JP4800154B2 - Electric motor control device - Google Patents

Description

The present invention relates to a motor control device that performs field control of a permanent magnet field type rotary motor by changing a phase difference between two rotors arranged around a rotary shaft .

  Conventionally, a first rotor and a second rotor are provided concentrically around the rotating shaft of a permanent magnet field type rotary electric motor, and the phase difference between the first rotor and the second rotor is changed according to the rotational speed. Thus, there is known an electric motor in which the field weakening control is performed by changing the induced voltage constant of the electric motor (see, for example, Patent Document 1).

  In such a conventional electric motor, the first rotor and the second rotor are connected via a member that is displaced along the radial direction by the action of centrifugal force. In addition, when the electric motor is stopped, the direction of the magnetic pole of the permanent magnet arranged on the first rotor is the same as that of the permanent magnetic pole arranged on the second rotor, so that the field magnetic flux is maximized (the electric motor As the rotational speed of the motor increases, the phase difference between the first rotor and the second rotor increases due to the centrifugal force, and the magnetic flux of the field decreases (the induced voltage constant of the motor decreases). It is configured as follows.

  Here, FIG. 26 shows an area in which the field weakening of the motor is necessary, with the vertical axis representing the output torque Tr and the horizontal axis representing the rotational speed N, and in the figure, u represents the motor orthogonal line (field weakening). When the motor is operated without control, the phase voltage of the motor becomes equal to the power supply voltage by the combination of the rotation speed and the output torque). In the figure, X is a region that does not require field weakening, and Y is a region that requires field weakening.

  As shown in FIG. 26, since the region Y in which field weakening is required is determined by the rotational speed N of the motor and the output torque Tr, in the conventional field weakening control based only on the rotational speed, the induced voltage constant of the motor However, there is a disadvantage that the change is excessively large or small with respect to the required field weakening control amount.

In addition, since the induced voltage constant cannot be changed regardless of the rotation speed of the motor, an appropriate induced voltage constant is suitable for operating conditions other than the rotation speed such as the output torque of the motor and the limit of the current that can be supplied. Cannot be set, and there is a disadvantage that the efficiency when operating the electric motor is deteriorated.
JP 2002-204541 A

  The present invention has been made in view of the above background, and it is possible to appropriately set the induced voltage constant of an electric motor having a double rotor according to the operating state of the electric motor, and to increase the efficiency when operating the electric motor. An object of the present invention is to provide an electric motor control device that can perform the above-described operation.

The present invention has been made in order to achieve the above object, a first rotor and a second rotor having a plurality of field by the permanent magnets, and placed around the rotary shaft has a permanent magnet field type rotating electric machine And a rotor phase difference changing means for changing a rotor phase difference that is a phase difference between the first rotor and the second rotor, and a DC voltage supplied from a DC power source. An inverter that converts the voltage into a multiphase AC voltage and applies it to the armature of the motor, and a phase current that is a vector sum of currents that flow through the armature of each phase of the motor via the inverter according to a predetermined torque command The present invention relates to an improvement in an electric motor control device including an energization control means for controlling the motor.

  Then, when obtaining the torque according to the torque command based on the rotational speed detection means for detecting the rotational speed of the electric motor, the output voltage of the DC power supply, the rotational speed of the electric motor, and the torque command. Rotor phase difference control means for changing the rotor phase difference by the rotor phase difference changing means so as to maximize the efficiency of the electric motor is provided (corresponding to claim 1).

  According to the present invention, the rotor phase difference control means causes the rotor phase difference to be maximized so that the efficiency of the motor is maximized when obtaining the torque according to the torque command according to the operating state of the motor. Be changed. Therefore, the range in which the efficiency of the electric motor can be maximized can be expanded within the range of the energization ability of the phase current by the energization control means.

  Further, the rotor phase difference control means is a preset induced voltage constant that minimizes the loss of the motor with respect to the DC voltage supplied to the inverter, the rotational speed of the motor, and the torque of the motor. Applying the output voltage of the DC power supply, the rotational speed of the motor detected by the rotational speed detection means, and the torque command to the correlation map for determining the corresponding induced voltage constant, The rotor phase difference of the electric motor is changed according to an induced voltage constant (corresponding to claim 2).

  According to the present invention, the rotor phase difference control means can acquire the optimal induced voltage constant that minimizes the loss of the electric motor according to the operating condition of the electric motor by using the correlation map. By changing the rotor phase difference of the electric motor according to the induced voltage constant, the rotor phase difference at which the efficiency of the electric motor becomes maximum can be set according to the operating condition of the electric motor.

  Further, the electric motor is handled by converting it into an equivalent circuit having a d-axis armature on the d-axis that is the magnetic flux direction of the field and a q-axis armature on the q-axis orthogonal to the d-axis. The control means reduces the difference between the actual value of the d-axis current that is the current flowing through the d-axis armature and the command value, and the actual value and command value of the q-axis current that is the current flowing through the q-axis armature. The energization control is performed so as to reduce the difference between the motors, and the torque according to the torque command is determined based on the induced voltage constant of the motor according to the rotor phase difference and the angular velocity according to the rotation speed of the motor. Of the obtained combinations of the d-axis current and the q-axis current, the combination that minimizes the loss of the motor is determined as the first dq current setting, and the d-axis current and the q-axis current according to the first dq current setting are determined. Induced voltage generated in d-axis armature when supplied and q-axis electric machine Is induced based on the induced voltage constant of the motor according to the rotor phase difference and the rotation speed of the motor, and the induced voltage generated in the estimated d-axis armature and the q-axis armature A first dq determination voltage, which is a vector sum of the generated induced voltage, is equal to or lower than a limit voltage set according to the output voltage of the DC power supply, and a dq axis which is a vector sum of the d-axis current and the q-axis current. When the first dq determination current, which is the magnitude of the current based on the first dq current setting, is equal to or less than a predetermined limit current, the d-axis current based on the first dq current setting is used as the d-axis current command. And a current command setting means for setting the q-axis current by the first dq current setting to a command value of the q-axis current (corresponding to claim 3).

  According to this invention, the current command setting means has the maximum efficiency of the motor with respect to the torque command when the operating condition of the motor is not limited by the limit voltage and the limit current. A command value for d-axis current and a command value for q-axis current are set by the first dq current setting. And thereby, the efficiency at the time of operating the electric motor can be maximized.

Further, the current command setting means is configured such that when the first dq determination voltage is equal to or lower than the limit voltage and the first dq determination current is larger than the limit current, the magnitude of the dq axis current is It is determined whether it is possible to calculate a second dq current setting that is a combination of a d-axis current and a q-axis current at which the motor current becomes the limit current and the torque of the motor becomes maximum, and the second dq When the calculation of the current setting is possible, the induced voltage generated in the d-axis armature and the induced voltage generated in the q-axis armature when the d-axis current and the q-axis current are supplied by the second dq current setting are The vector sum of the induced voltage generated in the estimated d-axis armature and the induced voltage generated in the q-axis armature is estimated based on the induced voltage constant of the motor according to the rotor phase difference and the rotation speed of the motor. The second dq determination voltage is When the serial limit voltage or less, the q-axis current according to the second dq current setting and the command value of the q-axis current with the d-axis current according to the second dq current setting to a command value of the d-axis current (Corresponding to claim 4).

  According to the present invention, the current command setting means is configured such that when the operating condition of the electric motor is not restricted by the limit voltage, but is restricted by the limit current, the magnitude of the dq current is A command value for the d-axis current and a command value for the q-axis current are set by the second dq current setting that maximizes the output torque of the motor within the range of the limit current. In this case, the efficiency of the electric motor is not maximized, but the controllable range of the electric motor can be expanded within the range of the limited current.

  Further, the current command setting means has a d-axis in which when the second determination voltage becomes higher than the limit voltage, the magnitude of the dq-axis current becomes the limit current, and the dq-induced voltage becomes the limit voltage. It is determined whether or not the third dq current setting that is a combination of the current and the q-axis current can be calculated. When the third dq current setting can be calculated, the third dq current setting is determined. The d-axis current based on the setting is used as a command value for the d-axis current, and the q-axis current based on the third dq current setting is used as the command value for the q-axis current (corresponding to claim 5).

  According to the present invention, the current command setting means is configured such that the operating condition of the electric motor is restricted by the limit voltage, but the dq current magnitude is the limit current when the dq induced voltage is the limit voltage. When the following third dq current setting can be calculated, the d-axis current command value and the q-axis current command value are set by the third dq current setting. And thereby, the controllable range of the electric motor can be expanded under the restriction by the limit voltage and the limit current.

Further, the current command setting means is configured such that when the first dq determination voltage is equal to or lower than the limit voltage and the first dq determination current is larger than the limit current, the magnitude of the dq axis current is It is determined whether it is possible to calculate a second dq current setting that is a combination of a d-axis current and a q-axis current at which the motor current becomes the limit current and the torque of the motor becomes maximum, and the second dq When the calculation of the current setting is impossible, the combination of the d-axis current and the q-axis current at which the magnitude of the dq-axis current becomes the limit current and the torque of the motor is maximized is determined as the fourth dq current setting. The d-axis current set by the fourth dq current setting is used as a command value for the d-axis current, and the q-axis current set by the fourth dq current setting is used as a command value for the q-axis current. Corresponds to item 6).

  According to the present invention, the current command setting means cannot calculate the second dq current setting when the operating condition of the motor is not restricted by the limit voltage but is restricted by the limit current. Is set, the d-axis current command value and the q-axis current command value are set by the fourth dq current setting in which the magnitude of the dq-axis current becomes the limit current and the torque of the motor becomes maximum. . And thereby, the controllable range of the electric motor can be expanded under the limit current.

  Further, the current command setting means obtains a torque corresponding to the torque command when the first dq determination voltage is higher than the limit voltage, and generates an induced voltage q generated in the d-axis armature. It is determined whether or not it is possible to calculate the fifth dq current setting, which is a combination of the d-axis current and the q-axis current, in which the dq induced voltage, which is a vector sum of the induced voltage generated in the shaft armature, becomes the limit voltage. When the fifth dq current setting can be calculated and the second dq determination current, which is the magnitude of the dq axis current by the fifth dq current setting, is equal to or less than the limit current, The d-axis current set by the fifth dq current setting is used as a d-axis current command value, and the q-axis current set by the fifth dq current setting is used as a q-axis current command value. Corresponding).

  According to the present invention, the current command setting means can obtain a torque according to the torque command when the operating condition of the motor is restricted by the limit voltage and the dq induced voltage is the limit voltage. It is determined whether or not the fifth dq current setting can be calculated. When the fifth dq current setting can be calculated and the second determination current, which is the magnitude of the dq axis current by the fifth dq current setting, is equal to or less than the limit current, The d-axis current based on the fifth dq current setting is used as the d-axis current command value, and the q-axis current based on the fifth dq current setting is used as the q-axis current command value. In this case, torque according to the torque command can be ensured.

  Further, the current command setting means can calculate the fifth dq current setting, and when the second dq determination current is larger than the limit current, the magnitude of the dq axis current is It is determined whether it is possible to calculate a third dq current setting that is a combination of a d-axis current and a q-axis current that is a limiting current and the dq induced voltage is the limiting voltage, and the third dq When the current setting can be calculated, the d-axis current based on the third dq current setting is used as the d-axis current command value, and the q-axis current based on the third dq current setting is used as the q-axis current command value. (Corresponding to claim 8).

  According to the present invention, the current command setting means can calculate the fifth dq current setting, but when the second determination current is larger than the limit current, It is determined whether it is possible to calculate a third dq current setting that is a combination of a d-axis current and a q-axis current whose magnitude is the limit current and whose dq induced voltage is the limit voltage. When the third dq current setting can be calculated, the d-axis current based on the third dq current setting is used as a command value for the d-axis current and the q-axis current based on the third dq current setting. Is the command value of the q-axis current. As a result, the controllable range of the electric motor can be expanded within a range that is restricted by the limit voltage and the limit current.

  Further, the current command setting means obtains a torque corresponding to the torque command when the first dq determination voltage is higher than the limit voltage, and generates an induced voltage q generated in the d-axis armature. It is determined whether or not it is possible to calculate the fifth dq current setting, which is a combination of the d-axis current and the q-axis current, in which the dq induced voltage, which is a vector sum of the induced voltage generated in the shaft armature, becomes the limit voltage. When the calculation of the fifth dq current setting is impossible, the dq induced voltage becomes the limit voltage, and the torque of the motor with respect to the induced voltage constant of the motor according to the rotor phase difference. The sixth dq current setting that is a combination of the d-axis current and the q-axis current that maximizes the dq-axis current is calculated, and the third dq determination current that is the magnitude of the dq-axis current based on the sixth dq current setting is When the current is less than The d-axis current based on the dq current setting of 6 is used as the command value for the d-axis current, and the q-axis current based on the sixth dq current setting is used as the command value for the q-axis current. ).

  According to the present invention, when the operating condition of the motor is restricted by the limit voltage and the calculation of the fifth dq current setting is impossible, the dq induced voltage becomes the limit voltage, and the rotor The sixth dq current setting that maximizes the torque of the motor is calculated with respect to the induced voltage constant of the motor according to the phase difference, and the d-axis current by the sixth dq current setting is calculated as the d-axis current. The q-axis current based on the sixth dq current setting is used as the command value for the q-axis current. In this case, the torque of the electric motor can be maximized under the restriction by the restriction voltage, and the controllable range of the electric motor can be expanded.

  Further, the current command setting means cannot calculate the fifth current setting, and when the third dq determination current is larger than the limit current, the magnitude of the dq axis current is the limit. It is determined whether it is possible to calculate a third dq current setting that is a combination of a d-axis current and a q-axis current, which is a current and the dq induced voltage is the limit voltage, and the third dq current is determined. When the setting can be calculated, the d-axis current set by the third dq current setting is used as the d-axis current command value, and the q-axis current set by the third dq current setting is set as the q-axis current command value. (Corresponding to claim 10).

  According to the present invention, the current command setting means is configured such that the operating condition of the electric motor is restricted by the limit voltage, but the dq current magnitude is the limit current when the dq induced voltage is the limit voltage. When the following third dq current setting can be calculated, the d-axis current command value and the q-axis current command value are set by the third dq current setting. And thereby, the controllable range of the electric motor can be expanded under the restriction by the limit voltage and the limit current.

  Embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a control block diagram of an electric motor control apparatus according to the present invention, FIG. 2 is a block diagram of an electric motor including the double rotor shown in FIG. 1, and FIGS. 3 and 4 are for changing a phase difference between an outer rotor and an inner rotor. FIG. 5 is a flowchart showing the overall operation of the motor control device, and FIGS. 6 to 8 are explanatory diagrams of the expansion effect of the controllable range of the motor by changing the rotor phase difference. FIGS. 9 to 11 are explanatory diagrams of a procedure for creating a map for determining the optimum induced voltage constant for performing the maximum efficiency control, and FIG. 12 is a process for calculating the optimum induced voltage constant for performing the maximum efficiency control. FIG. 13 is an explanatory diagram of a map for converting an induced voltage constant into a rotor phase difference, FIGS. 14 to 22 are explanatory diagrams of a method for determining an optimum current command value, and FIGS. Controllable range of motor It is a flowchart of a process for setting a current command value for performing expansion of.

  Referring to FIG. 1, a motor control device (hereinafter referred to as a motor control device) of the present invention controls the operation of a motor 1 which is a DC brushless motor having a double rotor. First, the configuration of the electric motor 1 will be described with reference to FIGS.

  As shown in FIG. 2, the electric motor 1 includes an inner rotor 11 in which the fields of the permanent magnets 11a and 11b are arranged at equal intervals along the circumferential direction, and the fields of the permanent magnets 12a and 12b along the circumferential direction. And a stator 10 having an armature 10a for generating a rotating magnetic field with respect to the inner rotor 11 and the outer rotor 13. One of the inner rotor 11 and the outer rotor 12 corresponds to the first rotor of the present invention, and the other corresponds to the second rotor of the present invention.

  The inner rotor 11 and the outer rotor 12 are both arranged concentrically so that the rotating shaft is coaxial with the rotating shaft 2 of the electric motor 1. And in the inner side rotor 11, the permanent magnet 11a which makes S pole the rotation axis 2 side, and the permanent magnet 11b which makes N pole the rotation axis 2 side are arrange | positioned alternately. Similarly, in the outer rotor 12, permanent magnets 12 a having the S pole as the rotating shaft 2 side and permanent magnets 12 b having the N pole as the rotating shaft 2 side are alternately arranged.

  The electric motor 1 includes a relative rotation mechanism (not shown) such as a planetary gear mechanism in order to change a rotor phase difference that is a phase difference between the outer rotor 12 and the inner rotor 11. By operating with 25 (see FIG. 1), the rotor phase difference can be changed. As the actuator 25, for example, an electric motor or hydraulic pressure can be used. Further, the relative rotation mechanism and the actuator 25 constitute the rotor phase difference changing means of the present invention.

  The phase difference between the outer rotor 12 and the inner rotor 11 can be changed to the advance side or the retard side within a range of at least 180 electrical degrees. The state of the electric motor 1 is the permanent magnet 12a of the outer rotor 12. , 12b and the permanent magnets 11a and 11b of the inner rotor 11 are arranged so that the same poles face each other, and the permanent magnets 12a and 12b of the outer rotor 12 and the permanent magnets 11a and 11b of the inner rotor 11 are different. It can be set as appropriate between the field-strengthened state in which the poles are arranged to face each other.

  FIG. 3 (a) shows a field strengthening state. Since the directions of the magnetic flux Q2 of the permanent magnets 12a and 12b of the outer rotor 12 and the magnetic flux Q1 of the permanent magnets 11a and 11b of the inner rotor 11 are the same, they are synthesized. The magnetic flux Q3 increases. On the other hand, FIG. 3B shows a field weakening state, and the directions of the magnetic flux Q2 of the permanent magnets 12a and 12b of the outer rotor 12 and the magnetic flux Q1 of the permanent magnets 11a and 11b of the inner rotor 11 are opposite. The synthesized magnetic flux Q3 becomes smaller.

  FIG. 4 is a graph comparing the induced voltages generated in the armature of the stator 10 when the motor 1 is operated at a predetermined rotational speed in the state of FIG. 3A and the state of FIG. The axis is set to the induced voltage (V), and the horizontal axis is set to the electrical angle (degrees). In the figure, a is the state of FIG. 3A (field strengthening state), and b is the state of FIG. 3B (field weakening state). From FIG. 4, it can be seen that the level of the induced voltage is significantly changed by changing the phase difference between the outer rotor 12 and the inner rotor 11.

  Thus, the induced voltage constant Ke of the electric motor 1 can be changed by changing the phase difference between the outer rotor 12 and the inner rotor 11 to increase or decrease the magnetic flux of the field. Thereby, compared with the case where the induced voltage constant Ke is constant, the operable region for the output and the rotational speed of the electric motor 1 can be expanded. Moreover, since the loss of the electric motor 1 is reduced by the dq coordinate conversion compared to the case where the field weakening control is performed by energizing the armature on the d-axis (field axis) side, the efficiency of the electric motor can be increased. .

  Next, the configuration of the motor control device will be described with reference to FIG. The motor controller treats the motor 1 by converting it into an equivalent circuit using 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, and the torque command Tr_c given from the outside is used. The energization amount for the electric motor 1 is controlled so that the corresponding torque is output from the electric motor 1.

  The motor control device is an electronic unit composed of a CPU, a memory, and the like. Based on the torque command Tr_c, the rotation speed Nm of the motor 1, and the calculated value Ke_s of the induced voltage constant of the motor 1, the d-axis side armature ( Hereinafter, a command value Id_c of a current (hereinafter referred to as a d-axis current) flowing in a d-axis armature and a current (hereinafter referred to as a q-axis current) flowing in a q-axis side armature (hereinafter referred to as a q-axis armature). The current command calculating unit 50 (corresponding to the current command setting means of the present invention) for calculating the command value Iq_c of the current and the current sensors 61 and 62 and unnecessary components are removed by the BP (band pass) filter 57 Based on the current detection signal and the rotor angle θm of the outer rotor 12 detected by the resolver 70, three-phase calculation of a d-axis current detection value Id_s and a q-axis current detection value Iq_s by three-phase / dq conversion / Dq conversion A portion 56 is provided.

  The motor control device also includes a subtractor 51 that calculates a deviation ΔId between the d-axis current command value Id_c and the detected value Id_s, and a subtractor 52 that calculates a deviation ΔIq between the q-axis current command value Iq_c and the detected value Iq_s. , ΔId and ΔIq, a command value Vd_c for a voltage applied to the d-axis armature (hereinafter referred to as d-axis voltage) and a command value Vq_c for a voltage applied to the q-axis armature (hereinafter referred to as q-axis voltage). A current FB (feedback) control unit 53 to be determined, an rθ conversion unit 54 that converts Vd_c and Vq_c into an angle θ and a magnitude r, and a three-phase AC voltage corresponding to θ and r from the DC voltage Vdc to generate an electric motor 1 PWM output unit 55 (including the function of the inverter of the present invention).

  The subtractor 51, the subtractor 52, the current FB control unit 53, the rθ conversion unit 54, the BP filter 57, and the three-phase / dq conversion unit 56 constitute an energization control unit of the present invention.

  Further, the motor control device differentiates the rotor angle θm of the electric motor 1 detected by the resolver 70 and outputs the rotational speed Nm of the electric motor 1 (corresponding to the rotational speed detecting means of the present invention), torque command The rotor position by the Ke command value calculation unit 90 and the phase difference detector 26 for calculating the command value Ke_c of the optimum induced voltage constant based on the value Tr_c, the output voltage Vdc of the DC power supply (not shown) and the rotational speed Nm of the motor. A Ke calculating unit 92 that calculates an induced voltage constant Ke_s corresponding to the detected value θd_s of the phase difference, a subtractor 91 that calculates a difference ΔKe between Ke_c and Ke_s, and a command value θd_c of the rotor phase difference from the Ke_s and ΔKe to calculate the actuator 25 is provided. The Ke command calculation unit 90, the subtractor 91, the Ke calculation unit 92, the phase difference control unit 80, and the phase difference detector 26 constitute the rotor phase difference control means of the present invention.

  Next, in accordance with the flowchart shown in FIG. 5, the optimum induced voltage constant by the Ke command calculation unit 90 for executing “maximum efficiency control” for controlling the operation of the motor 1 so that the efficiency of the motor 1 is maximized. The calculation process of the command value Ke_c and the calculation process of the d-axis command value Id_c and the q-axis current command value Iq_c by the current command calculation unit 50 will be described.

  Steps 1 to 3 in FIG. 5 are processes performed by the Ke command calculation unit 90, and the Ke calculation unit 90 acquires the output voltage Vdc of the DC power supply, the torque command Tr_c, and the rotation speed Nm of the electric motor 1 in STEP1. Then, in STEP 2, a correlation map for determining an induced voltage constant optimal for executing “maximum efficiency control” for Vdc, Tr_c, Nm stored in advance in a memory (not shown) is acquired in STEP 1. Ke obtained by applying (Vdc, Tr_c, Nm) is determined as a command value Ke_c of the induced voltage constant.

  Here, FIG. 6 shows that the dq induced voltage Vo, which is the vector sum of the induced voltage generated in the d-axis armature of the motor 1 and the induced voltage generated in the q-axis armature, is limited voltage Vom (dq that can be output from the PWM calculation unit 55). Efficiency, total loss, and iron loss when the output torque of the motor 1 is constant in a region below the base rotational speed that is the voltage (set near the upper limit of the vector sum of the d-axis voltage and the q-axis voltage). , Copper loss, and change in dq-axis current, which is a vector sum of d-axis current and q-axis current, the left vertical axis represents loss, the right vertical axis represents efficiency, and the horizontal axis represents d-axis current. The phase between the q-axis currents (current phase) β is set.

In the figure, a represents the efficiency, b represents the total loss, c represents the iron loss, d represents the copper loss, and e represents the change in the magnitude of the dq-axis current. In FIG. 6, P ₁₀ is constant torque the magnitude of the dq-axis current necessary for obtaining a is minimum (torque / dq axis magnitude of the current is maximized) is a point, P ₁₁ obtains a constant torque This is the point at which the loss at the time is minimum (efficiency is maximum).

  As shown in FIG. 6, in the region below the base rotational speed, “maximum torque / current control” that minimizes the magnitude of the dq-axis current when obtaining a constant torque, and the motor 1 when obtaining a constant torque. In “maximum efficiency control” that maximizes the efficiency of the current, the phase β between the selected d-axis current and q-axis current is different. In general, in “maximum efficiency control”, the current is consumed to advance the current and reduce the iron loss. Therefore, the magnitude of the dq-axis current required to obtain a constant torque is “maximum torque / “Maximum efficiency control” is more than “current control”. Therefore, when the electric motor 1 cannot be operated by the “maximum efficiency control” due to the limitation of the dq axis current that can be supplied, the controllable range of the electric motor 1 can be increased by operating the electric motor 1 by the “maximum torque / current control”. Can be enlarged.

  Then, the Ke command calculation unit 90 appropriately changes the induced voltage constant Ke of the motor 1 according to the torque command value Tr_c, the rotation speed Nm of the motor 1 and the output voltage Vdc of the DC power source, thereby obtaining “maximum efficiency control”. The range in which the electric motor 1 can be operated by “can be expanded.

  Here, FIG. 7 (a) shows the relationship between the torque and the rotational speed of the motor 1 when the induced voltage constant Ke is intermediate, the vertical axis is set to torque (Tr), and the horizontal axis is The rotational speed (Nm) is set. FIG. 7B shows the relationship between the torque and the rotational speed of the electric motor 1 when the induced voltage constant Ke is switched to the maximum, middle, and minimum three stages, and is the same as FIG. 7A. The vertical axis is set to torque (Tr), and the horizontal axis is set to the rotational speed (Nm).

In FIG. 7A, the range of A ₁₀ (the range surrounded by the boundary of y ₁₀ , the Tr axis, and the Nm axis) indicates the controllable range of the electric motor 1 by “maximum efficiency control”, and A ₁₀ + B ₁₀ Range (Tr = Tr ₁₀ straight line, x ₁₀ boundary, Tr axis, Nm axis surrounded range) "Maximum output control" (field weakening current is added to expand the motor operating range The controllable range by (control) is shown.

In FIG. 7B, the range of A ₁₁ (the range surrounded by the boundary line of y ₁₁ , the Tr axis, and the Nm axis) is the range of the electric motor 1 by “maximum efficiency control” when the induced voltage constant Ke is maximized. The controllable range is shown. The range of A ₁₁ + B ₁₁ (Tr = Tr ₁₁ straight line, x ₁₁ boundary line, Tr axis, N m axis surrounded range) is “maximum output control” when the induced voltage constant Ke is maximized. The controllable range by is shown.

The range of A ₁₂ (the range surrounded by the boundary line of y ₁₂ , the Tr axis, and the Nm axis) indicates the controllable range of the electric motor 1 by “maximum efficiency control” when the induced voltage constant Ke is in the middle. . Further, the range of A ₁₂ + B ₁₂ (Tr = Tr ₁₂ straight line, x ₁₂ boundary line, Tr axis, N m axis surrounded range) is “maximum output control” when the induced voltage constant Ke is in the middle. The controllable range by is shown.

The range of A ₁₃ (the range surrounded by the boundary line of y ₁₃ , the Tr axis, and the Nm axis) indicates the controllable range of the electric motor 1 by “maximum efficiency control” when the induced voltage constant Ke is minimized. . The range of A ₁₃ + B ₁₃ (Tr = Tr ₁₃ straight line, x ₁₃ boundary line, Tr axis, N m axis surrounded range) is “maximum output control” when the induced voltage constant Ke is minimized. The controllable range by is shown.

  Compared to the case where the induced voltage constant Ke shown in FIG. 7A is fixed, in FIG. 7B, by increasing the induced voltage constant Ke, as shown by the arrow Ar2 in the figure, “ The controllable range of the electric motor 1 by “maximum efficiency control” can be expanded in the direction of increasing the output torque Tr. Further, by reducing the induced voltage constant Ke, the controllable range of the electric motor 1 by the “maximum efficiency control” can be expanded in the direction of increasing the rotational speed Nm, as indicated by the arrow Ar1 in the figure.

FIG. 8A shows a constant value at P _{20 in} FIG. 7B (a point within the controllable range by the “maximum efficiency control” regardless of whether the induced voltage constant Ke is maximum, intermediate, or minimum). The change in the phase (current phase) between the d-axis current and the q-axis current when torque is obtained is shown. The left vertical axis is set to the magnitude of the dq-axis current and the loss of the motor 1, and the right side The vertical axis is set to the efficiency of the electric motor 1, and the horizontal axis is set to the current phase.

Then, in FIG. 8 (a), a ₁₁ denotes the efficiency in the case of the maximum induced voltage constant Ke, a ₁₂ denotes the efficiency in the case of the moderate induced voltage constant Ke, a ₁₃ is the induced voltage constant Ke The efficiency is shown when is minimized. P ₃₁ is a point where the efficiency is maximum at a ₁₁ , P ₃₂ is a point where the efficiency is maximum at a ₁₂ , and P ₃₃ is a point where the efficiency is maximum at a ₁₃ .

B ₁₁ represents a loss when the induced voltage constant Ke is maximized, b ₁₂ represents a loss when the induced voltage constant Ke is intermediate, and b ₁₃ represents a loss when the induced voltage constant Ke is minimized. Is shown. P ₃₄ is a point where the loss is minimized at b ₁₁ , P ₃₅ is a point where the loss is minimized at b ₁₂ , and P ₃₆ is a point where the loss is minimized at b ₁₃ .

C ₁₁ represents the magnitude of the dq-axis current when the induced voltage constant Ke is maximized, c ₁₂ represents the magnitude of the dq-axis current when the induced voltage constant Ke is intermediate, and c ₁₃ represents the induced voltage constant. The magnitude of the dq axis current when the voltage constant Ke is minimized is shown. P ₃₇ is the point where the magnitude of the dq-axis current is minimum at c ₁₁ , P ₃₈ is the point where the magnitude of the dq-axis current is minimum at c ₁₂ , and P ₃₉ is the minimum of the dq-axis current at c ₁₃ . It is a point.

From a ₁₁ ~a ₁₃ and c ₁₁ to c ₁₃ in FIG. 8 (a), dq by setting the dq-axis current according to the "maximum efficiency control" and _{(P 31, P 32, P} 33) "maximum torque / current control" The current phase is different from the setting of the shaft current (P ₃₇ , P ₃₈ , P ₃₉ ), and the magnitude of the dq axis current is smaller in “maximum torque / current control” than in “maximum efficiency control”. I understand. It can also be seen from (P ₃₁ , P ₃₂ , P ₃₃ ) that the efficiency of the electric motor 1 when obtaining a constant torque can be increased by changing the induced voltage constant Ke.

Further, FIG. 8B shows P _{21 in} FIG. 7B (the point where the induced voltage constant Ke is outside the controllable range by the “maximum efficiency control” in any case of the maximum, middle and minimum). FIG. 9 shows the change in the current phase when a constant output torque is obtained. As in FIG. 8A, the left vertical axis is set to the magnitude of the dq axis current and the loss of the motor 1, and the right side The vertical axis is set to the efficiency of the electric motor 1, and the horizontal axis is set to the current phase.

In FIG. 8B, a ₂₁ indicates the efficiency when the induced voltage constant Ke is maximized, a ₂₂ indicates the efficiency when the induced voltage constant Ke is intermediate, and a ₂₃ indicates the induced voltage constant Ke. The efficiency is shown when is minimized. Further, the point P ₄₁ is composed efficiency maximum in a _21, P ₄₂ is the point at which the efficiency is maximum at a _22, P ₄₃ is the point at which the efficiency is maximum at a _23.

B ₂₁ indicates a loss when the induced voltage constant Ke is maximized, b ₂₂ indicates a loss when the induced voltage constant Ke is intermediate, and b ₂₃ indicates a loss when the induced voltage constant Ke is minimized. Is shown. C ₂₁ represents the magnitude of the dq-axis current when the induced voltage constant Ke is maximized, c ₂₂ represents the magnitude of the dq-axis current when the induced voltage constant Ke is intermediate, and c ₂₃ represents the induced voltage constant. The magnitude of the dq axis current when the voltage constant Ke is minimized is shown. P ₄₇ is the point where the magnitude of the dq axis current is minimum at c ₂₁ , P ₄₈ is the point where the magnitude of the dq axis current is minimum at c ₂₂ , and P ₄₉ is the magnitude of the dq axis current at c ₂₃ . Is the point where is the smallest.

Also in FIG. 8 (b), the from a ₂₁ ~a ₂₃ and c ₂₁ to c _23, setting of the dq-axis current according to the "maximum efficiency control" _{(P 41, P 42, P} 43) and "maximum torque / current control" It can be seen that the current phase is different from the dq-axis current setting (P ₄₇ , P ₄₈ , P ₄₉ ). It can also be seen from (P ₄₁ , P ₄₂ , P ₄₃ ) that the efficiency of the electric motor 1 when obtaining a constant torque can be increased by changing the induced voltage constant Ke.

  Next, a procedure for creating a correlation map used in STEP 2 of FIG. 5 will be described with reference to FIGS. FIG. 9 shows the creation of an optimum Ke map that determines the optimum induced voltage constant Ke for each output voltage when the setting of the output voltage Vdc of the DC power supply is switched to three stages (Vdc = V1, V2, V3). The procedure to do is shown.

S1 and S2 in FIG. 9 are processes for creating the optimum Ke map KM1 for the output voltage Vdc = V1, and in S1, the induced voltage constants Ke (Ke = Ke1, Ke2, Ke3, Ke4, Ke4 <Ke3 < For Ke2 <Ke1), a dq current map is created by plotting the dq axis current when the torque Tr and the rotational speed Nm of the electric motor 1 are varied. Specifically, as shown in FIG. 10A, the loss of the motor 1 is plotted when the rotational speed Nm and the output torque Tr are varied under the conditions of (Vdc = V1, Ke = Ke1). , to create a loss map M _11. This plotting work is carried out by experiments and computer simulations.

Similarly, the loss map M ₁₂ under the condition of (Vdc = V1, Ke = Ke2), the loss map M ₁₃ under the condition of (Vdc = V1, Ke = Ke3), and (Vdc = V1, to create a loss map M ₁₄ under the conditions of Ke = Ke4). In S2, the four loss maps M ₁₁ , M ₁₂ , M ₁₃ , and M ₁₄ created in this way are compared, and the induction that minimizes the loss at each plot point of (torque Tr, rotation speed Nm) is performed. An optimum Ke map KM1 is generated by selecting the voltage constant Ke.

As shown in FIG. 10B, the optimum Ke map KM1 determines an induced voltage constant Ke that minimizes the loss of the electric motor 1 with respect to the torque Tr and the rotational speed Nm. For the condition of (Tr, Nm) = (Tr ₁₀ , Nm ₁₀ ), an induced voltage constant Ke = Ke1 is determined.

S3 and S4 are processes for creating an optimum Ke map for the output voltage Vdc = V2, and in the same manner as the processes of S1 and S2 described above, the conditions under S3 (Vdc = V2, Ke = Ke1) are used. Loss map M ₂₁ , loss map M ₂₂ under the condition of (Vdc = V2, Ke = Ke2), loss map M ₂₃ under the condition of (Vdc = V2, Ke = Ke3), (Vdc = V2, Ke = The loss map M ₂₄ under the condition of Ke4) is created, and the optimum Ke map KM2 under the condition of Vdc = V2 is created at S4.

S5 and S6 are processes for creating an optimum Ke map for the output voltage Vdc = V3. In the same manner as the processes of S1, S2 and S3, S4 described above, in S5 (Vdc = V3, Ke = Ke1). Loss map M ₃₁ under conditions, loss map M ₃₂ under conditions of (Vdc = V3, Ke = Ke2), loss map M ₃₃ under conditions of (Vdc = V3, Ke = Ke3), (Vdc = The loss map M ₃₄ under the condition of V3, Ke = Ke4) is created, and the optimum Ke map KM3 under the condition of Vdc = V3 is created at S6.

  As described above, the optimum Ke map KM1 for Vdc = V1, the optimum Ke map KM2 for Vdc = V2, and the optimum Ke map for Vdc = V3 as shown in FIG. A correlation map consisting of KM3 is created. FIG. 11B is a setting example of the induced voltage constant Ke in the optimum Ke maps KM1, KM2, and KM3. The vertical axis is set to the torque Tr (power running torque and regenerative torque), and the horizontal axis is set to the rotational speed Nm. Has been.

  In FIG. 11B, D1 is a range where the induced voltage constant Ke1 is selected, D2 is a range where the induced voltage constant Ke2 is selected, D3 is a range where the induced voltage constant Ke3 is selected, and D4 is an induced voltage constant. K4 is the selected range. Thus, the controllable range of the motor 1 by the “maximum efficiency control” can be expanded by decreasing the induced voltage constant as Ke 1 → Ke 2 → Ke 3 → Ke 4 as the rotational speed of the motor 1 increases.

  Not the correlation map but the dq-axis current required for each induced voltage constant Ke (Ke = Ke1, Ke2, Ke3, Ke4) under the conditions of the power supply voltage Vdc, the torque command Tr_c, and the rotation speed Nm. Of the Kes that maximize the torque of the electric motor 1 with the dq-axis current, the one that minimizes the loss of the electric motor 1 may be determined as the optimum Ke. FIG. 12 is a flowchart of processing for determining the optimum Ke by calculating the dq-axis current in this way.

In the flowchart of FIG. 12, first, in STEP 10, the output voltage Vdc of the DC power supply, the torque command Tr_c, and the rotation speed Nm are acquired. Then, the loop of STEP11 to STEP16 is executed for Ke (n) = Ke (1), Ke (2), Ke (3), Ke (4), and in STEP12, Vdc, Tr_c, Nm, K (n) are set. The corresponding current command values (Id_c (n), Iq_c (n)) are calculated in the same manner as in the case of the current command calculation unit 50 described later. Further, in the following STEP 13, the torque Tr (n) of the electric motor 1 at Ke (n), Id_c (n), Iq_c (n) is calculated by the equation (7) described later, and in Step 14, Ke (n), Id_c (n) ) And Iq_c (n), the loss W _loss (n) of the electric motor 1 is calculated by the following equations (8) to (10). In STEP 15, Tr (n) and W _loss (n) are stored in a memory (not shown).

Then, in STEP 17, the Ke (n) that minimizes the loss W _loss (n) among the Ke (n) that maximizes the torque Tr (n) of the electric motor 1 is determined as the optimum Ke. As a result, the induced voltage constant Ke that minimizes the loss of the electric motor 1 can be determined with respect to the torque command Tr_c, as in the case of searching for the optimum Ke map described above.

  Next, in STEP 3 of FIG. 5, the Ke command calculation unit 90 outputs the optimum Ke determined in STEP 2 to the phase difference control unit 80 (see FIG. 1) as the command value Ke_c of the induced voltage constant. The subsequent STEP 4 is processing by the phase difference control unit 80. The phase difference control unit 80 applies Ke_c to the Ke / θd conversion map shown in FIG. 13 and determines the corresponding θd as the rotor phase difference command value θd_c. To do. The Ke / θd map is created by experiment or computer simulation, and the data of the Ke / θd map is stored in the memory in advance.

  Then, the phase difference control unit 80 outputs the rotor phase difference command value θd_c to the actuator 25, whereby the actuator 25 sets the rotor phase difference of the electric motor 1 to θd_c, and the induced voltage constant Ke of the electric motor 1 becomes the optimum Ke. Be controlled.

  Subsequent STEP 5 is processing by the current command calculation unit 50 (see FIG. 1). The current command calculation unit 50 basically performs a command value Id_c for the d-axis current and a command value Iq_c for the q-axis current by “maximum efficiency control”. Is output to the subtracters 51 and 52 (see FIG. 1).

  First, the basic concept of the d-axis current command value I_c and the q-axis current command value Iq_c calculation processing by the current command value calculation unit 50 will be described with reference to FIGS. From the equivalent circuit on the d-axis side of the electric motor 1 shown in FIG. 14A and the equivalent circuit on the q-axis side of the electric motor 1 shown in FIG. Under the corresponding flux linkage Ψa, the current relational expressions are expressed by the following expressions (1) to (4), and the voltage equations are expressed by the following expressions (5) and (6).

  Where ω: angular velocity of the motor 1, Lq: q-axis armature inductance, Rc: q-axis armature and d-axis armature coil resistance.

  Where Ψa is the flux linkage corresponding to the optimum Ke, and Ld is the inductance of the d-axis armature.

  However, Ra: Resistance component other than the coil resistance Rc of the d-axis armature and the q-axis armature.

  Further, the torque T of the electric motor 1 can be calculated by the following equation (7).

Where P _{n is the number of} pole pairs.

  Further, the copper loss Wc of the electric motor 1 can be calculated by the following equation (8), and the iron loss Wi of the electric motor 1 can be calculated by the following equation (9). And the loss of the electric motor 1 is computable with the following formula | equation (10).

Here, when the operating state of the electric motor 1 by the angular velocity ω and the torque Tr is given, the condition for minimizing the loss W _loss (maximizing the efficiency of the electric motor 1) is expressed by the following equation (11). Is given by the following equation (12) from the above equations (7) to (10).

  When Iod satisfying the relationship of the above equation (12) is obtained, Ioq is given by the following equation (13) from the above equation (7). The d-axis current Id and the q-axis current Iq are given by the following expressions (14) and (15).

  The conditional expression in the case of a non-salient pole type motor with Ld = Lq is the following expression (16), and Iod is expressed by the following expression (17) as a function of only the angular velocity ω.

  Next, FIG. 15A shows “maximum efficiency control” when the angular velocity ω of the motor 1 is constant on the Id-Iq plane with the q-axis current Iq on the vertical axis and the d-axis current Id on the horizontal axis. A maximum efficiency curve L (L0, L1, L2, L3, L4) that is a locus of a combination (Id, Iq) (hereinafter referred to as a current vector) of the d-axis current Id and the q-axis current Iq that realizes It represents a constant torque curve T (T1, T2, T3) which is a locus of a current vector where the torque is constant.

In FIG. 15 (a), the maximum efficiency curve of L0 ω = ω ₀ = _0, the maximum efficiency curve L1 is ω = ω _1, the maximum efficiency curve L2 is ω = ω _2, L3 is a maximum of omega = omega ₃ The efficiency curve, L4, is the maximum efficiency curve with ω = ω ₄ = ∞ (ω ₀ <ω ₁ <ω ₂ <ω ₃ <ω ₄ ). Further, T1 is a constant torque curve of Tr = Tr _1, T2 is constant torque curve of Tr = Tr _2, T3 is the constant torque curve of Tr = Tr _3.

  When the angular velocity ω is 0, the iron loss is 0, so L0 matches the maximum torque / current curve where the copper loss is minimized. Further, the maximum efficiency curve L moves to the left in FIG. 15A as the angular velocity ω increases (L0 → L1 → L2 → L3 → L4). In L4 where the angular velocity ω is ∞, the copper loss against the iron loss is increased. Since the loss is negligible, L4 matches the maximum torque / flux curve that minimizes the iron loss. When a torque command Trx and an angular velocity ωx as operating conditions of the electric motor 1 are given, current vectors for realizing “maximum efficiency control” are a constant torque curve of Tr = Trx and a maximum efficiency curve of ω = ωx. It becomes an intersection.

  Next, the magnitude of the dq induced voltage Vo, which is the vector sum of the induced voltage Vod generated in the d-axis armature and the induced voltage Voq generated in the q-axis armature, is expressed by the following equation (18). The magnitude of the inter-terminal voltage Va, which is the vector sum of the inter-terminal voltage and the inter-terminal voltage of the q-axis armature, is expressed by the following equation (19).

  And it becomes possible to control the terminal voltage Va below the limit voltage Vom by equivalent field weakening control. When the induced voltage Vo is maintained at the limit voltage Vom, Vo = Vom can be substituted into the above equation (18) to obtain the following equation (20).

  The above equation (20) becomes an ellipse (constant induced voltage ellipse) on the Id-Iq plane. The diameter of the constant induced voltage ellipse decreases as the angular velocity ω increases. FIG. 15B shows a constant induced voltage ellipse N (N1, N2, N3) and a constant torque curve T (on the Id-Iq plane with the vertical axis representing the q-axis current Iq and the horizontal axis representing the d-axis current Id. T1, T2, T3) and the maximum torque / magnetic flux curve L3.

In FIG. 15 (b), N1 is omega = omega ₁ of the constant induced voltage ellipse, N2 is constant induced voltage ellipse of ω = ω _2, N3 is a constant induced voltage ellipse of _{ω = ω 3 (ω 1 <} ω 2 <Ω ₃ ). Further, T1 is a constant torque curve of Tr = Tr _1, T2 is constant torque curve of Tr = Tr _2, T3 is the constant torque curve of Tr = Tr _3. For example, if the constant value is ω = ω ₁ , the current vector under the limit voltage Vom is constant ω = ω ₁ as indicated by the arrow Ar3 in the figure as the load of the motor 1 increases. on the induced voltage ellipse N1 moves _{P 21 → P 22 → P 23} .

  If the angular velocity ω and the q-axis current Iq are given from the above equation (20), the d-axis current Id can be obtained by the following equations (22) and (23) under the condition of the following equation (21). it can.

In this way, two types of d-axis current Id can be calculated with respect to the q-axis current Iq, but the smaller the current value, the better. Therefore, the load states such as P ₂₁ and P _{22 in} FIG. Then, Id is calculated by the above equation (22), and after the load increases to Id = −Ψa / Ld, Id is calculated by the above equation (23). When the current vector reaches the intersection P ₂₃ with maximum torque / flux curve L4, the torque is maximized.

  When the current supplied to the armature of the motor 1 is limited, the motor 1 can be operated within a constant current circle (limit current circle) having a radius of the limit current Iam. At this time, selecting the current vector on the constant induced voltage ellipse and operating the electric motor 1 is an operation method for minimizing the loss of the electric motor 1.

  The selection method of the current vector command values (Id_c, Iq_c) to be set under the various conditions described above is summarized as follows.

  [Maximum Efficiency Control Region] Since the induced voltage Vo has a margin in the voltage up to the limit voltage Vom in the low speed operation region, only the limit current Iam needs to be considered. At this time, in order to maximize the efficiency of the electric motor 1, the d-axis current Id and the q-axis current may be calculated by the above formulas (14) and (15) (the above formulas (12) and (13) are calculated). Satisfy Iod, Ioq)

Here, FIG. 16A shows a maximum efficiency curve L (L ₁₀ , L ₁₁ , L ₁₂ , L ₁₃ on the Id-Iq plane where the vertical axis is q-axis current Iq and the horizontal axis is d-axis current Id. , L ₁₄ , L ₁₅ , L ₁₆ , L ₁₇ , L ₁₈ ), a constant torque curve T (T 1, T 2, T 3), and a constant induced voltage ellipse N (N ₁₀ , N ₁₁ , N ₁₂ , N ₁₃ , N ₁₄ , N ₁₅ ) and the limit current circle AM.

In FIG. 16A, L ₁₀ is a maximum efficiency curve (maximum torque / current curve) of ω = ω ₁₀ (= 0), L ₁₁ is a maximum efficiency curve of ω = ω ₁₁ , and L ₁₂ is ω = ω ₁₂ . Maximum efficiency curve, L ₁₃ is the maximum efficiency curve at ω = ω ₁₃ , L ₁₄ is the maximum efficiency curve at ω = ω ₁₄ , L ₁₅ is the maximum efficiency curve at ω = ω ₁₅ , L ₁₆ is the maximum efficiency at ω = ω ₁₆ A curve, L ₁₇ is a maximum efficiency curve of ω = ω ₁₇ , and L ₁₈ is a maximum efficiency curve (maximum torque / magnetic flux curve) of ω = ω ₁₈ (= ∞) (ω ₁₀ <ω ₁₁ <ω ₁₂ <ω ₁₃ <Ω ₁₄ <ω ₁₅ <ω ₁₆ <ω ₁₇ <ω ₁₈ ).

Further, T1 is a constant torque curve of Tr = Tr _1, T2 is constant torque curve of Tr = Tr _2, T3 is the constant torque curve of Tr = Tr _3. N ₁₁ is a constant induced voltage ellipse with ω = ω ₁₁ , N ₁₂ is a constant induced voltage ellipse with ω = ω ₁₂ , N ₁₃ is a constant induced voltage ellipse with ω = ω ₁₃ , and N ₁₄ is a constant induced voltage ellipse with ω = ω ₁₄ . The induced voltage ellipse, N ₁₅ is a constant induced voltage ellipse with ω = ω ₁₅ , N ₁₆ is a constant induced voltage ellipse with ω = ω ₁₆ , and N ₁₇ is a constant induced voltage ellipse with ω = ω ₁₇ .

The combination of the d-axis current Id and the q-axis current Iq in the “maximum efficiency control” is the maximum efficiency curve L in FIG. On the maximum efficiency curve L, when the magnitude I (= √ (Id ² + Iq ² )) of the vector sum of the d-axis current Id and the q-axis current Iq becomes the limit current Iam (I = Iam), the maximum efficiency Generated torque is maximized. The efficiency As you decrease the current phase is no longer a maximum, torque increases while approaching the maximum torque / current curve L _10. Maximum torque at the time occurrence, maximum torque / current curve L ₁₀ and limit current circle AM and the intersection P ₅₂ (Ida, IQA) becomes the current settings in, Ida and IQA the following equation (24), the equation (25) Can be calculated.

The armature flux linkage at this time is expressed by the following equation (26), and the angular velocity ω _base at which the dq induced voltage Vo (= ωψoa) reaches the limit voltage Vom is given by the following equation (27).

In FIG. 16 (a), a maximum torque / current curve L ₁₀ P ₅₂ that intersects the limitation current circle AM, because the constant induced voltage ellipse N ₁₀ is crossed, omega ₁₁ is omega _base becomes, omega ₁₁ or more angular velocity in can not be controlled current vector (Id, Iq) to P _52. In this case, the upper limit value (base speed) ω _{base of the} angular velocity at which the electric motor 1 can be operated with the maximum generated torque is the “constant torque operation region”. In this “constant torque operation region”, the magnitude I of the dq-axis current and the dq induced voltage Vo are I = Iam and Vo <Vom.

FIG. 16B shows FIG. 16A with the vertical axis set to torque (Tr) and the horizontal axis set to angular velocity (ω), and the range from ω = 0 to ω ₁₁ is “ “Constant torque operation range”.

[First equivalent field weakening region] In the velocity region where the angular velocity exceeds ω _bese , it is necessary to consider the limiting voltage Vom in addition to the limiting current Iam. At this time, it is the “maximum torque / magnetic flux control” that maximizes the torque in consideration of only the limit voltage Vom. Since “maximum torque / magnetic flux control” does not consider the limitation by the limit current Iam, the range of application is limited when the limitation by the limit current Iam is considered. That is, in the range where the maximum torque / magnetic flux curve L ₁₈ shown in FIG. 16A does not exist inside the current limit circle AM, the application of “maximum torque / magnetic flux control” is impossible.

Here, in the speed region where the operation at the point P ₅₂ (“maximum torque / current control” at Idq = Iam) and “maximum torque / flux control” cannot be performed, the generated torque is maximized because the current vector is current-limited. The control is performed at the intersection P ₅₄ (when ω = ω ₁₁ ) or P ₅₆ (when ω = ω ₁₂ ) of the circle AM and the constant voltage limiting ellipse. At this time, the d-axis current Idb and the q-axis current Iqb are It can be calculated by the following equations (28) and (29).

  This control mode corresponds to the case where the dq-axis current Idq is set to the limit current Iam in the equivalent field-weakening control, and the dq-axis current magnitude I and the dq-induced voltage Vo are always I = Iam and Vo = Vom. .

Here, FIG. 17A shows a maximum torque / current curve Q ₂₀ , a maximum torque / magnetic flux curve R ₂₀ on the Id-Iq plane where the vertical axis is q-axis current Iq and the horizontal axis is d-axis current Id. The limit current circle AM, the constant induced voltage ellipse N ₂₀ (ω = ω ₂₀ ), N ₂₁ (ω = ω ₂₁ ), and N ₂₂ (ω = ω ₂₂ ) are shown. FIG. 17B shows FIG. 17A with the vertical axis set to torque (Tr) and the horizontal axis set to angular velocity (ω).

When Ψdmin = Ψa−LdIam ≧ 0, as shown in FIG. 17A, the maximum torque / magnetic flux curve R ₂₀ exists outside the current limit circle AM, so “maximum torque / magnetic flux control” is applied. I can't. Therefore, at the angular velocity ω ₂₂ at which the constant voltage limit ellipse N ₂₂ is in contact with the current limit circle AM, the current vector (Id, Iq) reaches the point Pc (Id = −Iam, Iq = 0) and the output torque of the motor 1 is 0 (output limit). The angular velocity ω _{c that} is the output limit (ω _{22 in} FIG. 17A) can be calculated by the following equations (30) and (31).

[Second Equivalent Field-weakening Control] Next, FIG. 18A is similar to FIG. 17A, on the Id-Iq plane where the vertical axis is the q-axis current Iq and the horizontal axis is the d-axis current Id. The maximum torque / current curve Q ₃₀ , the maximum torque / magnetic flux curve R ₃₀ , the limit current circle AM, the constant induced voltage ellipse N ₃₀ (ω = ω ₃₀ ), N ₃₁ (ω = ω ₃₁ ) are shown. FIG. 18B shows FIG. 18A with the vertical axis set to torque (Tr) and the horizontal axis set to angular velocity (ω).

In the case of Ψ _dmin = Ψa−LdIam <0, as shown in FIG. 18A, the maximum torque / magnetic flux curve R ₃₀ exists inside the current limit circle AM. Can be transferred to. Here, “maximum torque / magnetic flux control” may be applied in order to obtain the maximum torque output in consideration of the limitation by the limiting voltage Vom without the limitation by the limiting current Iam. The current vector (Idc, Iqc) at this time is calculated by the function of the angular velocity ω according to the following equations (32) to (34) as the intersection of the maximum torque / magnetic flux curve R ₃₀ and the constant induced voltage ellipse N _31. Can do.

In this case, the current vector calculated (Id, Iq) = (Idc , Iqc) moves toward the point M in accordance with the maximum torque / flux curve R ₃₀ on increasing the speed of FIG. 18 (a). In this control mode, Idq and Vdq are Idq <Iam and Vo = Vom. In FIG. 18B, the range of current vectors (Id, Iq) that can be calculated with respect to FIG. 17B is expanded.

Next, FIGS. 19 to 22 show that the angular velocity ω of the electric motor 1 is ω ₁₀ (FIG. 19 (a)), ω ₁₁ (FIG. 19 (b)), ω under the condition of FIG. 16 (a) described above. ₁₂ (FIG. 20A), ω ₁₃ (FIG. 20B), ω ₁₄ (FIG. 21A), ω ₁₅ (FIG. 21B), ω ₁₆ (FIG. 22A), ω ₁₇ (FIG. 22B), the locus of the current vector (Id, Iq) that can be set to (ω ₁₀ <ω ₁₁ <ω ₁₂ <ω ₁₃ <ω ₁₄ <ω ₁₅ <ω ₁₆ <ω ₁₇ ) It is shown.

In FIG. 19 (a), the order not constrained by voltage and current, the current vector (Id, Iq) trajectories Ve1 of, omega = omega ₁₀ maximum efficiency curve (maximum torque / current curve) L ₁₀ a current limit circle to move to the intersection P ₅₂ of the AM. In this case, the torque up to the maximum Tr ₃ can be obtained by the “maximum efficiency control”.

In FIG. 19 (b), the locus Ve2 of the current vector (Id, Iq) is to the intersection P ₅₃ with maximum efficiency curve L ₁₁ and the current limit circle AM of omega = omega _11, "maximum moving on the L ₁₁ "Efficiency control" can be performed. Then, a constant induced voltage ellipse N _{11 of} ω = ω ₁₁ intersects with the current limiting circle AM and is limited by the voltage from P ₅₃ , but the maximum Tr on the current limiting circle AM until P ₅₂ where the voltage is limited. Torque up to ₃ can be obtained.

In FIG. 20 (a), the locus Ve3 of the current vector (Id, Iq) is to the intersection P ₅₅ with maximum efficiency curve ω = ω ₁₂ L ₁₂ and a current limit circle AM, "maximum by moving the L ₁₂ on "Efficiency control" can be performed. The electric motor 1 can be operated up to P ₅₂ where the constant induced voltage ellipse N _{12 of} ω = ω ₁₂ and the current limiting circle AM intersect and are restricted by the voltage from P ₅₅ , which is restricted by the current. . In this case, the torque Tr ₃ cannot be obtained.

In FIG. 20 (b), the locus Ve4 of the current vector (Id, Iq) is to the intersection P ₅₇ with maximum efficiency curve L ₁₃ and the current limit circle AM of omega = omega _13, "maximum moving on the L ₁₃ "Efficiency control" can be performed. The electric motor 1 can be operated until P ₅₆ where the constant induced voltage ellipse N _{13 of} ω = ω ₁₃ and the current limiting circle AM intersect and is restricted by the voltage, although restricted by the current from P _57. . In this case, the maximum torque that can be obtained is further reduced as compared with FIG.

In FIG. 21 (a), the locus Ve5 of the current vector (Id, Iq) is to the intersection P ₅₉ of the constant induced voltage ellipse N ₁₄ of the maximum efficiency curve L ₁₄ and omega = omega ₁₄ of ω = ω _14, L ₁₄ You can move up to perform “maximum efficiency control”. The electric motor 1 can be operated up to P ₅₈ where the constant induced voltage ellipse N ₁₄ and the current limiting circle AM intersect and are restricted by the current, although restricted by the voltage from P ₅₉ . In this case, the maximum torque that can be obtained is further reduced as compared with FIG.

In FIG. 21 (b), the locus Ve6 of the current vector (Id, Iq), because the constant induced voltage ellipse N ₁₅ maximum efficiency curve L ₁₅ and omega = omega ₁₅ of omega = omega ₁₅ are overlapped from the P _75, It is not possible to perform “maximum efficiency control” by moving over N ₁₅ due to voltage restrictions. Then, the electric motor 1 can be operated until P _{60 at} which the constant induced voltage ellipse N ₁₅ and the current limiting circle AM intersect and are restricted by the current. In this case, the maximum torque that can be obtained is further reduced as compared with FIG.

In FIG. 22 (a), the order maximum efficiency curve L ₁₆ of omega = omega ₁₆ is outside of the constant induced voltage ellipse N ₁₆ of omega = omega _16, and constrained by voltage be performed "maximum efficiency control" Can not. The locus Ve7 of the current vector (Id, Iq) moves on N ₁₆ until P ₆₁ where the constant induced voltage ellipse N ₁₆ and the current limiting circle AM intersect and is restricted by the current. In this case, the maximum torque that can be obtained is further reduced as compared with FIG.

In FIG. 22 (b), the order maximum efficiency curve L ₁₇ of omega = omega ₁₇ is outside of the constant induced voltage ellipse N ₁₇ of omega = omega _17, and constrained by voltage be performed "maximum efficiency control" Can not. The locus Ve8 of the current vector (Id, Iq) moves on N ₁₇ until P ₆₂ where the constant induced voltage ellipse N ₁₇ and the maximum torque / flux curve L ₁₈ intersect. In this case, the maximum torque that can be obtained is further reduced as compared with FIG.

  Based on the above description, FIG. 23 to FIG. 25 show the setting process of the current command values (the d-axis current command value Id_c_ and the q-axis current command value Iq_c) by the current command calculation unit 50 in STEP 5 of FIG. This will be described with reference to the flowchart.

  In STEP 20 of FIG. 23, the current command calculation unit 50 calculates the limit voltage Vom from the output voltage Vdc of the DC power source, and the angular velocity of the motor 1 from the rotational speed Nm of the motor 1 calculated by the differentiator 71 (see FIG. 1). ω is calculated, and the linkage flux Ψa when the optimum Ke is calculated by the Ke command calculation unit 90 is calculated.

  In subsequent STEP 21, the first dq current setting (Id1, Iq1) is obtained by substituting the torque command Tr_c and the interlinkage magnetic flux Ψa calculated in STEP 20 into the above formulas (7) and (12) to (15). Is calculated. In STEP 22, the dq induced voltage Vo1 (corresponding to the first dq determination voltage of the present invention) is calculated as (Id, Iq) = (Id1, Iq1) in the above formula (6).

In the next STEP23, the current command calculation unit 50 determines whether or not the dq induced voltage Vo1 is less than or equal to the limit voltage Vom. If the dq induced voltage Vo1 is less than or equal to the limit voltage Vom, the process proceeds to STEP24, where the dq induced voltage is determined. When Vo1 is higher than the limit voltage Vom, the process branches to STEP 70 in FIG. In subsequent STEP 24, whether or not the magnitude of the dq axis current (√ (Id1 ² + Iq1 ² ), corresponding to the first dq determination current of the present invention) by the first dq current setting is equal to or less than the limit current Iam. When the magnitude of the dq-axis current is equal to or less than the limit current Iam, the process proceeds to STEP25, and when the magnitude of the dq-axis current is greater than the limit current Iam, the process branches to STEP30.

  When the process proceeds to STEP 25, since the operating condition is not restricted by the limiting voltage Vom and the limiting current Iam, the “maximum efficiency control” can be executed. Therefore, in STEP 25, the current command calculation unit 50 sets the first dq current setting (Id1, Iq1) calculated in STEP 21 as the d-axis current and q-axis current command values (Id_c, Iq_c). Then, proceeding to STEP 26, the current command calculation unit 50 ends the current command value calculation processing.

  Further, when branching to STEP 30, the operating condition is not limited by the limiting current Vom but is limited by the limiting current Iam. Therefore, in STEP 30, the current command calculation unit 50 determines whether it is possible to calculate the second dq current setting that satisfies the above equation (7) and the following equation (35). The second dq current setting is a current vector at the intersection of the constant torque curve and the current limit circle.

  When the second dq current setting can be calculated, the process branches to STEP 40 in FIG. 24, and the current command calculation unit 50 calculates a current vector (Id2, Iq2) by the second dq current setting. In STEP 41, the current command calculation unit 50 calculates the dq induced voltage Vo2 (corresponding to the second dq determination voltage of the present invention) as (Id, Iq) = (Id2, Iq2) in the above formula (6). To do.

  In subsequent STEP 42, the current command calculation unit 50 determines whether the dq induced voltage Vo2 is equal to or lower than the limit voltage Vom. When the dq induced voltage Vo2 is equal to or lower than the limit voltage Vom, the process proceeds to STEP 43, and the current command calculation unit 50 sets the second dq current setting (Id2, Iq2) calculated in STEP 40 to the d-axis current and the q-axis current. The command value (Id_c, Iq_c) is used. Then, the process proceeds to STEP 26 in FIG. 23, and the current command calculation unit 50 ends the calculation process of the current command value.

  On the other hand, when the dq induced voltage Vo is higher than the limit voltage Vom in STEP42, the process branches to STEP50, and the current command calculation unit 50 can calculate the third dq current setting by the above equations (20) and (35). Judge whether there is. The calculation of the third dq current setting is possible when the condition of the following expression (36) is satisfied, and the third dq current setting is a current vector at the intersection of the current limiting circle and the constant induced voltage ellipse. It becomes.

  When the calculation of the third dq current setting is possible, the process proceeds to STEP 51, where the current command calculation unit 50 calculates the third dq current setting (Id3, Iq3), and at STEP52, the third dq current setting is calculated. The settings (Id3, Iq3) are set as command values (Id_c, Iq_c) for the d-axis current and the q-axis current. Then, the process proceeds to STEP 26 in FIG. 23, and the current command calculation unit 50 ends the current command value setting process.

  Further, when the calculation of the third dq current setting (Id3, Iq3) is impossible in STEP50, the process branches to STEP60, and the current command calculation unit 50 calculates the current command value by the following equations (37) and (38). Set. Then, the process proceeds to STEP 26 in FIG. 23, and the current command calculation unit 50 ends the current command value setting process.

  When the calculation of the second dq current setting is impossible in STEP 30, the process proceeds to STEP 31, and the current command calculation unit 50 performs the fourth dq current setting (Id4, Iq4) according to the above equations (24) and (25). ) Is calculated. The fourth dq current setting is a control for obtaining the maximum torque by moving the current vector in the range up to the intersection with the maximum torque / current curve on the current limit circle. Then, the current command calculation unit 50 sets the fourth dq current setting (Id4, Iq4) to the current command value in STEP 32, proceeds to STEP 26 in FIG. 23, and ends the setting process of the current command value.

  Next, when branching from STEP 23 in FIG. 23 to STEP 70 in FIG. 25, the operating condition is such that the dq induced voltage Vo1 is higher than the limit voltage Vom when the first dq current setting (Id1, Iq1) is used. Yes. In this case, the current command calculation unit 50 determines whether it is possible to calculate the fifth dq current setting (Id5, Iq5) that satisfies the relationship of the above equations (7) and (20). It should be noted that the fifth dq current setting can be calculated when the condition of the following equation (39) is satisfied.

When the fifth dq current setting (Id5, Iq5) can be calculated, the process proceeds to STEP 71, and the current command calculation unit 50 calculates the fifth dq current setting (Id5, Iq5). Then, it is determined whether or not the magnitude of the current vector (√ (Id5 ² + Iq5 ² ) corresponding to the second dq determination current of the present invention) by the fifth dq current setting is equal to or less than the limit current Iam.

In STEP 72, if the magnitude of the current vector (√ (Id5 ² + Iq5 ² )) by the fifth dq current setting is equal to or less than the limit current Iam, the process proceeds to STEP73. Then, the current command calculation unit 50 sets the fifth dq current setting (Id5, Iq5) to the current command value, proceeds to STEP 26 in FIG. 23, and ends the current command value setting process.

On the other hand, if the magnitude of the current vector (√ (Id5 ² + Iq5 ² )) by the fifth dq current setting exceeds the limit current Iam in STEP 72, the process branches to STEP 50 in FIG. Then, the current command calculation unit 50 sets the current command value (Id_c, Iq_c) by the processing of STEP50 to STEP52 or STEP50 and STEP60 described above.

  If the calculation of the fifth dq current setting is impossible in STEP 70, the process branches to STEP 80, and the current command calculation unit 50 calculates the sixth dq according to the above equations (32), (33), and (34). The current setting (Id6, Iq6) is calculated. The sixth dq current setting is a current vector at the intersection of the maximum torque / flux curve and the constant induced voltage ellipse.

In subsequent STEP 81, the current command calculation unit 50 determines the magnitude of the current vector according to the sixth dq current setting (Id6, Iq6) (√ (Id6 ² + Iq6 ² ), which corresponds to the third dq determination current of the present invention). Is less than or equal to the limit current Iam. If the magnitude of the current vector (√ (Id6 ² + Iq6 ² )) by the sixth dq current setting (Id6, Iq6) is equal to or less than the limit current Iam, the process proceeds to STEP82. Then, the current command calculation unit 50 sets the sixth dq current setting (Id6, Iq6) to the current command value (Id_c, Iq_c) in the next STEP 82, and proceeds to STEP 26 in FIG. Exit.

On the other hand, when the magnitude of the current vector (√ (Id6 ² + Iq6 ² )) by the sixth dq current setting is larger than the limit current Iam in STEP 81, the process branches to STEP 50 in FIG. The current command values (Id_c, Iq_c) are set by the processing of STEP50 to STEP52 or STEP50 and STEP60 described above.

  In the present embodiment, after the rotor phase difference is controlled according to the optimum Ke for realizing the “maximum efficiency control” by STEP 1 to STEP 4 according to the flowchart of FIG. 5, the STEP 5 is based on the optimum Ke. Although the current command values (Id_c, Iq_c) are set, the effect of the present invention can be obtained even when the processing of STEP5 is not performed.

  In the present embodiment, the first dq current setting, the second dq current setting, the third dq current setting, the fourth dq current setting, and the fifth dq current are performed according to the flowcharts of FIGS. The current command values (Id_c, Iq_c) were calculated by the setting and the sixth dq current setting. However, only the first dq current setting, only the first dq current setting and the second dq current setting, dq current setting, second dq current setting and third dq current setting only, first dq current setting and fourth dq current setting only, first dq current setting and fifth dq current setting only, 1 dq current setting, fifth dq current setting and third dq current setting only, first dq current setting and sixth dq current setting only, first dq current setting and sixth dq current setting, The current command value (Id_c, Iq is determined by any one of the third dq current settings only. The effect of the present invention can also be obtained when calculating _c).

  Further, in this embodiment, as shown in FIG. 1, the rotor phase difference is detected by the phase detector 26, and the detected value Ke_s of the induced voltage constant is calculated from the detected value θd_s of the rotor phase difference. The induced voltage constant Ke may be estimated from the voltage command value Vd_c, the q-axis voltage command value Vq_c, the d-axis current detection value Id_s, and the q-axis current detection value Iq_s.

The control block diagram of the control apparatus of the electric motor of this invention. The block diagram of the electric motor provided with the double rotor shown in FIG. Explanatory drawing of the effect by changing the phase difference of an outer side rotor and an inner side rotor. Explanatory drawing of the effect by changing the phase difference of an outer side rotor and an inner side rotor. The flowchart which shows the whole operation | movement of the control apparatus of an electric motor. Explanatory drawing of the expansion effect of the controllable range of the electric motor by changing a rotor phase difference. Explanatory drawing of the expansion effect of the controllable range of the electric motor by changing a rotor phase difference. Explanatory drawing of the expansion effect of the controllable range of the electric motor by changing a rotor phase difference. Explanatory drawing of the preparation procedure of the map for determining an optimal induced voltage constant. Explanatory drawing of the preparation procedure of the map for determining an optimal induced voltage constant. Explanatory drawing of the preparation procedure of the map for determining an optimal induced voltage constant. The flowchart of the process which calculates an optimal induced voltage constant. Explanatory drawing of the map which converts an induced voltage constant into a rotor phase difference. Explanatory drawing of the method of determining an optimal electric current command value. Explanatory drawing of the method of determining an optimal electric current command value. Explanatory drawing of the method of determining an optimal electric current command value. Explanatory drawing of the method of determining an optimal electric current command value. Explanatory drawing of the method of determining an optimal electric current command value. Explanatory drawing of the method of determining an optimal electric current command value. Explanatory drawing of the method of determining an optimal electric current command value. Explanatory drawing of the method of determining an optimal electric current command value. Explanatory drawing of the method of determining an optimal electric current command value. The flowchart of the process which sets an optimal electric current command value. The flowchart of the process which sets an optimal electric current command value. The flowchart of the process which sets an optimal electric current command value. Explanatory drawing of the necessity for the field weakening control in a drive side and a regeneration side.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electric motor, 2 ... Motor rotating shaft, 10 ... Stator, 11 ... Inner rotor, 11a, 11b ... Permanent magnet, 12 ... Outer rotor, 12a, 12b ... Permanent magnet, 25 ... Actuator, 50 ... Current command calculation part, 80 ... Phase difference control unit, 90 ... Ke command calculation unit, 92 ... Ke calculation unit

Claims (10)

The first rotor and the second rotor having a plurality of field by the permanent magnet, a motor control apparatus for controlling the operation of the rotary motor of the permanent magnet field type that is placed around a rotating shaft,
Rotor phase difference changing means for changing a rotor phase difference which is a phase difference between the first rotor and the second rotor;
An inverter that converts a DC voltage supplied from a DC power source into a polyphase AC voltage and applies it to the armature of the motor;
In an electric motor control device comprising energization control means for controlling a phase current that is a vector sum of currents flowing through armatures of the respective phases of the electric motor via the inverter in accordance with a predetermined torque command,
A rotational speed detection means for detecting the rotational speed of the electric motor;
Based on the output voltage of the DC power supply, the rotational speed of the electric motor, and the torque command, the rotor phase difference is changed so that the efficiency of the electric motor is maximized when obtaining a torque according to the torque command. And a rotor phase difference control means for changing the rotor phase difference by means.   The rotor phase difference control means determines an induced voltage constant that minimizes the loss of the motor with respect to a preset DC voltage supplied to the inverter, the rotation speed of the motor, and the torque of the motor. Applying the output voltage of the DC power source, the rotation speed of the motor detected by the rotation speed detection means, and the torque command to the correlation map to obtain a corresponding induced voltage constant, the acquired induced voltage The motor control device according to claim 1, wherein a rotor phase difference of the motor is changed according to a constant. The electric motor is handled by converting it into an equivalent circuit having a d-axis armature on the d-axis that is the magnetic flux direction of the field and a q-axis armature on the q-axis orthogonal to the d-axis,
The energization control means reduces the difference between the actual value of the d-axis current that is the current flowing through the d-axis armature and the command value, and the actual value and command of the q-axis current that is the current flowing through the q-axis armature. The energization control is performed so as to reduce the difference from the value,
Based on the induced voltage constant of the electric motor according to the rotor phase difference and the angular velocity according to the rotational speed of the electric motor, among the combinations of the d-axis current and the q-axis current that can obtain the torque according to the torque command The combination that minimizes the loss of the electric motor is determined as the first dq current setting, and the d-axis current generated by the first dq current setting and the induced voltage generated in the d-axis armature when the q-axis current is supplied Estimating the induced voltage generated in the q-axis armature based on the induced voltage constant of the electric motor according to the rotor phase difference and the rotational speed of the electric motor,
A first dq determination voltage, which is a vector sum of the estimated induced voltage generated in the d-axis armature and the induced voltage generated in the q-axis armature, is equal to or lower than a limit voltage set according to the output voltage of the DC power supply. And when the first dq determination current, which is the magnitude of the dq-axis current that is the vector sum of the d-axis current and the q-axis current, according to the first dq current setting is equal to or less than a predetermined limit current, Current command setting means is provided which uses the d-axis current set by the first dq current as a command value for the d-axis current and uses the q-axis current set by the first dq current as a command value for the q-axis current. The motor control device according to claim 1, wherein the motor control device is a motor control device. When the first dq determination voltage is equal to or lower than the limit voltage and the first dq determination current is greater than the limit current, the current command setting unit determines that the magnitude of the dq axis current is the limit. Determining whether it is possible to calculate a second dq current setting, which is a combination of a d-axis current and a q-axis current, which is a current and has a maximum torque of the motor,
When the calculation of the second dq current setting is possible, the induced voltage generated in the d-axis armature and the q-axis armature are generated when the d-axis current and the q-axis current are supplied by the second dq current setting. Estimating the induced voltage based on the induced voltage constant of the electric motor according to the rotor phase difference and the rotational speed of the electric motor,
When the second dq determination voltage, which is a vector sum of the induced voltage generated in the estimated d-axis armature and the induced voltage generated in the q-axis armature, is equal to or lower than the limit voltage, the second dq current setting is performed. 4. The motor control device according to claim 3, wherein the d-axis current is used as a command value for the d-axis current, and the q-axis current based on the second dq current setting is used as the command value for the q-axis current.   When the second determination voltage is higher than the limit voltage, the current command setting means has a d-axis current whose magnitude of the dq-axis current is the limit current and whose dq-induced voltage is the limit voltage. It is determined whether or not a third dq current setting that is a combination of q-axis currents can be calculated, and when the third dq current setting can be calculated, the third dq current setting is determined. 5. The motor control device according to claim 4, wherein the d-axis current is used as a command value for the d-axis current, and the q-axis current based on the third dq current setting is used as a command value for the q-axis current. When the first dq determination voltage is equal to or lower than the limit voltage and the first dq determination current is greater than the limit current, the current command setting unit determines that the magnitude of the dq axis current is the limit. Determining whether it is possible to calculate a second dq current setting, which is a combination of a d-axis current and a q-axis current, which is a current and has a maximum torque of the motor,
When the calculation of the second dq current setting is impossible, the combination of the d-axis current and the q-axis current at which the magnitude of the dq-axis current becomes the limit current and the torque of the electric motor becomes maximum is the fourth The dq current setting is determined, and the d-axis current based on the fourth dq current setting is used as the d-axis current command value, and the q-axis current based on the fourth dq current setting is used as the q-axis current command value. 4. The motor control apparatus according to claim 3, wherein When the first dq determination voltage is higher than the limit voltage, the current command setting means obtains a torque according to the torque command and generates an induced voltage generated in the d-axis armature and the q-axis electric machine. A dq induced voltage that is a vector sum of the induced voltage generated in the child is determined whether it is possible to calculate a fifth dq current setting that is a combination of a d-axis current and a q-axis current that is the limit voltage;
When the calculation of the fifth dq current setting is possible and the second dq determination current, which is the magnitude of the dq-axis current by the fifth dq current setting, is equal to or less than the limit current, 4. The electric motor according to claim 3, wherein the d-axis current by setting the dq current of 5 is used as a command value for the d-axis current, and the q-axis current by setting the fifth dq current is used as a command value for the q-axis current. Control device.   The current command setting means can calculate the fifth dq current setting, and when the second dq determination current is larger than the limit current, the magnitude of the dq-axis current is the limit current. And the third dq current setting is determined whether or not it is possible to calculate the third dq current setting that is a combination of the d-axis current and the q-axis current whose dq induced voltage is the limit voltage. Can be used as the d-axis current command value for the third dq current setting and the q-axis current for the third dq current setting as the q-axis current command value. The motor control device according to claim 7. When the first dq determination voltage is higher than the limit voltage, the current command setting means obtains a torque according to the torque command and generates an induced voltage generated in the d-axis armature and the q-axis electric machine. A dq induced voltage that is a vector sum of the induced voltage generated in the child is determined whether it is possible to calculate a fifth dq current setting that is a combination of a d-axis current and a q-axis current that is the limit voltage;
When the calculation of the fifth dq current setting is impossible, the dq induced voltage becomes the limit voltage, and the torque of the motor is maximum with respect to the induced voltage constant of the motor according to the rotor phase difference. The sixth dq current setting that is a combination of the d-axis current and the q-axis current is calculated, and the third dq determination current that is the magnitude of the dq-axis current by the sixth dq current setting is equal to or less than the limit current. The d-axis current based on the sixth dq current setting is used as the d-axis current command value, and the q-axis current based on the sixth dq current setting is used as the q-axis current command value. The motor control device according to claim 3.   The current command setting means cannot calculate the fifth current setting, and when the third dq determination current becomes larger than the limit current, the magnitude of the dq axis current becomes the limit current. In addition, it is determined whether it is possible to calculate a third dq current setting that is a combination of a d-axis current and a q-axis current whose dq induced voltage is the limit voltage, and the third dq current setting When calculation is possible, the d-axis current based on the third dq current setting is used as the d-axis current command value, and the q-axis current based on the third dq current setting is used as the q-axis current command value. The motor control device according to claim 9.

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