JPH11252881A - Synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress properly the terminal voltage of an armature winding and improve the power factor in the opening of the armature winding in a salient pole-type synchronous motor which has no field winding. SOLUTION: In a rotating magnetic field salient pole-type synchronous motor having no field winding, salient magnetic poles 31 formed in a rotor 3 are constituted of a permanent magnet section 311 and magnetic material sections 312, 313 which are arranged serially in the rotor axis direction with the permanent magnet section 311 interposed between the magnetic material sections 312 and 313 and a fixed component of armature winding interlinkage magnetic flux is generated by the permanent magnet 311 and a variable portion of it is generated by an excitation current component of armature current in the magnetic material sections 312, 313. By making variable the armature induced voltage corresponding to the magnetic material sections 312, 313 through means of controlling the excitation current component in the armature current, the motor can be operated so that the entire armature induced voltage as a whole, including the induced voltage corresponding to the permanent magnet section 311, can be set to a given value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a salient pole type synchronous motor having no field winding for improving a power factor characteristic and suppressing an excessive induced voltage when an armature winding is opened.

[0002]

2. Description of the Related Art As a conventional synchronous motor of this type, there is known a rotating field salient-pole synchronous motor whose characteristic shapes are illustrated in both cross-sectional views of FIGS. Both of the cross-sectional views show cross-sectional patterns in a direction orthogonal to the motor shaft. First, FIG. 3 is a sectional view of a permanent magnet type synchronous motor, wherein 1 is an armature, 5 is a rotor, 7 is a rotor shaft, 11 is an armature winding to which a power supply AC voltage is applied, and 51 is a permanent magnet. The magnetic poles are arranged such that the polarity of the surface facing the armature winding 11 is alternately N-pole and S-pole.

Next, FIG. 4 is a sectional view of a reluctance motor, wherein 1 is an armature, 6 is a rotor made of a magnetic material having salient pole-shaped magnetic poles 61, and 7 is a rotor shaft.

[0004]

In a normal operation of a permanent magnet type synchronous motor, a required magnetic flux is generally supplied by a permanent magnet forming its magnetic pole, so that an excitation in an armature current supplied from an AC power source is generally performed. The current component is extremely small, and both the power factor and the efficiency are good. However,
The internal induced voltage in the armature of a permanent magnet type synchronous motor has the property of increasing with an increase in the number of revolutions of the motor. During high-speed operation, a large amount of delayed reactive current corresponds to the field weakening state accompanying the increase in the internal induced voltage. If the internal induced voltage becomes higher than the power supply voltage due to the high-speed operation, it is not easy to turn on the synchronous motor again after the power supply is disconnected.

On the other hand, in a reluctance motor, the required magnetic flux is defined by the exciting current component in the armature current, and the internal induced voltage increases as the motor speed increases and depends on the exciting current component. The induced voltage inside the armature can be adjusted by controlling the exciting current component in the armature current. Note that the armature current is always in a low power factor state with a delay.

[0006] In view of the above, the present invention optimizes the absolute value of the exciting current component in the armature current in the entire operation range from the low speed range to the high speed range, that is, the absolute value of the armature current itself and the power factor of the power factor. A salient pole type synchronous motor that does not have a rotating field type or rotating armature type field winding that achieves optimization and moderate suppression of the same winding terminal voltage when the armature winding is opened in a predetermined operation range. It is intended to provide an electric motor.

[0007]

To achieve the above object, the present invention provides a synchronous motor of the present invention. 1) The invention of claim 1 is directed to a synchronous motor having a salient pole structure without a field winding. The magnetic pole is formed by arranging a permanent magnet and a magnetic body in series in the axial direction of the motor.

[0008] According to a second aspect of the present invention, in the synchronous motor of the first aspect, the magnetic poles are divided into permanent magnets and magnetic bodies, each of which is divided into an appropriate number, alternately arranged in an appropriate order in the axial direction of the motor. Shall be formed. 3) The invention according to claim 3 is a synchronous motor having a salient pole structure having no field winding, wherein the magnetic pole is formed of a pair of NS polarity magnetic poles formed of permanent magnets and arranged adjacent to each other. A pair of magnetic poles made of a magnetic material and arranged so as to be adjacent to each other is formed so as to be axially symmetric with respect to the motor shaft.

According to a fourth aspect of the present invention, in the synchronous motor according to any one of the first to third aspects, the synchronous motor includes an armature winding and respective magnetic poles each having a stator. It is assumed to be a rotating field type provided on the rotor. 5) The invention according to claim 5 is the synchronous motor according to any one of claims 1 to 3, wherein the synchronous motor includes an armature winding and respective magnetic poles, a rotor and a stator, respectively. In the form of a rotating armature.

As described above, the present invention provides a synchronous motor equivalent to a state in which the rotor shafts of both a permanent magnet type synchronous motor having the same number of poles and a reluctance motor are directly connected, and the respective armature phase windings are connected in series. To obtain a salient pole type synchronous motor having no rotating field type or rotating armature type field winding having an intermediate characteristic between the two motors.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 by taking a rotating field salient pole type synchronous motor as an example. Here, FIG. 1 shows a first embodiment of the present invention according to claims 1 and 2, and FIG. 2 shows a second embodiment of the present invention according to claim 3.

First, referring to FIG. 1, FIG. 1A is a side view of a main body of a rotating field salient pole synchronous motor, and FIG. Is an armature,
3 is a rotor, 7 is a rotor shaft, 11 is an armature winding, 31
Are magnetic poles of a salient pole structure having no field winding formed on the rotor 3. FIG. 3C is a side view of the rotor 3, in which the salient pole structure of the magnetic pole 31 is replaced with a permanent magnet portion 311 formed of a permanent magnet and magnetic material portions 312 and 3 formed of a magnetic material.
13 and the permanent magnet part 311 is divided into three parts.
And 313 are arranged in series in the direction of the rotor axis to form magnetic poles.

Here, with respect to the armature winding interlinkage magnetic flux that defines the armature induced voltage, the fixed portion is controlled by the permanent magnet portion 311 of the magnetic pole and the variable portion is controlled by the magnetic portion 3.
12 and 313;
The formation of the interlinkage magnetic flux in steps 313 and 313 is performed by the exciting current component in the armature current supplied from the AC power supply.

Therefore, by making the armature induced voltage corresponding to the magnetic portions 312 and 313 variable through control of the exciting current component in the armature current, the induced voltage corresponding to the permanent magnet portion 311 is included. The motor can be operated so that the armature induced voltage has a predetermined value as a whole. FIG.
(C) is an example in which the magnetic pole is divided into a permanent magnet portion and a magnetic material portion, but in general, the number of divisions of the permanent magnet portion and the magnetic material portion when dividing the magnetic pole, the length of each portion, and the alternation of each portion. Are appropriately selected according to required motor characteristics such as the armature induced voltage and the power factor of the armature current as described above.

Referring now to FIG. 2, FIG. 2A is a side view of the main body of the rotating field salient pole synchronous motor, and FIG. 2B is a sectional view of the motor in a direction orthogonal to the rotor axis. 1 is an armature,
4 is a rotor, 7 is a rotor shaft, 12 is an armature winding, 41
And 42 are magnetic poles of a salient pole structure formed on the rotor 4, and 41a and 41b are magnetic poles formed of permanent magnets and forming a pair of N and S poles arranged adjacent to each other, Reference numerals 42a and 42b denote pairs of magnetic poles formed of a magnetic material and arranged adjacent to each other.

In a synchronous motor as shown in FIG. 2, the number of pairs of all magnetic poles of the rotor is generally k (k is an even number of 4 or more), and i pairs (i is an even number of 2 or more, i < k) is a permanent magnet, and the remaining j pairs (j = ki: even number) are magnetic materials, each of which forms a magnetic pole having a salient pole structure. Are arranged point-symmetrically in the direction of rotation to balance the attractive forces between the magnetic poles. Accordingly, FIG. 2B shows that k = 4, i = 2,
This is an example when j = 2.

FIG. 2C illustrates a state in which the three-phase winding composed of the first phase, the second phase, and the third phase is star-connected to the armature winding 12. The structure of one phase winding of the three-phase winding is shown in FIG.
And the winding portions 121 and 122 corresponding to the permanent magnet portion 41 and the magnetic body portion 42 in the magnetic poles of the rotor 4 correspond to the magnetic pole movement accompanying the rotation of the rotor 4, respectively. However, the armature induced voltages generated in the two winding portions are added in series.

The above-described windings of each phase can be connected in the same manner as in the case of a conventional AC motor, such as three-phase, multi-phase, star connection, and terta connection. Here, the fixed part of the armature winding interlinkage magnetic flux that defines the armature induced voltage is formed by the permanent magnet part 41 of the magnetic pole, and the variable part thereof is formed by the magnetic body part 42, and corresponds to the two magnetic pole parts. The armature induced voltages are added in series in the armature winding 12. Accordingly, the armature induced voltage corresponding to the magnetic body portion 42 is made variable by controlling the exciting current component in the armature current, and the motor can be operated so that the armature induced voltage has a predetermined value as a whole.

Although the embodiment of the rotary armature type synchronous motor is not shown here, its electric characteristics are the same as those of the above-mentioned rotary field type synchronous motor.

[0020]

According to the present invention, in a synchronous motor of a rotating field salient pole type or a rotating armature salient pole type having no field winding, the magnetic poles are made of a permanent magnet and a magnetic material. Are arranged in series in the axial direction of the motor, and in the synchronous motor according to claim 1, the permanent magnet and the magnetic body are divided into appropriate numbers, respectively. The magnetic poles are formed by alternately arranging the magnetic poles in an appropriate order in the axial direction, and the magnetic poles are formed by a permanent magnet and a pair of adjacently arranged NS magnetic poles. By forming a pair of magnetic poles formed of a body and arranged so as to be adjacent to each other so as to be axially symmetric with respect to the motor axis, an electric current intermediate between the permanent magnet type synchronous motor and the reluctance motor can be obtained. With characteristics, low-speed rotation In a predetermined operating range from high to high speed rotation, the absolute value of the exciting current component in the armature current is optimized to maintain a relatively good power factor, and when the armature winding is opened in the predetermined operating range. It is possible to obtain a salient pole synchronous motor having no field winding, which makes it possible to moderately suppress the winding terminal voltage and to safely and easily turn on the power after opening the power supply during high-speed operation. An electric motor suitable for a voltage of an AC power supply or a synchronous motor by forming the synchronous motor as a rotating field type as described in claim 4 or as a rotating armature type as described in claim 5. The format can be selected.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention; (a) is a side view of a rotating field salient pole synchronous motor; C) Side view of the rotor of the electric motor

FIGS. 2A and 2B show a second embodiment of the present invention. FIG. 2A is a side view of a rotating field salient-pole synchronous motor, and FIG. C) Connection diagram of armature winding of the motor

FIG. 3 is a sectional view of a permanent magnet synchronous motor showing a first embodiment of the prior art.

FIG. 4 is a cross-sectional view of a reluctance motor showing a second embodiment of the prior art.

[Explanation of symbols]

 Reference Signs List 1 armature 3-6 rotor 11, 12 armature winding 31 magnetic pole 41 magnetic pole (permanent magnets: 41a, 41b) 42 magnetic pole (magnetic bodies: 42a, 42b) 121 permanent magnet magnetic pole corresponding portion 122 of armature winding 12 Magnetic pole corresponding part of armature winding 12 311 Permanent magnet part of magnetic pole 31 312 Magnetic part of magnetic pole 31 313 Magnetic part of magnetic pole 31

Claims (5)

[Claims] 1. A synchronous motor having salient-pole structure magnetic poles without field windings, wherein the magnetic poles are formed by arranging permanent magnets and magnetic materials in series in the motor axial direction. Characteristic synchronous motor. 2. The synchronous motor according to claim 1, wherein said magnetic poles are formed by alternately arranging permanent magnets and magnetic bodies divided into an appropriate number in an appropriate order in an axial direction of the motor. Synchronous motor characterized by the following: 3. A synchronous motor having salient pole structure magnetic poles without field windings, wherein the magnetic poles are formed of a pair of NS-polarity magnetic poles formed of permanent magnets and arranged adjacent to each other, and a magnetic body. And a pair of magnetic poles arranged so as to be adjacent to each other,
A synchronous motor characterized by being formed so as to be axially symmetric with respect to a motor shaft. 4. The synchronous motor according to claim 1, wherein said synchronous motor includes an armature winding and respective magnetic poles provided on a stator and a rotor, respectively. Synchronous motor characterized by being a field type. 5. The synchronous motor according to claim 1, wherein said synchronous motor includes an armature winding and respective magnetic poles provided on a rotor and a stator, respectively. Synchronous motor characterized by being an armature type.