JP2006211823A - Permanent magnet type rotary electric machine and compressor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet type rotary electric machine capable of preventing overcurrent tripping down to an overload operation region. <P>SOLUTION: The permanent magnet type rotary electric machine comprises a stator with an armature coil of concentrated winding type provided to enclose a teeth in a plurality of slots formed at a stator core. The rotor in which a permanent magnet is arranged in a plurality of permanent magnet insert holes in the rotor core is rotatably supported by the rotating shaft on the inner periphery of the stator through a gap. A plurality of magnetic pole slits are formed at the magnetic pole core part outside the permanent magnet insert hole of the rotor core, so that overcurrent tripping is prevented down to an overload operation region of an inverter. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for providing a permanent magnet type rotating electrical machine including a permanent magnet for a field in a rotor.

  There is a permanent magnet type rotating electrical machine disclosed in Patent Document 1.

JP 2004-7875 A

  In Patent Document 1, a recess is formed between the outer peripheral surfaces of the rotor core so that the electrical angle of the magnetic pole angle of the rotor core is within a predetermined range, and a slit is provided in the magnetic pole portion of the rotor core. So we are trying to solve the noise problem.

  By the way, recently, a voltage type inverter of 180 degree conduction has been adopted as an inverter due to the problem of noise reduction. When this motor is driven by a 180 degree energized voltage type inverter, there is a problem that the motor current becomes unstable in the overload operation region and the inverter generates an overcurrent trip.

  An object of the present invention is to provide a permanent magnet type rotating electrical machine which is improved in the drive of an inverter, compared with the conventional one, with respect to prevention of an overcurrent trip.

  In order to solve the above problems, the permanent magnet type rotating electric machine of the present invention has a stator in which concentrated armature windings are provided so as to surround teeth in a plurality of slots formed in the stator core. A permanent magnet type rotating electrical machine in which a rotor having permanent magnets arranged in a plurality of permanent magnet insertion holes in a rotor core is rotatably supported by a rotating shaft through a gap on the inner periphery of the stator is 180 degrees. In a 180-degree inverter-driven permanent magnet type rotating electrical machine driven by an inverter, the outer diameter of the rotor core is set to a plurality, and the space between the permanent magnet insertion holes is cut into a substantially V shape so that the magnetic poles above the permanent magnet insertion holes A plurality of magnetic pole slits are formed in the iron core.

  In the permanent magnet type rotating electrical machine, a plurality of magnetic pole slits are formed in the magnetic pole core part above the permanent magnet insertion hole and the magnetic pole slits are inclined.

  In the permanent magnet type rotating electrical machine, the magnetic pole slits are arranged at unequal intervals.

  In the permanent magnet type rotating electrical machine, the extension lines of the side surfaces of the magnetic pole slits intersect each other in the vicinity of the magnetic pole center line on the stator side.

  The permanent magnet type rotating electrical machine is provided with a plurality of magnetic pole slits symmetrically with respect to the magnetic pole center line.

  The permanent magnet type rotating electrical machine has an end portion of the permanent magnet insertion hole set to an arc.

  In the permanent magnet type rotating electrical machine, the angle forming the minimum gap of the rotor core is set to approximately 2π / 3 in electrical angle.

  The permanent magnet type rotating electrical machine is a permanent magnet formed in a single letter shape.

  The permanent magnet type rotating electrical machine is mounted on a compressor.

  The present invention has a stator in which concentrated winding armature winding is provided so as to surround teeth in a plurality of slots formed in the stator core, and a plurality of permanent magnet insertion holes in the rotor core are provided. A 180-degree inverter-driven permanent-magnet-type rotating electrical machine in which a permanent-magnet-type rotating electrical machine in which a rotor having a permanent magnet is rotatably supported by a rotating shaft through a gap on the inner periphery of the stator is driven by a 180-degree inverter In the above, the outer diameter of the rotor core is set to a plurality, the space between the permanent magnet insertion holes is cut into a substantially V shape, a plurality of magnetic pole slits are formed in the magnetic pole core portion above the permanent magnet insertion holes, and the slits are inclined. In addition, the extension line of the side surface of each magnetic pole slit intersects in the vicinity of the magnetic pole center line, so that the armature reaction magnetic flux due to the armature current is reduced, and the induced electromotive force and the motor are applied even in the overload operation region. Fit load angle is an electrical angle of pressure within 45 degrees, control of the inverter is stabilized, is obtained by preventing the overcurrent trip of the inverter.

  As described above, according to the present invention, it is possible to provide a permanent magnet type rotating electrical machine that is improved as compared with the prior art in preventing an overcurrent trip.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. In each figure, the common code | symbol shows the same thing. Also, here, a 4-pole permanent magnet type rotating electrical machine is shown, and the ratio of the number of rotor poles to the number of stator slots is set to 2: 3. Further, the case where the permanent magnet type rotating electrical machine is driven by a 180 degree inverter will be described.

  FIG. 1 shows a radial cross-sectional shape of a 180-degree inverter-driven permanent magnet type rotating electrical machine as an embodiment according to the present invention, and FIG. 2 shows a radial cross-sectional shape and a perspective view of the rotor of FIG.

  In FIG. 1, a 180-degree inverter-driven permanent magnet type rotating electrical machine 1 includes a stator 2 and a rotor 3. The stator 2 includes a stator core 6 including a tooth 4 and a core back 5, and concentrated armature windings 8 (three-phase windings) wound around the teeth 4 in slots 7 between the teeth 4. Of U-phase winding 8a, V-phase winding 8b, and W-phase winding 8c).

  Here, since the 180 degree inverter driven permanent magnet type rotating electrical machine 1 has 4 poles and 6 slots, the slot pitch is 120 degrees in electrical angle. The rotor 3 has a single-letter shaped permanent magnet insertion hole 11 formed in the vicinity of the outer peripheral surface of a rotor core 10 having a shaft (not shown) hole 9 formed therein, and a rare earth neodymium permanent magnet 12 is placed in the permanent magnet insertion hole 11. It is fixed. The iron core on the magnetic flux axis of the permanent magnet 12 becomes the magnetic pole core 13. The pole pieces 14 (14a, 14b) extend in the circumferential direction on the inner diameter side of the teeth 4. A plurality of magnetic pole slits 15 are formed in the magnetic core 13.

  The feature of FIG. 1 is that a plurality of magnetic pole slits 15 are provided in the magnetic core 13 and the shape of the rotor core 10. As shown in the radial cross-sectional shape shown in FIG. 2A and the perspective view shown in FIG. 2B, the rotor 3 has an opening degree of the magnetic pole core 13 of θ1 and an opening degree of the magnetic pole iron core 13 as θ2. When the mechanical angle is 90 degrees and the electrical angle of 180 degrees is θ3, θ1 is set near 120 degrees in electrical angle and θ2 is set near 163 degrees in electrical angle. That is, two types of outer diameters of the rotor core 10 are provided, and two types of gap lengths between the stator 2 and the rotor 3 are provided. Further, the iron core between the permanent magnets 12 is cut into a substantially V-shape (V-shaped cut 16) to suppress a change in magnetic flux at the end of the permanent magnet 12. The outer diameter of the rotor core 10 between the opening θ1 and the opening θ2 may be connected by a straight line.

  The magnetic pole slit 15 (consisting of 15a, 15b, 15c, 15d) is provided in the magnetic core 13, and the magnetic pole slits 15a, 15b and the magnetic pole slits 15c, 15d are arranged symmetrically with respect to the axis OX. The slits 15a, 15b, 15c, 15d have unequal pitches. Further, the intersections of the extension lines of the side surfaces of the magnetic pole slits 15a, 15b, 15c, and 15d are arranged so as to coincide with the point P on the axis OY.

  Since the end portion 17 of the permanent magnet insertion hole 11 is formed in an arc shape, the iron core portion between the side surface of the V-shaped cut 16 and the permanent magnet insertion hole increases, and the magnetic pole iron core 13 is damaged by centrifugal force. It is preventing.

  FIG. 3 shows the flow of the armature reaction magnetic flux when current is supplied to the armature winding 8. When the magnetic flux direction of the permanent magnet 12 is the d-axis and the axis orthogonal to the electrical angle of 90 degrees is the q-axis, the d-axis reaction magnetic fluxes Φd1, Φd2, and Φd3 shown in FIG. As a result of being blocked by the insertion hole 12 or the V-shaped cut 16, the d-axis reactance Xd is reduced. In contrast, q-axis reaction magnetic fluxes Φq1, Φq2, and Φq3 shown in FIG. 3B are blocked by the magnetic pole slit 15 or the V-shaped cut 16, so that the q-axis reactance Xq is reduced. In particular, the q-axis reactance Xq is significantly reduced, and both reactances are approximately Xd = Xq.

  When a slit as shown in FIG. 3A is provided, the magnetic field is concentrated on the magnetic pole center line on the stator side as illustrated by the white frame arrow, and the magnetic flux converges on the magnetic pole center line on the stator side. Therefore, the generated induced voltage is converted into a sine wave.

  Comparing the induced voltage waveform with slits according to the embodiment of the present invention shown in FIG. 8 and the induced voltage waveform without slits shown in FIG. 9, the embodiment of FIG. 8 is more effective for sine wave formation. It is shown.

  FIGS. 9 and 11 show the analysis results of the induced voltage component ratios in FIGS. FIG. 9 shows the analysis result of the induced voltage composition ratio when the slit shown in FIG. 8 is provided, and FIG. 11 shows the analysis result of the induced voltage composition ratio when there is no slit shown in FIG. is there.

  The harmonic distribution (FIG. 9) in which the slit is provided as shown in FIG. 8 and the induced voltage is close to a sine wave (FIG. 9) is compared to the harmonic distribution without the slit (FIG. 11) as shown in FIG. It is almost halved, and it can be said that reducing the harmonic components of the magnetic flux is effective for reducing noise and increasing efficiency.

  Moreover, when the induced voltage approaches a sine wave, the harmonic component decreases and the fundamental wave component increases. In this case, for example, even if the drive current output from the inverter device is the same, a higher harmonic component that does not contribute to torque generation and a larger fundamental wave component can obtain a larger torque.

  From another point of view, if the induced voltage is made closer to a sine wave, the drive current to be supplied to obtain torque can be reduced by the amount of the smaller harmonic component, reducing the overcurrent trip. Is possible.

  By the way, in the case of 120-degree energization inverter drive, it is possible to stably secure the control performance by performing the control based on the induced voltage obtained by measurement in the 60-degree non-energization period.

  However, in the case of a 180-degree conduction inverter, there is no period of 60 degrees that is not energized as in the 120-degree conduction inverter, and it is difficult to measure the induced voltage. It is. When the controllability is lowered, the driving current becomes unstable, and in some cases, an overcurrent trip or the like occurs, which is inconvenient.

  On the other hand, by providing a slit as shown in FIG. 3B, the flow of magnetic flux is blocked, the horizontal axis reactance is reduced, the armature reaction magnetic flux due to the armature current is reduced, and the current and voltage are reduced. Since the phase angle becomes smaller and the power factor is improved, the control of the inverter is stabilized, and the overcurrent trip of the inverter can be prevented.

  FIG. 4 shows an electric compressor according to an embodiment of the present invention, and shows an axial sectional shape. In FIG. 4, the external appearance of the electric compressor 201 is formed by a case. The case includes a cylindrical frame 202, an upper lid 203 on the upper end side, and a lower lid 204 on the lower end side. The frame 202 is a sealed container. In the frame 202, a permanent magnet type rotating electrical machine 1 and a compression element 206 called a scroll compressor are housed.

  The compression element 206 is formed by meshing a spiral wrap 209 standing upright on the end plate 208 of the fixed scroll member 207 and a spiral wrap 212 standing upright on the end plate 211 of the orbiting scroll member 210. A compression operation is performed by rotating the crank rotation shaft 213.

  Of the compression chambers 214 (214a, 214b,...) Formed by the fixed scroll member 207 and the orbiting scroll member 210, the compression chamber located on the outermost side is the scroll members 207 and 210 along with the orbiting motion. The volume gradually decreases. When the compression chambers 214 a and 214 b reach the vicinity of the centers of the scroll members 207 and 210, the compressed gas from the suction pipe 215 in both the compression chambers 214 is discharged from the discharge port 216 communicating with the compression chamber 214.

  The discharged compressed gas passes through gas passages (not shown) provided in the fixed scroll member 207 and the fixed member 217 and reaches the frame 202 below the fixed member 217, and a discharge pipe 218 provided on the side wall of the frame 202. To the outside of the electric compressor 201.

  The permanent magnet type rotating electrical machine 1 constituting the electric compressor 201 is controlled by a separate inverter (not shown) and rotates at a rotation speed suitable for the compression operation. Here, the permanent magnet type rotating electrical machine 1 includes a stator 2 and a rotor 3. A rotating shaft 213 provided in the rotor 3 has a crankshaft on the upper side. An oil hole 221 is formed inside the rotating shaft 213, and the lubricating oil in the oil reservoir 222 at the lower portion of the frame 202 is caused by rotation of the rotating shaft 213 through the oil hole 221 to be a sliding bearing type upper bearing portion 223, It is supplied to the lower bearing portion 24 of the ball bearing type. Reference numeral 225 denotes a terminal which supplies power from the inverter to the permanent magnet type rotating electrical machine 1. Reference numeral 226 denotes a pedestal.

  FIG. 5 shows a connection diagram of the electric compressor and the 180-degree inverter. The electric compressor 201 is supplied with the electric power of the three-phase power supply 301 via the 180-degree inverter 401. The 180-degree inverter 401 is a voltage-type inverter without a position sensor, and includes a rectifier circuit 402, a smoothing circuit 403, a control element 404, and a control circuit 405. The 180-degree inverter is driven by performing a vector operation with a microcomputer in the control circuit 405. The magnetic pole position of the permanent magnet type rotating electrical machine 1 is detected without a sensor, and is operated at a desired rotational speed in accordance with the command.

  FIG. 6 shows the results of operating the 180-degree inverter-driven permanent magnet type rotating electrical machine 1 with the 180-degree energized position sensorless voltage type inverter according to the embodiment of the present invention and the results of operation with the conventional rotor shown in FIG. . The conventional rotor 3 of FIG. 7 differs from that of FIG. 1 in that the rotor 3 has one outer diameter and no magnetic pole slit is provided in the magnetic core 13. Comparing the d-axis reactance Xd and the q-axis reactance Xq described in FIG. 3, when Xd and Xq in the conventional method are 1.0 (p.u.), Xd ′ of the embodiment of the present invention is 0.93 and Xq ′ are 0.72, both reactances are reduced, and in particular, the q-axis reactance Xq is significantly reduced.

  Fig. 6 shows the load factor of the permanent magnet type rotating electrical machine expressed in%, and the horizontal axis shows whether or not the 180 degree energized position sensorless voltage type inverter caused an overcurrent trip when operated from 50% to 175%. Is represented by ○ ×. From FIG. 6, since the reactance is large in the conventional case, the phase difference between the induced electromotive force and the applied voltage of the permanent magnet type rotating electric machine, that is, the load angle exceeds 60 degrees, and the load factor exceeds 150%, the position sensorless voltage type The inverter stopped due to an overcurrent trip. On the other hand, in the case of the embodiment of the present invention, since the reactance is small, the phase difference between the induced electromotive force and the applied voltage of the permanent magnet type rotating electric machine, that is, the load angle is 40 degrees and the load angle is 45 degrees or less, and the load factor is Even if it reached 175%, the position sensorless voltage type inverter continued operation without stopping due to an overcurrent trip.

  In other words, in the embodiment of the present invention, the resistance to overcurrent trip is improved, and the overload resistance can be increased without increasing the current capacity of the control element. Further, when considering an electric compressor, since one electric compressor can be shared up to a large capacity range, there is an effect that a resource saving design can be achieved.

  Examples of the permanent magnet type rotating electrical machine according to the embodiment of the present invention include a permanent magnet type rotating electrical machine used for a compressor such as an air conditioner, a refrigerator, a freezer, or a showcase.

  As described above, according to the embodiment of the present invention, the outer diameter of the rotor core is set to a plurality, and the space between the permanent magnet insertion holes is cut into a substantially V shape, so that the magnetic core part at the upper part of the permanent magnet insertion hole. A plurality of magnetic pole slits are formed at the same time, the slits are inclined, and the extension lines of the side surfaces of the magnetic pole slits intersect each other in the vicinity of the magnetic pole center line, thereby reducing the armature reaction magnetic flux due to the armature current and overloading. Even in the operation range, the load angle, which is the electrical angle between the induced electromotive force and the motor applied voltage, is within 45 degrees, the inverter control is stable, the inverter overcurrent trip is prevented, and the current capacity of the control element is increased without increasing the current capacity. It is possible to provide a permanent magnet type rotating electrical machine capable of increasing the load resistance.

Sectional drawing which shows the radial direction cross-sectional shape of the permanent-magnet-type rotary electric machine by the Example of this invention. The figure which shows the radial cross-sectional shape and perspective view of the rotor of FIG. 1 by the Example of this invention. The figure which shows the flow of the armature reaction magnetic flux of the rotor of FIG. 1 by the Example of this invention. The figure which shows the electric compressor which concerns on the Example of this invention. The figure which shows the connection of the electric compressor which concerns on the Example of this invention, and a 180 degree | times inverter. The figure which shows the presence or absence of the overcurrent trip of the 180 degree | times inverter which concerns on the Example of this invention. The figure which concerns on the conventional rotor. The figure which shows the analysis result of the induced voltage waveform by the Example of this invention. The figure which shows the analysis result of the distribution of the harmonic by the Example of this invention. The figure which shows the analysis result of the induced voltage waveform by the conventional rotor. The figure which shows the analysis result of the distribution of the harmonic by the conventional rotor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Permanent magnet type rotary electric machine, 2 ... Stator, 3 ... Rotor, 4 ... Teeth, 5 ... Core back, 6 ... Stator core, 7 ... Slot, 8 ... Armature winding, 9 ... Shaft hole, 10 DESCRIPTION OF SYMBOLS ... Rotor core, 11 ... Permanent magnet insertion hole, 12 ... Neodymium permanent magnet, 13 ... Magnetic pole core, 14 ... Magnetic pole piece, 15 ... Magnetic pole slit, 16 ... V-shaped cut, 17 ... Arc part, 201 ... Electric compressor, 202 ... Frame, 203 ... Upper lid, 204 ... Lower lid, 206 ... Compression element, 207 ... Fixed scroll member, 208 ... End plate, 209 ... Spiral wrap, 210 ... Orbiting scroll member, 211 ... End plate, 212 ... Spiral Lapping, 213 ... crankshaft, 214 ... compression chamber, 215 ... suction pipe, 216 ... discharge port, 217 ... fixing member, 218 ... projecting pipe, 221 ... oil hole, 222 ... oil retaining part, 223 ... upper bearing part, 224 Lower bearing unit, 225 ... terminal, 226 ... base, 301 ... three-phase power supply, 401 ... 180 ° inverter, 402 ... rectifier circuit, 403 ... smoothing circuit, 404 ... control device, 405 ... control circuit.

Claims (7)

A stator with armature windings in the slots;
A rotor in which a permanent magnet is disposed in a permanent magnet insertion hole of the rotor core;
In the permanent magnet type rotating electrical machine in which the rotor is rotatably supported by a rotating shaft through a gap inside the stator,
A slit is provided outside the permanent magnet insertion hole of the rotor core,
A permanent magnet type rotating electrical machine characterized in that the slits are inclined so that the extension lines of the side surfaces of the slits intersect in the vicinity of the magnetic pole center line on the stator side. In the permanent magnet type rotating electrical machine according to claim 1,
A permanent magnet type rotating electrical machine, wherein a plurality of slits are provided at unequal intervals. In the permanent magnet type rotating electrical machine according to claim 1 or 2,
A permanent magnet type rotating electrical machine, wherein the plurality of slits are provided symmetrically with respect to a magnetic pole center line. In the permanent magnet type rotating electrical machine according to any one of claims 1 to 3,
A permanent magnet type rotating electrical machine characterized in that an end of the permanent magnet insertion hole is set to an arc.   5. The permanent magnet type rotating electrical machine according to claim 1, wherein an angle forming a minimum gap of the rotor core is set to approximately 2π / 3 in electrical angle. In the permanent magnet type rotating electrical machine according to any one of claims 1 to 5,
A permanent magnet type rotating electrical machine, wherein the permanent magnet is formed in a single letter shape. The compressor carrying any one of the permanent-magnet-type rotary electric machines of Claim 1 thru | or 6.

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