan motor 108, such as for speed, torque, airflow, and / or other motor settings, that result in a certain system capacity or ability to achieve a certain temperature demand based on current measurements. This characterization is stored in a memory of control system 102, for example, as a formula (e.g., a linear or polynomial regression) or lookup table, which can subsequently be used by control system 102 to identify appropriate setpoints for indoor fan motor 106 and / or outdoor fan motor 108 based on the demanded indoor temperature.

[0023] By controlling and varying a speed of indoor fan motor 106 and / or outdoor fan motor 108 while compressor motor 104 is operating at a certain constant speed setting (e.g., while operating in the line operation mode), control system 102 is capable of varying the system capacity of HVAC system 100 without needing to adjust a speed of compressor motor 104. This capability is particularly advantageous while operating in the line operation mode when compressor motor 104 is operated at a fixed (i.e., line) frequency. Additionally, controlling and varying a speed of indoor fan motor 106 and / or outdoor fan motor 108 enables the system capacity to be controlled while compressor motor 104 is transitioning between modes or speed settings. For example, control system 102 may control indoor fan motor 106 and / or outdoor fan motor 108 to maintain a constant system capacity or to ramp the system capacity at a predefined rate.

[0024] In some embodiments, control system 102 is configured to select a mode and / or a speed setting at which to operate the compressor motor based on sensor data received from sensors 110. This sensor data may include, for example, an indoor or outdoor temperature measurement or estimate, a compressor power consumption, a compressor input current, an inverter anticipated phase current, an inverter anticipated thermal margin, an indoor temperature slope, an outdoor temperature slope, a system pressure, or a time spent (e.g., historically) at each mode of operation or speed setting. Additionally, or alternatively, in certain embodiments, control system 102 selects to control compressor motor 104 to operate in the line operation mode or in the drive operation mode based on at least one of compressor motor 104, indoor fan motor 106, or the outdoor fan motor 108 meeting a predefined threshold (e.g., meeting or exceeding threshold speed) or another threshold event occurring (e.g., exceeding a temperature threshold or threshold difference between the measured or estimated indoor temperature and the temperature setpoint).

[0025] FIG. 2 is a graph 200 illustrating indoor and outdoor temperature during a first example transition in which compressor motor 104 transitions from operating in the line operation mode to operating in the drive operation mode due to a decreasing cooling demand. FIG. 3 is a graph 300 illustrating speeds of compressor motor 104 and outdoor fan motor 108 and an indoor airflow produced by indoor fan motor 106 during this transition.

[0026] Referring to FIG. 2, graph 200 includes a horizontal axis 202 representing time expressed in minutes over a first time period, a first vertical axis 204 representing dry bulb temperature expressed in degrees Fahrenheit, and a second vertical axis 206 representing wet bulb temperature expressed in degrees Fahrenheit. Graph 200 further includes an outdoor temperature curve 208 representing an outdoor dry bulb temperature, an indoor dry bulb temperature curve 210 representing an indoor dry bulb temperature, and an indoor wet bulb temperature curve 212 representing an indoor wet bulb temperature.

[0027] Referring to FIG. 3, graph 300 includes a horizontal axis 302 representing time expressed in minutes, which coincides with the first time period illustrated by horizontal axis 302 in graph 200, a first vertical axis 304 representing a motor speed in rotations per minute, and a second vertical axis 306 representing airflow expressed in standard cubic feet per minute. Graph 300 further includes a compressor motor speed curve 308 representing a speed of compressor motor 104, an outdoor fan speed curve 310 representing a speed of outdoor fan motor 108, and an indoor airflow curve 312 representing an airflow (e.g., through a blower or other predefined point within HVAC system 100) generated by indoor fan motor 106.

[0028] Referring back to FIG. 2, an outdoor temperature (indicated by outdoor temperature curve 208) decreases over the first time period from about 95 degrees Fahrenheit to about 85 degrees Fahrenheit. During this change in temperature, it is desirable to maintain a constant indoor dry bulb temperature (indicated by indoor dry bulb temperature curve 210) of, in this example, 80 degrees Fahrenheit and an indoor wet bulb temperature (indicated by indoor wet bult temperature curve 212) of, in this example, 67 degrees Fahrenheit. To maintain a constant indoor temperature while outdoor temperature gradually changes, a system capacity needs to gradually be adjusted. In other words, while the outdoor temperature of a home may change, HVAC system modulates its capacity so that the indoor temperature remains substantially the same.

[0029] Referring back to FIG. 3, control system 102 controls compressor motor 104, indoor fan motor 106, and outdoor fan motor 108 to achieve the specific system capacity needed to maintain the indoor air temperature. As indicated by compressor motor speed curve 308, compressor motor 104 operates at a first discrete value when operating in the line operation mode and a second discrete value when operating in the drive operation mode. For this reason, transitioning compressor motor 104 from operating in the line operation mode to operating in the drive operation mode alone does not provide the gradual change in system capacity needed to maintain a constant temperature in this example. To provide a gradual change in system capacity, a speed of outdoor fan motor 108 and an airflow provided by indoor fan motor 106 are also varied, as indicated by outdoor fan speed curve 310 and indoor airflow curve 312, to provide the required system capacity at a given moment in time.

[0030] FIG. 4 is a graph 400 illustrating indoor and outdoor temperature during a second example transition while compressor motor 104 operates in the drive operation mode and can operate at a variable frequency. FIG. 5 is a graph 500 illustrating speeds of compressor motor 104 and outdoor fan motor 108 and an indoor airflow produced by indoor fan motor 106 during this transition.

[0031] Referring to FIG. 4, graph 400 includes a horizontal axis 402 representing time expressed in minutes over a second time period, a first vertical axis 404 representing dry bulb temperature expressed in degrees Fahrenheit, and a second vertical axis 406 representing wet bulb temperature expressed in degrees Fahrenheit. Graph 400 further includes an outdoor temperature curve 408 representing an outdoor dry bulb temperature, an indoor dry bulb temperature curve 410 representing an indoor dry bulb temperature, and an indoor wet bult temperature curve 412 representing an indoor wet bulb temperature.

[0032] Referring to FIG. 5, graph 500 includes a horizontal axis 502 representing time expressed in minutes, which coincides with the second time period illustrated by horizontal axis 502 in graph 500, a first vertical axis 504 representing a motor speed in rotations per minute, and a second vertical axis 506 representing airflow expressed in standard cubic feet per minute. Graph 500 further includes a compressor speed curve 508 representing a speed of compressor motor 104, an outdoor fan speed curve 510 representing a speed of outdoor fan motor 108, and an indoor airflow curve 512 representing an airflow (e.g., through a blower or other predefined point within HVAC system 100) generated by indoor fan motor 106.

[0033] Referring back to FIG. 4, an outdoor temperature (indicated by outdoor temperature curve 408) decreases over the second time period from about 85 degrees Fahrenheit to about 67 degrees Fahrenheit. During this change in temperature, it is desirable to maintain a constant indoor dry bulb temperature (indicated by indoor dry bulb temperature curve 410) of, in this example, 80 degrees Fahrenheit and an indoor wet bulb temperature (indicated by indoor wet bult temperature curve 412) of, in this example, 67 degrees Fahrenheit. To maintain a constant indoor temperature while outdoor temperature gradually changes, a system capacity needs to gradually be adjusted. In other words, while the outdoor temperature of a home may change, HVAC system modulates its capacity so that the indoor temperature remains substantially the same.

[0034] Referring back to FIG. 5, control system 102 controls compressor motor 104, indoor fan motor 106, and outdoor fan motor 108 to achieve the specific system capacity needed to maintain the indoor air temperature. As indicated by compressor motor speed curve 508, when in the drive operation mode, compressor motor 104 operates at a variable speed that is controlled to achieve the required system capacity. To help or provide further degrees of control in providing a gradual change in system capacity, an airflow provided by indoor fan motor 106 is also varied, as indicated by indoor airflow curve 512, to provide the required system capacity at a given moment in time. While a speed of outdoor fan motor 108 is not varied in this example as illustrated by outdoor fan speed curve 510, in some example implementations, the speed of outdoor fan motor 108 may also be varied.

[0035] FIG. 6 is a flowchart illustrating an example method 600 for controlling an HVAC system 100. Control system 102 receives 602 an indoor temperature measurement (e.g., from sensors 110) or estimate and an indoor temperature setpoint (e.g., from thermostat 112). While operating compressor motor 104 in a line operation mode or a drive operation mode, control system 102 controls 604 a speed of at least one of indoor fan motor 106 or outdoor fan motor 108 based on the indoor temperature measurement or estimate to cause an indoor temperature to converge to the indoor temperature setpoint.

[0036] In certain embodiments, while operating in the drive operation mode, control system 102 controls a speed of compressor motor 104 within a predefined range to cause the indoor temperature to converge to the indoor temperature setpoint.

[0037] In some embodiments, while operating in the line operation mode, control system 102 operates compressor motor 104 at a constant speed.

[0038] In certain embodiments, control system 102 controls compressor motor 104 to operate in the line operation mode or the drive operation mode based on at least one of compressor motor 104, indoor fan motor 106, or the outdoor fan motor 108 meeting a predefined threshold (e.g., a threshold speed).

[0039] In some embodiments, during a transition of compressor motor 104 between the line operation mode and the drive operation mode, control system 102 varies a speed of at least one of indoor fan motor 106 or outdoor fan motor 108 to cause the indoor temperature to converge to the indoor temperature setpoint.

[0040] In certain embodiments, control system 102 controls compressor motor 104 to operate in the line operation mode or the drive operation mode based on sensor data.

[0041] In some such embodiments, the sensor data includes one or more of an outdoor temperature measurement, a compressor power consumption, a compressor input current, an inverter anticipated phase current, an inverter anticipated thermal margin, an indoor temperature slope, an outdoor temperature slope, a system pressure, or a time spent at each mode of operation.

[0042] In certain embodiments, control system 102 determine the indoor temperature setpoint based on a thermostat command.

[0043] In some embodiments, control system 102 controls the speed of indoor fan motor 106 based on a target airflow to cause the indoor temperature to converge to the indoor temperature setpoint.

[0044] In certain embodiments, control system 102 controls at least one of indoor fan motor 106 or outdoor fan motor 108 to operate at a variable speed while operating the compressor motor at a constant speed.

[0045] In some embodiments, control system 102 controls the speed of at least one of the indoor fan motor or the outdoor fan motor based on the indoor temperature measurement to minimize disturbances in a system capacity of the HVAC system.

[0046] An example technical effect of the methods, systems, and apparatus described herein includes at least one of: (a) enabling a system capacity of an HVAC system to be varied while operating a compressor motor of the HVAC system in a discrete or fixed-speed mode of operation by varying a speed of one or more fan motors of the HVAC system to achieve a target system capacity; and (b) enabling a system capacity of an HVAC system to be varied while operating a compressor motor of the HVAC system in a variable-speed mode of operation by varying a speed of the compressor motor and one or more fan motors of the HVAC system to achieve a target system capacity.

[0047] Some embodiments involve the use of one or more electronic or computing devices (e.g., for controlling operation of a drive circuit and / or individual components thereof). Such devices typically include a processor, processing device, or controller, such as a general purpose central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, a reduced instruction set computer (RISC) processor, an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), a field programmable gate array (FPGA), a digital signal processing (DSP) device, and / or any other circuit or processing device capable of executing the functions described herein. The methods described herein may be encoded as executable instructions embodied in a computer readable medium, including, without limitation, a storage device and / or a memory device. Such instructions, when executed by a processing device, cause the processing device to perform at least a portion of the methods described herein. The above examples are exemplary only, and thus are not intended to limit in any way the definition and / or meaning of the terms: processor, processing device, and controller.

[0048] In the embodiments described herein, memory may include, but is not limited to, a computer-readable medium, such as a random-access memory (RAM), and a computer-readable non-volatile medium, such as flash memory. Alternatively, a floppy disk, a compact disc – read only memory (CD-ROM), a magneto-optical disk (MOD), and / or a digital versatile disc (DVD) may also be used. Also, in the embodiments described herein, additional input channels may be, but are not limited to, computer peripherals associated with an operator interface such as a mouse and a keyboard. Alternatively, other computer peripherals may also be used that may include, for example, but not be limited to, a scanner. Furthermore, in the example embodiment, additional output channels may include, but not be limited to, an operator interface monitor.

[0049] As used herein, the terms “software” and “firmware” are interchangeable and include any computer program stored in memory for execution by a processor, including RAM memory, ROM memory, EPROM memory, EEPROM memory, and non-volatile RAM (NVRAM) memory. The above memory types are examples only and are thus not limiting as to the types of memory usable for storage of a computer program.

[0050] As used herein, an element or step recited in the singular and preceded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “example implementation” or “one implementation” of the present disclosure are not intended to be interpreted as excluding the existence of additional implementations that also incorporate the recited features.

[0051] The systems and methods described herein are not limited to the specific embodiments described herein, but rather, components of the systems and / or steps of the methods may be utilized independently and separately from other components and / or steps described herein.

[0052] This written description uses examples to provide details on the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure 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.

Claims

1. A control system for a heating, ventilation, and air conditioning (HVAC) system, the control system comprising a processor configured to:receive an indoor temperature measurement or estimate and an indoor temperature setpoint; andwhile operating a compressor motor in a line operation mode or a drive operation mode, control a speed of at least one of an indoor fan motor or an outdoor fan motor based on the indoor temperature measurement or estimate to cause an indoor temperature to converge to the indoor temperature setpoint.

2. The control system of claim 1, wherein the processor is further configured to, while operating in the drive operation mode, control a speed of the compressor motor within a predefined range to cause the indoor temperature to converge to the indoor temperature setpoint.

3. The control system of claim 1, wherein the processor is further configured to, while operating in the line operation mode, operate the compressor motor at a constant speed.

4. The control system of claim 1, wherein the processor is further configured to control the compressor motor to operate in the line operation mode or the drive operation mode based on at least one of the compressor motor, the indoor fan motor, or the outdoor fan motor meeting a predefined threshold.

5. The control system of claim 1, wherein the processor is further configured to, during a transition of the compressor motor between the line operation mode and the drive operation mode, vary a speed of at least one of the indoor fan motor or the outdoor fan motor to cause the indoor temperature to converge to the indoor temperature setpoint.

6. The control system of claim 1, wherein the processor is further configured to control the compressor motor to operate in the line operation mode or the drive operation mode based on sensor data.

7. The control system of claim 6, wherein the sensor data includes one or more of an outdoor temperature measurement, a compressor power consumption, a compressor input current, an inverter anticipated phase current, an inverter anticipated thermal margin, an indoor temperature slope, an outdoor temperature slope, a system pressure, or a time spent at each mode of operation.

8. The control system of claim 1, wherein the processor is further configured to determine the indoor temperature setpoint based on a thermostat command.

9. The control system of claim 1, wherein the processor is further configured to control the speed of the indoor fan motor based on a target airflow to cause the indoor temperature to converge to the indoor temperature setpoint.

10. The control system of claim 1, wherein the processor is further configured to control at least one of the indoor fan motor or the outdoor fan motor to operate at a variable speed while operating the compressor motor at a constant speed.

11. The control system of claim 1, wherein the processor is further configured to control the speed of at least one of the indoor fan motor or the outdoor fan motor based on the indoor temperature measurement to minimize disturbances in a system capacity of the HVAC system.

12. A method for controlling a heating, ventilation, and air conditioning (HVAC) system, the method comprising:receiving an indoor temperature measurement or estimate and an indoor temperature setpoint; andwhile operating a compressor motor in a line operation mode or a drive operation mode, controlling a speed of at least one of an indoor fan motor or an outdoor fan motor based on the indoor temperature measurement or estimate to cause an indoor temperature to converge to the indoor temperature setpoint.

13. The method of claim 12, further comprising, while operating in the drive operation mode, controlling a speed of the compressor motor within a predefined range to cause the indoor temperature to converge to the indoor temperature setpoint.

14. The method of claim 12, further comprising, while operating in the line operation mode, operating the compressor motor at a constant speed.

15. The method of claim 12, further comprising controlling the compressor motor to operate in the line operation mode or the drive operation mode based on at least one of the compressor motor, the indoor fan motor, or the outdoor fan motor meeting a predefined threshold.

16. The method of claim 12, further comprising, during a transition of the compressor motor between the line operation mode and the drive operation mode, varying a speed of at least one of the indoor fan motor or the outdoor fan motor to cause the indoor temperature to converge to the indoor temperature setpoint.

17. The method of claim 12, further comprising controlling the compressor motor to operate in the line operation mode or the drive operation mode based on sensor data.

18. The method of claim 12, further comprising determining the indoor temperature setpoint based on a thermostat command.

19. The method of claim 12, further comprising controlling at least one of the indoor fan motor or the outdoor fan motor to operate at a variable speed while operating the compressor motor at a constant speed.

20. A heating, ventilation, and air conditioning (HVAC) system comprising:a compressor motor;an indoor fan motor;an outdoor fan motor; anda control system coupled in communication with the compressor motor, the indoor fan motor, and the outdoor fan motor, the control system comprising a processor configured to:receive an indoor temperature measurement or estimate and an indoor temperature setpoint; andwhile operating the compressor motor in a line operation mode or a drive operation mode, control a speed of at least one of the indoor fan motor or the outdoor fan motor based on the indoor temperature measurement or estimate to cause an indoor temperature to converge to the indoor temperature setpoint.

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