Motor control device, motor device, wiper device, and motor control method

Abstract

To properly drive a motor even when a high load is present from the beginning of motor drive.SOLUTION: A motor control device controls a motor with an output shaft. The motor control device includes: a vehicle speed detection unit for detecting a vehicle speed which is a traveling speed of a vehicle in which the motor is mounted; and a drive control unit for controlling switching between a first drive mode in which the motor is driven and a second drive mode in which the rotation speed of the output shaft and the output of the motor are higher than those in the first drive mode on the basis of the vehicle speed detected by the vehicle speed detection unit.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In recent years, in motor control, a motor control device that switches between different drive modes according to the load magnitude, for example, a fluxless drive mode and a rectangular wave drive mode, is known (see, for example, Patent Document 1). Here, the fluxless drive mode is a drive mode that outputs 1 / 2 of the Duty to the OFF phase (corresponding to the phase open period; hereinafter sometimes referred to as the free phase) among the three phases, and when driven with the same power, it is a low-output drive mode in which the rotational speed is lower than that of the rectangular wave drive mode. In Patent Document 1, switching control of the drive mode is performed based on a value determined according to the load, specifically, based on a load integrated value obtained by integrating the load.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in motor driving mounted on a vehicle such as a wiper device, for example, a high load may occur from the initial stage of driving, such as when the vehicle is running. However, in the motor control device as described above, when a high load occurs from the initial stage of driving, since the load has not been integrated yet, for example, it may be switched to a low-output drive mode such as the fluxless drive mode, and there is a possibility that the motor drive may stop halfway.

[0005] The present invention has been made to solve the above problems, and its objective is to provide a motor control device, motor device, wiper device, and motor control method that can properly drive a motor even when a high load is generated from the initial stage of motor drive. [Means for solving the problem]

[0006] To solve the above problems, one aspect of the present invention is: Not used as the power source for moving the vehicle. Output axis and 3-phase winding and has Brushless A motor control device for controlling a motor, the Brushless A motor will be installed. The aforementioned A vehicle speed detection unit detects the vehicle speed, which is the speed at which the vehicle is traveling, and based on the vehicle speed detected by the vehicle speed detection unit, Brushless A first drive mode for driving the motor, the rotational speed of the output shaft and the Brushless The system includes a drive control unit that performs control to switch between a second drive mode in which the motor output is higher than the first drive mode. The drive control unit controls the conduction of a plurality of switching elements in an inverter that generates a three-phase drive signal by switching between the first drive mode and the second drive mode. When the vehicle speed exceeds a predetermined first threshold, the unit switches from the first drive mode to the second drive mode. When the vehicle speed falls below a second threshold lower than the first threshold, the unit switches from the second drive mode to the first drive mode. The second drive mode is a square wave drive mode, and the first drive mode controls the open-circuit period of the phase that is not energized in the square wave drive mode among the three-phase drive signal lines that drive the brushless motor, using PWM (Pulse Width Modulation). This is a free-response drive mode in which a drive signal with an intermediate duty cycle is output by Modulation control, a drive signal with the maximum duty cycle is output to one of the other two phase drive signal lines, and a drive signal with the minimum duty cycle is output to the other of the other two phase drive signal lines, the intermediate duty cycle is set to a value between the maximum duty cycle and the minimum duty cycle, the drive control unit switches from the free-response drive mode to the square wave drive mode when the vehicle speed becomes equal to or greater than the first threshold, and switches from the square wave drive mode to the free-response drive mode when the vehicle speed becomes equal to or less than the second threshold. This is a motor control device.

[0007] Furthermore, one embodiment of the present invention is: Not used as the power source for moving the vehicle. Output axis and 3-phase winding and has Brushless A motor control method for controlling a motor, wherein the vehicle speed detection unit is Brushless A motor will be installed. The aforementioned A vehicle speed detection step detects the vehicle speed, which is the vehicle's travel speed, and a drive control unit, based on the vehicle speed detected by the vehicle speed detection step, Brushless A first drive mode for driving the motor, the rotational speed of the output shaft and the Brushless The control includes a drive control step that performs control to switch between a second drive mode in which the motor output is higher than the first drive mode. Furthermore, in the drive control step, the drive control unit controls the conduction of a plurality of switching elements in an inverter that generates a three-phase drive signal by switching between the first drive mode and the second drive mode, and switches from the first drive mode to the second drive mode when the vehicle speed becomes equal to or greater than a predetermined first threshold, and switches from the second drive mode to the first drive mode when the vehicle speed becomes equal to or less than a second threshold lower than the first threshold, and the second drive mode is a square wave drive mode, and the first drive mode is a PWM (Pulse Width Modulation) applied to the open-circuit period of the phase that is not energized in the square wave drive mode among the three-phase drive signal lines that drive the brushless motor. This is a free-response drive mode in which a drive signal with an intermediate duty cycle is output by Modulation control, a drive signal with the maximum duty cycle is output to one of the other two phase drive signal lines, and a drive signal with the minimum duty cycle is output to the other of the other two phase drive signal lines, the intermediate duty cycle is set to a value between the maximum duty cycle and the minimum duty cycle, and in the drive control step, the drive control unit switches from the free-response drive mode to the square wave drive mode when the vehicle speed becomes equal to or greater than the first threshold, and switches from the square wave drive mode to the free-response drive mode when the vehicle speed becomes equal to or less than the second threshold. This is a motor control method. [Effects of the Invention]

[0008] According to the present invention, even when a high load is generated from the initial stage of motor operation, the motor can be driven appropriately.

Brief Description of the Drawings

[0009] [Figure 1] It is a block diagram showing an example of a motor device according to this embodiment. [Figure 2] It is a diagram showing an example of a rectangular wave drive pattern in this embodiment. [Figure 3] It is a diagram summarizing an example of a rectangular wave drive pattern in this embodiment in a table. [Figure 4] It is a diagram showing a first example of a sensorless drive pattern in this embodiment. [Figure 5] It is a diagram summarizing a first example of a sensorless drive pattern in this embodiment in a table. [Figure 6] It is a diagram showing a second example of a sensorless drive pattern in this embodiment. [Figure 7] It is a diagram summarizing a second example of a sensorless drive pattern in this embodiment in a table. [Figure 8] It is a diagram showing an example of the switching operation of the drive mode of a motor control device according to this embodiment. [Figure 9] It is a flowchart showing an example of the switching operation of the drive mode of a motor control device according to this embodiment. [Figure 10] It is a flowchart showing another example of the switching operation of the drive mode of a motor control device according to this embodiment. [Figure 11] It is a flowchart showing a modified example of the switching operation of the drive mode of a motor control device according to this embodiment. [Figure 12] It is a configuration diagram showing an example of a wiper device according to this embodiment.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, a motor control device, a motor device, a wiper device, and a motor control method according to an embodiment of the present invention will be described with reference to the drawings.

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

[0012] In the present embodiment, the control unit 40 and the inverter 50 correspond to a motor control device 150. Further, a battery 3 and an ECU 4 (Engine Control Unit) are connected to the motor control device 150.

[0013] The motor 2 is, for example, a three-phase four-pole brushless motor. The motor 2 is rotationally driven by an output signal (applied voltage) output from the inverter 50 based on a drive signal described later. The motor 2 includes a stator 21 and a rotor 22.

[0014] The stator 21 is fixed to the inner circumference of the case of the motor 2. The stator 21 includes three-phase windings (21u, 21v, 21w). The stator 21 has the windings (21u, 21v, 21w) wound thereon. For example, the three-phase windings (21u, 21v, 21w) are connected by a delta connection.

[0015] In the delta connection, the winding 21u and the winding 21w are connected by a connection point 21a, the winding 21v and the winding 21w are connected by a connection point 21c, and the winding 21u and the winding 21v are connected by a connection point 21b.

[0016] The rotor 22 is provided inside the stator 21. The rotor 22 includes, for example, a rotor shaft 22a and four-pole permanent magnets 22b attached to the rotor shaft 22a. A plurality of bearings (not shown) are provided in the case of the motor 2, and the rotor shaft 22a is rotatably supported by the plurality of bearings.

[0017] The position detection unit 30 detects a signal corresponding to the rotation of the rotor 22. The position detection unit 30 includes, for example, three Hall elements (30u, 30v, 30w). When the rotor 22 rotates, these three Hall elements (30u, 30v, 30w) each output pulse signals to the control unit 40 that are 120 degrees out of phase with each other. That is, the position detection unit 30 generates pulse signals based on the change in the magnetic pole of a sensor magnet (not shown) placed on the rotor shaft 22a as the rotor 22 rotates, and outputs them to the control unit 40. Each Hall element (30u, 30v, 30w) detects a position shifted by 120 degrees in electrical angle.

[0018] In this embodiment, Hall element 30u outputs a digital signal (position detection signal Hu) corresponding to the U phase, and Hall element 30v outputs a digital signal (position detection signal Hv) corresponding to the V phase. In addition, Hall element 30w outputs a digital signal (position detection signal Hw) corresponding to the W phase. The three Hall elements (30u, 30v, 30w) in this embodiment are positioned relative to the rotor 22 such that when the output of the inverter 50 is immediately changed at each position where the level of the output signals of the three Hall elements (30u, 30v, 30w) changes, i.e., at each position where an edge occurs in the output signal, the electrical angle advance is 30 degrees.

[0019] The inverter 50 is controlled, for example, by PWM (Pulse Width Modulation) based on the drive signal generated by the drive control unit 43 (described later), and applies voltage to the three phase windings (21u, 21v, 21w) of the motor 2. That is, the inverter 50 switches the switching elements (51a to 51f) (conducting / non-conducting) based on the drive signal generated by the drive control unit 43, thereby changing the magnitude of the output voltage applied to the motor 2 (duty cycle), the energizing period (energetic angle), and the energizing timing (advance angle). Here, the duty cycle represents the ratio of the conduction period of the corresponding switching element in the PWM period.

[0020] The inverter 50 generates the applied voltage using DC power supplied from the battery 3. The battery 3 is a DC power source such as a lead-acid battery or a lithium-ion battery, and supplies power to drive the motor 2.

[0021] The inverter 50 comprises six three-phase bridge-connected switching elements 51a to 51f and diodes 52a to 52f. The switching elements 51a to 51f are, for example, N-channel MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) and constitute a three-phase bridge circuit.

[0022] Switching elements 51a and 51d are connected in series between the positive and negative terminals of the battery 3, forming a U-phase bridge circuit. Switching element 51a has its drain terminal connected to the positive terminal of the battery 3, its source terminal connected to node N1, and its gate terminal connected to the signal line of the upper U-phase drive signal. Switching element 51d has its drain terminal connected to node N1, its source terminal connected to the negative terminal of the battery 3, and its gate terminal connected to the signal line of the lower U-phase drive signal. Node N1 is connected to the connection point 21a of the motor 2.

[0023] Switching elements 51b and 51e are connected in series between the positive and negative terminals of the battery 3, forming a V-phase bridge circuit. Switching element 51b has its drain terminal connected to the positive terminal of the battery 3, its source terminal connected to node N2, and its gate terminal connected to the signal line of the upper V-phase drive signal. Switching element 51e has its drain terminal connected to node N2, its source terminal connected to the negative terminal of the battery 3, and its gate terminal connected to the signal line of the lower V-phase drive signal. Node N2 is connected to the connection point 21b of the motor 2.

[0024] Switching elements 51c and 51f are connected in series between the positive and negative terminals of the battery 3, forming a W-phase bridge circuit. Switching element 51c has its drain terminal connected to the positive terminal of the battery 3, its source terminal connected to node N3, and its gate terminal connected to the signal line of the upper W-phase drive signal. Switching element 51f has its drain terminal connected to node N3, its source terminal connected to the negative terminal of the battery 3, and its gate terminal connected to the signal line of the lower W-phase drive signal. Node N3 is connected to the connection point 21c of the motor 2.

[0025] Furthermore, diode 52a has its anode terminal connected to node N1 and its cathode terminal connected to the positive terminal of battery 3. Similarly, diode 52d has its anode terminal connected to the negative terminal of battery 3 and its cathode terminal connected to node N1.

[0026] Furthermore, diode 52b has its anode terminal connected to node N2 and its cathode terminal connected to the positive terminal of battery 3. Similarly, diode 52e has its anode terminal connected to the negative terminal of battery 3 and its cathode terminal connected to node N2.

[0027] Furthermore, diode 52c has its anode terminal connected to node N3 and its cathode terminal connected to the positive terminal of battery 3. Similarly, diode 52f has its anode terminal connected to the negative terminal of battery 3 and its cathode terminal connected to node N3.

[0028] The control unit 40 is a processor, for example, a CPU (Central Processing Unit), and comprehensively controls the motor device 100. The control unit 40 generates a drive signal corresponding to the rotational output of the target rotor 22 (for example, the target rotational speed TRPM) and outputs the generated drive signal to the inverter 50. The control unit 40 transmits and receives predetermined information between the ECU 4 and the motor 2. Furthermore, the control unit 40 includes a load integration value generation unit 41, a vehicle speed detection unit 42, and a drive control unit 43.

[0029] The load integration value generation unit 41 performs high load detection processing for the rotor 22 based on the set rotational speed (rotational speed) and duty cycle of the rotor 22. The load integration value generation unit 41 calculates and accumulates load point values ​​from the motor speed (rotational speed of the rotor 22) and duty cycle, and generates an accumulated point value (load integration value). The rotational speed of the rotor 22 is detected based on the output signals of three Hall elements (30u, 30v, 30w).

[0030] The load integration value generation unit 41 obtains load point values ​​corresponding to the motor speed, duty cycle, and power supply voltage by referring to a load point map (not shown) which associates the motor speed, duty cycle, and power supply voltage with load point values. The load integration value generation unit 41 integrates the obtained load point values ​​to generate a cumulative point value as the load integration value.

[0031] The cumulative point value (load integration value) becomes a large positive value when a high load condition persists because the load point values ​​are consecutively positive. On the other hand, when a normal or light load condition persists, the load point values ​​are consecutively "0" or negative, so the value becomes "0" or less. Here, the cumulative point value is always "0" if it is "0" or less, so when motor 2 is operating normally, the cumulative point value shows "0". Also, if the motor was in a high load condition but then the load is reduced to a controllable range, the cumulative load point value is gradually subtracted and eventually converges to "0" or a small positive value. Therefore, by looking at the cumulative point value, it is possible to understand the current situation of motor 2, and if the value exceeds a certain level, it can be determined that it is under high load. In this way, the cumulative point value (load integration value) is an indicator value of the load on motor 2, and the control unit 40 uses the cumulative point value (load integration value) to control the motor drive.

[0032] The vehicle speed detection unit 42 detects the vehicle speed, which is the speed at which the vehicle on which the motor 2 is mounted is traveling. The vehicle speed detection unit 42 detects the vehicle speed based on the vehicle speed signal output from the ECU 4.

[0033] The drive control unit 43 generates a drive signal corresponding to the rotational output of the target rotor 22 (for example, the target rotational speed TRPM) and outputs the generated drive signal to the inverter 50. The drive control unit 43 controls the drive of the motor 2 by switching between, for example, a square wave drive mode (an example of a second drive mode) and a free-response drive mode (an example of a first drive mode). The square wave drive mode is a high-output drive mode in which the minimum rotational speed at which the rotor shaft 22a can be rotated by the input power is higher than that of the free-response drive mode. Here, with reference to Figures 2 to 7, the details of the square wave drive mode and the free-response drive mode will be explained.

[0034] Figures 2, 4, and 6 are explanatory diagrams illustrating the position detection signals (Hu, Hv, Hw) output by the Hall element (30u, 30v, 30w) and an example of the advance angle and energization angle in the energization control of the inverter 50. Figures 2, 4, and 6 show the correspondence between the position detection signals (Hu, Hv, Hw) and the angular range in which the switching elements 51a to 51f are turned on. The horizontal axis represents the rotational position of the magnetic poles of the rotor 22 of the motor 2 in terms of electrical angles.

[0035] The position detection signals (Hu, Hv, Hw) have a phase difference of 120 degrees from each other, with an electrical angle of 360 degrees as one period, and change to either an H state (High state) or an L state (Low state) every 180 degrees. In this embodiment, the change of the position detection signal Hu from the L state to the H state is referred to as Hall edge HE1, and the change from the H state to the L state is referred to as Hall edge HE4. Similarly, the change of the position detection signal Hv from the L state to the H state is referred to as Hall edge HE3, and the change from the H state to the L state is referred to as Hall edge HE6. Furthermore, the change of the position detection signal Hw from the L state to the H state is referred to as Hall edge HE5, and the change from the H state to the L state is referred to as Hall edge HE2.

[0036] Assuming that the position detection signals (Hu, Hv, Hw) output by the Hall element (30u, 30v, 30w) contain no errors, the electrical angle between each Hall edge is 60 degrees. Furthermore, the space between Hall edge HE1 and Hall edge HE2 is referred to as Hall Stage 1 (hereinafter simply referred to as Stage 1 (hereinafter the same)), the space between Hall edge HE2 and Hall edge HE3 is referred to as Stage 2, and the space between Hall edge HE3 and Hall edge HE4 is referred to as Stage 3. Furthermore, the space between Hall edge HE4 and Hall edge HE5 is referred to as Stage 4, the space between Hall edge HE5 and Hall edge HE6 is referred to as Stage 5, and the space between Hall edge HE6 and Hall edge HE1 is referred to as Stage 6.

[0037] Figure 2 shows an example of a rectangular wave driving pattern in this embodiment. Figure 2 shows the correspondence between the position detection signals (Hu, Hv, Hw) and the energization patterns of each switching element 51a to 51f, with the horizontal axis representing the electrical angle. One example of energization control shown in Figure 2 is when the advance angle is 20 degrees and the energization angle is 130 degrees.

[0038] The energizing pattern is a combination of the following states for each switching element 51a to 51f: continuously ON ("ON"), continuously OFF ("OFF") (a period other than "ON" or "PWM", also called a free phase period), or controlled to be ON or OFF at a constant period (PWM controlled state) ("PWM"). Each stage 1 to 6 is further divided into three sections A', B', and C'. An individual energizing pattern is set for sections A', B', and C'. The duration (electrical angle) of sections A', B', and C' changes depending on the advance angle value and the energizing angle value.

[0039] For example, in stage 1 enclosed by hole edge HE1 and hole edge HE2, the energizing pattern in section A' is a combination of "ON", "OFF", "PWM", "PWM", "OFF", and "OFF" for switching elements 51a to 51f, respectively. Similarly, the energizing pattern in section B' is a combination of "ON", "OFF", "PWM", "PWM", "ON", and "OFF" for switching elements 51a to 51f, respectively. Furthermore, the energizing pattern in section C' is a combination of "OFF", "OFF", "PWM", "PWM", "ON", and "OFF" for switching elements 51a to 51f, respectively.

[0040] Furthermore, Figure 3 is a table summarizing an example of the rectangular wave energization pattern in this embodiment shown in Figure 2. The ROM (not shown) in the control unit 40 stores the rectangular wave energization pattern in a format such as that shown in Figure 3. In Figure 3, "1" represents on, "0" represents off, and "P" represents PWM.

[0041] As mentioned above, there are three possible combinations that constitute a square wave current flow pattern: (1) to (3) below. (1) First state: Each switching element 51a to 51f is in a continuously ON state ("ON"). (2) Second state: Each switching element 51a to 51f is continuously in the OFF state (a period other than ON or PWM). (3) Third state: Each switching element 51a to 51f is in a state where it is controlled to be on or off at a constant period (PWM controlled state) ("PWM").

[0042] In this manner, the drive control unit 43 controls the conduction (energy supply) of the switching elements 51a to 51f in the square wave drive mode using the square wave energization pattern described above.

[0043] Next, the free-response drive mode will be explained with reference to Figures 4 to 7. There are two methods for controlling the free-resistance energization pattern used in free-resistance drive mode.

[0044] In the first method of free-response energization, the duty cycle of the PWM signal for a switching element connected to one of the three phases is set to an intermediate value between the duty cycles of the respective PWM signals for switching elements connected to the other two phases.

[0045] Furthermore, in the second method of free-response energization, the duty cycle of the PWM signal for the switching element connected to the coil of one of the three phases is set to half of the externally inputted instruction duty cycle, and the duty cycles of the PWM signals for the switching elements connected to the coils of the other two phases are set to the same value as the instruction duty cycle and to 100%, respectively.

[0046] <First method of free-resist power supply> In the drive and energization using the free-resist energization pattern of the first method, each of the above states (1) to (3) is changed to one of the following three states (4) to (6).

[0047] (4) Fourth state: The first state is changed to the fourth state (hereinafter referred to as the "PL" state), which is PWM controlled by a PWM signal with a maximum duty cycle larger than that of the third state. (5) Fifth state: The third state is changed to the fifth state (hereinafter referred to as the "PS" state), which is PWM controlled by a PWM signal with a minimum duty cycle smaller than that of the PWM control in the third state. (6) Sixth state: The second state is changed to the sixth state (hereinafter referred to as the "PM" state), which is PWM controlled by a PWM signal with a duty cycle intermediate between the maximum duty cycle and the minimum duty cycle.

[0048] In other words, the timing at which the U-phase, V-phase, and W-phase windings (21u, 21v, 21w) enter the PM state (6th state) in the free-resist current pattern is the same as the timing at which the U-phase, V-phase, and W-phase windings (21u, 21v, 21w) enter the OFF-phase coil (2nd state) in the square wave current pattern.

[0049] This addresses the problem where the control circuit (drive control unit 43) that drives the switching elements 51a to 51f malfunctions when a negative voltage is generated at the input terminal of the motor 2 when the energizing pattern switches from the first state to the second state. Furthermore, even during the free timing (phase open period: the period in the second state) in 120-degree square wave energizing, PWM control as in the sixth state results in 180-degree energizing, and the current waveform during commutation becomes smoother, which is expected to have the effect of making the drive noise quieter (reducing motor operating noise).

[0050] In this embodiment, the intermediate duty cycle is 50%. The maximum duty cycle is the intermediate duty cycle plus half of the externally inputted instruction duty cycle. The minimum duty cycle is the intermediate duty cycle minus half of the instruction duty cycle.

[0051] For example, if the instructed duty cycle is 80%, the intermediate duty cycle is pre-set to 50%, so the maximum duty cycle is (50 + 80 ÷ 2) = 90%, and the minimum duty cycle is (50 - 80 ÷ 2) = 10%. The instructed duty cycle is assumed to be pre-stored by the user in the ROM (not shown) of the control unit 40.

[0052] Here, the negative-side switching elements 51d to 51f receive a PWM signal that is in the opposite phase to the PWM signal input to the positive-side switching elements 51a to 51c. Therefore, the duty cycle of the PWM signal driving the paired switching elements is different for the positive and negative sides. However, in this embodiment, the duty cycle of the PWM signal driving the positive-side switching elements 51a to 51c is referred to as the duty cycle of the PWM signal driving the paired switching elements.

[0053] Figure 4 shows an example of a free-resist current flow pattern for the first method. Figure 4 shows the correspondence between the position detection signals (Hu, Hv, Hw) and the energization patterns of each switching element 51a to 51f, with the horizontal axis representing the electrical angle.

[0054] The example of energization control shown in Figure 4 is for a case where the advance angle is 20 degrees and the energization angle is 130 degrees. The energization pattern is a combination of one of the following states in which each switching element 51a to 51f is continuously turned on ("ON"), i.e., changed from "ON" (first state) to "PL" (fourth state); continuously turned off ("OFF") (period other than "ON" or "PWM"), i.e., changed from "OFF" (second state) to "PM" (sixth state); or controlled to be turned on or off at a constant period (PWM controlled state) ("PWM"), i.e., changed from "PWM" (third state) to "PS" (fifth state).

[0055] Each stage from 1 to 6 is further divided into three sections: A, B, and C. Each section has its own set of energizing pattern. The duration (electrical angle) of each section (A, B, and C) varies depending on the advance angle and the energizing angle.

[0056] In the PWM-controlled state, each switching element 51a to 51f repeatedly switches between ON and OFF, so the waveform is actually a rectangular wave with multiple peaks and valleys. However, for convenience, in Figure 4 and Figure 6 described later, the ON / OFF states of each switching element 51a to 51f are not explicitly indicated, and the term "PWM phase" is used. Here, in Figure 4, the "PL" state is denoted as "PWM phase (MAX Duty)", the "PS" state as "PWM phase (MIN Duty)", and the "PM" state as "PWM phase (Duty=50)".

[0057] For example, in stage 1 enclosed by hole edge HE1 and hole edge HE2, the energizing pattern in section A is such that the switching elements 51a to 51f are in the combinations of "PL", "PL", "PS", "PS", "PM", and "PM". Also, the energizing pattern in section B is such that the switching elements 51a to 51f are in the combinations of "PL", "PL", "PS", "PS", "PL", and "PL". Furthermore, the energizing pattern in section C is such that the switching elements 51a to 51f are in the combinations of "PM", "PM", "PS", "PS", "PL", and "PL".

[0058] Furthermore, Figure 5 is a table summarizing an example of the free-resistance energizing pattern of the first method shown in Figure 4. The ROM (not shown) in the control unit 40 stores the free-resistance energizing pattern in a format such as that shown in Figure 5. In Figure 5, "PL" represents the fourth state controlled by a PWM signal with the maximum duty cycle, "PS" represents the fifth state controlled by a PWM signal with the minimum duty cycle, and "PM" represents the sixth state controlled by a PWM signal with a duty cycle intermediate between the maximum and minimum duty cycles. In this manner, the drive control unit 43 controls the conduction (energy supply) of the switching elements 51a to 51f in the free-resist drive mode (first method) using the free-resist energizing pattern described above.

[0059] <Second method of free-resist power supply> In the second method of driving and energizing using a free-resistance energizing pattern, each of the above states (1) to (3) is changed to one of the following three states (4) to (6). Each of the following three states (7) to (9) is changed. Note that the control for each switching element is the same in state (1) and state (7), so the state does not actually change.

[0060] (7) Seventh state: Maintain the first state, and keep each switching element 51a to 51f continuously turned on ("ON"). (8) Eighth state: The third state is changed to the eighth state (hereinafter referred to as the "P1" state) which is PWM controlled by a PWM signal of an externally input instruction duty cycle. (9) Ninth state: The second state is changed to the ninth state (hereinafter referred to as the "P2" state) which is PWM controlled by a PWM signal with a duty cycle of 1 / 2 of the instructed duty cycle input from an external source.

[0061] In other words, the timing at which the U-phase, V-phase, and W-phase windings (21u, 21v, 21w) enter the P2 state (9th state) in the free-response energizing pattern is the same as the timing at which the U-phase, V-phase, and W-phase windings (21u, 21v, 21w) enter the OFF-phase winding (2nd state) in the square wave energizing pattern.

[0062] This addresses the problem where the control circuit (control unit 40) that drives the switching element malfunctions when a negative voltage is generated at the input terminal of motor 2 when the energizing pattern switches from the first state to the second state. Furthermore, even during the free timing (phase open period: the period in the second state) in 120-degree square wave energizing, PWM control as in the ninth state results in 180-degree energizing, and the current waveform during commutation becomes smoother, which is expected to have the effect of making the drive noise quieter (reducing motor operating noise). In other words, the same effect can be expected regardless of whether the first or second free-resistance energizing pattern is used for driving and energizing.

[0063] In this embodiment, the duty cycle in the seventh state is 100%. For example, if the indicated duty cycle is 80%, the duty cycle in the eighth state will be 80%, and the duty cycle in the ninth state will be 80 ÷ 2 = 40%. The instructed duty cycle is to be stored in advance by the user in the ROM (not shown) of the control unit 40.

[0064] Figure 6 shows an example of a free-resist current flow pattern for the second method. Figure 6 shows the correspondence between the position detection signals (Hu, Hv, Hw) and the energization patterns of each switching element 51a to 51f, with the horizontal axis representing the electrical angle.

[0065] The example of energization control shown in Figure 6 is for a case where the advance angle is 20 degrees and the energization angle is 130 degrees. The energization pattern is a combination of one of the following states in which each switching element 51a to 51f is continuously turned on ("ON"), i.e., maintains the "ON" (first state) state (seventh state); is continuously turned off ("OFF") (period other than "ON" or "PWM"), i.e., changes from "OFF" (second state) to "P2" (ninth state); or is controlled to be turned on or off at a constant period (PWM controlled state) ("PWM"), i.e., changes from "PWM" (third state) to "P1" (eighth state). Each stage 1 to 6 is further divided into three sections A'', B'', and C''. An individual energization pattern is set for sections A'', B'', and C''. The duration (electrical angle) of intervals A'', B'', and C'' changes depending on the advance angle value and the energization angle value. Here, in Figure 6, the "P1" state is denoted as "PWM phase (indicated Duty)" and the "P2" state is denoted as "PWM phase (1 / 2 Duty)".

[0066] For example, in stage 1 enclosed by hole edge HE1 and hole edge HE2, the energizing pattern in section A'' is a combination of switching elements 51a to 51f, each being "1", "0", "P1", "P1", "P2", and "P2". Also, the energizing pattern in section B'' is a combination of switching elements 51a to 51f, each being "1", "0", "P1", "P1", "1", and "0". Furthermore, the energizing pattern in section C'' is a combination of switching elements 51a to 51f, each being "P2", "P2", "P1", "P1", "1", and "0".

[0067] Furthermore, Figure 7 is a table summarizing an example of the free-resistance energizing pattern of the second method shown in Figure 6. The ROM (not shown) in the control unit 40 stores the free-resistance energizing pattern in a format such as that shown in Figure 7. In Figure 7, "P1" represents the eighth state controlled by a PWM signal with an externally input instruction duty cycle, "P2" represents the ninth state controlled by a PWM signal with a duty cycle of half the instruction duty cycle, "1" represents on, and "0" represents off. In this manner, the drive control unit 43 controls the conduction (energy supply) of the switching elements 51a to 51f in the free-resist drive mode (second method) using the free-resist energizing pattern described above.

[0068] As mentioned above, the square wave drive mode is a drive mode of the square wave drive method and is a higher output drive mode than the free-response drive mode. Furthermore, the free-response drive mode is a free-response drive mode in which an intermediate power drive signal is output by PWM control during the open-circuit period of the phases that are not energized among the multiple phase drive signal lines that drive the motor 2, and is a drive mode with lower output than the square wave drive mode. Here, the intermediate power drive signal is a PWM signal with a duty cycle intermediate between the PWM signal with the maximum duty cycle and the PWM signal with the minimum duty cycle (first method), or a PWM signal with a duty cycle of 1 / 2 of the externally input instruction duty cycle (second method).

[0069] Returning to the explanation of Figure 1, the drive control unit 43 controls the switching between the free-response drive mode and the square wave drive mode based on the vehicle speed detected by the vehicle speed detection unit 42. The drive control unit 43 switches from the free-response drive mode to the square wave drive mode when the vehicle speed becomes equal to or greater than a predetermined square wave threshold Vth1 (first threshold or higher). Also, the drive control unit 43 switches from the square wave drive mode to the free-response drive mode when the vehicle speed becomes equal to or less than the free-response threshold Vth2 (second threshold or lower), which is lower than the square wave threshold Vth1 (first threshold). Now, with reference to Figure 8, the square wave threshold Vth1 and the free-response threshold Vth2 will be explained.

[0070] Figure 8 shows an example of the drive mode switching operation of the motor control device 150 according to this embodiment. In Figure 8, the horizontal axis represents time, and the vertical axis represents vehicle speed. Waveform W1 shows an example of the change in vehicle speed over time. Periods TR1 and TR3 represent the periods of the free-response drive mode, and period TR2 represents the period of the square wave drive mode.

[0071] As shown in Figure 8, when the vehicle speed increases and exceeds the square wave threshold Vth1, the drive control unit 43 switches from the free-response drive mode to the square wave drive mode. Also, when the vehicle speed decreases and falls below the free-response threshold Vth2, the drive control unit 43 switches from the square wave drive mode to the free-response drive mode. Here, the square wave threshold Vth1 is a value within the range of 1.1 to 6.6 times the free-resistance threshold Vth2.

[0072] Next, the operation of the motor control device 150 according to this embodiment will be described with reference to the drawings. Figure 9 is a flowchart showing an example of the drive mode switching operation of the motor control device 150 according to this embodiment.

[0073] As shown in Figure 9, the control unit 40 of the motor control device 150 first detects the vehicle speed (step S101). The vehicle speed detection unit 42 of the control unit 40 detects the vehicle speed based on the vehicle speed signal output from the ECU 4.

[0074] Next, the drive control unit 43 of the control unit 40 determines whether the drive mode of the motor 2 is the free-response drive mode (step S102). If the drive mode is the free-response drive mode (step S102: YES), the drive control unit 43 proceeds to step S103. If the drive mode is not the free-response drive mode (step S102: NO), the drive control unit 43 proceeds to step S107.

[0075] In step S103, the drive control unit 43 determines whether the vehicle speed is greater than or equal to the square wave threshold Vth1 (vehicle speed ≥ square wave threshold Vth1). If the vehicle speed is greater than or equal to the square wave threshold Vth1 (step S103: YES), the drive control unit 43 proceeds to step S104. If the vehicle speed is less than the square wave threshold Vth1 (step S103: NO), the drive control unit 43 returns to step S101.

[0076] In step S104, the drive control unit 43 switches from the free-response drive mode to the square wave drive mode. Next, the drive control unit 43 initializes the cumulative point value (load integrated value) (step S105). The drive control unit 43 initializes the load integrated value generated by the load integrated value generation unit 41 (returns it to "0").

[0077] Next, the drive control unit 43 deactivates the energy mode (step S106). Here, the energy mode is a protection mode that limits the output when the load cumulative value becomes very large (when the load becomes large). After the processing in step S106, the drive control unit 43 returns to the process in step S101.

[0078] In step S107, the drive control unit 43 determines whether the vehicle speed is less than or equal to the free-resistance threshold Vth2 (vehicle speed ≤ free-resistance threshold Vth2). If the vehicle speed is less than or equal to the free-resistance threshold Vth2 (step S107: YES), the drive control unit 43 proceeds to step S108. If the vehicle speed is greater than the free-resistance threshold Vth2 (step S107: NO), the drive control unit 43 returns to step S101.

[0079] In step S108, the drive control unit 43 switches from the free-response drive mode to the square wave drive mode. Next, the drive control unit 43 initializes the cumulative point value (load integrated value) (step S109). The drive control unit 43 initializes the load integrated value generated by the load integrated value generation unit 41 (returns it to "0").

[0080] Next, the drive control unit 43 cancels the energy mode (step S110). After the process in step S110, the drive control unit 43 returns to step S101.

[0081] Furthermore, with reference to Figure 10, the operation of switching the drive mode when the vehicle speed signal cannot be detected will be explained. Figure 10 is a flowchart showing another example of the drive mode switching operation of the motor control device 150 according to this embodiment.

[0082] As shown in Figure 10, the drive control unit 43 of the motor control device 150 first checks for an abnormality in the vehicle speed signal (step S201). Next, the drive control unit 43 determines whether or not there is an abnormality in the vehicle speed signal (step S202). That is, the drive control unit 43 determines whether or not the vehicle speed can be detected normally. If there is an abnormality in the vehicle speed signal (vehicle speed cannot be detected) (step S202: YES), the drive control unit 43 proceeds to step S203. Also, if there is no abnormality in the vehicle speed signal (step S202: NO), the drive control unit 43 proceeds to step S203.

[0083] In step S203, the drive control unit 43 changes to square wave drive mode as an emergency operation. After the processing in step S203, the drive control unit 43 returns to the processing in step S201.

[0084] Furthermore, in step S204, the drive control unit 43 cancels the emergency operation. After the processing in step S204, the drive control unit 43 returns the process to step S201.

[0085] Next, with reference to Figure 11, a modified example of the drive mode switching operation of the motor control device 150 according to this embodiment will be described. Figure 11 is a flowchart showing a modified example of the switching operation of the drive mode of the motor control device according to this embodiment. Here, a modified example is described when the vehicle speed threshold described above is equal in value to the rectangular wave threshold Vth1 and the free-resistance threshold Vth2.

[0086] As shown in Figure 11, the control unit 40 of the motor control device 150 first detects the vehicle speed (step S301). The vehicle speed detection unit 42 of the control unit 40 detects the vehicle speed based on the vehicle speed signal output from the ECU 4.

[0087] Next, the drive control unit 43 of the control unit 40 determines whether the vehicle speed is greater than or equal to the threshold Vth3 (vehicle speed ≥ threshold Vth3) (step S302). If the vehicle speed is greater than or equal to the threshold Vth3 (step S302: YES), the drive control unit 43 proceeds to step S303. If the vehicle speed is less than the threshold Vth3 (step S302: NO), the drive control unit 43 proceeds to step S304.

[0088] In step S303, the drive control unit 43 changes to square wave drive mode. After the processing in step S303, the drive control unit 43 proceeds to step S305. Furthermore, in step S304, the drive control unit 43 changes to free-response drive mode. After the processing in step S304, the drive control unit 43 proceeds to step S305.

[0089] In step S305, the drive control unit 43 determines whether or not the drive mode has been changed. If the drive mode has been changed (step S305: YES), the drive control unit 43 proceeds to step S306. If the drive mode has not been changed (step S305: NO), the drive control unit 43 returns to step S301.

[0090] In step S306, the drive control unit 43 initializes the cumulative point value (load integrated value). The drive control unit 43 initializes the load integrated value generated by the load integrated value generation unit 41 (returns it to "0").

[0091] Next, the drive control unit 43 cancels the energy mode (step S307). After the processing in step S110, the drive control unit 43 returns to the process in step S301.

[0092] As described above, the drive control unit 43 may switch to the square wave drive mode when the vehicle speed is equal to or greater than a predetermined threshold Vth3, and switch to the free-response drive mode when the vehicle speed is less than the threshold Vth3 (less than a predetermined threshold).

[0093] Next, with reference to Figure 12, an example of applying the motor device 100 described above to a wiper device will be explained. Figure 12 is a configuration diagram showing an example of a wiper device 200 according to this embodiment.

[0094] As shown in Figure 12, the wiper device 200 performs a wiping operation on the window surface of the vehicle 1's window glass 10. The wiper device 200 comprises a motor device 100, a linkage mechanism 11, two wiper arms 12, and wiper blades 13 attached to the tips of each wiper arm 12.

[0095] The motor device shown in Figure 12 is the motor device 100 of the embodiment described above, and a detailed explanation thereof is omitted here. The motor device 100 comprises a motor 2 and a motor control device 150.

[0096] The wiper arm 12 moves across the window surface of the window glass 10 by the rotational drive of the motor device 100, and performs a wiping action with the wiper blade 13 attached to its tip. The two wiper arms 12 are connected by a linkage mechanism 11.

[0097] The wiper blade 13 is positioned 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 in a blade holder attached to the tip of the wiper arm 12. When the wiper arm 12 is oscillated 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).

[0098] As described above, the motor control device 150 according to this embodiment is a motor control device that controls a motor 2 having a rotor shaft 22a (output shaft), and comprises a vehicle speed detection unit 42 and a drive control unit 43. The vehicle speed detection unit 42 detects the vehicle speed, which is the travel speed of the vehicle on which the motor 2 is mounted. The drive control unit 43 controls the motor 2 to switch between a free-response drive mode (first drive mode) and a square wave drive mode (second drive mode), which is a high-output drive mode in which the minimum rotational speed at which the output shaft can be rotated by the input power is higher than that of the free-response drive mode (first drive mode), based on the vehicle speed detected by the vehicle speed detection unit 42. Here, the second drive mode is a high-output drive mode in which the rotational speed and output of the motor 2 are higher than those of the first drive mode at the same load, power, and duty cycle.

[0099] Furthermore, in the motor control device 150 according to this embodiment, the load on the motor 2 tends to increase as the vehicle speed increases, for example, when applied to a wiper device 200. Therefore, the motor control device 150 according to this embodiment can properly drive the motor even when a high load occurs from the initial stage of operation. In other words, the motor control device 150 according to this embodiment can perform the wiping operation without stopping, even for the first wipe immediately after the wiper is activated while the vehicle is in motion.

[0100] Furthermore, the motor control device 150 according to this embodiment can appropriately switch to the free-response drive mode (first drive mode) when the vehicle is stopped, thereby reducing the drive noise (reducing motor operating noise).

[0101] Furthermore, in this embodiment, the drive control unit 43 switches from the free-response drive mode (first drive mode) to the square wave drive mode (second drive mode) when the vehicle speed becomes equal to or greater than a predetermined square wave threshold Vth1 (first threshold or greater). Also, the drive control unit 43 switches from the square wave drive mode (second drive mode) to the free-response drive mode (first drive mode) when the vehicle speed becomes equal to or less than the free-response threshold Vth2 (second threshold or less), which is lower than the square wave threshold Vth1.

[0102] As a result, the motor control device 150 according to this embodiment switches to a square wave drive mode (second drive mode) when the vehicle speed is high (high load) and switches to a free-resist drive mode (first drive mode) when the vehicle speed is low (low load). This makes it possible to reduce motor operating noise when the load is low and to ensure reliable motor drive when the load is high. Furthermore, by using two thresholds, a square wave threshold Vth1 and a free-resist threshold Vth2, the motor control device 150 according to this embodiment can reduce malfunctions such as frequent switching of the drive mode due to noise.

[0103] Furthermore, in this embodiment, the square wave threshold Vth1 is a value within the range of 1.1 to 6.6 times the free-resistance threshold Vth2. As a result, the motor control device 150 according to this embodiment can appropriately handle vehicles such as automobiles traveling at high speeds of 200 km / h or more.

[0104] Furthermore, in this embodiment, the second drive mode described above is the square wave drive mode (square wave drive mode), and the first drive mode described above is the free-less drive mode (free-less drive mode). The free-less drive mode (free-less drive mode) is a mode in which a drive signal of intermediate power is output by PWM control during the open-circuit period (free period) of the phases that are not energized among the multiple phase drive signal lines that drive the motor 2. The drive control unit 43 switches from the free-less drive mode to the square wave drive mode when the vehicle speed becomes equal to or greater than the square wave threshold Vth1. Also, the drive control unit 43 switches from the square wave drive mode to the free-less drive mode when the vehicle speed becomes equal to or less than the free-less threshold Vth2. As a result, the motor control device 150 according to this embodiment can appropriately switch between a rectangular wave drive mode and a free-response drive mode depending on the vehicle speed.

[0105] Furthermore, in this embodiment, the intermediate power drive signal described above is either a PWM signal with a duty cycle intermediate between the maximum duty cycle PWM signal and the minimum duty cycle PWM signal (first method), or a PWM signal with a duty cycle of half the externally inputted instruction duty cycle (second method). As a result, the motor control device 150 according to this embodiment can appropriately perform motor driving in free-response mode.

[0106] Furthermore, in this embodiment, the motor 2 is a brushless motor having three phase windings (21u, 21v, 21w). The drive control unit 43 controls the conduction of a plurality of switching elements 51a to 51f of the inverter 50 that generates the three phase drive signal by switching between a brushless drive mode (first drive mode) and a square wave drive mode (second drive mode). As a result, the motor control device 150 according to this embodiment can perform more appropriate motor driving for a brushless motor.

[0107] Furthermore, in this embodiment, the drive control unit 43 may switch to a square wave drive mode (second drive mode) when the vehicle speed is equal to or greater than a predetermined threshold Vth3, and switch to a free-response drive mode (first drive mode) when the vehicle speed is less than the threshold Vth3. As a result, the motor control device 150 according to this embodiment can achieve both a reduction in motor operating noise when the load is small and reliable motor drive when the load is large.

[0108] Furthermore, in this embodiment, the drive control unit 43 resets the cumulative point value (load cumulative value) to "0" when the operating mode is switched. As a result, the motor control device 150 according to this embodiment can reduce the occurrence of errors in the cumulative point value (load cumulative value) and malfunctions that occur when switching drive modes.

[0109] Furthermore, in this embodiment, when the operating mode is switched, the drive control unit 43 releases the energy mode, which is a protection mode that limits the output, if the cumulative point value (load cumulative value) becomes very large (the load becomes large). As a result, the motor control device 150 according to this embodiment can reduce the likelihood of malfunctions occurring due to being in protection mode when switching drive modes.

[0110] Furthermore, in this embodiment, if the vehicle speed cannot be detected, the drive control unit 43 switches to the square wave drive mode (second drive mode) as an emergency operation. As a result, the motor control device 150 according to this embodiment can reliably drive the motor by switching to the square wave drive mode (second drive mode) when an abnormality occurs.

[0111] Furthermore, the motor device 100 according to this embodiment comprises a motor 2 and the motor control device 150 described above. As a result, the motor device 100 according to this embodiment has the same effect as the motor control device 150, and can properly drive the motor even when a high load is generated from the initial stage of motor operation.

[0112] Furthermore, the wiper device 200 according to this embodiment includes a motor 2 and the motor control device 150 described above. The motor control device 150 uses the motor 2 to cause the wiper members (wiper arm 12 and wiper blade 13) to perform a wiping operation on the windshield.

[0113] As a result, the wiper device 200 according to this embodiment has the same effect as the motor device 100 described above, and the motor can be driven properly even when a high load is generated from the initial stage of motor operation.

[0114] Furthermore, the motor control method according to this embodiment is a motor control method for controlling a motor 2 having a rotor shaft 22a, and includes a vehicle speed detection step and a drive control step. In the vehicle speed detection step, the vehicle speed detection unit 42 detects the vehicle speed, which is the travel speed of the vehicle on which the motor 2 is mounted. In the drive control step, the drive control unit 43 controls the motor 2 to switch between a free-response drive mode (first drive mode) and a square wave drive mode (second drive mode) based on the vehicle speed detected in the vehicle speed detection step. The square wave drive mode (second drive mode) is a high-output drive mode in which the minimum rotational speed at which the rotor shaft 22a can be rotated by the input power is higher than that of the free-response drive mode (first drive mode).

[0115] As a result, the wiper device 200 according to this embodiment has the same effect as the motor device 100 described above, and the motor can be driven properly even when a high load is generated from the initial stage of motor operation.

[0116] It should be noted that the present invention is not limited to the embodiments described above, and can be modified without departing from the spirit of the invention. For example, in the above embodiment, an example was described in which the motor control device 150 switches the drive mode according to the vehicle speed, but it is not limited to this, and the drive mode may be switched by combining the vehicle speed and the cumulative point value (load cumulative value).

[0117] Furthermore, although the above embodiment describes an example of switching between a free-resist drive mode (first drive mode) and a square wave drive mode (second drive mode), it is not limited to this, and other drive modes may be switched.

[0118] Furthermore, although the above embodiment describes an example in which the motor device 100 is used in a wiper device 200, the motor device 100 may be used for other purposes.

[0119] Furthermore, each component of the motor device 100 described above has a computer system inside. The processing of each component of the motor device 100 may be performed by recording a program for realizing the functions of each component of the motor device 100 onto a computer-readable recording medium, loading the program recorded on this recording medium into the computer system, and executing it. Here, "loading the program recorded on the recording medium into the computer system and executing it" includes installing the program into the computer system. Here, "computer system" includes hardware such as the operating system and peripheral devices. Furthermore, "computer system" may include multiple computer devices connected via a network, including communication lines such as the Internet, WAN, LAN, and dedicated lines. "Computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Thus, the recording medium storing the program may be a non-transient recording medium such as a CD-ROM.

[0120] Furthermore, some or all of the above-mentioned functions may be implemented as integrated circuits such as LSIs (Large Scale Integrations). Each of the above-mentioned functions may be implemented as an individual processor, or some or all of them may be integrated into a single processor. In addition, the method of implementing integrated circuits is not limited to LSIs; they may also be implemented using dedicated circuits or general-purpose processors. Furthermore, if advances in semiconductor technology lead to the emergence of integrated circuit technologies that can replace LSIs, integrated circuits using such technologies may be used.

[0121] 1...Vehicle, 2...Motor, 3...Battery, 4...ECU, 10...Window glass, 11...Link mechanism, 12...Wiper arm, 13...Wiper blade, 21...Stator, 21u, 21v, 21w...Winding, 22...Rotor, 22a...Rotor shaft, 22b...Permanent magnet, 30...Position detection unit, 30u, 30v, 30w...Hall element, 40...Control unit, 41...Load integrated value generation unit, 42...Vehicle speed detection unit, 43...Drive control unit, 50...Inverter, 51a~51f...Switching element, 52a~52f...Diode, 100...Motor device, 150...Motor control device, 200...Wiper device

Claims

1. A motor control device for controlling a brushless motor having an output shaft not used for powering a vehicle and three-phase windings, A vehicle speed detection unit detects the vehicle speed, which is the travel speed of the vehicle on which the brush motor is mounted, A drive control unit performs control to switch between a first drive mode, in which the brushless motor is driven based on the vehicle speed detected by the vehicle speed detection unit, and a second drive mode, in which the rotational speed of the output shaft and the output of the brushless motor are higher than those of the first drive mode. Equipped with, The drive control unit, The conduction of multiple switching elements in an inverter that generates a three-phase drive signal is controlled by switching between the first drive mode and the second drive mode. When the vehicle speed exceeds a predetermined first threshold, the system switches from the first drive mode to the second drive mode. When the vehicle speed falls below a second threshold, which is lower than the first threshold, the system switches from the second drive mode to the first drive mode. The second drive mode described above is a square wave drive mode, The first drive mode is a brushless drive mode in which, among the three-phase drive signal lines that drive the brushless motor, a drive signal with an intermediate duty cycle is output by PWM (Pulse Width Modulation) control during the open-circuit period of the phase that is not energized in the square wave drive mode, a drive signal with the maximum duty cycle is output to one of the other two-phase drive signal lines, and a drive signal with the minimum duty cycle is output to the other of the other two-phase drive signal lines. The intermediate duty cycle is set to a value between the maximum duty cycle and the minimum duty cycle. The drive control unit, When the vehicle speed exceeds the first threshold, the drive mode switches from the free-resist drive mode to the square wave drive mode. When the vehicle speed falls below the second threshold, the system switches from the rectangular wave drive mode to the free-response drive mode. Motor control device.

2. With respect to the second threshold, the first threshold is a value within the range of 1.1 to 6.6 times. The motor control device according to claim 1.

3. The aforementioned brush motor and, A motor control device according to claim 1 or claim 2 and A motor device equipped with the following features.

4. The aforementioned brush motor and, A motor control device according to claim 1 or claim 2 and Equipped with, The motor control device uses the brushless motor to cause the wiper member to perform a wiping operation on the wind surface. Wiper device.

5. A motor control method for controlling a brushless motor having an output shaft not used for powering a vehicle and three-phase windings, The vehicle speed detection unit performs a vehicle speed detection step in which it detects the vehicle speed, which is the driving speed of the vehicle on which the brushless motor is mounted, A drive control step in which the drive control unit performs control to switch between a first drive mode in which the brushless motor is driven based on the vehicle speed detected by the vehicle speed detection step, and a second drive mode in which the rotational speed of the output shaft and the output of the brushless motor are higher than those of the first drive mode. Includes, In the drive control step, the drive control unit, The conduction of multiple switching elements in an inverter that generates a three-phase drive signal is controlled by switching between the first drive mode and the second drive mode. When the vehicle speed exceeds a predetermined first threshold, the system switches from the first drive mode to the second drive mode. When the vehicle speed falls below a second threshold, which is lower than the first threshold, the system switches from the second drive mode to the first drive mode. The second drive mode described above is a square wave drive mode, The first drive mode is a brushless drive mode in which, among the three-phase drive signal lines that drive the brushless motor, a drive signal with an intermediate duty cycle is output by PWM (Pulse Width Modulation) control during the open-circuit period of the phase that is not energized in the square wave drive mode, a drive signal with the maximum duty cycle is output to one of the other two-phase drive signal lines, and a drive signal with the minimum duty cycle is output to the other of the other two-phase drive signal lines. The intermediate duty cycle is set to a value between the maximum duty cycle and the minimum duty cycle. In the drive control step, the drive control unit, When the vehicle speed exceeds the first threshold, the drive mode switches from the free-resist drive mode to the square wave drive mode. When the vehicle speed falls below the second threshold, the system switches from the rectangular wave drive mode to the free-response drive mode. Motor control method.

Images