JPS63202897A - High voltage dc source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a high-voltage DC power supply device that supplies high voltage to a neutral particle injection device that generates high-speed neutral particles, and in particular, The present invention relates to a high-voltage DC power supply that absorbs the energy of floating static charges present in the high-voltage DC power supply.

(Prior art) A neutral particle injection device (hereinafter abbreviated as NBI) used in nuclear fusion experimental equipment ionizes hydrogen atoms, etc., accelerates these ions by applying a high DC voltage, and then High-speed neutral particles (
For example, hydrogen atoms) are generated.

FIG. 2 is a configuration diagram of a conventional high-voltage DC power supply device that supplies power to the NBI. In FIG. 2, 1 is a high-voltage DC power supply, and 2 is an ion source that serves as a load for the high-voltage DC power supply 1. Inside this ion source 2, an accelerating electrode 3a and a grounding electrode 3b are arranged at a predetermined interval. 1 power supply line 4a
, 4b to the "auxiliary side" and "-" side of the high voltage DC power supply l. Note that the "-" side power supply line 4b is connected to the ground. 5 converts the AC power supplied via the isolation transformer 6 into DC power with a voltage of about 10 to 200 V and a current of several kA, and supplies this power to the second power supply 1! This is a low-voltage, large-current DC power supply that is supplied via line 7 to an arc filament for ionizing hydrogen atoms and the like in ion #i2. Therefore, the feed line 7 is connected to the ion source 2.
They are provided in correspondence with the number of loads in the system, and the number may reach several dozen in some cases. This feeder line 7 sends low voltage and large current to the ion source 2, resulting in a voltage drop.
The cross-sectional area of each conductor is increased in consideration of heat generation. Note that the DC power supply 5 is connected to the power supply line 4a via a potential fixing line 8, and is fixed at the potential of the secondary side of the high voltage DC power supply 1. Therefore, the DC power supply 5 is used in a state where it is floating at a high voltage from the ground. In the isolation transformer 6, the high potential side winding 6a is connected to the DC source 5, and the low potential side winding 6a is connected to the DC source 5.
b is connected to an external AC power source. Reference numeral 9 indicates a housing of the insulating transformer 6, and a ground terminal 9a of this housing 9 is connected to the earth.

By the way, floating static charges exist in such devices. That is, they are a floating static charge 1o that the high potential winding 6a of the isolation transformer 6 has with respect to the ground, and a floating static charge 11 that the power supply line 4a has with respect to the ground. In addition, floating static charge 10. II is indicated with the symbol of a capacitor.

Therefore, when accelerating ions in the ion source 2,
A high voltage is applied between the accelerating electrode 3a and the ground electrode 3b by the high voltage DC power supply 1 to generate a strong electric field, and hydrogen ions and the like are accelerated by this strong electric field.

In order to generate a strong electric field in this way, these electrodes of 3m,
The spacing between electrodes 3b becomes narrower, and often the electrodes 3h, 3
A discharge phenomenon occurs between b. For this reason, conventionally, when a discharge phenomenon occurs, the power supply from the high voltage DC power supply 1 is
ec) It was stopped by order.

However, even if a discharge occurs and the power supply is stopped, the floating static charge 1
0.11, a short circuit current III flows as shown in FIG. 2, and most of this short circuit current is consumed as heat energy at the electrodes 3m and 3b. However, since the 3as3b is formed in a thin plate shape, the energy of a small amount of floating electrostatic charge (for example, several tens of joules to several 100 times ale)
But it gets damaged. Therefore, it has been desired to remove and absorb the slight stray electrostatic charge energy by some means.

FIG. 3 is a block diagram of a conventional high voltage DC power supply device provided with means for absorbing stray electrostatic charge energy.

Note that the same parts as in FIG. 2 are given the same reference numerals, and detailed explanation thereof will be omitted. In the device shown in FIG. 3, in order to reduce the short circuit current IB due to stray electrostatic charge energy, the nine magnetic bodies 20 are formed into a hollow cylinder with a predetermined thickness and the feed lines 4a and 7 are passed through the hollow parts. Further, a secondary winding 22 in which a resistor 21 is connected to the magnetic body 20 is provided. Then, the power supply line 4IL is connected via the secondary winding 22 and the magnetic body 20.

A transformer with a transformation ratio of 1:1 is formed with 7 as the primary winding.

Therefore, when a discharge occurs between the electrodes 3a and sb of the ion source 2, a short circuit current flows due to the floating static charge 10.11, but due to the dielectric action, the secondary winding 2
A current IR of the same magnitude as 2 flows. This results in a floating static charge of 10. Most of the energy of II will be consumed by resistor 21. However, this is the action of an ideal transformer, and is actually affected by the excitation current that generates the internal magnetic flux of the magnetic body 20. In other words, the excitation inductance of the magnetic body 20 is calculated by the initial voltage of the floating static charge. , the time when the voltage is applied between the poles of the magnetic body 20 is ΔT
, if the flowing excitation current is IL, ■. ×ΔT=LXI
, ...(1) holds true. Now, vo~100kV, ΔT~lμsec, L
j''W is 10μH, then equation (1) shows a large value.Therefore, current flows through the electrodes 3m and 3b induced by this exciting current, and this causes the electrode 3
h, 3b may be damaged.

(Problem to be solved by the invention) Therefore, in order to reduce the excitation current
) As can be seen from the equation, there is no choice but to increase the excitation inductance L or decrease the initial voltage v0 and time ΔT. However, since vo is related to the performance of NBI, it is impossible to reduce it. Further, since ΔT is also a constant determined in relation to other circuit constants, it is almost impossible to reduce it.

On the other hand, the excitation inductance L depends on the external dimensions of the magnetic body 20, and is particularly proportional to the overall length. Therefore, in order to reduce the excitation current LL, it is sufficient to increase the total length of the magnetic body 20. By the way, the total length of the magnetic body 20 currently used is about 1 to 2 m. On the other hand, the allowable current value of the short circuit current set in the ion source 2 is approximately several tens of OA. Therefore, in order to keep the current within this permissible value, the total length of the magnetic body 20 must be made about 10 times longer than the current length.

Because of this, the space in which the magnetic body 20 is installed must be increased. Furthermore, since many ferrite cores having good frequency characteristics in high ranges are used, there is also an economical problem.

On the other hand, a method of using a winding wire instead of the magnetic material 20 was also considered, but this would require several tens of lines such as the feeder line 7, where a large current flows and whose cross-sectional area is large, to pass through.
This is also economically problematic.

In any case, it is economically problematic and not compact.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a high voltage DC power supply device that is compact and economical and can absorb the energy of floating static charges.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a first power supply line between an acceleration electrode and a ground electrode of an ion source that accelerates ions to generate high-speed neutral particles. A high-voltage DC power supply that applies high voltage and a high current that is supplied via a second feeder to the ninth filament that converts the AC power supplied via the transformer into DC power and ionizes the atoms of the ion source. In a high voltage DC power supply device consisting of a DC power supply, an energy consuming element is provided between the ground and a closed loop circuit formed from a transformer, a large current power supply, first and second power supply lines, and an ion source. This is a high voltage DC power supply device that attempts to achieve the above object.

(Function) By providing such a means, when a discharge occurs between the accelerating electrode and the ground electrode, the transformer that supplies AC power to the large current DC power source, the large current DC power source, and the When a current due to stray static charges flows into the closed loop circuit formed by reaching the ion source through the second power supply line from this DC power supply and the first power supply line that supplies high voltage to the accelerating electrode from the high voltage DC power supply, this Current is dissipated in the energy consuming elements.

(Example) Hereinafter, an example of a high voltage DC power supply device according to the present invention will be described with reference to FIG. Note that the same parts as in FIG. 2 are given the same reference numerals, and detailed explanation thereof will be omitted. The high-voltage DC power supply shown in FIG. 1 connects the transformer 6 between the ground terminal 9a of the casing 9 and the earth as an energy consuming element in order to consume the energy of stray static charges. The configuration is such that they are connected via a resistor 30.

Note that the casing 9 of the transformer 6 is insulated from the ground with an insulator or the like.

Next, the function of the device configured as shown in FIG. 1, particularly in consuming stray electrostatic charge energy, will be explained. A first power supply line (a.

Accelerating electrode 3a and grounding electrode 3b of ion source 2 through 4b
When a high voltage is applied between the DC power supply 5 and the arc filament of the ion source 2 through the second power supply line 7, the ion source 2 ionizes, for example, hydrogen atoms. These ions are accelerated by the electrode 3a
A strong electric field generated between the hydrogen atoms and the ground electrode 3b accelerates the hydrogen atoms and causes them to collide with hydrogen atoms, generating high-speed neutral particles through charged particle exchange.

If a discharge occurs between the accelerating electrode 3a and the ground electrode 3b of the ion source 2 in such a state, the floating static charge 10
．． 11, transformer 6, DC power supply 5, power supply lines 4a and 7, ion source 2, ground and energy consumption resistor 3o
A short-circuit current flows through the closed loop circuit formed by However, this short circuit current I8 is consumed as a sinking force by this consuming resistor 3o. That is, floating static charge 10. Most of the energy of II will be consumed as heat. At this time, a voltage appears instantaneously across the energy consumption resistor 3°, and the potential of the casing 8 of the transformer 6 floats with respect to the ground; Since it is insulated with insulators, etc., it is not affected by this.

In this way, in this device, since the casing 9 of the transformer 6 and the earth are connected through the energy consumption resistor 3o, a discharge occurs between the accelerating electrode 3a and the grounding electrode 3b.
Even if the short-circuit current I8 flows due to the floating static charge 10.11, this current I8 is consumed (absorbed) as heat by the energy consumption resistor 30, and the accelerating electrode 3a and the grounding electrode 3b
and will no longer be damaged. Moreover, there is no need to install a magnetic body as in the conventional case, and there is no need to consider the influence of the excitation current of this magnetic body. therefore,
Its structure is simpler than that of the conventional one, and the energy consumption resistor 30 may be the same as the resistor 21 used in the device shown in FIG.

Note that the present invention is not limited to the above embodiment. For example, if the insulating transformer 6 has an electrostatic shield or a cross-contact prevention plate, the lead terminal of the electrostatic shield or cross-contact prevention plate can be connected to the ground terminal 9a of the casing 9 inside or outside the insulating transformer 6. Furthermore, this ground terminal 9a and the earth may be connected via an energy consumption resistor. With this configuration, not only the floating static charge 10.11, but also the energy of the floating static charge between the high potential winding 6a of the transformer 6 and the electrostatic shield, and the energy of the stray static charge between the high potential winding 6a and the contact prevention plate are reduced. It can also absorb the energy of stray static charges between '.

9. If the feeder lines 4a and 7 are covered with metal structures or plates, the above method will not work even if the ground terminals of these metal structures or plates are connected to the earth via an energy consumption resistor. The same effects as in the embodiment can be achieved.

Note that the present invention can be modified without departing from the spirit thereof.

[Effects of the Invention] According to the present invention, an energy/L/G consumption element is provided in a closed loop circuit in which a short-circuit current due to floating static charges flows when discharge occurs in the ion source. It is possible to provide a high-voltage DC power supply device that is compact and economical and can absorb the energy of

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the high voltage DC power supply device according to the present invention, Fig. 2 is a block diagram of a conventional device, and Fig. 3 is a block diagram showing a conventional device for absorbing the energy of stray static charges. It is a block diagram of a device. I...High voltage DC power supply, 2...Ion source, 3a...
Accelerating electrode, 3b...Grounding M, pole, 4m, 4b...Power supply, 5...DC power supply, 6...Isolation transformer, 7...
・Power supply line, 30...Resistance for energy consumption. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 3

Claims (1)

[Claims] A high-voltage DC power supply that applies a high voltage via a first power supply line between an acceleration electrode of an ion source that accelerates ions to generate high-speed neutral particles and a ground electrode, and AC power supplied via a transformer. a high-voltage DC power supply that converts the DC power into DC power and supplies the converted DC power to a filament for ionizing atoms of the ion source via a second power supply line, the transformer; An energy consuming element is provided between a closed loop circuit formed from a large current DC power source, the first and second power supply lines, and the ion source and the earth, and a discharge occurs between the accelerating electrode and the grounding electrode. A high-voltage DC power supply device characterized in that the energy consumption element consumes current due to floating static charges flowing through the closed loop circuit.