JP6986903B2 - Electric linear actuator and electric brake device - Google Patents

Description

The present invention relates to, for example, an electric linear actuator and an electric brake device mounted on a vehicle or the like, and relates to a technique capable of performing space-saving and high-output motor control.

The following technologies have been proposed as electric linear actuators.
1. 1. An actuator for an electric brake using an electric motor, a linear motion mechanism and a speed reducer (Patent Document 1).
2. 2. An electric actuator using a planetary roller mechanism and an electric motor (Patent Document 2).

Japanese Unexamined Patent Publication No. 6-327190 Japanese Unexamined Patent Publication No. 2006-194356

In electric linear actuators such as Patent Documents 1 and 2, when used in applications that require high-speed, high-precision response, such as electric braking devices, the desired output can be obtained within the limited mounting space of the vehicle. It can be difficult to obtain.
In particular, in the case of the above-mentioned electric brake device, it is necessary to obtain a desired actuator thrust (that is, torque) and output after being configured so as not to interfere with surrounding wheels, a suspension device, or the like. At this time, when trying to exhibit high output at the maximum motor current generally defined as a constant value, the motor size becomes large, and an increase in mounting space and cost may become a problem.

An object of the present invention is to provide an electric linear actuator and an electric brake device capable of miniaturizing an electric motor and performing space-saving and high-output motor control.

The electric linear actuator DA of the present invention includes an electric motor 4, a linear motion mechanism 6 that converts the rotational motion of the electric motor 4 into linear motion of the linear motion unit 14, and a control device 2 that controls the electric motor 4. In an electric linear actuator equipped with
The control device 2 is
The angular velocity estimation function unit 20b for estimating the angular velocity of the electric motor 4 and
The current limiting function unit 23a that limits the current energizing the electric motor 4 to a predetermined maximum value, and
It has a maximum current adjusting function unit 24 that increases the maximum value of the current limited by the current limiting function unit 23a when the angular velocity estimated by the angular velocity estimation function unit 20b becomes larger than a predetermined angular velocity.
The specified maximum value and the specified angular velocity are the maximum value and the angular velocity arbitrarily determined by the design and the like, respectively, and for example, the appropriate maximum value and the angular velocity are obtained by one or both of the test and the simulation. Is determined.

According to this configuration, the angular velocity estimation function unit 20b estimates the angular velocity of the electric motor 4. The current limiting function unit 23a limits the current energizing the electric motor 4 to a predetermined maximum value (maximum current value). The maximum current adjustment function unit 24 determines whether or not the estimated angular velocity (estimated angular velocity) is larger than the predetermined angular velocity. When the estimated angular velocity is less than or equal to the specified angular velocity, the specified maximum current value is maintained. The maximum current adjusting function unit 24 temporarily increases the maximum current value when the estimated angular velocity is larger than the predetermined angular velocity.

By increasing the maximum current value in the region where the angular velocity of the electric motor 4 is large in this way, the motor output is increased and high-speed response is possible. Therefore, it is possible to reduce the size of the electric motor 4 and perform space-saving and high-output motor control.
For example, in an actuator that controls the position (load) such as the electric brake device 1, the motor angular speed becomes relatively large in a limited situation such as panic braking or anti-skid control, so that the electric motor 4 is energized. Even if the current is temporarily increased, the heat load on the electric motor 4 is slight, and there is no problem in durability.

In the control device 2, when the angular velocity estimated by the angular velocity estimation function unit 20b becomes larger than the defined angular velocity, the estimated angular velocity is increased with respect to the axial current converted as a vector component in the orthogonal axis on the rotating coordinate system. It has a current vector control function that changes the phase of the shaft current vector in the direction inverted from the magnetic field vector phase of the rotor in the electric motor 4 as compared with the phase of the shaft current vector when the angular velocity is equal to or lower than the predetermined angular velocity. death,
The maximum current adjusting function unit 24 is
Regarding the maximum current locus of the shaft current vector, which is a norm corresponding to the maximum value of the current of the electric motor 4.
A non-perfect circular ellipse whose longitudinal direction is the vector direction that passes through the point that becomes the maximum current vector that maximizes the torque per current when the estimated angular velocity is approximately zero and that substantially coincides with the magnetic field of the rotor. The maximum current may be increased so as to form a trajectory.

According to this configuration, the current vector control function uses field weakening control that shifts the axial current vector in the direction of −180 degrees in the phase on the dq axis when the estimated angular velocity becomes large. In this case, the maximum current adjusting function unit 24 sets the maximum current locus of the axis current vector corresponding to the maximum current as an elliptical locus with the d-axis in the substantially longitudinal direction. As a result, by increasing the maximum current value in the region where the motor angular velocity is large, the motor output is increased and high-speed response is possible.

In the control device 2, when the angular velocity estimated by the angular velocity estimation function unit 20b becomes larger than the defined angular velocity, the estimated angular velocity is increased with respect to the axial current converted as a vector component in the orthogonal axis on the rotating coordinate system. It has a current vector control function that changes the phase of the shaft current vector in the direction inverted from the magnetic field vector phase of the rotor in the electric motor 4 as compared with the phase of the shaft current vector when the angular velocity is equal to or lower than the predetermined angular velocity. death,
The maximum current adjusting function unit 24 is
Regarding the maximum current locus of the shaft current vector, which is a norm corresponding to the maximum value of the current of the electric motor 4.
When the estimated angular velocity is substantially zero, the linear locus passes through the point where the torque per current becomes the maximum current vector, and the vector direction substantially coincides with the magnetic field of the rotor is used as the apex. The maximum current may be increased.

According to this configuration, the current vector control function uses field weakening control that shifts the axial current vector in the direction of −180 degrees in the phase on the dq axis when the estimated angular velocity becomes large. In this case, the maximum current adjusting function unit 24 sets the maximum current locus of the axis current vector corresponding to the maximum current as a linear locus with the apex on the d-axis. As a result, by increasing the maximum current value in the region where the motor angular velocity is large, the motor output is increased and high-speed response is possible.

The control device 2 is a power supply monitoring function unit that determines the power supply capacity of the power supply device 3 by using one or both of the voltage and the current of the power supply device 3 that supplies the power for driving the electric motor 4. 26, the maximum current adjusting function unit 24 may increase the maximum value of the current when the power supply capacity determined by the power supply monitoring function unit 26 is higher than a predetermined value.
The predetermined value is a value arbitrarily determined by design or the like, and is determined by obtaining an appropriate value by, for example, one or both of a test and a simulation.

In this case, the maximum current can be increased only when the power supply device 3 is normal and has sufficient power supply capacity. For example, when an abnormality occurs in the power supply device 3, it is possible to prevent the electric linear actuator DA from becoming unusable due to excessive power consumption. Therefore, the redundancy of the electric linear actuator DA can be increased.

The electric brake device 1 of the present invention exerts a braking force by contact between the electric linear actuator DA according to any one of the above, the friction material 9 operated by the electric linear actuator DA, and the friction material 9. It includes a brake rotor 8 to generate the brake rotor 8. According to the electric brake device 1, since any of the electric linear actuator DAs is provided, it is possible to control the motor in a small space and with high output.

The electric linear motion actuator of the present invention includes an electric motor, a linear motion mechanism that converts the rotational motion of the electric motor into a linear motion of a linear motion unit, and a control device that controls the electric motor. In the dynamic actuator, the control device includes an angular speed estimation function unit that estimates the angular speed of the electric motor, a current limiting function unit that limits the current energizing the electric motor to a predetermined maximum value, and the angular speed estimation function unit. It has a maximum current adjusting function unit that increases the maximum value of the current limited by the current limiting function unit when the angular speed estimated in 1 becomes larger than the predetermined angular speed. Therefore, it is possible to reduce the size of the electric motor and perform space-saving and high-output motor control.

The electric brake device of the present invention includes the electric linear acting actuator according to any one of the above, a friction material operated by the electric linear motion actuator, and a brake rotor that generates a braking force by contact with the friction material. , It is possible to reduce the size of the electric motor and perform space-saving and high-output motor control.

It is a figure which shows schematic the electric brake device which concerns on embodiment of this invention. It is a block diagram of the control system of the electric linear actuator of the electric brake device. It is a figure which shows the example of the locus of the current norm on the dq axis by the maximum current adjustment function part of the electric direct-acting actuator. It is a block diagram which shows the example which executes the same maximum current adjustment function part. It is a block diagram of the control system of the electric linear actuator of the electric brake device which concerns on other embodiment of this invention. It is a figure which shows the example of the locus of the current norm on the dq axis by the maximum current adjustment function part of the electric linear actuator which concerns on still another Embodiment of this invention. It is a figure which shows the example of the locus of the current norm on the dq axis by the maximum current adjustment function part of the electric linear actuator which concerns on still another Embodiment of this invention. It is a block diagram which shows the example which executes the maximum current adjustment function part of the electric linear actuator which concerns on still another Embodiment of this invention.

The electric brake device according to the embodiment of the present invention will be described with reference to FIGS. 1 to 4. This electric braking device is mounted on a vehicle, for example.
As shown in FIG. 1, the electric brake device 1 includes an electric linear actuator DA and a friction brake BR. First, the structures of the electric linear actuator DA and the friction brake BR will be described.

<Structure of electric linear actuator DA and friction brake BR>
As shown in FIGS. 1 and 2, the electric linear actuator DA includes an actuator main body AH, a power supply device 3, and a control device 2 described later. The actuator main body AH includes an electric motor 4, a deceleration mechanism 5, a linear motion mechanism 6, a parking brake device 7, an angle sensor Sa, and a load sensor Sb.

As shown in FIG. 1, the electric motor 4 comprises, for example, a permanent magnet type synchronous motor. When a permanent magnet type synchronous motor is applied as the electric motor 4, it is suitable because it saves space and produces high torque.
The friction brake BR has a brake rotor 8 that rotates in conjunction with the wheels of the vehicle, and a friction material 9 that comes into contact with the brake rotor 8 to generate braking force. The friction material 9 is operated by an electric linear actuator DA. A mechanism can be used in which the friction material 9 is operated by the actuator main body AH of the electric linear acting actuator DA to press the friction material 9 against the brake rotor 8 and generate a braking force by the frictional force.

The speed reduction mechanism 5 is a mechanism for reducing the rotation of the electric motor 4, and includes a primary gear 12, an intermediate gear 13, and a tertiary gear 11. In this example, the reduction mechanism 5 decelerates the rotation of the primary gear 12 attached to the rotor shaft 4a of the electric motor 4 by the intermediate gear 13 and transmits the rotation to the tertiary gear 11 fixed to the end of the rotation shaft 10. It is possible.

The linear motion mechanism 6 is a mechanism that converts the rotary motion output by the deceleration mechanism 5 into a linear motion of the linear motion portion 14 by the feed screw mechanism, and causes the friction material 9 to abut and separate from the brake rotor 8. The linear motion portion 14 is detented and is movably supported in the axial direction indicated by the arrow A1. A friction material 9 is provided at the outboard side end of the linear motion portion 14. By transmitting the rotation of the electric motor 4 to the linear motion mechanism 6 via the reduction mechanism 5, the rotational motion is converted into a linear motion, which is converted into the pressing force of the friction material 9 to generate a braking force. .. With the electric brake device 1 mounted on the vehicle, the outside of the vehicle in the vehicle width direction is referred to as the outboard side. The center side of the vehicle in the width direction is called the inboard side.

As the actuator 16 of the parking brake mechanism 7, for example, a linear solenoid is applied. A parking lock state is achieved by advancing the lock member 15 by the actuator 16 and fitting it into a locking hole (not shown) formed in the intermediate gear 13 to lock the intermediate gear 13 and prohibiting the rotation of the intermediate gear 13. To. By disengaging the lock member 15 from the locking hole, the intermediate gear 13 is allowed to rotate and is brought into an unlocked state.

As shown in FIG. 2, the angle sensor Sa detects the rotation angle of the electric motor 4. As the angle sensor Sa, for example, it is suitable to use a resolver or a magnetic encoder because of high accuracy and high reliability, but various sensors such as an optical encoder can also be used. Instead of using the angle sensor Sa, in the control device 2 described later, angle sensorless estimation that estimates the motor angle from the relationship between the voltage and the current of the electric motor 4 can also be used.

The load sensor Sb detects the axial load of the linear motion mechanism 6. As the load sensor Sb, for example, a magnetic sensor, a strain sensor, a pressure sensor, or the like that detects the displacement or deformation of a predetermined member on which the load of the linear motion mechanism 6 acts can be used. Instead of using the load sensor Sb, the control device 2 may perform load sensorless estimation from, for example, the motor angle and the rigidity of the electric brake device, the motor current, the efficiency of the electric linear actuator, and the like. Alternatively, it may be another external sensor such as a sensor that detects the wheel torque of the wheel on which the brake is mounted or the front-rear force of the vehicle equipped with the electric brake device 1 (FIG. 1). Further, various sensors such as a thermistor may be separately provided as needed.

<Configuration of control device 2>
FIG. 2 is a block diagram of a control system of the electric linear actuator DA of this electric brake device. For example, a control device 2 and an actuator main body AH corresponding to each wheel are provided. Each control device 2 controls the corresponding electric motor 4. A DC power supply device 3 and a higher-level ECU 17 which is a higher-level control means of each control device 2 are connected to each control device 2. The power supply device 3 supplies electric power to the electric motor 4 and the control device 2. As the power supply device 3, for example, a low voltage (for example, 12 V) battery of a vehicle equipped with the electric brake device 1 (FIG. 1) may be applied.

As the upper ECU 17, for example, an electric control unit (Vehicle Control Unit, VCU) that controls the entire vehicle is applied. The upper ECU 17 has an integrated control function for each control device 2. The upper ECU 17 includes a command means 17a, and the command means 17a outputs a target load command value to each control device 2 according to the output of a sensor that changes according to the operation amount of the brake operating means (not shown). do. The command means 17a may be the brake operation means itself, or the command means 17a may be, for example, a load command value (brake force command) to each control device 2 by determining braking in the autonomous driving vehicle without depending on the operation of the brake operation means. It is also possible to output each value).

Each control device 2 includes various control calculation function units that perform control calculations, and a motor driver 18. The various control calculation function units are composed of, for example, a processor such as a microcomputer, a calculation unit such as FPGA or ASIC, and peripheral circuits. The various control calculation function units include a load estimation function unit 19, a motion estimation function unit 20, a current estimation function unit 21, a load control function unit 22, a current command function unit 23, a maximum current adjustment function unit 24, and a current control function unit 25. To prepare for.

The load estimation function unit 19 estimates the axial load (estimated load) of the linear motion mechanism 6 from the output of the load sensor Sb and the like. Alternatively, when performing load sensorless estimation, the load estimation function unit 19 may be configured to estimate the axial load of the linear motion mechanism 6 using information such as the motor angle and the current.
The motion estimation function unit 20 estimates the rotational motion state of the electric motor 4 from the output of the angle sensor Sa and the like. The motion estimation function unit 20 has a position / phase estimation function unit 20a and an angular velocity estimation function unit 20b.

When the position / phase estimation unit 20a uses, for example, a sensor such as a resolver or an encoder that detects a predetermined angle region as one cycle as the angle sensor Sa, the rotor phase of the electric motor 4 is estimated from the output of the angle sensor Sa. Then, the integrated value of the fluctuation amount of the rotor phase may be estimated as the total rotation angle (position). Further, the angular velocity estimation function unit 20b may estimate the differential equivalent value of the rotor phase or position as the angular velocity. Alternatively, for example, when performing the above-mentioned angle sensorless estimation, the phase, angular velocity, and the like may be estimated from the voltage and current of the electric motor 4.

The current estimation function unit 21 estimates the motor current. The current estimation function unit 21 may estimate the motor current by using, for example, a current sensor (not shown) provided on the energization path of the phase current of the electric motor 4. As the current sensor, a contact type sensor such as a shunt resistor and an amplifier, or a non-contact type sensor such as a magnetic sensor arranged near the energization path can be used.

The current sensor may be arranged so as to detect, for example, the three-phase motor phase current, and the remaining one phase is due to the relationship that the two phases of the three-phase motor phase current are detected and the total of the three phases becomes zero. May be arranged to detect.
Alternatively, the current estimation function unit 21 may be a current sensorless estimation that estimates the motor current from the motor voltage and the motor coil characteristics, or, for example, the current sensor, the voltage, and the motor that detect the primary current on the plus side or the minus side. A combination of current sensor and current sensorless estimation, such as estimating the motor phase current from the coil characteristics, may be used.

The load control function unit 22 causes the electric motor 4 to follow the estimated load calculated by the load estimation function unit 19 with respect to the target load command value (actuator load command) given by the command means 17a. Control the amount of operation. The manipulated variable may be, for example, a target motor torque or a current norm. In particular, when the motor torque is used as the operation amount, the current command function unit 23, which will be described later, may have a function of a current converter for the torque.

The current command function unit 23 has a function of generating a target current of the electric motor 4. The current command function unit 23 has a current limit function unit 23a and a command current calculation unit 23b. The current limiting function unit 23a limits the magnitude of the current energizing the electric motor 4 to a predetermined maximum value. The current limiting function unit 23a of this example has a function of limiting the target current so that the magnitude of the motor current is equal to or less than a predetermined value. The command current calculation unit 23b may have a function of generating a current command value in the current control function unit 25, which will be described later, within the range of the current limit by the current limit function unit 23a.

The current command value may be, for example, a current vector on an orthogonal axis on a predetermined rotational coordinate system as a command value or a three-phase alternating current command value, but in particular, the former coincides with the rotor magnetic flux. It is preferable to use an axis current corresponding to the d-axis and the q-axis orthogonal to the d-axis because a simple and high-performance current control system can be configured.

The maximum current adjusting function unit 24 can have a function of varying the current limiting current in the current command function unit 23 according to the conditions. The maximum current adjusting function unit 24 has a function of increasing the maximum value of the current limited by the current limiting function unit 23a when the angular velocity estimated by the angular velocity estimation function unit 20b becomes larger than the predetermined angular velocity. The function of increasing the maximum current value improves the maximum output of the electric motor 4, and enables high-speed response in the electric linear actuator DA.

The current control function unit 25 may have a function of controlling the motor voltage so that the estimated current estimated by the current estimation function unit 21 follows the current command value.
The motor driver 18 controls the electric power supplied to the coil of the electric motor 4. The motor driver 18 constitutes, for example, a half-bridge circuit using a switch element such as a field effect transistor (abbreviated as FET), and PWM control in which the voltage applied to the motor is determined by the ON-OFF duty ratio of the switch element. If it is configured to perform the above, it will be inexpensive and have high performance. Alternatively, a transformer circuit or the like may be provided to perform PAM control.

In addition, configurations of current sensors and the like (not shown) can be appropriately provided as needed. Further, each functional unit is provided as a block for convenience, and may be integrated or divided as necessary, or a predetermined functional unit may be omitted as appropriate.

<Example of current limit vector>
FIG. 3 is a diagram showing an example of the locus of the current norm on the dq axis by the maximum current adjusting function unit of this electric linear actuator. FIG. 2 will also be described with reference to the appropriate reference. It is assumed that the d-axis in FIG. 3 coincides with the direction of the rotor magnetic flux when no load is applied.

In the example of FIG. 3, the maximum current adjusting function unit 24 has an elliptical locus as the maximum current norm corresponding to the maximum value of the current of the electric motor 4. That is, the maximum current adjusting function unit 24 passes through the maximum current phase (θmax) at which the torque per current is maximum, and has a non-perfect circular elliptical locus Kd whose longitudinal direction is approximately the negative d-axis direction (weak magnetic flux direction). Change the maximum current so that The dotted line, which is a perfect circle in the figure, shows the trajectory when the conventional maximum current (current limit) is constant.

The maximum current phase (θmax) is approximately 90 °, particularly in a surface magnet type synchronous motor, and a predetermined phase angle in a motor having a salient polarity represented by an embedded magnet type synchronous motor. In general, the maximum current locus of the axial current vector is often a symmetric locus in which the torque direction is reversed with respect to the d-axis, but the maximum current is asymmetrical with respect to the d-axis and the maximum current differs depending on the torque direction. May be good. Alternatively, different trajectories can be applied for power running and regeneration.

In this control device 2, when the angular velocity estimated by the angular velocity estimation function unit 20b becomes larger than the predetermined angular velocity, a control method (weakening magnetic flux control) is used in which the negative d-axis current is increased to suppress the induced voltage. .. In other words, when the estimated angular velocity becomes larger than the defined angular velocity, the control device 2 receives the axial current converted as a vector component in the orthogonal axis on the rotating coordinate system when the estimated angular velocity is equal to or less than the defined angular velocity. It has a current vector control function that changes the phase of the shaft current vector in the direction inverted from the magnetic field vector phase of the rotor in the electric motor 4 as compared with the phase of the shaft current vector.

Therefore, when the control device 2 has the current vector control function, the maximum current when the angular velocity increases by making the maximum current locus of the axial current vector, which is the maximum current norm, an elliptical shape as shown in FIG. The value can be increased and the motor output can be improved.

As a trade-off, the heat load on the electric motor 4 increases as the maximum current value increases. However, in an electric linear actuator DA that performs position control or load control, for example, such as an electric brake device, the magnitude of the motor angular speed increases temporarily such as panic brake or anti-skid control in the electric brake device. It is considered that it is easy to secure the durability against the heat load of the electric motor 4 because it is in a non-steady state.

<System configuration example>
FIG. 4 is a block diagram showing an example of executing the maximum current adjustment function unit. This will be described together with FIG. FIG. 4 shows an example in which the maximum current limiting function of FIG. 3 is mounted as the maximum current limiter 24a as the maximum current adjusting function unit 24. A load control controller 22a is mounted as the load control function unit 22, and the current command function unit 23 includes a torque → current converter 23c that converts a target motor torque into a current. Further, a current control controller 25a is mounted as the current control function unit 25.

The maximum current limiter 24a and the maximum torque limiter 24b (FIG. 8) described later may be, for example, a look-up table (abbreviated as LUT) of each limit value according to the motor characteristics obtained by analysis or actual measurement in advance. Is preferable because the calculation load can be reduced, but for example, a predetermined calculation formula for calculation based on the motor characteristics such as phase resistance or inductance can also be used.

<About action and effect>
According to the electric linear actuator DA and the electric brake device 1 described above, the current limiting function unit 23a limits the current energized to the electric motor 4 to the maximum current value. The maximum current adjusting function unit 24 determines whether or not the estimated angular velocity is larger than the predetermined angular velocity. When the estimated angular velocity is less than or equal to the specified angular velocity, the specified maximum current value is maintained. The maximum current adjusting function unit 24 temporarily increases the maximum current value when the estimated angular velocity is larger than the predetermined angular velocity. By increasing the maximum current value in the region where the angular velocity of the electric motor 4 is large in this way, the motor output is increased and high-speed response is possible. Therefore, it is possible to reduce the size of the electric motor 4 and perform space-saving and high-output motor control.

<About other embodiments>
In the following description, the same reference numerals will be given to the parts corresponding to the matters described in advance in each embodiment, and duplicate description will be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described above unless otherwise specified. It has the same action and effect from the same configuration. Not only the combinations of the parts specifically described in each embodiment, but also the combinations of the embodiments can be partially combined as long as the combination does not cause any trouble.

As shown in FIG. 5, the control device 2 may include a power supply monitoring function unit 26. The power supply monitoring function unit 26 may, for example, estimate the voltage of the power supply device 3, and if the estimated voltage falls below a predetermined value, it may be determined that the power supply capacity of the power supply device 3 has decreased. Alternatively, the power supply monitoring function unit 26 also estimates the current of the power supply device 3, and can determine that the power supply capacity of the power supply device 3 has decreased when the voltage fluctuation at the time of current output becomes larger than a predetermined value. Alternatively, for example, a higher-level current monitoring function unit (not shown) such as a battery manager that calculates% SOC (State Of Charge), which is a percentage of the state of charge, from the integrated value of the current value of the power supply device 3 is provided to supply power. The monitoring function unit 26 may determine the power supply capacity of the power supply device 3 by communication or the like from the higher-level current monitoring function unit.

Temporarily increasing the maximum output of the electric motor 4 by the maximum current adjusting function unit 24 temporarily increases the maximum load of the power supply device 3. Therefore, in this configuration, when the power supply monitoring function unit 26 is provided and the power supply capacity of the power supply device 3 is reduced, the process of suppressing the increase of the maximum current by the maximum current adjustment function unit 24 or not executing the process is performed. May be preferable from the viewpoint of redundancy. Further, the maximum current can be increased only when the power supply device 3 is normal and has a sufficient power supply capacity. For example, when an abnormality occurs in the power supply device 3, it is possible to prevent the electric linear actuator DA from becoming unusable due to excessive power consumption. Therefore, the redundancy of the electric linear actuator DA can be increased.

As shown in FIG. 6, as a locus for increasing the maximum current as in FIG. 3, the maximum current adjustment function unit 24 sets a linear maximum current locus (straight line locus) Ks whose apex is approximately on the d-axis. You may. Although FIG. 6 shows an example in which the maximum current locus Ks is a straight line with respect to one quadrant, for example, a locus may be provided with a break point as appropriate.
The elliptical locus method of FIG. 3 and the linear locus method of FIG. 6 can be used in combination as appropriate. For example, the maximum current locus may be such that the predetermined region is a straight line and the other predetermined region is an ellipse.

FIG. 7 shows the maximum current adjustment function unit 24 according to the maximum current phase until the magnitude of the angular velocity (| ω |) reaches a predetermined value (| ω | = a) with respect to the example of FIG. An example of increasing the current is shown. Generally, until the magnitude of the motor angular velocity reaches the predetermined value, the current vector control can be performed in the maximum current phase without performing the weakening magnetic flux control. Therefore, as shown in FIG. 7, with respect to the example of FIG. 3, the maximum current adjusting function unit 24 further waits until the magnitude of the angular velocity (| ω |) reaches a predetermined value (| ω | = a). By increasing the maximum current according to the maximum current phase, the effect of temporarily increasing the motor output can be more positively utilized.

In general, current vector control (strengthening magnetic flux control) using a positive d-axis current that strengthens the rotor magnetic flux is not performed, so it is not shown. However, when controlling to increase the positive d-axis current, the control is performed. For example, in the strong magnetic flux region, it may be a conventional perfect circular maximum current, or it may be an ellipse or a straight line.

FIG. 8 is a block diagram showing another system configuration example for executing the maximum current adjustment function unit 24. FIG. 8 shows an example in which the maximum torque limiter 24b that limits the torque according to the magnitude of the motor angular velocity is provided as the maximum current adjusting function unit 24. In this example, by setting a larger maximum torque limit value when the magnitude of the angular velocity increases compared to the case where the maximum current is constant, the current value for exerting torque increases, and as a result. It can be the maximum current locus as shown in any of FIGS. 3, 6 or 7.

As the conversion mechanism portion of the linear motion mechanism 6, various screw mechanisms such as a planetary roller and a ball screw, a mechanism utilizing an inclination such as a ball lamp, and the like can be used.

Although the embodiments for carrying out the present invention have been described above based on the embodiments, the embodiments disclosed this time are exemplary in all respects and are not limiting. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 ... Electric brake device 2 ... Control device 3 ... Power supply device 4 ... Electric motor 6 ... Linear mechanism 8 ... Brake rotor 9 ... Friction material 14 ... Linear unit 20b ... Angle speed estimation function unit 23a ... Current limiting function unit 24 ... Maximum Current adjustment function unit 26 ... Power supply monitoring function unit DA ... Electric linear actuator

Claims (4)

In an electric linear actuator equipped with an electric motor, a linear motion mechanism that converts the rotational motion of the electric motor into a linear motion of a linear motion unit, and a control device that controls the electric motor.
The control device is
An angular velocity estimation function unit that estimates the angular velocity of the electric motor,
A current limiting function unit that limits the current energized to the electric motor to a specified maximum value, and
When the angular velocity estimated by the angular velocity estimation function unit becomes larger than the predetermined angular velocity, the maximum current adjustment function unit that increases the maximum value of the current limited by the current limiting function unit, and the maximum current adjustment function unit.
Have a,
In the control device, when the angular velocity estimated by the angular velocity estimation function unit becomes larger than the defined angular velocity, the estimated angular velocity is determined for the axial current converted as a vector component in the orthogonal axis on the rotating coordinate system. It has a current vector control function that changes the phase of the axial current vector in the direction inverted from the magnetic field vector phase of the rotor in the electric motor as compared with the phase of the axial current vector when the angular velocity is equal to or lower than the angular velocity.
The maximum current adjustment function unit is
Regarding the maximum current locus of the shaft current vector, which is the norm corresponding to the maximum value of the current of the electric motor.
A non-perfect circular ellipse whose longitudinal direction is the vector direction that passes through the point that becomes the maximum current vector that maximizes the torque per current when the estimated angular velocity is approximately zero and that substantially coincides with the magnetic field of the rotor. An electric linear acting actuator that increases the maximum current so that it has a circular trajectory. In an electric linear actuator equipped with an electric motor, a linear motion mechanism that converts the rotational motion of the electric motor into a linear motion of a linear motion unit, and a control device that controls the electric motor.
The control device is
An angular velocity estimation function unit that estimates the angular velocity of the electric motor,
A current limiting function unit that limits the current energized to the electric motor to a specified maximum value, and
When the angular velocity estimated by the angular velocity estimation function unit becomes larger than the predetermined angular velocity, the maximum current adjustment function unit that increases the maximum value of the current limited by the current limiting function unit, and the maximum current adjustment function unit.
Have,
In the control device, when the angular velocity estimated by the angular velocity estimation function unit becomes larger than the defined angular velocity, the estimated angular velocity is determined for the axial current converted as a vector component in the orthogonal axis on the rotating coordinate system. It has a current vector control function that changes the phase of the axial current vector in the direction inverted from the magnetic field vector phase of the rotor in the electric motor as compared with the phase of the axial current vector when the angular velocity is equal to or lower than the angular velocity.
The maximum current adjustment function unit is
Regarding the maximum current locus of the shaft current vector, which is the norm corresponding to the maximum value of the current of the electric motor.
When the estimated angular velocity is substantially zero, the linear locus passes through the point where the torque per current becomes the maximum current vector, and the vector direction substantially coincides with the magnetic field of the rotor is used as the apex. An electric linear actuator that increases the maximum current. In the electric linear motion actuator according to claim 1 or 2 , the control device uses either or both of the voltage and the current of the power supply device that supplies electric power for driving the electric motor. It has a power supply monitoring function unit that determines the power supply capacity of the power supply device, and the maximum current adjustment function unit determines the maximum value of the current when the power supply capacity determined by the power supply monitoring function unit is higher than a predetermined value. Electric linear acting actuator to increase. The electric linear actuator according to any one of claims 1 to 3, the friction material operated by the electric linear motion actuator, and the brake rotor that generates a braking force by contact with the friction material. And, equipped with an electric brake device.

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