Control device for motor and parking lock device

Abstract

To provide a control device for a motor and a parking lock device that are designed so that not only the angular position of a rotor quickly reaches a target angular position, but also the stop position of the rotor is highly accurate.SOLUTION: A control device 1 for a motor 100 includes: a position determination unit 40 that determines whether an angular position x of a rotor 104 obtained from a detection signal of a Hall element H has reached a target angular position x* of the rotor 104 or not; and a control mode switching unit 50 that switches a control mode between a feedback control mode and a stop control mode, the feedback control mode being for performing energization control on coils of a pair of phases corresponding to the angular position x among three phase coils 101 by an output determined by feedback control based on a deviation Δx between the angular position x and the target angular position x*, the stop control mode being for performing energization control on a final energization coil that has energized last in the feedback control mode among the three phase coils 101. When the position determination unit 40 determines that the angular position x has reached the target angular position x*, the control mode switching unit 50 switches the control mode from the feedback control mode to the stop control mode.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a motor control device and a parking lock device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known a control device for a three-phase motor that controls the three-phase motor based on detection signals of Hall elements.

[0003] For example, Patent Document 1 describes a device that controls a three-phase DC motor based on a signal obtained by converting the output signal of a Hall IC using a pre-prepared table when it is determined that adjustment of the rotation stop position should be started based on the rotation speed of the three-phase DC motor and the number of pulses remaining until the rotation stops. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-43912 Summary of the Invention [Problem to be solved by the invention]

[0005] Depending on the purpose of the motor, position feedback control may be desirable, in which the motor is controlled with an output determined based on the deviation (position deviation) between the rotor's angular position obtained from the detection signal of the Hall element and a target angular position. For example, since a parking lock device needs to quickly move a parking lock pole between a locked position, in which the axle is locked, and an unlocked position, in which the axle is released, it is desirable to control the motor (parking lock actuator) using position feedback control.

[0006] However, when the rotor is stopped at a target angular position by position feedback control, even if the angular position of the rotor reaches the target angular position and the position deviation becomes zero, if an external force acts on the output shaft of the motor, the angular position of the rotor will pass the target angular position. For example, if a reducer is connected to the output shaft of the motor, an external force may act on the rotor via the output shaft of the motor from the gear of the reducer, which continues to rotate due to inertia. In this case, unless the rotor rotates further and a detection signal from the Hall element indicating a new angular position is received, correction of the rotor stopping position in the feedback control mode cannot be expected, and the accuracy of the rotor stopping position will decrease.

[0007] In addition, in normal mode, the control device described in Patent Document 1 outputs a PWM signal corresponding to the speed specified by the microcomputer (before braking begins) or a fixed PWM signal for braking (after braking begins) to the motor driver, and does not perform feedback position control.

[0008] In view of the above-mentioned circumstances, at least some embodiments of the present invention aim to provide a motor control device and a parking lock device that can achieve both rapid achievement of a rotor angular position to a target angular position and high accuracy in the stopping position of the rotor. [Means for solving the problem]

[0009] A motor control device according to at least some embodiments of the present invention includes: A control device for a motor including a stator including a three-phase coil, a rotor including a magnet arranged opposite to the stator, and a Hall element for generating a detection signal indicating an angular position of the rotor, a position determination unit for determining whether or not the angular position of the rotor obtained from the detection signal of the Hall element has reached a target angular position of the rotor; a control mode switching unit configured to switch between a feedback control mode in which energization control is performed on a pair of coils of a phase corresponding to the angular position of the three-phase coils, based on an output determined by feedback control based on a deviation between the angular position of the rotor obtained from a detection signal of the Hall element and a target angular position, and a stop control mode in which energization control is performed on a final energized coil that was last energized in the feedback control mode, among the three-phase coils; Equipped with The control mode switching unit is configured to switch the control mode from the feedback control mode to the stop control mode when the position determination unit determines that the angular position has reached the target angular position. Effect of the Invention

[0010] In at least some embodiments of the present invention, the control mode switching unit operates to switch from the feedback control mode to the stop control mode when the rotor reaches the target angular position, and energization control is performed on the coil that was last energized in the feedback control mode (the last energized coil). Therefore, even if the rotor passes the target angular position, a torque suitable for returning the rotor to the target angular position can be applied to the rotor, regardless of whether or not the next detection signal from the Hall element indicating the new angular position of the rotor is received, thereby achieving high accuracy in the stop position of the rotor. Therefore, the feedback control mode and the stop control mode make it possible to quickly bring the angular position of the rotor to the target angular position while improving the accuracy of the stopping position of the rotor. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a hardware configuration diagram of a motor control device according to an embodiment. [Diagram 2] 1 is a schematic diagram illustrating a configuration of a motor according to an embodiment. [Figure 3A] FIG. 1 is a schematic diagram showing a configuration of a parking lock device according to an embodiment, illustrating an unlocked state of the parking lock device. [Figure 3B]FIG. 1 is a schematic diagram showing a configuration of a parking lock device according to an embodiment, illustrating a locked state of the parking lock device. [Figure 4] FIG. 2 is a functional block diagram of a control device according to an embodiment. [Diagram 5] FIG. 4 is a schematic diagram showing a transition of a current supply pattern of a three-phase coil according to one embodiment. [Figure 6] 4 is a timing chart showing an example of a detection signal of a Hall element according to an embodiment. [Figure 7] 5 is a timing chart illustrating an example of an operation of a control device according to an embodiment. [Figure 8] 4 is a flowchart showing a control flow of a control device in one embodiment. [Figure 9] FIG. 11 is a functional block diagram of a control device according to another embodiment. [Figure 10A] 11A and 11B are diagrams illustrating an example of a current supply pattern in a stop control mode. [Figure 10B] 13A and 13B are diagrams illustrating an example of a current supply pattern in a high-precision stop control mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the contents described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0013] Fig. 1 is a hardware configuration diagram of a motor control device according to an embodiment of the present invention, and Fig. 2 is a schematic diagram showing the configuration of a motor according to an embodiment of the present invention.

[0014] In some embodiments, as shown in FIG. 1, the control device 1 of the motor 100 includes a processor 2 for processing information obtained from external devices (such as a higher-level controller 3 or a Hall element H described below) and calculating control commands for controlling the motor 100. The processor 2 may be a microcontroller (MCU: Micro Controller Unit) or a central processing unit (CPU: Central Processing Unit) of a microcomputer.

[0015] The control device 1 has a storage unit 4 including a RAM (Random Access Memory) and a ROM (Read Only Memory) as hardware related to the processor 2. The ROM of the storage unit 4 stores programs executed by the processor 2 and information necessary for the processing of the processor 2. The RAM of the storage unit 4 is used for reading and writing temporary data while the processor 2 is executing a program. The storage unit 4 may be a RAM or ROM built into a microcontroller or a microcomputer.

[0016] 1, the control device 1 includes a communication circuit 6 that handles communication between the processor 2 and the upper controller 3. The processor 2 acquires a target position of the motor 100 from the upper controller 3 via the communication circuit 6, and uses the target position to generate a control command. The details of the calculation function of the processor 2 for the control command will be described later.

[0017] In some embodiments, the control device 1 provides a switching control signal as a control command to the inverter 120 for energizing the coil (motor coil) of the motor 100. The inverter 120 has multiple switching elements, and switches each switching element between ON and OFF in accordance with a switching control signal from the control device 1. The switching control signal may be a pulse width modulation (PWM) signal that adjusts the duty ratio by changing the proportion of the ON time while keeping the switching period constant. In this way, the motor 100 is driven under the control of the control device 1 by controlling the power supplied to the motor coil by the inverter 120 in accordance with the switching control signal.

[0018] In some embodiments, the motor 100 controlled by the control device 1 is a brushless DC motor driven by a direct current. 2 is a brushless DC motor including a stator 102 having three-phase coils 101 (101U, 101V, 101W) and a rotor 104 having magnets 103 (103A, 103B) arranged opposite to the stator 102. The magnets 103 are permanent magnets.

[0019] In the exemplary embodiment shown in FIG. 2, the motor 100 has a two-pole, three-slot configuration including a magnet 103 composed of a pair of N pole 103A and S pole 103B, and a three-phase coil 101 composed of three coils (101U to 101W) for U phase, V phase, and W phase. However, in the present invention, there is no particular limitation on the number of pole pairs of the magnet 103 or the number of coils of the three-phase coil 101. In other embodiments, the motor 100 has any configuration, such as 4 poles and 6 slots, 6 poles and 9 slots, 8 poles and 9 slots, or 10 poles and 12 slots.

[0020] In the exemplary embodiment shown in FIG. 2, the motor 100 is an inner rotor type motor in which a rotor 104 rotates radially inside a stator 102 . In another embodiment, the motor 100 is an outer rotor type motor in which the rotor 104 rotates radially outside the stator 102 .

[0021] 1 and 2, the motor 100 includes a Hall element H that generates a detection signal indicative of the rotor angular position of the motor 100. The detection signal of the Hall element H is processed by the processor 2 of the control device 1 and used to generate a control command. Although three Hall elements H (H1 to H3) are shown in FIG. 1 and FIG. 2, the number of Hall elements H is not limited to this example.

[0022] 2, a plurality of Hall elements H (H1 to H3) are disposed at equal intervals in the circumferential direction and radially adjacent to the magnet 103 of the rotor 104. In this case, the Hall elements H (H1 to H3) detect the magnetic field generated by the magnet 103 of the rotor 104 to obtain a detection signal indicating the angular position of the rotor 104. In some other embodiments, the Hall element H is disposed in proximity to another magnet that rotates together with the rotor 104 of the motor 100. In this case, the Hall element H detects a magnetic field generated by the other magnet different from the magnet 103 of the rotor 104 to obtain a detection signal indicative of the angular position of the rotor 104.

[0023] 1, an output shaft of a motor 100, which is an object to be controlled by the control device 1, is connected to a driven device 200 via a reducer 130. The driven device 200 receives power from the motor 100 via the reducer 130 and is driven. In another embodiment, the driven device 200 receives power directly from the motor 100 without going through the reducer 130. In this case, the driven device 200 may include a speed change mechanism therein.

[0024] The motor 100 that operates under the control of the control device 1 having the above configuration can be applied as an actuator for any driven device 200. For example, the motor 100 may be an actuator for a parking lock device mounted on a vehicle.

[0025] 3A and 3B are schematic diagrams showing a configuration of a parking lock device according to one embodiment, where FIG. 3A shows the parking lock device in an unlocked state and FIG. 3B shows the parking lock device in a locked state.

[0026] In some embodiments, as shown in FIGS. 3A and 3B, the parking lock device 200A includes a parking lock gear 210 and a parking lock pole 220 engageable with the parking lock gear 210. The parking lock gear 210 is connected to an axle of a vehicle (not shown). The parking lock gear 210 may be directly fixed to the axle, or may be indirectly fixed to the axle via another member. The parking lock pole 220 has a protrusion 222 at its tip that can engage with the teeth 212 of the parking lock gear 210. The parking lock pole 220 is provided rotatably around a support shaft 224, and is biased by a biasing member 226 in a direction in which the protrusion 222 moves away from the parking lock gear 210. The biasing member 226 may be a spring.

[0027] The parking lock pole 220 is configured to be movable between an unlocked position (FIG. 3A) in which it is disengaged from the parking lock gear 210 and a locked position (FIG. 3B) in which it is engaged with the parking lock gear 210 by power from the motor 100 operating under the control of the control device 1. Specifically, in the unlocked position, the projection 222 of the parking lock pole 220 is retracted from the teeth 212 of the parking lock gear 210, and the axle is unlocked by the parking lock device 200A. When the parking lock pole 220 receives the power of the motor 100 in the unlocked position, it rotates around the support shaft 224 in the direction of the arrow in FIG. 3A against the biasing force of the biasing member 226. As a result, the parking lock pole 220 reaches the locked position shown in FIG. 3B, and the projection 222 of the parking lock pole 220 engages with the teeth 212 of the parking lock gear 210. In this way, the axle is locked by the parking lock device 200A. When the parking lock pole 220 receives the power of the motor 100 in the locked position, it rotates around the support shaft 224 in the direction of the arrow in FIG. 3B, and can return to the unlocked position shown in FIG. 3A.

[0028] In some embodiments, the parking lock device 200A further includes one or more power transmission members (230, 240) for transmitting the power of the motor 100 to the parking lock pole 220. In the exemplary embodiment shown in Figures 3A and 3B, the power transmission members (230, 240) include a parking lock lever 230 that rotates by power from the motor 100, and a parking lock rod 240 that is provided between the parking lock lever 230 and the parking lock pole 220.

[0029] The parking lock lever 230 includes a detent shaft 232 connected to the output shaft of the motor 100 (or, in the case of a motor 100 with a reducer 130, the output shaft of the reducer 130) and a pair of recesses (234A, 234B) with which a stopper 236 can engage. Of the pair of recesses (234A, 234B), the first recess 234A is a recess with which the stopper 236 engages when the parking lock pole 220 is in the unlocked position shown in Fig. 3A. In contrast, the second recess 234B is a recess with which the stopper 236 engages when the parking lock pole 220 is in the locked position shown in Fig. 3B. The stopper 236 is biased toward the parking lock lever 230 by a biasing member 237, which may be a spring. Therefore, when the parking lock lever 230 rotates by the power of the motor 100 input to the detent shaft 232, the stopper 236 moves between the pair of recesses (234A, 234B) while maintaining a contact state with the parking lock lever 230. Specifically, the stopper 236 engaged with the first recess 234A at the unlocked position of the parking lock pole 220 shown in FIG. 3A moves relatively toward the second recess 234B along the outer edge of the parking lock lever 230 as the parking lock lever 230 rotates clockwise. On the other hand, the stopper 236 engaged with the second recess 234B at the locked position of the parking lock pole 220 shown in FIG. 3B moves relatively toward the first recess 234A along the outer edge of the parking lock lever 230 as the parking lock lever 230 rotates counterclockwise.

[0030] The parking lock rod 240 is attached to a portion of the parking lock lever 230 opposite the pair of recesses (234A, 234B) across the detent shaft 232. The parking lock rod 240 is attached to the parking lock lever 230 so as to be rotatable around a rotation shaft 241. The parking lock rod 240 is guided by a guide member (not shown) so as to move forward or backward in the axial direction of the parking lock rod 240. For this reason, when the parking lock lever 230 rotates clockwise with the parking lock pole 220 in the unlocked position shown in Fig. 3A, the parking lock rod 240 moves forward in the axial direction toward the parking lock pole 220. In contrast, when the parking lock lever 230 rotates counterclockwise with the parking lock pole 220 in the locked position shown in Fig. 3B, the parking lock rod 240 moves backward in the axial direction away from the parking lock pole 220.

[0031] The parking lock rod 240 has a tapered portion 242 at an end opposite to the end connected to the parking lock lever 230. On the other hand, the parking lock pole 220 has an engaging portion 228 located at an end opposite to the projection 222 (the base end side of the parking lock pole 220) across the support shaft 224, and the engaging portion 228 of the parking lock pole 220 is adapted to engage with the tapered portion 242 of the parking lock rod 240. Therefore, as the parking lock rod 240 advances, the engagement position of the engaging portion 228 with respect to the tapered portion 242 shifts toward the base end side of the tapered portion 242, and the parking lock pole 220 rotates counterclockwise (see the arrow in FIG. 3A). In contrast, when the parking lock rod 240 retracts, the engagement position of the engagement portion 228 with the tapered portion 242 shifts toward the tip side of the tapered portion 242, and the parking lock pole 220 rotates clockwise (see the arrow in FIG. 3B). Since the parking lock pole 220 is biased by the biasing member 226 in a direction away from the parking lock gear 210, contact between the engagement portion 228 and the tapered portion 242 is maintained even when the parking lock rod 240 is in the retracted position shown in FIG. 3A.

[0032] Next, the control command generating function in the control device 1 will be described with reference to FIG. Fig. 4 is a functional block diagram of the control device 1 according to an embodiment. Note that the functions of the control device 1 shown in Fig. 4 are realized by the hardware configuration (the processor 2 and the storage unit 4) of the control device 1 described above with reference to Fig. 1. In this specification, when distinguishing the control device 1 of the embodiment shown in FIG. 4 from the control device 1 of the embodiment shown in FIG. 9 described later, the former may be referred to as a control device 1A and the latter as a control device 1B.

[0033] In some embodiments, as shown in Fig. 4, the control device 1 includes a position feedback unit 10 that is responsible for the feedback control mode and a stop control unit 20 that is responsible for the stop control mode. The control device 1 can selectively execute either the feedback control mode or the stop control mode.

[0034] The position feedback unit 10 generates a control command for controlling energization of the motor coil with an output determined based on a deviation Δx between an angular position x of the rotor 104 obtained from detection signals of the Hall elements H (H1 to H3) and a target angular position x*. Specifically, the position feedback unit 10 calculates a duty ratio that enables energization control with the output determined based on the deviation Δx, and generates a switching control signal corresponding to this duty ratio. The switching control signal may be a PWM control signal as described above. When determining the output (or duty ratio) based on the deviation Δx (=x*-x), calculations based on P control, PI control, or PID control may be performed. Here, P control calculates a command value from a proportional term proportional to the deviation Δx. PI control calculates a command value taking into account the integral term of the deviation Δx in addition to the proportional term of the deviation Δx. PID control calculates a command value taking into account the proportional term of the deviation Δx, the integral term of the deviation Δx, and the differential term of the deviation Δx.

[0035] The target angular position x* of the rotor 104 used in the calculation by the position feedback unit 10 may be input to the processor 2 from the higher-level controller 3 described with reference to FIG.

[0036] During execution of the feedback control mode by the position feedback unit 10, the angular position x of the rotor 104 of the motor 100 changes over time until it reaches a target angular position x*. For this reason, it is necessary to appropriately select the coils to be energized among the three-phase coils 101 (101U to 101W) of the motor 100 according to the angular position x of the rotor 104.

[0037] With reference to FIG. 5, the transition of the current supply pattern of the three-phase coil 101 in response to the change in the angular position x of the rotor 104 will be described. Fig. 5 is a schematic diagram showing a transition of a current supply pattern of a three-phase coil 101 according to one embodiment. The arrows shown on a pair of coils to be energized among the three-phase coils 101 in Fig. 5 indicate the direction of magnetic flux generated by the coils to be energized. The notation of 0 deg to 300 deg in FIG. 5 indicates the electrical angle of the motor 100 in each state. Note that FIG. 5 shows the coil current conduction pattern for the 2-pole, 3-slot motor 100 shown in FIG. 2, and the electrical angle and the mechanical angle are the same. In contrast, in the motor 100 of another structure, the electrical angle may differ from the mechanical angle. For example, in the case of the 4-pole, 6-slot motor 100, the three-phase coils are arranged in the order of 101U, 101V, 101W, 101U, 101V, 101V, 101W at 60 degree intervals in the circumferential direction, and the electrical angle changes by two periods (720 deg) while the rotor 104 rotates once (mechanical angle 0 deg to 360 deg). Note that even in the case of the motor 100 of a structure other than the 2-pole, 3-slot structure, the current conduction pattern in each state of the electrical angle 0 deg to 300 deg is the same as that of the 2-pole, 3-slot structure shown in FIG. 5.

[0038] 5, when a current flows from the W-phase (101W) to the V-phase (101V) (W→V) at an electrical angle of 0 deg, the W-phase coil 101W generates a magnetic flux that flows radially inward, and the V-phase coil 101V generates a magnetic flux that flows radially outward, as shown in FIG. 5. The resultant magnetic flux of these magnetic fluxes applies a torque to the magnet 103 at an angular position corresponding to an electrical angle of 0 deg, which rotates the rotor 104 clockwise. When the angular position x of the rotor 104 changes and the electrical angle reaches 60 degrees, the current pattern is switched to (U→V) in which current flows from the U phase (101U) to the V phase (101V). As a result, the U-phase coil 101U generates a magnetic flux that flows radially inward, and the V-phase coil 101V generates a magnetic flux that flows radially outward. The composite magnetic flux of these magnetic fluxes applies a torque to the magnet 103 at an angular position corresponding to an electrical angle of 60 degrees, which rotates the rotor 104 clockwise. Similarly, the U→W conduction pattern is selected at an electrical angle of 120 degrees, the V→W conduction pattern is selected at an electrical angle of 180 degrees, the V→U conduction pattern is selected at an electrical angle of 240 degrees, and the W→U conduction pattern is selected at an electrical angle of 300 degrees. Note that the conduction pattern after W→U is the W→V conduction pattern, which is selected again after returning to an electrical angle of 0 degrees.

[0039] As described above, the position feedback section 10 determines the output (or duty ratio) based on the deviation Δx, and selects the current conduction pattern according to the angular position x of the rotor 104, thereby generating a control command in the feedback control mode.

[0040] In response to this, the stop control unit 20 generates a control command in the stop control mode for controlling energization of the final energized coil that was last energized in the feedback control mode. That is, the stop control unit 20 generates a control command for controlling energization of the final energized coil in accordance with the last energization pattern (final energization pattern) in the feedback control mode. 4, in some embodiments, the stop control unit 20 receives information about the last energized coil from the position feedback unit 10 while the control device 1 is executing the feedback control mode. The stop control unit 20 always holds the latest information about the last energized coil, thereby preparing for switching from the feedback control mode to the stop control mode. At this time, the stop control unit 20 may temporarily store the information about the last energized coil in the RAM of the storage unit 4, and constantly update the information about the last energized coil temporarily stored in the RAM to the latest value. In another embodiment, the stop control unit 20 acquires information regarding the final energized coil from the position feedback unit 10 only when the angular position x of the rotor 104 reaches an electrical angle immediately before the target angular position x* among the electrical angles (0 deg, 60 deg, 120 deg, 180 deg, 240 deg, and 300 deg in the example shown in FIG. 5 ) corresponding to the timing of switching the energization pattern.

[0041] The specific control command generating function of the stop control unit 20 may take various forms. For example, with regard to the timing of starting energization of the final energized coil in the stop control mode, in one embodiment, the stop control unit 20 starts energization control of the final energized coil immediately after transition to the stop control mode. In another embodiment, the stop control unit 20 starts energization control of the final energized coil when a first specified time has elapsed since the angular position x of the rotor 104 obtained from the detection signal of the Hall element H reaches the target angular position x*. Moreover, with regard to the energization duration in the stop control mode, in one embodiment, the stop control unit 20 continues the energization control for the last energized coil for a predetermined time (a second specified time). Furthermore, with regard to the duty ratio in the stop control mode, in one embodiment, the stop control unit 20 may control the energization of the final energized coil by PWM control based on a fixed duty ratio (second duty ratio), in contrast to the feedback control mode. Note that the second duty ratio is a specified value stored in the ROM of the storage unit 4, and the stop control unit 20 may obtain the second duty ratio from the storage unit 4. The above-mentioned aspect of the control command generating function in the stop control unit 20 will be described in detail later with reference to FIG.

[0042] In some embodiments, the control device 1 further includes, in addition to the above-mentioned position feedback unit 10 and stop control unit 20, an angular position acquisition unit 30 that acquires the angular position x of the rotor 104, a position determination unit 40 that determines the angular position of the rotor 104, and a control mode switching unit 50 for switching the control mode.

[0043] The angular position acquisition unit 30 acquires the angular position x of the rotor 104 from the detection signals of the Hall elements H (H1 to H3).

[0044] 6 is a timing chart showing an example of a detection signal of the Hall element H according to an embodiment. The horizontal axis of FIG. 6 represents an electrical angle, and the energization patterns refer to six types of energization patterns for the three-phase coils 101 (101U to 101W) shown in FIG.

[0045] The detection signal level (Hi or Lo) of each of the Hall elements H1 to H3 varies with the change in the angular position x of the rotor 104. Here, with regard to the detection signal level of each Hall element H, Hi is a detection of the magnetic field generated by the N pole 103A of the magnet 103, and Lo is a detection of the magnetic field generated by the S pole 103B of the magnet 103.

[0046] 6, there are six combinations of detection signal levels Hi and Lo of each of the Hall elements H1 to H3. The angular position acquisition unit 30 acquires the angular position x of the rotor 104 based on which of the six combinations of detection signal levels Hi and Lo of each of the Hall elements H1 to H3 is. In this case, the angular position acquisition unit 30 may acquire information on the angular position x of the rotor 104 corresponding to each combination of detection signal levels Hi and Lo of the Hall elements H1 to H3 from the ROM of the storage unit 4. Since the number of combinations of the detection signal levels Hi and Lo of the Hall elements H1 to H3 is finite, the angular position x that can be acquired by the angular position acquisition unit 30 is discrete. For example, in the example shown in Fig. 6, there are six combinations of the detection signal levels Hi and Lo of the Hall elements H1 to H3, and the angular position acquisition unit 30 can acquire the angular position x every 60 degrees.

[0047] The angular position x of the rotor 104 acquired by the angular position acquisition unit 30 is sent to the position feedback unit 10 and the position determination unit 40, and is used to generate a control command based on the deviation Δx in the feedback control mode, to determine the current conduction pattern, and to switch the control mode.

[0048] The position determination unit 40 compares the angular position x of the rotor 104 acquired by the angular position acquisition unit 30 from the detection signals of the Hall elements H (H1 to H3) with the target angular position x*, and determines whether the angular position x of the rotor 104 has reached the target angular position x*. The comparison of the angular position x of the rotor 104 with the target angular position x* in the position determination unit 40 may also serve as a function of calculating the deviation Δx (=x*-x) in the position feedback unit 10. In this case, the position determination of the position determination unit 40 is performed by determining whether the value of the deviation Δx calculated in the position feedback unit 10 is zero or not.

[0049] The control mode switching unit 50 selects either the feedback control mode or the stop control mode as the control mode of the control device 1 based on the determination result of the position determination unit 40. Specifically, the control mode switching unit 50 selects the feedback control mode when the angular position x of the rotor 104 has not reached the target angular position x*, and selects the stop control mode when the angular position x of the rotor 104 reaches the target angular position x*.

[0050] 4, the control mode switching unit 50 receives a control command for the feedback control mode from the position feedback unit 10 and receives a control command for the stop control mode from the stop control unit 20, and switches the control mode by selecting one of the control commands based on the determination result of the position determination unit 40. That is, the control mode switching unit 50 selects either the control command generated by the position feedback unit 10 or the control command generated by the stop control unit 20, and outputs the selected control command to the inverter 120. In another embodiment, the control mode switching unit 50 first selects a control mode based on the determination result of the position determination unit 40, and causes either the position feedback unit 10 or the stop control unit 20 to generate a control command corresponding to the selected control mode. The position feedback unit 10 and the stop control unit 20 each generate a control command in response to a request from the control mode switching unit 50, and this control command is input to the inverter 120 as an output signal from the control device 1.

[0051] 4, the control device 1 further includes a limiter 64 that limits the duty ratio of the control command output from the control device 1. The control device 1 also includes a current detection unit 62 that detects the motor current based on a detection signal from a current sensor 60 for detecting the motor current and determines whether or not an overcurrent exists. The limiter 64 switches between limiting and not limiting the duty ratio based on the determination result of the current detection unit 62. In this way, the current detector 62 and the limiter 64 function to prevent an excessive current from flowing through the three-phase coils 101 (101U to 101W) of the motor 100.

[0052] Fig. 7 is a timing chart showing an example of the operation of the control device 1 according to an embodiment. Fig. 7 is an example of the timing chart, and the operation of the control device 1 is not limited to this example. 7, three positions xH_0 to xH_2 for the angular position x of the rotor 104 indicate discrete angular positions acquired from the detection signal of the Hall element H at times t0 to t2, respectively. Among these, position xH_2 is the angular position of the rotor 104 acquired from the detection signal of the Hall element H when the angular position x of the rotor 104 reaches the target angular position x* at time t=t2, where xH_2=x*. Moreover, position xH_3 shown in FIG. 7 is the next position after position xH_2 among the discrete angular positions that can be acquired from the detection signal of the Hall element H.

[0053] 7, the control device 1 executes control in a feedback control mode during a period (0≦t≦t2) until the angular position x of the rotor 104 reaches a target angular position x* (=xH_2). In the feedback control mode, PWM control is performed based on a variable duty ratio (first duty ratio) determined according to a deviation Δx between the angular position x of the rotor 104 and the target angular position x*. The PWM control signal based on the first duty ratio is generated in the position feedback unit 10 of the control device 1. In the example shown in Fig. 7, immediately after the start of the motor 100 at t=0, the first duty ratio is limited by a soft start function for suppressing inrush current. After the start of the motor 100, the first duty ratio gradually increases over time. When the control device 1 includes the limiter 64, the first duty ratio is limited to be equal to or less than the limit value D_lim shown in Fig. 7. When the deviation Δx becomes smaller, the first duty ratio decreases.

[0054] While the control device 1 is executing the feedback control mode, the angular position x of the rotor 104 is acquired by the angular position acquisition unit 30 from the detection signal of the Hall element H (H1 to H3) according to the principle described above with reference to FIG. 6, and is sent to the position feedback unit 10 for use in calculating the deviation Δx. As described above, the angular position x of the rotor 104 acquired by the angular position acquisition unit 30 is updated to a new position at the timing when the combination of the detection signal levels Hi and Lo of the Hall elements H (H1 to H3) switches. Therefore, even if the angular position x of the rotor 104 actually changes continuously, the angular positions detected based on the detection signals of the Hall elements H (H1 to H3) are discrete, such as xH_0 to xH_4 in FIG. 7.

[0055] While the control device 1 is executing the feedback control mode, as described with reference to FIG. 5, the coils to be energized and the energization direction are selected from the three-phase coils 110 (110U to 110W) according to the angular position x of the rotor 104. In the example shown in FIG. 7, current is passed through the U phase and then the V phase in accordance with the angular position xH_0 of the rotor 104 at t=t0 (angle position of 60 deg in FIG. 5) (current passing pattern "U→V"), and then current is passed through the U phase and then the W phase in accordance with the angular position xH_1 of the rotor 104 at t=t1 (angle position of 120 deg in FIG. 5) (current passing pattern "U→W").

[0056] In the feedback control mode, current supply to the coil is controlled with an output (first duty ratio) determined by feedback control based on the deviation Δx between the angular position x of the rotor 104 and a target angular position x*. The feedback control mode is advantageous over control with a fixed duty ratio in that it can quickly bring the angular position x of the rotor 104 close to the target angular position x*. 7, in a period in which the deviation Δx is large after the start of the motor 100, the first duty ratio is set to a relatively large value, and as a result, the rotation speed of the rotor 104 increases rapidly immediately after the start of the motor 100. This shortens the time it takes for the angular position x of the rotor 104 to reach the target angular position x*.

[0057] On the other hand, since the feedback control mode requires the deviation Δx to generate a control command, if the angular position x of the rotor 104 passes the target angular position x*, correction of the rotor position by the feedback control mode cannot be expected unless the rotor 104 rotates further and a detection signal from the Hall element H indicating a new angular position (xH_3 in the example of FIG. 7) is received.

[0058] Therefore, as shown in FIG. 7, the control device 1 transitions from the feedback control mode to the stop control mode by the operation of the control mode switching unit 50 when the angular position x of the rotor 104 reaches the target angular position x*(xH_2). As described above, the stop control mode controls energization of the final energized coil that was last energized in the feedback control mode, and a control command in the stop control mode is generated by the stop control unit 20. In the example shown in Fig. 7, the final energization pattern is "U→W" from t=t1 to t2, and the U-phase coil 101U and the W-phase coil 101W are the final energized coils. Therefore, in the example shown in Fig. 7, the control device 1 executes the stop control mode in which energization control of the coils is performed with the final energization pattern of "U→W" from t=t3 to t4.

[0059] 7, the control device 1 starts, as a stop control mode, energization control for the final energized coil at time t=t3 after a first specified time has elapsed from the time (t=t2) when the angular position x of the rotor 104 obtained from the detection signal of the Hall element H reaches the target angular position x*. In this example, the first specified time is t3-t2. In the example shown in FIG. 7, the energization control for the final energized coil in the stop control mode continues for a second specified time (=t4-t3).

[0060] In the embodiment shown in FIG. 7, in contrast to the feedback control mode in which PWM control is performed based on a variable first duty ratio according to the deviation Δx, the stop control unit 20 controls the energization of the final energized coil by PWM control based on a fixed duty ratio D_fix (second duty ratio).

[0061] FIG. 8 is a flowchart showing a control flow of the control device 1 in one embodiment. As shown in the figure, in the control device 1, the angular position acquisition unit 30 acquires the angular position x of the rotor 104 from the detection signal of the Hall element H (S10), and the position determination unit 40 determines whether the angular position x has reached the target angular position x* (S12). If the angular position x of the rotor 104 has not reached the target angular position x* (N in S12), the feedback control mode is selected by the control mode switching unit 50. The position feedback unit 10 calculates a deviation Δx between the angular position x of the rotor 104 and the target angular position x* (S14), calculates a first duty ratio based on the deviation Δx (S16), and generates a PWM control signal based on this first duty ratio as a control command in the feedback control mode. When the feedback control mode is selected by the control mode switching unit 50, the PWM control signal based on the first duty ratio obtained by the position feedback unit 10 is output to the inverter 120 as a control command from the control device 1 (S18). Thereafter, the process returns to S10, and the angular position x of the rotor 104 is acquired. When the angular position x of the rotor 104 reaches the target angular position x* (Y in S12), the control mode switching unit 50 switches the control mode of the control device 1 from the feedback control mode to the stop control mode (S20). In the stop control mode, the control device 1 outputs a control command generated by the stop control unit 20. The stop control unit 20 specifies the last energized coil that is the target of energization control in the last energization pattern in the feedback control mode (S22), and obtains a second duty ratio that is a fixed value (S24). The stop control unit 20 determines whether a first specified time has elapsed since the angular position x of the rotor 104 reaches the target angular position x* (S26), and if the first specified time has elapsed (Y in S26), generates a PWM control signal based on the second duty ratio for energizing the last energized coil. Then, this PWM control signal is output to the inverter 120 as a control command in the stop control mode from the control device 1 (S28). The stop control unit 20 determines whether or not a second specified time has elapsed since the start of the energization control for the last energized coil (S30), and continues to execute S28 until the second specified time has elapsed.

[0062] Next, a control device 1B according to another embodiment different from the control device 1A shown in FIG. 4 will be described with reference to FIG. 9 is a functional block diagram of a control device 1B according to another embodiment. The control device 1B shown in the figure differs from the control device 1A in that it further includes a high-precision stop control unit 70. The high-precision stop control unit 70 generates a control command in a high-precision stop control mode in which current is applied to the three-phase coils 101 (101U to 101W) in a current application pattern preset in accordance with the target angular position x*. The high-precision stop control unit 70 may obtain the current application pattern stored in the ROM of the storage unit 4 and generate a control command in the high-precision stop control mode.

[0063] In one embodiment, the control device 1 starts outputting a control command in the high accuracy stop control mode to the inverter 120 immediately after the end of the energization control according to the final energization pattern in the stop control mode. In addition, the duty ratio and duration of the power supply control in the high-precision stop control mode may each be a fixed value determined in advance.

[0064] Hereinafter, the energization pattern in the high-precision stop control mode will be described while comparing it with the stop control mode executed in the period from time t2 to t4 in the timing chart shown in FIG. Fig. 10A is a diagram showing an example of a current conduction pattern in the stop control mode, and shows the case where the current conduction pattern in the stop control mode is "U → W" in accordance with the example shown in Fig. 7. Fig. 10B is a diagram showing an example of a current conduction pattern in the high-precision stop control mode. In Fig. 10A and Fig. 10B, the rotor 104 is shown in a balanced position corresponding to the composite magnetic flux of each current conduction pattern. 10A and 10B, the target angular position x* of the rotor 104 is the angular position x where the boundary between the N pole 103A and the S pole 103B is horizontal and the N pole 103A is located below the S pole 103B. In this case, the target angular position x* corresponds to the angular position x of the rotor 104 in the case of an electrical angle of 180 deg in FIG.

[0065] As described above, the control device 1 performs control in the feedback control mode with the energization pattern shown in FIG. 5 until the angular position x of the rotor 104 reaches the target angular position x* (corresponding to an electrical angle of 180 deg), and switches to the stop control mode when the angular position x reaches the target angular position x*. At this time, in the stop control mode, energization control is performed with the "U→W" energization pattern as the final energization pattern in the feedback control mode, as shown in FIG. 10A. The composite magnetic flux 105A of the magnetic fluxes generated by the U-phase coil 101U and the W-phase coil 101W respectively brings the rotor 104, which has passed the target angular position x*, closer to the target angular position x*. However, the balanced position of the rotor 104 when the composite magnetic flux 105A acts is slightly shifted from the target angular position x*, as shown in FIG. 10A.

[0066] In this regard, in the high-precision stop control mode executed after the stop control mode, current control is performed in the "U→VW" current pattern as shown in Fig. 10B, so that the balanced position when the composite magnetic flux 105B of the three-phase coil 101 acts on the rotor 104 substantially coincides with the target angular position x*. Therefore, the rotor 104 can be stopped at the target angular position x* with higher precision. The "U→VW" current pattern is a current pattern in which the current flowing through U-phase coil 101U is divided in half and supplied to V-phase coil 101V and W-phase coil 101W.

[0067] The characteristic configurations of the control device 1 (1A, 1B) and the parking lock device 200A according to the above-described embodiments are summarized as follows.

[0068] [1] At least some embodiments of the control device (1) include: A control device (1) for a motor (100) including a stator (102) including a three-phase coil (101), a rotor (104) including a magnet (103) arranged opposite the stator (102), and a Hall element (H) for generating a detection signal indicative of an angular position (x) of the rotor (104), a position determination unit (40) for determining whether or not an angular position (x) of the rotor (104) obtained from a detection signal of the Hall element (H) has reached a target angular position (x*) of the rotor (104); a control mode switching unit (50) configured to switch a control mode between a feedback control mode in which energization control is performed for a pair of coils of a phase corresponding to the angular position (x) of the three-phase coils (101) based on an output determined by feedback control based on a deviation (Δx) between an angular position (x) of the rotor (104) obtained from a detection signal of a Hall element (H) and a target angular position (x*), and a stop control mode in which energization control is performed for a final energized coil that was last energized in the feedback control mode among the three-phase coils (101); Equipped with The control mode switching unit (50) is configured to switch the control mode from the feedback control mode to the stop control mode when the position determination unit (40) determines that the angular position (x) has reached the target angular position (x*).

[0069] According to the configuration [1], when the angular position (x) of the rotor (104) reaches the target angular position (x*), the control mode switching unit (50) operates to transition from the feedback control mode to the stop control mode, and in the stop control mode, energization control is performed on the coil that was last energized in the feedback control mode. Therefore, regardless of whether or not the next detection signal of the Hall element (H) indicating the new angular position (xH_3) of the rotor (104) is received, it is possible to apply to the rotor (104) a torque suitable for stopping the rotor (104) at the target angular position (x*) by energization control in the stop control mode, and thus it is possible to achieve high accuracy in the stopping position of the rotor (104).

[0070] [2] In some embodiments, in the configuration of [1] above, In the stop control mode, the control device (1) is configured to start energization control for the final energized coil after a first specified time (=t3-t2) has elapsed from the time when the angular position (x) of the rotor (104) obtained from the detection signal of the Hall element (H) reaches a target angular position (x*).

[0071] When energization control of the final energized coil is started in a state in which the angular position (x) of the rotor (104) is at the target angular position (x*), a torque that encourages the angular position (x) of the rotor (104) to pass through the target angular position (x*) is temporarily applied to the rotor. For example, when energization control in the "U→W" energization pattern in the stop control mode is started at time t2 in Fig. 7, a torque that encourages the rotor (104) to pass through the target angular position (x*) is applied to the rotor (104) by the composite magnetic flux of the "U→W" energization pattern (composite magnetic flux 105A in Fig. 10A). In this case, even if the rotor (104) can be finally stopped near the target angular position (x*) in the stop control mode, the temporary deviation from the target angular position (x*) increases slightly. In this regard, in the configuration [2] above, energization control for the final energized coil is started after a first specified time (=t3-t2) has elapsed from the time when the angular position (x) of the rotor (104) reaches the target angular position (x*). By appropriately setting the first specified time (=t3-t2), it is possible to avoid a situation in which a torque that promotes the angular position (x) of the rotor (104) passing through the target angular position (x*) temporarily acts on the rotor, and it is possible to selectively apply to the rotor (104) a torque that rotates the rotor (104) that has passed the target angular position (x*) in the reverse direction toward the target angular position (x*).

[0072] [3] In some embodiments, in the configuration of [1] or [2] above, In the stop control mode, the control device (1) is configured to continue the energization control for the final energized coil for a second specified time (t4-t3).

[0073] According to the configuration [3] above, by appropriately setting the second specified time (=t4-t3), it is possible to reliably return the angular position (x) of the rotor (104) to near the target angular position (x*) by controlling the energization of the final energized coil.

[0074] [4] In some embodiments, in any one of the configurations [1] to [3] above, The control device (1) In the feedback control mode, current supply control is performed for the coils of a pair of phases by PWM control based on a first duty ratio determined by feedback control, In the stop control mode, the current supply to the final energized coil is controlled by PWM control based on the second duty ratio, which is a fixed value. It is configured as follows.

[0075] According to the configuration [4] above, in the feedback control mode, by determining the first duty ratio according to the deviation (Δx) between the angular position (x) of the rotor (104) and the target angular position (x*), it is possible to quickly bring the angular position (x) of the rotor (104) close to the target angular position (x*) when the angular position (x) of the rotor (104) is significantly deviated from the target angular position (x*). In contrast, in the stop control mode, by adopting a fixed second duty ratio that is unrelated to the detection signal of the Hall element (H), it is possible to apply to the rotor (104) a torque suitable for returning the rotor (104) to the target angular position (x*), regardless of whether the next detection signal of the Hall element (H) is received.

[0076] [5] In some embodiments, in any one of the configurations [1] to [4] above, The control mode switching unit (50) is configured to switch the control mode to a high-precision stop control mode in which current is applied to the three-phase coil (101) in a current application pattern preset in accordance with the target angular position (x*) after executing the stop control mode.

[0077] According to the above configuration [5], by performing control in the high-precision stop control mode subsequent to the stop control mode, it is possible to bring the stop position of the rotor (104) even closer to the target angular position (x*).

[0078] [6] At least some embodiments of the parking lock device (200A) include: A parking lock gear (210); a motor (100) including a stator (102) including a three-phase coil (101), a rotor (104) including a magnet (103) arranged opposite the stator (102), and a Hall element (H) for generating a detection signal indicative of an angular position (x) of the rotor (104); A control device (1) having any one of the configurations [1] to [5] above for controlling a motor (100); a parking lock pole (220) configured to be driven by a motor (100) to be movable between a locked position in which the parking lock pole engages with the parking lock gear (210) and an unlocked position in which the parking lock pole is disengaged from the parking lock gear (210); Equipped with.

[0079] According to the configuration [6] above, the control device (1) having any one of the configurations [1] to [5] above is adopted, so that it is possible to achieve both the rapid arrival of the angular position (x) of the rotor (104) at the target angular position (x*) and high accuracy of the stopping position of the rotor (104), thereby improving both the responsiveness and accuracy of the parking lock device (200A).

[0080] In this specification, the expressions "comprise," "include," or "have" a certain element are not exclusive expressions excluding the presence of other elements. [Explanation of symbols]

[0081] 1 (1A, 1B): Control device 40:Position determination section 50: Control mode switching section 100: Motor 101(101U~101W): Coil 102: Stator 103: Magnet 104: Rotor 200A: Parking lock device 210: Parking lock gear 220: Parking lock pole D_fix: Second duty ratio H (H1 to H3): Hall element x: Angular position x*: Target angular position Δx: Deviation

Claims

1. A control device for a motor including a stator including a three-phase coil, a rotor including a magnet arranged to face the stator, and a Hall element for generating a detection signal indicating an angular position of the rotor, a position determination unit for determining whether the angular position of the rotor obtained from the detection signal of the Hall element has reached a target angular position of the rotor; a control mode switching unit configured to switch a control mode between a feedback control mode in which energization control is performed on a pair of coils of a phase corresponding to the angular position of the three-phase coils, based on an output determined by feedback control based on a deviation between the angular position of the rotor obtained from the detection signal of the Hall element and the target angular position, and a stop control mode in which energization control is performed on a final energized coil that was last energized in the feedback control mode, among the three-phase coils; Equipped with The control mode switching unit is configured to switch the control mode from the feedback control mode to the stop control mode when the position determination unit determines that the angular position has reached the target angular position. Motor control device.

2. In the stop control mode, the energization control for the final energized coil is started after a first specified time has elapsed from a point in time when the angular position of the rotor obtained from the detection signal of the Hall element reaches the target angular position. The motor control device according to claim 1 .

3. In the stop control mode, the energization control for the final energized coil is continued for a second specified time. The motor control device according to claim 1 or 2.

4. In the feedback control mode, the energization control is performed on the coils of the pair of phases by PWM control based on a first duty ratio determined by the feedback control; In the stop control mode, the energization control for the final energized coil is performed by PWM control based on a second duty ratio that is a fixed value.

3. The motor control device according to claim 1 or 2, configured as described above.

5. The control mode switching unit is configured to switch the control mode to a high-precision stop control mode in which current is applied to the three-phase coils in a current application pattern preset in accordance with the target angular position after the stop control mode is executed. The motor control device according to claim 1 or 2.

6. Parking lock gear, a motor including a stator including a three-phase coil, a rotor including a magnet arranged to face the stator, and a Hall element for generating a detection signal indicating an angular position of the rotor; A control device according to claim 1 or 2 for controlling the motor; a parking lock pole configured to be driven by the motor to be movable between a locked position in which the parking lock pole engages with the parking lock gear and an unlocked position in which the parking lock pole is disengaged from the parking lock gear; A parking lock device comprising:

Images