JP2828319B2 - Two stator induction synchronous motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

 The present invention relates to a synchronous motor capable of starting an induction motor.

[Prior art]

In general, a synchronous motor requires a starter that accelerates the rotor to near the rotational speed of the rotating magnetic field generated by the stator winding, that is, near the synchronous speed, and DC excitation of the rotor winding. An induction synchronous motor was devised so that the synchronous motor itself would have a starting torque by omitting this starter, which requires a starter to short-circuit the number of rotor turns and start as an induction motor at startup. However, a brush is required for DC excitation of the rotor winding required for synchronous operation. That is, when the rotation speed of the rotor approaches the synchronous speed, the short circuit of the rotor winding is opened, and a DC current is supplied from an external DC power supply to the rotor winding via a brush to create a magnetic pole in the rotor. The magnetic poles are pulled by the rotating magnetic field generated by the stator winding, and the rotor rotates at a synchronous speed. Since this brush requires maintenance and inspection, maintenance costs are increased, and development of a brushless synchronous motor is desired. As the synchronous motor having the brushless structure, there are a permanent magnet type and a reluctance type conventionally. However, since the starting torque of the induction motor is small because the induction motor cannot be started, it is limited to a small capacity motor. In addition, the synchronous motor of the Landel type or the inductor type has a disadvantage that the configuration of the magnetic path is complicated and large. The same applies to a method using an AC exciter and a rotary rectifier. A brushless self-excited three-phase synchronous motor that uses a harmonic magnetic field generated by an inverter square wave voltage by connecting a diode to a rotor winding has a drawback that sufficient output cannot be obtained due to insufficient magnetomotive force of the rotor. Furthermore, a diode is inserted into one phase of the three-phase stator winding, and static excitation is superimposed on the positive-phase rotating magnetic field generated by the stator, and the AC voltage due to the static magnetic field is applied to the rotor winding rotating at the synchronous speed. There is a brushless self-excited three-phase synchronous motor that generates a synchronous torque by inducing a rotor winding by direct current excitation by rectifying this with a diode and applying a rotating magnetic field corresponding to the positive phase. Since the induction motor cannot be started, it is started by the eddy current of the rotor core, and has a disadvantage that the starting torque is small. In Japanese Patent Publication No. 54-34124, there is a method in which starting is performed by the principle of an induction machine, and synchronous operation is performed by forming a DC magnetic field in an axial direction and thereby forming a magnetic pole in a rotor core. There is a disadvantage that the generated torque is asymmetrical with respect to the rotating shaft and causes vibration of the shaft. Tokiko Sho 61-1992
Uses two rotating magnetic fields of four poles and eight poles without mutual interference, uses two phases of a three-phase rotor winding for synchronous operation, and short-circuits the remaining one phase and uses it for startup. However, there is a disadvantage that the starting torque is reduced due to the gelges phenomenon.

[Problems to be solved by the invention]

Accordingly, it is a technical object of the present invention to provide a synchronous motor that has a large starting torque, a large synchronous torque, does not require a brush, is easy to maintain and inspect, has a simple structure, and does not require a dedicated starter.

[Means for Solving the Problems]

In order to solve the above-mentioned problem, two rotor cores provided at an arbitrary interval on the same rotation axis are provided, and each of the two rotor cores has the same number of poles and has the same number of poles. A first rotor winding connected between the rotor cores;
A rotor having a number of poles different from the number of rotor windings and having a second rotor winding connected between the two rotor cores, and facing the two rotor cores, respectively. 2
And two stator cores, each having a number of poles equal to the number of poles of the first rotor winding. Two stators provided with exciting windings having the same number of poles, and provided between a connecting portion of the first rotor winding and a connecting portion of the second rotor winding. A rectifier circuit connected to rectify the output voltage of the second rotor winding and input the rectified output voltage to the first rotor winding; and a specific stator among the two stators is A voltage phase shifter that produces a 180 ° phase difference between the rotating magnetic field generated around the rotor core facing the rotating core and the rotating magnetic field generated around the rotor core facing the other stator. Thus, a two-stator induction synchronous motor was configured. Furthermore, according to the present invention, the voltage phase shifter comprises a rotating stator for mechanically rotating the position of one or both stator cores of the two stators, or one of the stators. A means for solving the above-mentioned problem is constituted by a switch for switching the terminal of the winding to the reverse polarity.

[Action]

The applicant of the present invention describes the details of the operation of the multiple stator induction motor and its voltage phase shifter in Japanese Patent Publication No. Hei 2-27920. However, in the case of the present invention, a case is described in which the voltage phase shifter operates so as to have a phase difference of 0 ° at startup and a phase difference of 180 ° during synchronous operation. The present invention relates to a first rotor winding, a second rotor winding having a different number of poles from the first rotor winding, and a first rotor winding and a stator winding having a copper pole number. And a second rotor winding and an excitation winding having the same number of poles as the second rotor winding. Each of the rotor and the stator acts only between the stator and the rotor having the same number of poles. It is based on the known theory that the rotating magnetic field due to the windings does not have an electromagnetic effect on the second rotor windings of different pole numbers. According to the present invention, at the time of startup, a voltage is induced in the first rotor winding having the same number of poles by the rotating magnetic field generated by the stator winding, and the rotor starts rotating. Further, the rotating magnetic field of the stator winding does not affect the second rotor winding having a different number of poles. At this time, the voltage phase shifter operates so that the voltages induced in the first rotor winding wound around the two rotor cores have the same phase, that is, the second phase wound around the two rotor cores. One of the rotor windings is operated such that a recirculating current flows, and the motor is started up as a general induction motor. After the start, when the rotation speed of the rotor increases and approaches the rotation speed of the rotating magnetic field, that is, the synchronous speed, the slip decreases and the induced voltage of the first rotor winding due to the rotating magnetic field of the stator decreases. Up to this point, the operation is as an induction motor, but when the slip S approaches S = 0.05, the synchronous operation starts. This is performed as follows. First, between the rotating magnetic field generated around one rotor core facing one of the two stators and the rotating magnetic field generated around the rotor core facing the other. Activate the voltage phase shifter to create a 180 ° phase difference. In this way, the current that has been flowing back through the first rotor windings provided on the two rotor cores no longer flows, and is provided at the connection between the first and second rotor windings. A current flows through the rectifier circuit. Further, when the rotor approaches the synchronous speed and the slip becomes zero, no current flows through the first rotor winding. Therefore, when the exciting winding provided on the stator core is actuated simultaneously with the operation of the voltage phase shifter, the exciting winding has the same number of poles as the second rotor winding of the rotor core. Regardless of the first rotor winding having a different number of poles, the second rotor winding is linked with the magnetic field of the excitation winding to induce an AC voltage. This AC voltage increases as the rotation speed of the rotor increases. Also, as described above, the excitation windings of the two stator cores are connected to each other by 18 ° so that the rotating magnetic field has a phase difference of 180 °.
By arranging and providing a phase difference of 0 °, the AC voltage induced in the second rotor winding does not return to the two second rotor windings, and the second rotor winding does not return. The current flows through the rectifier circuit provided at the connection portion of the wire. By inputting the current rectified by the rectifier circuit as an output of the rectifier circuit to the first rotor winding, the first rotor winding forms a magnetic pole, and the rotating magnetic field of the stator winding having the same number of poles. The rotor rotates at a synchronous speed. At this time, the second rotor winding receives the action of the magnetic field of the exciting winding having the same number of poles, and the first rotor winding receives the action of the rotating magnetic field of the stator winding of the same number of poles. It is clear that they do not interfere with each other. Here, considering the synchronous torque, the phase of the rotating magnetic field created by a specific stator among the two stators is shifted by 180 ° from that of the rotating magnetic field created by the other stators. Due to the direction of the current flowing through the second rotor winding of the rotor core facing the one stator due to the magnetic field of the exciting winding, and to the second rotor winding of the rotor core facing the other stator. Since the current flows in the opposite direction, the current flows into the rectifier circuit to create a magnetic pole in the first rotor winding, and the polarity of this magnetic pole matches the polarity of the rotating magnetic field with a 180 ° phase difference. Will do. Therefore, since the torque of the two rotors is applied, the induction synchronous motor is a two-stator, but the total capacity is the same as that of an induction synchronous motor having a conventional brush. As described above, the two-stator induction synchronous motor of the present invention
At the time of starting, the starting torque is large because the first rotor winding starts according to the principle of the conventional induction motor, so that no other special starting machine is required. In addition, at the synchronous speed, the first rotor winding forms a magnetic pole by the power generation operation of the excitation winding and the second stator winding and the operation of the rectifier circuit, so that the synchronous torque is large, and a brush or the like is used. It has become possible to provide a synchronous motor that does not require maintenance. As a voltage phase shifter, the present applicant has disclosed in Japanese Patent Publication No. 2-27.
No. 920 describes two methods, a method of changing the position of the stator by mechanically rotating it around a rotation axis, and a method of switching the connection of the stator winding by a switch. With the above configuration, it is possible to provide a synchronous motor that has a large starting torque and a large synchronous torque, does not require a brush, is easy to maintain and inspect, has a simple structure, and does not require a dedicated starting device. became. By the way, the power supply for exciting the stator winding can use not only a DC power supply but also an AC power supply of a commercial frequency or a variable frequency power supply using an inverter. It can be used in a single phase or in a three phase. By using the variable frequency power supply, it is possible to easily change the synchronous speed, and even in that case, it is possible to start with the starting torque of a normal induction motor, the field of use is greatly expanded, and it is possible to provide an inexpensive synchronous motor. became.

【Example】

The present invention will be described mainly as a two-stator induction synchronous motor. The connection of the stator windings may be any of parallel, series, star connection, and delta connection, and the same applies to the rotor windings. The applicant has already described in detail Japanese Patent Publication No. 2-27920 the configuration and operation of an induction motor including a plurality of stators, which is a part of the configuration of the present invention. In other words, the rotating magnetic field generated around the stator where a specific stator among the plurality of stators faces the rotating stator and the rotating magnetic field generated around the rotor facing the other stator by the voltage phase shifter. For example, if the phase difference between the currents is 0 ° in phase, that is, the electrical angle, the current flowing through the rotor conductor returns to the rotor conductor. For example, if the electrical angle is 180 °, the current flowing through the rotor conductor is It describes in detail that the rotor conductor does not return and flows through a connecting member connecting the rotor conductors between the rotor cores. Further, as for the configuration of the voltage phase device, there are shown those for rotating the stator and those for switching the connection of the stator winding. In the present invention, particularly, the switching of the connection of the stator winding is performed. When the voltage phase shifter is constructed by performing the above operation, the electrical angle can be instantaneously switched from 0 ° to 180 °, so that it is easy to pull in the synchronous speed. If a sensor that detects the rotational speed, an excitation circuit, and a control device for the voltage phase device are provided and connected, the pull-in to the synchronous speed can be automated, and even if a step-out occurs, the sensor that detects the rotational speed Can be switched immediately from the synchronous operation to the operation of the induction motor, and self-prevention can be easily performed without suddenly stopping from step-out as in a general synchronous motor. A first embodiment of the present invention will be described with reference to FIG. First, reference numeral 20 indicates the stator side of a two-stator induction synchronous motor. Reference numeral 30 also indicates the rotor side. On the stator side 20, stator windings 21 and 22 are provided on each of two stator cores (not shown), and they are connected in series Y and connected to three-phase AC power sources R, S and T. I have. Exciting windings are further provided on each of the two stator cores on the stator side 20.
41, 42, a DC power supply 43 and an open / close switch SW2 are provided.
On the other hand, first rotor windings 31, 32 are provided on two rotor cores (not shown) provided on the same rotation axis on the rotor side 30, and they are connected in parallel. Further rotor side 30
Has a second rotor winding on each of the two rotor cores
33 and 34 are provided and they are connected in parallel. The number of poles of the first rotor windings 31 and 32 and the number of poles of the stator windings 21 and 22 are made to coincide with each other by four poles, and the number of poles of the second rotor windings 33 and 34 and the exciting winding 41 , 42 are matched with 8 poles. Further, a rectifying circuit 35 for rectifying the output of the second rotor windings 33 and 34 is provided at a connecting portion of the rotor winding between the two rotor cores, and an output terminal of the rectifying circuit 35 is connected to a diode 36.
Are connected to the connection portions of the first rotor windings 31 and 32 through the connection. Here, the first rotor winding 31 facing the stator winding 21
The voltage induced in the second rotor winding 33 is E in the illustrated direction, and the voltage induced in the second rotor winding 33 is e in the illustrated direction. The voltage induced in the first rotor winding 32 facing the stator winding 22 is Eε ^{jθ in the} illustrated direction, and the voltage induced in the second rotor winding 34 is eε ^{jθ in the} illustrated direction. And Here, θ is the phase difference angle of the voltage. The operation of the above configuration will be described. First, at startup,
When the phase difference angle θ of the induced voltage of the first rotor windings 31 and 32 is θ =
When the stator windings 21 and 22 are connected so as to be 0 °, the three-phase AC power supplies R, S and T are turned on and activated. Thus the results in a rotating magnetic field of the respective stator windings 21, 22 from the three-phase AC power supply three-phase AC power source flows through common mode voltage to the first rotor winding 31 and 32 E, is Iipushiron ^j.theta. Induced Is done. In this case, since the phase difference angle θ of the induced voltage is θ = 0, the current flowing through the first rotor windings 31 and 32 flows so as to return the two windings, and the rotor is driven by the principle of the induction motor. Activate (FIG. 2).
Here, since the number of poles of the second rotor windings 33 and 34 is eight, and the number of poles of the stator windings 21 and 22 is four, there is no mutual interference.
No voltage is induced in the second rotor windings 33, 34 depending on the rotating magnetic field generated by the stator windings 21, 22. Therefore, the second rotor windings 33 and 34 do not participate during startup. That is, the starting is performed with the same characteristics as the conventional induction motor, the starting torque is large, and a separate starting machine is not required. After startup, the rotation speed of the rotor increases and the stator windings 21 and 2
When the rotation speed approaches the rotation speed of the four-pole rotating magnetic field, that is, the synchronization speed of the four poles, the slip S decreases and the trigger voltage E of the first rotor windings 31 and 32 decreases. Up to this point, the operation is as an induction motor, but when the slip S approaches S = 0.05, the operation is introduced into the synchronous operation. This is performed as follows. First, the position of one of the two stator windings 21, 22, for example, the stator winding 22, is changed by rotating the core of the stator around a rotation axis by a voltage phase shifter, thereby changing the two stator windings. The phase difference angle θ between the two rotating magnetic fields formed by the windings 21 and 22 is set to θ = 180 °. In this case, the first
, The phase difference angle θ of the induced voltages of the rotor windings 31 and 32 becomes θ = 180 ° and Eε ^jθ = −E.
The current recirculating from 31 to the rotor winding 32 stops flowing, and the operation as the induction motor is lost. Therefore, excitation windings 41 and 42 provided on each of the two stator cores are operated. Here, a DC excitation circuit is shown. That is, the exciting windings 41 and 42 are connected in series as shown
When W2 is closed and a DC current flows from the DC power supply 43 to generate an 8-pole static magnetic field, the AC power supplies e and eε are applied to the second rotor windings 33 and 34.
^jθ is induced. Since θ = 180 ° due to the rotation of the stator core as described above, eε ^jθ = −e
become. Therefore, the current flowing through the second rotor windings 33 and 34 flows from the connection portion thereof toward the rectifier circuit 35, and this current is rectified and is passed through the diode 36 to the first rotor windings 31 and 32. The DC current flows from the connection portion to the rotor windings 31 and 32, and the DC current causes the rotor windings 31 and 32 to generate four magnetic poles. A synchronous torque is generated by the magnetic field, and the rotor enters synchronous operation. Here, the number of poles of the first rotor windings 31, 32 and the excitation windings 41,
Since the number of poles of 42 is different, there is no mutual interference between them.The number of poles of the stator windings 21, 22 and the number of poles of the exciting windings 41, 42 are also different, so there is no mutual interference between them, and the rotor is pure. The motor is operated as a four-pole synchronous motor, and the synchronous torque shown in FIG. 2 is large. Next, let's consider the case of step-out. When the step-out occurs, the induced voltages E and -E of the first rotor windings 31 and 32 due to the four-pole rotating magnetic field generated by the stator windings 21 and 22 increase. A rectified current flows through the first rotor windings 31 and 32 via the circuit 35, and an action of preventing step-out occurs. Considering the synchronous torque, the stator winding and the exciting winding are simultaneously rotated by the rotation of the stator by the voltage phase device during the synchronous operation, and the phase of the rotating magnetic field generated by the stator winding 22 is fixed. Since it is 180 ° out of phase with that of the slave winding 21, the second magnetic field generated by the exciting windings 41 and 42 causes the second
The relationship of the polarity of the magnetic poles of the first rotor windings 31 and 32 due to the rectifier circuit flowing through the rotor windings 33 and 34, the rectifier circuit 35, and the diode 36 becomes relatively equal to that of the rotating magnetic field, and the synchronous torque becomes The two rotor cores have the same direction, and the synchronous torques are to be added. Thus, the induction synchronous motor of the present invention is a two-stator, but the total capacity is the same as that of the conventional synchronous motor having a brush. The same is true. As described above, the two-stator induction synchronous motor of the present invention
At the time of starting, since the starting is performed based on the principle of the conventional induction motor, the starting torque is large, so that no other special starting machine is required. In the synchronous operation, a static magnetic field that does not interfere with the rotating magnetic field generated by the stator winding is used, so that a synchronous motor having a large synchronous torque and requiring no maintenance such as a brush can be provided. In the present embodiment, a method of rotating one stator core around the rotation axis as a voltage phase shifter for providing a phase difference to the induction voltage of the rotor winding has been described. That is, the phase difference angle θ is electrically changed to θ = 0 by changing the connection of
It is also possible to switch from ゜ to θ = 180 °. The details of the voltage phase shifter by connection switching are described in Japanese Patent Publication No. 2-27920, which is shown in FIG. 3 as a second embodiment. Since the configuration on the rotor side is the same as that of the first embodiment, only different portions will be described. The same symbols are used for the stator windings 21 and 22 and the excitation windings 41 and 42. A changeover switch SW1 is provided on the stator winding 22 of the second embodiment, and the polarity of the stator winding 22 is switched by switching the switch SW1, so that the position between the stator winding 21 and the stator winding 22 is changed. Has an electrical phase difference θ of θ = 0 ° and θ = 180 °. Also, since the excitation windings 41 and 42 act only on the synchronous operation, if they are connected in advance so that the phase difference θ = 180 °, there is no need to change the connection of the excitation windings. It only needs to be activated. In this embodiment, a combination of 4 poles and 8 poles is described in order to prevent mutual interference between the rotating magnetic field and the stationary magnetic field.
A combination of poles is also conceivable, and the present invention is not limited to this. In this embodiment, a method using a commercial power supply as a power supply has been described, but it is also possible to operate at an arbitrary synchronous speed by using a variable frequency power supply such as an inverter.

【effect】

From the above configuration, the two-stator induction synchronous motor of the present invention
At the time of starting, it performs with the same torque characteristics as the conventional induction motor,
The slip S shifts from, for example, around S = 0.05 to the synchronous speed, and the motor operates with the torque characteristics of the synchronous motor. This two-stator induction synchronous motor does not require a starter or a brush, so not only is its structure and configuration simple, but it can also be started with the same torque characteristics as conventional induction motors, so that heavy loads can be maintained. Startup and synchronous operation are possible. By the way, the two-stator induction synchronous motor of the present invention has both the torque characteristics of the induction motor and the synchronous motor, so that the torque characteristics of either motor can be used.
This means that even if the motor loses synchronism during operation at the synchronous speed, the torque characteristic of the induction motor can be switched from the torque characteristic of the synchronous motor to the torque characteristic of the induction motor, so that the motor suddenly stops like a general synchronous motor. There is no. As described above, since there is no brush and no complicated structure is required, maintenance and inspection are easy, and a synchronous motor having a large starting torque and a large synchronous torque can be provided.

[Brief description of the drawings]

FIG. 1 is a simplified configuration diagram of a stator winding side and a rotor winding side showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of torque characteristics of a synchronous motor of the present invention, and FIG. It is another Example figure of the stator side by connection switching. 20 ... stator side, 21 ... stator winding, 22 ... stator winding, 30 ... rotor side, 31, 32 ... first rotor winding, 33,
34 ... second rotor winding, 35 ... rectifier circuit, 36 ... diode, 41,42 ... exciting winding, 43 ... DC power supply, R, S, T ...
... three-phase AC power supply, SW1 ... changeover switch, SW2 ... open / close switch.

Claims (3)

(57) [Claims] 1. Two rotor cores provided at an arbitrary interval on the same rotation axis, each of the two rotor cores having an arbitrary number of poles and having the same number of poles A first rotor winding connected between the child cores, and a second rotor having a number of poles different from the number of poles of the first rotor winding and connected between the two rotor cores A rotor having windings; and two stator cores circumferentially opposed to the two rotor cores, respectively, the first rotor being provided on each of the two stator cores. Two stators provided with a stator winding having a number of poles equal to the number of poles of the winding and an excitation winding having a number of poles equal to the number of poles of the second rotor winding; Is provided between the connection portion of the rotor windings and the connection portion of the second rotor windings, and rectifies the output voltage of the second rotor windings to rectify the output voltage to the first rotor windings. A rectifier circuit operatively connected to the rotator, and a rotating magnetic field generated around a rotor core in which a specific stator of the two stators faces the rectifier circuit, and a rotation field in which the other stator faces the rotor. A two-stator induction synchronous motor, comprising: a voltage phase shifter for generating a 180 ° phase difference between a rotating magnetic field generated around a stator core and a rotating magnetic field. 2. The two-stator induction synchronous motor according to claim 1, wherein said voltage phase shifter mechanically rotates the position of one or both stator cores of said two stators. A two-stator induction synchronous motor comprising a rotating stator. 3. The two-stator induction synchronous motor according to claim 1, wherein said voltage phase shifter comprises a switch for switching a terminal of one stator winding to a reverse polarity. Child induction synchronous motor.