JPH0629119A - Electromagnet power supply device - Google Patents

Abstract

PURPOSE:To protect an electromagnet coil from damage caused by drastic changes in a magnetic field by gradually attenuating the electric current of the electromagnetic coil when an electric power supply is lost due to service Interruption or operational troubles in terms of an electromagnet power supply device which is designed to apply the output of a control rectifier to the electromagnet coil by way of a DC filter. CONSTITUTION:This is an electromagnet power supply device which comprises an electromagnet coil 5, a DC power supply 3, which supplies power to this coil, a DC variable power supply 6, which is connected to the electromagnet 5 in parallel by way of a diode 7, a capacitor 10-2, which is installed between output terminals of this DC variable power supply 6, a voltage detector 12-1, which detects the voltage applied to the electromagnet coil 5 and a means 13 which controls the output voltage of the DC variable power supply 6 in conformity with an output signal of the voltage detector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an accelerator coil power supply,
The present invention relates to an electromagnet power supply such as a superconducting coil power supply and a strong magnetic field coil power supply, and in particular, to provide an electromagnet power supply device capable of protecting the electromagnet coil from a mechanical force generated by a sudden change in the current of the electromagnet coil during an abnormal stop such as a power failure. It is in.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram of a conventional electromagnet power supply device. In FIG. 2, 1 is an AC power supply bus bar, 2 is a rectifier transformer that converts an AC power supply bus voltage to a desired voltage, 3 is a control rectifier that converts AC to DC, and 4 is a DC that smoothes the output of the control rectifier 3. The filter 5 is an electromagnet coil which is a load. In the case of a coil for generating a strong magnetic field for physical research, the DC rating of the power source may be 20 to 40 kA.

[0003]

The electromagnet power supply device as described above is required to have a high-speed response. In such an electromagnet power supply device, when the control rectifier 3 is stopped due to a power failure or an abnormality, the current flowing through the electromagnet coil 5 is a closed circuit composed of the electromagnet coil 5 and a DC filter 4 (not shown). The flow decreases sharply. At this time, a steep mechanical force is generated in the electromagnet coil 5 due to the abrupt change of the magnetic field accompanying the decrease of the current, so that the electromagnet coil 5 is damaged. In addition, in the case of a strong magnetic field generator, it is often used in combination with a superconducting coil, but in such a case, the superconducting coil is frequently subjected to quenciches (abrupt transition of superconductor to normal conducting state). The coil may also be damaged.

For this reason, there is a method of increasing the capacity of a capacitor (not shown) of the DC filter 4 so that the current change of the electromagnet coil 5 at the time of occurrence of an abnormality is within the allowable value. Since the response speed becomes slow, the original current control of the electromagnet coil cannot be performed normally.
That is, the high speed response is lost.

An object of the present invention is to solve the above-mentioned problems and to provide an electromagnet power supply device which does not damage the electromagnet coil even when the DC power supply is stopped at the time of power failure or abnormality.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnet coil, a DC power supply for supplying a current to the coil, and a DC variable power supply connected to the electromagnet coil in parallel via a diode. A capacitor provided between the output terminals of the DC variable power source, a voltage detector that detects the voltage applied to the electromagnet coil, and an output voltage of the DC variable power source that is controlled according to the output signal of the voltage detector. This can be achieved by providing a means.

[0007]

With the configuration described above, when the output of the controlled rectifier drops sharply due to a power failure or power supply abnormality, the diode becomes conductive and current flows from the capacitor on the DC variable power supply side to the load coil. Since this current is slowly attenuated according to the constants of the capacitor and the electromagnet coil, generation of mechanical force due to abrupt magnetic field change is eliminated, and damage to the electromagnet coil can be avoided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the configuration diagram of FIG. 1 in which the same parts as those in FIG.

The alternating current supplied from the alternating current power source bus 1 is converted into a predetermined alternating voltage through the transformer 3 for the converter, this alternating current is converted into direct current by the control rectifier 3, and the electromagnet is further passed through the direct current filter 4. Supplying a direct current to the coil 5 is the same as the conventional one.

In FIG. 2, the variable DC power supply 6 includes a transformer 8, a self-excited converter 9, and DC capacitors 10-1 and 10-.
2, bidirectional chopper circuit 11, DC voltage detector 12-2
It is composed of a constant voltage control circuit 13 and a voltage reference bias circuit 14. That is, the alternating current supplied from the alternating current power source bus 1 is converted into a predetermined alternating voltage through the transformer 8 for converter, this alternating current is converted into direct current by the self-excited converter 9, and the direct current capacitor 1
The direct current obtained between the terminals of 0-1 is bidirectional chopper circuit 1
At 1, it converts to a predetermined direct current. A DC capacitor 10-2 and a DC voltage detector 12-2 are connected between the output terminals of the bidirectional chopper circuit 11. The output of the DC voltage detector 12-1, which detects the electromagnet coil voltage, and the bidirectional chopper circuit 1
The output of the DC voltage detector 12-2 for detecting the output voltage of No. 1 is input to the voltage control circuit 13, and further the voltage control circuit 13
The output signal of the voltage reference bias circuit 14 is input to. The variable DC power supply 6 configured as described above is connected in parallel to the electromagnet coil 5 via the diode 7.

Generally, since the current of the electromagnet coil 5 is raised and lowered in the order of several seconds to several tens of minutes, the voltage of the electromagnet coil 5 also changes in the order of several seconds to several tens of minutes. Therefore, the voltage of the DC capacitor 10-2 is also controlled according to the electromagnet coil voltage detected by the DC voltage detector 12-1. In this case, as shown in FIG. 2, by adding the output signal of the voltage reference bias circuit 14 with the same polarity to the output signal of the DC voltage detector 12-2, the voltage of the DC capacitor circuit 10-2 is changed to the electromagnet coil 5-2. It is controlled by the pulse width control of the bidirectional chopper circuit 11 so that the value becomes lower than the voltage.

When the current is turned on, the self-exciting converter 9 is forward-converted to receive energy from the AC power bus 1 and
The DC capacitor 10-2 is charged through the bidirectional chopper 11. In this case, the voltage of the DC capacitor circuit 10-2 is controlled to be always lower than the voltage of the electromagnet coil 5, so that the diode 7 does not conduct.

On the other hand, when the current is turned off, the self-exciting converter 9 is operated in reverse conversion to return the energy of the DC capacitor 10-2 to the power system through the bidirectional chopper circuit 11. Also in this case, the voltage of the DC capacitor circuit 10-2 is controlled so as to be always lower than the voltage of the electromagnet coil 5, so that the diode 7 does not conduct. At this time, the bidirectional chopper circuit 11 controls the voltage of the DC capacitor 10-2, and the self-excited converter 9 controls so that the voltage of the DC capacitor 10-1 is kept constant. If the above control is performed, the DC capacitor 10-2 is connected to the diode 7 during normal operation.
Therefore, since it is always separated from the electromagnet power supply side, even if the capacitance of the DC capacitor 10-2 is increased,
Since the current control of the electromagnet coil 5 is not affected at all, it is possible to sufficiently exhibit the original high responsiveness function of the electromagnet power supply device.

However, in FIG. 2, since the voltage of the DC capacitor 10-2 becomes higher than the voltage of the electromagnet coil 5 at the time of stoppage due to power failure or occurrence of abnormality, the charge of the DC capacitor 10-2 becomes equal to that of the DC capacitor 10-2. -2
→ diode 7 → electromagnet coil 5 → DC capacitor 10
-Discharge in the closed circuit of 2. Therefore, if the capacitance of the DC capacitor 10-2 is selected to be large, the current of the electromagnet coil 5 will be slowly attenuated with a time constant determined by the constant of the electromagnet coil 5, the magnetic field change will also be slow, and a sharp mechanical force will occur. Can be prevented and damage to the electromagnet coil can be prevented.

[0015]

As described above, according to the present invention,
An electromagnet coil, a DC power supply for supplying a current to the coil, a DC variable power supply connected in parallel to the electromagnet coil via a diode, a capacitor provided between output terminals of the DC variable power supply, A voltage detector for detecting the voltage applied to the electromagnet coil, and means for controlling the output voltage of the DC variable power source according to the output signal of the voltage detector are provided, and the output voltage of the DC variable power source is set to the voltage By controlling according to the voltage detected by the output signal of the detector, the electromagnet voltage does not drop rapidly due to power failure or accident, and the current is supplied from the DC capacitor on the DC variable power supply side to the electromagnet coil through the diode. Therefore, the mechanical force is not generated due to the rapid change of the magnetic field, and the damage of the electromagnet coil can be prevented.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an electromagnet power supply device showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional electromagnet power supply device.

[Explanation of symbols]

1 ... AC power supply bus 2 ... Rectifier transformer 3 ... Control rectifier 4 ... DC filter 5 ... Load coil 6 ... DC variable power supply 7 ... Diode 8 ... Converter transformer 9 ... Self-excited converter 10 ... DC capacitor 11 ... Bidirectional chopper circuit 12 ... DC voltage detector 13 ... Constant voltage control circuit 14 ... Voltage reference bias circuit

Claims (2)

[Claims] 1. An electromagnet coil, a DC power supply for supplying a current to the coil, a DC variable power supply connected in parallel to the electromagnet coil via a diode, and an output terminal of the DC variable power supply. Device, a voltage detector for detecting the voltage applied to the electromagnet coil, and a means for controlling the output voltage of the DC variable power supply according to the output signal of the voltage detector. 2. An electromagnet coil, a DC power supply for supplying a current to the coil, a DC variable power supply connected in parallel to the electromagnet coil via a diode, and an output terminal of the DC variable power supply. Capacitor, a voltage detector for detecting the voltage applied to the electromagnet coil, and the output voltage of the DC variable power supply is lower than the output signal of the voltage detector by a predetermined value according to the output signal of the voltage detector. An electromagnet power supply device comprising means for controlling by voltage.