Online optimization of compression efficiency of variable frequency drives

Abstract

A method for adjusting the compression efficiency of an HVACR system with a variable frequency drive (VFD) is disclosed. The method includes: determining a first compression efficiency; determining an operating point; determining a region of an operating graph when the difference between the operating point and a previously determined operating point exceeds a predetermined threshold; adjusting a VFD input to a first input based on the region of the operating graph; and controlling the VFD using the first input for a predetermined time period. The method further includes: determining a second compression efficiency and an operating constraint; adjusting the VFD input to a second input based on the difference between the first and second compression efficiencies and the operating constraint; and controlling the VFD using the second input. The method also includes utilizing machine learning control techniques to control multiple system variables to optimize the compression efficiency.

Description

Technical Field

[0001] This disclosure generally relates to optimizing the compression efficiency of heating, ventilation, air conditioning, and refrigeration (HVACR) systems. More specifically, this disclosure relates to systems and methods for online optimization of the compression efficiency of HVACR systems with variable frequency drives (VFDs). Background Technology

[0002] HVACR systems may include heating, ventilation, and air conditioning (HVAC) systems and / or transport climate control systems (TCCS) with transport refrigeration systems (TRS). For example, an HVACR system may include a ceiling unit for supplying conditioned air to an air distribution system that includes a duct system. In an HVACR system, conditioned air is delivered to the building or the space it occupies. Summary of the Invention

[0003] The VFD compression efficiency of the compressor, motor, and / or drive is important for the integrated partial load value (IPLV) and energy efficiency ratio (EER) performance of the cooler. In some applications, the main compression inefficiencies arise from the drive, motor, cooler recompression, and / or compressor impeller misalignment due to compressor shaft elongation. The efficiency and / or power losses of each of these interdependent components (motor, drive, compressor, and / or other components of the HVACR system) can compete with each other and may alter the efficiency of the motor and / or drive system.

[0004] Optimization of drive efficiency, motor efficiency, or some combination of both is typically achieved through, for example, pre-programmed lookup tables based on extensive performance modeling and testing. In many VFDs, one approach is to use pulse-width modulation (PWM) mode switching at low speeds relative to high speeds to reduce heating in the VFD, for example. Another approach is to use a motor cooling scheme to control the flow of the working fluid (e.g., refrigerant, etc.) to limit motor heating to predefined limits. The embodiments disclosed herein provide online modification of key inputs (e.g., inverter PWM switching / carrier frequency, inverter PWM switching / carrier mode, motor cooling, drive cooling, etc.) to optimize VFD compression efficiency on the operating graph of the HVACR system.

[0005] A method for adjusting the compression efficiency of an HVACR system with a VFD is disclosed. The method includes: determining a first compression efficiency; determining an operating point; determining a region of an operating graph when the difference between the operating point and a previously determined operating point exceeds a predetermined threshold; adjusting a VFD input to a first input based on the region of the operating graph; and controlling the VFD using the first input for a predetermined time period. The method further includes: determining a second compression efficiency and an operating constraint; adjusting the VFD input to a second input based on the difference between the first and second compression efficiencies and the operating constraint; and controlling the VFD using the second input.

[0006] A VFD-equipped HVACR system is disclosed. The system includes a compressor, a condenser, an expander, and an evaporator fluidly connected. The system also includes a controller. The controller is configured to: determine a first compression efficiency; determine an operating point; determine a region of an operating diagram when the difference between the operating point and a previously determined operating point exceeds a predetermined threshold; adjust the VFD input to a first input based on the region of the operating diagram; and control the VFD using the first input for a predetermined time period. The controller is further configured to: determine a second compression efficiency and an operating constraint; adjust the VFD input to a second input based on the difference between the first and second compression efficiencies and the operating constraint; and control the VFD using the second input.

[0007] The embodiments disclosed herein can also provide a control system for utilizing machine learning control techniques. Multiple system variables can be determined using machine learning control techniques to optimize compression efficiency. Attached Figure Description

[0008] Referring to the accompanying drawings, which form part of this disclosure, and illustrating embodiments in which the systems and methods described in this specification can be implemented.

[0009] Figure 1A This is a schematic diagram of a refrigeration circuit that can be implemented in an HVACR system according to one embodiment.

[0010] Figure 1B This is a perspective view of a climate-controlled transport unit according to one embodiment.

[0011] Figure 1C This is a side view of a truck with a transport climate control system according to one embodiment.

[0012] Figure 2 The illustration shows the first part of a flowchart of a method for adjusting the compression efficiency of an HVACR system with VFD according to an embodiment.

[0013] Figure 3 The second part of a flowchart is illustrated in one embodiment of a method for adjusting the compression efficiency of an HVACR system with VFD.

[0014] Figure 4 The illustration shows a schematic diagram of a machine learning system for adjusting or optimizing the compression efficiency of an HVACR system with VFD, according to one embodiment.

[0015] The same reference numerals denote the same parts throughout. Detailed Implementation

[0016] This disclosure generally relates to optimizing the efficiency of the compression system (e.g., a variable speed compression system) of an HVACR system. More specifically, this disclosure relates to systems and methods for online optimization of the compression system efficiency of an HVACR system with VFD. An HVACR system may include a cooler (e.g., a water cooler, an air-cooled cooler, or any other cooler). In one embodiment, the cooler may include a motor and various types of compressors, electronic device cooling, bearings, air handlers, purifiers, evaporators, condensers, and / or the like.

[0017] Online optimization of VFD compression efficiency is disclosed. Adjustments to key inputs for efficiency and / or power loss management (e.g., inverter PWM switching / carrier frequency, inverter PWM switching / carrier mode, motor cooling and / or driver cooling, etc.) can be made in real-time during HVACR system operation to achieve optimal VFD compression system efficiency (e.g., kW / Ton, etc.) while independently applying limiting / constraint criteria such as inverter thermal limits, motor thermal limits, shaft clearance, etc.

[0018] The following definitions apply throughout this disclosure. As defined herein, the term "kW / ton" can refer to the ratio of power input rate (kW, kilowatts) to heat removal rate in tons of refrigeration (tons) (1 ton of refrigeration equals 12,000 Btu / hour). It should be understood that kW / ton can be a measure of efficiency, which is equal to power extraction (kW) divided by cooling consumption (tons of refrigeration). A lower value of kW / ton corresponds to improved efficiency (e.g., compression efficiency or cooler efficiency, etc.). In other words, a lower kW / ton means that the unit is more efficient.

[0019] The terms “compression efficiency,” “compression system efficiency,” or “cooler efficiency” can refer to efficiency expressed in kW / ton (e.g., for large commercial and / or industrial air conditioning, heat pumps, refrigeration systems, and / or other suitable systems), by energy efficiency ratio (EER, e.g., for cooling energy efficiency in, for example, integrated air conditioning and / or heat pump systems or other suitable systems), by European seasonal energy efficiency ratio (ESEER), or any other suitable energy performance rating.

[0020] The term "variable frequency drive" or "VFD" can refer to a type of motor drive that controls the speed and torque of an AC motor by changing the motor input frequency and voltage. In one embodiment, PWM can be used to change the motor voltage (or current) and frequency of the drive. The VFD drive (e.g., an inverter) can drive the motor, and the motor can drive a compressor (e.g., a variable speed compressor).

[0021] The term "machine learning" may refer to applications of artificial intelligence (AI), which provides systems with the ability to learn automatically and improve from experience without being explicitly programmed. Machine learning focuses on the development of computer programs that can access and use data to learn on their own. Machine learning algorithms build "trained machine learning models" based on sample data (called "training data") to make predictions or decisions without being explicitly programmed.

[0022] Specific embodiments of this disclosure are described herein with reference to the accompanying drawings; however, it should be understood that the disclosed embodiments are merely examples of this disclosure and may be implemented in various different forms. Well-known functions or constructions have not been described in detail to avoid obscuring this disclosure with unnecessary detail. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but only as a basis for the claims and as a representative basis for teaching those skilled in the art to use this disclosure differently with virtually any suitably detailed structure. In this specification and the drawings, similar reference numerals denote elements that can perform the same, similar, or equivalent functions.

[0023] Furthermore, this disclosure can be described herein in terms of functional block components and various different processing steps. It should be understood that such functional blocks can be implemented by any number of hardware and / or software components configured to perform specified functions. For example, this disclosure can employ various different integrated circuit components, such as memory elements, processing elements, logic elements, lookup tables, etc., which can perform various different functions under the control of one or more microprocessors or other control devices.

[0024] The scope of this disclosure should be determined by the appended claims and their legal equivalents, and not by the examples given herein. For example, the steps recited in any method claim may be performed in any order, and are not limited to the order presented in the claims. Furthermore, unless specifically described herein as “critical” or “essential,” no element is essential for the practice of this disclosure.

[0025] Figure 1A This is a schematic diagram of a refrigerant circuit 100 according to one embodiment. The refrigerant circuit 100 generally includes a compressor 120, a condenser 140, an expansion device 160, and an evaporator 180. The term "expansion device" as described herein may also be referred to as an expander. In one embodiment, the expander may be an expansion valve, expansion plate, expansion container, orifice, or other expansion mechanism of this type. It should be understood that the expander may be any suitable type of expander used in the art for expanding a working fluid to reduce the pressure and temperature of that working fluid. The refrigerant circuit 100 is an example and may be modified to include additional components. For example, in one embodiment, the refrigerant circuit 100 may include other components such as, but not limited to: an economizer heat exchanger, one or more flow control devices, a receiver tank, a dryer, a suction liquid heat exchanger, one or more fans, one or more filters, one or more dampers, etc.

[0026] Refrigerant circuit 100 can typically be used in various systems for controlling environmental conditions (e.g., temperature, humidity, air quality, etc.) in a space (often referred to as the conditioned space). Examples of such systems include, but are not limited to, HVACR systems including transport refrigeration systems. In one embodiment, an HVACR system may include a ceiling unit or a heat pump air conditioning unit.

[0027] Compressor 120, condenser 140, expander 160, and evaporator 180 are fluidly connected. In one embodiment, refrigerant circuit 100 can be configured as a cooling system (e.g., an air conditioning system) capable of operating in a cooling mode. In one embodiment, refrigerant circuit 100 can be configured as a heat pump system capable of operating in both cooling and heating / defrosting modes. One or more fans can be provided to heat exchangers, such as condenser 140 and / or evaporator 180.

[0028] The refrigerant circuit 100 can operate according to generally known principles. The refrigerant circuit 100 can be configured to heat and / or cool a liquid process fluid (e.g., a heat transfer fluid or medium (e.g., a liquid, such as but not limited to water)), in which case the refrigerant circuit 100 can typically represent a liquid cooler system. Alternatively, the refrigerant circuit 100 can be configured to heat and / or cool a gaseous process fluid (e.g., a heat transfer medium or fluid (e.g., a gas, such as but not limited to air)), in which case the refrigerant circuit 100 can typically represent an air conditioner and / or a heat pump.

[0029] During operation, compressor 120 compresses a working fluid (e.g., a heat transfer fluid, such as a refrigerant) from a relatively low-pressure gas to a relatively high-pressure gas. This relatively high-pressure gas is also at a relatively high temperature. This relatively high-pressure gas is discharged from compressor 120 and flows through condenser 140. According to generally known principles, the working fluid flows through condenser 140 and dissipates heat to the process fluid (e.g., water, air, etc.), thereby cooling the working fluid. The cooled working fluid, now in liquid form, flows to expansion device 160. Expansion device 160 reduces the pressure of the working fluid. As a result, a portion of the working fluid is converted to a gaseous form. The working fluid, now in a mixed liquid and gaseous form, flows to evaporator 180. The working fluid flows through evaporator 180 and absorbs heat from the process fluid (e.g., a heat transfer medium, such as water, air, etc.), thereby heating the working fluid and converting it to a gaseous form. The gaseous working fluid then returns to compressor 120. When the heat transfer circuit is in operation, such as when it is in cooling mode (e.g., when compressor 120 is activated), the process described above continues.

[0030] Figure 1B This is a perspective view of a climate-controlled transport unit 20 that can be attached to a tractor 55 according to one embodiment. The climate-controlled transport unit 20 includes a transport climate control system 10 for a transport unit 15. The tractor 55 is attached to the transport unit 15 and configured to tow the transport unit 15. Figure 1B The transport unit 15 shown is a trailer.

[0031] The transport climate control system 10 includes a climate control unit (CCU) 20 that provides environmental control (e.g., temperature, humidity, air quality, etc.) within the climate-controlled space 25 of the transport unit 15. The CCU 20 is disposed on the front wall 30 of the transport unit 15. In other embodiments, it should be understood that the CCU 20 may be disposed, for example, on the ceiling or another wall of the transport unit 15. The CCU 20 includes a cooling circuit (see example...). Figure 1AThe refrigeration circuit connects, for example, a compressor, a condenser, an evaporator, and an expansion device to provide conditioned air within the climate-controlled space 25. In one embodiment, CCU20 may be a transport refrigeration unit.

[0032] The transport climate control system 10 also includes a programmable climate controller 35 and one or more sensors (not shown) configured to measure one or more parameters of the transport climate control system 10 (e.g., ambient temperature outside the transport unit 15, ambient humidity outside the transport unit 15, compressor suction pressure, compressor discharge pressure, supply air temperature of air supplied from the CCU 20 to the climate-controlled space 25, return air temperature of air returning from the climate-controlled space 25 to the CCU 20, humidity within the climate-controlled space 25, etc.) and transmit climate control data to the climate controller 35. The one or more climate control sensors may be located at various different locations outside the transport unit 20 and / or inside the transport unit 20 (including within the climate-controlled space 25).

[0033] Climate controller 35 is configured to control the operation of transport climate control system 10, including components of a climate control loop. Climate controller 35 may include a single integrated control unit 40, or a distributed network of climate controller elements 40, 45. The number of control elements distributed in a given network may depend on the specific application of the principles described herein. Measured parameters obtained from one or more climate control sensors can be used by climate controller 35 to control the operation of the climate control system 10.

[0034] The climate-controlled transport unit 20 includes independent sensors 50. In the illustrated embodiment, the independent sensor 50 is represented as a single sensor. It should be understood that in other embodiments, the climate-controlled transport unit 20 may include multiple independent sensors 50. In some embodiments, the independent sensor 50 is a dedicated control sensor that can provide independent verification of climate control parameters (e.g., temperature, humidity, atmosphere, etc.) within the climate-controlled space 25. The independent sensor 50 is not used by the climate controller 35 to control the operation of the transport climate control system 10. The independent sensor 50 communicates electronically with the power source (not shown) of the CCU 20. In one embodiment, the independent sensor 50 communicates electronically with the climate controller 35. It should be understood that the electronic communication between the independent sensor 50 and the climate controller 35 enables network communication of parameters measured by the independent sensor 50 or sensed verification values ​​(e.g., temperature data of goods stored in the climate-controlled space 25). The electronic communication between the climate controller 35 and the independent sensor 50 prevents the sensed verification values ​​or parameters from being used in the control of the CCU 20.

[0035] Figure 1C This is a side view of a truck 11 having a transport climate control system 14 according to an embodiment. Figure 1C A climate-controlled truck 11 is depicted, which includes a transport climate control system 14 and a climate-controlled space 16 for transporting goods.

[0036] The transport climate control system 14 includes a climate control unit (CCU) 13, which is mounted to the front wall 17 of the climate-controlled space 16. The CCU 13 may include a cooling circuit (see, for example, [link to relevant documentation]). Figure 1A The refrigeration circuit includes, among other components, such as a compressor, condenser, evaporator, and expansion unit, to provide climate control within the climate-controlled space 16. In one embodiment, the CCU 13 may be a transport refrigeration unit.

[0037] The transport climate control system 14 also includes a programmable climate controller 19 and one or more climate control sensors (not shown) configured to measure one or more parameters of the transport climate control system 14 (e.g., ambient temperature outside the truck 11, ambient humidity outside the truck 11, compressor suction pressure, compressor discharge pressure, supply air temperature of air supplied from the CCU 13 to the climate-controlled space 16, return air temperature of air returning from the climate-controlled space 16 to the CCU 13, humidity within the climate-controlled space 16, etc.) and transmit climate control data to the climate controller 19. The one or more climate control sensors may be located at various different locations outside the truck 11 and / or inside the truck 11 (including within the climate-controlled space 16).

[0038] Climate controller 19 is configured to control the operation of transport climate control system 14, which includes components of a climate control loop. Climate controller 19 may include a single integrated control unit 19, or a distributed network that may include climate controller elements 19, 12. The number of control elements distributed in a given network may depend on the specific application of the principles described herein. Measured parameters obtained from one or more climate control sensors may be used by climate controller 19 to control the operation of the climate control system 14.

[0039] Truck 11 includes an independent sensor 18. In the illustrated embodiment, the independent sensor 18 is shown as a single sensor. It should be understood that in other embodiments, truck 11 may include multiple independent sensors 18. In some embodiments, the independent sensor 18 is a dedicated control sensor that can provide independent verification of climate control parameters (e.g., temperature, humidity, atmosphere, etc.) within the climate-controlled space 16. The independent sensor 18 is not used by the climate controller 19 for controlling the operation of the transport climate control system 14. The independent sensor 18 communicates electronically with the power source (not shown) of the CCU 13. In one embodiment, the independent sensor 18 communicates electronically with the climate controller 19. It should be understood that the electronic communication between the independent sensor 18 and the climate controller 19 enables network communication of parameters measured by the independent sensor 18 or sensed verification values ​​(e.g., temperature data of cargo stored in the climate-controlled space 16). The electronic communication between the climate controller 19 and the independent sensor 18 prevents the sensed verification values ​​or parameters from being used in the control of the CCU 13.

[0040] Figure 2 The first part 200 of the flowchart illustrates a method for adjusting or optimizing the compression efficiency of an HVACR system with VFD according to an embodiment.

[0041] Figure 3 The second part 300 of the flowchart illustrates a method for adjusting or optimizing the compression efficiency of an HVACR system with VFD according to an embodiment.

[0042] The flowcharts (200, 300) of operation or processing may include one or more operations, actions, or functions depicted by one or more boxes 210, 220, 230, 240, 250, 260, 270, 280, 290, 310, 320, 330, 340, 350, 360, 370, and 380. Although illustrated as discrete boxes, various different boxes may be divided into additional boxes, combined into fewer boxes, or eliminated, depending on the desired implementation. As a non-limiting example, the operation may be performed by one or more controllers (e.g., ...) described herein. Figure 1B Controller 35 Figure 1C The controller (such as controller 19) or any other suitable controller(s) having, for example, a processor and / or memory executes the blocks of the flowchart (200, 300). The flowchart (200, 300) may begin at block 210.

[0043] Box 210 may refer to a method by which the controller begins to adjust or optimize the compression efficiency of an HVACR system with a VFD. In one embodiment, at 210, components of the HVACR system may begin to run and / or operate, and the controller may perform initialization steps to initialize the HVACR system. In another embodiment, prior to 210, components of the HVACR system may begin to run and / or operate, the controller may perform initialization steps to initialize the HVACR system, and at 210, the controller may begin a method for adjusting or optimizing compression efficiency. Box 210 may be followed by box 220.

[0044] Box 220 may indicate that the controller determines a first compression efficiency. In one embodiment, the compression efficiency can be expressed in kW / ton. In another embodiment, the compression efficiency can be expressed by EER, SEER, ESEER, or any other energy-appropriate performance level or standard.

[0045] In one embodiment, the input power (kW) to the HVACR system (e.g., to drives, motors, compressors, other electronic devices, etc.) can be measured or sensed by, for example, one or more sensors of the HVACR system (such as one or more current sensors, voltage sensors, one or more power meters (e.g., installed in a circuit breaker), etc.). The measured kW can be transmitted to, and / or obtained by, the controller, and / or stored in a memory or data recording device.

[0046] In one embodiment, the controller can determine the heat extraction or cooling capacity (refrigeration tons) of components of the HVACR system (e.g., evaporators, condensers, etc.) based on, for example, the temperature of the process fluid (e.g., water, air, etc.), ΔT (e.g., the difference between the temperature of the return process fluid and the temperature of the discharge process fluid for process fluid flowing out of and / or into evaporator coils, condenser coils, etc.), process fluid flow rate, etc. One or more temperatures and / or flow rates can be measured or sensed, for example, by one or more sensors of the HVACR system. The measured temperatures and / or flow rates can be transmitted to the controller, and / or obtained by the controller, and / or stored in a memory or data recording device.

[0047] In one embodiment, the controller may determine a first compression efficiency based on the measured input power (kW) and the determined cooling capacity (refrigeration tons). Box 220 may be followed by box 230.

[0048] Box 230 may refer to the controller determining the operating point. In one embodiment, the operating point may be determined by, for example, HVACR system needs or requirements (such as how many tons of cooling are needed), process fluid temperature setpoint, return process fluid temperature to the evaporator, discharge process fluid temperature used to cool the condenser, etc., in order to determine what the compressor can do (e.g., increase or decrease capacity, increase and / or decrease compressor and / or motor speed, etc.). Thus, the operating point may be determined by one or more operating parameters, such as the temperature and / or flow rate of the incoming process fluid, the ambient temperature of the process fluid, the refrigerant pressure, compressor speed, discharge and / or suction pressure, process fluid temperature setpoint, etc. In one embodiment, the operating point may be determined by considering, for example, switching frequency / mode, motor speed, trade-offs in motor cooling, etc. Box 230 may be followed by box 240.

[0049] Box 240 may refer to the controller determining whether the operating point has changed significantly (e.g., the difference between the operating point determined at box 230 and a previously determined operating point exceeds a predetermined threshold). For example, when the operating point includes compressor speed, the compressor speed is considered to have changed significantly if the difference between the compressor speed determined at box 230 and a previously determined compressor speed exceeds a predetermined threshold (e.g., a change in compressor speed equal to or approximately 10%). In another example, when the operating point includes load (e.g., current), the load is considered to have changed significantly if the difference between the load determined at box 230 and a previously determined load exceeds a predetermined threshold (e.g., a change in load equal to or approximately 10%). It should be understood that the predetermined threshold can be defined as a value that changes the operating conditions of the HVACR system compared to the system design under which the HVACR system typically operates (e.g., with a system variation of equal to or approximately 2% to equal to or approximately 3% when (one or more) controllers perform regulation).

[0050] In one embodiment, the previously determined operating point may be an operating point determined by the controller at or before block 210.

[0051] When the operating point changes significantly, box 240 can be followed by box 250. When the operating point does not change significantly, box 240 can be followed by box 260, and the operating point at box 230 can be stored by the controller as a previously determined operating point (e.g., stored in memory, a data recording device, etc.) for the next comparison iteration. In other words, for a steady state (e.g., the operating point does not change significantly), the embodiments disclosed herein can find and achieve the optimized compression efficiency by checking whether the compression efficiency is improved in each iteration until no further improvement in compression efficiency can be obtained.

[0052] Box 250 may refer to the controller discarding the compression efficiency determined at box 220 and the operating point determined at box 230, and returning to box 210. It should be understood that the connector B (see also...) Figure 3 The loop also returns to box 210.

[0053] In another embodiment, when the operating point does not change significantly, block 240 may be followed by block 265 (instead of block 260), and the operating point at block 230 may be stored by the controller as a previously determined operating point (e.g., stored in memory, a data recording device, etc.) for the next comparison iteration. In such an embodiment, block 265 (see [link to detailed description]) Figure 4 The ) can be followed by a connector C, which connects to... Figure 3 The frame is 340.

[0054] Box 260 may refer to the controller determining the operating diagram of the HVACR system. In one embodiment, the operating diagram may include three regions: (Region 1) low speed (e.g., compressor speed, motor speed, etc.) and low lift; (Region 2) medium speed; and (Region 3) high speed and high lift. In one embodiment, the low speed region may be a region of the operating diagram in which the speed (e.g., compressor speed, motor speed, etc.) ranges from equal to or about 25% of the maximum speed to equal to or about 50% of the maximum speed. The medium speed region may be a region of the operating diagram in which the speed ranges from equal to or about 50% of the maximum speed to equal to or about 75% of the maximum speed. The high speed region may be a region of the operating diagram in which the speed ranges from equal to or about 75% of the maximum speed to equal to or about 100% of the maximum speed. The low lift region may be a region of the operating diagram in which the lift is equal to or less than 150 pounds per square inch difference (PSID). The high lift region may be a region of the operating diagram in which the lift is equal to or greater than 150 PSID. In another embodiment, the operation diagram may include fewer or more than three regions.

[0055] In one embodiment, the speed (e.g., of a compressor, etc.) can be measured or sensed by, for example, one or more sensors in an HVACR system. The measured speed can be transmitted to, and / or obtained by, the controller, and / or stored in a memory or data recording device. Lift can be defined as the pressure difference between the evaporator and the condenser (e.g., the difference in refrigerant pressure between the evaporator and the condenser). One or more pressures can be measured or sensed by, for example, one or more sensors in an HVACR system. The measured pressures can be transmitted to, and / or obtained by, the controller, and / or stored in a memory or data recording device. Lift can indicate how much work the compressor needs to do to raise the pressure from the evaporator pressure to the condenser pressure. Typically, lower speed and / or lift can indicate a lower cooling capacity (refrigeration tons).

[0056] When the operation diagram is in region 1, box 260 can be followed by box 270. When the operation diagram is in region 2, box 260 can be followed by box 280. When the operation diagram is in region 3, box 260 can be followed by box 290.

[0057] Box 270 may refer to the controller adjusting the inverter PWM switching (or carrier) frequency (e.g., the PWM frequency of a VFD driver, which can range from a minimum permissible frequency (e.g., equal to or approximately 6 kHz) to a maximum permissible frequency (e.g., equal to or approximately 12 kHz)). Adjusting the PWM frequency may include increasing or decreasing the PWM frequency by a predetermined amount (e.g., an amount equal to or approximately 0.5 kHz, or an amount equal to or approximately 1 kHz) or percentage. In one embodiment, in a first iteration of the method, the PWM frequency may be decreased by a predetermined amount or percentage. In another embodiment, in a first iteration of the method, the PWM frequency may be increased by a predetermined amount or percentage. Box 270 may be followed by a connection to... Figure 3 The connector A in box 310.

[0058] Box 280 may refer to the controller adjusting the inverter's PWM switching (or carrier) mode (e.g., the PWM mode of a VFD driver). Adjusting the PWM mode may include switching the PWM mode to a first mode or a second mode. In one embodiment, the first mode may be a discontinuous PWM drive waveform mode, while the second mode may be a continuous (e.g., a smooth sine wave) PWM drive waveform mode. In one embodiment, the PWM mode may be switched to the first mode in a first iteration of the method. In another embodiment, the PWM mode may be switched to the second mode in a first iteration of the method. Box 280 may be followed by a connector A.

[0059] Box 290 may refer to the controller adjusting motor cooling. Adjusting motor cooling may include increasing or decreasing the amount of working fluid (e.g., coolant, etc.) supplied to the motor (for cooling the motor) by a predetermined amount or percentage (e.g., an adjustment ranging from equal to or about 5% to equal to or about 10%). In one embodiment, in a first iteration of the method, motor cooling may be increased by a predetermined amount or percentage (e.g., as a conservative starting point (e.g., overcooling) to avoid overheating the motor). In another embodiment, in a first iteration of the method, motor cooling may be decreased by a predetermined amount or percentage. It should be understood that motor cooling requirements may be determined by the motor load, and / or drive switching frequency and / or mode, etc. More cooling of the motor may mean more compressor or system losses (e.g., power losses, and / or efficiency losses, etc.) because the compressor may recompress the working fluid used to cool the motor, and the recompression cycle may be a system loss. The amount of cooling to the motor (e.g., the working fluid from the compression cycle, or any other suitable means of cooling the motor) needs to be controlled or minimized (e.g., by controlling a control valve for the working fluid, such as an expansion valve) in order to minimize system losses, and the amount of cooling to the motor needs to be sufficient to cool the motor to prevent it from overheating. A connector A may follow box 290.

[0060] It should be understood that there may be boxes corresponding to one or more other areas of the operation diagram. Such boxes may refer to controller adjustments of drive cooling or other system variables, and such boxes follow box 260, which may be followed by connector A.

[0061] like Figure 3 In the diagram, the connector A may be followed by box 310. Box 310 may refer to the controller using adjusted inputs from 270, 280, or 290 to control the VFD for a predetermined time period (e.g., equal to or approximately 60 seconds), determining a second compression efficiency (see also box 220), and / or determining whether the compression efficiency has been improved by comparing the first compression efficiency and the second compression efficiency. For example, when using kW / ton, if the second kW / ton is less than the first kW / ton, the compression efficiency is improved. In one embodiment, determining whether the compression efficiency has been improved includes: (1) determining whether the compression efficiency has been improved; and (2) determining whether the difference between the first compression efficiency and the second compression efficiency exceeds a predetermined threshold. In such an embodiment, if the compression efficiency is improved and the difference exceeds the predetermined threshold, the compression efficiency is considered to be improved. If the compression efficiency is not improved, or the compression efficiency is improved but the difference does not exceed the predetermined threshold, the compression efficiency is considered not improved.

[0062] When compression efficiency is improved, box 310 can be followed by box 320. When compression efficiency is not improved, box 310 can be followed by box 330.

[0063] Box 320 may refer to the controller proposing a change that is the same as or similar to one or more changes last made (e.g., in boxes 270, 280, or 290, depending on the area of ​​the operating diagram). For example, if the last change(s) was reducing the PWM frequency by a predetermined amount or percentage (see box 270), the controller may be configured to propose reducing the PWM frequency by the predetermined amount or percentage again. If the last change(s) was increasing the PWM frequency by a predetermined amount or percentage (see box 270), the controller may be configured to propose increasing the PWM frequency by the predetermined amount or percentage again. If the last change(s) was switching the PWM mode to a first mode (see box 280), the controller may be configured to propose maintaining the first mode. If the last change(s) was switching the PWM mode to a second mode (see box 280), the controller may be configured to propose maintaining the second mode. If the last change(s) made was to increase motor cooling by a predetermined amount or percentage (see box 290), the controller can be configured to propose to increase motor cooling by the predetermined amount or percentage again. If the last change(s) made was to decrease motor cooling by a predetermined amount or percentage (see box 290), the controller can be configured to propose to decrease motor cooling by the predetermined amount or percentage again. Box 320 may be followed by box 340.

[0064] Box 330 may refer to the controller proposing one or more changes opposite to (for example, in boxes 270, 280, or 290, depending on the area of ​​the operating diagram) the changes (one or more) last made. For example, if the last change (one or more) was to reduce the PWM frequency by a predetermined amount or percentage (see box 270), the controller may be configured to propose to increase the PWM frequency by a predetermined amount or percentage. If the last change (one or more) was to increase the PWM frequency by a predetermined amount or percentage (see box 270), the controller may be configured to propose to decrease the PWM frequency by a predetermined amount or percentage. If the last change (one or more) was to switch the PWM mode to a first mode (see box 280), the controller may be configured to propose to switch the PWM mode to a second mode. If the last change (one or more) was to switch the PWM mode to a second mode (see box 280), the controller may be configured to propose to switch the PWM mode back to the first mode. If the last change(s) made was to increase motor cooling by a predetermined amount or percentage (see box 290), the controller can be configured to propose to again decrease motor cooling by a predetermined amount or percentage. Box 330 may be followed by box 340.

[0065] Box 340 may refer to the controller applying or checking a first limitation or operational constraint (shaft elongation constraint). The shaft elongation (of the compressor) can be measured or sensed by, for example, one or more sensors in an HVACR system (such as one or more position sensors). The measured shaft elongation can be transmitted to the controller, and / or acquired by the controller, and / or stored in memory or a data logging device. When the shaft elongation exceeds a predetermined threshold (e.g., a threshold that can prevent mechanical damage to one or more compression elements), the controller is configured to disallow increased motor heating (e.g., disallowing a reduction in the PWM frequency or a reduction in motor cooling). It should be understood that the impeller may be located at a position along the length of the shaft, and misalignment of the impeller may exist when the shaft expands or contracts, which can affect the flow of working fluid exiting the impeller, potentially impacting performance. Box 340 may be followed by box 350.

[0066] Box 350 may refer to the controller applying or checking a second limitation or operational constraint (motor temperature constraint). Motor temperature can be measured or sensed by, for example, one or more sensors (e.g., one or more temperature sensors) in an HVACR system. The measured motor temperature can be transmitted to the controller, and / or acquired by the controller, and / or stored in memory or a data logging device. When the motor temperature exceeds a predetermined threshold (e.g., a threshold not exceeding the physical limitations of the motor components), the controller is configured to disallow increased motor heating (e.g., disallowing a reduction in the PWM frequency or a decrease in motor cooling). It is understood that the motor temperature threshold can be determined based on, for example, the insulation level of the stator windings. Box 350 may be followed by box 360.

[0067] Box 360 may refer to the controller applying or checking a third limitation or operational constraint (drive temperature constraint). The drive temperature (which may differ from the motor temperature) can be measured or sensed by, for example, one or more sensors (e.g., one or more temperature sensors) in an HVACR system. The measured drive temperature can be transmitted to the controller, and / or acquired by the controller, and / or stored in memory or a data recording device. When the drive temperature exceeds a predetermined threshold (e.g., a threshold equal to or approximately 150 degrees Celsius, the temperature of the junction for a silicon (Si) insulated gate bipolar transistor (IGBT), the controller is configured to disallow further drive heating (e.g., disallow an increase in the PWM frequency). Box 360 may be followed by box 370.

[0068] It should be understood that the order of blocks 340, 350, and / or 360 can be changed. For example, the order could be 340→350→360, 340→360→350, 350→340→360, 350→360→340, 360→340→350, or 360→350→340. It should also be understood that in one embodiment, one or more limitations / constraints as described in blocks 340, 350, and / or 360 may be present. In another embodiment, in addition to those limitations / constraints described in blocks 340, 350, and / or 360, other limitations / constraints may exist depending on the desired implementation.

[0069] Box 370 may refer to the controller applying (in box 320 or 330) the proposed change. If no constraints are applied / enforced from boxes 340, 350, and / or 360, the controller is configured to apply / perform (in box 320 or 330) the proposed change. If constraints are applied / enforced in boxes 340, 350, and / or 360, the proposed change (in box 320 or 330) may be applied based on one or more constraints applied / enforced in boxes 340, 350, and / or 360 (e.g., disallowing certain changes). Box 370 may be followed by box 380.

[0070] Box 380 may refer to the controller using the changes applied in box 370 to control the VFD and / or HVACR system for a predetermined period of time (e.g., equal to or approximately 60 seconds) so that the effects of the applied changes occur before the next iteration. Box 380 may be followed by connector B. Connector B can connect to... Figure 2 Box 210 is used to begin the next iteration of the search for methods to optimize compression efficiency.

[0071] In one embodiment, the method disclosed herein requires a time period (e.g., equal to or approximately 60 seconds) for each iteration because it may take up to that time period for (e.g., due to adjustments to VFD inputs, etc.) changes to the temperature, pressure, etc., that need to be reflected in the HVACR system. In other words, for each iteration, how the system operated at a previous time period (previous operating point) is compared with how the system operates at the current time (current operating point), and the method takes at least that time period to find or achieve optimized compression efficiency.

[0072] The embodiments disclosed herein provide a method for dynamically learning compression efficiency and / or operating point, etc., from system inputs, changing VFD inputs, and adapting to that change over a period of time (e.g., during the daytime). For example, an HVACR system may produce more cooling during the daytime (when the cooler is operating at a higher load) than in the morning or at night (when the cooler is operating at a lower load), meaning the HVACR may change from a steady state (low / medium / high cooling) to another state (e.g., from morning to daytime, from daytime to nighttime, etc.). Once the state changes (e.g., from a cooling capacity of approximately 400 refrigeration tons in the morning to approximately 600 refrigeration tons during the daytime, where the cooler may ramp up to that capacity in approximately 30 minutes to approximately one hour), the method disclosed herein can be initiated. At the end of the daytime, the change can be reversed (e.g., from a cooling capacity of approximately 600 refrigeration tons during the day to approximately 400 refrigeration tons at night), and the method disclosed herein can be initiated whenever the state changes. In other words, for steady-state conditions (e.g., when the operating point does not change significantly, such as in the morning, during the day, or at night), the embodiments disclosed herein can find and achieve optimized compression efficiency.

[0073] If compression efficiency has not been optimized in previous (one or more) iterations, the method disclosed herein can learn from rules or inputs to optimize compression efficiency, and settings or VFD inputs can be changed while the system is running in an operational graph to determine further improvements in compression efficiency.

[0074] Figure 4 The illustration shows an embodiment. Figure 2 Method 265 is a schematic diagram of a machine learning system for adjusting or optimizing the compression efficiency of an HVACR system with VFD. It should be understood that Method 265 can be added to or can replace... Figure 2 The frames 260, 270, 280, 290 and Figure 3 Boxes 310, 320, and 330 are used as alternative embodiments.

[0075] In other words, in Figure 2 In the context of the operation point not changing significantly, box 240 can be followed by box 265 (instead of box 260), and box 265 can be followed by a connection to... Figure 3 The connector C in box 340.

[0076] Method 265 may include one or more operations, actions, or functions 420. As a non-limiting example, it may be performed by one or more controllers (e.g., [controllers described herein]). Figure 1B Controller 35 Figure 1CMethod 265 may be performed by a controller (such as controller 19) or any other suitable controller(s) having, for example, a processor and / or memory. Method 265 may deploy, for example, a trained machine learning model (e.g., a compression efficiency model) to determine system variables (e.g., inverter PWM switching / carrier frequency, inverter PWM switching / carrier mode, motor cooling, driver cooling, etc.).

[0077] like Figure 4 As shown, method 265 includes using parameters such as motor speed (e.g., revolutions per minute (N)). PRM Inputs 410, such as load, one or more changes (ΔkW / Ton) expressed in kW / Ton, etc., are provided to the trained compression efficiency model. The operation of the trained compression efficiency model (e.g., via a controller) can provide outputs 430, such as the determination or setpoint of system variables (e.g., inverter PWM switching / carrier frequency, inverter PWM switching / carrier mode, motor cooling, drive cooling, and / or similar system variables), to determine the compression efficiency model after applying constraints (e.g., boxes 340, 350, and / or 360). Figure 3 The application is located at box 370.

[0078] It should be understood that method 265 may include step 420, such as the controller creating a machine learning model (e.g., a compression efficiency model). The compression efficiency model may be stored in, for example, memory or any other suitable device.

[0079] It should be understood that method 265 may also include step 420, for example, where the controller uses data from the HVACR system to train a compression efficiency model. The data may include, but is not limited to: input power (kW), heat extraction or cooling capacity (tons of refrigeration), process fluid temperature, ΔT, and / or any one or more of the process fluid flow rate from box 220. The data may also include operating point, HVACR system requirements or demands, process fluid temperature setpoint, return process fluid temperature to the evaporator, discharge process fluid temperature for cooling the condenser, compressor capacity, compressor and / or motor speed, temperature and / or flow rate of the incoming process fluid, ambient temperature of the process fluid, refrigerant pressure, and / or discharge and / or suction pressure from box 230. The data may also include speed and / or lift from box 260, PWM frequency from box 270, PWM mode from box 280, and / or amount of motor cooling from box 290. It should be understood that methods for achieving, such as... Figure 2 and Figure 3 The optimized compression efficiency of data and / or processes described herein is used to facilitate training.

[0080] It should be understood that method 265 may also include step 420, such as deploying the trained compression efficiency model to the controller for use. For example, the trained compression efficiency model may be deployed to the controller of an HVACR system in the art for use.

[0081] It should be understood that the type and / or source of the data used to run the trained compression efficiency model (i.e., field data from the HVACR system when the HVACR system is running) can be similar to the type and / or source of the data used to train the compression efficiency model (i.e., data based on experience, tests, etc.).

[0082] It should be understood that method 265 may also include step 420, for example, the controller retraining the compression efficiency model using updated or new training data.

[0083] It is understandable that other different VFD controls may exist. For example, a higher predetermined PWM switching frequency may be used for partial load, and a lower predetermined PWM switching frequency may be used for full load (e.g., to save driver losses). Lookup tables (one or more) may also be used.

[0084] The embodiments disclosed herein can provide performance benefits, such as improved VFD compression efficiency, especially under partial load conditions that are difficult to model and predict. The embodiments disclosed herein can provide development benefits, such as reducing the amount of system modeling and testing required to identify peak system performance during the development phase, and reducing errors in modeling. Because compression efficiency (e.g., kW / ton, etc.) is measured in real time while the HVACR system is running, the methods disclosed herein can naturally respond to the effects of aging of components of the HVACR system (e.g., drives, motors, compressors, etc.), such as motors, drives, compressors, etc., which may become less robust due to aging, may overheat several times, and may become less efficient than when newer, the workpiece of the specific component built during manufacturing, variations in workpiece (e.g., more / less weakening on windings, harder / easier cooling, etc.), variant components (motors, drives, compressors, etc.) in the HVARC system, untested portions of the operating diagram, etc., on efficiency.

[0085] Compared to static settings (e.g., using a PWM frequency of, for example, 8 kHz, discontinuous switching modes from driver to motor, a motor that generates a certain amount of heat and requires a certain amount of cooling, etc.), the embodiments disclosed herein can provide dynamic performance improvements, especially for partial loads.

[0086] The embodiments disclosed herein can be applied to motors driven by VFDs, where multiple competing trade-offs exist between interdependent motor and / or drive losses and the mechanical efficiency of the driven shaft. It is understood that trade-offs can exist, for example, between the motor and the drive (e.g., drive efficiency relative to motor cooling). For instance, if the motor obtains a smooth sinusoidal (continuous) waveform pattern and a high switching frequency from the drive, the motor can operate more efficiently. However, the drive may need to do a significant amount of work to produce the high switching frequency and / or continuous waveform, meaning the drive may be less efficient. When the motor is less efficient (while the drive is more efficient), the motor may get hotter and require more cooling (meaning more losses and / or lower efficiency in terms of compression efficiency). When the motor is more efficient (while the drive is less efficient), the motor may get colder and require less cooling (meaning higher compression efficiency). In other words, there may be many interconnected or interdependent components or parts of an HVACR system that may compete with each other, making one component potentially more efficient while another is less efficient. Modeling the most efficient way to operate an HVACR system can be difficult. The embodiments disclosed herein can use measurement results that indicate whether the compression efficiency of an HVACR system is moving in the right direction, and settings or inputs can be changed online to achieve optimized compression efficiency.

[0087] It should also be understood that in one or more permanent magnet (PM) motors, a relationship can exist between the PWM frequency and motor and / or driver losses, and a trade-off exists between reducing motor heating and compression efficiency losses due to motor cooling. Tests have been performed, and data demonstrate this causal relationship. Synthetic data show that compression efficiency (e.g., kW / ton, etc.) relative to PWM frequency / mode and motor cooling can be obtained, for example, at different load lines, pressure ratios, etc. The embodiments disclosed herein allow for continuous modification of the PWM frequency / mode and motor cooling to optimize compression efficiency (e.g., kW / ton, etc.).

[0088] Multiple aspects:

[0089] It should be understood that any one of aspects 1 to 9 can be combined with any one of aspects 10 to 20, and any one of aspects 10 to 19 can be combined with aspect 20.

[0090] Aspect 1. A method for adjusting the compression efficiency of a heating, ventilation, air conditioning, and refrigeration (HVACR) system having a variable frequency drive (VFD), the method comprising:

[0091] The first compression efficiency is determined by the controller;

[0092] The operating point is determined by the controller;

[0093] When the difference between the operation point and the previously determined operation point exceeds a predetermined threshold, the area of ​​the operation diagram is determined;

[0094] Based on the region of the operation diagram, the VFD input is adjusted to the first input;

[0095] The first input is used to control the VFD to continue for a predetermined period of time;

[0096] Determine the second compression efficiency and operational constraints;

[0097] The VFD input is adjusted to the second input based on the difference between the first compression efficiency and the second compression efficiency and the operational constraints; and

[0098] The VFD is controlled using the second input.

[0099] Aspect 2. The method according to aspect 1, wherein determining the first compression efficiency includes determining a first kW / Ton,

[0100] Determining the second compression efficiency includes determining the second kW / Ton.

[0101] Aspect 3. The method according to aspect 1, wherein determining the first compression efficiency includes determining a first energy performance level.

[0102] Determining the second compression efficiency includes determining the second energy performance level.

[0103] Aspect 4. The method according to any one of Aspects 1 to 3, wherein determining the operating point includes determining one or more of compressor speed, discharge pressure, suction pressure, process fluid temperature setpoint, process fluid flow rate, and ambient temperature.

[0104] Aspect 5. The method according to any one of aspects 1 to 4, further comprising:

[0105] The operation point is stored as the previously determined operation point.

[0106] Aspect 6. The method according to any one of Aspects 1 to 5, wherein when the region of the operation diagram is a first region, adjusting the VFD input to the first input includes adjusting the pulse width modulation (PWM) frequency of the VFD.

[0107] Aspect 7. The method according to any one of Aspects 1 to 5, wherein when the region of the operation diagram is a second region, adjusting the VFD input to the first input includes adjusting the pulse width modulation (PWM) mode of the VFD.

[0108] Aspect 8. The method according to any one of Aspects 1 to 5, wherein adjusting the VFD input to the first input when the region of the operation diagram is a third region includes adjusting the motor cooling.

[0109] Aspect 9. The method according to any one of Aspects 1 to 8, wherein the operating constraint is one or more of shaft elongation constraint, motor temperature constraint and driver temperature constraint.

[0110] Aspect 10. A heating, ventilation, air conditioning and cooling (HVACR) system having a variable frequency drive (VFD), the system comprising:

[0111] Compressors, condensers, expanders, and evaporators connected in a fluid manner; and

[0112] Controller

[0113] The controller is configured as follows:

[0114] Determine the first compression efficiency;

[0115] Determine the operation point;

[0116] When the difference between the operation point and the previously determined operation point exceeds a predetermined threshold, the area of ​​the operation diagram is determined;

[0117] Based on the region of the operation diagram, the VFD input is adjusted to the first input;

[0118] The first input is used to control the VFD to continue for a predetermined period of time;

[0119] Determine the second compression efficiency and operational constraints;

[0120] The VFD input is adjusted to the second input based on the difference between the first compression efficiency and the second compression efficiency and the operational constraints; and

[0121] The VFD is controlled using the second input.

[0122] Aspect 11. The HVACR system according to aspect 10, wherein the controller is further configured to: determine a first kW / Ton as the first compression efficiency, and determine a second kW / Ton as the second compression efficiency.

[0123] Aspect 12. The HVACR system according to aspect 10, wherein the controller is further configured to: determine a first energy performance level as the first compression efficiency, and determine a second energy performance level as the second compression efficiency.

[0124] Aspect 13. The HVACR system according to any one of Aspects 10 to 12, wherein the controller is further configured to determine one or more of compressor speed, discharge pressure, suction pressure, process fluid temperature setpoint, process fluid flow rate and ambient temperature as the operating point.

[0125] Aspect 14. The HVACR system according to any one of Aspects 10 to 13, wherein the controller is further configured to store the operating point as the previously determined operating point.

[0126] Aspect 15. The HVACR system according to any one of Aspects 10 to 14, wherein when the region of the operation diagram is a first region, the controller is further configured to adjust the pulse width modulation (PWM) frequency of the VFD.

[0127] Aspect 16. The HVACR system according to any one of Aspects 10 to 14, wherein when the region of the operation diagram is a second region, the controller is further configured to adjust the pulse width modulation (PWM) mode of the VFD.

[0128] Aspect 17. The HVACR system according to any one of Aspects 10 to 14, wherein when the region of the operation diagram is a third region, the controller is further configured to adjust motor cooling.

[0129] Aspect 18. The HVACR system according to any one of Aspects 10 to 17, wherein the operating constraint is one or more of shaft elongation constraint, motor temperature constraint and drive temperature constraint.

[0130] Aspect 19. The HVACR system according to any one of Aspects 10 to 18, wherein the compressor is driven by a VFD-driven motor.

[0131] Aspect 20. A method for adjusting the compression efficiency of a heating, ventilation, air conditioning, and refrigeration (HVACR) system having a variable frequency drive (VFD), the method comprising:

[0132] The first compression efficiency is determined by the controller;

[0133] The operating point is determined by the controller;

[0134] Machine learning control is applied to adjust the VFD input when the difference between the operating point and a previously determined operating point exceeds a predetermined threshold;

[0135] Determine operational constraints;

[0136] The VFD input is applied based on the operational constraints; and

[0137] The VFD is controlled using the VFD input.

[0138] The terminology used in this specification is intended to describe particular embodiments and is not intended to be limiting. Unless otherwise expressly stated, the terms “a,” “an,” “the,” and “the” also include the plural forms. When used in this specification, the terms “comprising” and / or “including” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or components.

[0139] Regarding the foregoing description, it should be understood that changes in details may be made without departing from the scope of this disclosure, particularly in terms of the structural materials used and the shape, size, and arrangement of components. This specification and the described embodiments are merely exemplary, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A method for adjusting the compression efficiency of a heating, ventilation, air conditioning, and refrigeration (HVACR) system having a variable frequency drive (VFD), the method comprising: The first compression efficiency is determined by the controller; The operating point is determined by the controller; When the difference between the operating point and the previously determined operating point does not exceed a predetermined threshold, the region of the compressor's operating diagram is determined; Based on the area determined by the operation diagram, the VFD input is adjusted to the first input; The VFD is controlled using the first input during a predetermined time period; Determine the second compression efficiency and operational constraints; Based on the difference between the first compression efficiency and the second compression efficiency and the operational constraints, the VFD input is adjusted to the second input; and The VFD is controlled using the second input.

2. The method according to claim 1, wherein, Determining the first compression efficiency includes determining the first kW / Ton. Determining the second compression efficiency includes determining the second kW / Ton.

3. The method according to claim 1, wherein, Determining the first compression efficiency includes determining the first energy performance level. Determining the second compression efficiency includes determining the second energy performance level.

4. The method according to claim 1, wherein, Determining the operating point includes determining one or more of the following: compressor speed, discharge pressure, suction pressure, process fluid temperature setpoint, process fluid flow rate, and ambient temperature.

5. The method according to claim 1, further comprising: When the difference between the operation point and the previously determined operation point does not exceed a predetermined threshold, the operation point is stored as the previously determined operation point.

6. The method according to claim 1, wherein, When the defined region of the operation diagram is a first region, adjusting the VFD input to the first input includes adjusting the pulse width modulation (PWM) frequency of the VFD.

7. The method according to claim 1, wherein, When the determined region of the operation diagram is the second region, adjusting the VFD input to the first input includes adjusting the pulse width modulation (PWM) mode of the VFD.

8. The method according to claim 1, wherein, When the region determined by the operation diagram is the third region, adjusting the VFD input to the first input includes adjusting the motor cooling.

9. The method according to claim 1, wherein, The operational constraints are one or more of the following: shaft elongation constraints, motor temperature constraints, and driver temperature constraints.

10. A heating, ventilation, air conditioning, and cooling (HVACR) system with a variable frequency drive (VFD), the system comprising: The compressor, condenser, expander, and evaporator are fluidly connected; and Controller The controller is configured as follows: Determine the first compression efficiency; Determine the operation point; When the difference between the operating point and the previously determined operating point does not exceed a predetermined threshold, the region of the compressor's operating diagram is determined; Based on the area determined by the operation diagram, the VFD input is adjusted to the first input; The VFD is controlled using the first input during a predetermined time period; Determine the second compression efficiency and operational constraints; Based on the difference between the first compression efficiency and the second compression efficiency, and the operational constraints, the VFD input is adjusted to the second input; and The VFD is controlled using the second input.

11. The HVACR system according to claim 10, wherein, The controller is also configured to: determine a first kW / Ton as the first compression efficiency, and determine a second kW / Ton as the second compression efficiency.

12. The HVACR system according to claim 10, wherein, The controller is further configured to: determine a first energy performance level as the first compression efficiency, and determine a second energy performance level as the second compression efficiency.

13. The HVACR system according to claim 10, wherein, The controller is also configured to determine one or more of the following as the operating point: compressor speed, discharge pressure, suction pressure, process fluid temperature setpoint, process fluid flow rate, and ambient temperature.

14. The HVACR system according to claim 10, wherein, The controller is also configured to store the operation point as the previously determined operation point when the difference between the operation point and the previously determined operation point does not exceed a predetermined threshold.

15. The HVACR system according to claim 10, wherein, When the defined region of the operation diagram is the first region, the controller is also configured to adjust the pulse width modulation (PWM) frequency of the VFD.

16. The HVACR system according to claim 10, wherein, When the region determined by the operation diagram is the second region, the controller is also configured to adjust the pulse width modulation (PWM) mode of the VFD.

17. The HVACR system according to claim 10, wherein, When the region determined by the operation diagram is the third region, the controller is also configured to adjust the motor cooling.

18. The HVACR system according to claim 10, wherein, The operational constraints are one or more of the following: shaft elongation constraints, motor temperature constraints, and driver temperature constraints.

19. The HVACR system according to claim 10, wherein, The compressor is a variable speed compressor driven by a VFD-driven motor.

20. A method for adjusting the compression efficiency of a heating, ventilation, air conditioning, and refrigeration (HVACR) system having a variable frequency drive (VFD), the method comprising: The first compression efficiency is determined by the controller; The operating point is determined by the controller; When the difference between the operation point and the previously determined operation point does not exceed a predetermined threshold, machine learning control is applied to adjust the VFD input; Determine operational constraints; The VFD input is applied based on the operational constraints; and The VFD is controlled using the VFD input.

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