TWI493862B - Device for controlling three-phase brushless motor - Google Patents

Description

Three-phase brushless motor control device

The present invention relates to a control device for a three-phase brushless motor, and more particularly to a control device for a three-phase brushless motor that maximizes the advantages of a 180-degree energization mode.

Further, the present invention relates to a control device for a three-phase brushless motor that maximizes the advantages of the 180-degree energization mode in the auxiliary control of the electric assist bicycle.

As a control method of the three-phase brushless motor, there is generally a 120-degree energization mode and a 180-degree energization drive mode (sine wave drive). 120-degree power-on mode, although the control is simple, and the general-purpose IC also appears in the strengths of most markets, but the 120-degree power-on mode is easier to generate noise or vibration than the 180-power mode, and is inferior to 180-degree power in efficiency. The problem with the way. On the other hand, in the 180-degree energization method, although the efficiency is better than the 120-degree energization method, and the quietness and vibration characteristics are excellent, there is a case where the transient load variation is poor, and when the positional shift occurs, Control, and control the complex shortcomings compared to the 120-degree power-on mode.

Although the 120-degree energization method and the 180-degree energization method are controlled by detecting the phase of the rotor by a sensor such as a Hall IC attached to the motor, in the 180-degree energization mode, the magnetic pole is predicted every 60 degrees. Since the position is shifted due to a transient load fluctuation or the like during motor rotation, the magnetic pole position cannot be predicted, and there is a possibility that the operation must be stopped. On the other hand, in the 120-degree energization method, since the phase current switching control is performed based on the rotor position detected by the sensor, and the prediction control is not performed, even if the positional shift occurs, the sensing can be performed based on the sensing. The location information of the device continues to operate. Further, in the 180-degree energization method, since the torque margin is small and the positional deviation is likely to occur with respect to the instantaneous load fluctuation, it is necessary to increase the torque and it is difficult to obtain a reduction in size of the motor.

In the case of the 180-degree energization method and the 120-degree energization method, there are advantages and disadvantages. For example, in Patent Documents 1 and 2, there is a proposal to combine the energization methods to control the respective advantages.

Patent Document 1 describes a method in which a 180-degree energization driving means 10 and a 120-degree energization driving means 11 are provided, and a 180-degree energization driving means 10 and a 120-degree energization driving means 11 are switched as necessary to perform driving control of the synchronous motor 1. Control device for electric vehicles. In the control device, the magnetic pole position θenc is calculated based on the output pulse wave from the rotational pulse wave generating means 9, and the magnetic pole position is driven by 180 degrees according to the magnetic pole position θenc. However, the state in which the rotational pulse wave generating means 9 cannot be used is obtained. At this time, the magnetic pole position θ is calculated based on the phase voltage V1 to perform the 120-degree energization drive. In the control device described in Patent Document 1, although the number of motor rotations is switched from the 180-degree energization method to the 120-degree energization method, the positional deviation is increased during the 180-degree energization drive due to the load state, and the change is made. The possibility of being unable to control.

Patent Document 2 discloses that the intermittent energization drive unit (120-degree energization drive unit) 8 and the 180-degree energization drive unit 9 are provided, and the 180-degree energization drive is performed in the normal state, and the power supply voltage or the load torque is used. When the disturbance detects a disturbance, the control device of the synchronous motor that intermittently drives (for example, 120-degree energization drive) is executed. The control device is configured, for example, to detect a DC power supply voltage, a number of rotations of the synchronous motor, a load torque generated in the synchronous motor, and a phase difference between the motor current, the drive voltage, and the motor current. When it is a disturbance signal and the disturbance signal exceeds the threshold value, it is switched from the 180-degree energization drive to the intermittent energization drive. However, when the drive mode is switched before the positional shift occurs, and the drive mode is switched by comparing the disturbance signal with the threshold value, the control object is slow, but the control object is faster. It will become uncontrollable when the positional deviation occurs during the judgment of the presence or absence of the disturbance. Therefore, in the control method of Patent Document 2, when the sudden load fluctuation occurs in the transient state, the stop of the motor cannot be avoided. Moreover, in order to detect the phase difference between the driving voltage and the motor current, there is a need for a high-performance personal computer, and it is difficult to reduce the cost.

(Patent Document 1) Japanese Patent Laid-Open No. Hei 10-341594

(Patent Document 2) Japanese Patent Laid-Open Publication No. 2001-245487

It is an object of the present invention to provide a control device for a three-phase brushless motor that can more reliably prevent a motor from being stopped due to a transient load fluctuation.

It is an object of the present invention to provide a control device for a three-phase brushless motor that maximizes the advantages of a 180 degree energization mode.

One aspect of the present invention relates to a control device for a three-phase brushless motor The device has a three-phase bridge inverter circuit (15) for supplying a driving voltage to each phase (U, V, W) of the three-phase brushless motor (37); and a complementary intermittent energizing driving means (32) Applying a PWM signal having a conduction angle of less than 180 degrees to the transistors (UH, UL, VH, VL, WH, WL) of the inverter circuit (15), and by means of complementary intermittent energization driving The aforementioned three-phase brushless motor is driven. The complementary intermittent energization driving means (32) is to apply two different phases of the PWM signal to the lower phase of each phase and to pass the current through the two-phase coil, and one phase of the three phases. Applying a PWM signal having the same operation ratio to the upper and lower transistors and passing the energy stored in the coil of the one phase through one of the upper and lower transistors, thereby flowing a current at a full electrical angle in each phase. The aforementioned three-phase brushless motor is driven by complementary intermittent energization. The complementary intermittent energization driving method is, for example, a complementary 120-degree energization driving method.

The control device controls the three-phase brushless motor by a complementary intermittent energization driving method, for example, in at least one of a start-up state or a transient-load state.

Here, the transient load state refers to an overload state in which the load of the motor is rapidly increased, for example, an overload state.

According to the control of the three-phase brushless motor with the complementary intermittent energization driving method excellent in transient load correspondence, it is possible to reliably prevent the motor from being stopped due to transient load fluctuation. In other words, in the motor control according to the 180-degree energization drive mode, since it is the predictive control for the future, it is necessary to stop the motor when the positional shift occurs due to the transient load fluctuation, but it is driven by the complementary intermittent energization. In the motor control of the mode, since the control is performed based only on the information from the sensor, it is possible to prevent the motor from being stopped due to transient load fluctuations. Further, according to the complementary intermittent energization driving method, the operation of the motor excellent in quietness and vibration characteristics can be performed. Further, by the complementary intermittent energization driving method, the motor is prevented from being stopped due to the transient load fluctuation, so that it is not necessary to excessively increase the torque for the purpose of preventing the positional deviation, and the motor and its driving device can be realized. miniaturization.

In one aspect of the invention, the three-phase brushless motor is controlled by a complementary intermittent energization driving method in at least one of a start-up state or a transient load state of the three-phase brushless motor.

When the motor is controlled by the complementary intermittent energization driving method in the startup operation state, even if there is a transient load fluctuation when the motor is started, the stop of the motor can be surely avoided. Further, after the motor is surely started, for example, the normal operation is performed by the 180-degree energization driving method, whereby motor control excellent in quietness, vibration characteristics, and efficiency can be performed.

Further, when the motor is controlled by the complementary intermittent energization driving method in the transient load state, for example, when the motor is started by the 180-degree energization driving method and the transient load is changed, the switching is performed by the complementary intermittent energization driving method. The motor control, when the transient load state is released, will be restored to the 180-degree energized drive mode. Further, for example, when the motor is controlled by the 180-degree energization driving method during the normal operation after the start of the motor, and the transient load is changed, if the switching to the complementary intermittent energization mode is performed and the transient load state is released, the operation is restored. 180 degree power-on drive mode. In this case, it is possible to avoid the motor from being stopped due to the transient load fluctuation and to control the efficiency efficiently, and it is possible to suppress the unevenness of the rotation and improve the vibration characteristics and the quietness. Further, by the complementary intermittent energization driving method, the motor in the startup operation state or the transient load state is prevented from being stopped, whereby the motor and its drive device can be downsized.

In one aspect of the present invention, the system has a 180-degree energization driving means (33), applies a PWM signal having a conduction angle of 180 degrees to the inverter circuit (15), and drives the foregoing by a 180-degree energization driving method. a three-phase brushless motor (37); and a driving mode selecting means (31) for selecting a complementary intermittent energizing driving mode in the starting operation state of the three-phase brushless motor (37), and in the aforementioned three-phase brushless motor (37) When the operating state is changed to the normal operating state, the 180-degree energization driving method is selected.

In this case, the motor is reliably activated by the complementary intermittent energization driving method, and when the motor is in the normal operation state, the motor is controlled by the 180-degree energization driving method, and the motor having excellent quietness, vibration characteristics, and efficiency can be operated. .

In one aspect of the present invention, the system includes: an intermittent energization driving means (34) for applying a PWM signal having a conduction angle of less than 180 degrees to the inverter circuit (15), and driving in an intermittent energization driving manner. The three-phase brushless motor (37); the drive mode selection means (31) selects an intermittent energization drive mode when a transient load state of the three-phase brushless motor (37) is detected. The intermittent energization driving method is, for example, a 120-degree energization driving method.

In this case, when the transient load state is detected during the normal operation of the three-phase brushless motor, the motor is controlled by the intermittent energization drive method having excellent transient load correspondence, whereby the stop of the motor can be prevented. The intermittent energization drive method is more efficient than the complementary intermittent energization drive method. Therefore, even when the transient load state continues for a long period of time, the motor operation can be continued while suppressing the decrease in efficiency.

In one aspect of the present invention, the drive mode selection means (31) is restored to the time when the transient load state is detected and the intermittent energization drive mode is selected, and then the resetting of the transient load state is detected. 180 degree power-on drive mode.

In this case, when the transient load state is released, by switching the control from the intermittent energization drive mode to the 180-degree energization drive mode, the 180-degree energization drive method excellent in quietness, vibration characteristics, and efficiency can be utilized to the maximum limit. .

In one aspect of the invention, the driving mode selection means (31) is such that the rotation speed of the three-phase brushless motor (37) becomes a predetermined value or more, and the forward rotation of the three-phase brushless motor (37) When the number of rotations of the direction is continuously detected for a predetermined number of times or more, it is judged that the state has been shifted from the startup operation state to the normal operation state.

In one aspect of the invention, the driving mode selection means (31) determines that the three-phase brushless motor (37) is in a transient load state when the reverse rotation of the three-phase brushless motor (37) is detected. In this case, since the pulse edge of the reverse rotation of the display motor is detected once, it is judged that it is in the transient load state, so that the transient load state can be quickly detected and switched from the 180-degree energization driving mode. The intermittent energization drive mode can reliably prevent the stop of the motor.

In one aspect of the present invention, the three-phase brushless motor (37) is used for auxiliary control of a power-assisted bicycle; and the driving mode selection means (31) is used in the three-phase brushless motor (37). When the rotation speed becomes a predetermined value or more, and the number of rotations of the three-phase brushless motor (37) in the forward rotation direction is continuously detected a predetermined number of times or more, and the range of the pedaling force of the electric assist bicycle becomes a predetermined value or less, the transient load is judged. The status has been lifted.

In one aspect of the present invention, the three-phase brushless motor (37) is used for auxiliary control of a power-assisted bicycle; and the driving mode selection means (31) is used in the three-phase brushless motor (37). When the rotational speed becomes equal to or greater than a predetermined value and the vehicle speed of the electric assist bicycle becomes equal to or greater than a predetermined value, it is determined that the transient load state has been released.

An aspect of the present invention is a control device for a three-phase brushless motor, comprising: a three-phase bridge converter circuit (15) for supplying a driving voltage to each phase of the three-phase brushless motor (37) ( U, V, W); and a complementary 120-degree energization driving means (32), applying a PWM signal having a conduction angle of 120 degrees to the transistors of the aforementioned inverter circuit (15) (UH, UL, VH, VL, WH, WL), and the aforementioned three-phase brushless motor is driven by a complementary 120-degree energization drive. The complementary 120-degree energization driving means (32) applies a PWM signal having a different working ratio to the lower phase of each of the two phases of the three phases and transmits the current through the coil of the two phases, and the working ratio is the same The PWM signal is applied to the upper and lower transistors of one of the three phases and the energy stored in the coil of the one phase is transmitted through any one of the upper and lower transistors, whereby the full electrical angle can be used in each phase. The current is distributed, and the three-phase brushless motor is energized and driven by 120 degrees.

The control device for the three-phase brushless motor of the present invention is not limited to the complementary 120-degree energization driving method, and is also applicable to any complementary intermittent energization driving method that is driven at a conduction angle of less than 180 degrees.

The control device for the three-phase brushless motor of the present invention is applicable to a power assist unit of a power-assisted bicycle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]

Fig. 1 shows an outline of the electric assist bicycle 1. As shown in Fig. 1, the main skeleton portion of the electric assist bicycle 1 is constituted by a metal-controlled vehicle body frame 3 like a normal bicycle, and the vehicle body frame 3 has a well-known aspect. The front wheel 20, the rear wheel 22, the handlebar 16, the saddle 18, and the like are mounted.

Further, the drive shaft 4 is rotatably supported at the lower center portion of the body frame 13, and the pedals 8L and 8R are attached to the left and right end portions thereof via the pedal cranks 6L and 6R, respectively. The drive shaft 4 is transmitted through a one-way clutch (a component symbol 99 of a third figure to be described later) for transmitting only the rotation in the R direction corresponding to the forward direction of the vehicle body, and the sprocket 2 is attached to the drive shaft. A chain 12 that rotates in a ring shape is provided between the sprocket 2 and the rear-wheel power mechanism 10 provided at a central portion of the rear wheel 22.

In the electric assist bicycle 1, a electric assist unit 11 that generates auxiliary electric power is attached. The generated auxiliary electric power is transmitted to the drive wheels (rear wheels) 22 using a resultant force mechanism to be described later.

FIG. 2 is a schematic view showing a control system of the electric assist bicycle 1 housed in the electric assist unit 11. The control system of the electric assist bicycle 1 is provided with: a microcomputer 14 for collectively controlling the electronic processing of the entire bicycle; and an inverter circuit 15 for converting a DC voltage into a predetermined voltage waveform by a control signal from the microcomputer 14 It is supplied to the motor 37. In the inverter circuit 15, a battery 17 (outside of the electric assist unit 11) that supplies power to the electric motor 37 is connected. Further, the electric assist unit 11 houses a reduction gear or the like for reducing the rotational speed of the motor.

The electric motor 37 is, for example, a three-phase brushless motor. The electric motor 37 is provided with, for example, a plurality of Hall ICs 371 for detecting a magnetic pole position (rotor phase), a motor rotation speed, and the like. The Hall IC 371 outputs a pulse wave signal corresponding to a magnetic field generated by a permanent magnet provided in the electric motor 37. The Hall IC 371 is provided with, for example, three at equal intervals around the rotation axis of the electric motor 37. However, only one Hall IC 371 is shown in FIG. The microcomputer 14 detects the magnetic pole position, the motor rotation speed, the number of motor rotations, and the motor rotation direction based on the pulse wave signal from the Hall IC 371.

The inverter circuit 15 is a three-phase bridge converter, and is a three-phase bridge-like circuit in which the transistors UH, UL, VH, VL, WH, and WL of the six semiconductor switching elements are connected. These transistors are driven by a PWM signal supplied from the microcomputer 14, and the DC voltage supplied from the battery 17 is converted to generate a driving voltage, and supplied to each phase of the electric motor 37.

In the microcomputer 14, a magnetic field pulse wave signal for detecting a crank angle formed by the pedal crank 6R (6L) with respect to the vehicle body frame 3 is input from a rotation angle sensor (described later), and is used to detect a one-way direction. The Hall IC 162 (described later) in which the clutch is deformed inputs magnetic field signals 1, 2, and 3 for calculating the pedaling force. The means for generating such input signals will be described later. In addition, signals can be input to specify a motor-assisted mode (eg, normal mode, turbo mode, power saving mode, etc.). The microcomputer 14 (the drive mode selection unit 31 to be described later) calculates the traveling speed (vehicle speed), the crank angle, and the pedaling force from the input signals, and performs electronic processing for determining the assist ratio (assisted force/stepping force) according to a predetermined algorithm. Next, the microcomputer 14 sequentially outputs a PWM command corresponding to the assisting force in order to command the electric motor 37 to generate an assisting force corresponding to the determined assist ratio. The details of the motor control performed by the microcomputer 14 according to the present embodiment will be described later.

Hereinafter, the pedaling force detecting mechanism, the resultant force mechanism, and the crank angle and the vehicle speed detecting mechanism of the electric assist bicycle according to the embodiment of the present invention will be described.

(Treading force detection agency)

The pedal force detecting mechanism that outputs the magnetic field signals 1, 2, and 3 input to the microcomputer 14 will be described using Figs. 3 to 7. The pedaling force detecting mechanism detects a magnetic field that changes according to the deformation of the one-way clutch 99 corresponding to the pedaling force.

As shown in FIG. 3, the one-way clutch 99 is provided with a dowel portion 100 and a tooth portion 112.

As shown in Fig. 4(a), the positioning pin portion 100 has a substantially disk shape in which a positioning pin portion bore 106 for accommodating the drive shaft 4 is formed at the center portion, and is equiangular along its circumferential direction. Three rigid ratchet dowels 102 are disposed on the second engagement surface 110 side facing the tooth portion 112. In order to accommodate the ratchet positioning pins 102, respectively, the positioning pin portions 100 are formed with three recessed portions 170 in the circumferential direction as shown in Fig. 4(b). Further, the ratchet positioning pin 102 is rotated in a state in which the concave portion 170 accommodates the rotating shaft portion, and the ratchet positioning pin 102 changes the angle with respect to the second engaging surface 110 in accordance with the rotation.

When referring to FIG. 4(b) again, the positioning pin portion 100 is adjacent to each of the recessed portions 170, and a linear groove 171 capable of accommodating the spring bar 104 is formed, and both end portions of the three linear grooves 171 are formed. It extends to the outer peripheral edge of the positioning pin portion 100. As shown in Fig. 4(c), the spring bar 104 is formed by bending one end portion A into a substantially vertical shape and the other end portion B in a U shape. When the spring bar 104 is attached to the linear groove 171 of the positioning pin portion 100, as shown in Fig. 4(b), the B-shaped portion is clipped as long as the spring bar 104 is slid in the linear groove. The spring bar 104 can be easily attached to the positioning pin portion 100 by sandwiching the positioning pin portion 100. However, once this state is maintained, the spring bar 104 may be detached due to the pulling force from the B portion. Therefore, the A portion bent into the vertical direction is engaged with the side wall of the positioning pin portion to prevent the spring bar from falling off. .

When the spring bar 104 is attached to the linear groove 171 of the positioning pin portion 100, the ratchet positioning pin 102 has a predetermined angle with respect to the second engaging surface 110 in the longitudinal direction when there is no external force (Fig. 5) The way to balance the direction of 160). As shown in FIG. 5, when the ratchet positioning pin 102 is biased from the balance direction 160 toward the ascending direction a or the descending direction b, the spring bar 104 brings the ratchet positioning pin 102 in such a manner that the bias is returned to the balance direction 160. Slightly elastic.

In the inner wall of the locating pin portion bore 106, four first rotation preventing grooves 108 extending in the axial direction 5 are formed. The outer wall portion of the drive shaft 4 that is in contact with the inner wall of the locating pin bore 106 is also formed in four axial directions 5 so as to face the first rotation preventing groove 108. 2 rotation preventing groove 140. As shown in Fig. 6 (a), the first rotation preventing groove 108 and the second rotation preventing groove 140 facing the surface are formed with cylindrical grooves extending in the axial direction and are in the respective cylindrical grooves. In the middle, a plurality of steel balls 150 are accommodated in such a manner as to be landfilled. Thereby, the positioning pin portion 100 is movable in the axial direction with a minimum coefficient of friction, and relative rotation of the drive shaft 4 can be prevented. Although it is a type of ball spline, it is also possible to apply other types of ball-bolt grooves, for example, a ball-shaped pin groove of a ring rotation, as such a slidable rotation preventing means.

Further, as a method of attaching the positioning pin portion 100 to the drive shaft 4, means other than the ball stud groove of Fig. 6(a) may be employed. For example, as shown in FIG. 6(b), the protrusion 140a extending in the axial direction is provided on the drive shaft 4, and the third rotation preventing groove 108a accommodating the protrusion 140 is formed in the positioning pin portion 100. The key spline form can also be applied as a means of preventing rotation. Further, in FIG. 6(b), the protruding portion 140a may be provided on the side of the positioning pin portion 100, and the third rotation preventing groove 108a may be provided on the side of the drive shaft 4. Further, as shown in FIG. 6(c), the fourth rotation preventing groove 108b extending in the axial direction and the fifth rotation preventing groove 140b facing the opposite surface are provided on the positioning pin portion 100 and the drive shaft 4, respectively. The so-called keyway form in which the key plates are accommodated in the rectangular parallelepiped grooves formed by the grooves can also be applied as a rotation preventing means.

As shown in FIG. 3, the disc spring 137 is interposed between the positioning pin portion 100 and the support disc 151 fixed to the drive shaft 4. Both ends of the disc spring 137 abut against the back surface of the positioning pin portion 100 and the support disc 151, respectively. Therefore, the disc spring 137 is elastically opposed to the inner side in the axial direction of the positioning pin portion 100.

On the other hand, as shown in FIG. 7, the tooth portion 112 is formed on the first engagement surface 121 which is the surface of the power transmission gear 200. The tooth portion 112 has a plurality of ratchet teeth 114 for engaging with the ratchet positioning pin 102. As shown in Fig. 5, the ratchet teeth 114 are formed by a steeply inclined inclination 118 with respect to the first engagement surface 121 and a gentle slope 116 formed periodically along the circumferential direction of the tooth portion. The tooth portion 112 is in a state in which the first engagement surface 121 faces the second engagement surface 110 of the positioning pin portion 100 and the ratchet positioning pin 102 is engaged with the ratchet teeth 114 (Fig. 5). The drive shaft 4 is pivoted in a slidable manner. That is, the drive shaft 4 can be operatively coupled to the tooth portion 112 by passing the engagement portion between the ratchet positioning pin 102 and the ratchet tooth 114.

As shown in Fig. 3, the power transmission device 200 including the tooth portion 112 is coaxially fixed to the sprocket 2 by using the fixing pin 206, and a pedal shaft is attached to the front end of the drive shaft 4. Further, a one-way clutch (ratchet gear) 99 that connects the drive shaft 4 and the sprocket 2 is completed in such a manner that only the rotation of the pedaling force in the forward direction of the vehicle body is transmitted to the sprocket 2.

Further, in the positioning pin portion 100 of the ratchet device 99, a permanent magnet 161 which is concentric with the drive shaft 4 and the positioning pin portion 100 and which is formed in a ring shape is attached. The ring-shaped permanent magnet 161 is preferably configured such that one surface of the ring is N pole and the other surface is S pole, and the ring axis direction of the permanent magnet 161 is aligned with the axis direction of the ratchet device 99. Arrange the arrangement in a tiered manner.

Further, a plurality of (three in the present embodiment) Hall ICs 162 for detecting a magnetic field are disposed at predetermined positions at three positions in a plane perpendicular to the axis of the drive shaft 4. Preferably, the predetermined positions of the three places of the Hall IC are arranged such that the axis is substantially equidistant in the radial direction and substantially equiangular in the circumferential direction. Further, the predetermined position at which the Hall IC 162 is disposed corresponds to a fixed position of the vehicle body frame 3 that is close to the annular permanent magnet 161. These Hall ICs 162 are connected to the microcomputer 14 (Fig. 2). The magnetic field signals (magnetic field detection signals) 1, 2, and 3 that are individually output from the three Hall ICs 162 are input to the microcomputer 14 (Fig. 2) as described above.

As an alternative embodiment, a ring member 163 made of a magnetic material such as iron may be used instead of the annular permanent magnet 161. In this case, the magnet 164 is fixed at a position close to the Hall IC 162 on the positioning pin portion 100. Further, the material of the ring member 163 may be made of any material capable of changing the magnetic field of the magnet 164, for example, a diamagnetic material.

When the rider provides the pedaling effort to the pedals 8R, 8L (Fig. 1) and rotates the drive shaft 4 in the vehicle body forward direction, the rotational force can be transmitted to a manner that is non-rotatable and slidable with respect to the drive shaft 4 The locating pin portion 100 of the shaft. At this time, as shown in FIG. 5, since the ratchet positioning pin 102 is supplied with the force Fd corresponding to the pedaling effort from the positioning pin portion 100, the tip end portion abuts against the steeper slope of the ratchet teeth of the tooth portion 112. 118, and this force is transmitted to the ratchet teeth. Since the ratchet tooth portion 112 is coupled to the sprocket 2, the front end portion of the ratchet positioning pin 102 receives the force Fp generated by the driving load from the steep slope 118. The ratchet positioning pin 102 that supplies the forces Fp and Fd in the opposite directions from both end portions is rotated in the a direction to stand up. At this time, the positioning pin portion 100 is moved inward in the axial direction by the rising of the ratchet positioning pin 102, and the disc spring 137 which is interposed between the positioning pin portion 100 and the support disk 151 is press-fitted. The disc spring 137 resists and acts on the positioning pin portion 100 with the elastic force Fr. The force Fr and the force reflecting the pedaling force for moving the positioning pin portion 100 in the axial direction are balanced in a short time. In this manner, the position of the positioning pin portion 100 in the axial direction becomes a physical quantity reflecting the pedaling effort.

In the case of the embodiment in which the annular permanent magnet 161 is used, the strength of the magnetic field detected by the Hall IC 162 differs depending on the position of the positioning pin portion 100 in the axial direction. That is, when the pedaling effort is increased, since the positioning pin portion 100 slides inward in the axial direction and the permanent magnet 161 approaches the Hall IC 162, the strength of the magnetic field detected by the Hall IC 162 increases. On the other hand, when the pedaling effort is reduced, since the positioning pin portion 100 slides outward in the axial direction and the permanent magnet 161 is away from the Hall IC 162, the strength of the magnetic field detected by the Hall IC 162 is reduced.

The pedaling force range detecting unit 40 (see FIG. 2) of the microcomputer 14 performs average calculation (including simple addition) of the magnetic field signals 1, 2, and 3 detected by the three Hall ICs 162 to obtain an average magnetic field strength. And the range of the pedaling force is obtained from the average magnetic field strength. In the present embodiment, the value of the magnetic field strength is divided into a plurality of ranges (the pedaling force range) in advance, and the assist ratio is also set in accordance with the pedaling force range. In other words, the assist ratio is set according to the range of the pedaling force to which the magnetic field strength belongs.

Since the magnetic field in the axial direction of the plurality of points is averaged in this way, not only the SN ratio can be improved, but also the pedal can be more accurately obtained by offsetting the unevenness of the magnetic field strength caused by the vibration of the positioning pin portion 100. The pedaling force T (the range of the pedaling force).

Further, in the case of an alternative embodiment using the magnetic member or the diamagnetic ring member 163, the magnetic field distribution of the magnet 164 changes depending on the influence of the magnetic body or the diamagnetic body in accordance with the axial position of the ring member 163. Therefore, even in the alternative embodiment, the pedaling effort T (the pedaling force range) can be obtained as described above based on the detected magnetic field strength.

In the above, the Hall IC 162 detects the displacement of the positioning pin portion 100 (the one-way clutch 99) in the axial direction, thereby detecting the pedaling force. However, the disc spring 137 may be configured to distorte the variable device by detecting The disc spring 137 is distorted, and the axial displacement of the positioning pin portion 100 (one-way clutch 99) and even the pedaling force (the pedaling force range) are detected. In this case, the value of the distortion variable is divided into a plurality of ranges (the pedaling force range) in advance, and the assist ratio is set in accordance with the pedaling force range.

(Joint organization)

Fig. 3 shows the power transmission device 200 coaxially fixed to the sprocket 2 using the fixing pin 206 as described above. As shown in Fig. 7, the power transmission device 200 has a plurality of teeth 204 formed on the outer peripheral portion.

As shown in Fig. 3, the teeth 204 of the power transmission device 200 are fitted to the gear 220 provided at the front end of the auxiliary force output shaft 222 of the electric assist unit 11. Therefore, the assisting force output from the electric assist unit 11 is transmitted to the power transmission device 200 through the shaft 222 and the gear 220, and is transmitted from the power transmitting device 200 to the drive wheel (rear wheel) 22 through the sprocket 2 and the chain 12. In this way, the combined force of the pedaling force and the assisting force can be achieved. Since the number of teeth 204 of the power transmission device 200 is larger than the number of teeth of the gear 220, the power transmission device 200 also functions as a reduction gear. Further, the assist force output shaft 222 is driven by the above-described electric motor 37 (second drawing).

(Crank angle and speed detection mechanism)

The crank angle detecting mechanism of the power-assisted bicycle 1 will be described using Figs. 3 and 7.

As shown in Fig. 7, on the plate surface side of one of the power transmission devices 200, twelve permanent magnets 202 are arranged in a circumference of 12 equal parts. The permanent magnets 202 expose one magnetic pole (N pole or S pole) on the surface of the board surface, and the other magnetic pole faces the side opposite to the surface, and the direction connecting the two magnetic poles is neatly arranged. It is arranged in the axial direction of the drive shaft 4. The magnetic poles exposed on the surface of the plate surface are preferably aligned in the same manner, but the magnetic poles of the adjacent magnets 202 may be arranged in a staggered manner.

When referring to FIG. 3, the Hall IC 210 is disposed adjacent to the board surface of the power transmission device 200 on which the permanent magnet 202 is disposed, and is fixed to the vehicle body frame 3. The radial distance of the Hall IC 210 from the drive shaft 4 is set to be substantially the same as the radial distance of the permanent magnet 202 from the drive shaft 4. The permanent magnet 202 and the Hall IC 210 constitute a crank rotation angle sensor. Since the power transmission device 200 rotates together with the rotation of the pedal, and the Hall IC 210 is stationary with respect to the vehicle body, the magnetic field of the permanent magnet 202 is successively transected to the Hall IC 210 by the rotation of the pedal crank. examination range. Therefore, the Hall IC 210 outputs a detection signal corresponding to the number of pulses of the pedal crank rotation number. The magnetic field pulse signal is input to the vehicle speed detecting unit 41 of the microcomputer 14 (Fig. 2).

Since the power transmission device 200 rotates together with the pedal crank and the sprocket 2, the rotational speed of the power transmission device 200 reflects the vehicle speed and the crank angular velocity. In this manner, the vehicle speed detecting unit 41 can calculate the vehicle speed and the crank angle from the number of times of the magnetic field pulse wave signal per unit time.

(motor control unit)

Next, a control device for causing the electric motor 37 that generates the auxiliary electric power of the electric assist unit 11 will be described with reference to Fig. 2 and Figs. 8 to 14.

The motor control device of Fig. 2 includes an inverter circuit 15 that supplies a driving voltage to the three-phase brushless electric motor 37 as described above, a microcomputer 14 and three Hall ICs 371 (only FIG. 2) Show 1). The three Hall ICs 371 are arranged at equal intervals of 120 degrees in the electric motor 37, and output pulse signals as shown in the upper diagrams of Figs. 8, 9, and 11 in accordance with the detected magnetic field strength. Hu, Hv, Hw.

Hereinafter, for convenience of explanation, the transistors of the inverter circuit 15 connected to the U, V, and W phases of the electric motor 37 may be referred to as a U-phase transistor, a V-phase transistor, and a W-phase, respectively. The transistor is referred to as a lower electrode in the transistor of each phase, and a lower transistor in the lower potential side.

In the microcomputer 14, the transient load state detecting unit 36 receives the pulse wave signals Hu, Hv, and Hw output from the three Hall ICs 371, and normally monitors whether or not the pulse signals Hu, Hv, and Hw are rotated with the motor. The pulse signal patterns in the forward direction (CW direction) are the same. The transient load state detecting unit 36 detects a pulse wave in which the motor rotation in the reverse direction (CCW direction) is detected when the received pulse wave signals Hu, Hv, and Hw are different from the forward pulse wave signal pattern. At the edge, it is determined that the electric motor 37 is in a hunting operation state (transient load operation state), and a transient load state detection signal is output.

Table 1 is a truth table of pulse wave signals Hu, Hv, and Hw output from the Hall IC 371.

As shown in Table 1, when the magnetic pole position is currently in the range of 0-60 degrees, and the pulse signal is detected by the Hall IC 371, Hu, Hv, Hw = 0, 1, 0, the next 60 The signal mode to be ranged from -120 degrees is Hu, Hv, Hw = 0, 1, 1. Therefore, the microcomputer 14 is next to Hu, Hv, Hw=0, 1, 0, and immediately receives a signal mode other than Hu, Hv, Hw=0, 1, 1, and immediately determines the reversal or positional deviation of the motor. shift.

The motor rotation speed detecting unit 38 counts the number of switching of the mode of the pulse wave signal output from the Hall IC 371 (the number of pulse wave edges), and calculates the number of rotations of the electric motor 37 per minute (motor rotation speed rpm).

The motor rotation number detecting unit 39 monitors a change in the mode of the pulse wave signal output from the three Hall ICs 371, and detects that the motor rotation is forward or reverse (detecting the forward or reverse pulse wave edge), and counting the pulse wave The number of times the signal mode is switched, thereby calculating the number of rotations of the motor in the forward and reverse directions.

The pedaling force range detecting unit 40 (see FIG. 2) performs average calculation (including simple addition calculation) on the magnetic field signals 1, 2, and 3 detected by the three Hall ICs 162 as described above to obtain an average magnetic field strength. And by referring to a look-up table, the range of the pedaling force is obtained from the average magnetic field strength. Further, the assist ratio obtained by the auxiliary unit 11 is determined in consideration of the stepping force range, but the average value of the magnetic field signals 1, 2, and 3 corresponding to the pedaling force T is a stepping force range (the pedaling force range = 0) that is less than a predetermined value. The internal parameters indicate no load, and within the range of the pedaling force, the auxiliary force (auxiliary ratio 0) is not generated.

The vehicle speed detecting unit 41 receives a detection signal (magnetic field pulse wave signal) of the pulse wave number corresponding to the number of pedal crank rotations output from the Hall IC 210, and calculates the vehicle speed from the number of times of the magnetic field pulse wave signal per unit time. Crank angle.

The energization drive mode selection unit 31 selects the 180-degree energization drive mode, the 120-degree energization drive mode, and the complementary 120-degree energization according to the motor rotation speed, the motor rotation number, the motor rotation direction, the pedal force range, the vehicle speed, and the transient load state detection signal. One of the driving modes, and outputs a selection signal of the energization driving mode. Specifically, the energization drive mode selection unit 31 outputs a complementary 120-degree energization drive selection signal when the electric motor 37 is started (startup operation state), and outputs 180-degree energization during normal operation (normal operation state) of the electric motor 37. The selection signal is driven, and when the electric motor 37 is in the transient load operation state (unstable operation state), the 120-degree energization drive signal is output.

The detection of each operation state is as follows as an example. It is determined that the "motor rotation speed is 50 rpm or more" and the "continuous detection of the number of motor rotations of the forward direction of 60 times" is determined as the startup operation state, and when both conditions are satisfied, it is determined that the operation state has become the normal operation state.

Further, after the normal operation state is detected, when "the number of reverse motor rotations is also detected once", it is determined that the operation is in an unstable operation state (transient load operation state).

In addition, when the three conditions of "motor rotation speed is 126 rpm or more" and "continuous detection of 240 times of motor rotation in the forward direction" and "the pedaling force range is 0 (the internal parameter indicates no load)" are satisfied, it is judged that The unstable operation state (transient load operation state) is changed to the normal operation state. Here, although "the pedaling force range is 0" is regarded as one condition, it is also possible to set "the pedaling force range is equal to or less than a predetermined value". In addition, the detection of the release of the unstable operation state (transient load operation state) may be determined when the two conditions of "motor rotation speed is 126 rpm or more" and "vehicle speed (internal speed) is 6 km/h or more" are satisfied. It has changed from the unstable operation state (transient load operation state) to the normal operation state.

The 180-degree energization drive unit 33 calculates the magnetic pole position based on the pulse wave signals received from the three Hall ICs 371 provided in the electric motor 37, and based on the calculated magnetic pole position, the drive current waveform pair shown in FIG. The electric motor 37 is electrically driven at 180 degrees. Specifically, when receiving the 180-degree energization drive selection signal from the energization drive mode selection unit 31, the 180-degree energization drive unit 33 determines the assist ratio according to a predetermined algorithm based on the vehicle speed, the crank angle, and the pedal effort range (auxiliary Electronic processing of force/force. Further, since the 180-degree energization drive unit 33 drives the electric motor 37 by 180 degrees so as to generate an assist force corresponding to the determined assist ratio, the magnetic pole is predicted based on the detected value detected by the Hall IC 371. The position is set and the power-on sequence is set, and the duty ratio of the PWM signal is set in accordance with the auxiliary ratio.

The 120-degree energization drive unit 34 calculates the magnetic pole position based on the pulse wave signals received from the three Hall ICs 371 provided in the electric motor 37, and based on the calculated magnetic pole position, the drive current waveform pair shown in FIG. The electric motor 37 is electrically driven at 120 degrees. Specifically, when receiving the 120-degree energization drive selection signal from the energization drive mode selection unit 31, the 120-degree energization drive unit 34 determines the assist ratio according to a predetermined algorithm based on the vehicle speed, the crank angle, and the pedal effort range (auxiliary Electronic processing of force/force. Further, since the 120-degree energization drive unit 34 energizes the electric motor 37 by 120 degrees so as to generate an assist force corresponding to the determined assist ratio, the energization is set based on the magnetic pole position detected by the Hall IC 371. Timing, and setting of the duty ratio of the PWM signal according to the auxiliary ratio.

The complementary 120-degree energization drive unit 32 calculates the magnetic pole position based on the pulse wave signal received from the three Hall ICs 371 provided in the electric motor 37, and uses the drive current waveform shown in FIG. 11 based on the calculated magnetic pole position. The electric motor 37 is energized and driven by a complementary 120 degrees. Specifically, when the complementary 120-degree energization drive unit 32 receives the complementary 120-degree energization drive selection signal from the energization drive mode selection unit 31, the auxiliary ratio is determined according to a predetermined algorithm based on the vehicle speed, the crank angle, and the pedal effort range. Electronic processing of (assisted force / pedaling force). Further, since the 120-degree energization drive unit 32 is electrically driven by the electric motor 37 in a complementary manner by generating an assist force corresponding to the determined assist ratio, the magnetic pole position detected by the Hall IC 371 is used. The energization timing is set and the duty ratio of the PWM signal is set.

The PWM generating unit 35 is configured to drive for each transistor based on the energization timing and the duty ratio set by the 180-degree energization drive unit 33, the 120-degree energization drive unit 34, and the complementary 120-degree energization drive unit 32. The PWM signals of the transistors (UH, UL, VH, VL, WH, WL) of the inverter circuit 15 are output.

The inverter circuit 15 switches each transistor in accordance with a PWM signal for 180-degree energization driving, 120-degree energization driving, or complementary 120-degree energization driving output from the microcomputer 14, and applies a driving voltage (driving current) to the electric motor. 37 phases.

Hereinafter, a description will be given while comparing the complementary 120-degree energization driving method and the 120-degree energization driving method.

[120 degree power drive mode] Fig. 9 is a view showing a current waveform (vertical axis) of each phase of the motor with respect to the energization angle (horizontal axis) in the 120-degree driving mode. Fig. 10 is a view for explaining a duty ratio of a PWM signal applied to each transistor in a 120-degree energization driving method and a path of a current flowing to each phase of the motor. In these figures, <1> indicates a state in which the electrical angle is 0 to 60 degrees; <2> indicates a state in which the electrical angle is 60 to 120 degrees; and <3> indicates a state in which the electrical angle is 120 to 180 degrees; <4 > indicates a state in which the electrical angle is 180 to 240 degrees; <5> indicates a state in which the electrical angle is 240 to 300 degrees; and <6> indicates a state in which the electrical angle is 300 to 360 degrees. In Fig. 10, the interval <1> is that the transistor VL is applied with a PWM signal of, for example, a duty ratio of 25% under the U-phase and the V-phase of the U-phase, and a duty ratio of 0% is applied to other transistors. The PWM signal is turned off. At this time, the current output from the battery 17 flows into the U-phase coil of the electric motor 37 through the U-phase upper transistor UH, and flows out from the V-phase coil and returns to the V-phase lower transistor VL to return to Battery 17. At this time, no current flows through the coil of the W phase. The interval <2> is that the transistor WL of the U phase and the W phase is applied with a PWM signal having a duty ratio of 25%, and the other transistor is turned off by applying a PWM signal with a duty ratio of 0%. At this time, the current output from the battery 17 flows into the U-phase coil of the electric motor 37 through the U-phase upper transistor UH, and flows out from the W-phase coil and returns to the W-phase lower transistor WL to return to Battery 17. At this time, no current flows through the coil of the V phase. In the interval <3>, the transistor WL is applied with a PWM signal having a duty ratio of 25% below the V phase and the W phase, and the other transistor is turned off by applying a PWM signal having a duty ratio of 0%. At this time, the current output from the battery 17 flows into the coil of the V phase of the electric motor 37 through the V-phase upper transistor VH, and flows out from the coil of the W phase and returns through the transistor WL under the W phase. To battery 17. At this time, no current flows through the coil of the U phase. The interval <4> is that the transistor UL is applied with a PWM signal having a duty ratio of 25% below the V phase of the transistor VH and the U phase, and is turned off when the other transistor is applied with a PWM signal having a duty ratio of 0%. At this time, the current output from the battery 17 flows into the coil of the V phase of the electric motor 37 through the V-phase upper transistor VH, and flows out from the coil of the U phase and returns to the transistor UL through the U phase. Battery 17. At this time, no current flows through the coil of the W phase. The interval <5> is that the transistor UL is applied with a PWM signal having a duty ratio of 25% below the W phase and the U phase of the transistor, and the other transistor is turned off by applying a PWM signal having a duty ratio of 0%. At this time, the current output from the battery 17 flows into the W-phase coil of the electric motor 37 through the W-phase upper transistor WH, and the current flows from the U-phase coil and returns through the U-phase under the transistor UL. To battery 17. At this time, no current flows through the coil of the V phase. The interval <6> is that the transistor VL is applied with a PWM signal having a duty ratio of 25% below the W phase and the V phase of the transistor, and the other transistor is turned off by applying a PWM signal with a duty ratio of 0%. At this time, the current output from the battery 17 flows into the W-phase coil of the electric motor 37 through the W-phase upper transistor WH, and the current flows from the V-phase coil and returns to the V-phase lower transistor VL. To battery 17. At this time, no current flows through the coil of the U phase. Further, in the above description, the PWM signal having a duty ratio of 25% is applied to the on-state transistor, but the duty ratio can be changed in accordance with the assist ratio. It can be understood from Fig. 9 and Fig. 10 that in the 120-degree energization driving method, among the phases of U, V, and W, there is no circulation in the range of the electrical angle of 60 degrees between the energization sections of the electrical angle of 120 degrees. Current interval (non-energized interval). [Complementary 120 degree power drive]

As shown in Fig. 14, the complementary 120-degree energization drive mode is a power-driven drive mode that theoretically controls the duty ratio of the PWM signal of the 120-degree energization drive mode. As shown in Fig. 14, in the 120-degree energization driving method, although the PWM signals of 0% of the operation ratio are applied to the upper and lower transistors UH and UL which are not selected as the current paths, the complementary 120-degree energization is performed by the pair. The upper and lower transistors UH and UL each apply a PWM signal having a duty ratio of 50%, and the current flowing to the motor is set to zero. By using this principle, the transistor to be turned on can be determined according to the larger one of the upper and lower transistors UH and UL. For example, as shown in the middle of Fig. 14, if the operating ratio of the upper transistor UH is set to 75% and the operating ratio of the lower transistor UL is set to 25%, current flows from the upper transistor UH to the motor. On the other hand, if the operating ratio of the upper transistor UH is set to 25% and the operating ratio of the lower transistor UL is set to 75%, current flows from the motor to the lower transistor UL. In the complementary 120-degree energization driving method, this principle is utilized, and in the lower phase of the two-phase selected as the current path, the operating ratio of the upper and lower transistors is set to be higher than that of the other transistor. The ratio is larger, and in the phase not selected as the current path, the operating ratio of the upper and lower transistors is set to be the same.

Fig. 11 is a view showing a current waveform (vertical axis) of each phase of the motor with respect to the energization angle (horizontal axis) in the complementary 120-degree driving mode. Fig. 12 is a view for explaining a duty ratio of a PWM signal applied to each transistor in a complementary 120-degree energization driving method and a path of a current flowing to each phase of the motor. In the figures, the intervals <1> to <6> show the sections of the energization angles similar to those of the ninth and tenth diagrams. Here, although the specific work ratio is also exemplified, the duty ratio can be changed in accordance with the assist ratio.

In the complementary 120-degree energization drive method, as shown in the interval <1> in Fig. 12, the 2-phase U and V phases of the current path are selected by the 120-degree energization drive method (corresponding to the interval <1> of Fig. 10). By applying a PWM signal with a duty ratio of 75% to the transistors UH and VL and a PWM signal having a duty ratio of 25% to the transistors UL and VH, the transistor can be circulated via the transistors UH and VL in the same manner as the 120-degree energization driving method. Current (solid arrow). Further, a PWM signal having a duty ratio of 50% is applied to the lower transistors WH and WL above the W phase which is not selected as the current path to set the current theoretically flowing to the W phase to zero. However, in the complementary 120-degree energization driving method, in the W phase which is not selected as the current path, the energy stored in the W-phase coil of the motor is discharged at the timing when the transistor WL is turned on (dashed arrow). This is because before the interval <1> is entered, in the preceding interval <5> to <6>, the current flows into the W-phase coil of the electric motor 37 (solid arrow), and is changed in the W-phase coil. The side of the streamer circuit 15 is charged at a higher potential than the neutral point; the transmitted energy passes through the lower transistor WL from the W-phase coil at a timing after the lower transistor WL is turned on in the interval <1>. The current is drawn (dotted arrow) to the low potential side of the battery 17.

The same applies to the sections <2> to <6> except for the section <1>. In the section <2>, in the U phase and the W phase, a current flows in the same manner as the section <2> in the tenth diagram. On the other hand, although the lower duty transistors VH and VL are applied with the PWM signal of the same duty ratio (50%) above the V phase, they will be in the preceding interval <6>, <1> immediately before entering the interval <2>. The current flows from the V-phase coil of the motor, and the V-phase coil accumulates energy in a state where the neutral point side becomes higher than the inverter circuit 15 side. Therefore, in the interval <2>, when a PWM signal having a duty ratio of 50% is applied to the lower transistors VH and VL above the V phase, the upper transistor VH is turned on at the timing of applying the pulse wave to the upper transistor VH. And the current flows from the high potential side of the battery 17 to the V-phase coil (dashed arrow) via the upper transistor VH.

In the interval <3>, the V phase and the W phase are distributed, and the current flows in the same manner as the interval <3> in the tenth graph. Although the transistors UH and UL are applied with the PWM signal of the same duty ratio (50%) above the U phase, the current flows in the preceding intervals <1> and <2> just before entering the interval <3>. In the U-phase coil of the motor, the U-phase coil accumulates energy in a state where the converter circuit 15 side becomes higher than the neutral point side. Therefore, in the interval <3>, when a PWM signal having a duty ratio of 50% is applied to the lower transistor UH and UL above the U phase, the timing of the pulse wave is applied to the lower transistor UL to cause the lower transistor UL. Turning on, current flows from the U-phase coil to the low potential side of the battery 17 via the lower transistor UL (dashed arrow).

In the interval <4>, the U phase and the V phase are distributed, and the current flows in the same manner as the interval <4> in the tenth graph. Although the lower-voltage transistors WH and WL are applied with the PWM signal of the same duty ratio (50%) above the W phase, they will be in the preceding interval <2>, <3> from the motor before entering the interval <4>. The W-phase coil flows current, and the W-phase coil accumulates energy in a state where the neutral point side becomes higher than the inverter circuit 15 side. Therefore, in the interval <4>, when a PWM signal having a duty ratio of 50% is applied to the lower transistors WH and WL over the W phase, the timing of the pulse wave is applied to the upper transistor WH to cause the upper transistor WH. Turned on, and current flows from the high potential side of the battery 17 to the W-phase coil (dashed arrow) via the upper transistor WH.

In the interval <5>, in the U phase and the W phase, a current flows in the same manner as the interval <5> in the tenth graph. Although the lower duty transistors VH and VL are applied with the PWM signal of the same duty ratio (50%) above the V phase, the current flows in the preceding intervals <3> and <4> just before entering the interval <5>. In the V-phase coil of the motor, the V-phase coil accumulates energy in a state where the inverter circuit 15 side becomes higher than the neutral point side. Therefore, in the interval <5>, when a PWM signal having a duty ratio of 50% is applied to the lower transistors VH and VL above the V phase, the timing of the pulse wave is applied to the lower transistor VL to lower the transistor VL. Turned on, and current flows from the V-phase coil to the low potential side of the battery 17 via the lower transistor VL (dashed arrow).

In the interval <6>, the V phase and the W phase are distributed, and the current flows in the same manner as the interval <6> in the tenth graph. Although the transistor UH and UL are applied with the PWM signal of the same duty ratio (50%) above the U phase, before entering the interval <6>, the motor will be in the preceding interval <4>, <5>. The U-phase coil flows current, and the U-phase coil accumulates energy in a state where the neutral point side becomes higher than the inverter circuit 15 side. Therefore, in the interval <6>, when a PWM signal having a duty ratio of 50% is applied to the upper transistor UH, UL above the U phase, the timing of the pulse wave is applied to the upper transistor UH to make the upper transistor UH. Turning on, current flows from the high potential side of the battery 17 to the U-phase coil (dashed arrow) via the upper transistor UH.

As described above, in the complementary 120-degree energization drive, any phase of the U, V, and W phases flows through the entire range <1> to <6>, and there is no non-conduction interval in any of the phases. Therefore, as shown in Fig. 11, the current of each phase is continuously changed over the entire range of the electrical angle of 360 degrees, whereby the electrical shock at the time of phase switching which may occur in the 120-degree energization driving mode can be suppressed.

[Control flow]

Hereinafter, an example of motor control using the motor control device of the present embodiment will be described with reference to a flowchart of Fig. 13.

In step S11, the electric motor 37 is activated by energization driving at a complementary 120 degrees.

In step S12, it is determined whether or not the rotational speed of the electric motor 37 has become 50 rpm or more and whether the number of rotations of the electric motor 37 in the forward direction (CW direction) has been continuously detected 60 times. When the condition is not satisfied, the process proceeds to step S11, and the startup operation of the complementary 120-degree energization drive is continued.

When the condition of both of the steps S12 has been satisfied, the process proceeds to step S13, and the motor control of the 180-degree energization drive mode is switched.

In step S14, it is determined whether or not a transient load fluctuation has been detected. Specifically, it is determined whether or not "detecting the motor rotation in the reverse direction (CCW direction) once), and when the motor rotation in the reverse direction is not detected, the process proceeds to step S13, and the motor control of the 180-degree energization drive mode is continued.

On the other hand, when it is detected in step S14 that the reverse motor is rotated, the process proceeds to step S15, and is switched to the motor control of the 120-degree energization drive mode.

In step S16, it is determined whether or not the transient load state has been released. Specifically, when the "motor rotation speed is 126 rpm or more" and "continuous detection of 240 times of forward motor rotation" and "the pedaling force range is 0" are satisfied, the overload state is detected. In addition, when the "motor rotation speed is 126 rpm or more" and the "vehicle speed (internal speed) is 6 km/h or more" is satisfied, the release of the overload state can be detected.

When the release of the transient load state is not detected in step S16, the process proceeds to step S15, and the motor control of the 120-degree energization drive mode is continued.

On the other hand, when the release of the transient load state has been detected in step S16, the process proceeds to step S13, and the motor control of the 180-degree energization drive mode is restored.

[Comparison of power-on drive methods]

Table 2 shows the characteristics of each energization drive mode of the 180-degree energization drive mode, the 120-degree energization drive mode, and the complementary 120-degree energization drive mode. In the table, the double circle is displayed in the three power-on driving modes. This characteristic is particularly good. The single circle indicates that the characteristic is good, the triangle indicates that the performance is slightly poor, and the cross-mark indicates that the performance is poor. .

As shown in Table 2, the 180-degree power-on drive mode is excellent in quietness, vibration characteristics, and efficiency. On the other hand, in the 180-degree energization driving method, since the transient load correspondence is weak for the future predictive control, there is a possibility that it is uncontrollable when the positional shift occurs due to the transient load. In addition, the 180-degree energization drive method is more complicated than the 120-degree energization drive method.

The 120-degree energization drive method is excellent in transient load response characteristics because it is controlled only based on the magnetic pole position detected by the Hall IC of the motor and is not subjected to predictive control. Therefore, it is possible to continue the control even when the operation is performed in an overload state due to a sudden load fluctuation, and the stop of the motor can be avoided. Moreover, the control is simple and the efficiency is good. However, there are disadvantages that the vibration characteristics are slightly poor and the quietness is poor.

The complementary 120-degree energization drive mode is superior to the transient load corresponding characteristic because it is controlled only based on the magnetic pole position detected by the Hall IC of the motor and is not subjected to predictive control. The transient load corresponding characteristics are good. Therefore, it is possible to continue the control even when the operation is performed in an overload state due to a sudden load fluctuation, and the stop of the motor can be avoided. Moreover, the quietness and vibration characteristics are particularly excellent. On the other hand, there is a disadvantage that the control is complicated and the efficiency is the worst of the three methods.

In the above-described embodiment, when a motor that is in a transient load state and is required to have good quietness and vibration characteristics is started, the motor is controlled by a complementary 120-degree energization drive method, thereby generating a motor start-up operation. In the case of a transient load change, the motor can be surely stopped to continue the operation, and the start-up operation with less noise and vibration can be performed.

In the normal operation in which the rotational speed and the number of rotations of the motor reach a predetermined value, the motor control can be switched to the 180-degree energization drive mode, and comfortable operation with less noise and vibration can be performed, and efficiency can be improved to suppress power consumption. .

In addition, when a transient load fluctuation occurs during normal operation, the motor control can be switched to the 120-degree energization drive mode, and the operation can be continued while avoiding the stop of the motor while suppressing the decrease in efficiency.

Further, after switching to the 120-degree energization drive mode, when the transient load state is released, by returning to the 180-degree energization drive mode, the operation with excellent quietness, vibration characteristics, and efficiency can be utilized to the maximum.

As described above, according to the present embodiment, it is possible to reliably avoid the stop of the motor while suppressing noise and vibration by the complementary 120-degree energization driving method during the start-up operation of the motor, and it is possible to pass the 180 after the transition to the normal operation. The power-on driving method uses the operation with less noise and vibration and high efficiency to the maximum limit, and when a transient load fluctuation occurs, the motor can be surely avoided by the 120-degree energization drive method while suppressing the decrease in efficiency. stop.

[Other Embodiments]

Further, in the above-described embodiment, the control is switched to the 120-degree energization drive mode when the transient load state is detected after the transition to the normal operation. However, when the efficiency can be reduced, the process may be shifted to When the transient load state is detected after the normal operation, the switch is switched to the complementary 120-degree energization drive mode. In this case, even during the transient load operation, it is possible to perform an operation with less noise and vibration, and to make the operation of the electric assist bicycle more comfortable.

Further, in the above-described embodiment, the start-up operation of the motor is performed by the complementary 120-degree energization driving method. However, the motor can be started up by the 120-degree energization driving method while allowing noise and vibration. In this case, the efficiency at the time of starting the motor can be improved.

Further, it is also possible to configure a motor start control that continues to complement the 120-degree energization drive mode (or the 120-degree energization drive mode) until the motor is in the normal operation state, and activates the motor by the 180-degree energization drive method, and detects the transient state. In the load state, the mode is switched to the complementary 120-degree energization drive mode (or the 120-degree energization drive mode), and when the transient load state is detected, the 180-degree energization drive mode is restored.

Further, in the above-described embodiment, the 120-degree energization drive method and the complementary 120-degree energization drive method have been exemplified, but the present invention can be applied to other intermittent energization drive that intermittently energizes at a conduction angle of less than 180 degrees and 120 degrees. Mode and complementary intermittent energization mode.

1. . . Electric assisted bicycle

2. . . Sprocket

3. . . Body frame

4. . . Drive shaft

5. . . Axis direction

6L, 6R. . . Pedal crank

8. . . Intermittent energization drive unit (120-degree energization drive unit)

8L, 8R. . . pedal

9. . . Rotary pulse wave generation means (180 degree energization drive unit)

10. . . Rear wheel power mechanism

11. . . Electric auxiliary unit

12. . . Chain

13. . . Body frame

14. . . Microcomputer

15. . . Inverter circuit

16. . . Handle

17. . . battery

18. . . Seat

20. . . Front wheel

twenty two. . . rear wheel

31. . . Drive mode selection unit

32. . . Complementary 120 degree power drive unit

33. . . 180 degree power drive unit

34. . . 120 degree power drive unit

35. . . PWM Production Department

36. . . Transient load status detection unit

37. . . electric motor

38. . . Motor rotation speed detecting unit

39. . . Motor rotation number detecting unit

40. . . Step force detection unit

41. . . Vehicle speed detection department

99. . . One-way clutch (ratchet device)

100. . . Locating pin

102. . . Ratchet positioning pin

104. . . Spring rod

106. . . Locating pin boring

108. . . First rotation preventing groove

108a. . . Third rotation preventing groove

108b. . . Fourth rotation preventing groove

110. . . 2nd engagement surface

112. . . Tooth

114. . . Ratchet tooth

116. . . Bevel

118. . . Tilt (bevel)

121. . . First engaging surface

137. . . Disc spring

140. . . Second rotation preventing groove

140a. . . Protrusion

140b. . . Fifth rotation preventing groove

150. . . Steel ball

151. . . Support disc

160. . . Balance direction

161, 202. . . permanent magnet

162, 210, 371. . . Hall IC

163. . . Ring member

164. . . magnet

170. . . Concave

171. . . Straight groove

200. . . Power transmission device

204. . . tooth

206. . . Fixed pin

220. . . gear

222. . . Auxiliary output shaft

a. . . Rising direction

b. . . Down direction

Fd, Fp. . . force

Fr. . . elastic force

Hu, Hv, Hw. . . Pulse signal

T. . . Pedal force

Fig. 1 is a schematic view showing a power-assisted bicycle according to an embodiment of the present invention.

Fig. 2 is a schematic view showing a control system of the electric assist bicycle shown in Fig. 1.

Fig. 3 is a side view of a one-way clutch in which a torque detecting mechanism according to an embodiment of the present invention is incorporated, which is used in the electric assist bicycle shown in Fig. 1.

Figure 4 is a schematic view showing the configuration of the locating pin portion of the one-way clutch and the spring bar used in the locating pin portion; wherein (a) is a perspective view of the locating pin portion in a state in which the spring bar is attached; (b) is removed A perspective view of the positioning pin portion in the state behind the spring bar; (c) is a side view of the spring bar.

Fig. 5 is a schematic view showing the fitting state of the teeth and the positioning pin of the one-way clutch (ratchet device) for explaining the principle of the pedaling force detection of the electric assist bicycle shown in Fig. 1.

Fig. 6 is a view showing an example of a rotation preventing means for preventing relative rotation of the positioning pin portion with respect to the drive shaft; wherein (a) shows a ball pin groove, (b) shows a pin groove key, and (c) shows a key groove. A top view of the schematic structure.

Fig. 7 is a front view and a side view of a power transmission device used in the resultant mechanism of the embodiment of the present invention.

Fig. 8 is a current waveform diagram of each phase in the 180-degree energization driving method.

Fig. 9 is a current waveform diagram of each phase in the 120-degree energization driving method.

Fig. 10 is a schematic diagram showing the duty ratio and current path of the PWM signal in the 120-degree energization driving mode.

Figure 11 is a current waveform diagram of each phase in a complementary 120-degree energization drive mode.

Fig. 12 is a view showing the duty ratio and current path of the PWM signal in the complementary 120-degree energization driving mode.

Figure 13 is a flow chart showing the control flow of the motor control device according to an embodiment of the present invention.

Fig. 14 is a view showing the control interchange of the 120-degree energization drive mode and the complementary 120-degree energization drive mode.

14. . . Microcomputer

15. . . Inverter circuit

17. . . battery

31. . . Drive mode selection unit

32. . . Complementary 120 degree power drive unit

33. . . 180 degree power drive unit

34. . . 120 degree power drive unit

35. . . PWM Production Department

36. . . Transient load status detection unit

37. . . motor

38. . . Motor rotation speed detecting unit

39. . . Motor rotation number detecting unit

40. . . Step force detection unit

41. . . Vehicle speed detection department

371. . . Hall IC

U, V, W. . . phase

UH, UL, VH, VL, WH, WL. . . Transistor

Claims (10)

A control device for a three-phase brushless motor, comprising: a three-phase bridge converter circuit (15) for supplying a driving voltage to each phase of the three-phase brushless motor (37) (U, V, W) And a complementary intermittent energization driving means (32) for applying a PWM signal having a conduction angle of less than 180 degrees to the transistors (UH, UL, VH, VL, WH, WL) of the inverter circuit (15), And driving the three-phase brushless motor by a complementary intermittent energization driving method, wherein the complementary intermittent energization driving means (32) applies two different phases of the PWM signals to the lower phase of each phase in the three phases of the three phases. And a current flows through the two-phase coil, and one of the three phases is applied with the same PWM signal to the upper and lower transistors, and the energy accumulated in the coil of the one phase passes through any of the upper and lower transistors. By circulating a current, a current flows at a full electrical angle in each phase, and the three-phase brushless motor is driven by complementary intermittent energization. The control device for a three-phase brushless motor according to claim 1, wherein the complementary intermittent energization driving mode is performed in at least one of a start operation state or a transient load state of the three-phase brushless motor The aforementioned three-phase brushless motor is controlled. The control device for a three-phase brushless motor according to claim 2, wherein the device is provided with a 180-degree energization driving means (33), and a PWM signal having a conduction angle of 180 degrees is applied to the inverter circuit (15). And driving the aforementioned three-phase brushless motor (37) with a 180-degree energization drive; The drive mode selection means (31) selects the complementary intermittent energization drive mode in the start-up operation state of the three-phase brushless motor (37), and selects when the operation state of the three-phase brushless motor (37) becomes the normal operation state. 180 degree power-on drive mode. The control device for a three-phase brushless motor according to claim 3, wherein the intermittently energizing driving means (34) applies a PWM signal having a conduction angle of less than 180 degrees to the inverter circuit. (15) driving the three-phase brushless motor (37) by intermittent energization driving; the driving mode selecting means (31) is when the transient load state of the three-phase brushless motor (37) is detected , select intermittent power drive mode. The control device for a three-phase brushless motor according to claim 4, wherein the driving mode selection means (31) is after the transient load state is detected and the intermittent energization driving mode is selected. When the release of the transient load state is detected, it is restored to the 180-degree energization drive mode. The control device for a three-phase brushless motor according to the third aspect of the invention, wherein the driving mode selection means (31) is such that a rotation speed of the three-phase brushless motor (37) becomes a predetermined value or more, and When the number of rotations of the three-phase brushless motor (37) in the forward rotation direction is continuously detected for a predetermined number of times or more, it is judged that the operation has been shifted from the startup operation state to the normal operation state. Control device for three-phase brushless motor as described in item 4 of the patent application scope The drive mode selection means (31) determines that the reverse rotation of the three-phase brushless motor (37) is in a transient load state. The control device for a three-phase brushless motor according to claim 5, wherein the three-phase brushless motor (37) is used for auxiliary control of a power-assisted bicycle; and the driving mode selection means (31), The rotation speed of the three-phase brushless motor (37) is equal to or greater than a predetermined value, and the number of rotations of the three-phase brushless motor (37) in the forward rotation direction is continuously detected a predetermined number of times or more, and the electric assist bicycle is When the pedaling force range becomes equal to or lower than the predetermined value, it is judged that the transient load state has been released. The control device for a three-phase brushless motor according to claim 5, wherein the three-phase brushless motor (37) is used for auxiliary control of a power-assisted bicycle; and the driving mode selection means (31), When the rotational speed of the three-phase brushless motor (37) becomes a predetermined value or more and the vehicle speed of the electric assist bicycle becomes equal to or greater than a predetermined value, it is determined that the transient load state has been released. A power-assisted unit for a power-assisted bicycle, comprising: a control device for a three-phase brushless motor according to any one of claims 1 to 9.