System and method for operating a variable speed compressor of an air conditioner unit

Abstract

An air conditioner unit includes a variable speed compressor for circulating refrigerant through a refrigeration circuit and a controller configured to initiate a run cycle, initiate a compressor transition timer, and determine an unfiltered compressor speed. The unfiltered compressor speed is fixed based on a selected run mode until the compressor transition timer reaches a predetermined transition delay time, after which a closed loop feedback control algorithm is used to determine the unfiltered compressor speed. The controller is further configured to operate the variable speed compressor at a target compressor speed that is modified from the unfiltered compressor speed based on identification of a speed modification condition, such as identification of insufficient dehumidification, speed limit, or one or more resonance avoidance zones.

Description

Technical Field

[0001] This disclosure relates generally to air conditioning units, and more specifically to a method of operating a variable-speed compressor of an air conditioning unit. Background Technology

[0002] Air conditioning units, or air conditioning units, are typically used to regulate indoor temperature, for example, in buildings such as residential and office buildings. These units usually consist of a closed refrigeration loop to heat or cool indoor air. Typically, the indoor air is recirculated while being heated or cooled. A variety of sizes and configurations are available for these air conditioning units. For example, some units may have a section installed indoors that is connected, for example, to another section located outdoors via pipes or conduits that deliver refrigerant. These types of units are often used to regulate air in large spaces.

[0003] Another type of air conditioning unit, often referred to as a single-package vertical unit (SPVU) or package terminal air conditioner (PTAC), can be used to regulate the temperature in, for example, a single room or a group of rooms in a building. These units typically operate like a split heat pump system, except that the indoor and outdoor sections are defined by a partition, and all system components are housed within a single package installed in a through-wall bushing within an opening in the building's exterior wall. When a conventional PTAC operates in cooling or heating mode, the compressor circulates the refrigerant within the sealed system, while indoor and outdoor fans respectively force airflow through the indoor and outdoor heat exchangers.

[0004] It is worth noting that the compressor speed of an air conditioning unit often varies depending on the room's temperature requirements. However, certain operating conditions or system characteristics may lead to undesirable operating ranges for the compressor. For example, the compressor may periodically generate unwanted noise and vibration, which may disturb room occupants or cause premature wear and failure of the compressor or other sealed system components. This may be especially true when the compressor operates at a speed corresponding to the resonant frequency of the compressor and / or other components of the air conditioning unit.

[0005] Furthermore, the air conditioner's compressor may periodically operate beyond various unit power limits, potentially generating excessive heat that could affect the electronic components of various units, or it may operate in other areas that are preferably avoided. Additionally, under certain conditions and circumstances, the target compressor speed may not be sufficient to properly dehumidify the room. Therefore, the compressor may need to operate at a higher speed to properly cool the indoor heat exchanger, thereby aiding in the removal of moisture from the air. Conventional compressor control algorithms cannot compensate for such speed modification conditions.

[0006] Therefore, improvements to air conditioner units and operating methods that avoid undesirable compressor operating conditions will be useful. More specifically, packaged terminal air conditioner units that regulate compressor operation to avoid operating in resonance zones (areas where power should be limited) or high-temperature zones will be particularly beneficial. Summary of the Invention

[0007] Aspects and advantages of the invention will be set forth in part in the description which follows, or may be apparent from the description or may be learned by practice of the invention.

[0008] In one exemplary embodiment, an air conditioning unit is provided, the air conditioning unit comprising: a refrigeration circuit including an outdoor heat exchanger and an indoor heat exchanger; a variable-speed compressor operatively coupled to the refrigeration circuit and configured to cause a refrigerant flow through the outdoor heat exchanger and the indoor heat exchanger; and a controller operatively coupled to the variable-speed compressor. The controller is configured to initiate an operating cycle and activate a compressor switching timer, determine an unfiltered compressor speed based at least in part on the compressor switching timer, identify speed modification conditions, generate a target compressor speed based at least in part on the unfiltered compressor speed and the identification of the speed modification conditions, and operate the variable-speed compressor at the target compressor speed.

[0009] In another exemplary embodiment, a method of operating an air conditioning unit is provided. The air conditioning unit includes a refrigeration circuit and a variable-speed compressor, the variable-speed compressor being operatively coupled to the refrigeration circuit and configured to cause a refrigerant flow through the refrigeration circuit. The method includes initiating an operating cycle and activating a compressor switching timer, determining an unfiltered compressor speed based at least in part on the compressor switching timer, identifying speed modification conditions, generating a target compressor speed based at least in part on the unfiltered compressor speed and the identification of the speed modification conditions, and operating the variable-speed compressor at the target compressor speed.

[0010] These and other features, aspects, and advantages of the invention will become more readily understood with reference to the following description and the appended claims. Embodiments of the invention are illustrated in conjunction with the accompanying drawings, which are incorporated in and constitute a part of this specification, and together with the description serve to explain the principles of the invention. Attached Figure Description

[0011] Referring to the accompanying drawings, the complete and practicable disclosure of the invention, including its best mode, is set forth in the specification for those skilled in the art.

[0012] Figure 1 A perspective view of an air conditioner unit according to an exemplary embodiment of the present disclosure is provided, wherein, for illustrative purposes, a portion of the indoor section is separated from the remainder of the air conditioner unit.

[0013] Figure 2 yes Figure 1 Another perspective view of the components of the indoor section of an exemplary air conditioning unit.

[0014] Figure 3 This is a schematic diagram of a refrigeration circuit according to an embodiment of the present disclosure.

[0015] Figure 4 According to one embodiment of this disclosure Figure 1 A rear perspective view of the outdoor portion of an exemplary air conditioning unit, showing ventilation holes in the partition.

[0016] Figure 5 According to one embodiment of this disclosure Figure 4 A front perspective view of an exemplary partition, in which the ventilation door is shown in the open position.

[0017] Figure 6 According to one embodiment of this disclosure, a fan assembly for providing supplemental air is included. Figure 4 Rear perspective view of an exemplary air conditioning unit and partition.

[0018] Figure 7 yes Figure 1 A side cross-sectional view of an exemplary air conditioning unit.

[0019] Figure 8 A method for controlling a variable-speed compressor of a complete terminal air conditioning unit is shown according to an embodiment of the present disclosure.

[0020] Figure 9 A method for controlling a variable-speed compressor of a complete terminal air conditioning unit is shown according to another embodiment of the present disclosure.

[0021] The repeated use of reference numerals in this specification and drawings is intended to indicate the same or similar features or elements of the invention. Detailed Implementation

[0022] Reference will now be made in detail to embodiments of the invention, one or more of which are illustrated in the accompanying drawings. Each example is provided by way of explanation and not by way of limitation. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from the scope or spirit thereof. For example, a feature shown or described in part as one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0023] Now for reference Figure 1 and Figure 2 An air conditioning unit 10 is provided. The air conditioning unit 10 is a single-unit type air conditioner, also commonly referred to as an indoor air conditioner or a physical terminal air conditioner (PTAC). Unit 10 includes an indoor section 12 and an outdoor section 14, and is generally defined in a vertical direction V, a lateral direction L, and a transverse direction T. Each direction V, L, and T is perpendicular to each other, such that an orthogonal coordinate system is generally defined.

[0024] The housing 20 of unit 10 can accommodate various other components of unit 10. Housing 20 may include, for example, a rear grille 22 and a room front section 24, which can be spaced apart in the lateral direction T by a through-wall sleeve 26. The rear grille 22 may be part of the outdoor section 14, and the room front section 24 may be part of the indoor section 12. Components of the outdoor section 14, such as the outdoor heat exchanger 30, the outdoor fan 32, and the compressor 34, can be accommodated within the through-wall sleeve 26. As shown, a fan shroud 36 can additionally enclose the outdoor fan 32.

[0025] The indoor section 12 may include, for example, an indoor heat exchanger 40, a blower fan or indoor fan 42, and a heating unit 44. These components may be housed, for example, at the rear of the front section 24 of the room. Additionally, a partition 46 may typically support and / or house various other components or portions thereof of the indoor section 12, such as the indoor fan 42 and the heating unit 44. The partition 46 may typically separate and define the indoor section 12 and the outdoor section 14.

[0026] The outdoor heat exchanger 30 and the indoor heat exchanger 40 can be components of a sealed system or a refrigeration circuit 48, which is... Figure 3The diagram is schematically shown. The refrigeration circuit 48 may further include, for example, a compressor 34 and an expansion device 50. As shown, the compressor 34 and expansion device 50 may be in fluid communication with the outdoor heat exchanger 30 and the indoor heat exchanger 40 to allow refrigerant to flow through them, as is generally understood. More specifically, the refrigeration circuit 48 may include various lines for allowing refrigerant to flow between the various components of the refrigeration circuit 48, thereby providing fluid communication between them. Thus, refrigerant can flow through such lines from the indoor heat exchanger 40 to the compressor 34, from the compressor 34 to the outdoor heat exchanger 30, from the outdoor heat exchanger 30 to the expansion device 50, and from the expansion device 50 to the indoor heat exchanger 40. As the refrigerant flows toward and through these various components, the refrigerant may typically undergo a phase change associated with the refrigeration cycle, as is generally understood. Suitable refrigerants for use in refrigeration circuit 48 may include pentafluoroethane, difluoromethane, or mixtures such as R410a, but it should be understood that this disclosure is not limited to such examples, but any suitable refrigerant may be used.

[0027] As understood in the art, the refrigeration circuit 48 can operate alternately as a refrigeration component (and thus perform a refrigeration cycle) or a heat pump (and thus perform a heat pump cycle). Figure 3 As shown, when the refrigeration circuit 48 operates in cooling mode and thus performs a refrigeration cycle, the indoor heat exchanger 40 acts as an evaporator, and the outdoor heat exchanger 30 acts as a condenser. Alternatively, when the components operate in heating mode and thus perform a heat pump cycle, the indoor heat exchanger 40 acts as a condenser, and the outdoor heat exchanger 30 acts as an evaporator. The outdoor heat exchanger 30 and the indoor heat exchanger 40 may each include coils through which refrigerant can flow for heat exchange purposes, as generally understood.

[0028] According to an exemplary embodiment, compressor 34 may be a variable-speed compressor. In this respect, compressor 34 can operate at various speeds according to the current air conditioning needs of the room and the demands from the refrigeration circuit 48. For example, according to an exemplary embodiment, compressor 34 may be configured to operate at any speed between a minimum speed, such as 1500 rpm, and a maximum rated speed, such as 3500 rpm. It is worth noting that the use of variable-speed compressor 34 enables efficient operation of refrigeration circuit 48 (and therefore air conditioning unit 10), minimizes unnecessary noise when compressor 34 does not need to operate at full speed, and ensures a comfortable environment in the room.

[0029] Specifically, according to an exemplary embodiment, compressor 34 may be a variable frequency compressor. In this regard, compressor 34 may include a power inverter, power electronics, a rectifier, or other control electronics suitable for converting alternating current (AC) power input into direct current (DC) power for the compressor. The inverter electronics can regulate the DC power output to any suitable DC voltage corresponding to a specific operating speed of the compressor. In this way, compressor 34 can be regulated to any suitable operating speed, for example, from 0% to 100% of the compressor's full rated power and / or speed. This can help the compressor operate precisely at the desired operating power and speed to meet system requirements, while maximizing efficiency and minimizing unnecessary system cycles, energy use, and noise.

[0030] In the exemplary embodiment shown, the expansion device 50 may be disposed in the outdoor portion 14 between the indoor heat exchanger 40 and the outdoor heat exchanger 30. According to the exemplary embodiment, the expansion device 50 may be an electronic expansion valve capable of controlled expansion of the refrigerant, as known in the art. More specifically, the electronic expansion device 50 may be configured to precisely control the expansion of the refrigerant to maintain, for example, a desired temperature difference of the refrigerant across the indoor heat exchanger 40. In other words, the electronic expansion device 50 throttles the flow of refrigerant based on the amount of temperature difference or superheat across the indoor heat exchanger 40, thereby ensuring that the refrigerant enters the compressor 34 in a gaseous state. According to alternative embodiments, the expansion device 50 may be a capillary tube or another suitable expansion device configured for a thermodynamic cycle.

[0031] According to the exemplary embodiment shown, outdoor fan 32 is an axial fan, while indoor fan 42 is a centrifugal fan. However, it should be understood that, according to alternative embodiments, outdoor fan 32 and indoor fan 42 can be any suitable fan type. Furthermore, according to the exemplary embodiment, outdoor fan 32 and indoor fan 42 are variable-speed fans, for example, similar to variable-speed compressor 34. For example, outdoor fan 32 and indoor fan 42 can rotate at different speeds, thereby producing different airflow rates. It may be desirable to operate fans 32, 42 at speeds below their maximum rated speed to ensure that cooling circuit 48 operates safely and properly at speeds below its maximum rated speed, for example, to reduce noise when full-speed operation is not required. Furthermore, according to alternative embodiments, fans 32, 42 can be operated to induce supplemental air into the room.

[0032] According to the illustrated embodiment, the indoor fan 42 can operate as an evaporator fan in the cooling circuit 48 to facilitate airflow through the indoor heat exchanger 40. Therefore, the indoor fan 42 can be positioned downstream of the indoor heat exchanger 40 and downstream of the heating unit 44 along the direction of indoor airflow. Alternatively, the indoor fan 42 can be positioned upstream of the indoor heat exchanger 40 along the direction of indoor airflow and can operate to facilitate airflow through the indoor heat exchanger 40.

[0033] The heating unit 44 in the exemplary embodiment includes one or more heater groups 60. Each heater group 60 can operate as needed to generate heat. In some embodiments as shown, three heater groups 60 may be utilized. However, alternatively, any suitable number of heater groups 60 may be utilized. Each heater group 60 may further include at least one heater coil or coil channel 62, such as two heater coils or coil channels 62 in the exemplary embodiment. Alternatively, other suitable heating elements may be utilized.

[0034] The operation of the air conditioning unit 10, including compressor 34 (and therefore typically refrigeration circuit 48), indoor fan 42, outdoor fan 32, heating unit 44, expansion device 50, and other components of refrigeration circuit 48, can be controlled by a processing device such as controller 64. Controller 64 can communicate with such components of air conditioning unit 10 (e.g., via a suitable wired or wireless connection). Controller 64 may include memory and one or more processing devices, such as microprocessors, CPUs, etc., such as general-purpose or special-purpose microprocessors, operable to execute programming instructions or microcontroller code related to the operation of unit 10. Memory may represent random access memory such as DRAM, or read-only memory such as ROM or flash memory. In one embodiment, the processor executes programming instructions stored in the memory. Memory may be a component separate from the processor, or it may be included on a board within the processor.

[0035] Unit 10 may additionally include a control panel 66 and one or more user inputs 68, which may be included in the control panel 66. The user inputs 68 may communicate with the controller 64. A user of unit 10 may interact with the user inputs 68 to operate unit 10, and user commands may be transmitted between the user inputs 68 and the controller 64 to facilitate the operation of unit 10 based on such user commands. A display 70 may be additionally located in the control panel 66 and may communicate with the controller 64. The display 70 may be, for example, a touchscreen or other text-readable display, or alternatively, may simply be a light that can be activated and deactivated as needed to provide indications of, for example, events or settings of unit 10.

[0036] Brief reference Figure 4Ventilation opening 80 may be defined in partition 46 for providing fluid communication between indoor section 12 and outdoor section 14. Ventilation opening 80 may be used in an already installed air conditioning unit 10 to allow outdoor air to flow into the room through indoor section 12. In this regard, in some cases, it may be desirable to allow outside air (i.e., "makeup air") to flow into the room to, for example, meet government regulations, compensate for negative pressure generated in the room, etc. In this way, according to an exemplary embodiment, makeup air can be supplied to the room through ventilation opening 80 when needed.

[0037] like Figure 5 As shown, the ventilation door 82 can be pivotally mounted to the partition 46, near the ventilation opening 80, to open and close the ventilation opening 80. More specifically, as shown, the ventilation door 82 is pivotally mounted to the interior-facing surface of the interior portion 12. The ventilation door 82 can be configured to pivot between a first closed position and a second open position. In the first closed position, the ventilation door 82 prevents airflow between the exterior portion 14 and the interior portion 12; in the second open position, the ventilation door 82 is in the open position (e.g., Figure 5 (As shown) and allows supplemental air to flow into the room. According to the illustrated embodiment, the ventilation door 82 can be pivoted between open and closed positions by a motor 84 controlled by a controller 64 or by any other suitable method.

[0038] In some cases, it may be desirable to treat or regulate the supplemental air flowing through the vent 80 before it is blown into the room. For example, outdoor air with a relatively high humidity level may need to be treated before entering the room. Furthermore, if the outdoor air is cold, it may be desirable to heat the air before it is blown into the room. Therefore, according to an exemplary embodiment of this subject matter, unit 10 may further include an auxiliary sealing system located above the vent 80 for regulating the supplemental air. The auxiliary sealing system may be a small sealing system that functions similarly to the cooling circuit 48, but only regulates the air flowing through the vent 80. According to alternative embodiments (such as those described herein), the supplemental air may be forced through the vent 80 without the aid of an auxiliary sealing system. Instead, the supplemental air forced through the vent 80 may be regulated at least partially by the cooling circuit 48, for example, by passing through the indoor heat exchanger 40. Furthermore, the supplemental air may be regulated immediately upon entering through the vent 80, or after being combined with an airflow introduced through the indoor heat exchanger 40.

[0039] Now for reference Figure 6Fan assembly 100 will be described according to an exemplary embodiment of this subject matter. According to the illustrated embodiment, fan assembly 100 is generally configured to facilitate a supplemental airflow through vent 80 and into a conditioned room without the aid of an auxiliary sealing system. However, it should be understood that fan assembly 100 may be used in conjunction with a supplemental air module that includes an auxiliary sealing system for regulating the supplemental airflow. As shown, fan assembly 100 includes an auxiliary fan 102 for facilitating a supplemental airflow through fan duct 104 and through vent 80 into the indoor portion 12.

[0040] According to the illustrated embodiment, the auxiliary fan 102 is an axial fan located at the inlet of the fan duct 104 (e.g., upstream of the vent 80). However, it should be understood that, according to alternative embodiments, any other suitable number, type, and configuration of fans or blowers can be used to induce the flow of supplemental air. Furthermore, the auxiliary fan 102 can be located at any other suitable location within the air conditioning unit 10, and the auxiliary fan 102 can be located within or in fluid communication with the fan duct 104. The embodiments described herein are merely exemplary and are not intended to limit the scope of the subject matter.

[0041] Now for reference Figure 7 The operation of unit 10 will be described below according to exemplary embodiments. More specifically, the operation of components within the indoor section 12 during cooling operation or cooling cycle of unit 10 will be described. For simplicity of discussion, the operation of the auxiliary fan 102 that provides supplemental air through vent 80, for example, as if the vent 82 were closed, will be omitted. Although a cooling cycle will be described, it should be further understood that, according to alternative embodiments, indoor heat exchanger 40 and / or heating unit 44 are used to heat indoor air. Furthermore, although the operation of unit 10 is described below with reference to an exemplary packaged terminal air conditioning unit, it should be further understood that aspects of this subject matter can be used for any other suitable air conditioning unit, such as a heat pump or split unit system.

[0042] As shown, the front 24 of unit 10 typically defines an air inlet 110 and an exhaust vent 112 for circulating airflow throughout the room (indicated by arrow 114). In this regard, an indoor fan 42 is typically configured to draw in air 114 through the air inlet 110 and to direct airflow through the indoor heat exchanger 40 before expelling air 114 from the exhaust vent 112. According to the illustrated embodiment, the air inlet 110 is located near the bottom of unit 10, and the exhaust vent 112 is located near the top of unit 10. However, it should be understood that, according to alternative embodiments, the air inlet 110 and exhaust vent 112 may have any other suitable size, shape, location, or configuration.

[0043] During the cooling cycle, the refrigeration circuit 48 is typically configured to allow cold refrigerant to pass through the indoor heat exchanger 40 in order to reduce the temperature of the airflow 114 before it is discharged back into the room. Specifically, during cooling operation, the controller 64 may be provided with a target temperature, such as a target temperature set by a user for a desired room temperature. Typically, components of the refrigeration circuit 48, the outdoor fan 32, the indoor fan 42, and other components of unit 10 operate to continuously cool the airflow.

[0044] To facilitate the operation of the cooling circuit 48 and other components of unit 10, unit 10 may include various sensors for detecting conditions inside and outside unit 10. These conditions can be fed to controller 64, which can make decisions regarding the operation of unit 10 to correct undesirable conditions or otherwise regulate the airflow 114 entering the room. For example, as Figure 7 As best shown, unit 10 may include an indoor temperature sensor 120 positioned and configured to measure the indoor temperature within a room. Additionally, unit 10 may include an indoor humidity sensor 122 positioned and configured to measure the indoor humidity within a room. In this way, unit 10 can be used to regulate the airflow 114 entering the room until the measured indoor temperature reaches a desired target temperature and / or humidity level.

[0045] As used herein, "temperature sensor" or equivalent is intended to refer to any suitable type of temperature measurement system or device positioned at any suitable location for measuring a desired temperature. Thus, for example, temperature sensor 120 can each be any suitable type of temperature sensor, such as a thermistor, thermocouple, resistance temperature detector, semiconductor-based integrated circuit temperature sensor, etc. Furthermore, temperature sensor 120 can be positioned at any suitable location and can output a signal, such as a voltage, to the controller that is proportional to and / or indicates the temperature being measured. Although exemplary positioning of the temperature sensor is described herein, it should be understood that, according to alternative embodiments, unit 10 may include any other suitable number, type, and location of temperature sensors, humidity sensors, and / or other sensors.

[0046] As used herein, the term "humidity sensor" or equivalent may be intended to refer to any suitable type of humidity measurement system or apparatus positioned at any suitable location for measuring desired humidity. Thus, for example, humidity sensor 122 may refer to any suitable type of humidity sensor, such as a capacitive digital sensor, a resistive sensor, and a thermal conductivity humidity sensor. Furthermore, humidity sensor 122 may be positioned at any suitable location and may output a signal, such as a voltage, to the controller that is proportional to and / or indicates the measured humidity. Although exemplary positioning of the humidity sensor is described herein, it should be understood that, according to alternative embodiments, unit 10 may include any other suitable number, type, and location of humidity sensors.

[0047] Having now presented the construction of the air conditioner unit 10 and the configuration of the controller 64 according to exemplary embodiments, exemplary methods 200, 300 for operating the complete terminal air conditioner unit will be described. Although the following discussion relates to exemplary methods 200, 300 for operating the air conditioner unit 10, those skilled in the art will understand that exemplary methods 200, 300 are applicable to the operation of various other air conditioning devices. In exemplary embodiments, the various method steps as disclosed herein may be performed by the controller 64 or a separate dedicated controller.

[0048] Now for reference Figure 8 Method 200 includes, in step 210, initiating an operating cycle for the air conditioning unit. In this regard, for example, the air conditioning unit 10 can be triggered to begin performing an air conditioning process, for example, by selectively operating the compressor 34, outdoor fan 32, indoor fan 42, etc., to facilitate heat pump operation and heating or cooling of indoor air 114. The initiation of the operating cycle can be triggered by any suitable source in any suitable manner and can correspond to any suitable sealing system requirements, as described below according to exemplary embodiments.

[0049] In this regard, for example, the thermostat can initiate an operating cycle based at least in part on the difference between the measured temperature (e.g., as measured by the indoor temperature sensor 120) and the temperature setpoint of the air-conditioned room. In this regard, if the measured temperature differs from the temperature setpoint by more than a predetermined amount, unit 10 can initiate an operating cycle to bring the measured temperature closer to the temperature setpoint. According to an exemplary embodiment, the operating cycle can also be initiated directly by the user of unit 10, for example, via the control panel 66.

[0050] According to an exemplary embodiment, the sealing system requirements can vary depending on the heating or cooling capacity requirements of a specific room. Generally, sealing system requirements typically vary proportionally with the speed of the corresponding sealing system components and the desired rate of temperature change. In this regard, higher sealing system requirements may correspond to increased compressor speed, increased fan speed, etc., to improve the ability of unit 10 to quickly regulate the room. In contrast, for example, when the measured temperature is close to the target temperature and lower power consumption and noise generation are desired, lower sealing system requirements may correspond to reduced compressor speed, fan speed, etc.

[0051] It should be understood that, according to the exemplary embodiments, heating / cooling capacity or sealing system requirements may vary based on the magnitude of the temperature difference between the measured temperature and the target temperature or temperature setpoint. Therefore, for example, if the temperature difference exceeds a lower difference threshold (e.g., ±2 degrees Fahrenheit), an operating cycle (e.g., a low-level operating cycle where compressor 34, external fan 32, and indoor fan 42 operate at lower speeds) can be initiated with low sealing system requirements. In contrast, if the temperature difference exceeds a higher difference threshold (e.g., ±4 degrees Fahrenheit), the sealing system requirements may be higher (e.g., a high-level operating cycle where compressor 34, outdoor fan 32, and indoor fan 42 operate at higher speeds).

[0052] According to some other embodiments, the heating or cooling capacity or sealing system requirement of the operating cycle can be directly manipulated by the user of unit 10. In this regard, for example, the user can directly manipulate control panel 66 to increase or decrease the intensity of the operating cycle or sealing system requirement. Thus, if the user wishes to cool the room quickly, the user can select user input 68 corresponding to the maximum cooling capacity or the highest level of sealing system requirement. It should be understood that the operating cycle can be performed in an open manner or can rely on temperature and humidity feedback (e.g., receiving indoor temperature sensor 120 and / or indoor humidity sensor 122).

[0053] It is worth noting that at the start of the operating cycle, when compressor 34 first begins circulating the refrigerant flow within refrigeration circuit 48, unit 10 may have little or no effect on the temperature inside the air-conditioned room. Specifically, the cooling capacity of the sealed system may take several minutes to take effect. Therefore, immediately starting closed-loop operation of the sealed system may be undesirable, as this could result in undesirable high operating speeds. Therefore, step 210 may include starting the compressor switching timer, for example, simultaneously with starting compressor 34. As will be described in more detail below, the compressor speed of variable-speed compressor 34 may be determined at least in part based on the compressor switching timer.

[0054] Specifically, step 220 typically involves determining the unfiltered compressor speed of the variable-speed compressor, at least in part, based on a compressor switching timer. As used herein, "unfiltered compressor speed" can generally refer to a target compressor speed primarily based on the sealing system capacity (e.g., how quickly the room should be heated / cooled). In this respect, for example, at the start of the operating cycle, the variable-speed compressor 34 can operate at a fixed compressor speed. As mentioned above, the fixed compressor speed can vary based on sealing system requirements, for example, based on the heating or cooling capacity required by unit 10. In this respect, sealing system requirements can be at a low level, a high level, an intermediate level, or any other suitable operating level, and the fixed compressor speed can vary accordingly.

[0055] For example, at the start of a running cycle, when the temperature difference between the measured temperature and the setpoint temperature is relatively small, the sealing system requirements may be low. Therefore, a fixed compressor speed can be between approximately 800 and 2800 rpm, between approximately 1000 and 2600 rpm, between approximately 1200 and 2400 rpm, between approximately 1500 and 2100 rpm, or approximately 1800 rpm.

[0056] In contrast, if the temperature difference between the measured temperature and the setpoint temperature is relatively large at the start of the operating cycle, the sealing system requirements may be high. Therefore, a fixed compressor speed can be between approximately 2600 and 4600 rpm, between approximately 2800 and 4400 rpm, between approximately 3000 and 4200 rpm, between approximately 3300 and 3900 rpm, or approximately 3600 rpm. It should be understood that these fixed operating speeds are merely exemplary and can vary while remaining within the scope of this subject matter. Furthermore, it should be understood that although only two operating modes or levels are described, unit 10 can operate at any other suitable intermediate operating level while remaining within the scope of this subject matter.

[0057] It is worth noting that after the sealing system begins to properly heat / cool the room, it may be desirable to switch to a more active closed-loop control system. In this regard, the closed-loop control system may rely on temperature and / or humidity feedback from one or more system sensors, such as indoor temperature sensor 120 and indoor humidity sensor 122. Therefore, method 200 may further include determining that a compressor switching timer (e.g., activated at the start of the operating cycle in step 210) has exceeded a predetermined switching delay time. Typically, the predetermined switching delay time may correspond to the amount of time it takes for the sealing system to begin effectively heating or cooling the room. This predetermined switching delay time may be set by the user or manufacturer, may be determined empirically, or may be set in any other suitable manner. For example, according to an exemplary embodiment, the predetermined switching delay time may be between about 30 seconds and 10 minutes, between about 1 minute and 5 minutes, between about 2 minutes and 4 minutes, or about 3 minutes. Other switching delay times are possible and are within the scope of this subject matter.

[0058] It is worth noting that step 220, which determines the unfiltered compressor speed of the variable-speed compressor based at least in part on the current compressor switching timer, may include determining the unfiltered compressor speed based on a closed-loop feedback control algorithm when it is determined that the compressor switching timer has exceeded a predetermined switching delay time. For example, according to an exemplary embodiment, the closed-loop feedback control algorithm may include a proportional control algorithm, a proportional-integral control algorithm (e.g., a PI controller), or a proportional-integral-derivative control algorithm (e.g., a PID controller).

[0059] Typically, a closed-loop feedback control algorithm can operate the compressor 34 to minimize the difference between the measured indoor temperature and the setpoint temperature. In this regard, implementation of the closed-loop feedback control algorithm may include obtaining the indoor temperature (e.g., using an indoor temperature sensor 120), determining the error value between the indoor temperature and the setpoint temperature, and passing or inputting the error value into the closed-loop feedback control algorithm to generate an unfiltered compressor speed as a control input that minimizes the error. Details regarding the operation of the closed-loop feedback control algorithm are generally well known in the art, and for the sake of brevity, further detailed discussion will be omitted here.

[0060] It is worth noting that step 220 typically produces an unfiltered compressor speed, which may correspond to the desired speed of the variable-speed compressor 34 for effectively heating, cooling, and / or dehumidifying the room where unit 10 is located. However, during operation of unit 10, certain conditions or operating characteristics may exist that may necessitate modification of the unfiltered compressor speed. Therefore, step 230 may typically include identifying speed modification conditions, such as insufficient dehumidification, speed limitations, or identification of one or more resonance avoidance zones, each of which will be described in more detail below.

[0061] Furthermore, step 240 may include generating a target compressor speed based at least in part on the identification of the unfiltered compressor speed and speed modification conditions. According to an exemplary embodiment, step 250 may include operating the variable-speed compressor at the target compressor speed. It is noteworthy that the target compressor speed may be modified from the unfiltered compressor speed, and such modification may depend on the speed modification conditions detected in step 230. Various speed modification conditions and their corresponding effects on the unfiltered compressor speed will now be described according to exemplary embodiments of this subject matter. However, it should be understood that other speed modification conditions are possible and within the scope of this subject matter.

[0062] According to an exemplary embodiment, identifying speed modification conditions may typically include identifying insufficient dehumidification. In this regard, insufficient dehumidification may generally refer to a situation where the room is not properly dehumidified by unit 10, or when the dehumidification process is inefficient or unnecessary. For example, method 200 may include measuring the humidity of the conditioned room (e.g., using indoor humidity sensor 122) and determining that the measured humidity exceeds a predetermined humidity threshold. According to an alternative embodiment, unit 10 may use indoor humidity sensor 122 to identify the dehumidification rate and may compare the dehumidification rate with a target dehumidification rate to determine whether unit 10 has properly dehumidified the room.

[0063] As described above, for example, under certain conditions where compressor 34 needs to operate at a higher speed to properly cool the indoor heat exchanger in order to remove moisture from the air, dehumidification insufficiency may occur. Therefore, if the unfiltered compressor speed (e.g., determined in step 220) is too low to facilitate the dehumidification process, the identification of dehumidification insufficiency can lead to the implementation of a lower speed boundary, or lower speed limit, for compressor 34. Thus, the target compressor speed can be increased relative to the unfiltered compressor speed, for example, set as a lower speed boundary as a result of the identification of dehumidification insufficiency. More specifically, for example, if the unfiltered compressor speed requires compressor 34 to operate at 2000 RPM, but dehumidification insufficiency is identified as requiring the compressor speed to operate at a minimum of 2400 RPM, the target compressor speed can be set to 2400 RPM instead of 2000 RPM. In this way, the lower speed boundary caused by dehumidification insufficiency can serve as a lower limit for the unfiltered compressor speed.

[0064] According to another exemplary embodiment, identifying speed modification conditions may include identifying a speed limit or power limit state of compressor 34. In this regard, certain operating conditions may arise where maintaining a high speed for compressor 34 is not desired. For example, a speed limit may be implemented if the power consumption limit of compressor 34 has been exceeded, the control board temperature has risen to an undesirable high level, or another unit operating characteristic indicates that the compressor speed should be reduced or limited to a specific speed. Therefore, when a speed limit is identified, the unfiltered compressor speed (e.g., determined in step 220) is limited to the upper speed boundary corresponding to the speed limit. Specifically, for example, if the unfiltered compressor speed is 5000 RPM and the inverter board temperature begins to rise above a predetermined temperature threshold, the unfiltered compressor speed may be reduced to a predetermined value, such as 4000 to 4500 RPM, to prevent the inverter control board from overheating.

[0065] According to some other embodiments, identifying speed modification conditions may include identifying one or more resonance avoidance zones. If the unfiltered compressor speed falls within one or more resonance avoidance zones, the unfiltered compressor speed can be adjusted to fall outside these zones. For example, resonance avoidance zones may typically correspond to operating speeds or frequencies that generate excessive vibrations within the compressor 34, sealing system, or more generally unit 10. If left unchecked, these vibrations can lead to degradation of system components and premature failure of unit 10. (See also...) Figure 9 A more detailed description is provided of an exemplary method for adjusting the speed of an unfiltered compressor to avoid one or more resonance avoidance zones. It should be understood that method 200 ( Figure 8 ) and 300 Figure 9 The steps in the process can be interchanged, combined, and varied to create additional methods for operating the air conditioning unit.

[0066] Now for reference Figure 9 Method 300 includes, in step 310, initiating an operating cycle for the air conditioning unit. Step 320 may include determining the unfiltered compressor speed of the variable-speed compressor based at least in part on sealing system requirements. For example, as explained above with reference to steps 210 and 220, unit 10 may receive a command to initiate an operating cycle and may initiate sealing system operation in response to sealing system requirements, which may be low for smaller temperature differences and high for larger temperature differences, or may include any other suitable sealing system requirements and corresponding operating speeds and parameters of unit 10.

[0067] Step 330 may include determining that the unfiltered compressor speed falls within a resonance avoidance zone defined by the minimum and maximum resonant frequencies. In this regard, the resonance avoidance zone may be the operating frequency band of the compressor 34, which may generate undesirable vibrations within unit 10. For example, the resonance avoidance zone may be defined as a compressor operating speed between 2600 and 2800 RPM, or any other operating speed range. Therefore, it is generally desirable to avoid operating the compressor 34 within this operating zone. It is worth noting that, when no other constraints are present, it may be desirable to default the compressor operating speed to the higher side of the resonance avoidance zone, such as at the maximum resonant frequency. However, according to the exemplary embodiment, other system operating parameters or characteristics may make operation at the maximum resonant frequency undesirable.

[0068] For example, if a speed limit or power limit has been identified or triggered during the operation of unit 10, and if the maximum resonant frequency exceeds the identified speed or power limit, it might be desirable to set the compressor speed based on the minimum resonant frequency. Therefore, step 340 may include identifying a target compressor speed that avoids the resonance avoidance zone. Specifically, step 340 may include setting the target compressor speed to the minimum resonant frequency if the unfiltered compressor speed exceeds the maximum speed limit. Furthermore, step 340 may include setting the target compressor speed to the maximum resonant frequency if the unfiltered compressor speed is below the maximum speed limit.

[0069] Specifically, for example, if the unfiltered compressor speed is 3000 RPM, the resonance avoidance zone is identified as being between 2900 and 3100 RPM, and there is no power limit (or a power limit above the maximum resonant frequency of 3100 RPM, such as 4000 RPM), the target compressor speed can be set to 3100 RPM. In contrast, if the unfiltered compressor speed is 4000 RPM, the resonance avoidance zone is identified as being between 3900 and 4200 RPM, and the power limit has been set to 4100 RPM, the target compressor speed can be set to 3900 RPM to avoid the resonance avoidance zone and the power limit range. Step 350 typically includes operating the variable-speed compressor at the target compressor speed. It is worth noting that implementing method 300 can generally help the compressor 34 and unit 10 operate in a way that effectively cools or heats the room without generating excessive noise or harmful vibration, and without exceeding the power limit to protect system components.

[0070] Although method 300 is described herein as facilitating the operation of compressor 34 to avoid a single resonance avoidance zone, it should be understood that unit 10 may have more than one dwell avoidance zone. Therefore, method 300 may include operating compressor 34 to avoid each dwell avoidance zone. Furthermore, it should be understood that these resonance avoidance zones can be programmed by the user or maintenance technician of the air conditioning unit. In this respect, these zones can be determined empirically and can be programmed into the controller to improve the future performance of unit 10.

[0071] For the purposes of explanation and discussion, Figure 8 and Figure 9 The steps performed in a specific order are described. Using the disclosure provided herein, those skilled in the art will understand that the steps of any method discussed herein can be adapted, rearranged, extended, omitted, or modified in various ways without departing from the scope of this disclosure. Furthermore, although aspects of methods 200 and 300 are explained using unit 10 as an example, it should be understood that the method can be applied to operating any suitable air conditioning unit.

[0072] This written description uses examples to disclose the invention (including the best mode) and also enables any person skilled in the art to practice the invention, including making and using any device or system and performing any incorporated methods. The scope of patentability of the invention is defined by the claims and may include other examples that would occur to a person skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. An air conditioning unit, comprising: A refrigeration circuit, the refrigeration circuit including an outdoor heat exchanger and an indoor heat exchanger; A variable-speed compressor, operatively coupled to the refrigeration circuit and configured to cause refrigerant to flow through the outdoor heat exchanger and the indoor heat exchanger; and A controller, operably coupled to the variable-speed compressor, is configured to: Start the operating cycle, start the variable speed compressor to run at a fixed compressor speed at the beginning of the operating cycle, and start the compressor switching timer at the same time as starting the variable speed compressor; It is determined that the compressor switching timer has exceeded the predetermined switching delay time; In response to determining that the compressor switching timer has exceeded the predetermined switching delay time, the unfiltered compressor speed is determined at least in part based on a closed-loop feedback control algorithm; Conditions for modifying recognition speed; The target compressor speed is generated based at least in part on the identification of the unfiltered compressor speed and the speed modification conditions; as well as The variable speed compressor operates at the target compressor speed; The air conditioning unit further includes an indoor temperature sensor, wherein determining the target compressor speed is based at least in part on the closed-loop feedback control algorithm, including: The indoor temperature is obtained using the aforementioned indoor temperature sensor; Determine the error value between the indoor temperature and the setpoint temperature; and The error value is passed to the closed-loop feedback control algorithm to determine the unfiltered compressor speed.

2. The air conditioning unit according to claim 1, wherein when the sealing system of the operating cycle requires a low heating or cooling mode, the fixed compressor speed is between 1200 and 2400 rpm.

3. The air conditioning unit according to claim 1, wherein when the sealing system of the operating cycle requires a low heating or cooling mode, the fixed compressor speed is 1800 rpm.

4. The air conditioning unit according to claim 1, wherein when the sealing system of the operating cycle requires a high heating or cooling mode, the fixed compressor speed is between 3000 and 4200 rpm.

5. The air conditioning unit according to claim 1, wherein when the sealing system of the operating cycle requires a high heating or cooling mode, the fixed compressor speed is 3600 rpm.

6. The air conditioning unit according to claim 1, wherein the predetermined switching delay time is between two minutes and four minutes.

7. The air conditioner unit according to claim 1, wherein the closed-loop feedback control algorithm includes a proportional control algorithm, a proportional-integral control algorithm, or a proportional-integral-derivative control algorithm.

8. The air conditioning unit of claim 1, wherein identifying the speed modification condition includes identifying insufficient dehumidification, and wherein generating the target compressor speed based at least in part on the identification of the unfiltered compressor speed and the speed modification condition includes: Based on the identification of insufficient dehumidification, the speed of the unfiltered compressor is limited to the lower speed boundary.

9. The air conditioning unit of claim 8, wherein identifying the insufficient dehumidification includes: Humidity is measured using a humidity sensor; as well as The humidity is determined to exceed a predetermined humidity threshold.

10. The air conditioning unit of claim 1, wherein identifying the speed modification condition includes identifying a speed limit, and wherein generating the target compressor speed based at least in part on the identification of the unfiltered compressor speed and the speed modification condition includes: Based on the identification of the speed limit, the speed of the unfiltered compressor is limited to the upper speed boundary.

11. The air conditioning unit of claim 10, wherein identifying the speed limit includes determining that a power consumption limit has been exceeded or determining that the control board temperature has exceeded a temperature threshold.

12. The air conditioning unit of claim 1, wherein identifying the speed modification condition includes identifying one or more resonance avoidance zones, and wherein generating the target compressor speed based at least in part on the identification of the unfiltered compressor speed and the speed modification condition includes: Adjust the speed of the unfiltered compressor to avoid the one or more resonance avoidance zones.

13. A method of operating an air conditioning unit, the air conditioning unit including a refrigeration circuit and a variable-speed compressor, the variable-speed compressor being operatively coupled to the refrigeration circuit and configured to cause a refrigerant flow through the refrigeration circuit, the method comprising: Start the operating cycle, start the variable speed compressor to run at a fixed compressor speed at the beginning of the operating cycle, and start the compressor switching timer at the same time as starting the variable speed compressor; It is determined that the compressor switching timer has exceeded the predetermined switching delay time; In response to determining that the compressor switching timer has exceeded the predetermined switching delay time, the unfiltered compressor speed is determined at least in part based on a closed-loop feedback control algorithm; Conditions for modifying recognition speed; The target compressor speed is generated based at least in part on the identification of the unfiltered compressor speed and the speed modification conditions; as well as The variable speed compressor operates at the target compressor speed; The determination of the target compressor speed, based at least in part on the closed-loop feedback control algorithm, includes: Obtain indoor temperature; Determine the error value between the indoor temperature and the setpoint temperature; and The error value is passed to the closed-loop feedback control algorithm to determine the unfiltered compressor speed.

14. The method of claim 13, wherein when the sealing system of the operating cycle requires a low heating or cooling mode, the fixed compressor speed is between 1200 and 2400 rpm, and wherein when the sealing system of the operating cycle requires a high heating or cooling mode, the fixed compressor speed is between 3000 and 4200 rpm.

15. The method of claim 13, wherein identifying the speed modification condition includes identifying insufficient dehumidification, and wherein generating the target compressor speed based at least in part on the identification of the unfiltered compressor speed and the speed modification condition includes: Based on the identification of insufficient dehumidification, the speed of the unfiltered compressor is limited to the lower speed boundary.

16. The method of claim 13, wherein identifying the speed modification condition includes identifying a speed limit, and wherein generating the target compressor speed based at least in part on the identification of the unfiltered compressor speed and the speed modification condition includes: Based on the identification of the speed limit, the speed of the unfiltered compressor is limited to the upper speed boundary.

17. The method of claim 13, wherein identifying the speed modification condition includes identifying one or more resonance avoidance regions, and wherein generating the target compressor speed based at least in part on the identification of the unfiltered compressor speed and the speed modification condition includes: Adjust the speed of the unfiltered compressor to avoid the one or more resonance avoidance zones.

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