JP7221166B2 - Brushless motor, brushless motor control method, and wiper device control method - Google Patents

Description

The present invention relates to a brushless motor, a brushless motor control method, and a wiper device control method.

Patent Document 1 applies for a control method for outputting 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 in brushless motor drive. . This control method is hereinafter referred to as freeless drive/energization.

Although this freeless drive/energization method reduces the motor operating noise, there is a problem that the characteristics of the motor are degraded compared to the rectangular wave energization method.

JP 2017-103925 A

Therefore, if a wiper device for swinging the wiper arm is designed using the brushless motor that performs the freeless drive/energization method described in Patent Document 1, there is a possibility that the wiper will not be able to wipe the wiper when the brushless motor is in a high load state. be. That is, in the freeless drive/energization method described in Patent Document 1, the characteristics of the motor are degraded compared to the rectangular wave energization method.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and provides a brushless motor, a brushless motor control method, and a wiper device control method that can appropriately switch between freeless energization control and rectangular wave energization control. for the purpose.

In order to solve the above problems, one aspect of the present invention includes a stator having three-phase windings, a rotor having permanent magnets, and rotating facing the stator, and a plurality of switching elements, An inverter that supplies alternating current to the three-phase winding by turning on or off a plurality of switching elements, and an energization pattern that represents changes in the energization state of each phase of the three-phase winding according to the rotation of the rotor. a control unit that switches to a freeless energization pattern or a rectangular wave energization pattern to control the ON or OFF state of the plurality of switching elements, wherein the control unit includes a load integration determined according to the load of the rotor. When the value is less than a predetermined first threshold, the energization pattern is switched to the freeless energization pattern, and when the load integrated value is equal to or greater than the predetermined first threshold, the energization pattern is changed to the rectangular wave energization pattern. It is a switching brushless motor.

An aspect of the present invention is the brushless motor, wherein the rectangular wave energization pattern is a first state in which the switching element is continuously turned on, or a first state in which the switching element is continuously turned off. a second state in which the switching element is under PWM control, or a third state in which the switching element is PWM-controlled; In a fourth state in which PWM control is performed by a PWM signal with a maximum duty ratio greater than or in a state in which the switching element is PWM-controlled by a PWM signal with a minimum duty ratio smaller than the PWM control in the third state It includes an energization pattern that is a combination of a certain fifth state, or a sixth state that is PWM-controlled by a PWM signal with an intermediate duty ratio between the maximum duty ratio and the minimum duty ratio.

An aspect of the present invention is the brushless motor, wherein the rectangular wave energization pattern is a first state in which the switching element is continuously turned on, or a first state in which the switching element is continuously turned off. The freeless energization pattern includes a energization pattern that is a combination of a second state that is a state in which the switching element is continuously turned on, or a third state that is a state that is PWM controlled. A certain seventh state, or an eighth state in which the switching element is PWM-controlled by a PWM signal having a designated duty ratio input from the outside, or a PWM signal having a duty ratio of 1/2 of the designated duty ratio. It includes an energization pattern that is any combination of a ninth state that is a controlled state.

Further, according to one aspect of the present invention, there is provided the above brushless motor, wherein the control unit reduces the load integrated value to the predetermined first threshold value after the load integrated value becomes equal to or greater than the predetermined first threshold value. is less than a predetermined second threshold, the energization pattern is switched to the freeless energization pattern.

Further, one aspect of the present invention is the brushless motor described above, wherein the load integrated value constitutes a power supply voltage supplied to the inverter, a rotation speed of the rotor, and a freeless energization pattern or a rectangular wave energization pattern. It is a value obtained by detecting the duty ratio of the PWM signal in the PWM controlled state among the energized states, and the duty ratio of the PWM signal at predetermined intervals, and accumulating the load point value calculated based on the detected three values.

Further, one aspect of the present invention includes a stator having three-phase windings, a rotor having permanent magnets and rotating facing the stator, and a plurality of switching elements, wherein the plurality of switching elements are An inverter that supplies alternating current to the three-phase windings by turning it on or off, and an energization pattern that represents changes in the energization state of each phase of the three-phase windings according to the rotation of the rotor is referred to as a freeless energization pattern or an energization pattern. a control unit for switching to a rectangular wave energization pattern to control the ON or OFF state of the plurality of switching elements, wherein the control unit determines according to the load of the rotor. is less than a predetermined first threshold, the energization pattern is switched to the freeless energization pattern, and when the load integrated value is equal to or greater than the predetermined first threshold, the energization pattern is changed to the rectangular A brushless motor control method that switches to a wave conduction pattern.

According to another aspect of the present invention, there is provided a control method for a wiper device including the brushless motor, a wiper arm that is swung by the brushless motor, and a wiper blade that is connected to the wiper arm and that reciprocally wipes a wiping area of a vehicle. In the wiper device control method, the control unit switches the energization pattern when the position of the wiper blade is at the reverse position in the wiping area.

Further, one aspect of the present invention is the control method for the wiper device, wherein the control unit counts the number of wiping times of the wiper blade in the rectangular wave energization pattern, and when the number of wiping times is equal to or greater than a predetermined value Then, the rectangular wave energization pattern is switched to the freeless energization pattern.

According to the present invention, it is possible to appropriately switch between the freeless energization control and the rectangular wave energization control according to the load integrated value determined according to the rotor load.

It is a mimetic diagram showing a wiper device concerning one embodiment of the present invention. 2 is a configuration diagram showing a configuration example of a brushless motor 1a shown in FIG. 1; FIG. 3 is a block diagram showing the configuration of a high load detection processing system in the control unit 12; FIG. FIG. 4 is an explanatory diagram showing the configuration of a load point map 12b; FIG. 4 is an explanatory diagram showing the configuration of a load point map 12b; FIG. 3 is an explanatory diagram showing the relationship between a cumulative point value (integrated load value), a threshold value, and an operating state of a brushless motor 1a; It is a figure for demonstrating an example of a rectangular wave energization pattern. An example of the rectangular wave energization pattern shown in FIG. 7 is summarized as a table. It is a figure for demonstrating an example of the freeless energization pattern which concerns on 1st Embodiment. An example of the freeless energization pattern shown in FIG. 9 is summarized as a table. FIG. 11 is a diagram for explaining an example of a freeless energization pattern according to the second embodiment; An example of the freeless energization pattern shown in FIG. 11 is summarized as a table. 4 is a flow chart showing an example of an energization control switching operation by a control unit 12; 9 is a flowchart showing another example of an energization control switching operation by the control unit 12;

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of a wiper device 10 according to one embodiment of the present invention. The wiper device 10 shown in FIG. 1 has a wiper arm 3a on the side of the driver's seat and a wiper arm 3b on the side of the passenger's seat which are swingably provided on the vehicle body. A wiper blade 4a on the driver's seat side and a wiper blade 4b on the passenger's seat side are attached to each of the wiper arms 3a and 3b. The wiper blades 4a and 4b are pressed against the windshield 300 by spring members (not shown) installed in the wiper arms 3a and 3b. The vehicle body is provided with two wiper shafts 9a and 9b, and the wiper arms 3a and 3b are attached at their proximal ends to the wiper shafts 9a and 9b, respectively.

The wiper device 10 is provided with two motor devices 100a and 100b for the oscillating movement of the wiper arms 3a and 3b. In the wiper device 10, the two motor devices 100a and 100b are synchronously controlled for forward and reverse rotation, so that the wiper blades 4a and 4b swing in the wiping ranges 5a and 5b indicated by dashed lines. The motor device 100a is composed of a brushless motor (hereinafter sometimes simply referred to as a motor) 1a and a speed reduction mechanism 2a. The motor device 100b is composed of a brushless motor 1b and a reduction mechanism 2b. The brushless motor 1a is connected to an ECU 200, which is a vehicle-side controller, via an in-vehicle LAN (Local Area Network) 400. FIG. Switch information such as wiper switch ON/OFF, Lo, Hi, and INT (intermittent operation), engine start information, vehicle speed information, and the like are input from the ECU 200 to the brushless motor 1a via the in-vehicle LAN 400 . A communication line 500 is connected between the brushless motors 1a and 1b. In the wiper device 10 shown in FIG. 1, the brushless motors 1a and 1b cooperate to control the operation of the wiper blades 4a and 4b by transmitting and receiving predetermined information via the communication line 500. FIG. The brushless motor 1a and the brushless motor 1b differ in part of the contents of the programs and the like, but the basic configuration can be the same.

Next, a configuration example of the brushless motor 1a shown in FIG. 1 will be described with reference to FIG. The brushless motor 1a includes an inverter 11, a control section 12, a rotor 13, a stator 14, and hall sensors 15u, 15v and 15w.

The stator 14 has a stator core (not shown) and windings 14u, 14v and 14w wound in a plurality of slots of the stator core. Windings 14u, 14v and 14w are delta-connected three-phase windings. However, not only delta connection but also star connection may be used.

The rotor 13 rotates while a rotating shaft and a plurality of permanent magnets are fixed in the circumferential direction of the rotating shaft and arranged inside the stator 14 so as to face each other. The rotor 13 may be an outer rotor type structure located outside the stator 14 . The structures of the rotor 13 and the stator 14 are not limited. .

The Hall sensors (position detectors) 15u, 15v and 15w use Hall elements to detect the rotational position of a plurality of permanent magnets fixed to the rotor 13 or a magnet fixed on the rotating shaft of the rotor and having a plurality of magnetic poles. Detect and output the detected result. Hall sensors 15u, 15v and 15w detect positions shifted by 120 electrical degrees. The Hall sensors 15u, 15v, and 15w are digital signals obtained by converting, for example, analog signals having magnitudes proportional to magnetic fields generated using Hall elements into high-level (H-level) or low-level (L-level) signals by means of comparators. is output to the control unit 12 . In this embodiment, the Hall sensor 15u outputs a digital signal (position detection signal Hu) corresponding to the U phase, the Hall sensor 15v outputs a digital signal (position detection signal Hv) corresponding to the V phase, and the Hall sensor 15w outputs a digital signal (position detection signal Hw) corresponding to the W phase. The Hall sensors 15u, 15v and 15w of this embodiment change the output of the inverter 11 immediately at each position where the level of the output signal of the Hall sensor 15u, 15v or 15w changes, that is, at each position where an edge occurs in the output signal. It is installed with respect to the rotor 13 so that the lead angle is 30 degrees in electrical angle.

Inverter 11 has a plurality of switching elements UH, UL, VH, VL, WH, and WL, and uses external power supply 600 as a DC power supply to switch the plurality of switching elements UH, UL, VH, VL, WH, and WL in a predetermined combination. By turning on or off, an alternating current is supplied to the three-phase windings 14u, 14v and 14w. External power source 600 includes, for example, a battery, a capacitor, and the like mounted on the vehicle. In the example shown in FIG. 2, the six switching elements UH, UL, VH, VL, WH and WL are composed of n-channel MOSFETs (metal oxide semiconductor field effect transistors). The drains of switching elements UH, VH and WH are commonly connected to the positive electrode of external power supply 600 . The source of the switching element UH is connected to a connection terminal (a U-phase terminal) between the windings 14u and 14w and the drain of the switching element UL. The source of the switching element VH is connected to a connection terminal (referred to as a V-phase terminal) between the windings 14v and 14u and the drain of the switching element VL. The source of the switching element WH is connected to a connection terminal (referred to as a W-phase terminal) between the windings 14w and 14v and the drain of the switching element WL. The switching elements UL, VL, and WL have their respective sources commonly connected to the negative electrode (for example, ground terminal) of the external power supply 600 . The control unit 12 controls the ON/OFF operations of the switching elements UH, UL, VH, VL, WH, and WL.

The control unit 12 includes, for example, a microcomputer having a CPU (central processing unit), RAM (random access memory), ROM (read only memory), etc., and peripheral circuits thereof, and switching elements UH, UL, VH, VL. , WH and WL. Control unit 12 also transmits and receives predetermined information to and from ECU 200 and brushless motor 1b. In addition, the control unit 12 selects a first energization pattern (freeless energization pattern) representing a change in the energization state of the windings 14u, 14v, and 14w of each phase of the three-phase winding according to the rotation of the rotor 13. pattern) or a second energization pattern (rectangular wave energization pattern) to control the on or off states of the plurality of switching elements UH, UL, VH, VL, WH and WL. That is, the control unit 12 controls the switching elements UH, UL, VH, VH, UL, VH, VH, UL, VH, WL, WL, WL, UL, VL, WL, WL, WL, WL based on the position detection signals Hu, Hv, Hw. It outputs drive signals to be applied to the gates of VL, WH and WL.

In the brushless motor 1a, the rotation speed (also referred to as motor speed) of the rotor 13 is detected from position detection signals Hu, Hv and Hw (motor pulses) which are output signals of hall sensors (position detection units) 15u, 15v and 15w. . In addition, when controlling the plurality of switching elements UH, UL, VH, VL, WH, and WL to the ON or OFF state, the control unit 12 controls the PWM ( Pulse width modulation) is used to control the duty ratio (also referred to as duty output value) for each constant cycle. Note that the duty ratio is a value obtained by dividing the ON time in one cycle of the PWM signal output from the control unit 12 by the total value of the ON time and the OFF time.

Further, in the control unit 12, high load detection processing of the rotor 13 is performed based on the rotation speed and duty ratio of the rotor 13 calculated and set in this way. In this control process, the load point value is calculated from the motor speed (rotational speed of the rotor 13) and the duty ratio, and accumulated. , the energization pattern is switched from the first energization pattern (freeless energization pattern) to the second energization pattern (rectangular wave energization pattern). The high load detection process will be described below. The high load detection method described below is based on the method described in Japanese Patent No. 4615885 of which Mitsuba Corporation holds the patent.

FIG. 3 is a block diagram showing the configuration of a high load detection processing system in the control unit 12. As shown in FIG. As shown in FIG. 3, the controller 12 is first provided with a point value calculator 12a that calculates a load point value from the motor speed (rotational speed of the rotor 13) and the duty ratio. The point value calculator 12a accesses the load point map 12b pre-stored in the ROM of the controller 12 and calculates the load point value.

A point value accumulator 12c that accumulates the calculated load point values is provided after the point value calculator 12a. The control unit 12 is also provided with a point value comparison unit 12d that compares the load point value (accumulated load value) accumulated by the point value accumulation unit 12c with the reference value stored in the ROM of the control unit 12. ing. Furthermore, a command section 12e is provided downstream of the point value comparison section 12d to issue an operation command to the inverter 11 in the brushless motor 1a based on the comparison result.

The control unit 12 performs the following high-load detection process at predetermined intervals (for example, 10 ms intervals) when the brushless motor 1a is in operation. First, the motor speed (rotational speed of the rotor 13), duty ratio, and power supply voltage (DC power supply voltage from the external power supply 600 supplied to the inverter 11) are detected. The motor speed is detected using the output signals (motor pulse signals) of the hall sensors 15u, 15v and 15w, and here the period of the motor pulse signals is used as the motor speed. As for the duty ratio, the current duty ratio of the brushless motor 1a that is feedback-controlled based on the motor pulse signal is obtained here.

After obtaining the motor speed, duty ratio, and power supply voltage, the point value calculator 12a refers to the load point map 12b to calculate the load point value. 4 and 5 are explanatory diagrams showing the configuration of the load point map 12b. The load point map 12b is formed with motor speed (Hz) and duty (duty ratio) (%) as parameters for each power supply voltage. FIG. 5 shows the case where the power supply voltage is 15V (load point map 12b-15). In the load point map 12b, point values are set according to the motor speed and duty, and the point values are high when the duty is high due to high load or when the number of revolutions is low.

For example, in the load point map 12b-12 of FIG. 4, when the duty is 80% and the motor speed (motor pulse) is 250 Hz, the load point value is "+10". Even if the duty is the same 80%, when the motor speed is 500Hz, it is determined that the load is light, and the load point value is "0", but when the motor speed is 200Hz, it is determined that the load is heavy. Its value is "+15". Also, even if the motor speed is the same 250Hz, when the duty is 60%, it is judged as a normal load and becomes "0", but when the duty is 100%, it is judged as a heavy load and "+15" is the load. point value. On the other hand, when the motor speed reaches 1000 Hz even when the duty is 80%, the load is judged to be light and the load point value becomes "-5". Note that when the motor is stopped, "-20" is set as the load point value.

On the other hand, when the power supply voltage becomes 15V, the score distribution of the load point map 12b also changes and becomes like the load point map 12b-15. In this case, as the power supply voltage rises, the amount of current increases. Therefore, as shown in FIG. 5, the load point value is "+15" even under the same conditions as described above (Duty: 80%, motor speed: 250 Hz). On the other hand, when the power supply voltage drops, the amount of current decreases. Therefore, in order to cope with the case where the power supply voltage is less than 12V, the load point map 12b is prepared so that the load point value is set to be small even under the same conditions. Although the load point map 12b at low voltage is not shown, it is provided for 10V, 11V, and the like.

The point value calculator 12a accesses such a load point map 12b and acquires a load point value corresponding to the current state of the brushless motor 1a while referring to it. After acquiring the load point value, the point value accumulator 12c integrates the value with the load point values acquired so far. This accumulated accumulated point value is stored in the RAM in the control section 12, and is called from the point value accumulation section 12c at the time of the next processing.

The accumulated point value (integrated load value) becomes a large positive value because + (positive) load point values continue when the high load state continues. On the other hand, when the normal load or light load state continues, the load point value of 0 or - (negative) continues, and thus becomes 0 or less. In this case, when the cumulative point value is 0 or less, it is all 0, and the cumulative point value indicates 0 when the brushless motor 1a is operating normally. Further, when the load is reduced to a controllable range after being in a high load state, the cumulative load point value is gradually decreased and eventually converges to 0 or a small positive value. Therefore, by looking at the cumulative point value, it is possible to know what kind of situation the brushless motor 1a is in at present, and if the value exceeds a certain value, it can be determined that the load is high.

Therefore, when the accumulated point value is obtained, the point value comparison unit 12d in the control unit 12 compares the value with a threshold value (predetermined first threshold value) for determining the high load state. As for this threshold value, the point at which the load becomes high when the threshold value exceeds a certain value is measured in advance by experiments, and is stored in the ROM of the control unit 12 . For example, if the accumulated point value exceeds "100", it can be said that the load state is high, so "100" is set as the threshold value. If the cumulative point value does not exceed the threshold, it is determined that the high load state has not been reached. On the other hand, when the cumulative point value exceeds the threshold value, overload countermeasure processing such as switching of the operation mode is performed.

FIG. 6 is an explanatory diagram showing the relationship between the cumulative point value (integrated load value) and the threshold value and the operating state of the brushless motor 1a. In the brushless motor 1a, for example, as shown in FIG. 6, when operation is performed according to an energization pattern in which the energization pattern is the first energization pattern (freeless energization pattern) and a high load state occurs, the accumulated point value increases and the threshold value S1 (predetermined first threshold) is reached. When the cumulative point value becomes equal to or greater than the threshold S1 (or equal to or greater than a predetermined first threshold), the instruction unit 12e determines that the load is in a high load state. Switch to the second energization pattern (rectangular wave energization pattern).

On the other hand, the cumulative point value subtraction adjustment process is performed until the cumulative point value becomes equal to or less than the threshold value S2 (predetermined second threshold value). The threshold value S2 is set to a value that does not significantly affect the detection of a high load based on the accumulated point value even if the control based on the freeless energization pattern is started from this value. In other words, even if the brushless motor 1a is cooled to some extent and the control is started from the threshold value S2 or from the accumulated point value=0 in the control by the freeless energization pattern, a large amount of heat is generated at the subsequent high load detection time. The threshold S2 is set to a value that does not cause any difference.
That is, when the cumulative point value becomes less than the threshold value S2 (less than the predetermined second threshold value), the instruction unit 12e changes the energization pattern of the brushless motor 1a to the second energization pattern (rectangular wave energization pattern) as the high load handling process. pattern) to the first energization pattern (freeless energization pattern).
As described above, the high load detection method is performed by switching the energization control at the timing of whether or not the integrated load value determined according to the load of the rotor exceeds the threshold values S1 and S2. Alternatively, a shunt resistor may be installed in the motor power supply line, and determination may be made from the motor current value flowing through the grounded shunt resistor.

Next, an example of a rectangular wave energization pattern, an example of a freeless energization pattern according to the first embodiment, and an example of a freeless energization pattern according to the second embodiment will be described with reference to FIGS. 7 to 12. FIG.
7, 9 and 11, examples of the position detection signals Hu, Hv and Hw output by the hall sensors 15u, 15v and 15w and the advance angle and conduction angle in the energization control of the inverter circuit 6 will be described. It is an explanatory view for doing. 7, 9, and 11 show the correspondence between the position detection signals Hu, Hv, and Hw and the angular regions in which the switching element VH is turned on. The horizontal axis represents the rotational position of the magnetic poles of the rotor of the brushless motor 1a in electrical angle. The position detection signals Hu, Hv, and Hw have a phase difference of 120° with each cycle of 360° electrical angle, and change to H or L level every 180°. In this embodiment, the change of the position detection signal Hu from L to H is called a hole edge HE1, and the change from H to L is called a hole edge HE4. A change from L to H of the position detection signal Hv is called a hole edge HE3, and a change from H to L is called a hole edge HE6. A change from L to H in the position detection signal Hw is called a hole edge HE5, and a change from H to L is called a hole edge HE2. Assuming that the position detection signals Hu, Hv and Hw output by the Hall sensors 15u, 15v and 15w do not contain errors (the example shown in FIG. 3 is the case where the position detection signals Hu, Hv and Hw do not contain errors). ), the electrical angle between each hole edge is 60°. Further, the stage between the hole edge HE1 and the hole edge HE2 is referred to as a hall stage 1 (hereinafter, simply referred to as stage 1 (the same shall apply hereinafter)), the stage between the hole edge HE2 and the hole edge HE3 is referred to as stage 2, and the stage between the hole edge HE3 and the hole edge HE3. A stage 3 is called between the hole edges HE4. Stage 4 is defined between hole edge HE4 and hole edge HE5, stage 5 is defined between hole edge HE5 and hole edge HE6, and stage 6 is defined between hole edge HE6 and hole edge HE1.

FIG. 7 is a diagram for explaining an example of a rectangular wave energization pattern. FIG. 7 is a diagram showing the relationship between the position detection signals Hu, Hv and Hw and the energization patterns of the switching elements UH, UL, VH, VL, WH and WL, with the horizontal axis representing the electrical angle. The example of energization control shown in FIG. 7 is a case where the lead angle is 20° and the energization angle is 130°.
The energization pattern is such that the switching elements UH, UL, VH, VL, WH and WL are continuously turned on (“ON”) or continuously turned off “OFF” (“ON” or “PWM , which is also referred to as a free phase period) or a combination of a state controlled to be on or off at a constant cycle (PWM controlled state) (“PWM”). Each stage 1-6 is further divided into three sections A', B' and C' respectively. An energization pattern is set individually for the sections A', B' and C'. The periods (electrical angle) of sections A', B' and C' change depending on the value of the advance angle and the value of the conduction angle.

For example, in the stage 1 surrounded by the hole edge HE1 and the hole edge HE2, the energization pattern of the section A' is such that the switching elements UH, UL, VH, VL, WH and WL are "ON", "OFF" and "PWM , 'PWM', 'OFF', and 'OFF'. Also, the energization pattern of section B′ is such that the switching elements UH, UL, VH, VL, WH and WL are “ON”, “OFF”, “PWM”, “PWM”, “ON” and “OFF” respectively. It's a combination. Also, the energization pattern of section C' is such that the switching elements UH, UL, VH, VL, WH and WL are "OFF", "OFF", "PWM", "PWM", "ON" and "OFF", respectively. It's a combination.

Moreover, FIG. 8 summarizes an example of the rectangular wave energization pattern shown in FIG. 7 as a table. The ROM in the control unit 12 stores rectangular wave energization patterns in a format as shown in FIG. 8, for example. In FIG. 8, "1" indicates ON, "0" indicates OFF, and "P" indicates PWM.

As described above, there are three states (1) to (3) below for the combination that constitutes the rectangular wave energization pattern.
(1) First state: Each of the switching elements UH, UL, VH, VL, WH and WL is continuously turned on (“ON”).
(2) Second state: The switching elements UH, UL, VH, VL, WH and WL are in a state of being continuously turned off (periods other than "ON" or "PWM").
(3) Third state: Each of the switching elements UH, UL, VH, VL, WH and WL is in a state (PWM controlled state) (“PWM”) in which it is controlled to be turned on or off at regular intervals.

Here, there are two methods for controlling driving and energization by the freeless energization pattern. In the first method, the duty ratio of the PWM signal for the switching element connected to the coil of one of the three phases is determined by the duty ratio of each PWM signal for the switching element connected to the coils of the other two phases. set to a value halfway between In the second method, the duty ratio of the PWM signal for the switching element connected to the coil of one of the three phases is set to 1/2 of the instruction duty ratio input from the outside, and the other two phases The duty ratios of the respective PWM signals for the switching elements connected to the coils are set to the same value as the indicated duty ratio and 100%, respectively.

First, as a first embodiment, a freeless energization pattern using the first method will be described. In driving and energization by the freeless energization pattern using the first method, the above states (1) to (3) are changed to the following three states (4) to (6), respectively.
(4) Fourth state: change the first state to a fourth state (hereinafter referred to as "PL" state) PWM-controlled by a PWM signal having a maximum duty ratio greater than that of the PWM control in the third state. .
(5) Fifth state: change the third state to a fifth state (hereinafter referred to as "PS" state) PWM-controlled by a PWM signal with a minimum duty ratio smaller than the PWM control in the third state. .
(6) Sixth state: Change the second state to a sixth state (hereinafter referred to as "PM" state) PWM-controlled by a PWM signal having a duty ratio intermediate between the maximum duty ratio and the minimum duty ratio. do.
In other words, when the U-phase, V-phase, and W-phase coils enter the PM state (sixth state) in the freeless energization pattern, the U-phase, V-phase, and W-phase coils become the OFF phase in the rectangular wave energization pattern. is the same timing as the coil (second state) of .
This solves the problem that the control circuit (control section 12) that drives the switching element malfunctions when a negative voltage is generated at the input terminal of the brushless motor when the energization pattern switches from the first state to the second state. I can handle it. In addition, even at the timing when the 120° rectangular wave energization is free (phase open period: period in the second state), PWM control as in the sixth state results in 180° energization, resulting in commutation. A smoother current waveform can be expected to have the effect of making the driving sound quieter (reducing motor operating noise).

Here, in this embodiment, the intermediate duty ratio is 50%. Also, the maximum duty ratio is a duty ratio obtained by adding a half duty ratio of an instruction duty ratio input from the outside to an intermediate duty ratio. Also, the minimum duty ratio is a duty ratio obtained by subtracting half the indicated duty ratio from the intermediate duty ratio.
For example, when the indicated duty ratio is 80%, the intermediate duty ratio is set to 50% in advance, so the maximum duty ratio is 50+80/2, which is 90%, and the minimum duty ratio is 50-80/2, which is 10%. becomes.
The instruction duty ratio may be stored in advance in the ROM of the control unit 12 by the user.
Here, the switching elements UL, VL, and WL on the negative electrode side receive PWM signals that are opposite in phase to the PWM signals that are input to the switching elements UH, VH, and WH on the positive electrode side. Therefore, the duty ratio of the PWM signal that drives the paired switching element differs between the positive electrode side and the negative electrode side. It is called the duty ratio of the PWM signal that drives the switching element.

FIG. 9 is a diagram for explaining an example of a freeless energization pattern according to the first embodiment. FIG. 9 is a diagram showing the relationship between the position detection signals Hu, Hv and Hw and the energization patterns of the switching elements UH, UL, VH, VL, WH and WL, with the horizontal axis representing the electrical angle. The example of energization control shown in FIG. 9 is a case where the lead angle is 20° and the energization angle is 130°. The energization pattern is such that the switching elements UH, UL, VH, VL, WH, and WL are continuously turned on (“ON”), that is, from “ON” (first state) to “PL” (fourth state). ) and a state of continuously turned off (period other than “ON” or “PWM”), that is, from “OFF” (second state) to “PM” (sixth state) The changed state and the state controlled to be on or off at a constant period (PWM controlled state) (“PWM”), that is, from “PWM” (third state) to “PS” (fifth state) A modified state, and any combination of Each stage 1-6 is further divided into three sections A, B and C respectively. An energization pattern is set for the sections A, B and C individually. The periods (electrical angle) of sections A, B and C change depending on the value of the advance angle and the value of the conduction angle.
Note that each switching element UH, UL, VH, VL, WH, and WL repeats ON and OFF in a state of being PWM-controlled, so the waveform is precisely a rectangular wave having a plurality of unevenness, but FIG. And in FIG. 11 which will be described later, for the sake of convenience, ON/OFF of each switching element UH, UL, VH, VL, WH and WL is not specified, and is indicated as "PWM phase". Here, in FIG. 9, the “PL” state is called “PWM phase (MAX Duty)”, the “PS” state is called “PWM phase (MIN Duty)”, and the “PM” state is called “PWM phase (Duty=50)”. write.

For example, in the stage 1 surrounded by the hole edge HE1 and the hole edge HE2, the energization pattern of the section A is such that the switching elements UH, UL, VH, VL, WH and WL are "PL", "PL" and "PS", respectively. , “PS”, “PM”, and “PM”. Also, the energization pattern of section B is a combination of switching elements UH, UL, VH, VL, WH, and WL, respectively, "PL", "PL", "PS", "PS", "PL", and "PL". is. Also, the energization pattern of section C is a combination of switching elements UH, UL, VH, VL, WH, and WL, respectively, "PM", "PM", "PS", "PS", "PL", and "PL". is.

Moreover, FIG. 10 summarizes an example of the freeless energization pattern shown in FIG. 9 as a table. The ROM in the control unit 12 stores the freeless energization pattern in the format shown in FIG. 10, for example. In FIG. 10, "PL" is the fourth state PWM-controlled by the PWM signal with the maximum duty ratio, "PS" is the fifth state PWM-controlled by the PWM signal with the minimum duty ratio, and "PM" is the maximum duty ratio. 6 respectively represent a sixth state PWM-controlled by a PWM signal with an intermediate duty ratio between the ratio and the minimum duty ratio;

Next, a freeless energization pattern using the second method will be described as a second embodiment. In the driving and energization by the freeless energization pattern using the second method, the above states (1) to (3) are changed to the following three states (7) to (9), respectively. Since the control for each switching element is the same between the state (1) and the state (7), the state does not actually change.
(7) Seventh state: The first state is maintained, and the switching elements UH, UL, VH, VL, WH and WL are continuously turned on (“ON”).
(8) Eighth state: The third state is changed to the eighth state (hereinafter referred to as "P1" state) PWM-controlled by the externally input PWM signal having the designated duty ratio.
(9) Ninth state: The second state is changed to a ninth state (hereinafter referred to as "P2" state) PWM-controlled by a PWM signal having a duty ratio of 1/2 of the instructed duty ratio input from the outside. change.
That is, the timing at which the U-phase, V-phase, and W-phase coils are in the P2 state (the ninth state) in the freeless energization pattern corresponds to the timing when the U-phase, V-phase, and W-phase coils are in the OFF phase in the rectangular wave energization pattern. is the same timing as the coil (second state) of .
This solves the problem that the control circuit (control section 12) that drives the switching element malfunctions when a negative voltage is generated at the input terminal of the brushless motor when the energization pattern switches from the first state to the second state. I can handle it. Also, even at the timing when the 120° square wave energization is free (phase open period: period in the second state), PWM control as in the ninth state results in 180° energization, and during commutation A smoother current waveform can be expected to have the effect of making the driving sound quieter (reducing motor operating noise).
That is, the same effect can be expected by using the drive/energization method based on either of the freeless energization patterns of the first embodiment and the second embodiment.

Here, in this embodiment, the duty ratio in the seventh state is 100%. For example, when the designated duty ratio is 80%, the duty ratio in the eighth state is 80%, and the duty ratio in the ninth state is 40% (80/2). The instruction duty ratio may be stored in advance in the ROM of the control unit 12 by the user.

FIG. 11 is a diagram for explaining an example of a freeless energization pattern according to the second embodiment. FIG. 11 is a diagram showing the relationship between the position detection signals Hu, Hv and Hw and the energization patterns of the switching elements UH, UL, VH, VL, WH and WL, with the horizontal axis representing the electrical angle. The example of energization control shown in FIG. 11 is a case where the lead angle is 20° and the energization angle is 130°. The energization pattern is such that each of the switching elements UH, UL, VH, VL, WH, and WL is continuously turned on (“ON”), that is, in a state in which the “ON” (first state) is maintained (first state). 7 state) and a continuously turned off state (period other than "ON" or "PWM"), that is, changed from "OFF" (second state) to "P2" (ninth state). state and a state controlled to be on or off at a constant cycle (PWM controlled state) (“PWM”), that is, changed from “PWM” (third state) to “P1” (eighth state) state, and any combination of Each stage 1 to 6 is further divided into three sections A'', B'' and C'', respectively.Electricity patterns are set individually for the sections A'', B'' and C''. The periods (electrical angle) of intervals A″, B″ and C″ change depending on the value of the lead angle and the value of the conduction angle. Here, in FIG. , “P2” state is expressed as “PWM phase (1/2 duty)”.

For example, in the stage 1 surrounded by the hole edge HE1 and the hole edge HE2, the energization pattern of the section A'' is such that the switching elements UH, UL, VH, VL, WH and WL are "1", "0", and "P1", respectively. , 'P1', 'P2', and 'P2'. In addition, the energization pattern of the section B'' is such that the switching elements UH, UL, VH, VL, WH and WL are "1", "0", "P1", "P1", "1" and "0" respectively. It's a combination. Also, the energization pattern of section C'' is such that the switching elements UH, UL, VH, VL, WH and WL are "P2", "P2", "P1", "P1", "1" and "0" respectively. It's a combination.

Moreover, FIG. 12 summarizes an example of the freeless energization pattern shown in FIG. 11 as a table. The ROM in the control unit 12 stores the freeless energization pattern in the format shown in FIG. 12, for example. In FIG. 12, "P1" is the eighth state in which PWM control is performed by a PWM signal having a designated duty ratio input from the outside, and "P2" is a PWM control by a PWM signal having a duty ratio of 1/2 of the designated duty ratio. A ninth state, "1" for on and "0" for off, respectively.

Next, a switching operation between rectangular wave energization control and freeless energization control by the control unit 12 will be described with reference to FIG. 13 . FIG. 13 is a flow chart showing an example of the energization control switching operation by the control unit 12 . After starting the operation, the control unit 12 repeatedly executes the process shown in FIG. 13 at regular intervals, for example. Note that the control unit 12 always selects the freeless energization control at the start of operation.

It is determined whether or not the wiper is ON (step S11).
Specifically, the control unit 12 determines whether switch information for turning on the wiper switch has been input to the brushless motor 1a.
If the wiper is not in the ON state (step S11-No), storage/stop processing is performed (step S12).
Specifically, the control unit 12 retracts the wiper arms 3a and 3b to the storage positions provided below the lower reversal positions of the wiping ranges 5a and 5b, and stops the brushless motor 1a.

On the other hand, if the wiper is ON (step S11-Yes), it is determined whether or not the load on the rotor 13 is high (step S13).
Specifically, the point value comparison unit 12d in the control unit 12 determines whether or not the cumulative point value (load integrated value) is equal to or greater than the threshold S1 (predetermined first threshold). Note that when calculating the accumulated point value at this time, the duty ratio in the freeless energization pattern of the first embodiment is the fourth state (“PL” state) and the fifth state (“PS” state). and the 6th state (“PM” state), the temporal average values of the stages 1-6 periods of the three duty ratios are used. However, for example, the duty ratio in the sixth state (“PM” state) of the freeless energization pattern may be used.
In the freeless energization pattern of the second embodiment, three duty ratio stages 1 to 6 in the seventh state, eighth state (“P1” state) and ninth state (“P2” state) or the duty ratio in the ninth state (“P2” state) may be used to calculate the cumulative point value.
If the cumulative point value is less than the threshold S1 (less than the predetermined first threshold) (step S13-No), the freeless energization control is continued (step S14). Specifically, the command unit 12e in the control unit 12 continues the freeless energization pattern, which is the currently switched energization pattern (step S14).

On the other hand, when the cumulative point value is equal to or greater than the threshold S1 (greater than or equal to the predetermined first threshold) (step S13-Yes), rectangular wave energization control is performed. Specifically, the command unit 12e in the control unit 12 switches the energization pattern to the rectangular wave energization pattern (step S15).
Here, when the wiper arms 3a and 3b are switched in the middle of wiping, there is a possibility that the behavior of the wiper arms 3a and 3b is abnormal. This is the timing when it is positioned at (lower inversion position, upper inversion position).

Subsequently, it is determined whether or not the rectangular wave energization control has ended (step S16).
Specifically, the point value comparison unit 12d in the control unit 12 determines whether or not the accumulated point value (integrated load value) is less than the threshold S2 (predetermined second threshold smaller than the first threshold). Note that when calculating the cumulative point value at this time, the duty ratio is set to the first state ("ON" state, the duty ratio of which is 100%) and the second state ("OFF" state) of the rectangular wave energization pattern. , a duty ratio of 0%) and in the third state (“PWM” state, a duty ratio of 0 to 100%), the temporal average values in stages 1 to 6 of the three duty ratios are used. be done. However, for example, the duty ratio in the third state (“PWM” state) of the rectangular wave energization pattern may be used.
Further, when the load of the rotor 13 is the same, the temporal average value of the duty ratio of the rectangular wave energization pattern or the duty ratio in the third state (“PWM” state) is the duty ratio of the freeless energization pattern. Since the value is smaller than the temporal average value or the duty ratio in the sixth state (“PM” state), rectangular wave energization improves motor characteristics more than freeless energization.

If the cumulative point value is equal to or greater than the threshold value S2 (step S16-No), the process returns to step S15 to continue the rectangular wave energization control. On the other hand, if the cumulative point value is less than the threshold value S2 (less than the predetermined second threshold value) (step S16-Yes), the process returns to step S11 to determine whether switch information for turning on the wiper switch has been input.
If the determination result of step S11 is No in step S11, the process of step S12 described above (storage/stop process) is performed.
On the other hand, in the case of step S11-Yes, since the cumulative point value is less than the threshold S1 (less than the predetermined first threshold) at this time, the result of step S13 (step S13-No) causes the processing of step S14 (free less energization control).
That is, the end timing of the rectangular wave energization control is the timing when the load of the rotor 13 becomes low and then the freeless energization control is performed, or the erasure end timing.

As described above, according to the embodiment of the present invention, when the load on the rotor 13 is high, switching from the freeless energization control to the rectangular wave energization control improves the motor characteristics. It is possible to continue wiping without On the other hand, when the load of the rotor 13 is low, the motor operation noise is reduced by switching the rectangular wave energization control, which causes the motor operation noise during the wiping operation to become louder, to the freeless energization control. becomes possible.
That is, according to the embodiment of the present invention, it is possible to appropriately switch between the freeless energization control and the rectangular wave energization control according to the load integrated value determined according to the rotor load.
Further, in step S16, by setting the threshold value S2 of the cumulative point value when switching from the rectangular wave energization control to the freeless energization control to a value smaller than the threshold value S1, even if the load fluctuates greatly, the energization pattern can reduce the frequency of switching to alleviate the sense of discomfort given to the occupant.

Also, FIG. 14 is a flowchart showing another example of the energization control switching operation by the control unit 12 . Steps that are the same as those in the embodiment of FIG. 13 are given the same reference numerals, and description thereof is omitted. This embodiment differs from the flowchart shown in FIG. 13 in that steps S17 and S18 are provided before step S13. Note that the control unit 12 always selects the freeless energization control at the start of operation, as in the embodiment of FIG. 13 .

Here, the control unit 12 detects the rotation speed of the brushless motors 1a, 1b based on the output signals of the hall sensors 15u, 15v, and 15w provided in the brushless motors 1a, 1b. The control unit 12 also detects the rotation angles of the brushless motors 1a and 1b based on output signals from absolute angle sensors (not shown) provided in the brushless motors 1a and 1b. Note that there is a correlation between the rotation speed of the brushless motors 1a and 1b and the rotation speed of the wiper blades 4a and 4b based on the speed reduction ratio and the link operation ratio. , the rotational positions and the number of wipes of the wiper blades 4a and 4b can be calculated.

As shown in FIG. 14, when the wiper is ON (step S11-Yes), the control unit 12 determines whether the number of times of wiping by the rectangular wave energization pattern is 0 or a predetermined value or more (step S17). Here, the number of wiping times by rectangular wave energization starts counting after switching from freeless energization to rectangular wave energization, and is reset when rectangular wave energization is switched to freeless energization in step S22, which will be described later. A predetermined value for the number of times of wiping by rectangular wave energization is set to 10 times, for example.
If the number of times of wiping by the rectangular wave energization pattern is not 0 and is not equal to or greater than the predetermined value (step S17-No), the process returns to step S11 to continue the current energization pattern.
If the number of times of wiping by the rectangular wave energization pattern is 0 or more than the predetermined value (step S17-Yes), the controller 12 determines whether or not the wiper blades 4a and 4b are in the downward reversed position (step S18).
If the wiper blades 4a, 4b are not in the lower reversing position (step S18-No), the current energization pattern is continued until the wiper blades 4a, 4b reach the lower reversing position.
If the wiper blades 4a and 4b are in the lower reversed position (step S18-Yes), the process proceeds to step S13. In step S13, if the cumulative point value is equal to or greater than the threshold value S1 (greater than or equal to the predetermined first threshold value) (step S13-Yes), rectangular wave energization control (step S15) is performed, and the process proceeds to step S16.

Even in the above embodiment, the same effects as those of the embodiment shown in FIG. 13 can be obtained. Furthermore, in step S18, by adding a condition that the switching between the freeless energization and the rectangular wave energization is performed when the wiper blades 4a and 4b are in the lower reversing position, the wiping rhythm caused by the switching of the energization pattern is improved. It is possible to make it difficult for the passenger to notice the change. In the above-described embodiment, the position condition of the wiper blades 4a and 4b in step S18 is described as being in the lower reversing position, but the same effect can be obtained even in the upper reversing position. In addition, when switching from rectangular wave energization to freeless energization, by adding a condition of the number of times of wiping by the rectangular wave energization pattern in step S17, even if the load fluctuates significantly, the switching frequency of the energization pattern can be reduced. It is possible to alleviate discomfort given to the passenger.

In addition, embodiment of this invention is not limited to the above. For example, in the above-described embodiment, the rotor 13 and stator 14, the inverter 11 and the control unit 12 are integrally configured. and the inverter 11 may be configured separately from other components. In the above-described embodiment, the wiper device 10 is provided with the two motor devices 100a and 100b. However, the present invention is not limited to this configuration. 3b may be configured to swing. Also, in the above embodiment, the brushless motors 1a and 1b are used as components of the wiper device 10, but the field of application is not limited to the wiper device.

1a, 1b brushless motor 10 wiper device 100a, 100b motor device 11 inverter UH, UL, VH, VL, WH, WL switching element 12 control unit 12a point value calculation unit 12b load point map 12c point value accumulation unit 12d point value comparison unit 12e Command unit 13 Rotor 14 Stator 14u, 14v, 14w Windings 15u, 15v, 15w Hall sensor

Claims (8)

a stator having three-phase windings;
a rotor having a permanent magnet and rotating facing the stator;
an inverter that has a plurality of switching elements and that turns on or off the plurality of switching elements to pass an alternating current through the three-phase winding;
The ON/OFF states of the plurality of switching elements are controlled by switching an energization pattern representing a change in the energization state of each phase of the three-phase windings according to the rotation of the rotor to a freeless energization pattern or a rectangular wave energization pattern. a control unit that
with
The control unit
When the load integrated value determined according to the load of the rotor is less than a predetermined first threshold, the energization pattern is switched to the freeless energization pattern, and the load integrated value is equal to or greater than the predetermined first threshold. switching the energization pattern to the rectangular wave energization pattern when
brushless motor. The rectangular wave energization pattern is a first state in which the switching element is continuously turned on, a second state in which the switching element is continuously turned off, or a PWM-controlled state. Including an energization pattern that is any combination of the third state,
The freeless energization pattern is a fourth state in which the switching element is PWM-controlled by a PWM signal having a maximum duty ratio larger than that in the PWM control in the third state, or a state in which the switching element is in the third state. A fifth state in which PWM control is performed by a PWM signal with a minimum duty ratio smaller than the PWM control of , or PWM control is performed by a PWM signal with an intermediate duty ratio between the maximum duty ratio and the minimum duty ratio Including an energization pattern that is any combination of the sixth state that is a state,
The brushless motor according to claim 1. The rectangular wave energization pattern is a first state in which the switching element is continuously turned on, a second state in which the switching element is continuously turned off, or a PWM-controlled state. Including an energization pattern that is any combination of the third state,
The freeless energization pattern is a seventh state in which the switching element is continuously turned on, or an eighth state in which the switching element is PWM-controlled by a PWM signal having a designated duty ratio input from the outside. state, or a 9th state that is a state PWM-controlled by a PWM signal with a duty ratio of 1/2 of the indicated duty ratio,
The brushless motor according to claim 1. The control unit
The energization pattern when the load integrated value becomes less than a predetermined second threshold smaller than the predetermined first threshold after the load integrated value becomes equal to or greater than the predetermined first threshold. to the freeless energization pattern,
The brushless motor according to any one of claims 1 to 3. The load integrated value is the power supply voltage supplied to the inverter, the rotational speed of the rotor, and the duty of the PWM signal under PWM control among the energized states constituting the freeless energized pattern or the rectangular wave energized pattern. A ratio is detected at predetermined intervals, and a value obtained by accumulating load point values calculated based on the detected three values,
The brushless motor according to any one of claims 1 to 4. a stator having three-phase windings;
a rotor having a permanent magnet and rotating facing the stator;
an inverter that has a plurality of switching elements and that turns on or off the plurality of switching elements to pass an alternating current through the three-phase winding;
The ON/OFF states of the plurality of switching elements are controlled by switching an energization pattern representing a change in the energization state of each phase of the three-phase windings according to the rotation of the rotor to a freeless energization pattern or a rectangular wave energization pattern. a control unit that
A control method for a brushless motor comprising
The control unit
When the load integrated value determined according to the load of the rotor is less than a predetermined first threshold, the energization pattern is switched to the freeless energization pattern, and the load integrated value is equal to or greater than the predetermined first threshold. switching the energization pattern to the rectangular wave energization pattern when
Control method of brushless motor. a brushless motor according to claim 6;
a wiper arm oscillated by the brushless motor;
a wiper blade connected to the wiper arm for reciprocally wiping a wiping area of the vehicle;
A control method for a wiper device comprising
The control unit switches the energization pattern when the position of the wiper blade is at the reverse position in the wiping area.
A wiper device control method. A control method for a wiper device according to claim 7,
Further, the control unit counts the number of wiping times of the wiper blade in the rectangular wave energization pattern, and switches from the rectangular wave energization pattern to the freeless energization pattern when the wiping count is equal to or greater than a predetermined value.
A wiper device control method.

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