Motor device, wiper device, and motor control method

Abstract

To suppress stall of a motor even when a load is applied at the time of starting the motor.SOLUTION: A motor device includes: a motor; a drive signal generation unit that controls a duty ratio indicating a drive output of the motor so as not to exceed a duty ratio upper limit value and generates a drive signal according to the duty ratio; an inverter that outputs an output signal for rotationally driving the motor based on the drive signal; a rotation speed detection unit that detects a rotation speed of the motor; an acceleration detection unit that detects whether or not the motor is accelerating; and an upper limit value setting unit that changes the duty ratio upper limit value to a second upper limit value higher than a first upper limit value set in advance when the rotation speed of the motor exceeds a first threshold value and the rotation of the motor is accelerating. The upper limit value setting unit sets the first upper limit value so as to gradually increase according to an increase in the rotation speed when the rotation speed is between a second threshold value lower than the first threshold value and the first threshold value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a motor device, a wiper device, and a motor control method. [Background technology]

[0002] In motor devices used in vehicle wiper devices, etc., if a load is suddenly applied while the motor is running, causing the motor's rotation speed to drop, an event may occur in which the duty (duty ratio) cannot be increased and the motor stops.To prevent such an event, a motor device has recently been known that prevents the motor from stopping by changing the upper duty limit (upper duty ratio limit) to a higher value when accelerating (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-62836 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional motor device described above, for example, when the motor rotation speed is low, in order to prevent an overcurrent from occurring due to an excessive increase in the duty cycle, the upper limit of the duty cycle is prohibited from being increased when the rotation speed is equal to or less than a predetermined threshold. As a result, in the conventional motor device, for example, when a load is applied from the time the motor is started, the duty cycle cannot be increased because the upper limit of the duty cycle is low, and there is a possibility that the motor will stall.

[0005] The present invention has been made to solve the above problems, and its purpose is to provide a motor device, a wiper device, and a motor control method that can suppress motor stall even when a load is applied when the motor is started. [Means for solving the problem]

[0006] In order to solve the above problem, one aspect of the present invention is a motor device comprising: a motor that rotates; a drive signal generation unit that controls the duty ratio indicating the drive output of the motor so that it does not exceed a duty ratio upper limit value and generates a drive signal corresponding to the duty ratio; an inverter that outputs an output signal that rotates the motor based on the drive signal; a rotation speed detection unit that detects the rotation speed of the motor; an acceleration detection unit that detects whether the motor is accelerating; and an upper limit value setting unit that executes a change process to change the duty ratio upper limit value to a second upper limit value that is higher than a predetermined first upper limit value when the rotation speed of the motor exceeds a first threshold value and the rotation of the motor is accelerating, wherein the upper limit value setting unit sets the first upper limit value so that it gradually increases as the rotation speed increases between the second threshold value that is lower than the first threshold value and the first threshold value.

[0007] Another aspect of the present invention is a motor control method for controlling a motor that is driven to rotate by an output signal output by an inverter based on a drive signal, the motor control method including: a drive signal generation step in which a drive signal generation unit controls a duty ratio indicating the drive output of the motor so that it does not exceed a duty ratio upper limit value, and generates the drive signal according to the duty ratio; a rotation speed detection step in which a rotation speed detection unit detects the rotation speed of the motor; an acceleration detection step in which an acceleration detection unit detects whether the motor is accelerating; and an upper limit value setting step in which an upper limit value setting unit executes a change process to change the duty ratio upper limit value to a second upper limit value that is higher than a predetermined first upper limit value when the rotation speed of the motor exceeds a first threshold value and the rotation of the motor is accelerating; and in the upper limit value setting step, the upper limit value setting unit sets the first upper limit value so that it gradually increases as the rotation speed increases between the second threshold value that is lower than the first threshold value and the first threshold value. [Effects of the Invention]

[0008] According to the present invention, stalling of the motor can be suppressed even when a load is applied when the motor is started. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing an example of a motor device according to a first embodiment. [Figure 2] 5 is a flowchart showing an example of a process for switching a duty limit value of the motor device according to the first embodiment. [Figure 3] 5A and 5B are diagrams illustrating an example of a process for switching a duty limit value of the motor device according to the first embodiment. [Figure 4] 4 is a flowchart showing an example of a current supply control process of the motor device according to the first embodiment. [Figure 5] 5A and 5B are diagrams illustrating an example of a current supply control process of the motor device according to the first embodiment. [Figure 6] FIG. 4 is a diagram illustrating an example of an effect of the motor device according to the first embodiment. [Figure 7] 10A and 10B are diagrams illustrating a modified example of the process for switching the duty limit value of the motor device according to the first embodiment. [Figure 8] FIG. 6 is a configuration diagram illustrating an example of a wiper device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A motor device, a wiper device, and a motor control method according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0011] [First embodiment] FIG. 1 is a block diagram showing an example of a motor device 100 according to a first embodiment. As shown in FIG. 1, the motor device 100 includes a motor 2, a rotation axis sensor 30, a control unit 40, and an inverter 50. The motor device 100 according to this embodiment is used, for example, in a wiper device that wipes the window glass of a vehicle.

[0012] The motor 2 is, for example, a three-phase, four-pole brushless motor. The motor 2 is driven to rotate by an output signal output from an inverter 50 based on a drive signal, which will be described later. The motor 2 also includes a stator 21 and a rotor 22.

[0013] The stator 21 is fixed to the inner periphery of the case of the motor 2. The stator 21 includes three-phase armature coils (21u, 21v, 21w). The armature coils (21u, 21v, 21w) are wound around the stator 21. For example, the three-phase armature coils (21u, 21v, 21w) are connected by a delta connection.

[0014] In the delta connection, the armature coil 21u and the armature coil 21w are connected by the connection point 21a, the armature coil 21v and the armature coil 21w are connected by the connection point 21b, and the armature coil 21u and the armature coil 21v are connected by the connection point 21c.

[0015] The rotor 22 is provided inside the stator 21. The rotor 22 includes, for example, a rotor shaft 22a and a four-pole permanent magnet 22b attached to the rotor shaft 22a. A plurality of bearings (not shown) are provided inside the case of the motor 2, and the rotor shaft 22a is rotatably supported by the plurality of bearings.

[0016] The rotational shaft sensor 30 detects a signal corresponding to the rotation of the rotor 22. The rotational shaft sensor 30 includes, for example, three Hall ICs (not shown). When the rotor 22 rotates, these three Hall ICs output pulse signals that are shifted in phase by 120 degrees to the control unit 40. That is, as the rotor 22 rotates, the rotational shaft sensor 30 generates pulse signals based on changes in the magnetic poles of a sensor magnet (not shown) arranged on the rotor shaft 22a, and outputs the pulse signals to the control unit 40. Each Hall IC detects a position that is shifted by 120 electrical degrees.

[0017] The control unit 40 is a processor including, for example, a CPU (Central Processing Unit) and performs overall control of the motor device 100. The control unit 40 performs PWM (Pulse Width Modulation) control, sets a duty ratio according to a target rotation output of the rotor 22 (for example, a target rotation speed TRPM), and outputs a drive signal according to the set duty ratio to the inverter 50. The control unit 40 also controls the drive of the motor 2 via the inverter 50, for example, by supplying rectangular wave current. The control unit 40 also includes a position detection unit 41, a rotation speed detection unit 42, an acceleration detection unit 43, an upper limit setting unit 44, a command generation unit 45, and a drive signal generation unit 46.

[0018] The position detection unit 41 detects the rotational position (θ) of the rotor 22 based on the pulse signal supplied from the rotational axis sensor 30. The position detection unit 41 outputs the detected rotational position of the rotor 22 to a drive signal generation unit 46, which will be described later.

[0019] The rotation speed detection unit 42 detects, for example, the rotation speed (RPM) of the motor 2 (rotor 22) based on the pulse signal supplied from the rotation axis sensor 30, and outputs the detected rotation speed of the motor 2 (rotor 22) to the acceleration detection unit 43, upper limit value setting unit 44, and command generation unit 45 described later. In this specification, the term "number of rotations" refers to the "rotational speed" which indicates the number of rotations per unit time.

[0020] The acceleration detection unit 43 detects whether the rotation of the motor 2 is accelerating. For example, the acceleration detection unit 43 detects that the motor 2 is accelerating when the rotation speed detected by the rotation speed detection unit 42 at predetermined time intervals increases a predetermined number of times in succession. The acceleration detection unit 43 outputs the detection result of whether the motor 2 is accelerating or not to the upper limit setting unit 44.

[0021] The upper limit value setting unit 44 sets a duty limit value (duty ratio upper limit value) that is the upper limit value of the duty ratio (also called output duty) that indicates the drive output of the motor 2. The duty limit value includes a normal duty limit value (first upper limit value) that is set in advance, and a corrected duty limit value (second upper limit value) that is used during acceleration of the motor 2, and the upper limit value setting unit 44 switches between and outputs the normal duty limit value (first upper limit value) and the corrected duty limit value (second upper limit value).

[0022] The normal duty limit value is a limit value used during normal operation other than during acceleration. The upper limit value setting unit 44 changes and sets the normal duty limit value according to the rotation speed of the motor 2 (hereinafter sometimes referred to as the motor rotation speed). For example, the upper limit value setting unit 44 changes the normal duty limit value to a higher value as the rotation speed increases, and changes the normal duty limit value to a lower value as the rotation speed decreases. Specifically, the upper limit value setting unit 44 changes the normal duty limit value according to the motor rotation speed, as shown in FIG. 3, which will be described later.

[0023] When the motor rotation speed exceeds rotation speed RPM1 (first threshold value) and the rotation of motor 2 is accelerating, upper limit value setting unit 44 executes a change process to change the duty limit value to a corrected duty limit value that is higher than a preset normal duty limit value.

[0024] That is, when the motor rotation speed exceeds rotation speed RPM1 and the motor 2 is accelerating, the upper limit value setting unit 44 outputs the corrected duty limit value (LMT2) as the duty limit value (LMT) to the drive signal generating unit 46. Furthermore, when the motor 2 is not accelerating (when it is decelerating or being driven at a constant speed), the upper limit value setting unit 44 outputs the normal duty limit value (LMT1) as the duty limit value (LMT) to the drive signal generating unit 46.

[0025] Furthermore, the upper limit setting unit 44 sets the normal duty limit value so that it gradually increases as the motor rotation speed increases when the motor rotation speed is between rotation speed RPM2 (second threshold value) lower than rotation speed RPM1 and rotation speed RPM1.

[0026] Furthermore, the normal duty limit value (first upper limit value) is set to a constant minimum setting value when the rotation speed is less than the rotation speed RPM2. That is, the upper limit value setting unit 44 sets the normal duty limit value to a constant minimum setting value when the rotation speed is less than the rotation speed RPM2. Furthermore, after the motor 2 starts, the upper limit value setting unit 44 gradually increases the normal duty limit value from the minimum setting value as the rotation speed increases between the rotation speed RPM2 and the rotation speed RPM1.

[0027] The upper limit setting unit 44 sets the corrected duty limit value by adding a correction amount (α) to the normal duty limit value, as shown in the following equation (1), where α is a predetermined fixed value.

[0028] Corrected duty limit value = Normal duty limit value + α (1)

[0029] When a correction amount is generated for the normal duty limit value using equation (1), if the normal duty limit value is changed according to the rotation speed of the motor 2, the correction duty limit value will also be changed according to the rotation speed of the motor 2. In other words, the upper limit value setting unit 44 changes the correction duty limit value according to the rotation speed of the motor 2.

[0030] Furthermore, in the above-mentioned formula (1), the corrected duty limit value is set by adding a fixed correction amount (α) to the normal duty limit value, but the corrected duty limit value may be set by multiplying the normal duty limit value by a predetermined constant (β), as in the following formula (2). That is, in the change process, the upper limit value setting unit 44 may change the normal duty limit value to a corrected duty limit value that is a predetermined constant multiple (β). Here, β is a predetermined fixed value equal to or greater than "1.0."

[0031] Corrected duty limit value = Normal duty limit value × β (2)

[0032] Furthermore, the upper limit value setting unit 44 disables the change process from changing the normal duty limit value to the corrected duty limit value when the rotation speed of the motor 2 is equal to or lower than the rotation speed RPM1 (first threshold value). In other words, when the rotation speed of the motor 2 is low, the upper limit value setting unit 44 performs control to output the normal duty limit value without using the corrected duty limit value even during acceleration.

[0033] The command generating unit 45 generates an output command value (command value for PWM control) according to a target rotation output (for example, target rotation speed TRPM) of the motor 2. The command generating unit 45 generates a duty ratio, which is a command value for PWM control, according to, for example, the current rotation speed (RPM) of the motor 2 acquired from the position detecting unit 41 and the target rotation speed TRPM, and outputs the generated output command value to the drive signal generating unit 46 as an output command value (DT).

[0034] The drive signal generating unit 46 generates drive signals based on the output command value (DT) output by the command generating unit 45 so that sinusoidal wave-shaped voltages are applied to the three-phase armature coils (21u, 21v, 21w) at energization timings according to the rotational position of the rotor 22. The drive signal generating unit 46 generates three-phase energization timing signals based on the rotational position (θ), for example, and generates drive signals (three-phase drive signals) that drive (turn on / off) switching elements (51a to 51f) of the inverter 50 (described later) by PWM control based on the output command value (DT), and outputs the generated drive signals (three-phase drive signals) to the inverter 50.

[0035] Furthermore, when the output command value (DT) has a duty ratio greater than the duty limit value (LMT) output from the upper limit value setting unit 44, the drive signal generating unit 46 generates a drive signal (three-phase drive signal) by PWM control using the duty limit value (LMT) instead of the output command value (DT). In this way, the drive signal generating unit 46 controls the duty ratio indicating the drive output of the motor 2 so that it does not exceed the duty limit value (LMT), and generates a drive signal according to the duty ratio.

[0036] Furthermore, drive signal generation unit 46 performs different energization control depending on the motor rotation speed. Drive signal generation unit 46 includes advance angle / energization angle control unit 47 that controls the advance angle and energization angle of the voltage applied to motor 2.

[0037] When the duty ratio is less than the duty limit value, advance conduction angle control unit 47 changes the conduction angle to a value exceeding 120 degrees and increases the advance angle. When the duty ratio is equal to the duty limit value and the rotation speed is less than RPM3 (less than the third threshold), advance conduction angle control unit 47 sets the conduction angle to 120 degrees or less. Here, rotation speed RPM3 (third threshold) is set to be greater than or equal to RPM1.

[0038] The inverter 50 outputs an output signal that rotates the motor 2 based on the drive signal generated by the drive signal generation unit 46. That is, the inverter 50 drives the switching elements (51a to 51f) based on the drive signal generated by the drive signal generation unit 46, and applies an applied voltage based on a current waveform to the three-phase armature coils (21u, 21v, 21w). The inverter 50 generates an applied voltage using DC power supplied from the battery 3 .

[0039] The inverter 50 includes six switching elements 51a to 51f connected in a three-phase bridge configuration and diodes 52a to 52f. The switching elements 51a to 51f are, for example, N-channel metal oxide semiconductor field effect transistors (MOSFETs), and form a three-phase bridge circuit.

[0040] Switching element 51a and switching element 51d are connected in series between the positive and negative terminals of battery 3 to form a U-phase bridge circuit. Switching element 51a has a drain terminal connected to the positive terminal of battery 3, a source terminal connected to node N1, and a gate terminal connected to the signal line for the upper U-phase drive signal. Switching element 51d has a drain terminal connected to node N1, a source terminal connected to the negative terminal of battery 3, and a gate terminal connected to the signal line for the lower U-phase drive signal. Node N1 is connected to connection point 21a of motor 2.

[0041] Switching element 51b and switching element 51e are connected in series between the positive and negative terminals of battery 3 to form a V-phase bridge circuit. Switching element 51b has a drain terminal connected to the positive terminal of battery 3, a source terminal connected to node N2, and a gate terminal connected to the signal line for the upper V-phase drive signal. Switching element 51e has a drain terminal connected to node N2, a source terminal connected to the negative terminal of battery 3, and a gate terminal connected to the signal line for the lower V-phase drive signal. Node N2 is connected to connection point 21b of motor 2.

[0042] Switching element 51c and switching element 51f are connected in series between the positive and negative terminals of battery 3 to form a W-phase bridge circuit. Switching element 51c has a drain terminal connected to the positive terminal of battery 3, a source terminal connected to node N3, and a gate terminal connected to the signal line for the upper W-phase drive signal. Switching element 51f has a drain terminal connected to node N3, a source terminal connected to the negative terminal of battery 3, and a gate terminal connected to the signal line for the lower W-phase drive signal. Node N3 is connected to connection point 21c of motor 2.

[0043] The diode 52a has an anode terminal connected to the node N1 and a cathode terminal connected to the positive terminal of the battery 3. The diode 52d has an anode terminal connected to the negative terminal of the battery 3 and a cathode terminal connected to the node N1.

[0044] The diode 52b has an anode terminal connected to the node N2 and a cathode terminal connected to the positive terminal of the battery 3. The diode 52e has an anode terminal connected to the negative terminal of the battery 3 and a cathode terminal connected to the node N2.

[0045] The diode 52c has an anode terminal connected to the node N3 and a cathode terminal connected to the positive terminal of the battery 3. The diode 52f has an anode terminal connected to the negative terminal of the battery 3 and a cathode terminal connected to the node N3.

[0046] The battery 3 is a DC power supply such as a lead storage battery or a lithium ion battery, and supplies power to drive the motor 2.

[0047] Next, the operation of the motor device 100 according to this embodiment will be described with reference to the drawings. 2 is a flowchart showing an example of a process for switching the duty limit value of the motor device 100 according to this embodiment. Here, the operation of the upper limit setting unit 44 of the control unit 40 will be described.

[0048] 2, the upper limit setting unit 44 first determines whether the motor rotation speed is greater than the rotation speed RPM1 (step S101). The upper limit setting unit 44 acquires the motor rotation speed RPM detected by the rotation speed detection unit 42, and determines whether the motor rotation speed RPM is greater than the rotation speed RPM1 (whether the motor rotation speed RPM is equal to or less than the rotation speed RPM1). If the motor rotation speed RPM is greater than the rotation speed RPM1 (step S101: YES), the upper limit setting unit 44 proceeds to step S102. If the motor rotation speed RPM is equal to or less than the rotation speed RPM1 (step S101: NO), the upper limit setting unit 44 proceeds to step S104.

[0049] In step S102, the upper limit setting unit 44 determines whether the motor 2 is accelerating. The upper limit setting unit 44 determines whether the motor 2 is accelerating, for example, based on the detection result output by the acceleration detection unit 43. If the motor 2 is accelerating (step S102: YES), the upper limit setting unit 44 proceeds to step S103. If the motor 2 is not accelerating (step S102: NO), the upper limit setting unit 44 proceeds to step S106.

[0050] In step S103, the upper limit setting unit 44 selects the corrected duty limit value as the duty limit value. That is, the upper limit setting unit 44 outputs the corrected duty limit value as the duty limit value (LMT) to the drive signal generating unit 46. After the processing of step S103, the upper limit setting unit 44 returns the processing to step S101.

[0051] Furthermore, in step S104, the upper limit setting unit 44 determines whether the motor rotation speed is equal to or greater than the rotation speed RPM2. The upper limit setting unit 44 acquires the motor rotation speed RPM detected by the rotation speed detection unit 42, and determines whether the motor rotation speed RPM is equal to or greater than the rotation speed RPM2. If the motor rotation speed RPM is equal to or greater than the rotation speed RPM2 (step S104: YES), the upper limit setting unit 44 proceeds to step S105. If the motor rotation speed RPM is less than the rotation speed RPM2 (step S104: NO), the upper limit setting unit 44 proceeds to step S106.

[0052] In step S105, the upper limit setting unit 44 sets the duty limit value so that it gradually increases from the set minimum value as the rotation speed increases. That is, the upper limit setting unit 44 gradually increases the normal duty limit value, which is the duty limit value (LMT), from the set minimum value as the rotation speed increases. After processing step S105, the upper limit setting unit 44 returns the processing to step S101.

[0053] Furthermore, in step S106, the upper limit setting unit 44 selects the normal duty limit value as the duty limit value. That is, the upper limit setting unit 44 outputs the normal duty limit value as the duty limit value (LMT) to the drive signal generating unit 46. After the processing of step S106, the upper limit setting unit 44 returns the processing to step S101.

[0054] Next, an example of the process of switching the duty limit value of the motor device 100 according to this embodiment will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of the process of switching the duty limit value of the motor device 100 according to this embodiment.

[0055] 3, the horizontal axis of the graph represents the rotation speed [rpm] of the motor 2, and the vertical axis represents the duty limit value [%]. Furthermore, waveform W1 represents the waveform of the normal duty limit value, and waveform W2 represents the waveform of the corrected duty limit value.

[0056] 3, rotation speed RPM0 indicates the rotation speed at which the behavior of motor 2 begins to stabilize. Furthermore, rotation speed RPM1 indicates the first threshold value described above, rotation speed RPM2 indicates the second threshold value, and rotation speed RPM3 (third threshold value) indicates the rotation speed at which the behavior of motor 2 stabilizes and wide-angle energization driving becomes possible. The minimum setting value DLmin indicates the minimum value in the setting of the duty limit value, and the maximum setting value DLmax indicates the maximum value in the setting of the duty limit value.

[0057] During a period TR1 in FIG. 3 in which the rotation speed is less than the rotation speed RPM2, the upper limit setting unit 44 sets the normal duty limit value to a fixed minimum setting value DLmin as the duty limit value, as shown by the waveform W1.

[0058] Furthermore, during a period TR2 when the rotation speed is between RPM2 and RPM1, the upper limit setting unit 44 sets the duty limit value to a normal duty limit value that gradually increases from the set minimum value DLmin as the rotation speed increases, as shown in waveform W1. After the motor 2 starts, in the setting change process from the rotation speed RPM2 to the rotation speed RPM1 (period TR2), the normal duty limit value is increased from the set minimum value DLmin in proportion to the increase in the rotation speed (directly proportional to the rotation speed).

[0059] As a result, the motor device 100 increases the normal duty limit value in proportion to the increase in rotation speed, starting from a constant set minimum value DLmin, and therefore, using a simple method, can appropriately control the duty limit value so that it does not exceed the duty limit value when a load is applied from the time the motor is started.

[0060] Furthermore, during the period TR3 in which the rotation speed exceeds the rotation speed RPM1, when the motor 2 is not accelerating, the upper limit value setting unit 44 sets the normal duty limit value as the duty limit value so that it further increases in accordance with the increase in the rotation speed, as shown in the waveform W1.

[0061] Furthermore, during a period TR3 in which the rotation speed exceeds the rotation speed RPM1, if the motor 2 is accelerating, the upper limit setting unit 44 sets the corrected duty limit value as the duty limit value, as shown by the waveform W2.

[0062] 3, period TR4 indicates a period (or a range of rotational speeds) when the rotational speed is less than RPM0, and period TR5 indicates a period (or a range of rotational speeds) when the rotational speed is between RPM0 and RPM3. Furthermore, period TR6 indicates a period (or a range of rotational speeds) when the rotational speed exceeds RPM3. The periods TR4 to TR6 will be described later in the description of the advance angle energization control.

[0063] Next, the power supply control process of the motor device 100 according to this embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing an example of the power supply control process of the motor device 100 according to this embodiment.

[0064] 4, when motor 2 is started to be driven, advance conduction angle control unit 47 of motor device 100 first executes processing for low-speed conduction control (no advance angle control, conduction angle 120 degrees) (step S201). In this case, because the behavior of motor 2 is unstable immediately after the start of motor 2 drive, advance conduction angle control unit 47 prohibits advance angle conduction.

[0065] Next, the advance angle energization angle control unit 47 determines whether or not the motor rotation speed is equal to or higher than the rotation speed RPM0 (step S202). The advance angle energization angle control unit 47 acquires the motor rotation speed (RPM) from the rotation speed detection unit 42, and determines whether or not the acquired rotation speed (RPM) is equal to or higher than the rotation speed RPM0. Here, as shown in FIG. 3 described above, the rotation speed RPM0 is a value smaller than the rotation speed RPM2 (RPM0 < RPM2). When the motor rotation speed is equal to or higher than the rotation speed RPM0 (step S202: YES), the advance angle energization angle control unit 47 advances the process to step S203. Also, when the motor rotation speed is less than the rotation speed RPM0 (step S202: NO), the advance angle energization angle control unit 47 returns the process to step S201.

[0066] In step S203, the advance angle energization angle control unit 47 executes high-speed energization control (with advance angle control, energization angle 121 degrees or more). The advance angle energization angle control unit 47 performs control, for example, with advance angle control and fixing the energization angle to a predetermined energization angle of 121 degrees or more.

[0067] Next, the advance angle energization angle control unit 47 determines whether or not the duty (output duty) is equal to or higher than the duty limit value (step S204). The advance angle energization angle control unit 47 acquires the output duty (output command value) generated by the command generation unit 45 and the duty limit value set by the upper limit value setting unit 44, and determines whether or not the output duty is equal to or higher than the duty limit value. When the output duty is equal to or higher than the duty limit value (step S204: YES), the advance angle energization angle control unit 47 advances the process to step S205. Also, when the output duty is less than the duty limit value (step S204: NO), the advance angle energization angle control unit 47 returns the process to step S202.

[0068] In step S205, advance conduction angle control unit 47 determines whether the motor rotation speed is lower than rotation speed RPM3. If the motor rotation speed is lower than rotation speed RPM3 (step S205: YES), advance conduction angle control unit 47 proceeds to step S206. If the motor rotation speed is equal to or higher than rotation speed RPM3 (step S205: NO), advance conduction angle control unit 47 proceeds to step S207.

[0069] In step S206, advance conduction angle control unit 47 performs wide angle prohibition control (with advance angle control, conduction angle 120 degrees or less). In this case, advance conduction angle control unit 47 performs control with advance angle control and fixes the conduction angle to a predetermined conduction angle (e.g., 120 degrees) that is 120 degrees or less, for example. After processing step S206, advance conduction angle control unit 47 maintains the setting of advance conduction angle control and ends the processing.

[0070] In step S207, advance conduction angle control unit 47 performs boost control (with advance control, variable control according to the target speed at conduction angles of 121 degrees or more). The target speed here is target rotation speed TRPM. After processing step S207, advance conduction angle control unit 47 maintains the setting of the boost control and ends the processing.

[0071] Next, the power supply control process of the motor device 100 according to this embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating an example of the power supply control process of the motor device 100 according to this embodiment.

[0072] As shown in FIG. 5, during period TR4 (a period when the rotation speed is less than RPM0 in FIG. 3), advance conduction angle control unit 47 performs low-speed conduction control regardless of whether the output duty is less than the duty limit value.

[0073] During period TR5 (the period from RPM0 to RPM3 in FIG. 3), if the output duty is less than the duty limit value, advance conduction angle control unit 47 performs high-speed conduction control and wide-angle conduction. Also, during period TR5, if the output duty is equal to or greater than the duty limit value, advance conduction angle control unit 47 performs wide-angle prohibition control and prohibits wide-angle conduction.

[0074] During period TR6 (the period when the rotation speed exceeds 3 RPM in FIG. 3), advance conduction angle control unit 47 performs high-speed conduction control when the output duty is less than the duty limit value, and performs boost control when the output duty is equal to or greater than the duty limit value. Thus, during period TR6 when the rotation speed exceeds 3 RPM, advance conduction angle control unit 47 always performs wide-angle conduction control.

[0075] As described above, the motor device 100 according to this embodiment includes the motor 2 that is driven to rotate, a drive signal generator 46, a rotation speed detector 42, an inverter 50, a rotation speed detector 42, an acceleration detector 43, and an upper limit value setter 44. The drive signal generator 46 controls the duty ratio, which indicates the drive output of the motor 2, so that it does not exceed a duty limit value (upper limit value of the duty ratio), and generates a drive signal corresponding to the duty ratio. The rotation speed detector 42 detects the rotation speed of the motor 2. The acceleration detector 43 detects whether the motor 2 is accelerating. The inverter 50 outputs an output signal that drives the motor 2 to rotate based on the drive signal. When the rotation speed of the motor 2 exceeds a first threshold value (rotation speed RPM1) and the rotation of the motor 2 is accelerating, the upper limit value setter 44 executes a change process to change the upper limit value of the duty ratio to a second upper limit value (corrected duty limit value) that is higher than a predetermined first upper limit value (normal duty limit value). Then, the upper limit value setting unit 44 sets the first upper limit value (normal duty limit value) to gradually increase as the rotation speed increases during the period TR2 during which the rotation speed is between a second threshold value (rotation speed RPM2) that is lower than the first threshold value (rotation speed RPM1) and the first threshold value (rotation speed RPM1).

[0076] As a result, the motor device 100 according to this embodiment sets the first upper limit value to gradually increase as the rotation speed increases between the second threshold value (rotation speed RPM2) and the first threshold value (rotation speed RPM1), so that stalling of the motor 2 can be suppressed even when a load is applied from the time the motor is started. Furthermore, by gradually increasing the first upper limit value, the motor device 100 according to this embodiment prevents an overcurrent from flowing through the motor 2 due to an excessive increase in the duty ratio. Therefore, the motor device 100 according to this embodiment can simultaneously suppress stalling and protect the motor 2 even when the motor is started.

[0077] Here, with reference to FIG. 6, the effects of motor device 100 according to this embodiment will be described by comparing the operations of a conventional motor device and motor device 100 according to this embodiment. FIG. 6 is a diagram illustrating an example of the effect of the motor device 100 according to this embodiment.

[0078] FIG. 6(a) is a diagram showing an example of the operation of a conventional motor device for comparison. In Fig. 6(a), the vertical axis of the graph represents the duty ratio [%] or the rotation angle [deg], and the horizontal axis represents time [sec]. The example shown in Fig. 6(a) shows an example in which a conventional motor device is used in a vehicle wiper.

[0079] 6(a), waveform W3 shows the time change in the duty limit value of the conventional motor device, waveform W4 shows the time change in the duty ratio (output duty) of the conventional motor device, and waveform W5 shows the time change in the rotation angle of the conventional motor device.

[0080] FIG. 6(b) is a diagram showing an example of the operation of the motor device 100 according to this embodiment. In Fig. 6(b), the vertical axis of the graph represents the duty ratio [%] or the rotation angle [deg], and the horizontal axis represents time [sec]. The example shown in Fig. 6(b) shows an example in which the motor device 100 according to this embodiment is used in a wiper of a vehicle.

[0081] 6(b), waveform W6 indicates the change over time in the duty limit value of motor device 100, and waveform W7 indicates the change over time in the duty ratio (output duty) of motor device 100. Furthermore, waveform W8 indicates the change over time in the rotation angle of motor device 100.

[0082] In a conventional motor device, when a high load occurs, the duty ratio (waveform W4) reaches the duty limit value (waveform W3), as shown in partial area P1 of Figure 6(a), causing the motor rotation speed to decrease (stall), and it takes time (period TR7) for the wiper to wipe (waveform W5).

[0083] In contrast, in the motor device 100 according to this embodiment, as shown in partial region P2 and partial region P3 in Fig. 6(b), the duty limit value is gradually increased between the second threshold (rotation speed RPM2) and the first threshold (rotation speed RPM1), so that the duty ratio (waveform W6) can be prevented from reaching the duty limit value (waveform W6). Therefore, in the motor device 100 according to this embodiment, even when a high load occurs, it does not take long for the wiper to wipe, as shown in period TR8 in Fig. 6(b). In this way, the motor device 100 according to this embodiment can prevent the motor 2 from stalling even when a load is applied from the time the motor is started.

[0084] In this embodiment, the first upper limit is set to a constant set minimum value (DLmin) when the rotation speed is less than the second threshold value (less than the rotation speed RPM2). After the motor 2 starts, the upper limit setting unit 44 gradually increases the first upper limit from the set minimum value (DLmin) as the rotation speed increases between the second threshold value (rotation speed RPM2) and the first threshold value (rotation speed RPM1).

[0085] As a result, the motor device 100 according to this embodiment gradually increases the first upper limit value as the rotation speed increases, starting from a fixed set minimum value (DLmin). Therefore, when the rotation speed is less than the second threshold value (less than rotation speed RPM2) and the behavior of motor 2 is unstable, the duty ratio is set to the minimum necessary to prevent overcurrent and prioritize protection of motor 2.

[0086] In this embodiment, the drive signal generator 46 also has an advance conduction angle control unit 47 that controls the advance angle and conduction angle of the voltage applied to the motor 2. When the duty ratio is less than the duty limit value, the advance conduction angle control unit 47 changes the conduction angle to a value greater than 120 degrees and increases the advance angle. When the duty ratio is equal to the duty limit value and the rotation speed is less than a third threshold value (less than RPM3) that is set to a first threshold value or greater (more than RPM1), the advance conduction angle control unit 47 sets the conduction angle to 120 degrees or less.

[0087] As a result, the motor device 100 of this embodiment changes the conduction angle to a value exceeding 120 degrees when the duty ratio is less than the duty limit value or when the rotation speed is equal to or greater than the third threshold value (equal to or greater than rotation speed RPM3), and performs wide-angle conduction control with an increased advance angle, thereby enabling the motor 2 to be driven at high speed while suppressing stalling of the motor 2.

[0088] Furthermore, the motor device 100 according to this embodiment controls the conduction angle to 120 degrees or less when the duty ratio is equal to the duty limit value and the rotation speed is less than the third threshold value (less than rotation speed RPM3), so that if the rotation speed does not increase despite the high duty ratio, the conduction angle can be narrowed and protection of the motor 2 can be prioritized.

[0089] Furthermore, when the duty ratio is equal to the duty limit value, the rotation speed threshold for determining whether or not to perform wide-angle energization control is set to a third threshold (rotation speed RPM3) that is equal to or greater than the first threshold (rotation speed RPM1). As a result, when the duty ratio is equal to the duty limit value, motor device 100 according to this embodiment can clearly separate the rotation speed range in which control is performed to gradually increase the first upper limit value (normal duty limit value) as the rotation speed increases, from the rotation speed range in which wide-angle energization control is performed. In other words, motor device 100 according to this embodiment can achieve both protection of motor 2 and high-speed driving.

[0090] In the present embodiment, the upper limit setting unit 44 changes the first upper limit (normal duty limit) to a second upper limit obtained by multiplying the first upper limit by a predetermined constant in the change process. As a result, the motor device 100 according to this embodiment can avoid output limitations due to the upper limit of the duty ratio even when a sudden load is applied, by using the simple method of multiplying by a predetermined constant, and can increase the motor rotation speed again.

[0091] Furthermore, by multiplying the duty limit value by a predetermined constant, the amount of change in the duty limit value increases when the first upper limit value (normal duty limit value) is large, and decreases when the first upper limit value is small. Therefore, the motor device 100 according to this embodiment can output a larger duty ratio when the restrictions imposed by the duty limit value are relaxed to proactively prevent stalling of the motor 2 and drive it at high speed. Conversely, when the motor device 100 is somewhat passive in preventing stalling of the motor 2 and drive it at high speed, and the duty limit value is somewhat restrictive, the duty ratio does not increase significantly even when the change process is performed.

[0092] Furthermore, the motor control method according to this embodiment is a motor control method for controlling the motor 2, which is driven to rotate by an output signal output from the inverter 50, based on a drive signal, and includes a drive signal generating step, a rotation speed detecting step, an acceleration detecting step, and an upper limit value setting step. In the drive signal generating step, the drive signal generating unit 46 controls the duty ratio, which indicates the drive output of the motor 2, so that it does not exceed the duty limit value, and generates a drive signal according to the duty ratio. In the rotation speed detecting step, the rotation speed detecting unit 42 detects the rotation speed of the motor 2. In the acceleration detecting step, the acceleration detecting unit 43 detects whether the motor 2 is accelerating. In the upper limit value setting step, if the rotation speed of the motor 2 exceeds the rotation speed RPM1 and the rotation of the motor 2 is accelerating, the upper limit value setting unit 44 executes a change process to change the duty limit to a second upper limit value (corrected duty limit value) that is higher than a predetermined first upper limit value (normal duty limit value). In addition, in the upper limit value setting step, the upper limit value setting unit 44 sets the first upper limit value (normal duty limit value) so that it gradually increases as the rotation speed increases between rotation speeds RPM2, which is lower than rotation speed RPM1, and RPM1.

[0093] As a result, the control method according to this embodiment has the same effect as the motor device 100 described above, and can suppress stalling of the motor 2 even when a load is applied from the time the motor is started.

[0094] In the motor device 100 according to this embodiment, as shown in FIG. 7, during the period TR3 in which the rotation speed exceeds the first threshold value (rotation speed RPM1), the upper limit value setting unit 44 may increase the first upper limit value (normal duty limit value) and the second upper limit value (corrected duty limit value) in a stepwise manner in accordance with an increase in the rotation speed.

[0095] FIG. 7 is a diagram illustrating a modified example of the process of switching the duty limit value of the motor device 100 according to the first embodiment. 7, the horizontal axis of the graph represents the rotation speed [rpm] of the motor 2, and the vertical axis represents the duty limit value [%]. Furthermore, waveform W1a represents the waveform of the normal duty limit value, and waveform W2a represents the waveform of the corrected duty limit value.

[0096] In the modification shown in FIG. 7, the upper limit setting unit 44 increases the normal duty limit value and the corrected duty limit value in a stepwise manner during the period TR3, as shown by the waveforms W1a and W2a.

[0097] Next, a wiper device 200 according to a second embodiment of the present invention will be described with reference to the drawings.

[0098] [Second embodiment] Here, an example in which the above-described motor device 100 is applied to a wiper device 200 will be described with reference to FIG. FIG. 8 is a diagram showing an example of the configuration of a wiper device 200 according to this embodiment.

[0099] 8, the wiper device 200 performs a wiping operation on the windshield surface of a window glass 10 of a vehicle 1. The wiper device 200 includes a motor device 100, a link mechanism 11, two wiper arms 12, and wiper blades 13 attached to the tip of each wiper arm 12.

[0100] 8 is the motor device 100 of the present embodiment described above, and a detailed description thereof will be omitted here. The motor device 100 includes a motor 2 and a motor control device 150.

[0101] The wiper arm 12 is driven to rotate by the motor device 100, and moves along the windshield surface of the window glass 10, performing a wiping operation with the wiper blade 13 attached to the tip thereof. The two wiper arms 12 are connected by a link mechanism 11.

[0102] The wiper blade 13 is provided so as to be pressed against the window glass 10 by the wiper arm 12. The wiper blade 13 includes a blade rubber (not shown) held by a blade holder attached to the tip of the wiper arm 12. When the wiper arm 12 is swung by the motor device 100, the wiper blade 13 reciprocates within a wiping range on the outer surface of the window glass 10, wiping the window glass 10 with the blade rubber (not shown).

[0103] As described above, the wiper device 200 according to this embodiment includes the motor device 100 described above, and uses the motor device 100 to cause the wiper members (the wiper arm 12 and the wiper blade 13) to perform a wiping operation on the windshield surface.

[0104] As a result, the wiper device 200 according to this embodiment has the same effect as the motor device 100 described above, and can suppress stalling of the motor 2 even when a load is applied from the time the motor is started.

[0105] The present invention is not limited to the above-described embodiments, and can be modified within the scope of the present invention. For example, in the above embodiment, an example was described in which the three-phase armature coils (21u, 21v, 21w) of the motor 2 are connected by a delta connection, but this is not limited to this and other connections such as a star connection may also be used.

[0106] Furthermore, in each of the above embodiments, the upper limit value setting unit 44 generates and sets the corrected duty limit value from the normal duty limit value using the above-mentioned formula (1) or formula (2), but this is not limited to this, and the correction amount may be changed according to the rotation speed, as shown in the following formula (3).

[0107] Corrected duty limit value = Normal duty limit value + α × RPM (3)

[0108] In addition, in each of the above embodiments, an example has been described in which the upper limit value setting unit 44 increases the normal duty limit value in direct proportion to the rotation speed in the setting change process between the rotation speed RPM2 and the rotation speed RPM1, but this is not limited to this, and the duty limit value may be increased in a stepwise manner or a quadratic curve manner as the rotation speed increases.

[0109] Furthermore, in the above embodiment, an example has been described in which the motor device 100 is used in the wiper device 200, but the present invention is not limited to this, and the motor device 100 may be used for other purposes.

[0110] Each of the components of the motor device 100 described above has an internal computer system. A program for realizing the functions of each of the components of the motor device 100 described above may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed to perform processing in each of the components of the motor device 100 described above. Here, "reading a program recorded on a recording medium into a computer system and executing it" includes installing the program into a computer system. The "computer system" referred to here includes hardware such as an OS and peripheral devices. Furthermore, a "computer system" may include multiple computer devices connected via a network, including communication lines such as the Internet, WAN, LAN, and dedicated lines. Furthermore, a "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into a computer system. Thus, the recording medium storing the program may be a non-transitory recording medium such as a CD-ROM.

[0111] Furthermore, some or all of the above-described functions may be realized as an integrated circuit such as an LSI (Large Scale Integration). Each of the above-described functions may be individually implemented as a processor, or some or all of the functions may be integrated into a processor. Furthermore, the integrated circuit implementation method is not limited to LSI, and may be implemented using a dedicated circuit or a general-purpose processor. Furthermore, if an integrated circuit implementation technology that can replace LSI emerges due to advances in semiconductor technology, an integrated circuit based on that technology may be used. [Explanation of symbols]

[0112] 1...vehicle, 2...motor, 3...battery, 10...window glass, 11...link mechanism, 12...wiper arm, 13...wiper blade, 21...stator, 21u, 21v, 21w...armature coil, 22...rotor, 22a...rotor shaft, 22b...permanent magnet, 30...rotation shaft sensor, 40...control unit, 41...position detection unit, 42...rotation speed detection unit, 43...acceleration detection unit, 44...upper limit value setting unit, 45...command generation unit, 46...drive signal generation unit, 47...advance conduction angle control unit, 50...inverter, 51, 51a to 51f...switching elements, 52, 52a to 52f...diodes, 100...motor device, 200...wiper device

Claims

1. a motor that drives the rotation; a drive signal generating unit that controls a duty ratio indicating a drive output of the motor so that the duty ratio does not exceed an upper duty ratio limit value, and generates a drive signal according to the duty ratio; an inverter that outputs an output signal for driving the motor to rotate based on the drive signal; a rotation speed detection unit that detects the rotation speed of the motor; an acceleration detection unit that detects whether the motor is accelerating; an upper limit value setting unit that executes a change process to change the duty ratio upper limit value to a second upper limit value that is higher than a preset first upper limit value when the rotation speed of the motor exceeds a first threshold value and the rotation of the motor is accelerating; Equipped with The upper limit setting unit sets the first upper limit so as to gradually increase as the rotation speed increases, while the rotation speed is between a second threshold value lower than the first threshold value and the first threshold value. Motor device.

2. the first upper limit value is set to a set minimum value that is a constant value when the rotation speed is less than the second threshold value, The upper limit value setting unit gradually increases the first upper limit value from the set minimum value as the rotation speed increases between the second threshold value and the first threshold value after the motor starts. The motor device according to claim 1 .

3. the drive signal generation unit has an advance angle / conduction angle control unit that controls an advance angle and a conduction angle of a voltage applied to the motor, The advance conduction angle control unit is When the duty ratio is less than the duty ratio upper limit value, the conduction angle is changed to a value exceeding 120 degrees and the advance angle is increased, When the duty ratio is equal to the upper duty ratio limit value and the rotation speed is less than a third threshold value that is set to be equal to or greater than the first threshold value, the conduction angle is set to 120 degrees or less. The motor device according to claim 1 .

4. In the change process, the upper limit setting unit changes the first upper limit to the second upper limit obtained by multiplying the first upper limit by a predetermined constant. The motor device according to claim 1 .

5. A motor device according to any one of claims 1 to 4, The motor device is used to cause the wiper member to perform a wiping operation on the windshield surface. Wiper device.

6. A motor control method for controlling a motor that is driven to rotate by an output signal output from an inverter based on a drive signal, comprising: a drive signal generating step in which a drive signal generating unit controls a duty ratio indicating a drive output of the motor so as not to exceed an upper duty ratio upper limit value, and generates the drive signal according to the duty ratio; a rotation speed detection step in which a rotation speed detection unit detects the rotation speed of the motor; an acceleration detection step in which an acceleration detection unit detects whether the motor is accelerating; an upper limit value setting step in which an upper limit value setting unit executes a change process to change the duty ratio upper limit value to a second upper limit value that is higher than a preset first upper limit value when the rotation speed of the motor exceeds a first threshold value and the rotation of the motor is accelerating; Including, In the upper limit value setting step, the upper limit value setting unit sets the first upper limit value so as to gradually increase as the rotation speed increases between a second threshold value lower than the first threshold value and the first threshold value. Motor control methods.

Images