JP2024048927A - Motor Control Device - Google Patents

Abstract

[Problem] To provide a motor control device capable of appropriately driving a motor when one phase is broken. [Solution] An ECU 40 controls the driving of a motor having a three-phase motor winding 11, and includes a drive circuit 41 and a control unit 50. The drive circuit 41 has switching elements 411-413. The control unit 50 has a drive control unit 55 that controls the on/off operation of the switching elements 411-413 by feedback control based on the detection value of an encoder 13, and an abnormality determination unit 52 that determines a breakage fault in the motor winding 11. When a breakage fault has occurred in one phase and normal two-phase driving is performed in which the motor 10 is driven using the normal two phases, the drive control unit 55 performs a pre-start preparation process in which current is supplied to the energized held phase in a pattern different from the current supply pattern to the energized phase that is the energized phase when the normal two-phase driving is started, and then current is supplied to the energized held phase. When a retry condition is established in the pre-start preparation process, the pre-start preparation process is performed again. [Selected Figure] Figure 2

Description

The present invention relates to a motor control device.

Conventionally, motor control devices that control the drive of a motor are known. For example, in Patent Document 1, a disconnection detection circuit is provided in each current carrying line of the winding of each phase to detect disconnection.

JP 2004-129450 A

Even if a break occurs in one phase, if the inertia can pass the broken phase where the break occurs, the motor can continue to be driven. In Patent Document 1, the current-carrying phase that is switched to next after the broken phase is set as the first current-carrying phase, and the motor is driven using normal phases. However, when current starts to flow in one of the two normal phases, the stator salient poles of the current-carrying phase and the rotor recesses may face each other, and the current-carrying phase and the rotor teeth may not face each other.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a motor control device that can properly drive a motor when one phase is broken.

The motor control device of the present invention controls the drive of a motor (10) having a three-phase motor winding (11), and includes a drive control unit (41) and a control unit (50). The drive circuit has switching elements (411-413) that switch on and off the power supply to each phase of the motor winding. The control unit has a drive control unit (55) that controls the on/off operation of the switching elements by feedback control based on the detection value of a rotational position sensor (13) that detects the rotational position of the motor, and an abnormality determination unit (52) that determines a break fault in the motor winding.

When a wire breakage fault occurs in one of the three phases and normal two-phase drive is performed to drive the motor using the two normal phases, the drive control unit performs pre-start preparation processing to energize the energized held phase after energizing it in a pattern different from the energization pattern to the energized phase that is the energized phase when normal two-phase drive begins. If a retry condition is met in the pre-start preparation processing, the pre-start preparation processing is performed again. This makes it possible to drive the motor appropriately when one phase is broken.

1 is a perspective view showing a shift-by-wire system according to a first embodiment; 1 is a schematic configuration diagram showing a shift-by-wire system according to a first embodiment; FIG. 2 is a circuit diagram illustrating an ECU according to the first embodiment. FIG. 1 is a schematic diagram showing a motor according to a first embodiment. 4 is a map in which energized phase numbers are associated with energized phases according to the first embodiment. 5A and 5B are explanatory diagrams illustrating a disconnected phase and a facing position according to a switching direction according to the first embodiment. 5 is a schematic diagram showing an opposing state at the start of current flow when driving in the normal direction in the event of a U-phase disconnection in the first embodiment; FIG. FIG. 4 is an explanatory diagram for explaining motor driving in normal two phases in the first embodiment. FIG. 4 is an explanatory diagram illustrating switching of energized phases in the pre-switching preparation process according to the first embodiment. 5A to 5C are explanatory diagrams illustrating the behavior of the rotor in the pre-switching preparation process according to the first embodiment. 5 is a flowchart illustrating a range switching process according to the first embodiment. 5 is a time chart illustrating a range switching process according to the first embodiment. 10 is a flowchart illustrating a range switching process according to a second embodiment. 13 is a flowchart illustrating a range switching process according to a third embodiment. 13 is a time chart illustrating a range switching process according to a third embodiment. 13 is a flowchart illustrating a range switching process according to a fourth embodiment. 13 is a time chart illustrating a range switching process according to the fourth embodiment. 13 is a time chart illustrating a range switching process according to the fourth embodiment. 13 is a flowchart illustrating a range switching process according to a fifth embodiment. 13 is a time chart illustrating a range switching process according to the fifth embodiment. 13 is a time chart illustrating a range switching process according to the fifth embodiment. 13 is a time chart illustrating a range switching process according to the fifth embodiment. 23 is a flowchart illustrating a startup process according to the sixth embodiment. 13 is a flowchart illustrating a range switching process according to a sixth embodiment. 13 is a time chart illustrating a range switching process according to the sixth embodiment. 13 is a time chart illustrating a range switching process according to the sixth embodiment. 13 is a time chart illustrating a range switching process according to the sixth embodiment.

First Embodiment
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A motor control device according to the present invention will now be described with reference to the drawings. In the following, in a number of embodiments, substantially the same components are designated by the same reference numerals, and description thereof will be omitted.

The first embodiment is shown in Figures 1 to 12. As shown in Figures 1 and 2, the shift-by-wire system 1 includes a motor 10, a detent mechanism 20, a parking lock mechanism 30, and an ECU 40 as a motor control device.

The motor 10 rotates by receiving power from a battery 90 mounted on the vehicle (not shown) and functions as a drive source for the detent mechanism 20. The motor 10 is, for example, a switched reluctance motor.

As shown in Figures 3 and 4, the motor 10 has a stator 101, a rotor 103, and a motor winding 11. The motor winding 11 has a U-phase coil 111, a V-phase coil 112, and a W-phase coil 113, and is wound around the salient pole 102 of the stator 101. The coils 111 to 113 are connected at a connection portion 115. The connection portion 115 is connected to the battery 90 via a motor relay 91 and a fuse 92.

The rotor 103 has salient poles and is rotatably mounted radially inside the stator 101. The rotor 103 is rotationally driven by switching the energized phase of the coils 111 to 113. In this embodiment, the stator 101 has 12 salient poles and the rotor 103 has 8 salient poles. Hereinafter, the salient poles of the rotor 103 will be referred to as convex portions 104, and the spaces between the convex portions will be referred to as concave portions 105.

The encoder 13 is a magnetic rotary encoder that detects the rotational position of the rotor 103. The encoder 13 is composed of Hall elements 131 and 132 for magnetic detection, a magnet 135 that rotates integrally with the rotor 103, and the like. The Hall elements 131 and 132 output a pulse signal every predetermined angle in synchronization with the rotation of the rotor 103. In this embodiment, the Hall elements 131 and 132 output a Lo signal when facing the N pole, and a Hi signal when facing the S pole.

The magnet 135 is formed in an annular shape and is arranged coaxially with the rotor 103. The magnet 135 is magnetized with alternating north and south poles at equal pitches in the circumferential direction. In this embodiment, the magnetization pitch is 7.5°. This magnetization pitch is the same as the rotation angle of the rotor 103 per excitation of the motor 10. In other words, when the 1-2 phase excitation method in which the energized phase is switched from U phase to UV phase to V phase to VW phase to W phase to WU phase is completed by switching the energized phase six times, the rotor 103 rotates through a mechanical angle of 7.5 x 6 = 45°.

Hall elements 131 and 132 are arranged on the same circumference with a phase difference of 90° electrical angle. In this embodiment, an electrical angle of 90° corresponds to a mechanical angle of 3.75°, and hall elements 131 and 132 are arranged with an interval of 48.75°. In this embodiment, the signal of hall element 131 is phase A, and the signal of hall element 132 is phase B. Although encoder 13 is a two-phase encoder, it may be a three-phase encoder, or may output a Z-phase signal as a reference signal in addition to the detection signal.

Returning to FIG. 1, the reducer 14 is provided between the motor shaft of the motor 10 and the output shaft 15, and reduces the rotation of the motor 10 before outputting it to the output shaft 15. This transmits the rotation of the motor 10 to the detent mechanism 20. The output shaft sensor 16 is, for example, a potentiometer, and detects the rotational position of the output shaft 15 (see FIG. 2).

The detent mechanism 20 has a detent plate 21, a detent spring 25, and a detent roller 26, and transmits the rotational driving force output from the reduction gear 14 to the parking lock mechanism 30.

The detent plate 21 is fixed to the output shaft 15 and driven by the motor 10. On the detent spring 25 side of the detent plate 21, two valleys 211, 212 and a peak 215 separating the valleys 211, 212 are provided.

The detent spring 25 is a plate-shaped member that can be elastically deformed, and has a detent roller 26 at its tip. The detent spring 25 biases the detent roller 26 toward the center of rotation of the detent plate 21.

When a rotational force of a predetermined magnitude or more is applied to the detent plate 21, the detent spring 25 elastically deforms, and the detent roller 26 moves between the valleys 211 and 212. When the detent roller 26 fits into either of the valleys 211 or 212, the oscillation of the detent plate 21 is restricted, and the state of the parking lock mechanism 30 and the shift range of the automatic transmission 5 are determined.

The parking lock mechanism 30 has a parking rod 31, a cone 32, a parking lever 33, a shaft 34, and a parking gear 35. The parking rod 31 is formed in a generally L-shape, and one end 311 is fixed to the detent plate 21. A cone 32 is provided on the other end 312 of the parking rod 31. The cone 32 is formed so that its diameter decreases toward the other end 312. When the detent plate 21 rotates in a direction in which the detent roller 26 fits into the valley 211 corresponding to the P range, the cone 32 moves in the direction of the arrow P.

The parking lever 33 abuts against the conical surface of the cone 32 and is arranged to be able to swing around the shaft 34. A protrusion 331 that can mesh with the parking gear 35 is provided on the parking lever 33's parking gear 35 side. When the cone 32 moves in the direction of arrow P due to the rotation of the detent plate 21, the parking lever 33 is pushed up and the protrusion 331 meshes with the parking gear 35. On the other hand, when the cone 32 moves in the direction of arrow not P, the meshing between the protrusion 331 and the parking gear 35 is released.

The parking gear 35 is connected to a drive shaft (not shown) and is arranged to be able to mesh with a protrusion 331 of the parking lever 33. When the parking gear 35 meshes with the protrusion 331, the rotation of the drive shaft is restricted. When the shift range is a not P range other than the P range, the parking gear 35 is not locked by the parking lever 33, and the rotation of the drive shaft is not hindered by the parking lock mechanism 30. Also, when the shift range is the P range, the parking gear 35 is locked by the parking lever 33, and the rotation of the drive shaft is restricted.

In this embodiment, the rotation direction of the motor 10 when switching from the P range to the notP range is the forward direction, and the rotation direction of the motor 10 when switching from the notP range to the P range is the reverse direction.

As shown in FIG. 2 and FIG. 3, the ECU 40 includes a drive circuit 41, a current detection unit 45, a voltage detection circuit 46, and a control unit 50. The drive circuit 41 has three switching elements 411, 412, and 413. The switching elements 411 to 413 are provided corresponding to the coils 111 to 113, respectively, and switch the current supply to the corresponding phase. In this embodiment, the switching elements 411 to 413 are provided between the coils 111 to 113 and ground. The switching elements 411 to 413 in this embodiment are MOSFETs, but may be IGBTs or the like.

The current detection unit 45 is provided in the collective wiring that connects the sources of the switching elements 411 to 413 to ground, and detects the sum of the currents flowing through the coils 111 to 113. Hereinafter, the current detected by the current detection unit 45 is referred to as the motor current Im. The current detection unit 45 may be provided at any location where it is possible to detect the currents in the coils 111 to 113, and may also be provided for each phase.

The voltage detection circuit 46 is connected between the coils 111-113 and the switching elements 411-413 to detect the terminal voltage of each phase. The relay driver 48 controls the on/off operation of the motor relay 91.

The control unit 50 is mainly composed of a microcomputer and includes a CPU, ROM, RAM, I/O, and bus lines connecting these components (none of which are shown in the figure). Each process in the control unit 50 may be software processing in which the CPU executes a program prestored in a physical memory device such as a ROM (i.e., a readable non-transitory tangible recording medium), or it may be hardware processing using a dedicated electronic circuit.

The control unit 50 controls the switching of the shift range by controlling the drive of the motor 10 based on a shift signal corresponding to the driver's requested shift range, a signal from the brake switch, the accelerator opening, the vehicle speed, etc.

The control unit 50 has, as functional blocks, a signal acquisition unit 51, an abnormality determination unit 52, and a drive control unit 55. The signal acquisition unit 51 acquires detection signals from the encoder 13, the output shaft sensor 16, the current detection unit 45, the voltage detection circuit 46, and the like. The abnormality determination unit 52 determines an abnormality in the shift-by-wire system 1, such as a disconnection abnormality.

The drive control unit 55 controls the driving of the motor 10 by controlling the on/off operation of the switching elements 411 to 413. In this embodiment, the motor 10 is driven by switching the current-carrying phase of the motor winding 11 through feedback control based on the encoder count value.

As shown in FIG. 5, the control unit 50 stores a map in which the energized phase number corresponds to the energized phase, and rotates the motor 10 by shifting the energized phase number by 1 and switching the energized phase each time a pulse edge of the encoder signal is detected. When rotating the motor 10 in the forward direction, the energized phase number is increased by 1 each time a pulse edge of the encoder signal is detected, and when rotating the motor 10 in the reverse direction, the energized phase number is decreased by 1. The energized phase number can also be regarded as the remainder when the encoder count value is divided by 12, for example.

In this embodiment, if a break occurs in one phase, the motor 10 is driven by energizing the two normal phases through feedback control, thereby switching the range. For example, when the U phase is broken, no torque is generated in energized phases 2 and 3, where only the U phase is energized under normal conditions, but the motor 10 can continue to be driven by passing through this region with inertia.

Here, when switching ranges due to one-phase disconnection, it is desirable to start the switching drive from a so-called "one-phase, one-tooth" state in which the energized phase faces the convex portion 104 of the rotor 103. Hereinafter, the state in which the U-phase salient pole 102 and the convex portion 104 of the rotor 103 face each other with one tooth per phase will be referred to as "U-phase facing", the state in which the V-phase salient pole 102 and the convex portion 104 face each other with one tooth per phase will be referred to as "V-phase facing", and the state in which the W-phase salient pole 102 and the convex portion 104 face each other with one tooth per phase will be referred to as "W-phase facing".

As shown in FIG. 6, the opposing positional relationship between the salient poles 102 of the stator 101 and the convex portions 104 of the rotor 103 at the start of switching is set according to the broken phase and the rotation direction of the motor 10. When the U-phase is broken and the switching direction is forward, the range switching starts from the V-phase facing state, and when it is reverse, the range switching starts from the W-phase facing state. When the V-phase is broken and the switching direction is forward, the W-phase facing state, and when it is reverse, the range switching starts from the U-phase facing state. When the W-phase is broken and the switching direction is forward, the U-phase facing state, and when it is reverse, the range switching starts from the V-phase facing state. Below, an example in which the switching direction is forward when the U-phase is broken is mainly described.

As shown in FIG. 7, when switching to the forward direction due to a U-phase break, range switching begins from a state in which the V-phase is energized and V-phase is opposed. In FIG. 8, the upper row shows the switching of energized phases, and the lower row shows the motor torque corresponding to the energized phases in the upper row. As shown in FIG. 8, by switching from a state in which the V-phase is energized and V-phase is opposed to VW-phase energized, and energizing to the normal phase, W-phase energized, torque is generated to rotate the rotor 103.

If no U-phase breakage occurs, the W-phase is energized, followed by the WU-phase, U-phase, and UV-phase. On the other hand, when the U-phase is broken, current cannot be passed to the U-phase coil 111, so in the area where the WU-phase should be energized, the W-phase continues to be energized, reducing the motor torque, and in the area where the U-phase should be energized, the motor torque is zero. If this area is passed by inertia, current is passed to the V-phase in the UV-phase energization area, increasing the motor torque, and the motor 10 continues to rotate. In Figures 7 and 8, the energized phase coils are shown with solid lines, the non-energized phase coils are shown with dashed lines, and the broken state is shown by omitting the illustration of the U-phase coil 111.

Here, if only V-phase current is applied before range switching, the recess 105 of the rotor 103 and the V-phase salient pole 102 may face each other when the V-phase is applied, and in this state, driving cannot be started from the V-phase facing state. If the current phase is switched from V-phase current to VW-phase current from a state in which the V-phase salient pole 102 and the recess 105 of the rotor 103 face each other, the rotor 103 may rotate in the reverse direction, or the rotation speed may be insufficient in the area that you want to pass through due to inertia, and it may not be possible to pass through the open phase.

In this embodiment, therefore, a pre-switching preparation process is performed to align the positions of the stator 101 and rotor 103 so that they are reliably in the opposing state shown in FIG. 6. In the pre-switching preparation process, as shown in FIG. 9, one-phase current, two-phase current, and one-phase current are performed in sequence to ensure that the current-carrying phase at the start of switching is opposed in a one-phase, one-tooth state.

Specifically, when the U-phase is broken and the switching direction is forward, W-phase energization, VW-phase energization, and V-phase energization are performed as pre-switching preparations, and when the switching direction is reverse, V-phase energization, VW-phase energization, and W-phase energization are performed as pre-switching preparations. When the V-phase is broken and the switching direction is forward, U-phase energization, WU-phase energization, and W-phase energization are performed as pre-switching preparations, and when the switching direction is reverse, W-phase energization, WU-phase energization, and U-phase energization are performed as pre-switching preparations. When the W-phase is broken and the switching direction is forward, V-phase energization, UV-phase energization, and U-phase energization are performed as pre-switching preparations, and when the switching direction is reverse, U-phase energization, UV-phase energization, and V-phase energization are performed as pre-switching preparations. Below, the first 1-phase energization in the pre-switching preparations is referred to as energization status ST1, the next 2-phase energization is referred to as energization status ST2, and the state in which the 1-phase 1-tooth state is maintained by 1-phase energization to the energized phase at the start of switching is referred to as energization status ST3.

Figure 10 shows the pre-switching preparations for achieving the V-phase opposing state when the U-phase is broken. First, W-phase current is applied, so that the convex portion 104 faces the W-phase. When this state is switched to VW-phase current, the rotor 103 rotates, and the convex portion 104 faces the V-phase and W-phase, resulting in a so-called "two-phase, two-tooth" state. By switching from the two-phase, two-tooth state to V-phase current, it is possible to reliably achieve a one-phase, one-tooth state with the V-phase opposing. Note that even if the so-called "one-phase, two-tooth" state occurs when the W-phase is current-applied, in which the concave portion 105 faces the W-phase, it is possible to achieve a one-phase, one-tooth state with the V-phase opposing when the V-phase is current-applied, by applying V-phase current after VW-phase current-applied.

The range switching process of this embodiment will be described based on the flowchart in FIG. 11. This process is executed by the control unit 50 at a predetermined cycle. In S101, the control unit 50 judges whether or not a one-phase break has been detected. If it is judged that a one-phase break has not been detected (S101: NO), the process from S102 onwards is skipped. Note that the detection of a one-phase break is performed in a process separate from this embodiment, and is judged, for example, based on the detection value of the voltage detection circuit 46, but the details of the detection method are not important. Also, when all phases are normal, range switching is performed in a process separate from this process. If it is judged that a one-phase break has been detected (S101: YES), proceed to S102.

In S102, the control unit 50 determines whether or not there is a request to switch the shift range. If it is determined that there is no request to switch (S102: NO), the process from S103 onwards is skipped and the standby mode continues. If it is determined that there is a request to switch (S102: YES), the process proceeds to S103.

In S103, the drive control unit 55 applies current in the current status ST1. For example, when the U phase is disconnected and the switching direction is forward, current is applied to the W phase. In S104, the drive control unit 55 determines whether the current application hold time Xh1 in the current application status ST1 has elapsed. If it is determined that the current application hold time Xh1 has not elapsed (S104: NO), the process returns to S103 and current application in the current application status ST1 continues. If it is determined that the current application hold time Xh1 has elapsed (S104: YES), the process proceeds to S105.

In S104, the drive control unit 55 applies current in the current status ST2. For example, when the U phase is disconnected, two-phase current is applied to the normal VW phase regardless of the switching direction. In S106, the drive control unit 55 determines whether the current hold time Xh2 in the current status ST2 has elapsed. If it is determined that the current hold time Xh2 has not elapsed (S106: NO), the process returns to S105 and current is continued in the current status ST2. If it is determined that the current hold time Xh2 has elapsed (S106: YES), the process proceeds to S107.

In S107, the drive control unit 55 applies current in the current status ST3. For example, when the U-phase is disconnected and the switching direction is forward, current is applied to the V-phase. In S108, the drive control unit 55 determines whether the current hold time Xh3 in the current status ST3 has elapsed. If it is determined that the current hold time Xh3 has not elapsed (S108: NO), the process returns to S107 and current is continued in the current status ST3. If it is determined that the current hold time Xh3 has elapsed (S108: YES), the process proceeds to S109 and the pre-switching preparation completion flag is turned on. The pre-switching preparation completion flag is turned off at any time after the start of range switching.

In S110, the drive control unit 55 drives the motor 10 from a one-phase, one-tooth opposing state at a predetermined position according to the broken phase and rotation direction, and performs range switching by feedback control in normal two phases. In S111, the control unit 50 determines whether the range switching is complete. If it is determined that the range switching is not complete (S111: NO), the process returns to S109 and continues feedback control in normal two phases. If it is determined that the range switching is complete (S111: YES), the process transitions to standby mode and ends this process.

The range switching process of this embodiment will be described based on the time chart in Figure 12. In Figure 12, the horizontal axis represents a common time axis, and from the top, the motor control mode, one-phase breakage detection status, pre-switching preparation completion flag, motor rotation angle, and current phase are shown. The motor rotation angle is a value that can be converted from the encoder count value, and the actual value is shown as a solid line, the target value as a dashed line, and when the detent roller 26 is at the bottom of the valley portion 211, it is shown as P, and when it is at the bottom of the valley portion 212, it is shown as notP. The same applies to Figure 15, etc., described later.

In Figure 12, the vibration components of the rotor 103 due to switching of the current status are omitted. The current phase numbers for the current phases at the time of shift switching are written in parentheses. For simplicity, the current phase numbers are the numbers at the time of switching. Also, for the sake of explanation, the switching of current phases during shift switching is shown on an expanded time scale and does not correspond to the progression of the motor rotation angle.

When one phase break occurs at time x0, the abnormality is confirmed at time x1, and then a shift range switching request is input at time x2, pre-switching preparation processing is performed. In the pre-switching preparation processing, the energized phase is switched at predetermined time intervals in the order of energized status ST1, ST2, ST3. The energized phases of energized status ST1, ST2, ST3 are set according to the broken phase and switching direction.

Note that since the energization status ST2 is two-phase energization, the rotor 103 is likely to stabilize, and the energization hold time Xh2 can be a relatively short time. In addition, since it is desirable for the energization status ST3 to be reliably held in a one-phase, one-tooth state, it is set to a relatively long time. Therefore, in this embodiment, Xh2≦Xh1≦Xh3 is set.

When the pre-switch preparation process is completed at time x3, the pre-switch preparation completion flag is turned on, and range switching is performed with feedback control using the two normal phases. When the target attainment determination range is reached at time x4, stop control is performed. The stop control in this embodiment is fixed phase current supply to the two normal phases. When a predetermined time has elapsed from the start of stop control at time x5, all switching elements are turned off, and the system transitions to standby mode.

In this embodiment, when the motor 10 is driven by energizing the normal two phases when one phase is broken, one phase energization, two phase energization, and one phase energization are performed in that order as pre-switching preparation processing before starting to drive. This allows the motor 10 to start driving from a one-phase, one-tooth state in which the convex portion 104 of the rotor 103 faces the energized phase at the start of switching.

As described above, the ECU 40 controls the driving of a motor having three-phase motor windings 11, and includes a drive circuit 41 and a control unit 50. The drive circuit 41 has switching elements 411-413 that switch on and off the power supply to each phase of the motor windings 11. The control unit 50 has a drive control unit 55 that controls the on/off operation of the switching elements 411-413 by feedback control based on the detection value of the encoder 13 that detects the rotational position of the motor 10, and an abnormality determination unit 52 that determines whether the motor windings 11 have an open circuit.

When a wire breakage fault occurs in one of the three phases and normal two-phase drive is performed to drive the motor 10 using the two normal phases, the drive control unit 55 performs pre-switching preparation processing to energize the energized phase after energizing it in a pattern different from the energization pattern to the energized phase that is the energized phase at the start of normal two-phase drive. Here, a wire breakage fault is a fault that prevents current from flowing through the coil, and includes a wire breakage in the harness and a switching element stuck off.

By performing pre-switching preparation processing, the rotor 103 can be rotated to a position where the stator 101 and rotor 103 face each other and torque can be generated in normal two-phase drive. This allows the motor 10 to be driven appropriately when one phase is broken.

As a pre-energization preparation process, the drive control unit 55 switches the energization phase in the order of energization status ST1, which is a first energization process in which energization is performed to phase 1 of the normal phases, energization status ST2, which is a second energization process in which energization is performed to phase 2 of the normal phases, and energization status ST3, which is a third energization process in which energization is performed to the energization-maintained phase of phase 1. This allows the opposing positions of the stator 101 and the rotor 103 to be appropriately aligned to a predetermined position.

The energized phase in the pre-switching preparation process is set according to the disconnection phase and the rotation direction of the motor 10, and the energized phase of the energization status ST1 is the phase that is energized before the disconnection phase in terms of the switching order of the energized phases. This allows the opposing positions of the stator 101 and the rotor 103 to be properly aligned.

Second Embodiment
The second embodiment is shown in Fig. 13. In the following embodiment, the pre-switching preparation process is mainly different from the above embodiment, and this point will be mainly described. The range switching process of this embodiment will be described based on the flowchart of Fig. 13. Fig. 13 differs from Fig. 11 in that S120 is added between S106 and S107.

In S120, which is transitioned to after the energization status ST2, the control unit 50 sets the energization hold time Xh3 of the energization status ST3 according to the ambient temperature H. In detail, when the ambient temperature H is less than the first judgment threshold Hth1, the energization hold time is Xp. When the ambient temperature H is equal to or greater than the first judgment threshold Hth1 and less than the second judgment threshold Hth2, the energization hold time is Xq. When the ambient temperature H is equal to or greater than the second judgment threshold Hth2, the energization hold time is Xr. The magnitude relationship of each value is Hth1<Hth2, Xp<Xq<Xr. The ambient temperature H is the environmental temperature of the motor 10, and may be the temperature of the motor 10 itself, or may be the temperature of other parts arranged near the motor 10, such as the oil temperature of the transmission.

The energization status ST13 is maintained in a one-phase, one-tooth state with one-phase energization. Here, in the case of one-phase energization, the rotor 103 is likely to vibrate. Also, when the ambient temperature H is low, friction is large and the rotor 103 is less likely to vibrate. Therefore, in this embodiment, the lower the ambient temperature H, the shorter the energization hold time Xh3 in the energization status ST3 can be, thereby improving responsiveness. In this example, the energization hold time Xh3 is set to three stages using two judgment thresholds Hth1 and Hth2, but the judgment threshold may be 1 or more, and the number of stages does not matter. Also, instead of threshold judgment, the energization hold time Xh3 may be set by calculation using a map or function according to the ambient temperature H. Furthermore, similar to the energization status ST3, the energization hold time Xh1 of the energization status ST1, which is one-phase energization, may also be variable according to the ambient temperature H.

In this embodiment, the energization time in the pre-switching preparation process is variable depending on the motor temperature. In particular, the lower the motor temperature, the shorter the energization time of energization status ST3 is set. This allows the energization time to be set appropriately depending on the motor temperature, which contributes to improving responsiveness especially at low temperatures. It also provides the same effects as the above embodiment.

Third Embodiment
The third embodiment is shown in Figures 14 and 15. The range switching process of this embodiment will be described with reference to the flowchart of Figure 14. The processes of S201 to S204 are similar to the processes of S101 to S104 in Figure 11.

In S205, which is reached after the current holding time Xh1 in current status ST1 has elapsed, the control unit 50 determines whether the amplitude A1 is equal to or less than the amplitude determination threshold Ath1. The amplitude A1 is, for example, the difference between the maximum and minimum values of the n encoder count values prior to the current holding time Xh1 having elapsed. The details of the calculation of the amplitude A1 are not important. The amplitude determination threshold Ath1 is set to a value at which the rotor 103 can be considered to be held in a one-phase, one-tooth state. The same applies to the amplitude A3 and the amplitude determination threshold Ath3 described below. The amplitude determination thresholds Ath1 and Ath3 may be the same or different.

If it is determined that the amplitude A1 is equal to or less than the amplitude determination threshold Ath1 (S205: YES), the process proceeds to S207, and energization begins in energization status ST2. If it is determined that the amplitude A1 is greater than the amplitude determination threshold Ath1 (S205: NO), the process proceeds to S206, and energization in energization status ST1 is extended by a predetermined time Xa. Then, the process proceeds to S207, and energization begins in energization status ST2. The processes of S207 to S210 are the same as those of S105 to S108.

In S211, which is reached after the current holding time Xh3 in current status ST3 has elapsed, the control unit 50 determines whether the amplitude A3 is equal to or less than the amplitude determination threshold Ath3. If it is determined that the amplitude A3 is equal to or less than the amplitude determination threshold Ath3 (S211: YES), the control unit 50 proceeds to S213 and performs range switching in normal two phases. If it is determined that the amplitude A3 is greater than the amplitude determination threshold Ath3 (S211: NO), the control unit 50 proceeds to S211 and extends current flow in current status ST3 by a predetermined time Xc. The extension times for current status ST1 and ST3 may be the same or different. The processes in S213 to S215 are the same as those in S109 to S111 in FIG. 11.

The range switching process of this embodiment will be described based on the time chart in FIG. 15. Here, the amplitude determination thresholds Ath1 and Ath3 are described as being equal. For the sake of explanation, the vibration component in one-phase current flow is emphasized. The process from time x10 to x12 is the same as the process from time x0 to x2 in FIG. 12.

At time x12, the rotor 103 vibrates due to one-phase current flow in the current flow status ST1, but because the amplitude A1 at time x13 after the current flow holding time Xh1 has elapsed is equal to or less than the amplitude determination threshold Ath1, the current flow status ST1 is not extended and is switched to current flow status ST2. In current flow status ST2, the vibration of the rotor 103 is relatively small due to two-phase current flow.

At time x14, when the energization hold time Xh2 has elapsed since the start of energization status ST2, the energization status ST2 is switched to energization status ST3 and one-phase energization is performed, causing the rotor 103 to vibrate. Since the amplitude A3 at time x15, when the energization hold time Xh3 has elapsed, is greater than the amplitude determination threshold Ath3, energization in energization status ST3 is extended for a predetermined time Xc. In this example, the amplitude converges to less than or equal to the amplitude determination threshold Ath3 while the energization status ST3 is being extended. After the energization status ST3 is extended for the predetermined time Xc, range switching is performed with normal two phases. The processing from time x16 onwards is the same as the processing from time x3 onwards in FIG. 12.

In this embodiment, if the amplitudes A1, A3 of the motor rotation angle when the energization holding time has elapsed are greater than the amplitude determination thresholds Ath1, Ath3 in at least one of the energization status ST1 and the energization status ST3, the energization time is extended. This makes it possible to improve the accuracy of maintaining the opposing positions in one-phase energization, where the opposing state between the stator 101 and the rotor 103 is more likely to be unstable compared to two-phase energization. It also provides the same effects as the above embodiment.

Fourth Embodiment
A fourth embodiment is shown in Fig. 16 to Fig. 18. Fig. 16 differs from Fig. 14 in that S231 and S232 are used instead of S206, and S233 and S234 are used instead of S212. In S205, which is performed after the energization hold time Xh1 has elapsed in the energization status ST1, if it is determined that the amplitude A1 is greater than the amplitude determination threshold Ath1 (S205: NO), the energization status ST1 is extended in S231.

In S232, the control unit 50 determines whether the timeout time Xout1 has elapsed since the start of the extension of the energized status ST1. If it is determined that the timeout time has not elapsed (S232: NO), the extension of the energized status ST1 continues and the process returns to S205. If it is determined that the timeout time Xout1 has elapsed (S232: YES), the process proceeds to S207 and the energized state is switched to the energized status ST2.

In the energization status ST3, in S211, which is reached after the energization hold time Xh3 has elapsed, if it is determined that the amplitude A3 is greater than the amplitude determination threshold Ath3 (S211: NO), the energization status ST3 is extended in S233.

In S234, the control unit 50 determines whether the timeout time Xout3 has elapsed since the start of the extension of the power-on status ST3. If it is determined that the timeout time Xout3 has not elapsed (S234: NO), the extension of the power-on status ST3 continues and the process returns to S205. If it is determined that the timeout time Xout3 has elapsed (S234: YES), the process proceeds to S213.

The range switching process of this embodiment will be described based on the time charts of Figures 17 and 18. Figure 17 shows a case where the vibration subsides before the timeout period Xout3. The process from time x20 to time x25 is the same as the process from time x10 to time x15 in Figure 15. At time x25, the amplitude A3 is greater than the amplitude determination threshold Ath3, so the energization in the energization status ST3 is extended.

At time x26, before the timeout period Xout3 has elapsed since time x25, which is the extension start time of the energization status ST3, the amplitude A3 is smaller than the amplitude determination threshold Ath3, so the pre-switching preparation completion flag is turned on and range switching is performed in normal two phases. The processing from time x26 onwards is the same as in the above example.

Figure 18 shows a case where the vibration does not converge within the timeout period Xout3. The processing from time x30 to time x35 is the same as the processing from time x10 to time x15 in Figure 15. At time x35, the amplitude A3 is greater than the amplitude determination threshold Ath3, so the current flow in the current flow status ST3 is extended.

At time x36, when the timeout time Xout3 has elapsed since time x35, which is the start time of the energization status ST3, the amplitude A3 continues to be greater than the amplitude determination threshold Ath3, but the pre-switching preparation flag is turned on as a timeout, and range switching is performed in normal two phases. The processing from time x36 onwards is the same as in the example above.

The current status ST3 immediately before the completion of pre-switching preparation is one-phase current, so the rotor 103 is prone to vibration and the opposing position is difficult to determine. Therefore, if the timeout period Xout3 has elapsed, even if the vibration has not subsided, it is assumed that the rotor 103 has completed moving to the specified opposing position, and pre-switching preparation is completed. This allows the range switching to begin appropriately.

In this embodiment, the drive control unit 55 transitions to the next current flow process when the timeout times Xout1 and Xout3 have elapsed since the start of the current flow extension. In detail, when the timeout time Xout1 has elapsed in current flow status ST1, the drive control unit 55 transitions to current flow status ST2, and when the timeout time Xout3 has elapsed in current flow status ST3, the drive control unit 55 starts range switching in normal two-phase drive. This allows the drive control unit 55 to appropriately switch to the next current flow process even if the vibrations in one-phase current flow do not subside. It also provides the same effects as the above embodiment.

Fifth Embodiment
A fifth embodiment is shown in Fig. 19 to Fig. 22. In this embodiment, if the preparation for starting switching is not properly performed during the preparation before starting switching, a retry is performed. The range switching process of this embodiment will be described with reference to the flowchart of Fig. 19.

The processes of S301 and S302 are the same as those of S101 and S102 in FIG. 11. If it is determined that a switch request has been made (S302: YES), the process proceeds to S303, where a retry flag, which will be described later, is turned off.

The processing of S304 to S306 is the same as the processing of S203 to S205 in FIG. 14. If it is determined that the amplitude A1 is equal to or less than the amplitude determination threshold Ath1 (S306: YES), the process proceeds to S308. If it is determined that the amplitude A1 is greater than the amplitude determination threshold Ath1 (S306: NO), the process proceeds to S307, and the retry flag is turned on.

The processing of S308 to S312 is the same as the processing of S207 to S211 in FIG. 14. If it is determined that the amplitude A3 is greater than the amplitude determination threshold Ath3 (S312: NO), the process proceeds to S314, where the retry flag is turned on. If it is already on, the state is maintained. If it is determined that the amplitude A3 is equal to or less than the amplitude determination threshold Ath3 (S312: YES), the process proceeds to S313.

In S313, the control unit 50 determines whether a voltage drop has occurred between the start of current flow in the current flow status ST1 and the end of current flow in the current flow status ST3, causing the motor voltage Vm to fall below the voltage determination threshold Vth. Instead of a voltage drop, the control unit 50 may determine whether a current drop has occurred, causing the motor current Im to fall below the current determination threshold Ith. If it is determined that no voltage drop has occurred (S313: NO), the control unit 50 proceeds to S315. If it is determined that a voltage drop has occurred (S313: YES), the control unit 50 proceeds to S314, where the retry flag is turned on. Note that, for the sake of explanation, the control unit 50 determines whether a voltage drop has occurred after the current flow status ST3 ends, but the control unit 50 may also perform voltage monitoring separately from this process and turn on the retry flag when a voltage drop occurs.

In S315, the control unit 50 determines whether the retry flag is on. If it is determined that the retry flag is off (S315: NO), the control unit 50 proceeds to S319. If it is determined that the retry flag is on (S315: YES), the control unit 50 proceeds to S316 and increments the retry counter Cr.

In S317, the control unit 50 determines whether the retry counter Cr is smaller than the count determination threshold Cth. If it is determined that the retry counter Cr is smaller than the count determination threshold Cth (S317: YES), the process returns to S303, the retry flag is turned off, and pre-switch preparation is retried. If it is determined that the retry counter Cr is equal to or greater than the count determination threshold Cth (S317: NO), the process proceeds to S318.

In S318, the control unit 50 determines whether the input switching request is a switch from P range to not P range. If it is determined that the request is a switch from P range to not P range (S303: YES), the processing from S319 onwards is skipped. If it is determined that the request is a switch from not P range to P range (S318: NO), the process proceeds to S319, where the retry flag is turned off and the pre-switch preparation completion flag is turned on. The processing of S320 and S321 is the same as the processing of S110 and S111 in FIG. 11.

In other words, in this embodiment, if the retry flag is set even after a predetermined number of retries of the pre-switching preparation process, range switching is performed with normal two-phase drive on the P-in side, and range switching is not performed on the P-out side. Here, the state in which the retry flag is set can be considered as a state in which the retry condition is met. Note that S318 may be omitted, and normal two-phase drive may be performed after a predetermined number of retries regardless of the range switching direction.

The range switching process of this embodiment will be described based on the time charts of Figures 20 to 22. Figure 20 shows an example of a case where a voltage drop occurs during pre-switching preparation processing, with a common time axis as the horizontal axis, and from the top, motor control, one-phase breakage detection state, pre-switching preparation completion flag, retry flag, retry counter, motor voltage, and current-carrying phase. The same is true for Figure 22.

The processing from time x40 to time x42 is the same as the processing from time x0 to time x2 in FIG. 12. When the motor voltage Vm falls below the voltage determination threshold Vth at time x43, the retry flag is turned on.

At time 44 when the power-on status ST3 ends, the retry flag is on, so the pre-switch preparation process is retried. At time x44, the retry flag is turned off and the retry counter is incremented. From time x44 to time x45, power is again applied with the power-on statuses ST1 to ST3.

When the current status ST3 in the retry ends at time x45, no voltage drop during this retry is detected and the retry flag is off, so the pre-switching preparation complete flag is turned on and normal two-phase range switching is performed. The processing after time x45 is substantially the same as the processing after time x3 in FIG. 12. The retry counter is reset at any timing after the start of range switching. In FIG. 20, the retry counter is reset when the pre-switching preparation complete flag is turned off, but it may be reset at a different timing.

Figure 21 shows an example of a case where the vibration in the energization status ST3 has not converged, with the horizontal axis representing a common time axis, and from the top, motor control, one-phase breakage detection state, pre-switching preparation completion flag, retry flag, retry counter, rotation angle sensor, and energization phase. The processing from time x50 to time x52 is the same as the processing from time x0 to time x2 in Figure 12.

When the energization status ST3 ends at time x53, the amplitude A3 is greater than the amplitude judgment threshold Ath3, so the retry flag is turned on and the pre-switching preparation process is retried at time x54. At time x54, the retry flag is turned off and the retry counter is incremented. Note that for the sake of explanation, time x53 is shifted to the left side of the page in FIG. 21. In this example, the amplitude A1 after the energization status ST1 ends is less than or equal to the amplitude judgment threshold Ath1, but if the amplitude A1 is greater than the amplitude judgment threshold Ath1, the retry flag is set when the energization status ST1 ends.

At time x55, when the current-carrying status ST3 in the retry ends, the amplitudes A1 and A3 are equal to or less than the amplitude judgment thresholds Ath1 and Ath3, and the retry flag is not turned on, so range switching is performed in normal two phases. The processing after time x55 is the same as the processing after time x3 in FIG. 12.

Figure 22 shows an example of a case where a voltage drop occurs even after a retry. In Figure 22, it is assumed that the range is switched from not P to P. The processing from time x60 to time x64 is the same as the processing from time x40 to time x44 in Figure 20. At time x65, if the motor voltage Vm falls below the voltage determination threshold Vth even during a retry, the retry flag is turned on.

At time x66, when the current-on status ST3 in the retry ends, the retry flag is on, so the retry flag is turned off and the retry counter is incremented. Here, if the count determination threshold Cth is 2, a second retry is not performed, the pre-switch preparation completion flag is turned on, and range switching is performed in normal two phases. The processing after time x66 is substantially the same as the processing after time x3 in FIG. 12.

In this embodiment, if there is a risk of the pre-switching preparation process failing due to a voltage drop during the pre-switching preparation process, the pre-switching preparation process is retried. Also, if the vibration does not converge in the energization status ST1, when the energization status is switched to ST2 or ST3, there is a risk that the opposing state will not change to two phases, two teeth, or one phase, one tooth, for example, due to a recess being opposed, so the pre-switching preparation is retried. Furthermore, if the amplitude A3 is greater than the amplitude judgment threshold Ath3 even after the energization hold time Xh3 has elapsed since the start of the energization status ST3 as the pre-switching preparation process, and the rotor 103 is not in a specified opposing state, the pre-switching preparation process is retried. This makes it possible to start range switching in a normal two-phase opposing state.

In this embodiment, if the retry condition is met in the pre-switching preparation process, the pre-switching preparation process is performed again. The control unit 50 determines that the retry condition is met if the amplitudes A1, A3 of the motor rotation angle when the current holding times Xh1, Xh3 have elapsed are greater than the amplitude judgment thresholds Ath1, Ath3 in at least one of the current-on status ST1 and current-on status ST3. The control unit 50 also determines that the retry condition is met if the motor voltage Vm or motor current Im becomes smaller than the judgment threshold during pre-start switching preparation. This can improve the accuracy of the pre-switching preparation process.

When the number of retries is equal to or greater than the determined number, the drive control unit 55 starts normal two-phase drive. This allows the motor 10 to start driving even when there is a large amount of vibration.

The ECU 40 is applied to a shift-by-wire system, and when the number of retries is equal to or greater than the number of judged retries and the retry condition is met, it allows switching from a range other than the P range to the P range by normal two-phase drive, and prohibits switching from the P range to a range other than the P range. This allows the shift range to be switched appropriately. It also provides the same effects as the above embodiment.

Sixth Embodiment
23 to 27 show the sixth embodiment. In the above-described embodiments, when a request to switch the shift range is made, a pre-switching preparation process is performed. In this embodiment, however, the pre-switching preparation process is performed in advance before a range switching request is made.

The startup process of this embodiment will be described based on the flowchart in FIG. 23. This process is executed when a vehicle start switch, such as an ignition switch, is turned on. In S401, the control unit 50 determines whether or not the initial drive has been completed. The initial drive process is a current application process for matching the relative positions of the encoder 13 and the rotor 103. If it is determined that the initial drive has not been completed (S401: NO), this determination process is repeated. If it is determined that the initial drive has been completed (S401: YES), the process proceeds to S402.

The process of S402 is the same as the process of S101 in FIG. 11. If it is determined that a one-phase break has not been detected (S402: NO), the process is skipped. If it is determined that a one-phase break has been detected (S402: YES), the process proceeds to S403.

S403 to S408 are pre-switching preparation processes similar to S103 to S108 in FIG. 11. When the pre-switching preparation process is completed, the control unit 50 turns on the pre-switching preparation completion flag in S409, transitions to standby mode in S410, and ends this process. In this embodiment, the encoder count value when the pre-switching preparation process is completed is stored as an initial value ENi in a storage unit such as a RAM (not shown).

The range switching process of this embodiment will be described based on the flowchart in FIG. 24. The processes of S501 and S502 are similar to the processes of S101 and S102 in FIG. 11. If it is determined that there is a switching request (S502: YES), the process proceeds to S505, and if it is determined that there is no switching request (S502: NO), the process proceeds to S503.

In S503, the control unit 50 determines whether the rotation amount ΔEN, which is the difference between the current encoder count value EN and the initial value ENi, is 0. If it is determined that the rotation amount ΔEN is 0 (S503: YES), that is, if the rotor 103 has not moved since the pre-switching preparation process was completed, the subsequent processes are skipped. If it is determined that the rotation amount ΔEN is not 0 (S503: NO), that is, if the rotor 103 has moved since the pre-switching preparation was completed, the process proceeds to S504 and the pre-switching preparation completion flag is turned off.

If it is determined that a range switching request has been made (S502: YES), the control unit 50 proceeds to S505, where it determines whether the pre-switching preparation complete flag is on. If it is determined that the pre-switching preparation complete flag is on (S505: YES), it proceeds to S516. If it is determined that the pre-switching preparation complete flag is off (S505: NO), it proceeds to S506.

In S506, the control unit 50 determines whether the rotation amount ΔEN is smaller than the rotation amount determination threshold ENth. The rotation amount determination threshold ENth is a value corresponding to the rotation amount when one current-carrying phase is switched, and is, for example, two counts of the encoder count value. If it is determined that the rotation amount ΔEN is smaller than the rotation amount determination threshold ENth (S507: YES), the process proceeds to S507. If it is determined that the rotation amount ΔEN is equal to or greater than the rotation amount determination threshold ENth (S507: NO), the process proceeds to S509.

The processes of S508 and S509 are the same as those of S107 and S108 in FIG. 11, and energization is performed in energization status ST3 for energization hold time Xh3. If it is determined in energization status ST3 that energization hold time Xh3 has elapsed (S508: YES), the process proceeds to S515.

The processing of S509 to S514 is the same as the processing of S103 to S108 in FIG. 11. If the rotation amount ΔEN is equal to or greater than the rotation amount determination threshold ENth, the pre-switch preparation processing is performed by switching the current status to ST1, ST2, and ST3. If it is determined in the current status ST3 that the current hold time Xh3 has elapsed (S514: YES), the process proceeds to S515.

The processing of S515 to S517 is the same as the processing of S109 to S111 in FIG. 11, and range switching is performed in normal two phases. If it is determined that range switching is complete (S517: YES), the process proceeds to S518, and pre-switching preparation processing is performed. In S518, pre-switching preparation processing is performed by switching between the energization status ST1, ST2, and ST3, as in S509 to S515. After the energization hold time Xh3 has elapsed in energization status ST3, the pre-switching preparation completion flag is turned on, and the standby mode is entered in S519. In addition, the encoder count value EN at the time pre-switching preparation is completed is retained as the initial value ENi.

The range switching process of this embodiment will be described based on the time charts of Figures 25 to 27. As shown in Figure 25, when the IG is turned on at time x70 and one-phase disconnection is detected by an initial diagnosis or the like, the current-carrying phase is switched in the order of current-carrying status ST1, ST2, and ST3 as pre-switching preparation process from time x72 when the initial drive ends. At time x73 when the pre-switching preparation process is completed, the pre-switching preparation completion flag is turned on and the standby mode is entered.

In the example of FIG. 25, the rotor 103 is not moving during standby, and the pre-switch preparation complete flag remains on. When a shift range switching request is input at time x74, the pre-switch preparation complete flag is on, so range switching is performed from this state using feedback control using normal two phases.

At time x75, when the target attainment judgment range is reached, stop control is performed. When the stop control ends at time x76, pre-switch preparation processing is performed in preparation for the next range switching. Since the rotation direction will be reversed in the next range switching, if there is a U-phase break, current is applied in the order of V-phase → VW-phase → W-phase. At time x77 when the pre-switch preparation processing ends, the pre-switch preparation complete flag is turned on and the mode transitions to standby mode.

In FIG. 26, the processing from time x80 to time x83 is the same as the processing from time x70 to time x73 in FIG. 25. At time x84, when the rotor 103 moves from the stop position when pre-switching preparation is completed due to, for example, vibration, the pre-switching preparation completion flag is turned off.

When a shift range switching request is input at time x85, the pre-switch preparation completion flag is off, so pre-switch preparation processing is performed again. In the example of FIG. 26, the rotation amount ΔEN from pre-switch preparation completion is smaller than the rotation amount determination threshold ENth, so as pre-switch preparation processing, V-phase current is applied if only current flow status ST3 is present, i.e., forward rotation with U-phase disconnection.

When the pre-switch preparation process is completed at time x86, the pre-switch preparation completion flag is turned on, and range switching is performed with feedback control using the two normal phases. The process after time x86 is the same as the process after time x74 in FIG. 25.

In FIG. 27, the processing from time x90 to time x93 is the same as the processing from x70 to x73 in FIG. 25. At time x94, when the rotor 103 moves from the stop position when pre-switching preparation is completed due to vibration or the like, the pre-switching preparation completion flag is turned off.

When a shift range switching request is input at time x95, the pre-switch preparation completion flag is off, so the pre-switch preparation process is performed again. In the example of FIG. 27, the rotation amount ΔEN from the pre-switch preparation completion is equal to or greater than the rotation amount determination threshold ENth, so the energized phases are switched in the order of energization status ST1, ST2, ST3, as in the pre-switch preparation process from time x92 to time x93, etc.

When the pre-switch preparation process is completed at time x96, the pre-switch preparation completion flag is turned on, and range switching is performed with feedback control using the two normal phases. The process after time x96 is the same as the process after time x74 in FIG. 25.

In this embodiment, by performing pre-switching preparation processing after the initial drive is completed and when the range switching is completed, the time required for range switching can be reduced compared to when pre-switching preparation processing is performed after a shift request.

In addition, when pre-switch preparation processing is performed in advance, there is a risk that the rotor 103 may move due to vibration or the like before a shift range switching request is input, which may change the opposing state between the stator 101 and the rotor 103. Therefore, if the rotor 103 moves after the pre-switch preparation processing is completed, the pre-switch preparation processing is performed again before the range switching.

If the amount of rotation of the rotor 103 after completion of pre-switching preparation is small and the current-carrying status ST3 can return to the opposing state at the time of completion of pre-switching preparation, the time required for the pre-switching preparation process can be shortened by performing the pre-switching preparation process only at current-carrying status ST3, compared to when current is applied from current-carrying status ST1. Also, if the amount of rotation ΔEN of the rotor 103 is equal to or greater than the rotation amount determination threshold ENth, range switching can be started from a predetermined opposing state by applying current to current-carrying statuses ST1 to ST3.

Here, the response time is the time from the input of the shift range switching request to the start of the stop control, the response time when the rotor 103 does not move from the completion of pre-switching preparation to the input of the shift range switching request is Xr1, the response time when the rotation amount ΔEN until the input of the shift range switching request is smaller than the rotation amount determination threshold ENth is Xr2, and the response time when the rotation amount ΔEN until the input of the shift range switching request is equal to or greater than the rotation amount determination threshold ENth is Xr3, where Xr1<Xr2<Xr3.

In this embodiment, when a wire breakage fault occurs in one of the three phases and normal two-phase drive is performed to drive the motor using the two normal phases, the drive control unit 55 performs pre-switching preparation processing to energize the energized phase after energizing it in a different energization pattern from the energization to the energized phase at the start of normal two-phase drive at least one of the time of system startup and after the motor 10 is stopped. This allows for improved responsiveness compared to when pre-switching preparation processing is performed at the start of motor 10 startup.

If the motor 10 rotates after the pre-switching preparation process is completed and before the motor 10 starts to drive, the pre-switching preparation process is performed again, and then normal two-phase drive is performed. As a result, if the rotor 103 moves due to vibration or the like between the completion of the pre-switching preparation process and the start of the motor drive, the pre-switching preparation process is performed again, making it possible to start normal two-phase drive from the appropriate opposing state.

In addition, if the rotation amount ΔEN of the motor 10 from the completion of the pre-switching preparation process to the start of driving the motor 10 is smaller than the rotation amount judgment threshold ENth, energization to phases other than the energized phase is omitted in the pre-switching preparation process before the start of motor driving. This makes it possible to shorten the pre-switching preparation process time before the start of motor driving. Also, the same effects as the above embodiment are achieved.

In the embodiment, the encoder 13 corresponds to the "rotational position sensor", the encoder count value corresponds to the "detection value of the rotational position sensor", and the ECU 40 corresponds to the "motor control device". In addition, the pre-switching preparation process corresponds to the "pre-start preparation process", the energization status ST1 corresponds to the "first energization process", the energization status ST2 corresponds to the "second energization process", the energization status ST3 corresponds to the "third energization process", and the energization phase in the energization status ST3 corresponds to the "energization retention phase".

Other Embodiments
In the first to sixth embodiments, the processing of each embodiment can be implemented in an appropriate combination, for example, by varying the power retention time according to the ambient temperature regardless of the timing of the pre-switching preparation process, by extending the power status before performing a retry, and by allowing P-in and prohibiting P-out if a timeout occurs.

In the above embodiment, the pre-energization preparation process switches the energized phase in the order of energization status ST1, ST2, and ST3. In other embodiments, one of the energization statuses ST1 and ST2 may be omitted.

In the above embodiment, the rotation detection unit is an encoder. In other embodiments, a sensor capable of detecting the rotation position other than an encoder, such as a resolver, may be used. In the above embodiment, the motor is a switched reluctance motor. In other embodiments, the motor may be other than a switched reluctance motor, such as a DC brushless motor. The number of phases of the motor winding may be four or more.

In the above embodiment, the detent plate has two valleys. In other embodiments, the number of valleys is not limited to two, and for example, four valleys corresponding to the P, R, N, and D ranges may be formed. In addition, the detent mechanism, parking lock mechanism, etc. may be different from those in the above embodiment.

In the above embodiment, the motor control device is applied to a shift-by-wire system. In other embodiments, the motor control device may be applied to an in-vehicle system other than a shift-by-wire system, or a motor drive system other than an in-vehicle system.

The present invention may be characterized as "the motor control device according to any one of claims 1 to 4, in which the control unit determines that the retry condition is met when the voltage or current becomes smaller than a determination threshold during the pre-start preparation process," and "the motor control device according to any one of claims 1 to 5, in which the drive control unit starts the normal two-phase drive when the number of retries is equal to or greater than the determination number."

The control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more dedicated computers configured by combining a processor and a memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by a computer. As described above, the present invention is not limited to the above embodiment, and can be implemented in various forms within the scope of the invention.

1 . . Shift-by-wire system 10 . . Motor 11 . . Motor winding 40 . . ECU (motor control device)
41: Drive circuit 411 to 413: Switching elements 50: Control unit 52: Abnormality determination unit 55: Drive control unit

Claims (7)

A motor control device for controlling the driving of a motor (10) having a three-phase motor winding (11), comprising:
A drive circuit (41) having switching elements (411 to 413) for switching on and off the current supply to each phase of the motor winding;
a control unit (50) having a drive control unit (55) that controls the on/off operation of the switching element by feedback control based on a detection value of a rotational position sensor (13) that detects the rotational position of the motor, and an abnormality determination unit (52) that determines a breakage fault in the motor winding;
Equipped with
when a disconnection fault occurs in one of three phases and normal two-phase drive is performed by using two normal phases to drive the motor, the drive control unit performs a pre-start preparation process of energizing the energization-holding phase after energizing the energization-holding phase in a pattern different from the energization pattern to the energized phase that is the energized phase at the start of the normal two-phase drive,
A motor control device that performs the pre-start preparation process again when a retry condition is satisfied in the pre-start preparation process. The motor control device according to claim 1, wherein the drive control unit switches the energization phase in the pre-start preparation process in the order of a first energization process for energizing phase 1 of the normal phase, a second energization process for energizing phase 2 of the normal phase, and a third energization process for energizing the energization-maintaining phase of phase 1. The energizing phase in the pre-start preparation process is set according to the disconnection phase and the rotation direction of the motor,
3. The motor control device according to claim 2, wherein the energized phase of the first energization process is a phase that is energized before the disconnection phase in terms of an energization phase switching sequence. The motor control device according to claim 2 or 3, wherein the control unit determines that the retry condition is satisfied when the amplitude of the motor rotation angle when the current holding time has elapsed is greater than an amplitude determination threshold in at least one of the first current supply process and the third current supply process. The motor control device according to claim 1 or 2, wherein the control unit determines that the retry condition is met if the voltage or current becomes smaller than a determination threshold during the pre-start preparation process. The motor control device according to claim 1 or 2, wherein the drive control unit starts the normal two-phase drive when the number of retries is equal to or greater than the determined number. Applied to a shift-by-wire system (1),
7. The motor control device according to claim 6, wherein when the number of retries is equal to or greater than the judgment number and the retry condition is satisfied, switching from a range other than the P range to the P range by the normal two-phase drive is permitted and switching from the P range to a range other than the P range is prohibited.

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