Takeoff speed detection

Abstract

A compressor includes a rotating shaft supported by a plurality of air foil bearings, a frequency sensor for detecting the frequency of a signal emitted by the device during rotation of the rotating shaft, a controller for detecting a takeoff speed of the plurality of air foil bearings in response to the frequency of the signal, and a memory for storing the takeoff speed, wherein the memory is communicatively connected to the device controller for controlling the rotation speed of the rotating shaft in response to the takeoff speed, wherein the detection of the takeoff speed is in response to a sudden change in the frequency of the signal emitted by the device during the coasting deceleration of the compressor from maximum rotation speed to zero rotation speed.

Description

Technical Field

[0001] This disclosure generally relates to a test system for determining the takeoff speed or takeoff rotational speed of a compressor with foil bearings, and more specifically, to determining the takeoff speed of an air foil bearing in response to the frequency and amplitude of vibrations of the compressor and the rotational speed measured at multiple times during the transition between maximum and zero rotational speeds. Background Technology

[0002] Foil bearings, also known as air foil bearings (AFB), are a type of bearing that uses a spring-loaded foil journal liner to support a rotating shaft. The foil is separated from the shaft by a thin layer of air or liquid. The pressure from this thin layer of air or liquid keeps the moving surface separate from the stationary surface, allowing for low-friction, high-speed rotation. Foil bearings, such as AFB, are commonly used in turbomachinery applications, such as gas turbines, compressors, and blowers. Air foil bearings can operate at very high speeds, making them ideal for turbomachinery applications. AFB also features very low friction, which can result in significant energy savings.

[0003] Air gaps (AFBs) are self-starting, meaning they do not require an external pressurization system for the working fluid. AFBs use compliant, spring-loaded foil journal liners to support the shaft. Once the shaft rotates fast enough, the AFB reaches takeoff speed (LOS), at which point the air pushes the foils away from the shaft, preventing contact. The shaft and foils are separated by high-pressure air, generated by the rotation drawing gas into the bearing via a viscous effect. This high shaft speed relative to the foils is necessary to initiate the air gap, and once this condition is achieved, wear does not occur. Below takeoff speed, the bearing will operate under boundary lubrication or mixed lubrication conditions, which can lead to increased friction and wear. AFBs require quality testing prior to shipment to determine the LOS of each AFB to ensure proper bearing operation, that the AFB meets design and performance specifications, and for regulatory compliance purposes.

[0004] There are several methods for determining the takeoff speed of an air foil bearing. One common method is to measure how the bearing's frictional torque changes as speed increases or decreases. Takeoff speed is typically defined as the speed at which the frictional torque begins to decrease, or it can be defined using computational fluid dynamics (CFD) modeling. CFD modeling can be used to simulate airflow through the bearing and predict takeoff speed. These LOS tests can be time-consuming and difficult to implement in a production environment. It is desirable to incorporate a test that can detect bearing quality problems before shipping complete products containing AFBs, such as compressors, fuel cell compressors, or air conditioning compressors, from the production assembly line. Other desirable features and characteristics of this disclosure will become apparent from the following detailed description and the appended claims, in conjunction with the accompanying drawings and the discussion in this background.

[0005] The information disclosed in this background section is only intended to enhance the understanding of the background of this invention, and therefore may contain information that does not constitute prior art known to those skilled in the art in this country. Summary of the Invention

[0006] In one embodiment, a system for determining the takeoff speed of an AFB (Air Foil Bearing) incorporated into a compressor includes: a device having a rotating shaft supported by a plurality of air foil bearings; a sensor for detecting the frequency and amplitude of a signal emitted by the device during rotation of the rotating shaft; a controller for detecting the takeoff speed of the plurality of air foil bearings in response to the frequency and amplitude of the signal; and a memory for storing the takeoff speed, wherein the memory is communicatively coupled to the device controller for controlling the rotation speed of the rotating shaft in response to the takeoff speed.

[0007] In another embodiment, a method for determining the takeoff speed of an air foil bearing incorporated in a compressor includes: controlling a device having a rotating shaft supported by a plurality of air foil bearings to rotate at a predetermined operating rotational speed; disconnecting a drive source coupled to the rotating shaft, causing the rotating shaft to begin a coasting deceleration (or idle deceleration) phase from a maximum operating rotational speed to zero rotational speed; detecting the frequency of vibrations of the device and the rotational speed of the rotating shaft by a frequency sensor at multiple times during the coasting deceleration phase; determining the takeoff speed of the air foil bearing by a test controller in response to the plurality of frequencies; and storing the takeoff speed in a memory communicatively coupled to the device.

[0008] Furthermore, a compressor testing system includes: a controller for determining the rotational speed of a compressor shaft supported by an air foil bearing; a sensor, such as an accelerometer or inertial measurement unit, for measuring the frequency of vibrations generated in response to the rotation of the compressor shaft; a controller for determining the takeoff speed of the air foil bearing in response to the frequency of the vibrations and the rotational speed measured at multiple times during a rotational speed transition between zero rotational speed and a predetermined rotational speed; and a compressor controller for controlling the operation of the compressor such that the operating rotational speed of the compressor shaft is greater than the takeoff speed.

[0009] The advantages and other advantages and features of this disclosure will become apparent from the following detailed description of preferred embodiments when read in conjunction with the accompanying drawings. Attached Figure Description

[0010] This disclosure will be described below in conjunction with the following drawings, wherein like reference numerals denote like elements, and in the drawings: Figure 1 An exemplary compressor construction according to an exemplary embodiment of the present disclosure is shown; Figure 2 An exemplary system for adjusting the rotational speed of a compressor is shown according to an exemplary embodiment of the present disclosure; Figure 3 An exemplary method for adjusting the rotational speed of a compressor is shown according to an exemplary embodiment of the present disclosure; Figure 4 Another exemplary system for regulating the rotational speed of a compressor, according to an exemplary embodiment of the present disclosure, is shown; and Figure 5 Another exemplary method for adjusting the rotational speed of a compressor is shown in accordance with an exemplary embodiment of the present disclosure. Detailed Implementation

[0011] The following specific embodiments are merely exemplary in nature and are not intended to limit the scope of this disclosure or its application and use. Furthermore, they are not intended to be construed as being bound by any theories presented in the foregoing background or the following specific embodiments.

[0012] Figure 1 This is a schematic diagram of an example turbomachinery, such as compressor 100, which is incorporated within engine system 101 and includes one or more features of this disclosure. It should be understood that in additional embodiments of this disclosure, compressor 100 may be another turbomachinery (e.g., a turbocharger, a turbo-free compressor device, etc.). Furthermore, the turbomachinery of this disclosure may be incorporated into multiple systems other than the engine system without departing from the scope of this disclosure. For example, the turbomachinery of this disclosure may be incorporated into a fuel cell system for compressing air supplied to a fuel cell stack, or the turbomachinery may be incorporated into another system without departing from the scope of this disclosure.

[0013] Generally, the compressor 100 may include a housing 103 and a rotating assembly 102 supported within the housing 103 by a bearing system 105 for rotation about an axis 104. The bearing system 105 may be of any suitable type, such as a roller bearing or an air bearing system. As shown in the illustrated embodiment, the housing 103 may include a turbine housing 106, a compressor housing 107, and an intermediate housing 109. The intermediate housing 109 may be axially disposed between the turbine housing 106 and the compressor housing 107.

[0014] Furthermore, the rotating assembly 102 may include a turbine impeller 111, a compressor impeller 113, and a shaft 115. The turbine impeller 111 is substantially located within a turbine housing 106. The compressor impeller 113 is substantially located within a compressor housing 107. The shaft 115 extends along the axis of rotation 104 through an intermediate housing 109 to connect the turbine impeller 111 to the compressor impeller 113. Thus, the turbine impeller 111 and the compressor impeller 113 can rotate together as a whole about the axis 104.

[0015] The turbine housing 106 and turbine impeller 111 cooperate to form a turbine stage (i.e., turbine section) configured to circumferentially receive a high-pressure, high-temperature exhaust flow 121 from the exhaust manifold 123 of the engine, particularly from the internal combustion engine 125. The turbine impeller 111 and other components of the rotating assembly 102 therefrom are driven to rotate about an axis 104 by the high-pressure, high-temperature exhaust flow 121, which becomes a low-pressure, low-temperature exhaust flow 127 released into the downstream exhaust pipe 126.

[0016] The compressor housing 107 and the compressor impeller 113 form a compressor stage (i.e., a compressor section). The compressor impeller 113 is driven to rotate by an exhaust-driven turbine impeller 111, which is configured to compress received input air 131 (e.g., ambient air, or pressurized air from a previous stage in a multi-stage compressor) into a circumferentially expelled pressurized airflow 133 from the compressor housing 107. The compressor housing 107 may have a shape (e.g., a volute shape or other shape) configured to guide and pressurize the air blown out from the compressor impeller 113. Due to the compression process, the pressurized airflow is characterized by a temperature higher than that of the input air 131.

[0017] The pressurized airflow 133 can be directed through an air cooler 135 (i.e., an intercooler), such as a convection-cooled booster air cooler. The air cooler 135 can be configured to dissipate heat from the pressurized airflow 133, thereby increasing its density. The resulting cooled and pressurized output airflow 137 is directed into the intake manifold 139 of the internal combustion engine 125, or alternatively, into a subsequent tandem compressor stage.

[0018] Additionally, the compressor 100 may include a motor stage 112. The motor stage 112 may be defined by an intermediate housing 109 and a motor 114 housed therein. A shaft 115 may extend through the motor stage 112, and the motor 114 may be operatively coupled to the shaft. The motor 114 may be an electric motor, a generator, or a combination of both. Therefore, the motor 114 may be configured as a motor to convert electrical energy into mechanical (rotational) energy of the shaft 115 to drive the rotating assembly 102. Alternatively, the motor 114 may be configured as a generator to convert the mechanical energy of the shaft 115 into electrical energy stored in a battery or the like. As described above, the motor 114 may be configured as a motor / generator combination, and in some embodiments, the motor 114 may also be configured to switch between motor mode and generator mode.

[0019] For the purposes of discussion, motor 114 will be referred to as motor 116. Motor 116 may include a rotor component (e.g., a plurality of permanent magnets) supported on shaft 115 to rotate with rotating assembly 102. Motor 116 may also include a stator component (e.g., a plurality of windings, etc.) housed and supported within intermediate housing 109. In some embodiments, motor 116 may be axially disposed between a first bearing 141 and a second bearing 142 of bearing system 105. Furthermore, motor 116 may be housed by motor housing 118 of intermediate housing 109. Motor housing 118 may be a thin-walled or shell-like housing that encloses the stator component of motor 116. Motor housing 118 may also surround axis 104, and shaft 115 may extend through it.

[0020] Additionally, compressor 100 may include an integrated controller 150. The integrated controller 150 typically includes a controller housing 152 and numerous internal components 154 (e.g., circuitry, electronics, cooling components, support structures, etc.) housed within the controller housing 152. The integrated controller 150 can control various functions. For example, the integrated controller 150 can control motor 116, thereby controlling certain parameters of the rotation assembly 102 (torque, angular velocity, start / stop, acceleration, etc.). In some embodiments, the integrated controller 150 may also communicate with a battery, an electrical control unit (ECU), or other components of the corresponding vehicle. More specifically, the integrated controller 150 may receive DC power from the vehicle battery and convert that power into AC power to control motor 116. In an additional embodiment where motor 114 is a motor / generator combination, the integrated controller 150 can operate to switch motor 114 between motor and generator functions.

[0021] In some embodiments, the integrated controller 150 may be axially disposed between the compressor stage and the turbine stage of the compressor 100 relative to axis 104. Therefore, as shown, the integrated controller 150 may be disposed close to the motor 116 and may be integrated close to the motor 116. For example, as shown in the illustrated embodiment, the integrated controller 150 may be disposed on the motor housing 118 and may be arranged radially above the motor housing 118. More specifically, the integrated controller 150 may extend and wrap around axis 104 to cover the motor 116, such that the motor 116 is radially disposed between axis 115 and the integrated controller 150. The integrated controller 150 may also extend circumferentially about axis 104 and may cover, overlap, and wrap around at least a portion of the motor housing 118. In some embodiments, the integrated controller 150 may be wound around axis 104 at an angle between approximately forty-five degrees (45°) and three hundred and sixty-five degrees (365°).

[0022] As shown, housing 152 may be generally arcuate to extend about axis 104 and generally conform to the circular profile of compressor 100. Housing 152 may also be a hollow outer shell member enclosing internal components 154. An electrical connector may extend through housing 152 for electrical connection to internal components 154. Additionally, openings may be present for fluid couplings (e.g., couplings for fluid coolant). Furthermore, controller housing 152 may define a portion of the exterior of compressor 100. Outer surface 153 of controller housing 152 may extend about axis 104 and may be radially opposed to axis 104. Outer surface 153 may be at least partially smoothed about axis 104 as shown, or outer surface 153 may include one or more plates (e.g., a series of such plates arranged tangentially relative to axis 104). Outer surface 153 may be positioned at approximately the same radius as adjacent compressor housing 107 and / or turbine housing 106. Therefore, the overall size and profile of compressor 100 including controller 150 can be very compact.

[0023] Internal components 154 can be housed within the controller housing 152. Furthermore, at least some of the internal components 154 can extend in an arc, coil, and / or be arranged around axis 104, as will be discussed below. Additionally, as will be discussed below, the internal components 154 can be stacked adjacently along axis 104, making the controller 150 very compact. Therefore, the integrated controller 150 can be compactly arranged and integrated with other components of the turbine stage, compressor stage, and / or compressor 100. Furthermore, the internal components 154 of the controller 150 can be located adjacent to the motor 116 to provide certain advantages. For example, due to this proximity, noise can be reduced to achieve more efficient control of the motor 116.

[0024] Furthermore, the controller 150 may include numerous components providing robust support and efficient cooling. Therefore, the compressor 100 can operate under extreme conditions caused by elevated temperatures, mechanical loads, electrical loads, etc. In any case, the controller 150 can be tightly integrated into the compressor 100 without compromising performance.

[0025] Now for reference Figure 2 This document illustrates a compressor test system 200 for determining the AFB (Action Fusion Speed) takeoff speed in a compressor, according to an exemplary embodiment of this disclosure. The exemplary system 200 may include an electric motor 210, a motor controller 215, an impeller 220, an impeller housing 225, a compressor housing 230, a shaft 240, an AFB 250, and a sensor 260. The exemplary test system 200 illustrates a test configuration, such as one installed in a production environment, for detecting the LOS (Location of Oscillation) of a bearing installed in a centrifugal compressor by detecting the spectrum of a shaft motion probe and / or changes in the acceleration of the compressor housing 230. A centrifugal compressor is a device that uses an electric motor 210, or in some cases, exhaust gas from an engine, to rotate a shaft 240 to drive an impeller 220. The impeller 220 compresses external air and forces this compressed air to an engine or cooling system.

[0026] An electric motor 210 converts electrical energy to generate a magnetic field within one or more coils, referred to as a rotor, to apply magnetic force to one or more stationary permanent magnets within a stator. This rotational motion is transmitted to a common shaft 240 that connects a turbine impeller to an impeller 220. A motor controller 215 can be used to control the rotational speed of the electric motor 210, and in some exemplary embodiments, an inverter circuit can be used to convert direct current (DC) to alternating current (AC) to supply AC current to the rotor of the electric motor 210. The switching rate of the inverter circuit can be used to control the rotational speed of the electric motor 210.

[0027] Impeller 220 can be a rotating impeller used to increase gas pressure. Impeller 220 radially accelerates the gas, which increases its kinetic energy. Then, as the gas passes through a diffuser, the kinetic energy is converted into pressure. Impeller 220 has a series of blades designed to compress the gas from the intake manifold as it flows through the impeller. The compressed gas is then forced into the exhaust manifold, where it can be connected to other vehicle systems for cooling electric vehicle batteries or other vehicle mechanical or electrical systems. Impeller 220 is enclosed within impeller housing 225, which contains the impeller wheel and diffuser, which facilitate further compression of the air.

[0028] Turbine housing 215 and impeller housing 225 can be integrated into compressor housing 230. Compressor housing 230 encloses shaft 240 and AFB 250. AFB 250 is used to support rotating shaft 240, allowing it to rotate at very high speeds. AFB is a type of fluid bearing that uses lift generated by air foils to support a rotating shaft. AFB typically comprises a rotating inner portion and a stationary housing. The rotating inner portion is typically supported by a series of air foils, which are thin, curved plates arranged around the periphery of the shaft. The housing contains a series of air supply holes that supply pressurized air to the air foils. A thin film of pressurized air is created between the inner housing of AFB 250 and the stationary housing to form an air cushion between shaft 240 and compressor housing 230. Although this embodiment is described using AFB, fluid foil bearings can also be used within the scope of embodiments of this disclosure.

[0029] AFB 250s typically must operate at rotational speeds above their LOS (Lower Scale of Operation) for optimal performance and to reduce wear and premature failure. For AFB 250, LOS is the speed at which the AFB 250 transitions from boundary lubrication to hydrodynamic lubrication. Boundary lubrication is a type of lubrication where there is direct contact between two surfaces, which can lead to friction and wear. Hydrodynamic lubrication is a type of lubrication where a thin film of fluid separates the two surfaces, reducing friction and wear. For AFB 250, LOS is the speed at which the rotating shaft 240 generates sufficient lift to float on the air film. Once LOS is reached, the AFB 250 operates under hydrodynamic lubrication conditions, resulting in very low friction and wear. AFB 250s can operate at speeds below LOS, but bearing life will be shortened if the bearing is operated at speeds where the air film thickness is insufficient to prevent contact between the shaft and housing.

[0030] The Loss of Operation (LOS) of an AFB can vary due to manufacturing differences, operating load, and lubricant viscosity. Determining the LOS of a compressor equipped with an AFB during compressor manufacturing is important to detect bearing quality issues before shipment and to establish a minimum rotational speed to ensure the compressor operates at a speed above the LOS, thereby ensuring optimal performance and reliability. To determine the LOS of an installed set of AFBs 250, a sensor 260 is physically coupled to the compressor housing 230 after compressor assembly. The sensor 260 can be an accelerometer or inertial measurement unit for sensing the acceleration of the compressor housing 230, or a microphone for detecting vibrations of the compressor housing 230.

[0031] During end-of-line testing, sensor 260 can be physically attached to compressor housing 230. Sensor 260 can be physically attached using spring clips, magnets, clamps, etc. Electric motor 210, impeller 220, and shaft 240 can then be accelerated to the system's maximum speed, and then allowed to coast back to zero speed with motor control deactivated. During the coasting deceleration process, sensor 260 can collect spectral data and rotational rate data. The spectral data is then analyzed to identify changes in spectral characteristics associated with the transition to AFB foil contact. The AFB foil contact rotational speed can be compared to the equipment's pass / fail criteria. The LOS can then be estimated as a value greater than the foil contact rotational speed by a predetermined margin. The test procedure can then store the LOS in memory, etc. This LOS can be used as an operating parameter of the equipment when installed in a larger system, or it can be used to characterize the equipment regarding design tolerances, etc.

[0032] Turn now Figure 3 The diagram 300 illustrates an exemplary relationship between the compressor's frequency and rotational speed during a deceleration test process, according to an exemplary embodiment of the present disclosure. The diagram 300 shows multiple rotational speed / frequency relationships 320. While exemplary in nature, these multiple relationships 320 may apply to AFBs of different configurations or to individual AFBs of the same design. Exemplary LOS are indicated by a horizontal line 310.

[0033] In some exemplary embodiments, the AFB foil contact rotational speed can be indicated by a step transition or discontinuity 325 in a detected frequency curve. For example, when the compressor is operating at its maximum speed above the LOS, the compressor may vibrate at a specific frequency and / or generate micro-acceleration at a specific frequency. The compressor is then allowed to coast back to zero speed with motor control disabled. During this decrease in rotational speed, the frequency of the vibration or micro-acceleration will smoothly decrease as the AFB rotational speed increases above the LOS. Once the decrease in AFB rotational speed reaches the AFB foil contact rotational speed, the frequency of the vibration or micro-acceleration may experience a discontinuity 325 when the AFB foil contacts the rotating shaft, such as a step function change in frequency or a change in the slope of the relationship between frequency and rotational speed. This discontinuity 325 in the smooth decrease of AFB rotational speed can then be used to determine the AFB foil contact rotational speed and the LOS of the AFB. This LOS can then be stored in memory for use by the compressor controller, etc., during routine operation, or can be used to determine whether the compressor meets required design criteria, etc.

[0034] Turn now Figure 4This illustration shows an exemplary system 400 for detecting LOS in a compressor equipped with AFB, according to an exemplary embodiment of the present disclosure. The exemplary measurement system 400 may include a compressor 410, a turbine controller 420, a sensor 430, a test controller 450, and a memory 440.

[0035] In some exemplary embodiments, compressor 420 is a device under test (DUT) that is tested during or at the end of the manufacturing process. Compressor 420 is equipped with multiple AFBs. Although compressor 420 is described as a DUT, the exemplary systems and methods can be used for any device under test that uses AFBs, and the LOS can be determined for that device in a similar manner or method.

[0036] Sensor 430 can be coupled to the housing or enclosure of compressor 420 to detect vibrations of the compressor. Sensor 430 can be a microphone, accelerometer, inertial measurement unit, or other sensor for detecting the frequency and / or amplitude (or magnitude) of sound or vibrations emitted from compressor 420. In some exemplary embodiments, sensor 430 may include one or more magnets for physically coupling sensor 430 to compressor 420. Alternatively, sensor 420 may be physically coupled to compressor 420 using clamps, clips, or other constraint fasteners suitable for the manufacturing environment.

[0037] The turbine controller 420 is configured to control the rotational speed of the compressor 410 and other operational configurations of the compressor 410. In the case of a compressor driven by an electric motor, the turbine controller 420 can generate control signals or drive currents to power and / or control the electric motor, thereby controlling the rotational speed of the turbine shaft, impeller, and compressor. In some exemplary embodiments, the turbine controller can control a test motor or other device for rotating the shaft of the compressor 410, causing the compressor, impeller, and shaft to rotate such that the shaft rotates to a maximum operating rotational speed. At this maximum operating rotational speed, the rotational speed of the AFB should exceed the LOS. The turbine controller 420 can also be configured to connect the compressor's LOS value to a memory 440, etc.

[0038] In some exemplary embodiments, the test controller 450 may be a processor, a microcontroller having multiple inputs and outputs, or a programmable test control device. The test controller 450 is configured to detect or estimate the rotational speed of the compressor shaft and connect this rotational speed to at least one of the memory 440 or a memory integrated with the test controller 450. The test controller 450 is configured to execute an end-of-line production test algorithm to ensure that the compressor 410 meets required specifications before being shipped to the customer. A portion of this end-of-line production test algorithm may include detecting the loss of order (LOS) of the compressor's AFB and confirming that the LOS is within the required specifications.

[0039] In some exemplary embodiments, the test controller 450 may send a control signal to the turbine controller 420 to request that the compressor 410 be accelerated to its maximum operating speed. The turbine controller 420 may control the compressor 410 to accelerate to its maximum operating speed. The turbine controller 420 may then transmit confirmation back to the test controller 450 that the compressor 410 has accelerated to its maximum operating speed. This confirmation may include the current rotational speed of the compressor 410 determined by the turbine controller 420. The test controller 450 may then request and receive data from the sensor 430 indicating the frequency of vibration of the compressor 410. Next, the test controller 450 may request the turbine controller 420 to disconnect the motor driving the compressor 410, allowing the compressor 410 to coast and decelerate back to zero rotational speed. During this coasting deceleration period, the test controller 450 may request and receive the rotational speed of the compressor 410 from the turbine controller 420, the rotation sensor, etc. The test controller 450 may also receive frequency data from the sensor 430 at times corresponding to the rotational speed of the compressor 410. This frequency data can be correlated with the rotational speed based on the measurement time and stored in memory 440. Test controller 450 can periodically repeat this process throughout the coasting deceleration period until compressor 410 stops rotating to generate multiple rotational speed / frequency pairs.

[0040] Once the compressor 410 stops rotating and multiple rotational speed / frequency pairs are compiled into a data file and stored in memory 440, the test controller 450 can then examine the compiled rotational speed / frequency pairs to determine at what frequency the compressor 410 reaches the AFB foil contact rotational speed. The AFB foil contact rotational speed can be determined in response to a known frequency of AFB foil contact, or it can be determined in response to discontinuities in the frequency / speed relationship. For example, during the bearing takeoff portion of the coasting deceleration phase, the frequency can decrease smoothly as the rotational speed decreases. Once an AFB foil contact event occurs, the frequency can change abruptly and / or the change in rotational speed and / or frequency can begin to decrease at a faster rate due to increased friction. During the AFB foil contact portion of the coasting deceleration phase, the frequency can again decrease smoothly until the compressor 410 stops rotating.

[0041] In response to the detected AFB foil contact rotation speed, the test controller 450 can then determine the LOS of the compressor 410. This LOS can be determined by adding a margin value, such as 10 revolutions per minute, to the AFB foil contact rotation speed. The LOS can be set to the AFB foil contact rotation speed. During operation of the compressor 410, the vehicle control system or vehicle compressor controller can use this LOS to establish a minimum rotation speed for the compressor 410 to reduce wear and ensure optimal performance. This LOS value can be stored in memory, electronic data storage devices, or in documents associated with the compressor 410 when shipped to the customer. The LOS value can then be input into the turbine controller to control the compressor.

[0042] Turn now Figure 5 This document illustrates an exemplary method 500 for controlling a system for detecting Loss of Service (LOS) in a device equipped with an AFB, according to exemplary embodiments of the present disclosure. In some exemplary embodiments, the device may include high-speed turbomachinery, such as compressors, blowers, turbines and compressors, high-speed electric motors and generators, precision equipment, such as machine tools, gyroscopes and aerospace systems, or medical devices, such as dental drills and surgical robots.

[0043] The method first configures the device to rotate 510° to its maximum rotational speed. The compressor can be rotated to its maximum rotational speed via an integrated electric motor, such as in the case of an electric motor-assisted compressor, or via an external drive device, such as an electric motor or other rotational drive device. Once the device has reached its maximum rotational speed, the AFB should operate at a rotational speed higher than the LOS.

[0044] The method then proceeds to detect the frequency of vibrations emitted by the device in response to rotational operation. This frequency can be detected using a microphone, accelerometer, internal measurement unit, or other vibration detection device physically coupled to the device housing. In some exemplary embodiments, a microphone can be used to detect sound waves emitted from the device, which can then be used to determine the frequency of the sound. In some exemplary embodiments, an antenna can be used to detect electromagnetic signals emitted from the device, and the resulting signal from the antenna can then be used to determine the frequency of the electromagnetic signal.

[0045] In response to the detected frequency, the method then proceeds to store the frequency and corresponding rotational speed in a memory or similar storage medium. This rotational speed can be received from the device or detected using a rotational speed sensor or similar means. After storing the initial frequency and rotational speed corresponding to the maximum rotational speed, the method then proceeds to disconnect the drive motor to initiate a coasting deceleration operation of the device, allowing the device's rotational speed to decrease from the maximum rotational speed to a complete stop or zero rotational speed.

[0046] During the coasting deceleration operation, the method continues to detect 550 the frequency of vibrations emitted by the device and stores this frequency, along with the corresponding rotational speed, along with any previously detected frequencies and speeds, in a data file such as memory. After storing the rotational speed and frequency, the method next determines 570 whether the device's rotational speed has reached zero revolutions per minute. If the device has not yet reached zero revolutions per minute, the method returns to detecting subsequent frequencies.

[0047] If the device has reached zero revolutions per minute (rpm), the method then determines the LOS of the device. The LOS can be determined in response to discontinuities in the frequency / rotational speed profile or changes in the slope of the frequency / rotational speed profile. In some exemplary embodiments, the LOS indicates the rate at which an air foil bearing transitions from boundary lubrication to hydrodynamic lubrication. This transition is characterized by a sharp decrease in friction and an increase in load-carrying capacity. The LOS rotational speed value is then stored in a memory communicatively connected to a device controller, etc. In some exemplary embodiments, a test processor, etc., can continuously monitor the frequency / rotational speed pair and detect the LOS before the device reaches zero rpm. Once the test processor detects the LOS, it can store the LOS value in memory and stop the LOS detection algorithm.

[0048] In some exemplary embodiments, LOS values ​​can be used for classification in a manufacturing environment, such as a manufacturing test environment, and control of the equipment 590 can include rework or remanufacturing. For example, if the LOS is greater than a predetermined limit, the compressor can be flagged for rework or remanufactured using an alternative AFB. A maximum LOS value can be defined, and any equipment with an LOS exceeding this value can be rejected or designated for rework. Alternatively, equipment with different LOS values ​​can be classified for different applications with different operating rotational speeds or different reliability requirements. LOS values ​​can also be used to monitor component quality over time, meaning that LOS values ​​will be recorded and stored for further analysis.

[0049] After the device is installed in an application, such as installing a compressor in a vehicle, the LOS (Lower Scale) rotational speed value can then be used to control the device. For example, LOS can be used as the minimum rotational speed during operation. In the compressor example, an electric motor assist can be used to accelerate the compressor during operation and maintain its rotational speed above LOS to reduce wear and improve efficiency.

[0050] While at least one exemplary embodiment has been presented in the foregoing detailed descriptions, it should be understood that numerous variations exist. It should also be understood that the one or more exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or construction of this disclosure in any way. Rather, the foregoing detailed descriptions will provide those skilled in the art with a convenient roadmap for implementing exemplary embodiments of this disclosure. It should be understood that various changes can be made to the function and arrangement of the elements described in the exemplary embodiments without departing from the scope of this disclosure as set forth in the appended claims.

Claims

1. An apparatus comprising: A device having a rotating shaft supported by multiple air foil bearings; A sensor for detecting the amplitude and frequency of a signal emitted by the device during rotation of the rotating shaft; A controller for detecting the takeoff speed of the plurality of air foil bearings in response to the frequency of the signal; as well as A memory for storing the takeoff speed, wherein the memory is communicatively connected to a device controller for controlling the rotation speed of the rotating shaft in response to the takeoff speed.

2. The apparatus as claimed in claim 1, characterized in that, The device is a compressor.

3. The apparatus as described in claim 1 or 2, characterized in that, It also includes a drive motor for rotating the rotating shaft in response to a first control signal from the controller.

4. The apparatus as claimed in any of the preceding claims, characterized in that, The device is a compressor, and the device controller limits the rotational speed of the rotating shaft to a speed greater than the takeoff speed.

5. The apparatus as claimed in any of the preceding claims, characterized in that, The controller is also configured to generate a first control signal to control the device to rotate at a predetermined operating rotation speed, and wherein the detection of the takeoff speed is in response to a sudden change in the frequency of a signal emitted by the device during a first time period.

6. The apparatus as claimed in any of the preceding claims, characterized in that, The device controller is configured to maintain the rotational speed of the rotating shaft above the takeoff speed during operation of the device.

7. The apparatus as claimed in any of the preceding claims, characterized in that, The sensor is at least one of an accelerometer and a displacement sensor.

8. The apparatus as claimed in any of the preceding claims, characterized in that, It also includes detecting the rotational speed of the rotating shaft, and wherein the rotational speed is used to determine the takeoff speed.

9. The apparatus as claimed in any of the preceding claims, characterized in that, The frequency of the signal and the corresponding rotational speed of the rotating shaft are stored in the memory.

10. The apparatus as claimed in any of the preceding claims, characterized in that, The device is a compressor equipped with an electric motor, wherein the electric motor is operable to maintain the operating rotational speed of the rotating shaft at a speed greater than the takeoff speed.

11. A method for determining the takeoff speed of an air foil bearing, comprising: Control the rotation of a device having a rotating shaft supported by multiple air foil bearings at a predetermined operating speed; Disconnect the drive source connected to the rotating shaft, causing the rotating shaft to begin a coasting deceleration phase from its maximum operating rotational speed to zero rotational speed; During multiple times within the coasting deceleration phase, at least one of the frequency and amplitude of the device's vibration, as well as the rotational speed of the rotating shaft, is detected by sensors. The takeoff speed of the air foil bearing is determined by the test controller responding to multiple frequencies; as well as The takeoff speed is stored in a memory that is communicatively connected to the device.

12. The method for determining the takeoff speed of an air foil bearing as described in claim 11, characterized in that, The device is a compressor.

13. The method for determining the takeoff speed of an air foil bearing as described in claim 11 or 12, characterized in that, The takeoff speed is determined in response to the change in the frequency of the vibration caused by the contact event of the air foil bearing foil.

14. The method for determining the takeoff speed of an air foil bearing as described in any one of claims 11 to 13, characterized in that, The takeoff speed is determined in response to the change in the frequency of the vibration caused by the contact event of the air foil bearing foil.

15. The method for determining the takeoff speed of an air foil bearing as described in any one of claims 11 to 14, characterized in that, The takeoff speed is determined in response to changes in the slope of the ratio of multiple detected frequencies at multiple associated rotational speeds.

16. The method for determining the takeoff speed of an air foil bearing as described in any one of claims 11 to 15, characterized in that, The device is a compressor driven by an electric motor, wherein the compressor controller controls the rotational speed of the electric motor in response to the takeoff speed, such that the compressor operates at an operating rotational speed greater than the takeoff speed.

17. The method for determining the takeoff speed of an air foil bearing as described in any one of claims 11 to 16, characterized in that, The method is performed during end-of-line testing operations.

18. The method for determining the takeoff speed of an air foil bearing as described in any one of claims 11 to 17, characterized in that, The sensor is an accelerometer.

19. A compressor testing system, comprising: A rotation sensor for measuring the rotational speed of a compressor shaft supported by an air foil bearing; A sensor for measuring at least one of the frequency and amplitude of vibrations generated in response to rotation of the compressor shaft; A controller is configured to determine the takeoff speed of the air foil bearing in response to the frequency of the vibration and the rotational speed measured at multiple times during the transition between a first rotational speed and a second rotational speed. as well as A compressor controller is used to control the operation of the compressor so that the operating rotational speed of the compressor shaft is greater than the takeoff speed.

20. The compressor testing system as described in claim 19, characterized in that, It also includes a data interface for storing data, including the takeoff speed, in a memory accessible by the compressor.

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