JP2953341B2 - X-ray tube anode high-speed rotation drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anode high-speed rotation drive device for an X-ray tube used in a medical diagnostic device or the like.

[0002]

2. Description of the Related Art Generally, when an X-ray tube anode is rotated at a high speed, an AC voltage of 180 HZ is applied to the stator coil for a certain period of time, and when braking is applied from the high speed rotation, a 50 HZ or 60 HZ is applied to the stator coil. An AC voltage is applied for a certain time. When a voltage is applied to the stator coil, a voltage that is approximately proportional to the frequency is required. Therefore, it is necessary to prepare different voltage sources for high-speed rotation and braking.

For this reason, a conventional X-ray tube anode high-speed rotating apparatus uses an AC power source 1 and a transformer 2 as shown in FIG.
On the secondary side of the AC voltage V ₁ , V ₂ (V ₁ > V ₂ )
Are rectified by the rectifiers 3a and 3b, respectively, and the smoothing (charging) capacitors 4a and 4b are charged.
At the time of high-speed rotation, the contact of the contactor 5a is closed, and the charging voltage of the capacitor 4a is supplied to the inverter 6, where
It is converted to 0 Hz rectangular wave alternating current and applied to the stator coil 9, the contact of the contactor 5 b is closed during braking, and the charging voltage of the capacitor 4 b is applied to the inverter 6 where it is converted to, for example, 60 Hz rectangular wave alternating current. , Applied to the stator coil 9.

[0004] In the above-mentioned conventional apparatus, two circuits for generating different charging voltages for high-speed rotation and braking are required. Therefore, there is a problem that the circuit becomes complicated. In order to solve this problem, in order to rotate the X-ray tube anode at a high speed or apply braking, the voltage charged in the charging circuit is converted into AC by an inverter and applied to the stator coil. It is preferable that the charging circuit has only one circuit during high-speed rotation and during braking, and controls a voltage applied from the inverter to the stator coil to a pulse width of an inverter driving pulse.

[0005]

In the above-mentioned X-ray tube anode high-speed rotation drive device for controlling the pulse width of the inverter drive pulse, the inverter drive pulse width sent to the inverter is constant at the time of high-speed rotation and at the time of braking, respectively. Since it is fixed, when the power supply voltage fluctuates and the charging voltage of the smoothing capacitor fluctuates, a rectangular wave alternating current having the fluctuated peak value is applied to the stator coil. For this reason, there is a possibility that an excessively high voltage is applied to the stator coil to apply extra heat to the stator coil, or a too low voltage is applied to cause a problem that the number of rotations of the anode becomes insufficient. The present invention has been made in view of the above problems,
Provided is an X-ray tube anode high-speed rotation drive device that has only one charging circuit, yet can smoothly control during high-speed rotation and braking, and can obtain a stable anode rotation speed even if the charging voltage fluctuates. It is intended to be.

[0006]

The X-ray tube anode high-speed rotation driving device of the present invention rotates the X-ray tube anode at high speed,
Alternatively, in order to apply braking, the voltage charged in the charging circuit is converted into AC by an inverter and applied to the stator coil, and the charging circuit has only one during high-speed rotation and during braking, and A voltage to be applied to the stator coil is obtained by controlling a pulse width of an inverter drive pulse, and a charging voltage detection circuit for detecting a voltage of the charging circuit is provided. The pulse width is controlled.

In this X-ray tube anode high-speed rotation driving device, in the case of high-speed rotation, the inverter driving circuit switches to the inverter.
For example, a signal having a wider pulse width is provided at a frequency of 180 Hz, and a signal having a wider pulse width at a frequency of 60 Hz, for example, is provided from the inverter drive circuit to the inverter during braking.

Further, the control is performed so that the pulse width becomes narrower when a large charging voltage is detected, and conversely, the pulse width is widened when the charging voltage is small.

[0009]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a circuit diagram showing a configuration of an X-ray tube anode high-speed rotation driving device which is a premise of one embodiment of the present invention. This X-ray tube anode high-speed rotation driving device receives a AC voltage from an AC power supply 1 and boosts the transformer 2, a rectifier 3 that rectifies a secondary voltage of the transformer 2, and smoothes a DC output of the rectifier 3, A capacitor 4 to be charged and a capacitor 4
The inverter 6 converts the DC voltage to 180 Hz or 60 Hz into an AC voltage and outputs the AC voltage. The inverter 6 supplies the wide pulse shown in FIG.
An inverter driving circuit 7 for inputting a narrow pulse at a frequency of HZ, a phase capacitor 8, and an X-ray tube stator coil 9 for rotating or braking the X-ray tube anode at high speed.
And

In this X-ray tube anode high-speed rotation driving device, an AC voltage from an AC power supply 1 is boosted by a transformer 2, rectified by a rectifier 3, and its output is charged into a capacitor. That is, it is smoothed. The drive signal sent from the inverter drive circuit 7 to the inverter 6 is 18
0HZ, wide, 60HZ, narrow when braking,
The waveform between X and Y of the X-ray tube stator coil 9 is as shown in FIG. This waveform, during braking and during high-speed rotation, the peak value V _a and V _b is, although a V _a = V _b, the pulse pause time T _a and T _b, made to be T _a <T _b ing. In the conventional apparatus, a pause period T _a and T _b are substantially the same as shown in FIG. 5, the peak value is different from that of a V _a> V _b.

The reason for this is that in this device, the inverter 6
This is because it is necessary to make the peak value the same in order to form one system of the charging circuit of the DC voltage applied to the motor, and to make the effective value of the voltage applied to the stator coil 9 at the time of braking smaller than that at the time of high speed rotation. . In this device, the pulse width is made wide at the time of high-speed rotation and narrow at the time of braking. Therefore, only one DC voltage input system to the inverter is required, and the X-ray tube anode high-speed rotation driving device is a simple circuit. Can be realized.

In the above apparatus, the transformer 2 may be omitted if a sufficient output can be obtained with the voltage of the AC power supply 1. FIG. 2 is a circuit diagram showing an X-ray tube anode high-speed rotation driving device according to one embodiment of the present invention. In the device of FIG. 1 described above, the inverter drive pulse width sent to the inverter is fixed at a constant value during high-speed rotation and during braking, respectively.
When the power supply voltage fluctuates and the charging voltage of the smoothing capacitor fluctuates, rectangular wave alternating current having the fluctuated peak value is applied to the stator coil. For this reason, there is a possibility that an excessively high voltage is applied to the stator coil to apply extra heat to the stator coil, or a too low voltage is applied to cause a problem that the number of rotations of the anode becomes insufficient.

The apparatus of the embodiment shown in FIG. 2 can eliminate the above-mentioned fear. The configuration of the apparatus of this embodiment is almost the same as that of the apparatus of FIG.
Is characterized in that a charging voltage detection circuit 10 for detecting the voltage between both ends is provided, and the width of a driving pulse signal supplied from the inverter driving circuit 7 to the inverter 6 is controlled by the magnitude of the detected charging voltage. .

In this embodiment, the AC voltage is boosted by the transformer 2, rectified by the rectifier 3, and the output is charged in the capacitor 4. The charging voltage of the capacitor 4 is detected by the charging voltage detecting circuit 10 and an analog signal proportional to the detected voltage is sent to the inverter driving circuit 7. In the inverter drive circuit 7, when this analog signal is large,
That is, when the power supply voltage is high, the width of the inverter drive pulse signal sent to the inverter 6 is shortened, as shown in FIG.

Conversely, when the analog signal input to the inverter drive circuit 7 is small, that is, when the power supply voltage is low,
As shown in FIG. 6C, the width of the inverter drive pulse signal is increased. In this way, even if the power supply voltage fluctuates, an inverter driving pulse having an optimum pulse width is always sent to the inverter 6, and as a result, the optimum voltage is also applied to the X-ray tube stator coil 9.

In this embodiment, the transformer 2 may be omitted if a sufficient output can be obtained only by the voltage from the AC power supply 1.

[0017]

According to the present invention, the pulse width of the voltage applied to the stator coil is set to a different value during the high-speed rotation of the X-ray tube anode and at the time of braking. Therefore, only one charging circuit for inputting a voltage to the inverter can be provided, and an X-ray tube anode high-speed rotation driving device can be realized with a simple circuit configuration. In addition, since the optimum voltage can always be applied to the X-ray tube stator coil regardless of the fluctuation of the power supply voltage, an excessively high voltage is applied to the stator coil to give extra heat to the stator coil, Does not occur when the voltage of the anode is too low and the number of rotations of the anode becomes insufficient.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of an X-ray tube anode high-speed rotation driving device which is a premise of the present invention.

FIG. 2 is a circuit diagram showing a configuration of an X-ray tube anode high-speed rotation driving device according to one embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a conventional X-ray tube anode high-speed rotation drive device.

FIG. 4 is a diagram illustrating waveforms applied to an X-ray tube stator coil of the apparatus of FIG.

FIG. 5 is a diagram illustrating waveforms applied to an X-ray tube stator coil of a conventional X-ray tube anode high-speed rotation drive device.

FIG. 6 is a diagram for explaining an inverter drive pulse signal of the embodiment device of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 3 Rectifier 4 Smoothing capacitor 6 Inverter 7 Inverter drive circuit 9 X-ray tube stator coil

Claims (1)

(57) [Claims] 1. An X-ray tube anode high-speed rotation driving device for converting a voltage charged in a charging circuit into AC by an inverter and applying the AC voltage to a stator coil to rotate the X-ray tube anode at high speed or to apply braking. there, the charging circuit has only over time and braking time of high speed rotation, a voltage applied from the inverter to the stator coil, so as to obtain by controlling the pulse width of the inverter driving pulse, and the charging circuit Detect voltage
Charge voltage detection circuit that detects
An X-ray tube anode high-speed rotation drive device wherein the pulse width is controlled .