JPH05315205A - Connection method of electrolytic capacitors - Google Patents

Abstract

PURPOSE:To provide a parallel connection of capacitors, whose inductance is reduced to keep circuit impedance from increasing. CONSTITUTION:When a plurality of electrolytic capacitors C are connected in parallel, their individual positive terminals are connected to one another and their individual negative terminals are connected to one another. A conductive plate which is connected to the negative terminal at the final connection stage is folded toward the input side, so that the direction of an electric current flowing in the conductive plate is opposite to the direction of an electric current flowing in the individual terminals. Thereby, magnetic fluxes which are generated when an electric current is applied are offset.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage source inverter, and more particularly to a method for connecting an electrolytic capacitor used in a DC circuit portion of a transistor inverter.

[0002]

2. Description of the Related Art In recent years, there has been a great demand for transistor inverters, and they have been widely used as voltage type inverters in, for example, variable speed devices.

FIG. 4 is a schematic circuit diagram of a transistor inverter, which is a DC circuit between a forward conversion section for converting commercial power into DC power and an inverse conversion section for converting DC power into AC power and leading to the induction motor IM. An electrolytic capacitor C is connected in parallel to the section.

In such a circuit configuration, as the capacity of the variable speed device increases, the capacity of the electrolytic capacitor C also needs to increase. Therefore, usually, a plurality of electrolytic capacitors C are connected in parallel to cope with a large capacity. Also,
It is often practiced to connect a plurality of electrolytic capacitors C in parallel in order to reduce the load sharing and obtain a uniform capacitor life.

[0005]

By the way, in the transistor inverter, it is advantageous in terms of cost to suppress the voltage rise due to the impedance of the circuit and use it within the limit of the transistor current capacity. For that purpose, it is important to reduce the inductance component of the circuit constituent conductor.

However, conventionally, there has been a problem that as the number of the electrolytic capacitors C connected in parallel increases, the conductive member connecting each terminal also becomes longer and the inductance component thereof increases.

The present invention has been made in view of the above problems, and an object thereof is to provide a connection method capable of reducing the inductance of a conductive member when a plurality of electrolytic capacitors are connected in parallel. .

[0008]

A method of connecting an electrolytic capacitor according to the present invention is a method of connecting a positive electrode terminal and a negative electrode terminal of a plurality of electrolytic capacitors in parallel, and a first method for connecting positive electrode terminals to each other. A conductive member, a second conductive member that connects the negative electrode terminals to each other, and a conductive member that is adjacent to each of the conductive members via an insulating member, and has one end of the first or second conductive member folded back to the other end. The third conductive member is provided, and the direction of current flowing through the third conductive member is opposite to the direction of current flowing through the first and second conductive members.

[0009]

When a current flows through the first and second conductive members, a clockwise magnetic flux is generated in a plane perpendicular to the current direction outside the conductor. Here, when the third conductive member is folded back from one end to the other end of any of these conductive members, the current directions are opposite to each other, so that the magnetic fluxes are canceled and the inductance component is reduced.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is an explanatory view of a method of connecting an electrolytic capacitor according to the present invention. As shown in FIG. 1, according to the present invention, when a plurality of electrolytic capacitors C are connected in parallel, each positive electrode (+) terminal and each negative electrode (−) terminal are electrically connected, and the negative electrode of the final connection stage is connected. The conductive member connected to the terminal is folded back to the starting end side.

FIG. 2 is an electrode connection state diagram of the electrolytic capacitor. The first conductive plate 1 electrically connects the positive electrode terminals of the electrolytic capacitor 10 to each other, the second conductive plate 2 electrically connects the negative electrode terminals to each other, and the folded back. The third conductive plate 3 used for is adjacent to the third conductive plate 3 via the insulating plate 4. By doing so, the direction of current flowing through the third conductive plate 3 is opposite to the direction of current flowing through the first and second conductive plates 1 and 2.

3A and 3B are external views of a capacitor unit that specifically realizes the present invention. FIG. 3A is a plan view and FIG. 3B is a front view. In this embodiment, an example of a unit formed by connecting five electrolytic capacitors 10 in parallel is shown. Referring to FIG. 3, the first to third conductive plates 1 to 3 are adjacent to each other in this order via the insulating plate 4, and each electrolytic capacitor 10
The positive electrode terminal is conductively connected to the first conductive plate 1 and the negative electrode terminal is conductively connected to the second conductive plate 2, and the terminal end of the second conductive plate 2 is conductively connected to the third conductive plate 3.

Then, the first conductive plate 1 and the third conductive plate 3 on the starting end side are formed into an L shape, and the positive and negative wiring terminals 1a and 3 are respectively formed.
a.

When connecting the capacitor unit having the above structure to the transistor inverter, the positive wiring terminal 1a is connected to the positive power source line and the negative wiring terminal 3a is connected to the negative power source line. Then, the current flowing through the first conductive plate 1 and the current flowing through the third conductive plate 3 have the same absolute value and the directions thereof are opposite to each other. Therefore, the magnetic flux generated around the conductive plates 1 to 3 by energization. Cancel each other out. As a result, the inductance component of each of the conductive plates 1 to 3 is significantly reduced and the circuit impedance is lowered, so that the inverter can be operated with a much lower current compared to the conventional electrolytic capacitor connection method.

In this embodiment, the case in which the terminal of the negative electrode terminal of the electrolytic capacitor is folded back has been described, but the structure in which the terminal of the positive electrode terminal is folded back may be adopted.

Further, in FIG. 3, five electrolytic capacitors 10 are provided.
Although an example of a capacitor unit formed by connecting in parallel is shown, the present invention is not restricted to this embodiment because the same effect can be obtained by connecting a larger number of electrolytic capacitors.

[0018]

As described above, according to the present invention, the positive electrode terminals and the negative electrode terminals of the electrolytic capacitor are first and second, respectively.
A second conductive member is used for conductive connection, and a third conductive member is provided, in which one end of these conductive members is folded back to the other end, and the third conductive member is connected to the first and second conductive members via an insulating member. Since it is arranged adjacent to the second conductive member, the magnetic flux generated by the energization of each conductive member is canceled, and the inductance component is significantly reduced. Moreover, this effect is
Even if the number of electrolytic capacitors connected in parallel is increased, the same result can be obtained, so that the connection method is suitable for large capacity applications.

Further, since the positive and negative wiring terminals to the electrolytic capacitor can be put together on the starting end side, the length of the conductive member can be reduced. Therefore, the voltage increase due to the increase in the impedance of the circuit is suppressed, and the use in the limit of the transistor current capacity is facilitated, so that the operating cost is significantly reduced compared to the conventional case.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method of connecting an electrolytic capacitor according to the present invention.

FIG. 2 is an electrode connection state diagram of an electrolytic capacitor for realizing the present invention.

FIG. 3 is an external view of a capacitor unit that realizes the present invention, in which (a) is a plan view and (b) is a front view.

FIG. 4 is a schematic configuration diagram of a transistor inverter as an application example of the present invention.

[Explanation of symbols]

 1 to 3 ... Conductive plate (conductive member) 4 ... Insulating plate (insulating member) 10, C ... Electrolytic capacitor

Claims (1)

[Claims] 1. A method for connecting positive electrode terminals and negative electrode terminals of a plurality of electrolytic capacitors in parallel, wherein a first conductive member connecting positive electrode terminals to each other and a second conductive material connecting negative electrode terminals to each other. A member and a third conductive member that is adjacent to these conductive members with an insulating member interposed therebetween, and has one end of the first or second conductive member folded back to the other end. A method of connecting an electrolytic capacitor, characterized in that the direction of the current flowing through is opposite to the direction of the current flowing through the first and second conductive members.