JP5505682B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device for driving a brushless motor. The brushless motor can be used, for example, as a drive source for a vehicle steering apparatus. An example of a vehicle steering device is an electric power steering device.

  A motor control device for driving and controlling a brushless motor is generally configured to control the supply of motor current in accordance with the output of a rotation angle sensor for detecting the rotation angle of the rotor. As the rotation angle sensor, a resolver that outputs a sine wave signal and a cosine wave signal corresponding to the rotor rotation angle (electrical angle) is generally used. However, the resolver is expensive, has a large number of wires, and has a large installation space. Therefore, there exists a subject that the cost reduction and size reduction of an apparatus provided with the brushless motor are inhibited.

Therefore, a sensorless driving method for driving a brushless motor without using a rotation angle 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, a sensing signal is injected into the stator, and a motor response to the sensing signal is detected. Based on this motor response, the rotor rotational position is estimated.
JP 2007-267549 Gazette

  The above sensorless driving method estimates the rotational position of the rotor using an induced voltage or a sensing signal, and controls the motor based on the rotational position obtained by the estimation. However, this drive system is not suitable for any application. For example, this drive system is used to control a brushless motor used as a drive source of an electric power steering device that applies a steering assist force to a steering mechanism of a vehicle. The method has not been established yet. Therefore, realization of sensorless control by another method is desired.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control apparatus that can control a motor by a new control method that does not use a rotation angle sensor.

In order to achieve the above object, the invention according to claim 1 is directed to a motor (3) including a rotor (50) and a stator (55) opposed to the rotor for detecting a rotation angle of the rotor. And a command torque setting means (21) for setting command torque to be applied to the drive target of the motor , and a motor control device for controlling without using the detection value of the rotation angle sensor. Torque detection means (1) for detecting torque, and current drive means (31-31) for driving the motor with an axis current value (I _γ ^* ) of a rotating coordinate system according to a control angle (θ _C ) that is a control rotation angle. 36), wherein in accordance with the deviation between the torque detected by said torque detecting means and the command torque set by the command torque setting unit, an addition angle calculation unit that calculates the addition angle to be added to the control angle (22 And 23), the predetermined calculation cycles, the control angle calculation means for calculating a current value of the control angle by adding the addition angle that is calculated by the addition angle calculation unit to the immediately preceding value of the control angle a (alpha) (26) And monitoring means (25, S11, S12) for monitoring the state of the addition angle and determining an abnormality when the number of times the absolute value of the addition angle is equal to or greater than a predetermined threshold continues for a predetermined number of times; the includes an abnormality between the control angle correction unit that corrects the control angle when it is determined (27, 29), wherein the control angle correction unit (29), for a plurality of the control angle, set by the command torque setting unit Between the commanded torque and the detected torque detected by the torque detecting means (S23, S24) and the difference between the sampled commanded torque and the detected torque among the plurality of control angles Select the control angle having the smallest and a control angle selecting means for setting as a new control angle (S26), a motor control device. The alphanumeric characters in parentheses indicate corresponding components in the embodiments described later. The same applies hereinafter.
According to a second aspect of the present invention, there is provided a motor (3) including a rotor (50) and a stator (55) opposed to the rotor, the rotation angle sensor for detecting the rotation angle of the rotor. A motor control device for controlling without using a detected value, which is a command torque setting means (21) for setting a command torque to be applied to a drive target of the motor, and a torque for detecting a torque acting on the drive target and detection means (1), a control angle that is a rotational angle used in a control axis current value of the rotating coordinate system that rotates in accordance with ^{_{(θ C) (I γ *}} ) in the current driving means for driving the motor (31 to 36), wherein An addition angle calculation means (22, 23) for calculating an addition angle to be added to the control angle in accordance with a deviation between the instruction torque set by the instruction torque setting means and the torque detected by the torque detection means; Predetermined Every calculation cycle, the control angle calculation means for calculating a current value of the control angle by adding the addition angle that is calculated by the addition angle calculation unit to the previous value (alpha) of the control angle (26), the addition angle Monitoring means (25, S11, S12) for monitoring the state and determining an abnormality when the number of times the absolute value of the addition angle is equal to or greater than a predetermined threshold continues for a predetermined number of times; and the absolute value of the addition angle Addition angle limiting means (24) for limiting the value based on a predetermined limit value (predetermined value), and limit value changing means for changing the limit value (changing from the default value) when the abnormality is determined (30).

According to these inventions, an axial current value (hereinafter referred to as “virtual axis”), which is a rotational coordinate system according to a control angle (γδ coordinate system; hereinafter referred to as “virtual rotational coordinate system”). While the motor is driven by the “virtual axis current value”), the control angle is updated by adding the addition angle every calculation cycle. Thus, the necessary torque can be generated by driving the motor with the virtual axis current value while updating the control angle, that is, while updating the coordinate axis (virtual axis) of the virtual rotation coordinate system. Thus, an appropriate torque can be generated from the motor without using a rotation angle sensor. The addition angle is calculated in accordance with the deviation between the command torque and the detected torque, the motor ing and values corresponding to the response of the motor for the torque or the imaginary axis current value to be generated.

Further, in the first and second aspects of the invention, the state of the addition angle is monitored by the monitoring means. Therefore, based on the monitoring result, it can be determined whether there is an abnormality in control. Specifically, when the absolute value of the addition angle is continuously equal to or greater than a predetermined threshold value for a predetermined number of times, it is determined as abnormal. When the state where the absolute value of the addition angle is large continues for a long time, the state where the fluctuation of the control angle is large continues and the control angle cannot be converged to the appropriate value. I can judge.

The predetermined number of times may be determined according to the longest time (the longest time assumed in a normal state) that the absolute value of the addition angle may continue at the threshold value or more and the calculation cycle.
After all, the function of the monitoring means is that the control angle continues to fluctuate for a certain time with a fluctuation width equal to or greater than the threshold, in other words, the control angle fluctuates for a certain angle with a fluctuation width greater than the threshold. This is a function to judge that an abnormality occurs when a state of continuing to occur occurs.

Furthermore, in the invention of claim 1 , the control angle is corrected when an abnormality occurs. For example, when the addition angle takes a constant value (the absolute value is a value equal to or greater than the threshold value), the control angle may cyclically take a finite number of values. In such a situation, there is a possibility that the state in which the control angle changes by jumping over the appropriate value according to the required torque may continue, and therefore the control angle may not be able to be a value close to the appropriate value. . Therefore, in the present invention, when an abnormality occurs, the control angle is corrected and the control angle is forcibly shifted. As a result, the possibility that the control angle takes a value close to an appropriate value is increased, and accordingly, the control angle is easily converged to an appropriate value corresponding to the required torque. In this way, it can be urged to get out of the abnormal state.

According to the first aspect of the present invention, when it is determined that there is an abnormality, the command torque and the detected torque are sampled for a plurality of control angles. Then, the control angle that minimizes the difference between the command torque and the detected torque is selected as a new control angle. As a result, the control angle can be set to a value approximate to an appropriate value that can bring the detected torque close to the command torque, and thus the convergence of the control angle to the appropriate value can be promoted.

On the other hand, according to the second aspect of the present invention, by adding an appropriate restriction to the addition angle, it is possible to suppress an excessive addition angle from being added to the control angle compared to the actual rotation of the rotor. More specifically, the motor can be controlled more appropriately by adding a restriction so that the addition angle is set within a reasonable range with respect to the rotational speed range of the rotor. On the other hand, when it is determined as abnormal, the limit value is changed from a predetermined limit value (default value). If the addition angle is limited by a certain limit value, there is a possibility that the control angle may cyclically take a finite number of values, which may make it difficult to converge the control angle to an appropriate value. Therefore, when the abnormality occurs, the limit value is changed from the default value, and the convergence of the control angle to an appropriate value can be promoted.

The predetermined limit value (predetermined value) may be a value determined by the following equation, for example. However, the “maximum rotor angular velocity” in the following equation is the maximum value of the rotor angular velocity in electrical angle.
Predetermined limit value (predetermined value) = maximum rotor angular velocity × computation cycle For example, when the rotation of the motor is transmitted to the steering shaft of the vehicle steering device via a reduction mechanism with a predetermined reduction ratio, the maximum rotor angular velocity Is given by the maximum steering angular velocity (maximum rotational angular velocity of the steering shaft) × reduction ratio × the number of pole pairs. The “number of pole pairs” is the number of magnetic pole pairs (pairs of N poles and S poles) that the rotor has.

The invention according to claim 3 is the motor control device according to claim 2 , wherein the changed limit value is a value that is not a divisor of 360 degrees. According to this configuration, the changed limit value is not a divisor of 360 degrees. For this reason, even if the absolute value of the addition angle is limited to the changed limit value, the control angle does not cyclically take a limited number of decimal values. Thereby, the possibility that the control angle approaches the appropriate value can be increased, and the convergence of the control angle to the appropriate value can be promoted.

The invention according to claim 4 is the motor control device according to claim 2 , wherein the changed limit value is smaller than the predetermined limit value (predetermined value). According to this configuration, when it is determined that there is an abnormality, the possibility that the control angle approaches the appropriate value is increased by setting the limit value to a value smaller than the predetermined limit value (predetermined value). . Thereby, convergence of the control angle to an appropriate value can be promoted.

The motor may provide a driving force to the steering mechanism (2) of the vehicle. In this case, the torque detection means detects a steering torque applied to the operation member (10) operated for steering the vehicle , and the instruction torque setting means sets the instruction steering torque. is preferably a command steering torque setting means for.

  According to this configuration, the command steering torque is set, and the addition angle is calculated according to the deviation between the command steering torque and the steering torque (detected value). Thus, the addition angle is determined so that the steering torque becomes the command steering torque, and the control angle corresponding to the addition angle is determined. Therefore, by appropriately determining the instruction steering torque, it is possible to generate an appropriate driving force from the motor and apply it to the steering mechanism. That is, the deviation (load angle) between the coordinate axis of the rotating coordinate system (dq coordinate system) and the virtual axis according to the magnetic pole direction of the rotor is led to a value corresponding to the command steering torque. As a result, an appropriate torque is generated from the motor, and a driving force according to the driver's steering intention can be applied to the steering mechanism.

  In a vehicle steering device (for example, an electric power steering device) in which an operation member and a steering mechanism are mechanically coupled, the motor response (torque generated by the motor) to the virtual axis current value is the change in the detected steering torque. It appears. Therefore, in such a vehicle steering apparatus, it can be said that calculating the addition angle in accordance with the detected steering torque calculates the addition angle in accordance with the motor response to the virtual axis current value.

  The motor control device further includes a steering angle detection means (4) for detecting a steering angle of the operation member, and the instruction steering torque setting means indicates instruction steering according to a steering angle detected by the steering angle detection means. The torque is preferably set. According to this configuration, since the instruction steering torque is set according to the steering angle of the operation member, an appropriate torque according to the steering angle can be generated from the motor, and the steering torque applied to the operation member by the driver can be increased. The value can be derived according to the steering angle. Thereby, a favorable steering feeling can be obtained.

  The command steering torque setting unit may set the command steering torque according to the vehicle speed detected by the vehicle speed detection unit (6) that detects the vehicle speed of the vehicle. According to this configuration, since the command steering torque is set according to the vehicle speed, so-called vehicle speed sensitive control can be performed. As a result, a good steering feeling can be realized. For example, an excellent steering feeling can be obtained by setting the command steering torque to be smaller as the vehicle speed is higher, that is, at higher speeds.

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 device (an example of a vehicle steering device) to which a motor control device according to a reference embodiment is applied. This electric power steering apparatus includes a torque sensor 1 for detecting a steering torque T applied to a steering wheel 10 as an operation member for steering the vehicle, and a steering assist force via a speed reduction mechanism 7 to the steering mechanism 2 of the vehicle. The motor 3 (brushless motor) that gives the power, the steering angle sensor 4 that detects the steering angle that is the rotation angle of the steering wheel 10, the motor control device 5 that drives and controls the motor 3, and the electric power steering device are mounted. And a vehicle speed sensor 6 for detecting the speed of the vehicle.

The motor control device 5 drives the motor 3 according to the steering torque detected by the torque sensor 1, the steering angle detected by the steering angle sensor 4, and the vehicle speed detected by the vehicle speed sensor 6, thereby responding to the steering situation and the vehicle speed. Realize appropriate steering assistance.
In this reference embodiment, the motor 3 is a three-phase brushless motor. As illustrated schematically in FIG. 2, the motor 3 is a U-phase, V-phase disposed in a rotor 50 as a field and a stator 55 facing the rotor 50. Phase and W phase stator windings 51, 52, 53. The motor 3 may be of an inner rotor type in which a stator is disposed facing the outside of the rotor, or may be of an outer rotor type in which a stator is disposed facing the inside of a cylindrical rotor.

Three-phase fixed coordinates (UVW coordinate system) are defined in which the U, V, and W axes are taken in the direction of the stator windings 51, 52, and 53 of each phase. Also, a two-phase rotational coordinate system (dq coordinate system) in which the d axis (magnetic pole axis) is taken in the magnetic pole direction of the rotor 50 and the q axis (torque axis) is taken in the direction perpendicular to the d axis in the rotation plane of the rotor 50. The actual rotating coordinate system) is defined. The dq coordinate system is a rotating coordinate system that rotates with the rotor 50. In the dq coordinate system, since only the q-axis current contributes to the torque generation of the rotor 50, the d-axis current may be set to zero and the q-axis current may be controlled according to the desired torque. The rotation angle (rotor angle) θ _M of the rotor 50 is the rotation angle of the d axis with respect to the U axis. The dq coordinate system is an actual rotating coordinate system according to the rotor angle θ _M. By using this rotor angle θ _M , coordinate conversion between the UVW coordinate system and the dq coordinate system can be performed.

On the other hand, in this reference embodiment, a control angle θ _C representing a control rotation angle is introduced. The control angle θ _C is a virtual rotation angle with respect to the U axis. A virtual two-phase rotating coordinate system (γδ coordinate system, virtual rotating coordinate system) is defined with a virtual axis corresponding to the control angle θ _C as a γ axis and an axis advanced by 90 ° with respect to the γ axis as a δ axis. Define. When the control angle θ _C is equal to the rotor angle θ _M , the γδ coordinate system that is the virtual rotation coordinate system and the dq coordinate system that is the actual rotation coordinate system coincide. That is, the γ-axis as the virtual axis matches the d-axis as the real axis, and the δ-axis as the virtual axis matches the q-axis as the real axis. The γδ coordinate system is a virtual rotating coordinate system according to the control angle θ _C. Coordinate conversion between the UVW coordinate system and the γδ coordinate system can be performed using the control angle θ _C.

The difference between the control angle θ _C and the rotor angle θ _M is defined as the load angle θ _L (= θ _C −θ _M ).
When the γ-axis current I _γ is supplied to the motor 3 according to the control angle θ _C, the q-axis component of the γ-axis current I _γ (orthographic projection on the q-axis) contributes to the torque generation of the rotor 50 and the q-axis current I _q Become. That is, the relationship of the following formula (1) is established between the γ-axis current I _γ and the q-axis current I _q .
I _q = I _γ · sinθ _L (1)
Refer to FIG. 1 again. The motor control device 5 detects a current flowing in a microcomputer 11, a drive circuit (inverter circuit) 12 that is controlled by the microcomputer 11 and supplies electric power to the motor 3, and a stator winding of each phase of the motor 3. And a current detection unit 13.

The current detection unit 13 uses phase currents I _U , I _V , I _W (hereinafter, collectively referred to as “three-phase detection current I _UVW ”) flowing through the stator windings 51, 52, 53 of each phase of the motor 3. To detect. These are current values in the coordinate axis directions in the UVW coordinate system.
The microcomputer 11 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 command steering torque setting unit 21, a torque deviation calculation unit 22, a PI (proportional integration) control unit 23, a limiter 24, an addition angle monitoring unit 25, and a control angle calculation unit 26. A control angle correction unit 27, a command current value generation unit 31, a current deviation calculation unit 32, a PI control unit 33, a γδ / UVW conversion unit 34, a PWM (Pulse Width Modulation) control unit 35, a UVW / Γδ converter 36 is included.

The command steering torque setting unit 21 sets the command steering torque T ^* based on the steering angle detected by the steering angle sensor 4 and the vehicle speed detected by the vehicle speed sensor 6. For example, as shown in FIG. 4, for example, when the steering angle is a positive value (a state of steering to the right), the command steering torque T ^* is set to a positive value (torque to the right), and the steering angle is The instruction steering torque T ^* is set to a negative value (torque to the left) when the value is negative (steering to the left). Then, the command steering torque T ^* is set so that the absolute value of the steering angle increases as the absolute value of the steering angle increases (in the example of FIG. 4, the absolute value increases nonlinearly). However, the command steering torque T ^* is set within a predetermined upper limit value (positive value, for example, +6 Nm) and lower limit value (negative value, for example, −6 Nm). Further, the command steering torque T ^* is set such that the absolute value thereof decreases as the vehicle speed increases. That is, vehicle speed sensitive control is performed.

The torque deviation calculation unit 22 includes a command steering torque T ^* set by the command steering torque setting unit 21 and a steering torque T detected by the torque sensor 1 (hereinafter referred to as “detected steering torque T” for distinction). Deviation (torque deviation) ΔT. The PI control unit 23 performs a PI calculation on the torque deviation ΔT. That is, the torque deviation calculation unit 22 and the PI control unit 23 constitute torque feedback control means for guiding the detected steering torque T to the command steering torque T ^* . The PI control unit 23 calculates the addition angle α for the control angle θ _C by performing PI calculation for the torque deviation ΔT.

The limiter 24 is a limiting unit that limits the addition angle α obtained by the PI control unit 23. More specifically, the limiter 24 limits the addition angle α to a value between a predetermined upper limit value UL (positive value) and a lower limit value LL (negative value). The upper limit value UL and the lower limit value LL are determined based on a predetermined limit value ω _max (ω _max > 0, for example, ω _max = 45 degrees). The predetermined limit value ω _max is determined based on, for example, the maximum steering angular velocity. The maximum steering angular velocity is a maximum value that can be assumed as the steering angular velocity of the steering wheel 10 and is, for example, about 800 deg / sec.

The change speed of the electrical angle of the rotor 50 at the maximum steering angular speed (the angular speed at the electrical angle. The maximum rotor angular speed) is the maximum steering angular speed, the reduction ratio of the speed reduction mechanism 7, and the rotor 50 as shown in the following equation (2). Given by the product of the number of pole pairs. The number of pole pairs is the number of magnetic pole pairs (pairs of N poles and S poles) that the rotor 50 has.
Maximum rotor angular speed = Maximum steering angular speed x Reduction ratio x Number of pole pairs (2)
The maximum value of the electrical angle change amount of the rotor 50 (the maximum value of the rotor angle change amount) during the calculation (control cycle) of the control angle θ _C is the value obtained by multiplying the maximum rotor angular velocity by the calculation cycle as shown in the following equation (3). It becomes.

Maximum value of rotor angle change = Maximum rotor angular speed x Calculation cycle
= Maximum steering angular velocity x reduction ratio x number of pole pairs x calculation cycle (3)
The maximum value of the rotor angle change amount is the maximum change amount of the control angle θ _C allowed during one calculation cycle. Therefore, the maximum value of the rotor angle change may be set to the limit value ω _max (> 0). Using the limit value ω _max , the upper limit value UL and the lower limit value LL of the addition angle α can be expressed by the following equations (4) and (5), respectively.

UL = + ω _max (4)
LL = −ω _max (5)
The addition angle α after the limit processing by the limiter 24 is added to the previous value θ _C (n−1) (n is the number of the current calculation cycle) of the control angle θ _C in the adder 26A of the control angle calculation unit 26. (Z ^-1 represents the previous value of the signal). However, the initial value of the control angle θ _C is a predetermined value (eg, zero).

The control angle calculation unit 26 includes an adder 26A that adds the addition angle α given from the limiter 24 to the previous value θ _C (n−1) of the control angle θ _C. That is, the control angle calculation unit 26 calculates the control angle θ _C at every predetermined calculation cycle. Then, the control angle θ _C in the previous calculation cycle is set as the previous value θ _C (n−1), and this value is used to obtain the current value θ _C (n) that is the control angle θ _C in the current calculation cycle.
The addition angle monitoring unit 25 compares the absolute value of the addition angle α obtained by the PI control unit 23 with a predetermined threshold value _αth . Then, the addition angle monitoring unit 25 determines that an abnormality has occurred when a state where the absolute value of the addition angle α is equal to or greater than the threshold value α _th continues over a predetermined number of calculation cycles, and the control angle correction unit 27 Notify that an error has occurred. The threshold value α _th may be equal to the predetermined limit value ω _max . In this case, the predetermined number of calculation cycles may be set to a value equal to or greater than an assumed value of the longest steering continuation time at the maximum steering angular velocity. Thus, it can be determined that an abnormality has occurred when the control angle θ _C continues to be limited by the limiter 24 for a longer time than the time assumed as the longest steering continuation time at the maximum steering angular velocity.

When the control angle correction unit 27 receives a notification of the occurrence of an abnormality from the addition angle monitoring unit 25, the control angle θ _C obtained by the control angle calculation unit 26 is set to a predetermined value Δθ (for example, Δθ = 5 degrees to 10 degrees). Perform shift correction. That is, the corrected control angle θ _C is a value obtained by adding the predetermined value Δθ to the uncorrected control angle θ _C. Of course, no problem even using the control angle theta _C corrected by subtracting the correction value Δθ from the control angle theta _C before correction.

The command current value generation unit 31 generates a current value to be passed through the coordinate axis (virtual axis) of the γδ coordinate system, which is a virtual rotation coordinate system corresponding to the control angle θ _C that is a control rotation angle, as the command current value. Is. Specifically, a γ-axis command current value I _γ ^* and a δ-axis command current value I _δ ^* (hereinafter, collectively referred to as “two-phase command current value I _γδ ^* ) are generated. The unit 31 sets the γ-axis command current value I _γ ^* to a significant value and sets the δ-axis command current value I _δ ^* to 0. More specifically, the command current value generation unit 31 includes the torque sensor 1. The γ-axis command current value I _γ ^* is set based on the detected steering torque T detected by the above.

A setting example of the γ-axis command current value I _γ ^* with respect to the detected steering torque T is shown in FIG. A dead zone NR is set in a region where the detected steering torque T is near zero. The γ-axis command current value I _γ ^* rises steeply in a region outside the dead zone NR, and is set to be a substantially constant value above a predetermined torque. Thereby, when the driver is not operating the steering wheel 10, the energization to the motor 3 is stopped, and unnecessary power consumption is suppressed.

The current deviation calculation unit 32 has a deviation I _γ ^* −I _γ of the γ-axis detected current I _γ with respect to the γ-axis command current value I _γ ^* generated by the command current value generation unit 31 and a δ-axis command current value I _δ ^*. The deviation I _δ ^* −I _δ of the δ-axis detection current I _δ with respect to (= 0) is calculated. The γ-axis detection current I _γ and the δ-axis detection current I _δ are supplied from the UVW / γδ conversion unit 36 to the deviation calculation unit 32.

The UVW / γδ conversion unit 36 converts the three-phase detection current I _UVW (U-phase detection current I _U , V-phase detection current I _V and W-phase detection current I _W ) of the UVW coordinate system detected by the current detection unit 13 to γδ. Two-phase detection currents I _γ and I _{δ in the} coordinate system (hereinafter collectively referred to as “two-phase detection currents I _γδ ”). These are supplied to the current deviation calculation unit 32. For the coordinate conversion in the UVW / γδ conversion unit 36, the control angle θ _C calculated by the control angle calculation unit 26 is used.

The PI control unit 33 performs a PI calculation on the current deviation calculated by the current deviation calculation unit 32 to thereby provide a two-phase instruction voltage V _γδ ^* (γ-axis instruction voltage V _γ ^* and δ-axis instruction to be applied to the motor 3. Voltage V _δ ^* ). This two-phase instruction voltage V _γδ ^* is _supplied to the γδ / UVW conversion unit 34.
The γδ / UVW converter 34 generates a three-phase instruction voltage V _UVW ^* by performing a coordinate conversion operation on the two-phase instruction voltage V _γδ ^* . The three-phase command voltage V _UVW ^* includes a U-phase command voltage V _U ^* , a V-phase command voltage V _V ^*, and a W-phase command voltage V _W ^* . The three-phase instruction voltage V _UVW ^* is given to the PWM control unit 35.

The PWM control unit 35 includes a U-phase PWM control signal, a V-phase PWM control signal, and a W-phase PWM having a duty corresponding to the U-phase instruction voltage V _U ^* , the V-phase instruction voltage V _V ^*, and the W-phase instruction voltage V _W ^* , respectively. A control signal is generated and supplied to the drive circuit 12.
The drive circuit 12 includes a three-phase inverter circuit corresponding to the U phase, the V phase, and the W phase. The power elements constituting the inverter circuit are controlled by a PWM control signal supplied from the PWM control unit 35, so that a voltage corresponding to the three-phase instruction voltage V _UVW ^* is a stator winding 51, 52 for each phase of the motor 3. , 53 is applied.

The current deviation calculation unit 32 and the PI control unit 33 constitute a current feedback control unit. By the function of the current feedback control means, the motor current flowing through the motor 3 is controlled so as to approach the two-phase command current value I _γδ ^* set by the command current value generation unit 31.
FIG. 3 is a control block diagram of the electric power steering apparatus. However, in order to simplify the description, the function of the limiter 24 is omitted.

By the PI control (K _P is a proportional coefficient, K _I is an integral coefficient, and 1 / s is an integral operator) with respect to a deviation (torque deviation) between the command steering torque T ^* and the detected steering torque T, the addition angle α is Generated. It is obtained by adding the addition the addition angle alpha control angle theta previous value of _{C θ C (n-1)} , the current value of the control angle _{θ C θ C (n) =} θ C (n-1) + α is Desired. At this time, the deviation between the control angle θ _C and the actual rotor angle θ _M of the rotor 50 is the load angle θ _L = θ _C −θ _M.

Therefore, when the γ-axis current I _γ is supplied according to the γ-axis command current value I _γ ^* to the γ-axis (virtual axis) of the γδ coordinate system (virtual rotation coordinate system) according to the control angle θ _C , the q-axis current I _q = I _γ sinθ _L This q-axis current I _q contributes to the torque generated by the rotor 50. That is, the value obtained by multiplying the torque constant K _T of the motor 3 by the q-axis current I _q (= I _γ sin θ _L ) is used as the assist torque T _A (= K _T · I _γ sin θ _L ) via the speed reduction mechanism 7. And transmitted to the steering mechanism 2. _A value obtained by subtracting the assist torque TA from the load torque _TL from the steering mechanism 2 is the steering torque T that the driver should apply to the steering wheel 10. As the steering torque T is fed back, the system operates so as to guide the steering torque T to the command steering torque T ^* . That is, the addition angle α is obtained so that the detected steering torque T matches the command steering torque T ^* , and the control angle θ _C is controlled accordingly.

In this way, while the current is passed through the γ-axis that is the virtual axis for control, the control angle θ _C is updated with the addition angle α obtained according to the deviation ΔT between the command steering torque T ^* and the detected steering torque T. As a result, the load angle θ _L changes, and a torque corresponding to the load angle θ _L is generated from the motor 3. As a result, a torque corresponding to the command steering torque T ^* set based on the steering angle and the vehicle speed can be generated from the motor 3, so that an appropriate steering assist force corresponding to the steering angle and the vehicle speed can be applied to the steering mechanism 2. Can be given. That is, the steering assist control is executed such that the steering torque increases as the absolute value of the steering angle increases, and the steering torque decreases as the vehicle speed increases.

In this way, an electric power steering apparatus that can appropriately control the motor 3 without using a rotation angle sensor and perform appropriate steering assistance can be realized. Thereby, a structure can be simplified and cost reduction can be aimed at.
FIG. 6 is a flowchart for explaining the operation of the limiter 24. The limiter 24 compares the addition angle α obtained by the PI control unit 23 with the upper limit value UL (step S1), and when the addition angle α exceeds the upper limit value UL (step S1: YES), the upper limit value. UL is substituted for the addition angle α (step S2). Therefore, the upper limit value UL (= + ω _max ) is added to the control angle θ _C.

If the addition angle α obtained by the PI control unit 23 is equal to or smaller than the upper limit value UL (step S1: NO), the limiter 24 further compares the addition angle α with the lower limit value LL (step S3). If the addition angle α is less than the lower limit value (step S3: YES), the lower limit value LL is substituted for the addition angle α (step S4). Therefore, the lower limit LL (= −ω _max ) is added to the control angle θ _C.

If the addition angle α obtained by the PI control unit 23 is not less than the lower limit value LL and not more than the upper limit value UL (step S3: NO), the addition angle α is used for addition to the control angle θ _{C as} it is.
In this way, the addition angle α can be limited between the upper limit value UL and the lower limit value LL, so that the control can be stabilized. More specifically, even if a control unstable state (a state where the assist force is unstable) occurs when the current is insufficient or the control is started, the transition from this state to the stable control state can be promoted.

FIG. 7 is a flowchart for explaining processing by the addition angle monitoring unit 25 and the control angle correction unit 27. The addition angle monitoring unit 25 compares the absolute value of the addition angle α obtained by the PI control unit 23 with the threshold value α _th (step S11). When the absolute value of the addition angle α is equal to or greater than the threshold value α _th (step S11: YES), the addition angle monitoring unit 25 further continues the state of | α | ≧ α _{th for} a predetermined number of calculation cycles. It is determined whether or not (step S12). If this determination is affirmed, it is determined that an abnormality has occurred, and the addition angle monitoring unit 25 notifies the control angle correction unit 27 of the occurrence of the abnormality (step S13). In response to this, the control angle correction unit 27 performs correction by adding (or subtracting) a predetermined value Δθ to the control angle θ _C in the control angle calculation unit 26 (step S14). If the determination in step S11 or step S12 is negative, the control angle θ _C is not corrected.

The threshold α _th is preferably set to a value equal to or less than the predetermined limit value ω _max , and may be set to a value equal to the limit value ω _max , for example.
The state where the absolute value of the addition angle α is equal to or greater than the threshold value α _th is continued when the state where the addition angle α is subjected to the restriction process by the limiter 24 is continued. In this case, since the control angle θ _C changes by the limit value ω _max every calculation cycle, the amount of change is large. In addition, since the control angle θ _C changes by a certain limit value ω _max , the control angle θ _C is in a state of taking a finite number of values cyclically. In particular, when the limit value ω _max is a divisor of 360 degrees (for example, 45 degrees), the control angle θ _C cyclically takes a small number of values. In such a state, the control angle θ _C may not be able to take a value close to an appropriate value for bringing the detected steering torque T close to the command steering torque T ^* . That is, the control angle θ _C continues to fluctuate beyond the appropriate value.

Therefore, in this reference embodiment, when the state where the absolute value of the addition angle α is equal to or greater than the threshold value α _th continues, it is determined that the abnormal state as described above has occurred, and the control angle θ _C is set to a predetermined value. The value Δθ is forcibly shifted. As a result, it is possible to increase the possibility that the control angle θ _C takes a value in the vicinity of the appropriate value. As a result, the control angle θ _C can be converged to the appropriate value by removing the abnormal state as described above. it can. Thus, the steering assist force can be quickly released from the unstable state, so that the steering feeling can be improved.

FIG. 8 is a block diagram for explaining the configuration of an electric power steering apparatus according to another embodiment of the present invention. In FIG. 8, the corresponding parts of the respective parts shown in FIG.
In this reference embodiment, a gain changing unit 28 that changes the gain of the PI control unit 23 is provided. The addition angle monitoring unit 25 notifies the gain change unit 28 of the occurrence of an abnormality when the state where the absolute value of the addition angle α is equal to or greater than the threshold value α _th continues for a predetermined number of calculation cycles. In response to this notification, the gain changing unit 28 corrects the gain of the PI control unit 23 to decrease.

The PI control unit 23 includes a proportional element 23a, an integral element 23b, and an adder 23c. However, K _P is a proportional gain, K _I is an integral gain, 1 / s is an integration operator. The addition angle α is obtained by adding the calculation results of the proportional element 23a and the integral element 23b by the adder 23c. The gain change unit 28, when required, the gain (proportional gain) K _P of the proportional element 23a, corrected to decrease the gain (integral gain) K _I of the integral element 23b.

FIG. 9 is a flowchart for explaining processing by the addition angle monitoring unit 25 and the gain changing unit 28. In FIG. 9, steps corresponding to the respective steps shown in FIG. 7 are given the same reference numerals.
The addition angle monitoring unit 25 compares the absolute value of the addition angle α obtained by the PI control unit 23 with the threshold value α _th (step S11). When the absolute value of the addition angle α is equal to or greater than the threshold value α _th (step S11: YES), the addition angle monitoring unit 25 further continues the state of | α | ≧ α _{th for} a predetermined number of calculation cycles. It is determined whether or not (step S12). If this determination is affirmed, it is determined that an abnormality has occurred, and the addition angle monitoring unit 25 notifies the gain changing unit 28 of the occurrence of the abnormality (step S13). In response to this, the gain changing unit 28 reduces and corrects the gain for calculating the addition angle α, that is, the gain (proportional gain and integral gain) of the PI control unit 23 (step S15). If the determination in step S11 or step S12 is negative, the gain of the PI control unit 23 is not corrected.

When the gain of the PI control unit 23 is corrected to decrease, the absolute value of the addition angle α calculated by the PI control unit 23 becomes small. As a result, it is possible to escape from the abnormal state in which the addition angle α is continuously limited by the limiter 24, and the control angle θ _C changes with an amount of change smaller than the limit value ω _max . As a result, the control angle θ _C can be changed in small increments, so that convergence to an appropriate value can be promoted.

In addition, it can replace with PI control part 23 and can also be set as the structure which calculates | requires addition angle (alpha) using a PID (proportional / integral / differential) calculating part. Even in this case, the gain reduction correction when an abnormality occurs may be performed for the proportional gain and the integral gain.
FIG. 10 is a block diagram for explaining the configuration of the electric power steering apparatus according to the first embodiment of the present invention. In FIG. 10, the same reference numerals are given to the corresponding parts of the respective parts shown in FIG.

In this embodiment, when the addition angle monitoring unit 25 notifies the occurrence of an abnormality, a control angle selection unit 29 is provided that receives this and sets a new control angle θ _C for the control angle calculation unit 26. . More specifically, when receiving the notification of occurrence of abnormality, the control angle selection unit 29 samples the command steering torque T ^* , the detected steering torque T, and the control angle θ _C every calculation cycle. Based on the sampling result, the control angle selection unit 29 selects the control angle θ _C that minimizes the difference between the command steering torque T ^* and the detected steering torque T (that is, the torque deviation ΔT), and calculates the control angle. A new control angle θ _C is set in the unit 26.

FIG. 11 is a flowchart for explaining processing by the control angle selection unit 29. When the notification of the occurrence of abnormality is received from the addition angle monitoring unit 25 (step S21: YES), the control angle selection unit 29 updates the values θ ₁ , θ ₂ , θ of the control angle θ _C that are updated and set for each calculation cycle. _3, ......, theta _m sampled (step S22), and further, in the calculation cycle corresponding to the value of the control angle theta _C, the command steering torque T ^* values T ^* _1, T ^* _2, T ^* _3, ... ..., T ^* value T ₁ of the _m and the detected steering torque _{T, T 2, T 3,} ......, respectively sample the T _m (step S23, S24). The sampling of the control angle θ _C , the command steering torque T ^*, and the detected steering torque T is performed, for example, until the control angle θ _C changes over a range of 360 degrees. When the addition angle monitoring unit 25 notifies the occurrence of an abnormality, the control angle θ _C changes with the limit value ω _max . Therefore, for example, when the limit value ω _max = 45 degrees, eight instruction steerings are performed for eight control angles θ _C (= θ ₁ , θ ₂ , θ ₃ ,..., Θ ₈ ) that change at intervals of 45 degrees. torque _{^{T * (T * 1, T}} * 2, T * 3, ......, T * 8) and eight of the detected steering torque _{T (= T 1, T 2} , T 3, ......, T 8) is sampled Will be.

When the necessary sampling is completed in this way, the control angle selection unit 29 determines the difference | T ^* _i −T _i | between the command steering torque T ^* and the detected steering torque T for each control angle θ _C (where i is an integer). 1 ≦ i ≦ m) is obtained (step S25). Then, the control angle θ _C that minimizes the difference | T ^* _i− T _i | is selected, replaced with the calculation result of the control angle calculation unit 26, and set as a new control angle θ _C (step S26). . Further, the control angle selection unit 29 resets the internal value (integral term) of the PI control unit 23 to zero, and resets the previous value of the control angle θ _C in the control angle calculation unit 26 (step S27). In this reset process, the addition angle α and the γ-axis command current value I _γ ^* may be initialized to zero together.

As described above, in this embodiment, when the state where the addition angle α is equal to or greater than the threshold value α _th continues and the addition angle monitoring unit 25 notifies the occurrence of an abnormality, the control angle θ _C calculated by the control angle calculation unit 26 is obtained. The control angle θ _C that minimizes the difference between the command steering torque T ^* and the detected steering torque T is selected and used for control. At the same time, the internal value of the PI control unit 23 and the previous value of the control angle θ _C are reset. As a result, the control can be newly restarted from the control angle θ _{C at} which the command steering torque T ^* and the detected steering torque T are approximate. Thereby, it is possible to quickly escape from the abnormal state and converge the control angle θ _C to an appropriate value.

FIG. 12 is a block diagram for explaining a configuration of an electric power steering apparatus according to the second embodiment of the present invention. In FIG. 12, the corresponding parts of the respective parts shown in FIG.
In this embodiment, the limit value changing section 30 to change the limit value omega _max undergoing abnormality occurrence notification from the addition angle monitoring unit 25 from the already value is provided.

FIG. 13 is a flowchart for explaining an operation example of the limit value changing unit 30. When the addition angle monitoring unit 25 notifies the occurrence of abnormality, the limit value changing unit 30, the limit value omega _max from the existing value (e.g. 45 degrees) is changed to another value. The changed limit value ω _max is a value other than a divisor of 360 degrees. Furthermore, limit omega _max after the change is preferably a smaller value than the existing value.

When the addition angle α is subjected to the limit process by the limiter 24, if the limit value ω _max is a divisor of 360 degrees, the control angle θ _C cyclically takes a very limited finite number of values. become. Therefore, the control angle θ _C is difficult to converge to an appropriate value corresponding to the command steering torque T ^* . Therefore, in this embodiment, the limit value ω _max is changed to a value other than a divisor of 360 degrees. As a result, the state where the control angle θ _C cyclically takes a finite number of values can be removed, and the convergence of the control angle θ _{C to} an appropriate value can be promoted.

When the control angle θ _C approaches an appropriate value and the addition angle α is not limited by the limiter 24, the determination in step S31 is denied and the limit value ω _max returns to the default value ( Step S33).
Although it is conceivable that the predetermined value of the limit value ω _max is different from a divisor of 360 degrees, the limit value is used to cause the control angle θ _C to follow the operation of the steering wheel 10 at the maximum steering angular speed. In some cases, the default value of ω _max must be set to a divisor of 360 degrees. In such a case, it is effective to apply the configuration of this embodiment.

FIG. 14 is a flowchart for explaining another operation example of the limit value changing unit 30. When the addition angle monitoring unit 25 notifies the abnormality occurs (step S31: YES), the limit value changing unit 30, the limit value omega _max from the existing value (e.g. 45 degrees) is changed to a value smaller than (step S34). Thereby, since the control angle θ _C varies in small increments, it is possible to take a value that approximates an appropriate value, and therefore it is possible to promote convergence to an appropriate value. Limit omega _max for a predetermined time (e.g., 100 ms) is after changing only a small value (step S35: YES), the limit value omega _max is returned to the existing value (step S33).

If the predetermined value of the limit value ω _max is set to a small value, the control angle θ _C may not be allowed to follow when the steering wheel 10 is operated at high speed. Therefore, the default value of the limit value ω _max is set to a relatively large value so that the control angle θ _C can follow the maximum steering angular velocity with a good response. The limit value ω _max is preferably changed to a small value.

FIG. 15 is a block diagram for explaining the configuration of the electric power steering apparatus according to the reference embodiment. In FIG. 15, the same reference numerals are assigned to the corresponding parts of the respective parts shown in FIG.
In this reference form, when the addition angle monitoring unit 25 notifies the occurrence of an abnormality, an instruction current value correction unit 40 that receives and decreases the instruction current value is provided. In this reference embodiment, the command current value correction unit 40 corrects the γ-axis command current value I _γ ^* to decrease.

FIG. 16 is a flowchart for explaining the operation of the command current value correction unit 40. When the addition angle monitoring unit 25 notifies the occurrence of an abnormality, the command current value correction unit 40 corrects the γ-axis command current value I _γ ^* to decrease. As a result, even if the control angle θ _C is changing every calculation cycle with a predetermined change width of the limit value ω _max , the torque generated by the motor 3 changes little by little. For this reason, the change in the q-axis current is reduced, and the substantial control gain is reduced. As a result, the control angle θ _C easily converges to an appropriate value, so that it is possible to escape from the abnormal state in which the addition angle α is continuously limited by the limiter 24.

FIG. 17 is a block diagram for explaining a configuration of an electric power steering apparatus according to another reference embodiment. In FIG. 17, the same reference numerals are given to the corresponding parts of the respective parts shown in FIG. 1 described above.
In this reference form, the addition angle monitoring unit 25 is provided with an initialization unit 41 that executes an initialization process in response to the occurrence of an abnormality.

FIG. 18 is a flowchart for explaining the operation of the initialization unit 41. When the addition angle monitoring unit 25 notifies the occurrence of an abnormality, the initialization unit 41 performs a predetermined initialization process. In this reference form, this initialization process is performed in (a) resetting the integral value (integral term) in the PI control unit 23, (b) resetting the addition angle α calculated by the PI control unit 23, and (c) the control angle. This includes resetting the previous value (control angle θ _C in the previous calculation cycle) in the calculation unit 26.

By performing such initialization processing, it is possible to quickly escape from the state where the addition angle α continues to receive the limit processing by the limiter 24 and to resume control. Thereby, the convergence of the control angle θ _{C to} an appropriate value can be promoted.
Having described implementation form and reference embodiment of the present invention, it is possible other shapes state in further. For example, in the above-described embodiment and the reference embodiment , the addition angle monitoring unit 25 monitors the continuation of the state where the absolute value of the addition angle α is equal to or greater than the threshold value α _th , but the limiter 24 limits it. It is also possible to adopt a configuration for monitoring the duration of the state in which it is applied.

In the above-described embodiment and reference embodiment, the configuration in which the motor 3 is driven exclusively by sensorless control without the rotation angle sensor has been described. However, the rotation angle sensor such as a resolver is provided, and when this rotation angle sensor fails The sensorless control as described above may be performed. Thereby, since the drive of the motor 3 can be continued even when the rotation angle sensor fails, the steering assist can be continued. That is, even if a rotation angle sensor is provided, a configuration in which the motor is controlled without using the detection value of the rotation angle sensor is included in the scope of the present invention.
In this case, when the rotation angle sensor is used, the command current value generation units 31 and 31A may generate the δ-axis command current value I _δ ^* according to a predetermined assist characteristic according to the steering torque and the vehicle speed.

When using the output signal of the rotation angle sensor, it is not necessary to introduce the control angle θ _C because the rotor angle θ _M is obtained, and it is not necessary to use a virtual rotation coordinate system according to the control angle θ _C. That is, the d-axis current and the q-axis current may be controlled. However, if both a γδ current control unit that performs current control according to the γδ axis and a dq current control unit that performs current control according to the dq axis are provided, many of the memories (ROM) for storing programs in the microcomputer 11 Will use space. Therefore, it is preferable to share the γδ current control unit and the dq current control unit by sharing the angle variable. Specifically, the angle variable of the common current control unit may be switched so as to be used as the dq coordinate angle when the rotation angle sensor is normal and to be used as the γδ coordinate angle when the rotation angle sensor fails. Thereby, since the amount of memory used can be suppressed, the memory capacity can be reduced accordingly, and the cost can be reduced.

Further, in the above-described embodiment and reference embodiment , the example in which the present invention is applied to the electric power steering apparatus has been described. However, the present invention is not limited to the motor control and the power steering apparatus for the electric pump hydraulic power steering apparatus. Besides, it can be used for control of a brushless motor provided in a steer-by-wire (SBW) system, a variable gear ratio (VGR) steering system, and other vehicle steering devices. Of course, the motor control device of the present invention can be applied not only to the vehicle steering device but also to control a motor for other purposes.

In addition, various design changes can be made within the scope of matters described in the claims.
The features that can be extracted from the description of this specification and the drawings will be added below.
A1. A motor control device for controlling a motor (3) including a rotor (50) and a stator (55) facing the rotor, and rotating according to a control angle (θ _C ) which is a control rotation angle coordinate system axis current value of a current drive unit that drives the motor at ^{_{(I γ *) (31~36)}} , at every predetermined calculation cycle by adding the addition angle (alpha) to the previous value of the control angle A motor control device comprising control angle calculation means (26) for obtaining a current value of the control angle and monitoring means (25) for monitoring the state of the addition angle. In addition, the alphanumeric characters in parentheses indicate corresponding components in the above-described embodiment or reference embodiment. same as below.
According to this configuration, the axis current value (hereinafter “virtual axis”) of the rotating coordinate system (γδ coordinate system, hereinafter referred to as “virtual rotating coordinate system”, the coordinate axis of this virtual rotating coordinate system being referred to as “virtual axis”) according to the control angle. While the motor is driven by the "shaft current value"), the control angle is updated by adding the addition angle every calculation cycle. Thus, the necessary torque can be generated by driving the motor with the virtual axis current value while updating the control angle, that is, while updating the coordinate axis (virtual axis) of the virtual rotation coordinate system. Thus, an appropriate torque can be generated from the motor without using a rotation angle sensor. The addition angle is, for example, a value corresponding to a torque to be generated by the motor or a response of the motor to the virtual axis current value.
Further, the state of the addition angle is monitored by the monitoring means. Therefore, based on the monitoring result, it can be determined whether there is an abnormality in control.
A2. The motor control apparatus according to A1, wherein the monitoring unit includes a unit (S11, S12) that determines that an abnormality occurs when the number of times that the absolute value of the addition angle is equal to or greater than a predetermined threshold continues for a predetermined number of times.
According to this configuration, when the absolute value of the addition angle is continuously equal to or greater than the predetermined threshold value for a predetermined number of times, it is determined that there is an abnormality. When the state where the absolute value of the addition angle is large continues for a long time, the state where the fluctuation of the control angle is large continues and the control angle cannot be converged to the appropriate value. I can judge.
The predetermined number of times may be determined according to the longest time (the longest time assumed in a normal state) that the absolute value of the addition angle may continue at the threshold value or more and the calculation cycle.
After all, the function of the monitoring means is that the control angle continues to fluctuate for a certain time with a fluctuation width equal to or greater than the threshold, in other words, the control angle fluctuates for a certain angle with a fluctuation width greater than the threshold. This is a function to judge that an abnormality occurs when a state of continuing to occur occurs.
A3. The motor control device according to A2, further comprising control angle correction means (27, 29) for correcting the control angle when the abnormality is determined.
According to this configuration, the control angle is corrected when an abnormality occurs. For example, when the addition angle takes a constant value (the absolute value is a value equal to or greater than the threshold value), the control angle may cyclically take a finite number of values. In such a situation, there is a possibility that the state in which the control angle changes by jumping over the appropriate value according to the required torque may continue, and therefore the control angle may not be able to be a value close to the appropriate value. . Therefore, when an abnormality occurs, the control angle is corrected and the control angle is forcibly shifted. As a result, the possibility that the control angle takes a value close to an appropriate value is increased, and accordingly, the control angle is easily converged to an appropriate value corresponding to the required torque. In this way, it can be urged to get out of the abnormal state.
A4. The motor control device according to A2, further comprising addition angle correction means (28) for correcting the addition angle when the abnormality is determined.
In this configuration, the same effect as the configuration of A3 is achieved by correcting the addition angle.
When the motor control device includes addition angle calculation means (22, 23) for calculating the addition angle, the addition angle correction means changes the calculation angle of the addition angle calculation means to change the addition angle. You may correct | amend. More specifically, the motor control device includes an instruction torque setting means (21) for setting an instruction torque to be applied to a driving target of the motor, and a torque detection for detecting a torque (detected torque) acting on the driving target. Means (1) may be included. In this case, the addition angle calculation means may include feedback control means (22, 23) for calculating the addition angle so that the detected torque approaches the instruction torque. The addition angle correction means may change the gain of the feedback control means.
A5. The control angle correction means (29) further includes an instruction torque setting means (21) for setting an instruction torque to be applied to the drive target of the motor, and a torque detection means (1) for detecting a torque acting on the drive object. ) Means for sampling the command torque set by the command torque setting means and the torque detected by the torque detection means (S23, S24) for a plurality of control angles, and among the control angles, The motor control device according to A3, further comprising control angle selection means (S26) that selects a control angle that minimizes a difference between the sampled instruction torque and the detected torque and sets the control angle as a new control angle.
According to this configuration, when it is determined that there is an abnormality, the command torque and the detected torque are sampled for a plurality of control angles. Then, the control angle that minimizes the difference between the command torque and the detected torque is selected as a new control angle. As a result, the control angle can be set to a value approximate to an appropriate value that can bring the detected torque close to the command torque, and thus the convergence of the control angle to the appropriate value can be promoted.
A6. An addition angle limiting means (24) for limiting the absolute value of the addition angle based on a predetermined limit value (default value), and the limit value is changed when it is determined as abnormal (changed from the default value) The motor control device according to A2, further including limit value changing means (30).
According to this configuration, by adding an appropriate limit to the addition angle, it is possible to suppress an excessive addition angle from being added to the control angle as compared to the actual rotation of the rotor. More specifically, the motor can be controlled more appropriately by adding a restriction so that the addition angle is set within a reasonable range with respect to the rotational speed range of the rotor. On the other hand, when it is determined as abnormal, the limit value is changed from a predetermined limit value (default value). If the addition angle is limited by a certain limit value, there is a possibility that the control angle may cyclically take a finite number of values, which may make it difficult to converge the control angle to an appropriate value. Therefore, when the abnormality occurs, the limit value is changed from the default value, and the convergence of the control angle to an appropriate value can be promoted.
The predetermined limit value (predetermined value) may be a value determined by the following equation, for example. However, the “maximum rotor angular velocity” in the following equation is the maximum value of the rotor angular velocity in electrical angle.
Predetermined limit value (default) = maximum rotor angular speed x calculation cycle
For example, when the rotation of the motor is transmitted to the steering shaft of the vehicle steering device via a speed reduction mechanism with a predetermined reduction ratio, the maximum rotor angular velocity is the maximum steering angular velocity (maximum rotational angular velocity of the steering shaft) × deceleration It is given as ratio x number of pole pairs. The “number of pole pairs” is the number of magnetic pole pairs (pairs of N poles and S poles) that the rotor has.
A7. The motor control device according to A6, wherein the changed limit value is a value that is not a divisor of 360 degrees.
According to this configuration, the changed limit value is not a divisor of 360 degrees. For this reason, even if the absolute value of the addition angle is limited to the changed limit value, the control angle does not cyclically take a limited number of decimal values. Thereby, the possibility that the control angle approaches the appropriate value can be increased, and the convergence of the control angle to the appropriate value can be promoted.
A8. The motor control device according to A6, wherein the changed limit value is a value smaller than the predetermined limit value (predetermined value).
According to this configuration, when it is determined that there is an abnormality, the possibility that the control angle approaches the appropriate value is increased by setting the limit value to a value smaller than the predetermined limit value (predetermined value). . Thereby, convergence of the control angle to an appropriate value can be promoted.
A9. The motor control device according to A2, further comprising current limiting means (40) for reducing the motor command current value when it is determined that the abnormality is present.
According to this configuration, the motor command current is reduced when an abnormality occurs. Thereby, the tendency of control to diverge can be suppressed, and the control system can be led to a converged state.
A10. The motor control device according to A2, further comprising means (41) for resetting the addition angle, the control angle, and the motor command current value when it is determined that the abnormality has occurred.
According to this configuration, if it is determined that there is an abnormality, the addition angle, the control angle, and the motor command current value are reset, so that the abnormal state can be quickly removed and the control can be resumed.
The motor may provide a driving force to the steering mechanism (2) of the vehicle. In this case, the motor control device detects torque steering means (1) for detecting a steering torque applied to the operating member (10) operated for steering the vehicle, and command steering for setting command steering torque. Torque setting means (21) and addition angle calculation means (22) for calculating the addition angle according to a deviation between the command steering torque set by the command steering torque setting means and the steering torque detected by the torque detection means. , 23).
According to this configuration, the command steering torque is set, and the addition angle is calculated according to the deviation between the command steering torque and the steering torque (detected value). Thus, the addition angle is determined so that the steering torque becomes the command steering torque, and the control angle corresponding to the addition angle is determined. Therefore, by appropriately determining the instruction steering torque, it is possible to generate an appropriate driving force from the motor and apply it to the steering mechanism. That is, the deviation (load angle) between the coordinate axis of the rotating coordinate system (dq coordinate system) and the virtual axis according to the magnetic pole direction of the rotor is led to a value corresponding to the command steering torque. As a result, an appropriate torque is generated from the motor, and a driving force according to the driver's steering intention can be applied to the steering mechanism.
In a vehicle steering apparatus (for example, an electric power steering apparatus) in which an operation member and a steering mechanism are mechanically coupled, the motor response (torque generated by the motor) to the virtual axis current value is the change in the detected steering torque. It appears. Therefore, in such a vehicle steering apparatus, it can be said that calculating the addition angle in accordance with the detected steering torque calculates the addition angle in accordance with the motor response to the virtual axis current value.
The motor control device further includes a steering angle detection means (4) for detecting a steering angle of the operation member, and the instruction steering torque setting means indicates instruction steering according to a steering angle detected by the steering angle detection means. The torque is preferably set. According to this configuration, since the instruction steering torque is set according to the steering angle of the operation member, an appropriate torque according to the steering angle can be generated from the motor, and the steering torque applied to the operation member by the driver can be increased. The value can be derived according to the steering angle. Thereby, a favorable steering feeling can be obtained.
The command steering torque setting unit may set the command steering torque according to the vehicle speed detected by the vehicle speed detection unit (6) that detects the vehicle speed of the vehicle. According to this configuration, since the command steering torque is set according to the vehicle speed, so-called vehicle speed sensitive control can be performed. As a result, a good steering feeling can be realized. For example, an excellent steering feeling can be obtained by setting the command steering torque to be smaller as the vehicle speed is higher, that is, at higher speeds.

It is a block diagram for demonstrating the electrical structure of the electric power steering apparatus to which the motor control apparatus which concerns on a reference form is applied. It is an illustration figure for demonstrating the structure of a motor. It is a control block diagram of the electric power steering device. It is a figure which shows the example of a characteristic of the instruction | indication steering torque with respect to a steering angle. It is a figure which shows the example of a setting of (gamma) axis instruction | indication electric current value. It is a flowchart for demonstrating the function of a limiter. It is a flowchart for demonstrating the process by an addition angle monitoring part and a control angle correction | amendment part. It is a block diagram for demonstrating the structure of the electric power steering apparatus which concerns on another reference form. It is a flowchart for demonstrating the process by an addition angle monitoring part and a gain change part. It is a block diagram for demonstrating the structure of the electric power steering apparatus which concerns on 1st Embodiment of this invention. It is a flowchart for demonstrating the process by a control angle selection part. It is a block diagram for demonstrating the structure of the electric power steering apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart for demonstrating the operation example of a limit value change part. It is a flowchart for demonstrating the other operation example of a limit value change part. It is a block diagram for demonstrating the structure of the electric power steering apparatus which concerns on other reference form. It is a flowchart for demonstrating operation | movement of a command electric current value correction | amendment part. It is a block diagram for demonstrating the structure of the electric power steering apparatus which concerns on other reference embodiment. It is a flowchart for demonstrating operation | movement of the initialization part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Torque sensor, 3 ... Motor, 4 ... Steering angle sensor, 5 ... Motor control apparatus, 11 ... Microcomputer, 26 ... Control angle calculating part, 50 ... Rotor, 51, 52, 52 ... Stator winding, 55 ... Stator

Claims (4)

A motor control device for controlling a motor including a rotor and a stator facing the rotor without using a detection value of a rotation angle sensor for detecting the rotation angle of the rotor ,
An instruction torque setting means for setting an instruction torque to be applied to the driving target of the motor;
Torque detecting means for detecting torque acting on the drive object;
Current driving means for driving the motor with an axial current value of a rotating coordinate system according to a control angle that is a control rotation angle;
An addition angle calculation means for calculating an addition angle to be added to the control angle according to a deviation between the instruction torque set by the instruction torque setting means and the torque detected by the torque detection means;
Control angle calculation means for obtaining the current value of the control angle by adding the addition angle calculated by the addition angle calculation means to the previous value of the control angle for each predetermined calculation cycle;
Monitoring means for monitoring the state of the addition angle and determining an abnormality when the number of times that the absolute value of the addition angle is equal to or greater than a predetermined threshold continues for a predetermined number of times;
And a control angle correction unit that corrects the control angle when it is determined that the abnormality,
The control angle correction means includes
Means for sampling the instruction torque set by the instruction torque setting means and the detection torque detected by the torque detection means for a plurality of control angles;
A motor control device comprising: a control angle selection unit that selects a control angle that minimizes a difference between the sampled instruction torque and the detected torque from among the plurality of control angles and sets the selected control angle as a new control angle. A motor control device for controlling a motor including a rotor and a stator facing the rotor without using a detection value of a rotation angle sensor for detecting the rotation angle of the rotor ,
An instruction torque setting means for setting an instruction torque to be applied to the driving target of the motor;
Torque detecting means for detecting torque acting on the drive object;
Current driving means for driving the motor with an axial current value of a rotating coordinate system according to a control angle that is a control rotation angle;
An addition angle calculation means for calculating an addition angle to be added to the control angle according to a deviation between the instruction torque set by the instruction torque setting means and the torque detected by the torque detection means;
Control angle calculation means for obtaining the current value of the control angle by adding the addition angle calculated by the addition angle calculation means to the previous value of the control angle for each predetermined calculation cycle;
Monitoring means for monitoring the state of the addition angle and determining an abnormality when the number of times that the absolute value of the addition angle is equal to or greater than a predetermined threshold continues for a predetermined number of times;
Addition angle limiting means for limiting the absolute value of the addition angle based on a predetermined limit value;
A motor control device including limit value changing means for changing the limit value when the abnormality is determined.   The motor control device according to claim 2, wherein the changed limit value is a value that is not a divisor of 360 degrees.   The motor control device according to claim 2, wherein the changed limit value is a value smaller than the predetermined limit value.

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