JPH0653061A - Direct-current transformer - Google Patents

Abstract

PURPOSE:To realize a direct-current transformer having stabilized electrical characteristics from Hole elements by a method wherein a sheetlike belt is turned along the outer periphery of a core while both ends of the belt are connection-fixed using a spring having specific spring constant. CONSTITUTION:Within a sheetlike belt 51, Hole elements 21,22 are held by the cut off surfaces of a core 10 to be turned along the outer periphery of the core 10 so as to be fixed and held without interposing a buffer member such as bonding agent, etc. On the other hand, blocks 52, 53 having engagement holes are provided on both ends of the belt 51. Besides, a spring 54 having specific constant is engaged with the engagement holes of the blocks 52, 53 on both ends of the belt 51. Through these procedures, the title direct-current transformer having stabilized characteristics can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC current transformer, and more particularly to improvement of a DC current transformer.

[0002]

2. Description of the Related Art A DC current transformer according to the present invention relates to an improvement of Japanese Patent Application No. 63-2258 (hereinafter referred to as a prior application), which has been filed by the applicant of the present application. First, the outline of the prior application will be described.

FIG. 2 is an electric circuit diagram of the core portion. In FIG. 2, reference numeral 10 is an annular core having a pair of voids 11 and 12, and both voids are formed at point symmetrical positions on the core. Reference numerals 21 and 22 denote Hall elements arranged in the voids 11 and 12, respectively, having uniform characteristics. Reference numerals 31 and 32 denote cores 1.
The primary and secondary windings are wound around 1 and 12.

FIG. 3 is a connection diagram of an electric circuit portion. Figure 3
2, 10 is the core shown in FIG. 2, 21 and 22 are also Hall elements, 31 and 32 are primary and secondary windings, and 41 and 4
2 is an operational amplifier, 51 and 52 are constant current sources, and 60 is a summing amplifier. The output terminal of the summing amplifier 60 is connected to the output terminal 70 via the secondary winding 32 wound around the core 10. The current terminals of the Hall elements 21 and 22 are connected to the output terminals of the operational amplifiers 41 and 42 and the constant current sources 51 and 52, and the voltage terminals thereof are connected to the input terminals of the operational amplifiers 41 and 42 and the resistance elements 61 and 62. It is connected to 60.

In the DC current transformer having such a structure, the magnetic flux generated by supplying the current i1 to the primary winding 31 passes through the core 10 as shown by the arrow in FIG. Due to the magnetic flux, the Hall elements 21, 22 to which the constant currents are supplied by the constant current sources 51, 52 generate a voltage corresponding to the current i1 at their voltage terminals. The generated voltage is applied to the operational amplifiers 41 and 42,
The single-ended outputs of the operational amplifiers 41 and 42 are added by the adding amplifier 60. The output of the summing amplifier 60 is supplied to the secondary winding 32, and the current i2 flows through the secondary winding 32. The magnetic flux generated in the core 10 by the current i2 goes around the core 10 so as to cancel the magnetic flux in the direction of the arrow in FIG. The adding amplifier 60 controls the value of the current i2 so that the added value of the output voltages of the Hall elements 21 and 22 which is the output of the adding amplifier 60 becomes zero. The secondary current i2 when the output of the summing amplifier 60 becomes zero corresponds to the primary current i1 and is measured from the output terminal 70.

In the DC current transformer having such a structure,
Even if an external magnetic field is applied to the core 10, the directions of the magnetic fluxes generated in the core 10 by the external magnetic field are opposite to each other. As a result, the voltages generated in the Hall elements 21 and 22 due to the external magnetic field have opposite directions, and the reverse polarity voltages are applied to the summing amplifier 60 shown in FIG. 3 and cancel each other out. Therefore, the output of the summing amplifier 60 is not affected by the external magnetic field, and the secondary current i2 has a characteristic that it accurately corresponds to the primary current i1.

FIG. 4 is a concrete configuration diagram of the above-mentioned prior application.
In FIG. 4, reference numeral 10 denotes a core, which is a rectangular ring for facilitating the winding of the primary and secondary windings. It is cut in various ways. The Hall elements 21 and 22 are formed by sandwiching a magnetic detection body in a stacked portion of two rectangular ferrite plates, and are fixed to one surface of the core after cutting with an adhesive or the like to The structure is such that the other side is sandwiched. Further, in order to fix and hold this, a thin plate-shaped belt 44 is wound around the outer periphery of the core. Belt 44
A block 45 having a screw hole 48 penetrating therethrough is fixed by welding, soldering or the like, and a block 46 having a round hole 49 larger than the screw hole 48 penetrating is fixed at the other end. Screw 47 for fastening the round holes 4 of blocks 45, 46
The core 10 and the Hall elements 21 and 22 are held by fastening them to the screw holes 48 while penetrating 9. 41 and 42 are voltage inputs and outputs of the Hall elements 21 and 22,
The lead wire used for power supply is shown in FIG.
The flexible printed board 43 is used for the input / output of 1, 22 and the like.
Done through. The flexible printed board 43 itself is attached to the core 10 with an adhesive or the like.

[0008]

However, according to the structure of the prior application, the core 10 and the Hall element 21,
There is a problem that the adhesive surface between the 22 is not necessarily flat.

Further, depending on the thickness of the belt 44 and the tightening torque of the screw 47 for fastening the belt, a force is intensively applied to the four corners of the core 10 as shown in FIG.

In any of these cases, the force is not evenly applied to the cut surface of the core 10, and the Hall elements 21, 22
No stable electrical characteristics can be obtained. The present invention is
It was made in view of such conventional problems,
Its purpose is to provide a DC current transformer in which a uniform force is always applied to the cut surface of the core even if the environment changes such as temperature, and stable electric characteristics can be obtained from the Hall element. is there.

[0011]

In a DC current transformer according to the present invention, a Hall element is arranged in a pair of air gaps formed so that primary and secondary windings are wound and are point-symmetrical. A current is supplied to the secondary winding so that a magnetic flux in a direction in which the output voltages of the pair of Hall elements are added to each other and the magnetic flux generated in the core by the primary winding is canceled is generated in this core. In a DC current transformer comprising a supply amplifier for supplying, a plate-shaped belt is circulated along the outer periphery of the core, and both ends of the belt are connected and fixed by springs having a predetermined spring constant. is there.

[0012]

The core and the Hall element are always connected and fixed with a constant force by a spring having a predetermined spring constant.

Therefore, variations in characteristics after assembly due to variations in parts are reduced, and stable characteristics can be obtained.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of an embodiment of the present invention, and portions common to FIG. 4 are assigned the same reference numerals as those in FIG. 4 and their re-explanation is omitted. In FIG. 1, reference numeral 51 denotes a plate-shaped belt, which is placed on the outer periphery of the core 10 so that the Hall elements 21 and 22 are sandwiched by the cut surface of the core 10 and fixed and held without a buffer member such as an adhesive. It is orbited along. Blocks 52 and 53 having locking holes are provided at both ends of the belt 51. As the belt 51, a belt having a thickness that does not apply unreasonable force to the four corners of the core 10 is used. Further, the flatness of the cut surface of the core 10 is set higher than in the past. Reference numeral 54 is a spring having a predetermined spring constant, which is locked in the locking holes of the blocks 52 and 53 at both ends of the belt 51. 55 is a magnet, and the Hall element 2
It is used for fixing the lead wires 41 and 42 of 1, 22 to the flexible printed board 43 when soldering them.

In the DC current transformer constructed as described above, since a buffer member such as an adhesive is not interposed between the core 10 and the Hall elements 21 and 22, the adjustment after assembling can be simplified and the one-time operation can be performed only once. The pass rate at which the desired characteristics were obtained by adjustment was improved from 69% in the past to 91%.

Further, the occurrence rate at which the Hall element, which can be presumed to be caused by screwing, becomes unusable is also improved from about 30% in the past to 5% or less. In particular, since the belt 51 is connected and fixed by the spring 54 whose spring constant is controlled, a constant force is always applied to the core 10 even if the environment such as temperature changes, and the accuracy of the DC current transformer is improved. The gap between the core 10 and the Hall elements 21, 22 that greatly influences the
Stable characteristics can be obtained.

[0017]

According to the present invention described above, the belt wound around the outer periphery of the core is connected and fixed by the spring having the specified spring constant, so that a DC current transformer having stable characteristics can be provided. .

[Brief description of drawings]

FIG. 1 is a configuration diagram of a core portion according to an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of a core portion of a DC current transformer according to the present invention.

FIG. 3 is a connection diagram of an entire circuit of a DC current transformer according to the present invention.

FIG. 4 is a configuration diagram of a core portion of the prior application.

FIG. 5 is an explanatory diagram of changes in the core portion of the prior application.

[Explanation of symbols]

 10 core 21,22 hall element 51 belt 52,53 block 54 spring

Claims (1)

[Claims] 1. An annular core, in which primary and secondary windings are wound and a hall element is disposed in a pair of air gaps formed in point symmetry, and a pair of the hall elements. A DC current transformer comprising a summing amplifier that supplies a current to the secondary winding so that a magnetic flux in a direction that cancels the magnetic flux generated in the core by the primary winding is added to the output transformer, A DC current transformer, characterized in that a plate-shaped belt is wound around the outer periphery of the belt, and both ends of the belt are connected and fixed by springs having a predetermined spring constant.