JPH07327393A - Starter of motor - Google Patents

Abstract

PURPOSE:To smoothly perform the rotational drive of the rotor of a sensorless and brushless motor. CONSTITUTION:A motor 11 has armature coils 11u, v, w, the neutral point thereof and a rotor 11r, and the drive voltage of a battery 20 is applied to the armature coils 11u, v, w via a switching device 21. By controlling signals SS1-SS6 fed from a drive control part 27, the ON-OFF switchings of switching elements S1-S6 are performed. In the case of starting the motor 11, the excitation of an inverter is performed by a three-phase current application excitation pattern, and after a predetermined time, the excitation pattern is switched to a two-phase excitation pattern. Thereby, the rotation of the motor 11 is made smooth, and as a result, the unevenness of the torque of the motor 11 is made small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor starting device for starting a three-phase sensorless brushless motor having three sets of armature coils that are not grounded and connected to a neutral point.

[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 motor starting method has the following disadvantages.

For example, when the motor is a three-phase sensorless brushless motor having three armature coil groups,
In the normal operation, the motor is driven in a so-called two-phase energization pattern in which six kinds of excitation patterns are sequentially switched to rotate the motor. At the same time, as the excitation switching operation at startup, the motor is driven by the excitation switching operation of the two-phase energization pattern.

However, when the excitation switching operation is performed with this two-phase energization pattern, the rotor of the motor is driven by 60 times each time the excitation is switched.
Since the motor rotates in degrees, the output torque of the motor becomes uneven, and the motor cannot be started smoothly. At the same time, in the energization pattern in which the output torque of the rotor becomes small, the rotor may rotate in the opposite direction.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a motor starter capable of smoothly rotating and driving the rotor of a sensorless brushless motor at the time of start.

[0009]

SUMMARY OF THE INVENTION The present invention is a motor starter for starting a three-phase sensorless brushless motor having three sets of armature coils which are not grounded and connected to a neutral point. A rotating magnetic field position detecting means for detecting the rotating position of the rotating magnetic field based on the point voltage, a start / end determining means for determining the start / end of the motor based on the detection signal of the rotating magnetic field position detecting means, and the electric machine at start-up. After the child coil is excited and switched in a predetermined three-phase energization excitation pattern for a predetermined time, it is energized and switched in a predetermined two-phase energization excitation pattern, and when the activation end determination means determines the end of activation by the excitation switching operation, a predetermined value is determined. It is provided with a motor drive control means for shifting to a normal operation operation.

Further, in a motor starter for starting a three-phase sensorless brushless motor having three sets of armature coils that are not grounded to the neutral point Y, a rotating magnetic field of the rotating magnetic field is generated based on the neutral point voltage of the armature coils. A rotating magnetic field position detecting means for detecting a rotating position, a start / end determining means for judging the start / stop of the motor based on a detection signal of the rotating magnetic field position detecting means, and the armature coil at a predetermined three phase at start-up. After excitation switching is performed for a predetermined time in the AC inverter energization excitation pattern, excitation switching is performed in a predetermined two-phase energization excitation pattern, and when the activation end determination means determines that the activation is completed in the excitation switching operation, a predetermined normal operation operation is performed. The motor drive control means is provided.

[0011]

Therefore, since the excitation is switched in the three-phase energization excitation pattern immediately after the start of the start-up, the change in the rotation angle of the rotor of the motor during the excitation switching becomes smaller,
As a result, the rotation of the motor at the time of start-up becomes smooth, the unevenness of the generated torque is reduced, and it is possible to avoid a situation in which the rotor is rotated in the reverse direction.

Further, in the state immediately after the start of the start-up, the excitation is switched in the three-phase AC inverter energization excitation pattern, so that the rotation angle of the rotor of the motor changes continuously, so that the rotation of the motor at the start-up becomes smooth. At the same time, the unevenness of the generated torque is reduced, and it is possible to avoid a situation in which the rotor is reversed.

[0013]

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 equal to 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 determining section 28 receives the input signal SC
If 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, 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 controller 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, at the time of starting, the armature coils 11u, 11v, 11 of the motor 11.
After w is excited to the initial setting state for a predetermined time, after that, a predetermined start-time excitation switching operation is performed until the start end determination signal DS is output from the start end determination unit 28, and when the start is finished, the gate circuit 25 outputs The armature coil 1 of the motor 11 corresponding to the change in the logic level of the signal SC5 to be generated.
The normal operation is performed by exciting 1u, 11v, and 11w with a predetermined excitation pattern (two-phase energization excitation pattern). In the normal driving operation, the motor drive control unit 27 also controls the control signals SS1, SS2, SS3, SS4, SS corresponding to the position signal SP output from the accelerator device.
5, set the level of SS6, so that the motor 11
The magnitude of the drive current applied to the armature coils 11u, 11v, and 11w is set.

Then, in the normal operation processing, the motor drive control unit 27, as shown in FIGS. 3 (a) to 3 (f),
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 (two-phase energization excitation pattern). Here, the control signals SS1, SS2, SS
The low level of 3, SS4, SS5, SS6 is equal to the level "0", and the control signals SS1, SS2, SS
The high level of 3, SS4, SS5, SS6 is a voltage value corresponding to the position signal SP at that time when the magnitude of the drive current is controlled by the level control of the control signals SS1 to SS6.

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, and PT6, the rotor 11r of the motor 11 rotates in a predetermined direction at a predetermined speed.

When the patterns PT1 to PT6 are switched to, 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, SC3 output from the comparators 22, 23, 24 in accordance with 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 level 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.

That is, by detecting the level change of the signal SC5, it can be determined whether or not the motor 11 is in a 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.

On the other hand, in the start-up process, the motor drive control section 27, as shown in FIGS. 4 (a) to 4 (f), immediately after the start-up, the motor drive control section 27 controls signals SS1, SS2, SS3, SS.
4, SS5, SS6 level, pattern PT1a, P
T1b, PT2a, PT2b, PT3a, PT3b, P
T4a, PT4b, PT5a, PT5b, PT6a, P
The motor 11 is driven by a three-phase energization excitation pattern that is sequentially switched to 12 types of T6b.

In this way, the control signals SS1, SS2, S
S3, SS4, SS5 and SS6 are replaced by the patterns PT1a,
PT1b, PT2a, PT2b, PT3a, PT3b,
PT4a, PT4b, PT5a, PT5b, PT6a,
By sequentially switching to PT6b, the rotor 11r of the motor 11 rotates in a predetermined direction at a predetermined speed. At the same time, the rotation position is switched by 30 ° each time the excitation is switched.

When the motor 11 is driven in the three-phase energization / excitation switching pattern in this way, the angle at which the rotor 11r rotates each time the excitation is switched is ½ of that in normal operation in FIG. Rotation will be smooth.

FIG. 5 shows a processing example of the motor drive control unit 27.

The motor drive control unit 27 monitors that the position signal SP has changed (NO loop of judgment 101), 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
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.

Since the position signal SP has changed and the value after the change is at an operation position other than "motor off", the judgment 1
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 (step 106), a predetermined three-phase energization start processing is started (step 107), and the three-phase energization start processing is performed for a predetermined time TA.
It is executed and waits until the rotation speed of the rotor 11r of the motor 11 increases to some extent (NO loop of decision 108).
Here, the three-phase energization start-up process means the control signals SS1 to SS.
The value of 6 is set in a pattern of a predetermined initial setting state, the initial setting state is maintained for a predetermined time, and the levels of the control signals SS1 to SS6 are changed to the pattern PT at a predetermined start-up switching cycle.
1a, PT1b, PT2a, PT2b, PT3a, PT
3b, PT4a, PT4b, PT5a, PT5b, PT
6a and PT6b are three-phase energization excitation patterns for driving.

In this way, when the rotational speed of the rotor 11r of the motor 11 increases to some extent in the three-phase energization start-up process and the result of the judgment 108 becomes YES, the motor drive control unit 2
7 starts a predetermined two-phase energization start process (process 10).
9). Here, the two-phase energization start-up process means the control signal SS1.
~ SS6 level is set to patterns PT1, PT2, PT
This is an operation of driving with a two-phase energization excitation pattern of 3, PT4, PT5, PT6.

As a result, the armature coils 11u, 11
At the neutral point 11n of v and 11w, the voltage V as described above is applied.
Since n occurs, the activation end determination unit 28 can perform the activation end determination operation described above. Therefore, the motor drive control unit 27 waits until the activation end determination signal DS is output from the activation end determination unit 28 (NO loop of determination 110).

When the start of the motor 11 is completed, a judgment 118 is made.
When the result is YES, the level of the control signals SS1 to SS6 is switched to the patterns PT1 to PT6 (two-phase energization pattern) by referring to the signal SC5, and the value of the driving current is changed to the operation of the position signal SP at that time. Start the normal operation process to control the size corresponding to the position (Process 1
11), the motor 11 is normally operated, and the process returns to the determination 101.

Further, when the motor speed is changed in the normal operation state and the result of judgment 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
2) Return to decision 101.

In this way, in this embodiment, the excitation switching pattern of the motor 11 is set to 12 kinds of 3 immediately after the start.
Since the phase energization excitation pattern is set, the angle at which the rotor 11r rotates each time the excitation is switched is 1 during normal operation.
Since the rotation magnetic field moves smoothly, the torque generated by the motor 11 becomes less uneven, and problems such as the reverse rotation of the rotor 11r are prevented and stable starting operation is performed. You can

In the above-described embodiment, the motor 11 is driven by the three-phase excitation energization pattern so that the rotation of the motor 11 becomes smooth immediately after the motor 11 is started.
Motor 1 with a well-known 3-phase AC inverter energization excitation pattern
When 1 is driven, the rotation of the rotor 11r becomes continuous,
The rotation of the motor 11 becomes smoother.

An example of this three-phase AC inverter energization excitation pattern is shown in FIGS. 6 (a) to 6 (f).

In addition to the above, the three-phase AC inverter energization excitation pattern includes, for example, an energization excitation pattern by the triangular wave comparison PWM method which can make the rotation of the motor 11 smoother.

By the way, in the above-mentioned embodiment, the present invention is applied to the activation of the sensorless brushless motor mounted on the electric bicycle. However, the activation of the sensorless brushless motor mounted on other devices is also
The present invention can be similarly applied.

[0058]

As described above, according to the present invention,
In the state immediately after the start of the start-up, the excitation is switched in the three-phase energization excitation pattern, so that the change in the rotation angle of the rotor of the motor at the time of the change-over of excitation becomes smaller, and the rotation of the motor at the start becomes smoother. At the same time, the unevenness of the generated torque is reduced, and it is possible to avoid the situation in which the rotor is reversed.

Further, in the state immediately after the start-up, since the excitation is switched in the three-phase AC inverter energization excitation pattern, the rotation angle of the rotor of the motor changes continuously, so that the rotation of the motor at the start-up becomes smooth. At the same time, the unevenness of the generated torque is reduced, and it is possible to avoid the situation in which the rotor is reversed.

[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 an operation waveform diagram showing an example of a three-phase energization excitation pattern.

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

FIG. 6 is an operation waveform diagram showing an example of a three-phase AC inverter energization excitation pattern.

[Explanation of symbols]

 11 motors 11u, 11v, 11w armature coils 11r rotor 20 battery 21 switching device 22, 23, 24 comparator 25 gate circuit 26 OR circuit 27 motor drive control unit 28 start end determination unit

Claims (2)

[Claims] 1. A motor starter for starting a three-phase sensorless brushless motor having three sets of armature coils that are not grounded to a neutral point Y, wherein a rotating magnetic field of a rotating magnetic field is generated based on a neutral point voltage of the armature coils. A rotating magnetic field position detecting means for detecting a rotating position, a start / end determining means for determining start / end of the motor based on a detection signal of the rotating magnetic field position detecting means, and at the time of starting, the armature coil is provided with a predetermined three-phase After switching the excitation for a predetermined time in the energization excitation pattern, the excitation is switched over in a predetermined two-phase energization excitation pattern, and when the activation end determination means determines the completion of the activation by the excitation switching operation, the motor shifts to a predetermined normal operation operation. A motor starter comprising drive control means. 2. A motor starter for starting a three-phase sensorless brushless motor having three sets of armature coils that are not grounded with a neutral point Y, wherein a rotating magnetic field of a rotating magnetic field is generated based on a neutral point voltage of the armature coil. A rotating magnetic field position detecting means for detecting a rotating position, a start / end determining means for determining start / end of the motor based on a detection signal of the rotating magnetic field position detecting means, and at the time of starting, the armature coil is provided with a predetermined three-phase After switching the excitation in the AC inverter energization excitation pattern for a predetermined time, the excitation is switched in a predetermined two-phase energization excitation pattern, and when the activation end determination means determines the activation end by the excitation switching operation, it shifts to the predetermined normal operation operation. A motor starting device, comprising: