JPS6281983A - Main circuit of current source inverter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a current source inverter and relates to a structure of an arm element suitable for a current source inverter using transistors as self-extinguishing elements in each arm.

[Background of the invention]

The main circuit of a conventional current source inverter is an rAC servo motor and a microcomputer system. A DC reactor kDcL is inserted as a constant current source, and the inverter main circuit control Kl element is:
Transistors 81 to S6 and reverse blocking diodes D1 to
D6 is connected in series with the transistor in each arm as shown in the figure, and the main circuit control gl element on the converter side is constructed by connecting a reverse blocking type thyristor 8D1-8L)a as shown in Figure 5. Ta. As shown in FIG. 6, the main circuit control elements on the converter side include transistors S, ~Sat, and reverse blocking diodes D, ~D8, . was connected in series with a transistor as shown in the figure, and the current flowing into the three-phase fat conductor was controlled. Furthermore, conventionally, these main circuit elements are each mounted as individual independent elements in one control vehicle.
During that time, the necessary circuits were constructed by connecting them with thick wires that matched the current capacity.

This conventional example had two primary problems.

The first is that a power diode is normally used as a reverse blocking diode, so as shown in FIG. When switching to S-F,
, and until D8 is completely off, the circulating current rr shown by the dotted line flows and the on-state current of 87 is added to the normal circuit current IL of 2 as shown in Figure 810, so that the transistor s,.

Is the internal loss and heat generation of diode D large? Transistor S? , it is necessary to provide a margin for the capacitance of diode D.

The second problem is that the number of wiring lines connecting diodes and transistors increases, which increases the number of assembly and wiring steps.

[Purpose of the invention]

An object of the present invention is to provide a main circuit control element suitable for use in a current source inverter.

[Summary of the invention]

The present invention was developed in the case of a transistor module (a main circuit element with a structure in which a transistor chip is housed in a glass case and the current is increased from the terminals on the case), which has recently become popular. A high-speed diode (reverse recovery time trr≦lμs) chip is housed inside, and this is internally connected in series with a transistor to reduce the number of wires in the control cubicle and reduce power loss due to freewheeling current during switching. It was designed to do so.

[Embodiments of the invention]

FIG. M7 is a schematic diagram of a conventional transistor module element, in which transistors as shown in FIG. 8 are housed. (The module element may be a diode or a thyristor instead of a transistor. In short, it is sufficient that the semiconductor element is housed in a molded case as shown in Fig. 7.) 1 is a transistor chip, and 2 is a transistor chip. A metal plate for dissipating heat generated by the transistor chip 1; 3 an insulating material for electrically insulating the chip l and the metal plate 2; 4 a metal plate that is fitted in a molded case that houses the chip l; 2 and is completely tightly connected with adhesive or the like.

5 is a molded case 40 cover, which has external connection terminals E (emitter) and B (base).

C (collector) is attached, and the screw of this terminal is used to electrically connect to external wiring.

The emitter, base, and collector terminals of the transistor chip L are connected to the lead wires 6, 7.8, and the terminal E, respectively.
It is electrically connected to H and C.

The present invention includes a transistor chip 1 and a fast diode chip 9 with a reverse recovery time trr≦1 μs in the case of this module, as shown in FIG.
and connect the connecting leads 10 between those chips.
The module is connected in a wL'A manner and has a circuit configuration as shown in FIG. 3 or 84. By doing this, the circuit of the current source inverter becomes as shown in Figure 1, and the part surrounded by the one-dot chain line has a modular structure.

Wiring man-hours and mounting space can be significantly reduced. In addition, since a high-speed counterfeit reverse blocking diode is inserted in series with each switching transistor, the circulating current during switching is suppressed to a small level that can be ignored as shown in Figure 11, and the heat generated by the transistor is also reduced. This has the effect of allowing the use of transistors with one rank lower capacitance.

Further, as shown in FIG. 3 or FIG. 4, the module of the present invention has a connection point between an internal transistor chip and a diode chip that is brought out to the outside as a terminal A. Figure 12 or 13
As shown in the figure, a voltage dividing element such as a capacitor C1 or a resistor is connected externally, and the voltage applied to the transistor chip and high-speed diode chip in the module is controlled according to the withstand voltage of each chip. You can.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a main circuit element suitable for use in a current source inverter, which has low switching loss and is easy to mount.

[Brief explanation of drawings]

FIG. 1 is a main circuit configuration diagram of a current source inverter according to an embodiment of the present invention, FIGS. 2 and 3 are structural diagrams of a module element of the present invention, and FIG. 4 is a configuration diagram of another module element of the present invention. figure,
Figure 5 is a main circuit configuration diagram of a conventional current source inverter;
Figure 7 shows the main circuit configuration diagram of another conventional current source inverter.
The figure is a structural diagram of the module element, Figure 8 is a circuit diagram of the module element, Figure 9 is an explanatory diagram at the time of switching, and Figure 1
0 is a supplementary explanatory diagram of FIG. 9, FIG. 11 is a current waveform diagram at the time of switching according to the effect of the present invention, FIG. FIG. 3 is a diagram showing an example of how modules are connected. 9...High-speed diode chip.

Claims (1)

[Claims] 1. A main circuit of a current source inverter comprising a converter and an inverter in which transistors are bridge-connected, characterized in that a high speed diode is connected in series with each of the transistors. 2. The main circuit of a current source inverter according to claim 1, wherein the series circuits of the transistor and the high-speed diode are housed in the same module. 3. The current source inverter according to claim 2, characterized in that a lead is extended from a connection point of the series circuit of the transistor and the high-speed diode, and is configured to be connected to an external circuit as one terminal of the module case. main circuit.