JPH0342810A - Pulse transformer - Google Patents

Abstract

PURPOSE:To obtain a pulse transformer for achieving a compact and high-frequency pulse by constituting the winding of the transformer using a coaxial cable and by dividing the outer side conductor of this coaxial cable equally and connecting in parallel for forming a primary winding. CONSTITUTION:A coaxial cable 30 where an outer-side conductor 31 and a central conductor 32 are insulated by polyethylene vinyl is wound around a core 20 and the outer-side conductor 31 is cut off at 1/2 the total winding. This cut-off outer-side conductor 31 is connected in parallel, a winding-start side and winding-end side are set to a (u) and (v) terminals, respectively, which are connected to a pulse power supply 40. If current flowing from this pulse power supply 40 to the terminals (u) and (v) is set to I1, current which flows to the outer-side conductor 31 becomes I1/2 so that apparent primary winding becomes the same as a secondary winding but the actual ratio of winding becomes 1:2, which is a boost-type transformer.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to pulse transformers.

(Prior art) Conventionally, in order to obtain a large pulse-like current, a method has been used to open and close the circuit of a capacitor charged to a high voltage. etc. have been used. However, these thyratrons and gas gaps have short lifespans because their electrodes wear out due to arcing during discharge, so semiconductor devices are used instead, but these semiconductor devices have a higher withstand voltage than thyratrons and gas gaps. Since the value is low, it is necessary to step up the voltage with a high voltage pulse transformer.

FIG. 3 is a diagram showing an example of a pulse switching circuit using a semiconductor element. After the capacitor 1 is charged by the DC power supply 4 with the semiconductor switch 1O in the off state, the semiconductor switch 1G is turned on and the charge on the capacitor 1 is is discharged, and the capacitor 2 is charged by the pulse current flowing to the secondary side of the pulse transformer 3. And this charge is
For example, it is used to excite laser gas in gas laser equipment or to imitate pulsed magnetic fields.

By the way, the pulse output in this manner requires a high frequency of the pulse that charges the capacitor 2, and in FIG. 3, this frequency is f. However, Ls: Leakage inductance of the pulse transformer 3 seen from the secondary side of the pulse transformer 3 C1: Capacitance of the capacitor 1 converted to the secondary side of the pulse transformer 3 C2: Capacitance of the capacitor 2 Since the resistance is normally set to C,=C2, it becomes as follows.

Therefore, in order to increase the frequency f0 of the output pulse, it is necessary to reduce Lm or C, C2, but since reducing the latter C1 and C2 reduces the output, it is necessary to reduce the former L3.

FIG. 4 shows a partial sectional view of a winding of a conventional pulse transformer.

In the figure, a low-voltage winding 21 and a high-voltage winding 22 are wound around insulating tubes 23A and 23B having different diameters, respectively, and are inserted into the iron core 20.

(Problem to be solved by the invention) However, in the pulse transformer 3 having such a configuration,
The leakage inductance L3 of the pulse transformer 3 greatly influences the stacked pressure of the windings, the number of turns (9 turns in diameter), and the distance d between the high and low voltage windings 21 and 22.

However, in the conventional pulse transformer 3, the spacing d is
．． There is a limit due to the dielectric strength between the two.

Therefore, if multiple transformers are connected in parallel, the external size will increase.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pulse transformer that is small and can generate high-frequency pulses.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides a pulse transformer that boosts a pulse voltage applied to the negative side, in which the winding of the transformer is configured with a coaxial cable, The outer conductor of this coaxial cable is divided into a plurality of equal parts and connected in parallel to form a primary winding, thereby reducing leakage inductance and producing a compact pulse transformer that can output high-frequency pulses.

(Embodiment) Hereinafter, one embodiment of the pulse transformer of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a pulse transformer in which windings are wound around an iron core 20 with a turns ratio of 1:2 between primary and secondary coils.

That is, in FIG. 1, the iron core 20 has an outer conductor 31.
A coaxial cable 30 with a center conductor 32 insulated with polyethylene vinyl is wound, and the outer conductor 31 is cut at one-half of the total number of turns.The cut outer conductors 31 are connected in parallel, and the winding start side is connected to a pulse power source (not shown) as a U terminal on the low voltage side, and as a V terminal on the winding end side. The center conductor 32 has a U terminal on the winding start side and a V terminal on the winding end side connected to a secondary side capacitor (not shown).

FIG. 2 shows the connection diagram of FIG.

In Figure 2, if the power flowing from the pulse power source 40 to the terminals u and v is 11, the current shunted to the outer conductor 31 is 11/2, so the apparent primary winding is the same as the secondary winding. In reality, it is a step-up transformer with a turns ratio of 1:2.

In this pulse transformer, since the same magnitude of current flows through the center conductor 32 and outer conductor 31 of the coaxial cable 30, the magnetic flux is completely canceled out, and as a result, the leakage magnetic flux is reduced, so the leakage inductance is extremely low. becomes smaller.

Further, since an insulating tube as in the conventional case is not required, a pulse transformer that is small and can obtain high-frequency pulses can be provided.

In the above embodiment, the step-up ratio is 1:2, but the step-up ratio can be further increased by increasing the number of parallel outer conductors 31.
Since it is only necessary to wind 0, it is possible to obtain a reliable pulse transformer that is easy to manufacture and has a reduced number of parts.

Further, in the above embodiment, when the secondary voltage is high, the coaxial cable 30 may be vacuum impregnated with, for example, a synthetic boxy resin after being wound.

[Effects of the Invention] As described above, according to the present invention, in a pulse transformer that boosts the pulse voltage applied to the negative side, a coaxial cable is wound around the iron core of the transformer, and the outer conductor is divided into a plurality of parts. Since the parallel windings are used, a pulse transformer with small leakage inductance and capable of outputting high-frequency pulses can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the pulse transformer of the present invention, FIG. 2 is a connection diagram showing the operation of the pulse transformer of the present invention,
FIG. 3 is a connection diagram showing a conventional pulse transformer, and FIG. 4 is a partially detailed diagram showing the operation of the conventional pulse transformer.

Claims (1)

[Claims] In a pulse transformer that boosts the pulse voltage applied to the primary side, the winding of the pulse transformer is composed of a coaxial cable, and the outer conductor of the coaxial cable is divided into a plurality of equal parts and paralleled. A pulse transformer characterized in that it is connected to a primary winding.