阅读说明：本技术 X射线管诊断系统 (X-ray tube diagnostic system ) 是由 M·里奇默德 G·F·维沙普 D·琼斯 于 2019-06-28 设计创作，主要内容包括：一些实施方案包括一种系统,其包括：外壳,所述外壳被配置来封闭真空；阴极,所述阴极设置在所述外壳内；阳极,所述阳极设置在所述外壳内,所述阳极被配置来从所述阴极接收电子的射束；电机,所述电机设置在所述外壳内并且被配置来响应于驱动输入而旋转所述阳极；以及电路,所述电路电连接到所述驱动输入并且被配置来基于所述驱动输入的电压和所述驱动输入的电流来生成相位信号,所述相位信号指示所述驱动输入的所述电压与所述驱动输入的所述电流之间的相位差。(Some embodiments include a system, comprising: a housing configured to enclose a vacuum; a cathode disposed within the housing; an anode disposed within the housing, the anode configured to receive a beam of electrons from the cathode; a motor disposed within the housing and configured to rotate the anode in response to a drive input; and a circuit electrically connected to the drive input and configured to generate a phase signal based on a voltage of the drive input and a current of the drive input, the phase signal indicating a phase difference between the voltage of the drive input and the current of the drive input.)

1. A system, comprising:

a housing configured to enclose a vacuum;

a cathode disposed within the housing;

an anode disposed within the housing, the anode configured to receive a beam of electrons from the cathode;

a motor disposed within the housing and configured to rotate the anode in response to a drive input; and

a circuit electrically connected to the drive input and configured to generate a phase signal based on a voltage of the drive input and a current of the drive input, the phase signal indicating a phase difference between the voltage of the drive input and the current of the drive input.

2. The system of claim 1, wherein:

the drive input is a three-phase input comprising a first voltage, a second voltage and a third voltage, each voltage having a phase difference with the other voltages;

the circuit further includes a first comparator configured to generate a first pulse based on a comparison with the first voltage and the second voltage; and is

The circuit is configured to generate the phase signal based on the first pulse.

3. The system of claim 2, wherein the circuitry further comprises:

a second comparator configured to generate a second pulse based on a current associated with the first voltage; and

a logic circuit configured to generate the phase signal in response to the first pulse and the second pulse.

4. The system of claim 1, wherein:

the drive input is a single phase input;

the voltage of the drive input is a voltage of the single-phase input; and is

The current of the drive input is the current of the single phase input.

5. The system of claim 1, further comprising a diagnostic circuit configured to receive the phase signal and generate an indication of a state of the motor in response to the phase signal.

6. The system of claim 5, further comprising:

a rotatable housing comprising the housing; and

an accelerometer configured to measure acceleration of the rotatable gantry;

wherein the diagnostic circuit is configured to generate an indication of the state of the motor in response to the acceleration of the rotatable gantry.

7. The system of claim 5, wherein the diagnostic circuitry is configured to:

comparing the phase signal to a range based on a previous state of the phase signal; and is

Generating an indication of the state of the motor in response to the comparison.

8. The system of claim 7, wherein:

the range is based on at least one of a rotational frequency of the motor and a centrifugal acceleration of a rotatable gantry comprising the housing.

9. The system of claim 5, wherein the diagnostic circuitry is further configured to:

measuring a time from an initiation to a steady state of the phase signal; and is

Generating an indication of the state of the motor in response to the time from the initiation of the phase signal to a steady state.

10. The system of claim 5, wherein the diagnostic circuitry is further configured to:

measuring a rate of change of the phase signal from startup to steady state; and is

Generating an indication of the state of the motor in response to the rate of change of the phase signal from a start to a steady state.

11. A system, comprising:

a housing configured to enclose a vacuum;

a cathode disposed within the housing;

an anode disposed within the housing, the anode configured to receive a beam of electrons from the cathode;

a motor disposed within the housing and configured to rotate and receive a drive input;

a sensor and configured to receive a signal from the motor; and

a circuit electrically connected to the sensor and configured to generate an indication of a state of the motor in response to the signal received from the motor.

12. The system of claim 11, wherein the circuitry is configured to:

measuring a time from a cessation of power supplied to the motor until the signal from the motor exceeds a threshold; and is

Generating an indication of the state of the motor in response to the time.

13. The system of claim 12, wherein:

the sensor is an acoustic sensor; and is

The signal received from the motor is an acoustic signal sensed by the acoustic sensor.

14. The system of claim 12, wherein:

the sensor is a voltage sensor; and is

The signal received from the motor is a voltage sensed by the voltage sensor.

15. The system of claim 12, wherein:

the sensor is a current sensor coupled to the cathode; and is

The signal received from the motor is a current sensed by the current sensor.

16. The system of claim 11, wherein the circuitry is configured to:

measuring a time from supplying power to the motor until the signal from the motor reaches a steady state; and is

Generating an indication of the state of the motor in response to the time.

17. The system of claim 11, wherein the signal from the motor is a phase shift between a voltage driving the motor and a current associated with the voltage.

18. The system of claim 11, wherein the circuitry is configured to:

measuring a rate of change of the signal from the motor from supplying power to the motor until the signal from the motor reaches a steady state; and is

Generating an indication of the state of the motor in response to the rate of change.

19. A system, comprising:

means for operating a motor located within an evacuated envelope of the x-ray tube;

means for measuring a phase shift between a voltage and a current of the drive motor during operation; and

means for generating an indication of a state of the motor in response to the phase shift.

20. The system of claim 19, further comprising:

means for changing an operating condition of the x-ray tube to a new operating condition; and

means for generating an indication of the state of the motor in response to the new operating condition.

Background

The present disclosure relates to x-ray tubes, systems including x-ray tubes, and diagnostic techniques for such tubes and systems.

X-ray tubes are used in a variety of applications. Some x-ray tubes have rotating structures, such as rotating anodes. The anode is rotated by a motor contained within the vacuum housing of the x-ray tube. Over time, the motor may malfunction and thus cause the x-ray tube to malfunction. When the x-ray tube fails, it can be replaced. However, there may be no warning about the failure.

Description of the drawings

Fig. 1A-1B are block diagrams of systems according to some embodiments.

Fig. 2A is a block diagram of a system having three-phase power, according to some embodiments.

Fig. 2B is a block diagram of an example of the sensor and phase detector of fig. 2A, according to some embodiments.

Fig. 2C is a graph illustrating an example of voltage, current, and logic signals in the circuit of fig. 2B.

Fig. 3A-3C are graphs illustrating examples of signals used in diagnostic x-ray tubes according to some embodiments.

Fig. 4 is a block diagram of a system with single phase power according to some embodiments.

Fig. 5A-5C are examples of systems with various motor sensors according to some embodiments.

Fig. 6 is a graph illustrating an example of a signal used in a diagnostic x-ray tube according to some embodiments.

Fig. 7 is a block diagram of a system with a combination of sensor types according to some embodiments.

Fig. 8 is a flow diagram illustrating a startup diagnostic process according to some embodiments.

Fig. 9 is a flow diagram illustrating a shutdown diagnostic process according to some embodiments.

Fig. 10 is a flow diagram illustrating an operational diagnostic process according to some embodiments.

Fig. 11 is a block diagram of a Computed Tomography (CT) gantry according to some embodiments.

Fig. 12 is a block diagram of a 2D x radiographic imaging system, according to some embodiments.

Detailed Description

Failure of the x-ray tube can result in interruption processes and/or undesirable downtime while waiting for the x-ray tube to be replaced. For example, the system integrator may treat the x-ray tube similarly to the bulb, i.e., replace the x-ray tube when it fails. The time from failure to replacement can result in undesirable interruptions and/or downtime, particularly when an x-ray tube unexpectedly fails. However, by monitoring the x-ray tube to predict failure of the x-ray tube as described herein, interruptions and/or undesirable downtime may be reduced or eliminated. As will be described in further detail below, in some embodiments, various parameters of the motor within the x-ray tube may be monitored directly or indirectly and may be used to predict failure of the x-ray tube. This alert may allow for scheduled replacement of the x-ray tube, such as during periods when the system including the x-ray tube is not in use. Thus, the up-time of the x-ray system may be increased.

Fig. 1A-1B are block diagrams of systems according to some embodiments. Referring to fig. 1A, in some embodiments, a system 100a includes an enclosure 101 configured to enclose a vacuum. This housing 101 may be the housing of the x-ray tube 103. Disposed within the housing 101 are a cathode 102, a rotatable anode 106, and a motor 110.

The cathode 102 is configured to generate an electron beam 104. Other structures, circuitry, etc. may be present to generate, form, and/or direct beam 104. For example, beam focusing and positioning magnets may be disposed in the housing 101 relative to the cathode 102 to produce the desired electron beam 104. For simplicity, such components are not shown.

The beam 104 is directed towards an anode 106. The anode 106 is a rotatable anode 106 configured to be rotated by a motor 110. The rotatable anode 106 is configured to receive the beam 104 and generate x-rays 108 in response.

The motor 110 is disposed within the housing 101. The motor 110 is configured to receive a drive input 116 from a motor driver 118. Drive input 116 is a power input for driving motor 110. In some embodiments, the motor 110 is an induction motor; however, in other embodiments, other types of motors may be used.

The system 100a also includes diagnostic circuitry 114. Diagnostic circuitry 114 is circuitry that includes inputs for one or more sense signals 112, such as sense voltages, currents, accelerations, rotational speeds, etc., associated with system 100 a.

The diagnostic circuitry 114 may be disposed at least partially or completely outside the housing 101. The diagnostic circuit 114 is electrically connected to a drive input 116 for the motor 110. Here, the diagnostic circuit 114 is configured to receive the sense signal 112 from the drive input 116. The diagnostic circuitry 114 may be electrically connected to cables connecting the motor driver 118 to the motor 110, to terminals of the motor 110 at the wall of the housing 101, to the motor driver 118, and so forth.

The diagnostic circuitry 114 may include a general purpose processor, a Digital Signal Processor (DSP), an application specific integrated circuit, a microcontroller, a programmable logic device, discrete circuitry, a combination of such devices, and the like. The diagnostic circuitry 114 may be a stand-alone circuit or may be partially or wholly integrated with other control systems of the system 100 a. For example, the diagnostic circuitry 114 may be part of an x-ray tube controller, a system controller, or the like. The diagnostic circuitry 114 may be coupled to a communication module (not shown) that provides an output of the diagnostic circuitry 114 to a user or other entity to provide status information, notify a user of a proposed replacement, and the like. The communication module may be part of an x-ray tube controller, a system controller, or the like. The diagnostic circuit 114 may also include memory, such as Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory, and the like. The diagnostic circuitry 114 may be configured to store configuration information, historical measurements, diagnostic information, and the like in memory. The diagnostic circuitry 114 may also include a timer, comparator, etc.

In some embodiments, the diagnostic circuitry 114 includes sensors configured to sense voltage, current, sound, vibration, and the like. In other embodiments, diagnostic circuitry 114 is coupled to such sensors. In other embodiments, such sensors are distributed between diagnostic circuitry 114 and other circuitry. Various embodiments of the sensor separate from the diagnostic circuitry 114 will be described below; however, in other embodiments, the sensors may be distributed as described above.

As will be described in further detail below, the diagnostic circuit 114 may be configured to receive or generate a phase signal based on the voltage of the drive input 116 and the current of the drive input 116. The phase signal is indicative of a phase difference between the voltage of the drive input 116 and the current of the drive input 116. In an induction motor, the phase signal may indicate a load or change in load of the motor 110.

Referring to fig. 1B, system 100B may be similar to system 100a and include similar components. The motor 110 may include a rotor 110a, a stator 110b, and a bearing 110 c. The rotor 110a may be coupled to the rotatable anode 106 such that when the rotor 110a rotates, the rotatable anode 106 rotates. The rotor 110a is rotatably coupled to the stator 110b by a bearing 110 c. These bearings 110c are examples of portions of the motor 110 that may wear and ultimately cause the system 100b to fail.

In some motors 110, the stator 110b and rotor 110a are inductively coupled, such as in an induction motor. Therefore, there is a phase difference between the driving current in the winding of the stator 110b and the driving voltage that drives the current. In particular, the phase difference between the stator 110b driving voltage and current may vary due to bearing wear. The stator 110b resistance has a real component and an imaginary component. The real component is primarily the resistance of the stator 110b windings. The imaginary component is due to inductive coupling with the rotor 110 a. The inductive resistance may be related to the frequency of the power supplied to the stator 110b and the rotational frequency of the rotor 110 a.

The motor 110 may cause the rotatable anode 106 to rotate at various different speeds. For example, motor 110 may cause rotatable anode 106 to rotate at a frequency between 1Hz and 200 Hz. In another example, the frequency may be between 50Hz and 180 Hz. This rotation may spread the instantaneous power of the beam 104 received by the rotatable anode 106 over a larger effective area. Since the motor 110 and the rotatable anode 106 are continuously rotating to achieve the effect of expanding the power of the beam 104, failure of the motor 110, and in particular the bearing 110c, can cause the x-ray tube 103 including the motor 110 to fail.

Measuring and identifying changes in the operation of the bearing 110c can be used to predict the end of life of the bearing 110c, and thus the end of life of the motor 110 and the x-ray tube 103. For fixed operating conditions, changes in the relative phases of the current and voltage of the drive input 116 of the motor 110 may indicate a change in the state of the bearing 110 c. The change may include increased wear resulting in more friction. The magnitude of the relative phase may increase as wear increases to overcome the increased friction.

Predicting bearing failure in the x-ray tube 103 may be more difficult or impossible when compared to other environments. Within the operating environment of the x-ray tube 103, sensors may be difficult or impossible to implement. For example, the voltage within the x-ray tube 103 may be on the order of tens to hundreds of kilovolts (kV) or higher. The x-ray tube 103 may be subject to high heat, such as from the cathode 102, heater, etc. In addition, the moving parts of the motor 110 may be surrounded by non-conductive or high resistivity oil for cooling purposes. The x-ray tube 103 may be subjected to high magnetic fields. The x-ray tube 103 may be metallic and may prevent external sensing of internal structures by optical or magnetic techniques. Furthermore, if a rotating structure is used to sense properties of the motor 110, high electric fields within the x-ray tube 103 may introduce arcing problems. A sensor or other sensor capable of determining the top dead center of the rotor 110a may be mounted on the motor 110 in a case where the motor is not subjected to high vacuum, high heat, high voltage, magnetic field, or the like.

By using the system described herein, the sensor can be placed in a less harsh environment. Further, in some embodiments, the systems described herein may be coupled to a conventional x-ray tube, and information may be obtained and a relevant prediction may be generated. That is, no changes to the x-ray tube 103, and in particular, to the internal components and structure of the x-ray tube 103, may be required to achieve the benefits of the systems described herein.

In some embodiments, the diagnostic circuitry 114 is configured to sense any faults that increase the load on the motor 110. A change in the phase shift between the drive current and the voltage may indicate that some reason has resulted in an increase in the load on the motor 110. As will be described in further detail below, the phase may be compared to a calibrated value or range for a particular set of operating conditions. In some embodiments, a value or range may be provided for each set of operating conditions, which may result in different values or ranges being produced during normal operation. In a particular example, a value or range of phases may be set for each combination of anode 106 frequency and gantry centrifugal acceleration. If the phase changes from a particular value or exceeds a particular range, this change may indicate a fault, such as excessive wear on the bearing 110 c.

Fig. 2A is a block diagram of a system having three-phase power, according to some embodiments. The motors may be configured in a delta (Δ) or wye (Y or star) configuration. Fig. 2B is a block diagram of an example of the sensor and phase detector of fig. 2A, according to some embodiments. Referring to fig. 2A-2B, in some embodiments, the system 200 may be similar to the system 100a or 100B of fig. 1A or 1B. However, the motor drive 118 is a three-phase motor drive 218. The three-phase motor driver 218 is a circuit configured to generate the drive input 216 with three sinusoidal drive voltages 216-1 through 216-3 each phase shifted by about 120 degrees. The motor 110 is a three-phase motor configured to operate using such three-phase voltages.

The voltage and current (V/I) sensor 220 is configured to sense one or more voltages and one or more currents driving the input 216. The specific example of FIG. 2B includes one current sensor 220-1 and two voltage sensors 220-2 and 220-3.

The current sensor 220-1 may be any kind of circuit that may generate a signal based on a current. For example, the current sensor 220-1 may be a Hall effect sensor, a series resistor, a circuit for converting a voltage drop measured across a resistor, and the like. The current sensor 220-1 is configured to sense current flowing through the connection between the three-phase motor driver 218 and the motor 110 to which the drive voltage 216-3 is applied.

The voltage sensors 220-2 and 220-3 may be any kind of circuit that may generate a signal based on a voltage. For example, voltage sensors 220-2 and 220-3 may include chip resistors, transformers, and the like. The voltage sensor 220-2 is configured to sense a voltage of the drive voltage 216-2 to generate a voltage signal 222-2. Similarly, voltage sensor 220-3 is configured to sense a voltage of drive voltage 216-3 to generate voltage signal 222-3. The sensor 220 described herein may also include other circuitry for converting current, voltage, etc. appropriately into a form suitable for downstream circuitry.

In some embodiments, the V/I sensor 220 may be part of a power cable between the three-phase motor drive 218 and the motor 110. However, in other embodiments, one or more V/I sensors 220 may be disposed in other locations and/or distributed between the power cable and other circuitry.

V/I phase detector 224 is a circuit configured to generate a phase signal 226 indicative of the relative phases of the voltage and current. The specific example of FIG. 2B includes two comparators 224-1 and 224-2. Comparators 224-1 and 224-2 are each configured to generate a digital output based on a comparison of the two signals. Comparator 224-1 is configured to compare sense voltage signal 222-2 with sense voltage signal 222-3. Output 225-1 is a digital signal indicative of a larger sense voltage signal. Thus, output 225-1 is a pulse train that switches when sinusoidal drive voltages 216-2 and 216-3 cross. Thus, the output 225-1 has a particular phase relationship with the drive voltage 216-3.

Comparator 224-2 is configured to compare sensed current signal 222-1 to threshold 224-4. In some embodiments, threshold 224-4 is ground; however, in other embodiments, the threshold 224-4 may be different. As a result of the comparison, output 225-2 is a pulse train that switches when the current associated with drive voltage 216-3 exceeds threshold 224-4. Thus, the output 225-2 has a particular phase relationship with the current associated with the drive voltage 216-3.

Both outputs 225-1 and 225-2 are combined in and gate 224-3. The output 226 is a phase signal 226 having pulses with widths that represent the phase shift between the drive voltage 216-3 and the associated current.

Fig. 2C is a graph illustrating an example of voltage, current, and logic signals in the circuit of fig. 2B. An example of a sense current 222-1 associated with a drive voltage 216-3 and examples of sense voltages 222-2 and 222-3 corresponding to two drive voltages 216-2 and 216-3 are shown. The sense drive voltages 222-2 and 222-3 are 120 degrees out of phase. The sense current 222-1 is out of phase with the associated sense drive voltage 222-3 by a phase shift 227. In particular, the sense current 222-1 is lagging the sense drive voltage 222-3 by the phase shift 227.

Output 225-1 is a pulse train having transition points aligned with the intersection of sense drive voltages 222-2 and 222-3. Output 225-2 is a pulse train having a transition point aligned with the zero crossing point of sense current 222-1. Output 226 is the result of the logical AND of outputs 225-1 and 225-2. The resulting pulse has a width 229. This width depends on the relative phase 227. As the phase lag of sense current 222-1 increases (i.e., phase 227 increases), the rising edge of output 225-2 will have a correspondingly increasing lag. Thus, the leading edge of the pulse in output 226 will have a correspondingly increased amount of hysteresis, thereby increasing the pulse width 229.

In some implementations, the pulse in the output 226 will have a non-zero width 229 even if there is a zero phase shift between the sense drive voltage 222-3 and the sense current 222-1. However, in other embodiments, the circuitry may be configured differently. Further, while a particular polarity of the signal and two particular voltages 216-2 and 216-3 have been used as examples, in other embodiments, different polarities and different voltages may be used. Although the absolute value of the pulse width 229 may be different, a relative change and/or absolute value may still be detected.

As described above, this phase shift 227 may represent the load on the motor 110. The phase shift 227 is encoded in the pulse width 229 of the phase signal 226. The diagnostic circuitry 114 may be configured to measure the pulse width 229. Thus, the diagnostic circuit 114 has available values representing the relative or absolute phase of the current and voltage of the drive input 116, which can be used for diagnostic purposes. For example, the diagnostic circuitry 114 may include a microcontroller, specific circuitry, software, etc. to convert the pulses of the phase signal 226 into digitized values. In a particular example, each of the rising and falling edges of the pulse may trigger a reading of the clock value. The difference of these two corresponding values may indicate the pulse width 229 and thus the phase shift 227.

The diagnostic circuitry 114 may be configured to further process or accumulate the phase signal 226. For example, the diagnostic circuitry 114 may be configured to output a running average of the pulse width of the phase signal 226 over a one second interval. In another example, the widths of all pulses less than phase signal 226 may be digitized. In other embodiments, other processing techniques may be performed.

In some embodiments, the two voltages 216-2 and 216-3 are sensed and compared to reduce noise. For example, comparing voltages 216-2 and 216-3 will provide phase information because the relative phases of the two voltages are fixed. However, the common mode noise present on both may be reduced or eliminated.

Although a specific example of V/I phase detector 224 has been described, in other embodiments, other circuits may be used. Any circuit that can generate pulses with widths indicative of relative phase can be used as V/I phase detector 224. Furthermore, the output need not be in the form of a pulse. For example, output 226 may be an analog signal or a digital signal indicating the relative phase. In some implementations, the pulses in the phase signal 226 may be filtered with a low pass filter to generate an analog phase signal.

In some embodiments, the V/I phase detector 224 may be implemented in the diagnostic circuitry 114. For example, diagnostic circuitry 114 may include digitizing circuitry (such as an analog-to-digital converter) to digitize each of sense current 222-1 and sense voltages 222-2 and 222-3. The diagnostic circuitry 114 may be configured to perform operations similar to those performed by the V/I phase detector 224. Further, diagnostic circuitry 114 may have other properties available to drive input 216, such as the frequency of voltage 216, the magnitude of the current of one or more voltages 216, and so forth.

Fig. 3A-3C are graphs illustrating examples of signals used in diagnostic x-ray tubes according to some embodiments. Using techniques similar to those described herein, the diagnostic circuitry 114 may be configured to generate an indication of the state of the motor 110. Fig. 3A is a graph illustrating an example of a phase 300 for a set of operating conditions. The phase 300 may be the digitized pulse width 229 that has been acquired and processed as described above. For example, the phase 300 may be the width of the pulse 229 in milliseconds (ms).

In some implementations, the diagnostic circuitry 114 compares the phase 300, which represents the relative phase shift between the drive voltage 216 and the corresponding current, to one or more ranges. In some embodiments, the system may be calibrated to determine one or more ranges. In other embodiments, the initial steady state of the phase 300 may be used to generate one or more ranges. Here, the first range 302 represents an acceptable operating range given particular operating conditions. In a particular example, a well-conditioned system may be operable to generate a baseline phase shift. This phase shift may be used to generate a range 302 representing an acceptable range. In some embodiments, range 302 is a range as follows: if the system continues to operate within this range 302 for a particular operating condition, the system may operate indefinitely with respect to the monitored components.

Range 304 represents the operating range of phase 300 in which a fault may occur in a predictable amount of time. If the measured phase 300 changes into range 304, diagnostic circuitry 114 may predict that the system will soon fail. The diagnostic circuitry 114 may generate a predicted remaining useful life. For example, after the phase 300 of the system enters the range 304, the diagnostic circuitry 114 may access statistics regarding the remaining useful life. In a particular example, the system may combine the mean time to failure (mean time to failure) from entering the range 304 minus zero or more standard deviations from the statistical data.

In some implementations, the phase 300 may be out of range 304. Outside ranges 302 and 304 may represent phase shifts where the system is failing or has failed for a given operating condition.

In fig. 3A, times T1 and T2 are used as examples of times at which phase 300 is shifted out of range 302 and out of range 304, respectively. For example, at the beginning of operation, phase 300 may be within range 302. At this point, the system may not have a predictable remaining useful life. However, at about time T1, some conditions change (such as increased wear on the motor bearings), which causes the phase 300 to change moving out of the range 302. At this point, the system may have a limited predictable remaining useful life.

The system may operate under such conditions; however, at some point, wear may increase causing the system to malfunction. Time T2 represents the point at which phase 300 moves out of range 304. The difference between times T1 and T2 may be specific to a given system. That is, while the difference may relate to the predicted remaining useful life, the actual remaining useful life may be different.

The relative sizes of times T1 and T2 may be different than shown. For example, time T1 may be relatively large compared to the time between time T2 and time T1. Here, time is for illustration only.

In some implementations, the diagnostic circuitry may filter or otherwise process the phase 300 to remove false positives. For example, if an expected transient change in the phase 300 may cause the phase 300 to move out of the range 302 or 304, the diagnostic circuit 114 may filter the phase 300 to ignore or reduce the effects of such transients.

As described above, phase shift 300 may depend on particular operating conditions. Using the anode 106 rotational frequency and gantry centripetal acceleration as examples of operating conditions, the diagnostic circuitry 114 may include ranges 302 and 304 specific to each combination of rotational frequency and gantry centripetal acceleration. In other embodiments, for a given set of operating conditions, equations may be used to generate ranges 302 and 304. In other embodiments, ranges 302 and 304 may be based on interpolation between ranges 302 and 304 for a limited set of operating conditions. Ranges 302 and 304 may be generated in other ways. Further, although two ranges 302 and 304 are used as examples, in other embodiments, one range or more than two ranges may be used.

Although anode rotational frequency and gantry centripetal acceleration have been used as examples of operating conditions that may affect the phase shift 300 in normal operation, in other embodiments, other conditions may be used in addition to or instead of one or more of these examples. For example, gantry rotational speed, motor 110 drive frequency, motor 110 drive voltage, or other operating conditions may be used as the operating conditions affecting ranges 302 and 304, or similar ranges.

FIG. 3B is a graph illustrating a diagnostic technique using a phase change from start-up. Two exemplary phases 300a and 300b are shown. Phase 300a is an example of a phase measured from a system operating normally. Phase 300b is an example of a phase measured from a system with a limited predicted remaining useful life, is failing, or has failed.

In particular, phase 300a reaches steady state through time T3 from start-up and has a certain maximum rate of change of phase 300a at 300 a-1. Similarly, phase 300b reaches steady state over time T4 from start, which time T4 is longer than time T3. In addition, the phase 300b has a maximum rate of change 300b-1 that is less than the rate of change 300 a-1.

The steady state can be defined in a number of ways. For example, a steady state may be an absolute change from one measurement to the next, the absolute change being below a threshold. In another example, the steady state may be a relative change that is less than a threshold, such as a percentage change from start-up. In another example, a change over time below a threshold may indicate a steady state. In another example, the magnitude of the derivative of the measured signal over time or the magnitude of the derivative of the difference between the measured signal and the expected signal below a threshold may indicate a steady state.

One or both of the time to reach steady state and the rate of change of the phase may be similar to or used in addition to the steady state value described above. For example, the diagnostic circuitry 114 may include a threshold time T_th1And T_th2. Threshold time T_th1A boundary value between a system operating normally and a system that may be or is in the process of failing is defined. Threshold time T_th2A given residual may be definedThe boundary value between a system that may fail during its lifetime and a system that is in the process of failing or has failed. Thus, under a given set of operating conditions, a different aspect of the phase may be another indicator of the bearing state.

Referring back to fig. 2B, in some embodiments, diagnostic circuitry 114 may be configured to receive sensed current value 222-1. The dotted lines represent optional connections. As described above, diagnostic circuitry 114 may be configured to digitize sense current 222-1. FIG. 3C is a graph illustrating a diagnostic technique using a change in current from start-up. Similar to the time to reach steady state and the rate of change of the phase described above with respect to fig. 3B, the time to reach steady state and the rate of change of the current may be used as an indicator of the state of the motor and/or system. For example, current 315a represents the current driving motor 110 from startup to steady state, with the maximum rate of change 315 a-1. The time to reach the steady state is time T5. Similarly, current 315b represents the current of drive motor 110 from startup to steady state over time T6, which has a maximum rate of change 315 b-1. Current 315a represents the system being operated normally. Current 315b represents the current in the system that may be malfunctioning or in the process of malfunctioning. Similar to FIG. 3B, the threshold time T_th3Can be used to distinguish between systems that are operating normally and systems that may be failing. Another threshold time T_th4It can also be used to distinguish between systems with a limited predictable remaining useful life and those systems that are failing or have failed. Here, time T5 is less than threshold time T_th3And indicates that the associated system is operating normally. Time T6 is greater than threshold time T_th3And is less than threshold time T_th4The indicator system may have a limited predictable remaining useful life.

Although the change in phase or current has been shown in fig. 3A-3C as changing in a particular direction over time, in other embodiments the change may be made in the opposite direction. Further, the direction of change may also be changed based on the operating conditions.

Fig. 4 is a block diagram of a system with single phase power according to some embodiments. The system 400 may be similar to the system 200 of fig. 2A, and have similar corresponding components; however, the system 400 includes a single phase motor drive 418. The single-phase motor drive 418 is configured to generate a single-phase drive input 416. The V/I sensor 420 is configured to generate a sense current and a sense voltage as a sense signal 422. V/I phase detector 424 is configured to compare the phases of sensed current and voltage signals 422 to generate phase signal 426. A circuit similar to that of fig. 2B may be used as V/I phase detector 424; however, the sense voltage 222-3 may be compared to a ground voltage or another fixed voltage to generate a signal having a transition point, the zero crossing point of the sense voltage 222-3. This signal may be anded with output 225-2 to generate phase signal 426 having a width that depends on the relative phases of the voltage and current of signal phase drive input 416. In other embodiments, different circuitry may be used to generate phase signal 426, and phase signal 426 may take forms other than encoding the pulse width with phase information.

Fig. 5A-5C are examples of systems with various motor sensors according to some embodiments. These examples show different sensors that can be used in a manner similar to the relative phase described above. In these systems, the sensor is disposed outside the housing 101 of the tube 103 and is configured to receive a signal from the motor 110. As will be described in further detail below, the signal from the motor 110 may take a variety of forms. In any event, since the signal may be indicative of a state of the motor 110 (such as a rotational speed), the time from when the motor 110 is turned off until the signal exceeds a threshold or reaches a steady state may be used as diagnostic information.

Referring to fig. 5A, system 500a may be similar to systems 100a, 100b, 200, and 400 described above. One or more V/I sensors 520a may also be similar to the corresponding V/I sensors 220 and 420. However, the one or more V/I sensors 520a may include one or more sensors that may be current sensors or voltage sensors. For example, in some embodiments, the one or more V/I sensors 520 may include only current sensors, in other embodiments may include only voltage sensors, and in still other embodiments may include both current sensors and voltage sensors.

In response to the one or more sense signals 522a from the one or more V/I sensors 520a, the diagnostic circuitry 514 may be configured to generate an indication of the state of the electric motor 110 in response to signals received from the electric motor 110. For example, the diagnostic circuitry 114 may be configured to predict remaining useful life and/or indicate whether the x-ray tube 103 has failed.

Referring to fig. 5B, the system 500B may be similar to the system 500a of fig. 5A; however, the system 500b includes a sensor 520b that is not electrically connected to the motor 110. For example, the sensor 520b may be an acoustic sensor, a vibration sensor, or the like. Accordingly, the sensor 520b may be configured to generate the signal 522b based on the rotation of the motor 110. In some embodiments, the sensor 520b may be isolated from other sources of structure or noise and/or vibration not associated with the motor 110 or the rotatable anode 106.

Referring to fig. 5C, in some embodiments, system 500C may be similar to system 500b described above. However, the sensor 520c may be configured to sense another aspect of the x-ray tube 103 that is indirectly affected by the motor 110 or the rotatable anode 106. For example, rotation of the motor 110 and/or the rotatable anode 106 may induce an electrical current in the filament of the cathode 102. The sensor 520c may be configured to sense this induced signal from the cathode 102. Although the induced signal sensed from cathode 106 has been used as an example, sensor 520c may be configured to sense an induced signal from another component of x-ray tube 103.

Fig. 5D is a graph illustrating an example of a signal used in diagnosing an x-ray tube according to some embodiments. The various sensors 520 described with respect to fig. 5A-5C may generate corresponding signals 522 that are received by the diagnostic circuitry 114. Similar to the time to steady state measurements of fig. 3B and 3C, the time to steady state, a zero value, or a suitable threshold value may be used to indicate the state of the motor 110 and/or the x-ray tube 103. In some embodiments, the motor 110 and the rotatable anode 106 may still rotate after the gantry has stopped rotating. The time until the motor 110 stops, the speed is below a certain threshold, or the direction is reversed may indicate a state of the motor 110, such as a wear state of the bearings.

Signal 526a represents signal 522 or a signal derived from a system that is operating normally. Similarly, signal 526b represents signal 522 or a signal derived from a system having a predictable limited remaining useful life. If the motor 110 is operating properly, the time until the motor 110 stops spinning, the speed exceeds a threshold, the noise or vibration level exceeds a threshold, etc. may be greater than a threshold time T_th5. Here, the time T7 associated with the signal 526a and the normally operating motor 110 is greater than the threshold time T_th5. However, time T8 associated with signal 526b is less than threshold time T_th5. Thus, the system generating signal 526b may have a predictable limited remaining useful life. Threshold time T_th6Also shown as an example of a threshold value for determining a system having a certain remaining useful life or a system that is failing or has failed.

In some embodiments, the measurement may be started at a time when the rotating gantry has stopped rotating. This time corresponds to the off time of fig. 5D. In some embodiments, power to the motor 110 may be maintained until the gantry has stopped rotating; however, in other embodiments, the power to the motor 110 may be turned off at substantially the same time.

In some embodiments, power to the motor 110 is turned off; however, in other embodiments, a relatively small amount of power may be applied to the motor 110 in a manner intended to reverse the direction of rotation of the motor 110. The time that the motor 110 stops or reverses direction may be measured. In some embodiments, once the motor 110 reverses direction, the current and voltage relationships described above in fig. 2C will reverse. This can be used to determine when the motor has stopped or reversed direction.

Fig. 7 is a block diagram of a system with a combination of sensor types according to some embodiments. In some embodiments, system 700 may be similar to systems 100, 200, 400, and 500 a-c. That is, the system 700 may have a diagnostic circuit 714 electrically connected to the motor 110 and may be configured with various sensors and other circuitry as described with respect to the systems 100, 200, 400, and 500 a-c. In addition, diagnostic circuitry 714 is also coupled to another sensor 720. This sensor 720 is an operating condition sensor 720. For example, sensor 720 may be an accelerometer attached to tube 103 or a frame. In some embodiments, sensor 720 may be a single axis accelerometer configured to sense radial acceleration; however, in other embodiments, the accelerometer may be configured to sense acceleration in multiple axes. In other embodiments, the sensor 720 may be a frequency detector configured to detect the frequency of the drive input provided to the motor 110. In other embodiments, sensor 720 may be configured to generate sense signal 726 indicative of centripetal acceleration. In other embodiments, a plurality of such sensors 720 may be present and configured to generate a plurality of sensing signals 726.

The sensing signal 726 may be combined with data from sensors associated with the motor 110 and may be used to generate an indication of the state of the motor 110 as described above. For example, a sense signal 726 indicative of centripetal acceleration and a sense signal 726 indicative of rotational frequency of the motor 110 may be used to select particular thresholds, values, ranges, etc. to compare to the phases, currents, etc. as described above.

Fig. 8 is a flow diagram illustrating a startup diagnostic process according to some embodiments. Referring to FIG. 8 and the system of FIG. 1A as an example, the motor 110 is started at 800. For example, the motor 110 may be activated with a fixed magnitude drive input 116. At motor start in 800, a timer is started in 802. The timer may include circuitry, registers, software, etc. of the diagnostic circuitry 114. A loop is performed to measure a parameter at 804 and a determination is made at 806 as to whether the measured parameter (such as current, phase, rotational speed of the motor 110, etc.) has reached a steady state. For example, the diagnostic circuitry 114 may periodically acquire a new measurement parameter and process the measurement parameter in conjunction with a past measurement parameter to determine whether the measurement parameter has reached a steady state. As mentioned above, the steady state may be defined in various ways. 8

If the measured parameter has reached a steady state, the timer is stopped at 808. The value of the timer may then be used to generate an indication of the status at 810. For example, the measured parameter may be a phase or current as described above. The time to reach steady state may be compared to an appropriate threshold to generate an indication of state at 810.

In some implementations, the measured parameters may be acquired over time while waiting for steady state in 806. For example, the values of the measured parameters over time may be stored in a memory of the diagnostic circuitry 114. The measured parameters over time may be analyzed to generate a rate of change that is used to generate the indication of the state at 812. The status indication may be generated by comparing the rate of change to a threshold similar to the comparison described above. This operation may be performed with the operation in 810 or as an alternative to the operation in 810.

Fig. 9 is a flow diagram illustrating a shutdown diagnostic process according to some embodiments. Referring to fig. 9 and the system of fig. 1A as an example, the motor 110 is turned off at 900. Some operations of fig. 9 may be similar to those of fig. 8. For example, a timer is started at 902. A loop is executed to measure the parameter at 904 and a determination is made at 906 as to whether the measured parameter is in a steady state. As described above, the measured parameters may include current, phase, rotational speed, vibration, sound, etc., associated with the motor 110. Alternatively or in addition, the measured parameter may be compared to a threshold at 906. If the measured parameter has reached a steady state or exceeded a threshold, the timer is stopped in 908 and an indication of the state is generated using the value of the timer in 910. Thus, the off time may be used to generate an indication of the state as described above.

Fig. 10 is a flow diagram illustrating an operational diagnostic process according to some embodiments. Referring to fig. 10 and the system of fig. 1A as an example, in some embodiments, the diagnostic process is performed during operation. In 1000, a parameter is measured. At 1002, a parameter is compared to a first range. If the parameter is within this range at 1004, the process continues by measuring the parameter again at 1000.

If the parameter is not within the first range at 1004, a potential or expected failure is indicated at 1006. At 1008, the parameter is compared to a second range. The second range may be a range indicating that the system has a predictable limited remaining useful life and has not failed. If the measured parameter is within the second range, the parameter is measured again at 1000 to continue the process. If the measured parameter is outside the second range, a fault is indicated in 1012. Here, operation continues, however, in other embodiments, operation may be stopped.

In some embodiments, the range may vary. Specifically, if the operating conditions change at 1014, the range changes at 1016. Thus, the range may be updated to reflect a new nominal range and predicted range based on the new operating conditions. As mentioned above, the range may be varied in various ways.

In some embodiments, the diagnostic information generated as described above may be used to begin a maintenance process before the x-ray tube 103 fails. Using the phases described above as specific examples, by tracking the phase shift over time, during start-up, during shut-down, etc., a prediction of whether and/or when the x-ray tube 103 is malfunctioning can be determined. This information can be used to schedule times to replace the x-ray tube 103 during scheduled down times to reduce the impact on normal operation.

Furthermore, the availability of information and the availability of digitized forms in lieu of actual failures allows for the transmission of information to various destinations and for various purposes. For example, an operator of the facility may use the information to schedule replacement of the x-ray tube 103 and/or schedule replacement during use suspension. In another example, a dispenser may monitor one or more such systems and schedule delivery and/or schedule replacement. In another example, statistical information may be collected from actual usage and associated predicted failures of multiple systems in the field and/or test setting.

Fig. 11 is a block diagram of a Computed Tomography (CT) gantry according to some embodiments. In some embodiments, the CT gantry includes an x-ray source 1102, a cooling system 1104, a control system 1106, a motor drive 1108, a detector 1110, an AC/DC converter 1112, a high voltage source 1114, and a gate voltage source 1116. The x-ray source 1102 may include the x-ray tube 113 as described above. The control system 1106, motor drive 1108, and the like may include the various sensors and diagnostic circuitry described above. Although certain components have been used as examples of components that may be mounted on a CT gantry, in other embodiments, other components may be different. Although a CT gantry is used as an example of a system that includes the sensors and diagnostic circuitry described herein, the sensors and diagnostic circuitry described herein may be used in other types of systems having a vacuum enclosure or other harsh environments with rotating internal structures.

Fig. 12 is a block diagram of a 2D x radiographic imaging system, according to some embodiments. Imaging system 1200 includes an x-ray source 1202 and a detector 1210. The x-ray source 1202 may include the x-ray tube 103 as described above. A control system 1030 connected to the x-ray source 1002 can include the various sensors and diagnostic circuitry described above. The x-ray source 1202 is disposed relative to the detector 1210 such that x-rays 1220 can be generated to pass through a sample 1222 and be detected by the detector 1210.

With reference to fig. 1-12, some embodiments include a system comprising: a housing 101, the housing 101 configured to enclose a vacuum; a cathode 102, the cathode 102 being disposed within the housing 101; an anode 106, the anode 106 disposed within the housing 101, the anode 106 configured to receive a beam of electrons from the cathode 102; a motor 110 disposed within the housing 101 and configured to rotate the anode 106 in response to a drive input 116, 216, 416, 516; and a circuit electrically connected to the drive inputs 116, 216, 416, 516 and configured to generate a phase signal 226 based on a voltage of the drive inputs 116, 216, 416, 516 and a current of the drive inputs 116, 216, 416, 516, the phase signal 226 being indicative of a phase difference between the voltage of the drive inputs 116, 216, 416, 516 and the current of the drive inputs 116, 216, 416, 516. In some embodiments, the circuitry is disposed outside the housing 101.

In some embodiments, the drive inputs 116, 216, 416, 516 are three-phase inputs including a first voltage, a second voltage, and a third voltage, each voltage having a phase difference with the other voltages; the circuit further includes a first comparator 224-1, the first comparator 224-1 configured to generate a first pulse based on a comparison with the first voltage and the second voltage; and the circuit is configured to generate the phase signal 226 based on the first pulse.

In some embodiments, the circuit further includes a second comparator 224-2, the second comparator 224-2 configured to generate a second pulse based on a current associated with the first voltage; and a logic circuit 224-3, the logic circuit 224-3 configured to generate the phase signal 226 in response to the first pulse and the second pulse.

In some embodiments, the drive inputs 116, 216, 416, 516 are single phase inputs; the voltage of the drive input 116, 416, 516 is the voltage of the single phase input; and the current of the drive input 116, 416, 516 is the current of the single phase input.

In some embodiments, the system further includes a diagnostic circuit 114, the diagnostic circuit 114 configured to receive the phase signal 226 and generate an indication of the state of the motor 110 in response to the phase signal 226.

In some embodiments, the system further comprises: a rotatable gantry 1000, said rotatable gantry 1000 comprising a housing 101; an accelerometer configured to measure acceleration of the rotatable gantry 1100; wherein the diagnostic circuitry 114 is configured to generate an indication of the state of the motor 110 in response to the acceleration of the rotatable gantry 1100.

In some embodiments, the diagnostic circuitry 114 is configured to: comparing the phase signal 226 to a range based on a previous state of the phase signal 226; and generating an indication of the state of the motor 110 in response to the comparison.

In some embodiments, the range is based on at least one of a rotational frequency of the motor 110 and a centrifugal acceleration of the rotatable gantry 1100 including the housing 101.

In some embodiments, the diagnostic circuitry 114 is further configured to: measuring the time from the start-up to steady state of the phase signal 226; and generating an indication of the state of the motor 110 in response to the time from the initiation of the phase signal 226 to a steady state.

In some embodiments, the diagnostic circuitry 114 is further configured to: measuring the rate of change of the phase signal 226 from startup to steady state; and generating an indication of the state of the motor 110 in response to the rate of change of the phase signal 226 from being initiated to a steady state.

A system, comprising: a housing 101, the housing 101 configured to enclose a vacuum; a cathode 102, the cathode 102 being disposed within the housing 101; an anode 106, the anode 106 disposed within the housing 101, the anode 106 configured to receive a beam of electrons from the cathode 102; a motor 110 disposed within the housing 101 and configured to rotate and receive a drive input 116, 216, 416, 516; a sensor and configured to receive a signal from the motor 110; and a circuit electrically connected to the sensor and configured to generate an indication of a state of the motor 110 in response to the signal received from the motor 110. In some embodiments, the sensor and the circuitry are disposed outside the housing 101.

In some embodiments, the circuitry is configured to: measuring a time from a cessation of power supplied to the motor 110 until the signal from the motor 110 exceeds a threshold; and generating an indication of the state of the motor 110 in response to the time.

In some embodiments, the sensor is an acoustic sensor; and the signal received from the motor 110 is an acoustic signal sensed by the acoustic sensor.

In some embodiments, the sensor is a voltage sensor; and the signal received from the motor 110 is a voltage sensed by the voltage sensor.

In some embodiments, the sensor is a current sensor coupled to the cathode 102; and the signal received from the motor 110 is the current sensed by the current sensor.

In some embodiments, the circuitry is configured to: measuring a time from supplying power to the motor 110 until the signal from the motor 110 reaches a steady state; and generating an indication of the state of the motor 110 in response to the time.

In some embodiments, the signal from the motor 110 is a phase shift between a voltage driving the motor 110 and a current associated with the voltage.

In some embodiments, the circuitry is configured to: measuring a rate of change of the signal from the motor 110 from supplying power to the motor 110 until the signal from the motor 110 reaches a steady state; and generating an indication of the state of the motor 110 in response to the rate of change.

Some embodiments include a method comprising: operating a motor 110 located within the evacuated enclosure 101 of the x-ray tube; measuring a phase shift between a voltage and a current of the drive motor 110 during operation; and generating an indication of a state of the motor 110 in response to the phase shift.

In some embodiments, the method further comprises: changing an operating condition of the x-ray tube to a new operating condition; and generating an indication of the state of the motor 110 in response to the new operating condition.

Some embodiments include a system, comprising: means for operating a motor located within an evacuated envelope of the x-ray tube; means for measuring a phase shift between a voltage and a current of the drive motor during operation; and means for generating an indication of a state of the motor in response to the phase shift.

Examples of such means for operating the motor located within the enclosed vacuum enclosure of the x-ray tube include motor drivers 118, 218, 418, and 518.

Examples of such means for measuring the phase shift between the voltage and current driving the motor during operation include diagnostic circuitry 114, V/I sensors 220 and 420, and V/I phase detectors 224 and 424.

An example of the means for generating an indication of the state of the motor in response to the phase shift includes a diagnostic circuit 114.

In some embodiments, the method further comprises: means for changing an operating condition of the x-ray tube to a new operating condition; and means for generating an indication of the state of the electric machine in response to the new operating condition.

Examples of the means for changing the operating condition of the x-ray tube to a new operating condition include motor drivers 118, 218, 418, and 518.

An example of the means for generating an indication of the state of the motor in response to the new operating condition includes diagnostic circuitry 114.

Although the structures, devices, methods, and systems have been described in terms of particular embodiments, those of ordinary skill in the art will readily recognize that many variations of the particular embodiments are possible, and accordingly, any variations should be considered within the spirit and scope of the disclosure. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.

Thus, the claims following this written disclosure are hereby expressly incorporated into this written disclosure, with each claim standing on its own as a separate embodiment. The present disclosure includes all permutations of the independent claims and their dependent claims. Furthermore, further embodiments which can be derived from the appended independent and dependent claims are also expressly incorporated into this written description. These additional embodiments are determined by: any one of the claims beginning with claim [ x ] and ending with the claim immediately preceding this claim is replaced by the phrase "dependent item of a given dependent claim", wherein the parenthetical term "[ x ]" is the number replaced with the most recently cited independent claim. For example, for the first claim set starting with independent claim 1, claim 3 may be dependent on either of claims 1 and 2, and these separate dependent claims yield two different embodiments; claim 4 may be dependent on any of claims 1, 2 or 3, and these separate dependent claims yield three different embodiments; claim 5 may be dependent on any of claims 1, 2, 3 or 4, and these separate dependent claims yield four different embodiments; and so on.

Reference in the claims to the term "first" in reference to a feature or element does not necessarily imply the presence of a second or further such feature or element. According to 35U.S.C. § 112Reference to elements in a device-plus-function form (if any) is intended to be interpreted as covering a corresponding structure, material, or acts described herein and their equivalents. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.