JP2008043127A - Controller of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller of a motor, in which a mechanism for reducing driving force for changing a phase difference between two rotors and changing the phase difference between an actuator generating driving force and the rotor can be miniaturized. <P>SOLUTION: The motor 3 includes two rotors 10 and 11 having permanent magnets 13 and 14 and a phase difference change driving means 15 changing the phase difference between the rotors 10 and 11. The controller 50 decides a manipulated variable Ir for operating a field current component (d-shaft current) of the motor 3 so that torque operated between the rotors 10 and 11 is weakened due to magnetic force of the permanent magnets 13 and 14 of the rotors 10 and 11 when the phase difference between the rotors 10 and 11 is changed, and the field current component is controlled in accordance with Ir. The manipulated variable Ir is decided in accordance with the phase difference θd between the rotors 10 and 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for an electric motor having two rotors each generating a field by a permanent magnet and capable of changing a phase difference between the two rotors.

    In a permanent magnet type electric motor, an electric motor having a double rotor structure that includes a permanent magnet that generates a magnetic field in each of two coaxially arranged rotors has been known (see, for example, Patent Document 1). . In this type of electric motor, the two rotors can rotate relative to each other about their axis, and the phase difference between the two rotors can be changed by the relative rotation. Then, by changing the phase difference between the two rotors, it is possible to change the strength (magnitude of magnetic flux) of the combined field formed by combining the fields generated by the permanent magnets of each rotor.

In the electric motor found in Patent Document 1, the phase difference between the two rotors mechanically changes in accordance with the rotational speed of the electric motor. That is, both rotors are connected via a member that is displaced in the radial direction of the electric motor by the action of centrifugal force. One of the rotors is rotatable integrally with an output shaft that outputs the generated torque of the electric motor to the outside. And the other rotor rotates relatively with respect to one rotor which can rotate integrally with an output shaft with the displacement of the said member, and it is comprised so that the phase difference between both rotors may change. In this case, when the motor is in a stopped state, the directions of the magnetic poles (directions of the magnetic flux) of the permanent magnets provided in both rotors are the same, and the strength of the combined field of these permanent magnets is maximized. The permanent magnet of each rotor is arranged so that it may become. Then, as the rotational speed of the electric motor increases, the phase difference between the rotors changes due to the centrifugal force, and the strength of the combined field of the permanent magnets of the rotors decreases.
JP 2002-204541 A

  By the way, as described above, in an electric motor capable of changing the strength of the combined field of the permanent magnets of the two rotors, the operating field of the motor can be expanded and the energy efficiency of the motor can be improved by appropriately changing the combined field. It is possible to effectively improve.

  However, in the electric motor found in Patent Document 1, it is difficult to perform fine control because the phase difference between the rotors is merely mechanically changed according to the rotational speed of the output shaft. For this reason, it has been difficult to effectively increase the operating range of the motor and improve the energy efficiency of the motor.

  Therefore, the applicant of the present application attempts to actively control the phase difference between the rotors via the actuator. By controlling the phase difference between the rotors using the actuator in this way, the phase difference can be controlled to a desired phase difference.

  On the other hand, due to the magnetic force (attraction force or repulsive force) acting between the permanent magnet provided in one of the two rotors and the permanent magnet provided in the other rotor, one of the rotors is A torque (hereinafter sometimes referred to as a magnetic torque) is generated to rotate the one with respect to the other. This magnetic torque changes according to the phase difference between the rotors, and its maximum value may be relatively large. In particular, an electric motor mounted as a driving force generation source of a vehicle on a hybrid vehicle or an electric vehicle has a high maximum value of torque required for it, and therefore a permanent magnet that generates a relatively large magnetic force is used. For this reason, the maximum value of the magnetic torque tends to be large.

  Thus, in an electric motor in which the maximum value of the magnetic torque between the two rotors is relatively large, the maximum value of the driving force (driving torque) necessary for rotating one rotor relative to the other is It will be big. For this reason, if the actuator is used to change the phase difference between the rotors as described above, the load on the actuator becomes large, and the mechanism for changing the phase difference between the actuator and the rotor increases. There was inconvenience that it was easy.

  The present invention has been made in view of such a background. For reducing the driving force for changing the phase difference between the two rotors, and for changing the phase difference between the actuator and the rotor that generate the driving force. An object of the present invention is to provide an electric motor control device capable of reducing the size of the mechanism.

  In order to achieve this object, the motor control device of the present invention has a first rotor and a second rotor that generate a magnetic field by permanent magnets, and an output that can rotate integrally with the first rotor of the two rotors. The second rotor is provided so as to be relatively rotatable with respect to the first rotor, and the second rotor is rotated relative to the first rotor by an actuator so that the second rotor is interposed between the two rotors. An electric motor control device capable of changing the strength of a composite field formed by combining the fields of permanent magnets of each rotor by changing the phase difference, and changing the phase difference between the two rotors When the energizing current of the armature of the motor is reduced so as to weaken the magnetic torque that is generated between the rotors by the magnetic force acting between the permanent magnets of the first rotor and the second rotor. Characterized by comprising a field current control means for controlling the field current component of the (first invention).

  In the present invention, the “field current component” refers to a current component that generates a field in the same direction or substantially the same direction as the combined field of the permanent magnets of the two rotors in the energization current of the armature of the motor. means. The current component corresponds to a current component in the d-axis (field axis) direction when the motor is handled in the dq coordinate system in so-called dq vector control.

  By manipulating the field current component of the energization current of the armature of the motor, the magnetic force of the permanent magnet of each rotor is changed, and consequently, the rotational force generated between the two rotors due to the magnetic force (that is, The magnetic torque can be changed. Therefore, in the first invention, when changing the phase difference between the two rotors, the field current control means reduces the rotational force generated between the rotors by the magnetic force of the permanent magnets of the rotors. The field current component of the energization current of the armature of the motor is controlled. As a result, the torque (driving force) required to rotate the second rotor relative to the first rotor is smaller than when the field current component is not operated (when the field current component is set to 0). can do.

  As a result, it is possible to reduce the burden on the actuator that generates a driving force for rotating the second rotor relative to the first rotor. As a result, the actuator and the mechanism for changing the phase difference between the rotors can be reduced in size.

  In the first invention, the magnetic torque changes in accordance with the phase difference between the two rotors. Therefore, in the first invention, the field current control means starts the change of the phase difference between the two rotors. Until the end, it is preferable that the operation amount of the field current component is sequentially determined according to the phase difference between the two rotors, and the energization current of the armature of the motor is controlled according to the operation amount (second). invention).

  According to the second aspect of the present invention, it is possible to control the field current component of the armature of the electric motor so as to weaken the magnetic torque in a desired form. Note that examples of the operation amount of the field current component include a correction amount of a current component in the d-axis direction in the dq coordinate system. In addition, the phase difference between the two rotors for determining the manipulated variable of the field current component may be detected using an appropriate sensor, but the current applied to the armature of the motor using an appropriate model. Alternatively, it may be estimated according to the detected value or the torque command value (target value). In addition, when determining the manipulated variable of the field current component according to the phase difference between the two rotors, a predetermined arithmetic expression may be used. However, the manipulated variable of the phase difference and the field current component may be used. And the operation amount of the field current component may be determined based on the map.

  In the second invention, the field current control means responds to the phase difference between the rotors so that the magnitude of the rotational force generated between the rotors by the magnetic force of the permanent magnets of the rotors is a predetermined value or less. It is preferable to determine the manipulated variable of the field current component (third invention).

  According to the third aspect of the present invention, the magnitude of the rotational force (the magnetic torque) generated between the rotors by the magnetic force of the permanent magnets of the rotors can be controlled to a predetermined value or less, so the second rotor is used as the first rotor. On the other hand, it becomes possible to manage the maximum value of the driving force required for relative rotation. As a result, it becomes easy to design the specifications of the mechanism for changing the phase difference between the actuator and the rotors.

  In addition, the field current component generates a field in the armature of the electric motor in a direction that weakens the magnetic force of the permanent magnet of each rotor. Therefore, particularly when the permanent magnet is at a relatively high temperature, If the field current component is excessive, demagnetization of the permanent magnet may occur.

  Therefore, in the first invention, the field current control means preferably includes means for limiting the field current component according to the temperature state of the permanent magnets of the two rotors (fourth invention).

  According to the fourth aspect of the present invention, it is possible to prevent the field current component that weakens the magnetic force of the permanent magnet of each rotor from becoming excessive, and to prevent the demagnetization of the permanent magnet from occurring. .

  In this case, more specifically, in the second invention or the third invention, the field current control control means has an operation amount of the field current component determined according to a phase difference between the rotors, When the allowable value set according to the temperature state of the permanent magnets of the two rotors is exceeded, a means for limiting the manipulated variable to the allowable value or less may be provided (fifth invention).

  According to this fifth aspect, when the manipulated variable of the field current component determined according to the phase difference between the two rotors exceeds the allowable value set according to the temperature state of the permanent magnets of the two rotors Since the operation amount is limited to the allowable value or less (for example, the operation amount is limited to the allowable value), the field current component that weakens the magnetic force of the permanent magnet of each rotor is prevented from being excessive, Generation of demagnetization of the permanent magnet can be prevented.

  A first embodiment of the present invention will be described with reference to FIGS.

  First, a schematic configuration of the electric motor in the present embodiment will be described with reference to FIG. 1 and FIG. FIG. 1 is a diagram showing the main part of the internal configuration of the motor 3 in the axial direction of the motor 3, and FIG. 2 is a skeleton diagram showing a drive mechanism for changing the phase difference between the two rotors of the motor 3. is there. In FIG. 1, illustration of the drive mechanism is omitted.

  Referring to FIG. 1, electric motor 3 is a DC brushless motor having a double rotor structure, and includes an outer rotor 10 as a first rotor and an inner rotor 11 as a second rotor coaxially with output shaft 3a. Outside the outer rotor 10, there is a stator 12 fixed to a housing (not shown) of the electric motor 3, and an armature (an armature for three phases) not shown is mounted on the stator 12. .

  The outer rotor 10 is formed in an annular shape and includes a plurality of permanent magnets 13 arranged at substantially equal intervals in the circumferential direction. The permanent magnet 13 is formed in a long rectangular plate shape, and in a state where the longitudinal direction is directed to the axial direction of the outer rotor 10 and the normal direction is directed to the radial direction of the outer rotor 10, Embedded in the rotor 10.

  The inner rotor 11 is also formed in an annular shape. The inner rotor 11 is disposed coaxially with the outer rotor 10 on the inner side of the outer rotor 10 with the outer peripheral surface thereof being in sliding contact with the inner peripheral surface of the outer rotor 10. A slight clearance may be provided between the outer peripheral surface of the inner rotor 11 and the inner peripheral surface of the outer rotor 10. Further, the output shaft 3 a passes through the axial center portion of the inner rotor 11 coaxially with the inner rotor 11 and the outer rotor 10.

  Further, the inner rotor 11 includes a plurality of permanent magnets 14 arranged at substantially equal intervals in the circumferential direction. The permanent magnet 14 has the same shape as the permanent magnet 13 of the outer rotor 10 and is embedded in the inner rotor 11 in the same form as that of the outer rotor 10. The number of permanent magnets 14 in the inner rotor 11 is the same as the number of permanent magnets 13 in the outer rotor 10.

  Here, in FIG. 1, the permanent magnet 13 a shown in white among the permanent magnets 13 of the outer rotor 10 and the dotted permanent magnet 13 b are opposite to each other in the direction of the magnetic poles in the radial direction of the outer rotor 10. It has become. For example, the permanent magnet 13a has an N pole on the outer side (outer peripheral surface side of the outer rotor 10) and an S pole on the inner side (inner peripheral surface side of the outer rotor 10), and the permanent magnet 13b has an outer side. This surface is the S pole and the inner surface is the N pole. Similarly, the permanent magnets 14a shown in white among the permanent magnets 14 of the inner rotor 11 and the permanent magnets 14b marked with dots are opposite to each other in the direction of the magnetic poles in the radial direction of the inner rotor 11. . For example, the permanent magnet 14a has an N-pole surface on the outer side (the outer peripheral surface side of the inner rotor 11) and an S-pole surface on the inner side (the inner peripheral surface side of the inner rotor 11). This surface is the S pole and the inner surface is the N pole.

  In the present embodiment, in the outer rotor 10, pairs of permanent magnets 13 a and 13 a adjacent to each other and pairs of permanent magnets 13 b and 13 b adjacent to each other are alternately arranged in the circumferential direction of the outer rotor 10. It is arranged. Similarly, in the inner rotor 11, pairs of permanent magnets 14 a and 14 a adjacent to each other and pairs of permanent magnets 14 b and 14 b adjacent to each other are alternately arranged in the circumferential direction of the inner rotor 11. .

  Referring to FIG. 2, outer rotor 10 is connected to output shaft 3 a so as to be rotatable integrally with output shaft 3 a of electric motor 3. The inner rotor 11 is provided to be rotatable relative to the outer rotor 10 and the output shaft 3a. By the relative rotation of the inner rotor 11, the phase difference with the outer rotor 10 can be changed. In the present embodiment, a phase difference changing device 15 having, for example, a planetary gear mechanism 30 is provided as means for causing relative rotation of the inner rotor 11 (changing the phase difference between the rotors 10 and 11).

  The planetary gear mechanism 30 of the phase difference changing device 15 is disposed in a hollow portion inside the inner rotor 11. In this embodiment, the planetary gear mechanism 30 is of a single pinion type, and is integrated with the inner rotor 10 and a first ring gear R1 fixed to the outer rotor 10 so as to be rotatable integrally with the outer rotor 10. A second ring gear R2 fixed to the inner rotor 10 so as to be rotatable is provided coaxially with the inner rotor 10 and the outer rotor 11. Both link gears R1, R2 are arranged in the axial direction thereof. A common sun gear S is provided at the axial center of both the ring gears R1 and R2, and a sun gear shaft 33 integrally having the sun gear S is rotatably supported by a plurality of bearings 34.

  A plurality of first planetary gears 31 that mesh with the sun gear S and the first ring gear R1 are provided, and these first planetary gears 31 are rotatably held by the first carrier C1. In this case, the first carrier C1 can rotate around the axis of the sun gear S, and each first planetary gear 31 can revolve around the sun gear S by the rotation of the first carrier C1.

  Further, a plurality of second planetary gears 32 that mesh with the sun gear 33 and the second ring gear R2 are provided, and these second planetary gears 32 are rotatably held by the second carrier C2. In this case, the second carrier C2 is fixed to the stator 12 (or the housing) of the electric motor 3 and cannot rotate.

  The gear ratio between the first ring gear R1, the first planetary gear 31, and the sun gear S is the same as the gear ratio between the second ring gear R2, the second planetary gear 32, and the sun gear S.

  In the planetary gear mechanism 30 configured as described above, when the output shaft 3a of the electric motor 3 and the outer rotor 10 are rotated in a state where the first carrier C1 is held unrotatable, the rotation speed is the same as that in the same direction. The inner rotor 11 rotates together with the second ring gear R2. Therefore, the inner rotor 11 rotates integrally with the outer rotor 10. When the first carrier C1 is rotationally driven, the inner rotor 11 rotates relative to the outer rotor 10. As a result, the phase difference between the inner rotor 11 and the outer rotor 10 (hereinafter referred to as inter-rotor phase difference) changes.

  Therefore, the phase difference changing device 15 according to the present embodiment rotates the first carrier C1 of the planetary gear mechanism 30 by an actuator 25 (rotation driving force generation source) such as an electric motor or a hydraulic actuator, so that the phase difference between the rotors is achieved. To change. In this case, the actuator 25 is connected to the first carrier C1 via a drive shaft 35 provided so as to be rotatable integrally with the first carrier C1, and a rotational force ( Torque).

  Supplementally, the inner rotor 11 has its permanent magnets 14a and 14b by the magnetic force (attraction force or repulsive force) acting between the permanent magnets 14a and 14b of the inner rotor 11 and the permanent magnets 13a and 13b of the outer rotor 10. And the permanent magnets 13a and 13b of the outer rotor 10 try to balance in a state where the opposite poles face each other (the state where the permanent magnets 14a and 14b face the permanent magnets 13a and 13b, respectively). For this reason, when the inner rotor 11 is rotated relative to the outer rotor 10 from the equilibrium state, a torque is generated to return the inner rotor 11 to the equilibrium state. Thus, the torque acting on the inner rotor 11 with respect to the outer rotor 10 due to the magnetic force acting between the permanent magnets 14a, 14b of the inner rotor 11 and the permanent magnets 13a, 13b of the outer rotor 10, Hereinafter referred to as magnetic torque. When the inner rotor 11 is rotated with respect to the outer rotor 10 by the phase difference changing device 15, it is necessary to apply a torque against the magnetic torque to the inner rotor 11 via the planetary gear mechanism 30. The magnetic torque changes according to the phase difference between the rotors as shown by a solid broken line graph in FIG.

  The above is the mechanical configuration of the electric motor 3 and the phase difference changing device 15 for the electric motor 3 in the present embodiment.

  In this embodiment, the single pinion type planetary gear mechanism 30 is used. However, for example, a double pinion type planetary gear mechanism may be used. In the present embodiment, the output shaft 3a of the electric motor 3 and the outer rotor 10 are configured to rotate integrally. However, the output shaft 3a of the electric motor 3 and the inner rotor 11 are configured to rotate integrally. The outer rotor 10 may be configured to rotate relative to the output shaft 3 a and the inner rotor 11. Further, the configuration of the phase difference changing device 15 is not limited to the configuration described above. For example, a hydraulic chamber may be formed inside the inner rotor 11 by a vane rotor or the like, and the inner rotor 11 may be rotated relative to the outer rotor 10 by operating the pressure in the hydraulic chamber.

  By rotating the inner rotor 11 with respect to the outer rotor 10 and changing the phase difference between the rotors by the phase difference changing device 15, the field generated by the permanent magnets 14 a and 14 b of the inner rotor 11 and the outer rotor 10 are changed. The strength (the magnetic field strength of the composite field) of the composite field with the field generated by the permanent magnets 13a and 13b (the radial field toward the stator 12) changes. Hereinafter, a state where the strength of the combined field is maximum is referred to as a field maximum state, and a state where the strength of the combined field is minimum is referred to as a field minimum state. FIG. 3A is a diagram illustrating a phase relationship between the inner rotor 11 and the outer rotor 10 in the maximum field state, and FIG. 3B is a diagram illustrating the relationship between the inner rotor 11 and the outer rotor 10 in the field minimum state. It is a figure which shows a phase relationship.

  As shown in FIG. 3A, the field maximum state is a state in which the permanent magnets 14a and 14b of the inner rotor 11 and the permanent magnets 13a and 13b of the outer rotor 10 are opposite to each other. More specifically, in this field maximum state, the permanent magnet 14a of the inner rotor 11 faces the permanent magnet 13a of the outer rotor 10, and the permanent magnet 14b of the inner rotor 11 faces the permanent magnet 13b of the outer rotor 10. In this state, in the radial direction, the directions of the magnetic fluxes Q1 of the permanent magnets 14a and 14b of the inner rotor 11 and the directions of the magnetic fluxes Q2 of the permanent magnets 13a and 13b of the outer rotor 10 are the same. The strength of the combined magnetic flux Q3 of the magnetic fluxes Q1 and Q2 (the strength of the combined field) is maximized. In a state in which the operation of the electric motor 3 is stopped, the inner rotor 11 can rotate freely (a state in which no rotational force is applied from the actuator 25 to the first carrier C1 of the planetary gear mechanism 30). The phase difference is balanced by the phase difference in the field maximum state.

  Further, as shown in FIG. 3B, the minimum field state is a state in which the permanent magnets 14a and 14b of the inner rotor 11 and the permanent magnets 13a and 13b of the outer rotor 10 face each other. More specifically, in this field minimum state, the permanent magnet 14a of the inner rotor 11 faces the permanent magnet 13b of the outer rotor 10, and the permanent magnet 14b of the inner rotor 11 faces the permanent magnet 13a of the outer rotor 10. In this state, the direction of the magnetic flux Q1 of the permanent magnets 14a and 14b of the inner rotor 11 and the direction of the magnetic flux Q2 of the permanent magnets 13b and 13a of the outer rotor 10 are opposite in the radial direction. The strength of the combined magnetic flux Q3 of these magnetic fluxes Q1 and Q2 (the strength of the combined field) is minimized.

  In this embodiment, the inter-rotor phase difference in the maximum field state is defined as 0 [deg], and the inter-rotor phase difference in the minimum field state is defined as 180 [deg].

  FIG. 4 is a graph comparing induced voltages induced in the armature of the stator 12 when the output shaft 3a of the motor 3 is operated at a predetermined rotational speed in the maximum field state and the minimum field state. It is. The vertical axis and the horizontal axis of this graph are the induced voltage [V] and the rotation angle [degree] of the output shaft 3a in electrical angle, respectively. The graph with the reference symbol a is a graph in the maximum field state (the phase difference between the rotors = 0 [deg]), and the graph with the reference symbol b is the minimum field state (the phase difference between the rotors). = 180 [deg] state). As can be seen from FIG. 5, the level of the induced voltage (amplitude level) can be changed by changing the inter-rotor phase difference between 0 [deg] and 180 [deg]. Note that when the inter-rotor phase difference is increased from 0 [deg] to 180 [deg], the strength of the combined field decreases, and the level of the induced voltage decreases accordingly.

  Thus, the induced voltage constant of the electric motor 3 can be changed by changing the phase difference between the rotors to increase or decrease the strength of the composite field. The induced voltage constant is a proportional constant that defines the relationship between the angular velocity of the output shaft 3a of the electric motor 3 and the induced voltage generated in the armature according to the angular velocity. The value of the induced voltage constant decreases as the rotor phase difference is increased from 0 [deg] to 180 [deg].

  Supplementally, for example, the rotor phase difference (minimum field phase difference) in the field minimum state is 0 [deg], and the rotor phase difference (maximum field phase difference) in the field maximum state is 180 [deg]. Of course, it may be defined as More generally speaking, the zero point of the phase difference between the rotors may be set arbitrarily.

  Next, the control device 50 for the electric motor 3 in the present embodiment will be described with reference to FIGS. FIG. 5 is a block diagram showing a functional configuration of the control device 50 (hereinafter simply referred to as the control device 50) of the electric motor 3, and FIG. 6 is a graph showing the relationship between the rotor phase difference θd of the electric motor 3 and the induced voltage constant Ke. FIGS. 7A and 7B are graphs for explaining the processing of the Ir calculating unit 57 provided in the control device 50, FIG. 8 is a flowchart showing the processing of the Ir calculating unit 57, and FIGS. (B) is a figure for demonstrating the effect | action by the process of Ir calculation part 57. FIG. In FIG. 5, the electric motor 3 is schematically illustrated, and the planetary gear mechanism 30 is expressed as a “phase variable mechanism”.

  Referring to FIG. 5, the control device 50 of the present embodiment controls energization of the electric motor 3 by so-called dq vector control. That is, the control device 50 converts the motor 3 into an equivalent circuit in a dq coordinate system, which is a two-phase DC rotating coordinate system in which the field direction is the d axis and the direction orthogonal to the d axis is the q axis. Handle. The equivalent circuit has an armature on the d-axis (hereinafter referred to as d-axis armature) and an armature on the q-axis (hereinafter referred to as q-axis armature). The dq coordinate system is a coordinate system fixed with respect to the output shaft 3 a of the electric motor 3. And the control apparatus 50 controls the energization current of the armature (the armature for 3 phases) of the electric motor 3 so that the torque according to the torque command value Tr_c given from the outside is output from the output shaft 3a of the electric motor 3. . In parallel with the energization control, the control device 50 determines the command value Ke_c of the induced voltage constant of the electric motor 3 according to the torque command value Tr_c and matches the actual induced voltage constant with the command value Ke_c. Thus, the phase difference between the rotors is controlled via the phase difference changing device 15.

  In order to perform these controls, in the present embodiment, as sensors, current sensors 41 and 42 (for detecting currents in two phases of the three phases of the armature of the motor 3, for example, the U phase and the W phase) Current detection means), a position sensor 43 (rotation position detection sensor) for detecting the rotation position θm (rotation angle) (= rotation angle of the outer rotor 10) of the output shaft 3a of the motor 3, and a phase difference between the rotors. A phase difference detector 44 is provided. The position sensor 43 is composed of, for example, a resolver. The phase difference detector 44 detects the inter-rotor phase difference based on, for example, the rotational position (target value or detected value) of the first carrier C1 by the actuator 25 of the phase difference changing device 15. If a hydraulic device is used as the phase difference changing device, the phase difference between the rotors may be detected based on the hydraulic pressure in the hydraulic chamber.

  Supplementally, the magnet temperature sensor 45 in FIG. 5 is a sensor according to a second embodiment to be described later, and is not necessary in this embodiment.

  The control device 50 is an electronic unit including a CPU, a memory, and the like, and its control processing is sequentially executed at a predetermined arithmetic processing cycle. The functional means of the control device 50 will be specifically described below.

  The control device 50 has as its main functional means an energization control unit 51 that controls the energization current of the armature of each phase of the motor 3 and a rotation speed calculation unit 52 that calculates the rotation speed Nm of the output shaft 3 a of the motor 3. A Ke calculation unit 53 for obtaining an estimated value of the actual induced voltage constant Ke of the electric motor 3, and a Ke command calculation unit 54 for determining a command value Ke_c of the induced voltage constant Ke (hereinafter referred to as an induced voltage constant command value Ke_c). With.

  Further, the control device 50 calculates a deviation ΔKe (= Ke_c−Ke) between the induced voltage constant command value Ke_c obtained by the Ke command calculating unit 54 and the Ke calculating unit 53 and the estimated value of the actual induced voltage constant Ke. The calculating unit 55 to be obtained, the phase control unit 56 for determining a control command for controlling the phase difference between the rotors and outputting it to the phase difference changing device 15, and the magnetic torque is weakened when the phase difference between the rotors is changed. And an Ir calculating unit 57 for obtaining an operation amount Ir of the energization current of the armature of the motor 3 for the purpose.

  A detected value of the rotational position θm (rotational position of the outer rotor 10) of the output shaft 3a of the electric motor 3 detected by the position sensor 43 is sequentially input to the rotational speed calculation unit 52. Then, the rotational speed calculation unit 52 calculates the rotational speed Nm of the output shaft 3a of the electric motor 3 (= the rotational speed of the outer rotor 10) by differentiating the input detection value of the rotational position θm.

  A detected value of the inter-rotor phase difference θd is sequentially input from the phase difference detector 44 to the Ke calculating unit 53. Then, the Ke calculating unit 53 obtains an estimated value of the induced voltage constant Ke from the input detected value of the inter-rotor phase difference θd based on, for example, a predetermined map. FIG. 6 is a graph showing the map. In the present embodiment, as described above, as the inter-rotor phase difference increases from 0 [deg] to 180 [deg], the strength of the combined field of the permanent magnets 13 and 14 of both rotors 10 and 11 monotonously. Get smaller. Therefore, the induced voltage constant of the electric motor 3 monotonously decreases as the phase difference between the rotors increases. For this reason, the map of FIG. 6 is set so that the estimated value of the induced voltage constant Ke monotonously decreases as the inter-rotor phase difference increases.

  The Ke command calculation unit 54 obtains the torque command value Tr_c (command value of the output torque generated on the output shaft 3 a of the electric motor 3), the power supply voltage Vdc (target value) of the electric motor 3, and the Ke calculation unit 53. The rotation speed Nm is sequentially input. The torque command value Tr_c and the power supply voltage Vdc are determined outside the control device 50 of the present embodiment. When the electric motor 3 is mounted on a vehicle (electric vehicle or hybrid vehicle) as a driving power source, for example, the torque command value Tr_c is the accelerator operation amount (depressing amount of the accelerator pedal) or the traveling speed of the vehicle. It is set according to. In this embodiment, the torque command value Tr_c includes a power running torque command value and a regenerative torque command value. The torque command value Tr_c for power running torque is a positive value, and the torque command value Tr_c for regenerative torque is a negative value. Further, the power supply voltage Vdc (target value) is set according to the detected value of the output voltage of a capacitor (not shown) as the power supply of the motor 3.

  Then, the Ke command calculation unit 54 sequentially determines the induced voltage constant command value Ke_c according to a predetermined map from the input values Tr_c, Nm, and Vdc.

  In this case, the map shows, for example, the generated voltage of the d-axis armature and the generated voltage of the q-axis armature for the set of the torque command value Tr_c, the rotation speed Nm (detected value), and the power supply voltage Vdc. The induced voltage constant command value Ke_c is determined so that the energy efficiency (ratio of output energy to input energy) of the motor 3 can be increased as much as possible while the magnitude of the combined voltage (vector sum) of the motor 3 does not exceed the power supply voltage Vdc. Is set to be.

  Here, in general, the smaller the induced voltage constant Ke (in other words, the larger the phase difference between the rotors), the more the output shaft 3a of the motor 3 can be rotated in a higher speed range. The region where the energy efficiency of the electric motor 3 is high can be shifted to the high speed rotation side. Further, the output torque of the electric motor 3 can be increased as the induced voltage constant Ke is increased (in other words, the phase difference between the rotors is decreased). Therefore, the induced voltage constant command value Ke_c may be set in consideration of the characteristics of the motor 3 with respect to the induced voltage constant Ke as described above and the operation mode required of the motor 3, and there are various ways of setting. Is possible.

  In the present embodiment, when the rotation speed Nm of the output shaft 3a and the power supply voltage Vdc are constant in the Ke command calculation unit 54, the induced voltage constant command value Ke_c is basically the absolute value of the torque command value Tr_c. As the value of | Tr_c | increases, the value of Ke_c increases (in other words, the strength of the combined field of the permanent magnets 13 and 14 of the rotors 10 and 11 increases).

  Further, when the torque command value Tr_c and the power supply voltage Vdc are constant, the induced voltage constant command value Ke_c is basically a region where the rotational speed Nm is high, and the Ke_c increases as the rotational speed Nm increases. The value is set to be small (in other words, the strength of the composite field of the permanent magnets 13 and 14 of both rotors 10 and 11 is reduced). When the torque command value Tr_c and the rotation speed Nm are constant, the induced voltage constant command value Ke_c is basically set such that the value of Ke_c decreases as the power supply voltage Vdc decreases.

  Supplementally, when setting the induced voltage constant command value Ke_c, it may be set in consideration of a request for preventing overheating of the electric motor 3.

  The phase control unit 56 receives the deviation ΔKe (= Ke_c−Ke) calculated by the calculation unit 55 and the induced voltage constant command value Ke_c output from the Ke command calculation unit 54 sequentially. Based on these input values, the phase control unit 56 controls the phase difference changing device 15 so as to converge ΔKe to 0 (so that the actual induced voltage constant Ke matches the command value Ke_c). And the control command is output to the phase difference changing device 15. In the present embodiment, for example, a command value θd_c (hereinafter, referred to as a phase difference command value θd_c) for the phase difference between the rotors is determined as the control command. In this case, the phase difference command value θd_c is determined by correcting the feedforward value determined according to Ke_c with the feedback correction amount determined according to ΔKe. The feedforward value may be determined from Ke_c by using the map of FIG. The feedback correction amount may be determined from ΔKe by a feedback control law such as a proportional law or PID law.

  The phase difference changing device 15 controls the inter-rotor phase difference θd via the actuator 25 in accordance with the phase difference command value θd_c input from the phase control unit 56.

  Supplementally, in the present embodiment, the inter-rotor phase difference command value θd_c is used as a control command for the phase difference changing device 15, but it may be a command value for the operation amount of the actuator 25 of the phase difference changing device 15, for example. The control command may be any command that can define the operation of the actuator 25 of the phase difference changing device 15.

  Further, the phase difference changing device 15 is configured such that when the phase difference command value θd_c and the inter-rotor phase difference θd detected by the phase difference detector 44 coincide with each other (when the difference between the two is a minute amount equal to or less than a predetermined value). ), The first carrier C1 of the planetary gear mechanism 30 is held unrotatable by a lock mechanism (not shown) so that the outer rotor 10 and the inner rotor 11 of the electric motor 3 rotate integrally. Therefore, in this state, the driving force of the actuator 25 is unnecessary. When the phase difference changing device is configured by a hydraulic device, an oil passage leading to a hydraulic chamber that generates a driving force for rotating the inner rotor 11 relative to the outer rotor 10 is blocked by a valve, By prohibiting the inflow / outflow of hydraulic oil, it is possible to lock the outer rotor 10 and the inner rotor 11 so that they can rotate together.

  The Ir calculation unit 57 is sequentially inputted with the inter-rotor phase difference θd detected by the phase difference detector 44 and the phase difference command value θd_c determined by the phase control unit 56. The Ir calculation unit 57 determines whether or not there is a request for changing the inter-rotor phase difference θd based on these input values, as will be described in detail later. When there is a change request, the Ir calculation unit 57 sets the operation amount Ir of the energization current of the armature of the motor 3 (specifically, the energization current of the d-axis armature) to the detected value of the inter-rotor phase difference θd. Decide accordingly. The manipulated variable Ir reduces the magnetic torque when the inter-rotor phase difference θd is changed (to reduce the torque required to rotate the inner rotor 11 relative to the outer rotor 10). It has a meaning as an operation amount for manipulating the field current component in the energization current of the armature. Hereinafter, the operation amount Ir is referred to as a driving force reducing field operation current Ir.

  The energization control unit 51 controls the energization currents of the armatures of the respective phases of the electric motor 3 so that the output torque of the electric motor 3 (generated torque of the output shaft 3a) follows the torque command value Tr_c.

  In order to perform this control, the energization control unit 51 removes unnecessary components from the output signals of the current sensors 41 and 42 to thereby detect the respective current detection values Iu, U-phase and W-phase of the armature of the motor 3. Based on the band-pass filter 61 for obtaining Iw, the detected current values Iu and Iw, and the rotational position θm (rotational angle) of the output shaft 3a detected by the position sensor 43, a d-axis electric machine is obtained by three-phase-dq conversion. A three-phase-dq converter 62 that calculates a detection value Id_s of a child current (hereinafter referred to as a d-axis current) and a detection value Iq_s of a current of a q-axis armature (hereinafter referred to as a q-axis current).

  The energization control unit 51 also includes a current command calculation unit 63 that determines a d-axis current command value Id_c that is a command value for the d-axis current and a q-axis current command value Iq_c that is a command value for the q-axis current, A calculation unit 64 that corrects Id_c by adding the driving force reduction field operation current Ir determined by the Ir calculation unit 57 to the d-axis current command value Id_c determined by the command calculation unit 63, and d after the correction A field control unit 65 for obtaining a correction value Idvol for correcting the shaft current command value Id_c1 (= Id_c + Ir), and a value obtained by adding the correction value Idvol to the d-axis current command value Idc_1 (a value obtained by correcting Id_c with Ir and Idvol) ) And the detected value Id_s of the d-axis current obtained by the three-phase-dq converter 62 .DELTA.Id (= Id_c + Ir + Idvol-Id_s) and the q axis determined by the current command calculator 63. Current command value Iq_c and the three-phase -dq And a calculation unit 67 for obtaining a deviation ΔIq between the detection value Iq_s of obtained in section 62 q-axis current (= Iq_c-Iq_s).

Here, the field controller 65 operates the d-axis current so that the magnitude of the phase voltage (induced voltage) of the armature of the motor 3 matches the power supply voltage Vdc (target value). For this reason, the field control unit 65 includes the power supply voltage Vdc (target value) of the motor 3 and the voltage command values of the d-axis armature and the q-axis armature determined by the current feedback control unit 68 described later. The shaft voltage command value Vd_c and the q-axis voltage command value Vq_c are input. The values of Vd_c and Vq_c that are input are the previous values (values obtained in the previous calculation processing cycle of the control device 50). The field control unit 65 traces the target voltage circle obtained from the power supply voltage Vdc so that the phase voltage obtained from the inputted d-axis voltage command value Vd_c and q-axis voltage command value Vq_c (in other words, The correction value Idvol for operating the d-axis current Id is determined so that the combined vector of Vd_c and Vq_c matches Vd_c as the radius of the target voltage circle. In this case, the correction value Idvol is determined by a feedback control law such as a PI control law from a deviation between the power supply voltage Vdc and the magnitude of the combined vector (= √ (Vd_c ² + Vq_c ² )).

  Further, the energization control unit 51 uses the feedback control law such as the PI control law to make the deviations ΔId and Iq close to 0 in accordance with the deviations ΔId and ΔIq calculated as described above. A current feedback control unit 68 that determines Vd_c and the q-axis voltage command value Vq_c is provided. When the d-axis voltage command value Vd_c and the q-axis voltage command value Vq_c are determined, the d-axis voltage command value and the q-axis voltage command value respectively obtained from the deviations ΔId and Iq by a Fordback control law such as a PI control law. In addition, it is preferable to obtain the d-axis voltage command value Vd_c and the q-axis voltage command value Vq_c by adding a non-interference component for canceling the influence of the speed electromotive force that interferes between the d-axis and the q-axis. .

  Further, the control device 50 converts a vector having the d-axis voltage command value Vd_c and the q-axis voltage command value Vq_c as components into a component having a magnitude V1 and a component having an angle θ1, A PWM calculation unit 70 that converts the component of the magnitude V1 and the angle θ1 into a three-phase AC voltage and energizes the armature of each phase of the electric motor 3 by PWM control via an inverter circuit (not shown). . Although not shown in FIG. 5, the PWM calculation unit 70 detects the position sensor 43 in order to convert the above V1 and θ1 into the AC voltage of the armature of each phase of the motor 3. The rotational position θm of the output shaft 3a is input.

  By the function as described above of the energization control unit 51, basically, the output torque of the motor 3 is made to follow the torque command value Tr_c (so that ΔId and ΔIq converge to 0), The energization current of the armature is controlled. At this time, the d-axis current is adjusted so that the phase voltage of the armature of the motor 3 matches the power supply voltage Vdc (target value).

  Moreover, the induced voltage constant Ke of the electric motor 3 is changed to the induced voltage constant by functions other than the energization control unit 51 of the control device 50 (functions of the Ke calculation unit 53, the Ke command calculation unit 54, the calculation unit 55, and the phase difference control unit 56). The inter-rotor phase difference θd is controlled via the phase difference changing device 15 so that the command value Ke_c is obtained (the actual combined field strength of the permanent magnets 13 and 14 is the strength corresponding to Ke_c). Is done.

  Supplementally, the energization control unit 51 and the Ir calculation unit 57 constitute field current control means in the present invention.

  Next, the process of the Ir calculation unit 57, which has been described later, will be described in detail with reference to FIGS.

  A graph indicated by a broken line in FIG. 7A shows the relationship between the rotor phase difference θd and the magnetic torque when the field current component (d-axis current) of the energization current of the armature of the motor 3 is zero. Is a graph schematically showing. Hereinafter, the magnetic torque when the field current component (d-axis current) of the energization current of the armature of the electric motor 3 is 0 may be referred to as non-reduced magnetic torque. As shown by the broken line graph, the non-relieving magnetic torque is 0 [deg] (the field maximum state) and 180 [deg] (the field minimum state) with respect to the phase difference θd between the rotors. It has a convex (mountain) characteristic that has a relatively large peak value (maximum value) at an intermediate rotor phase difference θdx. That is, as the inter-rotor phase difference θd increases from 0 [deg] to θdx, the non-relieving magnetic torque increases. When the inter-rotor phase difference θd exceeds θdx, the non-reducing magnetic torque decreases as θd increases. To do. Note that the magnetic force acting between the permanent magnet 13 of the outer rotor 10 and the permanent magnet 14 of the inner rotor 11 depends on whether the phase difference θd between the rotors is 0 [deg] or 180 [deg]. Since the direction substantially coincides with the radial direction of the electric motor 3 (the circumferential component of the magnetic force becomes substantially zero), the non-relieving magnetic torque becomes zero.

  In the state where the field current component (d-axis current) of the energization current of the armature is 0, the rotor phase difference θd is avoided while avoiding a sudden change in the rotor phase difference θd or excessive overshoot. In order to change the phase difference θd from a certain value to another value, a torque slightly larger than or substantially equal to the magnitude of the non-relieving magnetic torque is applied to the inner rotor 11 in the opposite direction to the non-reducing magnetic torque. There is a need. Therefore, particularly when the phase difference θd between the rotors is changed in the vicinity of θdx where the magnitude of the non-relieving magnetic torque peaks, the magnitude of the torque to be applied from the actuator 25 of the phase difference changing device 15 to the inner rotor 11. Becomes large, and the burden on the actuator 25 becomes large.

  On the other hand, by manipulating the field current component of the energization current of the armature of the motor 3, that is, the d-axis current, the permanent magnet 13 of the outer rotor 10 is generated by the field generated by the armature by the d-axis current. And the magnetic force acting between the inner rotor 11 and the permanent magnet 14 of the inner rotor 11 can be weakened. For example, as shown by the solid line graph in FIG. 7A, the magnetic torque can be made smaller than the non-reduced magnetic torque at any rotor phase difference θd. As a result, it is possible to reduce the torque required to rotationally drive the inner rotor 11 relative to the outer rotor 10 when the inter-rotor phase difference θd is changed (hereinafter referred to as phase difference change required torque). Hereinafter, the magnetic torque when the magnetic force acting between the permanent magnets 13 and 14 is weakened by the operation of the d-axis current as described above is referred to as reduced magnetic torque.

  The Ir calculation unit 57 weakens the magnetic torque as described above, and as a result, uses the driving force reducing field operation current Ir as the operation amount of the d-axis current for reducing the magnitude of the phase difference change necessary torque. calculate.

  The Ir calculating unit 57 determines the driving force reducing field operation current Ir by the processing shown in the flowchart of FIG.

  First, in STEP1, the Ir calculation unit 57 determines whether or not there is a request for changing the inter-rotor phase difference θd. Specifically, the Ir calculating unit 57 has a predetermined absolute value of the difference between the phase difference command value θd_c input from the phase control unit 56 and the inter-rotor phase difference θd detected by the phase difference detector 44. When the value is exceeded, it is determined that there is a request for changing the inter-rotor phase difference θd. When the absolute value of the difference between the induced voltage constant command value Ke_c determined by the Ke command calculation unit 54 and the induced voltage constant Ke (estimated value) calculated by the Ke calculation unit 53 exceeds a predetermined value. In addition, it may be determined that there is a request for changing the inter-rotor phase difference θd.

  If the determination result in STEP 1 is negative, the Ir calculation unit 57 sets the driving force reduction field operation current Ir to 0 (STEP 5). And this Ir is output to the calculating part 64 of the said electricity supply control part 51 (STEP4). Accordingly, in this case, the d-axis current is not substantially operated by the driving force reducing field operation current Ir. In this state, since the phase difference command value θd_c and the inter-rotor phase difference θd detected by the phase difference detector 44 substantially coincide with each other, as described above, the inner rotor 11 is moved by the lock mechanism (not shown). It is locked so that it can rotate integrally with the outer rotor 10.

On the other hand, if the determination result in STEP 1 is affirmative, the Ir calculation unit 57 acquires the current detected value of the inter-rotor phase difference θd from the phase difference detector 44 (STEP 2).
Next, the Ir calculation unit 57 determines the driving force reduction field operation current Ir from the acquired detected value of θd based on a predetermined map (STEP 3). The solid line graph in FIG. 7B is a graph showing the relationship between θd and Ir in the map. As shown in the figure, in this map, Ir changes with a waveform (convex waveform having a peak value) similar to the non-reduced magnetic torque with respect to θd in the range of 0 [deg] to 180 [deg]. Is set to In this case, the map shown by the solid line graph in FIG. 7B shows the magnetic force generated by the magnetic field generated when the armature is energized with the driving force reducing field operating current Ir defined thereby as the field current component. The peak value (maximum value) of torque (reduced magnetic torque) is set to be equal to or less than a predetermined value Trx (<maximum value of non-reduced magnetic torque) as shown by the solid line graph in FIG. As the value of Ir increases, the field strength (magnetic flux) of the armature by the driving force reducing field operation current Ir increases in the direction of weakening the magnetic force acting between the permanent magnets 13 and 14.

  Next, the Ir calculation unit 57 outputs the driving force reduction field operation current Ir determined according to the detected value of the inter-rotor phase difference θd as described above to the calculation unit 64 of the energization control unit 51 (STEP 4). Therefore, in this case, the substantial d-axis current (field current component) is manipulated by the driving force reducing field manipulation current Ir.

  The above is the details of the processing of the Ir calculation unit 57 in the present embodiment.

  According to the present embodiment described above, when the induced voltage constant command value Ke_c changes and a request to change the inter-rotor phase difference θd is generated, the driving force reducing field operation current Ir is obtained by the Ir calculating unit 57 as described above. The d-axis current command value Iq_c is corrected by the determined Ir. That is, the driving force reducing field operation current Ir that functions as a d-axis current (field current component) that weakens the magnetic force acting between the permanent magnets 13 and 14 is added to the d-axis current command value Iq_c. As a result, the magnetic force acting between the permanent magnets 13 and 14 can be weakened, and the maximum value of the magnetic torque (reduced magnetic torque) can be reduced to a predetermined value Trx or less. As a result, the torque required to change the phase difference can be reduced.

  This will be described with reference to FIGS. 9 (a) and 9 (b). 9A and 9B schematically show the positional relationship between the permanent magnets 13 and 14 when the inter-rotor phase difference θd is an intermediate value between 0 [deg] and 180 [deg]. ing. 9A and 9B, the pair of permanent magnets 13a and 13a adjacent to each other in FIG. 1 and the pair of permanent magnets 13b and 13b are respectively represented by one permanent magnet 13a and 13b. Yes. The same applies to the permanent magnets 14a and 14b on the inner rotor 11 side.

  Here, it is assumed that the inner rotor 10 is to be rotated with respect to the outer rotor 11 in the directions of the white arrows Ya and Yb in FIGS. In this case, when Ir = 0, since the magnetic force (attraction force and repulsive force) acting between the permanent magnets 13 and 14 is relatively large, as shown by the size of the arrow Ya in FIG. The phase difference change necessary torque for rotationally driving the inner rotor 10 (which is a torque substantially equal to the non-reduced magnetic torque) is relatively large. On the other hand, when Ir is determined as described above and added to the d-axis current command value Id_c, a magnetic flux due to Ir is generated as shown by an arrow φ in FIG. 9B. And the magnetic force which acts between the permanent magnet 13 of the outer rotor 10 and the permanent magnet 14 of the inner rotor 11 is weakened by this magnetic flux φ. That is, the reduced magnetic torque is weaker than the non-reduced magnetic torque. As a result, as shown by the size of the arrow Yb in FIG. 9B, the phase difference change required torque is lower than the phase difference change required torque indicated by the arrow Ya in FIG. 9A. As a result, the burden on the actuator 25 of the phase difference changing device 15 can be reduced. And since the phase difference change required torque can be reduced in this way, the size of the phase difference changing device 15 including the actuator 25 can be reduced.

  Further, in the present embodiment, since the driving force reducing field operation current Ir is determined based on the map of FIG. 7B, the magnetic torque (reduced magnetic torque) at an arbitrary rotor phase difference θd is shown in FIG. As shown by the solid line in FIG. 7 (a), it is less than the predetermined value Trx and smaller than the non-relieving magnetic flux torque. As a result, the phase difference change required torque can be made smaller than the non-reduced magnetic flux torque at any rotor phase difference θd.

  Note that the reduced magnetic torque can be made substantially zero at any rotor phase difference θd. In this case, as indicated by a two-dot chain line in FIG. 7B, the driving force reducing field current Ir may be set with respect to the inter-rotor phase difference θd.

  Next, a second embodiment of the present invention will be described with reference to FIG. 5, FIG. 10, and FIG. FIG. 10 is a graph for explaining the processing of the Ir calculation unit 57 in this embodiment, and FIG. 11 is a flowchart showing the processing of the Ir calculation unit 57. Note that this embodiment is different from the first embodiment only in part of the configuration and processing, so the description will focus on the differences, and the description of the same parts as in the first embodiment will be omitted.

  With reference to FIG. 5, in this embodiment, the magnet temperature sensor 45 which detects the temperature of the permanent magnets 13 and 14 is provided. The magnet temperature sensor 45 may directly detect the temperature of the permanent magnet 13 or 14, but the portion of the electric motor 3 that has a temperature substantially equal to that of the permanent magnets 13 and 14 (for example, the stator 12 or the armature). ) May be used.

  In the present embodiment, the Ir calculator 57 includes a temperature Tm (hereinafter referred to as a magnet temperature Tm) detected by the magnet temperature sensor 45 in addition to the detected value of the rotor phase difference θd and the command value θd_c. It is designed to be entered. In the present embodiment, the control process of the control device 50 is different from the first embodiment only in the process of the Ir calculator 57. Other mechanical configurations and control processes are the same as those in the first embodiment.

  Here, the driving force reducing field operation current Ir is generated by generating a magnetic flux in the direction opposite to the direction of the magnetic flux of the combined field of the permanent magnets 13 and 14 from the armature of the motor 3, thereby It has a function to weaken the magnetic force that acts between the two.

  On the other hand, particularly in a state where the temperature of the permanent magnets 13 and 14 is relatively high due to heat generation during operation of the electric motor 3, the field strength generated by the driving force reducing field operation current Ir is excessive. Then, demagnetization of the permanent magnets 13 and 14 is likely to occur. This will be described with reference to FIG. FIG. 10 shows graphs g1, g2, and g3 illustrating the relationship between the magnetic field H at different magnet temperatures Tm and the magnetic flux density B by the permanent magnets 13 or 14. In FIG. 10, the same direction as the direction of the magnetic flux density B of the permanent magnet 13 or 14 is the positive direction of the magnetic field H, and the reverse direction is the negative direction of the magnetic field H.

  As shown in the figure, when the magnetic field H is increased in the negative direction, the magnetic flux density B by the permanent magnets 13 or 14 basically decreases monotonously. However, when the magnet temperature Tm is relatively high (graphs g1 and g2 in FIG. 10), if the magnetic field H is increased in a negative direction beyond a certain value (the value of H at the points P1 and P2 in FIG. 10), it becomes permanent. Demagnetization of the magnet 13 or 14 occurs, and the magnetic flux density B rapidly decreases. The value of the magnetic field H at which the demagnetization of the permanent magnets 13 and 14 occurs approaches 0 as the magnet temperature Tm increases.

  Therefore, if the driving force reducing field operation current Ir becomes excessive in a state where the magnet temperature Tm is relatively high, demagnetization of the permanent magnets 13 and 14 may occur.

  Therefore, in this embodiment, in order to prevent the occurrence of this demagnetization, the driving force reducing field operation current Ir is limited according to the magnet temperature Tm.

  In this case, the processing of the Ir calculation unit 57 in the present embodiment is executed as shown in the flowchart of FIG. In the following, the Ir calculating unit 57 first performs the same determination in STEP 11 as in STEP 1 of FIG. 8 (determination as to whether or not there is a request to change the inter-rotor phase difference θd). If the determination result is negative, the Ir calculation unit 57 sets the driving force reduction field operation current Ir to 0 (STEP 19), and further outputs this Ir to the calculation unit 64 of the energization control unit 51. (STEP 18). Accordingly, in this case, the d-axis current is not substantially operated by the driving force reducing field operation current Ir.

  On the other hand, if the determination result in STEP 11 is affirmative, the Ir calculation unit 57 sequentially executes the same processing as STEP 2 and 3 in FIG. That is, the driving force reduction field operation current Ir is obtained from the current detected value of the inter-rotor phase difference θd based on the map shown by the solid line graph (or the two-dot chain line graph) in FIG.

  Next, the Ir calculating unit 57 acquires the detected value of the magnet temperature Tm from the magnet temperature sensor 45 (STEP 14). Further, the Ir calculation unit 57 determines the maximum driving force reduction field operation current Ir that can prevent the demagnetization of the permanent magnets 13 and 14 from the detected value of the magnet temperature Tm based on a predetermined map. The allowable maximum field current Irmax, which is a value, is obtained (STEP 15). If the current value exceeding this allowable maximum field current Irmax is set as the driving force reducing field operation current Ir, the magnetic field H generated by the armature of the motor 3 due to the Ir becomes excessive, and the permanent magnet 13, This means that 14 demagnetization may occur. In this case, as described above, the value of the magnetic field H at which the demagnetization of the permanent magnets 13 and 14 occurs approaches 0 as the magnet temperature Tm increases. Further, as the driving force reducing field operation current Ir increases, the magnetic field H generated thereby increases in the negative direction. For this reason, the map for determining the maximum allowable field current Irmax is set so that Irmax approaches 0 as the magnet temperature Tm increases (Irmax increases as the magnet temperature Tm decreases). ing. In this case, for example, the values of the driving force reducing field operation current Ir for generating the magnetic field H at the points P1 and P2 in FIG. 10 are Ir1 and Ir2 (Ir1> Ir2), respectively, and the graph g2 where the points P1 and P2 exist respectively. When the magnet temperature Tm corresponding to g3 is Tm1 and Tm2, the allowable maximum field current Irmax when the detected value of the magnet temperature Tm is Tm1 is the same as or slightly smaller than Ir1. Determined by value. Further, the allowable maximum field current Irmax when the detected value of the magnet temperature Tm is Tm2 is determined to be the same as or slightly smaller than Ir2.

  After obtaining the allowable maximum field current Irmax as described above, the Ir calculating unit 57 determines whether or not the driving force reducing field operation current Ir obtained in STEP 13 is equal to or less than the allowable maximum field current Irmax. Judgment is made (STEP 16). If the determination result is affirmative, the Ir calculation unit 57 uses the driving force reduction field operation current Ir obtained in STEP 13 as a final determination value, and the Ir is used as it is, the calculation unit 64 of the energization control unit 51. (STEP 18). If the determination result in STEP 16 is negative, the Ir calculation unit 57 limits the driving force reducing field operation current Ir to the allowable maximum field current Irmax or less in STEP 17. For example, the value of Ir is reset to Irmax. Then, the Ir calculation unit 57 sets the limited driving force reduction field operation current Ir as a final determination value, and outputs the Ir to the calculation unit 64 of the energization control unit 51 (STEP 18). The energization control unit 51 performs a substantial d-axis current operation with Ir determined as described above.

  The above is the details of the processing of the Ir calculation unit 57 in the present embodiment. According to the present embodiment, when there is a possibility that demagnetization of the permanent magnets 13 and 14 may occur, the driving force reduction field operation current Ir is limited. The load on the actuator 25 of the phase difference changing device 15 can be reduced while preventing demagnetization of the magnets 13 and 14.

  In each of the embodiments described above, a map for determining the driving force reducing field operation current Ir according to the detected value of the inter-rotor phase difference θd is set as shown in FIG. However, at an arbitrary inter-rotor phase difference θd, it is smaller than the non-reduced magnetic torque and is equal to or less than a predetermined value Trx. The setting mode of Ir according to the inter-rotor phase difference θd is not limited to this.

  For example, as shown by the solid line graph in FIG. 12A, the reduced magnetic force torque is not reduced only within the range [θd1, θd2] of the inter-rotor phase difference θd where the nonreduced magnetic torque is equal to or greater than a predetermined value Trx. The d-axis current may be manipulated (Ir is determined) so as to be smaller than the torque. In this case, as shown by the solid line graph in FIG. 12B, the driving force reducing field operation current Ir may be set according to the inter-rotor phase difference θd. That is, Ir is set in a convex waveform similar to the non-reduced magnetic torque within the range [θd1, θd2] of the rotor phase difference θd where the non-reduced magnetic torque is equal to or greater than the predetermined value Trx, and the range [θd1, [theta] d2] Ir is set to 0 at the phase difference θd between the rotors. By setting Ir in this manner, the reduced magnetic torque at an arbitrary inter-rotor phase difference θd can be made equal to or less than the predetermined value Trx in the form shown by the solid line graph in FIG.

  Further, depending on the arrangement of the permanent magnets 13 and 14, the waveform of the non-relieving magnetic torque with respect to the inter-rotor phase difference θd becomes a waveform having a plurality of peaks as shown by the broken line graph in FIG. Sometimes. In such a case, the reduced magnetic torque is larger than the non-reduced magnetic torque in the vicinity of the inter-rotor phase difference θd corresponding to each peak portion of the non-reduced magnetic torque as shown by the broken line graph in FIG. The d-axis current may be manipulated (Ir is determined) so that the reduced magnetic force torque is smoothly changed with respect to the inter-rotor phase difference θd. In this case, as shown by the solid line graph in FIG. 13B, the driving force reducing field operation current Ir may be set according to the inter-rotor phase difference θd. That is, in the vicinity of the rotor phase difference θd corresponding to each peak portion of the non-relieving magnetic torque, Ir is set in the same form as the difference between each peak portion of the non-reducing magnetic torque and the target reduced magnetic torque. . For other rotor phase differences θd, Ir is set to zero. By setting Ir in this manner, the peak value (maximum value) of the reduced magnetic torque is set to a predetermined value Trx smaller than the maximum value of the non-reduced magnetic torque in the form shown by the solid line graph in FIG. In addition, the reduced magnetic force torque (and thus the phase difference change necessary torque) can be changed more smoothly than the non-reduced magnetic torque.

  Further, in each of the embodiments, the example in which the permanent magnets 13 and 14 of the rotors 10 and 11 are arranged in the form as shown in FIG. 1 is shown, but the form of the arrangement is not limited to this. Absent. For example, as illustrated in FIGS. 14A and 14B, the permanent magnet 13 of the outer rotor 10 and the permanent magnet 14 of the inner rotor 11 may be arranged. In this example, the arrangement form of the permanent magnets 14 of the inner rotor 11 is the same as that of FIG. 1, but the permanent magnets 13 of the outer rotor 10 have the normal direction directed to the circumferential direction of the outer rotor 10. Embedded in the outer rotor 10. The permanent magnets 13 and 13 adjacent to each other of the outer rotor 10 face each other with the same polarity.

  In this case, in a state where the d-axis current (field current component) is zero, as shown in FIG. 14A, the magnetic field lines Ms between the permanent magnet 13 of the outer rotor 10 and the permanent magnet 14 of the inner rotor 11 are obtained. And a relatively large magnetic force is generated between the permanent magnets 13 and 14. Therefore, when the inner rotor 11 is to be rotated relative to the outer rotor 10 in the direction indicated by the white arrow Yc in FIG. 14A, the phase difference needs to be changed as indicated by the size of the arrow Yc. Torque is relatively large. On the other hand, by adding the driving force reducing field current component Ir as the operation amount of the d-axis current as described in the above embodiments, a magnetic flux φ by Ir is generated as shown in FIG. The magnetic force lines Ms of the ten permanent magnets 13 can be concentrated between the armature of the stator 12 and the magnetic lines of force between the permanent magnet 13 and the permanent magnet 14 of the inner rotor 11 can be reduced. As a result, the magnetic force acting between the permanent magnets 13 and 14 can be made smaller than in the case of FIG. As a result, as shown by the size of the white arrow Yd in FIG. 14B, the required torque for changing the phase difference can be made smaller than in the case of FIG. 14B.

  In the second embodiment, the magnet temperature Tm is detected by the temperature sensor 45. However, the magnet temperature Tm is estimated by an appropriate model based on the detected value of the energization current of the armature. Also good.

  In each of the above embodiments, the inter-rotor phase difference θd is detected by the phase difference detector 44. However, the armature energization current detection values (Id_s, Iq_s), the torque command value Tr_c, or the current command value It is also possible to estimate the inter-rotor phase difference θd by using an appropriate model from (Iq_c, Id_c), the rotational speed Nm, and the like.

The figure which shows the principal part of the internal structure of the electric motor in each embodiment of this invention in the axial center direction of this electric motor. The skeleton figure which shows the drive mechanism for changing the phase difference between the two rotors of the electric motor of FIG. FIG. 3A is a diagram showing a phase relationship between the two rotors of the motor of FIG. 1 in the maximum field state, and FIG. 3B is a phase diagram of the two rotors of the motor of FIG. 1 in the minimum field state. The figure which shows a relationship. The graph which shows the induced voltage of the armature of the motor of FIG. 1 in a field maximum state and a field minimum state. The block diagram which shows the functional structure of the control apparatus of the electric motor in each embodiment. 2 is a graph showing the relationship between the rotor phase difference θd and the induced voltage constant Ke of the motor of FIG. 1. FIGS. 7A and 7B are graphs for explaining the processing of the Ir calculation unit 57 in the first embodiment. The flowchart which shows the process of the Ir calculation part 57 in 1st Embodiment. The figure for demonstrating the effect | action by the process of the Ir calculation part 57 in 1st Embodiment. The graph for demonstrating the process of the Ir calculation part 57 with which the control apparatus of 2nd Embodiment of this invention was equipped. The flowchart which shows the process of the Ir calculation part 57 in 2nd Embodiment. FIGS. 12A and 12B are graphs for explaining processing of another example of the Ir calculation unit 57. FIG. FIGS. 13A and 13B are graphs for explaining still another example of the Ir calculating unit 57. FIG. 14A and 14B are views for explaining another example of the arrangement of permanent magnets of the electric motor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... Electric motor, 3a ... Output shaft, 10 ... Outer rotor (1st rotor), 11 ... Inner rotor (2nd rotor), 13, 14 ... Permanent magnet, 15 ... Phase difference changing apparatus, 25 ... Actuator, 50 ... Control Device: 51... Energization control unit (field current control means), 57... Ir calculation unit (field current control means).

Claims (5)

A first rotor and a second rotor, each generating a field by a permanent magnet, and an output shaft rotatable integrally with the first rotor of the two rotors are coaxially provided, and the second rotor is the first rotor. The second rotor is rotated relative to the first rotor by an actuator, and the phase difference between the two rotors is changed by changing the phase difference between the two rotors. A control device for an electric motor capable of changing the strength of a synthetic field formed by synthesis,
When the phase difference between the two rotors is changed, the magnetic torque, which is the torque generated between the two rotors by the magnetic force acting between the permanent magnets of the first rotor and the second rotor, is weakened. A motor control apparatus comprising field current control means for controlling a field current component of an energization current of an armature of the motor.   The field current control means sequentially determines the operation amount of the field current component according to the phase difference between the rotors from the start to the end of the phase difference change between the rotors, and the operation amount The motor control device according to claim 1, wherein an energization current of an armature of the motor is controlled in accordance with the motor.   The field current control means determines the manipulated variable of the field current component according to the phase difference between the rotors so that the magnitude of the magnetic torque generated between the rotors is not more than a predetermined value. The motor control device according to claim 2, wherein the motor control device is an electric motor.   2. The motor control apparatus according to claim 1, wherein the field current control means includes means for limiting the field current component in accordance with a temperature state of the permanent magnets of the two rotors.   The field current control control means is configured such that an operation amount of the field current component determined according to a phase difference between the two rotors exceeds an allowable value set according to a temperature state of the permanent magnets of the two rotors. 4. The electric motor control device according to claim 2, further comprising means for limiting the operation amount to the allowable value or less when the operation is performed.

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