JP2016208636A - Motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control device capable of providing a motor with an appropriate current value when starting up an electric vehicle with more simple control.SOLUTION: A motor control device has an inverter, an estimation section and a control section. The inverter drives a motor, the motor having saliency and comprising a rotor. The estimation section estimates a rotation angle of the rotor of the motor. The control section controls the inverter so as to provide the motor with a current value Id for satisfying a following relational expression (Ld-Lq)Id+Φ>0 on the basis of the rotation angle of the rotor estimated by the estimation section when starting up the inverter. Further, Ld is a d-axis inductance of the motor, Lq is a q-axis inductance of the motor, Id is a d-axis current value and Φ is magnetic flux interlinked with an armature at no load.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an electric motor control device.

  Conventionally, an electric motor control device that controls an electric motor without using a rotation angle sensor is known. In this electric motor control device, when the electric vehicle is started, it is unclear whether the motor (wheel) is rotating, so that the control for generating torque by the electric motor may be complicated.

JP 2014-14220 A

  The problem to be solved by the present invention is to provide an electric motor control device capable of giving an appropriate current value to the electric motor when the electric vehicle starts with simpler control.

  The motor control device of the embodiment includes an inverter, an estimation unit, and a control unit. The inverter is an electric motor having saliency and including a rotor, and drives the electric motor. The estimation unit estimates a rotation angle of the rotor of the electric motor. When starting the inverter, the control unit sets the current value Id so as to satisfy the following relational expression (Ld−Lq) Id + Φ> 0 based on the rotation angle of the rotor estimated by the estimation unit. The inverter is controlled so as to be fed to the electric motor. Ld is a d-axis inductance of the motor, Lq is a q-axis inductance of the motor, Id is a d-axis current value, and Φ is a magnetic flux linked to the armature when there is no load.

The block diagram of the electric vehicle 1 containing the electric motor control apparatus of embodiment. 3 is a flowchart showing a flow of processing at start-up executed by the motor control device 30. The figure which shows an example of the relationship between a starting instruction | command, an electric motor electric current, and the rotation speed of the electric motor. 7 is a flowchart showing another example of the flow of processing executed by the electric motor control device 30.

  Hereinafter, an electric motor control device according to an embodiment will be described with reference to the drawings. In the following embodiments, the motor control device will be described as being used for controlling an electric motor for transmitting power to an electric vehicle.

  FIG. 1 is a configuration diagram of an electric vehicle 1 including an electric motor control device of an embodiment. The electric vehicle 1 includes an electric motor 10, wheels 20, a DC power supply 22, a current detection unit 24, and an electric motor control device 30.

  The electric motor 10 is a synchronous motor having saliency (the salient pole ratio is not 1). In the first embodiment, the electric motor 10 is, for example, an embedded magnet type synchronous motor having saliency. The electric motor 10 includes a rotor (not shown) and a stator (not shown). For example, the stator has three-phase power lines of U phase, V phase, and W phase. The rotor includes a permanent magnet disposed in the field space of the stator. The stator generates a rotating magnetic field by the current supplied from the motor control device 30. The direction of the armature flux linkage of the permanent magnet is taken as the d axis, and the axis electrically orthogonal to the d axis is taken as the q axis. When the electric motor 10 is an electric motor having saliency, the inductance value generated on the d-axis is different from the inductance value generated on the q-axis.

  The torque generated by the electric motor 10 is obtained by the outer product of the current flowing through the armature and the magnetic flux interlinked therewith. The torque is determined by absorption and repulsion between the magnetic pole of the permanent magnet of the rotor and the pole of the rotating magnetic field generated by the stator, and the attractive force between the pole and the salient pole of the rotor by the rotating magnetic field of the stator. Is divided into reluctance torque. These torques are transmitted to the wheel 20 via a rotating shaft (not shown) that transmits power.

  The DC power source 22 is, for example, a DC power source obtained from an overhead wire or the like, or a storage battery such as a lithium ion battery. The DC power supply 22 supplies DC power to the inverter 31. In FIG. 1, an overhead line as a power source and a current collector are omitted.

  The current detection unit 24 is a current sensor that detects a current with a Hall IC, for example, a magnetic flux intensity generated by the current. The current detection unit 24 includes a current detection unit 24u and a current detection unit 24w. The current detection unit 24u is attached to a U-phase power line. The current detection unit 24u detects the U-phase current Iu supplied from the inverter 31 to the electric motor 10 via the U-phase power line. The current detection unit 24w is attached to a W-phase power line. The current detection unit 24w detects the W-phase current Iw supplied from the inverter 31 to the electric motor 10 via the W-phase power line.

  The motor control device 30 includes, for example, an inverter 31, a start sequence unit 32, a torque command calculation unit 34, a current command calculation unit 40, a current control unit 46, a first coordinate conversion unit 48, and a PWM control unit 50. A second coordinate conversion unit 52, a pole estimation unit 60, and a rotation speed calculation unit 70. Among these functional units, those excluding the inverter 31 are, for example, software functional units that function by executing a program. Some or all of these functional units may be hardware functional units such as LSI (Large Scale Integration) and ASIC (Application Specific Integrated Circuit). The electric motor control device 30 includes a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), and a flash memory.

  The inverter 31 includes a plurality of switching elements. The inverter 31 converts a DC voltage into a three-phase AC voltage having an arbitrary voltage and an arbitrary frequency by arbitrarily conducting (ON) and blocking (OFF) a plurality of switching elements. The inverter 31 converts DC power into three-phase AC power based on a control signal (for example, PWM (Pulse Width Modulation) signal) output from the first coordinate conversion unit 48 and supplies it to the motor 10. The inverter 31 converts AC regenerative power generated by the motor 10 into DC regenerative power when the motor 10 is in regenerative operation.

  The start sequence unit 32 acquires a start command output by an operation of a master controller (not shown) included in the electric vehicle 1, for example. For example, the start sequence unit 32 determines that a start command has been issued when an arbitrary positive number of notches is acquired from notch zero. The start sequence unit 32 controls each unit of the motor control device 30 so that the motor 10 generates a desired torque when a start command is issued (details will be described later). The torque command calculation unit 34 calculates and outputs a torque command value TmRef according to the start command acquired from the start sequence unit 32.

  The current command calculation unit 40 includes a starting initial current command calculation unit 42 and an optimum current command calculation unit 44. The starting initial current command calculating unit 42 acquires the torque command value TmRef output from the torque command calculating unit 34 when starting the electric vehicle 1. The starting initial current command calculation unit 42 calculates the current amplitude and current phase of the current applied to the electric motor 10 according to the acquired torque command value TmRef, and outputs a current command value IdRef and a current command value IqRef. The current command value IdRef is a command value for the d-axis current. The current command value IqRef is a q-axis current command value, and is determined based on the design and configuration of the electric motor 10.

  The optimum current command calculation unit 44 acquires the torque command value TmRef from the torque command calculation unit 34 after the electric vehicle 1 is started. The torque command value TmRef after starting the electric vehicle 1 is a value corresponding to the number of notches based on the operation of the master controller. The torque command calculation unit 34 calculates the torque command value TmRef based on, for example, the maximum power based on the number of notches input from a master controller (not shown) and the rotation speed ωm of the electric motor 10. The optimum current command calculation unit 44 calculates the current amplitude and phase of the current applied to the electric motor 10 according to the acquired torque command value TmRef, and outputs a current command value IdRef and a current command value IqRef. The current command values output by the starting initial current command calculation unit 42 and the optimum current command calculation unit 44 will be described later.

  Current control unit 46 obtains current command value IdRef and current command value IqRef output from current command calculation unit 40. The current control unit 46 acquires the current values (d-axis current value Id and q-axis current value Iq) detected by the current detection unit 24 and converted by the second coordinate conversion unit 52. The current control unit 46 determines the d-axis voltage command VdRef0 and the q-axis voltage command VqRef0 based on the acquired current command value IdRef, current command value IqRef, and current values (d-axis current value Id and q-axis current value Iq). And output to the first coordinate conversion unit 48.

  The first coordinate conversion unit 48 includes a d-axis voltage command VdRef in which a high-frequency voltage is superimposed by a high-frequency superimposed voltage calculation unit 66 on the d-axis voltage command VdRef0 and the q-axis voltage command VqRef0 output from the current control unit 46. The q-axis voltage command VqRef is acquired. The first coordinate conversion unit 48 converts the acquired d-axis voltage command VdRef and q-axis voltage command VqRef into U-phase, V-phase, and W-phase voltage commands Vu, Vv, and Vw, and outputs them to the PWM control unit 50. .

  The PWM control unit 50 individually compares a preset triangular wave and each phase voltage command Vu, Vv, Vw to generate each phase gate command, and controls each phase switching element constituting the inverter 31. The second coordinate conversion unit 52 converts the U-phase current Iu and the W-phase current Iw detected by the current detection units 24u and w into a d-axis current value Id and a q-axis current value Iq, and the current control unit 46 and Output to the pole estimation unit 60.

  The pole estimation unit 60 includes a high frequency current calculation unit 62, a rotation angle estimation unit 64, a high frequency superimposed voltage calculation unit 66, and a polarity estimation unit 68. The high-frequency current calculation unit 62 extracts a high-frequency current component from the two-phase currents Iu and Iw detected by the current detection unit 24, calculates a time change rate thereof, and outputs the calculated rate of change. The rotation angle estimation unit 64 temporally changes the voltage superimposed on the d-axis voltage command VdRef0 and the q-axis voltage command VqRef0 by the high-frequency superimposed voltage calculation unit 66 and the high-frequency current component calculated by the high-frequency current calculation unit 62. The rotational phase angle θm of the electric motor 10 is estimated based on the rate. The high-frequency superimposed voltage calculation unit 66 outputs a high-frequency voltage having a frequency sufficiently higher than the operating frequency of the electric motor 10 as one or more of the d-axis voltage command VdRef0 and the q-axis voltage command VqRef0 output from the current command calculation unit 40. Superimpose on.

  The polarity estimation unit 68 acquires the d-axis voltage command VdRef and the q-axis voltage command VqRef on which the high-frequency voltage is superimposed by the high-frequency superimposed voltage calculation unit 66. In addition, the polarity estimation unit 68 acquires the d-axis current value Id and the q-axis current value Iq output from the second coordinate conversion unit 52. Based on the acquired d-axis voltage command VdRef and q-axis voltage command VqRef, and the d-axis current value Id and q-axis current value Iq, the polarity estimation unit 68 determines the polarity of the rotor pole (N pole or S pole). Is estimated.

  The rotation speed calculation unit 70 calculates the rotation speed ωm of the rotor of the electric motor 10 based on the temporal change in the estimation result of the rotation angle estimation unit 64.

  FIG. 2 is a flowchart showing a flow of processing at the time of start executed by the motor control device 30. First, the start sequence unit 32 causes the rotation angle estimation unit 64 to estimate the initial rotation phase angle θm of the rotor of the electric motor 10 (step S100). For example, the start sequence unit 32 controls the current control unit 46 so as to apply a minute current to the electric motor 10. The rotation angle estimator 64 changes with time the voltage applied to the d-axis voltage command VdRef0 and the q-axis voltage command VqRef0 by the high-frequency superimposed voltage calculator 66 and the high-frequency current component calculated by the high-frequency current calculator 62. The initial rotational phase angle θm of the electric motor 10 is estimated based on the rate.

  Next, the start sequence unit 32 causes the torque command calculation unit 34 to calculate a torque command value TmRef based on the acquired start command (step S102). Next, the start sequence unit 32 calculates the rotation speed of the electric motor 10 acquired from the rotation speed calculation unit 70, and determines whether or not the calculated rotation speed is equal to or higher than the rotation speed at which the polarity is determined (step S104). . Here, the rotation speed at which the polarity is determined is a rotation speed at which the rotation speed of the electric motor 10 is increased and a sufficient induced voltage is generated to execute the polarity determination.

  When it is determined that the rotational speed is not equal to or higher than the rotational speed at which the polarity is determined, the starting sequence unit 32 causes the starting initial current command calculating unit 42 to set a starting initial current command value to be described later (step S106). As a result, a control signal corresponding to the starting initial current command value is input to the inverter 31. Next, the start sequence unit 32 calculates the rotation number of the electric motor 10 acquired from the rotation number calculation unit 70, and determines whether or not the calculated rotation number is equal to or higher than the rotation number for which polarity determination is performed (step S108). .

  If it is determined that the rotational speed is equal to or higher than the rotational speed at which the polarity is determined, the starting sequence unit 32 causes the polarity estimation unit 68 to estimate the polarity of the rotor pole (N pole or S pole) (step S110). In this case, the start sequence unit 32 stops the start initial current command calculation unit 42 from calculating the start initial current command value. Next, the start sequence unit 32 causes the optimum current command calculation unit 44 to set an optimum current command value based on the polarity of the rotor pole as the estimation result (step S112). As a result, a control signal corresponding to the optimum current command value is input to the inverter 31, and the processing of this flowchart ends.

  The optimum current command value is, for example, a value for realizing the minimum loss of the motor 10, the minimum loss between the motor 10 and the inverter 31, and the minimum current value while maintaining a desired torque. The motor control device 30 may store an optimum current command value table for calculating the optimum current command value in the storage device of the own device. In the optimum current command value table, the torque generation efficiency is the maximum efficiency, for example, the loss of the motor 10 is minimum, the loss between the motor 10 and the inverter 31 is minimum, and the current value is minimum with respect to the desired torque. Are stored in association with each other. The start sequence unit 32 refers to the optimum current command value table and acquires the optimum current command value from the desired torque included in the start command.

Here, the starting initial current command value will be described. The starting initial current command value is a current value for generating a reluctance torque exceeding the magnet torque. The starting initial current command value determines a current value given to the stator via the inverter 31 of the electric motor 10. Hereinafter, the current value given to the stator for the reluctance torque to exceed the magnet torque will be described. Theoretically, when the direction of the armature flux linkage of the permanent magnet is defined as the d axis, it is expressed by the following equation. MOT represents a torque equation (1) generated by the electric motor 10, RlT represents a reluctant torque equation (2), and MgT represents a magnet torque equation (3). Ld is the d-axis inductance, Lq is the q-axis inductance, Id is the d-axis current value, and Iq is the q-axis current value. Further, Φ is a magnetic flux interlinking with the armature when there is no load, and here is an armature interlinking magnetic flux of the permanent magnet.
MOT = RlT + MgT (1)
RlT = (Ld−Lq) Id × Iq (2)
MgT = Φ × Iq (3)
Here, assuming that the polarities of MOT are opposite, the following formula (4) is established.
MgT = −Φ × Iq (4)

Here, assuming that the torque of the electric motor 10 required at the start is Tref (Tref> 0), the following formulas (5) and (6) need to be satisfied in order to secure a torque equal to or higher than Tref.
Tref <(Ld−Lq) Id × Iq−Φ × Iq (5)
Tref <{(Ld−Lq) Id−Φ} × Iq (6)
That is, if the current command value satisfies the following expression (7), the torque of the electric motor 10 required at the time of starting can be obtained.
Tref <{(Ld−Lq) IdRef−Φ} × IqRef (7)

In particular, if the torque of the electric motor 10 required at the time of starting is positive, it can be arranged in the relationship expressed by the following formula (8).
0 <{(Ld−Lq) Id−Φ} × Iq (8)
Considering that Iq> 0 is essential, the following formula (9) is established.
(Ld−Lq) Id + Φ> 0 (9)
That is, if IdRef that is the d-axis current command value is determined so as to satisfy the following expression (10), a positive torque or a torque exceeding zero is generated, and the electric motor 10 does not rotate backward.
(Ld−Lq) IdRef + Φ> 0 (10)

  In addition, when applying to an actual machine, you may consider the influence of magnetic saturation in each formula mentioned above. That is, the magnetic saturation state of the magnetic circuit of the electric motor 10 changes according to the d-axis current value Id, the q-axis current value Iq, the magnet temperature, and the like. That is, the inductance Ld or the inductance Lq changes. The electric motor control device 30 may set conditions for calculating the current command value by analysis according to the operating point of the electric motor 10.

  FIG. 3 is a diagram illustrating an example of the relationship among the start command, the motor current, and the rotation speed of the motor 10. The horizontal axes of the upper, middle, and lower stages in the figure each represent time. The upper vertical axis in the figure shows the output state of the start command acquired by the start sequence unit 32. The state where the start command is output is ON, and the state where the start command is not output is OFF. The middle vertical axis in the figure represents the motor current. Further, the lower part of the figure shows the rotation speed of the electric motor 10.

  In general, when the start sequence unit obtains a start command, the pole is estimated using the salient pole ratio regardless of the rotation speed of the motor, and the magnetic pole of the rotor is determined. In this case, the start sequence unit may control the current command calculation unit so as to cause the current control unit to output the current command value Ix based on the determination result. However, when the rotational speed of the electric motor is not equal to or higher than the rotational speed ωh for determining the polarity, that is, when the electric vehicle is stopped, the electric vehicle may move backward when the current command value Ix is output to the current control unit. This is because, for example, when the determination of the magnetic pole is incorrect, the reluctance torque generated by the starting initial current command value Ix may be lower than the magnet torque and a negative torque may be generated.

  On the other hand, in the embodiment, when the start sequence unit 32 obtains the start command and the rotation speed of the electric motor 10 is not equal to or higher than the rotation speed ωh for determining the polarity, the start control current command value IRef is output to the current control unit 46. The starting initial current command calculation unit 42 is controlled. In this case, the d-axis current command value IdRef of the starting initial current command value IRef is a value satisfying (Ld−Lq) IdRef + Φ> 0 in the above-described equation (9). That is, IdRef is a current value that generates a reluctance torque that exceeds the magnet torque. Thereby, when the electric vehicle 1 is started, the start sequence unit 32 causes the current control unit 46 to output an appropriate start initial current command value IRef, so that the electric vehicle 1 can be prevented from moving backward.

  In the embodiment, when the starting sequence unit 32 determines that the rotation speed of the electric motor 10 is equal to or higher than the rotation speed ωh for determining the polarity, the polarity estimation unit 68 has the polarity of the rotor pole (N pole or S pole). Is estimated. In this case, since the rotation speed increases and the induced voltage is equal to or higher than a predetermined value, the polarity estimation unit 68 can more accurately determine the pole. As a result, the start sequence unit 32 can cause the optimum current command calculation unit 44 to set the optimum current command value based on the estimated polarity of the rotor poles.

  In the embodiment, the electric current value Id corresponding to the starting initial current command value is given to the electric motor 10 at the time of starting, but the same processing may be performed not only at the time of starting but also at a low speed operation. For example, when the rotation speed calculation unit 70 determines that the rotation speed of the electric motor 10 is not equal to or higher than the rotation speed at which the polarity is determined, the start sequence unit 32 causes the start initial current command calculation unit 42 to set the start initial current command value. When the rotational speed calculation unit 70 determines that the rotational speed of the electric motor 10 is equal to or higher than the rotational speed at which the polarity is determined, that is, when it is determined that it is not during low speed operation, the start sequence unit 32 rotates the polarity estimation unit 68. The polarity of the child pole (N pole or S pole) is estimated. Then, the starting sequence unit 32 causes the optimum current command calculation unit 44 to set an optimum current command value based on the polarity of the rotor pole as the estimation result.

  Moreover, the process of the flowchart shown in FIG. 2 may be changed as follows. FIG. 4 is a flowchart showing another example of the flow of processing executed by the motor control device 30. First, as described above, the start sequence unit 32 executes the processing from step S100 to step S106. Next, the start sequence unit 32 determines whether or not a predetermined time has elapsed since the start of the electric motor 10 in accordance with the start initial current command value set in step S106 (step S108 *).

  If it is determined that a predetermined time has elapsed since the start of the electric motor 10 in accordance with the starting initial current command value set in step S106, the starting sequence unit 32 causes the polarity estimating unit 68 to detect the polarity of the rotor (N poles). Alternatively, S pole) is estimated (step S110). Next, the start sequence unit 32 causes the optimum current command calculation unit 44 to set an optimum current command value based on the polarity of the rotor pole as the estimation result (step S112). As a result, a control signal corresponding to the optimum current command value is input to the inverter 31, and the processing of this flowchart ends. In this case, the motor control device 30 does not need to calculate the rotation speed of the electric motor 10 using the rotation angle estimation section 64 and the rotation speed calculation section 70, so the polarity estimation section 68 can be controlled by the pole estimation section 68 with simpler control. It is possible to determine whether or not to estimate the polarity.

  According to the motor control device 30 of the above-described embodiment, when starting the inverter, the start sequence unit 32 is based on the rotation angle of the rotor estimated by the rotation angle estimation unit 64. d-axis inductance Ld−q-axis inductance Lq of the motor × d-axis current value Id + the initial initial current command calculation unit 42 is controlled so as to give the motor a current value Id that satisfies the armature linkage flux Φ> 0 of the permanent magnet. To do. As a result, an appropriate current value can be given to the motor when the electric vehicle starts with simple control that does not require determination of the direction of the magnetic pole (N pole or S pole) of the motor.

(Modification of the embodiment)
Hereinafter, modifications of the embodiment will be described. The modification of the embodiment differs from the embodiment in that a reluctance type synchronous motor is used as the electric motor 10. The rotor of the reluctance type synchronous motor has saliency, the direction in which the magnetic resistance is maximum is the d axis, and the axis that is electrically orthogonal to the d axis is the q axis. The inductance value generated on the d-axis is different from the inductance value generated on the q-axis. Note that the rotor of the reluctance type synchronous motor does not have a permanent magnet. The torque generated by the electric motor 10 is obtained by the outer product of the current flowing through the armature and the magnetic flux interlinked therewith. The torque is generated by the attractive force between the pole due to the rotating magnetic field of the stator and the salient pole of the rotor.

In this case, since the magnet torque is zero, IdRef * may be a value that satisfies the following formula (11).
(Ld−Lq) IdRef *> 0 (11)
The start sequence unit 32 controls the start initial current command calculation unit 42 so that the current control unit 46 outputs IdRef * that satisfies the above formula (11). Accordingly, the start sequence unit 32 can set a current value for causing the electric motor 10 to output an appropriate torque when starting the electric vehicle 1.

  According to the motor control device 30 of the modified example described above, the start sequence unit 32 sets a current value for causing the reluctance type synchronous motor to output an appropriate torque when starting the electric vehicle. As a result, an appropriate current value can be given to the electric motor when the electric vehicle starts with simple control.

  According to at least one embodiment described above, an electric motor having saliency and having a rotor, the inverter (31) driving the motor, and an estimation unit for estimating the rotation angle of the rotor of the electric motor (64) and the rotation angle of the rotor estimated by the estimation unit when starting the inverter, the relational expression (d-axis inductance Ld of the motor−q-axis inductance Lq of the motor) × d-axis current value Id + By providing a control unit (32, 42) for controlling the inverter so as to give the electric current value Id to the electric motor so as to satisfy the magnetic flux Φ> 0 linked to the armature when there is no load, the electric vehicle can be controlled with simpler control. When the motor starts, an appropriate current value can be given to the motor.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Electric motor, 30 ... Electric motor control apparatus, 31 ... Inverter, 34 ... Torque command calculating part, 40 ... Current command value calculating part, 42 ... Starting initial current command calculating part, 44 ... Optimal current command calculating part, 46 ... Current control 60, pole estimation unit, 64 ... rotation angle estimation unit, 68 ... polarity estimation unit

Claims (7)

An electric motor having saliency and including a rotor, and an inverter for driving the electric motor;
An estimation unit for estimating a rotation angle of a rotor of the electric motor;
When starting the inverter, the inverter is controlled so as to give a current value Id to the electric motor so as to satisfy the following relational expression (1) based on the rotation angle of the rotor estimated by the estimation unit. A control unit;
An electric motor control device.
(Ld−Lq) Id + Φ> 0 (1)
Ld: d-axis inductance of the motor Lq: q-axis inductance of the motor Id: d-axis current value Φ: magnetic flux linked to the armature at no load The control unit stops calculating the current value Id based on the relational expression (1) when it is determined that the rotation speed of the electric motor is equal to or greater than a predetermined value based on the estimation result of the estimation unit.
The electric motor control device according to claim 1. The controller stops calculating the current value Id based on the relational expression (1) when it is determined that a predetermined time has elapsed since the start of the electric motor.
The electric motor control device according to claim 1. A pole estimator for estimating the polarity of the pole of the rotor, or when the controller determines that the number of revolutions of the motor has become a predetermined value or more based on an estimation result of the estimator, or the motor When it is determined that a predetermined time has elapsed since starting, the pole estimation unit is made to estimate the polarity of the rotor poles,
The electric motor control device according to claim 1. The control unit is configured to give the electric current value Id based on the relational expression (1) to the electric motor such that the loss in the electric motor is minimum and the efficiency of torque generation by the electric motor is the highest efficiency. Control the inverter,
The electric motor control device according to any one of claims 1 to 4. The motor is an embedded magnet type synchronous motor including a permanent magnet in the rotor and the Φ is a value exceeding zero.
The motor control device according to any one of claims 1 to 5. The electric motor is a reluctance type synchronous electric motor having a rotor that does not have a permanent magnet as the rotor and the Φ is zero.
The electric motor control device according to claim 1.

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