JP6732615B2 - Pulse power supply - Google Patents

Description

The present invention relates to a power supply used for an accelerator or the like for accelerating a charged particle beam in a pulsed manner, and relates to a pulse power supply device having a plurality of stages of PFN (Pulse Forming Network).

In a high-energy charged particle accelerator exceeding 1 billion electron volts, the problem of activation of the material of the vacuum container and the like becomes serious due to the radiation generated by the collision of the charged particle beam with the wall surface of the vacuum container. In order to accurately maintain the trajectory of the charged particle beam, it is necessary to control the relative accuracy of the current value with respect to the electromagnet power source to a high accuracy of approximately 0.01% or less, and further to improve the accuracy as much as possible. There is a request.

FIG. 6 is a circuit diagram showing the configuration of a conventional pulse power supply device described in Patent Document 1. This pulse power supply device supplies a pulse current having a trapezoidal waveform to the circuit portion of the load electromagnet 10, and mainly includes the following four components. that is,
(1) A first-stage charging/discharging circuit 21, which comprises a series circuit of a first-stage capacitor C1 and a first-stage unidirectional switch S1, and is capable of discharging the charging power of the first-stage capacitor C1 to the circuit part of the load electromagnet 10,
(2) It is composed of a series circuit of a succeeding stage capacitor C2, a succeeding stage one-way switch S2, and a waveform adjusting coil L2, and is capable of discharging the charging power of the succeeding stage capacitor C2 to the circuit portion of the load electromagnet 10. Stage charging/discharging circuit 22,
(3) A charger 40 that charges the first-stage capacitor C1 and the subsequent-stage capacitor C2 and that can adjust the charging voltage setting value,
(4) Trigger control circuit 30 capable of adjusting the time difference between the respective trigger signals by sending the trigger signals independent of each other to close the one-way switch S1 of the first stage and the one-way switch S2 of the subsequent stage.
Is.

The circuit portion of the load electromagnet 10 includes an inductance component 11 and a resistance component 12. The first-stage charge/discharge circuit 21 is connected between both ends of the load electromagnet 10. The charge/discharge circuit 22 in the subsequent stage is also connected between both ends of the load electromagnet 10. That is, the charging/discharging circuit 21 in the first stage and the charging/discharging circuit 22 in the subsequent stage are connected in parallel to the load electromagnet 10. As the one-way switches S1 and S2, thyristors that automatically extinguish with the reversal of the current direction are used.

The trigger control circuit 30 includes a trigger timing adjusting circuit 31, a first-stage gate drive circuit 32, a first-stage pulse transformer 33 for closing the first-stage unidirectional switch S1, a subsequent-stage gate drive circuit 34, and a subsequent-stage one. It includes a subsequent pulse transformer 35 for closing the directional switch S2. When the trigger timing adjustment circuit 31 receives the excitation trigger signal Str from the timing system in the charged particle beam apparatus, the trigger timing adjustment circuit 31 causes a time difference T _S2 (several μ seconds to several tens of seconds) between the gate drive circuit 32 in the first stage and the gate drive circuit 34 in the subsequent stage. It is configured to send the trigger signals T1 and T2 in (μsec). The trigger timing adjustment circuit 31 first outputs the trigger signal T1 to the gate drive circuit 32 in the first stage, and outputs the trigger signal T2 to the gate drive circuit 34 in the subsequent stage after a predetermined time difference T _S2 .

The positive terminal of the output voltage variable type charger 40 is connected to the positive terminal of the first-stage capacitor C1 via the first-stage charging resistor R1, and the negative terminal of the capacitor C1 is connected to the negative terminal of the charger 40. There is. Further, the positive terminal of the charger 40 is connected to the positive terminal of the capacitor C2 in the succeeding stage through the charging resistor R2 in the succeeding stage, and the negative terminal of the capacitor C2 is connected to the negative terminal of the charger 40. .. D1 is a protection diode.

Next, the operation of the pulse power supply device configured as described above will be described with reference to FIG. FIG. 7 is a waveform diagram showing a voltage/current waveform of each part of a conventional pulse power supply device and a pulse current waveform flowing through a load electromagnet.

The capacitor C1 in the first stage and the capacitor C2 in the subsequent stage are charged to the same voltage by the charger 40.

Next, the trigger timing adjustment circuit 31 to which the excitation trigger signal Str is input, sequentially outputs the trigger signals T1 and T2 to the first-stage gate drive circuit 32 and the subsequent-stage gate drive circuit 34 with a predetermined time difference T _S2. ..

The gate drive circuit 32 of the first stage turns on the one-way switch S1 of the first stage at the input timing of the trigger signal T1. The gate drive circuit 34 of the succeeding stage turns on the one-way switch S2 of the succeeding stage at the input timing of the trigger signal T2 after the predetermined time difference T _S2 .

Hereinafter, the change in the waveform of the pulse current flowing through the load electromagnet 10 at the flat top portion F (see FIG. 7) will be described.

Regarding the influence of the change in the resistance value of the resistance component 12 of the load electromagnet 10, there is an idea that the peak value of the load electromagnet current i ₁₃ is compensated by increasing the charging voltage setting command signal given to the charger 40. However, there is a problem in that the inclination of the direction in which the current falls as the temperature rises increases, and the flatness of the current in the flat top portion F deteriorates. The resistance value of the resistance component 12 (including the resistance value of the power feeding cable) in the load electromagnet 10 varies with the temperature change, and causes a change in the current waveform in the flat top portion F.

Therefore, a trigger timing adjusting circuit 31 is provided which provides an adjustable time difference T _S2 for the two trigger signals T1 and T2. By adjusting the time difference T _{S2 so as} to increase as the temperature rises, the slope of the current in the flat top portion F is adjusted (corrected).

As shown in FIG. 7, for example, the voltage/current waveforms of various parts of the pulse power supply device and the pulse current waveforms flowing in the load electromagnet 10 are changed, and the resistance value of the circuit of the load electromagnet 10 is changed from 20 mΩ to 20.9 mΩ and 21.8 mΩ. The time difference T _S2 (described as “TS2” in FIG. 7(c)) of the timing of firing the one-way switch S2 in the subsequent stage is gradually increased from 0 μs to 2 μs and 4 μs at the same time. By gradually increasing the charging voltage of the charger 40 from 969.00 V to 971.56 V and 974.12 V, the change width of the pulse current waveform can be suppressed to 0.1 A or less. This corresponds to a ratio of about 0.003% to the reference value 3000 [A], which is a sufficiently small value (an example of operation).

As described above, in the conventional example shown in FIG. 6, the time difference T _S2 is increased as the charging voltage of the charger 40 is increased in accordance with the temperature increase, so that the current decrease due to the temperature increase is suppressed and the flat top is suppressed. The flatness of the current in the section F can be improved.

The conventional example shown in FIG. 6 has actually been developed through the following historical changes.

In the old way of thinking, the charging voltage for the capacitors C1 and C2 was only changed. In this case, it was considered possible to suppress the change in the peak value of the pulse current waveform (the peak value decreases due to the temperature rise).

However, since the charging voltage is simply adjusted, the change in the flatness of the current in the flat top portion F cannot be compensated. That is, the resistance value increases as the temperature rises, the inclination in the direction in which the current falls decreases, and the flatness of the current in the flat top portion F deteriorates.

In the conventional example shown in FIG. 6 described above, in order to suppress the change in the pulse current waveform due to the temperature change, as described above, the charging voltage for the capacitors C1 and C2 is changed and the one-way switches S1 and S2 are turned on. Adjust the time difference by giving it a time difference. As a result, as shown in FIG. 7C, as the current waveform changes from A→B′→C′, the above-mentioned two problems (decrease in peak value and deformation of current waveform itself (decrease of decrease gradient) Change).

JP, 2016-100680, A

However, in the conventional example shown in FIG. 6, in practice, the overall effects of the capacitance of the first-stage capacitor C1, the capacitance of the second-stage capacitor C2, the waveform adjusting coil L2, and the resistance component/inductance component of the wiring ( Due to the mutual interference effect), as shown in FIG. 8, a current (first stage current) i ₁₁ flowing in the first stage charge/discharge circuit 21 and a current (subsequent stage current) i ₁₂ flowing in the subsequent stage charge/discharge circuit 22 are A new problem has arisen in that each waveform is easily disturbed and the waveform symmetry and flatness of the current (combined current) i ₁₃ (=i ₁₁ +i ₁₂ ) flowing in the circuit portion of the load electromagnet 10 is adversely affected.

That is, as shown in FIG. 8, both the first-stage current i ₁₁ and the subsequent-stage current i ₁₂ are distorted (the symmetry is lost) as compared with the waveform of FIG. The waveform of the load electromagnet current i ₁₃ has a sharper rise in the first half and a slower fall in the latter half, and the symmetry is greatly impaired. That is, an ideal highly symmetric waveform that resembles a trapezoidal shape is greatly deformed, and the flatness is significantly reduced.

Incidentally, the flatness (flatness in the time width of 10 μs) in the case of FIG. 8 is calculated as follows.

The peak value of the load electromagnet current i ₁₃ is 21215 [A], and the timing of showing the peak value is 262.159 [μs]. The current drop value from the peak value to the current value corresponding to a 10 μs width of 5 μs before and after the peak value timing is 4.5 [A].

Therefore, the flatness is
4.5/21215=212×10−6=212 [ppm]
Becomes The smaller the flatness value is, the more preferable it is, and in recent years, in the most advanced pulse power supply device for a high energy charged particle accelerator, which exceeds 1 billion eV, 212 [ppm] is too large. There is a strong demand to make it smaller, that is, to further improve the flatness (to be half or less).

As a measure for improving the flatness, in the conventional example shown in FIG. 6, the time difference T _S2 , which is the delay time of the rising timing of the succeeding stage current i ₁₂ from the rising timing of the first stage current i ₁₁ , is adjusted, Compared with the case (2 [μs] and 4 [μs]), when the length was made much larger, for example, 60 [μs], the results shown in FIG. 9 were obtained. FIG. 10 clearly shows the difference between FIG. 9 and FIG.

In FIG. 8A, FIG. 9A, and FIG. 10A, the horizontal axis and the vertical axis coincide with each other. FIG. 10A shows a change from FIG. 8A to FIG. 9A. In FIG. 10 (a), the first-stage current i _{11 (FIG. 8)} is the same as the first-stage current i ₁₁ in FIG. 8 (a), the first-stage current i ₁₁ of the first-stage current i _{11 (FIG. 9)} FIG. 9 (a) Is the same as. The waveforms related to FIG. 8A are indicated by thin lines, and the waveforms related to FIG. 9A are indicated by thick lines.

In FIG. 10A, the rising timing of the peak-shaped one-stage succeeding stage current i _{12 (FIG. 8)} indicated by the thin dotted line having a narrow interval is 0 [μs], while The rising timing of the peak-shaped succeeding stage current i _{12 (FIG. 9), which} is indicated by the thick dotted narrow line, is delayed, and the delay time is 60 μs. Further, the double-peaked first-stage current i _{11 (FIG. 8)} shown by the dotted thin lines with wide intervals shows a local minimum value near 370 [μs], but the change in the differential coefficient before and after that is continuous. Has become. That is, the waveform change is smooth. On the other hand, the mountain-shaped first-stage current i _{11 (FIG. 9)} indicated by the thick dotted lines with wide intervals has a 0 level near 300 [μs], and is 0 from around 300 [μs] to around 370 [μs]. The level continues and gradually rises from 0 level after 370 [μs]. That is, the first stage current i _{11 (FIG. 9)} has a discontinuous differential coefficient, and the smoothness in the waveform change is lost.

Next, the change from FIG. 8 to FIG. 9 in the first peak current i ₁₁ of the double peak shape and the change from FIG. 8 to FIG. 9 in the second peak current i ₁₂ of the single peak shape are compared. , The influence of the load electromagnet current i ₁₃ on the change from FIG. 8 to FIG. 9 will be examined.

In the range of approximately 130 to 300 [μs], the change from the thin-line first-stage current i _{11 (FIG. 8)} to the thick-line first-stage current i _{11 (FIG. 9)} is small (the displacement vector is downward), and the magnitude of the decrease is large. This is larger than the increase (the displacement vector is upward) from the subsequent current i _{12 (FIG. 8)} of the thin line to the subsequent current i _{12 (FIG. 9) of the} thick line. As a result, the thick line load electromagnet current i _{13 (FIG. 9)} shows a shape change that sinks below the thin line load electromagnet current i _{13 (FIG. 8)} in the range of approximately 60 to 300 [μs] _. There is. This is the waveform change in the first half.

In the range of approximately 400 to 600 [μs], the thin-line first-stage current i _{11 (FIG. 8)} increases to the thick-line first-stage current i _{11 (FIG. 9)} (displacement vector is upward). , From the thin-line succeeding stage current i _{12 (FIG. 8)} to the thick-line succeeding stage current i _{12 (FIG. 9)} . As a result, the thick line load electromagnet current i _{13 (FIG. 9)} shows a shape change that swells upward above the thin line load electromagnet current i _{13 (FIG. 8)} in the range of approximately 370 to 770 [μs] _. .. This is the waveform change in the latter half.

With respect to the load electromagnet current i ₁₃ , due to the synergistic effect of the sinking on the first half side and the swelling on the latter half side, as compared with the load electromagnet current i ₁₃ of the thin wire _{(FIG. 8)} , the load electromagnet current i _{13 of the} thick line _{(Fig. 9)} will have a shape closer to a highly symmetric waveform similar to a trapezoid.

However, it was found that the flatness of the load electromagnet current was worse when the rising timing was delayed by 60 [μs] than when it was delayed. This point will be described below with reference to FIGS. 8B, 9B, and 10B.

Regarding the scale of the scale, as described above, the horizontal axis and the vertical axis are the same in FIGS. 8(a), 9(a) and 10(a), while in FIG. 8(b). 9(b), the scale of the scale is different on the horizontal axis and the vertical axis. On the other hand, in FIG. 9B and FIG. 10B, the scale intervals are the same on the horizontal axis and the vertical axis, and the time axis is in the range of 230 to 380 [μs] (150 [μs] in total). The scale value is common, but the current axis has a different scale value. The time axis scale in FIG. 8B is in the range of 250 to 280 [μs] (30 [μs] in total), and the time axis scale in FIG. 9B is in the range of 230 to 380 [μs] (150 [all]. μs]). The latter has a finer scale. The current axis scale in FIG. 8B is in the range of 21.208 to 21.218 [kA] (0.01 [kA]=10 [A] in total), and the current axis scale in FIG. 9B is 20. The range is from 100 to 20.400 [kA] (total 0.3 [kA]=300 [A]). Again, the latter has a finer scale.

FIG. 10B shows a graph of the same scale on both the vertical and horizontal axes as in FIG. 9B, showing the load electromagnet current i _{13 (FIG. 9)} and the load electromagnet current i of FIG. 8B. i _{13 (FIG. 8)} . The current axis, which is the vertical axis, is a relative scale. This is intended to represent the shape change of the load electromagnet current i _{13 (FIG. 9)} and the load electromagnet current i _{13 (FIG. 8)} , and the absolute current value is irrelevant.

As is clear from FIGS. 8, 9 and 10, when the subsequent stage current i ₁₂ is delayed by 60 [μs] with respect to the initial stage current i ₁₁ and then started up, the initial stage current i ₁₁ is as shown in FIG. 9A. Becomes discontinuous with the 0 level continuing for a certain period of time, and as a result, the load electromagnet current i ₁₃ has a waveform similar to a trapezoid as a whole, as shown in FIGS. 9(a) and 10(a). Although it becomes closer to the highly symmetric waveform, as shown in the comparison between FIG. 8(b) and FIG. 9(b), or as shown in FIG. 10(b), it is discontinuous at the flat top portion F. It has a double-peaked waveform and the flatness is extremely deteriorated.

Regarding the waveform of the load electromagnet current i _{13 (FIG. 8)} in _{FIG. 10B} , the thick solid line portion is the load electromagnet in the range of approximately 256 to 268 [μs] shown in FIG. 8B. It corresponds to the current i ₁₃ . The thin broken line portion shows that the shape is a single mountain even if the range is widened.

The load electromagnet current i _{13 (FIG. 9) shown in FIG.} 10B when the succeeding stage current i ₁₂ is started up with a delay is a discontinuous two-peak waveform in which the differential coefficient changes from minus to plus at once. However, the range of the required instantaneous current value is deviated, and the trajectory of the charged particle beam cannot be held accurately.

The present invention was created in view of the above circumstances, and relates to a pulse power supply device, in which the waveform of the load electromagnet current is restored by deforming the waveform to a continuous waveform by eliminating discontinuities. The purpose is to further improve the flatness of the flat top portion while bringing the current into a highly symmetric waveform similar to a trapezoid.

The present invention solves the above problems by taking the following means.

<1> The first pulse power supply device according to the present invention is
A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A series circuit of a first-stage capacitor and a first-stage unidirectional switch, and a first-stage charging/discharging circuit capable of discharging the charging power of the first-stage capacitor to the circuit part of the load electromagnet,
A charging/discharging circuit of a succeeding stage, which comprises a series circuit of a capacitor of a succeeding stage, a one-way switch of the succeeding stage, and a waveform adjusting coil, and which can discharge the charging power of the capacitor of the succeeding stage to the circuit portion of the load electromagnet In addition to the above,
A charger that charges the first-stage capacitor and the subsequent-stage capacitor, and has a charge voltage setting value adjustable,
A pulse power supply device that sends trigger signals that are independent of each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and includes a trigger control circuit capable of adjusting the time difference between the trigger signals. And
A variable resistor is inserted in the charge/discharge circuit of the first stage, and a flat top portion of the trapezoidal waveform of the pulse current flowing in the circuit portion of the load electromagnet is discontinuous in that its differential coefficient changes from minus to plus. It is characterized in that the flatness at the flat top portion is improved by changing the shape from two chevrons to one continuous chevron and approaching a highly symmetrical waveform .

<2> The second pulse power supply device according to the present invention is
A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A series circuit of a first-stage capacitor and a first-stage unidirectional switch, and a first-stage charging/discharging circuit capable of discharging the charging power of the first-stage capacitor to the circuit part of the load electromagnet,
A charging/discharging circuit of a succeeding stage, which comprises a series circuit of a capacitor of a succeeding stage, a one-way switch of the succeeding stage, and a waveform adjusting coil, and which can discharge the charging power of the capacitor of the succeeding stage to the circuit portion of the load electromagnet In addition to the above,
A charger that charges the first-stage capacitor and the subsequent-stage capacitor, and has a charge voltage setting value adjustable,
A pulse power supply device that sends trigger signals that are independent of each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and includes a trigger control circuit capable of adjusting the time difference between the trigger signals. And
A one-way energization element is connected in antiparallel to the one-way switch of the first stage in the charge and discharge circuit of the first stage, and a flat top portion of the trapezoidal similar waveform of the pulse current flowing in the circuit portion of the load electromagnet, It is characterized by improving the flatness in the flat top part by changing from a discontinuous two-peak shape whose differential coefficient changes from negative to positive to one continuous peak shape and approaching a highly symmetrical waveform. To do.

<3> A third pulse power supply device according to the present invention comprises:
A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A series circuit of a first-stage capacitor and a first-stage unidirectional switch, and a first-stage charging/discharging circuit capable of discharging the charging power of the first-stage capacitor to the circuit part of the load electromagnet,
A charging/discharging circuit of a succeeding stage, which comprises a series circuit of a capacitor of a succeeding stage, a one-way switch of the succeeding stage, and a waveform adjusting coil, and which can discharge the charging power of the capacitor of the succeeding stage to the circuit portion of the load electromagnet In addition to the above,
A charger that charges the first-stage capacitor and the subsequent-stage capacitor, and has a charge voltage setting value adjustable,
A pulse power supply device that sends trigger signals that are independent of each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and includes a trigger control circuit capable of adjusting the time difference between the trigger signals. And
A variable resistor is inserted in the first-stage charging/discharging circuit, and a one-way conducting element is connected in antiparallel to the first-stage one-way switch in the first-stage charging/discharging circuit , and a circuit part of the load electromagnet is connected. The flat top part of the trapezoidal waveform similar to the pulse current flowing in is changed from the discontinuous two peaks whose differential coefficient changes from negative to positive to one continuous peak and close to the highly symmetrical waveform. In addition, the flatness of the flat top portion is improved .

<1A> In the pulse power supply device having the configuration of <1> above, the peak value and level of the first-stage current are controlled by adjusting the resistance value of the variable resistor inserted in the first-stage charging/discharging circuit. Eliminate the flat part found in the lower level part and adjust the whole waveform so that it changes smoothly. That is, the current waveform of the load electromagnet is changed from a discontinuous two-peak shape whose differential coefficient changes from negative to positive to one continuous peak shape so that the discontinuity of the waveform is eliminated and the entire waveform is Is recovered and transformed into a continuous one. This makes it possible to improve the flatness of the flat top portion while bringing the load electromagnet current, which is a combination of the initial stage current and the delayed subsequent stage current, into a highly symmetrical waveform similar to a trapezoid.

<2A> In the pulse power supply device configured as described above in <2>, the one-way energization element is connected in antiparallel to the first-stage one-way switch in the first-stage charge/discharge circuit. As a result, when the first-stage current that has risen once drops and approaches the lowest level, the first-stage current can proceed to the negative level due to the presence of the antiparallel one-way conducting element. That is, the limiting action with the lower limit of 0 level as in the case of the conventional example does not work. In this way, for the flat top part of the trapezoidal waveform of the pulse current flowing in the circuit part of the load electromagnet, the differential coefficient changes from the discontinuous two peaks that change from negative to positive to one continuous peak. Since the continuity at the lowest level of the initial stage current is restored, the load electromagnet current, which is the combination of the initial stage current and the delayed subsequent stage current, approaches the highly symmetric waveform similar to a trapezoid while maintaining its flat shape. It is possible to greatly improve the flatness of the top portion.

<3A> In the pulse power supply device configured as described above in <3>, the variable resistor is inserted in the charging/discharging circuit in the first stage, and the one-way conducting element is connected in antiparallel to the one-way switch in the first stage. .. This can further improve the flatness of the flat top portion.

The pulse power supply device of the present invention having the above configuration has the following preferable changes and modifications. That is, a unidirectional energization element is inserted between the connection point between the charge/discharge circuit of the first stage and the charge/discharge circuit of the subsequent stage and the load electromagnet in a direction from the connection point to the load electromagnet. It is an aspect that.

This makes it possible to ensure a smooth shift of the first stage current to a negative level.

According to the present invention, the trapezoidal shape of the pulse current flowing in the circuit portion of the load electromagnet is obtained by eliminating the discontinuity in the waveform of the load electromagnet current and increasing the adjusting elements for recovering and transforming the entire waveform into a continuous waveform. The flat-top part of the similar waveform is changed from the discontinuous two peaks whose differential coefficient changes from minus to plus to one continuous peak, and the load electromagnet current becomes a highly symmetrical waveform similar to a trapezoid. It is possible to improve the flatness in the flat top portion while sufficiently bringing them close to each other.

A circuit diagram showing a configuration of a pulse power supply device according to a first embodiment of the present invention. Waveform diagram showing a pulse current waveform flowing through each charge/discharge circuit and load electromagnet in the first stage and the subsequent stages of the pulse power supply device according to the first embodiment of the present invention. Circuit diagram showing a configuration of a pulse power supply device according to a second embodiment of the present invention. Waveform diagram showing a pulse current waveform flowing through each charge/discharge circuit and load electromagnet in the first stage and the subsequent stages of the pulse power supply device according to the second embodiment of the present invention. Circuit diagram showing a configuration of a pulse power supply device in a modification of the present invention Circuit diagram showing the configuration of a pulse power supply device in a conventional example Waveform diagram showing the voltage/current waveform of each part of the pulse power supply device and the pulse current waveform flowing through the load electromagnet in the conventional example Waveform diagram for pointing out the problems of the pulse power supply device in the conventional example Waveform diagram for pointing out the problems of the pulse power supply device in the conventional example Waveform diagram for pointing out the problems of the pulse power supply device in the conventional example

Hereinafter, the embodiment of the pulse power supply device of the present invention having the above configuration will be described in detail at the level of a specific example.

[First Embodiment]
FIG. 1 is a circuit diagram showing a configuration of a pulse power supply device according to a first embodiment of the present invention, and FIG. 2 is a waveform showing a pulse current waveform flowing in each charge/discharge circuit and a load electromagnet in the first and subsequent stages of the pulse power supply device. It is a figure.

In FIG. 1, 10 is a load electromagnet in the charged particle beam apparatus, 11 is an inductance component included in the circuit part of the load electromagnet 10, 12 is a resistance component included in the circuit part of the load electromagnet 10, and 21 is a first stage capacitor C1 and a first stage. A one-way switch S1 and a variable resistor VR1 are connected in series and connected to both ends of a load electromagnet 10 (a series circuit of an inductance component 11 and a resistance component 12). This is a charging/discharging circuit of the succeeding stage in which C2, the one-way switch S2 of the succeeding stage, and the waveform adjusting coil L2 are connected in series and connected across the load electromagnet 10. The variable resistor VR1 has a very small resistance value of several mΩ to several tens of mΩ, and is made of, for example, a copper bar or a cable, and the resistance value is adjusted. In the case of this embodiment, the number of stages of the charging/discharging circuit 22 in the subsequent stage is one. For the one-way switches S1 and S2, a thyristor that automatically extinguishes with the reversal of the current direction is used in this embodiment, but other control switching elements may be used.

In the first-stage charging/discharging circuit 21, the positive terminal of the first-stage capacitor C1 having the negative terminal connected to the load electromagnet 10 is connected to the positive terminal (anode) of the first-stage unidirectional switch S1 including a thyristor. The variable resistor VR1 is connected to the cathode terminal (cathode) of S1. Further, in the charging/discharging circuit 22 of the subsequent stage, the positive terminal of the capacitor C2 of the subsequent stage whose negative terminal is connected to the load electromagnet 10 is connected to the positive terminal (anode) of the one-way switch S2 of the subsequent stage formed of a thyristor. The waveform adjusting coil L2 is connected to the cathode terminal (cathode) of the one-way switch S2. One end of the variable resistor VR1 and one end of the waveform adjustment coil L2 are connected to each other, and the connection point is connected to the load electromagnet 10.

Reference numeral 30 is a trigger control circuit, 31 is a trigger timing adjustment circuit, 32 is a first stage gate drive circuit, 33 is a first stage pulse transformer for closing the first stage one-way switch S1, and 34 is a subsequent stage gate drive circuit. Reference numeral 35 is a pulse transformer of the succeeding stage for closing the one-way switch S2 of the succeeding stage. When the trigger timing adjustment circuit 31 in the trigger control circuit 30 receives the excitation trigger signal Str from the timing system in the charged particle beam apparatus, the time difference T _S2 (number) with respect to the gate drive circuit 32 in the first stage and the gate drive circuit 34 in the subsequent stage is calculated. It is configured to send the trigger signals T1 and T2 in (μsec to several tens of μsec).

The trigger timing adjustment circuit 31 first outputs the trigger signal T1 to the gate drive circuit 32 in the first stage, and outputs the trigger signal T2 to the gate drive circuit 34 in the subsequent stage after a predetermined time difference T _S2 .

Further, in FIG. 1, 40 is a charger whose output voltage is adjustable (variable output voltage type), D1 is a protection diode, and R1 and R2 are charging resistors. The protection diode D1 is connected across the charger 40. The positive electrode terminal of the charger 40 is connected to the positive electrode terminal of the first-stage capacitor C1 via the first-stage charging resistor R1, and the negative electrode terminal of the capacitor C1 is connected to the negative electrode terminal of the charger 40. Further, the positive terminal of the charger 40 is connected to the positive terminal of the capacitor C2 in the succeeding stage through the charging resistor R2 in the succeeding stage, and the negative terminal of the capacitor C2 is connected to the negative terminal of the charger 40. ..

The above configuration is characterized in that the variable resistor VR1 is inserted in the charge/discharge circuit 21 in the first stage in comparison with the conventional example shown in FIG. The insertion point of the variable resistor VR1 in the first-stage charging/discharging circuit 21 is between the waveform adjusting coil L2 and the first-stage one-way switch S1, and the first-stage capacitor C1 and the first-stage one-way switch S1. May be between.

Next, the operation of the pulse power supply device of this embodiment configured as described above will be described.

From the charger 40, the first-stage capacitor C1 is charged through the first-stage charging resistor R1 and the subsequent-stage capacitor C2 is charged through the subsequent-stage charging resistor R2. Both capacitors C1 and C2 are charged to the same voltage.

Next, when the excitation trigger signal Str generated at a predetermined timing in the timing system of the charged particle beam device is input to the trigger timing adjusting circuit 31, the trigger timing adjusting circuit 31 causes the gate driving circuit 32 in the first stage and the gates in the subsequent stages. The trigger signals T1 and T2 are sequentially sent to the drive circuit 34 with a predetermined time difference T _S2 .

The first-stage gate drive circuit 32 that receives the trigger signal T1 outputs a gate pulse to the first-stage unidirectional switch S1 via the first-stage pulse transformer 33 to turn on the first-stage unidirectional switch S1. Further, after a predetermined time difference T _S2 , the gate drive circuit 34 of the subsequent stage, which receives the trigger signal T2, outputs a gate pulse to the one-way switch S2 of the subsequent stage via the pulse transformer 35 of the subsequent stage, and The one-way switch S2 is turned on. The above-mentioned predetermined time difference T _S2 is opened between the turn-on timing of the first stage one-way switch S1 and the turn-on timing of the subsequent stage one-way switch S2.

The output timing of the excitation trigger signal Str to the trigger timing adjusting circuit 31 is determined as follows. In the charged particle beam apparatus, that is the timing at which the pulse current flowing through the load electromagnet 10 reaches a peak value at the timing when the charged particle beam, which is the target of the magnetic field, passes through the load electromagnet 10. That is, the flat top portion F (see FIG. 2) of the current waveform of the load electromagnet current i ₃ corresponds to the period in which the charged particle beam passes through the load electromagnet 10.

The change in the current waveform at the flat top portion F will be described below.

The resistance value of the resistance component 12 of the circuit portion of the load electromagnet 10 changes with a change in temperature, and causes a change in the current waveform in the flat top portion F. The resistance value of the resistance component 12 includes the resistance value of the cable for feeding the load electromagnet 10 from the pulse power supply device. As a power supply cable, a coaxial cable is usually used when transmitting a large amount of pulsed power, but a water-cooled conductor cannot be used in many cases from the viewpoint of insulation and cost, which causes a temperature rise. Particularly, in an accelerator application for accelerating a charged particle beam in a pulsed and intermittent manner, the conductor temperature may increase by several tens of degrees Celsius due to Joule heat due to an effective current. In such a case, the resistance value of the resistance component 12 increases by about 10%.

Regarding the influence of the change in the resistance value of the resistance component 12 of the load electromagnet 10, as explained as the problem in the conventional example, the peak of the load electromagnet current i ₃ is increased by increasing the charging voltage setting command signal given to the charger 40. There is an idea to compensate for the decrease in the value. However, there is a problem in that the inclination of the direction in which the current falls as the temperature rises increases, and the flatness of the current in the flat top portion F deteriorates.

Therefore, the trigger timing adjusting circuit 31 is provided with an adjustable time difference T _S2 with respect to the two trigger signals T1 and T2 for closing the first-stage unidirectional switch S1 and the subsequent-stage unidirectional switch S2, respectively. By adjusting (correcting) the slope of the current in the flat top portion F by adjusting the time difference T _S2 between T1 and T2 to increase as the temperature rises, an attempt is made to improve the flatness of the current in the flat top portion F. To be

However, as described in the section [Problems to be Solved by the Invention], the total influence of the capacitances of the capacitors C1 and C2 in the first stage and the subsequent stage, the resistance component and the inductance component of the waveform adjusting coil L2 and the wiring. Due to (mutual interference effect), even if the time difference T _S2 of the rising timings of the two trigger signals T1 and T2 is variously adjusted, the flatness of the current in the flat top portion F can be easily improved. There wasn't.

That is, although it is possible to make the waveform of the load electromagnet current i ₃ close to an ideal trapezoidal similar waveform (improve the symmetry between the first half and the second half), the strictness in the flat top portion F Observing such a waveform, the waveform of the first stage current i ₁ becomes discontinuous in its differential coefficient, and it spreads and the waveform of the load electromagnet current i ₃ also becomes a discontinuous two-peak shape in its differential coefficient. It caused an inconvenient situation (see FIGS. 8, 9 and 10).

On the other hand, in the first embodiment of the present invention, the variable resistor VR1 is inserted in the charging/discharging circuit 21 of the first stage to detect the differential coefficient in the waveform of the first stage current i ₁ causing the above-mentioned inconvenience. It is possible to eliminate the discontinuity (continuation of 0 level for a certain period of time) and make the waveform smooth.

2 (b) is an enlarged view of the vicinity of the flat-top portion F in FIG. 2 (a), 9 of the conventional case shown in FIG. 6, as compared with FIG. 10, continuous in the load electromagnet current i ₃ It is possible to recognize the improvement of the property and symmetry, and the improvement of the flatness.

That is,
(1) A configuration in which the charger 40 that charges the first-stage capacitor C1 and the subsequent-stage capacitor C2 is of a variable type in which the charging voltage setting value can be adjusted,
(2) A trigger control circuit 30 in which a time difference T _S2 of rising timing is provided between the two trigger signals T1 and T2 for the one-way switch S1 of the first stage and the one-way switch S2 of the subsequent stage, and the time difference T _S2 can be adjusted. Of the
(3) The degree of freedom in adjusting the waveform of the load electromagnet current i ₃ is increased by the above three configurations in which the variable resistor VR1 is inserted in the charge/discharge circuit 21 in the first stage.

As a result, the waveform of the load electromagnet current i ₃ is approximated to an ideal highly symmetrical waveform similar to a trapezoid (improving the symmetry between the first half and the second half), and the flat top portion F The waveform of the first-stage current i ₁ and the differential coefficient of the waveform of the load electromagnet current i ₃ are made strictly continuous (eliminating the discontinuous two-peak shape in the case of the conventional example), and the waveform of the load electromagnet current i ₃ is smoothed. It became possible to do it.

[Second Embodiment]
FIG. 3 is a circuit diagram showing a configuration of a pulse power supply device according to a second embodiment of the present invention, and FIG. 4 is a waveform showing a pulse current waveform flowing in each charge/discharge circuit and load electromagnet in the first stage and the subsequent stages of the pulse power supply device. It is a figure. In FIGS. 3 and 4, the same reference numerals as those used in FIGS. 1 and 2 of the first embodiment denote the same components, and detailed description thereof will be omitted.

The configuration of the second embodiment different from that of the first embodiment is as follows. That is, in the second embodiment, the first-stage charging/discharging circuit 21 is energized in antiparallel to the first-stage one-way switch S1 instead of the variable resistor VR1 in the first embodiment. The element D2 is connected. Here, a diode is used as the first unidirectional conducting element D2. The first unidirectional current-carrying element D2 is connected in anti-parallel to the first-stage unidirectional switch S1 because the anode of the diode D2 is connected to the cathode of the thyristor S1 and the cathode of the diode D2 is connected to the anode of the thyristor S1. It is being done.

Further, a second unidirectional energizing element D3 is inserted between the connection point between the first-stage unidirectional switch S1 and the waveform adjusting coil L2 and the input terminal of the load electromagnet 10. A diode is also used as the second one-way conducting element D3.

The first unidirectional conducting element D2 and the second unidirectional conducting element D3 have the following relationship. In the case of the first embodiment, it is not assumed that the succeeding stage current i ₂ output from the succeeding stage charge/discharge circuit 22 flows into the first stage charge/discharge circuit 21. This is reflected in that the lowest level of the dropping first stage current i ₁ is 0 level in FIGS. 9A and 10A.

On the other hand, in the second embodiment, by connecting the first unidirectional conducting element D2 to the unidirectional switch S1 of the first stage in reverse, the subsequent stage current i output from the charging/discharging circuit 22 of the subsequent stage. ₂ is about to flow into the charge/discharge circuit 21 of the first stage. That is, this is because the capacitor C1 in the first stage is reversely charged. As a result, the first-stage capacitor C1 is allowed to be charged and discharged with its high-side terminal on the low potential side and its low-side terminal on the high potential side. That is, it is possible to allow the first stage current i _{1 to} have a negative level.

The reason for inserting the second one-way conducting element D3 is that, as described above, the first-stage capacitor C1 in which the high-side terminal is on the low potential side and the low-side terminal is on the high potential side is This is to prevent the electric current from flowing to the electromagnet 10 in the direction opposite to the normal direction.

That is, in the present embodiment, the addition of the first one-way conducting element D2 allows the shift of the first stage current i _{1 to} the negative level, while the addition of the second one-way conducting element D3 also allows the negative level shift. Nevertheless, reverse current in the load electromagnet 10 is avoided.

Other configurations are the same as those in the first embodiment.

As shown in FIG. 4A, first-stage current i ₁ rises and increases _first , and then subsequent-stage current i ₂ rises with a delay of a predetermined time difference T _S2 . The first stage current i ₁ gradually decreases as the subsequent stage current i ₂ gradually increases. As the subsequent stage current i ₂ increases and approaches its highest level, the first stage current i ₁ approaches its lowest level. When the first stage current i ₁ approaches the lowest level and reaches 0 level, the first stage current i ₁ can go to the negative level due to the presence of the antiparallel unidirectionally conducting element. That is, a part of the succeeding stage current i ₂ that has exited from the waveform adjusting coil L2 of the succeeding stage charging/discharging circuit 22 flows into the first stage capacitor C1 via the first one-way conducting element D2. As described above, in the second embodiment, the limit action having the lower limit of 0 level as in the conventional example shown in FIG. 6 does not work.

The current i _{2 in the} succeeding stage smoothly rises, reaches its highest level, and subsequently draws a smooth curve and starts to decrease. During this period, the first-stage current i ₁ drops smoothly, passes through the 0 level and enters the minus level, then continues to fall in a smooth curve, reaches its lowest level, and subsequently rises in a smooth curve. Turn to.

Subsequent stage current i ₂ also stage current i ₁ is also both its entirety, especially pole (highest level, the lowest level) is also in the vicinity, because changes smoothly continuously formed, the subsequent stage current i ₂ and stage current i ₁ The combined load electromagnet current i ₃ also changes smoothly and continuously.

FIG. 4 (b) is an enlarged view of the vicinity of the flat-top portion F of FIG. 4 (a), 9 of the conventional case shown in FIG. 6, as compared with FIG. 10, continuous in the load electromagnet current i ₃ It is possible to recognize the improvement of the property and symmetry, and the improvement of the flatness. Further, even when compared with FIG. 2 in the case of the first embodiment shown in FIG. 1, a significant improvement in flatness can be recognized.

In this way, the continuity of the first-stage current i _{1 at} the lowest level is restored, so that the flatness of the flat top portion F can be improved while bringing the load electromagnet current i ₃ close to a highly symmetrical waveform similar to a trapezoid. It is possible to make a great improvement.

Other operations are similar to those in the first embodiment.

[Modification]
The present invention is not limited to the above embodiment, but can be modified as follows. For example, in the second embodiment, the first unidirectional conducting element D2 and the second unidirectional conducting element D3 are used instead of the variable resistor VR1 in the first embodiment. Without being limited thereto, the first unidirectionally conducting element D2 and the second unidirectionally conducting element D3 may be used together with the variable resistor VR1 as shown in FIG. Thereby, the flatness of the flat top portion F can be further improved.

INDUSTRIAL APPLICABILITY The present invention is used for a charged particle beam accelerator and the like, and relates to a pulse power supply device having a pulse forming circuit network (PFN) of a plurality of stages, which shows a pulse current waveform caused by a change in circuit constant with temperature change. It is useful as a technique for optimizing the waveform of the generated pulse current by canceling the change in the peak value of the pulse current waveform at the flat top portion and the change in the inclination of the waveform main portion with respect to the fluctuation phenomenon. In particular, the waveform of the load electromagnet current eliminates discontinuities and recovers and transforms the entire waveform into a continuous waveform, bringing the load electromagnet current closer to a highly symmetric waveform similar to a trapezoid, while This is useful for further improving flatness.

10 load electromagnet 21 first stage charge/discharge circuit 22 subsequent stage charge/discharge circuit 30 trigger control circuit 31 trigger timing adjustment circuit 32 first stage gate drive circuit 33 first stage pulse transformer 34 subsequent stage gate drive circuit 35 subsequent stage pulse transformation 40 Charger capable of adjusting charging voltage setting value 51 Current waveform measuring device 52 Current waveform recording means 53 Current waveform calculating means 54 Charging voltage control circuit 55 Time difference control circuit C1 First stage capacitor C2 Subsequent stage capacitor D2 In antiparallel connection First unidirectional conducting element D3 Second unidirectional conducting element L2 Waveform adjusting coil S1 First stage unidirectional switch S2 Subsequent unidirectional switch VR1 Variable resistor

Claims (4)

A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A series circuit of a first-stage capacitor and a first-stage unidirectional switch, and a first-stage charging/discharging circuit capable of discharging the charging power of the first-stage capacitor to the circuit part of the load electromagnet,
A charging/discharging circuit of a succeeding stage, which comprises a series circuit of a capacitor of a succeeding stage, a one-way switch of the succeeding stage, and a waveform adjusting coil, and which can discharge the charging power of the capacitor of the succeeding stage to the circuit portion of the load electromagnet In addition to the above,
A charger that charges the first-stage capacitor and the subsequent-stage capacitor, and has a charge voltage setting value adjustable,
A pulse power supply device that sends trigger signals that are independent of each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and includes a trigger control circuit capable of adjusting the time difference between the trigger signals. And
A variable resistor is inserted in the charge/discharge circuit of the first stage, and a flat top portion of the trapezoidal waveform of the pulse current flowing in the circuit portion of the load electromagnet is discontinuous in that its differential coefficient changes from minus to plus. A pulse power supply device characterized in that the flatness of the flat top portion is improved by changing from a double chevron shape to a single continuous chevron shape and approaching a highly symmetrical waveform . A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A series circuit of a first-stage capacitor and a first-stage unidirectional switch, and a first-stage charging/discharging circuit capable of discharging the charging power of the first-stage capacitor to the circuit part of the load electromagnet,
A charging/discharging circuit of a succeeding stage, which comprises a series circuit of a capacitor of a succeeding stage, a one-way switch of the succeeding stage, and a waveform adjusting coil, and which can discharge the charging power of the capacitor of the succeeding stage to the circuit portion of the load electromagnet In addition to the above,
A charger that charges the first-stage capacitor and the subsequent-stage capacitor, and can adjust the charging voltage setting value,
A pulse power supply device which sends trigger signals independent of each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and a trigger control circuit capable of adjusting a time difference between the trigger signals. And
A one-way energizing element is connected in anti-parallel to the first-stage one-way switch in the first-stage charge/discharge circuit, and a flat top portion of the trapezoidal-like waveform of the pulse current flowing in the circuit portion of the load electromagnet, The characteristic is that the flatness in the flat top part is improved by changing from a discontinuous two-peak shape whose differential coefficient changes from negative to positive to a single continuous peak shape and approaching a highly symmetrical waveform. Pulse power supply. A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A series circuit of a first-stage capacitor and a first-stage one-way switch, and a first-stage charging/discharging circuit capable of discharging the charging power of the first-stage capacitor to the circuit portion of the load electromagnet,
A charging/discharging circuit of a succeeding stage, which comprises a series circuit of a capacitor of a succeeding stage, a one-way switch of the succeeding stage, and a waveform adjusting coil, and which can discharge the charging power of the capacitor of the succeeding stage to the circuit portion of the load electromagnet In addition to the above,
A charger that charges the first-stage capacitor and the subsequent-stage capacitor, and has a charge voltage setting value adjustable,
A pulse power supply device that sends trigger signals that are independent of each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and includes a trigger control circuit capable of adjusting the time difference between the trigger signals. And
A variable resistor is inserted in the first-stage charging/discharging circuit, and a one-way conducting element is connected in antiparallel to the first-stage one-way switch in the first-stage charging/discharging circuit , and a circuit part of the load electromagnet is connected. The flat top part of the trapezoidal waveform similar to the pulse current flowing in is changed from the discontinuous two peaks whose differential coefficient changes from negative to positive to one continuous peak and close to the highly symmetrical waveform. And a flatness of the flat top portion is improved . A unidirectional energization element is inserted between the connection point between the charge/discharge circuit of the first stage and the charge/discharge circuit of the subsequent stage and the load electromagnet in a direction from the connection point to the load electromagnet. The pulse power supply device according to claim 2 or claim 3.

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