JP2018050094A - Pulse power supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform recovery deformation to a continuous waveform as a whole by removing discontinuous part in a waveform of a load electromagnet current, and to improve flatness of a flat top of the load electromagnet current while making the load electromagnet current approach to a high symmetrical waveform similar to a trapezoidal shape.SOLUTION: A pulse power supply apparatus includes: a first-stage charge/discharge circuit 21 connecting both ends of a load electromagnet by a series circuit of a capacitor C1 and a one-way switch S1; one or more succeeding charge/discharge circuits 22 connecting both ends of the load electromagnet or a first-stage capacitor by a series circuit of a capacitor C2, a one-way switch S2 and a waveform adjusting coil L2; a charger 40 capable of adjusting charge voltage set values of respective capacitors; and a trigger control circuit 30 capable of adjusting a time difference between respective trigger signals by sending mutually independent trigger signals and closing the first-stage one-way switch and the succeeding one-way switches. Further, a variable resistor VR1 is inserted into the first-stage charge/discharge circuit 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply used in an accelerator for accelerating a charged particle beam in the form of a pulse, and relates to a pulse power supply apparatus including 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 vacuum vessel material and the like due to the radiation generated when the charged particle beam collides with the wall surface of the vacuum vessel becomes serious. 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 with 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 a configuration of a conventional pulse power supply device described in Patent Document 1. In FIG. 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 that is composed of a series circuit of a first stage capacitor C1 and a first stage one-way switch S1 and that can discharge the charging power of the first stage capacitor C1 to the circuit portion 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 can subsequently discharge the charging power of the succeeding stage capacitor C2 to the circuit portion of the load electromagnet 10. Stage charging and discharging circuit 22,
(3) A charger 40 for charging the first-stage capacitor C1 and the subsequent-stage capacitor C2 and capable of adjusting the charge voltage setting value;
(4) A trigger control circuit 30 which sends out trigger signals independent of each other and closes the one-way switch S1 at the first stage and the one-way switch S2 at the subsequent stage, and can adjust the time difference between the trigger signals.
It 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 subsequent stage charge / discharge circuit 22 is also connected between both ends of the load electromagnet 10. That is, the first stage charging / discharging circuit 21 and the subsequent stage charging / discharging circuit 22 are connected to the load electromagnet 10 in parallel. As the one-way switches S1 and S2, thyristors that automatically extinguish when the current direction is reversed are used.

The trigger control circuit 30 includes a trigger timing adjustment circuit 31, an initial stage gate drive circuit 32, an initial stage pulse transformer 33 for closing the initial stage one-way switch S1, a subsequent stage gate drive circuit 34, and a subsequent stage one. A subsequent stage pulse transformer 35 for closing the direction switch S2 is included. When the trigger timing adjustment circuit 31 receives the excitation trigger signal Str from the timing system in the charged particle beam apparatus, the time difference T _S2 (several microseconds to several tens of seconds) with respect to the first stage gate drive circuit 32 and the subsequent stage gate drive circuit 34. The trigger signals T1 and T2 are sent out in μsec). The trigger timing adjustment circuit 31 first outputs a trigger signal T1 to the first stage gate drive circuit 32, and outputs a trigger signal T2 to the subsequent stage gate drive circuit 34 with a predetermined time difference T _S2 .

  The positive terminal of the output voltage variable charger 40 is connected to the positive terminal of the first capacitor C1 via the first charging resistor R1, and the negative terminal of the capacitor C1 is connected to the negative terminal of the charger 40. Yes. Further, the positive terminal of the charger 40 is connected to the positive terminal of the capacitor C2 at the subsequent stage via the charging resistor R2 at the subsequent 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 and a pulse current waveform flowing in a load electromagnet of a conventional pulse power supply device.

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

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

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

  Hereinafter, the change of the waveform in the flat top part F (refer FIG. 7) of the pulse current which flows into the load electromagnet 10 is demonstrated.

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 decrease in the peak value of the load electromagnet current i ₁₃ is compensated by increasing the charge voltage setting command signal given to the charger 40. However, there is a problem that the inclination in 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. As the temperature changes, the resistance value of the resistance component 12 in the load electromagnet 10 (including the resistance value of the power feeding cable) fluctuates, causing a change in the current waveform at the flat top portion F.

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

For example, as shown in FIG. 7, the resistance value of the circuit of the load electromagnet 10 is changed from 20 mΩ to 20.9 mΩ and 21.8 mΩ, showing changes in the voltage / current waveform of each part of the pulse power supply device and the pulse current waveform flowing in the load electromagnet 10. As the time increases, the time difference T _S2 (indicated as “TS2” in FIG. 7C) for igniting the one-way switch S2 of the subsequent stage is gradually increased from 0 μs to 2 μs and 4 μs, and 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% with respect 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 increases as the temperature rises. The flatness of the current in the part F can be improved.

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

  In the conventional way of thinking, the charging voltage for the capacitors C1 and C2 is merely variable. In this case, it has been considered that it is possible to suppress a change in the peak value of the pulse current waveform (the peak value decreases due to temperature rise).

  However, since the charging voltage is simply adjusted, it is not possible to compensate for the change in the flatness of the current in the flat top portion F. That is, as the temperature rises, the resistance value increases, the inclination in the direction in which the current falls increases, and the flatness of the current in the flat top portion F deteriorates.

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

Japanese Unexamined Patent Publication No. 2016-1000068

However, in the conventional example shown in FIG. 6, in practice, the overall effect of the capacitance of the initial stage capacitor C1, the subsequent stage capacitor C2, the waveform adjusting coil L2, and the resistance and inductance components of the wiring ( As shown in FIG. 8, the current (initial stage current) i ₁₁ flowing through the first stage charging / discharging circuit 21 and the current (subsequent stage current) i ₁₂ flowing through the subsequent stage charging / discharging circuit 22 are shown in FIG. Each waveform is easily disturbed, and a new problem has arisen in that the waveform symmetry and flatness of the current (synthetic current) i ₁₃ (= i ₁₁ + i ₁₂ ) flowing through the circuit portion of the load electromagnet 10 are adversely affected.

That is, as shown in FIG. 8, distortion occurs in the initial stage current i ₁₁ and the subsequent stage current i ₁₂ compared to the waveform of FIG. The waveform of the load electromagnet current i ₁₃ rises more rapidly in the first half and later in the second half, and the symmetry is greatly impaired. In other words, the flatness is greatly reduced because the waveform is greatly deformed from an ideal high symmetry waveform similar to a trapezoidal shape.

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

The peak value of the load electromagnet current i ₁₃ is 21215 [A], and the timing indicating the peak value is 262.159 [μs]. The drop current value from the peak value to the current value corresponding to the 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]
It becomes. The flatness is preferably as the value is smaller. In recent years, in a pulse power supply for a state-of-the-art high-energy charged particle accelerator exceeding 1 billion electron volts, 212 [ppm] is too large. There is a strong demand to reduce the size, that is, to further improve the flatness (less than half).

As a countermeasure against this flatness improvement, in the conventional example shown in FIG. 6, by adjusting the subsequent stage current i time difference T _S2 is the delay time of the rising timing of ₁₂ from rising timing of the first-stage current i _11, in FIG. 7 When the length was made much longer than the cases (2 [μs] and 4 [μs]), for example, 60 [μs], the result shown in FIG. 9 was obtained. FIG. 10 clearly shows the difference between FIG. 9 and FIG.

8A, 9A, and 10A, the horizontal axis and the vertical axis are the same. 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. The waveform relating to FIG. 8A is indicated by a thin line, and the waveform relating to FIG. 9A is indicated by a thick line.

In FIG. 10 (a), the rising timing of the single-crested succeeding stage current i12 _{(FIG. 8)} indicated by the thin dotted thin lines is 0 [μs], whereas the interval The rise time of the subsequent current i _{12 (FIG. 9)} having a single peak shape indicated by a thick thick dotted line is delayed and the delay time is 60 [μs]. In addition, the mountain-shaped first-stage current i _{11 (FIG. 8)} indicated by a thin dotted thin line shows a minimum value in the vicinity of 370 [μs], but the change in the differential coefficient around that is continuous. It has become. That is, the waveform change is smooth. On the other hand, a mountain-shaped first-stage current i _{11 (FIG. 9)} indicated by a thick dotted line with a wide interval becomes 0 level in the vicinity of 300 [μs], and is 0 from about 300 [μs] to about 370 [μs]. The level continues, and gradually rises from the 0 level around 370 [μs]. That is, the first stage current i _{11 (FIG. 9)} has a discontinuous differential coefficient and loses smoothness in waveform change.

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

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

The load electromagnet current i _{13 (Fig. 8)} is thicker than the thin electromagnet current i _{13 (Fig. 8)} due to the synergy of the subduction on the first half and the bulge on the rear half _{. 9)} presents a shape closer to a highly symmetrical waveform similar to a trapezoidal shape.

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

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

FIG. 10B is a graph with the same scale on both the vertical axis and the vertical axis in FIG. 9B. The load electromagnet current i _{13 (FIG. 9)} in FIG. 9B and the load electromagnet current in FIG. i _{13 (FIG. 8)} . The current axis, which is the vertical axis, is a relative scale. This is intended to represent a shape change for 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 apparent from FIGS. 8, 9, and 10, when the subsequent stage current i ₁₂ is delayed by 60 [μs] with respect to the first stage current i ₁₁ and is started up, the first stage current i ₁₁ as shown in FIG. 9A. Becomes a discontinuous state in which the zero level continues for a certain time, and accordingly, 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). On the other hand, it becomes closer to the highly symmetrical waveform, but as shown in the comparison between FIG. 8B and FIG. 9B, or as shown in FIG. It exhibits a two-sided waveform, and the flatness is extremely deteriorated.

Note that the load electromagnet current i _{13 (FIG. 8)} in _{FIG. 10B} is a waveform, and the thick solid line portion of the load electromagnet in the range of about 256 to 268 [μs] illustrated in FIG. 8B. This corresponds to the current i ₁₃ . A thin broken line portion shows that it is one mountain shape even if the range is expanded.

When the subsequent stage current i ₁₂ is delayed and started up, the load electromagnet current i _{13 (FIG. 9) shown in FIG. 10B} has a discontinuous two-peaked waveform in which the differential coefficient changes from negative to positive at once. Thus, it deviates from the required range of instantaneous current values, and this makes it impossible to accurately maintain the trajectory of the charged particle beam.

  The present invention has been created in view of such circumstances, and with respect to a pulse power supply device, the load electromagnet current is restored and deformed into a continuous waveform by eliminating the discontinuous portion in the waveform of the load electromagnet current. The object is to further improve the flatness of the flat top portion while bringing the current close to a highly symmetric waveform similar to a trapezoidal shape.

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

<1> A first pulse power supply device according to the present invention includes:
A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A first stage charge and discharge circuit that is composed of a series circuit of a first stage capacitor and a first direction one-way switch, and that can discharge the charge power of the first stage capacitor to the circuit portion of the load electromagnet,
A succeeding stage charge / discharge circuit comprising a series circuit of a succeeding stage capacitor, a succeeding stage one-way switch, and a waveform adjusting coil, and capable of discharging the charging power of the succeeding stage capacitor to the circuit portion of the load electromagnet. With the above,
Charge the first stage capacitor and the subsequent stage capacitor, a charger capable of adjusting the charging voltage setting value,
A pulse power supply device comprising: a trigger control circuit capable of sending trigger signals independent from each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and capable of adjusting a time difference between the trigger signals. Because
A variable resistor is inserted in the first stage charge / discharge circuit.

<2> A second pulse power supply device according to the present invention includes:
A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A first stage charge and discharge circuit that is composed of a series circuit of a first stage capacitor and a first direction one-way switch, and that can discharge the charge power of the first stage capacitor to the circuit portion of the load electromagnet,
A succeeding stage charge / discharge circuit comprising a series circuit of a succeeding stage capacitor, a succeeding stage one-way switch, and a waveform adjusting coil, and capable of discharging the charging power of the succeeding stage capacitor to the circuit portion of the load electromagnet. With the above,
Charge the first stage capacitor and the subsequent stage capacitor, a charger capable of adjusting the charging voltage setting value,
A pulse power supply device comprising: a trigger control circuit capable of sending trigger signals independent from each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and capable of adjusting a time difference between the trigger signals. Because
A one-way energization element is connected in reverse parallel to the first-stage switch in the first-stage charge / discharge circuit.

<3> A third pulse power supply device according to the present invention provides:
A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A first stage charge and discharge circuit that is composed of a series circuit of a first stage capacitor and a first direction one-way switch, and that can discharge the charge power of the first stage capacitor to the circuit portion of the load electromagnet,
A succeeding stage charge / discharge circuit comprising a series circuit of a succeeding stage capacitor, a succeeding stage one-way switch, and a waveform adjusting coil, and capable of discharging the charging power of the succeeding stage capacitor to the circuit portion of the load electromagnet. With the above,
Charge the first stage capacitor and the subsequent stage capacitor, a charger capable of adjusting the charging voltage setting value,
A pulse power supply device comprising: a trigger control circuit capable of sending trigger signals independent from each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and capable of adjusting a time difference between the trigger signals. Because
A variable resistor is inserted into the first stage charge / discharge circuit, and a one-way energization element is connected in reverse parallel to the first stage one-way switch in the first stage charge / discharge circuit.

  <1A> In the pulse power supply device configured as described in <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 charge / discharge circuit. The flat part recognized in the lower level part is eliminated, and the entire waveform is adjusted to change smoothly. That is, the entire waveform is recovered and deformed so as to eliminate the discontinuous portion of the waveform. As a result, it is possible to improve the flatness of the flat top portion while bringing the load electromagnet current formed by the combination of the initial stage current and the delayed subsequent stage current close to a highly symmetrical waveform similar to a trapezoidal shape.

  <2A> In the pulse power supply device having the above configuration <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 once increased falls and approaches its lowest level, the first-stage current can proceed to the negative level due to the presence of the antiparallel unidirectional energization element. That is, the limit action with the 0 level as the lower limit as in the conventional example does not work. Since the continuity at the lowest level of the first stage current is restored in this way, the load electromagnet current composed of the combination of the first stage current and the delayed subsequent stage current is brought close to a highly symmetrical waveform similar to a trapezoidal shape. It becomes possible to greatly improve the flatness in the flat top portion.

  <3A> In the pulse power supply device configured as described in <3> above, a variable resistor is inserted into the first-stage charging / discharging circuit, and a one-way energization element is connected in antiparallel to the first-stage one-way switch. . Thereby, the improvement of the flatness in a flat top part can be aimed at further.

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

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

  According to the present invention, the load electromagnet current is made highly symmetrical similar to a trapezoid by increasing the adjustment elements for eliminating the discontinuous portion in the waveform of the load electromagnet current and restoring the entire waveform to a continuous one. The flatness at the flat top can be improved while being sufficiently close to the waveform.

1 is a circuit diagram showing a configuration of a pulse power supply device according to a first embodiment of the present invention. The wave form diagram which shows the pulse current waveform which flows into each charging / discharging circuit and load electromagnet of the first stage of the pulse power supply device in 1st Example of this invention, and a subsequent stage The circuit diagram which shows the structure of the pulse power supply device in 2nd Example of this invention The wave form diagram which shows the pulse current waveform which flows into each charging / discharging circuit and load electromagnet of the first stage and subsequent stage of the pulse power supply device in 2nd Example of this invention The circuit diagram which shows the structure of the pulse power supply device in the modification of this invention Circuit diagram showing configuration of pulse power supply device in conventional example Waveform diagram showing the voltage / current waveform of each part of the pulse power supply device and the pulse current waveform flowing in the load electromagnet Waveform diagram to point out problems of conventional pulse power supply device Waveform diagram to point out problems of conventional pulse power supply device Waveform diagram to point out problems of conventional pulse power supply device

  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 specific examples.

[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 waveform of a pulse current flowing in charge / discharge circuits and load electromagnets in the first and subsequent stages of the pulse power supply device. FIG.

  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 capacitor C1 and the first stage in the first stage. A first-stage charge / discharge circuit in which a one-way switch S1 and a variable resistor VR1 are connected in series and connected between both ends of a load electromagnet 10 (a series circuit of an inductance component 11 and a resistance component 12). This is a subsequent stage charge / discharge circuit in which C2, a subsequent stage one-way switch S2 and a waveform adjusting coil L2 are connected in series and connected between both ends of the load electromagnet 10. The variable resistor VR1 has a very small resistance value of several mΩ to several tens of mΩ, and is composed of, for example, a copper bar or a cable, and the resistance value is adjusted. In the case of the present embodiment, the number of stages of the charge / discharge 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 may be replaced with another control switching element.

  In the first stage charge / discharge circuit 21, the anode terminal (anode) of the first stage one-way switch S1 composed of a thyristor is connected to the positive terminal of the first stage capacitor C1 whose negative terminal is connected to the load electromagnet 10. The one-way switch A variable resistor VR1 is connected to the cathode terminal (cathode) of S1. In the subsequent stage charging / discharging circuit 22, the anode terminal (anode) of the subsequent one-way switch S <b> 2 including a thyristor is connected to the positive terminal of the subsequent capacitor C <b> 2 connected to the load electromagnet 10. 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 adjusting coil L2 are connected to each other, and the connection point is connected to the load electromagnet 10.

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, 34 is a subsequent stage gate drive circuit, Reference numeral 35 denotes a subsequent stage pulse transformer for closing the one-way switch S2 of the subsequent 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 (several to the gate drive circuit 32 in the first stage and the gate drive circuit 34 in the subsequent stage is measured. The trigger signals T1 and T2 are transmitted in a period of [mu] seconds to several tens of [mu] seconds).

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

  In FIG. 1, 40 is a charger (variable output voltage type) whose output voltage is adjustable, D1 is a protection diode, and R1 and R2 are charging resistors. The protection diode D1 is connected between both ends of the charger 40. The positive terminal of the 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. Further, the positive terminal of the charger 40 is connected to the positive terminal of the capacitor C2 at the subsequent stage via the charging resistor R2 at the subsequent 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 first stage charge / discharge circuit 21 in comparison with the conventional example shown in FIG. Note that the insertion point of the variable resistor VR1 in the first stage charging / discharging circuit 21 is not between the waveform adjusting coil L2 and the first stage one-way switch S1, but the first stage capacitor C1 and the first stage one-way switch S1. It may be between.

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

  The first stage capacitor C1 is charged from the charger 40 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 apparatus is input to the trigger timing adjustment circuit 31, the trigger timing adjustment circuit 31 includes the first stage gate drive circuit 32 and the subsequent stage gate. Trigger signals T1, T2 are sequentially sent to the drive circuit 34 with a predetermined time difference T _S2 .

The first stage gate drive circuit 32 to which the trigger signal T1 is input outputs a gate pulse to the first stage one-way switch S1 via the first stage pulse transformer 33, and turns on the first stage one-way switch S1. Further, after a predetermined time difference T _S2 , the succeeding stage gate drive circuit 34 to which the trigger signal T 2 is input outputs a gate pulse to the succeeding stage one-way switch S 2 via the succeeding stage pulse transformer 35, and the succeeding stage The one-way switch S2 is turned on. The predetermined time difference T _S2 is opened between the turn-on timing of the first one-way switch S1 and the turn-on timing of the subsequent one-way switch S2.

The output timing of the excitation trigger signal Str for the trigger timing adjustment circuit 31 is determined as follows. In the charged particle beam apparatus, the pulse current flowing through the load electromagnet 10 reaches a peak value at the timing when the charged particle beam to which the magnetic field is applied 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 a period during which the charged particle beam passes through the load electromagnet 10.

  Hereinafter, changes in the current waveform in the flat top portion F will be described.

  The resistance value of the resistance component 12 in the circuit portion of the load electromagnet 10 varies with a change in temperature, resulting in a change in the current waveform in the flat top portion F. The resistance value of the resistance component 12 includes a resistance value of a cable for supplying power to the load electromagnet 10 from the pulse power supply device. As the power supply cable, a coaxial cable is normally 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. In particular, in an accelerator application that accelerates a charged particle beam in a pulsed manner intermittently, the conductor temperature may increase by several tens of degrees Celsius due to Joule heat due to 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, the peak of the load electromagnet current i ₃ is increased by increasing the charge voltage setting command signal given to the charger 40 as described in the conventional example. There is the idea of compensating for the drop in value. However, there is a problem 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, in the trigger timing adjustment circuit 31, an adjustable time difference T _S2 is provided for the two trigger signals T1, T2 for closing the one-way switch S1 of the first stage and the one-way switch S2 of the subsequent stage, 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 so as to increase as the temperature rises, an attempt is made to improve the flatness of the current in the flat top portion F. It is done.

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, and the resistance component and inductance component of the waveform adjustment coil L2 and wiring Even if the time difference T _S2 between the rising timings of the two trigger signals T1 and T2 is variously adjusted due to the influence of mutual interference, the flatness of the current in the flat top portion F can be easily improved. There wasn't.

In other words, the waveform of the load electromagnet current i ₃ can be brought close to an ideal trapezoidal similar waveform (improving the symmetry between the first half and the second half), but it is strictly in the flat top portion F. When observing a simple 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 double mountain shape in the differential coefficient. An inconvenient situation was incurred (see FIGS. 8, 9 and 10).

On the other hand, in the first embodiment of the present invention, the variable resistor VR1 is inserted into the first stage charge / discharge circuit 21, and the differential coefficient in the waveform of the first stage current i ₁ causing the above inconvenience is obtained. Discontinuity (continuation of 0 level for a certain period of time) can be eliminated, and the waveform can be made 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 Improvement in symmetry and symmetry, and improvement in flatness can be observed.

That is,
(1) A configuration in which the charger 40 that charges the first-stage capacitor C1 and the subsequent-stage capacitor C2 is made variable so that the charging voltage set value can be adjusted;
(2) A trigger control circuit 30 having a rise timing time difference T _S2 between the two trigger signals T1, T2 for the first-stage one-way switch S1 and the subsequent-stage one-way switch S2, and making the time difference T _S2 adjustable. Configuration,
(3) With the above three configurations in which the variable resistor VR1 is inserted into the first stage charge / discharge circuit 21, the degree of freedom of waveform adjustment of the load electromagnet current i ₃ is increased.

As a result, the waveform of the load electromagnet current i ₃ is close to an ideal high symmetry waveform similar to a trapezoid (improving the symmetry between the first half and the second half), and at the flat top F The waveform of the first stage current i ₁ and thus the differential coefficient of the waveform of the load electromagnet current i ₃ are made strictly continuous (dissolving the two discontinuous peaks in the case of the conventional example), and the waveform of the load electromagnet current i ₃ is smoothed. It became possible to be a thing.

[Second Embodiment]
FIG. 3 is a circuit diagram showing the configuration of the pulse power supply apparatus according to the second embodiment of the present invention, and FIG. 4 is a waveform showing the waveform of the pulse current flowing through each charge / discharge circuit and load electromagnet of the first stage and the subsequent stage of the pulse power supply apparatus. FIG. 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 has a first one-way energization in reverse parallel 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 one-way energization element D2. The first one-way energization element D2 is connected in reverse parallel to the first-stage one-way 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 that it has been.

  A second one-way energization element D3 is inserted between the connection point between the first-stage one-way switch S1 and the waveform adjustment coil L2 and the input terminal of the load electromagnet 10. A diode is also used as the second one-way energization element D3.

The first unidirectional energization element D2 and the second unidirectional energization element D3 have the following relationship. In the case of the first embodiment, it is not assumed that the subsequent stage current i ₂ output from the subsequent stage charging / discharging circuit 22 flows into the first stage charging / discharging circuit 21. This is reflected in FIG. 9A and FIG. 10A that the lowest level of the first-stage current i ₁ that falls is 0 level.

On the other hand, in the second embodiment, a subsequent stage current i output from the subsequent stage charge / discharge circuit 22 is obtained by reversely connecting the first one-way energization element D2 to the first stage one-way switch S1. ₂ is going to flow into the charge / discharge circuit 21 of the first stage. That is, it is for reverse charging the first stage capacitor C1. As a result, the first-stage capacitor C1 is allowed to be charged / discharged with the high side terminal on the low potential side and the low side terminal on the high potential side. That is, it is possible to allow the first stage current i ₁ to become a negative level.

  The reason for inserting the second one-way energization 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 current from flowing in the opposite direction to the electromagnet 10.

That is, in this embodiment, the addition of the first one-way energization element D2 allows the first-stage current i ₁ to shift to the minus level, but the addition of the second one-way energization element D3 allows the negative level shift. Regardless, the 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, the first stage current i ₁ rises and increases _first , and then the subsequent stage current i ₂ rises with a delay of a predetermined time difference T _S2 . As the subsequent stage current i ₂ gradually increases, the initial stage current i ₁ gradually decreases. 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 its lowest level and reaches the 0 level, the first stage current i ₁ can proceed to the negative level due to the presence of the antiparallel unidirectional energization element. That is, a part of the subsequent stage current i ₂ that has exited the waveform adjustment coil L2 of the subsequent stage charge / discharge circuit 22 flows into the first stage capacitor C1 via the first one-way energization element D2. Thus, in the second embodiment, the limit action with the 0 level as the lower limit as in the conventional example shown in FIG. 6 does not work.

The succeeding stage current i ₂ rises smoothly and reaches its highest level, and then continues to draw a smooth curve and starts to decrease. During this time, the first-stage current i ₁ drops smoothly, passes through the zero level and enters the minus level, continues to fall in a smooth curve, reaches its lowest level, and then 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 synthesized 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 Improvement in symmetry and symmetry, and improvement in flatness can be observed. 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, since the continuity at the lowest level of the _first stage current i ₁ is restored, the flatness at the flat top portion F is increased while bringing the load electromagnet current i ₃ close to a highly symmetrical waveform similar to a trapezoidal shape. It is possible to greatly improve.

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

[Modification]
The present invention is not limited to the above-described embodiment, and can be modified as follows. For example, in the second embodiment, instead of the variable resistor VR1 in the first embodiment, the first unidirectional energization element D2 and the second unidirectional energization element D3 are used. Without being limited thereto, as shown in FIG. 5, the first unidirectional energization element D2 and the second unidirectional energization element D3 may be used together with the variable resistor VR1. Thereby, the flatness in the flat top part F can be further improved.

  The present invention is used for a charged particle beam accelerator or the like, and relates to a pulse power supply device including a plurality of stages of a pulse forming network (PFN), and a pulse current waveform caused by a change in a circuit constant accompanying a temperature change. It is useful as a technique for optimizing the waveform of the pulse current to be generated by canceling the change in the peak value of the pulse current waveform at the flat top part and the inclination of the waveform main part against the fluctuation phenomenon. In particular, the waveform of the load electromagnet current is restored and deformed to eliminate the discontinuity and the entire waveform is continuous. Useful for further flatness improvement.

DESCRIPTION OF SYMBOLS 10 Load electromagnet 21 First stage charging / discharging circuit 22 Subsequent stage charging / discharging 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 with adjustable charging voltage set 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 Reverse parallel connection First unidirectional energization element D3 Second unidirectional energization element L2 Waveform adjustment coil S1 First stage unidirectional switch S2 Subsequent stage 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 first stage charge and discharge circuit that is composed of a series circuit of a first stage capacitor and a first direction one-way switch, and that can discharge the charge power of the first stage capacitor to the circuit portion of the load electromagnet,
A succeeding stage charge / discharge circuit comprising a series circuit of a succeeding stage capacitor, a succeeding stage one-way switch, and a waveform adjusting coil, and capable of discharging the charging power of the succeeding stage capacitor to the circuit portion of the load electromagnet. With the above,
Charge the first stage capacitor and the subsequent stage capacitor, a charger capable of adjusting the charging voltage setting value,
A pulse power supply device comprising: a trigger control circuit capable of sending trigger signals independent from each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and capable of adjusting a time difference between the trigger signals. Because
A pulse power supply device, wherein a variable resistor is inserted in the first stage charge / discharge circuit. A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A first stage charge and discharge circuit that is composed of a series circuit of a first stage capacitor and a first direction one-way switch, and that can discharge the charge power of the first stage capacitor to the circuit portion of the load electromagnet,
A succeeding stage charge / discharge circuit comprising a series circuit of a succeeding stage capacitor, a succeeding stage one-way switch, and a waveform adjusting coil, and capable of discharging the charging power of the succeeding stage capacitor to the circuit portion of the load electromagnet. With the above,
Charge the first stage capacitor and the subsequent stage capacitor, a charger capable of adjusting the charging voltage setting value,
A pulse power supply device comprising: a trigger control circuit capable of sending trigger signals independent from each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and capable of adjusting a time difference between the trigger signals. Because
A pulse power supply device, wherein a one-way energization element is connected in antiparallel to the first-stage one-way switch in the first-stage charge / discharge circuit. A pulse power supply device for supplying a pulse current having a trapezoidal waveform to a circuit portion of a load electromagnet,
A first stage charge and discharge circuit that is composed of a series circuit of a first stage capacitor and a first direction one-way switch, and that can discharge the charge power of the first stage capacitor to the circuit portion of the load electromagnet,
A succeeding stage charge / discharge circuit comprising a series circuit of a succeeding stage capacitor, a succeeding stage one-way switch, and a waveform adjusting coil, and capable of discharging the charging power of the succeeding stage capacitor to the circuit portion of the load electromagnet. With the above,
Charge the first stage capacitor and the subsequent stage capacitor, a charger capable of adjusting the charging voltage setting value,
A pulse power supply device comprising: a trigger control circuit capable of sending trigger signals independent from each other to close the one-way switch of the first stage and the one-way switch of the subsequent stage, and capable of adjusting a time difference between the trigger signals. Because
A variable resistor is inserted into the first stage charge / discharge circuit, and a one-way energization element is connected in reverse parallel to the first stage one-way switch in the first stage charge / discharge circuit. Power supply.   A unidirectional energization element in a direction from the connection point to the load electromagnet is inserted between a connection point between the first stage charge / discharge circuit and the subsequent stage charge / discharge circuit and the load electromagnet. The pulse power supply device according to claim 2 or claim 3.

Images