阅读说明：本技术 使用电机温度超控的容量控制技术 (Capacity control techniques using motor temperature override ) 是由 柯提斯·克里斯蒂安·克莱恩 于 2018-12-28 设计创作，主要内容包括：一种控制系统(122)包括处理电路系统和存储器电路系统,所述存储器电路系统存储有用于冷却器系统(14)的基于温度的容量控制方案(200),并且所述处理电路系统被配置用于执行所述基于温度的容量控制方案(200)。根据以下各项来执行所述基于温度的容量控制方案(200)：所监测到的被配置用于驱动所述冷却器系统(14)的压缩机(32)的电机(50)的温度、与所述监测到的温度相对应的第一温度阈值、以及与所述监测到的温度相对应的高于所述第一温度阈值的第二温度阈值。(A control system (122) includes processing circuitry and memory circuitry, the memory circuitry storing a temperature-based capacity control scheme (200) for a chiller system (14), and the processing circuitry configured to execute the temperature-based capacity control scheme (200). Performing the temperature-based capacity control scheme (200) according to: a monitored temperature of a motor (50) configured to drive a compressor (32) of the chiller system (14), a first temperature threshold corresponding to the monitored temperature, and a second temperature threshold corresponding to the monitored temperature that is higher than the first temperature threshold.)

1. A chiller system comprising:

a compressor of a refrigeration circuit having the compressor, a condenser, and an evaporator in fluid communication;

a motor configured to drive the compressor, wherein the motor is fluidly coupled to the condenser to allow the motor to receive refrigerant from the condenser for cooling the motor;

a motor cooling valve fluidly positioned between the motor and the condenser, wherein the motor cooling valve is continuously electronically adjustable between a fully open position and a fully closed position to adjust an amount of refrigerant introduced into the motor between a full refrigerant flow and no refrigerant flow, respectively; and

a capacity control system configured to control loading or unloading of the chiller system according to a motor temperature-based capacity control scheme executed in response to determining that the motor cooling valve is in the fully open position, wherein the motor temperature-based capacity control scheme is executed according to: a monitored temperature associated with the motor, a first temperature threshold corresponding to the monitored temperature, and a second temperature threshold corresponding to the monitored temperature that is higher than the first temperature threshold.

2. The system of claim 1, wherein the temperature-based capacity control scheme comprises a loading limit zone corresponding to a temperature range between the first temperature threshold and the second temperature threshold, wherein the loading limit zone is configured to proportionally limit loading of the chiller system based on an amount by which the monitored temperature has exceeded the first threshold.

3. The chiller system of claim 1 wherein the temperature-based capacity control scheme comprises a no load command override associated with the second temperature threshold, wherein the no load command override does not allow a load command to be provided to a component configured to allow loading of the compressor.

4. The chiller system of claim 1, wherein the temperature-based capacity control scheme comprises an override zone associated with a temperature range above the second threshold and below a chiller shutdown temperature, wherein the override zone is configured to proportionately unload the chiller system based on the amount by which the monitored temperature has exceeded the second temperature threshold.

5. The chiller system of claim 4 wherein a capacity control unload level is used if the capacity control requires that the unload level of the override zone be higher than its proportional unload level.

6. The chiller system of claim 1, wherein the electric machine comprises a housing, a rotor positioned within a stator having stator windings, an Electromagnetic (EM) bearing configured to support the rotor, and a Magnetic Bearing Controller (MBC) configured to regulate operation of the EM bearing, the MBC having a heat sink, and wherein the monitored temperature is a stator winding temperature, an EM bearing temperature, or an MBC temperature.

7. The chiller system of claim 1 wherein the electric machine comprises a housing, a rotor positioned within a stator having stator windings, and a lubricated bearing configured to support the rotor, and wherein the monitored temperature is a temperature of the bearing itself or a temperature of lubricant on the bearing.

8. The chiller system of claim 7 wherein the lubricated bearing comprises a refrigerant lubricated bearing.

9. A method of performing capacity control in a chiller system, the method comprising:

driving a compressor of the chiller system using a motor;

cooling the motor using a refrigerant supplied from a refrigeration circuit of the chiller system, the refrigeration circuit having the compressor, condenser and evaporator in fluid communication;

controlling an amount of refrigerant provided to the motor for cooling using a motor cooling valve fluidly positioned between the motor and the condenser, wherein the motor cooling valve is continuously electronically adjustable between a fully open position and a fully closed position to adjust an amount of refrigerant introduced into the motor between full refrigerant flow and no refrigerant flow, respectively; and

controlling loading or unloading of the chiller system using a capacity control system according to a motor temperature-based capacity control scheme executed in response to determining that the motor cooling valve is in the fully open position, wherein the motor temperature-based capacity control scheme is executed according to: a monitored temperature associated with the motor, a first temperature threshold corresponding to the monitored temperature, and a second temperature threshold corresponding to the monitored temperature that is higher than the first temperature threshold.

10. The method of claim 9, comprising: in response to determining that the monitored temperature is within a temperature range between the first temperature threshold and the second temperature threshold, proportionally limiting loading of the chiller system based on an amount by which the monitored temperature has exceeded the first threshold.

11. The method of claim 9, comprising: in response to determining that the monitored temperature has reached the second temperature threshold, disabling provision of a load command to a component configured for loading the chiller system.

12. The chiller system of claim 9 comprising: in response to determining that the monitored temperature is within a temperature range between the second temperature threshold and a chiller shutdown temperature, proportionally unloading the chiller system based on an amount by which the monitored temperature has exceeded the second threshold.

13. The method of claim 9, wherein the electric machine comprises a housing, a rotor positioned within a stator having stator windings, an Electromagnetic (EM) bearing configured to support the rotor, and a Magnetic Bearing Controller (MBC) configured to regulate operation of the EM bearing, the MBC having a heat sink, and wherein the monitored temperature is a stator winding temperature, an EM bearing temperature, or an MBC temperature.

14. The method of claim 9, wherein the electric machine comprises a housing, a rotor positioned within a stator having stator windings, and a lubricated bearing configured to support the rotor, and wherein the monitored temperature is a temperature of the bearing itself or a temperature of lubricant on the bearing.

15. The method of claim 14, wherein the lubricated bearing comprises a refrigerant lubricated bearing, and wherein the monitored temperature is a temperature of a refrigerant used to lubricate the bearing.

16. A control system having processing circuitry and memory circuitry, the memory circuitry storing a temperature-based capacity control scheme for a chiller system, and the processing circuitry configured to execute the temperature-based capacity control scheme, wherein the motor temperature-based capacity control scheme is executed in accordance with: a monitored temperature of a motor configured to drive a compressor of the chiller system, a first temperature threshold corresponding to the monitored temperature, and a second temperature threshold corresponding to the monitored temperature that is higher than the first temperature threshold.

17. The control system of claim 16, wherein the temperature-based capacity control scheme is executed in response to determining that a maximum allowable refrigerant flow from a condenser of the chiller system is being provided to the electric machine.

18. The control system of claim 17, wherein the temperature-based capacity control scheme is executed in response to determining that a motor cooling valve controlling the flow of refrigerant to the motor is in a fully open position.

19. The control system of claim 16, wherein the temperature-based capacity control scheme includes a loading limit zone corresponding to a temperature range between the first temperature threshold and the second temperature threshold, wherein the loading limit zone is configured to proportionally limit loading of the chiller system based on an amount by which the monitored temperature has exceeded the first threshold.

20. The control system of claim 19, wherein the temperature-based capacity control scheme comprises:

a no load command override associated with the second temperature threshold, wherein the no load command override does not allow a load command to be provided to a component configured to allow loading of the chiller system; and

an override zone associated with a temperature range above the second threshold and below a cooler shutdown temperature, wherein the override zone is configured to proportionally unload the cooler system based on an amount by which the monitored temperature has exceeded the second temperature threshold.

Background

The present application relates generally to vapor compression systems, such as chillers, and more particularly relates to a compressor of a chiller.

This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present disclosure, which are described in detail 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.

Vapor compression systems (e.g., chillers) utilize a working fluid, commonly referred to as a refrigerant, that changes phase between vapor, liquid, and combinations thereof in response to being subjected to different temperatures and pressures associated with operation of the vapor compression system. For example, a heating, ventilation, air conditioning and refrigeration (HVAC & R) system may include a chiller, which is a type of vapor compression system that circulates a refrigerant to remove heat from or cool a flow of water that passes through tubes extending through an evaporator of the chiller. The flow of cooling water may be directed to nearby structures to absorb heat or provide cooling, and then circulated back to the chiller evaporator for re-cooling.

Chiller systems utilize a compressor (such as a centrifugal compressor) to compress a refrigerant as part of a refrigeration cycle and force the refrigerant through the chiller system. The capacity of the compressor (which generally refers to the amount of refrigerant or fluid operated by the compressor) generally determines the overall capacity of the chiller system (e.g., the capacity of the chiller system to generate cooled fluid). In this manner, an increase in fluid flow into the compressor increases the capacity of the chiller system, while a decrease in fluid flow into the compressor decreases the capacity of the chiller system.

Such a compressor includes a motor that rotates a shaft to operate the compressor. Operation of the motor generates heat within the motor, which if left uncontrolled, may degrade the performance of the motor over time. Indeed, in some cases, once the motor reaches a certain temperature, the control system of the chiller may indicate a fault condition, which shuts down the chiller to allow the motor to return to an acceptable operating temperature.

Centrifugal compressors may encounter instabilities, such as surge or stall, during operation. Surge or surging is a transient phenomenon in which there is an oscillation in pressure or flow and may cause the flow to flow completely back through the compressor. Surging, if left uncontrolled, can cause excessive vibration in both rotating and stationary components of the compressor and can result in permanent damage to the compressor. One technique to correct a surge condition may involve opening a hot gas bypass valve to return a portion of the discharge gas of the compressor to the compressor inlet, thereby increasing the flow at the compressor inlet. In contrast, stall or rotating stall is a local flow separation in one or more components of the compressor and may have discharge pressure disturbances at a fundamental frequency that is less than the rotational frequency of the impeller of the compressor. Rotating stall in a fixed speed centrifugal compressor is primarily located in the compressor's diffuser and can be remedied using a Variable Geometry Diffuser (VGD). The presence of rotating stall in the compressor may be a precursor to an impending surge condition.

In many control systems, capacity control, surge/stall control, and motor temperature control may conflict with one another. For example, capacity control may dictate compressor operating conditions that may cause surge or stall conditions to occur, and/or may raise the motor temperature beyond an acceptable operating temperature. Similarly, surge/stall control and motor temperature control may not provide the desired output capacity for capacity control.

Disclosure of Invention

The following outlines certain embodiments commensurate with the scope of the initially claimed subject matter. These embodiments are not intended to limit the scope of the present disclosure, but rather these embodiments are intended to provide only a brief summary of certain disclosed embodiments. Indeed, the disclosure may encompass a variety of forms that may be similar to or different from the embodiments set forth below.

Drawings

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

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

FIG. 2 is a perspective view of an embodiment of a vapor compression system according to one aspect of the present disclosure;

FIG. 3 is a schematic view of an embodiment of the vapor compression system of FIG. 2, according to an aspect of the present disclosure;

FIG. 4 is a schematic view of another embodiment of the vapor compression system of FIG. 2, in accordance with an aspect of the present disclosure;

fig. 5 is a schematic diagram of an embodiment of a cooling system configured for cooling a compressor motor of the vapor compression system of fig. 1-4, according to an aspect of the present disclosure;

FIG. 6 is a schematic diagram of an embodiment of the compressor motor of FIGS. 1-5 having a plurality of temperature sensors providing temperature feedback to a motor temperature control system in accordance with an aspect of the present disclosure;

FIG. 7 is an elevation view of an embodiment of the vapor compression system of FIG. 1, according to an aspect of the present disclosure;

FIG. 8 is a cross-sectional view of the embodiment of the compressor of FIGS. 2-4 and 7 in accordance with an aspect of the present disclosure;

FIG. 9 is a process flow diagram illustrating an embodiment of a capacity control process including limits and overrides in accordance with an aspect of the present disclosure; and

fig. 10 is a graphical illustration of a motor temperature based capacity control scheme having a load limit zone and an override zone, executed in accordance with a monitored motor temperature in accordance with an aspect of the present disclosure.

Embodiments include a chiller system having a compressor of a refrigeration circuit having the compressor, a condenser, and an evaporator in fluid communication. The chiller system also includes a motor configured to drive the compressor. The electric motor is fluidly coupled to the condenser to allow the electric motor to receive refrigerant from the condenser for cooling the electric motor. A motor cooling valve is fluidly positioned between the motor and the condenser, and the motor cooling valve is continuously electronically adjustable between a fully open position and a fully closed position to regulate an amount of refrigerant introduced into the motor between full refrigerant flow and no refrigerant flow, respectively. The chiller system also includes a capacity control system configured to control loading or unloading of the chiller system according to a motor temperature-based capacity control scheme executed in response to determining that the motor cooling valve is in the fully open position. Executing the motor temperature-based capacity control scheme according to: a monitored temperature associated with the motor, a first temperature threshold corresponding to the monitored temperature, and a second temperature threshold corresponding to the monitored temperature that is higher than the first temperature threshold.

Another embodiment includes a method of performing capacity control in a chiller system. The method comprises the following steps: driving a compressor of the chiller system using a motor; cooling the motor using a refrigerant supplied from a refrigeration circuit of the chiller system, the refrigeration circuit having the compressor, condenser and evaporator in fluid communication; controlling an amount of refrigerant provided to the motor for cooling using a motor cooling valve fluidly positioned between the motor and the condenser, wherein the motor cooling valve is continuously electronically adjustable between a fully open position and a fully closed position to adjust an amount of refrigerant introduced into the motor between full refrigerant flow and no refrigerant flow, respectively; and controlling loading or unloading of the chiller system using a capacity control system according to a motor temperature-based capacity control scheme executed in response to determining that the motor cooling valve is in the fully open position, wherein the motor temperature-based capacity control scheme is executed according to: a monitored temperature associated with the motor, a first temperature threshold corresponding to the monitored temperature, and a second temperature threshold corresponding to the monitored temperature that is higher than the first temperature threshold.

Another embodiment includes a control system comprising processing circuitry and memory circuitry, the memory circuitry storing a temperature-based capacity control scheme for a chiller system, and the processing circuitry configured to execute the temperature-based capacity control scheme. Executing the motor temperature-based capacity control scheme according to: a monitored temperature of a motor configured to drive a compressor of the chiller system, a first temperature threshold corresponding to the monitored temperature, and a second temperature threshold corresponding to the monitored temperature that is higher than the first temperature threshold.