JP3389326B2 - Motor starter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensorless brushless motor having a neutral-point non-grounded Y-connected armature coil, and a neutral-point non-grounded Y-connected armature coil, which is unidirectional. The present invention relates to a motor starter that starts a sensorless brushless motor connected to a load via a clutch mechanism.

[0002]

2. Description of the Related Art Generally, a sensorless brushless motor (hereinafter, simply referred to as a motor) does not include a rotor position detecting sensor such as a hall element, and therefore, the rotational speed of the rotor reaches a predetermined value or more and is not energized. The position of the rotor cannot be detected unless a predetermined induced voltage is generated in the armature coil.

Therefore, for example, as disclosed in JP-A-1-30819 (method for starting a sensorless brushless motor), the armature coil of the motor is excited to the initial setting state for a predetermined time, and thereafter, A sensorless brushless motor is started by a method of performing a predetermined excitation switching operation at startup until the rotation speed of the motor rotor reaches a predetermined value.

When the rotational speed of the rotor of the motor reaches a predetermined value, thereafter, the rotational position of the rotor is detected based on the voltage change at the neutral point of the armature coil group, and based on the detection result. The operation shifts to normal operation in which the armature coil is switched to excitation.

[0005]

However, such a conventional starting method has the following disadvantages.

That is, for example, at the first time when the armature coil of the motor is excited to the initial state, the rotor RT of the motor and the rotating magnetic field F formed by the armature coil.
It is assumed that the direction of F is in the state as shown in FIG. Here, the rotation direction of the rotor RT is assumed to be the clockwise direction in the figure.

At this time, the rotor RT is shown in FIG.
As shown in (c) and (d), it gradually rotates in the rotational direction so as to follow the direction of the rotating magnetic field FF.
In the state in which it has rotated to the state of the initial state of, it stops.

Thus, the rotor RT is shown in FIG.
From the state where the rotational position is indefinite as shown in Fig. 11,
When rotating to the state of the initial state of (d), for example, since the torque generated in the motor at the rotational position of the rotor RT as shown in (a) and (c) of FIG. The time required to rotate from the rotational position shown in FIG. 7A to the rotational position shown in FIG.
It takes a relatively long time for the rotor RT to rotate from the rotational position shown in FIG. 7C to the initial rotational position shown in FIG.

Therefore, it has been necessary to set the period for exciting in the initial state to be long to some extent, resulting in a situation in which the time required until the motor finishes starting becomes long.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a motor starter capable of reducing the time required for starting a sensorless brushless motor.

[0011]

SUMMARY OF THE INVENTION The present invention provides a motor starter for starting a sensorless brushless motor having a neutral point non-grounded Y-connected armature coil.
The armature coil is energized in such a manner that excitation switching is performed for a predetermined period with an excitation pattern that rotates in a predetermined rotation direction at a predetermined start positioning time period, and then continuously rotates in a predetermined rotation direction at a predetermined start time period. The motor drive control means for switching is provided. Also, the start positioning cycle is
It is preferable to set the cycle longer than the startup cycle.

Further, in a motor starter having an armature coil connected to a neutral point non-grounded Y-connection and for starting a sensorless brushless motor connected to a load through a one-way clutch mechanism, the armature is started at the time of starting. The motor drive control means is provided for switching the coil to an excitation pattern that rotates in the reverse rotation direction for a predetermined period of excitation, and then switching the excitation to a mode of continuously rotating in the predetermined rotation direction.

[0013]

Therefore, by switching the excitation pattern of the armature coil at a slow cycle for a predetermined period of at least one rotation or more, the direction of the rotating magnetic field formed by the armature coil matches the direction of the rotor whose rotational position is indefinite. Since the continuous excitation switching at the time of starting can be performed immediately after that, the time required at the time of starting can be shortened.

When the motor and the load are connected to each other through the one-way clutch mechanism as in an electric bicycle, the armature coil is formed by rotating in the reverse direction of the light load. Since the direction of the rotating magnetic field and the direction of the rotor whose rotational position is indefinite can be matched, and the continuous excitation switching operation at the time of startup can be immediately performed thereafter, the time required at startup can be greatly reduced. .

[0015]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 shows an electric bicycle according to an embodiment of the present invention.

In FIG. 1, the electric bicycle 1 includes a frame 2, a front wheel 3, a rear wheel 4, a handle 5, a saddle 6, a pedal 7, and a transmission mechanism 8 for transmitting the power of the pedal 7 to the rear wheel 4. It is configured.

The disk-shaped housing 10 provided on the hub 9 of the rear wheel 4 is provided with a motor 11 and a transmission mechanism (not shown) for transmitting the power of the motor 11 to the drive shaft of the rear wheel 7. Has been. The transmission mechanism includes a motor 11
A one-way clutch mechanism (for example, a ratchet) is provided for temporarily releasing the connection between the motor shaft and the rear wheel shaft when the rotation speed of the shaft and the rotation speed of the drive shaft of the rear wheel 7 do not match. Further, a sensorless brushless motor is used as the motor 11 because of its good maintainability and good riding comfort. A battery box 13 for accommodating a battery for supplying electric power to the motor 11 is arranged on the luggage carrier 12 provided on the upper portion of the rear wheel 7.

The right hand grip 14 of the handle 5 is provided with an accelerator device for allowing the user to specify the on / off and speed of the motor 11. For example, in the accelerator device, it is possible to operate the motor 11 at a position for designating OFF, a position for designating a low speed, a position for designating a medium speed, and a position for designating a high speed. , Is output to a motor control device described later. Also,
The handle 5 has a brake 15 for stopping the vehicle body,
16 are provided.

FIG. 2 shows an example of a motor control device for driving and controlling the motor 11. In this case,
The motor 11 is a sensorless brushless motor.

In the figure, the motor 11 includes armature coils 11u, 11v, and 11w that are Y-connected to the neutral point and not grounded.
And a rotor 11r that forms a rotating magnetic field, and the driving power source of the battery 20 is applied to the armature coils 11u, 11v, and 11w via the switching device 21.

The switching device 21 is connected in series between the positive pole and the negative pole of the battery 20.
It consists of three switching elements connected in parallel. The interconnection point of the switching elements S1 and S2 connected in series is the armature coil 11
The interconnection end of the switching element S3 and the switching element S4, which are connected to the other end of u and are connected in series, are connected to the other end of the armature coil 11v, and the switching element S5 and the switching element are connected in series. The interconnection end of S6 is connected to the other end of the armature coil 11w. Here, the switching elements S1, S2, S3, S
4, S5 and S6 are composed of FETs and protective diodes.

The voltage Vn at the interconnection point of the armature coils 11u, 11v, 11w, that is, at the neutral point 11n is determined by the plus side input end of the comparator 22, the plus side input end of the comparator 23, and the comparator 24. Are added to the negative input terminals of.

The voltage dividing resistors R1 and R2 divide the voltage E of the battery 20 into 1/2, and the voltage (E / 2) at the voltage dividing point is applied to the negative side input terminal of the comparator 22. Has been. The voltage dividing resistors R3, R4 and R5 are connected to the battery 20.
Voltage E is divided into 1/3 and 2/3,
The voltage (2E / 3) at the voltage dividing point of 2/3 is the comparator 23
, And the voltage (E / 3) at the voltage dividing point of 1/3 is applied to the positive input terminal of the comparator 24.

In the comparator 22, the voltage Vn is the voltage (E / 2).
If it is larger than the above, the comparison signal SC1 of logic H level is output and the voltage Vn is equal to the voltage (E /
3) In the following cases, the comparison signal SC1 of logic L level is output, and the comparison signal SC1 is added to the gate circuit 25.

In the comparator 23, the voltage Vn is the voltage (2E /
When it is larger than 3), the comparison signal SC2 of logic H level is output and the voltage Vn is equal to the voltage (2
E / 3) or less, a logical L level comparison signal SC
2 is output, and the comparison signal SC2 is applied to one input terminal of the OR circuit 26.

In the comparator 24, the voltage Vn is the voltage (E / 3).
If it is smaller than the above, the comparison signal SC3 of logic H level is output, and the voltage Vn is equal to the voltage (E /
3) In the above cases, the comparison signal SC3 of logical L level is output, and the comparison signal SC3 is applied to one input terminal of the OR circuit 26.

The output of the OR circuit 26 is the gate control signal S
C4 is added to the control signal input terminal of the gate circuit 25.

The gate circuit 25 receives the gate control signal SC4.
Is at a logic L level, the input comparison signal SC1 is passed as it is and is output as a signal SC5, while when the gate control signal SC4 rises to a logic H level, the signal SC5 is output at the time of its rise. The signal SC5 is applied to the motor drive control unit 27 and the activation end determination unit 28.

The start / end determination unit 28 determines whether the input signal SC
The logic level of 5 periodically changes to the logic H level and the logic L level, and the period of being the logic H level and the period of being the logic L level are the same time,
If the state continues for a predetermined time, the motor 11
It is determined that the rotation speed of the rotor 11r has reached a sufficient value and the startup has ended, and the startup end determination signal DS representing the determination result is added to the motor drive control unit 27.

The motor drive control unit 27 includes switching elements S1, S2, S3, S4, S of the switching device 21.
Control signals SS1, SS2, SS3 to 5 and S6, respectively.
SS4, SS5, SS6 are output to switch the on / off states of the switching elements S1, S2, S3, S4, S5, S6, whereby the armature coil 1 of the motor 11 is switched.
The excitation states of 1u, 11v, and 11w are switched.

Here, the motor drive control unit 27 sets the rotor 11r of the motor 11 to a predetermined initial state at the time of start, and then performs a predetermined start until the start end determination unit 28 outputs the start end determination signal DS. When the time excitation switching operation is performed and the start-up is completed, the motor 1 responds to the change in the logic level of the signal SC5 output from the gate circuit 25
The normal operation operation of exciting the one armature coil 11u, 11v, 11w in a predetermined excitation pattern is performed. Further, the motor drive control unit 27 sets the magnitude of the drive current applied to the armature coils 11u, 11v, 11w of the motor 11 corresponding to the position signal SP output from the accelerator device in the normal driving operation. As a method of setting the drive current, a well-known PWM control method or a control signal S
There are level control methods of S1 to SS6.

Then, in the normal operation processing, the motor drive control unit 27, as shown in FIGS.
Control signals SS1, SS2, SS3, SS4, SS5, S
Set the level of S6 to patterns PT1, PT2, PT3, PT
4, PT5, PT6 are sequentially switched. Here, control signals SS1, SS2, SS3, SS4, SS5, SS6
Of the control signal SS1, SS2, SS3, SS4, SS5, SS6 is a voltage value corresponding to the position signal SP at that time.

In this way, the control signals SS1, SS2, S
S3, SS4, SS5 and SS6 are replaced with patterns PT1 and P
By sequentially switching to T2, PT3, PT4, PT5, PT6, the rotor 11r of the motor 11 rotates at a predetermined speed.

When the patterns PT1 to PT6 are switched, the armature coils 11u, 11v, 11w respectively.
The terminal voltages Vu, Vv, and Vw of FIG.
As shown in (i), the voltage Vn at the neutral point 11n of the armature coils 11u, 11v, 11w changes accordingly.
Changes as shown in FIG. Here, the terminal voltages Vu, Vv, and Vw include switching elements S1 to S6.
Noise SK on the pulse generated when switching on and off
, The noise component SKa is also included in the voltage Vn.

Therefore, the comparison signals SC1, SC2 and SC3 output from the comparators 22, 23 and 24, respectively, according to the level change of the voltage Vn are shown in FIG.
Changes as shown in (l) and (m), and
The gate control signal SC4 output from the OR circuit 26 is
It changes as shown in FIG.

That is, the gate control signal SC4 changes from the logic L level to the logic H at the timing immediately before the signal component of the noise component SKa of the voltage Vn is output to the comparison signal SC1.
As the voltage rises to the level, the motor drive control unit 27 changes to a mode in which the motor drive control unit 27 falls to the logical L level immediately before the edge required for the excitation switching operation appears.

As a result, the signal SC5 output from the gate circuit 25 becomes the comparison signal S, as shown in FIG.
The signal of the noise component SKa contained in the voltage Vn is removed from C1.

The motor drive controller 27 sends this signal SC5
Has a rising edge that rises from the logic L level to the logic H level and a fall edge that falls from the logic H level to the logic L level at predetermined electrical angles (for example, 30 degrees) corresponding to the excitation switching cycle at that time. In the delayed state, the patterns PT1 to P of the control signals SS1 to SS6
The switching operation of T6 is performed.

In this way, in the state where the motor 11 is normally operating, the rotor 11r has a sufficient rotation speed, so that the voltage Vn of the neutral point 11r of the armature coils 11u, 11v, 11w is appropriate. Signal SC5 changes to a logic H level and a logic L level periodically, and
The period T1 of the logic H level and the period T2 of the logic L level have almost the same value, and the state is stable.

That is, by detecting the level change of the signal SC5, it can be determined whether or not the motor 11 is in the state where the normal operation processing can be applied.
This is adopted as the determination condition for the activation end determination unit 28 to determine the activation end, as described above.

Here, in this embodiment, the following operation is performed when the rotor 11r is set to the initial state in the starting process of the motor 11.

That is, the levels of the control signals SS1 to SS6 are sequentially switched to the patterns PT1 to PT6 at a cycle longer than the excitation switching cycle at the time of normal startup excitation switching.
The direction of the magnetic field generated by the armature coils 11u, 11v, 11w is rotated once (the rotation direction is the direction FR).

At this time, for example, as shown in FIG. 4A, when the rotor 11r is stopped at a certain rotation position,
In the excitation period of the first pattern PT1, the armature coil 1
The direction of the magnetic field formed by 1u, 11v, and 11w is the direction FF.
In the excitation period of the next pattern PT2, the direction of the magnetic field formed by the armature coils 11u, 11v, 11w is the direction FF2 shown in FIG.
In the excitation period of T3, the armature coils 11u, 11v, 1
The direction of the magnetic field formed by 1w is the direction F shown in FIG.
F3, and this direction FF3 is a direction following the rotational position of the rotor 11r. Therefore, during this excitation period, the rotor 11r
The state of r is synchronized with the rotating operation of the rotating magnetic fields of the armature coils 11u, 11v, 11w.

Therefore, the subsequent patterns PT4 and
In the excitation period of PT5, PT6, (d), (e),
As shown in (f), the armature coils 11u, 11v, 1
The rotor 11r rotates so as to follow the direction of the magnetic field formed by 1w.

In this way, the armature coils 11u, 1u
When the rotating magnetic field generated by 1v and 11w is rotated at a slow speed, the rotor 1 is rotated at any one of the rotating positions.
The direction of 1r coincides with the direction of the rotating magnetic field, and thereafter, the rotor 1 is synchronized with the rotation of the rotating magnetic field.
1r rotates.

That is, with the excitation switching period longer than usual,
When the excitation switching operation for one rotation of the rotating magnetic field is performed, when the operation is completed, the rotating magnetic field and the rotor 11r are in a synchronized state, and thereafter, the normal startup excitation switching operation is properly performed. It can be carried out. As a result, the rotor 11
The time required to position the position r in the initial state is shortened, and the startup time of the motor 11 can be shortened.

FIG. 5 shows an example of processing of the motor drive controller 27.

The motor drive control unit 27 monitors that the position signal SP has changed (NO loop of judgment 101), and the position signal SP has changed and the result of judgment 101 is Y.
When it becomes ES, it is checked whether or not the position signal SP is at the "motor off" operation position (decision 102).

When the result of determination 102 is YES, a flag Foff for storing the state in which the motor 11 is off is set (process 103), and the control signal SS is set.
The changes of 1 to SS6 are stopped, the excitation switching operation of the motor 11 is stopped, the motor 11 is stopped (process 104), and the process returns to the determination 101.

The position signal SP changes, and the value after the change is at an operation position other than "motor off".
When the result of 02 is NO, it is checked whether or not the flag Foff is set (decision 105).

When the result of determination 105 is YES, it means that the motor has been switched from the "motor off" state to the operating position for designating one of the speeds. Therefore, at this time, the motor 11 is started.

That is, first, the flag Foff is cleared (process 106), and a predetermined starting process is started (process 1).
07), the activation end determination signal DS from the activation end determination unit 28
Waits until is output (NO loop of decision 108).

When the start of the motor 11 is completed, the decision 108 is made.
When the result is YES, the level of the control signals SS1 to SS6 is switched to the patterns PT1 to PT6 with reference to the signal SC5, and the value of the drive current is set to the magnitude corresponding to the operation position of the position signal SP at that time. Then, the normal operation process for controlling the start is started (process 109), the motor 11 is normally operated, and the process returns to the determination 101.

When the motor speed is changed in the normal operation state and the result of determination 105 is NO, the value of the drive current of the motor 11 corresponds to the operation position of the position signal SP at that time. The value is controlled (Processing 11
0), the process returns to decision 101.

FIG. 6 shows an example of the starting process.

First, the excitation switching cycle is set to a value for a predetermined alignment longer than usual (process 201), and the levels of the control signals SS1 to SS6 are changed to patterns PT1 to PT6 at the set excitation switching cycle. By sequentially switching, the rotating magnetic field is rotated once (process 202), and the rotor 11r is synchronized with the direction of the rotating magnetic field.

Next, the excitation switching cycle is changed to the value at the time of starting (process 203), and thereafter, the levels of the control signals SS1 to SS6 are changed to the pattern P at the set excitation switching cycle.
The rotating magnetic field is continuously rotated by sequentially switching to T1 to PT6 (process 204).

By the way, in the electric bicycle 1, since the shaft of the motor 11 and the rear wheel 4 are connected via the one-way clutch mechanism as described above, as shown in FIG.
The load LDb when driving 1 in the reverse direction BW is a value that is significantly smaller than the load LDf when driving the motor 11 in the forward direction FR.

Therefore, when starting up, the rotor 1 of the motor 11 is
When the rotation of 1r is synchronized with the movement of the rotating magnetic field, if the rotating magnetic field is rotated in the opposite direction, the rotor 11r can be synchronized with the rotating operation of the rotating magnetic field even if the rotation speed is relatively high. As a result, the time required to synchronize the rotation of the rotor 11r with the movement of the rotating magnetic field can be significantly reduced.

That is, in this case, FIGS.
As shown in, the rotating magnetic field is applied in the reverse direction B in directions FF5 to FF6.
When the rotor 11r makes one rotation in W, the direction of the rotor 11r follows the direction FF6 of the rotating magnetic field, so the rotor 11r is stopped in that state (see (g) in the same figure), and thereafter, the rotating magnetic field is rotated in the normal direction. .

In order to rotate the rotating magnetic field in the reverse direction BW, as shown in FIGS. 9 (a) to 9 (f), the control signal SS1
~ SS6 may be switched to a mode opposite to the forward rotation direction.

FIG. 10 shows the motor drive control unit 2 in this case.
7 shows an example of the processing executed by 7 at the time of startup.

First, the motor drive control section 27 sequentially switches the levels of the control signals SS1 to SS6 to the driving mode of the reverse direction BW at a predetermined excitation switching cycle, and the rotating magnetic field makes one rotation in the reverse direction BW. (Process 301), rotor 11
r is synchronized with the direction of the rotating magnetic field.

Then, the levels of the control signals SS1 to SS6 are changed to patterns PT1 to PT at a predetermined excitation switching cycle at the time of activation.
6, the rotating magnetic field is continuously rotated in the forward rotation direction FR (process 302).

By the way, in each of the above-described embodiments, the number of times the rotating magnetic field is rotated in the forward rotation direction or the reverse rotation direction at startup is set to one. In some cases, the synchronization of the rotor 11r of the motor 11 cannot be established. In such a case, it is preferable to set the number of rotations of the rotating magnetic field at the time of startup to an appropriate value of 2 or more so that the synchronization between the rotating magnetic field and the rotor 11r can be established.

By the way, in the above-mentioned embodiment, the case where the three-phase sensorless brushless motor is used as the motor has been described, but the present invention is similarly applied to the case where the sensorless brushless motor of the other number of phases is used. can do.

Further, in the above-mentioned embodiment, regarding the activation of the sensorless brushless motor mounted on the electric bicycle,
Although the present invention is applied, the present invention can be similarly applied to the case of starting a sensorless brushless motor mounted on another device.

[0069]

As described above, according to the present invention,
By switching the excitation pattern of the armature coil in a slow cycle for a predetermined period of at least one rotation or more, it is possible to match the direction of the rotating magnetic field formed by the armature coil with the direction of the rotor whose rotational position is indefinite. After that, the continuous excitation switching at the time of starting can be immediately performed, so that the time required for starting can be shortened.

When the motor and the load are connected to each other through the one-way clutch mechanism as in an electric bicycle, the armature coil is formed by rotating in the reverse direction of the light load. Since the direction of the rotating magnetic field and the direction of the rotor whose rotational position is indefinite can be matched, and the continuous excitation switching operation at the time of startup can be immediately performed thereafter, the time required at startup can be greatly reduced. You also get the effect.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an electric bicycle according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a motor control device according to an embodiment of the present invention.

FIG. 3 is an operation waveform diagram for explaining an operation during normal operation.

FIG. 4 is a schematic diagram for explaining an example of an operation when synchronizing the rotation of the rotor of the motor with the movement of the rotating magnetic field.

FIG. 5 is a flowchart showing an example of processing of a motor drive control unit.

FIG. 6 is a flowchart showing an example of startup processing.

FIG. 7 is a schematic diagram for comparing the magnitudes of loads in the forward rotation direction and the reverse rotation direction of the motor.

FIG. 8 is a schematic diagram for explaining another example of the operation when synchronizing the rotation of the rotor of the motor with the movement of the rotating magnetic field.

FIG. 9 is an operation waveform diagram showing an example of an excitation switching pattern when the motor is driven in the reverse direction.

FIG. 10 is a flowchart showing another example of the startup process.

FIG. 11 is a schematic diagram for explaining an inconvenience at the time of starting the conventional device.

[Explanation of symbols]

11 motor 11u, 11v, 11w armature coil 11r rotor 20 battery 21 Switching device 22, 23, 24 comparator 25 gate circuit 26 OR circuit 27 Motor drive controller 28 Start-up determination unit

─────────────────────────────────────────────────── --- Continuation of front page (56) References JP-A-4-101696 (JP, A) JP-A-5-310176 (JP, A) JP-A-4-340392 (JP, A) JP-A-6- 141588 (JP, A) JP-A-6-105592 (JP, A) JP-A-6-105589 (JP, A) JP-A-62-230392 (JP, A) JP-A-61-52194 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02P 6/20 B62M 23/02 H02P 6/16

Claims (2)

(57) [Claims] 1. A motor starter for starting a sensorless brushless motor having an armature coil that is not grounded with a neutral point and is Y-connected, wherein the armature coil is rotated for a predetermined period at a predetermined start positioning cycle at the time of starting. a predetermined period of time excitation switchable excitation pattern which rotates in a direction, then, a motor drive control means for exciting switching the mode to continuously rotate in a predetermined rotational direction at a predetermined startup period, during the start position
The cycle is set to a predetermined fixed cycle that is longer than the startup cycle.
Motor starting device comprising that you are constant. 2. A motor starter for starting a sensorless brushless motor, comprising an armature coil connected to a non-neutralized, neutral Y-connection, and connected to a load via a one-way clutch mechanism. Coil in front
The one-way clutch is switched to the excitation pattern for a predetermined period by the excitation pattern in which the one-way clutch rotates in the reverse rotation direction where it is not connected to the load, and the rotor
Rotate at least one rotation to rotate the rotor in a rotating magnetic field
The one-way clutch to engage the load.
A motor starter comprising motor drive control means for switching the excitation in a manner of continuous rotation in a predetermined rotation direction.