JPH0226159Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a power supply device that supplies power to an X-ray tube, and is particularly suitable for improving the X-ray tube voltage waveform that changes depending on the X-ray conditions (tube voltage and tube current). The present invention relates to an X-ray power supply device.

Figure 1 shows one circuit of a conventional X-ray power supply.
is a DC power supply, 2 is an inverter circuit, 3 is a voltage regulator (auto transformer) that adjusts and outputs the voltage of DC power supply 1, and 4 is a high voltage generator (including a rectifier)
5 is an X-ray tube that boosts the output voltage of the voltage regulator 3 at a constant ratio.

In the X-ray apparatus, the voltage applied to the X-ray tube 5 needs to be adjusted in the range of 20 kV to 150 kV depending on the X-ray conditions, for example. The configuration shown in Figure 1 uses a DC power supply 1 that supplies a stable voltage and an inverter circuit 2 that only performs DC/AC conversion without a voltage adjustment function to improve the tube voltage waveform. A voltage regulator 3 is required as a function to adjust the tube voltage within the above-mentioned range.

When, for example, square wave alternating current power is applied to the primary side of the autotransformer 3, the X-ray tube voltage will depend on the leakage inductance L of the autotransformer 3 and the high voltage generator 4.
, an oscillating current flows due to the stray capacitance C of the high-voltage cable, etc., the equivalent resistance R of the X-ray tube, etc.
The vibration waveform is as shown in . In such a configuration device, there is a drawback that when the X-ray conditions are variously changed, the tube voltage waveform differs under each condition. This is because, from the perspective of X-ray dose and radiation quality, it is preferable for the tube voltage waveform to be flat for a long time at a predetermined set voltage. A waveform with a short fixed period of time has the disadvantage that the X-ray dose is small and the radiation quality is soft.

The purpose of the present invention is to provide a power supply device that suppresses vibrations caused by leakage inductance of a transformer and stray capacitance of high-voltage cables, etc., and obtains a good X-ray tube voltage waveform under various X-ray conditions.

In this case, the leakage inductance of the transformer, the stray capacitance of the high-voltage cable, etc., and the equivalent resistance of the This is designed to suppress vibrations in the tube voltage, and even if the X-ray conditions (tube voltage/tube current) change, by switching the resistance, vibrations can be suppressed in the tube voltage waveform under any conditions. It is something that no longer occurs.

An embodiment of the X-ray power supply device according to the present invention is shown in FIG. In the figure, 6 is a resistance, 6a, 6b...
It consists of a plurality of resistors 6m, . . . , 6n having different resistance values. Circuits and devices that are otherwise numbered the same as in FIG. 1 represent the same circuits and devices. FIG. 3 will be explained.

When the brushes 3a and 3b of the autotransformer 3 are adjusted to a predetermined tube voltage and the inverter circuit 2 connected to the primary side of the autotransformer 3 is started, the autotransformer 3 is converted into an inverter. AC power of the same frequency as the frequency is supplied. A preset AC power is output to the secondary side of the autotransformer.
Oscillations in the tube voltage due to the leakage inductance of the transformer and the stray capacitance of the high voltage cable are suppressed through a resistor of 6 m selected to suit the X-ray conditions, and power is supplied to the high voltage generator 4. After boosting, the X-ray tube 5 second to
A tube voltage as shown in Figure b is applied. Then, by stopping the inverter circuit 2, the X-ray tube 5
The power supply to the unit is interrupted. Further, when the X-ray conditions change, the value of the resistor 6m is changed to a resistance suitable for the conditions, so that the X-ray tube voltage always has a good waveform.

According to an embodiment of the present invention, when the tube voltage oscillates due to the leakage inductance of the transformer, the stray capacitance of the high voltage cable, etc., and the equivalent resistance of the X-ray tube, the By setting the resistance to an appropriate value, vibrations in the tube voltage can be suppressed and a good tube voltage waveform can be obtained. Therefore, when the X-ray conditions change, switching to a resistor having a resistance value suitable for the conditions has the effect of ensuring that the tube voltage always has a good waveform.

FIG. 4 shows another embodiment of the present invention, which differs from FIG. 3 in that the resistor is inserted at a position connected to the primary side of the autotransformer 3. This embodiment further includes an inverter circuit 2. This has the effect of suppressing vibrations in the entire circuit.

According to the present invention, it is possible to obtain an X-ray tube voltage waveform with a long flat time at a set tube voltage value with suppressed vibrations, and even when X-ray conditions change, the tube voltage waveform remains stable. An X-ray power supply can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional X-ray power supply using an inverter, Fig. 2 is an explanatory diagram of an X-ray tube voltage waveform, and Fig. 3 is a block diagram of an embodiment of the X-ray power supply of the present invention. , FIG. 4 shows a configuration diagram of another embodiment of the X-ray power supply device of the present invention. 1...DC power supply, 2...Inverter circuit, 3...
...Voltage regulator, 4...High voltage generator, 5...X-ray tube, 6...Resistor.

Claims (1)

[Scope of utility model registration request] A DC power supply, an inverter that converts the DC voltage from the DC power supply into AC voltage, a voltage regulator that adjusts and outputs the output voltage of the inverter, and boosts the output voltage from the voltage regulator and supplies it to the X-ray tube. In an X-ray power supply device comprising a high voltage generator that
An X-ray power supply device characterized in that a resistor whose resistance value can be appropriately set according to the tube voltage and tube current applied to the ray tube is added in series to the input side or output side of a voltage regulator.