JPH0525717B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field This invention is directed to, for example, an optimum amperage turn of a plurality of magnetic field canceling coils disposed on a ship's hull in order to minimize hull magnetism of a ship. Regarding the decision method.

(b) Prior Art In order to cancel the magnetism of a ship's body, a plurality of coils are generally arranged in the ship's hull, and the magnetic field generated by the coils is used. However, in order to produce a cancellation effect, a magnetic field with the same waveform as the ship's magnetic field must be created by a composite magnetic field of multiple coils, and since the magnetic field of each coil affects the magnetic field of other coils, each coil It is not easy to properly adjust the current value and number of turns (ampere turns). Traditionally, to determine the ampere turns of each coil,
The magnetic field due to unit ampere turns of each coil (hereinafter referred to as the coil effect) is measured, and a composite magnetic signal of each coil effect and a reference magnetic field signal are generated so as to cancel the magnetic signal caused by the magnetic material of the ship (hereinafter referred to as the reference magnetic field). Either a method is used to compare the values and decide based on intuition, or a method is used in which each coil effect and reference magnetic field signal are appropriately divided and calculated by the method of least squares. However, the former method, which relies on intuition, is not compatible with automated systems that employ computers, and the latter method, which uses the least squares method, is theoretically capable of generating an ideal canceling magnetic field, but the coil In some cases, the value far exceeds the ampere-turn limit, making it impractical.

(c) Purpose In view of the above, it is an object of the present invention to provide a method for determining the optimum ampere turn of a coil, which can be incorporated into an automated system and which can determine the optimum ampere turn for each coil within a range that does not exceed the limit ampere turn.

(d) Configuration In order to achieve the above object, the method for determining the optimum ampere-turn of a coil according to the present invention measures the coil effect and reference magnetic field of each coil, and divides this reference magnetic field and the total coil effect of the coil into predetermined directions. death,
The ampere-turn limit value of each coil, the initial value, and the step value that is added stepwise to the initial value are set in advance. First, at each coil's initial value of ampere-turns, the reference magnetic field and the total are calculated at each division point. Calculate the difference value of the coil effect, determine whether the total coil effect exceeds the reference magnetic field and the difference value exceeds the reference value, and determine whether the ampere-turn exceeds the limit value, and If not, increase the ampere turns of each coil by a step value until it exceeds it, calculate the difference value between the reference magnetic field and the total coil effect for each increase at each division point, and check whether the difference value exceeds the reference value. and determines whether the ampere-turn exceeds the limit value, and as a result of each of the above-mentioned determinations, if the difference value at any of the dividing points exceeds the reference value or the ampere-turn exceeds the limit value,
Fix the ampere-turns of the coil corresponding to that dividing point, then increase the ampere-turns of the remaining coils by step values until all coils are fixed, and calculate the difference between the reference magnetic field and the total coil effect at the remaining dividing point. The calculation, determination of whether the difference value exceeds the reference value, and determination of whether the ampere turn exceeds the limit value are repeated.

(e) Examples The present invention will be explained in detail below using examples.

In the embodiment, as shown in FIG. 1, the ship 1 includes coils L0, L1, L2, . . . for canceling hull magnetism.
...A method of determining the optimum ampere turn for each coil when L9 is provided will be explained. In addition,
In Fig. 1, H1 represents the magnetic field of the ship 1, that is, the reference magnetic field, and H20, H21, H22...H2
9 indicates the magnetic field of each coil, and when the magnetic field H2, which is a composite of the magnetic fields of each coil, overlaps the reference magnetic field H1, ideal cancellation has been achieved. Therefore, the ampere turns of each coil is the resultant magnetic field H
2 is adjusted so that it is as close as possible to the reference magnetic field H1.

FIG. 2 is a schematic block diagram of a measurement system in which the present invention is implemented. In the same figure, D0,
D1, D2...D9 are magnetic detectors arranged on the seabed directly below the ship 1 in the direction of the bow←→stern. Detection signals from these magnetic detectors D0, D1, D2, .

Reference numeral 5 denotes a key input unit having a numeric keypad for inputting various setting values, keys for inputting designations such as reference magnetic field measurement or coil effect measurement.

The CPU 3 has functions for controlling the reference magnetic field and coil effect measurement, and further performing calculations for determining ampere turns of each coil, and these functions are executed according to a program stored in advance.

Note that the magnetic detectors D0, D1, D2...D9 are installed on the seabed as described above, but
The CPU 3, memory 4, and key input unit 5 constitute a main unit 6, which is usually placed on land.

Next, using this measurement system, each coil L
The process of determining the ampere turns of 0, L1, L2 . . . L9 will be explained with reference to the flowchart shown in FIG.

After starting the operation, first, in step ST (hereinafter abbreviated as ST) 1, the reference magnetic field H1 is measured. The measurement of this reference magnetic field H1 is performed for each coil L0, L1, L2...
Magnetic detectors D0 and D with no current flowing through L9
1, D2...D9. This magnetic detector D
The magnetic detection outputs of 0, D1, D2...D9 are stored in the memory 4 as data H10, H1, as shown in FIG.
1, H12, H13...H19 (reference magnetic field H1)
is stored as.

Next, the coil effect H2 is measured (ST2).
To measure this coil effect, apply a certain ampere turn to each coil, combine it with the reference magnetic field H1 to derive the magnetic detector output, subtract the reference magnetic field from the composite magnetic field, and store the resulting value as the coil effect. 4 is stored. The coil effects stored as data in the memory 4 are stored separately for each coil L0, L1, L2...L9 and for each magnetic detector D0, D1, D2...D9, as shown in FIG. Ampere turns of coils L0, L1, L2...L9 ATL0, ATL1...ATL9 are also key input section 5
input from each coil L0, L1, L2...L
9 is stored.

Next, in ST3, the reference value, division number, initial value, step value, ampere turns and limit ampere turns of the coil are input and set using the key input section 5.

Here, the reference value is used to compare the difference between the reference magnetic field and the absolute value of the coil effect, and is a value that is arbitrarily set to 0 or more. The initial value is the number of ampere turns given to each coil at the beginning, the step value is the number of ampere turns that increases by one step from the initial value, and the rated ampere turns is the number of ampere turns given to each coil. is the limit ampere-turns without increasing the ampere-turns of each coil.

The reference magnetic field H1 and the coil effect H2 are divided according to the division number input after inputting each setting value (ST4). FIG. 5 shows a state in which the reference magnetic field H1 and the coil effect H2 are divided. Calculation of the magnetic field and coil effect at division points where no magnetic detector exists is performed by interpolation.

First, the difference between the reference magnetic field at each dividing point P1, P2...Pn and each absolute value of the total coil effect when each coil L0, L1, L2...L9 is at its initial value is calculated (ST5). Then, it is determined whether |reference magnetic field|−|total coil effect|≧0 for each division point (ST6). If |total coil effect| is smaller than |reference magnetic field| at each division point, the judgment is
If the result is NO, it is further determined whether the ampere turns of each coil exceeds the rated ampere turns (ST7). When the initial value is given, the determination is NO, and following this determination, the ampere turns of each coil are increased by one step (ST8). As a result, the total coil effect is considered to be closer to the reference magnetic field, so here again the difference between the reference magnetic field and the absolute value of the coil effect at each division point is determined (ST9). And ST6
Then, it is determined whether the difference between the absolute values is 0 or more. At each dividing point, the difference in absolute value is 0
If the above is the case, the judgment in ST6 is YES, and in the same way as above, ST6 → ST7 → ST8 → ST9 → ST6
Repeat the process.

As the ampere turns of each coil are increased by a step amount in this way, a dividing point will eventually be reached where the total coil effect exceeds the reference magnetic field. Then, at that dividing point, the difference between the absolute value of the reference magnetic field and the coil effect is no longer 0 or more, so the determination in ST6 is NO, and then it is determined whether the absolute value of the difference is within the reference value (ST10). If the coil effect exceeds the reference magnetic field but only slightly exceeds it, the absolute value of the difference does not exceed the reference value, so the judgment in ST10 is NO, and the process moves to ST8, where the ampere-turns of each coil are further calculated. Increase by step.

When the total coil effect exceeds the reference magnetic field and the absolute value of the difference exceeds the reference value, the determination in ST10 becomes NO, and the process moves to ST11 to calculate the coil Li that has the most influence on the dividing point. In the example shown in Figure 6, the total coil effect exceeds the reference magnetic field by more than the reference value at division point P8, and coil L3
has the greatest influence on it, so in this example, coil L3 is calculated. Then, the calculated ampere-turns of the coil L3 are fixed, and the other coils are increased by one step of ampere-turns (ST12). Next, it is determined whether all the coils have been fixed (ST13), and if there are still unfixed coils, the process returns to ST6 and the processes from ST6 to ST13 are repeated with the remaining coils.
Fix the ampere turns of each coil in sequence.

As mentioned above, while repeating the process of sequentially fixing the ampere turns of each coil, even if the total coil effect is smaller than the reference magnetic field, if the ampere turns of a certain coil reaches the rated ampere turns, Since the determination in ST7 is YES, the coil is fixed at that ampere turn (ST11, ST12).

When the ampere turns of all coils are fixed (ST13), the optimum ampere turns of the coils for canceling the reference magnetic field have been determined (ST14).

According to this embodiment, although the reference magnetic field cannot be completely canceled by each coil, it can be practically canceled on average.

(f) Effects According to the method for determining ampere turns of a coil according to the present invention, the reference magnetic field and coil effect are measured, they are divided, the difference value is obtained for each division point, and the difference value and the reference value are compared. Since the ampere-turns of the coil are increased by step values from the initial value and the ampere-turns of the coil are fixed sequentially, each process can be calculated by a computer and can be automated into a system. can. Furthermore, since each coil is checked to ensure that it does not exceed its limit (rated) ampere turns, the ampere turns of the coils that cannot be realized are not determined, which is practical.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a coil installed on a ship, a reference magnetic field due to the ship, and the coil effect, Fig. 2 is a schematic block diagram of a measurement system in which this invention is implemented, and Fig. 3 is a diagram showing a measurement system using the same measurement system. A flow diagram showing the process of determining the optimum ampere turn of the coil, Figure 4 shows the data stored in the memory during measurement, and Figure 5 shows the reference magnetic field and coil effect in the processing process shown in Figure 3. FIG. 6 is a diagram for explaining the calculation of the approximate coil Li to be fixed in the same process. 1...Ship, 3...CPU, 4...Memory, 5
...Key input section, L0, L1, L2...L9...
Coil, D0, D1, D2...D9...Magnetic detector.

Claims (1)

[Claims] 1. Coils wound in a predetermined direction are arranged at arbitrary intervals in a predetermined direction, and the magnetic field generated by these coils cancels a target reference magnetic field. The optimum ampere-turn determination method involves measuring the coil effect and reference magnetic field of each coil, dividing this reference magnetic field and the total coil effect of the coil in a predetermined direction, and determining the ampere-turn limit value, initial value, and initial value of each coil. A step value that is added to the value in stages is set in advance, and the difference value between the reference magnetic field and the total coil effect is calculated for each division point at the initial value of ampere turns for each coil, and the total coil effect is exceeds the reference magnetic field and the difference value exceeds the reference value. At the same time, it is determined whether the ampere turns exceed the limit value, and if it does not exceed the limit value, the ampere turns of each coil are set to step values until the limit value is exceeded. The difference value between the reference magnetic field and the total coil effect for each increase is calculated for each division point, and it is determined whether the difference value exceeds the reference value and whether the ampere-turn exceeds the limit value. As a result of each of the above judgments, if the difference value at any division point exceeds the reference value or the ampere turn exceeds the limit value, the ampere turn of the coil corresponding to that division point is fixed, and then all coils are Increase the ampere turns of the remaining coils by the step value until they are fixed, calculate the difference value between the reference magnetic field and the total coil effect at the remaining division points, determine whether the difference value exceeds the reference value, and limit the ampere turns. A method for determining the optimum ampere turn of a coil by repeatedly determining whether the value has been exceeded.