JPH0683035B2 - Pulse generator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pulse generator suitable for use as a power source of a pulse laser such as an excimer laser or a carbon dioxide gas laser.

[Prior Art] FIG. 3 is a circuit diagram showing a conventional pulse generator using a two-stage magnetic pulse compression circuit shown on page 57 of Optronics (1983) No. 12, for example. Reference numeral (1) is a charging resistor. One end of the charging resistor (1) is connected to the high-voltage power supply terminal + HV, and the other end is grounded via a switch element such as a thyratron (2). (3) is a charging capacitor, one end of which is connected to the connection point between the charging resistor (1) and the thyratron (2), and the other end is connected to the reactor (7) and the pulse. It is grounded via a series circuit composed of a compression capacitor (4). (8) is a saturable reactor for magnetic pulse compression. One end of this saturable reactor (8) is connected to the connection point of the reactor (7) and the pulse compression capacitor (4), and the other end is pulse compressed. It is grounded via the capacitor (5). (9) is a saturable reactor for magnetic pulse compression. One end of this saturable reactor (9) is connected to the connection point of the saturable reactor (8) and the pulse compression capacitor (5), and the other end is It is grounded via a pulse compression capacitor (6). A laser oscillator (10) and a charging reactor (11) are connected in parallel between both ends of the pulse compression capacitor (6).

The conventional pulse generator is configured as described above, and its operation will be described in detail below. FIG. 4 is a waveform diagram showing the voltage and current of each part during the operation of the conventional pulse generator. In FIG. 3 and FIG. 4, first, a voltage V ₀ = V is applied between the high voltage power supply terminal + HV and the ground, and the charging resistor (1), the charging capacitor (3), the reactor (7), saturable reactor (8), (9), passing a current through the charging reactor (11), for charging the charging capacitor (3) to a predetermined voltage V ₁ = -V. in this case,
Since the charging capacitor (3) is slowly charged,
Almost no voltage is applied to the reactor (7), saturable reactors (8) and (9), and charging reactor (11).

Next, when the thyratron (2) is ignited at time t ₀ , the loop of the charging capacitor (3), the thyratron (2), the pulse compression capacitor (4) and the reactor (7) is timed.
t conducting width from ₀ to time _{t 1 τ 1 (= t 1} -t 0), the peak value Ip ₁
Pulse current I ₁ flows through the capacitor for pulse compression (4)
A pulse voltage V ₂ is generated at. At time t ₁ , when the pulse current I ₁ becomes zero and the pulse voltage V ₂ reaches the peak value −Vp ₂ , the time t 1
Voltage-time product of pulse voltage V ₂ from ₀ to time t ₁ As a result, the saturable reactor (8) is saturated and the impedance becomes low. As a result, the current width τ ₂ (= t ₂ −t ₁ ), peak value Ip in the loop of the pulse compression capacitors (4) and (5) and the saturable reactor (8) from time t ₁ to time t _2.
2 of the pulse current I ₂ flows, the pulse voltage V ₃ generated pulse compression capacitor (5). Pulse compression capacitors (4), (5), saturated saturable reactor (8)
The loop inductance of the charging capacitor (3),
Thyratron (2), pulse compression capacitor (4),
Since it is set smaller than the inductance of the reactor (7) loop, the pulse current I ₂ has a larger peak value (Ip ₂ <Ip ₁ ) and a smaller conduction width (τ ₂ <than the pulse current I ₁ τ ₁ ), that is, the first-stage pulse compression is performed.

Then, the pulse current I ₂ at time t ₂ becomes zero, the pulse voltage V ₃ is the peak value applied to the pulse compression capacitor (5) -
When Vp ₃ is reached, pulse voltage V ₃ from time t ₁ to time t ₂
Voltage-time product As a result, the saturable reactor (9) is saturated and has a low impedance. As a result, the pulse compression capacitors (5) and (6) and the saturable reactor (9) have a pulse with a conduction width τ ₃ (= t ₃ −t ₂ ) and a peak value Ip ₃ in the loop from time t ₂ to t _3. A current I ₃ flows and a pulse voltage V ₄ is generated in the pulse compression capacitor (6). The inductance of the loop of the pulse compression capacitors (5) and (6) and the saturated saturable reactor (9) is greater than the inductance of the loop of the pulse compression capacitors (4) and (5) and the saturated saturable acrylic (8). Since the pulse current I ₃ has a larger peak value (Ip ₃ > Ip ₂ ) and a smaller conduction width (τ ₃ <τ ₂ ), the pulse current I ₃ is smaller than the pulse current I ₂ .
That is, the second-stage pulse compression is performed.

Finally, when the pulse current I ₃ becomes zero at time t ₃ and the pulse voltage V ₄ applied to the pulse compression capacitor (6) reaches the peak value −Vp ₄ , the peak value −Vp ₄ changes to the laser oscillator (10 Since the breakdown voltage between the pair of electrodes provided in () is set to be equal, glow discharge occurs between the electrodes.
As a result, the pulse current I ₄ flows in the loop of the pulse compression capacitor (6) and the laser oscillator (10), and the electric energy accumulated in the pulse compression capacitor (6) is stored in the gas space inside the laser oscillator (10). It is injected and laser light is output.

[Problems to be Solved by the Invention] In the conventional pulse generator using the magnetic pulse compression circuit, the time t ₁ to the time t ₂ when the pulse compression of the first stage is performed.
At, the pulse current I ₁ flows in the opposite direction from time t ₀ to time t ₁ . As a result, only a part of the electric energy accumulated in the charging capacitor (3) is transferred to the laser oscillator (10), and the electric energy remaining in the charging capacitor (3) is finally transferred to the thyrotron (2) or Since it is consumed as a loss of each component of the pulse generator such as the saturable reactor (8), there is a problem that the efficiency of the pulse generator is reduced.

The present invention has been made to solve the above-mentioned problems, and is performed at time t ₁ when the pulse compression of the first stage is performed.
After that, the purpose is to prevent the reverse pulse current I ₁ from flowing and to obtain an efficient pulse generator.

[Means for Solving the Problem] The pulse generator according to the present invention provides a voltage-time product of a magnitude necessary for preventing saturation due to the voltage applied during the period in which the first-stage pulse compression is performed. It has a saturable reactor for blocking reverse current.

[Operation] In the present invention, the saturable reactor for reverse current blocking has a high impedance in a non-saturated state during the period in which the first-stage pulse compression is performed, so that the pulse current flows in the opposite direction. Prevent.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a circuit diagram showing an embodiment of a pulse generator according to the present invention. In the figure, (1) to (6) and (8) to (11) are exactly the same as the above conventional device.
(12) is a reverse current blocking saturable reactor, one end of which is connected to the other end of the charging capacitor (3) and the other end of which is connected between the pulse compression capacitor (4) and the saturable reactor (8). Connected to a point.

Next, the operation will be described. FIG. 2 is a waveform diagram showing the voltage and current of each part during the operation of the pulse generator according to the present invention. In FIGS. 1 and 2, first, a voltage V ₀ = V is applied between the high voltage power supply terminal + HV and the ground, and the charging resistor (1), the charging capacitor (3), the reverse current blocking saturable Reactor (12), Saturable reactor (8),
(9), current is passed through the charging reactor (11),
Charging charging capacitor (3) to a predetermined voltage V ₁ = -V. In this case, since the charging capacitor (3) is slowly charged, the reverse current blocking saturable reactor (1
2), saturable reactors (8), (9), and charging reactor (11) receive almost no voltage.

Next, when the thyratron (2) is ignited at time t ₀ , the thyratron (2) has a low impedance, and therefore the voltage V is applied to the saturable reactor (12) for reverse current blocking which has a high impedance in the unsaturated state. _SR is applied. Voltage-time product of V _SR applied to saturable reactor (12) for reverse current blocking Reaches a designed constant value at time t ′ ₀ , the reverse current blocking saturable reactor (12) saturates and becomes a low impedance. As a result, the charging capacitor (3), thyratron (2), condenser (4), the loop at time t of the reverse current blocking saturable reactor (12) _'0 from time t'
₁ to conducting width _{τ '1 (= t' 1} -t '0), the peak value I'
pulse current I ₁ of p ₁ flows, the pulse voltage V ₂ is generated in the pulse compression capacitor (4).

Next, when the pulse current I ₁ becomes zero at time t ′ ₁ and the pulse voltage V ₂ reaches the peak value −V′p ₂ , the voltage time of the pulse voltage V ₂ from time t ′ ₀ to time t ′ ₁ product As a result, the saturable reactor (8) is saturated and has a low impedance. As a result, in the loop of the pulse compression capacitors (4) and (5) and the saturable reactor (8), the conduction width τ ′ ₂ (= t ′ ₂ −t ′) from time t ′ ₁ to t ′ _2.
1), the peak value Ip _'2 of the pulse current I ₂ flows, the pulse voltage V ₃ generated pulse compression capacitor (5). Pulse compression capacitors (4), (5), saturated inductor of loop of saturable reactor (8), pulse charging capacitor (3), thyratron (2), pulse compression capacitor (4), saturated reverse Since it is set smaller than the loop inductance of the current blocking saturable reactor (12), the pulse current I ₂ has a larger peak value than the pulse current I ₁ (Ip ′ ₂ > I′p ₁ ) The width becomes smaller. (Τ ′ ₂ <τ ′ ₁ ), that is, the first-stage pulse compression is performed.

In this case, when the pulse current I ₁ becomes zero at time t ′ ₁ , the reverse current blocking saturable reactor (12) has a voltage of the opposite polarity to the voltage applied from the time t ₀ to the time t ′ _0. because There is a period applied to ₂ 'time t to _1' time t as indicated by hatching in FIG. 2, the reverse current blocking saturable reactor (12) immediately becomes non-saturation state at time t _'1.
As a result, the saturable reactor for reverse current blocking (12) has a high impedance, so the pulse current I ₁ is blocked and does not flow in the opposite direction. The reverse current blocking saturable reactor (12) is designed to have a voltage-time product larger than 1/2 Vτ ' ₂ . That is, ηΔBS ≧ 1 / 2Vτ ′ ₂ (where η is the number of windings, ΔB is the amount of change in magnetic flux density of the magnetic core,
Since S is designed as the effective cross-sectional area of the magnetic core), at the time t ′ ₁ when the electric energy stored in the pulse compression capacitor (4) in the first stage pulse compression is transferred to the pulse compression capacitor (5). It is possible to prevent the pulse current I ₁ from flowing in the opposite direction from to the time t ′ ₂ .

Next, the pulse compression of the second stage and the output of the laser light are performed, and these operations are the same as those of the conventional pulse generator.

[Effects of the Invention] As described in detail above, the present invention provides a saturable reactor for reverse current blocking having a voltage-time product of a magnitude necessary for preventing saturation while the first-stage pulse compression is performed. Since the pulse current is provided, it is possible to prevent the pulse current from flowing in the opposite direction while the first-stage pulse compression is being performed, so that an efficient pulse generator can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a pulse generator according to the present invention, FIG. 2 is a waveform diagram showing voltage and current for explaining the operation, and FIG. 3 is a conventional pulse generator. A circuit diagram and FIG. 4 are waveform diagrams showing voltages and currents for explaining the operation. In the figure, (2) is a thyratron, (4), (5),
(6) is a pulse compression capacitor, (8) and (9) are saturable reactors, and (12) is a reverse current blocking saturable reactor. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A switch element which is connected between both ends of a power source and which generates a pulse by switching, and which is electrically connected to this switch element and comprises a saturable reactor and a pair of capacitors. Is a pulse compression circuit that generates steeper pulses, and is inserted between this pulse compression circuit and the switch element, the saturable reactor is saturated, and the voltage applied during the period when pulse compression is performed, A pulse generator comprising: another saturable reactor having a voltage-time product of a magnitude necessary for preventing saturation.