JP2000223333A - Exciter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the capacity of a power supply small by constructing series resonance circuits in load units, adding AC voltage by inserting transformers in series with inductive circuit elements, and exciting only the AC current components by the resonance circuits. SOLUTION: In an exciter, secondary windings of choke transformers 41, 42 and 43 are inserted in series with electromagnets 11, 12 and 13, and AC voltage is added from the primary side by an AC power source 1, which is connected commonly in parallel to the primary winding of each choke transformer. Although the choke transformers 41, 42 and 43 may be inserted to a choke transformer 22 side, better control is obtained when they are coupled directly to the electromagnet current. When the choke transformers are connected to the choke transformer 22 side, they are inserted by being divided into two, with respect to the resonance circuit 81. The AC power source can be divided into each choke transformer, enabling adjustment of the voltage applied to each resonance circuit. If the resonance circuit 81 for inserting a DC power supply is made plural to result in a plurality of DC power sources, it is possible to reduce the voltage applied to the load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for exciting an inductive circuit element, and more particularly to an exciting device for forming a resonant circuit by combining an inductive circuit element with a capacitor and exciting the device using resonance. It is.

[0002]

2. Description of the Related Art There are various accelerators for accelerating elementary particles such as electrons. In the synchrotron accelerator, the electromagnet current is pattern-excited as shown in FIG. 2, and the elementary particle beam is incident at a low current, and the current is increased and emitted with acceleration.

In such an accelerator, the electromagnet may need to be repeatedly excited, for example, 25 times per second, in order to increase the density of input and output.

[0004] In this case, an extremely large power source is required if the excitation is to be repeated only with the power source alone. For example, consider a case where 10 electromagnets of 10 mH are excited in series. The current at the time of incidence is 1000 A and the current at the time of emission is 800
0A. Acceleration time is 1 to repeat 25 times per second.
000 ms / 25/2 = 20 ms. Then, even if it accelerates linearly, it is 10mH only with Ldi / dt.
× 10 units × (8000A-1000A) / 20ms = 3
A voltage as high as 5000 V is required, and a voltage for resistance is added to this voltage, and a power supply as large as 8000 A is required.

As a means for solving the above-mentioned problem, there is a method in which a capacitor is connected to an electromagnet circuit to form a parallel resonance circuit to excite the circuit. An example is the High Energy Accele
JHF ACCELERATOR DESIG of rator Research Organization
It is described on pages 3-93 to 3-95 of N STUDY REPORT. The operation of such a circuit will be described with reference to FIG. In this figure, for simplicity, 10 of the above example is shown.
The case of only three electromagnets will be described. Others can be similarly connected and connected in series.

As described below, parallel resonance circuits 81, 82 and 83 are provided for each electromagnet circuit.

In FIG. 3, reference numerals 11, 12, and 13 denote electromagnets of the accelerator, and the inductance is Lm. A plurality of electromagnets may be connected in series. 2 is an electromagnet 1
This is a choke transformer for bypassing a direct current flowing through 1, 12, 13 and applying a resonant alternating current.
A tightly coupled mutual inductance circuit may be considered. The windings 311, 312, 32, and 33 on the secondary side are tightly coupled to each other, and the inductance is, when viewed from the secondary side,
Although the description is omitted, it is as if the inductances function as chokes of Lch / 2, Lch / 2, Lch, and Lch. Reference numerals 51, 511, 512, 52, and 53 denote capacitors for forming a resonance circuit, and the respective capacitances are C1, C2, C2, C, and C.

Let us consider only the resonance circuit 82. This circuit is rewritten as shown in FIG.
The parallel circuit of h and C constitute a parallel resonance circuit. The resonance angular frequency ω1 is

[0009]

The resonance circuit 81 is rewritten as shown in FIG. The winding 511 and the capacitor 511 and the winding 312 and the capacitor 512 are set so that they have the same resonance frequency.
The capacity C2 of 11,512 is determined. Inductance is L
Since ch / 2, C2 = 2CLm / (Lm + Lch). If Lch = Lm, C2 = C.

Next, a capacitor 511 and a capacitor 512
Are connected in parallel to the series circuit of. The capacitance C1 of the capacitor 512 is determined so that the combined capacitance becomes equal to C.

In the above example where C1 = C-C2 / 2 Lch = Lm, C1 = C / 2
Becomes

In this way, the circuit composed of the capacitor 51 and the electromagnet 11 also becomes a parallel resonance circuit at the same resonance angular frequency as described above. For this reason, the point to which the DC power supply 6 is connected becomes a node of resonance, and a resonance AC current hardly flows there. For this reason, the DC power supply 6 can excite the electromagnets 11 to 13 via the winding 311, the electromagnet 11, the winding 33, the electromagnet 13,... . Considering that the DC power supply 6 is excluded, the resonance circuit 81 is a parallel resonance circuit having the same resonance frequency as a whole, and thus functions in the same manner as the other resonance circuits 82 and 83.

If an AC current is supplied from the AC power supply 1 via the winding 30 so as to excite the parallel resonance, a large AC current can be supplied to the electromagnets 11 to 13 even with a small-capacity power supply. . As described above, a DC current flows through each electromagnet, and a resonant AC current is added to the DC current.
Can be passed. As a result, the electromagnet can be excited at a required repetition, and an accelerator capable of accelerating at a high repetition can be realized. In this case, the accelerator and the entire power supply can be considered as a single resonance exciter.

[0015]

However, in such a resonance excitation device, the AC power supply 1 must function as a current source to excite parallel resonance. That is, if the power supply 1 is a voltage source, the primary side circuit will be in parallel when viewed from the secondary side of the choke transformer, and the resonance circuit will be different. Since this was conventionally configured with a pulse power supply, the effect was only the pulse energizing period, and there was no problem. However, there is a problem of harmonics generated by a pulse power supply, and in recent years, a sine wave power supply has been desired. In this case, the general AC power supply functions as a voltage source, so that application becomes difficult.

One method for solving this problem is to use a power source having current source characteristics or to provide current source characteristics by control. However, a current-source conversion device called a current-source conversion device has a poor sine-wave current output characteristic and is not very common. Therefore, a power supply having current source characteristics cannot be used. Further, when the current source characteristic is provided by the control, the control response is deteriorated, so that the method cannot be applied. In particular, it is not applicable when changing the resonance frequency.

Another method for solving this is as follows.
This is a method using series resonance as described in JHF ACCELERATOR DESIGN STUDYREPORT. FIG. 7 shows the circuit. In this case, the parallel resonance circuit is connected in series with the power supply 61.
Function as a series resonance circuit. The power supply 61
An AC voltage is generated while a DC current is flowing to excite the AC current in the series resonance circuit.

The problem of this method is that the power supply 61 needs a capacity of a peak value of a composite value of required values of AC and DC for both current and voltage. For example, when a current as shown in FIG. 6 is passed, the DC component is 4500 A and the AC component is 3500 A, but the power source must have a capacity of 8000 A which is the sum of them. Since the AC voltage is similarly added, the power supply capacity is about twice as large as the total capacity when the DC power supply and the AC power supply are divided.

[0019]

In the excitation device according to the present invention, a series resonance circuit is formed in the load device, a transformer is inserted in series with the inductive circuit element, and an AC voltage is applied through the transformer.

According to the present invention, only the alternating current can be excited by the resonance circuit. Since the AC power supply does not need to supply DC, a small-capacity power supply can be used. In order to excite the series resonance circuit, a power supply having a voltage source characteristic can be used. Since a sine wave output power supply having a voltage source characteristic can be used, excitation with less harmonics can be performed. Since it is controlled as an AC voltage source, it can be easily used even when the resonance frequency is changed. Because of the series resonance, there is no need to change the specifications of the power supply even when the resonance frequency is changed.

[0021]

FIG. 1 shows an embodiment of the present invention. The difference from the conventional resonance excitation device of FIG.
2, 13 in series with choke transformers 41, 42, 43
The secondary winding is inserted, and an AC voltage is applied from the primary side by an AC power supply 1 commonly connected in parallel to the primary winding of each choke transformer.

The choke transformers need not always be inserted for each resonance circuit, and may be integrated at one place. However, the choke transformers are divided because the influence of unbalance is likely to occur. Of course, two sets of resonance circuits may be used as one set of resonance circuits and two sets may be inserted as a unit.

The choke transformers 41, 42, 43 may be inserted on the choke transformer 22 side, but better control is possible if they are directly coupled to the electromagnet current. When connecting to the choke transformer 22 side, it is desirable to insert it into the resonance circuit 81 in two parts in order to improve the balance. The choke transformer 22 does not necessarily couple each winding tightly to each other, and may be an individual reactor. However, this is preferable in order to suppress parasitic vibration.

The AC power supply may be divided for each choke transformer, and the voltage applied to each resonance circuit can be adjusted. Also, it may be divided into multiple choke transformers,
The capacity of the individual power supply can be divided into appropriate sizes.

Resonant circuit 81 for inserting DC power supply
May be divided into plural DC power supplies. This makes it possible to share the DC voltage and reduce the voltage applied to the load.

FIG. 8 shows another embodiment of the present invention. In this embodiment, the primary windings of the choke transformers 41, 42, 43 are connected in series and connected to the AC power supply 20. In this case, there is an advantage that the voltage to be inserted is automatically shared according to the imbalance of the load resonance circuit.

Consider what happens to the applied voltage in the resonance excitation device according to the present invention. For simplicity of description, a series resonance circuit including an inductance L, a resistance R, and a capacitor C will be described. When exciting the current I at the angular frequency ω, the required exciting voltage U is

Given by If ω matches the resonance frequency, U = RI. This is the same even when the resonance frequency is changed by changing the capacitor, as long as the excitation frequency is changed accordingly. Inductance L, its series resistance R
In the case of a parallel resonance consisting of an inductive circuit element consisting of a capacitor and a capacitor, when the resonance frequency is changed, the voltage must be changed in proportion to the frequency, whereas the method according to the present invention makes it easy to change the frequency. There is a feature that can be.

FIG. 9 shows an embodiment of the present invention in which the resonance frequency of the load is changed. Capacitor 521 and switch 7
The capacitance ratio of the capacitor 522 connected in parallel to the capacitor 521 through the capacitor 2 is, for example, 1: 3. The capacity ratio when the switch 72 is closed and when it is opened is 1: 0.
25, and the resonance frequency is 1: 2. The capacitance of other capacitors, that is, the resonance frequency, can be similarly switched by a switch. If the frequency of the electromagnet 12 is changed in accordance with the switching, the excitation with the changed frequency can be easily performed. Since the power supply has a voltage source characteristic, it is easy to change the frequency. It is also easy to perform a two-resonance operation using an electronic switch as a switch every half cycle, and a low frequency during acceleration and a high frequency during reset.

The number or set of circuit elements in each embodiment is not limited to the number shown in the embodiment but can be changed as appropriate.

[0031]

According to the present invention, a series resonance circuit is formed in a load device, a choke transformer is inserted in series with an electromagnet,
Since the AC voltage is applied via this, only the AC current can be excited by the resonance circuit. Since the AC power supply is separated from the DC power supply, a small-capacity power supply can be used. Further, a power source having a voltage source characteristic can be used for exciting the series resonance circuit. Since a power supply having a sine wave output can be used as a power supply having a voltage source characteristic, excitation with less harmonics can be performed. Since it is controlled as an AC voltage source, it can be easily used even when the resonance frequency is changed. Because of the series resonance, there is no need to change the specifications of the power supply even when the resonance frequency is changed.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention.

FIG. 2 is a diagram for explaining a current flowing through an electromagnet in the accelerator.

FIG. 3 is a diagram for explaining a conventional technique.

FIG. 4 is a supplementary diagram (1) for explaining a conventional technique.

FIG. 5 is a supplementary diagram (2) for explaining a conventional technique.

FIG. 6 is a diagram for explaining a current when an electromagnet current is supplied at a high repetition frequency.

FIG. 7 is a diagram for explaining another conventional technique.

FIG. 8 is a diagram for explaining another embodiment of the present invention.

FIG. 9 is a view for explaining still another embodiment of the present invention.

[Explanation of symbols]

1,20 ... AC power supply, 2,21,22,41,42,4
3: Choke transformer, 6: DC power supply, 11, 12, 13
... Electromagnets, 30, 32, 33, 310, 311, 312
... Coil transformer windings, 50,51,52,53,5
11,512,521,522,531,532,51
01, 5102, 5111, 5112, 5121, 51
22: capacitor, 61: AC / DC common power supply, 71,
72, 73, 711, 712... Switches, 81, 82,
83, 810: Resonant circuit.

Claims (9)

[Claims] In a load device constituted by an inductive circuit element and a capacitor, forming a series resonance circuit, a secondary winding of a transformer is inserted in series with the circuit, and an alternating current is applied to a primary side of the transformer. An exciter characterized in that a power supply is connected and a resonance frequency is applied to a resonance circuit by applying a voltage near the resonance frequency, thereby exciting an inductive circuit element. 2. A load apparatus according to claim 1, wherein a plurality of sets of load devices constitute a series resonance circuit composed of an inductive circuit element and a capacitor, and the series resonance circuits are connected so as to form a loop in series. An exciting device comprising the same number of transformers as the load device, secondary windings of each transformer being inserted in series with each load device, and an AC power supply connected to the primary winding. . 3. An exciter according to claim 2, wherein the primary windings of each transformer are connected in parallel, and an AC power supply is connected thereto. 4. An exciter according to claim 2, wherein the primary winding of each transformer is connected in series and an AC power supply is connected thereto. 5. The load device according to claim 1, wherein the set of load devices includes at least two inductive circuit elements connected in series, and a capacitor is connected in parallel to at least one inductive circuit element. An exciting device characterized in that a series resonance circuit is formed by series connection of an inductive circuit element to which no capacitor is connected and an inductive circuit element to which a capacitor is connected in parallel. 6. The inductive circuit element according to claim 5, wherein a DC power supply is provided in series with the inductive circuit element, and a DC current can be supplied to the inductive circuit element, and an AC excitation is performed while supplying the DC current. Exciting device. 7. An exciter according to claim 1, wherein the resonance frequency is made variable by switching the capacitance of the capacitor, and the frequency of the AC voltage to be applied can be switched at the same time. 8. The inductive circuit element according to claim 5, wherein there are at least two sets of load devices constituting a resonance circuit, and the inductive circuit elements of each load device to which a capacitor is connected in parallel are magnetically dense. An exciter characterized by being coupled to the exciter. 9. An accelerator using the exciter according to claim 1.