JP5168536B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device for sensorless driving of a brushless motor. The brushless motor is used, for example, as a source for generating a steering assist force in an electric power steering apparatus.

  A motor control device for driving and controlling a brushless DC motor is generally configured to control the supply of motor current according to the output of a position sensor for detecting the rotational position of the rotor. However, the environmental resistance of the position sensor becomes a problem, and the expensive position sensor and the wiring associated therewith hinder the cost reduction and the size reduction. Therefore, a sensorless driving method for driving a brushless DC motor without using a position sensor has been proposed. The sensorless driving method is a method for estimating the phase of the magnetic pole (electrical angle of the rotor) by estimating the induced voltage accompanying the rotation of the rotor.

  Since the induced voltage cannot be estimated when the rotor is stopped and when rotating at a very low speed, the phase of the magnetic pole is estimated by another method. Specifically, as shown in FIG. 2 (a), a high-frequency voltage vector (magnitude) that rotates around the origin of the αβ coordinate, which is a fixed coordinate with the rotation center of the rotor 50 as the origin, along the rotation direction of the rotor 50. Is applied to the U, V, and W phase stator windings 51, 52, and 53. The high-frequency voltage vector is a voltage vector that rotates at a sufficiently high speed with respect to the rotational speed of the rotor 50. Along with the application of the high-frequency voltage vector, current flows through the U, V, and W-phase stator windings 51, 52, and 53. A current vector representing the magnitude and direction of the three-phase current on the αβ coordinate rotates around the origin.

  The inductance of the rotor 50 takes different values for the d-axis, which is the magnetic pole axis along the magnetic flux direction, and the q-axis (axis along the torque direction) orthogonal thereto. For this reason, the magnitude of the current vector is large in the direction close to the d-axis, and is small in the direction close to the q-axis. As a result, as shown in FIG. 2B, the end point of the current vector draws an elliptical locus 55 having the major axis in the d-axis direction of the rotor 50 on the αβ coordinates.

  Therefore, the magnitude of the current vector has a maximum value in the N-pole direction and the S-pole direction of the rotor 50. In other words, the magnitude of the voltage vector changes as shown in FIG. 3 (b), whereas the magnitude of the current vector, as shown in FIG. Have In this case, if the magnitude of the voltage vector is sufficiently large, the inductance of the N pole side of the rotor 50 becomes smaller than that of the S pole side due to the influence of the magnetic saturation of the stator, and the magnitude of the current vector in the N pole direction. Takes the maximum value (see curve L1).

Therefore, a sufficiently large high-frequency voltage vector is applied to specify the maximum of the current vector corresponding to the N pole, and thereafter, a high-frequency voltage vector having a reduced size is applied, based on the maximum value of the current vector. The phase of the rotor 50 can be estimated. More specifically, the phase angle (electrical angle) θ of the rotor 50 becomes θ = Tan ⁻¹ (I by the α-axis component I _α and the β-axis component I _β of the current vector at the maximum value. _β / I _α ).
JP 2004-343963 A Chen Zhen et al., “Position / Velocity Sensorless Control of Cylindrical Brushless DC Motor Using Disturbance Observer and Velocity Adaptive Identification”, IEEJ Transactions D, 118, 7/8, 1998

In a high speed range where the rotor position can be estimated using the induced voltage, it is not appropriate to use the position estimation method using the high frequency exploration voltage. This is because the efficiency may be lowered by the application of the high-frequency exploration voltage, and the control of the motor may be adversely affected.
Therefore, when the rotor is stopped and when rotating at very low speeds, position estimation processing for the low speed range that estimates the rotor position using the high frequency exploration voltage is performed, while in the high speed range, the rotor position is estimated using the induced voltage. It is conceivable to perform position estimation processing.

However, the estimated rotor position obtained by the low-speed region position estimation process and the estimated rotor position obtained by the high-speed region position estimation process do not necessarily match. Therefore, when the low speed range position estimation process and the high speed range position estimation process are switched according to the rotation speed of the motor, the estimated rotor position becomes discontinuous, which may adversely affect the control.
Accordingly, an object of the present invention is to provide a motor control device capable of improving the stability of control at the time of switching between position detection for a low speed region and position detection for a high speed region.

In order to achieve the above object, the invention according to claim 1 is designed to be adapted to a state in which the motor (3) is rotating in a predetermined low speed range, and a low speed range position for obtaining the rotational position of the motor. A detection means (41) and a high-speed position detection means (42) designed to match the state in which the motor is rotating in a predetermined high-speed range that is faster than the low-speed range, and for determining the rotational position of the motor. ), A rotation speed calculation means (22) for calculating the rotation speed of the motor from the rotation position of the motor obtained by the position detection means for the low speed range and the position detection means for the high speed range, and the position for the low speed range The rotational position of the motor is estimated based on the rotational position of the motor obtained by the detecting means and the position detecting means for the high speed range, and the rotational speed calculated by the rotational speed calculating means. Look including the rotational position estimation means (43 to 47) for the rotational position estimating means, the low speed rotational position in fast zone, which is the low speed region position detection means obtaining in between the low speed range and high speed range ( θ ^ _L ) and the high speed rotation position (θ ^ _H ) obtained by the high speed range position detection means are divided internally according to the rotation speed obtained by the rotation speed calculation means, and the internal rotation position (θ ^ _M ) And the first predetermined speed (ω _THE ) in the vicinity of the boundary between the medium speed range and the high speed range, the internal rotation position determined by the internal division means and the high speed range The high-speed rotation position obtained by the position detection means is switched discontinuously, and at the second predetermined speed (ω _TLE ) near the boundary between the low speed range and the medium speed range, the internal rotation position obtained by the internal division means and the The low-speed rotation position required by the low-speed position detection means is switched discontinuously and selected Switching means (44) that outputs as the rotational position (θ ^ _S ), and correction means (45,) that outputs the estimated rotational position (θ ^) that gradually changes by correcting the selected rotational position output by the switching means. 46), and the correction means uses the error between the internal rotation position and the high speed rotation position or the low speed rotation position as an initial correction value so as to converge to zero over time. ) To correct the selected rotational position . The alphanumeric characters in parentheses indicate corresponding components in the embodiments described later. The same applies hereinafter.

According to this configuration, both the low-speed rotation position obtained by the low-speed range position detection means and the high-speed rotation position obtained by the high-speed range position detection means are used, and the motor speed is calculated based on the rotation speed calculated by the rotation speed calculation means. The rotational position is estimated. As a result, instead of simply switching between the low-speed rotation position and the high-speed rotation position, it is possible to estimate the appropriate rotation position by mixing the two, and that there is a discontinuity in the required rotation position. Can be suppressed or prevented. Thereby, it is possible to improve the stability of control when switching between the position detection for the low speed range and the position detection for the high speed range.
In the present invention, in the middle speed range between the low speed range and the high speed range, the low speed rotation position (θ ^ _L ) and the high speed rotation position (θ ^ _H ) are internally divided according to the rotation speed. Since the minute rotation position (θ ^ _M ) is obtained, a reasonable rotation position can be estimated by mixing the low-speed rotation position and the high-speed rotation position.
Furthermore, the switching means can switch the internal rotation position and the high speed rotation position discontinuously, and the internal rotation position and the low speed rotation position can be switched discontinuously, while the selected rotation position output by the switching means. Is corrected by the correcting means, and an estimated rotational position that gradually changes (a change is reduced) is output. Thereby, even when the medium speed region is a narrow speed region, it is possible to suppress a sudden change in the internal rotation position, and the discontinuity associated with the switching can be mitigated by correction by the correction means. Thus, it is possible to improve the stability of control when switching between the position detection for the low speed range and the position detection for the high speed range.

  The invention according to claim 2 further includes motor current detecting means (9) for detecting a motor current flowing through the motor, wherein the low speed range position detecting means is based on the motor current detected by the motor current detecting means. The motor control device according to claim 1, further comprising low-speed range position estimating means (41) for estimating the rotational position of the motor. In this case, motor voltage instruction means (13, 14) for instructing the motor voltage applied to the motor may be further provided, and the rotational position of the motor may be estimated based on the motor current and the motor voltage.

  The invention described in claim 3 further includes motor current detecting means (9) for detecting a motor current flowing through the motor, and motor voltage indicating means (13, 14) for indicating a motor voltage applied to the motor. The high speed range position detecting means includes high speed range position estimating means for estimating the rotational position of the motor based on the motor current detected by the motor current detecting means and the motor voltage indicated by the motor voltage indicating means. It is a motor control device of Claim 1 or 2 containing. For example, the induced voltage of the motor can be estimated based on the motor current and the motor command voltage, and the rotational position of the motor can be estimated based on the estimated induced voltage.

  According to a fourth aspect of the present invention, when the correction means switches the selected rotation position from the internal rotation position to the high speed rotation position, the correction means calculates an error between the internal rotation position and the high speed rotation position. The initial correction value, and when the switching means switches the selected rotation position from the internal rotation position to the low-speed rotation position, an error between the internal rotation position and the low-speed rotation position is used as the initial correction value. A correction value calculation means (45) for obtaining a correction value so as to converge to zero with the passage of time from switching of the selected rotation position, and a selection rotation in which the correction value calculated by the correction value calculation means is output by the switching means. It is a motor control apparatus as described in any one of Claims 1-3 containing the addition means (46) added to a position.

  The invention according to claim 5 is a first control region transition from a control region in which the internal rotation position is the selected rotation position to a control region in which the high speed rotation position is the selected rotation position, or the internal division. Control region transition determining means (S21) for determining whether or not a second control region transition from a control region in which the rotational position is the selected rotational position to a control region in which the low-speed rotational position is the selected rotational position has occurred. And the initial correction value is updated when the first control region transition or the second control region transition occurs, and the initial correction value is set if the first control region transition or the second control region transition does not occur. The motor control device according to any one of claims 1 to 4, further comprising initial correction value updating means (S22) that is not updated.

  According to a sixth aspect of the present invention, the internal dividing means includes the high-speed rotation position θ ^ in a control region in which the motor accelerates from the low-speed range toward the high-speed range. _H , The low-speed rotation position θ ^ _L , And the high-speed rotation position θ ^ _H Using the first internal division coefficient α (where 0 ≦ α) representing the usage rate, the internal rotation position θ ^ _M With the formula θ ^ _M = (1-α) θ ^ _L ・ + Α ・ θ ^ _H In the control region where the motor decelerates from the high speed region toward the low speed region, the high speed rotational position θ ^ _H , The low-speed rotation position θ ^ _L , And the high-speed rotation position θ ^ _H Using the second internal division coefficient β (where α <β ≤ 1) representing the usage rate of the internal rotation position θ ^ _M With the formula θ ^ _M = (1-β) θ ^ _L ・ + Β ・ θ ^ _H It is a motor control device given in any 1 paragraph of Claims 1-5 calculated by these.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram for explaining an electrical configuration of an electric power steering apparatus to which a motor control apparatus according to an embodiment of the present invention is applied. The electric power steering apparatus includes a torque sensor 1 that detects a steering torque applied to a steering wheel of a vehicle, an electric motor 3 that applies a steering assist force to a steering mechanism 2 of the vehicle, and a motor control that drives and controls the electric motor 3. And a device 5. The motor control device 5 drives the electric motor 3 in accordance with the steering torque detected by the torque sensor 1, thereby realizing appropriate steering assistance according to the steering situation. In this embodiment, the electric motor 3 is a three-phase brushless DC motor, and as illustrated schematically in FIG. 2A, the rotor 50 as a magnetic field and U-phase, V-phase, and W-phase stator windings. Lines 51, 52, and 53 are provided. The electric motor 3 may be an inner rotor type in which a stator is disposed outside the rotor, or may be an outer rotor type in which a stator is disposed inside a cylindrical rotor.

  The motor control device 5 includes a microcomputer 7, a drive circuit (inverter circuit) 8 that is controlled by the microcomputer 7 and supplies electric power to the electric motor 3, and currents that flow through the stator windings of each phase of the electric motor 3. And a current sensor 9 for detection. The microcomputer 7 includes a CPU and a memory (such as a ROM and a RAM), and functions as a plurality of function processing units by executing a predetermined program. The plurality of function processing units include a current command value generation unit 11, a PI (proportional integration) control unit 12, an instruction voltage generation unit 13, a γδ / αβ coordinate conversion unit 14, and an αβ / UVW coordinate conversion unit 15. A PWM control unit 16, a UVW / αβ coordinate conversion unit 17, an αβ / γδ coordinate conversion unit 18, a deviation calculation unit 19, a position estimation unit 21, a rotation speed estimation unit 22, and a high frequency voltage generation unit 23. And.

The current command value generation unit 11 generates a command value I _d ^* for the d-axis current component along the rotor magnetic pole direction of the electric motor 3 and a command value I _q ^* for the q-axis current component orthogonal to the d axis. Hereinafter, these are collectively referred to as “current command value I _dq ”. However, the dq coordinate plane is a plane along the rotation direction of the rotor 50, and the d axis and the q axis define a rotation coordinate system that rotates together with the rotor 50 (see FIG. 2).

When the current command value I ^* representing the amplitude of the current (sine wave current) to be applied to the U phase, V phase and W phase of the electric motor 3 is used, the d axis current command value I _d ^* and the q axis current command value I _q ^* Is expressed by the following equations (1) and (2).

したがって、電流指令値生成部１１は、ｄ軸電流指令値Ｉ_d ^*＝０を生成する一方で、トルクセンサ１によって検出される操舵トルクに応じたｑ軸電流指令値Ｉ_q ^*を生成する。より具体的には、操舵トルクに対応したｑ軸電流指令値Ｉ_q ^*を記憶したマップ（テーブル）を用いてｑ軸電流指令値Ｉ_q ^*が生成されるようになっていてもよい。電動モータ３が発生するトルクは、モータ電流に対応するから、電流指令値Ｉ_dqは、電動モータ３から発生させるべきトルクを指令するための「トルク指令値」と言い換えることもできる。

Therefore, the current command value generation unit 11 generates the d-axis current command value I _d ^* = 0, while generating the q-axis current command value I _q ^* corresponding to the steering torque detected by the torque sensor 1. More specifically, the q-axis current command value I _q ^* may be generated using a map (table) that stores the q-axis current command value I _q ^* corresponding to the steering torque. Since the torque generated by the electric motor 3 corresponds to the motor current, the current command value I _dq can be rephrased as a “torque command value” for commanding the torque to be generated from the electric motor 3.

The current sensor 9 detects the U-phase current I _U , the V-phase current I _V and the W-phase current I _w of the electric motor 3 (hereinafter, collectively referred to as “three-phase detection current I _UVW ”). The detected value is given to the UVW / αβ coordinate converter 17.
The UVW / αβ coordinate conversion unit 17 converts the three-phase detection current I _UVW into the currents I _α and I _β on the two-phase fixed coordinate system (hereinafter, collectively referred to as “two-phase detection current I _αβ ”). Convert coordinates to. The two-phase fixed coordinate system is a fixed coordinate system in which the α axis and the β axis orthogonal to the rotation center of the rotor 50 are defined (see FIG. 2). The coordinate-converted two-phase detection current I _αβ is given to the αβ / γδ coordinate conversion unit 18.

The αβ / γδ coordinate conversion unit 18 converts the two-phase detection current I _αβ into a rotational coordinate system (γ−) according to the rotor rotational position θ ^ estimated by the position estimation unit 21 (hereinafter referred to as “estimated rotational position θ ^”). The coordinates are converted into currents I _γ and I _δ on δ) (hereinafter referred to as “detection current I _γδ ” collectively). This rotational coordinate system (γ−δ) is a rotational coordinate system defined by the γ axis along the rotor magnetic pole direction and the δ axis orthogonal to the γ axis when the rotor 50 is at the estimated rotational position θ ^. is there. When the estimated rotational position θ ^ has no error and coincides with the actual rotor rotational position, the dq rotational coordinate system and the γδ rotational coordinate system coincide.

The detected current I _γδ is given to the deviation calculating unit 19. The deviation calculator 19 calculates a deviation of the γ-axis current I _{γ with} respect to the d-axis current command value I _d ^* and a deviation of the δ-axis current I _{δ with} respect to the q-axis current command value I _q ^* . These deviations are given to the PI control unit 12 and are each subjected to PI calculation processing. Then, in accordance with these calculation results, the command voltage generator 13 generates a γ-axis command voltage V _γ ^* and a δ-axis command voltage V _δ ^* (hereinafter referred to as “command voltage V _γδ ” when these are collectively referred to). It is generated and given to the γδ / αβ coordinate converter 14.

The γδ / αβ coordinate conversion unit 14 converts the γ-axis instruction voltage V _γ ^* and the δ-axis instruction voltage V _δ ^* into an α-axis instruction voltage V _α ^* and a β-axis instruction voltage V _β that are instruction voltages in the two-phase fixed coordinate system. ^* (Hereinafter, these are collectively referred to as “two-phase indicating voltage V _αβ ”). The two-phase instruction voltage V _αβ is given to the αβ / UVW coordinate conversion unit 15.
The αβ / UVW coordinate converter 15 converts the α-axis command voltage V _α ^* and the β-axis command voltage V _β ^* into the command voltages of the three-phase fixed coordinate system, that is, the command voltages V _U ^{* of the} U phase, V phase, and W phase , V _V ^* , V _W ^* (hereinafter collectively referred to as “three-phase indicating voltage V _UVW ”).

The PWM control unit 16 generates a drive signal having a duty ratio controlled according to the three-phase instruction voltages V _U ^* , V _V ^* , and V _W ^* and supplies the drive signal to the drive circuit 8. Thus, a voltage is applied to each phase of the electric motor 3 with a duty ratio corresponding to the instruction voltages V _U ^* , V _V ^* , and V _W ^* of the corresponding phase.
With such a configuration, when a steering torque is applied to a steering wheel (not shown) as an operation member coupled to the steering mechanism 2, this is detected by the torque sensor 1. Then, the current command value generation unit 11 generates a current command value I _dq corresponding to the detected steering torque. A deviation between the current command value I _dq and the detected current I _γδ is obtained by the deviation calculation unit 19, and PI calculation is performed by the PI control unit 12 so as to lead this deviation to zero. The command voltage V _γδ corresponding to the calculation result is generated by the command voltage generator 13 and converted into the three-phase command voltage V _UVW through the coordinate converters 14 and 15. Then, the drive circuit 8 operates with a duty ratio corresponding to the three-phase instruction voltage V _UVW by the action of the PWM control unit 16, whereby the electric motor 3 is driven, and an assist torque corresponding to the current command value I _dq is generated. The steering mechanism 2 will be given. Thus, steering assistance can be performed according to the steering torque. The three-phase detection current I _UVW detected by the current sensor 9 passes through the coordinate conversion units 17 and 18, and the detection current I _γδ expressed in the rotating coordinate system (γ−δ) so as to correspond to the current command value I _dq. After being converted to, it is given to the deviation calculator 19.

In order to perform coordinate conversion between the rotating coordinate system and the fixed coordinate system, a phase angle (electrical angle) θ representing the rotational position of the rotor 50 is required. An estimated rotational position θ ^ representing this phase angle is generated by the position estimation unit 21 and is given to the γδ / αβ coordinate conversion unit 14 and the αβ / γδ coordinate conversion unit 18.
The high-frequency voltage generator 23 functions as a search voltage application unit that applies a search voltage to the electric motor 3 in order to estimate the phase angle θ of the rotor 50 when the rotor 50 is stopped and when rotating at a very low speed (250 rpm or less). . The high-frequency voltage generation unit 23 uses a high-frequency sine voltage (see FIG. 3B) having a sufficiently high frequency (for example, 200 Hz) as compared with the rated frequency of the electric motor 3 as an exploration voltage. Voltage command values to be applied to the phase, V-phase, and W-phase stator windings 51, 52, 53 are generated and provided to the PWM control unit 16. More specifically, V-W phase energization, W-U phase energization, and U-V phase energization are sequentially repeated by applying a high-frequency voltage having a duty ratio that does not cause the rotor 50 to rotate. A high frequency voltage vector that spatially rotates around the rotation center of the rotor 50 is applied. This high-frequency voltage vector is a voltage vector having a constant magnitude that rotates at a constant speed around the origin of αβ coordinates, which are fixed coordinates with the rotation center of the rotor 50 as the origin (see FIG. 2A).

The high frequency voltage generator 23 generates a command value for applying the high frequency voltage (search voltage) as described above and applies it to the PWM controller 16 when the rotor 50 stops and rotates at a very low speed. When the rotation of the rotor 50 becomes sufficiently fast (for example, exceeding 250 rpm), the high frequency voltage generator 23 stops generating the high frequency voltage command.
The position estimation unit 21 estimates the rotational position of the rotor 50 based on the motor current flowing through the electric motor 3 and the motor voltage applied to the electric motor 3. The position estimation unit 21 includes a low speed region position estimation unit 41, a high speed region position estimation unit 42, an internal division processing unit 43, a switching unit 44, a correction value calculation unit 45, an addition unit 46, A fraction coefficient calculation unit 47.

The low speed range position estimation unit 41 is designed to be adapted to the position estimation of the rotor 50 when the electric motor 3 is stopped and when rotating at a very low speed (for example, 0 to 100 rpm), and the UVW / αβ coordinate conversion unit 17. The rotational position of the rotor 50 is estimated on the basis of the two-phase detection current I _αβ output from the two-phase instruction voltage V _αβ generated by the γδ / αβ coordinate converter 14.
The high speed range position estimation unit 42 is designed to be adapted to position estimation of the rotor 50 when the electric motor 3 rotates at high speed (for example, 200 rpm or more), and the two-phase output from the UVW / αβ coordinate conversion unit 17. The rotational position of the rotor 50 is estimated based on the detected current I _αβ and the two-phase command voltage V _αβ generated by the γδ / αβ coordinate converter 14.

The internal division processing unit 43 internally divides the low speed estimated rotational position θ ^ _L obtained by the low speed region position estimating unit 41 and the high speed estimated rotational position θ ^ _H obtained by the high speed region position estimating unit 42. Thus, the estimated internal rotation position θ ^ _M is obtained. A first internal division coefficient α and a second internal division coefficient β used for internal division processing in the internal division processing section 43 are obtained by an internal division coefficient calculating section 47.

The switching unit 44 selects any one of the low-speed estimated rotation position θ ^ _L , the high-speed estimated rotation position θ ^ _H, and the internal component estimated rotation position θ ^ _M. The addition unit 46 adds the correction value θc calculated by the correction value calculation unit 45 to the selected estimated rotation position (selected estimated rotation position) θ ^ _S , and the estimated rotation position θ ^ (= θ ^ _S + θc) is obtained.
The rotational speed estimator 22 generates the estimated rotational speed ω ^ (= Δθ ^) of the rotor 50 by obtaining the difference Δθ ^ of the estimated rotational position θ ^ given every predetermined control period from the position estimator 21. .

FIG. 4 is a block diagram for explaining a configuration example of the low-speed range position estimation unit 41. The low speed range position estimation unit 41 includes a high frequency response extraction unit 38 and a rotor position estimation unit 39. The high-frequency response extraction unit 38 is supplied with the two-phase detection current I _αβ output from the UVW / αβ coordinate conversion unit 17. The high frequency response extraction unit 38 is, for example, a high-pass filter, and executes a filter process that extracts a frequency component corresponding to the frequency of the high frequency voltage generated by the high frequency voltage generation unit 23 from the output signal of the UVW / αβ coordinate conversion unit 17. . The rotor position estimation unit 39 estimates the rotor phase angle θ based on the high frequency component extracted by the high frequency response extraction unit 38. This estimation method is as described above with reference to FIGS. However, in this embodiment, the low-speed estimated rotational position θ ^ _L is obtained according to the following equation (3) using the two-phase indicating voltages V _α and V _β when the magnitude of the current vector takes a maximum value. It has become.

θ ^ _L = Tan ⁻¹ (V _β / V _α ) (3)
Of course, as described above, the low-speed estimated rotational position θ ^ _L can be obtained by θ ^ _L = Tan ^-1 ( _Iβ / _Iα ).
FIG. 5 is a block diagram illustrating a configuration example of the high speed region position estimation unit 42. The high speed region position estimation unit 42 includes a signal processing unit 48 and a rotor position estimation unit 49. The signal processing unit 48 includes a voltage filter 31 configured with a low-pass filter that removes high-frequency components of the two-phase indication voltage V _αβ and a low-pass filter that removes high-frequency components of the two-phase detection current I _αβ. Current filter 32. The rotor position estimation unit 49 is supplied with the two-phase command voltage V _αβ and the two-phase detection current I _αβ after the signal processing (filtering) by the signal processing unit 48. The rotor position estimation unit 49 is based on a motor model that is a mathematical model of the electric motor 3, and a disturbance observer 25 that estimates the induced voltage of the electric motor 3 as a disturbance, and a high-frequency component from the estimated induced voltage output by the disturbance observer 25. Based on the estimated value filter 26 constituted by the low-pass filter to be removed and the estimated induced voltage (value after filtering) output from the estimated value filter 26, the high-speed estimated rotational position θ ^ _H of the rotor 50 is generated. And an estimated position generation unit 27. Then, the two-phase indication voltage V _αβ filtered by the voltage filter 31 of the signal processing unit 48 and the two-phase detection current I _αβ filtered by the current filter 32 are respectively input to the disturbance observer 25 of the rotor position estimation unit 49. It has come to be.

FIG. 6 is a block diagram for explaining an example of the disturbance observer 25 and a configuration related thereto. A motor model that is a mathematical model of the electric motor 3 can be expressed as, for example, (R + pL) ⁻¹ . Here, R is an armature winding resistance, L is an αβ axis inductance, and p is a differential operator. It can be considered that the two-phase command voltage V _αβ and the induced voltage E _αβ (α-axis induced voltage E _α and β-axis induced voltage E _β ) are applied to the electric motor 3.

The disturbance observer 25 receives the two-phase detection current I _αβ as an input, and an inverse motor model (inverse model of the motor model) 35 that estimates the motor voltage, and the motor voltage estimated by the inverse motor model 35 and the two-phase indication voltage V _αβ. And a voltage deviation calculation unit 36 for obtaining the deviation. The voltage deviation calculator 36 obtains a disturbance with respect to the two-phase command voltage V _αβ , and as is apparent from FIG. 6, this disturbance is an estimated value E ^ _αβ (α-axis induced voltage estimation corresponding to the induced voltage E _αβ. The value E ^ _α and the β-axis induced voltage estimated value E ^ _β (hereinafter collectively referred to as “estimated induced voltage E ^ _αβ ”) The reverse motor model 35 is represented by R + pL, for example.

As described above, in this embodiment, the disturbance observer 25 is configured to obtain the estimated induced voltage E ^ _αβ using the instruction voltage V _αβ and the detected current I _αβ of the two-phase fixed coordinate system. The induced voltage can be estimated without being affected by the speed. Thereby, it can contribute to the improvement of the rotor rotational position estimation accuracy of the electric motor 3 used for the electric power steering device in which the rotational speed fluctuation is likely to occur.

The estimated value filter 26 can be configured by, for example, a low-pass filter represented by a / (s + a). a is a design parameter, and the cut-off frequency ω _c of the estimated value filter 26 is determined by the design parameter a.
The induced voltage E _αβ can be expressed by the following equation (4). However, K _E is an induced voltage constant, θ is a rotor rotational position, and ω is a rotor rotational speed.

したがって、推定誘起電圧Ｅ^_αβが求まれば、次の(5)式に従って、高速推定回転位置θ^_Hが求まる。この演算が、推定位置生成部２７によって行われるようになっている。

Therefore, if the estimated induced voltage E ^ _αβ is obtained, the high-speed estimated rotational position θ ^ _H is obtained according to the following equation (5). This calculation is performed by the estimated position generation unit 27.

図７は、内分処理部４３および切り換え部４４による処理を説明するための制御領域図であり、横軸は電動モータ３の回転速度を表し、縦軸は、高速域用位置推定部４２によって求められる高速推定回転位置θ^_Hの使用率を表している。

FIG. 7 is a control region diagram for explaining the processing by the internal division processing unit 43 and the switching unit 44, where the horizontal axis represents the rotation speed of the electric motor 3, and the vertical axis represents the high speed range position estimation unit 42. This shows the usage rate of the required high-speed estimated rotational position θ ^ _H.

The internal division processing unit 43 and the switching unit 44 perform different operations depending on which of the four control areas the current state is included in. The four control areas are a low speed area I, a low speed → high speed switching area II, a high speed area III, and a high speed → low speed switching area IV. The speed range of the rotational speed ω of the electric motor 3 is a low speed range (ω ≦ ω _TL ) from the stop state to the first threshold value ω _TL , the first threshold value ω _TL to the second threshold value ω _TH (where ω _TH > ω _TL ) Medium speed range (ω _TL <ω ≦ ω _TH ) and high speed range (ω _TH <ω) exceeding the second threshold value ω _TH .

  The low speed range position estimation unit 41 is designed to be able to estimate the rotor rotational position within a predetermined accuracy range in the low speed range and the medium speed range. Further, the high speed range position estimation unit 42 is designed to be able to estimate the rotor rotational position within a predetermined accuracy range in the medium speed range and the high speed range. Therefore, in the medium speed range, both the low speed range position estimation unit 41 and the high speed range position estimation unit 42 can perform the rotor position estimation calculation, but these calculation results do not necessarily match. Rather, there is usually a wrinkle between the results of both operations. Further, the “medium speed range” where the calculation results of both the low speed range position estimation unit 41 and the high speed range position estimation unit 42 are within the predetermined accuracy range is not necessarily wide.

The acceleration process of the electric motor 3, a state in which the rotational speed of the electric motor 3 is in the speed range from a stopped state until the threshold omega _TL is the low speed range I, the rotational speed threshold ω _TL ~ω _THE electric motor 3 (provided that , Ω _THE > ω _TH ) is a low speed → high speed switching region II, and a state where the rotational speed of the electric motor 3 is in a speed region equal to or higher than the threshold ω _THE is a high speed region III. On the other hand, in the deceleration process of the electric motor 3, the state in which the rotational speed of the electric motor 3 is in the speed range equal to or higher than ω _TH is the high speed region III, and the rotational speed of the electric motor 3 is ω _TLE to ω _TH (however, ω _TLE The state in the speed range of <ω _TL ) is the high speed → low speed switching region IV, and the state in which the rotation speed of the electric motor 3 is in the speed region lower than ω _TLE is the low speed region I.

If the electric motor 3 is decelerated in the state of low-speed → high speed switching region II, control area at that time, i.e., is held in the low-speed → high speed switching region II, if the deceleration to the threshold omega _TL, to the low-speed region I Transition. Similarly, when the electric motor 3 turns to acceleration in the state of the high speed → low speed switching region IV, if it is held in the control region at that time, that is, the high speed → low speed switching region IV and accelerates to the threshold value ω _THE , Transition to high speed region III.

Similarly, when the electric motor 3 starts to decelerate in the speed range of the thresholds ω _TLE to ω _TL in the low speed region I, the low speed region I that is the control region at that time is held. Further, when the electric motor 3 starts to accelerate in the speed range of the thresholds ω _TH to ω _{THE in} the high speed region III, the electric motor 3 is held in the high speed region III that is the control region at that time.
In the low speed region I, the switching unit 44 selects and outputs the low speed estimated rotational position θ ^ _L obtained by the low speed region position estimating unit 41. Therefore, the usage rate of the high-speed estimated rotational position θ ^ _H is zero. In the low speed → high speed switching region II and the high speed → low speed switching region IV, the switching unit 44 selects and outputs the estimated internal rotation position θ ^ _M obtained by the internal division processing unit 43. In the high speed region III, the switching unit 44 selects and outputs the high speed estimated rotational position θ ^ _H obtained by the high speed region position estimating unit 42. Therefore, the usage rate of the high-speed estimated rotational position θ ^ _H is “1” (100%).

Therefore, the control areas in which the internal processing unit 43 substantially functions are the low speed → high speed switching area II and the high speed → low speed switching area IV. The internal division processing unit 43 obtains an estimated internal rotation position θ ^ _M according to the following equation (6) in the low speed → high speed switching region II, and in the high speed → low speed switching region IV, the internal division is calculated according to the following equation (7). Find the estimated rotational position θ ^ _M.
θ ^ _M = (1-α) · θ ^ _L + α · θ ^ _H (6)
θ ^ _M = (1-β) · θ ^ _L + β · θ ^ _H (7)
The first internal division coefficient α and the second internal division coefficient β are calculated by the internal division coefficient calculation unit 47, and these represent the usage rate of the high-speed estimated rotational position θ ^ _H. (1-α) and (1-β) represent the usage rate of the low-speed estimated rotational position θ ^ _L. The first internal division coefficient α is smaller than the second internal division coefficient β. In the low speed → high speed switching region II, the ratio of the low speed estimated rotational position θ ^ _L in the internal division processing is large, and in the high speed → low speed switching region IV, The ratio of the high-speed estimated rotational position θ ^ _H in the internal processing is increased. The first internal division coefficient α and the second internal division coefficient β are variably set according to the estimated rotational speed ω ^. More specifically, the first and second internal division coefficients α and β are calculated by the internal division coefficient calculation unit 47 so as to decrease as the estimated rotational speed ω ^ increases, and are given to the internal division processing unit 43. It is like that.

As understood from FIG. 7, the internal estimated rotational position θ ^ _{M at} the threshold ω _THE for switching from the low speed → high speed switching region II to the high speed region III is the high speed estimated rotation obtained by the high speed region position estimation unit 42. It does not coincide with the position theta ^ _H, the threshold omega _tHE, selected estimated rotational position theta ^ _S outputted from the switching unit 44 becomes discontinuous. Similarly, the internal estimated rotational position θ ^ _M in the threshold value _TLE for switching from the high speed → low speed switching region IV to the low speed region I matches the low speed estimated rotational position θ ^ _{L obtained by the} low speed region position estimation unit 41. without the in threshold omega _tHE, selected estimated rotational position theta ^ _S outputted from the switching unit 44 becomes discontinuous.

The internal estimated rotational position θ ^ _M may be obtained so that such discontinuity does not occur, but as described above, the intermediate speed range is not necessarily wide so that the internal estimated rotational position θ ^ _M does not change suddenly. In order to achieve this, it is preferable to allow the discontinuity.
Then, the discontinuity of the selected estimated rotation position θ ^ _S is alleviated by the functions of the correction value calculation unit 45 and the addition unit 46.

FIG. 8 is a diagram for explaining the functions of the correction value calculation unit 45 and the addition unit 46. FIG. 8A shows an example of the time change of the position correction value θc obtained by the correction value calculation unit 45. 8 (b) shows an example of the temporal change of the estimated rotational position θ ^ when the rotational speed of the electric motor 3 is constant, and FIG. 8 (c) shows the estimated rotational position θ when the electric motor 3 is accelerating. An example of a time change of ^ is shown.
When the control region is switched from the low speed → high speed switching region II to the high speed region III, the correction value calculation unit 45 detects an error θ ^ _M −θ between the internal estimated rotational position θ ^ _M and the high speed estimated rotational position θ ^ _H. ^ _H is determined as the initial correction value θε. Then, using this initial correction value θε as an initial value, a correction value θc is obtained so as to converge to zero with the passage of time with a predetermined time constant (FIG. 8A). This correction value θc is added to the selected estimated rotational position θ ^ _S by the adder 46, thereby obtaining an estimated rotational position θ ^ obtained by correcting the selected estimated rotational position θ ^ _S.

If the rotational speed of the electric motor 3 is constant, the estimated rotational position θ ^ changes in proportion to the passage of time as shown in FIG. 8 (b). In this state, if the control region is switched from the low speed → high speed switching region II to the high speed region III, the selected estimated rotational position θ ^ _S is changed from the internal estimated rotational speed θ ^ _M to the high speed estimated rotational position θ ^ _H. A discontinuity occurs when switching to Therefore, when the estimated rotational position θ ^ is obtained by adding the position correction value θc to the selected estimated rotational position θ ^ _S , the estimated rotational position θ ^ is determined from the internal estimated rotational position θ ^ _M after the control region is switched. It converges gradually to the high-speed estimated rotational position θ ^ _H , and no discontinuity occurs.

FIG. 8 (c) shows an example of the temporal change of the estimated rotational position θ ^ when the electric motor 3 is accelerating. As in the case of FIG. 8 (b), when the control area is switched from the low speed → high speed switching area II to the high speed area III, the selected estimated rotational position θ ^ _S is estimated at the high speed from the internal estimated rotational position θ ^ _M. A discontinuity occurs when switching to the rotational position θ ^ _H. Therefore, by adding the position correction value θc to the selected estimated rotational position θ ^ _S to obtain the estimated rotational position θ ^, the estimated rotational position θ ^ is changed from the internal estimated rotational position θ ^ _M to the high-speed estimated rotational position θ ^. It gradually converges to _H and no discontinuity occurs.

The correction value calculation unit 45 may be configured to obtain the position correction value θc based on the initial correction value θε and the estimated rotational speed ω ^. That is, when switching from low-speed → high speed switching region II to the high speed range III, the region exceeding the threshold omega _THE, so as to suppress the discontinuity of the selected estimated rotational position theta ^ _S before and after the switching, the estimated rotational speed A correction value θc corresponding to ω ^ may be determined. Similarly, when switching from the high-speed to low-speed switching region IV to the low-speed region I, in the region below the threshold ω _TLE , the estimated rotation is controlled so as to suppress the discontinuity of the selected estimated rotational position θ ^ _S before and after switching. A correction value θc corresponding to the speed ω ^ may be determined.

FIG. 9 is a flowchart for explaining the flow of the rotor rotational position estimation calculation by the microcomputer 7, and mainly shows the flow of processing repeatedly executed by the position estimation unit 21 for each control cycle.
The two-phase detection current I _αβ calculated by the UVW / αβ coordinate conversion unit 17 and the two-phase indication voltage V _αβ calculated by the γδ / αβ coordinate conversion unit 14 are the position estimation unit 41 for the low speed region and the position estimation for the high speed region. Input to the unit 42 (step S1).

Next, it is determined whether the control area is the aforementioned low speed area I, low speed → high speed switching area II, high speed area III, or high speed → low speed switching area IV (steps S2, S3, S4). However, the initial initial control area where control is started is the low speed area I.
When the control area is the low speed area I (step S2: YES), the low speed range position estimation unit 41 obtains the low speed estimated rotation position θ ^ _L (step S5), and this low speed estimated rotation position θ ^ _L is selected. The estimated rotational position θ ^ _S is generated from the switching unit 44 (step S6).

When the control region is the low speed → high speed switching region II (step S3: YES), the low speed region position estimation unit 41 obtains the low speed estimated rotation position θ ^ _L (step S7) and the high speed region position estimation unit. 42 is used to obtain the high-speed estimated rotational position θ ^ _H (step S8). Then, the internal division processing unit 43 obtains internal dividing points of the low speed estimated rotational position θ ^ _L and the high speed estimated rotational position θ ^ _H , and calculates the internal fraction estimated rotational position θ ^ _M (step S9). The selected estimated rotational position θ ^ _S is generated from the switching unit 44 (step S10).

When the control region is the high-speed region III (step S4: YES), the high-speed region position estimation unit 42 obtains the high-speed estimated rotation position θ ^ _H (step S11), and this high-speed estimated rotation position θ ^ _H is selected. The estimated rotational position θ ^ _S is generated from the switching unit 44 (step S12).
When the control region is the high-speed to low-speed switching region IV (step S4: NO), the low-speed region position estimation unit 41 obtains the low-speed estimated rotation position θ ^ _L (step S13), and the high-speed region position estimation unit 42. Is used to obtain the high-speed estimated rotational position θ ^ _H (step S14). Based on these, the internal division processing unit 43 obtains the internal division estimated rotational position θ ^ _M (step S15), and this is generated from the switching unit 44 as the selected estimated rotational position θ ^ _S (step S16).

On the other hand, the correction value calculation unit 45 obtains the position correction value θc based on the initial correction value θε and the elapsed time t (or estimated rotational speed ω ^) from the switching of the control region (step S17). The obtained position correction value θc is added to the selected estimated rotational position θ ^ _S by the adding unit 46, thereby obtaining the estimated rotational position θ ^ (step S18).
The rotational speed estimator 22 calculates a difference Δθ between the estimated rotational position θ ^ (n) obtained in the current control cycle n and the estimated rotational position θ ^ (n-1) obtained in the previous control cycle n−1. θ ^ (n) −θ ^ (n−1)) is obtained and generated as the estimated rotational speed ω ^ (step S19).

The microcomputer 7 further determines a control region for processing in the next control cycle n + 1 based on the current control region and the obtained estimated rotational speed ω ^ (step S20). When the control area determined in step S20 is the high speed area III or the low speed area I, the microcomputer 7 further changes the control area from the low speed → high speed switching area II to the high speed area III, or the high speed → low speed switching. It is determined whether a transition of the control area from the area IV to the low speed area I has occurred (step S21). When such a transition of the control region occurs (step S21: YES), the correction value calculation unit 45 sets the low-speed estimated rotation position θ ^ _L and the high-speed estimated rotation position θ ^ _H obtained in the current control cycle. Based on this, an initial correction value θε is obtained (step S22). On the other hand, if the transition of the control region as described above does not occur (step S21: NO), the correction value calculation unit 45 does not update the initial correction value θε. The initial value of the initial correction value θε is “0”.

FIG. 10 is a block diagram for explaining a configuration example of the internal coefficient calculation unit 47. The internal division coefficient calculation unit 47 includes a first internal division coefficient generation unit 61 that generates a first internal division coefficient α used for internal division processing in the low speed → high speed switching area II, and an internal division coefficient in the high speed → low speed switching area IV. And a second internal coefficient generation unit 62 that generates a second internal coefficient β used for the minute processing. The first division coefficient generation unit 61 has a lower limit value α _L (for example, α _L = 0) of the first division coefficient α and an upper limit value α _U (for example, α _U = 0.4) of the first division coefficient α. first switching signal generator 63, a first low-pass filter 65 to perform low-pass filtering on the signal alpha ₀ of the first switching signal generator 63 generates to generate either as original signals alpha ₀ and And. The second internal coefficient generation unit 62 includes a lower limit value β _L (for example, β _L = 0.5) of the second internal coefficient β and an upper limit value β _U (for example, β _U = 1) of the second internal coefficient β. second switching signal generator 64, a second low-pass filter 66 to perform low-pass filtering on the signal beta ₀ to the second switching signal generating unit 64 generates to generate a raw signal beta ₀ either the And.

The first switching signal generator 63 outputs a signal α ₀ (α _L or α _U ) based on the estimated rotational speed ω ^. The signal α ₀ is subjected to filter processing by the first low-pass filter 65, whereby a first internal division coefficient α is generated. Similarly, the second switching signal generator 64 generates a signal β ₀ (β _L or β _U ) according to the estimated rotational speed ω ^ obtained by the rotational speed estimator 22. The signal β ₀ is filtered by the second low-pass filter 66 to generate the second internal division coefficient β. However, a relationship of α <β is established for an arbitrary estimated rotational speed ω ^.

The cutoff frequency ω _c1 of the first low-pass filter 65 is determined to be α = α _L when ω ^ = ω _TL and α = α _U when ω ^ = ω _THE . Similarly, the cutoff frequency ω _c2 of the second low-pass filter 66 is determined so that β = β _L when ω ^ = ω _TLE and β = β _U when ω ^ = ω _TH .
With such a configuration, it is possible to generate the first and second internal coefficients α and β that change so as to increase as the estimated rotational speed ω ^ increases.

In addition, since the original signals α ₀ and β ₀ generated by the switching signal generators 63 and 64 are filtered by the low-pass filters 65 and 66, the first and second internal division coefficients α and β are generated. The dependence of the first and second internal division coefficients α and β on the estimated rotational speed ω ^ is kept low. Therefore, even if the estimated rotational speed ω ^ obtained by the rotational speed estimation unit 22 is unstable due to noise included in the current signal or voltage signal, the first and second that are valid. The internal division coefficients α and β can be generated, and as a result, the internal division processing in the internal division processing unit 43 can be appropriately performed.

  As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form. For example, the configuration of the low-speed range position estimation unit 41 may be the configuration shown in FIG. In this example, the output signal of the high frequency response extracting unit 38 is further filtered by the filter 40 and then input to the rotor position estimating unit 39. The filter 40 is a filter having a pass band around twice the high frequency voltage applied by the high frequency voltage generator 23. As understood from FIG. 3 described above, the response current waveform with respect to the high frequency rotation voltage has peaks corresponding to the N pole and S pole of the rotor, and therefore has a frequency almost twice that of the high frequency rotation voltage. Therefore, a signal having a required frequency can be amplified and detected by applying a filter having a gain that is twice as large as the frequency of the high-frequency rotation voltage to the detection current.

In the embodiments described above, the threshold omega _THE transitioning from a low speed → fast switching region II to the high-speed range III, become divided estimated rotational position theta ^ _M and fast estimated rotational position theta ^ _H and discontinuous, also In the threshold value ω _TLE for transition from the high-speed to low-speed switching region IV to the low-speed region I, the internal division processing unit 43 so that the internal estimated rotational position θ ^ _M and the low-speed estimated rotational position θ ^ _L are discontinuous. Internal processing is performed at However, if the low speed range position estimation unit 41 and the high speed range position estimation unit 42 have a wide speed range with sufficient position estimation accuracy, and therefore the medium speed range can be sufficiently wide, the threshold ω _THE in or perform internal division processing unit as internal division and the estimated rotational position theta ^ _M and fast estimated rotational position theta ^ _H is continuous, the threshold ω divided estimated rotational position theta in _TLE ^ _M and low speed estimated rotational position theta ^ Internal division processing may be performed so that _L is continuous.

In the configuration of FIG. 10 described above, the cutoff frequencies ω _c1 and ω _c2 of the low-pass filters 65 and 66 may be variably set according to the estimated rotational speed ω ^ obtained by the rotational speed estimating unit 22. That is, during high-speed rotation, the cutoff frequencies ω _c1 and ω _c2 may be set to high frequencies so that the low-speed estimated rotational position θ ^ _L is quickly changed to the high-speed estimated rotational position θ ^ _H. On the other hand, during low-speed rotation, the cut-off frequencies ω _c1 and ω _c2 are set to the low-frequency side so that the transition from the high-speed estimated rotation position θ ^ _H to the low-speed estimated rotation position θ ^ _L occurs slowly. Also good.

  Further, the frequency of the high frequency voltage generated by the high frequency voltage generator 23 is set to an audible frequency in order to suppress or prevent the steering mechanism 2 from generating vibrations and abnormal noise due to the superposition of the high frequency voltage on the motor drive signal. You may make it set out of a band. For example, in order to superimpose a high-frequency voltage having a frequency higher than the audible frequency band on the motor drive signal, an exploration high-frequency generation circuit 70 is provided as shown by a two-dot chain line in FIG. It is preferable to superimpose a high frequency voltage on the motor drive signal in the power supply line between them. As a result, a high-frequency voltage outside the audible frequency band can be superimposed on the motor drive signal as a search voltage without being restricted by the PWM frequency in the drive circuit 8.

The search high-frequency voltage is superimposed on the three-phase command voltage V _UVW in the above-described embodiment, but may be configured to be superimposed on the command voltage V _γδ generated by the command voltage generation unit 13.
Furthermore, in the above-described embodiment, a configuration in which a high-frequency exploration voltage is applied as the low-speed region position estimation unit 41 to extract the response of the motor current is employed, and a disturbance observer is used as the high-speed region position estimation unit 42. Although a configuration for estimating the induced voltage is employed, one or both of these may be replaced with a simple sensor.

Furthermore, in the above-described embodiment, the case where the present invention is applied to control the electric motor 3 as a drive source of the electric power steering apparatus has been described. However, the present invention is applicable to applications other than the electric power steering apparatus. It can also be applied to motor control.
In addition, various design changes can be made within the scope of matters described in the claims.

1 is a block diagram for explaining an electrical configuration of an electric power steering apparatus to which a motor control device according to an embodiment of the present invention is applied. FIG. It is a figure for demonstrating rotation of a high frequency voltage vector and an electric current vector. It is a figure for demonstrating the rotor phase angle estimation operation | movement by application of a high frequency voltage vector. It is a block diagram for demonstrating the structural example of the position estimation part for low speed areas. It is a block diagram which shows the structural example of the position estimation part for high speed areas. It is a block diagram for demonstrating an example of a disturbance observer and the structure relevant to this. It is a control area figure for demonstrating the process by an internal division process part and a switching part. It is a figure for demonstrating the function of a correction value calculating part and an addition part. It is a flowchart for demonstrating the flow of a rotor rotational position estimation calculation. It is a block diagram for demonstrating the structural example of an internal division coefficient calculating part. It is a block diagram for demonstrating the other structural example of the position estimation part for low speed areas.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 5 ... Motor control apparatus, 7 ... Microcomputer, 9 ... Current sensor, 19 ... Deviation calculation part, 21 ... Position estimation part

Claims (6)

Designed to be adapted to a state in which the motor is rotating in a predetermined low speed range, position detecting means for low speed range to obtain the rotational position of the motor,
Designed so as to be adapted to a state in which the motor is rotating in a predetermined high speed range that is higher than the low speed range, and a position detection means for high speed range for obtaining the rotational position of the motor;
Rotational speed calculating means for calculating the rotational speed of the motor from the rotational position of the motor obtained by the low speed range position detecting means and the high speed range position detecting means;
Rotational position estimation for estimating the rotational position of the motor based on the rotational position of the motor respectively obtained by the low speed range position detecting means and the high speed range position detecting means and the rotational speed calculated by the rotational speed calculating means. and it means only including,
The rotational position estimating means includes a low speed rotational position determined by the low speed range position detecting means and a high speed rotational position determined by the high speed range position detecting means in a medium speed range between the low speed range and the high speed range. The internal dividing means for dividing the internal speed according to the rotational speed obtained by the rotational speed calculating means to obtain the internal rotational position, and the first predetermined speed in the vicinity of the boundary between the medium speed range and the high speed range. The internal dividing position obtained by the means and the high speed rotational position obtained by the high speed range position detecting means are discontinuously switched, and at a second predetermined speed near the boundary between the low speed range and the medium speed range, the internal dividing means Switching means for discontinuously switching the obtained internal rotation position and the low speed rotation position obtained by the low speed position detecting means and outputting the selected rotational position as a selected rotational position, and correcting the selected rotational position output by the switching means and gradually Change to And a correction means for outputting a constant rotational position,
The correction means corrects the selected rotational position with a correction value obtained so as to converge to zero over time, with an error between the internal rotation position and the high speed rotation position or the low speed rotation position as an initial correction value. , Motor control device. A motor current detecting means for detecting a motor current flowing through the motor;
The motor control device according to claim 1, wherein the low speed range position detection unit includes a low speed range position estimation unit that estimates a rotational position of the motor based on a motor current detected by the motor current detection unit. Motor current detecting means for detecting a motor current flowing through the motor;
Motor voltage indicating means for indicating a motor voltage applied to the motor,
The high speed range position detecting means includes a high speed range position estimating means for estimating the rotational position of the motor based on the motor current detected by the motor current detecting means and the motor voltage indicated by the motor voltage indicating means. The motor control device according to claim 1 or 2.   The correction means is
  When the switching means switches the selected rotation position from the internal rotation position to the high-speed rotation position, an error between the internal rotation position and the high-speed rotation position is used as the initial correction value, and the switching means is the selected rotation position. When the position is switched from the internal rotation position to the low-speed rotation position, the error between the internal rotation position and the low-speed rotation position is set as the initial correction value, and converges to zero with the passage of time from the switching of the selected rotation position. Correction value calculating means for obtaining a correction value so as to
  Adding means for adding the correction value calculated by the correction value calculating means to the selected rotational position output by the switching means;
The motor control apparatus as described in any one of Claims 1-3 containing these.   A first control area transition from a control area where the internal rotation position is the selected rotation position to a control area where the high speed rotation position is the selected rotation position, or the internal rotation position is the selected rotation position. Control region transition determining means for determining whether or not a second control region transition from the control region to the control region in which the low-speed rotational position is the selected rotational position has occurred, the first control region transition or the first control region And an initial correction value updating unit that updates the initial correction value when two control region transitions occur and does not update the initial correction value if the first control region transition or the second control region transition does not occur. The motor control apparatus as described in any one of Claims 1-4.   The internal dividing means includes
  In the control region where the motor accelerates from the low speed region toward the high speed region, the high speed rotational position θ ^ _H , The low-speed rotation position θ ^ _L , And the high-speed rotation position θ ^ _H Using the first internal division coefficient α (where 0 ≦ α) representing the usage rate, the internal rotation position θ ^ _M With the formula θ ^ _M = (1-α) θ ^ _L ・ + Α ・ θ ^ _H Sought by,
  In the control region where the motor decelerates from the high speed region toward the low speed region, the high speed rotational position θ ^ _H , The low-speed rotation position θ ^ _L , And the high-speed rotation position θ ^ _H Using the second internal division coefficient β (where α <β ≤ 1) representing the usage rate of the internal rotation position θ ^ _M With the formula θ ^ _M = (1-β) θ ^ _L ・ + Β ・ θ ^ _H Asking for,
The motor control apparatus as described in any one of Claims 1-5.

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