JP3358666B2 - Synchronous motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a self- contained induction motor.
The present invention relates to a synchronous motor that starts up and switches to synchronous operation.

[0002]

2. Description of the Related Art A general synchronous motor has a starter for accelerating its rotor to a rotational speed of a rotating magnetic field generated by a stator winding, that is, near a synchronous speed, and a DC excitation for the rotor winding.
Brush and DC power supply are required.

[0003] An induction synchronous motor is one in which the starter is omitted and the synchronous motor itself has a starting torque. This does not require a start motor for starting the induction motor by short-circuiting the rotor winding on startup, requiring brushes for DC excitation of rotor windings 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. However ,
Since the brushed motor requires maintenance and inspection, maintenance costs are increased, and a self-starting synchronous motor having a brushless structure is desired.

As a synchronous motor of the brushless structure diode in the rotor winding - inverter by connecting the de - data - there is a square-wave voltage brushless self-excited three-phase synchronous motor utilizing harmonic magnetic field by This is disadvantageous in that sufficient output cannot be obtained due to insufficient field magnetomotive force of the rotor.

[0005] Further , the inverter-driven brushless described above.
A synchronous motor in which a stationary magnetic field is superimposed on a rotating magnetic field for the normal and reverse phases created by a stator by inserting a diode into one phase of a three-phase stator winding, and the rotor winding rotates near a synchronous speed. An AC voltage is induced in the wire by the stationary magnetic field and the rotating magnetic field of the opposite phase , and this is rectified by a diode to excite the rotor windings to direct current and apply the rotating magnetic field of the positive phase to generate the synchronous torque. Although there are brushless self-excited three-phase synchronous electric motor that generates, this
In this case, since the induction motor cannot be started, the rotor is started by the eddy current of the rotor core, and there is a disadvantage that the starting torque is small.

[0006]

From the above, it is possible to easily shift from induction motor operation to synchronous operation while having the same starting torque and simplicity of maintenance as those of a general induction motor, and furthermore, the synchronous torque Large and brushless for easy maintenance
It is a technical task to provide a simple synchronous motor.

[0007]

In order to solve the above-mentioned problems, the present applicant has two rotor cores provided at arbitrary intervals on the same rotating shaft, and the two rotor cores are provided. A rotor in which rotor windings are provided in each of the cores and connected in series, and a diode is connected in parallel to a connection point of the rotor windings, and a rotor is provided facing the two rotor cores. Established 2
And a main winding magnetically coupled to the rotor winding and a main winding , respectively, each of the two stator cores .
Excitation windings in which a voltage is induced by the magnetic field of the wire are provided, and two stators in which excitation windings of two stator cores are connected in series via a diode; and two stators. core
Of each primary winding of a rotating magnetic field generated around the rotor core in which one of the main rotating magnetic field produced around the rotor core windings facing to the other main windings facing thereto In the meantime, a phase shift device for generating two phase differences at the time of starting and at the time of synchronizing is provided.

In addition, at an arbitrary interval on the same rotation axis,
It has two rotor cores provided, and the two rotor cores
Provide three-phase rotor windings for each and connect them in series.
And a diode connected in parallel to the rotor winding connection point.
And a rotor facing the two rotor cores.
Having two stator cores arranged therearound, wherein the two stator cores
Each of the three phases magnetically coupled with the rotor winding
Voltage is induced by the main winding and the rotating magnetic field of the main winding.
And the excitation windings of the two stator cores are provided.
Two fixed magnetic windings connected in series via a diode
And one of the main windings of each of the two stator cores.
Main winding is formed around the opposing rotor core
The circumference of the rotor core where the rotating magnetic field and other main windings face it
Synchronize with the rotating magnetic field generated in the
Phase shift device for generating two phase differences of 180 ° when inserted
And was constituted by. In the above synchronous motor,
The phase shifter is one of the two stators
Is it a switch that switches the connection of the main winding to the power supply?
The present invention is a means for solving the above-mentioned problem. Further, the excitation winding may be a single-phase winding or a three-phase winding.
You may.

[0009]

The applicant of the present invention discloses an operation of a phase shifter provided in an induction motor having a plurality of stators.
No. 4 explains the details.

According to the present invention, there are provided two rotor cores provided at an arbitrary interval on the same rotation axis, and a rotor winding is provided on each of the two rotor cores to form a series connection. And a rotor having a diode connected in parallel to a connection point of the rotor windings, and two stator cores circumferentially opposed to the two rotor cores. Each of the two stator cores is provided with a main winding magnetically coupled to the rotor winding and an excitation winding whose voltage is induced by the magnetic field of the main winding. Stators in which excitation windings of two stator cores are connected in series via a diode;
Of each of the main windings of the number of stator cores, one primary winding
Between the rotating magnetic field generated around the rotor core where the wire faces it and the rotating magnetic field generated around the rotor core where the other main winding faces it, there are two < and a phase shifter for generating a phase difference.

According to this configuration, at the time of startup, the rotating magnetic field of the main winding provided on each of the two stator cores causes
A current circulating through the rotor windings of the two rotor cores flows so that the voltages induced in the rotor windings of the two rotor cores have the same phase, and the current flows through the connection points of the rotor windings. diode provided in parallel - to de start by operating the phase shifting device so no current flows as a general induction motor. At this time, voltages are simultaneously induced in the exciting windings.
Voltage, because each occurs in the reverse direction diode - not the circulating current flowing through the de, the resulting excitation windings
Current does not flow.

After startup, the rotation speed of the rotor increases and approaches the rotation speed of the rotating magnetic field, that is, the synchronous speed . Up to this point, the operation is as an induction motor . Next, the slip is S = 0.
When the phase shift device is operated when approaching 05, the motor enters a synchronous operation. This works as follows.

A rotating magnetic field generated around a rotor core in which one of the two stator main windings faces the rotor core and a rotor core in which the other stator main winding faces the rotor core The phase shift device is operated so as to generate a phase difference of θ = 180 ° with the rotating magnetic field generated around the phase shifter.

The voltages induced in the two rotor windings by these rotating magnetic fields have a phase difference angle of 180 °.
Eliminating circulating current flows which has been flowing to Re, diode provided in parallel to the connection point of the rotor winding - so the current flows through the de. At this time, diode the excitation winding connected in series - so through a de voltage in the same direction to induce diode
The rectified current flows through the excitation winding ,
The two excitation windings stationary magnetic field-of-phase difference of 180 ° are made. A voltage is induced in the two rotor windings by the static magnetic field, and a circulating current does not flow due to this voltage.
A rectified current flows through a diode provided in parallel with the connection point between the rotor windings . Accordingly, the DC component by rectifying a current flowing in the rotor windings, the rotor current
The motor is excited to form a magnetic pole, and a synchronous torque is generated between the magnetic field and the rotating magnetic field of the main winding of the stator, so that the motor operates synchronously.

Considering the synchronous torque, the phase of the rotating magnetic field generated by one of the two stators is shifted by 180 ° from the phase of the rotating magnetic field generated by the other stator. However, due to the static magnetic field of the excitation winding, the direction of the current rectified by the diode flowing through the rotor winding of the rotor facing one of the stators is also changed by the diode flowing through the other rotor winding.
In this case, the synchronous torque is in the same direction in all the rotors, and the synchronous torques are all added, and the synchronous motor of the present invention has two synchronous motors. Although it is a stator, its total capacity is equivalent to an induction synchronous motor having a conventional brush.

A rectified DC current flows through the rotor winding by a voltage induced in the rotor by the static magnetic field of the exciting winding,
Since the rotor winding acts as a DC field winding , it is possible to provide a synchronous motor that has a large synchronous torque and does not require maintenance such as a brush.

As described above, the switching from the induction motor to the synchronous motor is performed by switching by the phase shift device. This phase shift device is configured to change the phase of the rotating magnetic field generated by one of the two stators. A phase difference angle of θ = 180 ° in electrical angle is provided between the phase of the rotating magnetic field produced by another stator and the stator winding of one of the two stators in the present invention. The terminals of the stator windings are switched by switches so that the polarities of the wires are switched, and the terminals are connected to a power supply. In addition, as a method of providing a phase difference, it is also possible to provide the phase difference by rotating one of the stators about a rotation axis. However, in a method in which switching needs to be performed instantaneously as in the present invention. Can be quickly and accurately switched by a switch.

Incidentally, the stator excitation winding can be any of single phase and three phase.

[0019]

As described above, the synchronous motor of the present invention has the following features.
Start performed in torque characteristics as in the conventional induction motor, times
The rotator speed shifts from, for example, near the slip S = 0.05 to the synchronous speed, and the motor is operated with the torque characteristics of the synchronous motor. This synchronous motor does not require a starter, a DC power supply, or a brush, so not only is its structure and configuration simple, but it can also be started with the same torque characteristics as a conventional induction motor, and It is possible to shift from startup to synchronization even if it is still running.

By the way, the synchronous motor of the present invention has the torque characteristics of both the induction motor and the synchronous motor.
The torque characteristics of either motor can be used. This means that the motor can be switched from the torque characteristic of the synchronous motor to the torque characteristic of the induction motor even when stepping out for some reason during operation at the synchronous speed. it is possible to stop the
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 can be provided.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, two main stator windings are connected in parallel to a power supply, and the windings are connected in a star connection .
Although an example will be described, the power supply may be connected in series or in a delta connection, and the present invention is not limited to this example. The same applies to the case of the rotor winding.

The applicant has already described in detail Japanese Patent Publication No. 2-27920 the structure and operation of an induction motor comprising a plurality of stators, which is a part of the structure of the present invention. For example, among a plurality of stators, a rotating magnetic field is generated around a rotor facing a specific stator and a rotating magnetic field is generated around a rotor facing the other stator. For example, if the phase difference between and 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 °,
It is described in detail that a current flowing through the rotor conductor flows through a connecting member connecting the rotor conductors between the rotor cores.

Further, the configuration of the phase shift device includes a device for rotating the stator, a device for switching the connection of the stator main winding, and the like.
Especially phase shifting device for switching the polarity of the stator main winding
In this configuration, the electrical angle can be switched from 0 ° to 180 ° instantaneously, so that it is easy to pull in the synchronous speed. If a sensor for detecting the rotational speed and a control device for the phase shift device are provided and communicated with each other, the pull-in to the synchronous speed can be automated, and even in the event of a loss of synchronism, the signal from the sensor for detecting the rotational speed will be It is possible to immediately switch from synchronous operation to operation of the induction motor, and it is possible to easily prevent an accident without suddenly stopping from step-out as in a general synchronous motor.

An embodiment of the present invention will be described with reference to FIG. FIG. 1 shows only the stator and rotor windings of a synchronous motor according to the present invention. First, reference numeral 1 denotes the stator side of the synchronous motor, and reference numeral 2 denotes the rotor side.

First, on the stator side 1, a three-phase AC power source is provided in which a first main winding 3 and a second main winding 4 in a star connection are provided in each of two stator cores (omitted). 5 is connected. Further, on the stator side 1, single-phase excitation windings 6 and 7 are provided on each of the two stator cores, and these excitation windings 6 and 7 are further connected in series via a diode 8. Connected to

On the other hand, on the rotor side 2, rotor windings 9, 10 are provided on each of two rotor cores (omitted), and these rotor windings 9, 10 are connected in series. Diodes 11 and 12 are connected in parallel to the connection points of the windings 9 and 10.

In the second main winding 4 of the stator 1, switches 13 and 14 are provided at both ends of the windings 4R, 4S and 4T of each phase of the main winding 4 so as to switch the polarity of the windings. To constitute the phase shifter 15.

Here, the exciting winding 6 facing the first main winding 3
The voltage induced by the E1, the voltage E1ipushiron ^j.theta. Induced in the excitation winding 7 which faces the second main winding 4. The voltage induced in the rotor winding 9 facing the first main winding 3 is represented by E
2, and the voltage induced in the rotor winding 10 which faces the second main winding 4 and E2ε ^jθ. Here, θ is the phase difference angle of the voltage.

The starting of the synchronous motor of the present invention having the above-described respective windings will be described. The switches 13 and 14 of the phase shifter 15 of the second main winding 4 are turned on to the A side, and the first main winding 3 and the second main winding 4 are turned on in parallel to the power supply 5. In this case, since the phase shifter 15 is not operating, θ = 0. The excitation windings 6 and 7 have a voltage E due to the rotating magnetic field.
1, although E1ipushiron ^j.theta. Is induced, also phase shifting device diode because a theta = 0 since no action - circulating electric current through the de 8 does not flow. On the other hand, the rotor windings 9 and 10 have voltages E2 and E2ε ^jθ due to the rotating magnetic field of the main windings 3 and 4, respectively.
Is induced, but θ = 0 because the phase shifter is not operating.
Therefore, a circulating current flows and starts as an induction motor.
In this case, no current flows through the diodes 11 and 12 because the terminal voltages of the diodes 11 and 12 are zero.

Next, a description will be given of the introduction to synchronization.
The switches 13 and 14 of the phase shifter 15 of the second main winding 4 are set to B
Side, the polarity of the second main winding 4 is reversed, and the first and second
The main windings 3 and 4 are supplied in parallel to R, S and T of the power supply 5.
In this case, the phase difference angle θ becomes 180 °. Voltage induced to the excitation winding 6 and 7 E1, ^E1ε j180 to the exciting windings 6 and 7 since the ^degree next ^E1ε j180 ^° = -E1 diode - is rectified through de 8 circulating electric current flows, whereby the stationary A magnetic field is created. When the synchronous speed is reached, the induced voltages E2 and E2ε ^jθ of the rotor windings 9 and 10 due to the rotating magnetic field of the main windings 3 and 4 are both zero, but the excitation windings 6 and 7
A voltage E is applied to the rotor windings 9 and 10 by the static magnetic field created by
2, E2ε ^{j180 °} is induced. In this case, θ = 180 °, so that E2ε ^{j180 °} = −E2, so that no circulating current flows through the rotor windings 9, 10 and the diodes 11, 1
2, the current rectified flows through the rotor windings 9, 10, and the rotor windings 9, 10 are excited by a DC component to form magnetic poles, and have a torque between the rotating magnetic fields of the main windings 3, 4. Occurs, leading to synchronous operation.

The excitation winding may have three phases. In this case, the diode connects the first and second excitation windings 6 and 7 in series via the diodes 16 and 17 as shown in FIG.

With the above configuration, the synchronous motor according to the present invention starts at a startup with a phase difference angle θ = 0 ° and the same torque characteristics as a conventional induction motor , and the slip S becomes, for example, around S = 0.05. the phase difference angle by switching the switch of the phase shift device when it is a theta = 180 degrees, is intended to operate in the torque characteristics of the synchronous motor shifts to synchronous speed. Such a configuration, the synchronous motor of the present invention starts machine or DC power supply, also does not require a brush, not only the structure and configuration is simplified, can be activated in the same torque characteristics of the conventional induction motor Therefore, even if a heavy load is applied, it is possible to shift from startup to synchronization simply by switching the switch of the phase shifter .

[Brief description of the drawings]

FIG. 1 is a diagram showing only a winding portion of a stator and a rotor of a synchronous motor according to the present invention.

FIG. 2 is a diagram showing another embodiment of the exciting winding according to the synchronous motor of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator side 2 Rotor side 3 1st main winding 4 2nd main winding 5 Three phase alternating current power supply 6 Excitation winding 7 Excitation winding 8 Diode 9 Rotor winding 10 Rotor winding 11 Diode 12 Diode 13 Switch 14 Switch 15 Phase shifter 16 Diode 17 Diode

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02K 19/14 H02P 1/46 H02P 7/36 H02K 16/00 H02K 17/00

Claims (5)

(57) [Claims] 1. Two rotor cores provided at an arbitrary interval on the same rotating shaft, and a rotor winding is provided on each of the two rotor cores and connected in series. And a rotor having a diode connected in parallel to a connection point of the rotor windings, and two stator cores circumferentially opposed to the two rotor cores. A main winding magnetically coupled to the rotor winding and a main winding;
Excitation windings in which a voltage is induced by the magnetic field of the wire are provided, and two stators in which excitation windings of two stator cores are connected in series via a diode; and two stators. core
Of each primary winding of a rotating magnetic field generated around the rotor core in which one of the main rotating magnetic field produced around the rotor core windings facing to the other main windings facing thereto A synchronous motor comprising: a phase shifter for generating two phase differences between a start and a synchronous pull-in . 2. Arrangements are provided at arbitrary intervals on the same rotation axis.
Having two rotor cores, each of the two rotor cores;
With three-phase rotor windings and connect them in series.
A diode is connected in parallel with the connection point of the rotor winding.
Rotor and the two rotor cores are circumferentially opposed to each other.
Having two stator cores, wherein the two stator cores
In each case, a three-phase main winding magnetically coupled to the rotor winding
And the excitation induced by the rotating magnetic field of the main winding.
Magnetic windings and excitation windings of two stator cores
, Two stators connected in series via a diode,
One of the main windings of each of the two stator cores
Rotational magnets generated around the rotor core where the windings face it
Around the rotor core where the field and other main windings face
0 ° at start-up between the rotating magnetic field
And a phase shift device for generating two phase differences of 180 °
A synchronous motor characterized by the above configuration. 3. A phase shifter according to claim 1, wherein
Switch to switch the connection of one of the stator main windings to the power supply
And a switching switch.
Is a synchronous motor according to 2. 4. The excitation winding is a single-phase winding.
The synchronous motor according to claim 1. 5. The excitation winding is a three-phase winding.
The synchronous motor according to claim 1.