JPH03261355A - Synchronous induction motor of two or more stators - Google Patents

Abstract

PURPOSE:To increase both starting torque and synchronizing torque by changing the phase difference angle of induced voltage in a rotor conductor at the time of starting and synchronized rotation. CONSTITUTION:A motor is started by closing a power supply in a condition that stator windings 21, 22 are connected so as to obtain a zero phase difference angle of induced voltage in rotor conductors 31, 32 at the time of starting. Here starting torque is increased because no flow of current is generated in a diode 34 by allowing a current in the rotor conductor to flow so as to recirculate in the rotor conductor 32 from the rotor conductor 31. When a rotational speed approaches the synchronous speed, phase difference between two rotational magnetic fields, generated by the rotor conductors 31, 32, is set at 180 deg.. In this way, the current is recirculated through the diode 34 by stopping the recirculation to the rotor conductor 32 from the rotor conductor 31. Thus by forming a magnetic pole in a rotor core, it is rotated while being pulled by a rotational magnetic field generated by the stator windings 21, 22.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a synchronous motor.

[Conventional technology]

Generally, a synchronous motor requires a starter that accelerates the rotor to the rotation speed of the rotating magnetic field generated by the stator winding, that is, close to the synchronous speed, and DC excitation of the rotor winding.

The induction synchronous motor was devised to omit this starter and give the synchronous motor itself its own starting torque.This motor short-circuits the rotor windings at startup and starts the motor as an induction motor. Although not required, brushes are required for DC excitation of the rotor windings required for synchronous operation.

That is, when the rotational speed of the rotor approaches the synchronous speed, the short circuit in the rotor winding is opened, and a DC current is passed from an external DC power source to the rotor winding through the brushes to create magnetic poles in the rotor. , these magnetic poles are pulled by the rotating magnetic field created by the stator windings, causing the rotor to rotate at a synchronous speed. This brush requires maintenance and inspection, which increases maintenance costs, and there is a desire to develop a synchronous motor with a brushless structure.

Conventionally, synchronous motors with this brushless structure have either permanent magnet type or reluctance type, and have low torque.
Due to problems such as demagnetization and low power factor, it is limited to small capacity devices. Furthermore, Ransol-type and inductor-type synchronous motors have the disadvantage of having complicated magnetic path configurations and being large.

Also, the method using an AC exciter and a rotating rectifier is similar. In addition, brushless self-excited three-phase synchronous motors that connect diodes to the rotor windings and utilize the harmonic magnetic field generated by the square wave voltage of the inverter have the disadvantage that sufficient output cannot be obtained due to insufficient field magnetomotive force of the rotor. There is. Furthermore, by inserting a diode into one phase of the three-phase stator winding, a static magnetic field is superimposed on the positive phase rotating magnetic field generated by the stator, and the alternating current voltage due to the static magnetic field is applied to the rotor winding rotating at a synchronous speed. There is a brushless self-excited three-phase synchronous motor that excites the rotor winding with DC current by inducing this and rectifying it with a diode, and generates synchronous torque by applying a positive phase rotating magnetic field. This is because the induction motor cannot be started, so the starting torque is small due to the eddy current in the rotor core.

[Problem to be solved by the invention]

Therefore, the technical object is to provide a synchronous motor that has a large starting torque and a large synchronous torque, does not require brushes, is easy to maintain and inspect, has a simple structure, and does not require a dedicated starter.

[Means to solve the problem]

In order to solve the above problem, a plurality of rotor cores are provided on the same rotating shaft at arbitrary intervals, and a plurality of conductors are provided that communicate with the plurality of rotor cores, and both ends of the conductors are short-circuited. a rotor formed into a squirrel-cage conductor; a plurality of stators disposed around each of the rotor cores facing each other; and a portion of the conductor communicating with the plurality of rotor cores that does not face the stator. A diode connecting conductors located at an electrical angle of 1800 degrees with respect to each other, a rotating magnetic field generated around a rotor core to which a specific stator faces the other stator, and a rotating magnetic field generated around the rotor core, which is opposed to a specific stator among the plurality of stators. A voltage phase shift device that creates a phase difference between the rotating magnetic field generated around the rotor core facing the rotor core and a DC excitation circuit provided in the plurality of stators, or on the same rotating shaft. A rotor having a plurality of rotor cores arranged at arbitrary intervals, a plurality of conductors communicating with the plurality of rotor cores, and both ends of which are short-circuited to form squirrel cage conductors; A plurality of stators are provided around the rotor core, each facing the rotor core, and a rotating magnetic field generated around the rotor core where a specific stator among the plurality of stators faces the stator, and other stators. and a rotating magnetic field generated around a rotor core facing the voltage phase shifter; a rotating armature directly connected to the rotating shaft and having a rectifying circuit; In addition to providing circumferentially facing stators for direct current excitation, the direct current outputs of the rectifying circuit of the rotating armature are connected to each other using portions of conductors that communicate with the plurality of rotor cores that do not face the stator. A means for solving the above problem is achieved by connecting conductors located at 180 degrees in electrical angle in parallel via a diode.

[For production]

The details of the operation of a voltage phase shifter for a multi-stator induction motor have been described by the present applicant in Japanese Patent Application No. 128314/1983.

According to the present invention, first, a plurality of rotor cores are provided on the same rotating shaft, and a plurality of conductors are provided in communication with the plurality of rotor cores, and both ends of the conductors are short-circuited to form a squirrel cage conductor. In a device consisting of multiple stators equipped with stator coils, stator windings, and DC excitation circuits, the voltage induced in the multiple rotor conductors by the rotating magnetic field created by the multiple stator windings during startup. so that they are in phase, that is, so that a circulating current flows between the rotor conductors, so that no current flows through the diodes connected between the rotor conductors located at 180 degrees electrical angle from each other. , the voltage phase shift device is activated to start the motor as a general induction motor. When the rotational speed of the rotor increases after startup and approaches the rotational speed of the rotating magnetic field, that is, the synchronous speed, the voltage induced in the rotor conductor by the rotating magnetic field becomes smaller. Up to this point, the motor is operating as an induction motor, but when the slip S approaches 5=11.05, it enters synchronous operation. This is done as follows.

First, there is a difference of 180 degrees between the rotating magnetic field generated around the rotor core facing a specific stator among the plurality of stators and the rotating magnetic field generated around the rotor core facing the other stators. The voltage phase shifter is activated to create a degree phase difference.

By doing this, the current that had previously flowed back and forth between the rotor conductors will no longer flow, and the current will now flow through the diodes that connect the rotor conductors that are located at 180 degrees electrical angle from each other.

The current flowing in the rotor conductor due to this rotating magnetic field stops flowing because the slip becomes zero when the rotor reaches synchronous speed, but if the DC excitation circuit installed in the stator is activated at the same time as the voltage phase shift device described above, This DC excitation circuit generates a static magnetic field, and the rotor conductors interlink with this static magnetic field to induce an AC voltage. This AC voltage increases as the rotational speed of the rotor increases.

Since the phase of this AC voltage is interlocked with the voltage phase shifter, this AC voltage is applied to the diode connected between the conductors of the rotor conductor, and acts so that the rectified current flows through the rotor conductor. The rotor core forms magnetic poles and is pulled by the rotating magnetic field created by the stator windings, causing the rotor to rotate at a synchronous speed.

Considering synchronous torque here, the phase of the rotating magnetic field generated by a specific stator among multiple stators is shifted by 180 degrees from that of the rotating magnetic field generated by other stators. The direction of the diode-rectified current flowing through the rotor conductor of a rotor facing a particular stator due to the static magnetic field is also in the opposite direction to that of other rotor conductors, so the synchronous torque is the same for all rotors. , and all the synchronous torques are added together. Although the induction synchronous motor of the present invention has a plurality of stators, its total capacity is equivalent to that of a conventional induction synchronous motor with brushes.

As described above, the multiple stator induction synchronous motor of the present invention is
When starting, the starting torque is large because the starting principle is based on the principle of a conventional induction motor, and therefore no other special starter is required. Furthermore, at synchronous speed, the rotor conductor acts as a DC excitation winding, so the synchronous torque is large, making it possible to provide a synchronous motor that does not require maintenance such as brushes.

In addition, instead of the DC excitation circuit, a rotating armature having a rectifier circuit on the rotating shaft and a stator for DC excitation disposed around it opposite to it are provided, and the DC output of the rectifier circuit is connected to a diode in the rotor conductor. It is also possible to connect the rotor conductors in parallel through the rotor and excite the rotor conductors with direct current [thus, synchronous operation is possible.

By the way, the above-mentioned DC excitation circuit utilizes one phase of a plurality of stator windings, and a circuit in which a thyristor and a diode are connected in parallel with opposite polarity is inserted into one phase of the stator winding, and the thyristor is ignited. It is also possible to create a static magnetic field by changing the angle and passing a direct current through the winding.

The voltage phase shift device was developed by the applicant in Japanese Patent Application No. 1986-1.
No. 28314 describes two methods: one in which the position of the stator is changed by mechanically rotating it around a rotating shaft, and the other in which the connection of the stator windings is changed by a switch.

With the above configuration, it is possible to provide a synchronous motor that has a large starting torque, a large synchronous torque, does not require brushes, is easy to maintain and inspect, has a simple structure, and does not require a dedicated starter. It became.

By the way, the power source for exciting the stator winding can be a commercial frequency AC power source or a variable frequency power source using an inverter. Moreover, it can be used in both single phase and polyphase. By using the variable frequency power supply mentioned above, it becomes possible to easily change the synchronous speed, and even in that case, it can be started with the starting torque of a normal induction motor, greatly expanding the field of use and making it possible to provide inexpensive synchronous motors. became.

〔Example〕

Although the present invention will be described in detail mainly with a two-stator induction motor as its main configuration, it goes without saying that the number of stators is not limited to this. Furthermore, the stator windings may be connected in parallel, in series, in star connection, or in delta connection. Furthermore, it may be 2-phase, 3-phase, or polyphase. The same applies to the rotor conductor. The applicant has already filed a patent application in 1983-1283.
No. 14 provides a detailed explanation of the structure and operation of an induction motor consisting of a plurality of stators, which is a part of the structure of the present invention. In other words, due to the voltage phase shift device, a rotating magnetic field is generated around the rotor that a specific stator faces from among multiple stators, and a rotating magnetic field is generated around the rotor that faces the other stators. For example, if the phase difference between the It explains in detail how the fluid flows between the rotor cores and through the connecting material that connects the rotor conductors.

Further, regarding the configuration of the voltage phase shift device, one that rotates the stator and one that switches the wiring connection of the stator winding are shown, but in the present invention, in particular, the configuration of the voltage phase shift device is If a voltage phase shifter is configured by performing the above steps, the electrical angle can be switched from 0° to 1800° instantaneously, and therefore it is easy to achieve synchronous speed. In addition, by installing and communicating a sensor that detects the rotation speed, a DC excitation circuit, and a control device for the voltage phase shifter, it is possible to automate the pull-in to the synchronous speed, and even in the event of a tax adjustment, the rotation speed can be detected. It is possible to immediately switch from synchronous operation to induction motor operation based on a sensor signal, and unlike general synchronous motors, there is no sudden stop due to tax adjustment, making it easy to prevent accidents.

A first embodiment of the present invention will be explained with reference to FIGS. 1 to 3. First, reference numeral 20 indicates the stator side of the two-stator induction motor. Further, the reference numeral 30 similarly indicates the rotor side.

The stator side 20 has two star-connected stator windings 21.
．． 22 are three-phase AC power supplies R and S in parallel.

Connected to T. Furthermore, on the stator side 20, in addition to the stator windings 21 and 22, there is a DC excitation winding 40 of the DC excitation circuit.
is the provision. On the other hand, a plurality of conductors 31 and 32 are provided which communicate with the two rotor cores provided on the same rotating shaft 10 on the rotor side 30, and short-circuit rings 33 are provided at both ends of the conductors 31 and 32 to form squirrel cage conductors. The portion 37 of the conductor that does not face the stator and communicates with the rotor core of the conductor is 180° electrically
The conductors located at are connected via a diode 34. This is shown in FIG. Alternatively, as shown in FIG. 3, conductors located at 1800 electrical angles may be connected via a diode 34 and a connecting ring 36, as shown in FIG. Incidentally, although FIGS. 2 and 3 show the case of two poles, it goes without saying that the present invention is not limited to this.

Here, it is assumed that the voltage induced in the rotor conductor 31 facing the stator winding 21 is El, and the voltage induced in the rotor conductor 32 facing the stator winding 22 is E1ε. Here θ
is the voltage phase difference angle.

The effect of the above configuration will be explained. First, at startup, the power is turned on with the stator windings 21 and 22 connected so that the phase difference angle θ of the induced voltage of the rotor conductors 31 and 32 is 08. In this way, the stator winding 21
．． Three-phase currents flow from the power supply through the rotor 22 to generate rotating magnetic fields of the same phase, and voltages are induced in the rotor conductors 31 and 32. Since the phase difference angle of the induced voltage in this case is θ=θ°,
The current flowing through the rotor conductor flows from the rotor conductor 31 to the rotor conductor 32 in a circular manner, and no current flows through the diode 34 connected between the rotor conductors. Therefore, the starting torque is started with the same characteristics as a conventional induction motor as shown in FIG. 7, the starting torque is large, and a special separate starter is not required. After startup, the rotation speed of the rotor increases and approaches the rotation speed of the rotating □ magnetic field, that is, the synchronous speed,
Since the shift S becomes smaller, the induced voltage E1 in the rotor conductor due to the rotating magnetic field becomes smaller. Up to this point, the motor has been operating as an induction motor, but when it approaches S=0.05, it enters synchronous operation. This is done as follows.

Firstly, the two stator windings 21 and 22 are connected by a voltage phase shifter.
For example, by changing the position of the stator winding 22 by rotating the core of the stator around the rotation axis, the phase difference angle between the two rotating magnetic fields created by the two stator windings 21 and 22 can be changed. Set θ to θ=180°. In this way, the phase difference angle θ between the induced voltages of the two rotor conductors 31 and 32 becomes θ=180°, and the rotor conductors 31 and 32
The current due to the rotating magnetic field that was flowing back to the rotor conductor 32 no longer flows back to the rotor conductor 32, and begins to flow through the diode 34 connected between the rotor conductors. In addition, the DC excitation winding 40 provided on the stator is activated together with the voltage phase shifter described above. In other words, when a static magnetic field is created by passing a DC current through the DC excitation winding 40, the rotor conductors 31 and 32 become S.
Even if it becomes 0, it interlinks with these static magnetic fields and induces an alternating current voltage. The alternating current voltage due to this static magnetic field increases as the rotation speed of the rotor increases. The phase of the AC voltage due to this stationary magnetic field is determined by the DC excitation winding 40 interlocking with the voltage phase shifter, so that the two rotor conductors 31 and 32
The phase difference angle θ of the AC voltage due to the static magnetic field induced in is θ=
180', a current rectified by these alternating voltages through the diode 34 connected between the conductors of the rotor conductors flows through the rotor conductors 31.32, the rotor core forms magnetic poles, and the stator windings 21.32. The rotor is pulled by the rotating magnetic field created by 22 and rotates at a synchronous speed. The synchronous torque at this time is as shown in FIG. Since this synchronous torque is proportional to the strength of the static magnetic field, it is possible to obtain a large synchronous torque. Further considering this synchronous torque here, during synchronous operation, the phase of the rotating magnetic field created by the stator winding 22 is shifted by 180' with respect to that of the stator winding 21 by the voltage phase shifter, and furthermore, The alternating current voltage induced in the rotor conductor 32 by the static magnetic field is also phase shifted by 180° with respect to that of the rotor conductor 31,
Since the rectified current flows in a direction that does not circulate through the rotor conductors, i.e. from each rotor conductor through the diode 34, the synchronous torques will be in the same direction in the two rotors, and the synchronous torques will be additive, thus achieving the advantage of the present invention. Although the induction synchronous motor has two stators, its total capacity is equivalent to a conventional induction synchronous motor with brushes.

As described above, the multiple stator induction synchronous motor of the present invention is
When starting, the starting torque is large because the starting principle is based on the principle of a conventional induction motor, and therefore no other special starter is required.

Furthermore, at synchronous speed, the rotor conductor acts as a DC excitation winding, that is, a field winding, so it has become possible to provide a synchronous motor that has a large synchronous torque and does not require maintenance such as brushes.

Now, in this example, as a voltage phase shifter that creates a phase difference in the induced voltage of the rotor conductor, a method is described in which the core of one stator is rotated around the rotation axis, but the wiring connection of the stator winding is changed. In other words, by swapping and connecting both terminals of the stator winding, the phase difference angle θ can be changed electrically from θ=0° to θ=1.
It is also possible to switch to 80°.

Further, in this embodiment, a method using a commercial power source as a power source has been described, but it is also possible to operate at any synchronous speed by using a variable frequency power source such as an inverter.

Next, a second embodiment will be explained with reference to FIGS. 4 and 5.

This embodiment differs from the first embodiment in the DC excitation method of the rotor conductors required during synchronous operation. That is, a rotating armature type AC generator 50 is directly connected to the rotating shaft 10, the output voltage of the armature winding 56 is rectified by a rectifying circuit 55, and its DC output terminal is connected to the plurality of rotor cores. At a portion 37 of the communicating shear conductor that does not face the stator, conductors located at 1800 degrees electrical angle from each other are connected in parallel via a diode 34.

This will be explained in more detail with reference to FIG. That is, the positive terminal of the DC main terminal of the rectifier circuit 55 is connected to the rotor conductor via the diode 34, and the electrical angle of 1
The rotor conductor located at the 80 degree position is connected to the negative electrode of the DC output terminal of the rectifier circuit 55 via the diode 34. The same goes for the other conductors, and they are configured so that the direct current flowing from the rectifier circuit 55 forms magnetic poles on the rotor equal to the number of poles on the stator. Although a two-pole configuration is shown as in the first embodiment, the present invention is not limited to this.

Furthermore, during synchronous operation, the stator side 51 of the rotating armature type AC generator 50 is excited by passing a DC current from a DC power supply 54 through the DC excitation winding 53 to induce an AC voltage in the rotating armature 56. This AC voltage is rectified by the rectifier circuit 55, and this rectified current is shunted to the rotor conductor 31.32 via the diode 34, thereby DC exciting the rotor conductor 31.32, and the stator winding 21 .22 generates a rotating magnetic field for synchronous operation.

In this method, the rectified current flowing through the rotor conductors 31 and 32 can be full-wave rectified by the rectifier circuit 55.
There is an advantage that the synchronous torque is larger than that of the half-wave rectification of the first embodiment.

Next, another example of direct current excitation in the first and second examples is shown in FIG.

This embodiment differs from the first and second embodiments in that the DC excitation winding 40 shown in FIGS. 1 and 4 is omitted and a portion of the stator winding is used. That is, the sixth
As shown in the figure, a circuit in which a thyristor 71 and a diode 72 are connected in parallel with opposite polarities is inserted into one phase of the stator windings 21 and 22. This operates when creating the static magnetic field described in the first and second embodiments, which is necessary during synchronous operation. In other words, the firing angle of the thyristor 71 is set to 00.
thicker (then, a current containing a DC component flows through the stator windings 21 and 22 due to the diode 72, making it possible to create a stationary magnetic field. In this way, it is possible to create a static magnetic field with a DC component separate from the stator windings). This has the advantage of simplifying the structure since there is no need to provide an excitation winding.

However, in this case, the rotating magnetic field created by the stator windings 21 and 22 is distorted, so a synchronous torque is generated by the positive phase rotating magnetic field based on the symmetrical coordinate method. Other operations are similar to those in the first and second embodiments.

With the above configuration, the multiple stator induction synchronous motor of the present invention starts as an induction motor at startup, and when it approaches the synchronous speed, the slip is attracted to the synchronous speed from around S = 0.05, and the synchronous motor It rotates as follows.

〔effect〕

From the above configuration, the multiple stator induction synchronous motor of the present invention has the following features:
At startup, it has the same torque characteristics as a conventional induction motor,
For example, the Suberi S shifts to a synchronous speed from around S-005 and operates with the torque characteristics of a synchronous motor. This multi-stator induction synchronous motor does not require a starter or brushes, which not only simplifies its structure and configuration.
Since it can be started with the same torque characteristics as conventional induction motors, it is possible to start and operate synchronously even under heavy loads.

By the way, since the multiple stator induction synchronous motor of the present invention has the torque characteristics of both an induction motor and a synchronous motor, it can be used with the torque characteristics of either motor. This means that even if the motor loses synchronization for some reason while operating at synchronous speed, it is possible to switch from the synchronous motor torque characteristic to the induction motor torque characteristic, so the motor will not suddenly stop like a general synchronous motor. There is no.

As described above, since there are no brushes and no complicated configuration is required, maintenance and inspection are easy, and it has become possible to provide a synchronous motor with a large starting torque and a large synchronous torque.

[Brief explanation of drawings]

Figure 1 is a simplified configuration diagram of the stator winding side and rotor conductor side of the first embodiment, Figure 2 is a simplified configuration diagram of the rotor conductors of the first embodiment connected by diodes, Fig. 3 is another simple configuration diagram in which the rotor conductors of the first embodiment are connected through diodes, and Fig. 4 is a simple front cross-sectional view of the stator winding side and the rotor conductor side of the second embodiment. , FIG. 5 is a simple configuration diagram in which the rotor conductor and rectifier circuit of the second embodiment are connected via diodes, and FIG. 6 is a diagram showing the stator side DC excitation shown in the first and second embodiments. Another embodiment of the circuit, FIG. 7, is a diagram showing an example of the torque characteristics of the synchronous motor of the present invention. DESCRIPTION OF SYMBOLS 10... Rotating shaft, 20... Stator side, 21... Stator winding, 22... Stator winding, 30... Rotor side, 31... Rotor conductor, 32 ...Rotor conductor, 33
... Short circuit ring, 34... Diode, 35... Rotor side, 36... Connection ring, 37... Rotor conductor portion not facing the stator, 40... DC excitation winding, 50...
- Rotating armature type alternator, 51... Stator side of the alternator, 52... Rotating armature side of the alternator, 53.
... DC excitation winding, 54 ... DC power supply, 55 ... Rectifier circuit, 56 ... Rotating armature, 70 ... Stator side,
71...thyristor, 72...diode.

Claims (3)

[Claims] (1) It has a plurality of rotor cores arranged at arbitrary intervals on the same rotating shaft, a plurality of conductors are provided that communicate with the plurality of rotor cores, and both ends are short-circuited to form a squirrel cage. A rotor that is a conductor, a plurality of stators disposed around each of the rotor cores facing each other, and a portion of the conductor that communicates with the plurality of rotor cores that does not face the stator are electrically connected to each other. A diode connecting conductors located at 180 degrees at a corner, a rotating magnetic field generated around a rotor core with which a specific stator of the plurality of stators faces, and another stator with which it faces. and a DC excitation circuit provided in the plurality of stators. Electric motor. (2) It has a plurality of rotor cores arranged at arbitrary intervals on the same rotating shaft, a plurality of conductors are provided that communicate with the plurality of rotor cores, and both ends are short-circuited to form a squirrel cage shape. A rotor as a conductor, a plurality of stators disposed around each of the rotor cores facing each other, and a specific stator among the plurality of stators surrounding the rotor core facing the rotor core. A rotating electric machine having a voltage phase shift device that creates a phase difference between a generated rotating magnetic field and a rotating magnetic field generated around a rotor core opposed by another stator, and a rectifier circuit directly connected to the rotating shaft. and a stator for direct current excitation disposed around the rotary armature in opposition to the rotary armature. A multi-stator induction synchronous motor, characterized in that conductors communicating with a rotor core are connected in parallel via diodes between conductors located at an electrical angle of 180 degrees from each other in a portion not facing the stator. (3) The multi-stator induction synchronous motor according to claim (1) or (2), wherein the DC excitation circuit is a circuit in which a thyristor and a diode are connected in parallel with opposite polarities to one phase of the stator winding. A multiple stator induction synchronous motor characterized by having a plurality of stators inserted therein.