JP2020141504A - Dynamo-electric machine system and control method of induction rotary electric machine - Google Patents

Abstract

To improve performance of induction rotary electric machine.SOLUTION: A dynamo-electric machine system includes an induction rotary electric machine and a drive system. The induction rotary electric machine includes a shaft, a rotor and a stator. The rotor includes: a cylindrical magnet rotor placed on the outer peripheral side of the shaft and supported rotatably for the shaft; a cylindrical rotor core placed on the outer peripheral side of the magnet rotor and supported fixedly for the shaft; and multiple rotor coils or conductors provided on the outer peripheral surface of the rotor core. The stator includes a cylindrical stator core placed on the outer peripheral side of the rotor, and multiple stator coils provided on the inner peripheral surface of the stator core. The drive system controls the phase of the current so that the medial axis of a revolving magnetic field generated by the current flowing through the multiple stator coils is substantially aligned with the d-axis, i.e., the direction of magnetic flux generated by multiple magnetic poles of the magnet rotor.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rotary electric machine system and a control method for an induction rotary electric machine.

An example of an induction rotary electric machine is an induction motor or an induction generator. In an induction motor, an induced current is generated in the rotor of an electric conductor by a rotating magnetic field generated by a stator, and a rotational torque corresponding to slippage is generated.

Japanese Unexamined Patent Publication No. 2015-163028

Naoki Sugiyama, Kazuto Sakai, "High Torque Induction Machine with Magnet", 2018 IEEJ Industrial Application Division Conference, 3-16 (2018) Masanori Okayasu, Kazuto Sakai, "Fault Tolerance System for Multi-Inverter Electronics Motors", 2017 IEEJ National Convention, 4-050 (2017-3) Kengo Kawachi, Masanori Okayasu, Kazuto Sakai, "Examination of Pole Number Conversion of Multi-Inverter Electronics Motor by Slip Frequency Control", 2017 IEEJ National Convention, 4-051 (2017-3) Hideyuki Yano, Kazuto Sakai, "Control Characteristics of Pole Conversion of Multi-Inverter Motors", 2018 IEEJ National Convention, 5-109 (2018-3)

The induction motor is inferior in torque and efficiency to the permanent magnet motor, and the torque is small in the low speed rotation range and the medium speed rotation range even in the variable speed operation. Therefore, a magnet-combined induction motor has been proposed in which the rotor of the induction motor is provided with a permanent magnet to increase the torque.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the performance of a magnet-combined induction rotary electric machine.

In the induction rotary electric machine according to the present invention, the rotary electric machine system includes an induction rotary electric machine and a drive system. The induction rotary electric machine includes a shaft, a rotor, and a stator. The rotors are a cylindrical magnet rotor arranged on the outer peripheral side of the shaft and rotatably supported with respect to the shaft, and a cylindrical shape arranged on the outer peripheral side of the magnet rotor and fixedly supported with respect to the shaft. The rotor core and a plurality of rotor coils or conductors provided on the outer peripheral surface of the rotor core are provided. The stator is arranged on the outer peripheral side of the rotor and includes a cylindrical stator core and a plurality of stator coils provided on the inner peripheral surface of the stator core. In the drive system, the current is such that the central axis of the rotating magnetic field generated by the currents flowing through the plurality of stator coils and the d-axis which is the direction of the magnetic flux generated by the plurality of magnetic poles of the magnet rotor are approximately the same. Control the phase of.

According to the present invention, the performance of the induction rotary electric machine can be improved.

The figure which shows an example of the schematic structure of the electric motor system which concerns on 1st Embodiment. FIG. 5 is a cross-sectional view showing a first example of a schematic configuration of a rotor of an induction motor according to a first embodiment. The cross-sectional view which shows the 2nd example of the schematic structure of the rotor of the induction motor which concerns on 1st Embodiment. The conceptual diagram which shows the example of d-axis and q-axis. The block diagram which shows an example of the structure of the drive system which concerns on 1st Embodiment. The flowchart which shows an example of the processing of the drive system which concerns on 1st Embodiment. The flowchart which shows an example of the current phase determination processing which concerns on 1st Embodiment. The graph which shows an example of the relationship between the current phase and the torque of a magnet rotor in the rated current which concerns on 1st Embodiment. The graph which shows an example of the relationship between an electric angle and a magnetic flux density. The graph which shows an example of the time change of the torque from the transient state to the steady state of the induction motor which concerns on 1st Embodiment. The graph which shows an example of the time change of the torque from the transition state to the steady state of Comparative Example 1. The graph which shows an example of the control concept of the induction motor which concerns on 2nd Embodiment. The figure which shows 1st example of the schematic structure of the multi-inverter motor system which concerns on 2nd Embodiment. The figure which shows the 2nd example of the schematic structure of the multi-inverter motor system which concerns on 2nd Embodiment. The block diagram which shows an example of the structure of the drive system which concerns on 2nd Embodiment. The flowchart which shows an example of the process of the drive system which concerns on 2nd Embodiment. The time change of torque from the transient state to the steady state of the rotor before and after the pole number conversion when the induction motor according to the second embodiment converts the pole number, and the pole number conversion when the comparative example 2 converts the pole number. The figure which exemplifies the comparison result with the time change of the torque from the transient state to the steady state of the front and rear rotors.

Hereinafter, embodiments of the invention will be described with reference to the drawings. In the following description, substantially the same components and functions are designated by the same reference numerals, and the description is omitted or the description will be given as necessary.

In each embodiment, an induction motor will be used as an example of the induction motor. It should be noted that each embodiment can be applied to other types of induction rotary electric machines such as an induction generator instead of the induction motor.

The induction motor according to each embodiment can be applied to various fields such as electric vehicles, hybrid vehicles, railways, airplanes, mobile devices, robots, and energy saving systems.

(First Embodiment)
In the present embodiment, by controlling the phase of the current supplied to the induction motor, the torque of the induction motor is increased, and the efficiency and power factor of the induction motor are improved.

FIG. 1 is a diagram showing an example of a schematic configuration of the electric motor system 21 according to the present embodiment. In FIG. 1, the induction motor 1 in the electric motor system 21 represents a cross section (diameter cross section) perpendicular to the rotation axis A.

FIG. 2 is a cross-sectional view showing a first example of a schematic configuration of a rotor 3 provided in the induction motor 1 according to the present embodiment. FIG. 2 shows a cross section of the rotor 3 parallel to the rotation axis A.

The electric motor system 21 includes an induction motor 1 and a drive system DS.

The induction motor 1 mainly includes a shaft 2, a rotor 3, a stator 4, and bearings 5a, 5b, 6a, and 6b. The induction motor 1 is further provided with a blanket or the like for covering the stator 4, but is omitted in FIG. 1 for simplification.

The shaft 2 has a rotation shaft A. The shaft 2 is rotatably supported via bearings 5a and 5b, for example, with respect to a blanket or stator 4 (not shown). In the present embodiment, the shaft 2 may be made of a magnetic material or may be made of a non-magnetic material for weight reduction.

The rotor 3 includes a magnet rotor 7, a rotor core 8, and a plurality of rotor coils 9. A conductor may be used instead of the rotor coil 9. In the present embodiment, the magnet rotor 7 will be described as a part of the rotor 3, but the magnet rotor 7 and the rotor 3 may be treated as different members.

The magnet rotor 7 is rotatably supported with respect to the shaft 2 via bearings 6a and 6b. The magnet rotor 7 includes a central portion 10 and a plurality of permanent magnets 11.

The central portion 10 is a rotor core made of a magnetic material. The central portion 10 is arranged on the outer peripheral side of the shaft 2. The central portion 10 may be referred to as a magnet rotor core.

The permanent magnet 11 is arranged so as to cover the outer periphery of the central portion 10. In FIG. 1, eight permanent magnets 11 are arranged along the circumferential direction on the circumferential portion of the cross section of the central portion 10. Of the two permanent magnets 11 adjacent to each other, when the inner peripheral surface (inner diameter) side of one permanent magnet 11 is the north pole and the outer peripheral surface (outer diameter) side is the south pole, the inner peripheral surface side of the other permanent magnet 11 Is the S pole, and the outer peripheral surface side is the N pole. In this way, the polarities of the plurality of permanent magnets 11 arranged on the outer peripheral surface of the central portion 10 are staggered. In FIG. 1, the number of permanent magnets 11 is eight, but this number can be changed as appropriate.

The rotor core 8 is arranged on the outer peripheral side of the magnet rotor 7. The rotor core 8 has a cylindrical shape and is fixedly supported with respect to the shaft 8. The rotor core 8 may have a cage shape, for example. The rotor core 8 may be referred to as a winding rotor. The rotor core 8 may be made of a non-magnetic material for weight reduction.

A plurality of slots are formed on the outer peripheral surface of the rotor core 8, and a rotor coil 9 is provided in each of the plurality of slots.

The stator 4 is arranged on the outer peripheral side of the rotor 3. The stator 4 includes a cylindrical stator core 12 and a plurality of stator coils 13.

A plurality of slots are formed on the inner peripheral surface of the stator core 12, and a stator coil 13 is provided in each of the plurality of slots. The stator core 12 may be made of a non-magnetic material for weight reduction.

In the present embodiment, the magnet rotor 7 is provided with the same number of permanent magnets 11 as the number of poles of the induction motor 1 so that the polarities alternate. The rotor core 8 connected to the shaft 2 rotates with a slip behind the rotating magnetic field generated by the stator 4. The magnet rotor 7 rotates separately from the rotor core 8 in synchronization with the rotating magnetic field generated by the stator 4.

The drive system DS controls the induction motor 1 having the above configuration. Specifically, the drive system DS controls the inverter 14 to pass a current through the stator coil 13 of the stator 4, the central axis of the rotating magnetic field generated by the current flowing through the stator coil 13, and a magnet. The phase of the current is controlled so that the d-axis, which is the direction of the magnetic field generated from the magnetic pole of the rotor 7, is substantially the same. In the drive system DS, the phase of the current is such that the angle difference between the central axis of the rotating magnetic field and the d-axis is within a predetermined allowable range (including the case where the central axis of the rotating magnetic field and the d-axis match). May be controlled.

FIG. 3 is a cross-sectional view showing a second example of the schematic configuration of the rotor 3 provided in the induction motor 1 according to the present embodiment. FIG. 3 shows a cross section of the rotor 3 parallel to the rotation axis A, similar to FIG. 2 above.

The rotor 3 of FIG. 3 has a cylindrical rotor core 8 fixedly supported with respect to the shaft 2 and a cylindrical shape rotatably supported with respect to the rotor core 8 via bearings 6a and 6b. The magnet rotor 7 of the above is provided. The rotor core 8 includes a plurality of rotor coils 9 or conductors on the outer peripheral surface. The rotor core 8 may be, for example, an iron core in which electromagnetic steel plates are laminated. In the rotor 3 having the configuration shown in FIG. 3, since the magnet rotor 7 has a sliding speed that is extremely slow relative to the rotor core 8, it is between the magnet rotor 7 and the rotor core 8. The provided bearings 6a and 6b for the magnet rotor 7 have an advantage that they do not require high characteristics corresponding to high-speed rotation.

FIG. 4 is a conceptual diagram showing an example of the d-axis and the q-axis. FIG. 4 shows a cross section of the magnet rotor 7a perpendicular to the rotation axis A.

In the example of FIG. 4, the magnet rotor 7a includes the first permanent magnet 11a at the first position on the outer peripheral surface of the central portion 10a, and the outer peripheral surface facing the first position in the radial direction. A second permanent magnet 11b is provided at the second position of the.

In the present embodiment, the d-axis is the direction of the magnetic flux generated by the magnetic poles of the magnet rotor 7a. In other words, the d-axis is a radial axis passing through the center of the permanent magnet 11a from the rotation axis A of the magnet rotor 7A.

The q-axis is a direction that is magnetically orthogonal to the d-axis. In other words, the q-axis is a radial axis that passes between the rotation axis A of the magnet rotor 7a and the first permanent magnet 11a and the second permanent magnet 11b.

FIG. 5 is a block diagram showing an example of the configuration of the drive system DS of the induction motor 1 according to the present embodiment.

The drive system DS includes a control unit 15, a DC power supply 16, an inverter 14, a conversion unit 17, a command unit 18, and a rotation angle (position) of a rotor 3 or a rotor core 8 directly connected to the rotor 3. An angle (position) sensor 19a for detecting the above, an angle (position) sensor 19b for detecting the rotation angle (position) of the magnet rotor 7, and a torque sensor 20 for detecting the torque of the magnet rotor 7 are provided.

At least two of the control unit 15, the conversion unit 17, and the command unit 18 may be realized by a control circuit. In this case, the control circuit may realize the function as at least two of the control unit 15, the conversion unit 17, and the command unit 18 by executing the control program stored in the memory.
Further, instead of using the angle sensor 19b of the magnet rotor 7, the angle sensor 19b of the magnet rotor 7 may be omitted by using, for example, the following first and second methods.
The first method that can be used in place of the angle sensor 19b of the magnet rotor 7 is a method of detecting the magnetic flux of the magnetic pole by a Hall element, which is a simple magnetic pole sensor technique used in the brushless magnet electric motor.
A second method that can be used in place of the angle sensor 19b of the magnet rotor 7 is to detect the magnetic pole position of the magnet using the induced voltage generated by the magnet in the stator coil during rotation as a sensorless control of a general magnet motor. How to do it.

The control unit 15 acquires a command value related to the current phase (for example, a value indicating one of 0 degrees to 360 degrees) from the command unit 18, and the rotor 3 or the rotor from the angle sensor 19a provided in the induction motor 1. The rotation angle of the rotor core 8 directly connected to 3 is acquired, and the d-axis actual measurement value and the q-axis actual measurement value obtained by converting the output of the inverter 14 by the conversion unit 17 are acquired by feedback. In addition, instead of the rotation angle, the rotation speed or the position information of the rotor 3 may be used.

The control unit 15 has a d-axis command corresponding to the command value based on the command value, the d-axis measured value, the q-axis measured value, the rotation angle of the rotor 3 or the rotor core 8, and the rotation speed calculated from the rotation angle. A value and a q-axis command value are generated, and the generated d-axis command value and the q-axis command value are provided to the inverter 14.

The inverter 14 converts the current supplied from the DC power supply 16 (for example, the rated current) into AC U-phase current, V-phase current, and W-phase current based on the d-axis command value and the q-axis command value, and converts the current into U-phase. A current, a V-phase current, and a W-phase current are supplied to the induction motor 1.

The inverter 14 switches a plurality of power switches based on, for example, the d-axis command value and the q-axis command value, and performs DC-AC conversion.

The conversion unit 17 acquires the U-phase current measured value, the V-phase current measured value, the W-phase current measured value, and the rotation angle of the rotor 3 or the rotor core 8 measured by the angle sensor 19a, and this U-phase current measured. The value, the V-phase current measured value, and the W-phase current measured value are converted into a d-axis measured value and a q-axis measured value, and the d-axis measured value and the q-axis measured value are provided to the control unit 15 for feedback control.

The conversion unit 17 acquires, for example, a U-phase current measured value, a V-phase current measured value, and a W-phase current measured value measured by a current sensor provided in the inverter 14.

First, the command unit 18 changes the command value regarding the current phase provided to the control unit 15 from 0 degrees to 360 degrees, and causes the torque sensor 20 to correspond to each command value and generate torque generated by the magnet rotor 7. get. The relationship between the current phase and the torque obtained as a result will be described later with reference to FIG.
Further, the command unit 18 processes a signal indicating the rotation angle of the magnet rotor 7 acquired from the angle sensor 19b of the magnet rotor 7 as information on the position (d-axis) of the magnetic pole of the magnet rotor 7 at that moment. ..

Next, the command unit 18 determines, for example, the d-axis position obtained from the rotation angle measured by the magnet rotor 7 and / or the current phase obtained by measurement or magnetic field analysis and the torque of the magnet rotor 7. Based on the relationship, the current phase at which the torque becomes almost zero is obtained, the current phase at which the torque generated by the magnet rotor 7 becomes almost zero is determined as a command value, and the determined command value is provided to the control unit 15. .. The command unit 18 may determine the current phase in which the torque generated by the magnet rotor 7 is within a predetermined torque allowable range (including zero) as a command value. Alternatively, the command unit 18 obtains the position of the d-axis from the rotation angle measured by the angle sensor 19b of the magnet rotor 7, and has the central axis of the rotating magnetic field generated by the current flowing through the stator coil 13 and the magnet rotor. The phase of the current may be determined so that the d-axis, which is the direction of the magnetic field generated from the magnetic pole of 7, is substantially the same.

The command unit 18 may acquire the relationship between the current phase and the torque from the result of the magnetic field analysis. In this case, table data including the relationship between the current phase and the torque value obtained by the magnetic field analysis is generated, and the generated table data is stored in a memory or the like as control program data. When actually driving the induction motor 1, the control circuit functioning as the command unit 18 of the drive system DS reads out the table data of the control program stored in the memory, and the torque of the magnet rotor 7 is within the allowable range. The current phase is determined so as to be. Then, the command unit 18 provides the control unit 15 with a command value corresponding to the determined current phase. As a result, the inverter 16 supplies the current of the current phase determined by the command unit 18 to the induction motor 1, and the induction motor 1 is driven by the torque of the magnet rotor 7 within the permissible range.

FIG. 6 is a flowchart showing an example of processing of the drive system DS according to the present embodiment.

In step S601, first, the command unit 18 provides the control unit 15 with the command value of the current phase being sequentially changed from 0 ° to 360 °. Secondly, the command unit 18 has a current phase in which the torque generated by the magnet rotor 7 becomes almost zero, or the central axis of the rotating magnetic field generated by the current flowing through the stator coil 13 and the magnet rotor 7. A current phase that substantially coincides with the d-axis is provided to the control unit 15 as a command value. The processing of the command unit 18 will be described later with reference to FIG. 7.

In step S602, the control unit 15 is calculated from a command value, for example, a d-axis measured value obtained by converting a three-phase current measured by a current sensor in the inverter 14 into two components, a q-axis measured value, a rotation angle, and a rotation angle. The next d-axis command value and q-axis command value are determined based on the rotation speed, and the determined d-axis command value and q-axis command value are provided to the inverter 14.

In step S603, the inverter 14 uses the DC current supplied from the DC power supply 16 as the AC U-phase current, V-phase current, and W-phase based on the d-axis command value and the q-axis command value acquired from the control unit 15. Convert to electric current.

In step S604, the inverter 14 supplies AC U-phase current, V-phase current, and W-phase current to the induction motor 1 to drive the induction motor 1.

In step S605, the angle sensor 19a measures the rotation angle of the rotor 3 or the rotor core 8 and provides the rotation angle to the control unit 15 and the conversion unit 17. The angle sensor 19b of the magnet rotor 7 measures the rotation angle of the magnet rotor 7 and provides the rotation angle of the magnet rotor 7 to the command unit 18. The torque sensor 20 measures the torque generated in the magnet rotor 7 and supplies this torque to the command unit 18. The conversion unit 17 acquires the measured value of the U-phase current, the measured value of the V-phase current, and the actual value of the W-phase current output from the inverter 14, and the rotor 3 or the rotor core 8 measured by the angle sensor 19a. The rotation angle of is obtained, and these U-phase current measured values, V-phase current measured values, and W-phase current measured values are converted into d-axis measured values and q-axis measured values, and the d-axis measured values and q-axis measured values are converted. It is provided to the control unit 15.

In step S606, the drive system DS determines whether or not to terminate the drive of the induction motor 1.

If the drive of the induction motor 1 is not terminated, the process returns to step S601.
When the drive of the induction motor 1 is terminated, the process is terminated.

In FIG. 6, the relationship between the phase of the current flowing through the stator coil 13 and the torque generated by the magnet rotor 7 is obtained by measurement. However, as described above, the phase of the current and the torque The relationship may be determined by magnetic field analysis. The process in which the drive system DS drives the induction motor 1 while controlling the torque of the magnet rotor 7 using the result of this magnetic field analysis will be specifically described below.

When the relationship between the current phase in the induction motor 1 and the torque of the magnet rotor 7 is acquired by magnetic field analysis, table data showing the relationship between the current phase and torque is generated, and this table data is stored in memory as control program data. Stored in. As a result, when a control circuit such as a processor executes a control program, the control circuit can read table data from the memory. After the drive of the induction motor 1 is started, the command unit 18 determines the d-axis position that can be determined by the rotation angle (position) signal of the magnet rotor 7 and / or the torque of the magnet rotor 7 based on the read table data. Determines the current phase so that is within the permissible range, and provides the control unit 15 with a command value (control signal) indicating the determined current phase. In this way, the torque sensor 20 can be deleted when the result of the magnetic field analysis is used.

The control unit 15 is based on the d-axis actual measurement value, the q-axis actual measurement value, the rotation speed calculated from the rotation angle of the rotor 3 or the rotor core 8, and the slip frequency calculated from the drive power supply frequency obtained from the conversion unit 17. The d-axis command value and the q-axis command value corresponding to the torque of the magnet rotor 7 to be controlled are generated, and the d-axis command value and the q-axis command value are provided to the inverter 14. The control executed by the control unit 15 is slip frequency control.

FIG. 7 is a flowchart showing an example of the current phase determination process according to the present embodiment.

In step S701, the command unit 18 provides the command value of the current phase to the control unit 15.

In step S702, the command unit 18 acquires the position of the magnet magnetic pole by the angle sensor 19b of the magnet rotor 7 and the torque of the magnet rotor 7 corresponding to the command value from the torque sensor 20.

In step S703, the command unit 18 stores the relationship between the current phase and the torque in, for example, a memory.

In step S704, the command unit 18 determines whether or not the sequential change of the command value is completed, in other words, whether or not the command value is sequentially output between the current phases of 0 ° and 360 °.

If the sequential change of the command value is not completed, in step S705, the command unit 18 changes the command value indicating the current phase. Then, the process returns to step S701.

When the sequential change of the command value is completed, in step S706, the command unit 18 is generated by an appropriate current phase in which the torque generated by the magnet rotor 7 becomes almost zero, or by the current flowing through the stator coil 13. A command value indicating a current phase in which the central axis of the rotating magnetic field and the d-axis of the magnet rotor 7 substantially coincide with each other is determined.

In step S707, the command unit 18 provides the command value of the determined current phase to the control unit 15.

In the following, the induction motor 1 according to the present embodiment is obtained by comparing the analysis result regarding the induction motor 1 according to the present embodiment with the analysis result regarding the electric motor 1 of Comparative Example 1 in which the permanent magnet 11 is replaced with air. Explain the effect.

The induction motor 1 is, for example, a permanent magnet combined induction motor having a double rotor structure in which a cage-shaped rotor core 8 and a magnet rotor 7 are provided on the same rotating shaft A. The rotor core 8 is mechanically coupled to the shaft 2. The rotor core 8 rotates with a slip from the rotating magnetic field. The magnet rotor 7 is provided on the shaft 2 via bearings 6a and 6b, and can rotate freely. The magnet rotor 7 rotates in synchronization with the rotating magnetic field. In the induction motor 1 having such a configuration, the magnetic flux of the permanent magnet 11 and the magnetic flux of the rotating magnetic field of the stator 4 are combined and strengthened, and the exciting magnetic flux is increased. As a result, torque is increased and efficiency is also improved.

Table 1 is an example of the characteristics (analysis conditions) of the induction motor 1 according to the present embodiment used for magnetic field analysis.

In the induction motor 1 according to the present embodiment, the permanent magnet 11 has 8 poles and has symmetry. Therefore, magnetic field analysis is performed on the semicircular model using the periodic boundary conditions.

The slip of the induction motor 1 according to the present embodiment is set to 0.05 for analysis.

On the other hand, in the electric motor of Comparative Example 1, as described above, the permanent magnet 11 of the magnet rotor 7 is used as air, and the permanent magnet 11 is not used in combination. Other analysis conditions for the electric motor of Comparative Example 1 are the same as those in Table 1 above.

FIG. 8 is a graph showing an example of the relationship between the current phase of the induction motor 1 and the torque of the magnet rotor 7 obtained by the magnetic field analysis. FIG. 8 shows the torque-current phase characteristic at the rated current.

In FIG. 8, the current phase is changed from 0 ° to 360 ° in 5 ° increments. In the current phase where the torque is 0 Nm, the q-axis current is small and the d-axis current mainly flows. In order for the magnetic pole center of the permanent magnet 11 of the magnet rotor 7 to substantially coincide with the center of the rotating magnetic field generated by the stator 4, and the magnet rotor 7 to be in a state of being entangled in synchronization with the rotating magnetic field, the magnet is rotated. A current phase in which the torque of the child 7 becomes 0 Nm may be applied.

From the analysis result of FIG. 8, the current phase of the induction motor 1 according to the present embodiment is, for example, between about 180 ° and about 230 °. More specifically, the current phase of the induction motor 1 is set to, for example, about 215 °.

Further, in FIG. 8, the current phase in which the torque of the magnet rotor 7 becomes negative may act as a brake for the rotation of the rotor 3, but the current phase in which the torque of the magnet rotor 7 becomes positive is determined. It does not act as a brake for the rotation of the rotor 3. Therefore, for example, a current phase between about 230 ° and about 360 ° at which the torque of the magnet rotor 7 becomes positive may be applied.

FIG. 9 is a graph showing an example of a fundamental wave of the gap magnetic flux density on the rotor core 8 in a state where the slip at the rated current is 0.05 with respect to the induction motor 1 and Comparative Example 1 according to the present embodiment. FIG. 9 shows the relationship between the electric angle and the magnetic flux density.

In the induction motor 1 according to the present embodiment, since the permanent magnet 11 is used in combination, the magnetic flux of the permanent magnet 11 is superposed on the exciting magnetic flux generated by driving the induction motor 1, and the total gap magnetic flux density is compared with Comparative Example 1. It will be higher than the case of. The amplitude of the fundamental wave of the induction motor 1 according to the present embodiment and the amplitude of the fundamental wave of Comparative Example 1 are 1.18T and 1.06T, respectively. As described above, the amplitude of the fundamental wave of the gap magnetic flux density of the induction motor 1 in which the permanent magnet 11 is used together increases about 1.1 times as much as the amplitude of the fundamental wave of the gap magnetic flux density of Comparative Example 1.

FIG. 10 is a graph showing an example of a time change of torque of the induction motor 1 according to the present embodiment from a transient state to a steady state.

Further, FIG. 11 is a graph showing an example of a time change of torque from the transition state to the steady state of Comparative Example 1.

The horizontal axis of FIGS. 10 and 11 represents time, and the vertical axis represents torque. Further, FIGS. 10 and 11 show torque characteristics at an operating point with a slip of 0.05 at a rated current, respectively.

The torque of the induction motor 1 according to the present embodiment shown in FIG. 10 is 56.6 Nm on average in a steady state.

On the other hand, the torque of Comparative Example 1 shown in FIG. 11 is 41.2 N · m on average in a steady state.

As described above, in the induction motor 1 according to the present embodiment, by using the permanent magnet 11 together, the torque is increased by 15.4 Nm and the rated current is increased as compared with Comparative Example 1 in which the permanent magnet 11 is not used together. It is possible to obtain about 1.4 times the torque while the current is supplied.

Table 2 shows the efficiency and power factor at the rated current of the induction motor 1 and Comparative Example 1 according to the present embodiment.

When the slip is 0.05, the efficiency of the induction motor 1 of the present embodiment is 83.7%, and the power factor is 0.51.

On the other hand, the efficiency of Comparative Example 1 is 80.2% and the power factor is 0.42.

As described above, in the induction motor 1 according to the present embodiment, by using the permanent magnet 11 together, the efficiency is improved by about 3.5% and the power factor is improved by about 1.2 times as compared with Comparative Example 1. To.

As described above, the induction motor 1 according to the present embodiment is driven by a current phase in which the torque generated by the magnet rotor 7 becomes zero. Alternatively, the induction motor 1 has a current phase in which the torque generated by the magnet rotor 7 becomes positive, in other words, the torque generated by the magnet rotor 7 is in the same direction as the torque generated by the rotor core 8. It is driven by the current phase.

As a result, in the magnet-combined induction motor 1 according to the present embodiment, the torque can be increased, the power factor and efficiency can be improved, and the performance can be improved.

In the induction motor 1 according to the present embodiment, since the magnet rotor 7 is prevented from generating torque in the direction opposite to the rotation direction of the rotor core 8, the rotational drive of the electric motor can be stabilized.

In the induction motor 1 according to the present embodiment, the torque can be increased with a small amount of electric power, the consumption of the electric power stored in the battery can be suppressed, and the energy efficiency can be improved.

(Second Embodiment)
In this embodiment, an electric motor system that uses a plurality of inverters (multi-inverters) to convert the number of poles of a magnet-combined induction motor at high speed according to the rotation speed will be described.

Similarly, for an electric motor in which a magnet is not used in combination, the number of poles can be converted at high speed by using a plurality of inverters.

Moreover, this embodiment may be applied in combination with the said 1st Embodiment. Specifically, in the present embodiment, as in the first embodiment described above, by using a current phase that makes the torque generated by the magnet rotor 7 zero, for example, the torque and efficiency of the induction motor. , Power factor, etc. can be improved.

FIG. 12 is a graph showing an example of the control concept of the induction motor according to the present embodiment. In FIG. 12, the horizontal axis represents the rotation speed and the vertical axis represents the torque.

In the torque-to-speed characteristics of the drive electric motor of a traffic system such as an automobile or a train, the torque is required to be large in the low speed rotation range and small in the high speed rotation range. Further, the multi-pole drive motor has a high torque at low speed rotation, and the small pole drive motor has a small torque at high speed rotation. In the present embodiment, when the rotation speed is equal to or less than the threshold T, the number of poles of the induction motor such as 8 poles is increased, and when the rotation speed exceeds the threshold T, the number of poles of the induction motor such as 4 poles is increased. The number is reduced, and performance improvements such as energy saving of the induction motor are realized.

In the present embodiment, in the low speed rotation range where the rotation speed is equal to or less than the threshold T, the number of poles of the stator 4 and the number of poles of the magnet rotor 7 are made the same (synchronous mode), and the rotation speed exceeds the threshold T. In the region, the number of poles of the stator 4 and the number of poles of the magnet rotor 7 are different (for example, the number of poles of the stator 4 is less than the number of poles of the magnet rotor 7) (asynchronous mode).

In the present embodiment, the multi-inverter motor system includes a three-phase inverter and a three-phase coil as one set, and is composed of a plurality of sets. The plurality of three-phase inverters can independently control the current of the corresponding three-phase coil.

The drive system converts the number of poles of the induction motor while driving the induction motor by switching the phase order and the current phase of each inverter, and realizes highly efficient variable speed operation.

FIG. 13 is a diagram showing an example of a schematic configuration of the multi-inverter motor system 211 according to the present embodiment. FIG. 13 illustrates a case where the multi-inverter motor system 211 includes two inverters.

The multi-inverter motor system 211 is composed of two sets of three-phase inverters and three-phase coils.

The multi-inverter motor system 211 includes an induction motor 1A and a drive system DS1.

Twelve slots are formed in the circumferential direction on the inner peripheral surface of the stator 4 of the induction motor 1A. In each of the 12 slots, clockwise, as a stator coil, a1 coil, b2 coil, c1 coil, a2 coil, b1 coil, c2 coil, a1 coil, b2 coil, c1 coil, a2 coil, b1 coil. , C2 coil is arranged.

The two a1 coils are arranged at positions facing each other in the radial direction. Similarly, the two b1 coils, the two c1 coils, the two a2 coils, the two b2 coils, and the two c2 coils are also arranged at positions facing each other in the radial direction.

The other configuration of the induction motor 1A is, for example, the same as that of the induction motor 1 described in the first embodiment.

The drive system DS1 controls the induction motor 1A having the above configuration. Specifically, the drive system DS1 controls the first and second inverters 141 and 142.

The first inverter 141 converts DC current into alternating currents a1 current, b1 current, and c1 current, supplies a1 current to two a1 coils, supplies b1 current to two b1 coils, and c1 current. Is supplied to the two c1 coils. In the present embodiment, the first inverter 141 controls the current phases of the a1 current, the b1 current, and the c1 current.

The second inverter 142 converts the DC current into alternating currents a2 current, b2 current, and c2 current, supplies the a2 current to the two a2 coils, supplies the b2 current to the two b2 coils, and c2 current. Is supplied to the two c2 coils. In the present embodiment, the second inverter 142 controls the current phases of the a2 current, the b2 current, and the c2 current.

FIG. 14 is a diagram showing an example of a schematic configuration of the multi-inverter motor system 212 according to the present embodiment. FIG. 14 illustrates a case where the multi-inverter motor system 212 includes three inverters.

The multi-inverter motor system 212 is composed of three sets of three-phase inverters and three-phase coils.

The multi-inverter motor system 212 includes an induction motor 1B and a drive system DS2.

Eighteen slots are formed in the circumferential direction on the inner peripheral surface of the stator 4 of the induction motor 1B. In each of the 18 slots, clockwise, as a stator coil, a1 coil, a3 coil, b2 coil, c1 coil, c3 coil, a2 coil, b1 coil, b3 coil, c2 coil, a1 coil, a3 coil. , B2 coil, c1 coil, c3 coil, a2 coil, b1 coil, b3 coil, c2 coil are arranged.

The two a1 coils are arranged at positions facing each other in the radial direction. Similarly, the positions of the two b1 coils, the two c1 coils, the two a2 coils, the two b2 coils, the two c2 coils, the two a3 coils, the two b3 coils, and the two c3 coils facing each other in the radial direction. Is placed in.

Other configurations of the induction motor 1B are, for example, the same as those of the induction motor 1 described in the first embodiment.

The drive system DS2 controls the induction motor 1B having the above configuration. Specifically, the drive system DS2 controls the first to third inverters 141, 142, and 143.

The first inverter 141 converts the direct current into a1 current, b1 current, and c1 current, supplies the a1 current to the two a1 coils, and transfers the b1 current to the two b1 coils, as in the case of FIG. It supplies and supplies the c1 current to the two c1 coils. The first inverter 141 controls the current phases of the a1 current, the b1 current, and the c1 current.

The second inverter 142 converts the direct current into a2 current, b2 current, and c2 current, supplies the a2 current to the two a2 coils, and transfers the b2 current to the two b2 coils, as in the case of FIG. Supply and supply the c2 current to the two c2 coils. The second inverter 142 controls the current phases of the a2 current, the b2 current, and the c2 current.

The third inverter 143 converts the DC current into AC currents a3 current, b3 current, and c3 current, supplies the a3 current to the two a3 coils, supplies the b3 current to the two b3 coils, and c3 current. Is supplied to the two c3 coils. In the present embodiment, the third inverter 143 controls the current phases of the a3 current, the b3 current, and the c3 current.

Table 3 shows an example of the relationship between the number of poles and the current phase applied in the above-mentioned multi-inverter motor system 211,212. The current phases applied when there are two sets of three-phase inverters and three-phase coils are listed in the column for two inverters in Table 3. The current phases applied when the three-phase inverter and the three-phase coil are three sets are listed in the column of three inverters in Table 3.

In the multi-inverter motor system 211, when the rotation speed is in the low rotation speed range, the 8-pole stator 4 is applied. In this case, it is assumed that the number of poles of the stator 4 and the number of poles of the magnet rotor 7 are in a synchronized state.

In the multi-inverter motor system 211, the first inverter 141 applies a1 current with a current phase of 0 °, b1 current with a current phase of 120 °, and c1 current with a current phase of 240 ° to the a1 coil and b1 coil, respectively, when eight poles are applied. , C1 coil is supplied.

In the multi-inverter motor system 211, the second inverter 142 applies a2 current with a current phase of 0 °, b2 current with a current phase of 120 °, and c2 current with a current phase of 240 °, respectively, to the a2 coil and b2 coil, respectively. , C2 coil is supplied.

In the multi-inverter motor system 211, the 4-pole stator 4 is applied when the rotation speed is in the high-speed rotation range. In this case, the number of poles of the stator 4 and the number of poles of the magnet rotor 7 are in an asynchronous state, and the number of poles of the stator 4 is smaller than the number of poles of the magnet rotor 7.

In the multi-inverter motor system 211, when four poles are applied, the first inverter 141 applies a1 current with a current phase of 0 °, b1 current with a current phase of 240 °, and c1 current with a current phase of 120 °, respectively, to the a1 coil and b1 coil. , C1 coil is supplied.

In the multi-inverter motor system 211, the second inverter 142 applies a2 current with a current phase of 180 °, b2 current with a current phase of 60 °, and c2 current with a current phase of 300 ° to a2 coil and b2 coil, respectively, when four poles are applied. , C2 coil is supplied.

In this way, the multi-inverter motor system 211 can realize high-speed polarity conversion during driving by changing the current phase.

In the multi-inverter motor system 212, when the rotation speed is in the low rotation speed range, the 8-pole stator 4 is applied. In this case, it is assumed that the number of poles of the stator 4 and the number of poles of the magnet rotor 7 are in a synchronized state.

In the multi-inverter motor system 212, the first inverter 141 applies a1 current with a current phase of 0 °, b1 current with a current phase of 120 °, and c1 current with a current phase of 240 °, respectively, to the a1 coil and b1 coil, respectively. , C1 coil is supplied.

In the multi-inverter motor system 212, the second inverter 142 applies a2 current with a current phase of 40 °, b2 current with a current phase of 160 °, and c2 current with a current phase of 280 ° to the a2 coil and b2 coil, respectively, when eight poles are applied. , C2 coil is supplied.

In the multi-inverter motor system 212, the third inverter 143 applies a3 current with a current phase of 80 °, b3 current with a current phase of 200 °, and c3 current with a current phase of 320 °, respectively, to the a3 coil and b3 coil, respectively. , C3 coil is supplied.

In the multi-inverter motor system 212, the 4-pole stator 4 is applied when the rotation speed is in the high-speed rotation range. In this case, the number of poles of the stator 4 and the number of poles of the magnet rotor 7 are in an asynchronous state, and the number of poles of the stator 4 is smaller than the number of poles of the magnet rotor 7.

In the multi-inverter motor system 212, the first inverter 141 applies a1 current with a current phase of 0 °, b1 current with a current phase of 240 °, and c1 current with a current phase of 120 ° to the a1 coil and b1 coil, respectively, when four poles are applied. , C1 coil is supplied.

In the multi-inverter motor system 212, the second inverter 142 applies a2 current with a current phase of 200 °, b2 current with a current phase of 80 °, and c2 current with a current phase of 320 ° to the a2 coil and b2 coil, respectively, when four poles are applied. , C2 coil is supplied.

In the multi-inverter motor system 212, the third inverter 143 applies a3 current with a current phase of 40 °, b3 current with a current phase of 280 °, and c3 current with a current phase of 160 ° to the a3 coil and b3 coil, respectively, when four poles are applied. , C3 coil is supplied.

As described above, the multi-inverter motor system 212 can realize high-speed polarity conversion by changing the current phase.

FIG. 15 is a block diagram showing an example of the configuration of the drive system DS1 according to the present embodiment.

In FIG. 15, the drive system DS1 including two inverters 141 and 142 will be described as an example, but the drive system DS2 including three or more inverters 141, 142 and 143 also has inverters as the number of inverters increases. The same configuration can be applied by adding a conversion unit and a control unit corresponding to the above.

The angle sensor 19a measures the rotation angle of the rotor 3 or the rotor core 8 and provides the measured rotation angle to the first control unit 151, the second control unit 152, and the command unit 18A. A rotation speed sensor may be used instead of the angle sensor 19a.

The designation unit 18A acquires the rotation angle of the rotor 3 or the rotor core 8 from the angle sensor 19a, and calculates the rotation speed based on the rotation angle and the time measured by a timer (not shown).

The designation unit 18A determines that the rotation speed is in the low speed rotation range when the rotation speed is equal to or less than the threshold value T, and determines that the rotation speed is in the high speed rotation range when the rotation speed exceeds the threshold value T.

Using the relationship shown in Table 3 above, the designation unit 18 sets the a1 command value indicating that the current phase of the a1 current is 0 ° and the current phase of the b1 current to 120 ° in the low speed rotation range. The b1 command value indicating that and the c1 command value indicating that the current phase of the c1 current is set to 240 ° are determined, and the determined a1 command value, b1 command value, and c1 command value are provided to the first control unit 151. ..

Using the relationship shown in Table 3 above, the designation unit 18 sets the a2 command value indicating that the current phase of the a2 current is 0 ° and the current phase of the b2 current to 120 ° in the low speed rotation range. The b2 command value indicating that the c2 command value and the c2 command value indicating that the current phase of the c2 current is set to 240 ° are determined, and the determined a2 command value, b2 command value, and c2 command value are provided to the second control unit 152. ..

On the other hand, the designation unit 18 uses the relationship shown in Table 3 above to set the a1 command value indicating that the current phase of the a1 current is 0 ° and the current phase of the b1 current to 240 ° in the high-speed rotation range. The b1 command value indicating that the current is to be set and the c1 command value indicating that the current phase of the c1 current is set to 120 ° are determined, and the determined a1 command value, b1 command value, and c1 command value are sent to the first control unit 151. provide.

Using the relationship shown in Table 3 above, the designation unit 18 sets the a2 command value indicating that the current phase of the a2 current is 180 ° and the current phase of the b2 current to 60 ° in the high-speed rotation range. The b2 command value indicating that and the c2 command value indicating that the current phase of the c2 current is set to 300 ° are determined, and the determined a2 command value, b2 command value, and c2 command value are provided to the second control unit 152. ..

The first control unit 151 is based on the a1 command value, the b1 command value, the c1 command value, the first d-axis measured value, the first q-axis measured value, the rotation angle, and the rotation speed calculated from the rotation angle. , The first d-axis command value and the first q-axis command value are generated, and the generated first d-axis command value and the first q-axis command value are provided to the first inverter 14.

The second control unit 152 is based on the a2 command value, the b2 command value, the c2 command value, the second d-axis measured value, the second q-axis measured value, the rotation angle, and the rotation speed calculated from the rotation angle. , A second d-axis command value and a second q-axis command value are generated, and the generated second d-axis command value and the second q-axis command value are provided to the second inverter 14.

The first inverter 141 converts the DC current supplied from the DC power supply 16 into AC a1 current, b1 current, and c1 current based on the first d-axis command value and the first q-axis command value. The a1 current, b1 current, and c1 current are supplied to the induction motor 1A.

The second inverter 142 converts the DC current supplied from the DC power supply 16 into AC a2 current, b2 current, and c2 current based on the second d-axis command value and the second q-axis command value. The a2 current, b2 current, and c2 current are supplied to the induction motor 1A.

The first conversion unit 171 acquires the a1 current measured value, the b1 current measured value, and the c1 current measured value for Fordback control, and the rotation angle of the rotor 3 or the rotor core 8 measured by the angle sensor 19a. Is obtained, and the a1 current measured value, the b1 current measured value, and the c1 current measured value are converted into the first d-axis measured value and the first q-axis measured value, and the first d-axis measured value and the first The q-axis measured value of the above is provided to the first control unit 151.

The second conversion unit 172 acquires the a2 current measured value, the b2 current measured value, and the c2 current measured value for Fordback control, and obtains the angle of the rotor 3 or the rotor core 8 measured by the angle sensor 19a. The a2 current measured value, the b2 current measured value, and the c2 current measured value are converted into the second d-axis measured value and the second q-axis measured value, and the second d-axis measured value and the second d-axis measured value are obtained. The q-axis measured value is provided to the second control unit 152.

FIG. 16 is a flowchart showing an example of processing of the drive system DS1 according to the present embodiment. The drive system DS2 including three or more inverters can also perform the same processing as in FIG. 16 with appropriate changes.

In step S1601, the command unit 18A calculates the rotation speed based on the rotation angle and the time acquired from the angle sensor 19a. The command unit 18A determines whether it is a low speed rotation range or a high speed rotation range based on the rotation speed, and a1 command value, b1 command value, c1 command value, a2 command indicating the current phase corresponding to the judgment result based on Table 3. The value, the b2 command value, and the c2 command value are determined. The command unit 18A provides the determined a1 command value, b1 command value, and c1 command value to the first control unit 151, and delivers the determined a2 command value, b2 command value, and c2 command value to the second control unit 152. provide.

In step S1602, the first control unit 151 rotates the rotation calculated from the a1 command value, the b1 command value, the c1 command value, the first d-axis measured value, the first q-axis measured value, the rotation angle, and the rotation angle. The first d-axis command value and the first q-axis command value are determined based on the speed, and the determined first d-axis command value and the first q-axis command value are provided to the first inverter 141. .. The second control unit 152 is based on the a2 command value, the b2 command value, the c2 command value, the second d-axis measured value, the second q-axis measured value, the rotation angle, and the rotation speed calculated from the rotation angle. , The second d-axis command value and the second q-axis command value are determined, and the determined second d-axis command value and the second q-axis command value are provided to the second inverter 142.

In step S1603, the first inverter 141 transfers the DC current supplied from the DC power supply 16 based on the first d-axis command value and the first q-axis command value acquired from the first control unit 151. Converts to AC a1 current, b1 current, and c1 current. The second inverter 142 uses the DC current supplied from the DC power supply 16 as the AC a2 current based on the second d-axis command value and the second q-axis command value acquired from the second control unit 152. , B2 current, c2 current.

In step S1604, the first inverter 141 supplies AC a1 current, b1 current, and c1 current to the induction electric motor 1, and the second inverter 142 supplies alternating current a2 current, b2 current, and c2 current to the induction electric motor 1. The induction motor 1 is driven by the current supplied to the first and second inverters 141 and 142.

In step S1605, the angle sensor 19a measures the rotation angle of the rotor 3 or the rotor core 8, and measures the rotation angle by the first conversion unit 171 and the second conversion unit 172, the command unit 18A, and the first. It is provided to the control unit 151 and the second control unit 152. The first conversion unit 171 acquires the measured value of the a1 current output from the inverter 14, the measured value of the b1 current, and the actual value of the c1 current, and the rotor 3 or the rotor core 8 measured by the angle sensor 19a. The rotation angle of the above is acquired, and these a1 current measured value, b1 current measured value, and c1 current measured value are converted into the first d-axis measured value and the first q-axis measured value, and the first d-axis measured value is obtained. The value and the first q-axis measured value are provided to the first control unit 151. The second conversion unit 172 acquires the measured value of the a2 current, the measured value of the b2 current, and the actual value of the c2 current output from the inverter 14, and the rotor 3 or the rotor core 8 measured by the angle sensor 19a. The rotation angle of is obtained, and these a2 current measured value, b2 current measured value, and c2 current measured value are converted into a second d-axis measured value and a second q-axis measured value, and a second d-axis measured value is obtained. The value and the second q-axis measured value are provided to the second control unit 152.

In step S1606, the drive system DS1 determines whether or not to terminate the drive of the induction motor 1A.

If the drive of the induction motor 1A is not terminated, the process returns to step S1601.
When the drive of the induction motor 1A is terminated, the process is terminated.

In the following, by comparing the torque characteristics of the induction motor 1A according to the present embodiment with the torque characteristics of the electric motor of Comparative Example 2 in which the permanent magnet of the induction motor 1A is replaced with air, the induction motor 1A according to the present embodiment is compared. The effect obtained by is explained.

FIG. 17 shows the time change of the torque of the rotor 3 from the transient state to the steady state before and after the pole number conversion when the induction motor 1A according to the present embodiment converts the pole number, and when the comparative example 2 converts the pole number. It is a figure which illustrates the comparison result with the time change of the torque from the transient state to the steady state of the rotor before and after the pole number conversion of. In the graph included in FIG. 17, the horizontal axis represents time and the vertical axis represents torque.

The torque of the rotor 3 of the induction motor 1A according to the present embodiment is larger than the torque of Comparative Example 2 both before and after the pole number conversion of the stator 4.

Specifically, in the low-speed rotation range, the torque of the rotor 3 of the induction motor 1A according to the present embodiment averages 82.701 Nm in the steady state, and the torque of Comparative Example 2 averages 56 in the steady state. It is .183 Nm, and the torque of the rotor 3 of the induction motor 1A according to the present embodiment is improved by about 1.5 from the torque of Comparative Example 2.

In the high-speed rotation range where the number of poles of the stator 4 decreases, the torque of the rotor 3 of the induction motor 1A according to the present embodiment averages 20.330 Nm in a steady state, and the torque of Comparative Example 2 is steady. The average is 17.993 Nm in the state, and the torque of the rotor 3 of the induction motor 1A according to the present embodiment is about 1.13 times higher than the torque of Comparative Example 2.

In the present embodiment, the conversion of the number of poles of the rotating magnetic field of the stator 4 can be realized by switching the connection and phase of each stator coil 13 in a switching circuit using a power element, but it is fixed. The pole number conversion of the child 4 may be realized by another method. An excellent method includes conversion of the number of poles of the rotating magnetic field of the stator 4 by a plurality of inverters (multi-inverters) as described in the present embodiment.

For example, the number of poles of the induction motors 1A and 1B may be converted by using a switch circuit. More specifically, an electromagnetic contact switch circuit is provided for each stator coil 13, and the phase is controlled by controlling the presence / absence and timing of energization of each stator coil 13 by turning on / off the switch circuit. The number can be changed, and the number of poles can be changed by adjusting the on / off period. Further, two types of stator coils having different numbers of poles may be provided in the slots of the stator 4, and the two types of stator coils may be used separately.

The features of the induction motors 1A and 1B according to the present embodiment described above will be described.

Permanent magnet motors and induction motors are widely used as variable speed motors. The permanent magnet motor has high torque and high efficiency in the low-speed to medium-speed rotation range, but the efficiency is equal to or less than that of the induction motor in the high-speed rotation range or at a light load (constant rotation). On the other hand, an induction motor may have a smaller torque than a permanent magnet motor in a low speed rotation range and its efficiency may decrease, but it becomes highly efficient in a high speed rotation range and is higher than a permanent magnet motor in a light load or a maximum rotation speed range. Increased efficiency.

In the present embodiment, a magnetic flux is generated in the rotor 3 by an electromagnetic induction action, and a magnetic flux generated by the magnet rotor 7 is superimposed on the magnetic flux generated by the rotor 3. Further, in the present embodiment, the rotating magnetic field is converted into the number of poles by the stator 4 having a plurality of inverters and a plurality of groups of polyphase coils as described in the present embodiment, or the stator 4 is fixed. By switching the connection of the child coil 13 using, for example, an electromagnetic contact switch, or by switching the connection and phase of the stator coil 13 by a switching circuit using a power element, the stator 4 of the induction motors 1A and 1B Converts the number of poles in the rotating magnetic field.

In the present embodiment, the magnet rotor 7 has a certain number of poles, and in the low speed rotation range, the multi-pole rotating magnetic field by the stator coil 13 and the magnetic field of the permanent magnet 11 are synchronized and superposed, and the torque is improved. In the present embodiment, in the high-speed rotation range, the number of poles of the stator 4 is smaller than the number of poles of the magnet rotor 7, the number of magnetic poles of the rotating magnetic field generated by the stator coil 13 and the number of poles of the magnetic field by the permanent magnet 11. The multi-pole rotating magnetic field of the stator coil 13 and the magnetic field of the permanent magnet 11 are not synchronized, and most of the torque generated by the rotor 4 is an induction action of only the rotating magnetic field of the three-phase current. The induced current generated in the rotor coil 9 or the conductor of the rotor core 8 and the torque generated by the rotor core 8 due to the induced current and the exciting magnetic field of the rotating magnetic field.

In the present embodiment described above, the number of poles of the stator 4 and the number of poles of the magnet rotor 7 are the same in the low-speed rotation range, and the rotating magnetic field of the stator coil 13 and the magnetic field of the permanent magnet 11 are synchronized. , High torque of induction motors 1A and 1B is realized.

Further, in the present embodiment, the number of poles of the stator 4 is converted to be small in the high-speed rotation range, and the number of poles of the stator 4 and the number of poles of the magnet rotor 7 are different from each other. The rotating magnetic field generated by the coil 13 and the magnetic field of the permanent magnet 11 become asynchronous. In this case, the influence of the drive voltage (basic frequency component) of the induced voltage generated by the magnetic field of the permanent magnet 11 in the high-speed rotation range is reduced, and the weak magnetic flux control for reducing the permanent magnet magnetic flux for limiting the drive voltage to the upper limit value or less is reduced. Is no longer required, and the current for weakening magnetic flux control is also unnecessary, improving output and efficiency.

Therefore, in the present embodiment, the induction motors 1A and 1B are improved in performance in the entire drive range from low speed to high speed by changing the number of poles of the stator 4 by using a plurality of inverters according to the rotation speed. be able to.

The present invention is not limited to the embodiments described above, and each embodiment can be implemented by deleting, adding, or modifying components. Further, by appropriately combining or exchanging each component of each embodiment, it can be implemented in a further different form. As described above, even if the embodiment is directly different from the embodiment described above, the embodiment having the same purpose as the present invention is described as the embodiment of the present invention, and the description thereof is omitted. There is.

1,1A, 1B ... Induction motor, DS, DS1, DS2 ... Drive system, 2 ... Shaft, A ... Rotor shaft, 3 ... Rotor, 4 ... Stator, 5a, 5b, 6a, 6b ... Bearing, 7 ... Magnet Rotor, 8 ... Rotor core 8, 9 ... Rotor coil, 10 ... Center, 11 ... Permanent magnet 11, 12 ... Stator core, 13 ... Stator coil, 14 ... Inverter, 141 ... First inverter, 142 ... 2nd inverter, 143 ... 3rd inverter, 15 ... Control unit, 151 ... 1st control unit, 152 ... 2nd control unit, 16 ... DC power supply, 17 ... Conversion unit, 171 ... 1st Conversion unit, 172 ... Second conversion unit, 18 ... Command unit, 19a ... Angle sensor, 19b ... Magnet rotor angle sensor, 20 ... Torque sensor, 21 ... Electric motor system, 211,212 ... Multi-inverter motor system.

Claims (6)

Induction rotary electric machine and
A drive system for driving the induction rotary electric machine and
Equipped with
The induction rotary electric machine
With the shaft
A cylindrical magnet rotor arranged on the outer peripheral side of the shaft and rotatably supported with respect to the shaft, and a cylindrical shape arranged on the outer peripheral side of the magnet rotor and fixedly supported with respect to the shaft. Rotor core, and a rotor including a plurality of rotor coils or conductors provided on the outer peripheral surface of the rotor core.
A stator arranged on the outer peripheral side of the rotor and having a cylindrical stator core and a plurality of stator coils provided on the inner peripheral surface of the stator core.
Equipped with
In the drive system, the central axis of the rotating magnetic field generated by the currents flowing through the plurality of stator coils and the d-axis which is the direction of the magnetic flux generated by the plurality of magnetic poles of the magnet rotor are substantially aligned with each other. In addition, the phase of the current is controlled.
Rotating electrical system. The drive system controls the phase of the current so that the rotational torque generated by the magnet rotor is substantially zero.
The rotary electric machine system of claim 1. The drive system includes a plurality of inverters, and controls the phase of the current supplied from the plurality of inverters to the plurality of stator coils based on the rotation speed of the rotor to control the phase of the rotating magnetic field. Convert the number of poles,
The rotary electric system according to claim 1 or 2. The drive system has a first mode in which the first pole number of the magnetic field generated by the magnet rotor and the second pole number of the rotating magnetic field are synchronized when the rotation speed is equal to or less than a predetermined threshold value. Drives the induction rotary electric machine with, and when the rotation speed is equal to or less than a predetermined threshold value, the induction rotary electric machine is driven in a second mode in which the number of the first pole and the number of the second poles are asynchronous. Let,
The rotary electric system of claim 3. Induction rotary electric machine and
A drive system for driving the induction rotary electric machine and
Equipped with
The induction rotary electric machine
With the shaft
A cylindrical magnet rotor arranged on the outer peripheral side of the shaft and rotatably supported with respect to the shaft, and a cylindrical shape arranged on the outer peripheral side of the magnet rotor and fixedly supported with respect to the shaft. Rotor core, and a rotor including a plurality of rotor coils or conductors provided on the outer peripheral surface of the rotor core.
A stator arranged on the outer peripheral side of the rotor and having a cylindrical stator core and a plurality of stator coils provided on the inner peripheral surface of the stator core.
Equipped with
In the drive system, the phase of the current flowing through the plurality of stator coils is such that the first rotational torque generated by the magnet rotor is in the same direction as the second rotational torque generated by the rotor. To control,
Rotating electrical system. It is a control method for induction rotary electric machines.
The induction rotary electric machine
With the shaft
A cylindrical magnet rotor arranged on the outer peripheral side of the shaft and rotatably supported with respect to the shaft, and a cylindrical shape arranged on the outer peripheral side of the magnet rotor and fixedly supported with respect to the shaft. Rotor core, and a rotor including a plurality of rotor coils or conductors provided on the outer peripheral surface of the rotor core.
A stator arranged on the outer peripheral side of the rotor and having a cylindrical stator core and a plurality of stator coils provided on the inner peripheral surface of the stator core.
Equipped with
The control method is
To pass an electric current through the stator coils of the plurality of stators,
Controlling the phase of the current so that the central axis of the rotating magnetic field generated by the current and the d-axis, which is the direction of the magnetic flux generated by the plurality of magnetic poles of the magnet rotor, substantially coincide with each other.
Equipped with
Control method.

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