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CN-122002678-A - Electronic circuit and method for providing high tube voltage for an X-ray tube, method for operating an X-ray tube, X-ray tube system and medical imaging device

CN122002678ACN 122002678 ACN122002678 ACN 122002678ACN-122002678-A

Abstract

The invention discloses an electronic circuit and a method for providing a high tube voltage for an X-ray tube, a method for operating an X-ray tube, an X-ray tube system and a medical imaging device. The present invention relates to an electronic circuit for providing a high tube voltage for an X-ray tube. The electronic circuit has a first inverter unit configured to receive an input DC voltage and to convert it to a first AC voltage according to a first manipulated variable, and a second inverter unit configured to convert the input DC voltage to a second AC voltage according to a second manipulated variable. The further circuit portion is configured to generate a high tube voltage from the first AC voltage and the second AC voltage. The control device is configured to determine a controlled variable and to change the first manipulated variable (10) and/or the second manipulated variable in dependence on the controlled variable and to determine the controlled variable in dependence on the first alternating current and the second alternating current and/or the first direct current and the second direct current.

Inventors

  • Leopold Ultra
  • Stefan wafler

Assignees

  • 西门子医疗股份公司

Dates

Publication Date
20260508
Application Date
20251104
Priority Date
20241106

Claims (15)

  1. 1. An electronic circuit (1) for providing a high tube voltage (17) for an X-ray tube (18), the electronic circuit (1) having: A first inverter unit (4), the first inverter unit (4) being configured to receive an input DC voltage (2) and to convert the input DC voltage (2) into a first AC voltage (8) according to a first manipulated variable (10), and A second inverter unit (5), the second inverter unit (5) being configured to receive the input DC voltage (2) and to convert the input DC voltage (2) into a second AC voltage (9) according to a second manipulated variable (11), and -A further circuit part (3), the further circuit part (3) being configured to generate the Gao Guan voltage (17) from the first and second AC voltages (8, 9) and to make the Gao Guan voltage (17) available on an output side, and -A control device (24), the control device (24) being configured to determine a controlled variable (25) and to vary the first manipulated variable (10) and/or the second manipulated variable (11) in accordance with the controlled variable (25) in order to control the controlled variable (25) to a predetermined setpoint value (26), wherein the control device (24) is configured to determine the controlled variable (25) in accordance with: i) -a first alternating current (6) generated by said first AC voltage (8) and a second alternating current (7) generated by said second AC voltage (9), and/or Ii) a first direct current (43) generated by the input DC voltage (2) at the first inverter unit (4) and a second direct current (44) generated by the input DC voltage (2) at the second inverter unit (5).
  2. 2. Electronic circuit (1) according to claim 1, wherein the controlled variable (25) depends on a difference between the first alternating current (6) and the second alternating current (7) and/or a difference between the first direct current (43) and the second direct current (44).
  3. 3. Electronic circuit (1) according to claim 1, wherein, -The control device (24) is configured to determine a first characteristic value (27) from the first alternating current (6) and a second characteristic value (28) from the second alternating current (7); -said controlled variable (25) depends on said first characteristic value (27) and said second characteristic value (28), or-said controlled variable (25) depends on the difference between said first characteristic value (27) and said second characteristic value (28); The first characteristic value corresponding to a first effective value, a first integral value or a first peak value, and The second characteristic value corresponds to a second effective value, a second integer value, or a second peak value.
  4. 4. An electronic circuit (1) according to claim 3, wherein the control means (24) is configured to determine a maximum characteristic value from the first characteristic value (27) and the second characteristic value (28), and When the first characteristic value (27) is smaller than the maximum characteristic value, changing the first manipulated variable (10) according to the controlled variable (25), and When the second characteristic value (28) is smaller than the maximum characteristic value, the second manipulated variable (11) is changed according to the controlled variable (25).
  5. 5. Electronic circuit (1) according to one of the preceding claims 1 to 3, wherein the control device (24) is configured to determine a controller manipulated variable (37) from the controlled variable (25) and the predetermined setpoint value (26), and The first manipulated variable (10) is dependent on a difference between a predetermined initial value (40) and the controller manipulated variable (37), and/or The second manipulated variable (11) is dependent on the sum of the predetermined initial value (40) and the controller manipulated variable (37).
  6. 6. The electronic circuit (1) according to one of the preceding claims, wherein the further circuit portion (3) comprises a voltage transformer (15), the voltage transformer (15) being configured to receive a primary alternating voltage (14) generated by the first AC voltage (8) and/or the second AC voltage (9) on a primary side and to convert the primary alternating voltage (14) into a secondary alternating voltage (29), wherein the Gao Guan voltage (17) depends on the secondary alternating voltage (29).
  7. 7. Electronic circuit (1) according to claim 6, wherein the further circuit portion (3) comprises a rectifier (16), the rectifier (16) being configured to convert the secondary alternating voltage (29) into the Gao Guan voltage (17).
  8. 8. Electronic circuit (1) according to one of the preceding claims, wherein, The further circuit part (3) comprises a first resonant circuit (12), the first resonant circuit (12) being coupled on an input side to the output of the first inverter unit (4) and on an output side to the output of the further circuit part (3) configured to provide the Gao Guan voltage (17), and The further circuit portion (3) comprises a second resonant circuit (13), the second resonant circuit (13) being coupled on an input side to an output of the second inverter unit (5) and on an output side to the output of the further circuit portion (3) configured to provide the Gao Guan voltage (17).
  9. 9. The electronic circuit (1) according to claim 8, wherein the output of the first resonant circuit (12) and the output of the second resonant circuit (13) are coupled to each other.
  10. 10. Electronic circuit (1) according to one of the preceding claims, wherein the electronic circuit (1) comprises at least one further inverter unit (30), wherein, Each of the at least one further inverter unit (30) is configured to receive the input DC voltage (2) and to convert the input DC voltage (2) into a respective further AC voltage (31) according to a respective further manipulated variable (33); -the further circuit part (3) is configured to generate the Gao Guan voltage (17) from the further alternating voltage (31); the control device (24) is configured to determine the controlled variable (25) according to: i) -said first alternating current (6), said second alternating current (7) and a corresponding further alternating current (32) generated by said further alternating voltage (31), and/or Ii) the first direct current (43), the second direct current (44) and the respective further direct current generated by the input DC voltage (2) at each of the at least one further inverter unit (30).
  11. 11. X-ray tube system with an electronic circuit (1) according to one of the preceding claims and the X-ray tube (18).
  12. 12. A medical imaging system having an X-ray tube system according to claim 11.
  13. 13. A method for providing a high tube voltage (17) for an X-ray tube (18), wherein: Converting the input DC voltage (2) into a first AC voltage (8) according to a first manipulated variable (10); -converting said input DC voltage (2) into a second AC voltage (9) according to a second manipulated variable (11); -generating the Gao Guan voltage (17) from the first AC voltage (8) and the second AC voltage (9) and making the Gao Guan voltage (17) available; The controlled variable (25) is determined according to: i) -a first alternating current (6) generated by said first AC voltage (8) and a second alternating current (7) generated by said second AC voltage (9), and/or Ii) a first direct current (43) generated by the input DC voltage (2) at the first inverter unit (4) and a second direct current (44) generated by the input DC voltage (2) at the second inverter unit (5), and -Changing the first manipulated variable (10) and/or the second manipulated variable (11) in dependence of the controlled variable (25) in order to control the controlled variable (25) to a predetermined setpoint value (26).
  14. 14. Method according to claim 13, wherein the controlled variable (25) depends on a difference between the first alternating current (6) and the second alternating current (7) and/or on a difference between the first direct current (43) and the second direct current (44), or the controlled variable (25) depends on a difference between a first characteristic value (27) of the first alternating current (6) and a second characteristic value (28) of the second alternating current (7), wherein, The first characteristic value corresponding to a first effective value, a first integral value or a first peak value, and The second characteristic value corresponds to a second effective value, a second integer value, or a second peak value.
  15. 15. Method for operating an X-ray tube (18), wherein a method according to one of claims 13 or 14 is performed and X-rays are generated by means of the X-ray tube (18) in accordance with the Gao Guan voltage (17).

Description

Electronic circuit and method for providing high tube voltage for an X-ray tube, method for operating an X-ray tube, X-ray tube system and medical imaging device Technical Field The present invention relates to an electronic circuit for providing a high tube voltage for an X-ray tube. The invention also relates to an X-ray tube system having such an electronic circuit and a medical imaging system having such an X-ray tube system. The invention also relates to a corresponding method. Background An X-ray tube is a special type of electron beam tube for generating X-rays. X-ray tubes are used in various imaging methods and offer a wide range of possibilities, including in modern medicine. The generation of X-rays by means of an X-ray tube requires free electrons which can be accelerated from the cathode to the anode with the aid of a defined high tube voltage. Electrons released per unit time from the cathode to the anode, i.e., charges, are referred to as tube current. The high tube voltage may typically be in the range of 25 kV to 600 kV. When the accelerated electrons strike the anode, they release energy, which produces energy and characteristic radiation. Since the incident electrons can deflect or scatter in various directions, they release different amounts of energy in the form of bremsstrahlung, depending on the angle of deflection. This creates a continuous X-ray spectrum. The overall efficiency of the X-ray tube system, i.e. the radiation yield in relation to the input energy, may be very low. Thus, it may be necessary to supply an X-ray tube with a very high power, for example of the order of 100 kW. The X-ray tube is conventionally supplied with power by a power electronic conversion chain. For example, this first converts a single-phase or three-phase supply AC voltage into an input DC voltage, which is also referred to as a DC link voltage. In a further step, the DC link voltage is used to generate a high frequency (e.g., 30 kHz to 300 kHz) AC voltage with an adjustable amplitude to the X-ray tube via a transmission circuit. Herein, the transmission circuit may include a resonant circuit, a high voltage transformer, and high voltage rectification. The level of the high frequency AC voltage may be adjusted, for example, by actively regulating the DC link voltage, by phase shifting at least one leg of the inverter, or by varying the frequency of the AC voltage. The purpose of this transmission circuit is to generate a high voltage DC voltage between the anode and the cathode within the tube, which accelerates free electrons from a corresponding heated emitter (also referred to as filament) on one side of the cathode, thereby forming a current within the X-ray tube. This current flow in turn generates high energy X-rays that can be used for medical imaging when it strikes the anode. Since X-ray tubes, in particular for CT and radiography applications, can have a maximum beam power in the range of 100 kW and above, the power transmission can be divided into several stages, for example due to thermal stresses on the components of the inverter stage. This can disadvantageously lead to asymmetric currents and thus to asymmetric power distribution due to unavoidable tolerances in the different stages, for example tolerances of the components in the transmission circuit. Disclosure of Invention The object of the invention is to reduce the asymmetry of the load distribution in a multi-stage supply circuit for high tube voltages of an X-ray tube. This object is achieved by the corresponding subject matter of the main technical features. Advantageous developments and preferred embodiments are the subject of the further technical features, the following description and the figures. The invention is based on the idea of ensuring a more symmetrical load distribution of a multi-stage supply circuit by means of output side control within the framework of AC voltage generation. According to one aspect of the invention, an electronic circuit for providing a high tube voltage for an X-ray tube is presented. The electronic circuit has a first inverter unit configured to receive an input DC voltage and to convert the input DC voltage to a first AC voltage according to a first manipulated variable. Further, the electronic circuit has a second inverter unit configured to receive the input DC voltage and to convert the input DC voltage to a second AC voltage according to a second manipulated variable. Furthermore, the electronic circuit has a further circuit part configured to generate a high tube voltage from the first AC voltage and the second AC voltage and to make the high tube voltage available on the output side, i.e. at the output of the circuit part. Furthermore, the electronic circuit has a control device configured to determine a controlled variable and to change the first manipulated variable and/or the second manipulated variable in dependence on the controlled variable in order to control the controlled var