JP2005057940A - Rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary electric machine capable of regulating the voltage between terminals depending on the relative angle of a plurality of stators by varying the relative angle during rotation depending on the rotational speed. <P>SOLUTION: In the rotary electric machine, the stator is divided into a plurality of sections in the axial direction facing the rotor wherein each divided stator is divided into the inner circumferential side and the outer circumferential side. The stator on the inner circumferential side is movable in the inner circumferential direction with respect to the stator on the outer circumferential side and provided with a coil. Voltage between terminals of the rotary electric machine can be regulated by varying the relative angle of the plurality of stators on the inner circumferential side during operation of the rotary electric machine depending on its rotational speed thereby generating a voltage corresponding to the relative angle between the coil terminals of the plurality of stators. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rotating electrical machine such as an electric motor or a generator used to supply rotational power and voltage of various devices such as an elevator, an air conditioner, and an on-vehicle device, and particularly uses a frequency variable device such as an inverter. This relates to a rotating electrical machine that performs variable speed operation.

Conventionally, many techniques have been shown to achieve high efficiency in electric motors and generators operated over a wide range from low speed rotation to high speed rotation. Among these, it has been shown that the gap between the rotor and the stator is changed in accordance with the rotational speed (the number of rotations) for the purpose of improving the efficiency at high speed rotation (for example, Patent Documents 1 and 2).
In addition, a plurality of rotors are configured, and at least one of the plurality of rotors is shifted in the rotational direction with respect to the magnetic poles of the other rotors according to changes in the rotational speed, thereby increasing or decreasing the facing area with the stator magnetic poles. Thus, it has been shown that high-speed rotation is possible (for example, Patent Document 3).

JP 2002-247822 (FIG. 1, 0015 column) Japanese Utility Model Publication No. 6-24383 (FIG. 1, 0004 column) JP 2000-20461 A (FIG. 1, 0009 column)

However, the one disclosed in Patent Document 1 relates to a power storage flywheel device having an axial gap. When applied to a general motor or the like, for example, when the output is different with the same frame number. Is a technology that needs to be changed in diameter and lacks versatility in terms of manufacturing cost, mass productivity, and the like. Further, the one disclosed in Patent Document 2 has a complicated structure in which the opposing surfaces of the rotor and the stator are conical, and has a problem that the mass productivity is poor and the manufacturing cost is high. Yes.
Further, in Patent Document 3, the rotor is relatively rotated during rotation, and moving an object during high-speed rotation requires not only high technology but also rotation balance. There is a problem that it is difficult to remove and causes vibration and noise.

  In addition to the above problems, problems related to the voltage and loss of general-purpose rotating electrical machines will be described below.

  The amount of magnetic flux linked to one turn of a coil of a certain phase provided in the stator is expressed as the following formula 1.

  Since the amount of magnetic flux changes with time, the following voltage is generated in the coil. The voltage is shown as Equation 2 below.

  Here, the maximum voltage is expressed as Vm = n · Φm · ω, and it can be seen that the voltage is proportional to the rotational speed. This voltage is a voltage of one coil of a certain phase, and the terminal voltage of the rotating electrical machine varies depending on the connection, but is not proportional to the rotational speed. The output is expressed as the following Equation 3 using the voltage between terminals and the current.

In the case of a motor, what is often used in relation to rotational speed and output is constant output. From Equation 3, if the efficiency and power factor are constant, the current is inversely proportional to the voltage. That is, the current is inversely proportional to the rotation speed.
The main losses in the motor are primary copper loss and iron loss, which are simply expressed as the following Equation 4.

From these results, it can be seen that the voltage is proportional to the rotational speed, the current is inversely proportional to the rotational speed, the primary copper loss is inversely proportional to the square of the rotational speed, and the iron loss is proportional to the square of the rotational speed. A conceptual diagram showing these relationships is shown in FIG. In FIG. 1, V is voltage, I is current, Loss is loss, Φ is magnetic flux, Wc1 is primary copper loss, and Wi is iron loss. Many problems can be seen from FIG.
(1) The maximum rated voltage for use is determined for inverter devices for variable speed operation, etc., and exceeding this will cause failure. For this reason, the upper limit of the speed (number of rotations) of the rotating electrical machine is defined by the maximum voltage.
(2) The maximum temperature rise limit of a rotating electrical machine is limited by coil insulation or the like, and exceeding this will cause insulation failure. For this reason, the upper limit of speed (rotation speed) is prescribed | regulated by the said loss.
(3) If the rotation speed range is to be set wide, a motor drive power source rated for the lowest speed current (maximum current) and the highest speed voltage (maximum voltage) is required. This shows that the power supply is larger than a motor operated at a constant speed.

  The present invention has been made to solve the above-described problems, and by changing the relative angles of a plurality of stators according to the rotational speed during rotation, the voltage between terminals is made to correspond to the relative angle. The purpose is to provide a rotating electric machine that can be adjusted.

In the rotating electrical machine according to the present invention, the stator is divided into a plurality of parts in the axial direction facing the rotor, and each of the divided stators is divided into an inner peripheral side and an outer peripheral side. The stator on the side is movable in the inner peripheral direction with respect to the stator on the outer peripheral side, and further, the inner peripheral side stator is provided with a configuration in which a coil is provided.
During operation of the rotating electrical machine, by changing the relative angle of the plurality of inner peripheral side stators according to the rotation speed, a voltage corresponding to the relative angle is generated between the coil terminals of the plurality of stators. The voltage between the terminals of the rotating electrical machine can be adjusted.

In the rotating electrical machine according to the second aspect of the invention, the stator is divided into a circumferential side and an outer circumferential side, and the inner circumferential side stator is movable in the inner circumferential direction relative to the outer circumferential side stator. The side stator has a configuration in which a coil is provided,
During operation of the rotating electrical machine, the terminal voltage of the rotating electrical machine can be adjusted by moving the inner circumferential side stator in the circumferential direction with respect to the outer circumferential side stator according to the rotational speed.

  Since the rotating electrical machine of the present invention can control the maximum voltage, it can be applied to a wide speed range, can prevent a decrease in power source capacity and failure due to an excessive voltage of an inverter device, etc. There is an excellent effect that it is possible to obtain a rotating electric machine with a small amount.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings.
In FIG. 2, the rotating electrical machine 100 includes a first stator 11 and a second stator 12 that are divided into two in the axial direction so as to face the rotor 3 fixed to the shaft 5. As shown in FIG. 3, each of the first and second stators 11 and 12 is provided with a coil 4d, and a coil end 4a exists outside in the axial direction.
Side views of the stators 11 and 12 are shown in FIGS. In FIG. 3, the stators 11 and 12 are divided into outer peripheral side stators 11a and 12a and inner peripheral side stators 11b and 12b, respectively. The inner peripheral side stators 11b and 12b are circumferential with respect to the outer peripheral side stators 11a and 12a. It is set as the structure provided with the mechanism of the illustration omission which can move to. FIG. 3B shows a diagram in which the inner circumferential side stator 12b moves in the circumferential direction relative to the outer circumferential side stator 12a, relative to FIG.
Further, coils 4d are provided on the inner peripheral side stators 11b and 12b, respectively. In addition, as shown in FIG. 3, the inner peripheral side stators 11b and 12b are composed of a plurality of teeth (teeth) 11e and 12e. It can move in the circumferential direction with respect to the side stators 11a, 12a. The outer peripheral side stators 11a and 12a correspond to yokes, and are provided with convex portions 11c and 12c that are movable and in close contact with the teeth of the inner peripheral side stators 11b and 12b, and concave portions 11d and 12d. Yes.
Since the inner stators 11b and 12b move in the circumferential direction in this way, the first stator 11 and the second stator 12 change the phase angles α and β described later. Can be made. The stator 11 and 12 coils 4d are connected in series or in parallel.
The rotating electrical machine 100 will be described below by taking a motor as an example.
Assuming that the voltage generated in the stator 11 is V1, V1 is expressed as the following Expression 5.

  Similarly, the voltage V2 generated in the stator 12 is as follows.

  From the above results, when the coils of the stator 11 and the stator 12 are connected in series, the voltage generated in the motor is as shown in the following equation (7).

  Here, the maximum voltage is as shown in Equation 8 below.

In general, when two identical stators are connected in series, the maximum voltage is 2 Vm, but in the first embodiment, the value is multiplied by Cos. That is, the maximum voltage can be controlled to be 2 Vm or less by changing the relative position of the stator 11 and the stator 12 in the circumferential direction with respect to the phase angle α of the first stator and the phase angle β of the second stator. it can.
Thus, according to the first embodiment, since the maximum voltage can be adjusted, the limitation on the upper limit of the speed of the rotating electrical machine is relaxed, and the rotating electrical machine can be used in a wide speed range.

  Further, in the conventional technique, for example, when the motor is operated at a variable speed, a power capacity that satisfies the maximum voltage value at the maximum speed and the maximum current value at the minimum speed in the variable speed range has been provided. However, the actual output is much smaller than its power supply capacity. As described above, in the first embodiment, the stator is divided into two parts in the axial direction, and further divided into the outer stator and the inner stator, so that the maximum voltage can be suppressed, which reduces the current. Is also connected. Therefore, the power capacity is reduced.

  Furthermore, since Vm is represented by n · Φm · ω, the voltage rises in proportion to the rotation speed. To suppress this rise in voltage, it is sufficient to reduce Cos. That is, by increasing the phase difference α−β between the phases α and β according to the increase in the rotational speed, it is possible to suppress the voltage increase as the rotational speed increases.

Embodiment 2. FIG.
It is desirable for the motor that the voltage is constant regardless of the rotation speed. In a normal motor, a large current value is required on the low speed side of the operating speed range. However, if the voltage can be kept constant regardless of the rotational speed, the current at low speed can be reduced. In order to keep the voltage constant regardless of the rotational speed, the relative angle θ which is the phase difference between the stators 11 and 12 may be controlled as shown in the following formula 9.

  By controlling the relative angle θ between the stators 11 and 12, the voltage can be kept constant regardless of the rotational speed. Furthermore, when the output is constant, the current can be kept almost constant, and the power source capacity can be reduced. This schematic diagram is shown in FIG.

Embodiment 3 FIG.
When the rotating electrical machine 100 having a plurality of stators is configured, the coil end 4a of the coil 4d provided in each stator is interposed between the stators 11 and 12 and prevents the rotating electrical machine 100 from being downsized. The axial length of the coil end 4a is preferably as short as possible. Therefore, the coil 4d uses the stators 11 and 12 having a toroidal or concentrated winding, thereby shortening the axial length of the coil end 4a and reducing the size of the rotating electrical machine.

Further, as shown in FIG. 5, the stator protrusions 11 e and 12 e that protrude in the axial direction of the rotor 3 are provided on the rotor 3 side of the coil ends 4 a on the opposite sides of the stators 11 and 12. Thus, the magnetic flux 3 can be used effectively. Furthermore, as shown in FIG. 6, the stators 11 and 12 may be configured by a flexible common coil 4 c and the stators 11 and 12 may be provided with a phase difference.
The stators 11 and 12 may have the same axial length or different axial lengths. Although the stator is divided into two parts in the axial direction, it is needless to say that the stator is not limited to two and may be divided into two or more parts.

Embodiment 4 FIG.
In the rotary electric machine having the stator divided into a plurality of parts in the axial direction and the outer and inner peripheral sides of the first embodiment described above, the present invention may be applied to a permanent magnet motor having a permanent magnet in the rotor.
In the case of a normal permanent magnet type motor, an induced voltage is generated only by rotation by the permanent magnet of the rotor without energizing the stator. By applying the stator configuration of the first embodiment, the induced voltage can be reduced. As a result, even if the permanent magnet motor rotates due to some cause when the power is stopped and an induced voltage is generated, the induced voltage is reduced, so that it is possible to easily prevent the failure of the power supply.

Embodiment 5 FIG.
The rotary electric machine according to the first embodiment described above includes the stator divided in the axial direction and the outer and inner peripheral sides. However, the stator of the rotary electric machine according to the fifth embodiment is divided in the axial direction. The outer peripheral side stator 11a is divided into an outer peripheral side and an inner peripheral side, and an inner peripheral side stator 11b is provided. In this case, you may apply to the permanent magnet type motor which provided the permanent magnet in the rotor. The side view of the stator of the fifth embodiment is the same as that shown in FIGS. 3 (a) and 3 (b), but the conceptual diagram corresponding to FIG. 2 described in the first embodiment is the same as this embodiment. In FIG. 5, illustration is omitted.
Here, the reason why the fifth embodiment is adopted will be described.
The maximum voltage Vm is indicated by n · Φm · ω as described above. Here, the magnetic flux amount Φ is inversely proportional to the magnetic resistance Pm. Pm is represented by 1 / μ · l / S. Therefore, the magnetic flux amount Φ is proportional to μ, inversely proportional to the magnetic circuit length l, and proportional to the magnetic circuit cross-sectional area S. As shown in FIG. 3B from the state of FIG. 3A, when the inner peripheral side stator 11b moves in the circumferential direction with respect to the outer peripheral side stator 11a, the μ becomes smaller and Φ decreases. .

As described above, in the fifth embodiment, the stator is not divided in the axial direction, and the inner circumferential side stator 11b is moved in the inner circumferential direction with respect to the outer circumferential side stator 11a according to the rotational speed. Therefore, the increase in the maximum voltage Vm can be suppressed. In the case of a permanent magnet type rotating electrical machine having a permanent magnet in the rotor, an induced voltage is generated only by the rotation of the rotor. By applying the stator configuration of the fifth embodiment, the induced voltage can be reduced. As a result, even if the permanent magnet motor rotates due to some cause when the power is stopped and an induced voltage is generated, the induced voltage is reduced, so that it is possible to easily prevent the failure of the power supply.
Further, even when the power is stopped (rotated) due to some unexpected cause when the power is stopped, an induced voltage is not generated, and damage to related equipment caused by the induced voltage can be prevented.

Embodiment 6 FIG.
When performing variable speed operation of the motor, a variable frequency power supply device such as an inverter is used. In this variable frequency power supply device, optimum operation is performed using the circuit constants of the motor. For example, the phase angle is changed by relatively rotating a plurality of stators as shown in the first embodiment. As a result, the optimum circuit constant of the motor changes. For this reason, optimal operation cannot be achieved if the motor circuit constants are fixed. Therefore, by changing the motor constant according to the relative angles of the plurality of stators, it is possible to perform an optimum operation using the variable frequency power supply device.

Embodiment 7 FIG.
As described in the fourth embodiment, in the case of a permanent magnet type rotating electrical machine having a permanent magnet in the rotor, an induced voltage is generated only by rotating the rotor. Therefore, when the power supply is stopped, voltage is not generated by stopping in a state where the phase angle difference α−β = (90 + 180 × n) degrees of the stators 11 and 12 divided into two. Even when the rotating electrical machine according to the sixth embodiment stopped in such a state is driven (rotated) for some unexpected reason from the outside, an induced voltage is not generated, and the induced voltage is a cause. Damage to the equipment can be prevented.

  As described above, when the first to seventh embodiments of the present invention are applied to a device that requires variable speed operation, such as a generator for an automobile (alternator), a motor for a train, and a spindle motor for a machine tool, There is an effect that efficiency is improved.

It is a conceptual diagram which shows the relationship between the voltage and loss of a rotary electric machine. It is a conceptual diagram which shows the rotary electric machine of Embodiment 1 of this invention. It is a side view which shows the stator of Embodiment 1 and Embodiment 5 of this invention. It is a conceptual diagram which shows the relationship between the voltage and loss of Embodiment 1, 5 of this invention. It is a conceptual diagram which shows the rotary electric machine of Embodiment 3 of this invention. It is a conceptual diagram which shows the other rotary electric machine by Embodiment 3 of this invention.

Explanation of symbols

1 rotor, 4a coil end, 4c coil, 11 first stator,
11a outer stator, 11b inner stator, 12 second stator,
12a Outer peripheral side stator, 12b Inner peripheral side stator.

Claims (11)

A rotating electrical machine including a stator and a rotor, wherein the stator is divided into a plurality of parts in an axial direction facing the rotor, and each of the divided stators is divided into an inner peripheral side and an outer peripheral side. And the inner circumferential side stator is movable in the circumferential direction with respect to the outer circumferential side stator, and further, the inner circumferential side stator has a configuration in which a coil is provided,
During operation of the rotating electrical machine, a voltage corresponding to the relative angle is generated between the coil terminals of the plurality of stators by changing a relative angle of the plurality of inner peripheral side stators according to the rotation speed. When this occurs, the voltage across the terminals of the rotating electrical machine can be adjusted. 2. The rotating electrical machine according to claim 1, wherein when the rotational speed increases, the relative angle also changes so as to increase. 2. The rotation according to claim 1, wherein a voltage between the terminals of the rotating electrical machine is set to a predetermined value by setting a relative angle of the plurality of stators to a predetermined angle determined by the rotation speed. Electric. The rotating electrical machine according to any one of claims 1 to 3, wherein the stator coil is provided with a toroidal winding. The rotating electrical machine according to any one of claims 1 to 3, wherein concentrated winding is applied to the coil of the stator. A rotating electric machine including a stator and a rotor, wherein the stator is divided into an inner peripheral side and an outer peripheral side, and the inner peripheral side stator is provided with a coil and the outer peripheral side stator. A configuration that is movable in a circumferential direction with respect to the outer peripheral stator in accordance with the rotational speed of the rotating electrical machine during operation, A rotating electrical machine characterized in that a voltage between terminals of the rotating electrical machine can be adjusted. The rotating electrical machine according to any one of claims 1 to 5, wherein the rotating electrical machine has a rotor of a permanent magnet type. The rotating electrical machine according to claim 6, wherein the rotating electrical machine has a permanent magnet type rotor. The rotary electric machine is provided with a drive inverter device, and a circuit constant of the drive inverter device changes according to a rotation speed of the rotary electric machine. The rotating electrical machine according to any one of claims. The rotating electrical machine is provided with a driving inverter device, and a circuit constant of the driving inverter device changes according to a rotation speed of the rotating electrical machine, and the rotation of the driving inverter device is stopped when the driving inverter device is stopped. The rotating electrical machine according to claim 7, wherein the rotating electrical machine is stopped so that the relative angle of the stator becomes a predetermined angle so that no voltage is generated in the electrical machine. The rotating electrical machine is provided with a driving inverter device, and a circuit constant of the driving inverter device changes according to a rotation speed of the rotating electrical machine, and the rotation of the driving inverter device is stopped when the driving inverter device is stopped. The rotating electrical machine according to claim 8, wherein the rotating electrical machine is stopped so that a relative angle between the inner peripheral side stator and the outer peripheral side stator becomes a predetermined angle so that no voltage is generated in the electrical machine.

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