Methods and systems for power supply

Abstract

To solve the problem in which unexpected power outages may damage a number of components, such as an X-ray source or X-ray tube in a CT imaging system.SOLUTION: Various methods and systems are provided for a power supply system. In one example, a method and system includes a power distribution unit (PDU) configured to receive power from a main power source and an uninterruptible power supply (UPS), where the UPS is configured to directly power an output alternating current (AC) load after the main power source becomes unavailable, and the UPS is further configured to power an output high voltage direct current (HVDC) load via passing current through an autotransformer to boost the voltage and an AC / DC converter.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the subject matter disclosed herein relate to providing power to a medical imaging system in response to a mains power source failing due to a utility power outage. [Background technology]

[0002] A computed tomography (CT) imaging system may receive AC power from a mains power source, such as a utility power supply. The utility power supply may be connected to an electrical grid. Under several conditions, the mains power may be unavailable (i.e., unavailable to the CT imaging system), such as in response to a power outage or component failure, or because the mains power supply is unexpectedly interrupted.

[0003] Some components inside the CT imaging system, such as the X-ray source or X-ray tube, may need to be cooled during the shutdown process before the main power is disconnected from the CT imaging system. An unexpected power outage may damage some components, such as the X-ray source or X-ray tube, of the CT imaging system. To protect and extend the life of these components, it may be desirable to provide backup power during an unexpected power outage of the main power to maintain the cooling routines of the components even when the main power is no longer available. Summary of the Invention

[0004] This summary introduces concepts that are more fully described in the detailed description. This summary is not intended to identify essential features of the claimed subject matter or to limit the scope of the claimed subject matter.

[0005] In one aspect, a method and system includes a power distribution unit (PDU) configured to receive power from a mains power source and an uninterruptible power supply (UPS) configured to directly power output alternating current (AC) loads after the mains power source becomes unavailable, and the UPS further configured to power output high voltage direct current (HVDC) loads via a pass-through current through an autotransformer and an AC-DC converter that step up the voltage.

[0006] In another aspect, a computed tomography (CT) imaging system includes a gantry coupled to an output HVDC load, a power feed cabinet coupled to an output AC load, and a power distribution unit (PDU). The PDU is configured to receive power from one of a mains power source and an uninterruptible power supply (UPS), the UPS providing power to the HVDC load via an autotransformer when the mains power source is unavailable. A plurality of contactors and a timer are coupled to the PDU and the UPS. A controller having computer readable instructions stored in a memory controls the plurality of contactors based on the availability of the mains power source and inputs from the timer.

[0007] In yet another aspect, a method for a computed tomography (CT) imaging system executed via instructions stored in a memory of a controller includes, in response to mains power becoming unavailable, powering an output AC load directly via an uninterruptible power supply (UPS), waiting a time delay, and powering an output HVDC load via power coupled from the UPS via an autotransformer that steps up a voltage output from the UPS. In response to mains power becoming available, the system executes the instructions including waiting until tubes of the CT imaging system have cooled, and powering the output HVDC load via the mains power.

[0008] The foregoing brief description is provided to present various concepts in a simplified form that are further described in the detailed description. Such description is not intended to identify key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that follow the detailed description. Moreover, the claimed subject matter is not limited to embodiments that solve any of the shortcomings described above or anywhere in this disclosure. [Brief description of the drawings]

[0009] The present disclosure will be more fully understood from the following description of non-limiting embodiments read in conjunction with the accompanying drawings, in which:

[0010] [Figure 1] 1 is a schematic diagram of a computed tomography (CT) imaging system in accordance with one embodiment. [Diagram 2] FIG. 1 is a block diagram of an exemplary CT imaging system in accordance with one embodiment. [Figure 3A] 2 is a schematic diagram of the sequence of operations of a power circuit under normal operating conditions; [Figure 3B] 2 is a schematic diagram of the sequence of operations of a power circuit under normal operating conditions; [Figure 4A] 2 is a schematic diagram of the sequence of operations of a power circuit under normal operating conditions; [Figure 4B] 2 is a schematic diagram of the sequence of operations of a power circuit under normal operating conditions; [Figure 5A] 4 is a schematic diagram of the sequence of operation of the power and control circuits under a loss of power operating condition. [Figure 5B] 4 is a schematic diagram of the sequence of operation of the power and control circuits under a loss of power operating condition. [Figure 6A] 4 is a schematic diagram of the sequence of operation of the power and control circuits under a loss of power operating condition. [Figure 6B] 4 is a schematic diagram of the sequence of operation of the power and control circuits under a loss of power operating condition. [Figure 7A] 4 is a schematic diagram of the sequence of operation of the power and control circuits under a loss of power operating condition. [Figure 7B] 4 is a schematic diagram of the sequence of operation of the power and control circuits under a loss of power operating condition. [Figure 8A] 4 is a schematic diagram of the sequence of operation of the power and control circuits under a loss of power operating condition. [Figure 8B] 4 is a schematic diagram of the sequence of operation of the power and control circuits under a loss of power operating condition. [Figure 9] 4 is a schematic diagram of the sequence of operation of the power circuit and control circuit during a power restoration condition. [Figure 10A] 4 is a schematic diagram of the sequence of operation of the power circuit and control circuit during a power restoration condition. [Figure 10B] 4 is a schematic diagram of the sequence of operation of the power circuit and control circuit during a power restoration condition. [Figure 11] 1 illustrates a method for switching power to a CT imaging system in response to the availability or unavailability of power from a mains power source to control restoration of the CT imaging system to a mains power source. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The following description relates to an embodiment of a backup power system for an imaging system as shown in Figures 1 and 2. The backup power system for an imaging system may be configured as an uninterruptible power supply (UPS) coupled to a power distribution unit (PDU) of the imaging system. Figures 3-4(B) show diagrams of the electrical circuitry coupling between a mains or source of alternating current (AC) power and an uninterruptible power supply (UPS) to a power distribution unit (PDU) during normal operating conditions from when the CT imaging system is turned on until the system is ready to perform an imaging scan. Figures 5(A)-8(B) show diagrams of the electrical and control circuits during a power loss condition when the power source does not provide power to the imaging system and the UPS provides backup power. Figures 9-10(B) show diagrams of the electrical and control circuits during a power restoration condition during which the system changes from using the UPS for power to using the power source after the power source returns. Figure 11 shows a method of operating the UPS based on the availability of power from the mains power source.

[0012] In one example of the present disclosure, an imaging system may include a gantry. The gantry may include x-ray tube bearings, such as liquid bearings, and the bearings may be cooled after operation. Power, such as electrical energy, may be consumed to perform a cooling routine for the x-ray tube bearings in the gantry. If power is not provided to the imaging system (i.e., unavailable to the CT imaging system, for example due to a power loss or disconnection from the power source), a loss of gantry power may occur without cooling the bearings, resulting in degradation and / or reduced lifespan.

[0013] In many applications, an imaging system may be located near a UPS system configured to provide backup power to the imaging system's computer and console. However, the UPS system is not wired to provide power to the gantry to allow desired cooling prior to shutdown if the main power source is interrupted (e.g., fails). Additionally, the gantry may not be sized to power the computer, console, and gantry for an extended period of time.

[0014] The inventors have recognized these shortcomings and have found a way to adjust one or more electrical circuits between the UPS and the PDU to provide power from the UPS to the gantry when the mains power is unavailable. This eliminates the need for an additional power source apart from the existing UPS, reducing manufacturing and installation costs while also reducing the package size of the system. For example, by adding multiple contactors (e.g., switches), the power sources can be controlled to ensure that both feeds (e.g., UPS and mains power) do not provide power at the same time.

[0015] 1 through 10(B) show example configurations with various components relative to one another. If elements are shown to be in direct contact with or directly coupled to one another, such elements may, at least in one example, be referred to as being in direct contact with or directly coupled to one another. Similarly, elements shown to be abutting or adjacent to one another may, at least in one example, be abutting or adjacent to one another. As an example, components that are in contact with one another by sharing a surface may be referred to as being in contact with one another by sharing a surface. As another example, elements that are separated from one another by only a space between them, with no other components in between, may, at least in one example, be referred to as being in contact with one another. In yet another example, elements that are shown above or below one another, opposite one another, or to the left or right of one another may be referred to as being in contact with one another. Additionally, as shown in each figure, an uppermost element or point of an element may, at least in one example, be referred to as the "top" of the element, and a lowermost element or point of an element may, at least in one example, be referred to as the "bottom" of the element. As used herein, top-bottom, above-below, above and below, etc. may be relative to the vertical axis of the figure and may be used to describe the placement of elements of the figure relative to one another. As such, an element shown on top of another element is, in one example, placed vertically above the other element. As yet another example, shapes of elements shown within a figure may be referred to as having these shapes (e.g., circular, rectilinear, flat, curved, rounded, chamfered, angled, etc.). Furthermore, elements shown intersecting one another may, in at least one example, be referred to as intersecting elements or intersecting one another. Still further, an element shown within another element or outside another element may, in one example, be referred to as such.

[0016] Although a CT imaging system is described as an example, it should be understood that the methods and systems of the present invention may also be usefully applied to other imaging systems, such as x-ray imaging systems, magnetic resonance imaging (MRI) systems, positron emission tomography (PET) imaging systems, single photon emission computed tomography (SPECT) imaging systems, ultrasound imaging systems, and combinations thereof (e.g., multi-modality imaging systems such as PET / CT, PET / MR, or SPECT / CT imaging systems). Discussion herein of a CT imaging system is provided merely as one example of one suitable imaging system.

[0017] FIG. 1 illustrates an exemplary CT imaging system 100 configured for CT imaging. Specifically, the CT imaging system 100 is configured to image a subject 112, such as a patient, an inanimate object, one or more manufactured parts, and / or a foreign object present in a body, such as a dental implant, a stent, and / or a contrast agent. In one embodiment, the CT imaging system 100 includes a gantry 108, which in turn may further include at least one X-ray source 104 configured to project an X-ray radiation beam 106 (see FIG. 2). Specifically, the X-ray source 104 is configured to project the X-ray radiation beam 106 toward a detector array 108 disposed on the opposite side of the gantry 108. Although FIG. 1 illustrates only a single X-ray source 104, in some embodiments multiple X-ray sources and detectors may be used to project multiple X-ray radiation beams 106 to obtain projection data at various energy levels corresponding to the patient. In some embodiments, the X-ray source 104 may enable dual energy gemstone spectral imaging (GSI) with rapid peak kilovoltage (kVp) switching. In some embodiments, the X-ray detector used is a photon counting detector capable of discriminating between X-ray photons of different energies. In other embodiments, two sets of X-ray sources and detectors are used, one set at low kVp and the other at high kVp, to create dual energy projections. Thus, it should be appreciated that the methods described herein may be embodied with single energy and dual energy acquisition techniques.

[0018] In some embodiments, the CT imaging system 100 further includes an image processor unit 110 configured to reconstruct an image of the target volume of the subject using an iterative or analytical image reconstruction method. For example, the image processor unit 110 may reconstruct an image of the target volume of the patient using an analytical image reconstruction approach such as filtered back projection (FBP). As another example, the image processor 110 may reconstruct an image of the target volume of the subject 112 using an iterative image reconstruction approach such as advanced statistical iterative reconstruction (ASIR), conjugate gradient (CG), maximum likelihood expectation maximization (MLEM), model-based iterative reconstruction (MBIR), and the like. As described in more detail herein, in some examples, the image processor unit 110 may use both an analytical image reconstruction approach such as FBP in addition to an iterative image reconstruction approach.

[0019] In some CT imaging system configurations, an x-ray source projects a cone-shaped beam of x-ray radiation that is collimated to lie within an XYZ plane of a Cartesian coordinate system, commonly referred to as the "imaging plane." The x-ray radiation beam passes through an imaging object, such as a patient or subject. After being attenuated by the object, the x-ray radiation beam impinges on an array of detector elements. The intensity of the attenuated x-ray radiation beam received by the detector array depends on the attenuation of the x-ray radiation beam by the object. Each detector element of the array generates a separate electrical signal that is a measurement of the x-ray radiation beam attenuation at the detector location. Separate attenuation measurements from all detector elements are acquired to generate a transmission profile.

[0020] In some medical imaging systems, the x-ray source and detector array are rotated with a gantry in the imaging plane around the imaged object so that the angle at which the x-ray radiation beam intersects the object is constantly changing. A set of x-ray radiation attenuation measurements, e.g., projection data, from the detector array at one gantry angle is called a "view." A "scan" of the object includes a set of views made at different gantry angles, or view angles, during one revolution of the x-ray source and detector.

[0021] The projection data is processed to reconstruct an image corresponding to a two-dimensional slice through the object, or in some instances where the projection data includes multiple views or scans, a three-dimensional representation of the object. One method for reconstructing an image from a set of projection data is referred to in the art as the filtered backprojection technique. Transmission and emission tomography reconstruction techniques also include statistical iterative methods such as maximum likelihood expectation maximization (MLEM) and ordered subsets expectation reconstruction techniques, in addition to iterative reconstruction techniques. This process converts the attenuation measurements from the scan into integers called "CT numbers" or "Hounsfield units" and uses these values ​​to control the brightness of corresponding pixels on a display device.

[0022] To reduce the total scan time, a "helical" scan can also be performed. To perform a "helical" scan, the patient is moved while data for a given number of slices is acquired. Such systems generate a single helix from a cone beam helical scan. The helix imaged by the cone beam produces projection data from which images in each given slice can be reconstructed.

[0023] The phrase "reconstructing an image" as used herein is not intended to exclude embodiments of the invention in which data representative of an image is generated but no visible image is formed. Thus, as used herein, the term "image" refers broadly to both a visible image and data representative of a visible image. However, many embodiments form (or are configured to form) at least one visible image.

[0024] The CT imaging system 100 may receive power from a main power source 122 or an uninterruptible power supply (UPS) 124 through a power distribution unit (PDU) 120. Additionally or alternatively, the CT imaging system may receive power from a generator, in which case power from the generator may be provided through a similar coupling as the main power source 122. In one example, the PDU 120 may include one or more sensors configured to sense the availability of power from the main power source 122. A PDU controller 130 may be configured to receive feedback from the sensors and adjust the position of one or more actuators in response to the availability of power from the main power source 122 and a command signal from a gantry control board (GCB) of the CT imaging system 102. The one or more actuators may be adjusted after a predetermined time delay is measured by a timer. In one example, the one or more actuators are contactors and / or switches and are configured to alternate between the main power source 122 and the UPS 124 based on the availability of power from the main power source 122. In one example, if power from the mains becomes unavailable, the PDU controller 130 can signal a first switch to open the circuit in which the mains power source 122 is located and a second switch to close the circuit in which the UPS 124 is located, such that power is provided to the CT imaging system from the UPS 124, as will be described in more detail below.

[0025] The PDU controller 130 may include instructions stored in its memory that, when executed, cause the PDU controller 130 to adjust a switch or contactor that controls the power received from the mains power source 122 when power from the mains power source becomes unavailable. Power from the mains power source 122 may be sensed via a current sensor. Feedback from the current sensor instructs the PDU controller 130 to simultaneously activate a switch from the mains power source 122 and (after a time delay) activate a UPS switch from the UPS to the output load of the PDU 120 to power the CT imaging system 100.

[0026] FIG. 2 illustrates an exemplary imaging system 200 similar to the CT system 100 of FIG. 1. In accordance with an aspect of the present disclosure, the imaging system 200 is configured to image an object 204. In one embodiment, the imaging system 200 includes a detector array 108 (see FIG. 1). The detector array 108 further includes a plurality of detector elements 202 that collectively sense an x-ray radiation beam 106 (see FIG. 2) passing through an object 204 (such as a patient) to acquire corresponding projection data. Thus, in one embodiment, the detector array 108 is fabricated in a multi-slice configuration that includes multiple rows of cells or detector elements 202. In such a configuration, one or more additional rows of detector elements 202 are arranged in a parallel configuration to acquire projection data.

[0027] In some embodiments, the imaging system 200 is configured to traverse various angular positions about the object 204 to acquire the desired projection data. Thus, the gantry 102 and the components mounted to the gantry 102 may be configured to rotate about a center of rotation 206 to acquire projection data at various energy levels, for example. Alternatively, in embodiments in which the projection angle relative to the object 204 changes as a function of time, the mounted components may be configured to move along a general curve rather than along a circular arc.

[0028] As the x-ray source 104 and detector array 108 rotate, the detector array 108 collects data of the attenuated beam of x-ray radiation. The data collected by the detector array 108 is pre-processed and calibrated to condition the data to represent the line integrals of the attenuation coefficient of the object 204 being scanned. The processed data are commonly referred to as projections.

[0029] In some examples, individual detectors or detector elements 202 of the detector array 108 may include photon-counting detectors that register individual photon interactions into one or more energy bins. It should be appreciated that the methods described herein may also be implemented with energy integrating detectors.

[0030] The acquired projection data set may be used for basis material decomposition (BMD). During BMD, the measured projections are converted into a set of material density projections. The material density projections may be reconstructed to form a pair or set of material density maps or images of each respective basis material, such as a bone map, a soft tissue map, and / or a contrast agent map. The density maps or images may then be related to form a volume rendering of the basis materials, e.g., bone, soft tissue, and / or contrast agent, in the imaged volume.

[0031] Once reconstructed, the basis material image formed by the imaging system 200 reveals internal features of the subject 204, represented as densities of the two basis materials. The density image may be displayed to show these features. Traditional approaches to the diagnosis of medical conditions, such as disease states, and more generally, medical events, have contemplated a hard copy or display of the density image for the radiologist or attending physician to identify salient features of interest. Such features may include lesions, the size and shape of particular anatomical structures or organs, and other features that may be identified in the image based on the skill and expertise of the individual physician.

[0032] In one embodiment, the imaging system 200 includes a control mechanism 208 that controls movement of components such as the rotation of the gantry 102 and the operation of the X-ray source 104. In some embodiments, the control mechanism includes a timer 209. In some embodiments, the control mechanism 208 further includes an X-ray controller 210 configured to provide power and timing signals to the X-ray source 104. Additionally, the control mechanism 208 includes a gantry motor controller 212 configured to control the rotational speed and / or position of the gantry 102 based on imaging requirements.

[0033] In some embodiments, the control mechanism 208 further includes a data acquisition system (DAS) 214 configured to sample analog data received from the detector elements 202 and convert the analog data to a digital signal for subsequent processing. As described further herein, the DAS 214 may be further configured to selectively aggregate analog data from a subset of the detector elements 202 as a so-called macro-detector. The data sampled and digitized by the DAS 214 is transmitted to a computer or computing device 216. In one example, the computing device 216 stores the data in a storage device or mass storage device 218. The storage device 218 may include, for example, a hard disk drive, a floppy disk drive, a compact disk read / write (CD-R / W) drive, a digital versatile disk (DVD) drive, a flash drive, and / or a solid-state storage drive.

[0034] Additionally, computing device 216 provides commands and parameters to one or more of DAS 214, x-ray controller 210, and gantry motor controller 212 for controlling system operations, such as data acquisition and / or data processing. In some embodiments, computing device 216 controls system operations based on operator input. Computing device 216 receives operator input, including, for example, commands and / or scanning parameters, via an operator console 220 operatively coupled to computing device 216. Operator console 220 may include a keyboard (not shown) or a touch screen that allows an operator to specify commands and / or scanning parameters.

[0035] 2 shows only one operator console 220, more than one operator console may be coupled to the imaging system 200, for example, for inputting and outputting system parameters, requesting examinations, plotting data, and / or viewing images. Additionally, in some embodiments, the imaging system 200 may be coupled to multiple displays, printers, workstations, and / or the like, which may be located locally or remotely, for example, within a facility or hospital, or in entirely different locations, and may be coupled via one or more configurable wired and / or wireless networks, such as the Internet and / or virtual private networks, wireless telephone networks, wireless local area networks, wired local area networks, wireless wide area networks, and wired wide area networks, etc.

[0036] In one embodiment, for example, imaging system 200 includes or is coupled to a picture archiving and communication system (PACS) 224. In an exemplary implementation, PACS 224 is further coupled to remote systems, such as a radiology information system or a hospital information system, and / or a local or external network (not shown), allowing operators at various locations to provide commands and parameters and access image data.

[0037] The computing device 216 uses operator supplied and / or system defined commands and parameters to operate the table motor controller 226, which in turn can control the table 114, which can be a motorized table. Specifically, the table motor controller 226 can move the table 114 to properly position the subject 204 in the gantry 102 for acquiring projection data corresponding to a target volume of the subject 204.

[0038] As previously mentioned, the DAS 214 samples and digitizes the projection data acquired by the detector elements 202. The image reconstructor 230 then performs high speed reconstruction using the sampled and digitized x-ray data. Although FIG. 2 illustrates the image reconstructor 230 as a separate entity, in some embodiments, the image reconstructor 230 may form part of the computing device 216. Alternatively, the image reconstructor 230 may not be present in the imaging system 200, and instead the computing device 216 may perform one or more functions of the image reconstructor 230. Also, the image reconstructor 230 may be located either locally or remotely, and may be operatively connected to the imaging system 200 using a wired or wireless network. In particular, an example embodiment may utilize the computational resources of a "cloud" network cluster for the image reconstructor 230.

[0039] In one embodiment, the image reconstructor 230 stores the reconstructed image in the storage device 218. Alternatively, the image reconstructor 230 may transmit the reconstructed image to the computing device 216 for generating patient information useful for diagnosis and evaluation. In some embodiments, the computing device 216 may transmit the reconstructed image and / or the patient information to a display or display device 232 in communication with the computing device 216 and / or the image reconstructor 230. In some embodiments, the reconstructed image may be transmitted from the computing device 216 or the image reconstructor 230 to the storage device 218 for short-term or long-term storage.

[0040] In one embodiment, the display 232 allows the operator to evaluate the imaged anatomical structures. The display 232 may also allow the operator to select a volume of interest (VOI) for subsequent scanning or processing, for example via a graphic user interface (GUI), and / or request patient information.

[0041] In one example, the UPS 124 of FIG. 1 may be an existing UPS of the computing device 216 and its auxiliary components (e.g., the display 232 and the operator console 220, etc.). As described herein, the inventors have discovered a way to modify one or more circuits of the PDU 120 and the UPS 124 of FIG. 1 such that the UPS 124, which is pre-configured to power only the computing device 216, also powers the gantry 108 when power from the main power source 122 becomes unavailable. When the main power becomes available, the UPS can be charged via the main power source. As such, desired cooling of the gantry 108 can be performed in response to the unavailability of power from the main power source 122.

[0042] 3(A) through 4(B), an embodiment of a power interface between the UPS device 124 and the PDU 120 of the main power source 122 is shown. As such, the aforementioned components may be similarly numbered in these figures. The power distribution unit 120 may include the main power source 122 and a circuit having a circuit breaker 302, a three-phase input 304 for power, and a transformer 305. The transformer 305 may have a primary winding integrated with the three-phase input, a first secondary winding 310, and a second secondary winding 330. The power distribution unit 120 may include a number of electrical lines 308 that extend through corresponding switches of the three-phase input 304 to the primary winding of the transformer 305. The circuit breaker 302 may be configured to trip in response to a current of 150A (amperes) or greater flowing through any of the number of electrical lines 308.

[0043] The primary winding of the transformer 305 includes an electrical winding configured to draw power from a number of electrical lines or wires, which may be electrically coupled to the first secondary winding 310 and the second secondary winding 330 windings.

[0044] The first secondary winding 310 may include a higher voltage than the second secondary winding 330 and may transmit power via a plurality of wires 312 to a rectifier 316. In some examples, the plurality of wires or lines 312 may each include a fuse configured to interrupt a circuit in response to a current flowing through the plurality of wires or lines exceeding a rating of the fuse. A plurality of contacts (e.g., KXG contacts 315, KSS contacts 314) may be disposed between the first secondary winding 310 and the rectifier 316. The rectifier 316 may be a passive or active rectifier and is configured to convert alternating current (AC) to direct current (DC). The DC line or line is coupled to an output HVDC load 320, which may be used to power a gantry (e.g., the gantry 108 of FIG. 1). In one example, the power delivered to the output HVDC loads 320 is at a relatively high voltage (eg, greater than 600 VDC).

[0045] The second secondary winding 330 can deliver power through a number of lines or wires 332, through the UPS 124, to an output AC load 340. Each of the number of lines or wires 332 can include a fuse that is rated to interrupt the circuit in response to a current exceeding the fuse rating. In one example, the fuse is rated at 50A. However, the fuse may be rated at other amperages based on the size and ampere rating of the number of wires. The output AC load 340 can deliver power to downstream power consumers, such as consoles, power cabinets, computers, etc.

[0046] Figure 3(A) shows a schematic diagram of PDU 120, which includes a three-phase main transformer 305, an autotransformer 306, two AC-DC converters 316 and 317, and several three-phase contactors KSS 314, KXG 315, KBK 350a, and KDC 355. Figure 3(B) shows the control circuitry associated with the schematic diagram of Figure 3(A). The control circuit shown in Fig. 3(B) includes several three-phase contactors KJC 342, 342a, 342b, KBK 350, 350a, KDC 355, 350a, several timers DR 357, 357a, TR 356, 356a, several relays R1 344, 344a, 344b (common contact 11 connected to contact 14), 344c (common contact 11 connected to contact 12), and R2 354, 354a. The main transformer 305 has three windings, the primary winding 304 is delta connected and connected to the main utility power supply 122 by the main circuit breaker (CB1) 302. The first and second secondary windings 310, 330 are wye (star) connected. The first secondary winding 310 supplies high voltage direct current (HVDC) power to a terminal block (TS2) 320. The second secondary winding 330 provides low voltage alternating current (LVAC) power to terminal block (TS5) 340. All of the components shown in Figures 3A and 3B are located inside the PDU 120 except for the UPS 124. The UPS 124 may be optional and may be used as a backup power for the PDU 120. The input power of the UPS 124 is connected to a terminal block 346 of the PDU 120 and the output power of the UPS 124 is connected to a terminal block 347 of the PDU 120. If a UPS is not available as a backup power, then the terminal block 346 must be connected directly to the terminal block 347.

[0047] In FIG. 3B, the control circuit receives power from output phase B of UPS 124 via a 24V supply line. In addition, input phase B of UPS 124 supplies 120V to the control circuit in a single phase (e.g., phase B) that is used to power the control circuit since only one phase is needed to enable the control circuit to determine if a power outage has occurred and trigger a response to the power outage. Specifically, the KJC contact 342 is the trigger for the response to the power outage since it acts to detect a loss of power from UPS 124 via phase B. Power may alternatively come from either phase A or phase C. The control circuit is also connected to the Gantry Control Board (GCB) via terminals 6 and 7.

[0048] Figures 3(A) to 4(B) show a schematic diagram of the sequence of operation of the power circuit under normal operating conditions. Figures 3(A) and 4(A) both show the power circuit, and Figures 3(B) and 4(B) show the control circuit. Figures 3(A) and 3(B) show the first stage of operation (e.g., receiving power from the power source) under normal operating conditions. Under normal operating conditions, the normally closed (NC) KJC contact 342a and the R1 contacts 344a, 344c are closed in the initial starting stage. When power is supplied from the power source 122 to the PDU and transferred to the second secondary winding 330, the power is passed to the terminal block 346 of the PDU 120, and the normally open (NO) KJC auxiliary contact 342b closes at the same time that the NC of the KJC contact 342a opens, as shown in Figures 4(A) and 4(B). The KJC contact 342 is a contact that acts to detect whether the main power source is available. When the main power source 122 is available, the KJC contacts or switches 342, 342a, 342b are in a first position (e.g., KJC contact 342a NC open and KJC auxiliary contact 342b NO closed) enabling a normal operating condition. When the main power source 122 is not available, such as before the system is powered on or during a power failure condition, the KJC contacts or switches 342 are in a second position (e.g., KJC contact 342a NC closed and KJC auxiliary contact 342b NO open). During normal operating conditions, power flows through the UPS 124 via terminal block 346 of the PDU 120, from the UPS back to terminal block 347 of the PDU 120, and to the PDU TS5, which is the AC power output or load 340. Additionally, power flows from the UPS 124 to the KBK contact 350a, which is disconnected during normal operating conditions. As shown in Figures 4(A) and 4(B), the Gantry Control Board (GCB) sends a signal (e.g., SYS_XG_CONT signal 352) to the PDU 120. The XG_CONT signal 353 provides signal power to each contact to keep the contacts (e.g., KSS contact 314, and after a short delay, KXG contact 315) in a closed position when the contacts are normally open. The R1 contact 344 then switches, the R2 contact 354a closes, and the KSS contact 314 closes as shown in Figure 4(A). After a short delay (e.g., 1.2 seconds), the KXG contact 315 closes as shown in Figure 4(A).4(A), HVDC power is then applied through rectifier 316 to terminal block TS2 320 and normal operation of the CT imaging system resumes, and the system is ready to perform a scan.

[0049] Upon detection of power loss, the system enters power loss mode or power loss operation. Figures 5(A) to 8(B) are schematic diagrams showing the sequence of operations of the power and control circuits during power loss mode. Power loss mode begins in Figure 5(A) with the detection of loss of power from the primary power source 122. Figure 5(B) shows the control circuit at this initial stage of power loss mode. At this initial stage, the Aux contact of CB1 1002 is closed. After a short period of power loss, when power is not being supplied to the UPS 124, the KJC coil 342 is deactivated. The auxiliary contacts 342a and 342b close and open, respectively, interrupting the XG_CONT signal 353 to the KSS contact 314 and the KXG contact 315 as shown in Figure 5(A). In addition, the R1 contact 344 switches (i.e., 344b switches to 344c). As shown in Figure 5(B), the control circuitry closes KJC contact 342a and R1 contact 344a. Figure 5(A) shows that KSS contact 315 and KXG contact 314 open as a result of interruption of SYS_XG_CONT signal 352, thereby also preventing power transfer to HVDC load 320. As shown in Figure 5(B), SYS_XG_CONT signal 352 is no longer transferred from the GCB. In addition, as shown in Figure 5(B), the control circuitry opens R2 354a contact.

[0050] In Figure 6(A), UPS battery power is passed to PDU TS5 347 or AC load 340, thus powering the gantry and associated control circuitry as shown in Figures 6(A) and 6(B). Figures 7(A) and 7(B) show the power and control circuitry when DR timer 357 is activated. DR timer 357 is a delay circuit that is enabled to determine whether the power loss detected by KJC contact switch 344a is a momentary power loss (e.g., power flicker or surge) or a significant power loss (e.g., a power loss that lasts longer than a threshold amount of time). DR timer 357 enables a delay of a threshold amount of time or duration, which in some examples is 9 seconds. After the delay, DR contact 357a changes state. After a certain time delay (e.g., 12.5 seconds after primary power is lost), the SYS_XG_CONT signal 352 from the GCB resumes, resulting in the R2 relay 354 activating, closing the R2 NO contact 354a, and activating the KBK contact 350 and timer TR 356, which immediately closes the KBK contact 350a, enabling the autotransformer 306 to step up the voltage, then rectify the voltage, enabling power to be provided from the UPS 124 to the DC load 320, as shown in Figures 8(A) and 8(B). In the illustrated example, the UPS 124 is sufficient to provide HVDC power to the DC load 320 for a period long enough to cool the tubes. In other applications, the UPS 124 may be adjusted to provide a different amount of power. Additionally, the KSS contacts 315 and the KXG contacts 314 are closed by sending a 24V signal through the KBK contacts 350a and relay R1 344c as the XG_CONT 353 signal. After a one second delay, the TR contacts 356a change state, closing the KDC contacts 355a and enabling power transfer from the UPS 124 to the rectifier 317 and the DC loads 320 to provide backup HVDC power to the CT imaging system. In some examples, the UPS 124 can provide backup HVDC power until power is restored from the power source 122. Alternatively, the UPS 124 can provide power for a predetermined period of time (e.g., 45 minutes) to allow the CT imaging system to properly cool down and safely shut down.

[0051] 9-10(B) show a schematic diagram of the sequence of operations of the power and control circuits during a power restoration condition. FIG. 9 shows the initial restoration of power from the power source. Upon restoration of power, as shown in FIG. 9, LVAC power is provided through the primary power source 122, not through the UPS 124. For a few milliseconds, the DC load 320 has two sources of power. One is from the power source 122 through the secondary winding 305, the KSS 314 and KXG 315 contactors, and the rectifier 316. The second source is from the UPS 124 through the KBK 350a contactor, the autotransformer 306, and the rectifier 317. By having two sources of power available, the CT system 102 and the computing device 216 do not suffer any brownouts or voltage drops. The backup power switches to the primary power source without resetting or rebooting the CT system. Additionally or alternatively, in some examples, a capacitor 351 is placed in the control circuit between the R1 contact 344a and the XG_CONT signal 353. This capacitor holds enough charge to overcome minor power disruptions, such as switching from the UPS 124 back to the primary power source 122. By overcoming these minor power disruptions, the capacitor 351 can eliminate the need to restart the CT system 102, allowing the CT system 102 to recover to scanning mode more quickly. In addition, a normal SYS_XG_CONT signal 352 is provided from the GCB. The KBK 350a and KDC 355a contacts open, preventing power from the UPS 124 to the HVDC output 320 and changing the standby HVDC state. Contacts KJC Aux 342b and R1 344a close, enabling the SYS_XG_CONT signal 352 to reach KSS contacts 315 and KXG contacts 314, as shown in Figures 10(A) and 10(B). KSS contacts 314 close and after a 1.2 second delay KXG contacts 315 close. Normal operation resumes and the CT imaging system is ready for operation.

[0052] 11 illustrates a method 1100 for adjusting an energy source based on the availability of electrical energy from a main power source 122. Instructions for the method may be executed and stored by a memory of a controller of the PDU (e.g., PDU controller 130 of FIG. 1). The controller may be configured to receive input from one or more sensors of the PDU 120 and adjust the operation of one or more switches to change the direction of current flow.

[0053] The method 1100 begins at block 1102, which includes turning on the CT imaging system power. Turning on the system power may include, for example, operating a switch and / or a plug. After the system power is turned on, the CT imaging system proceeds to initiate normal operating conditions and prepares to perform a scan. In some examples, immediately after turning on the system power, AC power is available to the AC loads via the AC power output of the PDU, as shown in Figures 3(A) and 3(B). The method continues at step 1104, where the GCB sends a SYS_XG_CONT signal to the PDU after closing the KJC contacts to initiate the start-up process for the normal operating conditions (block 1106). Initiating the normal operating conditions may include closing the R2, R1, and KSS contacts, as shown in Figures 4(A) and 4(B). In addition, after a delay, the KXG connector closes to provide HVDC power to the gantry. The system is now in normal operating conditions and is ready to perform a scan (block 1108). Under normal operating conditions, the UPS can be charged.

[0054] In block 1110, the system (e.g., gantry control board, PDU controller, etc.) operates to detect a power outage. If no power outage is detected, the system continues to operate under normal conditions. If a power outage is detected, the system initiates a power loss operating condition (block 1112). First, the KJC auxiliary contact opens to interrupt the SYS_XG_CONT signal (FIG. 5(A)). This opens the KSS and KXG contacts to disable the HVDC output from the PDU (FIG. 5(A)). At the same time, UPS power is provided as an AC output from the PDU. The delay relay is enabled. In block 1114, the system determines if the power outage has lasted for a time period that exceeds a threshold (e.g., using a time-delay relay). If the power outage has not exceeded the threshold amount of time, the system determines that the power outage is a temporary surge or flicker and restores to normal operating conditions. If the power outage duration exceeds the threshold, the delay relay contact DR closes and the system subsequently enters a power loss mode operating condition (block 1116). To continue in power loss mode, the system resends the SYS_XG_CONT signal via the GCB, which now uses the UPS to provide power. The SYS_XG_CONT signal closes the KSS contacts, then the KXG contacts, and simultaneously closes the KBK contacts, activating the time relay. Closing the KBK relay results in transformer operation (Figures 8(A) and 8(B)). The time relay delays the closure of the KDC contacts by 1 second, and then closes the KDC contacts, allowing HVDC power to be provided from the UPS to the DC outputs of the PDU.

[0055] The method continues at block 1118 by waiting for the imaging system tubes to cool down. In some examples, the system waits a predetermined amount of time (e.g., 45 minutes) for the tubes to completely cool down. In other examples, a sensor may be used to determine when the tubes have completely cooled down. Once the tubes have cooled down, the method continues at block 1120 by determining if the primary power source has returned. If the primary power source has returned, the system begins to recover to normal operating conditions (block 1122). Recovery to normal operating conditions begins with LVAC power being provided through the primary power source instead of the UPS as shown in FIG. 9. In addition, a normal SYS_XG_CONT signal is provided from the GCB. The KBK and KDC contacts open, preventing power from the UPS to the HVDC output and changing the standby HVDC state. The KJC Aux and R1 contacts close to allow the SYS_XG_CONT signal to reach the KSS and KXG contacts as shown in FIG. 10(A) and FIG. 10(B). After the KSS contacts close, the KXG contacts close after a 1.2 second delay, allowing normal delivery of HVDC power through the primary source as shown in Figures 10(A) and 10(B). The system is again ready to scan and the method is complete.

[0056] If primary power has not returned at block 1120, then tube cooling is terminated (block 1124), the system is shut down, and the method is complete.

[0057] As used herein, terms such as "a," "an," "an," or "b," referring to an element or step in the singular, should be understood as not excluding a plurality of such elements or steps, unless the exclusion is expressly stated. Moreover, references to "one embodiment" of an invention do not exclude the existence of additional embodiments that also incorporate the recited features. Moreover, unless expressly stated to the contrary, embodiments that "comprise," "include," or "have" an element or elements having a particular characteristic may also include additional elements that do not have that characteristic. Additionally, the term "including" is used as the standard English equivalent of "comprising," and the term "in which" is used as the standard English equivalent of "wherein." Furthermore, terms such as "first," "second," and "third" are used merely as labels, and do not impose numerical requirements or a particular positional order on the objects of these terms.

[0058] The control methods and control routines disclosed herein can be stored as executable instructions in a non-transient memory and executed by a control system including a controller in combination with various sensors, actuators, and other engine hardware. The particular routines described herein can represent one or more of any number of processing strategies, such as event-driven operation, interrupt-driven operation, multi-tasking operation, multi-threaded operation, and the like. As such, the various operations, acts, and / or actions depicted may be performed in the order depicted, in parallel, or in some cases omitted. Similarly, the order of operations is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is presented for ease of illustration and description. One or more of the illustrated operations, acts, and / or actions may be performed repeatedly depending on the particular strategy being used. Additionally, the described operations, acts, and / or actions can be illustrated as code programmed and embedded in a non-transient memory of a computer-readable storage medium of an engine control system, where the described operations are performed by executing instructions of a system including various engine hardware components in combination with an electronic controller.

[0059] This written description uses examples to disclose the invention, including the best mode, and to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are considered to be within the scope of the claims if they have structural elements that do not differ from the written language of the claims, or if they include equivalent structural elements that have insubstantial differences from the written language of the claims. [Explanation of symbols]

[0060] 100 CT Imaging System 102 Gantry 104 X-ray source 106 X-ray radiation beam 108 Detector Array 114 Table 200 Imaging System 202 Detector element 204 Subject 206 Rotation Center 208 Control Mechanism 209 Timer 232 Display 302 Main circuit breaker (CB1) 304 Three-phase input (primary winding) 305 Transformer 306 Autotransformer 308 Power Lines 310 First secondary winding 312 Electric wire 330 Secondary Winding 332 Electric lines or cables 342, 342a, 342b three phase contactor KJC 344, 344a, 344b, 344c Relay R1 346 Terminal Block (Input to UPS) 347 Terminal block (output from UPS) 350, 350a three phase contactor KBK 351 Capacitor 352 SYS_XG_CONT signal 353 XG_CONT signal 354, 354a Relay R2 355, 355a three phase contactor KDC 356, 356a Timer TR 357, 357a Timer DR 1002 CB1 Aux Contact 1100 Method for adjusting an energy source based on the availability of electrical energy from a main power source

Claims

1. 1. A system comprising: a power distribution unit (PDU) configured to receive power from a mains power source and an uninterruptible power supply (UPS) configured to directly power output alternating current (AC) loads after the mains power source becomes unavailable, the UPS further configured to power output high voltage direct current (HVDC) loads via a pass-through current through an autotransformer and an AC-DC converter that steps up the voltage.

2. 2. The system of claim 1, further comprising a first contact switch for detecting availability of primary power, wherein when primary power is available, the first contact switch is in a first position that activates a signal that enables a normal operating condition, and when primary power is not available, the first contact switch is in a second position that enables a power loss mode operating condition.

3. 3. The system of claim 2, further comprising a delay circuit enabled to determine whether the power loss detected by the first contact switch is a momentary power loss or a significant power loss.

4. 4. The system of claim 3, wherein the delay circuit includes a timer that closes a delay contact after a threshold period of time.

5. 5. The system of claim 4, further comprising a second contact that closes after the delay contact closes if the power loss exceeds a threshold period, the closing of the second contact enabling the UPS to supply power to the autotransformer.

6. The system of claim 1 , wherein the output AC load supplies AC power to a plurality of systems of a computed tomography (CT) imaging system.

7. 10. The system of claim 1, wherein the output HVDC load supplies HVDC power to a plurality of systems within a gantry of a computed tomography (CT) imaging system.

8. 2. The system of claim 1, wherein the UPS is configured to power the output AC loads and the output HVDC loads in response to power becoming unavailable from the mains power source.

9. 10. The system of claim 1, further comprising a capacitor that holds a sufficient charge to overcome a power interruption and eliminate the need to restart the system.

10. a gantry coupled to an output HVDC load; a power supply cabinet coupled to an output AC load; a power distribution unit (PDU) configured to receive power from one of a mains power source and an uninterruptible power supply (UPS), the UPS providing power to the HVDC loads via an autotransformer when the mains power source becomes unavailable; a plurality of contactors coupled to the PDU and the UPS, and a timer; a controller having computer readable instructions stored in a memory for controlling the plurality of contactors based on the availability of the main power source and input from the timer; A computed tomography (CT) imaging system comprising:

11. 11. The CT imaging system of claim 10, wherein the plurality of contactors includes a first contact switch for detecting availability of main power, and when main power is available, the first contact switch is in a first position that activates a signal that activates a normal operating condition, and when main power is not available, the first contact switch is in a second position that activates a power loss mode operating condition.

12. 12. The CT imaging system of claim 11, further comprising a delay circuit enabled to determine whether the power loss detected by the first contact switch is a momentary power loss or a significant power loss.

13. 13. The CT imaging system of claim 12, wherein the delay circuit includes a timer that closes a delay contact after a threshold period of time.

14. 14. The CT imaging system of claim 13, wherein the plurality of contactors further includes a second contact that closes after the delay contact closes if the power loss exceeds a threshold time period, and closing the second contact enables the UPS to supply power to the autotransformer.

15. 11. The computed tomography (CT) imaging system of claim 10, wherein the output AC load supplies AC power to a plurality of systems of the CT imaging system.

16. 11. The computed tomography (CT) imaging system of claim 10, wherein the output HVDC load supplies HVDC power to a plurality of systems within a gantry of the CT imaging system.

17. 11. The CT imaging system of claim 10, further comprising a capacitor that holds a sufficient charge to overcome a power interruption and eliminate the need to restart the CT imaging system.

18. 1. A method for a computed tomography (CT) imaging system executed via instructions stored in a memory of a controller, comprising: In response to mains power becoming unavailable, Powering the output AC load directly through an uninterruptible power supply (UPS); Wait for the time delay powering an output HVDC load via power coupled from the UPS via an autotransformer that steps up the voltage output from the UPS; in response to the main power source becoming available; Waiting until the tube of the CT imaging system has cooled; powering the output HVDC loads via the mains power supply; The method according to claim 1,

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