JPH0992531A - Power supply unit for pulse type electromagnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable this power supply unit to supply a pulse type current in rapid rise and fall time yet long flat time. SOLUTION: The first capacitor 22 is charged by the first rectifier 21. Likewise, the second capacitor 30 is charged by the second rectifier 31. When switches 23 and 26 are turned on, a coil 25 is supplied with a current responding to the discharge from the first capacitor 22. When the value of the current running in the coil 25 attains to a set up value, the switch 23 is turned off and a transistor 29 is turned on to supply the coil 25 with a current responding to the discharge from the second capacitor 30. Finally, when the flat top time is terminated, another switch 26 and the transistor 29 are turned off so that the energy accumulated in the coil 25 may be regenerated to the first capacitor 22 through the intermediary of diodes 27 and 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device used for exciting a pulse type electromagnet, which is arranged in a beam line in a treatment device using heavy particle beams in addition to light particle beams such as electrons or protons. The present invention relates to a power supply device used when exciting a pulse electromagnet.

[0002]

2. Description of the Related Art Conventionally, for example, a power supply device shown in FIG. 2 is known as a power supply device of this type. Referring to FIG. 2, an AC power supply (not shown) is connected to the illustrated power supply device via a rectifier 11. The illustrated power supply device includes a capacitor 12 (capacitance is C), and the capacitor 12 is connected to the rectifier 11 in parallel. The switch 13 and the diode 14 are connected in series to form a current path, and this current path is connected in parallel to the capacitor 12.

The cathode of the diode 14 is connected to one end of a coil (coil which constitutes an electromagnet) 15 (here, the inductance of the coil is L and the internal resistance is R), and the other end of the coil 15 is a diode 16 And the collector of the transistor 17. The cathode of the diode 16 is connected to the switch 13 and the capacitor 12, and the emitter of the transistor 17 is connected to the anode of the diode 14 and the capacitor 12.

Now, assuming that a voltage (V) is applied to the capacitor 12, the capacitor 12 has E _C
= Energy represented by CV ^2/2 is stored.

When the switch 13 and the transistor 17 are turned on in this state, a current corresponding to the energy stored in the capacitor 12 flows through the switch 13, the coil 15 and the transistor 17. That is, the energy stored in the capacitor 12 is transferred to the coil 15
Will be moved to.

Now, assuming that the time required for the current flowing through the coil 15 to reach a steady state (flat top) is T ₁ , T ₁ is approximately π (LC) ^1/2 / 2. That is,
After a lapse of time T ₁ after turning on the switch 13 and the transistor 17, the current flowing through the coil 15 reaches a steady state. After that, the transistor 17 shifts to the constant current operation (the current strength in the steady state is I).

Now, when a time T ₂ further elapses from the time T ₁ , if a preset time elapses or the current flowing through the coil 15 decreases, that is, if the flat top state ends, the switch 13 and transistor 17 are turned off. This makes the coil 1
The energy stored in 5 is regenerated in the capacitor 12 via the diodes 14 and 16, and after a lapse of time T ₁ from time T ₂ , the current flowing in the coil 15 becomes substantially zero. Then, the switch 13 and the transistor 17 are turned on again, and the above operation is repeated.

[0008] Here, the energy stored in the coil 15 and E _L, can be expressed by E _L = LI ^2/2. Further, since the coil 15 has the internal resistance R,
As thermal energy E _R , E _R = I ² RT ₂ + 2I ² R
T _1/3 (part of 2I ² RT _1/3 is approximated by a triangular wave) energy indicated by consumed by the coil 15. Furthermore, in the flat top, the transistor 17 has Vce ×
The thermal energy of I ² T ₂ is consumed (Vce is the voltage across the transistor 17).

[0009]

By the way, in the above power supply device, in order to increase the flat top time, in order to increase the energy stored in the capacitor 12 in consideration of the thermal energy in the coil 15, the capacitor is increased. It is necessary to increase the capacitance C of 12.
However, if the capacitance C of the capacitor 12 is increased, the rise and fall of the current flowing through the coil 15 will be delayed. On the other hand, if the voltage V across the capacitor 12 is set high in order to accelerate the rising,
Vce increases during constant current control, that is, I ² RT
There is a problem that ₂ becomes large and the transistor (constant current control element) generates heat. Further, a circuit for separately limiting the charging current is required, which complicates the circuit configuration. Further, if the voltage across the capacitor is set too high, it becomes necessary to consider the problems of withstand voltage of the element and insulation of the coil.

It is an object of the present invention to provide a power supply device for a pulse type electromagnet which can quickly rise and fall and has a long flat top time.

Another object of the present invention is to provide a pulse type electromagnet power supply device having a simple circuit configuration and a small heat generation amount.

[0012]

According to the present invention, a power supply device used for supplying a pulsed current to an electromagnet coil has a first current supply source and a second current supply source. , The first current supply source is connected to the electromagnet coil during a rising period and a falling period of the pulsed current, and the second current is supplied during a flat top period located between the rising period and the falling period. A pulse type electromagnet power supply device is provided, which is provided with a connecting means for connecting a current supply source to the electromagnet coil.

Here, for example, the first current supply source includes a first capacitor charged by a DC power supply, and the second current supply source includes a second capacitor charged by a DC power supply. The electromagnet coil is connected in parallel to the first and second capacitors. Then, the connection means first connects the electromagnet coil to the first capacitor selectively.
Switch means, second switch means for selectively connecting the electromagnet coil to the second capacitor, and the first switch means for connecting the electromagnet coil to the first capacitor. When the value of the current flowing through the electromagnet coil reaches a preset set value, the first
The switch means and the electromagnet coil and the first
And a control means for disconnecting the second condenser and connecting the electromagnet coil and the second condenser by the second switch means. Further, the control means for performing post-connection constant current control is configured such that, when a preset flat top time elapses after the electromagnet coil and the second capacitor are connected, the first and second The electromagnet coil is controlled to be separated from the first and second capacitors by a switch means, and the electromagnet is controlled when the electromagnet coil is controlled to be separated from the first and second capacitors. There is provided a regenerating means for forming a regenerative route for regenerating the energy stored in the power coil to the first capacitor. The first and second switching means may be switching transistors or field effect transistors.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings.

Referring to FIG. 1, an AC power supply (not shown) is connected to the illustrated power supply device via a rectifier 21. The illustrated power supply device includes a capacitor 22 (capacitance is C ₁ ), which is a rectifier 21.
Are connected in parallel. A shunt resistance (ammeter) 24 is connected via a switch 23, and the shunt resistance 2
A coil (coil forming an electromagnet) 25 is connected to 4 (the inductance of the coil is L and the internal resistance is R).
And). The coil 25 is connected to the capacitor 22 via the switch 26. That is, switch 2
The shunt resistor 24 and the coil 25 are connected in parallel via 3 and 26.

Further, as shown, the coil 25 is connected to the capacitor 22 through the diode 27,
The capacitor 22 is connected to the shunt resistor 24 via the diode 28. That is, the diode 27 is connected to the coil 25 on the anode side and to the capacitor 22 on the cathode side. The diode 28 is connected to the capacitor 22 on the anode side and is connected to the shunt resistor 24 on the cathode side.

As shown, the shunt resistor 24 is connected to a capacitor 30 (capacitance is C ₂ ) via a transistor 29.
5 is connected. That is, the transistor 29 has an emitter connected to the shunt resistor 24 and a collector connected to the capacitor 30. A rectifier 31 is connected in parallel to the capacitor 30, and the rectifier 31 is connected to an AC power source (not shown).

This power supply unit is provided with a controller 32, and the controller 32 performs on / off control of the switches 23 and 26, on / off control of the transistor 29, and constant current control as described later.

Now, assuming that the voltage (V ₁ ) is applied to the capacitor 22, E
energy represented by ^{_{c1 = C 1 V 1 2/}} 2 is accumulated.

In this state, when the switches 23 and 26 are turned on by the controller 32, a current (I ₁ ) corresponding to the energy stored in the capacitor 22 flows to the coil 25 via the switches 23 and 26. Become. That is,
The energy stored in the capacitor 22 moves to the coil 25. At this time, the current (I ₁ ) is the time T
_{After 11} (T ₁₁ is approximately equal to π (LC ₁ ) ^1/2 / 2), the steady state is reached (that is, rising).

The controller 32 monitors the current value (output current value) flowing through the shunt resistor 24, and when this output current reaches a preset set current value, it is determined that the steady state (flat top) is reached. When judged, the switch 23 is turned off and the transistor 29 is turned on. As a result,
Energy corresponding to the thermal energy of I ² R × flat top from the capacitor 30 (the voltage across the capacitor 30 is V ₂ ) is transferred to the coil 25 via the transistor 29.
Given to. Here, constant current control is performed by the transistor 29. That is, the current given to the coil 25 by the transistor 29 is defined as I ₁ .

After that, when the flat top time has elapsed, the controller 32 determines that the falling state has occurred, and the controller 32 turns off the transistor 29 and the switch 26. As a result, the energy stored in the coil 25 (LI ₁ ² /
2) is a capacitor 22 via diodes 27 and 28
Regenerated to.

As mentioned above, in the above example, the coil 25
When the current flowing through the capacitor reaches the flat top, the capacitor 3
Since the current is supplied from 0, V ₁ = V, I ₁
= As I, flat top, that is, if the time until the rise and T _1, the energy E _c1 stored in the capacitor 22 is equivalent to ^{(LI 2/2 + 2I 2} RT 1/3). As a result, the energy stored in the capacitor 22 can be reduced. That is, the capacitance C _{1 of the} capacitor 22 is equal to the capacitance C ₁ of the capacitor 12 shown in FIG.
It can be reduced compared to. Therefore, the time until the current flowing through the coil rises can be shortened (that is, the rise can be made faster).

As described above, in the flat top mode, the current is supplied from the capacitor 30. When the current supplied from the capacitor 30 is I, the capacitor 30
The voltage applied to RI + Vce (Vce is the transistor 2
9 (17). As a result, the rectifier 31 can be optimized. Furthermore, the length (time) of the flat top is determined by the capacitance of the capacitor 30 and the like, while the rise and fall times are determined by the capacitance of the capacitor 22, so the rise and fall times are affected by the flat top time. Never. Moreover, in the flat top mode, the voltage applied to the transistor 29 is small, so that heat generation can be suppressed.

[0025]

As described above, according to the present invention, there is an effect that the flat top time can be lengthened and a pulsed current having a fast rise and fall can be supplied to the coil (electromagnet).

[Brief description of drawings]

FIG. 1 is a circuit diagram for explaining an example of a power supply device according to the present invention.

FIG. 2 is a circuit diagram for explaining a conventional power supply device.

[Explanation of symbols]

11, 21, 31 Rectifier 12, 22, 30 Capacitor 13, 23, 26 Switch 14, 16, 27, 28 Diode 15, 25 Coil 17, 29 Switching transistor or field effect transistor 24 Shunt resistor 32 Controller

Claims (5)

[Claims] 1. A power supply device used when supplying a pulsed current to an electromagnet coil, comprising a first current supply source and a second current supply source, and a rising period and a standing period of the pulsed current. The first current supply source is connected to the electromagnet coil during a falling period, and the second current supply source is connected to the electromagnet coil during a flat top period located between the rising period and the falling period. A power supply device for a pulse-type electromagnet, comprising: 2. The pulse type electromagnet power supply device according to claim 1, wherein the first current supply source includes a first capacitor charged by a DC power supply, and the second current supply source is a DC power supply. A pulse type electromagnet power supply device comprising a second capacitor charged by a power supply, wherein the electromagnet coil is connected in parallel to the first and second capacitors. 3. The pulse type electromagnet power supply device according to claim 2, wherein the connecting means includes first switch means for selectively connecting the electromagnet coil to the first capacitor, and the electromagnet. Second coil selectively for the second
Second switch means connected to the capacitor and the first switch means connects the electromagnet coil to the first capacitor to set the value of the current flowing through the electromagnet coil to a preset value. In this case, there is provided a control means for disconnecting the electromagnet coil and the first capacitor by the first switch means and connecting the electromagnet coil and the second capacitor by the second switch means. Characteristic pulse type power supply for electromagnet. 4. The pulse type electromagnet power supply device according to claim 3, wherein the control means determines that a flat top time has elapsed after the electromagnet coil and the second capacitor were connected. Then, the electromagnet coil is controlled to be separated from the first and second capacitors by the first and second switch means, and the electromagnet coil is separated from the first and second capacitors. A pulse type electromagnet power supply device, comprising a regenerative means for forming a regenerative route for regenerating the energy stored in the electromagnet coil to the first capacitor when controlled. 5. The pulse type electromagnet power supply device according to claim 4, wherein the first and second switch means are switching transistors.