JP4340632B2 - Permanent magnet type rotating electric machine and compressor using the same - Google Patents

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 and a compressor using the permanent magnet type rotating machine which are improved in the prevention of overcurrent trip in the inverter drive.

In order to solve the above problems, the permanent magnet rotating electrical machine of the present invention, a stator armature windings are provided in the slot, neodymium permanent magnets periphery of character shape permanent magnet insertion holes of the rotor core A permanent magnet type rotating electrical machine having a plurality of rotors arranged in the vicinity of the surface, wherein the rotor is rotatably supported by a rotating shaft through a gap inside the stator. A V-shaped cut portion is provided between the permanent magnets on the outer periphery, a plurality of slits are provided at irregular intervals outside the permanent magnet insertion hole of the rotor core, and the plurality of slits are symmetrical with respect to the magnetic pole center line. And the plurality of slits are inclined so that the extension lines of the side surfaces of the slits intersect at one point on the magnetic pole center line on the stator side. In addition, a compressor according to the present invention is characterized in that the above-described permanent magnet type rotating electrical machine is mounted.

  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 the drawings . 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. In the rotor 3, a single-letter-shaped permanent magnet insertion hole 11 is formed in the vicinity of the outer peripheral surface of a rotor core 10 having a shaft (not shown) hole 9, 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 magnetic pole center line . 15a, 15b, 15c and 15d have unequal pitches. Further, the magnetic pole slits 15a, 15b, 15c, the intersection of the extension of each side of the 15d are arranged so as to coincide with a point on the pole center line.

  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.

When a current is supplied to the armature winding 8, the flow of the armature reaction magnetic flux. D-axis magnetic flux direction of the permanent magnet 12, therewith hampered an axis orthogonal with 90 electrical degrees when the q-axis, d-axis reaction magnetic flux pole slits 15, the permanent magnet insertion hole 12 or V-shaped cut 16 As a result, the d-axis reactance Xd becomes small. In contrast, q-axis reaction magnetic flux results hampered pole slits 15 or V-shaped cut 16, q-axis reactance Xq is reduced. In particular, the q-axis reactance Xq is significantly reduced, and both reactances are approximately Xd = Xq.

Further, when providing such a slit, a magnetic field is concentrated on the stator side of the magnetic pole center line, the magnetic flux is converged on the magnetic pole center line of the stator side, the induced voltage generated is sinusoidal and Become.

Comparing the induced voltage waveform provided with the slit according to the embodiment of the present invention shown in FIG. 5 and the induced voltage waveform without the slit shown in FIG. 7 , the embodiment of FIG. 5 is more effective for sine wave formation. It is shown.

FIGS . 6 and 8 show the analysis results of the induced voltage component ratios in FIGS . 5 and 7 . 6 shows an analysis result of the induced voltage composition ratio when the slit shown in FIG. 5 is provided, and FIG. 8 shows an analysis result of the induced voltage composition ratio when there is no slit shown in FIG. is there.

Harmonic distribution closer to the induced voltage slits sine wave as shown in Fig. 5 described above (FIG. 6) is obtained comparing the harmonic distribution without slits as shown in FIG. 7 (8), the waveform distortion factor 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 in this embodiment , 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 phase angle between the current and voltage is reduced. Thus, since the power factor is improved, the control of the inverter is stabilized, and the overcurrent trip of the inverter can be prevented.

FIG. 3 shows an electric compressor according to an embodiment of the present invention, and shows an axial sectional shape. In FIG. 3 , 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 part 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. 4 is 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.

Comparing the operation result in the embodiment 180 degree position sensorless voltage type inverter 180 inverters driving the permanent magnet type rotating electric machine 1 results drove a traditional rotor current according to an example of the present invention. The rotor 3 of the traditional is differs in comparison with FIG. 1 is a case where the outer diameter of the rotor 3 is not provided pole slits in one magnetic pole core 13. Comparing the d- axis reactance Xd and the q-axis reactance Xq, when the conventional Xd and Xq are 1.0 (p.u.) expressed in the unit method, Xd ′ in the embodiment of the present invention is 0.93, Xq. 'Becomes 0.72, both reactances become small, and in particular, the q-axis reactance Xq becomes significantly small.

Permanent position sensor voltage type inverter 180 ° conduction when the operating load factor of the magnet-type rotating electrical machine from 50% to 175% was confirmed whether caused the overcurrent trip. Because reactance is large when the traditional, the phase difference of the induced electromotive force and the applied voltage of the permanent magnet type rotating electrical machine, i.e. the load angle exceeds 60 degrees, the load factor is the position sensorless voltage type inverter exceeds 150% over Stopped due to current 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, and 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 operating 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 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 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 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 (2)

A stator with armature windings in the slots;
A rotor with a plurality of single-character neodymium permanent magnets arranged in the vicinity of the outer peripheral surface in the 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 V-shaped cut portion is provided between the permanent magnets on the outer periphery of the rotor iron core,
Provide a plurality of slits at unequal intervals outside the permanent magnet insertion hole of the rotor core,
The plurality of slits are provided symmetrically with respect to the magnetic pole center line, and the plurality of slits are inclined so that an extension line of a side surface of each slit intersects at one point on the magnetic pole center line on the stator side. Permanent magnet type rotating electric machine.   A compressor equipped with the permanent magnet type rotating electrical machine according to claim 1.

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