JPS643344B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a power conversion unit, and particularly to a GTO
(Get-Turn-Off) Relates to a type in which a semiconductor stack containing devices is immersed in a boiling coolant.

[Background of the invention]

FIG. 1 shows part of a general power converter circuit using a GTO element. A snubber circuit 2 and a diode 3 are connected in parallel between the anode and cathode of the GTO element 1. The snubber circuit 2 includes a snubber diode 4 and a snubber capacitor 5 connected in series, and a resistor 6 connected in parallel to the snubber diode 4. Further, the gate and cathode of the GTO element 1 are connected to a gate drive circuit 7, and resistors 8, 9 and a capacitor 10 are connected between the gate and the cathode.

A power converter using such a GTO element generates heat, so the cooling method is an issue.The cooling method involves cooling the GTO element, diode, and the anode and cathode connectors of the GTO element together with a heat sink. A promising method is to stack them together and tighten them together using appropriate tightening means to form a so-called semiconductor stack, and then store this semiconductor stack in a tank and immerse it in a boiling refrigerant.

However, conventionally, a capacitor and a resistor (hereinafter referred to as GK
The tank was placed outside the tank, which caused the following problems. That is, in a power converter using GTO element 1 as described above, the GTO
Main circuit including element 1, snubber circuit 2 and gate
It is necessary to reduce the impedance between the gate and cathode of the GTO element 1 by minimizing the inductance of each wiring between the cathodes. The reason is that unless the voltage applied to the gate-cathode impedance is always lower than the grid-cathode barrier voltage inside the GTO element 1,
This is because the nature of the GTO element 1 causes false ignition. Therefore, in the conventional method of placing the GK-to-GK CR outside the tank, the wiring length between the gate and cathode becomes long, which increases the inductance and risks causing false ignition. In addition, in order to install the GK-to-GK CR outside the tank, a container that can withstand the external environment is also required.
This also has the disadvantage of increasing the size of the device as a whole.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a power conversion unit that eliminates the drawbacks of the prior art described above, does not cause erroneous ignition, and allows the entire device to be configured compactly.

[Summary of the invention]

In order to achieve the above object, the present invention provides a semiconductor stack in which a GTO element, a diode, an anode side connector, a cathode side connector, etc. of the GTO element constituting a power converter are stacked and fastened together with a heat sink, and the semiconductor stack is housed in a tank. And the GTO
GTO
The capacitor and resistor connected between the gate and cathode of the element are integrally molded with resin and connected between GK.
form a CR unit and connect this unit to the GTO
The device is characterized in that it is placed in the tank close to the device.

[Embodiments of the invention]

2 to 4 show an embodiment of the present invention, and parts corresponding to those in FIG. 1 are given the same reference numerals as in FIG. 1. Diode 3, connector 1
1. The cooling fin (heat sink) 12, the GTO element 1, the cooling fin 12, the connector 13, the insulator 14, and the spacers 15 and 16 are stacked and arranged in a sandwich pattern, and the center part of the spacer 16 has good heat and electrical conduction. Bracket 1 through ball 17
By pressing with 8, each of the above-mentioned parts is crimped. The outer circumferential end of the bracket 18 is fastened to the opposite bracket (not shown) by a stud bolt 19 and a nut 20, and when the nut 20 is tightened, the pressing force is exerted. The stud bolt 19 is covered with an insulating tube 21,
Further, a claw ring 22 for preventing loosening is interposed between the bracket 19 and the nut 20. Note that the reference numeral 23 (see FIG. 3) is a cathode side connector of the GTO element 1.

The above is the configuration of the semiconductor stack 24, and in this embodiment, the cathode side connector 23 is connected between GK and GK.
By supporting CR unit 25, GK
The inter-CR unit 25 is arranged close to the GTO element 1.

The GK inter-GK CR unit 25 has a structure as shown in FIGS. 5 and 6. That is, the capacitor 10 and the resistors 8 and 9 are placed on both sides of the insulating plate 26, and their respective terminals are connected to form a circuit between G and K in FIG. The capacitor 10 and resistors 8 and 9 attached to the insulating plate 26 are housed in a flat stainless steel case 2.
It is housed in 7. Terminals 30A and 30B supported by insulators 29A and 29B are passed through one end plate 28 of the case 27, and plugs 32A and 32B are inserted through the other end plate 31 to seal the two holes.
is inserted. The insulating plate 26 is fixed to the inner surface of the one end plate 28 with bolts 33. In addition, terminal 30A is connected to capacitor 10 and resistor 9.
The terminal 30B is connected to the connection point of both resistors 8 and 9 by insulated lead wires 34A and 34B, respectively. Further, each of these parts is integrally molded with a molding resin 35 such as epoxy resin filled in the case 27. This resin 35 is obtained by removing the aforementioned plugs 32A and 32B, injecting the liquid into the case 27, and hardening it. After injection or hardening, the plugs 32A and 32B are closed again. Resin 35 is case 2
It is preferable to fill all the spaces within 7, but if this is difficult, it is acceptable to leave some spaces 36 as shown in the figure. Note that a resilient resin layer 37 such as silicone resin is previously applied to the outer periphery of the capacitor 10 and the resistors 8 and 9.
It is preferable to coat the mold resin 35 with the capacitor 10, the resistors 8 and 9, and the mold resin 35. Although not shown, it is also possible to provide an elastic resin layer on the inner surface of the case 27.
Effective in absorbing differences in thermal expansion and buffering against external impact. Mounting plates 38 are provided on both sides of the case 27, and the GK inter-GK CR unit 25 uses the mounting plates 38 to attach the semiconductor stack 2 as described above.
It is fixed at 4.

As shown in FIGS. 3 and 4, the semiconductor stack 24 and the GK inter-GK CR unit 25 configured as described above are housed in a sealed tank 39 and immersed in a boiling refrigerant 40. be done. Furthermore, the semiconductor stack 24 is connected to a main bushing 41 and an auxiliary bushing 42 provided at the ends of the tank 39, as shown in FIG.

In the above power conversion unit,
Refrigerant 40 in tank 39 due to heat generated by GTO element 1, etc.
is boiled and the pressure inside the tank 39 increases, but the capacitor 10 and the resistors 8 and 9 are connected to the metal case 27.
Since it is housed inside and embedded in the resin 35, it will not be damaged by the above pressure.
In addition, the capacitor 10 and the resistors 8 and 9 are arranged on both sides of the insulating plate 26 and housed in the metal case 27, so that the overall structure is flat. It is easy to store in the tank 39 without taking up much space, and the whole can be made compact.
In addition, since the capacitor 10 and resistors 8 and 9 are placed near the GTO element 1, the wiring length between the gate and cathode can be shortened, reducing wiring inductance and preventing false firing. . Furthermore, the GK CR unit 25 has a structure in which the thermally weak capacitor 10 and the heat generating resistors 8 and 9 are arranged on both sides of the insulating plate 26, so that the capacitor 10 and the resistors 8 and 9 are thermally easily isolated. Therefore, the safety of the capacitor 10 can be improved. Also
Since the GK CR unit 25 is immersed in the boiling refrigerant 40, the heat generated therein is absorbed by the refrigerant 40, preventing excessive temperature rise, and improving reliability.

In the embodiment described above, the GK inter-GK CR unit is housed in a metal case, but if the molded resin is safe against boiling refrigerants, the metal case can be omitted.

FIG. 7 shows another example of the inter-GK CR unit used in the present invention. This GK inter-GK CR unit 25
In x, the capacitor 10 coated with an elastic resin layer 37 and the resistors 8 and 9 are housed in an insulating tube 43, and the void in the insulating tube 43 is filled with resin 35 for molding. This GK CR unit 2
5x is also placed beside the semiconductor stack as described above and housed in a tank filled with boiling refrigerant.

〔Effect of the invention〕

As explained above, according to the present invention, between goalkeepers
Since the CR is made into a unit by resin molding and housed inside the tank, there is an advantage that the entire power conversion unit becomes compact, and the GTO
Since the inductance of the wiring between the gate and cathode of the device is reduced, there is an advantage that erroneous firing of the GTO device can be prevented. Furthermore, since the GK inter-GK CR unit is immersed in the boiling refrigerant together with the semiconductor stack, there is no risk of overheating, which has the advantage of improved reliability.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a part of a general power converter using a GTO element, Figs. 2 to 6 show an embodiment of the present invention, and Fig. 2 shows an example of a semiconductor stack. 3 is a cross-sectional view of the right end surface of the semiconductor stack of a power conversion unit in which the same semiconductor stack is housed in a tank, FIG. 4 is a partially cut-away front view of the same power conversion unit, and FIG. 5 is a partially cut-away front view of the same power conversion unit. A sectional view of the GK-to-GK CR unit in the power conversion unit, FIG. 6 is a terminal side end view of the GK-to-GK CR unit, and FIG. 7 is a GK-to-GK CR unit used in the present invention.
FIG. 7 is a sectional view showing another example of the CR unit. 1...GTO element, 8, 9...resistance, 10...
Capacitor, 12... Cooling fin (heat sink), 24... Semiconductor stack, 25... Between GKs
CR unit, 26... Insulating plate, 27... Metal case, 35... Resin, 39... Tank, 40...
Boiling refrigerant.

Claims (1)

[Claims] 1. A semiconductor stack formed by stacking and tightening a GTO (gate turn off) element, a diode, an anode side connector, a cathode side connector, etc. of the GTO element together with a heat sink, which constitutes a power converter, is placed inside a tank. The capacitor and resistor connected between the gate and cathode of the GTO element are integrally molded with resin, and the GTO element, etc. is housed in a boiling refrigerant that absorbs heat generated and evaporates. A power conversion unit characterized in that a GK-to-GK CR unit is formed between the GTO element and the GTO element, and this unit is installed in the tank in close proximity to the GTO element. 2 In claim 1, between the goalkeepers
The CR unit is a power conversion unit that is housed in a metal case. 3 In claim 1, the above-mentioned G.K.
The CR unit is a power conversion unit characterized in that an insulating plate is interposed between the capacitor and the resistor. 4. The power conversion unit according to claim 1, wherein the capacitor and the resistor have an elastic resin layer around them. 5. The power conversion unit according to claim 2, wherein the metal case has an elastic resin layer on its inner surface.