X-ray high-voltage generator KV voltage control method
By acquiring the KV sampling feedback signal in the X-ray high voltage generator and performing notch filtering, the noise disturbance problem caused by power frequency AC fluctuations was solved, and high-precision KV voltage output was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU POWERSITE ELECTRIC CO LTD
- Filing Date
- 2022-10-09
- Publication Date
- 2026-05-08
AI Technical Summary
In X-ray high voltage generators, fluctuations in power frequency AC power cause noise disturbances in the KV sampling circuit, affecting the accuracy of KV voltage output.
By acquiring the KV sampling feedback signal, notch filtering is performed on the target interference frequency to generate the KV filter signal, and the drive circuit is controlled based on the error to output a high-precision KV voltage.
It effectively reduces noise interference from power frequency and improves the output accuracy of KV voltage.
Smart Images
Figure CN115665955B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of KV voltage control, specifically to a KV voltage control method for an X-ray high voltage generator. Background Technology
[0002] X-ray inspection has important applications in hospital patient diagnosis, industrial non-destructive testing, and railway station security checks. As a core component of X-ray inspection, the high-voltage generator has extremely stringent performance parameter requirements in practical applications.
[0003] With the successive application of voltage multiplier circuits and full-wave rectifier circuits, a power supply device emerged that boosts and then multiplies the AC power from the mains frequency to supply high-voltage DC power to the cathode and anode of the X-ray tube. Due to the use of a high-voltage transformer and voltage multiplier circuit, the X-ray tube achieved a higher tube voltage, significantly improving its penetrating power. The input side of the high-voltage generator receives the AC input voltage from the mains power supply, which is converted into a DC bus voltage after passing through the rectifier unit. The input terminal of the closed-loop controlled inverter unit receives the DC bus voltage.
[0004] In actual power supply devices, fluctuations such as power frequency (50Hz) can enter the KV feedback signal through ground coupling, causing noise disturbances in the KV sampling circuit, affecting the closed-loop regulation of KV, and thus affecting the accuracy of KV voltage output. Summary of the Invention
[0005] This application provides a KV voltage control method for an X-ray high voltage generator, which reduces noise disturbance in the KV sampling circuit and improves the KV voltage output accuracy. The technical solution is as follows.
[0006] On the one hand, a method for controlling the KV voltage of an X-ray high-voltage generator is provided, the method being executed by a target processor, the method comprising:
[0007] Acquire the KV sampling feedback signal; the KV sampling feedback signal is obtained by sampling the KV voltage using an analog circuit.
[0008] For the target interference frequency, the KV sampling feedback signal is subjected to notch filtering to obtain the KV filtered signal;
[0009] Based on the first error between the KV filtered signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal, the drive circuit is controlled to output the KV voltage of the X-ray high voltage generator.
[0010] In another aspect, a KV voltage control device for an X-ray high-voltage generator is provided, the device comprising:
[0011] The sampling feedback signal acquisition module is used to acquire the KV sampling feedback signal; the KV sampling feedback signal is obtained by sampling the KV voltage through an analog circuit.
[0012] The notch filter module is used to perform notch filtering on the KV sampled feedback signal for the target interference frequency to obtain the KV filtered signal;
[0013] The drive control module is used to control the drive circuit based on a first error between the KV filter signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal, so as to output the KV voltage of the X-ray high voltage generator.
[0014] In one possible implementation, the step of performing notch filtering on the KV sampled feedback signal for the target interference frequency to obtain a KV filtered signal includes:
[0015] The KV sampling feedback signal is converted from analog to digital to obtain the KV sampling digital signal;
[0016] For the target interference frequency, the target processor performs notch filtering on the KV sampled digital signal to obtain the KV filtered signal.
[0017] In one possible implementation, the step of performing notch filtering on the KV sampled digital signal by the target processor to obtain the KV filtered signal for the target interference frequency includes:
[0018] The target processor calls a digital notch filter at the target interference frequency to process the KV sampled digital signal to obtain the KV filtered signal.
[0019] The continuous-time transfer function of the data notch filter is G(s) = (s... 2 +ω n 2 ) / (s 2 +2ξω n +ω n 2 ), where ω n ξ is the notch center frequency, and ξ is the notch width.
[0020] In one possible implementation, controlling the drive circuit based on a first error between the KV filtered signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal, to output the KV voltage of the X-ray high-voltage generator, includes:
[0021] The driving frequency is generated based on the first error between the KV filtered signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal.
[0022] Based on the driving frequency, the driving circuit is controlled to output the KV voltage of the X-ray high voltage generator.
[0023] In one possible implementation, generating the driving frequency based on a first error between the KV filtered signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal, includes:
[0024] The first error and the second error are weighted to obtain a weighted error, and the driving frequency is generated based on the weighted error.
[0025] In one possible implementation, generating the driving frequency based on the weighted error includes:
[0026] The driving frequency is obtained by processing the weighted error using a PID digital control frequency modulation algorithm.
[0027] In one possible implementation, the transfer function of the PID digital control frequency modulation algorithm is G1(s) = K p +K i *S+K d / S, where K p K i With K d These are the preset parameters.
[0028] In another aspect, a computer device is provided, the computer device including a processor and a memory, the memory storing at least one instruction, the at least one instruction being loaded and executed by the processor to implement the above-described X-ray high voltage generator KV voltage control method executed by the target processor.
[0029] In another aspect, a computer-readable storage medium is provided, wherein at least one instruction is stored therein, the at least one instruction being loaded and executed by a processor to implement the above-described method for controlling the KV voltage of an X-ray high-voltage generator executed by a target processor.
[0030] In another aspect, a computer program product or computer program is provided, the computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, causing the computer device to perform the aforementioned X-ray high-voltage generator KV voltage control method executed by the target processor.
[0031] The technical solution provided in this application may include the following beneficial effects:
[0032] First, the KV sampling feedback signal is acquired. Then, notch filtering is applied to the KV sampling feedback signal for the target interference frequency. This yields the first error between the filtered KV signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal. The driving circuit is then controlled to output the KV voltage of the X-ray high-voltage generator. This notch filtering effectively reduces interference from power frequency noise and improves the accuracy of the KV sampling feedback signal, resulting in a high-precision KV voltage. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0034] Figure 1 This is a schematic diagram of the structure of an X-ray high-pressure generator according to an exemplary embodiment.
[0035] Figure 2 This is a flowchart illustrating a KV voltage control method for an X-ray high voltage generator according to an exemplary embodiment.
[0036] Figure 3 This is a control block diagram illustrating a KV voltage control method for an X-ray high-voltage generator executed by a computer device, according to an exemplary embodiment.
[0037] Figure 4 An S-domain block diagram of an X-ray high voltage generator KV voltage control method executed by a computer device, according to an embodiment of this application, is shown.
[0038] Figure 5 This is a flowchart illustrating a KV voltage control method for an X-ray high voltage generator according to an exemplary embodiment.
[0039] Figure 6 This is a control block diagram illustrating a KV voltage control method for an X-ray high voltage generator executed by a control circuit, according to an exemplary embodiment.
[0040] Figure 7 This is a structural block diagram of a KV voltage control device for an X-ray high voltage generator, according to an exemplary embodiment.
[0041] Figure 8 A structural block diagram of a computer device illustrated in an exemplary embodiment of this application is shown. Detailed Implementation
[0042] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0043] It should be understood that the term "instruction" mentioned in the embodiments of this application can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.
[0044] In the description of the embodiments of this application, the term "correspondence" may indicate that there is a direct or indirect correspondence between two things, or that there is an association between two things, or that there is a relationship of instruction and being instructed, configuration and being configured, etc.
[0045] In the embodiments of this application, "predefined" can be achieved by pre-storing corresponding codes, tables or other means that can be used to indicate relevant information in the device (e.g., including terminal devices and network devices). This application does not limit the specific implementation method.
[0046] Figure 1 This is a schematic diagram illustrating the structure of an X-ray high-voltage generator according to an exemplary embodiment. Figure 1 As shown in the embodiment of this application, the input side of the X-ray high voltage generator is the AC input voltage of the grid power supply.
[0047] On the one hand, the AC input voltage of the power grid can be rectified and converted into DC bus voltage (i.e., DC voltage + and DC voltage -). On the other hand, the AC input voltage of the power grid is input to the power module of the X-ray high-voltage generator so that the power module can supply power to the various control modules of the X-ray high-voltage generator.
[0048] In an X-ray high-voltage generator, the inverter unit is connected to the DC bus voltage and converted into an AC voltage inside the X-ray high-voltage generator for input to the high-voltage tank. After rectification and backup voltage through the high-voltage tank, the anode voltage and cathode voltage are generated and applied to the X-ray tube. At this time, the anode voltage and cathode voltage are the KV voltage in the X-ray high-voltage generator.
[0049] The X-ray high voltage generator also includes a system control unit, which can control the anode control unit in the X-ray high voltage generator, so that the anode control unit generates an anode target driving voltage and acts on the X-ray tube.
[0050] The X-ray high-voltage generator also includes a filament control unit, which generates a filament heating current to heat the filament in the X-ray tube, thereby controlling the temperature of the X-ray tube.
[0051] Figure 2 This is a flowchart illustrating a KV voltage control method for an X-ray high-voltage generator according to an exemplary embodiment. The method is executed by a target processor, which can be, for example... Figure 1 The system control unit is shown in the diagram. (As shown in the diagram...) Figure 2 As shown, the KV voltage control method for the X-ray high-voltage generator may include the following steps:
[0052] Step 201: Obtain the KV sampling feedback signal; the KV sampling feedback signal is obtained by sampling the KV voltage using an analog circuit.
[0053] The CT imaging process involves a control console that activates a high-voltage X-ray generator, producing high voltage. This high voltage causes the X-ray tube to emit X-rays. The collimated X-ray beam is then transmitted through a specific layer of the patient's tissue. A detector measures the attenuation of the X-rays transmitted through that layer. This data is processed by a computer, projected onto a screen, and converted into a digital signal. This signal is transmitted to the main computer, which calculates the absorption coefficient of each unit volume of the tissue at that layer, arranges it into a digital matrix, and then converts it into an analog signal. Finally, the cross-sectional image of that layer is displayed on a monitor in different grayscale levels. Changes in the high-voltage value directly affect the X-ray energy. X-ray energy, in turn, directly affects the absorption coefficient of various tissues in the human body.
[0054] X-rays are emitted by bremsstrahlung, a process generated by high-speed electrons striking a target through an X-ray tube. The tube voltage of an X-ray tube is kV. Bremsstrahlung is the radiation produced by the sudden deceleration of high-speed electrons.
[0055] In this embodiment, the KV sampling feedback signal is obtained by sampling the KV voltage using an analog circuit.
[0056] Optionally, in this embodiment of the application, the X-ray high voltage generator may include a sampling feedback circuit, which can sample the KV voltage in real time while the X-ray high voltage generator generates the KV voltage, thereby obtaining a KV sampling feedback signal.
[0057] Optionally, the sampling method for KV voltage can be the ratio method, the energy spectrum endpoint method, the interventional voltage divider method, or the air kerma method.
[0058] After the sampling feedback circuit samples the KV voltage and obtains the KV sampling feedback signal, it can transmit the KV sampling feedback signal to the computer equipment so that the computer equipment can control the KV voltage according to the KV sampling feedback signal.
[0059] Step 202: For the target interference frequency, perform notch filtering on the KV sampling feedback signal to obtain the KV filtered signal.
[0060] In one possible implementation, the KV sampling feedback signal is converted from analog to digital to obtain a KV sampling digital signal; then, for the target interference frequency, the target processor performs notch filtering on the KV sampling digital signal to obtain the KV filtered signal.
[0061] In this embodiment, the control of the KV voltage is obtained through a computer device (i.e., the target processor). During the processing of the target processor, digital signals need to be processed. Therefore, when the sampling feedback circuit samples the KV voltage and obtains the KV sampling feedback signal, the computer device receives the KV sampling feedback signal and first performs analog-to-digital conversion on it, converting the analog signal type KV sampling feedback signal into a digital signal type KV sampling digital signal so that the target processor can process it.
[0062] In one possible implementation, the signal can be input to a target processor, which can sample the analog quantity KV through its internal ADC module, thereby converting the analog signal into a digital signal through sampling processing to obtain the KV sampled digital signal.
[0063] Among them, ADC stands for analog-to-digital converter, which can convert continuous analog signals into discrete digital signals. Only after the analog signals are converted into digital signals can computer devices (i.e., target processors) process them.
[0064] Once the analog signal is converted into a digital signal, the computer device (i.e., the target processor) can perform notch filtering on the digital signal to obtain the KV filtered signal.
[0065] Notch filtering can filter interference noise in specific frequency bands, remove interference from feedback signals, and thus make the feedback signals involved in digital PID control more accurate.
[0066] In one possible implementation, the target processor calls a digital notch filter at the target interference frequency to process the KV sampled digital signal to obtain the KV filtered signal.
[0067] The continuous-time transfer function of this data notch filter is G(s) = (s... 2 +ω n 2 ) / (s 2 +2ξω n +ω n 2 ), where ω n ξ is the notch center frequency, and ξ is the notch width.
[0068] In other words, the digital filter algorithm can be pre-set in this embodiment. That is, the target interference frequency can be set first, and then the target processor can call the digital filter of the target interference frequency to process the KV sampled digital signal. At this time, the KV filtered signal after digital filter processing has filtered out the signal of the target interference frequency compared with the KV sampled digital signal, thereby reducing the interference of the interference signal of the target interference frequency on the KV voltage control process.
[0069] Furthermore, the target interference frequency can be the power frequency of 50Hz. Since the AC voltage that X-ray high voltage generators are generally connected to is 50Hz (i.e., the power frequency), the interference signal brought by the power frequency can easily interfere with the control process of the KV voltage. Therefore, filtering the interference signal of the target interference frequency, including the power frequency, can improve the control accuracy of the KV voltage.
[0070] Step 203: Based on the first error between the KV filter signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal, the drive circuit is controlled to output the KV voltage of the X-ray high voltage generator.
[0071] The drive circuit is located between the main circuit and the control circuit, and is an intermediate circuit used to amplify the signals from the control circuit.
[0072] In one possible implementation, a driving frequency is generated based on a first error between the KV filtered signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal. Based on this driving frequency, the driving circuit is controlled to output the KV voltage of the X-ray high-voltage generator. In other words, the target processor can compare and analyze the real-time acquired and filtered KV filtered signal with a pre-set target KV signal, and also compare and analyze the target KV signal with the acquired KV sampling feedback signal, thereby determining whether the KV voltage being output by the X-ray high-voltage generator meets expectations. If it does not meet expectations, the driving circuit can be controlled based on the first error between the KV filtered signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal, so that the output KV voltage is closer to the expected value.
[0073] Optionally, the first error and the second error are weighted to obtain a weighted error, and the driving frequency is generated based on the weighted error.
[0074] In one possible implementation, the target processor compares and analyzes the KV filtered signal with the target KV signal, and also compares and analyzes the target KV signal with the acquired KV sampling feedback signal. It obtains the average error values of the KV filtered signal and the target KV signal, and the target KV signal and the KV sampling feedback signal, respectively, within a specified time period. These average errors are then weighted to obtain a weighted average error value. When the weighted average error value is greater than a weighted error threshold, the driving circuit is controlled based on the weighted average error value. When the weighted average error value is less than the weighted error threshold, the output magnitude of the KV voltage remains unchanged.
[0075] Considering the potential errors in the KV voltage sampling process and notch filtering, the target processor can average and weight the errors between the KV filter signal and the target KV signal, as well as the errors between the target KV signal and the KV sampling feedback signal, over a specified period of time (i.e., within a specified time period), to obtain a weighted average error. If the weighted average error is greater than the weighted error threshold, it indicates that the actual output KV voltage differs significantly from the expected value, thus requiring control through the drive circuit. When the weighted average error is less than the weighted error threshold, it may be due to errors introduced during the sampling or notch filtering process, so the KV voltage can be temporarily left uncorrected.
[0076] In one possible implementation, the weighted error is processed by a PID digital control frequency modulation algorithm to obtain the driving frequency.
[0077] In one possible implementation, the transfer function of the PID digital control frequency modulation algorithm is G1(s) = K p +K i *S+K d / S, where K p K i With K d These are the preset parameters.
[0078] Please refer to Figure 3 It shows a control block diagram of a KV voltage control method for an X-ray high voltage generator executed by a computer device, according to an embodiment of this application.
[0079] In the control process of KV voltage, the error between the KV voltage setpoint and the KV sampling feedback signal is first obtained. Then, the error is adjusted by the digital PID module of the target processor and applied to the drive circuit of the inverter. Finally, the expected KV voltage is obtained through the voltage doubler rectifier circuit.
[0080] The inverter converts DC power to AC power, while the voltage doubler rectifier circuit rectifies the AC input voltage by a factor of 1 and outputs a DC voltage.
[0081] Please refer to Figure 4 This illustrates an S-domain block diagram of a KV voltage control method for an X-ray high-voltage generator executed by a computer device, according to an embodiment of this application. Figure 4 As shown, Y(s) is the given KV voltage; U(s) is the KV voltage output; G2(s) is the transfer function of the notch filter; U1(s) is the output voltage of the KV voltage after processing by the notch filter; G1(s) is the PID control frequency modulation; U2(s) is the PID control frequency modulation output; G3(s) is the transfer function of the inverter module and the voltage doubler rectifier module; E1(s) is the error between the given KV voltage and the KV voltage after processing by the notch filter; E2(s) is the error between the given KV voltage and the KV voltage output sampling.
[0082] Optionally, first obtain the KV analog quantity sampling feedback U0, the KV setpoint value at time t=k is y(k), and the current KV voltage analog quantity sampling feedback signal input is u(k).
[0083] Furthermore, the KV analog quantity sampling feedback U1 is obtained, which is obtained by digital notch filtering of the KV voltage noise in a specific frequency band.
[0084] Optionally, the processing procedure for E1(s) is as follows:
[0085] The transfer function of the notch filter in the continuous time domain is G(s)=(s 2 +ω n 2) / (s 2 +2ξω n +ω n 2 Discretize the z to obtain G(z) = (a0z) 2 +a1z+a2) / (b0z 2 +b1z+b2). Let the current KV voltage analog quantity sampling feedback signal input at time t=k be u(k), and the previous and previous inputs be u(k-1) and u(k-2) respectively; the current output is u1(k), and the previous and previous outputs are u1(k-1) and u1(k-2).
[0086] At this point, according to the discretization formula, we get:
[0087] u1(k)=1 / b2*(a0u(k)+a1u(k-1)+a2u(k-2)-b0u1(k-2)-b1u1(k-1));
[0088] u(k-1)=u(k);
[0089] u(k-2) = u(k-1);
[0090] u1(k-1)=u1(k);
[0091] u1(k-2) = u1(k-1);
[0092] At time t=k=0, u1(k-2)=u1(k-1)=u1(k)=0, u(k-2)=u(k-1)=u(k)=0.
[0093] Therefore, at time t = k, the first error of the KV voltage is e1(k) = y(k) – u1(k).
[0094] Optionally, the processing procedure for E2(s) is as follows:
[0095] At time t = k, the current KV voltage analog quantity sampling feedback signal input is u(k). At this time, according to the discretization formula, the second error e2(k) = y(k) – u(k) is obtained.
[0096] Optionally, the processing procedure for G1(s) is as follows:
[0097] The input of G1(s) is divided into two paths, E1(s) and E2(s). Let E(s) = (1-α)E1(s) + αE2(s), where α is the error input weighting factor for the two paths, and G1(s) = K p +K i *S+K d / S. After discretization, let time t = k, the current input be e(k), and the previous and previous-eighths inputs be e(k-1) and e(k-2) respectively; the current output is u2(k), and the previous and previous-eighths outputs are u2(k-1) and u2(k-2) respectively. At this point, according to the discretization formula, we get:
[0098] u2(k)=u2(k-1)+k p (e(k)-e(k-1))+k i e(k)+k d (e(k)-2e(k-1)+e(k-2));
[0099] u2(k-1)=u2(k);
[0100] e(k-1) = e(k);
[0101] e(k-2) = e(k-1);
[0102] At time t=k=0, e(k-2)=e(k-1)=e(k)=0, u2(k-1)=u2(k)=0.
[0103] Optionally, the processing procedure for G3(s) is as follows:
[0104] The signal of the output frequency of U2(s) after processing G1(s) is applied to the inverter circuit after passing through the drive circuit. After filtering, voltage multiplication and rectification, the high voltage generator obtains the corresponding KV voltage.
[0105] In summary, this method first acquires the KV sampling feedback signal, then performs notch filtering on the KV sampling feedback signal targeting the target interference frequency. This yields the first error between the filtered KV signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal. The resulting error is used to control the drive circuit and output the KV voltage of the X-ray high-voltage generator. This notch filtering effectively reduces interference from power frequency noise and improves the accuracy of the KV sampling feedback signal, ultimately resulting in a high-precision KV voltage.
[0106] In such Figure 2 In the illustrated embodiment, a digital notch filter can be invoked via the CPU to perform notch filtering on the KV sampling feedback signal. Those skilled in the art can also implement notch filtering on the KV sampling feedback signal using circuitry; please refer to [reference needed]. Figure 5 , Figure 5 This is a flowchart illustrating a KV voltage control method for an X-ray high-voltage generator according to an exemplary embodiment. The method comprises a control circuit in the X-ray high-voltage generator (…). Figure 1 (Not shown in the image) Execute. For example... Figure 5 As shown, the KV voltage control method for the X-ray high-voltage generator may include the following steps:
[0107] Step 501: The notch filter circuit receives the KV sampling feedback signal.
[0108] In this embodiment of the application, the KV sampling feedback signal is obtained by sampling the KV voltage.
[0109] Optionally, in this embodiment of the application, the X-ray high voltage generator may include a sampling feedback circuit, which can sample the KV voltage in real time while the X-ray high voltage generator generates the KV voltage, thereby obtaining a KV sampling feedback signal.
[0110] Optionally, the sampling method for KV voltage can be the ratio method, the energy spectrum endpoint method, the interventional voltage divider method, or the air kerma method.
[0111] After the sampling feedback circuit samples the KV voltage and obtains the KV sampling feedback signal, it can transmit the KV sampling feedback signal to the control circuit so that the control circuit can control the KV voltage according to the KV sampling feedback signal.
[0112] In one possible implementation, the control circuit includes a notch filter circuit and an analog PID circuit.
[0113] The notch filter circuit in this embodiment can be based on, for example... Figure 2 The notch filter in the illustrated embodiment is designed based on its transfer function, meaning the notch filter circuit in this embodiment can achieve the same functionality as... Figure 2 The digital notch filter in the illustrated embodiment functions similarly to filter the KV sampling feedback signal for target interference frequencies.
[0114] Step 502: The KV sampling feedback signal is notched using the notch filter circuit for the target interference frequency to obtain the KV filtered signal, and the KV filtered signal is sent to the analog PID circuit.
[0115] In one possible implementation, the KV voltage is first sampled by a KV sampling feedback circuit to obtain a KV sampling feedback signal. Then, the obtained KV sampling feedback signal is input into a notch filter circuit. For the target interference frequency, the KV sampling feedback signal is notched by the notch filter circuit to obtain a KV filtered signal.
[0116] Notch filtering can filter interference noise in specific frequency bands, remove interference from feedback signals, and thus make the feedback signal input to the analog PID circuit more accurate.
[0117] In other words, in this embodiment, a notch filter circuit can be pre-built, meaning the target interference frequency can be set first, and then the KV sampling feedback signal can be processed by the notch filter circuit. The KV filtered signal processed by the notch filter circuit, relative to the KV sampling feedback signal, filters out the signal of the target interference frequency, thereby reducing the interference of the target interference frequency signal on the KV voltage control process.
[0118] In one possible implementation, the notch filter circuit has a noise gain of 0 in the target interference frequency band.
[0119] Optionally, in this embodiment, the notch filter can be implemented as a band-stop filter that filters the target frequency, and the noise gain of the band-stop filter in the target interference frequency band is 0. That is, when the KV sampling feedback signal passes through the band-stop filter, the signal in the target interference frequency band will be suppressed, while the signal in the non-target interference frequency band can pass normally, thereby achieving noise filtering of the KV sampling feedback signal in the target interference frequency band. Optionally, in this embodiment, an LC oscillator structure can be used to implement the notch filter circuit for noise filtering in the target interference frequency band.
[0120] Furthermore, the target interference frequency can be the power frequency of 50Hz. Since the AC voltage that X-ray high voltage generators are generally connected to is 50Hz (i.e., the power frequency), the interference signal brought by the power frequency can easily interfere with the control process of the KV voltage. Therefore, filtering the interference signal of the target interference frequency, including the power frequency, can improve the control accuracy of the KV voltage.
[0121] In one possible implementation, the notch filter circuit can send the resulting KV filtered signal to the analog PID circuit via a subtractor.
[0122] The subtractor, also known as a differential amplifier circuit, takes multiple signals as input and outputs the difference between them. The subtractor amplifies differential signals and suppresses common-mode signals.
[0123] Step 503: Based on the KV reference voltage, the KV filter signal is processed by the analog PID circuit, and the driving circuit is controlled by the processing result.
[0124] The drive circuit is located between the main circuit and the control circuit, and is an intermediate circuit used to amplify the signals from the control circuit.
[0125] In one possible implementation, the control circuit can also set a KV voltage setpoint, compare the KV voltage setpoint with the KV filter signal, and control the drive circuit based on the comparison error, thereby controlling the KV voltage of the X-ray high voltage generator.
[0126] In other words, the control circuit can compare and analyze the KV filter signal that is acquired and filtered in real time with the preset KV voltage setpoint to determine whether the KV voltage being output by the X-ray high voltage generator meets expectations. If it does not meet expectations, the drive circuit can be controlled according to the error between the KV filter signal and the KV voltage setpoint, so that the output KV voltage is closer to the expected value.
[0127] In one possible implementation, the control circuit compares and analyzes the KV filter signal with the KV voltage setpoint to obtain the average error between the KV filter signal and the KV voltage setpoint over a specified time period. When the average error is greater than the error threshold, the drive circuit is controlled according to the average error. When the average error is less than the error threshold, the output value of the KV voltage is kept unchanged.
[0128] Considering the potential errors in the KV voltage sampling process and notch filtering process, the control circuit can average the error between the KV filter signal and the KV voltage setpoint over a specified period of time. If the average error is greater than the error threshold, it indicates that the actual output KV voltage differs significantly from the expected value, thus requiring control through the drive circuit. When the average error is less than the error threshold, it may be due to errors introduced during the sampling or notch filtering process, so the KV voltage can be temporarily left uncorrected.
[0129] Please refer to Figure 6 The diagram illustrates a control block diagram of a KV voltage control method for an X-ray high-voltage generator executed by a control circuit, according to an embodiment of this application.
[0130] In the PID control process of KV, the error between the KV setpoint and the KV sampling feedback signal is first obtained. Then, the error is adjusted by the analog PID circuit. This adjustment is then applied to the inverter's drive circuit, and the expected KV value is obtained through the voltage doubler rectifier circuit.
[0131] The inverter converts DC power to AC power, while the voltage doubler rectifier circuit rectifies the AC input voltage by a factor of 1 and outputs a DC voltage.
[0132] The target quantity of an analog PID circuit can be set in advance. The input of the analog PID circuit is a control quantity that can be set for easy processing by the PID controller. This control quantity passes through proportional, integral, and derivative components, and is then fed back by the feedback component. Based on the feedback result, the control quantity is corrected so that it approaches the set target quantity infinitely, thereby achieving the purpose of PID control.
[0133] In summary, this method first acquires the KV sampling feedback signal, then performs notch filtering on the KV sampling feedback signal targeting the target interference frequency. This yields the first error between the filtered KV signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal. The resulting error is used to control the drive circuit and output the KV voltage of the X-ray high-voltage generator. This notch filtering effectively reduces interference from power frequency noise and improves the accuracy of the KV sampling feedback signal, ultimately resulting in a high-precision KV voltage.
[0134] Figure 7 This is a structural block diagram illustrating a KV voltage control device for an X-ray high-voltage generator according to an exemplary embodiment. The KV voltage control device for the X-ray high-voltage generator includes:
[0135] The sampling feedback signal acquisition module is used to acquire the KV sampling feedback signal; this KV sampling feedback signal is obtained by sampling the KV voltage through an analog circuit.
[0136] The notch filter module is used to perform notch filtering on the KV sampled feedback signal for the target interference frequency to obtain the KV filtered signal.
[0137] The drive control module is used to control the drive circuit based on the first error between the KV filter signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal, so as to output the KV voltage of the X-ray high voltage generator.
[0138] In one possible implementation, the KV sampled feedback signal is notched for the target interference frequency to obtain a KV filtered signal, including:
[0139] The KV sampling feedback signal is converted from analog to digital to obtain the KV sampling digital signal;
[0140] For the target interference frequency, the target processor performs notch filtering on the KV sampled digital signal to obtain the KV filtered signal.
[0141] In one possible implementation, the KV sampled digital signal is subjected to notch filtering by the target processor to obtain the KV filtered signal, targeting the interference frequency, including:
[0142] The target processor calls a digital notch filter at the target interference frequency to process the KV sampled digital signal and obtain the KV filtered signal.
[0143] The continuous-time transfer function of this data notch filter is G(s) = (s... 2 +ω n2 ) / (s 2 +2ξω n +ω n 2 ), where ω n ξ is the notch center frequency, and ξ is the notch width.
[0144] In one possible implementation, the drive circuit is controlled based on a first error between the KV filtered signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal, to output the KV voltage of the X-ray high-voltage generator, including:
[0145] The driving frequency is generated based on the first error between the KV filtered signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal.
[0146] Based on this driving frequency, the driving circuit is controlled to output the KV voltage of the X-ray high voltage generator.
[0147] In one possible implementation, generating the driving frequency based on a first error between the KV filtered signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal, includes:
[0148] The first error and the second error are weighted to obtain a weighted error, and the driving frequency is generated based on the weighted error.
[0149] In one possible implementation, generating the drive frequency based on the weighted error includes:
[0150] The driving frequency is obtained by processing the weighted error using a PID digital control frequency modulation algorithm.
[0151] In one possible implementation, the transfer function of the PID digital control frequency modulation algorithm is G1(s) = K p +K i *S+K d / S, where K p K i With K d These are the preset parameters.
[0152] In summary, this method first acquires the KV sampling feedback signal, then performs notch filtering on the KV sampling feedback signal targeting the target interference frequency. This yields the first error between the filtered KV signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal. The resulting error is used to control the drive circuit to output the KV voltage of the X-ray high-voltage generator. This notch filtering effectively reduces interference from power frequency noise and improves the accuracy of the KV sampling feedback signal, ultimately resulting in a high-precision KV voltage.
[0153] Figure 8 A structural block diagram of a computer device 800 illustrated in an exemplary embodiment of this application is shown. This computer device can be implemented as a server as described above in this application. The computer device 800 includes a Central Processing Unit (CPU) 801, a system memory 804 including Random Access Memory (RAM) 802 and Read-Only Memory (ROM) 803, and a system bus 805 connecting the system memory 804 and the CPU 801. The computer device 800 also includes a mass storage device 806 for storing an operating system 809, application programs 810, and other program modules 811.
[0154] The mass storage device 806 is connected to the central processing unit 801 via a mass storage controller (not shown) connected to the system bus 805. The mass storage device 806 and its associated computer-readable media provide non-volatile storage for the computer device 800. That is, the mass storage device 806 may include computer-readable media (not shown) such as a hard disk or a compact disc read-only memory (CD-ROM) drive.
[0155] Without loss of generality, the computer-readable medium may include computer storage media and communication media. Computer storage media include volatile and non-volatile, removable and non-removable media implemented using any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media include RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other solid-state storage technologies, CD-ROM, digital versatile disc (DVD) or other optical storage, magnetic tape cassettes, magnetic tape, disk storage, or other magnetic storage devices. Of course, those skilled in the art will recognize that the computer storage medium is not limited to the above-mentioned types. The system memory 804 and mass storage device 806 described above can be collectively referred to as memory.
[0156] According to various embodiments of this disclosure, the computer device 800 can also be connected to a remote computer on a network, such as the Internet. That is, the computer device 800 can be connected to a network 808 via a network interface unit 807 connected to the system bus 805, or it can use the network interface unit 807 to connect to other types of networks or remote computer systems (not shown).
[0157] The memory also includes at least one computer program stored in the memory, and the central processing unit 801 executes the at least one computer program to implement all or part of the steps in the methods shown in the above embodiments.
[0158] In one exemplary embodiment, a computer-readable storage medium is also provided for storing at least one computer program, which is loaded and executed by a processor to implement all or part of the steps in the above-described method. For example, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, and optical data storage device, etc.
[0159] In one exemplary embodiment, a computer program product or computer program is also provided, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the aforementioned actions. Figure 2 All or part of the steps of the method shown in the embodiments.
[0160] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.
[0161] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.
Claims
1. A method for controlling the KV voltage of an X-ray high-voltage generator, characterized in that, The method is executed by a target processor, and the method includes: Acquire the KV sampling feedback signal; the KV sampling feedback signal is obtained by sampling the KV voltage using an analog circuit. For the target interference frequency, the KV sampling feedback signal is subjected to notch filtering to obtain the KV filtered signal; Based on the first error between the KV filtered signal and the target KV signal, and the second error between the target KV signal and the KV sampling feedback signal, the drive circuit is controlled to output the KV voltage of the X-ray high voltage generator; The method of controlling the drive circuit based on a first error between the KV filtered signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal, to output the KV voltage of the X-ray high-voltage generator, includes: A driving frequency is generated based on a first error between the KV filtered signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal; wherein the first error and the second error are weighted to obtain a weighted error, and the driving frequency is generated based on the weighted error. Based on the driving frequency, the driving circuit is controlled to output the KV voltage of the X-ray high voltage generator.
2. The method according to claim 1, characterized in that, The step of performing notch filtering on the KV sampled feedback signal to obtain a KV filtered signal for the target interference frequency includes: The KV sampling feedback signal is converted from analog to digital to obtain the KV sampling digital signal; For the target interference frequency, the target processor performs notch filtering on the KV sampled digital signal to obtain the KV filtered signal.
3. The method according to claim 2, characterized in that, The step of performing notch filtering on the KV sampled digital signal by the target processor to obtain the KV filtered signal for the target interference frequency includes: The target processor calls a digital notch filter at the target interference frequency to process the KV sampled digital signal to obtain the KV filtered signal. The continuous-time transfer function of the digital notch filter is G(s) = (s... 2 +ω n 2 ) / (s 2 +2ξω n +ω n 2 ), where ω n ξ is the notch center frequency, and ξ is the notch width.
4. The method according to any one of claims 1 to 3, characterized in that, The process of generating the driving frequency based on the weighted error includes: The driving frequency is obtained by processing the weighted error using a PID digital control frequency modulation algorithm.
5. The method according to claim 4, characterized in that, The transfer function of the PID digital control frequency modulation algorithm is G1(s)=K p +K i *S+K d / S, where K p K i With K d These are the preset parameters.
6. A KV voltage control device for an X-ray high-voltage generator, characterized in that, The device includes: The sampling feedback signal acquisition module is used to acquire the KV sampling feedback signal; the KV sampling feedback signal is obtained by sampling the KV voltage through an analog circuit. The notch filter module is used to perform notch filtering on the KV sampled feedback signal for the target interference frequency to obtain the KV filtered signal; The drive control module is used to control the drive circuit based on a first error between the KV filter signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal, so as to output the KV voltage of the X-ray high voltage generator. The drive control module is also used for: A driving frequency is generated based on a first error between the KV filtered signal and the target KV signal, and a second error between the target KV signal and the KV sampling feedback signal; wherein the first error and the second error are weighted to obtain a weighted error, and the driving frequency is generated based on the weighted error. Based on the driving frequency, the driving circuit is controlled to output the KV voltage of the X-ray high voltage generator.
7. A computer device, characterized in that, The computer device includes a processor and a memory, the memory storing at least one instruction, which is loaded and executed by the processor to implement the KV voltage control method for an X-ray high voltage generator as described in any one of claims 1 to 5.
8. A computer-readable storage medium, characterized in that, The storage medium stores at least one instruction, which is loaded and executed by a processor to implement the KV voltage control method for an X-ray high voltage generator as described in any one of claims 1 to 5.
Citation Information
Patent Citations
Adaptive filtering system for filtering power frequency interference based on fuzzy logic
CN104702243A
Variable frequency kV control system for medical diagnostic X-ray high voltage generator
CN109687755A