Backup power system for HVAC&r system

Abstract

A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor configured to direct a working fluid along a working fluid circuit, a variable speed drive (VSD) configured to supply power to a motor of the compressor, and a backup power system including a battery configured to supply power directly to a DC link of the VSD in response to an interruption in supply of power from a primary power source to the VSD.

Description

BACKUP POWER SYSTEM FOR HVAC&R SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 755,911, entitled “BACKUP POWER SYSTEM FOR HVAC&R SYSTEM,” filed February 7, 2025, which is hereby incorporated by reference in its entirety for all purposes.BACKGROUND

[0002] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0003] Heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems, such as chiller systems (e.g., vapor compression systems), utilize a working fluid (e.g., refrigerant) that changes phases between vapor, liquid, and combinations thereof in response to exposure to different temperatures and pressures within components of the chiller system. HVAC&R systems may include a compressor for circulating a working fluid (e.g., refrigerant) along a working fluid circuit and through heat exchangers of the HVAC&R system. For example, the HVAC&R system may include a heat exchanger configured to receive the working fluid and a conditioning fluid, and the heat exchanger may place the working fluid in the heat exchange relationship with the conditioning fluid. The conditioning fluid may be directed from the heat exchanger to other equipment, such as air handlers, to condition other fluids, such as air, in a building.

[0004] Unfortunately, supply of power to HVAC&R systems may be temporarily interrupted in some instances. For example, a utility grid or other power source mayexperience an outage and may be unable to supply power to the HVAC&R system. Some HVAC&R systems may be implemented with a generator configured to supply power to the HVAC&R systems during a power outage from a utility grid or standard power source. However, there may be a time delay between interruption in supply of power from the utility grid and initiated operation of the generator, which may result in a temporary shutdown of the HVAC&R system. The HVAC&R system may therefore be unable operate to condition the conditioning fluid or otherwise provide cooling to a load during the time delay. Additionally or alternatively, some HVAC&R systems may include an uninterruptible power supply configured to supply power to various components of the HVAC&R system during a power outage. Unfortunately, incorporation of an uninterruptible power supply may be associated with various drawbacks. For example, uninterruptible power supplies may induce or otherwise cause inefficiencies associated with the HVAC&R system, such as power losses, power inefficiencies, increased power consumption, increased maintenance demands, and so forth.SUMMARY

[0005] In one embodiment, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor configured to direct a working fluid along a working fluid circuit, where the compressor includes a motor. The HVAC&R system also includes a variable speed drive (VSD) configured to supply power to the motor of the compressor, and a backup power system configured to supply power directly to the VSD in response to an interruption in supply of power from a primary power source to the VSD.

[0006] In another embodiment, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor having a motor and a variable speed drive (VSD) configured to supply power to the motor, where the VSD includes a rectifier, a direct current (DC) link, and an inverter. The HVAC&R system also includes a backup power system configured to supply power to the VSD in response to aninterruption in supply of power from a primary power source to the VSD, where the backup power system includes a battery.

[0007] In a further embodiment, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor configured to circulate a working fluid through a working fluid circuit, a motor configured to drive the compressor, and a variable speed drive (VSD) configured to supply power to the motor, where the VSD includes a rectifier, a direct current (DC) link, and an inverter. The HVAC&R system also includes a backup power system configured to supply power to the VSD in response to an interruption in supply of power from a primary power source to the VSD, where the backup power system includes a battery, and the battery is directly electrically connected to the DC link of the VSD.DRAWINGS

[0008] Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which:

[0009] FIG. 1 is a perspective view of a building that utilizes an embodiment of a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system in a commercial setting, in accordance with an aspect of the present disclosure;

[0010] FIG. 2 is a perspective view of an embodiment of a vapor compression system, in accordance with an aspect of the present disclosure;

[0011] FIG. 3 is a schematic of an embodiment of a vapor compression system, in accordance with an aspect of the present disclosure; and

[0012] FIG. 4 is a schematic of an embodiment of a portion of an HVAC&R system, illustrating a variable speed drive (VSD) and a backup power system implemented with the VSD, in accordance with an aspect of the present disclosure.DETAILED DESCRIPTION

[0013] One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers’ specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0014] When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0015] As used herein, the terms “approximately,” “generally,” “substantially,” and so forth, are intended to convey that the property value being described may be within a relatively small range of the property value, as those of ordinary skill would understand. For example, when a property value is described as being “approximately” equal to (or, for example, “substantially similar” to) a given value, this is intended to convey that the property value may be within + / - 5%, within + / - 4%, within + / - 3%, within + / - 2%, within + / - 1%, or even closer, of the given value. Similarly, when a given feature is described as being “substantially parallel” to another feature, “generally perpendicular” to another feature, and so forth, this is intended to convey that the given feature is within + / - 5%, within + / - 4%, within + / - 3%, within + / - 2%, within + / - 1%, or even closer, to having the described nature, such as being parallel to another feature, being perpendicularto another feature, and so forth. Mathematical terms, such as “parallel” and “perpendicular,” should not be rigidly interpreted in a strict mathematical sense, but should instead be interpreted as one of ordinary skill in the art would interpret such terms. For example, one of ordinary skill in the art would understand that two lines that are substantially parallel to each other are parallel to a substantial degree, but may have minor deviation from exactly parallel.

[0016] A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system may be implemented to thermally regulate a space within a building, home, or other suitable structure. For example, the HVAC&R system may include a vapor compression system (e.g., vapor compression circuit) that transfers thermal energy between a working fluid (e.g., a heat transfer fluid, such as a refrigerant) and a fluid to be conditioned, such as water, air, or another suitable fluid. The vapor compression system may include one or more heat exchangers, such as a condenser and an evaporator, that are fluidly coupled to one another via a working fluid circuit (e.g., one or more conduits). The vapor compression system may also include a compressor configured to circulate the working fluid through the working fluid circuit and thereby enable the transfer of thermal energy between the condenser and the evaporator and respective fluids directed through the condenser and the evaporator.

[0017] In many cases, the compressor of the HVAC&R system may be driven by a motor. The motor may be communicatively coupled to a control system, which may include a variable speed drive (VSD). The control system may operate and control the motor to cause the motor to drive the compressor at a desired speed (e.g., a variable speed, a selected speed of a plurality of speeds). In some cases, the control system may further adjust the speed of the motor and the compressor during operation of the HVAC&R system. For example, a power output of the motor may be selected (e.g., by the control system) based on a capacity (e.g., a cooling demand) of the HVAC&R system. The control system may operate the VSD to adjust a speed and / or power output of the motor and / or compressor.

[0018] Unfortunately, a supply of power to the HVAC&R system may be temporarilyinterrupted in some instances. For example, the HVAC&R system may typically receive power from a utility grid or other power source (e.g., primary power source), but the utility grid may experience a temporary power outage that interrupts supply of power from the utility grid to the HVAC&R system. In such instances, the HVAC&R system may receive a temporary supply of power from an alternative source. Unfortunately, many systems and devices configured to provide temporary backup power to the HVAC&R system are susceptible to various drawbacks. For example, generators configured to supply temporary power to HVAC&R systems typically do not provide power to the HVAC&R system immediately upon interruption of the supply of power from a utility grid or other primary power source. Thus, the HVAC&R system may temporarily shut down and be unable to operate to condition (e.g., cool) a conditioning fluid. Such interruptions may adversely impact systems and / or environments that are conditioned via the conditioning fluid.

[0019] Some HVAC&R systems may include an uninterruptible power supply (UPS) configured to provide temporary power to various components (e.g., control system components) of the HVAC&R system, such as control boards, controllers, control panels, sensors, interfaces, and so forth. Unfortunately, UPSs typically cause inefficiencies in HVAC&R systems. For example, UPSs are typically associated with power losses, power inefficiencies, increased power consumption, increased maintenance demands, and so forth. UPSs also generate heat that demand cooling. Therefore, improved backup power systems for HVAC&R systems are desired.

[0020] Accordingly, embodiments of the present disclosure are directed to backup power system for an HVAC&R system that is configured to supply backup power more readily and more efficiently during an interruption in supply of power from a primary power source (e.g., utility grid). For example, present embodiments enable more rapid (e g., uninterrupted) supply of backup power to the HVAC&R system (e.g., one or more components of the HVAC&R system) between an interruption in supply of power from a primary power source (e.g., utility grid) and operation of an alternative primary power source (e.g., generator) configured to supply power to the HVAC&R system. Indeed, the presently disclosed techniques enable uninterrupted supply of power to the HVAC&Rsystem with improved efficiency (e.g., reduced power losses, reduced power consumption) and in a manner that enables uninterrupted operation of the HVAC&R system. The HVAC&R system may therefore continue to condition (e.g., cool) a conditioning fluid for supply to equipment to be conditioned (e.g., server equipment) even during an interruption in supply of power from the primary power source. As described in further detail below, the backup power system may include one or more batteries, which may be configured to supply power to a variable speed drive (VSD) of the HVAC&R system that is configured to drive operation of a motor and / or a compressor of the HVAC&R system.

[0021] Turning now to the drawings, FIG. 1 is a perspective view of an embodiment of an application for a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system 10. In the illustrated embodiment, the HVAC&R system 10 is implemented with a building 12. However, it should be appreciated that the HVAC&R system 10 may be utilized to provide conditioning (e.g., heating, cooling) in a variety of different settings. For example, the HVAC&R system 10 may provide cooling to data centers, electrical devices, freezers, coolers, or other environments through vaporcompression refrigeration, absorption refrigeration, or thermoelectric cooling. Additionally, the HVAC&R system 10 may be used in residential, commercial, light industrial, industrial, and in any other application for heating or cooling a load, a volume, or enclosure, such as a residence, building, structure, and so forth. Moreover, the HVAC&R system 10 may be used in industrial applications for cooling and / or heating of various fluids. In certain embodiments, the HVAC&R system 10 may be used to thermally regulate components within a building, such as electric and / or computer devices that generate heat (e.g., in a data center).

[0022] The HVAC&R system 10 may include a vapor compression system 14 (e.g., chiller, air-cooled chiller, water-cooled chiller, vapor compression circuit) that generates and supplies a chilled liquid, which may be used to cool the building 12. The HVAC&R system 10 may also include a boiler 16 to supply warm liquid to heat the building 12 and an air distribution system which circulates air through the building 12. As shown, the vapor compression system 14 (e.g., chiller) is disposed on the roof of the building 12, andthe boiler 16 is located in the basement; however, the vapor compression system 14 and the boiler 16 may be located in other equipment rooms or areas next to the building 12. in the vapor compression system 14 may be an air-cooled chiller that implements a refrigeration cycle to cool water or other conditioning fluid and is configured to reject heat to an ambient (e.g., outdoor) environment surrounding the vapor compression system 14 and / or the building 12. The vapor compression system 14 is housed within a structure that includes a working fluid circuit (e.g., vapor compression circuit), a conditioning fluid circuit, and associated equipment such as pumps, valves, and piping. For example, the vapor compression system 14 may be a single package rooftop unit that incorporates the working fluid circuit. The boiler 16 is a closed vessel in which water or other conditioning fluid is heated.

[0023] The air distribution system may include one or more air handlers 18 and ductwork 20 configured to direct air into and / or from conditioned spaces within the building 12. The air handlers 18 are coupled to the ductwork 20, which is adapted to distribute air between the air handlers 18 and may receive air from an outside intake. The air handlers 18 include heat exchangers that circulate cold conditioning fluid (e.g., water) received from the vapor compression system 14 and hot conditioning fluid (e.g., water) received from the boiler 16 to provide heated or cooled air to conditioned spaces within the building 12. The heat exchangers may be fluidly connected to the boiler 16 and the vapor compression system 14 via conduits 22 configured to circulate the conditioning fluid between the air handlers 18, the vapor compression system 14, and the boiler 16.

[0024] Fans within the air handlers 18 draw air through the heat exchangers and direct the conditioned air to environments within the building 12, such as rooms, apartments, or offices, to maintain the environments at a designated temperature. A control device 24 of each air handler 18, shown in the illustrated embodiment as including a thermostat, may be used to designate the temperature of the conditioned air. The control device 24 also may be used to control the flow of air through and from the air handlers 18. Other devices may be included in the system, such as control valves that regulate the flow of conditioning fluid and pressure and / or temperature transducers or switches that sense the temperatures and pressures of the conditioning fluid, the air, andso forth. Moreover, the control devices 24 may include computer systems that are integrated with or separate from other building control or monitoring systems, and even systems that are remote from the building 12. The HVAC&R system 10 is shown with separate air handlers 18 on each floor of the building 12, but in other embodiments, the HVAC&R system 10 may include air handlers 18 and / or other components that may be shared between or among floors.

[0025] In some embodiments, the vapor compression system 14 (e.g., chiller) may be configured to supply a chilled fluid (e.g., cold water) to (e g., directly to) equipment to be conditioned (e.g., cooled) within the building 12. For example, the building 12 may be a data center having electronic equipment 26 (e.g., server equipment, computer equipment, etc.) disposed therein. The electronic equipment 26 may be liquid-cooled. In the illustrated embodiment, the electronic equipment may be configured to receive chilled liquid from the vapor compression system 14 (e.g., via one or more of the conduits 22) and may place components of the electronic equipment 26 in a heat exchange relationship with the chilled liquid to enable cooling of the electronic equipment 26.

[0026] FIG. 2 is a schematic of an embodiment of a vapor compression system 30 (e.g., mechanical cooling system, air-cooled vapor compression system, chiller system, vapor compression system 14) having a flash tank 32 (e.g., an economizer tank). For example, the vapor compression system 30 may be a part of an air-cooled chiller. However, it should be appreciated that the disclosed techniques may be incorporated with a variety of other types of chillers, such as water-cooled chillers. The vapor compression system 30 includes a working fluid circuit 34 (e.g., vapor compression circuit) configured to circulate a working fluid, such as a refrigerant, therethrough with a compressor 36 (e.g., screw compressor, centrifugal compressor) disposed along the working fluid circuit 34. The working fluid circuit 34 also includes the flash tank 32, a condenser 38 (e.g., heat exchanger, air-cooled condenser), expansion valves or devices 40, and an evaporator 42 (e.g., liquid chiller, heat exchanger). The components of the working fluid circuit 34 enable heat transfer between the working fluid and other fluids (e.g., a conditioning fluid, air, water) in order to provide cooling to an environment, such as an interior of the building 12. In some embodiments, the working fluid circuit 34 may supply the workingfluid directly to a component (e.g., cold plate, computer equipment) to be cooled via transfer of heat to the working fluid.

[0027] Some examples of working fluids that may be used as refrigerants in the vapor compression system 30 are hydrofluorocarbon (HFC) based working fluids, for example, R-410A, R-407, R-134a, R-1234ze, R1233zd, hydrofluoro-olefin (HFO), “natural” refrigerants like ammonia (NH3), R-717, carbon dioxide (CO2), R-744, or hydrocarbon based working fluids, water vapor, working fluids with low global warming potential (GWP), or any other suitable working fluid. Other possible working fluids that may be circulated through the vapor compression system 30 include R-123, R-514A, R-1224yd, R-1233zd, R-134a, R-1234ze, R-1234yf, R-1311, and R-32. In some embodiments, the vapor compression system 30 may be configured to efficiently utilize working fluids having a normal boiling point of about 19 degrees Celsius (66 degrees Fahrenheit or less) at one atmosphere of pressure, also referred to as low pressure working fluids, versus a medium pressure working fluids, such as R-134a. As used herein, “normal boiling point” may refer to a boiling point temperature measured at one atmosphere of pressure.

[0028] The vapor compression system 30 may further include a control panel 44 (e.g., a controller) that has an analog to digital (A / D) converter 46, a microprocessor 48, a non-volatile memory 50, and / or an interface board 52. In some embodiments, the vapor compression system 30 may use one or more of a variable speed drive (VSDs) 54 and a motor 56. The motor 56 may drive the compressor 36 and may be powered by the VSD 54. The VSD 54 receives alternating current (AC) power having a particular fixed line voltage and fixed line frequency (e.g., fixed frequency alternating current) from an AC power source and provides power having a variable voltage and frequency (e.g., variable frequency alternating current) to the motor 56. In other embodiments, the motor 56 may be powered directly from an AC or direct current (DC) power source. The motor 56 may include any type of electric motor that can be powered by the VSD 54 or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor.

[0029] The compressor 36 compresses a working fluid vapor and may deliver the vapor to an oil separator 58 that separates oil from the working fluid vapor. The working fluid vapor is then directed toward the condenser 38, and the oil is returned to the compressor 36. The working fluid vapor delivered to the condenser 38 may transfer heat to a cooling fluid at the condenser 38. For example, the cooling fluid may be ambient air 60 forced across heat exchanger coils of the condenser 38 by condenser fans 62. The working fluid vapor may condense to a working fluid liquid in the condenser 38 as a result of thermal heat transfer with the cooling fluid (e.g., the ambient air 60).

[0030] The liquid working fluid exits the condenser 38 and then flows through a first expansion device 64 (e.g., the expansion device 40, an electronic expansion valve). The first expansion device 64 may be a flash tank feed valve configured to control flow of the liquid working fluid to the flash tank 32. The first expansion device 64 is also configured to lower the pressure of (e.g., expand) the liquid working fluid received from the condenser 38. During the expansion process, a portion of the liquid may vaporize, and thus, the flash tank 32 may be used to separate the vapor from the liquid received from the first expansion device 64. Additionally, the flash tank 32 may provide for further expansion of the liquid working fluid due to a pressure drop experienced by the liquid working fluid when entering the flash tank 32 (e.g., due to a rapid increase in volume experienced when entering the flash tank 32).

[0031] The vapor in the flash tank 32 may exit and flow to the compressor 36. For example, the vapor may be drawn to an intermediate stage or discharge stage of the compressor 36 (e.g., not the suction stage). A valve 66 (e.g., an economizer valve, solenoid valve) may be included in the working fluid circuit 34 to control flow of the working fluid vapor from the flash tank 32 to the compressor 36. In some embodiments, when the valve 66 is open (e.g., fully open), additional liquid working fluid within the flash tank 32 may vaporize and provide additional subcooling of the liquid working fluid within the flash tank 32. The liquid working fluid that collects in the flash tank 32 may be at a lower enthalpy than the liquid working fluid exiting the condenser 38 due to the expansion in the first expansion device 64 and / or the flash tank 32. The liquid working fluid may flow from the flash tank 32, through a second expansion device 68 (e g., theexpansion device 40, an orifice), and to the evaporator 42. In some embodiments, the working fluid circuit 34 may also include a valve 70 (e.g., a drain valve) configured to regulate flow of liquid working fluid from the flash tank 32 to the evaporator 42. For example, the valve 70 may be controlled (e.g., via the control panel 44) based on an amount of suction superheat of the working fluid.

[0032] The liquid working fluid delivered to the evaporator 42 may absorb heat from a conditioning fluid, which may be different from the cooling fluid (e.g., ambient air 60) directed across the condenser 38. The liquid working fluid in the evaporator 42 may undergo a phase change to become working fluid vapor. For example, the evaporator 42 may include a tube bundle fluidly coupled to a supply line 72 and a return line 74 that are connected to a cooling load. The conditioning fluid (e.g., water, oil, calcium chloride brine, sodium chloride brine) may be directed to enter the evaporator 42 via the return line 74 and to exit the evaporator 42 the via supply line 72. The evaporator 42 may reduce the temperature of the conditioning fluid in the tube bundle via thermal heat transfer with the working fluid so that the conditioning fluid may be utilized to provide cooling for a conditioned environment. The tube bundle in the evaporator 42 may include a plurality of tubes and / or a plurality of tube bundles. In any case, the working fluid vapor exits the evaporator 42 and returns to the compressor 36 by a suction line to complete the working fluid cycle.

[0033] FIG. 3 is a schematic of an embodiment of the vapor compression system 30 that may be used in the HVAC&R system 10. The illustrated embodiment includes certain elements and element numbers similar to those described above with reference to FIG. 2. In the illustrated embodiment of FIG. 3, the condenser 38 is water-cooled and includes a tube bundle 80 connected to a cooling tower 82, which supplies the cooling fluid to the condenser 38. Thus, the vapor compression system 30 may be a water-cooled chiller. The evaporator 42 may include a tube bundle 84 having a supply line 86S and a return line 86R connected to a cooling load 88. The conditioning fluid of the evaporator 42 (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) enters the evaporator 42 via return line 86R and exits the evaporator 42 via supply line 86S. The evaporator 42 may reduce the temperature of theconditioning fluid in the tube bundle 84 via thermal heat transfer with the working fluid. The tube bundle 84 in the evaporator 42 may include a plurality of tubes and / or a plurality of tube bundles. In any case, the vapor working fluid exits the evaporator 42 and returns to the compressor 36 by a suction line to complete the cycle.

[0034] It should be appreciated that any of the features described herein may be incorporated with the vapor compression system 14, the vapor compression system 30, and / or any other suitable HVAC&R systems. For example, the present techniques may be incorporated with any HVAC&R system a compressor, such as the compressor 36, configured to be operated via a VSD, such as the VSD 54. The discussion below describes the present techniques incorporated with embodiments of the HVAC&R system having one compressor 36 and one VSD 54. However, it should be noted that the systems and methods described herein may be incorporated with other embodiments of the HVAC&R system 10.

[0035] The present disclosure is directed to a backup power system (e.g., backup power supply system, battery backup system, integrated battery backup system) for an HVAC&R system, such as a chiller system. In particular, the backup power system is configured to supply power to a variable speed drive (VSD) of the HVAC&R system, such as the VSD 54 discussed above, during an interruption in supply of power from a primary power source. In particular, the backup power system includes one or more batteries coupled (e.g., directly coupled) to the VSD to enable uninterrupted supply of power (e.g., backup power, temporary power) to the VSD, which enables uninterrupted operation of a compressor of the HVAC&R system, during an interruption in supply of power from the primary power source. As a result, present embodiments enable uninterrupted (e.g., continuous) operation of the vapor compression system 14 to condition (e.g., cool) a load, such as a conditioning fluid that is supplied to other equipment, to enable continuous cooling of an air flow, the conditioning fluid, another fluid, equipment, such as the electronic equipment 26, or any other suitable load during an interruption of power received from the primary power source. Further, present embodiments enable uninterrupted (e.g., continuous) supply of power to the VSD with improved efficiency (e.g., reduced power losses, reduced power consumption, reducedcooling demand) relative to other systems, such as uninterruptible power supplies disposed between a primary power source and an HVAC&R system (e.g., in front of the HVAC&R system) and configured to supply power to various control system components of the HVAC&R system.

[0036] With the foregoing in mind, FIG. 4 is a schematic diagram of a portion of an embodiment of the HVAC&R system 10 (e.g., vapor compression system 30), illustrating an embodiment of the VSD 54 (e.g., VSD system) and a backup power system 100 (e.g., backup power supply system) of the vapor compression system 30. It should be understood that the VSD 54 may be configured to control (e.g., operate, power) the motor 56 of the vapor compression systems 30 (e.g., compressor 36) of FIGS. 2 and 3, for example. A power source 102 (e.g., alternating current [AC] power source, primary power source) may supply AC power to the VSD 54, and the VSD 54 may also supply AC power to the motor 56. The power source 102 may provide three-phase, fixed voltage, and fixed frequency AC power to the VSD 54 from a utility source 104 (e.g., power grid, utility grid, utility power source, primary power source) or distribution system. For example, the power source 102 may provide a first phase of AC power, a second phase of AC power, and a third phase of AC power via a first receiving line 106, a second receiving line 108, and a third receiving line 110, respectively. As will be appreciated, the HVAC&R system 10 (e.g., VSD 54) may be configured to receive power from the power source 102 (e.g., utility source 104) during normal operation of the HVAC&R system.

[0037] In some applications, the AC power may be supplied directly from an electric utility or grid (e.g., utility source 104) or from one or more transforming substations between the electric utility and the power source 102. In some embodiments, the power source 102 may supply a three phase AC voltage, or line voltage, of up to 15 kilovolts (kV) at a line frequency of between 50 Hertz (Hz) and 60 Hz to the VSD 54, depending on the corresponding power source 102. However, in other embodiments, the power source 102 can provide any suitable fixed line voltage or fixed line frequency (e.g., fixed frequency alternating current) to the VSD 54 depending on the configuration of the power source 102. In addition, a particular site (e.g., installed location of the HVAC&Rsystem 10) can have multiple power sources (e.g., AC power sources) that can satisfy different line voltage and line frequency demands. In some embodiments, the power source 102 may include a generator 112 (e.g., alternative primary power source) configured to operate during to generate and supply power to the VSD 54 (e.g., vapor compression system 30, HVAC&R system 10) during an interruption in supply of power from the utility source 104. However, it will be appreciated that the generator 112 may not be configured to generate and supply power to the VSD 54 immediately (e.g., instantaneously) upon interruption in supply of power from the utility source 104. Therefore, operation of the VSD 54 and / or the vapor compression system 30 generally may be at least temporarily suspended (e.g., shut down) and / or interrupted. Thus, the vapor compression system 30 may not operate to condition (e.g., cool) a load, such as by cooling and supplying a conditioning fluid to other equipment, during the temporary operational interruption, which may be undesirable. Accordingly, present embodiments include the backup power system 100, which is described in further detail below.

[0038] The VSD 54 directs AC power to the motor 56 at a desired voltage and a desired frequency. In certain embodiments, the VSD 54 may provide AC power to the motor 56 having higher voltages and frequencies or lower voltages and frequencies than the fixed voltage and fixed frequency AC power received from the power source 102. For example, the VSD 54 may include a rectifier 114 (e.g., converter), a direct current (DC) link 116 (e.g., DC bus), and an inverter 118. The rectifier 114 may receive alternating current having a fixed line frequency and / or a fixed line voltage (e.g., AC power, fixed frequency alternating current) from the power source 102 and convert the alternating current into direct current (DC) (e.g., DC power). The DC link 116 may filter (e g., smooth, buffer) the direct current (e.g., DC power) from the rectifier 114 and / or store electrical energy via one or more components of the DC link 116, such as one or more capacitors 120 and / or inductors. The inverter 118 may receive the direct current from the DC link 116 and convert the direct current (e.g., DC power) into variable frequency alternating current and / or variable voltage alternating current (e.g., AC power, three phase AC power) for supply to the motor 56. For example, the inverter 118 may supply the motor 56 with a first phase of AC power, a second phase of AC power, and athird phase of AC power through a first output line 122, a second output line 124, and a third output line 126, respectively.

[0039] In some embodiments, the rectifier 114 may be a pulse width modulated (PWM) boost converter or rectifier having insulated gate bipolar transistors (IGBTs) to provide a boosted DC voltage to the DC link 116 and produce a fundamental root mean square (RMS) output voltage from the VSD 54 that is greater than a fixed nominal fundamental RMS input voltage to the VSD 54. Similarly, the inverter 118 may be a PWM-type inverter with IGBTs and / or other suitable transistors (e.g., switches). Additionally or alternatively, the rectifier 114 may include a diode bridge, such as diode modules and / or silicon controlled rectifier (SCR) modules arranged in a bridge configuration. Furthermore, in some embodiments, the VSD 54 may incorporate components in addition to those shown in FIG. 4 to provide the motor 56 with appropriate output voltages and frequencies, such as circuit breakers, power busses, additional capacitors, filters, resistors, fuses, control boards, relays, and so forth.

[0040] In certain embodiments, the motor 56 may be an induction motor that is configured to be driven at variable speeds. The induction motor can have any suitable pole arrangement including two poles, four poles, six poles, or any suitable number of poles. The induction motor is configured to drive a load, such as the compressor 36 of the vapor compression system 30. In other embodiments, the motor 56 may be any suitable motor to drive the compressor 36 and / or another suitable device.

[0041] In accordance with the present techniques, the backup power system 100 is configured to enable uninterrupted supply of power to the VSD 54 to enable continued (e.g., continuous) operation of the VSD 54, and therefore the motor 56 and the compressor 36, during an interruption in supply of power from the power source 102 (e g., primary power source, utility source 104). For example, the backup power system 100 may be configured to supply backup power to (e.g., directly to) the VSD 54 upon (e.g., immediately upon) interruption of power supplied from the utility source 104 and prior to operation of the generator 112 to generate and supply alternative primary power to the VSD 54 and other components of the HVAC&R system 10. In this way, atemporary shutdown of the vapor compression system 14 (e.g., non-operation of the compressor 36) may be avoided, and the vapor compression system 14 may continuously operate to providing cooling to a load, such as by cooling and supplying a conditioning fluid (e.g., chilled fluid) to other equipment (e.g., electronic equipment 26).

[0042] As shown in the illustrated embodiment, the backup power system 100 may include a battery 150 (e.g., one or more batteries 150, a plurality of batteries 150, energy storage device) configured to store electrical energy that may be supplied to (e.g., directly to) the VSD 54 during an interruption in supply of power from the power source 102. The VSD 54 may utilize the electrical energy received from the battery 150 to operate the motor 56. In some embodiments, the VSD 54 may also utilize the electrical energy received from the battery 150 to operate one or more other components of the vapor compression system 14, such as one or more magnetic bearings of the motor 56 and / or compressor 36. To this end, the VSD 54 may be electrically coupled to the one or more magnetic bearings. The battery 150 may be electrically coupled to (e.g., directly electrically coupled to) the DC link 116 of the VSD 54 described above. To this end, the DC link 116 may include a battery input 152 (e.g., electrical connector, power input connection) configured to receive electrical energy (e.g., backup power) from the battery 150 of the backup power system 100. The battery 150 may include any suitable type of battery, such as a lithium-ion battery, a solid-state battery, an electrochemical cell battery, a primary cell battery, a secondary cell battery, a rechargeable battery, another suitable type of battery, or any combination thereof. The battery 150 may therefore be integrated with (e.g., directly electrically coupled to) the VSD 54 (e.g., DC link).

[0043] The backup power system 100 also includes a control system 154 (e.g., controller) configured to regulate operation of the backup power system 100. The control system 154 may include processing circuitry 156, and the processing circuitry 156 may include one or more microprocessors, one or more “general-purpose” microprocessors, one or more special-purpose microprocessors, one or more application specific integrated circuits (ASICS), one or more reduced instruction set (RISC) processors, one or more field programmable gate arrays (FPGAs), one or more digital signal controllers (DSCs), one or more digital signal processors (DSPs), or any combination thereof. The controlsystem 154 also includes a memory 158 (e.g., memory device, tangible non-transitory computer readable medium) that may store information, such as instructions, control software, look up tables, configuration data, other data, and so forth. The memory 158 may include a volatile memory, such as random access memory (RAM), and / or a nonvolatile memory, such as read-only memory (ROM). Additionally or alternatively, the memory 158 may include flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. In some embodiments, the memory 158 is a tangible, non-transitory, machine-readable-medium that may store machine-readable instructions for the processing circuitry 156 to execute. The memory 158 may store a variety of information and may be used for various purposes. For example, the memory 158 may store processor-executable instructions including firmware or software for the processing circuitry 156 to execute, such as instructions for controlling components of the backup power system 100. In some embodiments, the memory 158 may store operating parameter values (e.g., threshold values, predetermined values) that the processing circuitry 156 may compare to detected values of corresponding operating parameters of the VSD 54 (e.g., data received by the processing circuitry 156), such as voltage, current, temperature, and so forth. It should be appreciated that the control system 154 may be configured to enable and / or perform any of the operations of the backup power system 100 described herein.

[0044] As shown, the control system 154 may be electrically coupled to the power source 102 and the VSD 54. The control system 154 may also be configured to operate based on data and / or feedback received from one or more sensors 160. The control system 154 may also be configured to detect a loss of power supplied via the power source 102. For example, the control system 154 may receive (e.g., via one or more of the sensors 160) data and / or feedback indicative of an amount of power directed from the power source 102 (e.g., utility source 104) to the VSD 54, data indicative of a voltage (e.g., voltage differential, voltage level) across the DC link 116, or both, and the control system 154 may detect the interruption in supply of power from the power source 102 to the VSD. In response to a determination that supply of power from the power source 102 (e.g., primary power source) to the HVAC&R system 10 (e.g., VSD 54) is interrupted,the control system 154 may operate the backup power system 100 to supply backup power (e.g., direct current, electrical energy, stored in the battery 150) to the VSD 54 (e.g., from the battery 150 directly to the DC link 116). For example, in response to a determination (e.g., based on data received from one or more of the sensors 160) that the amount of power directed from the power source 102 (e.g., primary power source) to the VSD 54 and / or a voltage of or across the DC link 116 falls below a corresponding threshold value (e.g., stored on the memory 158), the control system 154 may operate the backup power system 100 to direct electrical energy (e.g., direct current, DC power) stored on the battery 150 to the DC link 116 (e.g., via the battery input 152). In some embodiments, in response to a determination that an amount of power (e.g., detected via one or more of the sensors 160) directed from the power source 102 (e.g., generator 112, utility source 104) to the VSD 54 (e.g., HVAC&R system 10) and / or a voltage of or across the DC link 116 rises above a corresponding threshold value, the control system 154 may suspend supply of electrical energy from the battery 150 to the DC link 116 and / or may enabled transition of supply of power from the power source 102 (e.g., generator 112, utility source 104) to the VSD 54.

[0045] The control system 154 may also include a timer 162 configured to monitor (e.g., track, determine) an amount of elapsed time (e.g., total elapsed time, continuous time) during which the battery 150 is utilized to supply electrical energy to the DC link 116 (e g., during an interruption in supply of power from the power source 102 to the VSD 54). In response to a determination that the amount of time determined (e.g., monitored, tracked) by the timer 162 exceeds a threshold amount of time (e.g., stored on the memory 158), the control system 154 may suspend supply of electrical energy from the battery 150 to the DC link 116 and / or may output a signal (e.g., control signal, indication, to control panel 44) to initiate shutdown of the vapor compression system 30 (e.g., compressor 36, motor 56). The threshold amount of time may be determined (e.g., predetermined) based on any suitable parameter, such as a type of the one or more batteries 150, a size of the one or more batteries 150, a charge level of the one or more batteries 150, a characteristic of the VSD 54, a characteristic of the compressor 36, a characteristic of the vapor compression system 30, another suitable parameter, or anycombination thereof. Additionally or alternatively, the control system 154 may suspend supply of electrical energy from the one or more batteries 150 to the DC link 116 and output a signal (e.g., control signal, indication, to control panel 44) to initiate shutdown of the vapor compression system 30 in response to a determination that a voltage level of the battery 150 (e.g., charge level, determined by one of the sensors 160) falls below a threshold level (e.g., stored on the memory 158).

[0046] In some embodiments, the backup power system 100 may also include a battery charging system 164 (e g., battery charger, external battery charger) configured to enable charging (e.g., electrical charging) of the battery 150 with electrical energy. For example, the battery charging system 164 may be configured to charge the battery 150 (e.g., plurality of batteries 150) with power supplied via the utility source 104 (e.g., power grid), the generator 112, or both. The battery charging system 164 may not utilize electrical energy received from the VSD 54 to charge the battery 150, in some embodiments. The VSD 54 may also not charge the battery 154 via supply of power from (e.g., directly from) the DC link 116 to the battery 150. The battery charging system 164 (e.g., battery charger) may also be electrically coupled to the power source 102 (e.g., primary power source, utility source 104, generator 112) and the battery 150 (e.g., backup power system 100) independently of the VSD 54. Thus, the battery charging system 164 (e.g., battery charger) is configured to charge the battery 150 (e.g., one or more batteries 150) independently of the VSD 54. The battery charging system 164 may be configured to charge the battery 150 via power received from the power source 102 (e.g., utility source 104) during normal operation of the HVAC&R system 10.

[0047] One or more components of the backup power system 100 may be disposed external to an enclosure 166 (e.g., electrical enclosure, electrical cabinet, VSD enclosure, control system enclosure) of the VSD 54 and / or vapor compression system 30. For example, the battery 150 and the battery charging system 164 may be disposed external to the enclosure 166. However, in some embodiments, one or more of the components of the backup power system 100 may be disposed within the enclosure 166.

[0048] Embodiments of the vapor compression system 30 incorporating the backuppower system 100 may not include an uninterruptible power supply (UPS) configured to supply power to the VSD 54. For example, the vapor compression system 30 may not include a UPS disposed between the power source 102 and the VSD 54. Thus, the vapor compression system 30 may not be susceptible to power losses, inefficiencies, and / or increased operating costs traditionally associated with a UPS disposed between the power source 102 and the VSD 54 (e.g., HVAC&R system 10, vapor compression system 30). However, in some embodiments, the vapor compression system 30 may include a UPS 168 configured to supply backup power to particular components of the vapor compression system 30, such as the control panel 44, which may not be susceptible to the power losses and / or inefficiencies associated with a UPS disposed between the power source 102 and the VSD 54.

[0049] As discussed above, embodiments of the present disclosure may provide one or more technical effects useful for enabling continuous operation of an HVAC&R system during interruption in supply of power from a primary power source. Specifically, present embodiments include a backup power system for a VSD that includes a battery configured supply backup power to the VSD in a manner that enables uninterrupted operation of the VSD and therefore a compressor of the vapor compression system. Thus, during an interruption in supply of power via the primary power source, operation of the vapor compression system may nevertheless continue, which enables continuous cooling of a conditioning fluid supplied to equipment, such as server equipment, that demands continuous cooling. The technical effects and technical problems in the specification are examples and are not limiting. It should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.

[0050] While only certain features and embodiments have been illustrated and described, many modifications and changes may occur to those skilled in the art, such as variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, such as temperatures and pressures, mounting arrangements, use of materials, colors, orientations, and so forth, without materially departing from the novel teachings and advantages of the subject matter recited in theclaims. The order or sequence of any process or method steps may be varied or resequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.

[0051] Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described, such as those unrelated to the presently contemplated best mode, or those unrelated to enablement. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.

[0052] The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function], ..” or “step for [perform]ing [a function]...”, it is intended that such elements are to be interpreted under 35 U.S.C.112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Claims

CLAIMS:

1. A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, comprising:a compressor configured to direct a working fluid along a working fluid circuit, wherein the compressor comprises a motor;a variable speed drive (VSD) configured to supply power to the motor of the compressor; anda backup power system configured to supply power directly to the VSD in response to an interruption in supply of power from a primary power source to the VSD.

2. The HVAC&R system of claim 1, wherein the backup power system comprises a battery.

3. The HVAC&R system of claim 2, wherein the VSD comprises:a rectifier configured to receive fixed frequency alternating current from the primary power source and convert the fixed frequency alternating current to direct current;a direct current (DC) link configured to receive the direct current from the rectifier and filter the direct current; andan inverter configured to receive the direct current from the DC link and convert the direct current into variable frequency alternating current.

4. The HVAC&R system of claim 3, wherein the battery of the backup power system is directly electrically coupled to the DC link of the VSD.

5. The HVAC&R system of claim 2, comprising a battery charger configured to receive power from the primary power source and charge the battery via the power.

6. The HVAC&R system of claim 5, wherein the battery charger is electrically coupled to the primary power source and the battery independently of the VSD.

7. The HVAC&R system of claim 2, wherein the backup power system comprises a control system configured to:detect the interruption in supply of power from the primary power source to the VSD; andin response to detection of the interruption in supply of power from the primary power source to the VSD, operate the backup power system 100 to direct power from the battery directly to a DC link of the VSD.

8. The HVAC&R system of claim 7, wherein the control system is configured to detect the interruption in supply of power from the primary power source to the VSD via based on data indicative of an amount of power directed from the primary power source to the VSD, data indicative of a voltage across the DC link of the VSD, or both.

9. The HVAC&R system of claim 7, wherein the control system comprises a timer configured to monitor an amount of elapsed time during which the battery is utilized to supply power to the DC link during the interruption in supply of power from the primary power source to the VSD.

10. The HVAC&R system of claim 9, wherein the control system is configured to initiate shutdown of the HVAC&R system in response to a determination that the amount of elapsed time exceeds a threshold amount of time.

11. A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, comprising:a compressor comprising a motor;a variable speed drive (VSD) configured to supply power to the motor, wherein the VSD comprises a rectifier, a direct current (DC) link, and an inverter; anda backup power system configured to supply power to the VSD in response to an interruption in supply of power from a primary power source to the VSD, wherein the backup power system comprises a battery.

12. The HVAC&R system of claim 11, wherein the battery is directly electrically coupled to the DC link.

13. The HVAC&R system of claim 11, wherein the VSD is configured to receive power from a utility grid, a generator, or both as the primary power source.

14. The HVAC&R system of claim 11, comprising a battery charger configured to charge the battery via power received from the primary power source.

15. The HVAC&R system of claim 14, wherein the battery charger is configured to charge the battery independently of the VSD.

16. The HVAC&R system of claim 11, wherein the VSD is configured to supply power received from the backup power system to a magnetic bearing of the compressor during the interruption in supply of power from the primary power source to the VSD.

17. The HVAC&R system of claim 11, comprising an enclosure, wherein the VSD is disposed within the enclosure, the backup power system is external to the enclosure, and the battery is directly electrically coupled to the DC link.

18. A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, comprising:a compressor configured to circulate a working fluid through a working fluid circuit;a motor configured to drive the compressor;a variable speed drive (VSD) configured to supply power to the motor, wherein the VSD comprises a rectifier, a direct current (DC) link, and an inverter; anda backup power system configured to supply power to the VSD in response to an interruption in supply of power from a primary power source to the VSD, wherein the backup power system comprises a battery, and the battery is directly electrically connected to the DC link of the VSD.

19. The HVAC&R system of claim 18, wherein the VSD is configured to receive power via the primary power source during normal operation of the HVAC&R system, and the HVAC&R system comprises a battery charger configured to charge the battery via power received from the primary power source during normal operation of the HVAC&R system.

20. The HVAC&R system of claim 19, wherein the battery charger is configured to electrically couple to the primary power source and the battery independently of the VSD, and the VSD is not configured to charge the battery.

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