JP2001327177A - Voltage boosting circuit and pulse power circuit using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulse power circuit capable of generating a high voltage pulse even if a power source voltage is low. SOLUTION: This voltage boosting circuit comprises transmission line transformers PT1, PT2 in which two windings are wound in the same direction on a core for forming a closed magnetic path. In this case, primary side terminals of the transformers are connected in parallel with a power source and secondary side terminals of the transformers are connected in series with the power source. A primary side of the boosting circuit has a charging resistor R1, a capacitor C1, an SI thyristor 13, and a controller 12 for supplying a trigger signal for switching to the thyristor. A secondary side of the boosting circuit has capacitors C2, C3 connected to two secondary side terminals of the respective transformers and a pulse shaping circuit 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a voltage booster circuit and a pulse power circuit using the same.

[0002]

2. Description of the Related Art A laser device, a pulsed ion source, a plasma power supply and a dust collector require a pulse power circuit for handling high-voltage pulses. An electron tube has been used in this type of pulse power circuit.

[0003] A conventional pulse power circuit using an electron tube will be described with reference to FIG. Here, a case where the generated high voltage pulse is discharged between the electrodes in the discharge generating container will be described as an example.

A charge is stored in a capacitor C1 from a DC power supply 41 through a charging resistor R1. Next, a trigger signal sig is sent from the controller 42 to the thyratron 43. The thyratron 43 receiving the trigger signal sig conducts, and the electric charge of the capacitor C1 is changed to a pulse shaping circuit (PFN).
The high voltage pulse is guided to 44 and is generated. The high voltage pulse is applied to the electrodes in the discharge generating container 45 to generate a discharge.

[0005]

The conventional general pulse power circuit has the following problems.

[0006] 1. Since a conventional general pulse power circuit directly switches a voltage required as an output voltage, it is necessary to increase the power supply voltage as the output voltage increases. In this case, a switching element having a high withstand voltage is required, but at present, there is no semiconductor switching element having a withstand voltage equivalent to that of an electron tube for high voltage.

[0007] 2. The electron tube used in the pulse power circuit has a filament or a heater for the reason of the operation principle, and in the case of a medium-sized or larger electron tube, it takes about 10 minutes or more from when energized to when the tube becomes operable. is there.

[0008] 3. At present, many electron tubes are already replaced by semiconductor devices. Relatively special electron tubes such as thyratrons and ignitrons used in pulse power circuits may not be manufactured in the future due to the small amount used and limited manufacturers.

It is an object of the present invention to provide a pulse power circuit that can generate a high-voltage pulse even when the power supply voltage is low.

Another object of the present invention is to provide a voltage booster circuit suitable for the above-mentioned pulse power circuit.

[0011]

According to the present invention, a plurality of transmission line transformers each having two windings wound in the same direction are used for a core forming a closed magnetic circuit, and the primary terminal of each transmission line transformer is The power supply is connected in parallel, the secondary terminals of each transmission line transformer are connected in series, and a capacitor is connected between the two secondary terminals of each transmission line transformer. A voltage booster circuit is provided.

According to the present invention, a plurality of transmission line transformers each having two windings wound in the same direction on a core forming a closed magnetic circuit are used, and the primary terminal of each transmission line transformer is connected in parallel to the power supply. And a secondary terminal of each transmission line transformer is provided with a voltage booster circuit connected in series, and on the primary side of the voltage booster circuit, a charging resistor serially connected to the power supply, A capacitor connected in parallel to the power supply via a resistor, and a semiconductor switching element connected between one end of the charging resistor opposite to the power supply and one of primary terminals of the transmission line transformers And a controller for supplying a trigger signal for switching to the semiconductor switching element. The secondary side of the voltage booster circuit is connected between two secondary terminals of each transmission line transformer. And capacitor, the pulse power circuit; and a pulse shaping circuit is provided.

Preferably, an SI thyristor is used as the semiconductor switching element.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is characterized in that a transmission line transformer is used in a voltage boosting circuit so that a low power supply voltage is sufficient. First, referring to FIG. Will be described.

In FIG. 2A, a transformer PT in which two windings L1 and L2 are wound around a core 21 in the same direction is called a transmission line transformer. The core 21 is, for example, a ring-shaped closed core, and a plate-like conductor is used for the windings L1 and L2, for example. The magnitudes of the currents flowing through the respective windings L1 and L2 of the core 21 are equal to each other at I1, and since the directions are opposite, the generated magnetic fluxes cancel each other out and do not generate a magnetic flux in the core 21. Therefore, there is no action as a core, and the winding L
1 and L2 only, the power on the primary side is all transmitted to the secondary side, and the transmission efficiency is high.

In FIG. 2B, when there is a potential E2 on one side of the transmission line transformer, a current I2 due to this voltage flows in a loop formed by the winding of the core 21 and the ground. The inductance by the core 21 enters into the loop. Here, if the core 21 is appropriately selected, a large inductance can be obtained. Due to this inductance, a blocking impedance is generated in the loop, and no influence is exerted on the primary side. This is called input / output separation or isolation.

In FIG. 2C, transformers PT1 and PT2 having the same structure are used, and respective inputs are connected in parallel.
When the outputs are connected in series, the potential difference between the input and output of the transformer PT2 is zero, but the potential on the output side of the transformer PT1 is increased by E. However, the circuit operates well due to the isolation of the transmission line.

Here, the degree of separation between input and output will be described.

The blocking impedance depends on the inductance and frequency of the winding, and the input / output isolation is related to the blocking impedance, the signal source impedance and the load impedance.

The isolation is as follows.

In FIG. 2D, when there is no transmission line transformer and no blocking impedance, the output power is as shown in FIG.
Referring also to (a), it is represented by the following equation. Assuming that both the input impedance and the output impedance are R and the output power consumed by the load (the power transmitted to the load) is P2, E ′ = (（) E P2 = (E ′) ² / R = ｛( ^{1/2) E} 2 / R =} E 2
/ 4R In FIG. 2E, the output power P1 when there is a transmission line transformer and there is a blocking impedance XL is shown in FIG.
Referring also to (b), it is represented by the following equation.

E ′ = {R / (2R + XL)} E P1 = (E ″) ² / R = {RE · (2R + XL)} ²
/ R where XL = ωL Isolation (dB) is ₁₀ log ₁₀ (P1 / P2) = ₁₀ log ₁₀ ｛RE /
(2R + XL)｝ ² .

By appropriately selecting the core and increasing the isolation, a transformer with high transmission efficiency can be manufactured.

Next, an embodiment of the pulse power circuit according to the present invention will be described with reference to FIG. Here, SI (Static Ind.) Is used as the semiconductor switching element.
A pulse power circuit using a thyristor and a voltage boosting circuit combining two transmission line transformers as described above will be described. Further, a case where the generated high voltage pulse is discharged between the electrodes in the discharge generating container will be described as an example.

In FIG. 1, two transmission line transformers (PT1, PT2) described in FIG. 2 are used. As described above, the primary sides of the respective transformers PT1 and PT2 are connected in parallel, and the secondary sides are connected in series. On the primary side, a capacitor C1 is connected in parallel to the DC power supply 11 via a charging resistor R1. The DC power supply 1
The anode of the SI thyristor 13 is connected to one end of the charging resistor R1 on the side opposite to 1, and the cathode of the SI thyristor 13 is connected to one terminal on the primary side of the transformers PT1 and PT2. The controller 12 is connected to the gate of the SI thyristor 13.

On the other hand, on the secondary side of the transformers PT1 and PT2, capacitors C2 and C3 are connected between two output terminals, respectively, and further, an electrode in the discharge generating vessel 15 is connected via a pulse shaping circuit (PFN) 14. Have been.

The operation of this circuit is as follows. The charge is stored in the capacitor C1 through the charging resistor R1. Next, a trigger signal sig is sent from the controller 12 to the SI thyristor 13. S receiving the trigger signal sig
The I-thyristor 13 conducts, and the electric charge of the capacitor C1 is transferred through the transformers PT1 and PT2 to the capacitors C2 and C2.
Then, a pulse having a voltage E equal to the power supply voltage from the DC power supply 11 is generated on the secondary side of each transformer.

Since the secondary sides of the transformers PT1 and PT2 are connected in series, a pulse of a voltage 2E twice as large as the power supply voltage E can be obtained on the secondary side. The pulse of the voltage 2E thus obtained is further applied to the pulse shaping circuit 1
4 and a high-voltage pulse shaped by the pulse shaping circuit 14 is generated. The high voltage pulse is applied to the discharge vessel 15
A discharge is generated by being applied to the internal electrodes.

In the above example, two transmission line transformers are used. Similarly, three or more transmission line transformers are used, and the primary side is connected in parallel and the secondary side is connected in series. It can be easily understood that a high voltage pulse of three times or more of the power supply voltage can be obtained.
It is also clear that the semiconductor switching elements are not limited to SI thyristors.

The pulse power circuit according to the present invention is widely applied to circuits requiring high-voltage pulses, such as a laser device, a pulse ion source, a plasma power supply, and a dust collector. .

[0031]

According to the present invention, the following effects can be obtained.

1. Since a conventional general pulse power circuit directly switches a high voltage required at an output, the power supply voltage needs to be increased as the voltage on the output side increases. On the other hand, in the present invention, the power supply voltage can be reduced by the ratio of boosting by the transmission line transformer.

2. The lower power supply voltage increases the degree of freedom in design, which is advantageous for the problem of high-voltage insulation and cost.

3. By reducing the power supply voltage, it becomes easy to replace a range that has been generally applied to an electron tube with a semiconductor element.

4. The transmission line transformer has extremely low inductance and can generate a high-voltage pulse with a fast rise time.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a pulse power circuit according to the present invention.

FIG. 2 is a diagram for explaining the operation of a transmission line transformer used in the present invention.

FIG. 3 is a diagram for explaining output power in FIGS. 2 (d) and 2 (e).

FIG. 4 is a circuit diagram showing an example of a conventional pulse power circuit.

[Explanation of symbols]

 11, 41 DC power supply 12, 42 Controller 13 SI thyristor 14, 44 Pulse shaping circuit 15, 45 Discharge generating vessel 43 Thyratron

Claims (3)

[Claims] 1. A plurality of transmission line transformers each having two windings wound in the same direction on a core forming a closed magnetic circuit, and a primary terminal of each transmission line transformer is connected in parallel to a power supply. The secondary terminal of the transmission line transformer is connected in series,
A voltage boosting circuit comprising a capacitor connected between two secondary terminals of each transmission line transformer. 2. A plurality of transmission line transformers each having two windings wound in the same direction on a core forming a closed magnetic circuit, and a primary terminal of each transmission line transformer is connected in parallel to a power supply. The secondary terminal of the transmission line transformer includes a voltage booster circuit connected in series, and the primary side of the voltage booster circuit includes a charging resistor connected in series to the power supply, and A capacitor connected in parallel with a power supply; a semiconductor switching element connected between one end of the charging resistor opposite to the power supply and one of primary terminals of the transmission line transformers; A controller for supplying a trigger signal for switching to the element; a capacitor connected between two secondary terminals of each transmission line transformer on a secondary side of the voltage booster circuit; Pulse power circuit; and a pulse shaping circuit. 3. The pulse power circuit according to claim 2, wherein an SI thyristor is used as said semiconductor switching element.