JP2000295835A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure increase of a tolerable current being by using three protective elements by devising the arrangement, thereby lessening the unbalance of a current even if such circuit constitution as to connect three protective elements in parallel is adopted. SOLUTION: Three fuses 1A1, 1A2, and 1A3, which constitute a protector to be connected in series to a semiconductor element 2A, are arranged in triangular form or equilaterally triangular form. As a result, the inductance between each fuse and the semiconductor element 2A becomes approximately equal, thus making small the unbalance percentage of the allotted current of each fuse 1A1, 1A2, and 1A3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a power converter,
In particular, the present invention relates to an arrangement of a protection element in a protection device connected in series to each of a plurality of semiconductor elements constituting a power conversion device.

[0002]

2. Description of the Related Art A power conversion device such as a rectifier or an inverter is a diode, a thyristor, a GTO or an IGB.
A plurality of semiconductor elements such as T are used, and a circuit suitable for each application such as a bridge circuit is adopted. Should one of the semiconductor elements break down during the operation of the power converter, the circuit becomes conductive and short-circuits the power supply, leading to the destruction of the entire power converter. Because of the danger, a circuit configuration in which a fuse as a protection element is inserted in each semiconductor element in series is adopted. In such a circuit configuration, when the semiconductor element is short-circuited, the current flowing through the semiconductor element increases. Therefore, when the current reaches the current set in the fuse, the fuse cuts off the current. Thermal and electromagnetic destruction is avoided. Further, in order to protect the semiconductor element itself, a circuit configuration similar to the above, in which a fuse as a protection element is inserted in series with each semiconductor element, may be adopted.

FIG. 2 is a circuit diagram of a rectifier, which is one of the power converters, and has a single-phase bridge connection. As is well known, a single-phase bridge includes four arms 11, 12, 21, 22 as shown.

The arm 11 is configured by connecting one semiconductor element 2 and a protection device including two fuses 1 connected in parallel, in series.
Are connected by the connection conductor 3. Other arms 12, 2
The same applies to 1 and 22.

In this protection device, the protection element 2
The two fuses 1 are connected in parallel because the semiconductor element 2
This is because one fuse does not have enough allowable current for the current capacity of.

[0006] Improvements and developments of semiconductor devices have been continued, so that a larger current can be borne by one semiconductor device. On the other hand, since there is no fuse serving as a protection element having such a large current capacity, one fuse is insufficient in the allowable current with respect to the current capacity of the semiconductor element 2, and thus two fuses are used. 1 is connected in parallel.

FIG. 3 is a two side view of one arm.
(A) is an elevation view and (b) is a plan view. In this figure, a semiconductor element 2 is connected to two fuses 1 via a connection conductor 3 (corresponding to a connection line 3 in FIG. 2). The two fuses 1 are arranged on the same straight line as the semiconductor element 2 as shown. When the number of the fuses 1 arranged on the same straight line as the semiconductor element 2 is two in parallel, the two fuses 1 are arranged close to the anti-semiconductor 2 side of the connection conductor, so that the semiconductor element 2 Since the respective inductances between the two fuses 1 and the two fuses 1 can be made substantially equal, the current sharing of the two fuses 1 is substantially balanced so that half of the current of the semiconductor element 2 flows through each fuse 1. Can be

FIG. 4 is a circuit diagram of a power converter different from that of FIG. 2. The difference from FIG. 2 is that three fuses 1A are connected in parallel. Subscript A
To eliminate duplicate descriptions.

FIGS. 5A and 5B are two views of one arm of FIG. 4, wherein FIG. 5A is an elevation view and FIG. 5B is a plan view. In this figure, as in the case of FIG. 3, the three fuses 1A are arranged on the connection conductor 3A so as to be aligned with the semiconductor element 2A. In the case where the number of fuses 1A arranged on the same straight line as the semiconductor element 2A is three,
Three fuses 1 are provided on the anti-semiconductor element 2A side of the connection conductor 3A.
Even if A is arranged close to each other, the respective inductances between the semiconductor element 2A and the three fuses 1A cannot be made equal to each other when the number of parallel connections is two. 5, the allowable current of the fuse 1A in the case of FIG. 5 is set to 2 and the allowable current of the fuse 1A in the case of FIG. There is a phenomenon. Therefore, FIG.
The circuit configuration in which three fuses are connected in parallel as shown in FIG. 5 is not adopted. Instead, when the allowable current is not enough with the two fuses in the circuit configurations in FIGS. In practice, a circuit configuration in which two fuses are provided for each semiconductor element is employed.
In this case, the burden current of the semiconductor element is reduced by half compared to the case of one semiconductor element, and a semiconductor element having a small rated current corresponding to the current is used.

[0010]

As described above, even when the current of one arm is sufficient for one semiconductor element, if the allowable current of the fuse is not enough in the parallel connection of two fuses, one arm is required. A circuit configuration is adopted in which two semiconductor elements are used and two fuses are connected in parallel to each semiconductor element. However, the number of semiconductor elements 2 is doubled while saying that the rated current may be small. The problem is that the price of the entire semiconductor device becomes high. That is, the price of one semiconductor element and two semiconductor elements whose rated currents are half that of the former is lower. There is also a problem that the number of connection conductors increases as the number of semiconductor elements doubles, and the configuration of the entire device becomes complicated.

An object of the present invention is to solve such a problem and to improve the arrangement so as to minimize the current imbalance even when employing a circuit configuration in which three protection elements are connected in parallel. An object of the present invention is to provide a power converter capable of securing an increase in allowable current due to the use of a power converter.

[0012]

According to the present invention, a protective device is connected in series to each of a plurality of semiconductor elements constituting a power converter, and three protective devices are provided. In a power converter including protection elements connected in parallel, by arranging three protection elements at the vertices of a triangle, the inductance between each protection element and the semiconductor element becomes substantially the same, and each protection element becomes The unbalance ratio of the shared current of the elements becomes smaller and closer to equilibrium.

Further, in this configuration, by arranging the three protection elements at the vertices of the equilateral triangle, the inductance between each protection element and the semiconductor element becomes more uniform, and the current shared by each protection element is reduced. The unbalance rate is smaller.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIGS. 1A and 1B are two views of one arm of FIG. 4 showing an embodiment of the present invention. FIG. 1A is an elevation view, FIG. 1B is a plan view, and the difference from FIG. This is a point where two fuses 1A1, 1A2 and 1A3 are arranged at the vertices of a triangle as shown in the figure. That is, a Y-shaped connection conductor 3C is attached to the end of the connection conductor 3B opposite to the semiconductor element 2A, and fuses 1A1, 1A2, and 1A3 are connected to the respective ends of the three branch portions of the connection conductor 3C. It is attached.

Since the fuses 1A1, 1A2, and 1A3 are arranged in this manner, the inductance between each fuse and the semiconductor element 2A is smaller than when the fuses are arranged on a straight line as shown in FIG. As a result, the unbalance ratio of the current sharing is reduced, and as a result, the number of fuses can be increased from two to three to increase the allowable current. Therefore, even when the current of one arm is sufficient for one semiconductor element, or when the allowable current of the fuse is not enough in the parallel connection of two fuses, a circuit with only three fuses can be configured. .

In FIG. 1, the fuses 1A2 and 1A3 are arranged at positions oblique to the length of the connection conductor 3B.
Although the configuration is such that the fuse 1A1 is disposed at a right angle position, the configuration is not limited to this, and an arrangement in which the fuse 1A1 is rotated in parallel with the paper surface may be employed. In any case, fuse 1
Any configuration may be used as long as the respective inductances between A1, 1A2, 1A3 and the semiconductor element 2A have the same value as much as possible.

A P terminal (not shown) and a fuse 1A
In consideration of the inductance of the connecting portion between the fuses 1A1, 1A2 and 1A3, for example, the same Y-shaped connecting conductor as the connecting conductor 3C in FIG. 1 is also connected to the P terminal side of the fuses 1A1, 1A2 and 1A3. If the configuration is such that the central portion of the connection conductor is connected to the P terminal, the fuses 1A1, 1A2, 1A3
Of the fuses 1A1 and 1A
The utilization of 2,1A3 is further improved, and the allowable current can be further increased.

If the fuses 1A1, 1A2, 1A3 are arranged in an equilateral triangle as shown in the figure, the inductance between the fuses 1A1, 1A2, 1A3 and the semiconductor element 2A can be increased. It can be made equal, but this is not necessarily limited to an equilateral triangle, and it is only necessary that the lengths of the branch portions of the connection conductor 3C having three branch portions are equal.

In the above-described embodiment, the configuration using a fuse as a protection element has been described. However, the present invention is not limited to such a configuration. Generally, an overcurrent protection element is connected in series to a semiconductor element. Applicable to configurations.

[0020]

As described above, according to the present invention, by arranging three protection elements, such as fuses, at the apexes of a triangle, the inductance between each protection element and the semiconductor element becomes substantially the same. In addition, the unbalance rate of the shared current of each protection element is reduced. As a result, 1
One semiconductor element in one arm has a sufficient current capacity, but when the allowable current is not enough with two protection elements, the necessary allowable current can be secured by increasing the number of protection elements to three. In particular, there is no need to increase the number of expensive semiconductor elements, and the effect of reducing the cost of the device can be obtained.

Although a diode is shown as an example of a semiconductor element, the present invention is not limited to this, and other semiconductor elements such as thyristor, GTO, IGBT, etc. can obtain the same effects as described above. .

Further, by arranging the three protection elements at the vertices of the equilateral triangle, the inductance between each protection element and the semiconductor element becomes more uniform, and the unbalance ratio of the shared current of each protection element. Is smaller, so that the allowable current can be further increased.

[Brief description of the drawings]

FIG. 1 is a two-sided view of one arm of a power conversion device according to an embodiment of the present invention, in which a protection device including three protection elements connected in parallel is connected in series to one semiconductor element; (a) is a plan view and (b) is an elevation view.

FIG. 2 shows one semiconductor element of a conventional power converter.
Circuit diagram of a single-phase bridge connection in which a protection device including two protection elements connected in parallel is connected in series

3A and 3B are two views of one arm in FIG. 2, wherein FIG. 3A is an elevation view and FIG. 3B is a plan view.

FIG. 4 is a circuit diagram of a single-phase bridge connection in which a protection device including three protection elements connected in parallel is connected in series to one semiconductor element of a power conversion device different from FIG. 2;

5A and 5B are two views of one arm in FIG. 4, wherein FIG. 5A is an elevation view and FIG. 5B is a plan view.

[Explanation of symbols]

1, 1A, 1A1, 1A2, 1A3 ... fuse (protection element), 2, 2A ... semiconductor element, 3, 3A, 3B, 3C ...
Connection conductor

Claims (2)

[Claims] 1. A power converter in which a protection device is connected in series to each of a plurality of semiconductor elements constituting a power conversion device, and the protection device includes three protection devices connected in parallel. A power converter, wherein the elements are arranged at the vertices of a triangle. 2. The power converter according to claim 1, wherein the three protection elements are arranged at the vertices of an equilateral triangle.