JP6324880B2 - Pulse power supply - Google Patents

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.

  As a waveform operation technique in a conventional power supply device using PFN, there is a method of manually or electrically operating a position-controllable short-circuit conductor provided close to a waveform adjustment coil of a component of PFN (for example, Patent Documents). 1). However, in this case, there is a problem that the mechanical structure is complicated and periodic maintenance such as lubrication is troublesome.

  On the other hand, in the method of controlling the applied voltage waveform in an analog manner, when manipulating the trajectory of a charged particle beam with high energy, it is necessary to serialize and parallel the output circuit in order to increase the voltage / current of the analog control circuit. (See, for example, Patent Documents 2 and 3). However, in this case, there is a problem that the apparatus becomes larger and complicated, resulting in higher costs and lower reliability.

FIG. 4 is a circuit diagram showing a configuration of a pulse power supply device using a conventional two-stage PFN circuit. 60 is a load electromagnet, 61 is an inductance component, 62 is a resistance component, 71 is a gate drive circuit, 72 is a pulse transformer (pulse transformer), 80 is a variable output voltage charger, R11 is a charging resistor, and C11 is A first capacitor, C12 is a second capacitor, L12 is a waveform adjustment coil, S11 is a switch such as a thyristor, and _Scv is a charge voltage setting command signal given to the output voltage variable charger 80. From the state where the first capacitor C11 and the second capacitor C12 are charged from the charger 80 via the charging resistor R11, the switch S11 is turned on. The switch S11 is turned on by starting the gate driving circuit 71, applying a gate pulse to the pulse transformer 72, and sending a trigger pulse to the switch S11. When the switch S11 is turned on, the charges stored in the first capacitor C11 and the second capacitor C12 flow to the circuit portion of the load electromagnet 60. At this time, the voltage is supplied from the second capacitor C12 via the waveform adjustment coil L12.

FIG. 5 shows a voltage / current waveform of each part of a conventional pulse power supply device and a pulse current waveform flowing through a load electromagnet. FIG. 5A shows waveforms of the voltage V11 of the first capacitor C11 and the voltage V12 of the second capacitor C12. FIG. 5B shows waveforms of the current i ₁₁ from the first capacitor C ₁₁ , the current i ₁₂ from the second capacitor C _12, and the current i ₁₃ (= i ₁₁ + i ₁₂ ) flowing through the circuit portion of the load electromagnet 60. . A current i ₁₃ obtained by combining the current i ₁₁ and the current i ₁₂ has a waveform similar to a trapezoid (a trapezoidal similar waveform). That is, the current i ₁₃ starts to rise with a slope corresponding to a value obtained by dividing the voltage V11 by the value of the inductance component 61 of the load coil from the turn-on timing (t = 0 ms) of the switch S11, and decreases with time. Then, it rises and eventually becomes a flat part (F) called a flat top part, and then descends with increasing negative slope over time.

FIG.5 (c) shows the waveform which expanded the flat top part F enclosed with the rectangular frame in FIG.5 (b). In FIG. 5C, the time axis is a region from t = 0.280 [ms] (= 280 [μs]) to t = 0.310 [ms] (= 310 [μs]), and the vertical axis is With the instantaneous current 3000 [A] as a reference value, the increase / decrease from this value is enlarged and displayed in the range of +5 [A] to −20 [A]. Three current waveforms A, B, and C are shown using the resistance value Rm of the resistance component 62 in the load electromagnet 60 as a parameter. This resistance value Rm includes the resistance value of the cable for supplying power to the load electromagnet 60. A coaxial cable is usually used as a power supply cable for pulsed high-power transmission, but it is difficult to use a water-cooled conductor as a constant temperature countermeasure for the cable due to insulation and cost problems. Particularly in the use of an accelerator that accelerates a charged particle beam in a pulsed manner intermittently, the circuit constant changes with the temperature change of each part of the load electromagnet or the pulse power supply device itself, thereby causing the current waveform to fluctuate. For example, the conductor temperature may increase by several tens of degrees Celsius due to Joule heat due to effective current, and as a result, the resistance value Rm of the load electromagnet 60 increases by about 10%, and the peak value of the load electromagnet current i ₃ decreases. (See FIG. 5 (c) A → B → C).

A current waveform A shown in FIG. 5C represents a waveform of the load electromagnet current i _{3 in} the reference state (resistance value Rm = 20.0 [mΩ], charging voltage Vc = 969.00 [V]).

A current waveform B shown in FIG. 5C represents the waveform of the load electromagnet current i ₃ when the temperature rises and the resistance value Rm increases and Rm = 20.9 [mΩ]. The current waveform B is -7.5 [A] (approximately 0.25%) lower than the current waveform A in the reference state of FIG.

A current waveform C shown in FIG. 5C represents the waveform of the load electromagnet current i ₃ when the temperature rises further and the resistance value Rm increases and Rm = 21.8 [mΩ]. This current waveform C is −15.5 [A] (approximately 0.52%) lower than the current waveform A in the reference state of FIG.

As a measure for compensating for the decrease in the peak value of the load electromagnet current i ₃ , there is a method of increasing the charging voltage in the charger 80. FIG. 6 shows an operation example when such measures are taken. FIG. 6C corresponds to FIG. 5C, and shows three current waveforms A, B ′, and C ′ using the charging voltage as a parameter. The current waveform in FIG. 6C is expressed by enlarging the amplitude (vertical axis direction) scale of the waveform in FIG. 5C by 25 times (with a smaller unit scale).

In FIG. 6C, B ′ indicates that the resistance value Rm is increased by the temperature rise from the reference state corresponding to the current waveform A (resistance value Rm = 20.0 [mΩ], charging voltage Vc = 969.00 [V]). When the value of Rm = 20.9 [mΩ] increases, the peak value of the load electromagnet current i ₃ decreases by approximately 0.25% as described above (see FIG. 5C). Compensation is performed by increasing the charging voltage Vc to Vc = 971.55 [V].

In FIG. 6C, C ′ is a resistance value due to a temperature rise from the reference state (resistance value Rm = 20.0 [mΩ], charging voltage Vc = 969.00 [V]) corresponding to the current waveform A. When Rm increases to Rm = 21.8 [mΩ], the peak value of the load electromagnet current i ₃ decreases by approximately 0.52% as described above (see FIG. 5C). The charging voltage Vc at 80 is compensated by increasing to Vc = 974.10 [V].

JP-A-8-125499 JP-A-9-92531 Japanese Patent Laid-Open No. 11-205098

  In the conventional pulse power supply device described above, the peak value can be compensated by adjusting the charging voltage Vc in the charger 80 as described above. However, since the charging voltage Vc 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, if you carefully observe FIG. 6C, the resistance value increases as the temperature rises, and as the current waveform changes from A → B ′ → C ′, the slope in the direction in which the current falls increases. There is a problem that the flatness of the current in the flat top portion F is deteriorated.

  A typical charged particle beam passage time width is approximately 10 [μs], and in FIG. 6C, the current flatness in the range from t = 290 [μs] to t = 300 [μs] is shown. It becomes a problem. When the deterioration of the flatness is evaluated by the change width of the instantaneous current value within this time range, the current waveform A in FIG. 6C is 0.12 [A] (approximately 0. 0 with respect to the peak value 3000 [A]. 004%) and 0.26 [A] for current waveform C (approximately 0.009% based on peak value 3000 [A]), and in particular for current waveform C, the accuracy of the instantaneous current value required for typical applications Even if the margin is small with respect to 0.01% and the error in charge voltage control is 0.005%, the current flatness of the current is poor, so that it deviates from the required range of instantaneous current values. It was happening.

  The present invention was created in view of such circumstances, and with respect to the pulse power supply device, with respect to the fluctuation phenomenon of the pulse current waveform caused by the change of the circuit constant accompanying the temperature change, with a relatively simple configuration, The object is to optimize the pulse current waveform similar to the trapezoidal shape by sufficiently suppressing the fluctuation of the current waveform.

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

The 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 first stage charge and discharge circuit comprising a series circuit of a first stage capacitor and a first stage switch, capable of discharging the charging power of the first stage capacitor to the circuit portion of the load electromagnet,
It comprises a series circuit of a succeeding stage capacitor, a succeeding stage switch, and a waveform adjusting coil, and includes at least one following stage charging / discharging circuit capable of discharging the charging power of the succeeding stage capacitor to the circuit portion of the load electromagnet. With
Charge the first stage capacitor and the subsequent stage capacitor, a charger capable of adjusting the charging voltage setting value,
Sending trigger signals independent of each other to close the first-stage switch and the subsequent-stage switch. By adjusting the time difference between the trigger signals , the pulse current waveform flowing in the circuit portion of the load electromagnet A trigger control circuit capable of improving the flatness of the flat top portion is provided.

  The feature of the present invention is that not only the adjustment of the capacitor charging voltage of each charging / discharging circuit but also the time difference adjustment of the trigger timing of the switch of each charging / discharging circuit is performed together. That is, by using a charging voltage variable type charger as a charger, each charging / discharging circuit is used for fluctuations in the pulse current waveform caused by changes in circuit constants accompanying temperature changes in each part of the load electromagnet and the pulse power supply device itself. By adjusting the charging voltage for the capacitor, the fluctuation of the current value (crest value) flowing in the circuit part of the load electromagnet is suppressed, and at the same time, the time difference of trigger timing for each charge / discharge circuit switch is adjusted in the trigger control circuit By doing this, the fluctuation of the peak value at the flat top portion of the pulse current waveform and the inclination of the main portion of the waveform is suppressed. By the above synergy, it is possible to optimize the pulse current waveform while sufficiently suppressing the fluctuation of the waveform.

  According to the present invention, for the pulse power supply device, with respect to the fluctuation phenomenon of the pulse current waveform caused by the change of the circuit constant accompanying the temperature change, by adjusting the charging voltage of each capacitor and adjusting the trigger timing of each switch, It is possible to optimize the waveform of the pulse current to be generated by canceling the change in the peak value at the flat top portion of the pulse current waveform and the inclination of the waveform main portion.

1 is a circuit diagram showing a configuration of a pulse power supply device according to a first embodiment of the present invention. FIG. 2 is a waveform diagram showing voltage / current waveforms of each part of the pulse power supply device and a pulse current waveform flowing in the load electromagnet in the first embodiment of the present invention; The circuit diagram which shows the structure of the pulse power supply device in 2nd Example 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 conventional pulse power supply device and the pulse current waveform flowing in the load electromagnet Waveform diagram to point out problems in the conventional pulse power supply

  The pulse power supply device of the present invention having the above configuration has several preferred modes as follows.

  The first stage charge / discharge circuit is connected between both ends of the load electromagnet circuit section, and the subsequent stage charge / discharge circuit is both ends of the load electromagnet circuit section, both ends of the series circuit in the first stage charge / discharge circuit, or the first stage charge / discharge circuit. In other words, the capacitor is connected between both ends of the capacitor.

  Further, when there are two or more subsequent stage charge / discharge circuits, the subsequent stage charge / discharge circuit further includes both ends of the series circuit in the previous stage charge / discharge circuit among the subsequent stage charge / discharge circuits or the previous stage charge / discharge. There is an aspect in which the capacitor is connected between both ends of the circuit.

For the configuration of the trigger control circuit,
A current waveform measuring instrument for measuring the waveform of the pulse current flowing in the circuit portion of the load electromagnet;
Current waveform recording means for recording data of a pulse current waveform measured by the current waveform measuring instrument;
From the data recorded by the current waveform recording means, the peak value of the flat top part of the pulse current waveform and the slope of the main part of the waveform are calculated, and the first capacitor with respect to the first stage capacitor is calculated according to the difference between the peak value and the target peak value. Current waveform calculation means for calculating a second charging voltage compensation value and a trigger timing compensation value for the capacitor and switch of each subsequent stage according to the inclination of the waveform main part,
A charging voltage control circuit for compensating a charging voltage setting value to be applied to the charger by the first charging voltage compensation value and the second charging voltage compensation value calculated by the current waveform calculation unit;
A trigger timing adjustment circuit for sending each trigger signal with the time difference;
It is preferable that the apparatus includes a time difference control circuit that compensates for the time difference given to the trigger timing adjustment circuit using the trigger timing compensation value calculated by the current waveform calculation means.

When configured in this way, the following effects are exhibited. That is, the current waveform measuring means measures the waveform of the pulse current flowing in the circuit portion of the load electromagnet in response to the fluctuation phenomenon of the pulse current waveform caused by the change of the circuit constant accompanying the temperature change during operation, and the current waveform recording means Records the pulse current waveform data. Then, the current waveform calculation means calculates the peak value of the flat top portion of the pulse current waveform and the slope of the main portion of the waveform from the recorded pulse current waveform data, and then calculates the difference between the peak value and the target peak value. In accordance with the first charge voltage compensation value for the capacitor of the first stage, and further, the second charge voltage compensation value and the trigger timing compensation value for the capacitor and switch of each subsequent stage according to the slope of the waveform main part. And calculate. At the same time, the charging voltage control circuit compensates the charging voltage setting value given to the charger by the first and second charging voltage compensation values. The trigger timing adjustment circuit adjusts the time difference between the trigger signals in order to improve the flatness of the flat top portion of the pulse current waveform flowing in the circuit portion of the load electromagnet. In summary, the charging voltage set value is compensated in the direction to cancel the change in the peak value, and the time difference between the trigger signals for closing the switches of the first stage and each subsequent stage is compensated in the direction to cancel the change in the slope of the waveform main part. In addition, the charging voltage setting value is compensated so as to cancel the change in the peak value due to the change in the time difference of the trigger signal, so that the fluctuation of the pulse current waveform can be sufficiently reduced to automatically optimize the pulse current waveform. It becomes possible.

  Further, the current waveform measuring device is a pulse current transformer, and the current waveform computing means is time-integrated with respect to the instantaneous value of the pulse current waveform recorded by the current waveform recording means. There is an aspect in which a quotient value obtained by dividing the value by the time constant of the pulse current transformer is added and compensated. If comprised in this way, the peak value with respect to a pulse current waveform will be evaluated more accurately, and it will become possible to implement a correct compensation calculation further.

  The current waveform calculation means performs a curve fitting calculation by the least square method when calculating the peak value of the flat top portion of the pulse current waveform and the inclination of the waveform main portion from the data recorded by the current waveform recording means. There is also an aspect of being configured as described above. If comprised in this way, it will become possible to remove the influence of the noise superimposed on a measurement waveform, and to evaluate more correctly the crest value and the inclination of the waveform principal part from a pulse current waveform.

  The switches of the charge / discharge circuits are thyristors, and the trigger control circuit is based on the first and subsequent pulse transformers for applying gate pulses to the gates of the thyristors and the input of excitation trigger signals. Outputs excitation trigger signals to the first and subsequent stage gate drive circuits that output gate pulses to the first and subsequent stage pulse transformers, and to the first and subsequent stage gate drive circuits. It is also preferable to adopt a configuration including a trigger timing adjustment circuit capable of adjusting the time difference between the two.

  Hereinafter, embodiments of a pulse power supply device according to the present invention will be described in detail with reference to the drawings.

[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 diagram showing a voltage / current waveform of each part of the pulse power supply device and a pulse current waveform flowing in a load electromagnet. .

  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. The first stage charging / discharging circuit connected between both ends of the load electromagnet 10 (series circuit of the inductance component 11 and the resistance component 12) by connecting the switches S1 in series. This is a subsequent stage charge / discharge circuit in which the waveform adjusting coil L2 is connected in series and connected between both ends of the load electromagnet 10. In the case of the present embodiment, the number of stages of the charge / discharge circuit 22 in the subsequent stage is one. As for the switches S1 and S2, a thyristor that automatically extinguishes with the reversal of the current direction is used in this embodiment, but it may be replaced with another control switching element.

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 switch S1, 34 is a subsequent stage gate drive circuit, and 35 is This is a subsequent stage pulse transformer for closing the subsequent stage switch S2. 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 whose output voltage can be adjusted, D1 is a protective diode, and R1 and R2 are charging resistors. The protection diode D <b> 1 is connected between both ends of the output voltage variable charger 40. 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 the negative terminal of the output voltage variable type charger 40. Connected to the terminal. Further, the positive terminal of the output voltage variable charger 40 is connected to the positive terminal of the capacitor C2 in the subsequent stage via the charging resistor R2 in the subsequent stage, and the negative terminal of the capacitor C2 is charged in the output voltage variable type. The negative terminal of the container 40 is connected.

  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 output voltage variable type charger 40 via the first-stage charging resistor R1, and the subsequent-stage capacitor C2 is charged via 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 switch S1 via the first-stage pulse transformer 33, and the first-stage switch S1 is turned on. Further, after the predetermined time difference T _S2 , the succeeding stage gate drive circuit 34 to which the trigger signal T2 is inputted outputs a gate pulse to the succeeding stage switch S2 via the succeeding stage pulse transformer 35, and the succeeding stage switch. Turn on S2. The predetermined time difference T _S2 is opened between the turn-on timing of the first-stage switch S1 and the turn-on timing of the subsequent-stage 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, as described as a problem in the conventional example, the load electromagnet is increased by increasing the charge voltage setting command signal given to the output voltage variable charger 40. There is a concept of compensating for a decrease in the peak value of the current i ₃ . 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.

Therefore, in the present embodiment, a trigger timing adjustment circuit 31 is provided that provides an adjustable time difference T _S2 for the two trigger signals T1 and T2 that close the first-stage switch S1 and the subsequent-stage switch S2. Yes. The slope of the current in the flat top portion F is adjusted (corrected) by adjusting the time difference T _S2 between the trigger signals T1, T2 so as to increase as the temperature rises.

As shown in FIG. 2 showing the voltage / current waveform of each part of the pulse power supply device and the change of the pulse current waveform flowing in the load electromagnet 10, the resistance value of the circuit of the load electromagnet 10 is changed from 20 mΩ to 20.9 mΩ and 21.8 mΩ. As it increases, the time difference T _S2 (indicated as “TS2” in FIG. 2C) for igniting the switch S2 in the subsequent stage is gradually increased from 0 μs to 2 μs and 4 μs, and at the same time, the output voltage is varied. By gradually increasing the charging voltage of the type charger 40 from 969.00 V to 971.56 V and 974.12 V, the variation 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.

As described above, in this embodiment, the time difference T _S2 is increased as the charging voltage of the output voltage variable charger 40 increases as the temperature rises. The flatness of the current in the flat top portion F can be improved.

[Second Embodiment]
FIG. 3 is a circuit diagram showing the configuration of the pulse power supply device according to the second embodiment of the present invention. In FIG. 3, the same reference numerals as those used in FIG. 1 of the first embodiment denote the same components, and a detailed description thereof will be omitted. In the present embodiment, a current waveform measuring instrument 51, a current waveform recording means 52, a current waveform calculating means 53, a charging voltage control circuit 54, and a time difference control circuit 55 are added as new components 30a in the trigger control circuit 30. Yes.

  The current waveform measuring instrument 51 has a function of measuring the waveform of the pulse current flowing in the circuit portion of the load electromagnet 10, and a pulse current transformer (Pulse Current Transformer) is used here as an example. In addition to the pulse current transformer, a Rogowski coil, a direct current transformer, or the like can be used as the current waveform measuring instrument 51.

  The current waveform recording means 52 has a function of recording the pulse current waveform data measured by the current waveform measuring instrument 51. Here, as an example, the current waveform recording means 52 is recorded as digital data by a digitizer using an analog-digital converter. Use what you want.

The current waveform calculation means 53 calculates the peak value H of the flat top portion F and the slope m of the waveform main part of the pulse current waveform from the data recorded by the current waveform recording means 52, and the peak value H and the target peak value Ho. The first charging voltage compensation value V _C1 is calculated according to the difference ΔH (Ho−H) between the second charging voltage _Vc2 and the trigger timing compensation value Δt according to the slope m of the waveform main part. It has a function to calculate More details are as follows.

That is, the current waveform calculation means 53 is a value obtained by integrating the instantaneous value of the instantaneous value of the pulse current waveform recorded by the current waveform recording means 52 with respect to the current waveform measuring device 51. It has a function of adding compensation values of the quotient obtained by dividing a time constant _{(i t → i t + ∫i} t dt / τ). This function compensates for the time drop (sag or droop) at the top of the measured pulse waveform, which is a characteristic of the pulse current transformer, and evaluates the peak value and the slope of the waveform main part for the true pulse current waveform to make it more correct. Compensation calculation can be performed. Furthermore, as a calculation method of the previous, the slope m of the pulse height H and waveform main part of the flat top portion F of the pulse current waveform for performing the time integration (∫i _t dt), for the noise removal, the minimum It is preferable to use a curve fitting operation by the square method. The current waveform calculation means 53 is configured in a digital calculation system using a microprocessor, a DSP (digital signal processor), a logic reconfigurable FPGA (Field Programmable Gate Array), or the like.

The charging voltage control circuit 54 is a charging voltage setting value to be given to the output voltage variable charger 40 by the first charging voltage compensation value V _C1 and the second charging voltage compensation value V _C2 calculated by the current waveform calculation means 53. It has a function of compensating for Vc. The charging voltage control circuit 54 is _supplied with a charging voltage setting command signal S _cv as in the conventional example. The first charging voltage compensation value V _C1 and the second charging voltage compensation value V _C2 are added to the charging voltage setting value Vc indicated by the charging voltage setting command signal S _cv . As a result, the peak value H of the flat top portion F of the pulse current waveform flowing in the circuit portion of the load electromagnet 10 is optimized.

The time difference control circuit 55 compensates for the time difference T _S2 given to the trigger timing adjustment circuit 31 using the trigger timing compensation value Δt calculated by the current waveform calculation means 53.

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

  Charger 40, charging resistors R1, R2, first stage capacitor C1 and subsequent stage capacitor C2, trigger timing adjustment circuit 31, first stage gate drive circuit 32 and subsequent stage gate drive circuit 34, first stage pulse transformer 33, The operations of the pulse transformer 35 at the subsequent stage, the switch S1 at the first stage, and the switch S2 at the subsequent stage are the same as those in the previous embodiment.

The waveform of the pulse current flowing through the circuit portion of the load electromagnet 10 is measured by the current waveform measuring device 51 and recorded in the current waveform recording means 52. Further, the current waveform calculation means 53 calculates the peak value H of the flat top portion F of the pulse current waveform recorded in the current waveform recording means 52 and the slope m of the waveform main portion. In this calculation, waveform fitting using the least square method or the like is performed. This is because the current waveform measured by the current waveform measuring instrument 51 inevitably includes noise. As an example of the waveform fitting, a pulse function waveform flowing through the load electromagnet 10 is calculated by a least square method or the like using a time function f (t) shown in Formula (1) as a time function f (t), and a coefficient a _{0 of} a time function that closely approximates the waveform. , A _k is preferred.

ノイズを除去した電流波形が数式（１）で表されるとして、時刻ｔ₀ における値a₀ を電流波高値Ｈの近似値として採用し、次回の充電電圧を決定するためのフィードバック値として用いる方法がある。

Assuming that the current waveform from which noise has been removed is expressed by Equation (1), the value a ₀ at time t ₀ is adopted as an approximate value of the current peak value H, and used as a feedback value for determining the next charging voltage. There is.

Further, a value A obtained by integrating the mathematical formula (1) over the flat top portion time length T around the time t = t ₀ is given by the mathematical formula (2). Since this is considered to be a better approximation of the average value of the current value during this period, there is a method of using this value as a feedback value for determining the next charging voltage.

また、電流波形フラットトップ部Ｆの波形要部の傾きｍを計算する有力な方法として次のようにするのが好ましい。すなわち、数式（１）の関数ｆ（ｔ）の時刻ｔ＝ｔ₀ ＋Ｔ／２における値ｆ（ｔ₀ ＋Ｔ／２）と時刻ｔ＝ｔ₀ −Ｔ／２における値ｆ（ｔ₀ −Ｔ／２）との差Ｂ（＝ｆ（ｔ₀ ＋Ｔ／２）−ｆ（ｔ₀ −Ｔ／２））は数式（３）のように表すことができる。この数式（３）による値Ｂ（一定時間Ｔでの波高値の差分）を近似的に傾きｍを表す数値として採用する。

Further, it is preferable to perform the following as an effective method for calculating the inclination m of the waveform main portion of the current waveform flat top portion F. In other words, time t = t ₀ + T / 2 in the value _{f (t 0 + T / 2} ) and the time t = t ₀ -T / 2 in the value f in Equation (1) function f (t) of (t ₀ -T / The difference B from 2) (= f (t ₀ + T / 2) −f (t ₀ −T / 2)) can be expressed as shown in Equation (3). A value B (difference in peak value at a fixed time T) according to the mathematical formula (3) is approximately adopted as a numerical value representing the slope m.

そして、数式（４）に示すように、前述の後続段のスイッチＳ２を点弧させるタイミングの時間差Ｔ_S2の調整量Δｔをこの傾きｍである値Ｂを用いて計算するのが良い。数式（４）において、ｃ₁ は、時間差Ｔ_S2の調整量Δｔに関して、電流波形フラットトップ部Ｆの波形要部の傾きｍ（近似値Ｂ）で補償するための係数である。

Then, as shown in Equation (4), it is preferable to calculate the adjustment amount Δt of the time difference T _S2 of the timing for firing the switch S2 in the subsequent stage using the value B that is the slope m. In Equation (4), c ₁ is a coefficient for compensating for the adjustment amount Δt of the time difference T _S2 by the slope m (approximate value B) of the waveform main portion of the current waveform flat top portion F.

さらに、後続段のスイッチＳ２を点弧させるタイミングの時間差Ｔ_S2を調整することに伴って波高値Ｈが変化するが、この波高値Ｈの変化を補償するために、充電器４０に対する充電電圧設定値Ｖｃをさらに補償する必要があり、このための調整値ΔＶc を数式（５）で計算するのが良
い。数式（５）においてｃ₂ は、上記の波高値Ｈの変化を充電電圧により補償するための係数である。

Furthermore, the peak value H changes as the time difference T _{S2 of the} timing for firing the switch S2 in the subsequent stage is adjusted. In order to compensate for the change in the peak value H, the charging voltage setting for the charger 40 is set. The value Vc needs to be further compensated, and the adjustment value ΔVc for this purpose is preferably calculated by the equation (5). In Equation (5), c ₂ is a coefficient for compensating the change in the peak value H by the charging voltage.

以上のように、本実施例によれば、測定波形に重畳するノイズの影響を除去し、波高値の変化を打ち消す方向に充電電圧設定値を補償し、波形要部の傾きの変化を打ち消す方向に初段および後続段のスイッチを閉路させる各々のトリガ信号の時間差を補償し、かつトリガ信号の時間差の変化に伴う波高値の変化を打ち消すように充電電圧設定値を補償するので、パルス電流波形の変動を充分に低減して自動的にパルス電流波形を最適化することができる。

As described above, according to the present embodiment, the influence of noise superimposed on the measurement waveform is removed, the charge voltage setting value is compensated in the direction to cancel the change in the peak value, and the change in the inclination of the waveform main part is canceled. Because the time difference of each trigger signal that closes the switch of the first stage and the subsequent stage is compensated, and the charging voltage set value is compensated so as to cancel the change of the peak value accompanying the change of the time difference of the trigger signal, the pulse current waveform The pulse current waveform can be automatically optimized by sufficiently reducing fluctuations.

  In the above-described two examples, the circuit configuration is a two-stage capacitor waveform forming circuit. However, the present invention is not limited to this, and a charge / discharge circuit having two or more stages is used as a subsequent stage charge / discharge circuit. It may be connected in parallel. The first stage charging / discharging circuit and the two or more stages charging / discharging circuits are configured to be activated with a time difference from each other, and each time difference can be adjusted.

  Further, with respect to one stage or two or more stages of subsequent stage charge / discharge circuits, the connection destination may be between both ends of the capacitor in the first stage charge / discharge circuit.

  In addition, two or more subsequent stages of charge / discharge circuits may be connected to both ends of the capacitor in the previous stage charge / discharge circuit, or both ends of the series circuit of the capacitor and switch in the previous stage.

  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.

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 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 L2 Waveform adjustment coil S1 First stage switch S2 Subsequent stage switch

Claims (7)

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 comprising a series circuit of a first stage capacitor and a first stage switch, capable of discharging the charging power of the first stage capacitor to the circuit portion of the load electromagnet,
It comprises a series circuit of a succeeding stage capacitor, a succeeding stage switch, and a waveform adjusting coil, and includes at least one following stage charging / discharging circuit capable of discharging the charging power of the succeeding stage capacitor to the circuit portion of the load electromagnet. With
Charge the first stage capacitor and the subsequent stage capacitor, a charger capable of adjusting the charging voltage setting value,
Sending trigger signals independent of each other to close the first-stage switch and the subsequent-stage switch. By adjusting the time difference between the trigger signals , the pulse current waveform flowing in the circuit portion of the load electromagnet A pulse power supply device comprising a trigger control circuit capable of improving flatness of a flat top portion . The first stage charge / discharge circuit is connected between both ends of the circuit portion of the load electromagnet,
The subsequent stage charge / discharge circuit is connected between both ends of the circuit portion of the load electromagnet, both ends of a series circuit in the first stage charge / discharge circuit, or both ends of a capacitor in the first stage charge / discharge circuit. The pulse power supply device described.   In the case where the number of the subsequent stage charging / discharging circuits is two or more, the subsequent stage charging / discharging circuit further includes both ends of the series circuit in the preceding stage charging / discharging circuit among the subsequent stage charging / discharging circuits or the preceding stage charging / discharging. The pulse power supply device according to claim 2, which is connected between both ends of a capacitor in the circuit. The trigger control circuit includes:
A current waveform measuring instrument for measuring the waveform of the pulse current flowing in the circuit portion of the load electromagnet;
Current waveform recording means for recording data of a pulse current waveform measured by the current waveform measuring instrument;
From the data recorded by the current waveform recording means, the peak value of the flat top part of the pulse current waveform and the slope of the main part of the waveform are calculated, and the first capacitor with respect to the first stage capacitor is calculated according to the difference between the peak value and the target peak value. Current waveform calculation means for calculating a second charging voltage compensation value and a trigger timing compensation value for the capacitor and switch of each subsequent stage according to the inclination of the waveform main part,
A charging voltage control circuit for compensating a charging voltage setting value to be applied to the charger by the first charging voltage compensation value and the second charging voltage compensation value calculated by the current waveform calculation unit;
A trigger timing adjustment circuit for sending each trigger signal with the time difference;
The time difference control circuit which compensates for the time difference given to the trigger timing adjustment circuit using the trigger timing compensation value calculated by the current waveform calculating means. Pulse power supply. The current waveform measuring instrument is a pulse current transformer,
The current waveform calculation means adds the quotient obtained by dividing the instantaneous value of the instantaneous value of the pulse current waveform recorded by the current waveform recording means by the time constant of the pulse current transformer. The pulse power supply device according to claim 4, which is configured to compensate.   The current waveform calculation means performs a curve fitting calculation by a least square method when calculating the peak value of the flat top portion of the pulse current waveform and the slope of the waveform main part from the data recorded by the current waveform recording means. The pulse power supply device according to claim 4 configured. Each of the switches of the charge / discharge circuit is a thyristor,
The trigger control circuit includes:
An initial stage and a subsequent stage pulse transformer for applying a gate pulse to the gate of each thyristor;
A gate drive circuit for the first stage and the subsequent stage that outputs a gate pulse to the pulse transformer for the first stage and the subsequent stage based on the input of the excitation trigger signal;
2. The pulse power supply device according to claim 1, further comprising a trigger timing adjustment circuit that outputs an excitation trigger signal to the first-stage and subsequent-stage gate drive circuits and that can adjust a time difference between the excitation trigger signals.

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