JP7082723B1 - Medical X-ray power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and highly efficient medical X-ray power supply device capable of controlling AC power whose rated output greatly differs depending on a mode. A medical X-ray power supply device 301 according to the present invention is an X-ray output from an X-ray tube EDT, and powers an X-ray device having a fluoroscopic mode for seeing through a subject and a photographing mode for photographing the subject. A medical X-ray power supply that supplies an inverter inv that outputs alternating current with different frequencies in the fluoroscopic mode and imaging mode, and an X-ray tube EDT that connects the alternating current input to the primary side to the secondary side. The transformer Tr is provided with a transformer Tr that outputs to, and a resonance circuit RC that connects the inverter inv and the primary side of the transformer Tr. It is characterized by having a switch SW for selecting the path P1 in the P2 and the fluoroscopic mode and selecting the path P2 in the photographing mode. [Selection diagram] Fig. 1

Description

The present disclosure relates to a medical X-ray power supply that supplies DC power to an X-ray tube.

Medical devices that use X-rays include devices that realize both an imaging mode such as X-ray imaging and a fluoroscopic mode such as catheterization. Here, in the shooting mode, although it is a short time (for example, 0.1 second), a large rated output (for example, 80 kW to 100 kW) is required, and in the fluoroscopic mode, a small rated output (for example, 25 W to 1 kW) is required. It is necessary to output continuously. In this way, when trying to realize both the imaging mode (high output power mode) and the fluoroscopic mode (small output power mode) with one medical device, the rated output differs by 4000 times, and the alternating current supplied to the device. Power control is difficult.

It is known to utilize resonance between a capacitor and an inductance for controlling AC power when the rated output differs greatly depending on the mode (see, for example, FIG. 2 of Patent Document 1). By moving the output frequency of the inverter closer to the resonance frequency, it becomes a large output power mode, and conversely, by moving the output frequency of the inverter away from the resonance frequency, it becomes a small output power mode.

Further, in Patent Document 1, the output frequency of the inverter in the low output power mode is set higher than the audible frequency range in order to solve the problem that noise occurs when the output frequency of the inverter drops to the audible frequency range in the low output power mode. It is also disclosed that it is realized by fixing and lowering the DC voltage input to the inverter.

Japanese Unexamined Patent Publication No. 06-310295

A power supply device such as Patent Document 1 has a small output by using a thyristor to reduce the DC voltage input to the inverter (addition of a thyristor circuit) and controlling the pulse width of the inverter (generation of switching loss). Since the electric power is realized, there is a problem that it is difficult to reduce the size of the device and improve the efficiency at the time of small output power.

Therefore, in order to solve the above problems, it is an object of the present invention to provide a compact and highly efficient medical X-ray power supply device capable of controlling AC power whose rated output greatly differs depending on the mode. ..

In order to achieve the above object, the medical X-ray power supply device according to the present invention has a resonance circuit for a small output power mode and a resonance circuit for a large output power mode, and the output frequency of the inverter is different for each mode. And, it was decided to switch to the resonance circuit of each mode with a switch.

Specifically, the medical X-ray power supply device according to the present invention uses X-rays output from an X-ray tube to supply electric power to an X-ray device having a fluoroscopic mode for seeing through the subject and a photographing mode for photographing the subject. It is a medical X-ray power supply to be supplied.
An inverter that outputs alternating current with different frequencies in the fluoroscopic mode and the shooting mode,
A transformer that outputs the alternating current input to the primary side to the X-ray tube connected to the secondary side, and
A resonant circuit connecting the inverter and the primary side of the transformer,
Equipped with
The resonance circuit selects a first path that resonates at the frequency of the fluoroscopic mode, a second path that resonates at the frequency of the imaging mode, and the first path that resonates at the frequency of the fluoroscopic mode, and the imaging mode. It is characterized by having a switch for selecting the second route at the time of.

The medical X-ray power supply device includes a resonance circuit (first path) for a small output power mode. By resonating the resonance circuit for the small output power mode in parallel, it is possible to reduce the DC voltage input to the inverter by using a thyristor and to realize a small output power without controlling the pulse width of the inverter. That is, the thyristor circuit is not required, the size can be reduced, and the conversion efficiency at the time of small output power can be improved. By setting the resonance frequency of the resonance circuit for the small output power mode above the audible frequency range, the problem of noise can be solved.

Therefore, the present invention can provide a compact and highly efficient medical X-ray power supply device capable of controlling AC power such that the rated output greatly differs depending on the mode.

The present invention can provide a compact and highly efficient medical X-ray power supply device capable of controlling AC power such that the rated output greatly differs depending on the mode.

It is a figure explaining the medical X-ray power supply device which concerns on this invention. It is a figure explaining the medical X-ray power supply device which concerns on this invention. It is a figure explaining the resonance circuit of an inductance means and a capacitor. It is a figure explaining the medical X-ray power supply device which concerns on this invention. It is a figure explaining the medical X-ray power supply device which concerns on this invention. It is a figure explaining the medical X-ray power supply device which concerns on this invention. It is a figure explaining the medical X-ray power supply device which concerns on this invention. It is a figure explaining the relationship between the switching frequency and the output mode of the medical X-ray power supply device which concerns on this invention.

An embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and the drawings, the components having the same reference numerals shall indicate the same components.

[Embodiment 1]
FIG. 1 is a diagram illustrating a medical X-ray power supply device 301 of the present embodiment. The medical X-ray power supply device 301 is an X-ray output from the X-ray tube EDT, and is a medical X-ray power supply that supplies power to an X-ray device having a fluoroscopic mode for seeing through the subject and a photographing mode for photographing the subject. And,
Inverter inv that outputs alternating current with different frequencies in fluoroscopy mode and shooting mode,
A transformer Tr that outputs the alternating current input to the primary side to the X-ray tube EDT connected to the secondary side,
Resonance circuit RC that connects the inverter inv and the primary side of the transformer Tr,
Equipped with
The resonant circuit RC selects the first path P1 that resonates at the frequency f1 in the fluoroscopic mode, the _second path P2 that resonates at the frequency f2 in the photographing mode, and the _first path P1 that resonates at the frequency f2 in the fluoroscopic mode. It is characterized by having a switch SW for selecting the second path P2 in the shooting mode.

The first path P1 of the present embodiment has a parallel circuit PC in which the first inductance means L1, the first capacitor C1 and the second inductance means L2 are parallel to each other, and the first inductance means L1 and the parallel circuit PC are in series. The _first capacitor C1 and the second inductance means L2 resonate in parallel at the frequency f1 in the see-through mode.
In the second path P2 of the present embodiment, the third inductance means L3 and the second capacitor C2 are connected in series, and the third inductance means L3 and the _second capacitor C2 resonate in series at the frequency f2 in the photographing mode. It is characterized by doing.

In FIG. 1, the switch SW is composed of a switch SW1 arranged in the first path P1 and a switch SW2 arranged in the second path P2, but the switch SW is composed of the first path P1 and the second path P1. It may be one switch that exclusively selects the path P2 of.

Here, the difference between series resonance and parallel resonance will be described with reference to FIG. FIG. 3A is a diagram illustrating a series resonant circuit in which the inductance means L and the capacitor C are connected in series. When the power supply V outputs an alternating current having a resonance frequency _f0 of the inductance means L and the capacitor C, the series resonance circuit appears to be short-circuited when viewed from the power supply V (FIG. 3 (A2)).

On the other hand, FIG. 3B1 is a diagram illustrating a parallel resonant circuit in which the inductance means L and the capacitor C are connected in parallel. When the power supply V outputs an alternating current having a resonance frequency _f0 of the inductance means L and the capacitor C, the parallel resonance circuit seems to be released from the power supply V (FIG. 3 (B2)).

The resonance circuit RC of the medical X-ray power supply device 301 utilizes the operation of such series resonance and parallel resonance. The resonance frequency of the _first path P1 is f1. The resonance frequency of the _second path P2 is f2. Here, f ₁ ≠ f ₂ .

When the switching frequency of the inverter inv is f ₁ , the frequency of the alternating current output by the inverter inv is f ₁ , and the first path P1 is selected by the switch SW (SW1 is turned on and SW2 is turned off), the first path P1 is in parallel. It resonates and becomes an open state as shown in FIG. 3 (B2). That is, the equivalent circuit of the medical X-ray power supply device 301 when the switching frequency of the inverter inv is f ₁ is as shown in FIG. Since the impedance from the inverter inv to the transformer Tr is increased, the inverter inv can supply a small amount of electric power to the X-ray tube EDT.

On the other hand, when the switching frequency of the inverter inv is f2 and the frequency of the alternating current output by the inverter inv is f2 and the _second path P2 is selected by the switch SW (SW1 is turned off and SW2 is turned on), the _second path P2 is selected. Resonates in series, resulting in a short-circuit state as shown in FIG. 3 (A2). That is, the equivalent circuit of the medical X-ray power supply device 301 when the switching frequency of the inverter inv is f ₂ is as shown in FIG. Since the impedance from the inverter inv to the transformer Tr is lowered, the inverter inv can supply a large amount of electric power to the X-ray tube EDT.

That is, in the perspective mode, the switch SW selects the first path P1, the inverter inv switches at _a frequency f1 such that the capacitor C1 and the second inductance means L2 are in a resonance state, and in the photographing mode, the switch SW is switched. Selects the _second path P2, and the inverter inv switches at a frequency f2 such that the capacitor C2 and the third inductance means L3 are in a resonance state. In this way, the medical X-ray power supply device 301 is rated on the secondary side of the transformer Tr by switching the switching frequency (output AC frequency f ₁ / f ₂ ) and the path (P1 / P 2) of the inverter inv. Switch the output.

By switching the switching frequency of the inverter inv and the switch SW in this way, the medical X-ray power supply device 301 can change the impedance of the resonance circuit RC and greatly change the output power.

[Embodiment 2]
FIG. 2 is a diagram illustrating the medical X-ray power supply device 302 of the present embodiment. The medical X-ray power supply device 302 has a different circuit configuration of the resonance circuit RC from the medical X-ray power supply device 301 of FIG. That is, the resonance circuit RC of the medical X-ray power supply device 302 has a first inductance means L1 shared by the first path P1 and the second path P2.
The first path P1 has a parallel circuit PC in which the first capacitor C1 and the second inductance means L2 are parallel to each other, and is configured such that the first inductance means L1 and the parallel circuit PC are connected in series, and is transparent. It is characterized in that the _first capacitor C1 and the second inductance means L2 resonate in parallel at the frequency f1 of the mode.
The second path P2 has a second capacitor C2, is configured so that the first inductance means L1 and the _second capacitor are connected in series, and the first inductance means L1 and the first inductance means L1 at the frequency f2 in the photographing mode. The feature is that the two capacitors C2 resonate in series.

Since the medical X-ray power supply device 302 shares the first inductance means L1 between the first path P1 and the second path P2, the number of inductance means is increased with respect to the medical X-ray power supply device 301 of FIG. It can be reduced and made smaller.

As in the first embodiment, the switch SW may be one switch that exclusively selects the first path P1 and the second path P2.

The resonance circuit RC of the medical X-ray power supply device 302 also utilizes the operations of series resonance and parallel resonance as described with reference to FIG. The resonance frequency of the _first path P1 is f1. The resonance frequency of the _second path P2 is f2. Here, f ₁ ≠ f ₂ .

When the switching frequency of the inverter inv is f ₁ , the frequency of the alternating current output by the inverter inv is f ₁ , and the first path P1 is selected by the switch SW (SW1 is turned on and SW2 is turned off), the first path P1 is in parallel. It resonates and becomes an open state as shown in FIG. 3 (B2). That is, the equivalent circuit of the medical X-ray power supply device 302 when the switching frequency of the inverter inv is f ₁ is as shown in FIG. Since the impedance from the inverter inv to the transformer Tr is increased, the inverter inv can supply a small amount of electric power to the X-ray tube EDT.

On the other hand, when the switching frequency of the inverter inv is f2 and the frequency of the alternating current output by the inverter inv is f2 and the _second path P2 is selected by the switch SW (SW1 is turned off and SW2 is turned on), the _second path P2 is selected. Resonates in series, resulting in a short-circuit state as shown in FIG. 3 (A2). That is, the equivalent circuit of the medical X-ray power supply device 302 when the switching frequency of the inverter inv is f ₂ is as shown in FIG. Since the impedance from the inverter inv to the transformer Tr is lowered, the inverter inv can supply a large amount of electric power to the X-ray tube EDT.

That is, in the perspective mode, the switch SW selects the first path P1, the inverter inv switches at _a frequency f1 such that the capacitor C1 and the second inductance means L2 are in a resonance state, and in the photographing mode, the switch SW is switched. Selects the _second path P2, and the inverter inv switches at a frequency f2 such that the capacitor C2 and the first inductance means L1 are in a resonance state. In this way, the medical X-ray power supply device 302 is rated on the secondary side of the transformer Tr by switching the switching frequency (output AC frequency f ₁ / f ₂ ) and the path (P1 / P 2) of the inverter inv. Switch the output.

By switching the switching frequency of the inverter inv and the switch SW in this way, the medical X-ray power supply device 302 changes the impedance of the resonance circuit RC, and the output power can be significantly different.

(Example)
This embodiment is a specific example of the medical X-ray power supply device 302 of FIG. As described above, a medical device using X-rays has a fluoroscopic mode having a small rated output (for example, 25 W to 1 kW) and an imaging mode having a large rated output (for example, 80 kW to 100 kW).

The first inductance means L1 is l ₁ [H],
The second inductance means L2 is l ₂ [H],
The capacitor C1 is c ₁ [F]
Capacitor C2 is c ₂ [F]
And. FIG. 8A shows the relationship between the rated output of the medical X-ray power supply device and the switching frequency at this time.

ｆ_１で第１の経路Ｐ１のインピーダンス計算を行うと誘導性回路（例えば、インダクタンスｌ_ｘ［Ｈ］）で高インピーダンスとなり、医療用Ｘ線電源装置３０２はＸ線管球ＥＤＴに供給する出力を絞ることができる。このため、医療装置を透視モードで動作させることができる。 FIG. 8B shows an equivalent circuit of the medical X-ray power supply device 302 when the first path P1 is selected by the switch SW and the switching frequency of the inverter inv is set to the resonance frequency f ₁ kHz of the first path P1. Is. It should be noted that f ₁ satisfies the following equation and is about 15 kHz to 50 kHz.

When the impedance calculation of the first path P1 is performed with f ₁ , the impedance becomes high in the inductive circuit (for example, inductance l _x [H]), and the medical X-ray power supply device 302 outputs the output supplied to the X-ray tube EDT. Can be squeezed. Therefore, the medical device can be operated in the fluoroscopic mode.

ｆ_２で第２の経路Ｐ２のインピーダンス計算を行うと容量性回路（例えば、容量ｃ_ｘ［Ｆ］）で低インピーダンスとなり、医療用Ｘ線電源装置３０２は高出力をＸ線管球ＥＤＴに供給できる。このため、医療装置を撮影モードで動作させることができる。 FIG. 8C shows an equivalent circuit of the medical X-ray power supply device 302 when the second path P2 is selected by the switch SW and the switching frequency of the inverter inv is set to the resonance frequency f2 kHz of the _second path P2. Is. It should be noted that f ₂ satisfies the following equation and is about 50 kHz to 120 kHz.

When the impedance calculation of the second path P2 is performed with f ₂ , the impedance becomes low in the capacitive circuit (for example, the capacitance c _x [F]), and the medical X-ray power supply device 302 supplies a high output to the X-ray tube EDT. can. Therefore, the medical device can be operated in the photographing mode.

Output control is performed by using a resonance circuit RC having two paths with different resonance frequencies, selecting one path with the switch SW, and appropriately selecting the switching frequency of the inverter inv for each of the shooting mode and the see-through mode. Is possible. That is, the medical X-ray power supply device according to the present invention can support an operation mode in which the rated output differs by 4000 times.

The "resonance frequency" means the following.
In an actual medical X-ray power supply device, the resonance frequency is calculated based on the design values of the capacitor and the inductance means to control the switching frequency of the inverter inv. However, the actual capacitance of the capacitor and the actual inductance of the inductance means may deviate from the design value due to manufacturing errors and the like. For example, the error is 0 to ± 20% in the case of a capacitor and 0 to ± 15% in the case of an inductance means. Further, the resonant circuit RC itself and the transformer Tr also have capacitance and inductance components. Therefore, the resonance frequency calculated from the design value does not always match the resonance point (resonance frequency f1 or f2) of the _first path P1 or the _second path P2. Therefore, the "resonant frequency" includes a "frequency near the resonance frequency".
It should be noted that the medical X-ray power supply device may be operated in advance to measure the resonance points of the first path P1 and the second path P2, and the switching frequency of the inverter inv may be controlled at that frequency. ..

E: DC power supply inductance: Inverter SW, SW1, SW2: Switch Tr: Transformer RF: Rectification circuit EDT: X-ray tube RC: Resonance circuit P1: First path P2: Second path C1: First capacitor C2: 2nd capacitor L1: 1st inductance means L2: 2nd inductance means L3: 3rd inductance means PC: Parallel circuit

Claims (3)

A medical X-ray power supply that supplies electric power to an X-ray device having a fluoroscopic mode for seeing through a subject and a photographing mode for photographing the subject with X-rays output from an X-ray tube.
An inverter that outputs alternating current with different frequencies in the fluoroscopic mode and the shooting mode,
A transformer that outputs the alternating current input to the primary side to the X-ray tube connected to the secondary side, and
A resonant circuit connecting the inverter and the primary side of the transformer,
Equipped with
The resonance circuit selects a first path that resonates at the frequency of the fluoroscopic mode, a second path that resonates at the frequency of the imaging mode, and the first path that resonates at the frequency of the fluoroscopic mode, and the imaging mode. A medical X-ray power source comprising a switch for selecting the second route at the time of. The first path has a first inductance means and a parallel circuit in which the first capacitor and the second inductance means are parallel to each other, and the first inductance means and the parallel circuit are connected in series, and the see-through mode. The first capacitor and the second inductance means resonate in parallel at the frequency of.
The second path is characterized in that the third inductance means and the second capacitor are connected in series, and the third inductance means and the second capacitor resonate in series at the frequency of the photographing mode. Medical X-ray power supply described in. The resonant circuit has a first inductance means shared by the first path and the second path.
The first path has a parallel circuit in which the first capacitor and the second inductance means are parallel to each other, the first inductance means and the parallel circuit are connected in series, and the first is at the frequency of the perspective mode. The feature is that the capacitor and the second inductance means resonate in parallel.
The second path has a second capacitor, the first inductance means and the second capacitor are connected in series, and the first inductance means and the second capacitor are connected in series at the frequency of the shooting mode. The medical X-ray power supply according to claim 1, wherein the capacitor resonates.

Images