JPH0234435B2 - DAIDENRYUHODENSUITSUCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a high current discharge switch.

Large current discharge switches for capacitors are classified into high pressure discharge switches for capacitors and low pressure discharge switches for capacitors, and the large current discharge switch of the present invention belongs to the high pressure discharge switch for capacitors.

Conventionally used high-pressure discharge switches for capacitors (generally called pressurized type) can be roughly divided into Triggertron type pressurized discharge switches for capacitor discharge (hereinafter referred to as Triggertron type discharge switches) and Field Distortion type. Pressure type discharge switch for capacitor discharge (hereinafter referred to as electric field distortion type discharge switch) 2
Divided into types.

An example of a circuit diagram using a conventional triggertron type (a spark gap having a trigger pin embedded in one of the main electrodes is called a triggertron) discharge switch is shown in FIG. In Figure 4, C is the main capacitor, _T1 is the trigger pin, L is the load (load coil), _TC1 is the trigger circuit, TDCS is the triggertron type discharge switch, Vc is the capacitor charging voltage, Vt
is the trigger voltage.

The triggertron type discharge switch TDCS applies a fast-rising trigger voltage Vt to the main discharge electrode on the side to which the main capacitor C is not connected to break down the insulation between the main discharge electrodes.

A portion of the trigger voltage Vt is also applied to the load L until the insulation between the main discharge electrodes is broken. In general, discharge characteristics are good when the voltage polarity is different between the capacitor charging voltage Vc and the trigger voltage Vt.

Next, an example of a circuit diagram using a conventional electric field distortion type discharge switch is shown in FIG. In FIG. 5, the explanations of the same reference numerals as those in FIG. 4 will be omitted. T ₂ is a trigger electrode, TC ₂ is a trigger circuit, and EDCS is an electrostrictive discharge switch.

The electric field distortion type discharge switch EDCS is provided with a trigger electrode _T2 as a third electrode between the main discharge electrodes, applies a fast-rising trigger voltage Vt to the trigger electrode _T2 , and applies a fast-rising trigger voltage Vt to the trigger electrode T2. A discharge is caused between the discharge electrode and the trigger electrode _T2 , and dielectric breakdown between the main discharge electrodes is subsequently induced. There are various shapes of the main discharge electrode and the trigger electrode _T2 , as shown in FIG. Trigger electrode T ₂ is connected to a resistive voltage divider, CR, in order to have an intermediate potential between the main discharge electrodes.
Share the voltage using a voltage divider such as a voltage divider. In general, discharge characteristics are good when the voltage polarity is different between the capacitor charging voltage Vc and the trigger voltage Vt.

When simultaneously charging and discharging a large number of high-current switches for capacitors, a major problem is the self-destructive discharge of the switches that occurs while charging the capacitors. Compared to the DC short-time breakdown voltage between the electrodes at the initial stage of switch manufacture (when no large current discharge has been performed), after several large current discharges, there is an imbalance due to damage to the electrode surface. The breakdown voltage is accidentally lowered by the electric field or by dust from molten electrode metal, causing irregular discharge while charging the capacitor. This is called the switch's self-destruction phenomenon.

In order to prevent self-destructive discharge of a discharge switch, applying excessive pressure so that the DC short-time breakdown voltage becomes large compared to the working voltage or making the electrode gap extremely wide is a method of This makes the switch uneconomical and requires a high trigger voltage to operate the switch. That is, it is important to optimally select the limit that will not cause self-destructive discharge and the trigger voltage necessary for operation.

In the case of the conventionally used triggertron type discharge switch, a trigger pin _T1 is provided on the main discharge electrode on the side where the main capacitor C is not connected, and it is designed to apply a trigger voltage Vt of the opposite polarity to the capacitor charging voltage Vc. However, as shown in Figure 7, the trigger pin is connected to the main discharge electrode on the side where the main capacitor C is connected.
When T ₁ is provided and the trigger voltage Vt is simply applied,
The trigger voltage Vt is absorbed by the main capacitor C, making it difficult to break down the insulation between the main discharge electrodes.

In addition, in the case of conventionally used electric field distortion type discharge switches, the discharge operation was uncertain when processing at a pressure corresponding to a DC short-time breakdown voltage that is twice the capacitor charging voltage. That is, there was a drawback that even if a trigger pulse was applied, the discharge sometimes did not occur.

The present invention eliminates the above-mentioned drawbacks, and is characterized in that a ferrite core is provided between the capacitor-side discharge electrode, which is the main discharge electrode of the discharge switch, and the main capacitor, and the trigger voltage is shared by the inductance created by the ferrite core. The present invention aims to provide a high-current discharge switch with a high current density.

Hereinafter, the present invention will be explained with reference to FIGS. 1 to 3.

Fig. 1 is a cross-sectional view of an embodiment of the large current discharge switch of the present invention, and Fig. 2 is a circuit diagram when the large current discharge switch of the present invention shown in Fig. 1 is connected to a capacitor discharge circuit. It constitutes a discharge switch.

First, in the circuit diagram _shown in Figure 2, _C1 is the main capacitor, C2 is the trigger capacitor, _G1 is the discharge switch gap, _G2 is the spark irradiation gap, _G3 is the trigger switch, R is the spark irradiation resistor, Fe is the ferrite core, L is the load, 1 is the discharge electrode on the capacitor side of the discharge switch, 2 is the discharge electrode on the load side of the discharge switch, 3 is the trigger pin, 19 is the coaxial cable on the capacitor side, 20 is the output side coaxial cable, 21 is the trigger It is a coaxial cable.

Next, in the part surrounded by the dotted line in the circuit of FIG. 2, that is, in FIG. The lower metal lid plate 7 is provided with an air exhaust hole 6a, and 7 is an insulating cylinder to which the trigger input terminal 4 is fixed.The upper end is attached to the upper metal lid plate 5 and the lower end is attached to the lower metal lid plate 6 through packing. There is. Reference numeral 8 denotes a conductor pipe, the upper end of which is fixed to the upper metal cover plate 5, and the lower end fixed to the capacitor side discharge electrode 1, respectively. In addition, the load side discharge electrode 2 facing the capacitor side discharge electrode 1 has a lower metal cover plate 6.
is fixed to. Reference numeral 9 denotes an ignition plug, which is fixed to the capacitor-side discharge electrode 1 and disposed within the conductor pipe 8, and a trigger pin 3 is provided within the ignition plug 9. The trigger pin 3 and the trigger input terminal 4 are connected by a conductive wire 10. One end of the spark irradiation resistor R is connected to the trigger input terminal 4, and the other end is connected to the upper metal cover plate 5. Reference numeral 11 denotes a ferrite penetrating conductor pipe, the lower end of which is fixed to the upper metal cover plate 5. Reference numeral 12 denotes a conductor pipe outer insulator such as a heat-shrinkable tube provided on the outer circumference of the conductor pipe 11, and a ferrite core Fe is provided on the outer circumference of the conductor pipe outer insulator 12.
A plurality of them are stacked up with an interlayer insulating film 13 interposed therebetween, and a fastener 15 is brought into contact with the upper and lower ends of the sheet through rubber sheets 14a and 14b for size adjustment and insulating, and the bolts and nuts 16 are tightened and fixed. Reference numeral 17 denotes a shield-cum-high-voltage plate, which is surrounded by a film insulator 18 surrounding the shield-cum-high-voltage plate. The shield/high voltage plate 17 is connected to the core wire 19a of the capacitor side coaxial cable 19, and the lower metal cover plate 6 is connected to the core wire 20a of the output side coaxial cable 20, respectively.

The large current discharge switch of the present invention is constructed as described above.

The large current discharge switch of the present invention has an upper metal cover plate 5.
Air is inserted through the air insertion hole 5a into the airtight container formed by the lower metal lid plate 6 and the insulating cylinder 7, and the pressure inside the airtight container is increased to generate a discharge in the discharge switch gap _G1 , and the pressure is maintained. After discharge, air is discharged from the air discharge hole 6a and air is inserted from the air insertion hole 5a. That is, the air in the sealed container is replaced when the discharge switch is used.

Next, one embodiment will be described. As shown in FIG. 3, the short-time breakdown characteristic of the discharge switch gap _G1 against the applied pressure is V=19P+23. In FIG. 3, indicates the self-destruction voltage characteristic, and indicates the actual operating voltage versus pressure characteristic. This discharge switch has a maximum working voltage of
When used at 40kV, the DC short-time breakdown voltage is
Pressurize at a pressure corresponding to 118kV (40kV x 2.95),
By replacing the pressurized gas (dry air) inside the discharge switch while maintaining the pressure at each discharge, a non-self-destructing gap can be created.

The relationship between the capacitor charging voltage V and the pressurizing pressure P is set as P=2.95V-23/19.

Main capacitor to discharge the discharge switch
Apply a trigger voltage with the same polarity as the charging polarity of C ₁ to trigger pin 3. The magnitude of the trigger voltage is (DC short-time breakdown voltage 118kV - capacitor charging voltage)
(40kV = 78kV) It is necessary to exceed 78kV.
When this trigger voltage is applied to trigger pin 3,
The spark irradiation gap is 10 to 20 kV, and the spark irradiation resistor R is short-circuited. The trigger voltage shared by the ferrite core Fe is L _F di/dt (L _F : inductance of the ferrite core Fe, i: trigger current), and its value changes as the ferrite core Fe is excited, but at the initial stage of the trigger, the trigger voltage It shares most of the voltage. The discharge switch is discharged due to an overvoltage that exceeds DC breakdown for a short time while exciting the discharge switch gap _G1 generated by the spark irradiation.

A discharge switch according to an embodiment of the present invention has a short-time DC breakdown voltage vs. pressure characteristic between electrodes of V=19P+23.
The actual operating voltage (capacitor charging voltage) is set to 1/2.95 for the same pressure (i.e., P =
2.95Vc−23/19Vc is the capacitor charging voltage), Vc=40kV, P=5Kg/cm ²・G, trigger voltage
At 80kV, the discharge variation was less than 50ns, and good characteristics were obtained. In addition, the voltage range that can operate with discharge variation of 50ns or less is 4~
At 40kV, we were able to significantly lower the minimum operating voltage compared to existing switches.

As mentioned above, the large current discharge switch of the present invention has a DC short-time breakdown voltage between the discharge electrodes/actual operating voltage=2
In the above manner, when a trigger voltage is applied to the discharge electrode 1 on the capacitor side, a spark is discharged at the spark irradiation interval 〓G ₂ provided on the discharge electrode 1, and the spark irradiation interval 〓G ₂ is short-circuited, resulting in a steep rise. At the rising part of the trigger voltage with rising characteristics, the main capacitor C ₁
The impedance of the trigger capacitor C ₂ is small, the surge impedance Z ₀ of the trigger coaxial cable 21, and the inductance L _F of the ferrite core Fe.
can be ignored. In other words, the trigger voltage is the surge impedance of the trigger coaxial cable 21 Z ₀
The partial pressure will be divided by the inductance L _F of the ferrite core Fe. Normally, the surge impedance Z ₀ of the trigger coaxial cable 21 is about 25 to 100Ω, and most of the trigger voltage is shared by the inductance L _F of the ferrite core Fe. Therefore, the inductance L _F created by the ferrite core Fe is
Since the trigger voltage rises in a short time due to the existence _of
In a short time until Fe saturates, the charging voltage of the capacitor + the shared voltage of the ferrite core is set to be higher than the DC short-time breakdown voltage of the discharge switch gap G ₁ , and the insulation of the discharge switch gap G ₁ is broken and discharged. By simply replacing the air inside the sealed container of the switch while maintaining its pressure, it is possible to discharge without self-destructive discharge. It has the effect of eliminating uneconomical costs, and has great industrial and practical value.

[Brief explanation of drawings]

Fig. 1 is a sectional view of one embodiment of the large current discharge switch of the present invention, Fig. 2 is a circuit diagram when the large current discharge switch of the present invention shown in Fig. 1 is connected to a capacitor discharge circuit, and Fig. 3 is a sectional view of an embodiment of the large current discharge switch of the present invention. Fig. 4 is a circuit diagram of an example using a pressurized discharge switch for discharging a conventional triggertron type capacitor; Fig. ₅ is a diagram of the conventional electric field strain Figure 6 is a schematic diagram showing the shapes of the main discharge electrode and trigger electrode of a conventional pressure type discharge switch for electric field distortion type capacitor discharge. In the case of a disc-shaped trigger electrode, B is a bar-shaped trigger electrode, C is a perforated disc-shaped trigger electrode, and Figure 7 shows a conventional triggertron type capacitor discharge pressurization with a triggertron type on the main capacitor side. FIG. 7 is a circuit diagram of another example using a type discharge switch. C ₁ : Main capacitor, C ₂ : Trigger capacitor,
G ₁ : Discharge switch gap, G ₂ : Spark irradiation gap,
_G3 : Trigger switch, R: Spark irradiation resistor,
Fe: Ferrite core, L: Load, 1: Discharge electrode on the capacitor side of the discharge switch, 2: Discharge electrode on the load side of the discharge switch, 5: Upper metal cover plate, 5a: Air insertion hole, 6: Lower metal cover plate, 6a : Air exhaust hole, 7: Insulating cylinder, : Self-destruction voltage characteristics, : Actual operating voltage vs. pressure characteristics.

Claims (1)

[Claims] 1 In a pressurized large current discharge switch in which the DC short-time breakdown voltage between the discharge electrodes/actual operating voltage is 2 or more, when applying the trigger voltage to the discharge electrode 1 on the capacitor side, the spark irradiation gap provided in the discharge electrode 1
The trigger voltage is shared by the inductance of the ferrite core Fe inserted in a circuit between the discharge electrode 1 and the main capacitor C ₁ while spark discharge is performed with G ₂ , and the capacitor is activated in a short period of time until the ferrite core Fe is saturated. A large current discharge switch characterized in that the charging voltage + the voltage shared by the ferrite core is equal to or higher than the DC short-time breakdown voltage of the discharge switch gap _G1 to break down the insulation of the discharge switch gap _G1 and cause discharge.