JP2000037093A - Regenerative control method for motor and motor driver with regenerative function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize regenerative operation while ensuring detection accuracy of the rotational position of rotor by performing the regenerative operation for returning power generated in an exciting coil to the power supply side during an interval when an exciting current is not fed to the exciting coil. SOLUTION: Even during an interval when an exciting current is not fed to each exciting coil 25-27, power generated in each exciting coil 25-27 can be regenerated to a smoothing capacitor 31 on the power supply side during commutation spike voltage generating interval and delay interval at the time of determining conduction switching timing. Consequently, rotational position of rotor is detected based on a counter electromotive force induced in each exciting coil 25-27 of a three-phase hybrid stepping motor 28. According to the arrangement, regenerating braking can be performed while ensuring detection of the rotational position of rotor even for a sensorless three-phase hybrid stepping motor 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerative control method for a motor such as a stepping motor or a DC brushless motor, and to a drive device having a regenerative function for such a motor.

[0002]

2. Description of the Related Art For example, an ink jet printer prints characters and pictures on a sheet by ejecting ink to a commanded position while reciprocating a print head. Motor is C
It is called an R drive motor, and for example, a hybrid type stepping motor is used.

An example of the mechanical structure of such a conventional hybrid type stepping motor will be described with reference to FIGS.

In this hybrid type stepping motor, as shown in FIG. 5, upper and lower sides of a case 1 are opened, and bearings 2 and 3 are arranged in the opening, and the rotating shaft 4 is rotatable by the bearings 2 and 3. Supported. A rotor (rotor) 5 is attached to the rotating shaft 4. Rotor 5
Is composed of a magnet 6 inserted through and fixed to the rotating shaft 4, and rotor magnetic poles 7 and 8 inserted through the rotating shaft 4 and fixed above and below the magnet 6. The magnet 6 is magnetized in the thickness direction (axial direction), and the rotor magnetic poles 7 and 8 are formed by stacking laminated steel plates.

A stator 9 is arranged around the rotor 5 concentrically with the rotor 5 (see FIG. 6). A plurality (6 to 9) of the stator 9 are arranged on the rotor 5 side of the stator 9. Stator pole 10
Are provided at equal intervals, and each stator magnetic pole 10 and the rotor 5 are opposed to each other with a gap having a predetermined width. An excitation coil 11 is wound around each stator pole 10.

As shown in FIG. 6, a plurality of (for example, six) small tooth poles 10a are provided at the tip of the stator magnetic pole 10 so as to be distributed to the left and right from the center. As shown in FIG. 6, a large number (for example, 36
) Small tooth poles 7a are formed. Similarly, a large number (for example, 36) of small teeth (not shown) are also formed on the outer periphery of the rotor magnetic pole 8. Small tooth pole 7a of this rotor magnetic pole 7
The rotor teeth 8 and the small teeth of the rotor magnetic pole 8 are arranged in a state of being shifted by a half pitch, that is, in a state of being shifted by 180 ° in electrical angle in phase.

In the stepping motor having such a configuration, the rotor 5 is rotated by switching the current flowing through the exciting coil 11 in synchronization with a pulse input from the outside, and the positioning thereof can be easily performed. The circuit can be easily configured. Also, a hybrid type stepping motor is suitable as a CR drive motor because it can realize an electrically fine step angle.

By the way, although the drive circuit of the stepping motor can be simply constructed, on the other hand, unlike a DC brushless motor or the like, a current flows through the exciting coil regardless of the position of the rotor, so that the rotor vibrates to cause uneven rotation and noise. Cause Further, since a current having a sufficient margin for the load is supplied to the exciting coil to prevent the step-out, there is a disadvantage that the heat generated by the motor is large.

Therefore, a method of driving a stepping motor capable of realizing smooth rotation and low noise by eliminating the vibration of the rotor is desired.
It is necessary to detect the rotational position of the rotor and supply current to the exciting coil at an appropriate timing. For this purpose, the rotational position of the rotor can be easily detected by providing an encoder. However, there are inconveniences such as installation space, cost, and the inability to magnetize the encoder magnet, which is not practical. Therefore, it can be said that a position sensorless type motor that uses a back electromotive force generated in the exciting coil to detect the rotational position of the rotor is preferable.

[0010]

When deceleration is performed in a position sensorless motor, a regenerative operation, which is electrical braking, is required.

However, in the case of the position sensorless motor, if the regenerative operation is performed during the detection of the back electromotive force, there is a disadvantage that the rotational position of the rotor cannot be accurately detected. Control compatibility becomes a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a regenerative control method for a motor and a regenerative function of a motor which can perform a regenerative operation while ensuring detection accuracy of a rotational position of a rotor even in a position sensorless type motor. And to provide a driving device with the same.

[0013]

Means for Solving the Problems In order to solve the above problems and achieve the object of the present invention, the inventions according to claims 1 to 4 are configured as follows.

That is, according to the first aspect of the present invention, a point in time at which the back electromotive force generated in the exciting coil of the motor changes from positive to negative or from negative to positive is determined, and a predetermined delay A method of regenerating a motor for rotating the rotor by energizing the excitation coil based on the determined energization switching timing by delaying the energization switching timing of the excitation coil by delaying the time by a time, wherein the generation is generated in the excitation coil. The regenerative operation that returns power to the power supply side is
The operation is performed during a period in which no exciting current is supplied to the exciting coil.

According to a second aspect of the present invention, there is provided the regenerative control method for a motor according to the first aspect, wherein a spike generated when the energizing coil is energized is switched during a period in which no exciting current is supplied to the exciting coil. The regenerative operation is performed during at least one of a voltage generation period and the delay time.

According to a third aspect of the present invention, a switching means comprising a plurality of switching elements for sequentially energizing a plurality of exciting coils of the motor, and comparing each back electromotive force generated in the plurality of exciting coils with a predetermined voltage. Position detecting means for generating a rotor position signal indicating the rotational position of the rotor, and detecting a change time point of the rotor position signal generated by the position detecting means, and a predetermined time based on the detected change time point. Energization switching timing determination means for delaying the delay time to determine the energization switching timing of each excitation coil, energization signal generation means for generating an energization signal based on the energization switching timing determined by the energization switching timing determination means, The switching element of the switching means is switched based on the energization signal generated by the energization signal generation means. And a predetermined switching element among the switching elements is turned on and off during a period in which no exciting current is supplied to the respective exciting coils, and the power generated in the respective exciting coils is returned to the power supply side. And regenerative control means for performing regenerative control.

According to a fourth aspect of the present invention, in the driving device with a regenerative function of the motor according to the third aspect, the regenerative control means is configured not to supply an exciting current to each of the exciting coils, The regenerative control is performed during at least one of a spike voltage generation period generated at the time of switching the energization of each excitation coil and the delay time.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a drive device with a regenerative function for a motor when the present invention is applied to a three-phase hybrid type stepping motor as shown in FIG.

As shown in FIG. 1, the driving device with a regenerative function of the motor according to this embodiment
1, a timing determining and speed detecting unit 22, an adder 40, a control unit 23, a regenerative pulse generator 50, an inverter unit 24, and the like, and the star-connected exciting coils 25 to of a three-phase hybrid type stepping motor 28 2
7 is excited with a predetermined excitation pattern and a predetermined commutation timing as described later, and the motor 28 is controlled as described later.
When deceleration is required, regenerative control for returning the electric power (electric energy) generated in the exciting coils 25 to 27 to the power supply side is performed.

Next, the configuration of each part of the driving device with a regenerative function of the motor will be described with reference to the drawings.

The rotation position detector 21 captures the back electromotive forces Va to Vc generated at both ends of the exciting coils 25 to 27 when the motor 28 rotates, and converts the back electromotive forces Va to Vc to the neutral point of the motor. By comparing with a predetermined voltage, such as a voltage or a voltage half the output DC voltage Ed of the rectifier 30, rotor position signals S1 to S3 indicating the rotational position of the rotor.
Is generated, and the generated rotor position signals S1 to S3 are output to the timing determination and speed detection unit 22.

The timing determining and speed detecting section 22 uses the rotor position signals S1 to S3 from the rotational position detecting section 21 to supply current switching timing signals S1 'to S3' indicating the current switching timing of the exciting coils 25 to 27. Is generated, and the rotational speed of the rotor is obtained.

The timing determining and speed detecting section 22
Receives a command indicating that the regenerative operation is required from the control unit 23, detects a timing at which the regenerative operation is started,
In order to perform the regenerative operation over a period in which the regenerative operation can be performed from the start of the detection, a regenerative operation signal which is at the “H” level during this period is generated.

The adder 40 generates a speed control signal based on the rotation speed from the timing determination and speed detection unit 22 and an external speed command, and outputs the generated speed control signal to the control unit 23. Is configured.

The control unit 23 controls the speed control signal from the adder 40 and a predetermined excitation method (for example, two-phase excitation).
Output the energization signals P1 to P6 for controlling the on / off of the transistors Q1 to Q6 of the inverter unit 24 to excite the excitation coils 25 to 27, and the energization switching timing (commutation timing) is The power supply switching timing signals S1 ′ to S3 ′ output from the determination and speed detection unit 22 are configured to be performed. The energization signals P1 to P6 from the control unit 23 are
It is configured to be supplied to each base of the transistors Q1 to Q6 constituting the inverter unit 24.

When a regenerative operation is required and the regenerative operation signal is received from the timing determination and speed detector 22 when the regenerative operation is required, the control unit 23 generates the regenerative pulse generator during the period when the regenerative operation signal is at the "H" level. The regenerative pulse from 50 is supplied to the base of a predetermined one of the transistors Q1 to Q6.

The regenerative pulse generator 50 is configured to generate a regenerative pulse to be supplied to the base of a predetermined one of the transistors Q1 to Q6 during a regenerative operation, as described later.

The inverter section 24 is constituted by a three-phase bridge circuit composed of switching transistors Q1 to Q6, and its output terminals are connected to excitation coils 25 to 27 of the motor. Diodes D1 to D6 are connected in parallel to transistors Q1 to Q6. Although a DC voltage is supplied to the inverter unit 24, the DC voltage is obtained by rectifying an AC voltage from an AC power supply 29 with a rectifier 30. Rectifier 3
A smoothing capacitor 31 for smoothing the output of the rectifier 30 is connected in parallel to the output terminal of 0.

Next, an example of the operation of each part when the driving device with the regenerative function of the motor of the embodiment configured as described above drives the motor 28 will be described with reference to FIG. 1 and FIG.

First, from when the motor 28 is stopped until a predetermined number of revolutions is reached, no back electromotive force can be obtained in the exciting coils 25 to 27 so that the position of the rotor can be specified. Therefore, when the motor is started, the control unit 23 sets each of the excitation coils 25 to
Signals P1 to P2 for energizing 27 in a predetermined order
6 is output. In response to the conduction signals P1 to P6, the transistors Q1 to Q6 of the inverter section 24 conduct, and the excitation coils 25 to 27 are sequentially excited. Accordingly, the rotor rotates synchronously in a so-called open loop in response to the excitation.

As described above, when the motor is started, the excitation time of the excitation pattern is such that the excitation coils 25 to 27 are energized for a time sufficient for starting the motor, and the excitation time is gradually increased to reduce the rotation speed of the rotor. Try to speed it up. When the rotation speed of the rotor reaches a sufficient speed, back electromotive forces Va, Vb, and Vc are generated in the excitation coils 25 to 27 so that the rotation position of the rotor can be specified.

FIG. 2A shows the back electromotive force Va generated in the exciting coil 25 as an example of the back electromotive forces Va, Vb, and Vc. Here, the other back electromotive forces Vb and Vc are not shown, but the phases are different by 120 ° from the back electromotive force Va, but the waveforms are the same. As shown in FIG. 2A, the waveform of the back electromotive force Va has a different length between the positive period and the negative period. However, as shown in FIG. This is because the small tooth pole 7a and the small tooth pole of the rotor magnetic pole 8 are shifted from each other by a half pitch.

Each of the back electromotive forces Va to Vc is compared with the neutral point voltage of the motor 28 by three comparators (not shown) in the rotational position detecting unit 21, and the back electromotive force Va to Vc is output from each comparator. When the voltage exceeds the voltage, an output that becomes the “H” level is obtained. However,
As shown in FIG. 2A, the back electromotive forces Va to Vc
Since a spike voltage c that occurs transiently during commutation is included, the output of each comparator cannot be used as it is as a rotor position signal indicating the rotational position of the rotor. Therefore, the rotational position detector 21 eliminates the influence of the spike voltage c from the output of the comparator by using an appropriate means such as a mask. For this reason, the rotation position detection unit 2
1 output rotor position signals S1 to S3 indicating the rotational position of the rotor as shown in FIGS.

The rising and falling edges of the rotor position signals S1 to S3 correspond to the excitation coils 25 to 2
7 corresponds to a change time point at which the back electromotive force Va to Vc changes from positive to negative or from negative to positive (see FIG. 2A).

The timing determining and speed detecting section 22 includes rotor position signals S1 to S1 supplied from the rotational position detecting section 21.
3, the rotor position signals S1 to S
3, the rising and falling edges are sequentially detected,
T1, T2,... T between the detected edges.
n (see FIG. 2E), and based on the measured time, the energization switching timing signals S1 'to S3' for determining the energization switching timing (commutation timing) of the excitation coils 25 to 27. Is output. So, below,
The detailed signal processing of the timing determination and speed detection unit 22 will be described.

When a falling edge of the rotor position signal S1 is detected at time t1, a first counter (not shown) capable of counting up and down starts counting operation from time t1. The counting operation of the first counter is performed over a period T1 from time t1 to time t2 when the rising edge of the rotor position signal S3 is detected, and the counting operation ends at time t2. Note that the period T1 is equivalent to 60 electrical degrees.

Next, from the time t2, a second counter (not shown) capable of counting up and down starts a counting operation, and the counting operation of the second counter starts at the time t2 when the rotor position signal S2 falls. The operation is performed over a period T2 until the time t3 when the edge is detected, and the counting operation ends at the time t3. Note that the period T2 is equivalent to 60 electrical degrees. Here, the length of the period T1 is different from that of the period T2.
This is because the positive and negative periods of the back electromotive force Va to Vb generated in 5 to 27 differ, and this difference is reflected.

By the way, the energization switching timing (commutation timing) is shifted by an electrical angle of 30 ° with respect to the times t1, t2, t3... Which are the detection points of each edge of the rotor position signals S1 to S3. It is preferable to perform the operation at the time when the motor 28 is efficiently driven.

Therefore, at time t3, the first counter starts counting down the count value counted during period T1, and at time t4 when the count value becomes 1/2 (corresponding to 30 ° in electrical angle). To control section 2
Output to 3. Note that a hatched portion in FIG. 2F indicates a delay amount corresponding to 30 electrical degrees.

From time t3, a third counter (not shown) capable of counting up and down starts counting operation,
The counting operation of the third counter is performed over a period T3 from time t3 to time t5 when the rising edge of the rotor position signal S1 is detected, and the counting operation ends at time t5.

At time t5, the second counter starts counting down the count value counted during period T2,
At time t6 when the count value becomes 1/2 (corresponding to 30 electrical degrees), an energization switching timing signal is output. From time t5, a fourth counter (not shown) capable of counting up and down starts a counting operation.
The counting operation of the counter starts at time t5 when the rotor position signal S
The operation is performed over a period T4 until time t7 when the falling edge of No. 3 is detected, and the counting operation ends at time t7.

Similarly, in the period T5, the third counter outputs the energization switching timing signal at time t8 due to the countdown of the count value while the first counter performs the counting operation in the period T5. In parallel with the counting, the fourth counter outputs an energization switching timing signal at time t10 by counting down the count value.
Therefore, when the timing generation / speed detection unit 22 generates the energization switching timing signal in an arbitrary period, it is not the count value of the counter in the period immediately before the arbitrary period,
The count value of the counter in the period two times before is used.

The energization switching timing signal S generated and output by the timing determining and speed detecting section 22 in this manner.
1 ′ to S3 ′ are supplied to the control unit 23. Control unit 23
The transistor Q1 is used to excite the excitation coils 25 to 27 by a speed control signal from an adder 40 described later and a predetermined excitation method (for example, two-phase excitation).
, The energization switching timings (commutation timings) are determined by the energization switching timing signals S1 ′ to S3 output from the timing determination and speed detection unit 22. Done on the basis of '. Therefore, in the control unit 23, the exciting coils 25 to
Energizing signals P1 to P6 are generated such that the respective exciting currents at 27 become those shown in FIGS.

By the way, in the driving device with a motor regenerative function according to this embodiment, the timing determining and speed detecting unit 22 determines the rotation speed of the rotor in addition to generating the energization switching timing signal as described above. Since the closed loop speed control is also performed based on the obtained rotation speed, the operation of each unit related to the speed control will be described below.

In order to perform the speed control, the timing determining and speed detecting unit 22 detects the rotational speed of the rotor at each of the times t1, t2, t3,... Which is the detection time of each edge of the rotor position signals S1 to S3. Update. Therefore, the timing determination and speed detection unit 22 calculates, for example, at time t3, the average value of the counter value counted in the period T1 and the counter value counted in the period T2, and calculates the average value. The rotational speed of the rotor is obtained from the reciprocal of the value. Note that the sum of the period T1 and the period T2 corresponds to an electrical angle of 120 °, and since the physical distance corresponding to the electrical angle of 120 ° is known, the rotational speed of the rotor is obtained as described above.

Similarly, at time t5, the timing determination and speed detection unit 22 calculates the average value from the count value of the counter counted in the period T2 and the count value of the counter counted in the period T3. The rotation speed of the rotor is obtained and updated by the reciprocal of the obtained average value. Further, at time t7, the average value is obtained from the count value of the counter counted in the period T3 and the count value of the counter counted in the period T4. Asked,
The rotational speed of the rotor is obtained and updated based on the reciprocal of the obtained average value. Therefore, when calculating the rotation speed of the rotor, the respective count values of the counter are used repeatedly.

As described above, the rotation speed of the rotor obtained by the timing determination and speed detection unit 22 every electrical angle of 60 ° is one electrical angle such as the period T1 and the period T2.
Since the average speed during the period corresponding to 20 ° is determined, the back electromotive force Va generated in the exciting coils 25 to 27 is obtained.
Even if there is a difference between the positive and negative periods of .about.Vb, the required rotational speed of the rotor will be accurate.

The rotation speed of the rotor determined by the timing determination and speed detection unit 22 is supplied to an adder 40. The adder 40 generates a speed control signal (deviation signal) from the difference between the rotation speed and an external speed command, and outputs the generated speed control signal to the control unit 23. Control unit 23
Are transistors Q1-Q6 according to the speed control signal.
PWM control of the energization signals P1 to P6 supplied to the
The rotation speed of the rotor is controlled so as to reach a target value.

The drive device with the regenerative function of the motor according to this embodiment has the regenerative function as described above, and the details of the regenerative operation will be described with reference to FIGS.

First, the outline of the regenerative operation will be described.
A period during which no exciting current is supplied to each of the exciting coils 25 to 27 (for example, a period from time t4 to time t6 shown in FIGS. 2 and 3), and as shown in FIGS.
Periods a1, a2,... A of generation of spike voltage c due to commutation
n and the delay periods b1, b2,... bn in determining the power supply switching timing, the power generated in each of the excitation coils 25 to 27 is regenerated to the power supply side. Thus, electric braking is performed when the motor needs to be decelerated.

Such a regenerative operation is performed when the motor needs to be decelerated, and is performed at different timings for the three exciting coils 25 to 27. The regenerating operation for the exciting coil 25 will be described as an example. I do.

First, the timing determining and speed detecting section 22
Receives an instruction from the control unit 23 indicating that the regenerative operation is required, detects the timing at which the regenerative operation is started using the power supply switching timing signals S1 ′ to S3 ′ and the like. Periods a1 and b1 during which
, The period a1, b
1... A regenerative operation signal is generated so as to be at the middle “H” level. On the other hand, a regeneration pulse is generated from the regeneration pulse generator 50 and is constantly supplied to the control unit 23.

Assuming that the current time is immediately before time t4 as shown in FIGS. 2 and 3, since the transistor Q5 and the transistor Q2 are conducting as shown in FIG. 4A. Q5, the exciting coil 27, the exciting coil 2
5, and a current flows through the path of the transistor Q2 (see the dotted line in FIG. 4A). Then, when commutation is performed at time t4, transistor Q2 changes from the conductive state to the non-conductive state at this time, and transistor Q4 changes from the non-conductive state to the conductive state. Therefore, the transistor Q5, the exciting coil 27, the exciting coil 26, and the transistor Q5
4 flows (see the dotted line in FIG. 4B).

However, immediately after this commutation (immediately after time t4), the regenerative operation signal output from the timing determination and speed detector 22 becomes "H" level. The unit 23 includes a regeneration pulse generator 5
The regeneration pulse from 0 is supplied to the base of the transistor Q2, and the supply of the regeneration pulse is continued until time t4 '. That is, during the generation period a1 of the spike voltage c due to commutation, as shown in FIG.
The regenerative pulse from the regenerative pulse generator 50 is supplied to the base of the device, and a step-up chopper is formed.

Therefore, during the period a1, when the regeneration pulse is ON, the electric power (electric energy) generated in the exciting coil 25 passes through the transistor Q2 as shown by the solid line in FIG. 4B. Then, it is regenerated by the smoothing capacitor 31 on the power supply side. On the other hand, the pulse for regeneration is O
In the case of the FF, as shown by the solid line in FIG. 4C, the electric power generated in the exciting coil 25 is regenerated to the smoothing capacitor 31 on the power supply side via the diode D1.

Thereafter, at time t5, the regenerative operation signal output from the timing determination and speed detector 22 becomes "H" level, so that the control unit 23 outputs the regenerative pulse from the regenerative pulse generator 50. Again the transistor Q2
At the time t6.
Continued until That is, the delay period (delay time) b1 (FIGS. 2A and 2F) for determining the energization switching timing
3 (A) and FIG. 3 (A)), a regeneration pulse from the regeneration pulse generator 50 is supplied to the base of the transistor Q2 as shown in FIG. 3 (C) to form a boost chopper.

For this reason, in the delay period b1,
When the regeneration pulse is ON, as shown by the solid line in FIG. 4B, the power generated in the exciting coil 25 is regenerated to the smoothing capacitor 31 on the power supply side via the transistor Q2. On the other hand, when the regeneration pulse is OFF, the electric power generated in the exciting coil 25 is regenerated to the smoothing capacitor 31 on the power supply side via the diode D1, as shown by the solid line in FIG. You.

The regenerative control as described above is performed by the exciting coil 25
As for not only the periods a1 and b1 described above, but also FIG.
As shown in (A), the operation is also performed in the periods a2, b2,. Further, with respect to the exciting coils 26 and 27, the regenerative control is performed based on the same concept as the exciting coil 25.

As described above, in the driving device with a regenerative function of the motor according to this embodiment, each of the excitation coils 25 to
In a period during which no exciting current is supplied to the excitation coil 27, and as shown in FIG. 3, during the period a1 of generation of the spike voltage c due to commutation and the delay period b1 when determining the energization switching timing, each excitation coil 25 To 27 are regenerated to the power supply side. For this reason, even in the case of a sensorless three-phase hybrid type stepping motor or the like that detects the rotational position of the rotor based on the back electromotive force generated in the excitation coil of the motor, while ensuring detection of the rotational position of the rotor, Regenerative braking can be compatible.

Here, the switching means according to claim 3 corresponds to the transistors Q1 to Q6 in FIG. 1, the position detecting means corresponds to the rotational position detecting section 21, and the energization switching timing determining means corresponds to the timing / speed detecting. The control unit 23 and the like correspond to the energization signal generation unit and the driving unit, and the regeneration pulse generator 50 and the control unit 23 correspond to the regeneration control unit.

In the driving device with a regenerative function of the motor according to the present embodiment, the regenerative operation is performed during the generation periods a1, a2,... An of the spike voltages c due to commutation as described above. However, the regenerative operation is performed during the period in which the spike voltage c is masked when the rotational position detector 21 obtains the rotor position signals S1 to S3 as described above, rather than during the period in which the spike voltage c is generated. Is preferred in that it becomes longer.

Further, in the driving device with a motor regenerative function of this embodiment, the exciting coils 25 to 27 of the motor 28 are provided.
, The rotor position signals S1 to S3 indicating the rotational position of the rotor are generated from the back electromotive forces Va to Vb, and the edges of the rotor position signals S1 to S3 are sequentially detected to count the time between the edges. And a delay time is added based on each detection of the edge, and the excitation coils 25 to 27 are counted.
When deciding the energization timing, the delay time is obtained by using the count value counted by the counter in the period immediately before the immediately preceding count value of the counter.

Therefore, even if there is a difference in the mechanical accuracy of the rotor part of the motor and there is a difference between the positive and negative periods of the back electromotive force generated in the exciting coil of the motor, the difference is added to the delay time. Because it can be reflected, the excitation coil 25
~ 27 energization timing can be performed with high accuracy,
Thus, smooth rotation of the rotor and low noise can be realized.

Further, in the drive device with a motor regeneration function of this embodiment, at each of the times t1, t2, t3... Which is the detection time of each edge of the rotor position signals S1 to S3,
The rotation speed of the rotor is sequentially detected and updated using the count value of the counter. For example, at time t3, the average of the count values of the counters of the previous and the last two times, such as period T1 and period T2, is calculated. Used to determine the average speed.

Therefore, even if there is a difference in the mechanical accuracy of the rotor part of the motor and there is a difference between the positive and negative periods of the back electromotive force Va to Vb generated in the exciting coils 25 to 27, the required rotor Since the rotation speed has high accuracy, it is possible to prevent a decrease in the accuracy of the speed control composed of a closed loop.

Further, in the drive device with a motor regeneration function according to this embodiment, the timing determination and speed detection unit 22
Is constituted by a plurality of counters or the like. For example, the timing determination and speed detection unit 22 and the control unit 23 may be constituted by a one-chip microcomputer or a combination of a microcomputer and a counter. Needless to say, it may be configured by any means.

[0068]

As described above, according to the first to fourth aspects of the present invention, the regenerative operation for returning the electric power generated in each of the exciting coils to the power supply side is performed during the period when the exciting current is not supplied to the exciting coils. The sensorless motor detects the rotational position of the rotor based on the back electromotive force generated in the excitation coil of the motor, for example, because the detection is performed during a period of generation of a spike voltage generated when the energization of the excitation coil is switched. In this case, regenerative braking can be achieved while ensuring detection of the rotational position of the rotor.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a configuration of a drive device with a regenerative function for a motor according to an embodiment of the present invention.

FIG. 2 is a waveform chart showing an example of an operation waveform of each unit of the device.

FIG. 3 is a waveform chart showing an example of an operation waveform of each section of the inverter section during regenerative control.

FIG. 4 is an explanatory diagram illustrating the operation of each unit of the inverter unit during regenerative control.

FIG. 5 is a cross-sectional view showing a mechanical structure of a conventional stepping motor.

FIG. 6 is a plan view showing a relationship between a rotor and a stator of the stepping motor.

[Explanation of symbols]

 Q1 to Q6 Transistors D1 to D6 Diode 21 Rotational position detector 22 Timing determination and speed detector 23 Control unit 24 Inverter unit 25 to 27 Excitation coil 28 Three-phase hybrid stepping motor 29 AC power supply 30 Rectifier 31 Smoothing capacitor 40 Adder 50 pulse generator for regeneration

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Miya ▲ Saki ▼ Shinichi 3-3-5 Yamato, Suwa City, Nagano Prefecture Inside Seiko Epson Corporation (72) Inventor Akihiko Ikegami 3-3 Yamato, Suwa City, Nagano Prefecture No. 5 Seiko Epson Corporation F-term (reference) 5H560 AA10 BB04 BB07 BB12 DA13 DB13 EA02 EB01 EC03 FF01 FF04 FF13 FF14 FF23 FF28 FF57 HB02 5H580 AA05 BB09 BB10 CA03 CA12 CB03 EE02 FA03 FA04 FA03 FA04 FA03 FA04

Claims (4)

[Claims] The present invention determines a point in time at which a back electromotive force generated in an exciting coil of a motor changes from positive to negative or from negative to positive, and delays the exciting coil by applying a predetermined delay time with reference to the determined changing point. A regenerative control method for a motor that determines a switching timing and energizes the exciting coil to rotate a rotor based on the determined energizing switching timing, wherein a regenerative operation for returning power generated in the exciting coil to a power supply side. A regenerative control method for a motor, wherein the method is performed during a period in which no exciting current is supplied to the exciting coil. 2. The regenerative operation during a period in which an exciting current is not supplied to the exciting coil and at least one of a spike voltage generating period and a delay time generated when the energizing coil is switched to be energized. 2. The method according to claim 1, wherein the control is performed. 3. A switching means comprising a plurality of switching elements for sequentially energizing a plurality of exciting coils of the motor, and comparing each back electromotive force generated in the plurality of exciting coils with a predetermined voltage to determine a rotational position of the rotor. Position detecting means for generating a rotor position signal of the indicated rotor, detecting a change time point of the rotor position signal generated by the position detection means, and delaying a predetermined delay time based on the detected change time point to each of the aforementioned Energizing switching timing determining means for determining the energizing switching timing of the exciting coil; energizing signal generating means for generating an energizing signal based on the energizing switching timing determined by the energizing switching timing determining means; Driving means for driving a switching element of the switching means based on the energized signal; In a period in which no exciting current is supplied to each of the exciting coils, a regenerative control for performing a regenerative control for turning on / off a predetermined switching element of the switching elements and returning power generated in each of the exciting coils to a power supply side. And a driving device with a regenerative function for a motor, comprising: 4. The apparatus according to claim 1, wherein the regenerative control means is configured to perform at least one of a spike voltage generation period and a delay time during a period in which an excitation current is not supplied to each of the excitation coils. In one period,
The drive device with a regenerative function for a motor according to claim 3, wherein the regenerative control is performed.