Control device and method for high voltage generator

Abstract

The embodiment of the invention provides a control device and method for a high voltage generator. The method comprises the following steps: when it is detected that a high voltage generator needs to switch a current output state to a target output state, obtaining a current output voltage and a target output voltage of the high voltage generator; determining an outer loop control quantity according to the current output voltage and the target output voltage; obtaining a physical quantity corresponding to an internal circuit module of the high-voltage generator; according to the physical quantity and the outer ring control quantity, determining an inner ring control quantity corresponding to the internal circuit module, the value range of the inner ring control quantity being dynamically determined according to the physical quantity and / or the target output state; and determining a closed-loop control quantity of the high-voltage generator based on the inner-loop control quantity so as to control the high-voltage generator.

Description

Technical Field

[0001] The present specification relates to the field of control technology, and in particular to a control device and method for a high voltage generator. Background Art

[0002] In the high-voltage generator of the X-ray tube, the output of the high-voltage generator needs to meet the normal working conditions of the system (for example, reach the specified voltage value and / or the specified current value), and also needs to quickly transition the current output state to another output state under some special circumstances, for example, the output voltage needs to be quickly restored after the tube is ignited, the output voltage needs to be quickly switched, etc. Generally speaking, the shorter the transition time from the current output state to another output state, the more beneficial it is to the system performance.

[0003] Therefore, it is desirable to provide a control device and method for a high voltage generator to shorten the state switching time of the high voltage generator. Summary of the invention

[0004] In one aspect, the present specification provides a control method for a high-voltage generator. The method includes: when it is detected that the high-voltage generator is to switch from a current output state to a target output state, obtaining the current output voltage and the target output voltage of the high-voltage generator; determining an outer loop control quantity according to the current output voltage and the target output voltage; obtaining the corresponding physical quantity of the internal circuit module of the high-voltage generator; determining the inner loop control quantity corresponding to the internal circuit module according to the physical quantity and the outer loop control quantity; the value range of the inner loop control quantity is dynamically determined according to the physical quantity and / or the target output state; and determining the closed-loop control quantity of the high-voltage generator based on the inner loop control quantity to control the high-voltage generator.

[0005] In some embodiments, the high voltage generator includes a multi-stage inner loop control circuit, which is used to sample the corresponding physical quantity of the internal circuit module coupled thereto, and a plurality of the inner loop control circuits are connected in series in sequence to form the multi-stage inner loop control circuit.

[0006] In some embodiments, the high voltage generator includes a plurality of internal circuit modules, and the plurality of internal circuit modules are coupled and connected with the multi-stage inner loop control circuit in a one-to-one correspondence.

[0007] In some embodiments, the high-voltage generator includes multiple internal circuit modules, and the multi-stage inner-loop control circuit includes at least one stage of inner-loop control circuit coupled to two or more internal circuit modules, and the at least one stage of inner-loop control circuit is used to sample corresponding physical quantities of the two or more internal circuit modules.

[0008] In some embodiments, the internal circuit module includes an inverter circuit, a resonant network, a transformer circuit and a rectifier filter circuit connected in sequence, and the physical quantity includes at least one of the following: an inverter current, a voltage difference between the bridge arms of the inverter circuit, a voltage of the series resonant capacitor of the resonant network, and a primary voltage of the transformer circuit.

[0009] In some embodiments, determining the inner loop control quantity corresponding to the internal circuit module based on the physical quantity and the outer loop control quantity includes: determining the value range of the inner loop control quantity based on the physical quantity and / or the target output state; determining the inner loop set value based on the value range and the outer loop control quantity; determining the inner loop control quantity based on the inner loop set value and the physical quantity.

[0010] In some embodiments, the value range of the inner loop control quantity includes an upper limit and / or a lower limit of the value of the inner loop control quantity, and the upper limit or the lower limit is determined according to a value trajectory that changes with time.

[0011] In some embodiments, determining the value range includes: determining the corresponding inner loop control quantity of the internal circuit module by calculation or looking up a preset table based on the corresponding physical quantity of the internal circuit module and / or the target output state.

[0012] Another aspect of the present specification provides a control device for a high-voltage generator. The device includes: an outer loop control circuit, the input end of the outer loop control circuit is connected to the output end of the high-voltage generator, used to sample the current output voltage of the high-voltage generator, and determine the outer loop control amount according to the current output voltage and the target output voltage; an inner loop control circuit, one input of the inner loop control circuit is connected to the internal circuit module of the high-voltage generator, used to sample the corresponding physical quantity of the internal circuit module; another input is connected to the outer loop control circuit, used to determine the inner loop control amount corresponding to the internal circuit module according to the sampled physical quantity and the outer loop control amount; the value range of the inner loop control amount is dynamically determined according to the physical quantity or the target output state; wherein the control device is configured to determine the closed-loop control amount of the high-voltage generator based on the inner loop control amount to control the high-voltage generator.

[0013] In some embodiments, the device includes a multi-stage inner-loop control circuit, which is coupled to the internal circuit module and is used to sample the corresponding physical quantity of the internal circuit module; wherein a plurality of the inner-loop control circuits are connected in series in sequence to form the multi-stage inner-loop control circuit.

[0014] Another aspect of the present specification provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the control method of the high voltage generator as described above when executing the computer program.

[0015] Another aspect of the present specification provides a computer-readable storage medium, wherein the storage medium stores computer instructions. When a computer reads the computer instructions in the storage medium, the computer executes the control method of the high voltage generator as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] This specification will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0017] Figure 1 is a schematic diagram of an application scenario of an exemplary high voltage generator control method according to some embodiments of this specification;

[0018] Figure 2 is a schematic structural diagram of an exemplary high voltage generator according to some embodiments of this specification;

[0019] Figure 3 is a schematic structural diagram of an exemplary control device for a high voltage generator according to some embodiments of this specification;

[0020] Figure 4 is a schematic structural diagram of an exemplary high voltage generator and a control device thereof according to some embodiments of this specification;

[0021] Figure 5 is a schematic structural diagram of an exemplary inner loop control amount limiting module according to some embodiments of this specification;

[0022] Figure 6 is a schematic diagram of the structure of an exemplary inner loop control circuit according to some embodiments of this specification;

[0023] Figure 7 is a flowchart of an exemplary method for controlling a high voltage generator according to some embodiments of the present specification. DETAILED DESCRIPTION

[0024] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0025] It should be understood that the "system", "device", "unit" and / or "module" used herein are a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0026] As shown in this specification and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0027] Flowcharts are used in this specification to illustrate the operations performed by the system according to the embodiments of this specification, and the relevant description is to help better understand the control method and / or system. It should be understood that the previous or subsequent operations are not necessarily performed accurately in order. On the contrary, the steps can be processed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or one or more operations can be removed from these processes.

[0028] Figure 1 It is a schematic diagram of an application scenario of an exemplary high-voltage generator control method shown in some embodiments of this specification.

[0029] As the core component of X-ray system, high voltage generator is widely used in medical imaging detection, industrial non-destructive testing, security inspection industry and other occasions. Figure 1 is an example of a medical imaging test. X-ray technology can image the X-ray information passing through the scanned object (such as the target object). In some embodiments, the X-ray imaging equipment may include a computed tomography (CT) system, an X-ray photography (including the use of an image intensifier, an X-ray television or film device), a computer X-ray photography system (computed radiography, CR) and an X-ray digital imaging (Digital Radiography, DR) device, etc.

[0030] like Figure 1 As shown, in the X-ray imaging system, the ray source 110 is used to project an X-ray beam to a target object 130 lying flat (or prone) on a support plate 150. After the X-ray beam is limited by the collimator 120 for the irradiation range (for example, the shape and size of the X-ray beam), it passes through the target object 130 and enters the detector 140. The detector 140 generates a detector output signal by detecting the intensity of the X-ray beam passing through the target object 130. Based on the output signal, a medical image of the target object can be obtained through relevant processing.

[0031] like Figure 1 As shown in , during imaging, rays (e.g., X-rays) are emitted from the ray tube (i.e., the ray source), which has a cathode side (filament) and an anode side (target surface). The voltage applied between the cathode side and the anode side of the ray tube is called the tube voltage, which is used to form a high-voltage electric field so that the thermal electrons emitted by the filament can bombard the target surface at high speed under the acceleration of the high-voltage electric field, thereby exciting the rays. The high-voltage generator can be used to generate a stable high-frequency inverted DC high voltage (e.g., 140kv to 150kv) with sufficient power to supply the ray tube under the control of the computer program of the imaging system.

[0032] As an example, in a CT (Computed Tomography) imaging system, before high-voltage exposure, the CT main control computer issues instructions and provides the parameters and conditions required for exposure (e.g., KV, MA, KW). After receiving the instructions, the high-voltage generator performs a status detection, and after confirming that everything is normal, it sends a high-voltage ready information to the CT host. The CT host then issues an exposure command and transmits an exposure control pulse to the high-voltage generator. The high-voltage generator starts the rotating anode, excites the filament current, adjusts the primary voltage of the high-voltage generator to the CT specified parameter value (e.g., specified voltage), sends the high-voltage generator feedback information (e.g., the feedback information can be "confirmed" or "OK", etc.) and starts to generate high voltage to supply the tube (i.e., the CT system radiation source) for exposure. During the entire exposure period, the high-voltage primary voltage is constantly adjusted in time according to the change of current to ensure that the entire exposure process produces a stable pulse high voltage and a relatively constant tube current.

[0033] In addition to outputting normal working conditions that meet the system's needs (e.g., reaching a specified voltage value and / or current value), the high-voltage generator also needs to switch the current output state to another output state, such as quickly recovering to the output voltage after the X-ray tube ignites, quickly switching the output voltage, etc. In the process of state switching, the shorter the time spent, the more beneficial it is to the system's operating performance (e.g., imaging performance).

[0034] In some embodiments, the output voltage of the high-voltage generator can be sampled through a closed-loop control circuit, and a control signal (e.g., a closed-loop control quantity) can be generated by performing correlation operations between the sampled current output voltage and the target output voltage corresponding to the target output state. The output of the high-voltage generator is controlled based on the control signal so that the high-voltage generator reaches the target output voltage.

[0035] Figure 2 is a schematic structural diagram of an exemplary high voltage generator according to some embodiments of the present specification.

[0036] Figure 2 The main power part of the high voltage generator is shown in the dotted box. As shown in the figure, in some embodiments, the main power part of the high voltage generator (also called the internal circuit module) may include an inverter circuit, a resonant network, a transformer circuit, and a rectifier filter circuit connected in sequence. The output end of the high voltage generator is connected to a ray source (e.g., a tube), and the output voltage of the high voltage generator can act on the ray source (e.g., a tube).

[0037] Among them, the inverter circuit can also be called a fission circuit. For example, an inverter bridge circuit (such as a full-bridge or half-bridge circuit) composed of two or more switch tubes, or a switch tube and a capacitor, connected in series can be used to convert the input DC voltage into an AC voltage. In some embodiments, the inverter circuit may include but is not limited to a triode switch circuit, a field effect switch circuit (MOS switch circuit), a junction or insulated gate bipolar transistor (IGBT), a field effect transistor (FET) or a metal-oxide semiconductor field effect tube (MOS-FET).

[0038] The resonant network can be used to change the gain of the circuit and assist the fission part to work in a preset state according to the inverter circuit. In some embodiments, the resonant network can include a series resonant circuit or a series-parallel resonant circuit composed of an inductor and / or a capacitor.

[0039] The voltage conversion circuit is used to change the voltage, for example, it can be used for boosting, and includes capacitors and / or inductors, etc. In some embodiments, the voltage conversion circuit can be configured as a transformer with independent cathode and anode, or as a transformer with integrated cathode and anode.

[0040] The rectifier filter circuit is used for filtering, and the transformer circuit associated with the cathode of the ray tube and the transformer circuit associated with the anode can adopt the form of parallel connection of primary windings or the form of series connection of two primary windings.

[0041] In some embodiments, the high voltage generator 200 may further include a control device, which forms a closed-loop control loop with the inverter circuit and the output end of the high voltage generator (for example, the output of the rectifier filter circuit) to control the on or off of the switch device to adjust the duty cycle and / or the variable frequency. Different duty cycles (or switching ratios) or different frequencies correspond to different output voltages.

[0042] It should be noted that the above Figure 1 and Figure 2 The description is for illustrative purposes only and is not intended to limit the scope of this specification. For those of ordinary skill in the art, various variations and modifications may be made according to this specification. However, these variations and modifications do not depart from the scope of this specification. For example, the internal circuit structure of the high voltage generator 200 may include a first resonant branch and a second resonant branch, which are respectively connected to the first bridge arm and the second bridge arm of the inverter bridge circuit.

[0043] Figure 3 It is a schematic diagram of the structure of an exemplary control device for a high voltage generator according to some embodiments of the present specification.

[0044] The control device may include a single-loop control circuit and a dual-loop control circuit. A single-loop control circuit refers to a circuit that generates a control signal based only on the output voltage of the high-voltage generator. A dual-loop control circuit refers to a circuit that uses the output value of the outer-loop control circuit corresponding to the output voltage as the set value of the inner-loop control circuit to generate a control signal. The time it takes for the high-voltage generator to switch from the current output state to the target output state is related to the voltage and current stress of specific active and passive devices in the internal circuit structure of the high-voltage generator. The single-loop control circuit cannot automatically protect the voltage and current stress of the key points inside the high-voltage generator; the dual-loop control circuit composed of the voltage outer loop and the resonant current inner loop only limits the output of the outer loop control circuit, that is, the maximum value of the input of the inner loop control circuit, and it is difficult to achieve a good protection effect in the dynamic process.

[0045] A control device for a high-voltage generator is provided in an embodiment of the present specification, comprising a closed-loop control circuit composed of multiple levels (e.g., two levels or more) of control circuits, and dynamically limiting the upper and lower limits of the reference value (e.g., the inner loop control amount) of each level of the control circuit, so that the voltage and current stresses of key points inside the high-voltage generator are protected while fully utilizing the hardware capabilities, thereby shortening the switching time between different output states.

[0046] like Figure 3As shown, in some embodiments, the control device 300 may include an outer loop control circuit 310 and an inner loop control circuit 320. The input end of the outer loop control circuit 310 is connected to the output end of the high voltage generator for sampling the output voltage of the high voltage generator (for example, the current output voltage). The inner loop control circuit 320 is connected to the internal circuit module of the high voltage generator for sampling the corresponding physical quantity of the internal circuit module. In some embodiments, the control device 300 may include a multi-stage inner loop control circuit. In some embodiments, a plurality of (for example, M, where M is greater than or equal to 1) inner loop control circuits are sequentially connected in series to form a multi-stage inner loop control circuit, and the first-stage inner loop control circuit in the multi-stage inner loop control circuit is connected in series with the outer loop control circuit. Among them, the first-stage inner loop control circuit refers to the first of the multiple inner loop control circuits connected in series, for example, the 1-stage inner loop control circuit 320-1.

[0047] In some embodiments, the outer loop control circuit 310 may include two inputs, one of which is connected to the output end of the high voltage generator (e.g., the output of the rectifier filter circuit) to sample the current output voltage of the high voltage generator; the other input receives a voltage setting value. The voltage setting value of the outer loop control circuit is the output voltage corresponding to the target output state to which the radiographic imaging system needs to switch, referred to as the target output voltage. In some embodiments, Figure 4 As shown, the outer loop control circuit 310 may include modules such as signal processing, analog-to-digital conversion, and outer loop operation. The signal processing module may perform processing such as scaling, analog or digital filtering, lead or lag compensation, etc. on the sampled current output voltage. The analog-to-digital conversion module may convert the processed output voltage into a digital signal. The outer loop operation module may perform operations on the digital signal corresponding to the output voltage and the target output voltage, for example, a subtraction operation, to obtain the output value of the outer loop control circuit (hereinafter referred to as the outer loop output value), i.e., the outer loop control amount. In some embodiments, the outer loop output value may be used as a set value of the first-level inner loop control circuit (e.g., the first-level inner loop control circuit 320-1) in the multi-level inner loop control circuit.

[0048] The inner loop control circuit 320 may include a 1-level inner loop control circuit 320-1, a 2-level inner loop control circuit 320-2, ..., an M-level inner loop control circuit 320-m. In some embodiments, the multi-level inner loop control circuit may be used to sample one or more physical quantities corresponding to the internal circuit module connected thereto. In some embodiments, the physical quantity may include, but is not limited to, the corresponding inverter current of the internal circuit structure of the high voltage generator, the voltage of the series resonant capacitor, the voltage difference between the bridge arms of the inverter circuit, the primary voltage of the transformer circuit, the output current, etc., or any combination thereof. For example, the 1-level inner loop control circuit 320-1 is used to sample one or more physical quantities (e.g., the voltage and / or resonant current of the series resonant capacitor) of the internal circuit module (e.g., the resonant network) coupled thereto.

[0049] The inverter current refers to the input / output current of the midpoint of the bridge arm of the full-bridge circuit or half-bridge circuit composed of the inverter circuit. The midpoint of the bridge arm is not necessarily limited to the middle point in the physical scale, and it can be any point on the line between two switch tubes (for example, the first switch tube and the second switch tube connected in series). In some embodiments, when the high voltage generator is based on a resonant circuit topology, the inverter current can refer to the resonant current.

[0050] The voltage of the series resonant capacitor refers to the capacitor voltage of the series resonant circuit or series-parallel resonant circuit composed of inductance and / or capacitance in the high voltage generator, for example Figure 2 The capacitor voltage in the resonant network.

[0051] The voltage difference between the bridge arms of the inverter circuit may refer to the difference between the output voltages of the two groups of bridge arms of the full-bridge or half-bridge circuit composed of the switch tubes. For example, the full-bridge circuit includes a first bridge arm composed of a first switch tube and a second switch tube connected in series, and a second bridge arm composed of a third switch tube and a fourth switch tube connected in series, the first bridge arm and the second bridge arm are connected in parallel, and the voltage difference between the outputs of the bridge arms of the full-bridge circuit may be the voltage difference between the midpoint of the first bridge arm and the midpoint of the second bridge arm.

[0052] The primary voltage of the transformer circuit refers to the primary voltage of the step-up transformer. The output current of the high voltage generator can reflect its load status.

[0053] In some embodiments, the high voltage generator may include multiple internal circuit modules, and the multiple internal circuit modules are coupled and connected with the multi-level inner loop control circuit in a one-to-one correspondence. For example, the level 1 inner loop control circuit 320-1, the level 2 inner loop control circuit 320-2, the level 3 inner loop control circuit 320-3, and the level 4 inner loop control circuit 320-4 may be coupled and connected with the inverter circuit, the resonant network, the transformer circuit, and the rectifier filter circuit, respectively, and are used to sample the physical quantities corresponding to the inverter circuit, the resonant network, the transformer circuit, and the rectifier filter circuit, respectively.

[0054] In some embodiments, at least one of the multi-stage inner loop control circuits can be coupled to two or more internal circuit modules for sampling the corresponding physical quantities of the two or more internal circuit modules. For example, the first-stage inner loop control circuit 320-1 is coupled to the inverter circuit and the resonant network, and the second-stage inner loop control circuit 320-2 is coupled to the transformer circuit and the rectifier filter circuit. For another example, the first-stage inner loop control circuit 320-1 is coupled to the inverter circuit and the resonant network, the second-stage inner loop control circuit 320-2 is coupled to the transformer circuit, and the third-stage inner loop control circuit 320-3 is coupled to the rectifier filter circuit.

[0055] In some embodiments, the physical quantity corresponding to the internal circuit module may include an original physical quantity or a sampled value of the physical quantity. For example, the physical quantity corresponding to the resonant network may be a voltage value of a series resonant capacitor, such as 1000V, or a voltage value sampled by an inner loop control circuit coupled thereto, such as 800V.

[0056] In some embodiments, Figure 4 As shown, each inner loop control circuit may include modules such as signal processing, analog-to-digital conversion, and inner loop operation. Among them, signal processing may include but is not limited to scaling, analog or digital filtering, lead or lag compensation, etc. or any combination thereof. In some embodiments, the inner loop control circuit may include two inputs, one of which is connected to the internal circuit module of the high voltage generator for sampling the corresponding physical quantity of the internal circuit module; the other receives the output value of the previous control circuit (for example, the outer loop control quantity, the inner loop control quantity corresponding to the previous inner loop control circuit). In some embodiments, the inner loop control circuit can determine the inner loop control quantity corresponding to the current internal circuit module based on the sampled physical quantity and the outer loop control quantity (or the inner loop control quantity corresponding to the previous inner loop control circuit). The inner loop control quantity can be used to control the corresponding actual physical quantity value of the corresponding internal circuit module.

[0057] For example Figure 4 As shown in , the first input of the level 1 inner loop control circuit 320-1 is used to sample the physical quantity P1, and the sampled value of the physical quantity P1 enters the inner loop 1 operation after signal processing and analog-to-digital conversion; the second input receives the output value of the outer loop control circuit 310 (the outer loop control quantity). By performing the inner loop 1 operation on the processed sampled value of the physical quantity P1 and the output value of the outer loop control circuit 310, the output value of the level 1 inner loop control circuit 320-1, that is, the first inner loop control quantity, can be obtained. Further, the first input of the level 2 inner loop control circuit 320-2 samples the physical quantity P2, and the sampled value of the physical quantity P2 enters the inner loop 2 operation after signal processing and analog-to-digital conversion; the second input receives the output value of the level 1 inner loop control circuit 320-1 (the first inner loop control quantity).

[0058] In some embodiments, the output value of the last level inner loop control circuit (e.g., M-level inner loop control circuit 320-m) in a multi-level inner loop control circuit can be input into the switch tube drive generation module 330 to generate a closed-loop control quantity for controlling the output of the high voltage generator.

[0059] In some embodiments, the control device 300 can limit the value of at least one of the multiple inner loop control quantities corresponding to the multi-stage inner loop control circuit. In some embodiments, the value range of the corresponding inner loop control quantity can be dynamically determined according to the physical quantity and / or the target output state. In some embodiments, the value range may include an upper limit and / or a lower limit of the value of the inner loop control quantity. By limiting the value, the current output state can be quickly switched to the target output state, and / or it can be prevented from crossing a critical value (e.g., a maximum value), thereby protecting the current and voltage stress of the internal components of the high voltage generator.

[0060] It should be noted that the above description of the control device 300 is provided for illustrative purposes only and is not intended to limit the scope of this specification. For those of ordinary skill in the art, various changes and modifications can be made according to the description of this specification. However, these changes and modifications do not depart from the scope of this specification.

[0061] Figure 5 It is a schematic diagram of the structure of a limiting module of an exemplary inner loop control quantity shown in some embodiments of this specification.

[0062] In some embodiments, each level of control circuit (e.g., outer loop control circuit 310, inner loop control circuit 320) can obtain the setting value of the next level of control circuit by processing the output value of the control circuit of that level. In some embodiments, the value range of the inner loop control quantity corresponding to the current inner loop control circuit can be determined based on the physical quantity and / or target output state corresponding to the inner loop control circuit; the inner loop setting value of the inner loop control circuit is determined based on the value range and the outer loop control quantity (or the inner loop control quantity output by the inner loop control circuit of the previous level); the inner loop control quantity of the inner loop control circuit is determined based on the inner loop setting value and the physical quantity. In some embodiments, the target output state may include an output voltage command value (e.g., a target output voltage) and an output current command value of a high voltage generator.

[0063] In some embodiments, the value range (e.g., upper limit or lower limit) of the inner loop control quantity corresponding to the inner loop control circuit can be determined based on the real-time physical quantity of the internal circuit module coupled to the inner loop control circuit (the actual value of the physical quantity in the circuit at the current moment) and / or the target output state. In some embodiments, the inner loop control quantity of the physical quantity of the internal circuit module coupled to the inner loop control circuit can be determined in real time based on the inner loop setting value corresponding to the inner loop control circuit and the real-time sampling value of the physical quantity.

[0064] like Figure 5 As shown, the i-1th level control circuit (for example, the outer loop control circuit, or any one of the 1st to M-1st level inner loop control circuits) obtains the output value O of the i-1th level control circuit through the i-1th loop operation (for example, the inner loop operation or the outer loop operation). i-1, based on the target output state or the physical quantity corresponding to the i-th level control circuit (for example, the real-time physical quantity), the upper limit MAX of the amplitude of the i-th level control circuit (for example, any level of the 1st to M-th level inner loop control circuit) is obtained by calculation or by looking up a preset table. i and / or lower limit MIN i , the limit module is based on the output value O i-1 , Upper limit MAX i and / or lower limit MIN i Calculate and get the setting value S of the i-th level control circuit i Furthermore, the i-th level control circuit can be based on its feedback value F i (For example, the physical quantity P i The corresponding sampling value) and the set value S i , get the output value O of the i-th level control circuit i . Where i is greater than 1.

[0065] In some embodiments, the upper and / or lower limits of at least one of the multiple (e.g., M) inner loop control quantities corresponding to the multi-level inner loop control circuit can be determined by calculation or by looking up a preset table based on the target output state. For example, the limiting module corresponding to each level of the control circuit can obtain the corresponding upper and / or lower limits of the amplitude based on the target output state using a preset program instruction. In some embodiments, the upper and / or lower limits of at least one of the multiple inner loop control quantities can be determined by calculation (e.g., substituting into a preset function) or by looking up a preset table based on the target output state and the real-time sampled values ​​of one or more physical quantities. For example, the upper and / or lower limits of the amplitude of the inner loop control quantity of the inner loop control circuit corresponding to the inverter current can be determined by looking up a preset table based on the real-time sampled value of the inverter current and the target output state. Among them, the preset table may include the upper and / or lower limits of the values ​​corresponding to each inner loop control quantity. In some embodiments, the preset table can be constructed based on the target output state and the real-time output values ​​of multiple physical quantities.

[0066] In some embodiments, the upper or lower limit of the value of the inner loop control quantity can be determined according to the value trajectory that changes with time. Among them, the lower limit trajectory line can be used to improve the dynamic performance so that the transient state (current output state) can be quickly switched to the target output state (for example, the target steady state), for example, the CT tube can quickly recover to the output voltage after ignition; the upper limit trajectory line can be used to protect the voltage and current of the internal key points of the high-voltage generator (for example, the inverter current in the high-voltage generator, the series resonant capacitor voltage, etc.) and other stresses.

[0067] As an example only, the first level in the i-level control circuit is an outer loop control circuit, which obtains an outer loop control quantity through an outer loop operation based on the target output voltage and the sampled current output voltage, and then determines the upper and / or lower limits of the amplitude corresponding to the first-level inner loop control circuit (for example, the level 1 inner loop control circuit 320-1) based on the target output state or the first physical quantity P1 by calculation or looking up a preset table (i.e., a lookup table method), thereby determining the first inner loop set value S1 of the first-level inner loop control circuit based on the upper and / or lower limits and the outer loop control quantity. The first-level inner loop control circuit can obtain the output value (first inner loop control quantity) of the first-level inner loop control circuit through inner loop 1 operation based on the first inner loop setting value S1 and the sampling value of the first physical quantity P1, and then determine the upper limit and / or lower limit of the amplitude corresponding to the second-level inner loop control circuit (for example, the 2-level inner loop control circuit 320-2) based on the target output state or the second physical quantity P2 by calculation or looking up a preset table (i.e., a lookup table method), and then determine the second inner loop setting value S2 of the second-level inner loop control circuit. Similarly, based on the second inner loop setting value S2 of the second-level inner loop control circuit and the sampling value of the second physical quantity P2, the output value (second inner loop control quantity) of the second-level inner loop control circuit can be obtained, and then the third inner loop setting value S3 of the third-level inner loop control circuit can be obtained; repeat this process until the inner loop setting value S corresponding to the Mth-level inner loop control circuit is obtained. m The M-th level inner loop control circuit is based on the inner loop setting value S m and physical quantity P m The sampling value is used to obtain the output value O of the M-th level inner loop control circuit. m The switch tube drive generation module 330 is based on the output value O m A control signal can be generated. The control signal can control the output of the high-voltage generator by controlling the connection or blocking of the switch tube in the high-voltage generator, so that it can quickly reach the target steady state.

[0068] When the high-voltage generator needs to switch from the current output state to the target output state, by limiting the lower limit of the value of the inner loop control quantity, it can be quickly switched from the current output state to the target output state; by limiting the upper limit of the value of the inner loop control quantity, it can be avoided that the speed rises too fast and exceeds the standard value (for example, the parallel resonance peak), causing the circuit to lose control, thereby protecting the voltage and current stresses of the internal key points of the high-voltage generator. At the same time, by limiting the values ​​of multiple inner loop control quantities corresponding to the multi-level inner loop control circuit, the rise time of the output value corresponding to each control circuit can be kept consistent or basically consistent, so that the trajectory of the output voltage is within expectations.

[0069] In some embodiments, after the loop operation of each level of control circuit (e.g., outer loop control circuit and inner loop control circuit), a group of value range processing modules (e.g., calculation or preset table query module, and restriction module) can be connected to determine the corresponding set value. In some embodiments, after the loop operation of the outer loop control circuit 310, the 1st level inner loop control circuit 320-1, the 2nd level inner loop control circuit 320-2, ..., the m-1 level inner loop control circuit 320-(m-1) can be connected to a group of value range processing modules.

[0070] Understandably, Figure 5 The description thereof is for illustrative purposes only and is not intended to limit the scope of this specification. For those skilled in the art, various changes and modifications can be made according to the description of this specification. However, these changes and modifications do not depart from the scope of this specification. For example, Figure 5 The calculation or preset table lookup module and the limiting module shown in can be integrated into one module.

[0071] Figure 6 is a schematic diagram of the structure of an exemplary inner loop control circuit according to some embodiments of this specification.

[0072] In some embodiments, the inner loop control circuit can be used to sample one or more physical quantities corresponding to the internal circuit module coupled to it. For example, the inner loop control circuit coupled to the inverter circuit can be used to sample the voltage difference between the inverter current and the bridge arm of the inverter circuit. For another example, the inner loop control circuit coupled to the resonant network can be used to sample the voltage of the series resonant capacitor of the resonant network.

[0073] For example Figure 6 As shown in (a), based on physical quantity a (e.g., inverter current) and physical quantity b (e.g., voltage difference between the bridge arm outputs of the full-bridge circuit), the sampled value of the target physical quantity corresponding to the k-th level inner loop control circuit can be obtained through signal processing, analog domain mathematical processing, and / or analog-to-digital conversion, and the k-th level inner loop control circuit performs inner loop k operation based on the sampled value and its corresponding set value to obtain the output value of the inner loop control circuit of this level. Figure 6 As shown in (b), the sampled value of the target physical quantity corresponding to the k-th level inner loop control circuit can be obtained based on the physical quantity a and the physical quantity b through signal processing, analog-to-digital conversion, digital domain mathematical processing, etc. In some embodiments, the sampled value of the target physical quantity can be determined based on the integral value of the initial values ​​of two or more physical quantities.

[0074] Understandably, Figure 6The related descriptions are only examples. In some embodiments, the sampling value of the target physical quantity corresponding to the inner loop control circuit can be determined by other means based on two or more physical quantities, and this specification does not limit this.

[0075] Figure 7 is a flowchart of an exemplary method for controlling a high voltage generator according to some embodiments of the present specification.

[0076] In some embodiments, process 700 may be performed by control device 300. The operational diagram of process 700 presented below is illustrative. In some embodiments, the process may be completed using one or more additional operations not described and / or one or more operations not discussed. In addition, Figure 7 The order in which the operations of flow 700 are illustrated and described below is not intended to be limiting.

[0077] Step 710: When it is detected that the high voltage generator is to switch the current output state to the target output state, the current output voltage and the target output voltage of the high voltage generator are obtained.

[0078] In some embodiments, the current output state may include a state that meets the preset conditions (e.g., the working requirements of the CT device), or a state that does not meet the preset conditions. In some embodiments, the target output state may include a state that meets the preset conditions. For example, the current output state may be a state that meets the working requirements, and the target output state is the next state that meets the working requirements. For another example, the current output state may be a state that does not meet the working requirements, and the target output state is a target steady state that meets the working requirements.

[0079] The current output voltage refers to the real-time output voltage of the high-voltage generator corresponding to the current output state. Correspondingly, the target output voltage refers to the output voltage of the high-voltage generator corresponding to the target output state. Both the current output voltage and the target output voltage are the voltages provided by the high-voltage generator to the tube.

[0080] In some embodiments, the control device 300 may sample the current output voltage of the high voltage generator. In some embodiments, the input end of the outer loop control circuit of the control device 300 may be connected to the output end of the high voltage generator to sample the current output voltage. Figure 4 As shown in , one of the inputs of the outer loop control circuit 310 is connected to the output end of the rectifier filter of the high voltage generator, so as to perform current output voltage sampling.

[0081] In some embodiments, the control device 300 may determine the target output voltage based on the target output state. For example, the corresponding target output voltage may be determined based on the target output state in the scanning protocol of the target object.

[0082] Step 720: determine the outer loop control amount according to the current output voltage and the target output voltage.

[0083] The outer loop control amount may refer to the output value of the outer loop control circuit. In some embodiments, the outer loop control circuit 310 may perform scaling, analog or digital filtering, lead or lag compensation, etc. on the sampled current output voltage. In some embodiments, the outer loop control circuit 310 may determine the outer loop control amount through an outer loop operation based on the processed signal and the target output voltage. In some embodiments, the outer loop control amount may be a digital amount.

[0084] Step 730, obtaining corresponding physical quantities of the internal circuit module of the high voltage generator.

[0085] In combination with the above, the high voltage generator may include multiple internal circuit modules, and accordingly, each module may correspond to one or more physical quantities. In some embodiments, multiple internal circuit modules are coupled and connected to the multi-stage inner loop control circuit in a one-to-one correspondence, and each stage of the inner loop control circuit is used to sample one or more physical quantities corresponding to the internal circuit module coupled thereto. In some embodiments, at least one stage of the multi-stage inner loop control circuit may be coupled to two or more internal circuit modules among the multiple internal circuit modules, for sampling one or more physical quantities corresponding to the two or more internal circuit modules.

[0086] In some embodiments, one of the inputs of the inner loop control circuit of the control device 300 can be connected to an internal circuit module to sample the corresponding physical quantity. Figure 3 As shown in FIG. 1 , one of the input terminals of the level 1 inner loop control circuit 320-1 is connected to the physical quantity P1 for sampling the physical quantity P1; one of the input terminals of the level 2 inner loop control circuit 320-2 is connected to the physical quantity P2 for sampling the physical quantity P2; one of the input terminals of the level M inner loop control circuit 320-m is connected to the physical quantity P m , and carry out the physical quantity P m sampling.

[0087] Step 740: Determine the inner loop control quantity corresponding to the internal circuit module according to the physical quantity and the outer loop control quantity.

[0088] As described above, the inner loop control amount may refer to the output value of the inner loop control circuit. In some embodiments, for each level of the inner loop control circuit, the control device 300 may determine the corresponding inner loop control amount. In some embodiments, the control device 300 may determine the first inner loop control amount of the first inner loop control circuit based on the outer loop control amount and the first physical quantity. For example, by performing an inner loop 1 operation on the sampled value of the processed first physical quantity P1 and the outer loop control amount output by the outer loop control circuit 310, the output value of the level 1 inner loop control circuit 320-1 may be obtained.

[0089] In some embodiments, the value range of the inner loop control quantity can be dynamically determined based on the corresponding physical quantity and / or the target output state. In some embodiments, the value range of the inner loop control quantity can be determined based on the physical quantity and / or the target output state; the inner loop set value can be determined based on the value range and the outer loop control quantity; the inner loop control quantity can be determined based on the inner loop set value and the physical quantity.

[0090] In some embodiments, the value range of the inner loop control amount may include an upper limit and / or a lower limit of the value of the inner loop control amount, and the upper limit or the lower limit is determined according to the value trajectory that changes over time. In some embodiments, the inner loop control amount corresponding to the internal circuit module can be determined by calculation or by looking up a preset table based on the corresponding physical quantity and / or target output state of the internal circuit module.

[0091] As an example only, after obtaining the output value (outer loop control quantity) of the outer loop control circuit, based on the first physical quantity or target output state corresponding to the first-level inner loop control circuit, the upper and lower limits of the corresponding internal circuit module are determined by calculation or by looking up a preset table, and the first inner loop setting value of the first-level inner loop control circuit is obtained based on the upper and lower limits and the outer loop control quantity. The signal generated by the first-level inner loop control circuit based on its first inner loop setting value and feedback value (for example, the sampling value of the first physical quantity) can make the output voltage reach a first threshold value, such as 20%; based on the output value (second inner loop control quantity) of the first-level inner loop control circuit and the upper and lower limits of the inner loop control quantity corresponding to the second inner loop control circuit, the second inner loop setting value of the second-level inner loop control circuit is obtained. The signal generated by the second-level inner loop control circuit based on its second inner loop setting value and feedback value (for example, the sampling value of the second physical quantity) can make the output voltage reach a second threshold value, such as 30%. By limiting the value range of at least one inner loop control variable based on the real-time output value of at least one relevant physical quantity of the high voltage generator, the output voltage can gradually reach a reference value (eg, a target output voltage value).

[0092] As another example, the output voltage of the high-voltage generator can be quickly reached to the target output voltage by adjusting the lower limit trajectory of the physical quantity P1. For another example, the upper limit trajectory of the physical quantity P1 can be adjusted to prevent the current output voltage from crossing its critical value in the process of reaching the target output voltage. For another example, the upper limit trajectory and lower limit trajectory of two or more physical quantities such as the inverter current of the high-voltage generator, the voltage of the series resonant capacitor, the voltage difference between the bridge arm outputs of the full-bridge circuit, the primary voltage of the transformer, and the output current can be adjusted so that the boost time corresponding to the light load and the heavy load remains consistent or substantially consistent.

[0093] In some embodiments, the control device 300 may obtain the target output state, and determine the upper limit and / or lower limit of at least one inner loop control quantity through calculation based on the target output state and / or the corresponding physical quantity. For example, the target output voltage and the target physical quantity may be substituted into a preset mathematical formula for calculation to obtain the upper limit and / or lower limit of the amplitude corresponding to the current inner loop control quantity.

[0094] Step 750: Determine a closed-loop control variable of the high-voltage generator based on the inner-loop control variable to control the high-voltage generator.

[0095] In some embodiments, the inner loop control quantity output by the last stage inner loop control circuit may be used as the closed loop control quantity of the high voltage generator to control the high voltage generator.

[0096] It should be noted that the above description of process 700 is provided for illustrative purposes only and is not intended to limit the scope of this specification. For those of ordinary skill in the art, various changes and modifications can be made according to the description of this specification. However, these changes and modifications do not depart from the scope of this specification.

[0097] The beneficial effects that may be brought about by the embodiments of this specification include but are not limited to: by limiting the upper and lower limits of the reference value of each level of the control circuit, the voltage and current stress protection of multiple key points inside the high-voltage generator is realized while presenting better dynamic performance. It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced may be any one or a combination of the above, or any other possible beneficial effects.

[0098] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements and corrections to this specification. Such modifications, improvements and corrections are suggested in this specification, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of this specification.

[0099] At the same time, this specification uses specific words to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this specification can be appropriately combined.

[0100] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in this specification, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this specification. Although the above disclosure discusses some invention embodiments that are currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this specification. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0101] Similarly, it should be noted that in order to simplify the description disclosed in this specification and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this specification, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the subject matter of this specification are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0102] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of this specification are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0103] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, etc., cited in this specification are hereby incorporated by reference in their entirety. Except for application history documents that are inconsistent with or conflicting with the contents of this specification, documents that limit the broadest scope of the claims of this specification (currently or later attached to this specification) are also excluded. It should be noted that if the descriptions, definitions, and / or use of terms in the materials attached to this specification are inconsistent or conflicting with the contents described in this specification, the descriptions, definitions, and / or use of terms in this specification shall prevail.

[0104] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims

1. A control method for a high voltage generator, characterized in that: include: When it is detected that the high voltage generator is to switch the current output state to the target output state, obtaining the current output voltage and the target output voltage of the high voltage generator; Determine an outer loop control amount according to the current output voltage and the target output voltage; Acquiring corresponding physical quantities of the internal circuit module of the high voltage generator; Determine the inner loop control quantity corresponding to the internal circuit module according to the physical quantity and the outer loop control quantity; the value range of the inner loop control quantity is dynamically determined according to the physical quantity and / or the target output state; A closed-loop control variable of the high-voltage generator is determined based on the inner-loop control variable to control the high-voltage generator.

2. The method according to claim 1, characterized in that The high voltage generator comprises a multi-stage inner loop control circuit, wherein the inner loop control circuit is used to sample the corresponding physical quantity of the internal circuit module coupled thereto, and a plurality of the inner loop control circuits are sequentially connected in series to form the multi-stage inner loop control circuit.

3. The method according to claim 2, characterized in that The high voltage generator comprises a plurality of internal circuit modules, and the plurality of internal circuit modules are coupled and connected with the multi-stage inner loop control circuit in a one-to-one correspondence.

4. The method according to claim 2, characterized in that: The high voltage generator includes a plurality of internal circuit modules, and the multi-stage inner loop control circuit includes at least one stage of inner loop control circuit coupled to two or more internal circuit modules, and the at least one stage of inner loop control circuit is used to sample corresponding physical quantities of the two or more internal circuit modules.

5. The method according to claim 1, characterized in that The internal circuit module includes an inverter circuit, a resonant network, a transformer circuit and a rectifier filter circuit connected in sequence, and the physical quantity includes at least one of the following: an inverter current, a voltage difference between the bridge arms of the inverter circuit, a voltage of a series resonant capacitor of the resonant network, and a primary voltage of the transformer circuit.

6. The method according to claim 1, characterized in that The determining, according to the physical quantity and the outer loop control quantity, a corresponding inner loop control quantity of the internal circuit module comprises: Determining a value range of the inner loop control quantity based on the physical quantity and / or the target output state; Determining an inner loop set value based on the value range and the outer loop control amount; The inner loop control variable is determined based on the inner loop set value and the physical quantity.

7. The method according to any one of claims 1 to 6, characterized in that: The value range of the inner loop control amount includes an upper limit and / or a lower limit of the value of the inner loop control amount, and the upper limit or the lower limit is determined according to a value trajectory that changes with time.

8. The method according to claim 7, characterized in that Determining the value range includes: Based on the corresponding physical quantity of the internal circuit module and / or the target output state, the corresponding inner loop control quantity of the internal circuit module is determined by calculation or by looking up a preset table.

9. A control device for a high voltage generator, characterized in that: include: An outer loop control circuit, wherein an input end of the outer loop control circuit is connected to an output end of the high voltage generator, and is used to sample a current output voltage of the high voltage generator, and determine an outer loop control amount according to the current output voltage and a target output voltage; An inner loop control circuit, one input of the inner loop control circuit is connected to the internal circuit module of the high voltage generator, and is used to sample the corresponding physical quantity of the internal circuit module; another input of the inner loop control circuit is connected to the outer loop control circuit, and is used to determine the corresponding inner loop control quantity of the internal circuit module according to the sampled physical quantity and the outer loop control quantity; the value range of the inner loop control quantity is dynamically determined according to the physical quantity or the target output state; The control device is configured to determine a closed-loop control variable of the high-voltage generator based on the inner-loop control variable to control the high-voltage generator.

10. The device according to claim 9, characterized in that It includes a multi-stage inner loop control circuit, which is coupled to the internal circuit module and is used to sample the corresponding physical quantity of the internal circuit module; wherein a plurality of the inner loop control circuits are connected in series in sequence to form the multi-stage inner loop control circuit.

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