JPH10327573A - Semiconductor stack of power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce current unbalance between semiconductor devices in the semiconductor stack of a power conversion device. SOLUTION: A wiring board 3 is constituted as a three-layered structure consisting of an alternating-current terminal layer U, a positive-pole terminal layer P, and a negative-pole terminal layer N. These layers are arranged in proximity to one another and in parallel with one another, in such a manner that the direction of currents flowing from the positive-pole terminal layer P to the alternating-current terminal layer U is opposite to the direction of the currents flowing from the alternating-current terminal layer U to the negative-pole terminal layer N. Thereby the field interferences of the semiconductor devices with each other is eliminated, and a current unbalance is reduced. Number 2 in the figure refers to a base on which the semiconductor devices 1 are to be mounted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor stack suitable for use in a power converter of an uninterruptible power supply (UPS).

[0002]

2. Description of the Related Art FIG. 6 shows an example of a circuit configuration of a conventional semiconductor stack, and FIG. 7 shows an example of the structure. That is, here, a total of eight semiconductor elements 1 are mounted on the base surface 2 of the cooling body, and one upper and lower arm is constituted by two upper and lower semiconductor elements, and four arms are connected in parallel. Structurally, as shown in FIG. 7, by fixing the large current wiring substrate 3 to the terminal of the semiconductor element 1, four-arm parallel connection is realized.

FIG. 8 is a side view of FIG. As is apparent from FIG. 8, the U layer (U phase) as an AC terminal is on the semiconductor element side, the positive terminal layer (P phase) is on the upper arm side, and the negative terminal layer (N phase) is on the lower arm side. Are arranged respectively.
Although not shown, a sheet for insulation is interposed between the respective layers. Reference numeral 4 indicates an electrolytic capacitor. The U-phase terminal is an input terminal when the power converter is a rectifier, and an output terminal when the power converter is an inverter. In any case, the U-phase terminal is an AC terminal.

[0004]

FIG. 9 (a) shows the direction of current flow when one of the upper arm elements is switched, and FIG. 9 (b) shows the current flow when one of the lower arm elements is switched. The flow direction is shown. From these figures, a magnetic field is generated at the broken line portion in the large current wiring board 3, and in the four-element type shown in FIGS. 7 and 8, the balance of the current flowing between the arms is caused by the mutual interference of the magnetic fields. As a result, there is a problem that current concentrates on one element.

FIG. 10 is a schematic diagram showing a conventional example of a heat pipe cooling body for cooling a semiconductor element. (A)
Is a plan view, and (b) is a side view. As shown in the figure, a base surface 2 on which the semiconductor element 1 is mounted, a heat pipe 5 inserted into the base surface 2 and radiating fins 6 are provided. In such a configuration, when the semiconductor element 1 generates heat and the heat is transmitted to the base surface 2, the heat pipe 5
The liquid inside evaporates and moves to the heat radiation fin 6 side. When the liquid is cooled on the heat dissipating fin 6 side, the liquid is solidified and moves to the base surface 2 side, so that heat is transferred.

An advantage of the configuration shown in FIG. 10 is that even if local heat concentration occurs on the base surface 2, heat is dispersed as a whole. Therefore, as described above, 1
The above-described heat pipe cooling body is employed to reduce the concentration of current and the concentration of heat in one element. However, in such a heat pipe cooling body, there is a problem in that the heat sink fins are not compact because the base surface and the radiating fins are connected via the heat pipe. Therefore, an object of the present invention is to prevent imbalance in the current flowing between the arms,
It is an object of the present invention to disperse local heat concentration and to make a semiconductor element cooling body compact.

[0007]

In order to solve such a problem, according to the present invention, a plurality of semiconductor elements and a positive terminal layer, a negative terminal layer, and an AC terminal layer for connecting them in parallel are provided. A positive terminal layer, a negative terminal layer, and an AC terminal layer of the wiring substrate are stacked in parallel with and close to each other in a semiconductor stack of a power conversion device including a wiring substrate formed of a wiring board and a cooling body for cooling the semiconductor element. The directions of the currents flowing between the AC terminal layer, the positive terminal layer, and the negative terminal layer are opposite to each other. According to the first aspect of the present invention, the AC terminal layer can be divided into two parts, and the two can be core-coupled (the third aspect of the invention).

According to a second aspect of the present invention, a plurality of semiconductor elements, a wiring board including a positive terminal plate, a negative terminal plate, and an AC terminal plate for connecting them in parallel, and a cooling body for cooling the semiconductor elements In the semiconductor stack of the power conversion device, the heat sink is inserted along a direction in which the semiconductor elements are connected in parallel with each other on the base surface on which the semiconductor elements are mounted, and Radiation fins are arranged on the back side.

[0009]

FIG. 1 is an external view showing a first embodiment of the present invention. Here, 16 semiconductor elements 1 are attached to the base surface 2 of the cooling body, and eight 1-arms composed of two upper and lower semiconductor elements are connected in parallel. FIG. 2 shows a side view of FIG. As is clear from FIG. 2, here, the U-phase is on the lower side, the N-phase is on the inner side, and the P-phase is on the upper side. is there. Further, a sheet for insulation is interposed between the respective layers.

FIG. 3 (a) shows the direction of current flow when one of the lower arm elements in FIG. 1 switches, and FIG. 3 (b) shows the direction of current flow when one of the upper arm elements switches. Is shown. As is clear from FIG. 3, since each layer is arranged in parallel and close to each other, when one of the lower arm element or the upper arm element switches, the current flowing through the wiring board 3 is (a) or ( Since the directions are opposite to each other as in b), the magnetic field generated by the current is canceled. As a result, even when a plurality of semiconductor elements 1 are connected in parallel, mutual interference due to the magnetic field between the arms is eliminated, so that the current balance flowing between the arms is improved, and current concentration on one semiconductor element is suppressed. You.

FIG. 4 is an external view showing a second embodiment of the present invention. This shows a cooling device for a semiconductor element, in which a heat pipe 5 is inserted along a base surface 2 on which a semiconductor element 1 is mounted and a direction in which the semiconductor element 1 is connected in parallel to the base surface 2. It is configured. Further, on the back side of the base surface 2, fins 6 for heat radiation are provided. As described above, since the heat pipes 5 are inserted along the direction in which the semiconductor elements 1 are connected in parallel, even if local heat is generated in some of the semiconductor elements, the heat is dispersed in the direction in which the semiconductor elements are arranged. This has the effect of reducing the current imbalance of the semiconductor element.

In particular, when the semiconductor element is an insulated gate bipolar transistor (IGBT) element, the current concentrates on a part of the element, and when heated, the electric resistance decreases, and the current further concentrates. Heat dispersion as described above is effective. Further, unlike the conventional example shown in FIG. 10, since the heat radiation fins are arranged immediately behind the base surface, there is also an advantage that the heat generation part and the heat radiation part are almost integrated and the size can be reduced.

FIG. 5 is an external view showing a third embodiment of the present invention. The basic configuration is the same as in FIG.
The layer portion is divided into two parts as shown in the figure, the substrates up to the respective terminals are arranged so that the current directions are opposite, and these are magnetically coupled by the core 7. Also in this example, as in the case of FIG. 1, the interference of the magnetic field between the arms is small, so that the factors that cause the current imbalance are the difference in the impedance inside the semiconductor element and each terminal (U terminal, P terminal, N terminal). This is the difference in impedance due to the difference in wiring distance between the terminal and the semiconductor element. However, since the current flowing in each of the two divided phases by the magnetic coupling by the core 7 becomes equal, FIG.
Since the wiring distance is reduced to about １ ／ as compared with that shown in FIG. 1, the current imbalance is further reduced. As a result, the heating of a part of the semiconductor element is also reduced, so that there is an advantage that the cooling body can be reduced.

[0014]

According to the present invention, the positive terminal layer, the negative terminal layer, and the AC terminal layer of the wiring board are laminated in parallel and close to each other, and the current flowing between the AC terminal layer, the positive terminal layer, and the negative terminal layer. By setting the directions to be opposite to each other, the current imbalance of each semiconductor element is reduced. In addition, in the above configuration, the AC terminal layer is divided into two parts, and the two are core-coupled to further reduce the current imbalance.
The advantage is that heat concentration can be avoided.
By disposing a heat pipe along the direction in which the semiconductor elements are connected in parallel on the base surface on which the semiconductor elements are mounted, and disposing radiating fins behind the base surface, local heat concentration is dispersed. This makes it possible to achieve compactness and the like.

[Brief description of the drawings]

FIG. 1 is an external view showing a first embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is an explanatory diagram of a current path in the present invention.

FIG. 4 is an external view showing a second embodiment of the present invention.

FIG. 5 is an external view showing a third embodiment of the present invention.

FIG. 6 is a circuit diagram showing a conventional example of a semiconductor stack.

FIG. 7 is a configuration diagram showing a conventional example of a semiconductor stack.

FIG. 8 is a side view of FIG. 7;

9 is an explanatory diagram of a current path in the case of FIG. 7;

FIG. 10 is a schematic diagram showing a conventional example of a cooling body.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor element, 2 ... Base surface, 3 ... Wiring board, 4 ... Electrolytic capacitor, 5 ... Heat pipe, 6 ... Radiation fin, 7
…core.

Claims (3)

[Claims] 1. A power conversion system comprising: a plurality of semiconductor elements; a wiring board including a positive terminal layer, a negative terminal layer, and an AC terminal layer for connecting the semiconductor elements in parallel; and a cooling body for cooling the semiconductor elements. In the semiconductor stack of the device, the positive terminal layer, the negative terminal layer, and the AC terminal layer of the wiring board are laminated in parallel and close to each other, and the current directions flowing between the AC terminal layer, the positive terminal layer, and the negative terminal layer are mutually different. A semiconductor stack for a power converter, wherein the semiconductor stack is configured to be reversed. 2. A power converter comprising: a plurality of semiconductor elements; a wiring board including a positive terminal plate, a negative terminal plate, and an AC terminal plate for connecting the semiconductor elements in parallel; and a cooling body for cooling the semiconductor elements. In the semiconductor stack of the device, a heat pipe is inserted into the cooling body along a direction in which the semiconductor elements are connected in parallel on a base surface on which the semiconductor elements are mounted, and a radiating fin is provided on the back side of the base surface. A semiconductor stack of a power conversion device, comprising: 3. The semiconductor stack for a power conversion device according to claim 1, wherein said AC terminal layer is divided into two parts and both are core-coupled.