X-ray high voltage device

• US 20060274887A1
• Filed: 05/24/2004
• Published: 12/07/2006
• Est. Priority Date: 05/23/2003
• Status: Active Grant

• Current Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Inventors: Sakamoto, Kazuhiko, Takano, Hiroshi
• Granted Patent: US 7,327,827 B2
• Time in Patent Office: Days
• US Class Current: 378/104
• CPC Class Codes: H05G 1/12 with dc or rectified single-phase ac or double-phase

Abstract

A semiconductor switch 12 connected in series with a smoothing capacitor 12 is constituted by connecting in parallel a diode 13D which permits to flow current regenerated from energy of electric charges stored in a high voltage capacitor 17 to a primary side of a high voltage transformer 15 for the smoothing capacitor 12 and switching means 13S which interrupts an output from the smoothing capacitor 12, and after turning off the switching means 13S, through alternative on and off control of switching means 161S˜164S the energy of electric charges stored in the high voltage capacitor 17 is regenerated to the smoothing capacitor 12 by making use of parasitic leakage inductance 15L. As a result, an X-ray high voltage device is provided which permits to drop a wave tail of a tube voltage in a high speed without complexing the structure of the high voltage part thereof.

Claims

1. A high voltage device comprising a low voltage DC source, a low voltage side inverter of which input side is connected to the low voltage DC source and inverts the current from the low voltage DC source into high frequency AC voltage and outputs the same, a high voltage transformer of which primary winding is connected to the output side of the low voltage side inverter and boosts up the high frequency AC voltage from the low voltage inverter, a high voltage rectifier of which input side is connected to the secondary winding of the high voltage transformer and which rectifies the AC voltage boosted up by the high voltage transformer, a high voltage side capacitor connected to the output side of the high voltage rectifier and a radioactive ray generation device connected between terminals of the high voltage side capacitor, characterized in that electric charge energy stored in the high voltage side capacitor is regenerated from the output side to the input side via the high voltage transformer.

2. A high voltage device according to claim 1, wherein the high voltage device is further provided with a regenerating means which performs regeneration of the electric charge energy.

3. A high voltage device according to claim 2, characterized in that the regenerating means causes to reduce the voltage at the input side lower than the voltage at the output side.

4. A high voltage device according to claim 2 or 3, characterized in that the regenerating means is provided between the output side of the low voltage DC source and the input side of the high voltage side capacitor.

5. A the high voltage device according to any one of claims 2 through 4, characterized in that the regenerating means is at least a current control means provided between the low voltage DC source and the high voltage transformer.

6. A the high voltage device according to any one of claims 2 through 4, characterized in that the regenerating means is at least provided in the high voltage rectifier.

7. A high voltage device according to any one of claims 2 through 5, characterized in that the regenerating means is the low voltage side inverter.

8. A high voltage device according to claim 5, characterized in that the regenerating means is an element which only allows current conduction from the output side to the input side during regeneration and allows bi-directional current conduction other than the regeneration period.

9. A high voltage device according to claim 8, characterized in that the element is a parallel connection of a diode and a switch.

10. A high voltage device according to claim 6, characterized in that the high voltage rectifier is further provided with a switching element which receives the electric charges in the high voltage side capacitor, inverts the same into an AC and returns the same to the input side.

11. A high voltage device according to claim 6, characterized in that the high voltage rectifier is constituted by a diode bridge and switching elements each of which is connected in parallel with respective diodes constituting the diode bridge.

12. A high voltage device according to any one of claims 1 through 11, characterized in that the high voltage device is further provided with regeneration control means which controls the operation of the regenerating means.

13. A high voltage device according to claim 12, characterized in that the regeneration control means turns off the switch in the current control means provided between the low voltage DC source and the high voltage transformer at the start of the regeneration.

14. A high voltage device according to claim 12 or 13, characterized in that the regeneration control means causes to reduce the voltage of the input side lower than the voltage of the output side by witching the low voltage side inverter.

15. A high voltage device according to any one of claims 12 through 14, characterized in that the regeneration control means inverts the switching element in the high voltage rectifier into AC during the regeneration and returns the energy to the input side.

16. A high voltage device according to claim 15, characterized in that the switching frequency of the low voltage side inverter is higher than the AC frequency of the switching element in the high voltage rectifier.

17. A high voltage device according to any one of claims 1 through 16, characterized in that the radioactive ray generation device is an X-ray tube.

18. A high voltage device according to any one of claims 1 through 17, characterized in that the X-ray tube is a neutral point grounded type X-ray tube and the high voltage rectifier is provided at least in two sets.

19. A high voltage device according to any one of claims 1 through 18, characterized in that the low voltage DC source includes at least one of a capacitor and a battery.

20. An X-ray high voltage device comprising:

a DC power supply means with a low voltage electric charge storing means,

a DC/AC inverting means which inverts the output of the DC power supply means into a high frequency AC voltage and outputs the same,

a high voltage transforming means which boosts up the high frequency AC voltage from the DC/AC inverting means,

a rectifying means which rectifies the boosted up high frequency AC voltage and generates a DC high voltage,

a high voltage electric charge storing means including stray capacitance of cables connected to the output side of the rectifying means, and

an X-ray generating means which is connected between the terminals of the high voltage electric charge storing means and receives DC high voltage from the high voltage electric charge storing means, when an X-ray irradiation command is turned on, and generates X-ray, characterized in that,

the rectifying means is provided with a first regenerating means which causes electric charges to flow in reverse direction from the secondary side to the primary side of the high voltage transforming means and a second regenerating means which causes to regenerate electric charges remained in the high voltage electric charge storing means to the low voltage side DC power supply means via the high voltage transforming means, when the X-ray irradiation command is turned off.

21. An X-ray high voltage device according to claim 20, characterized in that the first regenerating means is a DC/AC inverting means which is incorporated in the rectifying means and the second regenerating means includes a semiconductor element which is connected between the DC power supply means and the DC/AC inverter and allows current conduction only in a direction from the DC/AC inverting means to the DC power supply means, when the X-ray irradiation command is turned off.