JPH0223012B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a pulse transformer that ensures insulation between a gate pulse generation circuit and the gate of a gate turn-off type thyristor and transmits gate pulses.

[Background of the invention]

Generally, the off-gate current of a gate turn-off thyristor (hereinafter simply referred to as GTO) is required to be approximately one order of magnitude larger than the on-gate current. Additionally, in line with the demand for larger GTO current capacity, there is a demand for larger gate circuit current capacity. Furthermore, with the increase in the voltage of GTO elements, by connecting GTOs in series,
There is a demand for higher voltage GTO switch circuits.

For these reasons, it is necessary to increase the current capacity and dielectric strength of the insulated pulse transformer installed between the gate pulse generation circuit that generates the gate pulse that controls the on/off of the GTO and the gate of the GTO. Pressure resistance is required.

However, if the insulated pulse transformer is simply made to have a larger capacity and a higher withstand voltage, the winding size becomes thicker and at the same time the insulation dimension between the primary and secondary transformers increases. This increases the inductance and
There is a risk that the steepness of the pulse current will decrease and the arc-extinguishing characteristics of the GTO will deteriorate. Also,
The external shape of the insulated pulse transformer has become larger,
In the case of a GTO device formed from multiple GTOs, the entire device becomes large in size, the gate circuit wiring becomes long, the wiring inductance increases, and the steepness of the pulse current further decreases. There is a possibility that.

On the other hand, in order to generally increase the current capacity or voltage of the entire GTO device, a plurality of GTOs are often connected in parallel or in series. In such a case, the gate pulses applied to the gates of each GTO must be synchronized. but,
If the inductances of the gate circuits of each GTO do not match, the waveform of each gate pulse will be distorted.
GTO on or off cannot be synchronized and some
There is a risk that an excessive current will flow or an excessive voltage will be applied to the GTO, which may damage the GTO.

[Purpose of the invention]

An object of the present invention is to provide a large-capacity, high-voltage pulse transformer with reduced inductance. Another object is to provide a compact pulse transformer that has a structure that allows easy synchronization of on/off control of the GTOs in a GTO device in which a plurality of GTOs are connected in parallel or in series. It's about doing.

[Summary of the invention]

In the present invention, the number of turns of the off-gate primary winding to which the off-gate pulse is applied and the secondary winding connected to the gate of the GTO are made equal, and the strands of these windings are arranged in the same layer and in one turn. By winding the secondary windings next to each other and dividing the secondary winding into multiple parts according to the required current capacity and connecting them in parallel, the inductance is reduced, and the capacity and withstand voltage are increased. It is something.

Furthermore, the present invention provides a plurality of GTO
The aim is to easily synchronize the on/off control of each GTO connected in parallel or in series, and to make it more compact.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on examples.

FIG. 1 schematically shows a pulse transformer according to an embodiment of the present invention, and also shows main parts of a GTO device and a gate circuit to which the pulse transformer is applied.

As shown in Figure 1, the GTO device 1 has two
It is formed by connecting GTOs 1A and 1B in series. The pulse transformer 2 has a primary winding consisting of an off-gate primary winding 4, an on-gate primary winding 5, and a check primary winding 6, and two sets of secondary windings 7.
A and 7B are wound around one magnetic core 3. An off-gate pulse is applied to terminals P ₁ and P ₂ of winding 4, an on-gate pulse is applied to terminals P ₃ and P ₄ of winding 5, and a check pulse is applied to terminals P ₅ and P ₆ of winding 6. The signals are inputted from gate pulse generation circuits (not shown) in accordance with the polarities shown. Terminal S ₁ of secondary winding 7A is connected to GTO 1 via thyristors Th _1A and Th _2A connected in parallel with opposite polarity.
_The terminal _S2 is connected to the cathode _KA of GTO1A. Also, GTO1A
A resistor R _1A and a series circuit of a resistor R _2A and a capacitor C _A are connected between the gate G _A and the cathode K _A of . Similarly, terminals S ₃ and S ₄ of secondary winding 7B
Between the gate G _B and cathode K _B of GTO1B,
Thyristors Th _1B , Th _2B , resistors R _1B , R _2B , and capacitor C _B are connected.

In this configuration, the thyristors Th _1A and Th _1B control the on-gate current (overdrive current), and the thyristors Th _2A and Th _2B control the off-gate current. Also, the resistance R _1A ,
The circuit consisting of R _1B , resistors R _2A and R _2B , and capacitors C _A and C _B functions to ensure the dv/dt tolerance of GTOs 1A and 1B and to prevent erroneous firing. Now, when the on-gate pulse or the off-gate pulse is applied to the winding 5 or 4, the secondary windings 7A, 7B
A pulsed on-gate current or off-gate current is passed between the gate cathode of each GTO 1A, 1B, and the GTO 1A, 1B is turned on or off. The on-gate current and off-gate current are required to have waveform characteristics that are large and have a steep rise, that is, have a high steepness.In particular, the off-gate current must be a large current and have a high steepness. As mentioned above, this is not the case.

Therefore, the pulse transformer 2 of this embodiment has a second
By adopting the winding configuration and structure shown in FIG. 3 and FIG. 3, leakage inductance of electromagnetic coupling between primary and secondary is reduced, and the required steepness of the pulse current is ensured. That is, as shown in FIG. 2, the off-gate primary winding 4 is divided into two windings 4A and 4B, corresponding to the secondary windings 7A and 7B, and the corresponding primary and secondary windings are formed into two parts. line 4
The number of turns of A-7A and 4B-7B is made equal.
The turns ratio can be adjusted by equalizing the number of turns between the primary and secondary windings by dividing the secondary windings 4A and 4B into a plurality of parts according to the off-gate current capacity, and connecting them in parallel. ing.
In addition, the primary windings 4A, 4B and the secondary windings 7A, 7B
As shown in the cross-sectional structure diagram in Fig. 3, the arrangement of
These strands are wound in the same layer on the outer periphery of the magnetic core 3 so that they are arranged next to each other every turn (hereinafter referred to as side winding), and the other primary windings 5 and 6 are I try to wrap it around the outside.

As described above, according to this embodiment, the off-gate primary windings 4A, 4B and the corresponding secondary windings 7
Since the numbers of turns A and 7B are equal and they are side-wound, the leakage magnetic flux between the primary and secondary is significantly reduced, and the leakage inductance can be minimized. As a result, even if the capacitance is increased, the steepness of the rise of the off-gate current can be increased, and the arc extinction characteristics of the GTO are improved.

Furthermore, according to this embodiment, two GTO1A,
The two secondary windings 7A and 7B corresponding to 1B are
Since the two secondary windings 7A,
7B can be excited simultaneously. Therefore, the GTOs 1A and 1B can be driven in synchronization. Similarly, by winding multiple pairs of primary and secondary windings around a single magnetic core, it is possible to synchronize the on/off control of each GTO in which multiple GTOs are connected in parallel or in series. GTO damage caused by this can be prevented. Moreover,
Since multiple sets of secondary windings are wound around the same magnetic core, the pulse transformer can be made smaller. In particular, in the case of a GTO device consisting of a large number of GTOs, the number of pulse transformers can be significantly reduced, so the entire gate circuit can be significantly downsized.

Generally, the high main circuit voltage (e.g. 750V to 1500V) of GTO 1A or 1B is applied between the primary and secondary windings of the pulse transformer, so the windings should be coated with an insulation coating with sufficient dielectric strength. Bare wire must be used. However, in order to reduce the leakage inductance by reducing the gap between the primary and secondary windings, it is desirable to make the insulation coating as thin as possible. An example of a wire that meets these requirements is Poly-tetra-fluore PTFE (Poly-tetra-fluore-PTFE), which has excellent high pressure resistance and corona resistance.
ethylene) electric wire - manufactured by Junkosha.

Next, FIG. 4 is a plan view of the external structure of the above embodiment, and FIG. 5 is a sectional view taken along the arrow XX in FIG. 4. As shown in FIGS. 4 and 5, the entire pulse transformer is covered with a molded insulating material 8. As shown in FIGS. The primary winding is lead wire 9
Accordingly, the first characteristic structure is that the secondary winding has a lead-out structure that is connected to an external circuit or the like through a screw terminal 10. In addition, the second characteristic structure includes two secondary windings 7A and 7, as shown in FIG.
B are arranged symmetrically, each winding start is on the terminal S ₁ and S ₃ side, and the windings are wound in opposite directions.

That is, by making the primary side have a lead wire structure, the primary side can be pulled out all at once, the space for the pullout part is reduced, and the screw terminal 10
(high voltage side) without considering the edge surface distance.
Insulation between them can be easily ensured. As a result, the overall size can be reduced compared to a case where all the drawers have a screw terminal structure. In addition, the above-mentioned Jiyun front is attached to lead wire 9.
Using PTFE wire can further improve insulation reliability.

Now, let us consider a case where the secondary side has a lead wire structure. As the number of parallel divisions of the secondary winding increases, the number of lead wires that come out of the secondary winding increases, making the insulation process more complicated. Furthermore, connections with external circuits may become complicated and cause incorrect wiring. On the other hand, if the lead wires are connected in parallel inside the pulse transformer and then pulled out, the insulation of the connection part will have to be treated more often and the work will be complicated, which will reduce the insulation reliability of the connection part. It has the disadvantage of being stored away.

In addition, due to the above-mentioned second characteristic structure, that is, the symmetrical arrangement of the secondary windings, the secondary windings 7A, 7B
The leakage inductance of can be equalized,
It is possible to further synchronize GTO on/off control. Moreover, since the screw terminals 5 are arranged symmetrically, the length of the connection wiring with the GTO can be made equal and the wiring inductance can also be made equal, and the synchronization of the GTO on/off control can be further achieved.

〔Effect of the invention〕

As explained above, according to the present invention, the number of turns of the primary winding and the secondary winding are made equal and they are side-wound, so that the inductance is significantly reduced and the steepness of the gate current is improved. It has the effect of

Further, according to the present invention, a plurality of pairs of one
Since the secondary and secondary windings are wound, the on/off control of a plurality of GTOs can be easily synchronized, and furthermore, it is possible to reduce the size.

[Brief explanation of drawings]

Fig. 1 is a connection configuration diagram of a pulse transformer winding and a GTO gate circuit according to an embodiment of the present invention, Fig. 2 is a detailed configuration diagram of the winding of the embodiment, Fig. 3 is a cross-sectional structural diagram of the embodiment, and Fig. 4 The figure is a plan view showing the external shape of the embodiment.
The figure is a sectional view taken along the line XX in FIG. 4. 2...Pulse transformer, 3...Magnetic core, 4,4
A, 4B...Primary winding for off-gate, 7, 7A,
7B...Secondary winding.

Claims (1)

[Claims] 1. In a pulse transformer inserted and connected between a gate pulse generation circuit and a gate of a gate turn-off type thyristor, a primary winding for an off-gate to which an off-gate pulse is applied is connected to the gate. The number of turns of the off-gate primary winding and the secondary winding are made equal, and the strands of the off-gate primary winding and the secondary winding are wound in the same layer and adjacent to each other for each turn, and the secondary winding is wound as required. A pulse transformer characterized by being divided into multiple parts according to current capacity and connected in parallel. 2 In the invention described in claim 1,
A pulse transformer characterized in that a plurality of pairs of off-gate primary windings and secondary windings are wound around the same magnetic core. 3 In the invention described in claim 2,
A pulse transformer characterized in that the plurality of pairs of off-gate primary windings and secondary windings are wound symmetrically.