JP5334303B2 - Permanent magnet motor, hermetic compressor, and refrigeration cycle apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet motor in which the amount of magnetic flux of a rotor can reliably be set appropriately, stable dynamic characteristics can be obtained, and excellent reliability is ensured, and to provide a sealed compressor and a refrigeration cycle device which ensure excellent reliability by employing the permanent magnet motor. <P>SOLUTION: The permanent magnet motor includes a rotor 12 formed by arraging a first core 12a and a second core 12b along the axial direction of a rotating shaft 13. A plurality of first permanent magnets 43 whose magnetic force changes by magnetization or demagnetization by an exciting current, are accommodated in the first core 12a of the rotor 12. A plurality of second permanent magnets 44 whose magnetic force does not change irrespective of supply of the exciting current, are accommodated in the second core 12b of the rotor 12. Then, the width of each first permanent magnet 43 is made narrower than that of each second permanent magnet 44. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a permanent magnet motor including a stator having windings and a rotor having permanent magnets, a hermetic compressor housing the permanent magnet motor, and a refrigeration cycle apparatus having the hermetic compressor.

  The permanent magnet motor includes a stator having windings and a rotor having permanent magnets. The rotor has an insertion hole for a rotating shaft at the center of a core formed by laminating a large number of circular steel plates, and has a plurality of linear magnet accommodation holes at positions surrounding the insertion hole. These magnet accommodation holes have a depth shape penetrating the core along the axial direction of the rotation shaft, and each accommodates a permanent magnet. Due to the interaction between the magnetic field of these permanent magnets and the magnetic field generated by the stator winding, a rotational force is generated in the rotor.

  As an example of such a permanent magnet motor, a rotor composed of a plurality of cores arranged along the axial direction of the rotation shaft is used, and a low-coercivity permanent magnet is accommodated in one core of the rotor, while the other In which a high coercivity permanent magnet is housed and an excitation current for magnetization or demagnetization is applied to each phase winding of the stator to change the magnetic force of the low coercivity permanent magnet ( For example, Patent Document 1).

JP-A-2005-304204

  In the permanent magnet motor described in Patent Document 1, the magnetic force of a low-coercivity permanent magnet can be changed by supplying an excitation current for magnetization or demagnetization to each phase winding. The force is unstable, it is difficult to set the amount of magnetic flux of the rotor to an appropriate state, and stable operating characteristics as a permanent magnet motor cannot be obtained.

  The present invention takes the above-mentioned circumstances into consideration, and an object of the present invention is to set the magnetic flux amount of the rotor to an appropriate state with certainty, whereby a stable operating characteristic can be obtained. It is to provide a magnet motor. Another object of the present invention is to provide a hermetic compressor and a refrigeration cycle apparatus having the permanent magnet motor and excellent in reliability.

Permanent magnet motor of the invention according to claim 1, and a stator having a plurality of phase windings is mounted, formed by arranging along the first core and the second core in the axial direction of the rotating shaft rotor, wherein A plurality of V-shaped first magnet housing holes formed at positions surrounding the rotation shaft in the first core, and a plurality of second V-shaped magnets formed at positions surrounding the rotation shaft in the second core. A magnet housing hole and each first magnet housing hole are housed in a two-divided state in accordance with the V shape, and are magnetized or demagnetized by an excitation current supplied from the driving device to each phase winding. And a plurality of second permanent magnets housed in the second magnet housing holes in a split state in accordance with the V-shape and having no change in magnetic force regardless of the supply of the excitation current. A width of each first permanent magnet is equal to a width of each second permanent magnet. With even smaller, according to the positional relationship of the said stator of when the magnetizing or demagnetizing the rotor, the end portions of the first permanent magnet of the two-divided state in each first magnet containing hole close or Separate.

  According to a sixth aspect of the present invention, there is provided a hermetic compressor in which the permanent magnet motor according to any one of the first to fifth aspects of the present invention and a compression mechanism driven by the permanent magnet motor are housed in a hermetic container. Yes.

  The refrigeration cycle apparatus of the invention according to claim 7. It consists of a hermetic compressor of the invention concerning Claim 6, a condenser, an expansion device, and an evaporator.

  According to the permanent magnet motor of the present invention, the amount of magnetic flux of the rotor of the permanent magnet motor can be set to an appropriate state, and stable operating characteristics of the permanent magnet motor can be obtained. In addition, a hermetic compressor and refrigeration cycle apparatus having the permanent magnet motor and excellent in reliability can be obtained.

The figure which shows the structure of the refrigerating-cycle apparatus in each embodiment, and the structure inside the hermetic compressor mounted in this refrigerating-cycle apparatus. The figure which shows schematically the structure of the rotor of a hermetic compressor in 1st Embodiment, and each permanent magnet. The figure which looked at the structure of the 1st core of the rotor of the hermetic compressor in a 1st embodiment, and each permanent magnet stored in the 1st core from the upper part. The figure which looked at the structure of each 2nd core of the rotor of the hermetic compressor in 1st Embodiment, and each permanent magnet accommodated in the 2nd core from upper direction. The figure which looked at the structure of the stator, each phase winding, rotor, and each permanent magnet of the hermetic compressor in a 1st embodiment from the upper part. The block diagram which shows the structure of the drive device and phase winding in each embodiment. FIG. 7 is a waveform diagram of a voltage induced in a non-energized phase winding in FIG. 6. The figure for demonstrating the three-phase excitation for magnetization or demagnetization of each permanent magnet in each embodiment. The figure which shows the position of the width direction of each permanent magnet in 1st Embodiment, and the relationship of a magnetizing force. The figure which shows the relationship between the magnetic flux density and magnetizing force of each permanent magnet in each embodiment. The figure which looked at the 1st core of the rotor in a 2nd embodiment from the upper part. The figure which looked at the 2nd core of the rotor in a 2nd embodiment from the upper part. The figure which shows the magnetic force distribution of the width direction of each permanent magnet in 2nd Embodiment. The figure which looked at the structure of the 1st core of the rotor in 3rd Embodiment, and each permanent magnet accommodated in the 1st core from the upper direction. The figure which looked at the structure of the 2nd core of the rotor in 3rd Embodiment, and each permanent magnet accommodated in the 2nd core from the upper direction. The figure for demonstrating the two-phase excitation for magnetization or demagnetization of each permanent magnet in each embodiment. The figure which looked at the structure when the width | variety of each permanent magnet in 3rd Embodiment is not appropriate from the upper direction. The figure which shows the magnetic force distribution of the width direction of each permanent magnet in FIG. The figure which shows magnetic flux distribution of the stator and rotor in 6th Embodiment. The figure which shows the magnetic force distribution of the width direction of the permanent magnet in 6th Embodiment.

[1] A first embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a configuration of a refrigeration cycle apparatus such as an air conditioner or a refrigerator, and an internal configuration of a hermetic compressor mounted on the refrigeration cycle apparatus. The hermetic compressor 1 is covered with a metal hermetic container 1a. Two suction ports 2a and 2b are attached to the lower part of the sealed container 1a, and one discharge pipe 3 is attached to the upper part. One end of a condenser 31 is connected to the discharge pipe 3 via a high-pressure side pipe, and one end of an evaporator 33 is connected to the other end of the condenser 31 via an expansion device such as an expansion valve 32. The other end of the evaporator 33 is connected to the suction ports 2a and 2b via an accumulator 34 and two suction pipes 35.

  A permanent magnet electric motor 10 and a compression mechanism unit 20 are housed separately in the sealed container 1a. The permanent magnet motor 10 includes a cylindrical stator 11 provided so as to be in contact with the inner peripheral surface of the hermetic container 1a, and a rotor 12 provided rotatably inside the stator 11. A rotation shaft (also referred to as a shaft) 13 is inserted through the center of the rotor 12, and the rotation shaft 13 is coupled to the compression mechanism portion 20 below.

  The compression mechanism unit 20 includes two compression chambers 21a and 21b communicating with the suction ports 2a and 2b, and rollers 22a and 22b that rotate eccentrically in response to the rotation of the rotary shaft 13 in the compression chambers 21a and 21b. The gas refrigerant in the compression chambers 21a, 21b is compressed by the eccentric rotation of the rollers 22a, 22b and discharged into the sealed container 1a. The discharged gas refrigerant flows to the condenser 31 through the discharge pipe 3.

  As shown in FIG. 2, the rotor 12 of the permanent magnet motor 10 includes a first core 12a formed by stacking a large number of circular steel plates and a second core 12b formed by stacking a plurality of circular steel plates. Are arranged along the axial direction of the rotary shaft 13.

As shown in FIG. 3, each of the first core 12a and the second core 12b has a rotation shaft insertion hole 41a at the center, and linear magnets are positioned at four substantially square sides surrounding the rotation shaft insertion hole 41a. A housing hole 42 is provided. These magnet accommodation holes 42 have a depth shape that penetrates the cores 12a and 12b along the rotation shaft insertion hole 41a. Then, the plate-shaped, four-pole (= 4) first permanent magnets 43 having low coercive force are accommodated in the four magnet accommodating holes 42 of the first core 12a. These first permanent magnets 43 have a width W1 that is smaller than the width of the magnet housing hole 42 in the elongated direction, and are housed and fixed in a state in which the center position of the width W1 corresponds to the widthwise center of the magnet housing hole 42. The Also, as shown in FIG. 4, plate-like, high coercivity, four-pole second permanent magnets 44 are accommodated in the four magnet accommodation holes 42 of the second core 12b, respectively. These second permanent magnets 44 have substantially the same width W as the width of the magnet housing hole 42 in the elongated direction. Therefore, the width W 1 of the first permanent magnet 43 is smaller than the width W of the second permanent magnet 44.
Further, as shown in FIG. 5, a plurality of magnetic pole teeth are formed on the inner peripheral surface of the stator 11, and three phase windings Lu, Lv, Lw are concentratedly mounted on these magnetic pole teeth. The rotor 12 rotates due to the interaction between the magnetic field generated by the phase windings Lu, Lv, and Lw and the magnetic field generated by the permanent magnets 43 and 44.

  Further, as shown in FIG. 6, the phase windings Lu, Lv, Lw are star-connected at a neutral point C, and a driving device is connected to the non-connected ends of the phase windings Lu, Lv, Lw. . The drive device includes a forward conversion unit 51 that converts an AC voltage of a commercial AC power supply 50 into a DC voltage, a switching circuit 52 connected to an output terminal of the forward conversion unit 51, and a control unit that controls switching of the switching circuit 52. 53, a two-phase energization position detector 54 connected to each energization line between the switching circuit 52 and the phase windings Lu, Lv, Lw, and 2 between the switching circuit 52 and the phase windings Lu, Lv, Lw. It comprises current sensors 55 and 56 provided on one energization line, a sensorless vector control unit 57 connected to the current sensors 55 and 56, and the like.

  The switching circuit 52 is provided with a series circuit of a pair of switching elements for three phases, a series circuit of switching elements U + and U− for U phase, a series circuit of switching elements V + and V− for V phase, It has a series circuit of switching elements W + and W− for the W phase, and converts the output voltage (DC voltage) of the forward converter 51 into a three-phase AC voltage. The non-connection end of the phase winding Lu is connected to the interconnection point of the switching elements U + and U− of the switching circuit 52, and the non-connection end of the phase winding Lv is connected to the interconnection point of the switching elements V + and V−. The non-connection end of the phase winding Lw is connected to the interconnection point of the switching elements W + and W−, and the control unit 53 is connected to the base of each switching element.

  The two-phase energization position detecting unit 54 is a voltage induced in one phase winding in a non-energized state during two-phase energization in which current sequentially flows in two phase windings of the three phase windings Lu, Lv, and Lw. To detect the rotational position of the rotor 12. FIG. 7 shows a waveform of a voltage induced in one phase winding in a non-energized state. That is, the level of the induced voltage and the reference potential (1/2 of the DC voltage or a virtual neutral point potential created by a resistor) are compared, and from the timing when the level of the induced voltage crosses the reference potential, the rotor Twelve rotational positions can be detected.

  The sensorless vector control unit 57 estimates the rotational position of the rotor 12 by vector control based on currents detected by the current sensors 55 and 56.

  In the case of two-phase energization driving, the control unit 53 turns on one switching element of one phase in the switching circuit 52 and turns off the other switching element, and simultaneously turns one switching element of another phase on. By sequentially switching the two-phase energization that turns off and turns on the other switching element, the two-phase energization drive in which current flows sequentially through the two phase windings Lu, Lv, and Lw is controlled. The on / off timing of each switching element of the switching circuit 52 is controlled in accordance with the rotational position detected by the two-phase energization position detection unit 54 or the rotational position estimated by the sensorless vector control unit 57.

  Further, in the case of sensorless vector control, the control unit 53 controls the on / off timing for each switching element of the switching circuit 52 according to the rotational position estimated by the sensorless vector control unit 57, and the sine wave PWM is controlled. Outputs a three-phase waveform.

  The two-phase energized position detecting unit 54 and the sensorless vector control unit 57 are used for detecting the rotational position. However, at least one of them is sufficient, and the control unit 53 is a switching circuit according to each driving method. The on / off timing of each switching element 52 is controlled. However, if the two-phase energization position detection circuit 54 is used, it is not possible to increase the rotation speed with a field weakening as in the case of using the sensorless vector control unit 57, and the operating current becomes a rectangular wave, so that the motor noise Therefore, it is preferable to use the sensorless vector control unit 57 in normal operation.

  In the permanent magnet electric motor 10 having such a configuration, each of the first coercive magnets 43 having a low coercive force housed in the first core 12a of the rotor 12 includes the stator 11 and the rotor 12 as shown in FIG. In the positional relationship, as shown in FIG. 8, the excitation voltage Ed is applied to the phase windings Lu, Lv, Lw and the excitation current is supplied to the phase windings Lu, Lv, Lw, thereby magnetizing or demagnetizing. Thus, the magnetic force can be changed. At this time, each of the second permanent magnets 44 having a high coercive force housed in the second core 12b of the rotor 12 has a high coercive force, so even if an excitation current is supplied to the phase windings Lu, Lv, and Lw. The magnetic force does not change. That is, the first core 12a is variable in magnetic flux, and the second core 12b is non-variable in magnetic flux.

  When magnetizing each first permanent magnet 43 of the first core 12a, two opposing first permanent magnets 43 (A) and 43 (A) facing the phase winding Lu shown in FIG. 9 and the remaining two first permanent magnets 43 (B) and 43 (B) facing each other not facing the phase winding Lu have different magnetizing forces as shown in FIG. That is, when the rotation stop position of the rotor 12 is in the illustrated state, the magnetic force of the first permanent magnets 43 (A) and 43 (A) is large, and the magnetic force of the first permanent magnets 43 (B) and 43 (B) is small. Become. Therefore, after the first magnetization is completed, the rotor 12 is rotated by 90 °, and the second magnetization is performed by supplying the excitation current having the opposite polarity to the phase windings Lu, Lv, Lw again. The magnetization force of each first permanent magnet 43 can be set to substantially the same state.

  However, also in the first permanent magnets 43 (A) and 43 (A), the magnetizing force decreases from the center of the magnetic pole to the end, and at the end of the magnetic pole, magnetization caused by current, temperature, permanent magnet characteristics, etc. Variations increase. For this reason, the amount of magnetic flux cannot be reliably changed, and the characteristics of the permanent magnet motor 10 are adversely affected.

  Therefore, the width of each first permanent magnet 43 of the first core 12a is set to W1 smaller than the width of each second permanent magnet 44 of the second core 12b. Furthermore, the width direction center part of each first permanent magnet 43 is made to correspond to the width direction center part of each magnet accommodation hole 42.

  In this way, by limiting the width of each first permanent magnet 43 to W1 at which a large magnetizing force is obtained, the magnetizing force of each first permanent magnet 43 is stabilized. Thereby, the magnetic flux amount of the rotor 12 can be reliably set to an appropriate state, and stable operating characteristics of the permanent magnet motor 10 can be obtained. Moreover, since the width | variety of each 1st permanent magnet 43 becomes small with W1, the quantity of each 1st permanent magnet 43 can be reduced and cost reduction can be aimed at.

  The excitation for magnetization or demagnetization is performed even when the rotor is stopped and the positional relationship between the stator and the rotor is as shown in FIG. It may be performed when the state shown in FIG.

  Since each second permanent magnet 44 having a high coercive force is previously magnetized with a large current, a sufficient magnetizing force can be applied to the end portion even if the width is large.

Here, the operation of the permanent magnet will be described using the BH curve shown in FIG.
The operation of the permanent magnet in the magnetic circuit is determined by the BH curve of the permanent magnet and the permeance coefficient Pc determined by the magnetic circuit and the permanent magnet, and operates at the intersection p between the BH curve and the permeance line (Pc line). . The permanent magnet is magnetized at the magnetic flux density B0 at this operating point p. At this time, if the d-axis component of the rotating magnetic flux generated from the stator is increased in the negative direction, a negative direction magnetizing force is applied to the permanent magnet, and the permeance line is translated in the negative direction (the left direction in the figure). Moves to p1, and the magnetic flux density decreases to B1. On the other hand, when the d-axis component of the rotating magnetic flux generated from the stator is increased in the positive direction, a permanent magnetizing force is applied to the permanent magnet, the permeance line is translated in the positive direction (right direction in the figure), and the operating point is Moving to p2, the magnetic flux density rises to B2.

  As described above, there is no doubt that the magnetic flux density of the permanent magnet can be changed by increasing or decreasing the d-axis component of the rotating magnetic flux generated from the stator, so that the amount of magnetic flux can be increased or decreased. However, this phenomenon occurs only in the low coercive force permanent magnet. Instead, it also occurs in high coercivity permanent magnets.

The operating point of the permanent magnet moves on the BH curve, and the slope of the BH curve is expressed by the recoil relative permeability μrec. The recoil relative permeability μrec is close to 1 in the rare earth magnet and is substantially equal to the permeability 4π × 10 ⁻⁷ in vacuum. For this reason, in order to greatly change the magnetic flux density, it is necessary to apply a considerably large magnetizing force, and in order to generate a d-axis component magnetic flux for this purpose, a large excitation current is required. In order to increase the excitation current, it is necessary to increase the current capacity of the drive device, and there is a problem that the efficiency of the drive device and the electric motor is reduced.

  In addition, in the thing of patent document 1, although two magnets of high coercive force / low magnetic permeability and low coercive force / high magnetic permeability are combined, the inclination of the BH curve is large in a high magnetic permeability permanent magnet. The change in the magnetic flux density at the operating point due to the magnetizing force is large, and the amount of magnetic flux can be varied with a smaller current. However, this action and the coercive force are irrelevant, and it is meaningless to combine the low coercive force and the high coercive force.

  As described above, the one described in Patent Document 1 basically uses the operation in the straight line portion (recoil wire) of the BH curve of the permanent magnet, and the operation is reversible. (Reversible demagnetization and magnetization).

  On the other hand, if the magnetization of the permanent magnet is changed irreversibly, a large change in the amount of magnetic flux can be obtained. This utilizes irreversible demagnetization and remagnetization of a permanent magnet.

  As can be seen from FIG. 10, when a large negative magnetizing force is applied to the permanent magnet, the operating point moves beyond the inflection point of the BH curve. In this way, even if the negative magnetizing force is removed, the permanent magnet cannot return to the original BH curve (irreversible demagnetization occurs), and the operating point becomes the p 'point, and the magnetic flux The density is greatly reduced. At this time, even if a magnetizing force is applied to the permanent magnet having a high coercive force, the operating point does not exceed the bending point, so irreversible demagnetization does not occur, and the original magnetic flux density is restored.

  In order to generate such irreversible demagnetization, an excitation current for applying a negative magnetizing force only for a short time may be supplied. Thereafter, when it is desired to increase the magnetic flux density of the permanent magnet, re-magnetization may be performed by applying a short positive magnetic force. At this time, by utilizing the difference in coercivity on the right side of the permanent magnet and generating irreversible demagnetization only in the low coercivity permanent magnet, it is possible to obtain a large change in the amount of magnetic flux while ensuring a certain amount of magnetic flux. it can.

[2] A second embodiment will be described.
As shown in FIGS. 11 and 12, a plurality of slits 45 are formed on the outer peripheral side of the magnet housing holes 42 in the cores 12 a and 12 b of the rotor 12. These slits 45 have an elongated shape along the radial direction of the cores 12a and 12b, and a depth shape that penetrates the cores 12a and 12b along the rotation shaft insertion hole 41a.

  In addition, each slit 45 is set to have a small interval between the inner peripheral side end in the radial direction of the cores 12a and 12b and each magnet housing hole 42, and rotates with the outer peripheral side end in the radial direction of the cores 12a and 12b. The distance from the outer peripheral edge of the child 12 is set small. With these settings, the portion between the slits 42 is secured as a magnetic path, and the magnetic fluxes of the first permanent magnets 43 and 44 efficiently pass therethrough.

In particular, the presence of each slit 45 regulates the flow of magnetic flux in the circumferential direction of the rotor 12, and as shown in FIG. 13, the distribution of the magnetizing force in each first permanent magnet 43 is changed to each first permanent magnet. The effect | action which enlarges in the center part of the magnet 43 is produced. As a result, the magnetization force of each first permanent magnet 43 is further stabilized.
Other configurations and operations are the same as those of the first embodiment. Therefore, the description is omitted.

[3] A third embodiment will be described.
As shown in FIG. 14, each magnet accommodation hole 42 of the first core 12 a has a V shape, and the first permanent magnets 43 a and 43 b in a two-divided state are accommodated in these magnet accommodation holes 42, respectively. Similarly, as shown in FIG. 15, each magnet accommodation hole 42 of the second core 12 b has a V shape, and the second permanent magnets 44 a and 44 b that are divided into two are accommodated in these magnet accommodation holes 42, respectively. .

  It is the same as the first embodiment in that the combined width of the two first permanent magnets 43a and 43b is smaller than the combined width of the second permanent magnets 44a and 44b. That is, the combined width of the first permanent magnets 43a and 43b is equal to the width W1 of the first permanent magnet 43 in the first embodiment, and the combined width of the second permanent magnets 44a and 44b. Is equivalent to the width W of the second permanent magnet 44 in the first embodiment. The first permanent magnets 43a and 43b are provided so that the ends are in close contact with each other.

  Even in such a case, as in the first embodiment, as shown in FIG. 8, the excitation voltage Ed is applied to the phase windings Lu, Lv, Lw, and the excitation current is applied to the phase windings Lu, Lv, Lw. Can be magnetized or demagnetized to change the magnetic force.

  Other configurations and operations are the same as those of the first embodiment. Therefore, the description is omitted.

  When the stator 11 and the rotor 12 are in the positional relationship as shown in FIG. 17, the excitation voltage Ed is applied to two phase windings of the phase windings Lu, Lv, and Lw as shown in FIG. Then, the first permanent magnet 43a in each magnet housing hole 42 is obtained by performing magnetization or demagnetization for flowing an excitation current at least twice by changing the position of the rotor and the polarity of the excitation current in the same manner as in the first embodiment. 43b can be magnetized or demagnetized in an optimum state.

  However, in this case, as shown in FIG. 18, the magnetic force at the boundary between the first permanent magnets 43 a and 43 b (near the center of each pole) becomes small.

Therefore, in this case, the end portions of the first permanent magnets 43a and 43b shown in FIG. 14 are arranged to be separated from each other, that is, so as to have a space between the end portions of the first permanent magnets 43a and 43b. Thus, the same effect as described above can be obtained.
As shown in FIG. 16, magnetization or demagnetization for applying an excitation voltage Ed to two phase windings of the phase windings Lu, Lv, and Lw to flow an excitation current is performed as shown in FIG. When applied to a rotor in which a single permanent magnet is disposed on each pole, the magnetizing force near the center of each pole is weakened.

Therefore, in this case, the same effect as described above can be obtained by dividing the first permanent magnets 43 having a low coercive force shown in FIG. 3 in the width direction and reducing the respective widths so that a space is formed in the central portion. can get.
The rotor for supplying the exciting current may be stopped or rotating as in the first embodiment.

[4] A fourth embodiment will be described.
In the fourth embodiment, each first permanent magnet 43 is magnetized or demagnetized according to the detection position of the two-phase energization position detection unit 54 while rotating the rotor 12 by driving the two-phase energization.

That is, two-phase energization position detection is performed based on a voltage induced in a non-energized phase winding while performing two-phase energization in which current flows in sequence in each of the phase windings Lu, Lv, and Lw. The unit 54 detects the rotational position of the rotor 12 and supplies an excitation current for magnetization or demagnetization to the phase windings Lu, Lv, Lw at a timing according to the detected rotational position. In this case, the excitation current is supplied as shown in the first embodiment or the third embodiment.
Normally, the position estimation by the sensorless vector control unit 57 has a large error, and is fixed by magnetizing or demagnetizing each first permanent magnet 43 according to the detection position of the two-phase energization position detection unit 54 as described above. Energization for magnetization or demagnetization can be performed with a more accurate positional relationship between the rotor and the rotor, and the certainty of variable magnetic flux is increased.

Incidentally, in the driving of the two-phase energization according to the detection position of the two-phase energization position detecting unit 54, it is not possible to control to increase the rotation speed with the weak field like the sensorless vector control, and the operation current is a rectangular wave. Therefore, since there is a problem that the noise of the permanent magnet motor 10 is increased, it is desirable to drive the three-phase sine wave PWM by vector control according to the estimated position of the sensorless vector control unit 57 during normal operation.
Other configurations and operations are the same as those of the first embodiment. Therefore, the description is omitted.

[5] A fifth embodiment will be described.
During operation of the permanent magnet motor 10, when supplying an excitation current for magnetization or demagnetization, the operation is switched to the operation by the sensorless vector control unit 57 at an appropriate timing according to the detection position of the two-phase energization position detection unit 54, and the phase winding A d-axis current is supplied to Lu, Lv, and Lw.

  In this case, the d-axis current is supplied so as to be superimposed on the q-axis current for generating the operating torque.

When the d-axis and q-axis currents are supplied, the position detection by the two-phase energization position detection unit 54 cannot be performed, so the operation is switched to the operation by the sensorless vector control unit 57.

  Since the energization of magnetization or demagnetization is started according to the detection position of the two-phase energization position detector 54 as in the fourth embodiment, the magnetization or demagnetization is performed with a more accurate positional relationship between the stator and the rotor. Can be energized, and the certainty of magnetic flux variation is increased.

As in the fifth embodiment, it is possible to execute the d-axis current through the phase windings Lu, Lv, and Lw in the program of the sensorless vector control, and no special control software is required. There are advantages.
Other configurations and operations are the same as those of the first embodiment. Therefore, the description is omitted.

[6] A sixth embodiment will be described.
During operation of the permanent magnet motor 10, an excitation current for magnetization or demagnetization is supplied. Specifically, the operation is switched to the operation by the sensorless vector control unit 57 at an appropriate timing according to the detection position of the two-phase energization position detection unit 54, and the d-axis current is converted into an electrical angle as an excitation current for the phase windings Lu, Lv, Lw. At 80 ° or more.

  In the concentrated winding stator 11, the magnetization force applied to each first permanent magnet 43 varies greatly depending on the position of each first permanent magnet 43 when a magnetizing or demagnetizing d-axis current is passed. The distribution changes depending on the positional relationship between the stator 11 and the rotor 12. This is because when the d-axis current is passed through the phase windings Lu, Lv, Lw of the stator 11, the magnetic flux generated in the stator 11 and the rotor 12 becomes asymmetric as shown in FIG. The distribution of the magnetizing force applied to one permanent magnet 43 changes according to the rotational position of the rotor 12 as shown in FIG.

  The angle in FIG. 20 represents an electrical angle, and the rotor 12 rotates 60 ° between 0 ° and 120 ° (because it has four poles), during which the magnetization force distribution of each first permanent magnet 43 changes continuously. I will do it.

  Therefore, when the energization is performed for a short period (for example, about 30 ° in electrical angle), a portion where a sufficient magnetizing force for magnetization or demagnetization is not applied to a part of each first permanent magnet 43 is generated.

  The change in the magnetizing force distribution due to the positional relationship between the stator 11 and the rotor 12 has an electrical angle of 120 ° as one cycle. A magnetic field or a demagnetizing magnetic field is applied, and the entire first permanent magnets 43 can be surely magnetized and demagnetized.

  Note that, by selecting an appropriate period of electrical angle, practically a uniform magnetic field for demagnetization or demagnetization can be obtained even in an electrical angle period of 80 °.

[7] A seventh embodiment will be described.
As in the fourth embodiment, the rotor 12 is rotated by the two-phase energization drive, and the phase windings Lu, Lv, Lw are magnetized or demagnetized according to the detection position of the two-phase energization position detection unit 54. For this reason, the first permanent magnets 43 are magnetized or demagnetized.

Then, after supplying the exciting current, the amount of magnetic flux generated in the first core 12a of the rotor 12 from the induced voltage detected by the two-phase energization position detecting unit 54 while rotating the rotor 12 by driving the two-phase energization. When the obtained magnetic flux amount does not reach the target value, the phase windings Lu and Lu according to the detection position of the two-phase energization position detection unit 54 while rotating the rotor 12 by driving the two-phase energization again. An excitation current for magnetization or demagnetization is supplied to Lv and Lw, and each first permanent magnet 43 is magnetized or demagnetized.
In this way, a desired magnetic flux can be reliably obtained by performing re-magnetization or demagnetization.

  Regarding the amount of magnetic flux, the induced voltage, the number of poles (corresponding to the number of permanent magnets in one core of the rotor 12), the number of turns of the phase windings Lu, Lv, Lw, the number of rotations of the rotor 12, etc. are determined in advance. It can be calculated by substituting into a predetermined mathematical expression.

In the driving of the two-phase energization according to the detection position of the two-phase energization position detection unit 54, it is not possible to control to increase the rotation speed by the weak field like the sensorless vector control, and the operation current becomes a rectangular wave. Since there is a problem that the noise of the permanent magnet motor 10 is increased, it is desirable to drive the two-phase energization according to the estimated position of the sensorless vector control unit 57 during normal operation.
When shifting to the normal operation of the two-phase energization drive according to the estimated position of the sensorless vector control unit 57, the calculated magnetic flux amount can be used as a motor constant for sensorless vector control. Thereby, two-phase energization driving with good sensorless vector control becomes possible.

[8] Modification
In each of the above embodiments, the so-called four-pole permanent magnet motor 10 in which the number of permanent magnets provided in one core of the rotor 12 is four has been described as an example, but six permanent magnets are provided in one core. The same can be applied to the case of using a permanent magnet motor 10 having a six-pole configuration provided with magnets. Moreover, although the case where the phase windings Lu, Lv, and Lw are concentrated winding mounted on the slots of the stator 11 has been described as an example, the same can be applied to the case of distributed winding mounting.

  In addition, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. It is also possible to delete some components from all the components shown in each embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Hermetic compressor, 10 ... Permanent magnet motor, 11 ... Stator, 12 ... Rotor, 12a ... 1st core, 12b ... 2nd core, 31 ... Condenser, 32 ... Expansion device, 33 ... Evaporator, 41a ... Rotating shaft insertion hole, 42 ... Magnet housing hole, 43 ... First permanent magnet, 44 ... Second permanent magnet, 45 ... Slit, Lu, Lv, Lw ... Phase winding, 50 ... Commercial AC power supply, 51 ... Forward Conversion unit, 52 ... switching circuit, 53 ... control unit, 54 ... two-phase energization position detection unit, 57 ... sensor vector control unit

Claims (7)

A stator equipped with a plurality of phase windings;
A rotor formed by arranging the first core and the second core along the axial direction of the rotation axis;
A plurality of V-shaped first magnet housing holes formed at positions surrounding the rotation shaft in the first core;
A plurality of V-shaped second magnet receiving holes formed at positions surrounding the rotating shaft in the second core;
Each of the first magnet accommodating holes is accommodated in a two-divided state in accordance with the V shape, and is magnetized or demagnetized by an excitation current supplied from the driving device to the phase windings to change the magnetic force. A first permanent magnet;
A plurality of second permanent magnets that are accommodated in the second magnet accommodation holes in a two-divided state in accordance with the V shape, and that do not change in magnetic force regardless of the supply of the excitation current,
With
The width of each first permanent magnet is made smaller than the width of each second permanent magnet ,
According to the positional relationship between the stator and the rotor at the time of magnetization or demagnetization, the ends of the first permanent magnets in the two-divided state in the first magnet housing holes are closely or separated from each other,
A permanent magnet motor characterized by that.   2. The permanent magnet electric motor according to claim 1, further comprising a plurality of slits formed on an outer peripheral side of a housing portion of each permanent magnet in the rotor. The driving device includes:
Detecting the rotational position of the rotor based on the voltage induced in the non-energized phase winding while performing two-phase energization in which current sequentially flows through the two phase windings of each phase winding, Control means for supplying an excitation current for magnetization or demagnetization to each phase winding at a timing according to the detected rotational position;
The permanent magnet motor according to claim 1, further comprising:   4. The driving apparatus according to claim 3, wherein the excitation current is a d-axis current of sensorless vector control. The driving device includes:
Detecting the rotational position of the rotor based on the voltage induced in the non-energized phase winding while performing two-phase energization in which current sequentially flows through the two phase windings of each phase winding, First control means for supplying an excitation current for magnetization or demagnetization to each phase winding at a timing according to the detected rotational position;
After the excitation current is supplied by the first control means, the two-phase energization in which the current sequentially flows through the two phase windings of each phase winding, while the voltage induced in the non-energized phase winding is Second control means for obtaining the amount of magnetic flux generated in the first core of the rotor, and executing the supply of excitation current by the first control means again when the obtained magnetic flux amount does not reach the target value;
The permanent magnet motor according to claim 1, further comprising:   6. A hermetic compressor, wherein the permanent magnet motor according to claim 1 and a compression mechanism portion driven by the permanent magnet motor are housed in a hermetic container.   A refrigeration cycle apparatus comprising the hermetic compressor according to claim 6, a condenser, an expansion device, and an evaporator.

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