JP5332411B2 - Pulse power supply cooling system - Google Patents

Description

  The present invention relates to a pulse power source that generates a large current / high voltage pulse having a narrow width at a high repetition frequency, and more particularly to a cooling device that cools a main circuit element constituting the pulse power source by immersing it in an insulating oil tank.

A pulse power source used for a laser gas excitation power source of an excimer laser is configured in a main circuit shown in FIG. 4, for example. The pulse generation circuit is provided with a first-stage capacitor C0 for power, and this first-stage capacitor C0 is initially charged by a high-voltage charger HDC. When the semiconductor switch SW is turned on, a pulse transformer is passed from the first-stage capacitor C0 via a saturable reactor SI0. A pulse current I ₀ is generated in PT. Saturable reactor SI0 is, by generating the pulse current I ₀ and saturation operation after fully on the semiconductor switch SW, to reduce the duty of the semiconductor switch SW, to reduce the switching losses.

A magnetic pulse compression circuit is connected to the secondary side of the pulse transformer PT, and the pulse current I ₀ is boosted by the pulse transformer PT to become the pulse current I _{1. The} capacitor C 1 is charged with a high voltage, and the charge voltage of the capacitor C 1 is acceptable. by saturable reactor SI1 operate magnetic switch, high pressure charge the capacitor C2 is applied to the capacitor C2 magnetic pulse compressed narrow the pulse current I ₂ in the illustrated direction. Further, the saturable reactor SI2 operates as a magnetic switch with the charging voltage of the capacitor C2, so that a further narrow pulse current I ₃ flows in the direction shown in the figure, and the load LH such as the laser head chamber has a narrow and high voltage. The pulse current I ₃ is repeatedly supplied.

  Here, in the core used for the saturable reactors SI0 to SI2 and the pulse transformer PT, a hysteresis loss and an eddy current loss due to a high repetition pulse current flowing in the winding occur, and the temperature rises. Further, the semiconductor switch SW also generates heat due to loss during the switching operation. These heat generating main circuit elements are immersed in insulating oil for cooling (the semiconductor switch SW may be water-cooled or air-cooled outside the oil-tight tank). Capacitors C1 and C2 are arranged in a single unit in the tank because they are arranged close to each other so that a narrow pulse current can flow between saturable reactors SI0 and SI1. As the refrigerant stored in the tank, a highly insulating liquid such as insulating oil or fluorinate is used. In order to prevent these main circuit elements from being damaged by heat generation and performance deterioration, the main circuit elements (SI0, SI1, SI2, PT, C1, C2) are stored in an insulating oil tank indicated by a wavy line block in FIG. Cool down.

  FIG. 5 shows an example of the configuration of a conventional pulse power supply cooling device, in which a motor-driven crossflow fan is used as a stirrer, and insulating oil that also serves as a refrigerant for the cooling device is circulated (forced convection) between the main circuit element and the radiator. The main circuit element is cooled (for example, refer to Patent Documents 1 and 2). In FIG. 5, the tank 11 is formed of a nonmagnetic material such as stainless steel or aluminum, and the insulating oil 12 is housed inside the tank 11, and an air layer is formed between the oil surface and the lid 13 in the upper part of the tank 11. It is possible to absorb the volume expansion of the insulating oil. The main circuit element portion 14 of the pulse power supply is immersed in the insulating oil 12, and a radiator 15 is provided in parallel on the upper side portion thereof, and cooling water is passed through the radiator 15 from the outside of the tank 11. A cross flow fan 16 is provided below the radiator 15, and the cross flow fan 16 is driven by a motor 18 outside the tank 11 via a magnetic coupling 17, thereby insulating oil from the main circuit element unit 14 and the radiator 15. The main circuit element unit 14 is cooled. In this cooling method, since the flow of insulating oil is generated in the vertical direction by the rotation of the cross flow fan 16 with respect to the main circuit element unit 14, the inside of the tank 11 can be uniformly stirred, and heat exchange is promoted. Cooling efficiency can be increased.

FIG. 6 shows another configuration example of a cooling device for a pulse power supply, and the main circuit element is cooled by circulating insulating oil between the main circuit element and the radiator using a motor-driven axial fan as a stirrer (for example, Patent Document 1). reference). In FIG. 6, the main circuit element part 14 is immersed in the lower part of the insulating oil 12 in the tank 11, and the flat radiator 19 is provided in the upper part. A fan 20 is provided in the lower part of the tank 11, and the fan 20 is driven by a motor 18 via a magnetic coupling 17, whereby insulating oil is circulated from the main circuit element unit 14 toward the radiator 19, and the main circuit element The part 14 is cooled.
JP 2001-136758 A JP 2003-124550 A

  In the conventional cooling device, in order to increase the cooling efficiency, it is conceivable to increase the number of circulations of the insulating oil by increasing the rotation speed of the stirrer forcing the insulating oil to convect. However, when the rotation speed of the stirrer is increased, the oil surface undulates and bubbles are trapped in the insulating oil as shown in FIG. 7 (a) or (b). When the entrained bubbles are circulated to the high-pressure part of the main circuit element, as shown in FIG. 7 (c), partial discharge occurs due to the bubbles with low withstand voltage, and deterioration of the insulating oil and pulse transformer windings occur. Insulators such as parts are deteriorated, and eventually dielectric breakdown occurs.

  An object of the present invention is to provide a cooling device for a pulse power source that can increase the circulation rate of insulating oil by increasing the number of revolutions of a stirrer and prevent bubbles from being generated in the insulating oil.

  In order to solve the above-mentioned problems, the present invention is provided with a metal or insulating wave breaker plate (or wave breaker) on the oil surface of the insulating oil or in the vicinity of the oil surface to prevent the liquid surface of the insulating oil from wavy. It is made to hold down with a board, and has the following structures.

(1) A radiator in which an insulating layer is stored with an air layer in the tank, the main circuit element part of the pulse power supply is immersed in the insulating oil, and cooling water flows from the main circuit element part and the outside of the tank. In the pulse power supply cooling device that circulates the insulating oil with a stirrer between
A metal or insulating wave- breaking plate that floats on the insulating oil is positioned on the surface of the insulating oil, and a spacer is provided that is fixed only to one of the wave-proofing plate or the tank lid, and between the oil surface and the tank lid. It is characterized by a structure in which a gap is provided in a part.

(2) A radiator in which an insulating layer is provided with an air layer in the tank, the main circuit element portion of the pulse power supply is immersed in the insulating oil, and cooling water flows from the main circuit element portion and the outside of the tank. In the pulse power supply cooling device that circulates the insulating oil with a stirrer between
The structure is characterized in that a metal or insulating wave-breaking plate is floated on the oil surface of the insulating oil so as to be movable in the vertical direction of the tank, and a gap is provided in part between the oil surface and the tank lid.

  As described above, according to the present invention, a metal or insulating wave breaker (or wave breaker) is provided on or near the oil surface of the insulating oil, and the liquid level of the insulating oil is Since it is suppressed, it is possible to increase the circulation rate of the insulating oil by increasing the number of revolutions of the stirrer, and to prevent the generation of bubbles in the insulating oil.

<Embodiment 1>
FIG. 1 is a configuration diagram of a cooling apparatus for a pulse power source according to the present embodiment, in which (a) shows an apparatus configuration using a cross flow fan, and (b) shows an apparatus configuration using an axial fan.

  5 differs from FIG. 5 or FIG. 6 in that a metal or insulating wave-breaking plate (or wave-blocking object) 21 is positioned semi-fixed on or near the oil surface of the insulating oil.

  The wave preventing plate 21 is provided with spacers 22 at a plurality of locations between the wave preventing plate 21 and the lid 13. The spacer 22 is fixed only to the wave preventing plate 21 or is fixed only to the lid 13, and the height dimension for contacting the lid 13 in a state where the wave preventing plate 21 floats on the oil surface or is partially immersed in the oil surface. To. By interposing the spacer 22, the insulating plate is prevented from being lifted from the oil surface by forced convection of the stirrer, and the oil surface is not exposed to the air layer. And prevents bubbles from forming in the oil.

  The wave preventing plate 21 does not completely partition the oil surface and the lid 13 but provides a gap in part. As a result, the expansion due to the temperature rise of the insulating oil is released to the air layer.

  With such an apparatus configuration, even if the number of revolutions of the stirrer is increased, the oil surface does not wave and bubbles are not caught in the insulating oil, and the insulation breakdown voltage is low due to the bubbles flowing into the high-pressure part of the main circuit element. Partial discharge can be prevented from occurring due to bubbles. As a result, the rotation speed of the stirrer can be increased to increase the cooling efficiency, and further, the generation of bubbles in the insulating oil can be prevented to prevent the deterioration thereof, the deterioration of insulators such as the pulse transformer winding part, and the insulation breakdown.

<Embodiment 2>
2A and 2B are configuration diagrams of a cooling device for a pulse power source according to the present embodiment, where FIG. 2A shows a device configuration using a cross flow fan, and FIG. 2B shows a device configuration using an axial fan.

  5 or 6 differs from FIG. 5 or FIG. 6 in that a metal or insulating wave preventing plate (or wave preventing object) 23 is floated on the surface of the insulating oil so as to be movable in the vertical direction of the tank. .

  The support plate 24 has an L-shaped structure, one end is fixed to the side surface of the lid 13 or the tank 11, and both end surfaces of the wave preventing plate 23 are placed on and supported by the other L-shaped portion. . The height of the support plate 24 is set to a value at which the wave preventing plate 23 is in contact with at least the oil surface of the insulating oil at normal temperature.

  The wave preventing plate 21 does not completely partition the oil surface and the lid 13 but provides a gap in part. Thereby, the expansion due to the temperature rise of the insulating oil is released to the air layer.

  According to the present embodiment, the wave preventing plate 23 is movably supported by the support plate 24 in the height direction of the tank, and the wave preventing plate 23 can be floated on the oil surface at normal temperature. As a result, the wave breaker plate 23 can always float on the oil surface, and the wave breaker plate (or wave breaker) floats as the oil level rises compared to the first embodiment. A large flow path in the vicinity of the (heating element) and the radiator (endothermic body) is secured to increase the flow velocity, further improving the cooling efficiency.

<Embodiment 3>
FIG. 3 is a configuration diagram of a cooling device for a pulse power source according to the present embodiment, where (a) shows a cross-sectional view of the device configuration using a crossflow fan, (b) shows a side view, and (c) shows an oil surface. The form at the time of ascent is shown.

  5 is different from FIG. 5 in the height position where the metal or insulating wave blocking plate (or wave blocking object) 25 is in contact with the oil surface of the insulating oil, or the height position where a part of the oil surface is immersed. The point is that the fins 26 are integrated between the wave preventing plate 25 and the lid 13.

  The fin 26 has a structure in which a plurality of metal plates having excellent heat conductivity are arranged, and a groove direction formed by the metal plates is the same as the circulation direction of the insulating oil.

  The lid 13 is made of a metal having excellent thermal conductivity. Further, the wave preventing plate 25 does not completely partition the oil surface and the lid 13 but provides a gap in part. As a result, the expansion due to the temperature rise of the insulating oil is released to the groove of the air layer formed by the fins 26.

  According to the present embodiment, since the wave preventing plate 25 is made of metal and integrated with the fin 26 and the lid 13, the wave preventing plate or the wave preventing object also serves as a radiator, and the uppermost portion of the insulating oil at which the temperature is highest. It is possible to efficiently dissipate heat to the lid 13 side through the fins 26 from the wave blocking plate 25 in contact with the heat shield plate 25, and the cooling efficiency can be further improved. In particular, since a large amount of oil flows through the fins when the oil level rises, the heat dissipation effect is increased.

1 is a configuration diagram of a pulse power supply cooling device according to Embodiment 1. FIG. FIG. 5 is a configuration diagram of a cooling device for a pulse power source according to a second embodiment. FIG. 6 is a configuration diagram of a cooling device for a pulse power supply according to a third embodiment. The block diagram of the main circuit of a pulse power supply. The structural example of the cooling device of the conventional pulse power supply. The other example of a structure of the cooling device of the conventional pulse power supply. Explanatory drawing of bubble generation and partial discharge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Tank 12 Insulation oil 13 Cover 14 Circuit element part 15, 19 Radiator 16 Cross flow fan 17 Magnetic coupling 18 Motor 20 Axial fan 21, 23, 25 Wave barrier plate 22 Spacer 24 Support plate 26 Fin

Claims (2)

Insulating oil is stored in a tank with an air layer, and the main circuit element part of the pulse power supply is immersed in this insulating oil. Between the main circuit element part and the radiator through which cooling water flows from outside the tank In a pulse power supply cooling device that circulates insulating oil with a stirrer,
A metal or insulating wave- breaking plate that floats on the insulating oil is positioned on the surface of the insulating oil, and a spacer is provided that is fixed only to one of the wave-proofing plate or the tank lid, and between the oil surface and the tank lid. A cooling device for a pulsed power supply, characterized in that a gap is provided in a part of the pulse power supply. Insulating oil is stored in a tank with an air layer, and the main circuit element part of the pulse power supply is immersed in this insulating oil. Between the main circuit element part and the radiator through which cooling water flows from outside the tank In a pulse power supply cooling device that circulates insulating oil with a stirrer,
A pulse characterized by a structure in which a metal or insulating wave barrier is floated on the oil surface of the insulating oil so that it can move in the vertical direction of the tank, and a gap is provided in part between the oil surface and the tank lid Power supply cooling device.

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