JP2014183613A - Control method and control device for brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve torque increase and low torque ripple by reducing armature reaction of a brushless motor.SOLUTION: A brushless motor 3, which is a magnetic flux concentration type motor in which rotor magnets 45 are radially arranged, has a 14P12S structure comprising: 14 pieces of pseudo magnetic pole parts 47 formed by 14 pieces of magnets 45; and 12 pieces of slots 29. A control device 50 has a supplied current quantity calculating section 51 configured to calculate an advance angle value to be set for a motor supply current on the basis of the load state of the brushless motor 3, and configured to exert advance angle control for the brushless motor 3. The control device 50 has an advance angle control map 63 indicating the load torque of the motor and an advance angle. The supplied current quantity calculating section 51 sets a retard angle value with reference to this map.

Description

  The present invention relates to a brushless motor control technique, and more particularly to a brushless motor control technique used as a drive source for an electric power steering apparatus, and to a technique for reducing armature reaction in a magnetic flux concentration type brushless motor for an electric power steering apparatus.

  Conventionally, as a motor for an electric power steering device (hereinafter abbreviated as EPS), an SPM (Surface Permanent Magnet) motor in which an arc-shaped or kamaboko-shaped magnet is arranged on the surface of a rotor has been widely used. However, such an SPM motor has a problem that it is necessary to process the magnet into a predetermined shape and the yield of the magnet is poor, and in recent years, a rectangular parallelepiped permanent magnet is embedded in the rotor as an EPS drive source. The use of so-called IPM (Interior Permanent Magnet) type motors (hereinafter abbreviated as IPM motors) is increasing.

  This IPM motor has a large inductance difference between the d-axis (center axis of the permanent magnet) direction and the q-axis (axis that is electrically and magnetically orthogonal to the d-axis) because the magnet is embedded in the rotor. A reluctance torque Tr is generated in the rotor. Therefore, in the IPM motor, the reluctance torque Tr can be used together with the magnet torque Tm by the permanent magnet, and there is an advantage that the total torque Tt of the entire motor can be increased. For this reason, the use of IPM motors is expanding not only for the aforementioned EPS but also for electric motors, hybrid cars, home appliances such as air conditioners, various industrial machines and the like as high-efficiency and high-torque motors.

  On the other hand, in the IPM motor, when the armature current increases, the ratio of the magnet torque Tm and the reluctance torque Tr to the total torque Tt changes, and the Tr side tends to increase. In this case, since the current value is high, the influence of the armature reaction is increased correspondingly, and the torque ripple is increased as compared with a low current. In particular, when the reluctance torque exceeds 10%, the torque ripple increases abruptly and the torque ripple rate exceeds 5%, which is the upper limit in EPS.

  Therefore, in order to reduce the armature reaction, a magnetic flux concentration type brushless motor having a rotor in which a plurality of magnets are arranged radially around a rotating shaft has been proposed. FIG. 9 is an explanatory view showing a rotor configuration of such a magnetic flux concentration type brushless motor. As shown in FIG. 9, in the rotor 71, the magnets 72 and the core members 73 are alternately arranged in the circumferential direction, and the adjacent magnets 72 have opposite surfaces having the same polarity. Magnetic fluxes from the magnets 72 repel each other in the core member 73 and concentrate in the outer circumferential direction (arrow P). As a result, a pseudo magnetic pole portion 74 is formed on the outer periphery of the rotor 71 along the circumferential direction, and becomes a magnetic pole on the rotor side.

  In such a magnetic flux concentration type brushless motor, by setting the rotor 71 to a magnetic flux concentration type configuration, two magnets are arranged per magnetic pole (pseudo magnetic pole portion 74). For this reason, a magnetic flux larger than that of a normal SPM motor can be obtained. Further, by decentering the outer peripheral center of the core member 73 with respect to the center of the rotor 71, a pseudo smooth magnetic pole can be obtained and cogging can be reduced. Furthermore, in the structure of FIG. 9, since the q-axis magnetic path is only on the outer surface in the magnet radial direction, Lq is very small and the reluctance torque is also small. Therefore, torque ripple in the high load region as described above is also reduced, and a motor with high output, low cogging, and low torque ripple can be obtained.

Japanese Patent Laid-Open No. 2004-64909 Japanese Patent No. 4019842

  However, in the magnetic flux concentration type brushless motor as shown in FIG. 9, the rotor 71 is formed of an electromagnetic steel plate (for example, a silicon steel plate) having a high magnetic permeability. It is easy to be affected by the magnetic flux. For this reason, even in the magnetic flux concentration type brushless motor, the magnetic flux on the rotor 71 side is easily distorted due to the influence of the armature reaction. In the magnetic flux concentration type brushless motor, when such an armature reaction occurs, a so-called torque sagging in which the rate of increase in torque decreases in a high load region (high current region) and an induced voltage that is not as large as that of an IPM motor. There was a problem that torque ripple was generated due to the deviation of the waveform.

  An object of the present invention is to reduce the armature reaction in a magnetic flux concentration type motor, thereby suppressing torque sagging in a high load region, reducing torque ripple, and increasing torque and reducing torque ripple of an EPS brushless motor. There is.

  The control method of the present invention includes a plurality of teeth portions protruding radially inward, a plurality of slots formed between the teeth portions, and wound around the teeth portions via the slots. A stator having a plurality of armature windings having an induced voltage of a sinusoidal waveform, a core that is rotatably arranged inside the stator, and is formed by laminating electromagnetic steel plates, and in the core A rotor provided with a plurality of magnet housing portions formed radially, a plurality of permanent magnets respectively housed in the magnet housing portions, and a plurality of pseudo magnetic pole portions formed between the magnet housing portions And controlling the advance angle of the brushless motor based on the load state of the brushless motor.

  In the present invention, the adoption of a magnetic flux concentrating motor in which magnets are arranged radially reduces the manufacturing cost, and the magnetic pole density of the pseudo magnetic pole portion is increased by the multi-polarization of the pseudo magnetic pole portion, thereby reducing the armature reaction. Figured. Furthermore, by performing advance angle control, torque sagging is suppressed and output is improved, and torque ripple is also suppressed.

  In the control method, the advance angle control may be performed based on a map showing a relationship between a load torque of the brushless motor and the advance angle.

  In the control method, the stator includes twelve teeth portions and twelve slots, and the rotor includes fourteen magnet housing portions, fourteen magnets, and fourteen slots. The pseudo magnetic pole portion may be provided. By adopting such a 14P12S structure, magnetostriction noise is suppressed and motor operation noise is reduced.

  In the control method, the brushless motor is used as a drive source of electric power steering, and the electric power steering device includes a torque sensor that detects a load state of the brushless motor, and a value detected by the torque sensor. The advance angle value set for the current supplied to the armature winding may be calculated based on the above, and the advance angle control may be performed on the brushless motor.

  In the present invention, by performing advance angle control, torque sagging in a high load region can be suppressed, and output can be improved. Further, the torque ripple can be suppressed by the advance angle control, and when this brushless motor is used as a drive source of the electric power steering apparatus, it is possible to improve the steering feeling.

  Further, the control device of the present invention is used as a drive source of the electric power steering device, a plurality of teeth portions projecting radially inward, a plurality of slots formed between the teeth portions, A stator comprising a plurality of armature windings wound around the teeth portion through the slot and having an induced voltage between the wires having a sinusoidal waveform; and an electromagnetic steel plate rotatably disposed inside the stator. A core formed by laminating a plurality of magnets, a plurality of magnet housing portions formed radially in the core, a plurality of permanent magnets respectively housed in the magnet housing portions, and formed between the magnet housing portions. A brushless motor control device having a plurality of pseudo magnetic pole portions, wherein the electric power steering device detects a load state of the brushless motor. The controller has a torque sensor, and the controller calculates an advance value to be set for the current supplied to the armature winding based on the load state of the brushless motor detected by the torque sensor. And a supply current amount calculation unit for performing advance angle control on the brushless motor.

  In the present invention, the adoption of a magnetic flux concentrating motor in which magnets are arranged radially reduces the manufacturing cost, and the magnetic pole density of the pseudo magnetic pole portion is increased by the multi-polarization of the pseudo magnetic pole portion, thereby reducing the armature reaction. Figured. Furthermore, by performing advance angle control by the supply current amount calculation unit, torque sagging is suppressed and output is improved, and torque ripple is also suppressed.

  The control device may further include a map showing a relationship between a load torque of the brushless motor and the advance angle, and the supply current amount calculation unit may calculate the advance value based on the map.

  In the control device, the stator includes twelve teeth portions and twelve slots, and the rotor includes fourteen magnet housing portions, fourteen magnets, and fourteen slots. The pseudo magnetic pole portion may be provided. By adopting such a 14P12S structure, magnetostriction noise is suppressed and motor operation noise is reduced.

  According to the control method of the present invention, it is possible to reduce the manufacturing cost by adopting a magnetic flux concentrating motor in which magnets are arranged radially as a brushless motor, and the magnetic flux of the pseudo magnetic pole part can be reduced by increasing the number of pseudo magnetic pole parts. The density can be increased and the armature reaction can be reduced. Furthermore, by performing advance angle control, torque sagging in a high load region can be suppressed, and output can be improved. Further, the torque ripple can be suppressed by the advance angle control, and when this brushless motor is used as a drive source of the electric power steering apparatus, it is possible to improve the steering feeling.

  According to the control device of the present invention, as a brushless motor for an electric power steering device, by adopting a magnetic flux concentration type motor in which magnets are arranged radially, it is possible to reduce the manufacturing cost and to increase the number of pseudo magnetic pole portions. The magnetic flux density of the pseudo magnetic pole part is increased, and the armature reaction can be reduced. Furthermore, by performing advance angle control, torque sagging in a high load region can be suppressed, and output can be improved. Further, the torque ripple can be suppressed by the advance angle control, and the steering feeling can be improved.

It is explanatory drawing which shows the structure of EPS using a brushless motor. It is sectional drawing which shows the structure of the brushless motor used by EPS of FIG. It is sectional drawing along the AA line of FIG. It is explanatory drawing which shows the structure of the magnet attachment hole vicinity. It is a block diagram which shows the structure of the control apparatus which performs drive control of EPS of FIG. It is the graph which showed the relationship between a torque and electromagnetic force pulsation. It is explanatory drawing which shows an example of an advance angle control map. It is explanatory drawing which shows the change of the torque and torque ripple with the presence or absence of advance angle control. It is explanatory drawing which shows the rotor structure of the conventional magnetic flux concentration type brushless motor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing a configuration of an EPS using a brushless motor, and a control process according to the present invention is performed. An electric power steering apparatus (EPS) 1 shown in FIG. 1 has a column assist type structure that applies an operation assisting force to a steering shaft 2, and a brushless motor 3 (hereinafter abbreviated as a motor 3) to which the present invention is applied. Is used as a power source.

  A steering wheel 4 is attached to the steering shaft 2, and the steering force of the steering wheel 4 is transmitted to the tie rod 6 via a pinion and a rack shaft (not shown) disposed in the steering gear box 5. Wheels 7 are connected to both ends of the tie rod 6, and the tie rod 6 is operated in accordance with the operation of the steering wheel 4, and the wheels 7 are steered left and right via a knuckle arm or the like (not shown).

  In the EPS 1, an assist motor unit 8 that is a steering force assist mechanism is provided on the steering shaft 2. The assist motor unit 8 includes a motor 3 and a speed reduction mechanism unit 9 and a torque sensor 11. A worm and a worm wheel (not shown) are arranged in the speed reduction mechanism section 9, and the rotation of the motor 3 is decelerated and transmitted to the steering shaft 2 by the speed reduction mechanism section 9. The motor 3 and the torque sensor 11 are connected to a control device (ECU) 12.

  When the steering wheel 4 is operated and the steering shaft 2 rotates, the torque sensor 11 is activated. The ECU 12 appropriately supplies electric power to the motor 3 based on the torque detected by the torque sensor 11. When the motor 3 is actuated, the rotation is transmitted to the steering shaft 2 via the speed reduction mechanism unit 9 and a steering assist force is applied. The steering shaft 2 is rotated by the steering assist force and the manual steering force, and this rotational motion is converted into a linear motion of the rack shaft by rack-and-pinion coupling in the steering gear box 5, and the steering operation of the wheels 7 is performed. Is done.

  2 is a cross-sectional view of the motor 3 used as a driving source of the EPS 1, and FIG. 3 is a cross-sectional view taken along the line AA of FIG. The motor 3 is a so-called spoke-type magnetic flux concentration motor in which rotor magnets are arranged radially. As shown in FIG. 3, the motor 3 is an inner rotor type brushless motor in which a stator (stator) 21 is disposed on the outer side and a rotor (rotor) 22 is disposed on the inner side.

  The stator 21 is fixed inside a bottomed cylindrical motor case 23 (hereinafter abbreviated as case 23) by fixing means such as press fitting or adhesive. The stator 21 is attached to and electrically connected to the stator core 24, a stator coil 26 (armature winding, hereinafter abbreviated as a coil 26) wound around the teeth 25 of the stator core 24, and the stator core 24. It comprises a bus bar unit (terminal unit) 27. The case 23 is formed in a bottomed cylindrical shape with iron or the like, and a bracket 28 (for example, made of aluminum die cast) is attached to an opening of the case 23 by a fixing screw (not shown).

  The stator core 24 is formed by laminating steel plate materials (for example, electromagnetic steel plates such as silicon steel plates), and a plurality (12 in this embodiment) of teeth 25 project radially inward. Has been. A slot 29 is formed between adjacent teeth 25, and the motor 3 has a 12-slot configuration. An insulator 31 made of synthetic resin is attached to the stator core 24, and a plurality of phases (here, U-phase, V-phase, and W-phase) coils 26 are wound around the insulator 31. The coil 26 is housed in a slot 29 and is configured such that the induced voltage between the lines has a sinusoidal waveform.

  A bus bar unit 27 is attached to one end side of the stator core 24 on the opening side of the case 23. The bus bar unit 27 has a structure in which a copper bus bar is insert-molded in a synthetic resin main body. Around the bus bar unit 27, a plurality of power feeding terminals 32 extending from each bus bar are projected in the radial direction. When the bus bar unit 27 is attached, the end portions 26a of the coils 26 drawn from the stator core 24 are electrically welded to the power supply terminals 32, respectively. In the bus bar unit 27, the number of bus bars corresponding to the number of phases of the motor 3 (here, three for the U phase, V phase, W phase and one for connecting each phase) is provided. Yes. Each coil 26 is electrically connected to a power supply terminal 32 corresponding to the phase. After the bus bar unit 27 is attached, the stator core 24 is fixed in the case 23 by press fitting or the like.

  A rotor 22 is inserted inside the stator 21. The rotor 22 has a rotor shaft 33, and the rotor shaft 33 is rotatably supported by bearings 34a and 34b. The bearing 34 a is fixed to the center of the bottom of the case 23, and the bearing 34 b is fixed to the center of the bracket 28. A cylindrical rotor core 35 and a rotor (resolver rotor) 37 of a resolver 36 serving as a rotation angle detection unit are attached to the rotor shaft 33. A stator (resolver stator) 38 of the resolver 36 is accommodated in a resolver bracket 39 made of synthetic resin, and is fixed to the inside of the bracket 28 by an attachment screw 41.

  The rotor core 35 is configured by laminating a plurality of thin core plates (electromagnetic steel plates) formed of a magnetic material such as a silicon steel plate. The outer shape of the rotor core 35 is not a perfect circle but an eccentric shape. The rotor core 35 is provided with a shaft hole (center hole) 42 and a plurality of magnet mounting holes (magnet housing portions) 43. The shaft hole 42 is formed at the center of the rotor core 35, and the rotor shaft 33 is press-fitted and fixed therein. The magnet mounting holes 43 are rectangular holes extending in the radial direction, and 14 are arranged radially at equal intervals in the circumferential direction. That is, the motor 3 has 14 poles and 12 slots (hereinafter abbreviated as 14P12S).

  The inner side and the outer side in the radial direction of the magnet mounting hole 43 are both closed, and a bridge portion 44 is formed on the outer side in the radial direction. A rectangular parallelepiped magnet (permanent magnet) 45 is accommodated in each magnet mounting hole 43 and fixed by a fixing means such as an adhesive. Adjacent magnets 45 have the same polarity on opposite surfaces. As described above, in the motor 3, a flat permanent magnet that can be easily processed can be used as the magnet 45, so that the number of processing steps can be reduced, the yield can be improved, and the rare earth material can be reduced. A plurality of boss holes 46 for laminating the core plates at predetermined positions are provided in the axial direction on the inner side in the radial direction from the magnet mounting holes 43 by press stamping in the axial direction.

FIG. 4 is an explanatory diagram showing a configuration in the vicinity of the magnet attachment hole 43. In the rotor core 35, the outer periphery between adjacent magnet mounting holes 43 is formed in an outer shape with a radius R. The center O _{1 of the} radius R is eccentrically arranged at a position shifted from the center O of the rotor 22 toward the outer diameter side. A portion having a radius R, that is, a portion between adjacent magnet mounting holes 43 is a pseudo magnetic pole portion 47 in which magnetic fluxes from opposing magnets 45 repel each other and flow radially outward. The number of the pseudo magnetic pole portions 47 is the same as the number of the magnets 45 (here, 14). Since the pseudo magnetic pole portion 47 is eccentrically formed with the radius R as described above, the outer periphery of the rotor core 35 has an uneven shape with the magnet mounting hole 43 portion as a valley and the pseudo magnetic pole portion 47 portion as a mountain. . Accordingly, the pseudo magnetic pole portion 47 is formed in a salient pole shape on the rotor core 35, and a pseudo 14P12S configuration is formed.

  In such EPS1, when the steering wheel 4 is operated and the steering shaft 2 is rotated, the rack shaft is moved in a direction corresponding to the rotation, and a steering operation is performed. By this operation, the torque sensor 11 is activated, and electric power is supplied to the coil 26 from the battery (not shown) via the power supply wiring 48 according to the detected torque. When electric power is supplied to the coil 26, the motor 3 operates, and the rotor shaft 33 and the worm shaft rotate. The rotation of the worm shaft is transmitted to the steering shaft 2 via the worm wheel to assist the steering force.

  FIG. 5 is a block diagram showing the configuration of the control device 50 of the EPS 1, and the control according to the present invention is executed by the control device 50. The control device 50 is provided with a current command unit 51, and the EPS 1 is a detection value from the torque sensor 11 input to the current command unit 51, rotational position information of the rotor 22 detected by the resolver 36, current Drive control is performed based on phase current value information from the sensor 61. In the EPS 1, the advance angle of the motor 3 is controlled in accordance with the motor load information from the torque sensor 11, thereby suppressing torque sagging in a high load region and reducing torque ripple.

  As shown in FIG. 5, a signal corresponding to a torque value that becomes a load of the motor 3 when the handle is operated is input from the torque sensor 11 to the current command unit 51 as motor load information. The torque sensor 11 outputs a signal (voltage) corresponding to the torque value, and the current command unit 51 receives this output signal as motor load information. Further, as described above, the resolver 36 is disposed as an angle sensor in the motor 3, and rotor rotational position information is input from the resolver 36 to the current command unit 51. The rotor rotational position information from the resolver 36 is also input to the rotor rotational speed calculation unit 62 provided in the preceding stage of the current command unit 51.

  The rotor rotation speed calculation unit 62 calculates the rotation speed of the rotor 22 based on the rotor rotation position information. The value calculated by the rotor rotational speed calculation unit 62 is input to the current command unit 51 as rotor rotational speed information. The motor 3 is provided with a current sensor 61 that monitors the supply current of each phase. Each phase current value of the motor 3 is input from the current sensor 61 to the current command unit 51.

  The current command unit 51 is provided with a supply current amount calculation unit 52 that performs arithmetic processing based on these detection values and calculates the amount of current supplied to the motor 3. The supply current amount calculation unit 52 calculates the current command values Id ′ and Iq ′ for the d-axis and the q-axis from the rotor rotation position information and rotor rotation speed information from the resolver 36 and the motor load information, and the vector control unit To 53. At this time, the supply current amount calculation unit 52 calculates the fundamental wave currents Id and Iq indicating the winding current value at which the maximum torque is output according to the load state of the motor 3, and appropriately corrects the advance angle. Current command values Id ′ and Iq ′ are output. The phase current value of the motor 3 is fed back from the current sensor 61 to the supply current amount calculation unit 52. The supply current amount calculation unit 52 performs feedback control on the motor 3 based on the detected current value (phase current).

  The vector control unit 53 includes d-axis and q-axis PI (proportional / integral) control units 54d and 54q, and a coordinate axis conversion unit (dq / UVW) 55, and current command values Id 'and Iq' are , Input to the PI control units 54d and 54q, respectively. Further, the current value of the motor 3 is fed back to the PI control units 54d and 54q, and the three-phase (U, V, W) motor current values are converted to the dq axis via the coordinate axis conversion unit (UVW / dq) 56. The converted detection current values Id and Iq are input. The PI control units 54d and 54q perform PI operation processing based on the current command values Id 'and Iq' and the detected current values Id and Iq, and calculate the d-axis and q-axis voltage command values Vd and Vq. The voltage command values Vd, Vq are input to the coordinate axis converter 55, converted into three-phase (U, V, W) voltage command values Vu, Vv, Vw and output. The voltage command values Vu, Vv, Vw output from the coordinate axis conversion unit 55 are applied to the motor 3 via the inverter 57.

  Here, in the conventional magnetic flux concentration type brushless motor, as described above, there is a problem that torque sagging and torque ripple are caused by the influence of the armature reaction. In this case, in order to alleviate the armature reaction, it is first necessary to make the rotor side difficult to receive the magnetic flux on the field side. Further, in the drive control of the motor, a control mode that mitigates the influence It is preferable to adopt Therefore, in the motor 3, (1) high magnetic flux density by the multi-pole structure and (2) advance angle control alleviate the armature reaction, prevent torque sagging in the high load region, and realize low torque ripple. doing.

(1) High magnetic flux density by multipolar structure From the viewpoint of high magnetic flux density by concentration of magnetic flux, the magnetic flux density increases as the number of magnetic poles increases. However, when the number of poles is increased, the amount of magnets used increases, and the cost increases accordingly. Therefore, considering practicality, about 10P or 14P is realistic. Therefore, the inventors compared both 10P and 14P in the 12S configuration, and obtained the result that the 14P configuration is superior in terms of electromagnetic excitation force acting in the radial direction. FIG. 6 is a graph showing the relationship between torque and electromagnetic force pulsation. Each plot in FIG. 6 is data when the magnet size, radial position, and stator shape (slot opening width and teeth width) are changed. The air gap, motor outer diameter, and magnetic characteristics are the same.

  As can be seen from FIG. 6, the electromagnetic pulsation was clearly smaller in 14P12S than in 10P12S. This is presumably because the magnetic pole of the rotor is small relative to the stator tooth interval, so that the magnetic flux more than necessary does not easily affect the rotor side. The electromagnetic excitation force is a radial force that does not contribute to torque during energization. When electromagnetic force pulsation increases due to electromagnetic excitation force, so-called magnetostriction noise increases and motor operation noise increases. Therefore, by adopting the 14P12S structure like the motor 3, it is possible to reduce the operating noise of the motor and improve the quietness of the EPS1.

(2) Lead angle control In the magnetic flux concentration type brushless motor, the rotor rotational position where the magnetic flux amount should originally be a peak shifts due to the influence of the field due to the armature reaction. Moreover, this deviation becomes remarkable in a high load region (high current region). Therefore, the motor control device 50 corrects the deviation of the sine wave waveform caused by the armature reaction by controlling the energization timing in consideration of the motor load. For this reason, the current command section 51 is provided with an advance angle control map 63, and the advance angle control according to the motor load state is performed based on this map.

  FIG. 7 is an explanatory diagram showing an example of the advance angle control map 63. The supply current amount calculation unit 52 calculates an advance value to be set for the current supplied to the coil 26 based on the advance angle control map 63, and calculates the fundamental currents Id and Iq based on the advance value. Correction is made and current command values Id ′ and Iq ′ are set. In FIG. 7, the horizontal axis indicates the load torque of the motor 3 required for the torque value (output signal: voltage) detected by the torque sensor 11. The vertical axis indicates the advance value to be attached to the motor 3. As shown in FIG. 7, the advance value increases as the load torque increases, that is, as the load on the motor becomes heavier. In general, the advance value increases from the point where the motor torque becomes approximately 1 (Nm). Start angle control. However, it is of course possible to perform advance angle control in the entire torque range, and although an advance angle value of 0.8 (Nm) or less is not shown in FIG. 7, this is not more than 0.8 (Nm). Does not mean that advance angle control is not performed.

  FIG. 8 is an explanatory diagram showing changes in torque and torque ripple with or without such advance angle control. As shown in FIG. 8, when there is no advance angle, the torque begins to sag when the phase current value (here, U phase: Iu) exceeds 50 Apeak. Further, the torque ripple also increases with the current value. On the other hand, when the advance angle control is performed using the advance angle control map as shown in FIG. 7, torque sag does not occur much even if it exceeds 50 Apeak, and the torque ripple changes substantially level. In other words, compared to a conventional magnetic flux concentration type brushless motor, torque sagging is suppressed in a high load region where the output torque decreases with respect to the theoretical torque due to the effect of the armature reaction, and the output is improved. It is suppressed.

  As described above, the EPS motor control method and control apparatus according to the present invention reduces the manufacturing cost by adopting a magnetic flux concentration type motor using a flat magnet, and reduces the armature reaction by increasing the number of pseudo magnetic pole portions. Reduction is achieved. Further, in this multipolarization, by adopting the 14P12S structure, it becomes possible to suppress the magnetostriction noise and reduce the motor operation noise as much as SPM. Further, by performing the advance angle control, it is possible to suppress the torque sagging and improve the output. Further, the torque ripple can be suppressed by the advance angle control, and the steering feeling can be improved. Furthermore, since the control device 50 performs the advance angle control using the advance angle control map 63, the advance angle control of the motor 3 can be performed without imposing a large load on the control device 50.

As mentioned above, it cannot be overemphasized that this invention is not limited to the above embodiment, and can be variously changed in the range which does not deviate from the summary.
For example, in the above-described embodiment, an example in which the present invention is applied to the EPS has been described. The present invention is also applicable to the motor used.

DESCRIPTION OF SYMBOLS 1 Electric power steering apparatus 2 Steering shaft 3 Brushless motor 4 Steering wheel 5 Steering gear box 6 Tie rod 7 Wheel 8 Assist motor part 9 Deceleration mechanism part 11 Torque sensor 12 ECU
21 Stator 22 Rotor 23 Motor Case 24 Stator Core 25 Teeth 26 Stator Coil 26a End 27 Bus Bar Unit 28 Bracket 29 Slot 31 Insulator 32 Feed Terminal 33 Rotor Shaft 34a, 34b Bearing 35 Rotor Core 36 Resolver 37 Resolver Rotor 38 Resolver Stator 39 Resolver Bracket 41 Mounting screw 42 Shaft hole 43 Magnet mounting hole 44 Bridge part 45 Magnet 46 Boss hole 47 Pseudo magnetic pole part 48 Power supply wiring 50 Controller 51 Current command part 52 Supply current amount calculation part 53 Vector control part 54d, 54q PI control part 55 Coordinate axis Conversion unit 56 Coordinate axis conversion unit 57 Inverter 61 Current sensor 62 Rotor rotation speed calculation unit 63 Advance angle control map 71 Rotor 72 Magnet 73 Core member 74 Pseudo magnetic pole O rotor center O ₁ pseudo pole outer diameter center R pseudo pole outside diameter radius

Claims (7)

A plurality of teeth portions projecting radially inward, a plurality of slots formed between the teeth portions, and an induced voltage between the wires wound around the teeth portions via the slots is a sine wave waveform A stator having a multi-phase armature winding,
A core that is rotatably arranged inside the stator and is formed by laminating electromagnetic steel plates, a plurality of magnet housing portions formed radially in the core, and a plurality of housings respectively housed in the magnet housing portions A control method of a brushless motor having a permanent magnet and a rotor provided with a plurality of pseudo magnetic pole portions formed between the magnet housing portions,
A control method for a brushless motor, wherein an advance angle control is performed on the brushless motor based on a load state of the brushless motor. The control method according to claim 1,
The method for controlling a brushless motor, wherein the advance angle control is performed based on a map showing a relationship between a load torque of the brushless motor and the advance angle. The control method according to claim 1 or 2,
The stator includes twelve teeth portions and twelve slots.
The said rotor is provided with 14 said magnet accommodating parts, 14 said magnets, and 14 said pseudo magnetic pole parts, The control method of the brushless motor characterized by the above-mentioned. In the control method according to any one of claims 1 to 3,
The brushless motor is used as a drive source of an electric power steering device,
The electric power steering device has a torque sensor for detecting a load state of the brushless motor,
A lead angle value set for a current supplied to the armature winding is calculated based on a value detected by the torque sensor, and a lead angle control is performed on the brushless motor. Brushless motor control method. Used as a drive source for electric power steering devices,
A plurality of teeth portions projecting radially inward, a plurality of slots formed between the teeth portions, and an induced voltage between the wires wound around the teeth portions via the slots is a sine wave waveform A stator having a multi-phase armature winding,
A core that is rotatably arranged inside the stator and is formed by laminating electromagnetic steel plates, a plurality of magnet housing portions formed radially in the core, and a plurality of housings respectively housed in the magnet housing portions A control device for a brushless motor having a permanent magnet and a rotor including a plurality of pseudo magnetic pole portions formed between the magnet housing portions,
The electric power steering device has a torque sensor that detects a load state of the brushless motor,
The control device calculates an advance value to be set for a current supplied to the armature winding based on a load state of the brushless motor detected by the torque sensor, and for the brushless motor A control device for a brushless motor for an electric power steering apparatus, comprising a supply current amount calculation unit for performing advance angle control. The control device according to claim 5,
The control device further includes a map showing a relationship between a load torque of the brushless motor and the advance angle;
The controller for a brushless motor for an electric power steering apparatus, wherein the supply current amount calculating unit calculates the advance value based on the map. The control device according to claim 5 or 6,
The stator includes twelve teeth portions and twelve slots.
The said rotor is provided with 14 said magnet accommodating parts, 14 said magnets, and 14 said pseudo magnetic pole parts, The control apparatus of the brushless motor for electric power steering apparatuses characterized by the above-mentioned.

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