JPS61119068A - Snubber circuit of semiconductor switch - Google Patents

Abstract

PURPOSE:To enable the breaking capability of a semiconductor switch maximum reducing the stray inductance of the main circuit wiring in a snubber circuit with a simple stuck construction by using the external container of a condenser as an electrode. CONSTITUTION:The ends of terminal rods 1, 1 are connected to electrodes 2, 2 provided at both the ends of a condenser element 3 and one terminal rod 1 is insulated with an insulating material 15 from an external container (a conductor) 4 and is externally projected. The other terminal rod 1 is attached to the internal surface of the container and uses the container as an electrode. A terminal 16 is integrally installed on the external surface of the container. Since the terminal 16 provided on the external container of a condenser can be connected directly to the terminal 17 of a G.T.O. thyristor 5, wiring with a wire is unnecessary. The wiring from a rectifying diode 6 to a condenser 7 is also sufficient with a sort lead wire 18.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a snubber circuit for a semiconductor switch, in particular, a series connection body of a rectifier diode and a capacitor is connected in parallel with the semiconductor switch, and a resistor is connected in parallel with the rectifier diode. This is a book about snubber circuits that connect .

[Conventional technology]

Figure 4 is a front view across the outer box showing the structure of a conventional capacitor that is a component of a snubber circuit, where 1 is the positive and negative terminals, 2 is the electrode, 3 is the element of the capacitor body, and 4 is the outside. It represents a box.

FIG. 5 shows an example of a stack assembly using the above-mentioned conventional capacitor, and 5 is a gate turn-off thyristor (hereinafter referred to as G) as a semiconductor switch.

T, O thyristor), 6 is a rectifier diode, 7 is a rectifier diode,
8 is a capacitor, 8 is a cooling fin, 9 is a baking plate that insulates the capacitor 7 and the cooling fin 8, and 10 is other parts.

FIG. 6 shows an example of a snubber circuit. In Figure 6, 5
G, T, O thyristors control the power supplied from a power source (not shown) to a load (also not shown). A series connection body of the rectifier diode 6 and the capacitor 7 is connected between the anode and cathode of the G, T, O thyristor 5 in a direction in which current flows from the anode side to the cathode side. The resistor 11 is connected in parallel with the rectifier diode 6. Inductance 12 is composed of rectifier diode 6, capacitor 7, G, T, O
This is the stray inductance associated with the wiring connecting the thyristors 5.

In the snubber circuit diagram of FIG. 6, if we consider the case where the current i flowing through the G, T, 0 thyristor 5 is dialyzed by the gate turn-off operation of the G, T, 0 thyristor, then G, T
, O When the current of the thyristor 5 is cut off, the current i that has been flowing so far tries to bypass it through the rectifier diode 6 of the snubber circuit and the capacitor outer box. Current waveform 13 at this time. The voltage waveform 14 is shown in FIG.

Now, the dialysis rate t-di/ of G, T, O thyristor 5
dt, the rise of the current flowing through the rectifier diode 6 and capacitor 7 of the snubber circuit is also the same di/dt.
The speed will be . At this time, if the value of the stray inductance 12 included in the snubber circuit is tLs, then V
A step-like spike voltage of nsp −Ls −di /dt is generated. This spike voltage VDsp is G,
T, O is one of the important parameters of the gateter/off condition of thyristor 5, and this value is 600~1000v
When it reaches G, T. The dialysis capacity of the 0 thyristor 5 is significantly reduced.

In actual operation, it is desirable to suppress the spike voltage Vosp t to a value as low as possible, but the dialysis rate di/
Since the value of dt is determined by the driving conditions and unique characteristics of the G, T, and O thyristors themselves, it is very difficult to completely suppress fl. Therefore, the snow orgasm voltage VD6F
In order to lower the value of , it is necessary to reduce the value of stray inductance 12 included in the snubber circuit.

[Problem that the invention seeks to solve]

In the conventional snubber circuit as described above, in order to reduce the value of stray inductance included in the wiring connecting the rectifier diode, capacitor, and G, T, 0 thyristor,
It is important to make the wiring in the circuit configuration thicker and to keep the length of the wiring as short as possible.

For example, the value of stray inductance 12 Ls10.3μH
In order to achieve the following, the diameter of the wire must be 3.5 - or more, and a circuit including a rectifier diode and a capacitor must be constructed within 15 α between the terminals of the G, T, and O thyristors, and a snubber must be installed. There were extremely difficult problems in the assembly and configuration of parts such as circuits.

This invention is the ninth attempt to solve this problem, and reduces the stray inductance caused by the wiring of the snubber circuit, thereby reducing the stray inductance of the semiconductor switch (G).

The purpose of this invention is to provide a snubber circuit which improves the dialysis capacity of a T, 0 thyristor and whose circuit components are easy to assemble.

[Means for solving problems]

The snubber circuit according to the present invention uses the outer case of a condenser as a component as an electrode.

[Effect]

In this invention, by directly connecting the capacitor to the cooling fin, it is possible to reduce the value of stray inductance included in the snubber circuit by about 10 to 50 inches, solving the difficulty of circuit configuration due to extremely small wiring. At the same time, a snubber circuit configuration with lower inductance is possible, which promotes improvement of the dialysis characteristics when the G, T, and 0 thyristors are turned off.

〔Example〕

Fig. 1 shows the structure of a capacitor which is a component of the snubber circuit of the invention.
is exactly the same as the conventional capacitor mentioned above.

The ends of the terminal bars 1.1 are connected to the T electrodes 2.2 provided at both ends of the capacitor body element 3, and the terminal bars 1.
is insulated from the outer box (conductor) 4 via an insulator 15 and protrudes to the outside, and the other terminal rod 1 is attached to the inner surface of the outer box, using the outer box as an electrode. There is a terminal 1 on the outside of the outer box.
6 are integrally provided.

FIG. 2 shows an example of a stack configuration using the above capacitors, in which the terminal 16 provided on the outer box of the capacitor as an electrode is directly connected to the terminal 17 of the G, T, O thyristor 5.
Since it can be connected to, there is no need for wiring with electric wires. Friend, a short lead wire 18 is sufficient for wiring from the rectifier diode 6 to the capacitor 7.

The third factor is that the G, T, 0 thyristor 5 and the rectifier diode 6 are connected between the pair of cooling fins 8, 8 and their electrodes 19, 20.
The terminals 17 and 2.1 of the capacitor 7 are arranged so that they are in direct contact with each other, and the terminals 17 and 2.1 of the capacitor 7 are connected to the terminals 17 and 2.1 that protrude laterally from both terminals 5.6 and 2.1, respectively.
6 and the terminal 1t are directly connected, there is no wire wiring, the stray inductance can be more sufficiently reduced than in the case of FIG. 2, and the stack configuration is extremely simple.

In the above explanation, G is used as a semiconductor switch.

T. 0 thyristor, but other switching devices (e.g. transistors, thyristors)
Of course, it can also be applied to

〔Effect of the invention〕

As described above, according to the present invention, since the outer box of the capacitor is used as an electrode, this capacitor can be connected to the semiconductor switch and the rectifier diode at the closest distance, resulting in a simple stack configuration. At the same time, stray inductance in the main circuit wiring of the snubber circuit can be reduced, and the dialysis ability of the semiconductor switch can be maximized.

Furthermore, it is possible to easily solve difficult mechanical designs of components such as snubber circuits.

[Brief explanation of drawings]

Figure 1 is an alternating pressure side view across the outer box of a capacitor that is a component of the snubber circuit of the present invention, Figure 2 is a front view of the main parts showing a stack configuration using the capacitor, and Figure 3 is the stack. A front view showing another example of the configuration, FIG. 4 is a front view across the outer box of a conventional capacitor, FIG. 5 is a front view showing a stack configuration using the capacitor, FIG. 6 is a snubber circuit diagram, FIG. 7 is a diagram of current and voltage dialysis waveforms when the G, T, and O thyristors are turned off. 4...Outer box, 5...Semiconductor switch? (gate turn-off thyristor), 6... rectifier diode,
7... Capacitor, 11... Resistor, 16.
...Terminal. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. 11th! I 25ii1 Figure 3 4 @ 5m 9- Thread loose) F &(Naka'I,jlJ"'
10: Snubber n product

Claims (1)

[Claims] a semiconductor switch that controls the power supplied to the load;
A snubber circuit comprising a series connection body of a rectifier diode and a capacitor connected in parallel with the semiconductor switch, and a resistor connected in parallel with the rectifier diode, characterized in that the outer box of the capacitor is used as an electrode. Semiconductor switch snubber circuit.