JPH08172018A - Pulse power source - Google Patents

Abstract

PURPOSE: To reduce the size of a pulse power source as a whole by reducing the size of a pulse transformer. CONSTITUTION: The pulse transformer of a pulse power source which is provided with the pulse transformer supplied with a single-direction pulse-like current so as to obtain a high-voltage large-current pulse has a third winding 14 wound around a core 13 in addition to a first winding l4 and second winding 11 and a direct current is supplied to the third winding l4 from a constant-current power source 2 through a choke coil 3. The executive operating magnetic flux density ΔB of the pulse transformer is increased by making the polarity of the direct current opposite to the direction of the magnetic flux generated by the pulse-like current flowing to the primary winding 11 . Since the magnetic flux density ΔB is proportional to the volt-time product of the core l3 , the cross-sectional area of the core 13 can be reduced and therefore, the size of the pulse transformer can be reduced by reducing the volume of the core 13 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse power source for generating short pulses of high voltage and large current, and more particularly to a pulse transformer.

[0002]

2. Description of the Related Art For a pulse power source such as pulse laser excitation, pulse plasma generation, pulse denitration equipment, etc., a discharge switch such as a thyratron switch or a triggertron switch is used to directly switch a high voltage and a large current to generate a pulse. There is a combination of the generated one and a saturable reactor that becomes a semiconductor switch and a magnetic switch.

FIG. 3 shows an example of a pulse power supply that combines a semiconductor switch, a saturable transformer, and a saturable reactor to obtain a high voltage and a large current by an LC inverting circuit.

The semiconductor switch SW is a first-stage switch having one semiconductor switching element, its gate control circuit, and a snubber circuit.

A pulse current I ₀ indicated by an arrow is generated by a first stage pulse generation circuit in which a pulse transformer PT, a first stage energy storage capacitor C ₀ and a high voltage DC power supply HDC are combined with a semiconductor switch SW.

A saturable transformer ST that performs boosting and magnetic pulse compression is connected to the secondary winding of the pulse transformer PT. The secondary winding of the saturable transformer ST is provided with a voltage doubler generation circuit composed of capacitors C ₁ and C ₂ and a reactor L.

Further, a series circuit of a saturable reactor SI ₂ and a peaking capacitor C _P is connected in parallel to both ends of a reactor L which is an output terminal of the voltage doubler generation circuit. Further, the capacitor C _P has a laser oscillator LH as a load.
Are connected in parallel.

At the start of pulse generation, the capacitor C ₀ is charged to a high voltage by the high voltage DC power supply HDC. After this charging, by turning on the semiconductor switch SW, the primary current I ₀ flows through the path of the capacitor C ₀ → the primary winding of the pulse transformer PT → the semiconductor switch SW.

For this current I ₀ , the pulse transformer PT
Then, the voltage is boosted in two steps by the saturable transformer ST, and an ultrashort pulse of high voltage and large current is supplied to the load through the voltage doubler generation circuit and the like.

[0010] Here, the pulse transformer PT is to obtain a trans-acting high frequency current than the transformer of the commercial frequency (50,60H _Z), since the eddy current loss increases in transformer using the core or the like, generally Typically, a low-loss core material is used, or an air-core transformer is used.

[0011]

In the conventional pulse power supply, the pulse transformer is used for high voltage / short pulse, and the wire diameter of the winding insulated with high withstand voltage is large. Therefore, the primary winding and the secondary winding are You cannot increase the number of turns for both wires. For this reason, in the step-up transformer, the primary winding is often limited to one turn in order to obtain a high step-up ratio.

On the other hand, the voltage-time product of the transformer is proportional to the cross-sectional area of the magnetic core and the number of turns. Therefore, the transformer for a pulse power supply that cannot take many turns has a large magnetic core.

As a result, the step-up ratio is restricted and the size of the transformer itself is increased.

It is an object of the present invention to provide a pulse power supply which can downsize the pulse transformer and downsize the entire apparatus.

[0015]

In order to solve the above-mentioned problems, the present invention provides a pulse power supply having a pulse transformer to which a unidirectional pulse current is supplied to obtain a high-voltage / high-current pulse. In the pulse transformer, a third winding is provided on the core in addition to the primary winding and the secondary winding, and the third winding of the pulse transformer has a magnetic flux direction opposite to that generated by the pulse current flowing through the primary winding. It is characterized in that a DC bias means for supplying a DC constant current having a directional polarity is provided.

[0016]

By applying a reverse DC bias current to the third winding, the magnetic flux density amount ΔB of the execution operation of the pulse transformer is increased.
To increase. Since this execution operation magnetic flux density amount ΔB is proportional to the voltage-time product of the core, the core cross-sectional area of the transformer can be reduced, and accordingly, the core volume can be reduced and the pulse transformer can be miniaturized.

[0017]

1 is a circuit diagram showing an embodiment of the present invention, showing a portion of the pulse transformer PT of FIG.

In the pulse transformer, the primary winding 1 ₁ and the secondary winding 1 ₂ are wound around the core 1 ₃ at a predetermined turn ratio, and the third winding 1 ₄ for passing a DC bias current is provided. wound on the core 1 _3.

[0019] winding 1 _4, a constant current is supplied through the choke coil 3 from the constant current source 2. The choke coil 3 is the one that exhibits a high impedance to a pulse current flowing through the primary winding 1 ₁ suppresses the pulse current flows into the winding 1 ₄ side of (energy leakage).

The polarity of the direct current flowing through the winding 1 ₄ is opposite to the direction of the magnetic flux (indicated by the arrow) generated by the pulse current supplied to the primary winding 1 ₁ .

The magnitude of the current is such that a magnetic flux larger than the coercive force of the core 1 ₃ is generated. For example, holding power 1
(A / m), passing a DC bias current of 1 (A) or the winding 1 ₄ that the through-type windings to toroidal core (1 turn) the outermost 1 (m).

The core 1 ₃ shape, a toroidal shape or a racetrack shape, further is in either of solenoids.
The material of the core 1 ₃ is the core of low loss and high magnetic permeability, is for example, iron-based amorphous, cobalt-based amorphous, iron-based ultracrystallite.

[0023] In the structure of this embodiment, pulse current unidirectional flows through the primary winding 1 _1. For this pulse current, flowing a reverse DC bias current to the winding 1 _4. As a result, as shown in FIG. 2A, the execution operation magnetic flux density amount ΔB becomes larger than that in the case of the conventional configuration shown in FIG.

[0024] Here, execution operation magnetic flux density amount ΔB is proportional to the voltage time product of the core 1 _3, it is possible to reduce the core area of the transformer, can be reduced resulting in the core volume.

Also, the squareness ratio (Br / Bs) is good (≈
1) When it is a core, it is possible to obtain about twice as much ΔB (= Br + Bs) by the DC bias current.

The pulse transformer of this embodiment is shown in FIG.
Not only the pulse power source having the configuration shown in (1) but also other pulse power sources using a pulse transformer, the same operational effect can be obtained.

[0027]

As described above, according to the present invention, in the pulse transformer, the core is provided with the third winding in addition to the primary winding and the secondary winding, and the third winding is provided with the primary winding. Since the configuration is such that a DC constant current whose polarity is opposite to the direction of the magnetic flux generated by the pulse current flowing through the line is supplied, the magnetic flux density amount ΔB of the operation of the pulse transformer can be increased and the core cross-sectional area of the transformer can be increased. The size of the pulse transformer can be reduced by reducing the size of the core and the core volume. As a result, the pulse power supply can be downsized.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a magnetization characteristic diagram in the case of applying a DC bias (a) and the conventional case (b).

FIG. 3 is a circuit example of a pulse power supply.

[Explanation of symbols]

SW ... Semiconductor switch ST ... Saturable transformer PT ... Pulse transformer 1 ₁ ... Primary winding 1 ₂ ... Secondary winding 1 ₃ ... Core 1 ₄ ... Third winding 2 ... Constant current power supply 3 ... Choke coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyoshi Hara 2-17 Osaki, Shinagawa-ku, Tokyo Incorporated company Meidensha

Claims (1)

[Claims] 1. A pulse power supply for obtaining a high-voltage / large-current pulse by having a pulse transformer to which a unidirectional pulse current is supplied, wherein the pulse transformer has a core, in addition to a primary winding and a secondary winding. A third winding is provided, and the third winding of the pulse transformer is provided with DC bias means for supplying a DC constant current having a polarity opposite to the direction of the magnetic flux generated by the pulse current flowing in the primary winding. A pulse power supply characterized by that.