Motor control device, motor unit, motor control method

Abstract

The motor control device, motor unit, and motor control method of the present application can reduce the situation in which the behavior of a motor becomes unstable when the rotational speed of the motor is reduced. The motor control device has a plurality of sensors that detect the rotational position of a rotor and output a position detection signal, a rotational speed determination section that determines whether the rotational speed of the brushless motor is below a prescribed threshold value based on the position detection signal, and a motor control section, and a conduction control section provided in the motor control section uses different sensor signals for the sensor signals that trigger the conduction timing of each phase in a first mode and a second mode, the conduction timing of the second phase is advanced relative to the timing at which the position detection signal of the first sensor becomes on in the first mode, and the conduction timing of the second phase is delayed relative to the timing at which the position detection signal of the first sensor becomes on in the second mode.

Description

TECHNICAL FIELD

[0001] The present application relates to a motor control device, a motor unit, and a motor control method. BACKGROUND

[0002] A brushless motor includes a stator having coils U, V, and W of three phases, and a rotor having a permanent magnet for excitation, and is driven by energization control of the stator according to a rotational position of the rotor. The rotational position of the rotor is acquired by detecting a position of a magnetic pole of the rotor or a position of a sensor magnet that rotates together with the rotor, for example, using a plurality of Hall sensors.

[0003] The energization timing of each phase of the brushless motor is based on a detection signal obtained from each of the Hall sensors, and a count value is calculated using a timer in a microcomputer. When the time (counting is completed), a voltage is applied to the coils in accordance with the energization timing based on the count value. From the viewpoint of improving the output of the motor, such control of the energization timing of each phase of the brushless motor is advanced angle control.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Laid-Open No. 2018-133911 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, if the state becomes the restricted state sharply from the state in which the motor is driven normally at a certain motor speed, the motor speed decreases (decelerates). In this case, since the motor speed decreases, the time interval for position detection by the Hall sensor becomes longer (the input of the detection signal is delayed). Then, as the time interval for position detection becomes longer (the timing of the input of the detection signal is delayed), the error from the energization timing becomes larger, and thus the energization timing is shifted (becomes early) with respect to the actual rotor position. In addition, a phenomenon in which the position of the rotor is lost occurs. Therefore, a voltage is applied at an excessively advanced energization timing, and thus oscillation occurs, and thus the behavior of the motor becomes unstable.

[0009] The present application is made in view of such a situation, and aims to provide a motor control device, a motor unit, and a motor control method that can reduce the situation in which the behavior of the motor becomes unstable at the time of deceleration of the motor speed.

[0010] TECHNICAL MEANS FOR SOLVING THE PROBLEMS

[0011] To solve the problem, one embodiment of the present application is a motor control device that, in a brushless motor in which coils having a plurality of phases are energized to perform rotation control of a rotor, has: a plurality of sensors that detect a rotational position of the rotor and output a position detection signal; a rotation speed determination section that determines whether or not a rotation speed of the brushless motor is below a prescribed threshold value on the basis of the position detection signal; and a motor control section that can select a first mode selected when the rotation speed of the brushless motor exceeds the threshold value and a second mode selected when the rotation speed of the brushless motor becomes below the threshold value, the motor control section having an energization control section that energizes the plurality of phases of the coils at prescribed energization timings set on the basis of the position detection signal of each of the plurality of sensors, the energization control section being configured so that, in the first mode, when a first phase among the plurality of phases is energized at a prescribed energization timing set on the basis of the position detection signal of a first sensor among the plurality of sensors, in the second mode, a second phase among the plurality of phases is energized at a prescribed energization timing set on the basis of the position detection signal of the first sensor, in the first mode, the energization timing of the second phase is advanced relative to a timing at which the position detection signal of the first sensor becomes on, and in the second mode, the energization timing of the second phase is delayed relative to the timing at which the position detection signal of the first sensor becomes on.

[0012] Effects of the Invention

[0013] As described above, according to the present application, it is possible to reduce cases in which the behavior of the motor becomes unstable at the time of deceleration of the rotation speed of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a drawing showing an example of a schematic configuration of a front glass 11 of a vehicle 10 to which a wiper device 12 including the motor control device of the present embodiment is mounted.

[0015] Figure 2 is a drawing showing an example of the appearance of a motor unit 19 in the present embodiment.

[0016] Figure 3 is a bottom view of the motor unit 19 in a state in which an under cover 28 is removed.

[0017] Figure 4 is a drawing showing an example of a schematic configuration of a control system of the wiper device 12 in the present embodiment.

[0018] Figure 5is a diagram showing an example of the outline configuration of the control section 54 in the embodiment.

[0019] Figure 6 is a timing chart illustrating the relationship between the position detection signal obtained from the rotation angle detection section and the energization timing of each of the U, V, and W phases in the advance angle control mode.

[0020] Figure 7 is a timing chart illustrating the relationship between the position detection signal obtained from the rotation angle detection section 39 and the energization timing of each of the U, V, and W phases in the delay angle control mode.

[0021] Figure 8 is a flowchart illustrating the operation of the motor control device 33.

[0022] Figure 9A is a diagram showing three-phase current waveforms in the case where the motor is restrained after deceleration from steady driving in the advance angle control mode.

[0023] Figure 9B is a diagram showing three-phase current waveforms in the case where the motor is decelerated from steady driving in the advance angle control mode.

[0024] Figure 10 is a diagram showing three-phase current waveforms in the case where the motor is restrained after deceleration from steady driving while using the function of switching from the advance angle control mode to the delay angle control mode.

[0025] Figure 11 is a diagram illustrating the restrained torque in the case where the advance angle control is performed at the time of deceleration and in the case where the delay angle control is performed at the time of deceleration.

[0026] [Explanation of Symbols]

[0027] 10: vehicle

[0028] 11: windshield

[0029] 12: wiper device

[0030] 13, 15: pivot

[0031] 14, 16: wiper arm

[0032] 17, 18: wiper blade

[0033] 19: motor unit

[0034] 20: power transmission mechanism

[0035] 21: stator

[0036] 21u, 21v, 21w: armature coil

[0037] 22: rotor

[0038] 22a: rotor shaft

[0039] 22b: permanent magnet

[0040] 22c: worm

[0041] 23: housing

[0042] 24: frame

[0043] 24a: opening portion

[0044] 25: worm wheel

[0045] 25a: gear

[0046] 26: output shaft

[0047] 27: reduction mechanism

[0048] 28: lower cover

[0049] 29: control substrate

[0050] 30: brushless motor

[0051] 33: motor control device

[0052] 37: wiper switch

[0053] 38: sensor magnet

[0054] 39: rotation angle detection portion

[0055] 40: vehicle speed sensor

[0056] 51: direct current power supply

[0057] 52: inverter

[0058] 52a, 52b, 52c, 52d, 52e, 52f: switching element

[0059] 53a, 53b, 53c, 53d, 53e, 53f: diode

[0060] 54: control portion

[0061] 61: position detection portion

[0062] 62: load determination portion

[0063] 63: wiper mode determination portion

[0064] 64: drive control portion

[0065] 600, 601, 602, 603, 605, 611, 612, 613, 614, 615, 616, 700, 701, 702, 703, 704, 705, 710, 711, 712, 713, 714, 715: symbols

[0066] 604, 610, 952: symbols (position detection signal)

[0067] 641: rotation speed determination section

[0068] 642: energization control section

[0069] 900, 960: section

[0070] 911, 951, 961: U phase (symbol)

[0071] 912, 962: V phase (symbol)

[0072] 913, 963: W phase (symbol)

[0073] 950: section (symbol)

[0074] V: travel speed (vehicle speed) DETAILED DESCRIPTION

[0075] Hereinafter, the embodiments of the application will be described by way of the embodiments of the application, but the following embodiments do not limit the application of the claims. In addition, the combination of features described in the embodiments is not necessarily all of the means for solving the application. Furthermore, in the drawings, the same symbols are sometimes attached to the same or similar parts and repeated description is omitted.

[0076] The motor control device of the present embodiment controls a brushless motor. Such a brushless motor can be any one of a brushless motor that causes a wiper arm to perform a swing operation, a brushless sunroof motor that causes a sunroof panel to perform an opening / closing operation, a brushless power window motor, and a brushless power seat motor, for example.

[0077] Hereinafter, the motor control device in the present embodiment will be described using drawings. Here, a case in which a brushless motor is used to cause a wiper arm to perform a swing operation will be described as an example.

[0078] Figure 1 is a drawing showing an example of a schematic structure of a windshield 11 of a vehicle 10 to which a wiper device 12 including the motor control device of the present embodiment is mounted.

[0079] As shown in Figure 1 , the vehicle 10 includes the windshield 11 and the wiper device 12.

[0080] The wiper unit 12 wipes the windshield 11.

[0081] The wiper assembly 12 includes: wiper arm 14, wiper arm 16; wiper blade 17, wiper blade 18; motor unit 19 and power transmission mechanism 20.

[0082] Wiper arm 14 swings around pivot 13. Wiper arm 16 swings around pivot 15.

[0083] Wiper blade 17 is mounted on the free end of wiper arm 14. Wiper blade 18 is mounted on the free end of wiper arm 16.

[0084] The motor unit 19 drives the wiper arms 14 and 16. In this embodiment, the power of the motor unit 19 is transmitted to the wiper arms 14 and 16 respectively via a power transmission mechanism 20 including a lever and a link.

[0085] Figure 2 This is a diagram showing an example of the appearance of the motor unit 19 in this embodiment. Figure 3 yes Figure 2 The diagram shows the bottom view of the motor unit 19 with the lower cover 28 removed.

[0086] like Figure 2 As shown, the exterior of the motor unit 19 mainly includes a housing 23 and a frame 24.

[0087] The housing 23 has a bottomed cylindrical shape. The frame 24 has a hollow shape. The frame 24 and the housing 23 are fixed together by fastening members not shown.

[0088] like Figure 3 As shown, the motor unit 19 includes: a brushless motor 30, a rotor shaft 22a, an opening 24a, a worm wheel 25, an output shaft 26, a reduction mechanism 27, a lower cover 28, a control board 29, a sensor magnet 38, and a motor control device 33.

[0089] The brushless motor 30 causes the wiper arms 14 and 16 to swing based on the control instructions of the motor control device 33.

[0090] For example, brushless motor 30 is a three-phase four-pole brushless motor.

[0091] The brushless motor 30 includes a stator 21 and a rotor 22.

[0092] The stator 21 is fixed to the inner periphery of the housing 23. The stator 21 includes three-phase armature coils 21u, 21v, 21w. The stator 21 is wound with the armature coils 21u, 21v, 21w. For example, the three-phase armature coils 21u, 21v, 21w are connected by a delta connection in which the neutral points at one end are connected. However, the connection is not limited to the delta connection, and can be a Y connection. In addition, the brushless motor 30 is a motor in which each of the armature coils 21u, 21v, 21w functions as both of a positive electrode and a negative electrode.

[0093] For example, the rotor 22 is provided inside the stator 21. The rotor 22 includes a rotor shaft 22a and four-pole permanent magnets 22b attached to the rotor shaft 22a. A plurality of bearings (not shown) are provided inside the housing 23, and the rotor shaft 22a is rotatably supported by the plurality of bearings.

[0094] Further, as shown in Figure 3 , the rotor 22 is an inner rotor type structure in which the rotor 22 is disposed inside the stator 21, but can be an outer rotor type structure in which the rotor 22 is disposed outside the stator 21.

[0095] Approximately half of the length direction of the rotor shaft 22a is disposed inside the housing 23, and the remaining approximately half is disposed inside the frame 24.

[0096] A deceleration mechanism 27 is formed in the outer periphery of the portion of the rotor shaft 22a that is disposed inside the frame 24. The deceleration mechanism 27 includes a worm 22c and a gear 25a.

[0097] The worm 22c is provided to the outer periphery of the rotor shaft 22a disposed inside the frame 24. The gear 25a is formed in the outer periphery of a worm wheel 25 provided inside the frame 24. The gear 25a is engaged with the worm 22c.

[0098] The worm wheel 25 is configured to rotate integrally with an output shaft 26. The deceleration mechanism 27 causes the rotation speed (output rotation speed) of the output shaft 26 to be lower than the rotation speed (input rotation speed) of the rotor 22 when transmitting the power of the rotor 22 to the output shaft 26. In addition, in Figure 2 , an axis hole of the frame 24 is not shown. The end portion of the output shaft 26 on the side opposite to the end portion to which the worm wheel 25 is fixed is exposed to the outside via the axis hole of the frame 24. As shown in Figure 1 , the portion of the output shaft 26 that is exposed to the outside of the frame 24 is connected to the power transmission mechanism 20.

[0099] An opening portion 24a is provided to the portion of the frame 24 on the side opposite to the axis hole. The opening portion 24a is formed in order to install the worm wheel 25 and the like inside the frame 24. A lower cover 28 is provided so as to plug the opening portion 24a. The lower cover 28 has a tray shape.

[0100] The control substrate 29 is disposed in a space surrounded by the lower cover 28 and the frame 24. As shown, for example, the control substrate 29 is mounted to the lower cover 28. A motor control device 33 that controls the brushless motor 30 is provided on the control substrate 29. Figure 2

[0101] The sensor magnet 38 is disposed in a portion of the rotor shaft 22a that is disposed inside the frame 24. The sensor magnet 38 rotates integrally with the rotor shaft 22a. The sensor magnet 38 is magnetized such that N poles and S poles are arranged alternately in the circumferential direction of the rotor shaft 22a.

[0102] Hereinafter, the motor control device 33 in the present embodiment will be described using the drawings.

[0103] Figure 4 is a diagram showing an example of the schematic configuration of the control system of the wiper device 12 in the present embodiment. The wiper device 12 includes a wiper switch 37, a rotation angle detection section 39, a vehicle speed sensor 40, and the motor control device 33.

[0104] The wiper switch 37 is disposed in the passenger compartment of the vehicle 10.

[0105] The wiper switch 37 is a switch that causes the wiper arm 14 and the wiper arm 16 to perform a swinging operation.

[0106] The wiper switch 37 can be switched to each of a low-speed operation mode in which the wiper arm 14 and the wiper arm 16 are caused to operate at a low speed (for example, a speed set in advance), a high-speed operation mode in which the wiper arm 14 and the wiper arm 16 are caused to operate at a higher speed than in the low-speed operation mode, and a stop mode in which the swinging operation of the wiper arm 14 and the wiper arm 16 is stopped.

[0107] The wiper switch 37 outputs an operation signal indicating the operation to the motor control device 33 by being operated by the driver. For example, the driver can switch the wiping speed of the wiper arm 14 and the wiper arm 16 by operating the wiper switch 37 based on the amount of rainfall, the amount of snowfall, or the like. When the amount of rainfall or the amount of snowfall is small, the driver can select the low-speed operation mode in which the wiper arm 14 and the wiper arm 16 are caused to operate at a low speed decided in advance by operating the wiper switch 37. In this case, the wiper switch 37 outputs a low-speed operation mode signal indicating the low-speed operation mode as the operation signal to the motor control device 33 based on the operation of selecting the low-speed operation mode by the driver.

[0108] ​On the other hand, when the amount of rainfall or snowfall is large, the driver can operate the wiper switch 37 to select a high-speed operation mode in which the wiper arms 14, 16 are caused to operate at a higher speed than the low speed. In this case, the wiper switch 37 outputs a high-speed operation mode signal indicating the high-speed operation mode to the motor control device 33 as an operation signal based on the operation of the driver selecting the high-speed operation mode.

[0109] In addition, in a case where the wiper switch 37 is operated by the driver to stop the swinging operation of the wiper arms 14, 16, the wiper switch 37 outputs a stop mode signal indicating the stop mode to the motor control device 33 as an operation signal.

[0110] The vehicle speed sensor 40 is provided to the vehicle 10. The vehicle speed sensor 40 measures the running speed (hereinafter, referred to as "vehicle speed") V of the vehicle 10. The vehicle speed sensor 40 outputs the measured vehicle speed V of the vehicle 10 to the motor control device 33.

[0111] The rotation angle detection section 39 detects a signal corresponding to the rotation of the rotor 22. For example, the rotation angle detection section 39 includes three Hall integrated circuits (ICs) (U-phase sensor, V-phase sensor, W-phase sensor) and is provided at positions that are 120 degrees apart from each other in a magnetic sense with the rotor shaft 22a as the center. The three Hall ICs respectively output pulse signals that are 120 degrees apart in phase to the motor control device 33 when the rotor 22 rotates. That is, the rotation angle detection section 39 generates a pulse signal based on the change in the magnetic pole of the sensor magnet 38 as the rotor 22 rotates and outputs the pulse signal to the motor control device 33.

[0112] The motor control device 33 includes an inverter 52 and a control section 54.

[0113] The inverter 52 includes six switching elements 52a to 52f connected in a bridge connection, and diodes 53a to 53f connected in reverse parallel between the collector and the emitter of each of the switching elements 52a to 52f. Each of the switching elements 52a to 52f is, for example, a Field Effect Transistor (FET) or an Insulated Gate Bipolar Transistor (IGBT). The gates of the six switching elements 52a to 52f connected in the bridge connection are connected to the control section 54.

[0114] The drain or source (collector or emitter) of the switching elements 52a to 52f is connected to the armature coil 21u, 21v, 21w via a delta connection. Thus, the six switching elements 52a to 52f perform switching operation based on drive signals (gate signals) output from the control section 54, and supply the power source voltage of the direct current power source 51 applied to the inverter 52 as a power supply signal to the armature coil 21u, 21v, 21w in the form of three-phase (U-phase, V-phase, W-phase) alternating voltage.

[0115] The control section 54 determines the rotational position of the rotor 22 based on the pulse signal supplied from the rotational angle detection section 39. In addition, the control section 54 detects the rotational speed of the rotor 22 based on the pulse signal.

[0116] Hereinafter, the following Figure 5 The control section 54 in the present embodiment will be described.

[0117] Figure 5 is a diagram showing an example of the outline structure of the control section 54 in the present embodiment.

[0118] The control section 54 includes a position detection section 61, a load determination section 62, a wiper mode determination section 63, and a drive control section 64.

[0119] The position detection section 61 detects the rotational position of the rotor 22 based on the pulse signal supplied from the rotational angle detection section 39. The position detection section 61 outputs the detected rotational position of the rotor 22 to the drive control section 64.

[0120] The load determination section 62 determines whether the load applied to the brushless motor is a high load.

[0121] For example, the load determination section 62 reads out the overload determination reference value of the output duty corresponding to the rotational speed of the rotor, by referring to determination data in which the output duty of the voltage applied to the motor and the overload determination reference value are associated, and determines whether the output duty of the voltage currently applied to the motor exceeds the overload determination reference value read out. Here, in the case where the current output duty exceeds the overload determination reference value, the load determination section 62 determines that the overload state. That is, the load determination section 62 determines that the load applied to the brushless motor is a high load. On the other hand, in the case where the current output duty does not exceed the overload determination reference value, the load determination section 62 determines that it is not a high load. Further, it can be configured that the determination data is stored in a storage section provided in the control section 54, and the load determination section 62 refers to the storage section.

[0122] In addition, the load determination section 62 can determine whether it is a high load based on the output duty, but the detection of the overload state can also use the output from the vehicle speed sensor 40.

[0123] In this case, the load determination portion 62 determines whether the vehicle speed V measured by the vehicle speed sensor 40 exceeds a predetermined value Vth. In the case where the vehicle speed V measured by the vehicle speed sensor 40 exceeds the predetermined value Vth, the load determination portion 62 determines that the load of the brushless motor 30 is a high load. The load determination portion 62 outputs a high load signal indicating the determination result to the wiper mode determination portion 63 in the case where it is determined that the load of the brushless motor 30 is a high load. The reason for this is that, when the vehicle speed V of the vehicle 10 increases, the amount of wind to the windshield 11 of the vehicle 10 increases, thereby hindering the movement of the wiper blades 17, 18 that wipe the windshield 11.

[0124] The wiper mode determination portion 63 determines whether the brushless motor 30 is driven in a low output mode, or in a high output mode, or whether the drive of the brushless motor 30 is stopped.

[0125] In the case where the low speed operation mode signal is acquired from the wiper switch 37, the wiper mode determination portion 63 determines that the brushless motor 30 is driven in a low output mode, and outputs a low output mode signal indicating the low output mode to the drive control portion 64.

[0126] In the case where the high speed operation mode signal is acquired from the wiper switch 37, the wiper mode determination portion 63 determines that the brushless motor 30 is driven in a high output mode, and outputs a high output mode signal indicating the high output mode to the drive control portion 64. In addition, in the case where the high load signal is acquired from the load determination portion 62, the wiper mode determination portion 63 determines that the brushless motor 30 is driven in a high output mode, and outputs a high output mode signal indicating the high output mode to the drive control portion 64.

[0127] In the case where the stop mode signal is acquired from the wiper switch 37, the wiper mode determination portion 63 determines that the drive of the brushless motor 30 is stopped, and outputs a stop signal indicating the stop of the drive of the brushless motor 30 to the drive control portion 64.

[0128] The drive control portion 64 includes a rotation speed determination portion 641 and a current supply control portion 642.

[0129] The rotation speed determination portion 641 determines whether the rotation speed of the brushless motor 30 is below a predetermined threshold value.

[0130] The threshold value can be, for example, a speed before a certain degree of motor lock. In the case where the speed before a certain degree of motor lock is used as the threshold value, the rotation speed determination portion 641 can grasp the possibility of motor lock, and the rotation speed of the motor is a speed slightly before the motor lock. The threshold value can be arbitrarily set.

[0131] The energization control section 642 energizes the three-phase armature coils 21u, 21v, 21w at a prescribed energization timing set based on the position detection signal output from the Hall IC of the rotation angle detection section 39. That is, the energization control section 642 counts up from the timing of the on or off of the position detection signal by means of a timer provided in the control section 54, and energizes the three-phase armature coils 21u, 21v, 21w at a prescribed timer count value. The timer count value is a value calculated from the record of the timing of the on or off of the position detection signal before one cycle in the rotation of the rotor 22. Thus, the energization control section 642 makes the energization timing variable in accordance with the rotation speed (rotational speed). The energization control section 642 performs advance angle control that energizes at an advance angle timing based on the position detection signal obtained from the Hall IC in the case where the rotation speed of the motor is a certain speed or is accelerating, and performs delay angle control that energizes at a delay angle timing based on the position detection signal obtained from the Hall IC before the motor stops in the case where the motor is decelerating.

[0132] Specifically, the energization control section 642 can select either the advance angle control mode (first mode) selected by the rotation speed determination section 641 in the case where the rotation speed of the brushless motor 30 exceeds a prescribed threshold value, or the delay angle control mode (second mode) selected in the case where the rotation speed of the brushless motor 30 is equal to or less than the prescribed threshold value.

[0133] The energization control section 642 energizes one phase (first phase) of the three-phase armature coils 21u, 21v, 21w at a prescribed energization timing set based on the position detection signal of one of the three Hall ICs (first sensor) in the advance angle control mode, and energizes a second phase different from the first phase of the three-phase armature coils 21u, 21v, 21w at a prescribed energization timing set based on the position detection signal of the first sensor in the delay angle control mode. Then, the energization control section 642 energizes in such a manner that the energization timing of the second phase is advanced with respect to the timing at which the position detection signal of the first sensor becomes on in the advance angle control mode, and the energization timing of the second phase is delayed with respect to the timing at which the position detection signal of the first sensor becomes on in the delay angle control mode.

[0134] Under general motor control, advance angle control that advances the energization timing in accordance with the rotational speed is performed with respect to the position of the rotor based on the position detection signal output from the Hall IC, but as described above, in the present embodiment, with respect to the position indicated by the position detection signal in the low speed region (at the time of deceleration), a control mode that delays the energization timing (delay angle) is used.

[0135] The delay angle described here is the timing of the electric angle delay based on the timing of obtaining the position detection signal.

[0136] Thus, according to the present embodiment, by performing the delay angle energization in the low speed region (at the time of deceleration), even if the input of the position detection signal is delayed at the time of deceleration, the actual rotor position can be made to be applied with voltage at a timing that is not excessively advanced.

[0137] Further, the energization control section 642 can also have a start-up mode in which the motor is driven from the state in which the rotor is substantially stopped and the position of the rotor cannot be estimated. In the start-up mode, the reference energization in which energization is performed and driving is performed at the timing that is synchronized with the position detection signal of the Hall IC can also be performed.

[0138] The energization control section 642 switches from the advance angle control mode to the delay angle control mode in the case where the brushless motor 30 is high load, and the rotational speed of the brushless motor 30 is below a threshold value and the brushless motor 30 is driven in the advance angle control mode. By switching to the delay angle control mode, delay angle control can be performed.

[0139] Use Figure 6 , Figure 7 The specific example of the control performed by the energization control section 642 will be described.

[0140] Figure 6 , Figure 7 is a timing chart that illustrates the relationship of the position detection signal obtained from the Hall IC (U-phase sensor, V-phase sensor, W-phase sensor) of the rotational angle detection section 39, and the timing of energization to each phase of the armature coil 21u (U-phase), armature coil 21v (V-phase), armature coil 21w (W-phase).

[0141] Figure 6is a timing chart illustrating the relationship between the position detection signal and the energization timing in the case where the advance angle control as in the past is performed at a certain speed or during acceleration of the brushless motor 30, that is, in the advance angle control mode. At the electric angle 0°, when the position detection signal of the U-phase sensor becomes ON (symbol 600), the energization control section 642 starts counting using the timer, and after counting of a prescribed timer count value, ends the counting, and at the same time of the end of the counting, starts energization of the negative voltage to the W-phase (symbol 601). Also, at the electric angle 120°, when the position detection signal of the V-phase sensor becomes ON (symbol 602), the energization control section 642 starts counting using the timer, and after counting of a prescribed timer count value, ends the counting, and at the same time of the end of the counting, starts energization of the negative voltage to the U-phase (symbol 603). Also, at the electric angle 240°, when the position detection signal of the W-phase sensor becomes ON (symbol 604), the energization control section 642 starts counting using the timer, and after counting of a prescribed timer count value, ends the counting, and at the same time of the end of the counting, starts energization of the negative voltage to the V-phase (symbol 605).

[0142] Also, at the electric angle 180°, when the position detection signal of the U-phase sensor becomes OFF (symbol 610), the energization control section 642 starts counting using the timer, and after counting of a prescribed timer count value, ends the counting, and at the same time of the end of the counting, starts energization of the positive voltage to the W-phase (symbol 611). Also, at the electric angle 300°, when the position detection signal of the V-phase sensor becomes OFF (symbol 612), the energization control section 642 starts counting using the timer, and after counting of a prescribed timer count value, ends the counting, and at the same time of the end of the counting, starts energization of the positive voltage to the U-phase (symbol 613). Also, at the electric angle 60°, when the position detection signal of the W-phase sensor becomes OFF (symbol 614), the energization control section 642 starts counting using the timer, and after counting of a prescribed timer count value, ends the counting, and at the same time of the end of the counting, starts energization of the positive voltage to the V-phase (symbol 615).

[0143] Thus, the energization timing to the U-phase is advanced with respect to the timing when the U-phase sensor becomes ON or OFF. Also, the energization timing to the V-phase is advanced with respect to the timing when the V-phase sensor becomes ON or OFF. Also, the energization timing to the W-phase is advanced with respect to the timing when the W-phase sensor becomes ON or OFF.

[0144] Next, using Figure 6 A case where the advance angle control is continued even if the rotational speed of the brushless motor 30 becomes below a prescribed threshold value is described.

[0145] When the position detection signal of the W-phase sensor becomes ON (symbol 604), the energization control section 642 starts counting using a timer. The timer count value used at this time is calculated from data before one cycle, so when the rotational speed of the brushless motor 30 becomes below a prescribed threshold value during this period, the counting ends before the rotor 22 reaches the supposed angle, and the energization timing to the V-phase becomes a timing that is excessively advanced (symbol 616).

[0146] Such a shift in energization timing can occur not only when the position detection signal of the W-phase sensor becomes ON, but also at a timing when the position detection signal becomes OFF.

[0147] In addition, such a shift in energization timing can occur not only in the W-phase, but also in any of the V-phase and U-phase.

[0148] In contrast, in the present embodiment, the energization control section 642 performs delay angle control at the time of deceleration.

[0149] Figure 7 is a timing chart that illustrates the relationship between the position detection signal and the energization timing when the energization control section 642 performs delay angle control at the time of deceleration of the brushless motor 30, that is, in the delay angle control mode.

[0150] At an electric angle of 0°, when the position detection signal of the U-phase sensor becomes ON (symbol 700), the energization control section 642 starts counting using a timer, and after counting of a prescribed timer count value, ends the counting, and at the same time as the counting ends, starts energization of a positive voltage to the U-phase (symbol 701). At an electric angle of 120°, when the position detection signal of the V-phase sensor becomes ON (symbol 702), the energization control section 642 starts counting using a timer, and after counting of a prescribed timer count value, ends the counting, and at the same time as the counting ends, starts energization of a positive voltage to the V-phase (symbol 703). At an electric angle of 240°, when the position detection signal of the W-phase sensor becomes ON (symbol 704), the energization control section 642 starts counting using a timer, and after counting of a prescribed timer count value, ends the counting, and at the same time as the counting ends, starts energization of a positive voltage to the W-phase (symbol 705).

[0151] In addition, at the electric angle 180°, when the position detection signal of the U-phase sensor becomes off (symbol 710), the energization control section 642 starts counting using the timer, and after counting of a prescribed timer count value, ends the counting, and at the same time as the end of the counting, starts energization of negative voltage to the U-phase (symbol 711). In addition, at the electric angle 300°, when the position detection signal of the V-phase sensor becomes off (symbol 712), the energization control section 642 starts counting using the timer, and after counting of a prescribed timer count value, ends the counting, and at the same time as the end of the counting, starts energization of negative voltage to the V-phase (symbol 713). In addition, at the electric angle 60°, when the position detection signal of the W-phase sensor becomes off (symbol 714), the energization control section 642 starts counting using the timer, and after counting of a prescribed timer count value, ends the counting, and at the same time as the end of the counting, starts energization of negative voltage to the W-phase (symbol 715).

[0152] Thus, the energization timing to the U-phase is delayed with respect to the timing at which the U-phase sensor becomes on or off. In addition, the energization timing to the V-phase is delayed with respect to the timing at which the V-phase sensor becomes on or off. In addition, the energization timing to the W-phase is delayed with respect to the timing at which the W-phase sensor becomes on or off.

[0153] Here, the timer count value in the delay angle control mode is, as with the advance angle control mode, a value calculated from the record of the timing at which on or off occurs based on the position detection signal of the previous cycle.

[0154] Thus, in the advance angle control, counting is performed from the timing of the on or off of the position detection signal of the sensor (Hall IC) different from the sensor (Hall IC) that outputs the reference of the advance angle. For example, counting is performed from the timing of the on or off of the position detection signal (symbol 610) of the sensor (U-phase sensor) different from the sensor (W-phase sensor) that outputs the reference of the advance angle (symbol 604), and based on the result of the counting, energization to the W-phase that becomes on or off is performed. That is, in the energization control of the W-phase, the position detection signal from the sensor (in this case, the U-phase sensor) of the different phase from the W-phase is used as the starting point of the counting. Similarly, in the energization control of the U-phase, the position detection signal from the sensor (in this case, the V-phase sensor) of the different phase from the U-phase is used as the starting point of the counting, and in the energization control of the V-phase, the position detection signal from the sensor (in this case, the W-phase sensor) of the different phase from the V-phase is used as the starting point of the counting. Thus, assuming the case where the advance angle control is performed at the time of deceleration, the timer count value at one cycle before the position detection signal is used, and the advance angle control is performed at the next cycle of the position detection signal, the rotational angle of the rotor only rotates an angle less than the electrical angle even if the time based on the electrical angle for the timer count elapses. Thus, the sensor signal input (for example, the position detection signal (symbol 604)) that is the reference of the advance angle is delayed from the timing assumed, and thus the timing (for example, symbol 611) of the energization by the advance angle is open from the timing of the sensor signal input (for example, the position detection signal (symbol 604)), and as a result, an over-advance angle state is caused.

[0155] On the other hand, according to the present embodiment, since the delay angle control is performed at the time of deceleration, the energization can be waited until the next position detection signal enters. In other words, in the deceleration control, counting is performed from the timing of the on or off of the position detection signal of the sensor (Hall IC) that is the same as the sensor (Hall IC) that outputs the reference of the delay angle. Thus, the sensor signal that is used as the trigger of the energization timing in the advance angle control is different from the sensor signal that is used as the trigger of the energization timing in the delay angle control. Thus, in the case where the control unit 54 detects a decrease in the rotational speed based on the position detection signal obtained the time before last and the position detection signal obtained last time (the interval of the detection times of the position detection signals becomes wide), the timing of the position detection signal obtained this time can be used as the reference, and the energization is performed at the timing that becomes the delay angle in the electrical angle. Thus, even if the rotational speed of the motor changes in a decreasing manner at the time of deceleration, the control can be performed based on the information of the updated rotational position. Thus, even in the deceleration state of the motor, the shift of the energization timing can be moderated, and thus the oscillation can be prevented.

[0156] Further, according to the structure, since the electric angle is delayed at the time of deceleration, it is necessary to start energization after the position detection signal of the Hall IC is input even at the time of deceleration of the motor. Thus, at the time point when the position detection signal of the Hall IC is input, the rotor position information calculated based on the timer count value is updated, and even at the time of deceleration of the motor, the accurate rotor position can be grasped, and thus the oscillation can be prevented, and the behavior of the motor is stabilized.

[0157] Further, at the time of the delay angle control, as the range of the electric angle of the delay, it is desirable to set 0° < θ < 30° between in the electric angle based on the position detection signal. If 30° < θ < 60° is assumed, there is a risk that the shift of the energization time caused by the deceleration of the motor cannot be suppressed.

[0158] Next, Figure 8 is a flowchart illustrating the operation of the control section 54.

[0159] The control section 54 determines whether the output duty exceeds the overload determination reference value by the load determination section 62 (step S101). In the case where the output duty exceeds the overload determination reference value (step S102 - YES), the control section 54 determines whether the rotation speed of the brushless motor 30 is below a prescribed threshold value by the rotation speed determination section 64 (step S102).

[0160] Then, in the case where the rotation speed of the brushless motor 30 is below the threshold value (step S102 - YES), the control section 54 shifts to the delay angle control mode.

[0161] For example, in the case where the rotation speed of the motor is decelerated, and particularly in the case where the rotation speed of the motor is below the threshold value, it can be determined that the motor is in a state just before locking, and thus the delay of the current is in a state close to 0 with respect to the applied voltage. In this situation, even if the delay angle control is performed, there is almost no difference in the delay of the current with respect to the applied voltage compared to the case where the advance angle control is performed. Therefore, even if the delay angle control is used at the time of deceleration, there is no influence on the control.

[0162] On the other hand, in a case where the output duty does not exceed the overload determination reference value (step S101-NO), or in a case where the motor rotation speed is not below the threshold value (step S102-NO), the control section 54 shifts to the advance angle control mode. Thus, in a case where the motor is not overloaded, or in a case where the motor is decelerated, the control is performed in the advance angle control mode, and thus the desired motor output can be obtained. By providing not only the step S102 but also the step S101, the condition for shifting to the retard angle control mode is limited, and in a case where the retard angle control mode is not needed, the advance angle control mode using the characteristics in which the torque or the rotation speed of the motor can be increased can be set. For example, near the reverse position of the wiper blade, the motor is decelerated, but if the duty does not exceed the overload determination reference value, the advance angle control mode is maintained.

[0163] Figure 9A is a graph showing the three-phase current waveforms in a case where the constraint is performed after the deceleration from the steady driving in the advance angle control mode.

[0164] In Figure 9A , the vertical axis represents the current value, and the horizontal axis represents the time.

[0165] In a case where the motor is decelerated, as shown in the section 900, the currents of the U phase (symbol 911), the V phase (symbol 912), and the W phase (symbol 913) are all formed as waveforms in a collapsed state, indicating that the driving state of the motor is unstable.

[0166] Figure 9B is a graph showing the three-phase current waveforms and the position detection signal of the V phase sensor in a case where the deceleration state is shifted from the steady driving in the advance angle control mode.

[0167] In Figure 9B , the vertical axis represents the current value, and the horizontal axis represents the electric angle.

[0168] In the section (symbol 950), at the timing at which the peak of the current value in the U phase (symbol 951) is overlapped, the position detection signal (symbol 952) of the V phase sensor is turned on in the steady driving, and thus the timing of the driving current applied to the U phase and the position detection signal detected based on the driving current and by the rotation of the rotor are substantially coincident, and it can be said that the driving state is stable.

[0169] However, in the deceleration, as shown in the section 960, at the timing deviated from the peak of the current value in the U phase, the position detection signal of the V phase sensor is turned on, and thus the timing of the driving current applied to the U phase and the position detection signal detected based on the driving current and by the rotation of the rotor are deviated. Thus, it can be said that the driving state is unstable.

[0170] Here, Figure 10is a graph showing three-phase current waveforms in a case where the motor is restrained after deceleration from steady driving while using a function of switching from the advance angle control mode to the retard angle control mode.

[0171] In Figure 10 In this graph, the vertical axis represents the current value, and the horizontal axis represents the time.

[0172] When the motor is decelerated, in a case where energization is performed by the retard angle control mode, as shown in section 960, the currents of the U phase (symbol 961), the V phase (symbol 962), and the W phase (symbol 963) are in a relationship that can be said to be substantially similar as waveforms, and since they do not become disordered waveforms, it is indicated that the driving state of the motor is stable.

[0173] Figure 11 is a graph that explains the restrained torque in a case where the advance angle control is performed at the time of deceleration and in a case where the retard angle control is performed at the time of deceleration. The restrained torque is the value of the torque at the time of locking of the motor.

[0174] The vertical axis represents the torque, and the horizontal axis represents which of the advance angle control or the retard angle control. The vertical bar represents the range of the overall value, the upper end of the vertical bar represents the maximum value, and the lower end of the vertical bar represents the minimum value. The point between the upper end and the lower end of the vertical bar represents the average value obtained by taking the overall value as an object.

[0175] In the advance angle control, since the difference between the maximum value and the minimum value in the overall value is large, it is indicated that the torque is unstable. Since the torque is unstable, a case where the torque at the time of locking of the motor is low or a case where it is high occurs, and the restrained torque can be deviated. Therefore, oscillation easily occurs.

[0176] On the other hand, in a case where the retard angle control is performed, since the difference between the maximum value and the minimum value in the overall value is smaller than the difference between the maximum value and the minimum value of the overall value in the advance angle control, it is indicated that the torque is stable compared to the advance angle control. Thus, the oscillation phenomenon of the retard angle control is improved compared to the advance angle control. By improving the oscillation phenomenon, the behavior of the motor at the time of restraint of the motor is stabilized, and thus the restrained torque rises. Here, even at the time of locking of the motor, a stable torque can be output, and thus the deviation of the restrained torque is suppressed. Further, since the behavior of the motor is stable, the restrained torque can be limited within a range of a high value. In addition, since the oscillation can be suppressed, the position of the locked motor can be reduced to some extent compared to a case where the advance angle control is performed, and the deviation of the locked position can be suppressed.

[0177] The control section 54 in the embodiments can also be realized by a computer. In this case, the function can also be realized by recording a program for realizing the function in a recording medium that is readable by a computer system, and causing the computer system to read and execute the program recorded in the recording medium. Further, the "computer system" described herein includes an operating system (OS) and hardware such as peripheral devices. In addition, the "recording medium readable by a computer" refers to a portable medium such as a flexible disk, a magneto-optical disk, a read only memory (ROM), a compact disc-read only memory (CD-ROM), and a storage device such as a hard disk built in a computer system. Furthermore, the "recording medium readable by a computer" can also include a means for temporarily and dynamically holding a program for a short time, such as a communication line when a program is transmitted via a network such as the Internet or a telephone line, and a volatile memory inside a computer system that becomes a server or a client in the case, for a certain period of time. In addition, the program can be a program for realizing a part of the above-described function, a program that can realize the above-described function by being combined with a program already recorded in a computer system, or a program realized using a programmable logic device such as a field programmable gate array (FPGA).

[0178] The embodiments of the present application are described in detail above with reference to the drawings, but the specific configuration is not limited to the embodiments, and designs and the like within a range not departing from the gist of the present application are also included.

Claims

1. A motor control device that controls rotation of a rotor by energizing coils having a plurality of phases in a brushless motor, and that has: a plurality of sensors that detect a rotational position of the rotor and output a position detection signal; a rotational speed determination section that determines whether a rotational speed of the brushless motor is below a prescribed threshold value based on the position detection signal; and a motor control section that can select a first mode selected when the rotational speed of the brushless motor exceeds the threshold value and a second mode selected when the rotational speed of the brushless motor becomes below the threshold value, the motor control section having an energization control section that energizes the plurality of phases of the coils at prescribed energization timings set based on the position detection signal of each of the plurality of sensors, the energization control section energizing a first phase among the plurality of phases at the prescribed energization timing set based on the position detection signal of a first sensor among the plurality of sensors in the first mode, and energizing a second phase among the plurality of phases at the prescribed energization timing set based on the position detection signal of the first sensor in the second mode, the energization timing to the second phase being advanced relative to a timing at which the position detection signal of the first sensor becomes on in the first mode, and the energization timing to the second phase being delayed relative to the timing at which the position detection signal of the first sensor becomes on in the second mode.

2. The motor control device according to claim 1, having a load determination section that determines whether a load applied to the brushless motor is a high load, the motor control section switching from the first mode to the second mode when the brushless motor is a high load, the rotational speed of the brushless motor is below the threshold value, and the brushless motor is driven in the first mode.

3. A motor unit having: any one of a brushless wiper motor that swings a wiper arm, a brushless sunroof motor that opens and closes a sunroof panel, a brushless power window motor, a brushless power seat motor; and the motor control device according to claim 1 or 2.

4. A motor control method of a motor control device that controls rotation of a rotor by energizing coils having a plurality of phases in a brushless motor, in which: a plurality of sensors detect a rotational position of the rotor and output a position detection signal, a rotational speed of the brushless motor is determined to be below a prescribed threshold value based on the position detection signal, a first mode is selected when the rotational speed of the brushless motor exceeds the threshold value, and a second mode is selected when the rotational speed of the brushless motor becomes below the threshold value, the plurality of phases of the coils are energized at prescribed energization timings set based on the position detection signal of each of the plurality of sensors, and ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ When set to a prescribed energization timing set based on the position detection signal of a first sensor among the plurality of sensors in the first mode, the first phase among the plurality of phases is energized, in the second mode, a second phase among the plurality of phases is energized at a prescribed energization timing set based on the position detection signal of the first sensor, In the first mode, the energization timing to the second phase is made to be an advance timing of turning on with respect to the position detection signal of the first sensor, in the second mode, the energization timing to the second phase is made to be a delay timing of turning on with respect to the position detection signal of the first sensor.

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