JPH04177775A - Solid-state switch - Google Patents

Abstract

PURPOSE:To prevent overvoltage breakdown from occurring by thermal unbalance between solid-state switching elements, by stacking switch module groups, in a multi-stage structure of a sandwich type by using metal plates of heat pipes, and installing heat dissipating plates for cooling on the other ends of the heat pipes. CONSTITUTION:Solid-state switching elements 1, or switch modules 21, 22 are stacked in a multi-stage structure of a sandwich type by using metal plates 20A, 20B of heat pipes 20, and heat dissipating plates for cooling are installed on the other ends of the heat pipes 20. When one ends are heated by the heat generated by the solid-state switching elements 1, the other ends are cooled by a cooling fan 23, and therefore temperature difference is generated. But, at a heating part, liquid in a wick is vaporized, and vapor is generated. Said vapor passes through internal vapor channels on account of slight pressure difference, and travels and reaches a cooling part where the heat dissipating plates 2 are installed. The vapor is condensed in the cooling part, and plenty of latent heat is discharged. Thereby thermal balance between the solid-state switching elements can be maintained, and the overvoltage breakdown of the switching elements can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a solid-state switch applied to discharge-excited laser devices and the like.

[Prior Art] FIG. 2 is a block diagram of a conventional discharge excitation laser device disclosed in, for example, Japanese Patent Application No. 1163228.
A, IB are solid state switching elements with a switching time of 500 ns or less, 2A.

2B is a heat sink for cooling the solid state switching elements IA and IB, 3A, 3B, 6.7A and 7B are conductive plates for carrying large currents, 4 is a charging capacitor, 5 is a laser housing, 8
is a peaking capacitor, and 9 is a discharge electrode. Also,
FIG. 4 shows the structure of the discharge section in the form of an electrical circuit diagram. In the figure, 10 is a high voltage power supply, 1.1.12
is a charging reactor.

Next, the operation will be explained. In FIG. 4, from the high voltage power supply 10 to the charging reactor 11 - the charging capacitor 4
- Charge is accumulated in the charging capacitor 4 through the route of the charging reactor 12.

Next, when the solid state switching element IA is closed, the electric charge of the charging capacitor 4 is transferred to the peaking capacitor 8 through a transfer loop of the charging capacitor 4, the solid state switching element IA, the peaking capacitor 8, and the charging capacitor 4. Along with this, the voltage between the discharge electrodes 9 increases rapidly, and eventually the discharge space breaks down and the energy of the peaking capacitor 8 is input into the discharge field.

As a result, gas in the discharge space is excited, and laser light is extracted by stimulated emission. Here, the solid state switching elements IA and IB are stacked in multiple stages to increase the withstand voltage, and in order to increase the current capacity, a large number of solid state switching elements IA and IB are installed in parallel along the optical axis direction. When looking at the cross section, the switching element group is installed on the image side with respect to the temporary line drawn to bisect the discharge electrode. At this time,
The discharging energy transfer loop includes charging conduit laser 4 - conductive plate 6 - conductive plate 7A - solid state switching element IA.
- Conductive plate 3A - Conductive plate 6 - Counterclockwise loop of charging capacitor 4 and charging capacitor 4 - Conductive plate 6 - Conductive plate 7B - Solid state switching element IB - Conductive plate 3B - Conductive plate 6 - Charging capacitor 4 clockwise loops are formed. Since the current flows in the two loops in opposite directions,
They work to cancel each other's inductances (.

Furthermore, since the solid-state switching elements A and 1B are installed in a dispersed manner in the optical axis direction, the current does not once converge as in the case of using a Zyratron for the switch. As a result of the stiffening, the inductance of the transition loop can be made very small, resulting in high d v/d
By obtaining t, the discharge can be stabilized and made uniform. For example, a solid state switching element IA with a switching time of 40 ns.

When using IB, the total inductance is 100n
It becomes H or less.

[Problems to be Solved by the Invention] Since the conventional solid-state switch is configured as described above, the portion near the heat sink is cooled, but the cooling efficiency is poor depending on the interior and location. As a result, solid state switching elements (
FET, IGBT, SIT, or a switch with a similar switching time (on operation))
Alternatively, temperature unevenness may occur in each module incorporating a plurality of such elements, and due to variations in switching characteristics, overvoltage may be applied to elements that are not turned on, eventually causing destruction of the number J element. This invention was made to solve the above-mentioned problems, and aims to avoid heat imbalance between a plurality of solid-state switching elements and to obtain a highly reliable solid-state switch with improved cooling efficiency. .

[Means to solve the problem]

The solid-state switch according to the present invention includes a switch module group in which a plurality of solid-state switching elements or switch modules incorporating a plurality of solid-state switching elements are connected in series and parallel, and the solid-state switching elements or switch modules are arranged on a metal plate. When the metal plates are stacked side by side in a sandwich structure and the metal plates are used as a heat absorbing part with low thermal resistance, a heat pipe is provided with a heat sink for cooling at the other end.

[Effect]

The switch in this invention includes a solid state switching element,
Alternatively, the switch module is constructed by stacking the metal plates of the heat pipe in multiple layers in a sandwich-like manner and providing a cooling heat sink at the other end of the heat pipe, so that the switch delay occurs due to thermal imbalance between the solid-state switching elements. This prevents the risk of overvoltage damage to the switch.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the same parts as in FIGS. 2 to 4 are designated by the same reference numerals. In FIG.
Metal plate 20A at the other end.

20B is a multi-layered heat pipe in which solid state switching elements 1 are closely attached in a sand-like shape; 21 is a solid state switching element 1 or a plurality of solid state switching elements 1;
For example, when a switch module incorporating a FET module is constructed, a train is connected to the metal plate 20B with low thermal resistance, and 22 is a source that is closely connected to the metal plate 2OA at the same time.
1°22 is collectively called Sui Nchimojikuru Kimitsu 30.

23 is a cooling fan, and 24 is a current flowing through the switch module group 30.

Next, the operation will be explained. In general, the heat pipe 20 has a simple structure, has no operating parts, and is characterized in that it can emit a relatively large amount of latent heat with a small temperature difference. The structure and functions are as follows. heat pipe 20
The inner wall surface of the container is lined with a porous material (for example, a screen) called a wick, and after the container is evacuated, an appropriate amount of liquid (called a working fluid) is sealed. The working fluid in the vacuum-kept container evaporates, and the space inside the heat pipe is filled with steam equal to the saturated vapor pressure at the current temperature. At this time, if one end is heated by the heat generated by the solid state switching element 1, a temperature difference occurs because the other end is cooled by the cooling fan 23. In the heating section, the liquid in the wick evaporates, and the generated steam moves through the internal steam passage due to a slight pressure difference and reaches the cooling section provided with the heat sink 2. The transferred steam is condensed here and releases a large amount of latent heat.

This operation maintains a thermal balance between the solid-state switching elements, and for the switch module group 30, which requires switching timings to be aligned within +1 second, there is no imbalance in on-time and the worry of overvoltage application is eliminated.

〔Effect of the invention〕

As described above, according to the present invention, a switch module in which a solid state switching element or a switch module incorporating a plurality of solid state switching elements is connected in series and parallel is connected to a metal pipe of a heat pipe.

The heat pipe is stacked in multiple layers in a sandwich-like manner, and a cooling heat sink is installed at the other end of the heat pipe to prevent switching delays due to thermal imbalance between the solid-state switching elements, which may lead to overvoltage breakdown. In addition to preventing this, the solid-state switch has a high density and low inductance, which has the effect of enabling even faster response.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a solid state switch according to an embodiment of the present invention, FIGS. 2 and 3 are block diagrams of a conventional solid state switch,
FIG. 4 is a circuit diagram of a conventional discharge excitation laser device. In the figure, 1 is a solid state switching element, 2 is a heat sink,
20 is a pipe, 2OA, 20B is a metal plate, and 30 is a switch module group. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A switch module group in which a plurality of solid state switching elements or switch modules incorporating a plurality of solid state switching elements are connected in series and parallel, and the solid state switching elements or switch modules are arranged on a metal plate and stacked in multiple stages in a sandwich structure. A solid-state switch that has a metal plate as a heat absorbing part with low thermal resistance, and a heat pipe with a heat sink for cooling at the other end.