JP2001119921A - Electromagnetic pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic pump, where the unbalances present among its respective phase currents can be reduced. SOLUTION: An electromagnetic pump has a double-cylinder duct with a formed passage 3, for making a conductive fluid flow between an outside duct 2 and an inside duct 1, a plurality of laminated core blocks 4, 7 provided respectively in the outer periphery of the outside duct 2 of the double-cylinder duct and in the inner periphery of the inside duct 1 thereof, and outside- and inside- coils 6, 9 wound respectively in the slots 5, 8 of these laminated core blocks 4, 7 which form a progressive magnetic field in the passage 3 of the conductive fluid existing therein. In the electromagnetic pump, at least one of the outside- and inside-coils 6, 9 has the number of turns with its number of turns present in the outlet-side end portion of the conductive fluid is made small, relative to the number of turns present in the other portion of the conductive fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of applying a traveling magnetic field to a conductive fluid from the outside to induce an induced current in the conductive fluid and to generate a pumping action by an interaction between the induced current and an external magnetic field. The present invention relates to a three-phase AC induction type electromagnetic pump.

[0002]

2. Description of the Related Art In a three-phase AC induction type electromagnetic pump, three-phase AC windings are arranged in the order of each phase in the flow direction of the electromagnetic pump, and a three-phase AC current is supplied to the three-phase AC windings. When shed,
A traveling magnetic field is generated in the direction of the current flow. When the traveling magnetic field is caused to pass through the duct in which the conductive fluid exists, a voltage is induced in the conductive fluid by Fleming's right-hand rule, and an induced current flows. The induced current and some components of the traveling magnetic field act to generate an electromagnetic force, which acts as a pump because it receives a force to flow a conductive fluid.

As one type of three-phase AC induction type electromagnetic pump, there is an annular linear type electromagnetic pump.
(Annual Linear Induction
Pump), which is widely used in recent years because of the high reliability and safety of the duct structure.

FIG. 7 shows a basic structure of the ALIP. In this electromagnetic pump, an annulus flow path 3 is formed by a concentric double structure of an inner duct 1 and an outer duct 2 for flowing a conductive fluid such as liquid metal sodium indicated by an arrow. Further, in order to form a magnetic circuit of an AC magnetic field in the stator, a plurality of laminated core blocks 4 in which iron cores having slots 5 are stacked in the circumferential direction are arranged outside the outer duct 2 in the circumferential direction. In this case, the laminated core block 4 has a laminated surface facing the outer duct 2 and is provided radially in its entirety so that the slot 5 is located inside.

[0005] A ring-shaped outer coil (stator coil) 6 is wound in the slot 5, and a large number of the outer coils 6 are arranged in the axial direction of the laminated core block 4 so that a three-phase alternating current flows. Wired to create a magnetic field. The inside of the inner duct 1 houses a laminated core block 7 for constituting a magnetic circuit. As a result, the conductive fluid enters the electromagnetic pump from the inlet, and a voltage is induced while flowing through the annulus flow path 3 to be sent out from the outlet. On the other hand, when the internal dimensions are large, there is also a double stator type electromagnetic pump in which a slot is provided inside the laminated core block 7 and an inner coil is wound around the slot so that the discharge pressure can be obtained efficiently. is there.

[0006] By the way, U, V,
The same amount of current flows through the three-phase coil of W, but if a current that exceeds the limit of the coil through which the most current cannot flow is passed, the resistance loss of the coil in that part will be the design value. As the temperature increases, the coil generates heat, and the insulation is destroyed beyond the allowable temperature. This causes a serious problem that the coil is short-circuited and the device cannot be operated. Therefore, the current flows with the current of the phase through which the current cannot flow most among the three phases as a limit.

[0007] However, conversely, the above-mentioned limit makes it impossible to flow the current from the rated value even where the current needs to flow, thereby causing a problem that the rated operation of the device cannot be performed. Therefore, in a normal design, this U,
It is designed so that the design values of the V and W phase currents are substantially the same.

[0008]

However, in the above-described electromagnetic pump, the current imbalance between the U, V, and W phases is larger than that of conventional electric equipment. When the current imbalance between the phases becomes large in this way, the operation current is limited by the coil that can not flow the current most, and a problem occurs that a small current can be flowed to a place where the current of the other phase needs to flow more. Will be.

Further, in the case of a large electromagnetic pump, it is necessary to increase the number of parallel circuits in the same phase so that the rated voltage does not become too large. Here, when the in-phase coils are formed into a parallel circuit, simply connecting them in parallel increases the current imbalance between the parallel circuits, which also causes problems in the performance and reliability of the device.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic pump capable of reducing the inter-phase current imbalance of each phase.

Another object of the present invention is to provide an electromagnetic pump which can reduce the current imbalance between the parallel circuits when the in-phase coils are formed in a parallel circuit.

[0012]

According to the first aspect of the present invention, there is provided a double cylindrical duct in which a flow path for flowing a conductive fluid is formed between an outer duct and an inner duct. And a plurality of laminated core blocks arranged on the outer periphery of the outer duct and the inner periphery of the inner duct of the double-cylindrical duct, and the flow path in which the conductive fluid is wound around the slots of the laminated core blocks, respectively. In the electromagnetic pump having an outer coil and an inner coil for generating a traveling magnetic field, the number of turns at the outlet end of the conductive fluid of at least one of the outer coil and the inner coil is relatively reduced. Features.

According to the first aspect of the present invention, at least one of the outer coil and the inner coil has a relatively small number of turns at the outlet end of the conductive fluid, so that the U, V, and W coils have a smaller number of turns. The imbalance of the interphase current is reduced.

According to a second aspect of the present invention, in the electromagnetic pump according to the first aspect, in at least one of the outer coil and the inner coil, a plurality of coils on the upstream side from the coil at the end of the conductive fluid at the outlet side. Is smaller than the number of turns of the coil provided on the outlet side of the coil.

According to the second aspect of the present invention, the number of turns of the plurality of coils on the upstream side from the coil at the end of the conductive fluid outlet is smaller than the number of turns of the coil provided on the outlet side of the coil. Thus, the imbalance of the U, V, and W interphase currents is reduced.

According to a third aspect of the present invention, in the electromagnetic pump according to the first or second aspect, at least one of the in-phase coils of the outer coil and the inner coil is connected to every other coil or more, and the in-phase coil is connected to the other coil. The electric circuit is characterized by being divided into several groups.

According to the third aspect of the present invention, the phase current is not connected to the closest in-phase coil, but connected to every other coil of the in-phase coil at least every other coil to form a parallel circuit. Balance is reduced.

According to a fourth aspect of the present invention, in the electromagnetic pump according to any one of the first to third aspects, when a parallel circuit is formed by the in-phase coils, the coils of the number of the parallel circuits are grouped into one group. Connect one group of coils in the same order and the second group of coils in reverse order,
The in-phase coils are sequentially connected in parallel according to this regularity so as to connect the coils of the second group in the same order and the coils of the third group in the reverse order.

According to the fourth aspect of the present invention, the same-order coils of the first group and the reverse-ordered coils of the second group are connected, and the same-order coils of the second group and the third group are connected. By connecting the in-phase coils in parallel according to this regularity so as to connect the coils in reverse order, the phase current imbalance is reduced.

[0020]

Embodiments of the present invention will be described below with reference to the drawings and tables.

FIG. 1 is a sectional view showing the arrangement of coils in a first embodiment of the electromagnetic pump according to the present invention. In addition,
Parts that are the same as or correspond to those of the conventional configuration will be described using the same reference numerals. The double stator ALIP applied in each embodiment of the present invention is configured as shown in FIGS.

That is, in FIGS. 2 and 3, an annular channel 3 for flowing sodium as a conductive fluid is formed by a double cylindrical duct having an inner duct 1 and an outer duct 2 having a concentric double pipe structure. ing. In order to form a magnetic circuit of an alternating magnetic field in the stator (stator), a plurality of laminated core blocks 4 in which iron cores provided with slots 5 are stacked in the circumferential direction are arranged outside the outer duct 2 in the circumferential direction. ing. In this case, the laminated core block 4 is entirely provided so that the laminated surface faces the outer duct 2 and the slot 5 is located inside.

Inside this slot 5, a ring-shaped outer coil 6 is wound. A number of such outer coils 6 are arranged in the axial direction and are connected so that a three-phase alternating current creates a traveling magnetic field. A laminated core block 7 for constituting a magnetic circuit is housed inside the inner duct 1, and a slot 8 is provided in the laminated core block 7, and an inner coil 9 is wound and arranged in the slot 8. Thus, the discharge pressure of the conductive fluid is efficiently obtained. The electromagnetic pump configured as described above is surrounded by the frame 10. As a result, the conductive fluid enters the electromagnetic pump from the inlet, and a voltage is induced while flowing through the annulus flow path 3 to be sent out from the outlet.

FIG. 1 is a sectional view showing the arrangement of coils in a first embodiment of the electromagnetic pump according to the present invention. The first embodiment shows an example in which the number of coil phases is 84, for example. In order to facilitate understanding, at least one of the outer coil 6 and the inner coil 9 is a-1, a-2,... From the conductive fluid inlet side, and the outlet side end coil is a-84. Such coil numbers are given.

In FIG. 1, coil a-1 has a U phase, coil a-2 has a U phase, and coil a-3 has a -W phase.
The coil phases are classified into six, including the negative direction, instead of three, U, V, and W. The three phases are different even though the adjacent phases are out of phase by 120 °. On the other hand, in the case of the six classifications, the phase can be reduced as small as 60 °, and the flow of the traveling magnetic field can be made smooth. Here, coil a-1, coil a
Those in line with each other, such as -2, are called phase zones.

In the first embodiment, the coil a-1 to the coil a-80 has a coil winding number of 32 turns, and the coil a-1
The coil turns of -81 are 16 turns, the coil turns of coil a-82 are 20 turns, and the coils a-83 and a-84 are 1 turn.
The number of turns of the coil on the exit side for six turns is reduced unevenly.

That is, in the first embodiment, the number of coil turns of the first phase band from the outlet is reduced to 50% of the total number of coil turns, and the number of coil turns of the second phase band is reduced to 50% of the total number of coil turns. 62.5% respectively.

As described above, when the number of turns of the coil is reduced nonuniformly only on the outlet side, as shown in Table 1, the unbalance of the phase currents is smaller than when the coils are all wound with the same number of turns.
It can be seen that the current imbalance has decreased from 12.3% to 1.9%.

[0029]

[Table 1]

In this case, the number of coil turns of the first phase band from the outlet is reduced to 40 to 60% of the total number of coil turns, and the number of coil turns of the second phase band is reduced to 50 to 70% of the total number of coil turns. The same result was obtained even if the value was decreased.

As described above, according to the first embodiment, the number of turns of the coil at the end of the conductive fluid at the outlet side is relatively reduced, and a plurality of coils from the coil at the end of the conductive fluid at the outlet side are formed. Is smaller than the number of turns of the coil provided on the outlet side of the coil, so that U, V, W
And an electromagnetic pump in which the inter-phase current imbalance is reduced.

FIG. 4 is a coil connection diagram showing a second embodiment of the electromagnetic pump according to the present invention, FIG. 5 is a graph showing the induced voltage of each coil in the second embodiment, and FIG. FIG. 4 is an explanatory diagram for analyzing an induced voltage.

When the rated current of the electromagnetic pump increases, the power supply voltage increases. Therefore, in order to reduce the inter-phase voltage, the in-phase is a parallel circuit. In the second embodiment, the case where the total number of coils is 84 is shown. As shown in FIG. 4, among coils having the same phase, seven coils connected in series are connected in parallel.

According to the simulation, the induced voltage of each phase is wavy as shown in FIG. 5, and the undulation of the induced voltage is larger on the outlet side than on the inlet side. You can see that

The induced voltage of each coil in each phase is
It can be analyzed as follows according to FIG. That is, the voltage Vk induced in sodium as the conductive fluid at the k point is equal to the coil current Is1 of the stator (stator).
The voltage Vs created by Isn

(Equation 1) Voltage Vf generated by induced currents If1 to Ifm of sodium

(Equation 2) So, take the sum of the two

(Equation 3) Becomes

Here, the coefficient (impedance) Zkn,
Zkm is

(Equation 4)

(Equation 5) Here, in Equations (4) and (5), c is a coefficient, vk is a flow rate of sodium, Bskn and Bfkm are magnetic fields created at point k, and Φskn and Φfkm are total magnetic fluxes created from a point far from the entrance side to point k. is there.

Induced current Ifk of sodium flowing at point k
Is given by the voltage Vk induced at the location, that is, the equation (3), and the circuit resistance of sodium (for ALIP, the resistance of one round of the duct with the sodium layer mesh width) Rf

(Equation 6) Therefore, assuming that equations (3) and (6) are equal,

(Equation 7)

(Equation 8) By rewriting the coefficient (impedance) Zkk = Rf-Zkk at the k point,

(Equation 9) The formula is as follows. Since this equation (9) is an equation for the k-point of sodium, the equation (9) having the number M of sodium mesh divisions can be obtained. Therefore, since the coil current Isn of the stator (stator) is known, M equations (9) of the induced currents If1 to Ifm of sodium, which are unknowns, can be obtained. The induced currents If1 to Ifm of sodium at all places are known.

The sodium induced currents If1 to Ifm
, The magnetic flux density Bk at each point of sodium can be determined. If the magnetic flux density Bk is known, the total magnetic flux amount Φfk from the far side from the entrance side to the point k can be known. Therefore, the total magnetic flux amount Φfk
, The voltage induced in each coil of the stator (stator) is known.

Next, U, V, and W in-phase coils are connected from the conductive fluid inlet to a-1, a-2, a-3, a-4, a-5, and a-5.
a-6,..., for example, 4
When a parallel circuit is configured, a method of connecting the coils will be described.

In the U-phase, the first group includes coils a-1, a-
2, a-7 and a-8. Then, the next four second groups are coils a-13, a-14, a-19, a
−20. Coil a-1 and a-20, Coil a-2
And a-19, coils a-7 and a-14, and coils a-8 and a-13, respectively. The next four third groups are coils a-25, a-26, a-31, and a-3.
It becomes 2. Coil a-13 and a-32, Coil a-14
And a-31, coils a-19 and a-26, and coil a-2
0 and a-25 are connected respectively.

Accordingly, the coils in the same order of the first group and the coils in the reverse order of the coils of the second group are connected to each other, with the coils of the number of the parallel circuits as one group, and the coils of the second group are arranged in the same order. In-phase coils are sequentially connected in parallel according to this regularity, such as connecting coils in the reverse order of the third group.

Therefore, instead of simply connecting the coils in order in the in-phase coil, when the in-phase coils are connected as shown in FIGS. 4 and 5, the induced voltages of the seven coils connected in series are connected. Are approximately the same.

[0043]

[Table 2]

When the coils are connected as described above, as shown in Table 2, the phase current imbalance of the coils is 54.1% in the simple connection, but is 1.9 in the second embodiment. %, Which is very small.

As described above, according to the present embodiment, an in-phase coil is connected to every other coil at least every other coil, and the in-phase coil is divided into several groups to form an electric circuit. As a group, the coils of the same order in the first group and the coils of the second group in reverse order are connected, and the coils of the same order in the second group and the reverse order of the coils in the third group are connected. By sequentially connecting the in-phase coils in parallel according to this regularity, such as connecting them, when the coils are connected in parallel in the U, V, and W phases, the phase current imbalance becomes small,
Approximately the same current can flow through each coil.
Thereby, an electromagnetic pump that can be operated efficiently can be provided.

By combining the first and second embodiments, it is possible to provide an electromagnetic pump having a much smaller current imbalance.

[0047]

As described above, according to the first and second aspects of the present invention, the number of turns of the conductive fluid of at least one of the outer coil and the inner coil at the outlet end of the conductive fluid can be relatively reduced. By making the number of turns of a plurality of coils upstream from the coil at the end of the conductive fluid outlet side smaller than the number of turns of the coil provided on the outlet side from the coil, the U, V, and W interphase current amps are reduced. It is possible to realize an electromagnetic pump capable of reducing the balance, that is, it is possible to supply an approximately identical current to each coil and to provide an electromagnetic pump that can operate efficiently.

According to the third aspect of the present invention, at least one in-phase coil of the outer coil and the inner coil is connected to every other coil or more, and the in-phase coil is divided into several groups to form an electric circuit. By doing
When the coils are connected in parallel in U, V, and W, the phase current imbalance is reduced, and approximately the same current can be supplied to each coil, so that an electromagnetic pump that can operate efficiently can be provided.

According to the fourth aspect of the present invention, the same-order coils of the first group and the reverse order of the coils of the second group are connected, and the same-order coils of the second group and the third group are connected. By connecting the in-phase coils in parallel according to this regularity so as to connect the coils in reverse order, the phase current imbalance is reduced when the coils are connected in parallel in U, V, and W. In addition, it is possible to provide an electromagnetic pump that can supply substantially the same current to each coil and can operate efficiently.

[Brief description of the drawings]

FIG. 1 is a sectional configuration diagram showing a coil arrangement relationship of a first embodiment of an electromagnetic pump according to the present invention.

FIG. 2 is a sectional view showing a double stator type ALIP applied in each embodiment of the present invention.

FIG. 3 is an enlarged sectional view taken along line AA of FIG. 2;

FIG. 4 is a connection diagram of coils showing a second embodiment of the electromagnetic pump according to the present invention.

FIG. 5 is a graph showing an induced voltage of each coil in the second embodiment.

FIG. 6 is an explanatory diagram for analyzing an induced voltage of each coil in FIG. 5;

FIG. 7 is a perspective view showing the internal structure of a conventional electromagnetic pump.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inner duct 2 outer duct 3 annulus flow path 4 laminated core block 5 slot 6 outer coil 7 laminated core block 8 slot 9 inner coil 10 frame

Claims (4)

[Claims] 1. A double cylindrical duct in which a flow path for flowing a conductive fluid is formed between an outer duct and an inner duct, and arranged on the outer circumference of the outer duct and the inner circumference of the inner duct of the double cylindrical duct. A plurality of laminated core blocks, and an outer coil and an inner coil each wound around a slot of the laminated core block and creating a traveling magnetic field in the flow path in which the conductive fluid is present. An electromagnetic pump, wherein the number of turns of at least one of the inner coils at the outlet end of the conductive fluid is relatively reduced. 2. The electromagnetic pump according to claim 1, wherein in at least one of the outer coil and the inner coil, the number of turns of a plurality of coils on the upstream side from the coil at the end of the conductive fluid on the outlet side is determined by the number of coils. An electromagnetic pump wherein the number of turns of a coil provided on the outlet side is reduced. 3. The electromagnetic pump according to claim 1, wherein at least one of the in-phase coils of the outer coil and the inner coil is connected to every other coil or more, and the in-phase coils are divided into several groups. An electromagnetic pump comprising an electric circuit. 4. In the electromagnetic pump according to any one of claims 1 to 3, when a parallel circuit is formed by the in-phase coils, the coils of the number of the parallel circuits are regarded as one group, and the coils of the same order in the first group are arranged. According to this regularity, the coils are connected according to this regularity such that the coils of the second group are connected in reverse order and the coils of the second group are connected in reverse order. An electromagnetic pump in which coils are sequentially connected in parallel.