JP4501683B2 - Permanent magnet rotating electrical machine, on-vehicle electric actuator device electric system using the same, and electric power steering device electric system - Google Patents

Description

  The present invention relates to a permanent magnet rotating electric machine, an on-vehicle electric actuator device electric system using the same, and an electric power steering device.

  Cars are being electrified in order to reduce fuel consumption and improve operability. Compared to the conventional hydraulic system that always consumes drive energy, there is a tendency to adopt an electric system that consumes drive energy only when necessary. Typical examples include a throttle actuator, a brake device, a power steering device, an automatic transmission device, and the like that control the amount of air. Conventionally, a direct current machine has been mainly used as the rotating electrical machine used here, but concentrated winding permanent magnet rotating electrical machines are being used from the viewpoint of miniaturization.

  In this type of concentrated winding permanent magnet rotating electrical machine, it is small and lightweight from the viewpoint of mounting spacers, high efficiency to ensure operating time at high load, and low cogging torque to improve operability Is required. On the other hand, the structure selection of the concentrated winding permanent magnet rotating electric machine can be realized by concentrated winding, the use of a split core, or the appropriate selection of the number of permanent magnet poles and the number of salient poles. As background art of this type of permanent magnet rotating electric machine, for example, those disclosed in Patent Documents 1 and 2 are known.

  In these patent documents, the end coil length can be shortened by concentrated winding, and the cogging torque and magnet eddy current can be reduced by appropriately selecting the number of poles and salient poles of the permanent magnet. It is disclosed that a permanent magnet rotating electrical machine with improved space factor can be obtained by using divided magnetic poles.

JP 2000-236638 A JP 2003-250254 A

  With the above method, it is possible to realize a concentrated winding permanent magnet rotating electric machine with a certain size and weight reduction, high efficiency, and small cogging torque, but new pulsation torque is generated especially by dividing the fixed core. Among the on-vehicle electric actuator devices, particularly, the electric power steering device senses a slight torque pulsation due to manual operation, resulting in poor operability. This torque pulsation can be reduced by having a very small level and improving the manufacturing accuracy, but it is necessary to improve the accuracy of each dimension of the component parts. For this reason, there existed a subject that productivity was impaired.

  The present invention provides a permanent magnet rotating electrical machine capable of reducing torque pulsation caused by manufacturing errors.

  A typical feature of the present invention is that the stator or rotor has an order lower than the number of salient poles or rotating magnetic poles, and corrects magnetic imbalance of the stator or rotor. The correction means is provided.

  The present invention also provides an on-vehicle electric actuator device electrical system including the permanent magnet rotating electrical machine.

  Furthermore, the present invention provides an electric machine system for an electric power steering apparatus provided with the permanent magnet rotating electric machine.

  According to the present invention, torque pulsation caused by manufacturing errors can be reduced, so that the productivity of the permanent magnet rotating electrical machine is not impaired by improving the accuracy of each dimension of the component parts. Therefore, according to the present invention, a permanent magnet rotating electrical machine that is small, light, highly efficient and excellent in operability can be provided at low cost.

  Further, according to the present invention, it is possible to provide an on-vehicle electric actuator device electrical system including the permanent magnet rotating electrical machine.

  Furthermore, according to the present invention, an electric system for an electric power steering apparatus provided with the permanent magnet rotating electric machine can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  The permanent magnet rotating electrical machine of the present invention is suitable as an electric motor applied to an on-vehicle electric actuator device electrical system. In the following description, an electric power steering device will be described as an example of the on-vehicle electric actuator device.

  First, the schematic configuration of the electric power steering apparatus of the present embodiment will be described with reference to FIG.

  FIG. 6 shows a system configuration of the electric power steering apparatus of the present embodiment.

  An electric power steering apparatus (hereinafter referred to as “EPS”) 100 of the present embodiment is a column type EPS that assists the steering shaft by providing the permanent magnet rotating electrical machine 1 in the vicinity of the steering shaft (column).

  The EPS includes a pinion type EPS that assists the pinion gear by providing a motor in the vicinity of the rack and pinion gear, and a rack cross type EPS that assists the rack by providing a motor in the vicinity of the rack and pinion gear. The permanent magnet rotating electrical machine 1 of the present embodiment can also be applied to those EPS.

  When the driver rotates the steering wheel (handle) 101, the main steering force (rotational force) is transmitted to the rack and pinion gear 107 via the steering shaft 102. Further, an auxiliary steering force (rotational force) output from the permanent magnet rotating electrical machine 1 is transmitted to the steering shaft 102 via the speed reducer 104.

  The rack and pinion gear 107 is a mechanism that converts the input main steering force (rotational force) and auxiliary steering force (rotational force) into a linear reciprocating force and transmits it to the left and right tie rods. It comprises a shaft (all not shown) and a pinion shaft (not shown) on which a pinion gear is formed. The rack gear and the pinion gear mesh with each other in a power converter (not shown), and the rotational force is converted into a linear reciprocating force.

  The steering force converted into the linear reciprocating force in the rack and pinion gear 107 is transmitted to the left and right tie rods connected to the rack shaft, and is transmitted from the left and right tie rods to the left and right wheels. Thereby, the left and right wheels are steered.

  A torque sensor 103 is provided on the steering shaft 102. The torque sensor 103 is for detecting a steering force (rotational torque) applied to the steering wheel 101.

  The permanent magnet rotating electrical machine 1 is controlled by a control device 105. The permanent magnet rotating electrical machine 1 and the control device 105 constitute an EPS actuator (electrical system). EPS uses a vehicle-mounted battery 106 as a power source. The control device 105 is an inverter device that converts the DC power supplied from the battery 106 into multiphase AC power so that the output torque of the permanent magnet rotating electrical machine 1 becomes the target torque based on the output of the torque sensor 103. And supplied to the permanent magnet rotating electrical machine 1.

  In the present embodiment, since the cogging torque is small, the light weight and the high efficiency concentrated winding type permanent magnet rotating electric machine 1 is used for the EPS, a compact EPS with good operability can be provided.

  Next, the electrical connection relationship of the electric actuator (electrical system) used in the EPS of this embodiment will be described with reference to FIG.

  FIG. 5 shows an electrical circuit configuration of an electric actuator (electrical system) used in the EPS of this embodiment.

  The control device 105 includes a power module 16 that constitutes an inverter main circuit (conversion circuit), and a control module 22 that controls an on / off operation (switching operation) of a power semiconductor switching element of the power module 16. The inverter main circuit of the power module 16 is composed of a three-phase bridge circuit configured by bridge-connecting six power semiconductor switching elements. The battery 106 is electrically connected to the input side (DC side) of the inverter main circuit of the power module 16, and the armature winding 5 of the permanent magnet rotating electrical machine 1 is electrically connected to the output side (AC side). By controlling the switching of each of the six power semiconductor switching elements of the power module 16 by the control module 22, the DC power output from the battery 106 is converted into three-phase AC power in the inverter main circuit of the power module 16, It is supplied to the armature winding 5 of the permanent magnet rotating electrical machine 1.

  The control module 22 generates a control signal for controlling the on / off operation (switching operation) of the power semiconductor switching element, and configures a control unit that outputs the control signal to a driver circuit (not shown) of the power module 16. is doing. The control module 16 receives as input parameters the torque detection value Tf of the steering wheel 101 detected by the torque sensor 103, the rotation speed detection value of the rotor 3 detected by the encoder E, and converted by the F / V converter 18. ωf and the magnetic pole position detection value θm of the rotor 3 detected by the resolver PS are input.

The torque detection value Tf is input to the torque control circuit 17 together with the torque command value Ts. The torque control circuit 17 calculates a torque target value Te based on the detected torque value Tf and the torque command value Ts, and outputs a current command value Is and a rotation angle θ1 by proportional integration of the calculated torque target value Te. . The rotation angle θ1 is input to the phase shift circuit 23 together with the position information θ output from the encoder E. The phase shift circuit 23 shifts the phase information θ of the rotor 3 according to the command of the rotation angle θ1 and outputs it as the rotation angle θa. The rotation angle θa is input to the sine wave / cosine wave generation circuit 19 together with the magnetic pole position detection value θm. The sine wave / cosine wave generating circuit 19 is a sine wave basic waveform (in which the induced voltage of each phase winding (here, three phases) of the armature winding 5 is phase-shifted based on the rotation angle θa and the magnetic pole position detection value θm. Drive current waveform) A value Iav is generated and output. The phase shift amount may be zero.

The sine wave basic waveform (drive current waveform) value Iav is input to the two-phase / three-phase conversion circuit 20 together with the current command value Is. The two-phase / three-phase conversion circuit 20 outputs current commands Isa, Isb, Isc corresponding to each phase based on the sine wave basic waveform (drive current waveform) value Iav and the current command Is. The control module 22 includes current control systems 21A, 21B, and 21C for each phase. The current control systems 21A, 21B, and 21C for each phase are supplied with the current commands Isa, Isb, and Isc for the corresponding phases and the current detection values Ifa, Ifb, and Ifc for the corresponding phases. The current detection values Ifa, Ifb, Ifc are detected by the current detector CT, and are phase currents supplied from the conversion circuit of the power module 16 to the armature winding 5 of each phase. The current control systems 21A, 21B, and 21C for the respective phases are based on the current commands Isa, Isb, and Isc for the corresponding phases and the detected current values Ifa, Ifb, and Ifc for the corresponding phases. A control signal for controlling the switching operation is output. The control signal for each phase is input to the corresponding driver circuit (not shown) of the power module 16.

  A driver circuit (not shown) of each phase of the power module 16 outputs a drive signal for switching the power semiconductor switching element of the corresponding phase based on the control signal of the corresponding phase. The drive signal for each phase is input to the power semiconductor switching element for the corresponding phase. When the power semiconductor switching element performs a switching operation, the DC power supplied from the battery 106 is converted into AC power and supplied to the armature winding 5. The permanent magnet rotating electrical machine 1 generates a rotating magnetic field corresponding to the rotational position of the rotor 3 and the rotor 3 rotates.

  The combined current of each phase current supplied to the armature winding 5 is a position that is orthogonal or phase-shifted to the field magnetic flux (the control that advances the combined magnetomotive force of each phase current by 90 degrees or more from the permanent magnet is referred to as field weakening control). ) Always formed. Thereby, it is a commutator-less and can obtain the characteristic equivalent to a DC machine.

  A maximum torque is generated by creating a combined vector of armature magnetomotive force generated by the current flowing through the armature winding 5 by the control device 105 at a position 90 degrees from the center of the permanent magnet, and the phase is shifted as necessary. By doing so, it can be rotated to a high speed.

  By such control, the output (torque) generated by the three-phase sine wave induced voltage and the three-phase sine wave current can be obtained without a pulsation regardless of the rotation.

  Next, the permanent magnet rotating electrical machine used in the EPS of this embodiment will be described in detail with reference to FIGS.

  1 and 2 show the overall configuration of a permanent magnet rotating electric machine used in the EPS of this embodiment.

The permanent magnet rotating electrical machine 1 according to the present embodiment uses a vehicle-mounted battery (for example, an output voltage of 12 V) as a power source, and is disposed in the vicinity of the steering shaft. Therefore, it is necessary to reduce the size because of the limitation of the mounting position, and it is necessary to output a large torque (for example, 4. Nm) because the steering is power-assisted.

  The permanent magnet rotating electrical machine 1 is a surface magnet type synchronous motor including a stator 2 and a rotor 3 rotatably supported inside the stator 2. The permanent magnet rotating electrical machine 1 is driven by electric power supplied from a 14-volt power supply (battery having an output voltage of 12 volts). In-vehicle power supplies include 24-volt power supplies, 42-volt power supplies (battery output voltage 36 volts), or 48-volt power supplies, and the drive power supply voltage of the permanent magnet rotating electrical machine 1 varies depending on the type of automobile. The EPS of this embodiment is compatible with any of the above power sources.

The stator 2 includes a stator core 4 formed of a magnetic substance laminated with a silicon steel plate, and an armature winding 5 held in the slots of the stator core 4. The stator core 4 includes an annular stator yoke 41, and the stator yoke 41 is made to separate, then, a plurality of salient magnetic pole cores 42 which is mechanically fixed to the stator yoke 41 Composed. An armature winding 5 is wound around each of the salient pole magnetic cores 42. The armature winding 5 is wound by a distributed winding method or a concentrated winding method.

  When the armature winding 5 is a distributed winding, the field weakening control is excellent, and the generation of reluctance torque is also excellent. As the permanent magnet rotating electric machine 1, it is very important to reduce the motor size and the winding resistance. By making the armature winding 5 concentrated, the coil end length of the armature winding 5 can be shortened. Thereby, the length of the rotation direction of the permanent magnet rotating electrical machine 1 can be shortened. Moreover, since the length of the coil end of the armature winding 5 can be shortened, the resistance of the armature winding 5 can be reduced, and the temperature rise of the motor can be suppressed. Further, since the coil resistance can be reduced, the copper loss of the motor can be reduced. Therefore, the ratio consumed by the copper loss in the input energy to the motor can be reduced, and the efficiency of the output torque with respect to the input energy can be improved.

  The permanent magnet rotating electrical machine 1 may be placed near the steering shaft (column) or near the rack and pinion. Further, it is necessary to fix the armature winding with a miniaturized structure, and it is also important that the winding work is easy. Concentrated winding is easier to wind and fix the winding than distributed winding.

The armature winding 5 is composed of three phases of U phase, V phase, and W phase, each composed of a plurality of unit coils. The plurality of unit coils are connected by a connection ring 11 formed of a plate-like conductor for each of the three phases in the coil end portion.

  The permanent magnet rotating electrical machine 1 is required to have a large torque. For example, when the steering wheel (handle) is rapidly rotated in a driving stop state or a driving state close to the stop of driving, a large torque is required for the motor due to frictional resistance between the steering wheel and the ground. At this time, a large current is supplied to the stator coil. This current varies depending on conditions, but a current of 100 amperes or more flows. In order to supply such a large current safely and to reduce heat generation due to the current, it is very important to use the connection ring 11 formed of a plate-like conductor. By supplying current to the armature winding 5 via the connection ring 11, the connection resistance can be reduced, and the voltage drop due to copper loss can be suppressed. This facilitates the supply of a large current. Further, there is an effect that the rising time constant of the current accompanying the operation of the inverter element is reduced.

  The rotor 3 includes a rotor core 7 made of a magnetic material in which silicon steel plates are laminated, and permanent magnet pieces 6 that are a plurality of permanent magnets fixed to the surface of the rotor core 7 with an adhesive. The permanent magnet piece 6 is a rare earth magnet, and is made of, for example, neodymium. The rotor core 7 is fixed to the shaft 8. In order to prevent the permanent magnet pieces 6 from scattering, a magnet cover may be provided or a tape may be wound around the permanent magnet pieces 6 so as to cover the entire outer circumference side (stator side).

  The stator core 4 is supported and fixed so as to be sandwiched by cup-shaped brackets 9 from both axial sides. The bracket 9 is provided with a bearing 10. The bearing 10 rotatably supports the shaft 8. A resolver PS for detecting the position of the rotor 3 and an encoder E are provided on the shaft 8.

  Power is supplied from an external battery to the U-phase, V-phase, and W-phase connected by the connection ring 11 via a power cable.

  The configurations of the stator 2 and the rotor 3 will be described more specifically.

  The stator core 4 includes an annular stator yoke 41 and a plurality of salient pole magnetic cores 42 that are separated from the stator yoke 41. The stator yoke 41 has a configuration in which a thin magnetic plate such as a silicon steel plate is punched out by press molding and laminated.

In this embodiment, the salient pole magnetic core 42 is composed of 12 independent salient pole magnetic cores 42. Corresponding phases of armature windings 5 are wound around each salient pole magnetic core in a concentrated manner. U-phase armature windings 5 are U1 +, U1-, U2 +, U2-. The V-phase armature winding 5 is V1 +, V1-, V2 +, V2-. W-phase armature winding 5 is W1 +,
W1-, W2 +, W2-. The subscript 1 indicates the armature winding number. +-Indicates the winding direction of the armature winding.

Here, U1 + of the armature winding 5 and U1- of the armature winding 5 are wound such that the direction of the current flowing through the coil is opposite. Both U2 + of the armature winding 5 and U2- of the armature winding 5 are wound so that the direction of the current flowing through the coil is opposite. Moreover, U1 + of the armature winding 5 and U2 + of the armature winding 5 are wound so that the directions of currents flowing through the coils are the same direction. Both U1- of the armature winding 5 and U2- of the armature winding 5 are wound so that the directions of the currents flowing through the coils are the same direction. The other-phase armature winding 5 is the same as in the U-phase.

In the permanent magnet rotating electrical machine 1 of this embodiment, among the armature windings 5 in one phase, for example, U1 +, U1-, U2 +, U2- for the U phase, V1 +, V1-, V2 +, V2- for the V phase, The W phase is characterized in that at least one of the phases of the armature winding 5 composed of W1 +, W1-, W2 +, W2- is different from the permanent magnet rotor. In the figure, the U phase has a phase difference of 180 + 30 in electrical angle between U1 + and U1-, and 30 degrees in electrical angle between U1 + and U2- armature winding 5, and U1 + and U2- armature winding. Between the lines 5, the electrical angle has a phase difference of 180 degrees.

  Incidentally, in the permanent magnet rotating electrical machine of this embodiment of the present configuration, the number of pulsations per rotation of the cogging torque is 60 and the winding coefficient is 0.933. For example, a salient pole is a salient pole with a concentrated winding stator that is often used in the industry. The number of poles of the permanent magnet rotor is 12, and the pulsation per rotation of the cogging torque in the case of the permanent magnet rotating electric machine of 24 is 24 and the winding coefficient is 0.886. In the magnet rotor electric machine, the number of pulsations per rotation of the cogging torque is high, and the winding coefficient can be increased. The cogging torque is small against the number of pulsations per rotation under the same conditions, and the torque increases substantially according to the winding coefficient. Therefore, the cogging torque is a low cogging torque, small and light, and highly efficient permanent magnet rotating electric machine. With such a configuration, for example, a rotary electric machine suitable for an electric power steering can be used as an actuator for an automobile.

  Since the twelve salient pole magnetic cores 42 and the armature winding 5 are manufactured in the same manner, here, U1 + of the salient pole magnetic core 42 and U1 + of the armature winding 5 are taken as an example for the assembly process. explain. U1 + of the armature winding 5 is a formed coil that is formed in advance so as to have a shape wound around U1 + of the salient pole magnetic core 42. U1 + of the armature winding 5 serving as the formed coil is formed together with the bobbin. A bobbin and the U1 + integrated body of the armature winding 5 formed are fitted from the rear end side of the salient pole magnetic core 42 U1 +. Since the tip of U1 + of salient pole magnetic core 42, that is, the side facing rotor 3, is enlarged in the circumferential direction, bobbin and armature winding 5 serve as a stopper and are locked at this enlarged portion. . On the rear end side of the U1 + of the salient pole magnetic core 42, a recess formed on the inner peripheral side of the stator yoke 41 and a convex eye-shaped projection are formed. The U1 + convex portion of the salient pole magnetic core 42 around which the U1 + of the molded armature winding 5 is wound is press-fitted into the concave portion of the stator yoke 41, and the U1 + of the salient pole magnetic core 42 is fixed to the stator yoke 41. Fixed to. The same applies to the other salient pole magnetic cores 42 and armature windings 5.

  U1 +, U1- and U2 +, U2- of the U-phase armature winding 5 are arranged symmetrically with respect to the center of the stator 2. That is, U1 + of the armature winding 5 and U1- of the armature winding 5 are arranged adjacent to each other, and U2 + of the armature winding 5 and U2- of the armature winding 5 are arranged adjacent to each other. Furthermore, U1 +, U1- of the armature winding 5 and U2 +, U2- of the armature winding 5 are arranged symmetrically with respect to the center of the stator 2. That is, U1 + of the armature winding 5 and U2- of the armature winding 5 are arranged symmetrically with respect to the center line of the shaft 8, and U1- of the armature winding 5 and U2 + of the armature winding 5 are arranged. And are arranged in line symmetry. The other-phase armature windings 5 are similarly arranged.

The adjacent armature windings 5 having the same phase are wound continuously by one wire. That is, U1 + of the armature winding 5 and U1- of the armature winding 5 are formed by winding a single wire continuously to form two winding coils, which are inserted into the salient pole magnetic core 42, respectively. Thus, the salient pole magnetic core 42 is wound around. U2 + of the armature winding 5 and U2- of the armature winding 5 are also wound continuously by one line. V1 + of armature winding 5 and V1- of armature winding 5, V2 + of armature winding 5 and V2- of armature winding 5, W1 + of armature winding 5 and W1- of armature winding 5 , W2 + of the armature winding 5 and W2- of the armature winding 5 are also wound continuously by one line.

  Such a line symmetrical arrangement and winding of two adjacent in-phase coils with one wire make it possible to simplify the configuration of the connection ring 11 when connecting each phase or different phases with the connection ring 11. Can be.

  The rotor 3 includes a rotor core 7 made of a magnetic material and ten permanent magnet pieces 6 (N1 to N5, S1 to S5) fixed to the surface of the rotor core 7 with an adhesive. The rotor core 7 is fixed to the shaft 8.

  The permanent magnet piece 6 (N1 to N5) has an N pole on the front surface side (side facing the salient pole magnetic core 42 of the stator), and the rear surface side (side bonded to the rotor core 7) is the S pole. So that it is magnetized in the radial direction. Further, the permanent magnet piece 6 (S1 to S5) has a back surface (side bonded to the rotor core 7) when its front surface side (side facing the salient pole magnetic core 42 of the stator) is S pole. Some are magnetized in the radial direction so as to have N poles. The adjacent permanent magnet pieces 6 are magnetized so that the magnetized polarities are alternately arranged in the circumferential direction. For example, if the N1 surface side of the permanent magnet piece 6 is magnetized to the N pole, the surface sides of S1 and S5 of the adjacent permanent magnet pieces 6 are magnetized to the S pole.

As described above, the rotor 3 of this embodiment includes ten permanent magnet pieces 6.
10 poles. As described above, the number of salient pole magnetic cores 42 is twelve, and the number of slots formed between adjacent salient pole magnetic cores 42 is twelve. That is, the permanent magnet rotating electrical machine 1 of the present embodiment is a surface magnet type synchronous motor having 10 poles and 12 slots.

In the adjacent salient pole magnetic cores 42, the distance between the enlarged portions of the tips (sides facing the rotor 3) of the salient pole magnetic cores 42 (for example, U1- of the salient pole magnetic core 42 and W2- of the salient pole magnetic core 42). The interval between the enlarged portions at the tip of the (the interval in the circumferential direction of the portion closest to the circumferential direction) is 1 mm. Thus, the cogging torque can be reduced by narrowing the interval between the salient pole magnetic cores 42. In addition, even if vibration is applied to the motor, the armature winding 5 is thicker than the interval, so that it is possible to prevent the armature winding 5 from falling to the rotor side from between the salient pole magnetic cores 42. The interval between adjacent salient pole magnetic cores 42 is, for example, 0.5 which is equal to or smaller than the wire diameter of the armature winding 5.
mm to 1.5 mm are preferred. Thus, in this embodiment, the interval between the adjacent salient pole magnetic cores 42 is set to be equal to or smaller than the wire diameter of the armature winding 5.

  In the armature winding 5 of this embodiment, the U phase, V phase, and W phase are delta (Δ) connections. Each phase constitutes a parallel circuit. In other words, in view of the U phase, the series circuit of U2 + and U2- of the armature winding 5 is connected in parallel to the series circuit of U1 + and U1- of the armature winding 5. Here, U1 + and U1- of the armature winding 5 constitute a coil by continuously winding one wire as described above. The same applies to the V phase and the W phase.

  Although the star connection can be used as the connection method, the terminal voltage can be lowered by using the delta connection as compared with the star connection. For example, when the voltage across the U-phase series-parallel circuit is E, the terminal voltage is E, but in the star connection, it is √3E. Since the terminal voltage can be lowered, the number of turns of the coil can be increased and a thin wire can be used. In addition, by using a parallel circuit, it is possible to use a wire with a small wire diameter from the viewpoint that the current flowing through each coil can be reduced compared to the case where four coils are connected in series, so that the space factor is increased. It is easy to bend and the manufacturability is good.

  U1-, U2-, V1 +, V2 + of the armature winding 5 are electrically connected by a connection ring 11. Similarly, V1-, V2-, W1 +, W2 + of the armature winding 5 are also electrically connected by the connection ring 11. Similarly, U1 +, U2 +, W1-, W2- of the armature winding 5 are electrically connected by the connection ring 11. If it connects as mentioned above, it can be set as a three-phase delta connection.

  The permanent magnet rotating electrical machine 1 generates a rotating magnetic field by applying a three-phase current to the armature winding 5 in accordance with the resolver PS that detects the position of the rotor 3 and the rotor position detected by the encoder E. . A magnetic attraction and repulsive force is generated between the rotating magnetic field and the permanent magnet field of the rotor 3 to generate a continuous rotating force. Here, it is possible to operate with the maximum torque by appropriately selecting the phase of the current.

  The stator yoke 41 and the salient pole magnetic core 42 constituting the stator core 4 are individually divided as shown in the figure. Further, the stator yoke 41 may be divided into a plurality of parts in the circumferential direction as necessary. Thus, by using the split iron core, the armature windings 5 can be wound in an aligned manner, and the concentrated winding permanent magnet rotating electric machine can be reduced in size and weight by using a high space factor winding.

  By dividing the stator core 4 by the stator yoke 41 and the salient pole magnetic core 42 as shown in the figure, the space factor of the stator winding can be increased, and a small, lightweight and highly efficient motor can be obtained.

  However, on the other hand, due to manufacturing errors such as the gap between the salient pole magnetic core 42 and the stator yoke 41, or the length of the salient pole magnetic poles, the core circularity of the stator inner diameter deteriorates and cogging torque, pulsation Torque is generated. Since the cogging torque and pulsation torque are different from general pulsation torque, the magnitude and phase are different for each motor, so that prevention is very difficult.

  For example, as shown in FIG. 1, when the surface of the salient pole magnetic core 42 wound with the U1 + armature winding 5 jumps to another salient pole magnetic core 42 as shown, The rotation generates a cogging torque of a cycle corresponding to the number of poles 10 of the permanent magnet. This is a much larger value than the cogging torque of 60 cycles / rotation caused by the number of poles of the permanent magnet and the salient pole magnetic core 42 described above. Among the in-vehicle actuator devices, particularly in the electric power steering device, the pulsation is transmitted to the driver via the handle.

  On the other hand, when one of the segment-like permanent magnet pieces 6 becomes thick as shown by S3, for example, the rotor 3 has a cogging torque corresponding to the number 12 of salient pole magnetic cores 42 per one rotation. This value is also much larger than the cogging torque of 60 cycles / rotation.

  Here, the cogging torque generated in the permanent magnet rotating electric machine will be described. FIG. 3 shows a waveform of cogging torque generated in the permanent magnet rotating electric machine. (A) shows the cogging torque waveform, and (b) shows the frequency analysis result.

  When the permanent magnet of the permanent magnet rotating electrical machine 1 has a segment structure and is individually bonded to each pole, the accuracy cannot be ensured. Therefore, a cogging torque having a cycle of 12 stator salient poles per rotation is generated. . On the other hand, when the salient pole magnetic core 42 is formed separately from the stator yoke 41 as shown in the figure, the number of permanent magnet poles per rotation is 10 per rotation depending on the core circularity of the inner diameter of the stator magnetic pole. A cogging torque having a cycle to be generated is generated.

Therefore, as shown in FIG. 1, for example, the magnetic unbalance of the stator having a weight that generates a cogging torque opposite in phase to the cogging torque shown in FIG. By providing the groove 42a on the surface facing the rotor 3 in consideration of the magnitude of the cogging torque, it is possible to compensate for the cogging torque generated by the manufacturing by post-processing.

  Using the same principle, the cogging torque of the number of stator salient poles per rotation caused by imbalance in the attachment of the permanent magnet piece 6 is also the magnetic pole surface of the permanent magnet piece 6 (surface facing the stator 2). It is possible to guarantee by providing the groove 6a in consideration of the cogging torque.

  This is the same as the balancing operation in the rotating body, and is a method of adjusting the imbalance associated with assembly and processing in the final process rather than dealing with imbalances on a component basis.

  In this embodiment, by correcting the magnetic imbalance caused by the above-described division method after the stator 2 is assembled, the pulsation torque can be sufficiently reduced without increasing individual accuracy at the time of manufacture, thereby reducing the cost. The permanent magnet rotating electrical machine 1 can be provided.

  In this correction, the magnetic unbalance amount is measured after the stator 2 is assembled, and the corresponding magnetic unbalance amount can be removed by, for example, cutting.

  The groove 42a is a non-magnetic portion (magnetic gap) for adjusting the magnetic flux passing through the salient pole magnetic core 42, and the magnetic pole center on the surface of the salient pole magnetic core 42 facing the rotor 3 is cut out by cutting. This is a notch provided.

  Although the stator 2 has been described above, the same applies to the case of the rotor 3.

  In the case of a segment magnet corresponding to the number of poles of the rotor 3, the amount of magnetic unbalance of the permanent magnet piece 6 varies depending on the variation in the bonding position of each permanent magnet piece 6 and the thickness of the permanent magnet piece 6. come. Even in this case, after the rotor 3 is assembled, the magnetic unbalance can be corrected by measuring the magnetic unbalance amount and cutting the surface of the permanent magnet piece 6.

  The groove 6a is a non-magnetic part (magnetic gap) for adjusting the amount of magnetic flux of the permanent magnet piece 6, and is provided by cutting the magnetic center of the surface of the permanent magnet piece 6 facing the stator 2 by cutting. It is a notch. Further, the number of grooves 6a is smaller than the number of permanent magnet pieces 6.

  In this case, it can be manufactured without increasing the adhesion accuracy of the magnet, and a permanent magnet rotating electrical machine with a small pulsating torque can be provided at low cost.

  FIG. 3 also shows the cogging torque waveform in which the 10-cycle component and the 12-cycle component per rotation of the permanent magnet rotating electrical machine 1 of this embodiment are completely taken into account. As is apparent from FIG. 3, the cogging torque is greatly reduced in the permanent magnet rotating electrical machine 1 of this embodiment in which the magnetic imbalance is corrected.

  Next, magnetic unbalance correction according to the present embodiment will be described with reference to FIG.

  FIG. 4 shows the magnetic unbalance correction apparatus of this embodiment.

The permanent magnet rotating electrical machine 1 is driven at a constant speed at a low speed by a drive motor 12. A torque detector 13 outputs a measured value of cogging torque. Further, the resolver PS and encoder E for detecting the rotation position can output the phase together with the magnitude of the cogging torque. Reference numeral 14 denotes a magnetic unbalance amount calculation device which corrects the phase based on the measurement result of the cogging torque from the permanent magnet rotating electrical machine 1 and the phase and size of the groove 42a on the surface of the salient pole magnetic core 42 or the permanent magnet piece 6. The phase and size of the surface groove 6a are calculated from the shape of the stator and rotor, and the characteristics of the permanent magnet, and the amount of correction of the magnetic imbalance is calculated. In a motor having a large cogging torque, the cogging torque can be reduced by providing the rotor 3 with the groove 6a corresponding to the magnetic imbalance. By performing the motor of the total number, for example, the cogging torque correction intends it possible line in the same manner as taking all the rotational balance, which makes it possible to provide a small motor cogging torque. Moreover, it is also possible to correct only a motor having a large cogging torque as necessary.

  As described above, in the present embodiment, the method of correcting by providing a groove on the gap surface between the stator 2 and the rotor 3 has been described. However, it is also possible to attach a magnetic material to a groove provided in advance. Needless to say. Further, correction can also be made by adding and removing the magnetic material to and from the air gap surface and its periphery, or adding and removing the magnetic material by other methods. Further, if necessary, the magnetic field calculation is used to calculate the stator magnetic correction amount and the rotor magnetic correction amount that make the cogging torque detected by the 13 torque sensors zero, and the accuracy can be further improved.

  In this embodiment, the number of salient pole magnetic poles is 12 and the number of poles of the rotor 3 is 10 in the concentrated winding stator, that is, the ratio of the salient pole magnetic pole number M and the rotor pole number P is M: P = 6n: 6n ± 2 (where n is a positive integer) has been described as a permanent magnet rotating electric machine. However, the present invention is not limited to this, and the number of salient poles M and the number P of the rotor 3 It is also applicable to a permanent magnet rotating electrical machine in which the ratio of M: P = 3n: 3n ± 1 (n is a positive integer). For example, the number of poles of the permanent magnet can be set to 8, and the number of salient poles of the stator can be set to 9.

  Similar cogging torque correction can also be performed by selecting the so-called 3: 2 magnetic poles where the number of salient poles is 12 and the number of salient poles is 8, depending on the position of the groove on the surface of the salient pole pole. In this case, the cogging torque can be minimized by disposing a groove of an appropriate size not at the center of the salient pole magnetic pole surface but at a specific position of the salient pole magnetic pole where the cogging torque can be reduced.

Further, the cogging torque due to the difference between the salient pole magnetic core 42 wound with the U1 + armature winding 5 and the other permanent magnet piece 6 and the salient pole magnetic core 42 due to S3 of the permanent magnet piece 6 shown in FIG. In addition to affecting the induced voltage, it also causes pulsating torque. On the other hand, the groove 6a on N1 of the permanent magnet piece 6 of this embodiment and the groove 42a of the salient pole magnetic core 42 also have an effect of relaxing the pulsating torque.

  Next, another example of the permanent magnet rotating electric machine will be described with reference to FIG.

  FIG. 7 shows a configuration of another example of a permanent magnet rotating electrical machine.

  In the example of FIG. 1, a new groove is provided for correcting the cogging torque. On the other hand, in the example of FIG. 7, a groove 42 a is provided in advance on the surface of the salient pole magnetic core 42 of the stator 3. In the permanent magnet rotating electric machine having a large cogging torque, the magnitude and phase of the cogging torque are obtained by the measuring device shown in FIG. 4, and the magnitude of the magnitude in the groove 42a on the surface of the salient pole magnetic core 42 corresponding to the cogging torque is obtained. The cogging torque can be minimized by inserting the compensation iron piece 42b corresponding to the required length in the axial direction.

  Similarly, in the rotor 3, for example, an inner core type rotor 3 in which the permanent magnet piece 6 is disposed in a silicon steel plate, and the rotor core stator on the outer side (stator side) of the permanent magnet piece 6 The groove 6 a is provided in advance at a portion corresponding to the center of the magnetic pole of the permanent magnet piece 6. Further, by using the measuring apparatus shown in FIG. 4, the compensation iron piece 6b is inserted into the groove 6a on the surface of the rotor core 7 by a required axial length according to the magnitude and phase of the obtained cogging torque. Cogging torque can be minimized. The compensation iron piece 6b may be made of a solid resin containing magnetic text. In this example, the permanent magnets N2 and S2 are provided on the surface. As a result, the cogging torque can be made sufficiently small.

  As described above, in the present embodiment, the case where the concentrated winding permanent magnet rotating electric machine of the present embodiment is used for the electric power steering apparatus has been described. By using the concentrated winding permanent magnet rotating electrical machine of the present embodiment in a device to be positioned using the wound permanent magnet rotating electrical machine, such as an electric throttle device, an automatic transmission device, an electric brake device, etc., the positioning accuracy is improved. The system performance can be improved and the system can be reduced in size and weight.

Sectional drawing which shows the structure of the permanent magnet rotary electric machine which is an Example of this invention. Sectional drawing which shows the structure of the permanent magnet rotary electric machine which is an Example of this invention. It is a characteristic view which shows the characteristic of the permanent magnet rotary electric machine which is an Example of this invention, (a) shows a cogging torque waveform, (b) shows the frequency analysis result of (a), respectively. The top view which shows the structure of the magnetic imbalance amount correction | amendment apparatus of the permanent magnet rotary electric machine which is an Example of this invention. The circuit diagram which shows the structure of the control circuit of the permanent magnet rotary electric machine of FIG. The block diagram which shows the structure of the electric power steering apparatus which mounts the permanent magnet rotary electric machine of FIG. Sectional drawing which shows the structure of the permanent magnet rotary electric machine which is another Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Permanent magnet rotary electric machine, 2 ... Stator, 3 ... Rotor, 4 ... Stator iron core, 5 ... Armature winding, 6 ... Permanent magnet piece, 6a, 42a ... Groove, 6b, 42b ... Compensation iron piece, 7 ... Rotor core,
DESCRIPTION OF SYMBOLS 42 ... Salient pole magnetic core, 100 ... Electric power steering, 101 ... Steering wheel, 102 ... Steering shaft, 103 ... Torque sensor, 104 ... Reduction gear, 105 ... Control device, 106 ... Battery, 107 ... Rack and pinion gear, 108 ... Wheel.

Claims (9)

Stator and,
Anda rotor are oppositely arranged with an air gap to the stator,
The stator is
A stator core,
A stator winding embedded in stator core provided with a,
The stator core is
It is formed by joining a plurality of divided core pieces, and includes a plurality of magnetic pole cores that form a plurality of salient poles of the stator and face the rotor,
The rotor includes a plurality of rotating magnetic poles formed by permanent magnets,
The stator is of an order lower than the number of salient pole magnetic poles, and is provided with correction means for correcting a magnetic imbalance of the stator ,
The correction means includes
A permanent magnet rotating electrical machine provided on a surface of the magnetic pole core facing the rotor, and showing a nonmagnetic portion for adjusting a magnetic flux passing through the magnetic core . Stator and,
Anda rotor are oppositely arranged with an air gap to the stator,
The stator is
A stator core,
A stator winding embedded in stator core provided with a,
The rotor is
The rotor core,
A permanent magnet to form a plurality of rotating magnetic poles, has a,
The permanent magnet is
The rotor core is composed of a plurality of permanent magnet pieces forming the plurality of rotating magnetic poles, and the plurality of permanent magnet pieces are provided on the rotor core so as to be arranged at equal intervals on the rotor core. And
The rotor includes
A correction means for correcting a magnetic imbalance of the rotor, which is of an order lower than the number of the rotating magnetic poles ,
The correction means includes
A permanent magnet rotating electrical machine provided on a surface of the permanent magnet piece facing the stator and showing a nonmagnetic part for adjusting the magnetic flux of the permanent magnet piece . Stator and,
Anda rotor are oppositely arranged with an air gap to the stator,
The stator is
A stator core,
A stator winding embedded in stator core provided with a,
The stator core is
Formed by joining a plurality of divided core pieces,
A plurality of magnetic pole cores forming a plurality of salient poles of the stator and facing the rotor;
The rotor is
The rotor core,
A permanent magnet to form a plurality of rotating magnetic poles, has a,
The permanent magnet is
The rotor core is composed of a plurality of permanent magnet pieces forming the plurality of rotating magnetic poles, and the plurality of permanent magnet pieces are provided on the rotor core so as to be arranged at equal intervals on the rotor core. And
In the stator and the rotor,
A correction means for correcting a magnetic imbalance of the stator and the rotor, which is of an order lower than the number of the salient pole magnetic poles and the rotary magnetic poles ,
The correction means includes
Provided on the surface of the magnetic pole core facing the rotor and provided on the surface of the permanent magnet piece facing the stator, or a non-magnetic part for adjusting the magnetic flux passing through the magnetic core. A permanent magnet rotating electrical machine showing at least one of the non-magnetic parts for adjusting the magnetic flux of the permanent magnet piece . The correction means includes
Wherein A which has been formed on the opposing surfaces of the rotor magnetic pole iron core, wherein show a notch formed by cutting a portion of the magnetic pole cores, the permanent magnet rotating electric machine according to claim 1 or 3 wherein. The correction means includes
4. The permanent magnet rotating electrical machine according to claim 2 , wherein the permanent magnet rotating machine is formed on a surface of the permanent magnet piece facing the stator, and shows a cutout portion formed by cutting out a part of the permanent magnet piece. The correction means includes
Are those provided on the basis of the result of the cogging torque which the stator is measured by the assembled state, the indicating those to generate cogging torque in the reverse phase to the measured cogging torque claim 1 or 3. The permanent magnet rotating electric machine according to 3 . Wherein the correction means,
Are those provided on the basis of the rotor the assembled of measured cogging torque in a state that said indicating what generates the cogging torque in the reverse phase to the measured cogging torque, claim 2 or 3. The permanent magnet rotating electric machine according to 3 . A motor generating a driving force for driving the vehicle mechanism as a power source of the vehicle-mounted power supply,
And a control unit for controlling the electric motor, and
The electric motor is a permanent magnet rotating electrical machine according to any one claims 1 to 7,
The control device is an electrical system for an on- vehicle electric actuator device , which is an inverter device that converts DC power obtained from an on-vehicle power source into AC power and supplies the AC power to the motor. An electric motor for generating an auxiliary steering force to the steering device as a power source of vehicle power supply,
And a control unit for controlling the electric motor, and
The electric motor is a permanent magnet rotating electric machine according to any one of claims 1 to 7 ,
The control device is an electric system for an electric power steering device , which is an inverter device that converts DC power obtained from a vehicle-mounted power source into AC power and supplies the AC power to the motor.

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