Patent Application
20230204211
The embodiments herein generally relate to furnaces, and, more specifically, to a system and method for controlling blower motors of furnaces.
Furnaces utilize a blower motor to drive a blower and an inducer motor to drive an induced draft blower. Conventionally, the blower motor and the inducer motor are controlled by separate electronic motor controllers that are physically integrated with each motor.
According to one embodiment, a furnace is provided. The furnace including: a blower assembly compartment; a blower assembly located within the blower assembly compartment; a blower motor located within the blower assembly compartment, the blower motor operably connected to a fan of the blower assembly; an induced draft blower; an inducer motor operably connected to the induced draft blower; and a dual motor controller located within the blower assembly compartment, the dual motor controller being configured to independently control at least one of a torque or a speed of the blower motor and the inducer motor.
In addition to one or more of the features described above, or as an alternative, further embodiments may include a controller housing, wherein the dual motor controller is located in the controller housing.
In addition to one or more of the features described above, or as an alternative, further embodiments may include a blower housing configured to house a fan of the blower assembly, wherein the controller housing is attached to the blower housing.
In addition to one or more of the features described above, or as an alternative, further embodiments may include a furnace control board electrically connected to the dual motor controller; and a power source wire electrically connecting the furnace control board to a single power source.
In addition to one or more of the features described above, or as an alternative, further embodiments may include a combustion compartment, the induced draft blower and the inducer motor being located in the combustion compartment.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the blower assembly compartment is thermally separated from the combustion compartment.
According to another embodiment, a method of assembling a furnace is provided. The method including: installing a blower motor within a blower assembly; installing the blower assembly within a blower assembly compartment of the furnace; installing an inducer motor in an induced draft blower; installing the induced draft blower in a combustion compartment of the furnace; and installing a dual motor controller within the blower assembly compartment, the dual motor controller being configured to independently control at least one of a torque or a speed of the blower motor and the inducer motor.
In addition to one or more of the features described above, or as an alternative, further embodiments may include installing the dual motor controller in a controller housing.
In addition to one or more of the features described above, or as an alternative, further embodiments may include attaching the controller housing to a blower housing configured to house a fan of the blower assembly.
In addition to one or more of the features described above, or as an alternative, further embodiments may include electrically connecting a furnace control board to the dual motor controller; and electrically connecting the furnace control board to a single power source using a power source wire.
In addition to one or more of the features described above, or as an alternative, further embodiments may include operably connecting the blower motor to a fan of the blower assembly.
In addition to one or more of the features described above, or as an alternative, further embodiments may include operably connecting the inducer motor to the induced draft blower.
According to another embodiment, a method of operating a furnace is provided. The furnace comprising a blower motor, an inducer motor, and a dual motor controller, the blower motor being operably connected to a fan, the inducer motor being operably connected to an induced draft blower, the method comprising: independently controlling, via the dual motor controller, at least one of a torque or a speed of the blower motor and the inducer motor, wherein the dual motor controller and the blower motor are located within a blower assembly compartment.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the inducer motor is located in a combustion compartment, the combustion compartment being thermally separated from the blower assembly compartment.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the dual motor controller is electrically connected to a furnace control board, a power source wire electrically connects the furnace control board to a single power source.
Technical effects of embodiments of the present disclosure include utilizing a single electronic controller to control a blower motor for a blower and an inducer motor for an induced draft blower of a furnace.
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. It should be understood, however, that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
Conventional modulating furnaces and some ultra-low NOx furnaces use a variable speed blower motor and a variable speed inducer motor. Each of these motors typically has its own variable frequency drive (VFD) to independently control the speed or torque of their respective motors. This increases the number of components that need to be sourced and maintained, it also increases the number of interconnecting wires and cost of the system in general.
The embodiments disclosed herein seek to utilize a dual motor controller that is implemented using two integrated power modules sized appropriately for the blower motor and the inducer motor. Also, the dual motor controller disclosed herein may have a single DC link bank that is shared between the two power modules. A single power supply provides all the auxiliary voltages for the VFD, single diode rectifier, PFC circuits, EMI filter, and input protections.
The dual motor controller may be a microcontroller that is implemented as a single micro controller or dual microcontrollers. This architecture helps reduces the cost of the integrated solution. This architecture also helps with the removal of a thermal protection in the inducer motor, by declaring the dual controller as protective control and moving the electronics away from the combustion compartment of the furnace.
The structure 10 includes an HVAC system 20 disposed and configured to control environmental conditions within the interior 12. The HVAC system 20 includes one or more of an outdoor unit 21 and an indoor unit 22. The outdoor unit 21 is disposed at the exterior 13 of the structural body 11 and the indoor unit 22 is disposed in the interior 12.
As shown in
As shown in
Refrigeration lines 23 are provided to connect the outdoor unit 21 with the indoor unit 22 and ducts 24 are provided throughout the interior 12 such that heated or cooled air can be transported from the indoor unit 22 to the various areas in the interior 12. It is understood that while
In some cases, the components of the outdoor unit 21 and the indoor unit 22 may be included in a single unit that can be disposed at the exterior 13 of the structural body 11 or in the interior 12. For example, the components of the indoor unit 22 may be included in the outdoor unit 21 and disposed at the exterior 13. Conversely, the components of the outdoor unit 21 may be included in the indoor unit 22 and disposed in the interior 12. Still other embodiments exist in which the components of the outdoor unit 21 and indoor unit 22 are included in a single device which is partially disposed at the exterior 13 and partially disposed in the interior 12 (e.g., a window air-conditioning unit or wall air conditioning unit).
The HVAC system 20 may further include one or more sensors 510, such as temperature sensors, that are distributed throughout the interior 12 and possibly at the exterior 13. The sensors 510 are in wireless or wired communication with the thermostat 500, a further discussed herein. The thermostat 500 is generally accessible to an individual and is configured to control various operations of the outdoor unit 21 and indoor unit 22 to maintain desired environmental conditions in the interior 12 in accordance with at least readings of the one or more sensors 510 and with commands input by a user.
The thermostat 500 may have the capability to establish and maintain wireless connectivity over one or more networks (e.g., Wi-Fi, Bluetooth, Z-Wave, Zigbee, etc.). The thermostat 500 can therefore be connected to a homeowner's Wi-Fi network and the Internet. This allows the thermostat 500 to have additional features and capabilities including, but not limited to, being remotely controllable by a user using a portable computing device (e.g., a mobile phone, a tablet, a laptop, etc.).
Referring now to
The furnace 300 may include a burner assembly 312, a burner box 314, a combustion air vent 316, and a gas valve 318. The burner assembly 312 may be located within the burner box 314 and may be supplied with air through the combustion air vent 316. Fuel (e.g., combustible gas) may be supplied to the burner assembly 312 through the gas valve 318, and the fuel may be ignited by an igniter assembly (not shown). The gas valve 318 may comprise a conventional solenoid-operated two-stage gas valve. The gas valve 318 for the two-stage furnace may have a closed state, a high open state associated with the operation of furnace 300 at its high firing rate, and a low open state associated with the operation of furnace 300 at its low firing rate.
The furnace 300 may include a heat exchanger assembly, which may include a plurality of heat exchangers including a primary or non-condensing heat exchanger 320 and a secondary or condensing heat exchanger 324. The furnace 300 may further include a condensate collector box 326, an exhaust vent (not shown), an induced draft blower 330, and an inducer motor 332 operably connected to the induced draft blower 330. The inducer motor 332, one of a plurality of motors in the furnace 300, may drive the induced draft blower 330. The inducer motor 332 may be operable or configured to drive the induced draft blower 330. Gases produced by combustion within the burner box 314 may flow through the plurality of heat exchangers, the condensate collector box 326 and may then be vented to the atmosphere through the exhaust vent (not shown). The flow of these gases, alternatively referred to as combustion gases, may be maintained by the induced draft blower 330.
The two-stage furnace 300 may further include a thermostat 500, a plurality of pressure switches including a low pressure switch 342 and a high pressure switch 344, and a plurality of pressure tubes including a first pressure tube 346 and a second pressure tube 348. Excess air levels in the furnace 300 may be kept within an acceptable lower limit in part by the low pressure switch 342. Excess air levels in the furnace 300 may be kept within an acceptable higher limit in part by the high pressure switch 344. To sense pressure at the inlet of the primary heat exchanger 320, the plurality of pressure switches may be connected to the burner box 314 through a pressure tube 346. To sense pressure at the outlet of the secondary heat exchanger 324, the plurality of pressure switches 342 and 344 may be connected to collector box 326 through the pressure tube 348.
The furnace 300 may further include a blower assembly 350 and a blower motor 352 operably connected to a fan 359 of the blower assembly 350. The blower motor 352, another of the plurality of motors in the furnace 300, may drive the fan 359. The blower motor 352 may be operable or configured to drive the fan 359. The blower assembly 350 may draw in air, and air discharged from the blower assembly 350, alternatively referred to as circulating air flow, and may then pass over the plurality of heat exchangers in a counter-flow relationship to the flow of combustion air. The circulating airflow may be thereafter directed to a space to be heated through a duct system (not shown).
The plurality of motors (e.g., inducer motor 332 and blower motor 352) may operate at a low speed when the furnace 300 is operating at its low firing rate (low stage operation). The plurality of motors may operate at a high speed when the furnace 300 is operating at its high firing rate (high stage operation). The plurality of motors may be designed to operate at continuously variable speeds. Alternatively, for the two stage furnace 300 the plurality of motors may be designed to selectively operate and at a plurality of operating speeds including a steady state low operating speed and a steady state high operating speed.
The furnace 300 may include a dual motor controller 400 that, in part, may selectively control the operating speed of the plurality of motors (i.e., the inducer motor 332 and the blower motor 352) by generating and transmitting control signals. For example, depending on operating conditions, the dual motor controller 400 may select a speed from the plurality of operating speeds for the plurality of motors. In addition, the dual motor controller 400 may select a time, duration, ramp rate, and torque at which the plurality of motors accelerate to and decelerate from the selected speed.
The dual motor controller 400 is configured to independently control a speed and/or torque of the blower motor 352 and a speed and/or torque of the inducer motor 332. The dual motor controller 400 is configured to communicate with a furnace control board 402. The furnace control board 402 is configured to provide torque and/or speed set points that the dual motor controller 400 executes and provide speed feedback to the furnace control board 402. The furnace control board 402 may be configured to implement a constant airflow algorithm for the blower motor 352 by communicating the torque and/or speed set points to the dual motor controller 400 and receiving information about the speed of the blower motor 352 from the dual motor controller 400. When used with an ultra-low NOx furnace it will operate in constant torque mode not constant airflow. The furnace control board 402 is also configured to receive information about the speed of the inducer motor 332 from the dual motor controller 400 and use this information to confirm normal operation of the overall inducer assembly (e.g., induced draft blower 330 and an inducer motor 332).
The dual motor control board provide speed feedback of the inducer motor to the furnace control board and uses this information to verify operation of the inducer motor.
The combustion efficiency of an induced-draft gas-fired furnace may be optimized by maintaining the proper ratio of the gas input rate and the combustion airflow rate. Generally, the ideal ratio may be offset somewhat for safety purposes by providing for slightly more combustion air (that is, excess air) than that required for optimum combustion efficiency. While
In the following sample use cases, the furnace control board 402 may determine the requirements from the low pressure switch 342 and high pressure switch 344 in response to call-for-heat signals received from the thermostat 500 located in the space to be heated. From this determination, the dual motor controller 400 may generate speed control signals to drive the inducer motor 332.
In a first sample use case, when the thermostat 500 provides a call-for-heat signal to the dual motor controller 400, the dual motor controller 400 may determine that furnace 300 is to operate at the low firing rate. The dual motor controller 400 may accelerate the inducer motor 332 to a first pre-ignition speed. The first pre-ignition speed for the inducer motor 332 may be a first pre-ignition steady state speed that may correspond to a first pre-ignition differential pressure for the heat exchanger assembly. The first pre-ignition differential pressure for the heat exchanger assembly may be sufficient to actuate the low pressure switch 342, but not the high pressure switch 344.
When the first differential pressure for the heat exchanger assembly has been sustained for a preset time, the gas valve 318 may actuate to its low open state. Under this condition, the gas valve 318 may supply gas at the low firing rate to the burner assembly 312. The gas is ignited and begins heating the combustion gases passing through the heat exchanger assembly. This heating may cause a change in the density of the combustion air which, in turn, may cause an increase in the differential pressure across the heat exchange assembly.
The speed of the inducer motor 332 may be then reduced to a first post-ignition speed. The first post-ignition speed for the inducer motor 332 is a first post-ignition steady state speed that corresponds to a first post ignition differential pressure for the heat exchanger assembly. The first post-ignition differential pressure for the heat exchanger assembly is somewhat lower than the first pre-ignition value.
After reducing the speed of inducer motor 332 to the first post-ignition speed, dual motor controller 400 may provide a signal that causes blower motor 352 to accelerate to a first post-ignition speed. The first post-ignition speed for the blower motor 352 may be a first steady state speed that corresponds to a circulating airflow at which the furnace 300 may be designed to operate during low stage operations.
In a second sample use case, when the thermostat 500 provides a call-for-heat signal to the furnace control board 402, the furnace control board 402 may determine that furnace 300 is to operate at the high firing rate and send a command to the dual motor controller 400. The dual motor controller 400 may accelerate the inducer motor 332 to a second pre-ignition speed. The second pre-ignition speed for the inducer motor 332 may be a second pre-ignition steady state speed that may correspond to a second pre-ignition differential pressure for the heat exchanger assembly. The second pre-ignition speed for the inducer motor 332 may be sufficient to actuate both low pressure switch 342 and high pressure switch 344.
When the second pre-ignition differential pressure for the heat exchanger assembly has been sustained for a preset time, the gas valve 318 may be actuated to the high open state. Under this condition, the gas valve 318 may supply gas at the high firing rate to burner assembly 312. The gas may be ignited and begin heating the combustion gases passing through the heat exchanger assembly. This heating may cause a change in the density of the combustion gases which, in turn, may cause an increase in the differential pressure across the heat exchange assembly.
The speed of inducer motor 332 may then be increased (rather than decreased as in the first sample use case) to a second post-ignition speed to attain a second post-ignition steady state speed. The second post-ignition steady state speed may correspond to a second post-ignition differential pressure for the heat exchanger assembly that is somewhat higher than the pre-ignition value. After moving the speed of inducer motor 332 to the second post-ignition speed, dual motor controller 400 may cause blower motor 352 to accelerate to a second blower motor speed. The second post-ignition speed for the blower motor 352 may be a second steady state speed that may correspond to the circulating airflow value at which furnace 300 is designed to operate.
In order to reduce the operating cost of furnace 300 by improving its annual fuel utilization efficiency (AFUE), the combustion airflow for furnace 300 may be adapted to provide for intermediate stages of operation between the low stage of operation and the high stage of operation. This may be accomplished by providing one or more additional pressure switches that actuate at heat exchanger pressure levels intermediate that of the plurality of pressure switches. Circuitry in the furnace control board 402, however, may be limited to two inputs on which the plurality of pressure switches may provide pressure signals related to the pressure in the heat exchanger assembly.
In an embodiment, the dual motor controller 400 may be a smart electronically commuted motor (ECM) that is a dual motor controller. The dual motor controller 400 is a single control that is configured to drive the blower motor 352 and the inducer motor 332. The dual motor controller 400 is in electronic communication (e.g., provides phase current) with the blower motor 352 and the inducer motor 332. The dual motor controller 400 is connected to the blower motor 352 through a blower motor wire 354. Electronic signals are transmitted from the dual motor controller 400 to the blower motor 352 through the blower motor wire 354. The dual motor controller 400 is connected to the inducer motor 332 through an inducer motor wire 334. Electronic signals are transmitted from the dual motor controller 400 to the inducer motor 332 through the inducer motor wire 334.
The dual motor controller 400 may be an electronic controller including a processor and an associated memory comprising computer-executable instructions (i.e., computer program product) that, when executed by the processor, cause the processor to perform various operations. The processor may be, but is not limited to, a single-processor or multi-processor system of any of a wide array of possible architectures, including field programmable gate array (FPGA), central processing unit (CPU), application specific integrated circuits (ASIC), digital signal processor (DSP) or graphics processing unit (GPU) hardware arranged homogenously or heterogeneously. The memory may be but is not limited to a random access memory (RAM), read only memory (ROM), or other electronic, optical, magnetic or any other computer readable medium.
The dual motor controller 400 is electrically connected to a single power source 410. The single power source 410 may be an alternating current power source. The single power source 410 may also be a 15 amp alternating current power source. The dual motor controller 400 may be electrically connected to the furnace control board 402, which is electrically connected to the single power source 410 through a power source wire 412 and junction box (not shown).
The dual motor controller 400 may include a single DC link bank that is shared between the power modules of the blower motor 352 and the inducer motor 332. The DC link bank may include a single VFD, single diode rectifier, power factor correction (PFC) circuits, a single electromagnetic interference (EMI) filter, and input protections. A single power source 410 provides all the auxiliary voltages for the single VFD, single diode rectifier, PFC circuits, the single EMI filter, and input protections.
The dual motor controller 400 may be located in a controller housing 430 within a blower assembly compartment 356 for the blower assembly 350 and the blower motor 352. The blower assembly compartment 356 houses the blower assembly 350 and the blower motor 352. The blower assembly compartment 356 is attached to the combustion compartment 360 that houses the heat exchanger 320, 324. The combustion compartment 360 houses the induced draft blower 330 and the inducer motor 332. The combustion compartment 360 may be thermally separated from blower assembly compartment 356 to prevent elevated temperatures in the blower assembly compartment 356 using a device, such as, for example, a thermal barrier, cell panel and cell panel insultation. The blower assembly compartment 356 may be attached to the combustion compartment 360.
The location of the blower assembly 350 and the blower motor 352 within the blower assembly compartment 356 may be configured to protect the blower assembly 350 and the blower motor 352 from the elevator temperatures of the combustion compartment 360. Advantageously, this eliminates (or at least mitigates) the need for any additional thermal protection for the dual motor controller 400. Further, since the inducer motor 332 conventionally had a dedicated inducer motor controller attached to the inducer motor 332, the inducer motor 332 needed additional thermal protection to protect the dedicated inducer motor controller but since the dual motor controller 400 is housed in the blower assembly compartment 356 and not the inducer motor 332, the inducer motor 332 no longer needs the additional thermal protection (although additional thermal protection may be provided, in certain instances).
The controller housing 430 housing the dual motor controller 400 may be attached to a blower housing 358 that houses a fan 359 of the blower assembly 350. The blower housing 358 encircles the fan 359 of the blower assembly 350. The blower housing 358 may be cylindrically shaped as illustrated in
Referring now to
At block 704, a blower motor 352 is installed within the blower assembly 350. At block 706, the blower assembly 350 is installed within a blower assembly compartment 356 of the furnace 300. The blower motor 352 may be operably connected to the fan 359 of the blower assembly 350.
At block 708, an inducer motor 332 is installed in the induced draft blower 330. At block 710, the induced draft blower 330 is installed in a combustion compartment 360 of the furnace 300. The inducer motor 332 may be operably connected to the induced draft blower 330.
At block 712, a dual motor controller 400 is installed within the blower assembly compartment 356. The dual motor controller 400 is configured to independently control at least one of a torque or a speed of the blower motor 352 and the inducer motor 332.
The method 700 may further include that the dual motor controller 400 is installed in a controller housing 430. The method 700 may further include that the controller housing 430 is attached to a blower housing 358 configured to house a fan 359 of the blower assembly 350.
The method 700 may further include that a power source wire 412 is attached to furnace control board 402, which is electrically connected to the dual motor controller 400. The power source wire 412 electrically connects the dual motor controller 400 to a single power source 410.
While the above description has described the flow process of
Referring now to
At block 804, the dual motor controller 400 independently controls at least one of a torque or a speed of the blower motor 352 and the inducer motor 332. The dual motor controller 400 and the blower motor 352 are located within a blower assembly compartment 356. Block 804 may consist of block 806, block 808, block 810, and/or block 812.
At block 806, the dual motor controller 400 independently controls a torque of the blower motor 352.
At block 808, the dual motor controller 400 independently controls a speed of the blower motor 352.
At block 810, the dual motor controller 400 independently controls a torque of the inducer motor 332.
At block 812, the dual motor controller 400 independently controls a speed of the inducer motor 332.
The inducer motor 332 is located in a combustion compartment 360. The combustion compartment 360 being thermally separated from the blower assembly compartment 356. The dual motor controller 400 is electrically connected to a furnace control board 402. A power source wire 412 electrically connects the furnace control board 402 to a single power source 410.
While the above description has described the flow process of
The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ±8% or 5%, or 2% of a given value.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof
As described above, embodiments can be in the form of processor-implemented processes and devices for practicing those processes, such as processor. Embodiments can also be in the form of computer program code (e.g., computer program product) containing instructions embodied in tangible media (e.g., non-transitory computer readable medium), such as floppy diskettes, CD ROMs, hard drives, or any other non-transitory computer readable medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes a device for practicing the embodiments. Embodiments can also be in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes a device for practicing the exemplary embodiments. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits.
While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.
This application claims priority to U.S. Provisional Application No. 63/293,381 filed Dec. 23, 2021, all of which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63293381 | Dec 2021 | US |
