JPH01177848A - Plural stator induction motor - Google Patents

Abstract

PURPOSE:To perform a smooth speed-shift without impact at the time of accelerating and decelerating, and to obtain a wide speed shifting range by providing a revolving unit at least at one stator, and coupling it through a controller with a pole change switching unit. CONSTITUTION:A plurality of rotor cores 2, 3 are mounted on the same rotary shaft 4, and conductors 6 are mounted through the cores. The ends of the conductors 6 are short-circuited, and the cores are coupled by a resistance material thereby to form a rotor 7. A plurality of stators 24, 25 are mounted oppositely at the cores 2, 3. Windings which can be changed to a plurality of number of poles are respectively wound on the stators. A revolving unit (motor 30, gears 29, 31) for forming a phase difference to other stator is provided on at least one stator 24. The revolving unit is coupled to the pole change unit of the stator through a controller 42.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a transmission device for a multi-stator induction motor.

[Prior art and its problems]

One way to control the speed of an induction motor is to change the power supply frequency. Although this method allows for continuous and wide-range speed control, it requires an expensive frequency converter, and in the process of converting alternating current to direct current and then back to alternating current using the frequency converter, harmonics and Radio waves are generated, which cause computers,
This may lead to damage such as malfunction of various other electrical control equipment or overheating of capacitors. Among these, countermeasures against harmonic interference can be taken by installing filters, but installing filters is costly. Furthermore, the method of changing the power supply frequency has drawbacks such as generally insufficient performance at low speeds.

Yet another method of controlling speed by varying the voltage of the power supply is
Although speed control can be performed continuously, it has the disadvantage of poor efficiency, especially in the low speed range.

For wire-wound motors, there is a method of controlling the speed by changing the secondary resistance and changing the slip. Although this method allows continuous speed control with relative ease, it requires maintenance and inspection due to wear and tear on the brushes because resistance is inserted into the rotor winding circuit from the outside via the brushes and slip ring. do. Note that in a squirrel cage induction motor, speed control cannot be performed by changing the secondary resistance.

Pole change motors are capable of stepwise speed control.
Two or more sets of independent windings with different numbers of poles are wound on the same core, or the same number of poles is obtained by switching the connections of the same winding to change the speed. Although this device can change speed in stages by providing a large number of poles, it cannot change speed continuously to an arbitrary speed. Further, there are other problems such as an impact caused by torque fluctuation when switching the number of poles, and an increase in size due to the large number of poles.

Techniques to deal with the above problems include, for example, Japanese Patent Application Laid-open No. 5
There is one disclosed in Japanese Patent No. 4-29005. This thing consists of two sets of rotor cores installed coaxially and two sets of rotor cores installed on the same axis.
Two sets of stators each have independent stator windings facing the set of rotor cores, and are installed in common across the two sets of rotor cores, and are connected to each other via short-circuit rings at both ends. It is equipped with a squirrel-cage conductor that short-circuits between the two sets of rotor cores, and a high-resistance element that short-circuits between the squirrel-cage conductors at the center of the squirrel-cage conductors between two sets of rotor cores. This is a twin core cage carving motive characterized by shifting the phase of the two irons by 180 degrees and supplying power in phase with each other during operation after startup. This electric motor increases the starting torque and improves starting characteristics by shifting the phases of the stator windings by 180 degrees when starting, and during operation, the phases of the stator windings are aligned to achieve normal torque. It is characterized by the fact that it can be operated according to its characteristics. Therefore, this electric motor can set the phase shift of the rotating magnetic field to 0° and 180°, and although it has the effect of improving starting characteristics, it is not originally a variable speed electric motor, so it is not suitable for loads that require speed changes. It is not suitable as a power source for

In addition, in the above-mentioned Japanese Patent Application Laid-open No. 54-29005, in order to alleviate the shock caused by sudden fluctuations in torque accompanying the transition from startup to steady operation, both stator windings are temporarily connected in series to the power supply circuit. Although providing an intermediate step for connection is described as an example, this does not necessarily make it possible to control the speed change. Moreover, by switching to series, the voltage applied to the stator is halved, so the torque is reduced to 1/4, and together with this, the speed change control becomes completely impossible, which is the main point disclosed in this publication. This is obvious from the fact that it is not intended for gear shifting.

[Purpose of the invention]

The present invention solves the above-mentioned drawbacks of the prior art and provides a multi-stator induction motor that has excellent torque characteristics, can set and hold any desired speed over a wide range of speed control ranges, and can change speeds without impact. The purpose is to

The multi-stator induction motor of the present invention is used by being connected to a single-phase or three-phase power supply, and the rotor can be of a normal squirrel cage type, double cage type, deep groove cage type, special squirrel cage type, etc. It can be applied to any type of equipment.

[Means for solving problems]

In order to achieve the above-mentioned technical problem, the present invention has a plurality of rotor cores attached to the same rotating shaft at arbitrary intervals, and has a plurality of rotor cores that penetrate through each of the plurality of rotor cores. A rotor in which each of the plurality of installed conductors is short-circuited at both ends, and the plurality of conductors are integrally formed by connecting the plurality of conductors with a resistance material between the plurality of rotor cores, and the plurality of conductors are integrally formed. a plurality of stators each having a winding that can be switched to a plurality of types of pole numbers provided on the outer periphery facing each rotor core; and a plurality of stators provided on at least one of the plurality of stators. a rotating device that rotates concentrically with the rotor, and a pole number switching device that switches the number of poles of the winding;
The rotation device and the pole number switching device are connected via a control device to solve the problem.

[For production]

The present invention provides a rotation device for at least one stator among a plurality of stators, and rotates the stator to generate a voltage induced in the conductor portion of the rotor facing each of the arbitrary stators and other stators. In order to increase or decrease the voltage induced in the rotor conductors by creating a phase shift in the rotor conductors, a plurality of conductors are connected between a plurality of rotor cores via a resistive material, so that the phase shift can be controlled. In response to this, current flows from the plurality of conductors to the resistive material, and a strong rotational torque can be generated. In addition, each stator is equipped with a winding that can be switched to multiple types of pole numbers, and the pole number switching device and control device are connected to the rotation device, so that a large number of poles can be used between the stators. It starts at a position where the amount of rotation is large, that is, a position where the phase difference is large, and the amount of rotation is gradually reduced to accelerate until the phase difference reaches 0°. When the rotational position with a phase difference of 0° is switched to a small number of poles, the phase difference is around 180°. Since the output torques of the motors are set to be approximately the same at the time of switching, there is no impact when increasing speed, and there is similarly no impact during deceleration, so the speed can be changed smoothly.

〔Example〕

Embodiments of the present invention will be described based on FIGS. 1 to 7.

One embodiment of the present invention will be explained with reference to FIGS. 1 to 3. Reference numeral 1 denotes a multi-stator induction motor according to the present invention, and the multi-stator induction motor 1 has the following configuration. Rotor cores 2 and 3 made of magnetic material are mounted on the rotor shaft 4 with arbitrary intervals, and a non-magnetic core 5 is interposed between the rotor cores 2 and 3, or a space is provided between the rotor cores 2 and 3. If leakage reactance is not important, the purpose can be achieved by providing a continuous rotor core and insulating the rotor core portion that does not face the stator (24, 25) from the conductor. A plurality of conductors 6 installed in the rotor core 2゜3 are connected to each other through the rotor cores 2 and 3 to form an integral rotor 7, and a plurality of conductors 6 are connected in series. Conductor 6...
Both ends of . are short-circuited by a short-circuit ring 8.8. In addition, a plurality of passages [12...] are provided in the rotor core 2.3 and the non-magnetic core 5, which communicate with both sides 10.11 of the rotor 7, and rotate at right angles from the ventilation barrel 12... A plurality of ventilation holes 13 are bored through the outer circumference of the child 7. A conductor 6 installed in the rotor 7 is connected to the non-magnetic core 5 between the rotor cores 2 and 3 through a resistive material 9 that conducts electricity when a current with an arbitrary vector difference flows through each of the non-magnetic cores 5. That is, they are connected via a resistive material made of nichrome wire, carbon-containing steel, conductive ceramic, or the like.

Bearings provided on both sides of the cylindrical machine frame 14! Ii! 15 and 16 are integrally assembled to the connecting rods 17 by tightening the nuts 18. Cooling impellers 19.20 are mounted on both sides of the rotor 7, and both ends of the rotor shaft 4 are supported by bearings 21.21 fitted in bearing discs 15.16, allowing the rotor 7 to rotate freely. It's Toshide.

A first stator 24 and a second stator 25 having windings 22 and 23 on their outer sides facing the rotor cores 2 and 3 are arranged side by side in the machine frame 14, and the machine frame 14 and the first stator 24 are connected to each other. between sliding bearing 2
7 is installed, the sliding bearing 27 is fixed by a stop ring 26 fitted to the machine frame 14, and the second stator 25 is fixed to the machine frame 14 by a fixing ring 28. A gear 29 is fitted onto the outer peripheral surface of one side of the first stator 24 . A driving gear 31 is pivotally attached to a small motor 30 fixed to the outer periphery of the machine frame 14, and the driving gear 31 is engaged with a gear 29 fitted to the first stator 24. With this configuration, the first stator 24 rotates concentrically with the rotor 7 by the operation of the small motor 30, forming a rotating stator, and thus the rotation of the first stator 24 A voltage phase shifting device is constituted by the motor and the second stator 25.

A ventilation port 34 and a ventilation port 35 are bored on the outer periphery of the machine frame 14,
An exhaust fan 36 having a motor 37 is fixed to the exhaust port 35 to circulate air in the space 38 to the outside of the machine frame 14. In addition, a cooling roller 19.20 that rotates integrally with the rotor shaft 4
This is provided to take in air from the ventilation port 32 and distribute the air to the side portions 10 and 11, the ventilation body 12, and the ventilation port 13. Reference numeral 33 denotes a vent for air circulation, which is bored in a portion of the machine frame 14 facing the first stator 24 and the second stator 25.

Next, with reference to FIG. 2, the configuration of the means for detecting the rotational position of the first stator 24 will be described. A magnetic body 39 is fixed on the outer periphery of the rotating first stator 24, and a plurality of magnetic sensors 40 are provided at any part of the machine frame 14 facing the magnetic body 39.
Rotation position detectors 40 . Reference numeral 43 is a solenoid for opening or locking the rotation of the first stator 24, and the rotation of the stator can be opened or locked by any known actuation mechanism.

Another embodiment of the rotation mechanism and rotation position detection device will be described with reference to FIG.

A rotating shaft 45 is rotatably provided on a bearing 44 fixed to the machine frame 14 and is provided with a worm gear 46 that rotates integrally with the rotating shaft 45, and engages with the worm gear 29. At one end of the rotating shaft is a rotating pulse motor 4 that rotates in forward and reverse directions.
7 is provided concentrically with the rotating shaft 45, and the pulse motor 47 is fixed to the machine frame 14.

Next, with reference to FIG. 4, a description will be given of the connection between a winding wire wound around a plurality of stators that can be switched to a plurality of types of pole numbers, and a pole number switching device that switches the number of poles using a pole number changeover switch.

1st. Winding 2 applied to each of the second stators 24, 25
2.23 are each provided with a terminal that converts the number of poles to two. 1st. Each of the windings 22.23 of the second stator 24.25 has terminals U+, V+, W+ and U2. V2
．． W2, X+, Y+, and Z+ are provided, and the terminal U of the winding 23
2, V2. The terminal of W2 is connected via the pole number changeover switch S1,
In addition, the terminals U+, V+, and W+ are connected to the commercial three-phase power supply through the pole number changeover switch S4, and the terminals U1 and Connect each with a short circuit through S2, and winding 2
2 and the winding 23 are connected in series.

That is, the terminals X+, Y+, Z+ of the winding 23 are connected to the terminals U+, V+, W+ of the winding 22 via the pole number changeover switch S7, and the terminals U1 and Xl of the winding 22, terminals V1 and Y+, Terminals W1 and 71 are each short-circuited via a pole number changeover switch S3, and the short-circuited terminals can be short-circuited via a pole number changeover switch S6.

Furthermore, the terminals X+, Y+, and Z+ of the winding 23 are connected to the terminals U2. of the winding 22. W2. V2 via a pole number changeover switch S5, and terminals X+, Y+, and Z+ of the winding 22 are connected to a commercial three-phase power supply via a pole number changeover switch S8.

The operation of the above configuration will be explained below with reference to the drawings.

When the windings 22 of the first stator 24 are energized from a commercial three-phase power source, a rotating magnetic field is generated in the stator 24, 25, a voltage is induced in the rotor 7, and a current is generated in the conductors 6 of the rotor 7. The flow causes the rotor 7 to rotate.

When the rotation ω of the first stator 24 with respect to the second stator 25 is set to zero, each stator 24.25
There is no phase shift in the voltage induced in the conductor 6 of the rotor 7, and no current flows through the resistor 9, so in this state it has the same torque characteristics as a general induction motor. .

Next, a case will be described in which the small motor 30 is operated to rotate the first stator 24 by an electrical phase angle of Pθ. Here, P is the number of pole pairs, and θ is the mechanical rotation angle of the stator. The phases of the magnetic fluxes φ1 and φ2 of the rotating magnetic fields generated by the first stator 24 and the second stator 25 are shifted by Pθ with respect to any conductor 6 of the rotor 7, so that the first stator 24 and the second stator 25, the phase of the voltages 6+ and h induced in the conductors 6 of the rotor 7 is shifted by Pθ. Now, the conductor 6 of the rotor 7 is connected to the second stator 25...
The voltage ω induced in is used as a reference, and this voltage is set as ω=SE. Here, S is slip and E is the induced voltage when slip is 1. At this time, the conductor 6 and
The voltage 01 induced in ... is 6+ = 3 E 6"
', and since the resistive material 9 is provided between the rotor cores, a current corresponding to a vector difference due to a phase difference in voltage inevitably flows through the resistive material 9.

This has the same characteristics as shown in FIG. 5 when the secondary insertion resistance of a wire-wound induction motor is changed.

In FIG. 5, the horizontal axis S represents the slip, and S=0 represents the synchronous speed when the number of pole pairs is P. And the polar logarithm P+ (
When P+=2P), the synchronous speed is 51-0. The vertical axis T represents torque. A curve L1 in FIG. 5 is a torque characteristic curve at a rotation angle θ=0 when the motor is operated with the number of pole pairs P. In this case, the first stator 24 and the second stator 25
Since the phases of the induced voltages in the conductor 6 of the trochanter facing the same match, the phases of both rotor currents also match, and the rotor current flows through both rotor conductors without being shunted to the resistance material 9. and flows. Therefore, the torque characteristic is exactly the same as that of a known squirrel cage induction motor. Curve L4 has the number of pole pairs P and rotation angle θ=
This is a torque characteristic curve when operating at π/P. In this case, the conductor 6 of the squirrel cage rotor facing both stators...
Since the phase of the induced voltage of ・ is reversed, the phase of both rotor currents is also reversed, and the rotor current does not flow through both rotor conductors, but all of the rotor current flows through the resistor material 9. flows through. Therefore, the characteristics are the same as those obtained when a secondary resistance is inserted into a known wound induction motor, that is, when the resistance of the rotor conductor of a known squirrel induction motor is increased, and the resistance value of the resistor material 9 is When set to a given value,
Song 11L4 becomes almost a straight line. The characteristic curve for cases other than θ=0 and θ=π/P with the number of pole pairs P is, for example, 0 and θ1.
The characteristic curves for θ1 and θ2, where θ2<π/P, are curves L2 and L3 between curves L1 and 14. This change from curve L1 to curve L4 occurs when the resistance value of the secondary insertion resistor of a known wound induction motor is increased from zero or when the resistance value of the conductor of a known squirrel cage induction motor is increased. This is the same as the change in torque characteristics.

FIG. 6 shows the relationship between θ and the torque curve when θ is changed when P=2. 11 to L4 in FIG. 6 are rotation angles of 0. θ1. θ2. These are the positions showing the corresponding torque curves L1 to L4 in FIG. 5, such as at π/P.

For the same reason as mentioned above, the speed vs. torque characteristic curve when switching to the pole number P+=2P is θ=0 and θ=2π/
For P+, the curve is shown as [5, and for θ=π/P+ and θ=3π/P+, the curve is shown as L8. Further, the curves for θ1 and θ2, which are 0<θ1×θ2×π/P1′, have shapes shown by L6 and L7. FIG. 7 shows the relationship of the torque curve of θ when changing θ in the case of P+ = 4 (= 2P), which corresponds to FIG. This is the rotational position showing the torque curves L5 to L8 in the figure.

The number of pole pairs P is set so that the load speed vs. torque characteristic curve shown by the dashed line in FIG. A torque curve L4 of the electric motor when θ=π/P is designed. This can be easily done by adjusting the resistance value of the resistance material 9. In this way, at startup, θ=
3π/PI and set the number of pole pairs to Pl.

After starting, reduce the rotation angle and increase the speed, θ = 2π
/P+ reaches point D. When increasing the speed from point D in Figure 5, change the number of pole pairs from Pl to P at point D, and when decreasing the speed from point D, change the number of pole pairs from P to P at point D.
By switching to l, the torque curve of the electric motor is switched from L5 to 14 or from L4 to 15,
Torque fluctuations due to pole number change can be completely eliminated.

For the case of P=2 and P1=4, the fourth. To explain specifically how to increase the speed with reference to FIG. 5, first, at startup, the pole number changeover switch 34 is set at θ-3π/4. Input Sy and Ss, open the others, and set the number of pole pairs to 4. Then the speed reaches point A. θ to 3π
When the speed is sequentially decreased from /4 to θ=π/2+θ2, the speed reaches point B, when it is set to π/2+61, the speed reaches 0 point, and when it is set to θ−π/2, the speed reaches point D. Here, the number of poles changeover switch S4. Open S7゜S8 and at the same time turn the pole number changeover switch S+.

Turn on S2, 83, 85.36 and switch the number of pole pairs to 2. Even if only the number of pole pairs is changed, the speed remains at point D. Next, when θ is further decreased one after another until θ=θ2, the speed becomes E
When the point is reached and θ=θ1, the speed reaches 1 point and θ=0
Then, the speed will increase to point G. and,
When decelerating, the same effect can be achieved by performing the exact opposite operation.

When implementing the present invention, consideration should be given to variations in the torque characteristics of the motor and load and design errors, and also due to frequent pole number changes that occur near point A due to slight torque fluctuations associated with pole number changes. In order to prevent this, it is better to design the torque of curve L4 to be slightly lower than that shown in FIG. In this way, although some torque fluctuations will occur when changing the number of poles, frequent changes in the number of poles can be avoided.

Due to the rotation of the rotor 7, the cooling impeller 19°20 opens the machine frame 14 from the ventilation hole 32 bored in the bearing plate 15.16.
The outside air is sucked into the inside, and the first.
The second stator 24° 25 and the windings 22, 23 are ventilated and cooled, and the rotor core 2, 3, the conductors 6, . . . , resistance material 9 . . . etc. are cooled to stably perform their respective functions. Also, 1st. The rotation of the second stator 24, 25 is carried out by rotating the small motor 30 in forward and reverse directions using a switch, but this is not limited to the small motor 30, and other forward and reverse motors may also be used, as well as gas, liquid cylinders, etc. Any drive device such as a servo mechanism can be used.

If the stator is rotated at an arbitrary speed in relation to the operating speed of the drive device that rotates the stator, the rotor 7
It is possible to control the rate of change of the rotation speed of the motor.

The drive device shown in Fig. 3 is a pulse motor 47 and a gear 2.
The rotation amount and rotation speed can be controlled by the number of pulses sent from the control device 42 to the pulse motor 47 and the pulse interval. In this embodiment, the worm gear 46 also has the function of fixing rotation.

Furthermore, it is also possible to combine the multi-stator induction electric motor TA1 of the present invention with a conventionally known star-delta starting device.
This expands the starting and operating speed range of the electric motor, and enables use in high efficiency ranges.

In the present invention, each of the plurality of stators is provided with a winding that can be switched to a plurality of types of pole numbers. In some cases, the number of poles can be changed to a plurality of types by providing independent multiple windings and switching the windings.

In addition, the space between the rotor cores may be made of magnetic material, non-magnetic material, or space, and when using a resistive material, the resistive material is a connecting material that conducts electricity when an arbitrary voltage is applied. For example, it may be something like a diode.

〔Effect of the invention〕

As explained above, according to the present invention, at least one stator among a plurality of stators is provided with a rotation device to form a voltage phase device, and each of the other stators is provided with a rotation device. A phase difference is caused in the voltages induced in corresponding conductor parts, windings that can be switched to multiple types of pole numbers are applied to the plurality of stators, and the pole number switching device and the control device are connected to the rotating device. Because they are connected, when switching from a large number of poles to a small number of poles during speed increase, the output torque of the motor can be set to be almost the same in terms of load torque, so there is no shock, and there is no shock in deceleration as well. This provides remarkable effects such as smooth gear shifting and a wider gear shifting range than with a single pole.

[Brief explanation of the drawing]

Figures 1 to 7 show examples of the present invention, with Figure 1 being a side sectional view of a multi-stator induction motor, and Figure 2 showing a stator rotation mechanism and rotation position detection mechanism. 3 is a side sectional view, and FIG. 3 is an example of using a pulse motor for the rotation mechanism and detecting the rotation position using a memory/arithmetic circuit. FIG. Fig. 5 is a graph showing the slip and torque characteristics in connection with multiple poles. Figs. 6 and 7 show the relationship between the characteristic curves L1 to L8 in Fig. 5 and the rotation angle. FIG.

Claims (3)

[Claims] (1) It has a plurality of rotor cores attached to the same rotating shaft at arbitrary intervals, and each of the plurality of conductors is installed through each of the plurality of rotor cores. a rotor that is short-circuited at both ends and integrally formed by connecting the plurality of conductors with a resistive material between the plurality of rotor cores; and an outer peripheral portion facing each of the plurality of rotor cores. a plurality of stators provided with windings that can be switched to a plurality of types of pole numbers; and at least one of the plurality of stators rotates concentrically with the rotor provided on at least one stator. a rotating device for switching the number of poles of the winding; and a pole number switching device for switching the number of poles of the winding, and the rotating device and the pole number switching device are connected via a control device. induction motor. (2) In the multi-stator induction motor according to claim (1), the rotation device has a rotation angle detection device, and the control device uses a detected value of the rotation angle detection device. A multi-stator induction transmission machine that outputs a signal for switching the number of poles to the pole number switching device based on the above. (3) In the multi-stator induction motor according to claim (1), the number of poles of one of the windings is twice as large as the number of poles of the other, and the control device is configured to control the The number of poles is twice as large, and the rotation angle is the angle obtained by dividing three times the circumference by the number of poles of the larger number of poles.At the time of switching the number of poles, the rotation angle is twice the circumference of the larger pole. An angle divided by the polar logarithm of a number,
A multiple stator induction motor.