JPH0512840B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a drive device for rotating an anode of an X-ray tube (rotating anode X-ray tube) installed in an X-ray diagnostic device, etc. In particular, the present invention relates to an anode rotation drive device for an X-ray tube that enables reduction in size and weight.

(Prior art) Rotating anode X-ray tube (hereinafter simply referred to as "X-ray tube")
In this method, a large amount of X-rays can be obtained by rotating the anode and dispersing the heat generated at the anode.

This type of X-ray tube has a rotor connected to the anode inside the nerve vessel, and a coil as a stator on the wall of the vacuum vessel. The stator coil and rotor constitute an induction motor. Here, an anode rotation drive device supplies current to the stator coil, that is, current for rotational drive, and is generally called a starter of the X-ray tube.

As mentioned above, this type of anode rotation drive device is
It is basically the same power supply as an induction motor, but it is much less efficient than a regular electric motor because the motor elements are in a vacuum and the rotor rotates, which requires high voltage insulation. In addition, since the stator with large inertia must be brought up to the standard rotation speed in a short period of about 0.5 to 3 seconds, high voltages of about 350 to 450 V and 2 to
It requires a large power of 6KVA.

FIG. 4 is a circuit diagram showing an example of a conventional anode rotation drive device, where 1 is an AC input and normally 100
~220V, 50 or 60Hz commercial AC power supply. This AC input is converted into DC by a rectifier circuit 2 made of a diode or the like, and then smoothed by a smoothing circuit 3 made of a capacitor to obtain DC. Reference numeral 4 denotes a low frequency transformer drive circuit which is configured as a bridge circuit using switch elements such as transistors, and is controlled by a control circuit 5. The low frequency transformer drive circuit 4 converts the input smoothed DC to a frequency required to rotate the anode, for example, in the case of high speed rotation.
It switches at 180Hz. The low frequency referred to here refers to several tens of kHz to 1 kHz, and the high frequency described later refers to 1 kHz to 1 MHz. This switching output is in the form of a rectangular wave, which is applied to the primary side of the low frequency transformer 6, and the boosted output obtained from the secondary side is sent to the main coil 9 of the stator 8 including the phase advance capacitor 7 and the sub coil. 10.

In this way, in the configuration shown in FIG. 4, after the frequency necessary to rotate the anode is obtained by the low frequency transformer drive circuit 4, a high voltage of about 350 to 450 V is obtained by the low frequency transformer 6. , 2~6KVA
In order to obtain a large amount of power, a large-capacity low-frequency transformer 6 is required, which poses a problem in that the device configuration becomes large and heavy.

(Problem to be solved by the invention) In this way, in the conventional technology, the voltage is increased after setting the desired frequency using a low-frequency transformer, which increases the size and weight of the device configuration. There was a problem with that.

Therefore, an object of the present invention is to provide an X
An object of the present invention is to provide an anode rotation drive device for a wire tube.

[Structure of the Invention] (Means for Solving the Problems) The present invention has a structure in which the following means are taken to solve the above problems and achieve the objects.
That is, the X-ray tube anode rotation drive device according to the present invention includes a rectifier circuit that converts AC input into DC and outputs it, and a high-frequency transformer drive that inputs the output of the rectifier circuit, converts it into high-frequency AC, and outputs it. circuit, a high-frequency transformer having a plurality of high-frequency transformer elements that input the output of this high-frequency transformer drive circuit to the primary side, convert it to a predetermined voltage, and output it from the secondary side, and smooth the high-frequency components in the output of this high-frequency transformer. The present invention is characterized by comprising a smoothing circuit that converts the output of the smoothing circuit into alternating current of a predetermined frequency and supplies it to an anode drive coil of an X-ray tube.

(Function) According to such a configuration, the input frequency is once converted into high-frequency alternating current by the high-frequency transformer drive circuit, and then the voltage is converted by the plurality of high-frequency transformer elements to generate the frequency necessary to rotate the anode. By setting the high frequency transformer element of the high frequency system,
Smoothing circuits and bridge circuits can be employed.

Furthermore, by configuring the high-frequency transformer that transforms the output of the high-frequency transformer drive circuit to have multiple high-frequency transformer elements, the capacity required for the high-frequency transformer can be distributed among the multiple high-frequency transformer elements, and each high-frequency transformer element The capacity can be reduced, and costs can be reduced.

(Embodiment) An embodiment of the anode rotation drive device for an X-ray tube according to the present invention will be described below with reference to FIG. 1, in which the same parts as in FIG. 4 are given the same reference numerals.

As shown in FIG. 1, the direct current smoothed by the smoothing circuit 3 is transferred to a high frequency transformer drive circuit 1 which forms a bridge circuit using switch elements such as transistors.
The alternating current that is input into the high-frequency transformer 1 and becomes a rectangular wave after being subjected to high-frequency switching by PWM (pulse width modulation) is input to the primary side of the high-frequency transformer 12. This high frequency transformer 12 boosts a rectangular waveform high frequency input and outputs it from its secondary side.The high frequency rectifier circuit 13 produces a rectangular waveform high frequency output as shown in FIG. With this circuit, a half-sine wave boosted DC output as shown in FIG. 2c from which high frequency components are removed is obtained. The half-wave of this boosted DC output is inverted in synchronization with the PWM period by a bridge circuit 16 made up of a switch element such as a transistor, and a sine wave output shown in FIG. 2d is obtained. 8 main coils 9 and sub-coils 10.

Note that the high frequency transformer drive circuit 11 and the bridge circuit 16 are controlled by a control circuit 17.

In this way, in the configuration shown in FIG.
The voltage is boosted at , and then the frequency is set to the level necessary to rotate the anode. However, the high-frequency transformer drive circuit 11 and subsequent parts are high-frequency systems, and the elements (components) used include high-frequency transformers, chiyoke coils, etc. That's a good thing. In general, high-frequency devices are smaller and lighter than low-frequency devices for the same capacity, so being able to use high-frequency components to obtain high power of 2 to 6 KVA means that the device configuration can be changed from the conventional device configuration. This means that it can be made smaller and lighter than the previous model.

Further, FIG. 2a shows the coil supply voltage waveform (point a) in FIG. 4, which is a rectangular wave. In this embodiment, as shown in FIG. 2d, the waveform is a sine wave (actually, it is close to a sine wave), so the induction motor can be driven efficiently.

Further, as shown in FIG. 3, one high frequency transformer 12 in FIG. 1 is replaced with four high frequency transformers 12a.
~12d (although there are two in the figure), and rectifier circuits 13a1, 13a2~13d are respectively installed.
1, 13d2 may be provided. According to this configuration, a plurality of inexpensive, small-capacity, high-frequency transformers are substituted for an expensive, large-capacity, high-frequency transformer, so that cost reduction can be realized. Also, 4
By independently providing high frequency transformer drive circuits on the primary sides of the two high frequency transformers 12a to 12d, the output voltage can be finely adjusted. In other words, high resolution of the output voltage can be achieved. Of course, four high frequency transformers 12a to 1
2d may be connected to one high frequency transformer drive circuit, and the number of installed high frequency transformers is not specified.

[Effects of the Invention] As described above, the present invention includes a rectifier circuit that converts AC input into DC and outputs it, and a high-frequency transformer drive circuit that inputs the output of the rectifier circuit, converts it into high-frequency AC, and outputs it. , a high-frequency transformer having a plurality of high-frequency transformer elements that input the output of this high-frequency transformer drive circuit to the primary side, convert it to a predetermined voltage, and output it from the secondary side; and a smoothing device that smooths the high-frequency components in the output of this high-frequency transformer. circuit and
It is equipped with a bridge circuit that converts the output of this smoothing circuit into alternating current at a predetermined frequency and supplies it to the anode drive coil of the X-ray tube.

According to this configuration, the input frequency is first converted into high-frequency alternating current by a high-frequency transformer drive circuit, and then the voltage is converted by multiple high-frequency transformer elements and set to the frequency necessary to rotate the anode. As a result, it is possible to use high-frequency transformer elements, smoothing circuits, and bridge circuits after the high-frequency transformer drive circuit that are smaller and lighter than low-frequency ones, making the device more compact than conventional equipment. It is possible to realize a reduction in size and weight.

Furthermore, by configuring the high-frequency transformer that transforms the output of the high-frequency transformer drive circuit to have multiple high-frequency transformer elements, the capacity required for the high-frequency transformer can be distributed among the multiple high-frequency transformer elements, and each high-frequency transformer element The capacity can be reduced, and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of an anode rotation drive device for an X-ray tube according to the present invention, FIG. 2 is an operation waveform diagram of the same embodiment, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a circuit diagram showing the structure of a conventional example. 1... AC input, 2... Rectifier circuit, 3... Smoothing circuit, 7... Phase advance capacitor, 8... Stator, 9
...Main coil, 10...Sub coil, 11...
...High frequency transformer drive circuit, 12, 12a, 12
d...High frequency transformer, 13, 13a1, 13a
2, 13d1, 13d2... Rectifier circuit, 14...
Chiyoke coil, 15... Capacitor, 16...
Bridge circuit, 17...control circuit.

Claims (1)

[Scope of Claims] 1. A rectifier circuit that converts AC input into DC and outputs it; A high-frequency transformer drive circuit that inputs the output of this rectifier circuit, converts it into high-frequency AC, and outputs it; This high-frequency transformer drive circuit A high-frequency transformer having a plurality of high-frequency transformer elements that inputs the output of the high-frequency transformer into the primary side, converts it to a predetermined voltage, and outputs it from the secondary side; a smoothing circuit that smoothes the high-frequency component in the output of the high-frequency transformer; and the smoothing circuit. An anode rotation drive device for an X-ray tube, comprising a bridge circuit that converts the output of the converter into alternating current at a predetermined frequency and supplies the output to an anode drive coil of the X-ray tube.