JP2003299394A - Stepping motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure the stabilized continuous control of the rotation of a magnet rotor even when a stepping motor is switched between a conducting state and an interrupted state. <P>SOLUTION: An exciting phase is stored in a memory (12) when the conduction of a stepping motor (40) is interrupted. At the time of resuming the conduction of the stepping motor (40), a CPU (11) delivers a control signal to a pulse generator (13) in order to request the generation of an exciting pulse based on an exciting phase read out from the memory (12). Based on the control signal, the pulse generator (13) generates an exciting pulse signal which is delivered to a power amplifying section (22). The power amplifying section (22) performs the power amplification of the exciting pulse signal and feeds an exciting current to the exciting coil of the stepping motor (40). A magnet rotor located at a nonexcited stable angular position can thereby be reset to the angular position at the time of interrupting conduction. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor control device and, more particularly, to a technique for controlling an angular position of a magnet rotor when a stepping motor having a magnet rotor is turned on / off and restarted.

[0002]

2. Description of the Related Art A stepping motor is capable of controlling the rotational speed of a rotor and accurate positioning control by open loop control, and is used for rotating or linearly moving a driven member. In the stepping motor, by supplying the exciting current to the exciting coil wound around the stator core,
By changing the excitation state of the exciting coil, the rotor can be accurately angularly displaced (rotationally displaced) in units of a constant angle (step angle).

FIG. 9 is a block diagram of a drive control circuit of a stepping motor. As shown in the figure, the drive control circuit of the stepping motor includes a pulse generator 31, a frequency changing unit 32, a controller 14, a power amplifying unit 23, and a stepping motor 41. The pulse generator 31 outputs a pulse signal having a constant cycle to the controller 14. The frequency changing unit 32 is configured to change the clock frequency of the pulse generator 31, and adjusts the rotation speed of the rotor 61 of the stepping motor 41.

The controller 14 is a CPU (Central Proc
ESSING UNIT), a dedicated IC chip including a memory, and the like, and includes a mode switching unit 15, an excitation phase control unit 16, a rotation direction switching unit 17, and a start / stop circuit 18. The mode switching unit 15 has a function of switching the excitation sequence of the stepping motor 41, and switches 1-phase excitation, 2-phase excitation, and 1-2-phase excitation as needed. The excitation phase control unit 16 follows the excitation sequence designated by the mode switching unit 15 and the excitation coil 77 of the stepping motor 41.
Determines the excitation order of the phase excitation pulse signals and outputs the phase excitation pulse signal to the power amplifier 2
Output to 3.

The power amplification unit 23 power-amplifies the phase excitation pulse signal supplied from the excitation phase control unit 16, and the excitation coil 7
An exciting current is supplied to 7. The stepping motor 41 is composed of a rotor 61 coupled to a rotating shaft and an exciting coil 77 wound around a stator. An exciting current supplied to the exciting coil 77 changes the exciting state of the exciting coil 77.
The rotor 61 is angularly displaced in step angle units. The rotation direction switching unit 17 has a function of changing the rotation direction of the rotor 61 of the stepping motor 41, and switches the rotation direction of the rotor 61 to the forward rotation direction or the reverse rotation direction. The start / stop circuit 18 controls ON / OFF of the operation of the stepping motor 41.

[0006]

By the way, in the above configuration, assuming that the stepping motor 41 is a hybrid type, the number of gear-shaped salient poles formed on the outer periphery of the rotor 61 is 50 1 of 61
When the number of rotation steps is 200, the step angle is 1.8 °. In the hybrid type stepping motor, the rotor 61 is composed of a permanent magnet. Therefore, when the power of the controller 14 is turned off and the supply of the exciting current to the exciting coil 77 is cut off, the rotor 61 is formed on the outer peripheral surface thereof. The angle at which the magnetic resistance of the magnetic circuit formed between the gear-shaped salient poles and the pole teeth of the stator becomes the smallest,
That is, it is angularly displaced to the non-excitation stable angle and is held in that state.

When the number of gear-shaped salient poles formed on the outer circumference of the rotor 61 is 50, the non-excitation stable angle is 360 ° / 50.
= Every 7.2 °. Therefore, when the exciting current supplied to the exciting coil 77 is cut off, the rotor 61 moves to ± 3.6.
It is angularly displaced in the range of ° and is maintained in a stable state. In order to rotate the rotor 61 in this state, an external force equal to or larger than the non-excitation holding torque is required.

In this way, the controller 14 is turned on.
When it is set to FF, the rotor 61 is angularly displaced to the non-excitation stable angle and is held in a stable state.
Even if an attempt is made to control the rotation of the rotor 61 according to a predetermined excitation sequence after turning on the power source, the accurate positioning control cannot be performed, and it is difficult to continuously control the rotation of the rotor 61 before and after the power is turned on / off. Become.

Such a problem is not limited to a hybrid type stepping motor as long as it is a stepping motor having a magnet rotor, and a PM type (Permanent Magnet T
ype) stepping motor also occurs.

Therefore, the present invention provides a stepping motor control device that enables stable and continuous rotation control of the magnet rotor even when the stepping motor is switched between the energized state and the de-energized state. This is an issue.

[0011]

In order to solve the above-mentioned problems, the stepping motor control device of the present invention has a memory circuit for storing the excitation phase at the time when the power supply to the stepping motor is cut off, and the power supply to the stepping motor. When resuming, a pulse generator that generates an excitation pulse signal based on the excitation phase read from the memory circuit, and the excitation pulse signal output from the pulse generator is power-amplified,
And a drive circuit for returning the magnet rotor at the non-excitation stable angular position to the angular position when the energization is cut off by supplying an exciting current to the exciting coil.

With the above structure, the excitation phase at the time when the energization to the stepping motor is cut off is stored in the memory circuit, so that the angular position of the magnet rotor when the energization is restarted is cut off from the non-excitation stable angular position. Can be returned to the angular position of.

A stepping motor control device according to another aspect of the present invention is an encoder which is connected to a shaft end of a magnet rotor to detect an angular position of the magnet rotor and an angular position of the magnet rotor when power to the stepping motor is cut off. And a pulse generator that generates an excitation pulse signal based on the angular position read from the storage circuit when resuming energization to the stepping motor, and an excitation pulse output from the pulse generator. A drive circuit is provided, which amplifies the power of the signal and supplies an exciting current to the exciting coil to restore the magnet rotor in the non-excitation stable angular position to the angular position when the energization is cut off.

With the above configuration, the angular position of the magnet rotor at the time when the power supply to the stepping motor is cut off is stored in the memory circuit, so that the angular position of the magnet rotor when the power supply is restarted is changed from the non-excitation stable angular position. It is possible to return to the angular position when the power supply is cut off.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 of the Invention Below, Figure 1
The first embodiment will be described with reference to FIGS.

FIG. 1 is a block diagram of a stepping motor controller. As shown in the figure, the drive control system of the stepping motor includes a controller 10, a driver 20, a commercial power supply 30, and a stepping motor 40. The controller 10 includes a CPU 11, a memory 12, and a pulse generator 13.

The CPU 11 outputs various control signals for instructing the rotation direction, rotation speed, phase switching, etc. of the stepping motor 40 to the pulse generator 13 according to a predetermined excitation sequence. The pulse generator 13 generates a phase excitation pulse signal based on the control signal output from the CPU 11,
This is output to the power amplification unit 22. Driver 20 is DC
A power supply 21 and a power amplifier 22 are provided. The DC power supply 21 is composed of an AC / DC converter, converts the AC voltage supplied from the commercial power supply 30 into a DC voltage, and supplies the DC voltage to the power amplification unit 22.

The power amplifier 22 power-amplifies the excitation pulse signal output from the pulse generator 13 to a voltage required to drive the stepping motor 40, and supplies an exciting current to the exciting coil of the stepping motor 40. In the stepping motor 40, the exciting state of the exciting coil is changed by the exciting current supplied from the power amplifying unit 22, and the CPU 11
The rotor is angularly displaced in step angle units in the rotation direction and rotation speed specified by. In this embodiment, the stepping motor 40 is a PM type or a hybrid type, and the rotor is composed of a permanent magnet.

In the above-mentioned structure, the angle control of the magnet rotor when the stepping motor 40 is switched from the energized state to the energized cut-off state and then re-energized to return the stepping motor 40 to the excited state is described with reference to FIG. explain. The stepping motor 40 is shown in the upper part of the figure.
An excitation sequence in the case of driving the motor with two-phase excitation is shown. The exciting coil is of unipolar type,
The excitation order of the phase, RA phase (opposite phase of A phase), B phase, and RB phase (opposite phase of B phase) is shown.

In the following description, the number of gear-shaped salient poles formed on the outer periphery of the magnet rotor of the stepping motor 40 is 50 and the step angle is 1.8 °, but the present invention is not limited to this. No, it can be applied at other step angles (eg, step angle 3.6 °), and
The excitation sequence is not limited to the two-phase excitation method, and may be the one-phase excitation method, the one-two phase excitation method, or the microstep excitation method. Further, in the figure, 0 ° indicates the angular position of the non-excitation stable angle of the magnet rotor, and the magnet rotor is graduated in + 1.8 ° units in the forward rotation direction and in -1.8 ° units in the reverse rotation direction. There is. In this example, the non-excitation stable angle is RA
There is an OFF set of Δθ in the reverse direction with respect to the angular position corresponding to the center of the section where both the phase and the RB phase are at the H level.

When the magnet rotor is at an angle position of -3.6 ° with respect to the non-excitation stable angle, when the CPU 11 detects an input signal of power OFF (step S11),
The CPU 11 reads the excitation phase from the pulse generator 13 and stores it in the memory 12 (step S12).
In this example, as described above, the non-excitation stable angles are RA phase and R phase.
Since there is an OFF set of Δθ in the reverse rotation direction with respect to the angular position corresponding to the center of the section where both B phases are at H level,
Magnet rotor is -3.6 °, -1.8 °, +1.8.
When the power is turned off at the angular position of °, the magnet rotor is angularly displaced to the position of 0 ° which is the non-excitation stable angular position, but when it is at the position of + 3.6 °, other non-excited magnets are not excited. It is angularly displaced to a stable angular position.

Therefore, when the power is turned off when the magnet rotor is at the position of -3.6 °, -3.6
Excitation phase (A phase-H, B phase-
H) and the excitation phase (R
(A-phase-H, B-phase-H) is read and stored in the memory 12. Next, the CPU 11 supplies the DC power source 21 with the power source O.
The FF signal is output, and the DC voltage supplied from the DC power supply 21 to the power amplification unit 22 is cut off. As a result, the power supply to the stepping motor 40 is cut off (step S13). Then, the stepping motor 40 is angularly displaced to the non-excitation state, and the magnet rotor is angularly displaced to the non-excitation stable angular position to be in the stable state (step S14).

When the CPU 11 detects the power-on input signal in this state (step S15), the CPU 11 first outputs the power-on signal to the DC power source 21 to restart the supply of the DC voltage from the DC power source 21 to the power amplification section 22. At the same time, the excitation phase stored in the memory 12 is read out,
The RA phase is excited to the H level and the B phase is excited to the H level to angularly displace the magnet rotor to an angular position of -1.8 ° (step S16). Then, the A phase is excited to the H level and the B phase is excited to the H level to angularly displace the magnet rotor to an angular position of -3.6 ° (step S17). This allows
The magnet rotor is at the position immediately before the power is turned off.-3.
It returns to the angular position of 6 ° (step S18).

With the above configuration, the CPU 11 causes the power supply OF to be turned off.
As a result of detecting the F input and shutting off the exciting current supplied to the stepping motor 40, even when the magnet rotor is angularly displaced to a non-excitation stable state, the magnet rotor returns to the angular position immediately before the power is turned off when the power is turned on. Therefore, it is possible to continuously control the rotation of the magnet rotor before and after the power is turned on / off.

In the above description, the magnet rotor is-
When the power is turned off at the angular position of 3.6 °, the power is turned off at the angular position of −1.8 °.
When F is set, the excitation information (RA phase-H, B phase-H) of RA phase and B phase may be stored in the memory 12, and +1.8.
When the power is turned off at the angular position of °, the excitation information (A phase-H, RB phase-) of the A phase and the RB phase is stored in the memory 12.
H) should be stored.

In the above description, the non-excitation stable angle is R
In the case where there is an OFF set of Δθ in the reverse rotation direction with respect to the angular position corresponding to the center of the section where both the A phase and the RB phase are at the H level, when there is an OFF set of Δθ in the forward rotation direction, Magnet rotor is -1.8 °, +1.8
When the power is turned off at the angular positions of ° and + 3.6 °, the magnet rotor is at the non-excitation stable angular position of 0.
When it is in the angular position of -3.6 ° and is in the angular position of -3.6 °, it is angularly displaced in another non-excitation stable angular position (not shown).

Next, referring to FIG. 3, the OFF set Δθ
An example in which is 0 will be described. Since Δθ is 0 in this example, it is unknown whether the magnet rotor is angularly displaced to the non-excitation stable angular position in the figure or to another (not shown) non-excitation stable angular position in the non-excitation state. Is. Therefore, in the present embodiment, when the CPU 11 detects that the power is off, the magnet rotor is forcibly angularly displaced to any non-excitation stable angular position. In this example, a case will be described where the angular position is changed from -3.6 ° to -1.8 ° and then to 0 ° (non-excitation stable angular position).

When the magnet rotor is at an angular position of -3.6 ° with respect to the non-excitation stable angle, when the CPU 11 detects an input signal of power OFF (step S21),
The CPU 11 reads the excitation phase from the pulse generator 13 and stores it in the memory 12 (step S22).
As a result, the memory 12 stores the excitation phases (A phase-H, B phase-H) corresponding to the angular position of -3.6 °.
Next, the CPU 11 outputs a control signal to the pulse generator 13 to excite the RA-phase exciting coil and the B-phase exciting coil in order to angularly displace the magnet rotor to an angular position of −1.8 °. Phase B and phase B are excited (step S23). As a result, the magnet rotor is -1.8.
It is angularly displaced to an angular position of °. The CPU 11 stores the excitation phase (RA phase-H, B phase-H) in this state in the memory 12.

Next, the CPU 11 outputs a power OFF signal to the DC power source 21, and the DC power source 21 causes the power amplifying section 22.
Cut off the supply of DC voltage to the. This allows
The power supply to the stepping motor 40 is cut off (step S24). Then, the stepping motor 40 is angularly displaced to the non-excitation state, and the magnet rotor is angularly displaced to the non-excitation stable angular position to be in the stable state (step S2).
5).

When the CPU 11 detects an input signal of power ON in this state (step S26), the CPU 11 first outputs a power ON signal to the DC power source 21 to restart the supply of the DC voltage from the DC power source 21 to the power amplification section 22. At the same time, the excitation phase stored in the memory 12 is read out,
The RA phase is excited to the H level and the B phase is excited to the H level to angularly displace the magnet rotor to an angular position of -1.8 ° (step S27). Then, the A phase is excited to the H level and the B phase is excited to the H level to angularly displace the magnet rotor to an angular position of -3.6 ° (step S28). This allows
The magnet rotor is at the position immediately before the power is turned off.-3.
It returns to the angular position of 6 ° (step S29).

With the above construction, when the angular position of the magnet rotor is ± 3.6 ° when Δθ is 0, it is unknown which non-excitation stable angular position the magnet rotor is angularly displaced. However, by forcibly displacing the magnet to any non-excitation stable angular position, the magnet rotor can be returned to the angular position immediately before the power is turned off when the power is turned on.

In the above description, the case where the magnet rotor is angularly displaced in the forward rotation direction in order to forcibly angularly displace the magnet rotor to the non-excitation stable angular position has been described, but the magnet rotor is forcibly displaced. It is also possible to perform angular displacement in the reverse direction to perform angular displacement to another non-excitation stable angular position (not shown). Further, when the angular position of the magnet rotor when the power is off is ± 1.8 °, the non-excitation stable angular position at which the magnet rotor is angularly displaced is uniquely determined. Therefore, the magnet rotor is forcibly forced by the above method. It is not necessary to perform angular displacement to the non-excitation stable angular position. Embodiment 2 of the invention. Next, a second embodiment will be described with reference to FIGS. 4 to 6.

FIG. 4 is a block diagram of the stepping motor controller. As shown in the figure, the drive control system of the stepping motor comprises a controller 10, a driver 20, a commercial power supply 30, stepping motors 40A to 40C, and a switching circuit 50. In the present embodiment, three stepping motors 40A to 40C connected in parallel are provided, and any one of the stepping motors is selected and drive control is possible. The specific configurations of the controller 10, the driver 20, and the commercial power supply 30 are the same as those in the first embodiment.

Further, stepping motors 40A to 40C
The angle control of the magnet rotor when the stepping motors 40A to 40C are returned to the energized state by switching the energized state from the energized state to the energized state again, is the same as in the first embodiment. The memory 12 stores the excitation phases of the stepping motors 40A to 40C when the energization is cut off.

The switching circuit 50 comprises switching elements 50A to 50C for supplying an exciting current to each of the stepping motors 40A to 40C. For example, when driving the stepping motor 40B, the CPU 11 outputs a switching control signal to the switching circuit 50 and turns on the switching element 50B. As a result, the power amplification unit 22 power-amplifies the excitation pulse signal output from the pulse generator 13, and can supply the excitation current to the stepping motor 50B via the switching element 50B. Stepping motor 40
Similarly for A and 40C, switching elements 50A,
Drive control is possible by turning ON 50C.

Specific circuit configurations of the stepping motors 40A to 40C and the switching elements 50A to 50C will be described with reference to FIGS. FIG. 5 is a circuit configuration diagram in the case of the unipolar drive system. In the figure, the stepping motor 40A includes a magnet rotor 60A and exciting coils 71A to 74A. A center tap is connected between the exciting coils 71A and 72A, and the switching element 81A switches the supply of the exciting current. Similarly, a center tap is connected between the exciting coils 73A and 74A, and the switching element 82A switches the supply of the exciting current. The switching elements 81A and 82A are, for example, transistor elements and constitute the switching element 50A.

In the above structure, the switching element 8
By turning ON 1A and supplying the exciting current to the exciting coil 71A, the A phase becomes the H level, and by supplying the exciting current to the exciting coil 72A, the RA phase becomes the H level. On the other hand, the switching element 82A is turned on to turn on the excitation coil 7
By supplying the exciting current to 3A, the phase B becomes H level, and by supplying the exciting current to the exciting coil 74A, RB
The phase becomes H level.

The stepping motors 40B and 40C have the same circuit structure, and the stepping motor 40B is composed of a magnet rotor 60B and exciting coils 71B to 74B. The stepping motor 40C also includes a magnet rotor 60C and exciting coils 71C to 74C. The switching element 50B is composed of switching elements 81B and 82B, and the switching element 50C is composed of switching elements 81C and 82C.

Next, with reference to FIG. 6, the circuit configuration in the case of the bipolar drive system will be described. In the figure, the stepping motor 40A includes a magnet rotor 60A and exciting coils 75A and 76A. A switching element 81A switches the supply of the exciting current to the exciting coil 75A. Similarly, the switching of the exciting current to the exciting coil 76A is switched by the switching element 82A. The switching elements 81A and 82A are, for example, transistor elements, and the switching element 50
It constitutes A.

In the above structure, the switching element 8
By turning ON 1A and changing the direction of the exciting current supplied to the exciting coil 75A, the excited state of the phase A can be switched. Similarly, the B-phase excitation state can be switched by turning on the switching element 82A and changing the direction of the excitation current supplied to the excitation coil 76A. The stepping motors 40B and 40C have the same circuit configuration, and the stepping motor 40B includes a magnet rotor 60B and exciting coils 75B and 76B. The stepping motor 40C also includes a magnet rotor 60C and exciting coils 75C and 76C. The switching element 50B is composed of switching elements 81B and 82B, and the switching element 50C is composed of switching elements 81C and 82C.

In this embodiment, the case where any one of the three stepping motors 40A to 40C is selected for drive control has been described, but the number of stepping motors is not limited to three, and Any number can be used. Embodiment 3 of the invention. Next, a third embodiment will be described with reference to FIG. This embodiment is a modification of the second embodiment. In the second embodiment, any one of the three stepping motors 40A to 40C is selected for drive control, but in the present embodiment, the stepping motors can be drive-controlled for any combination.

For example, the operation of only the stepping motor 40A, the operation of only the stepping motor 40B, the operation of only the stepping motor 40C, and the stepping motor 40
Parallel operation of A and 40C, stepping motors 40B and 4
0C parallel operation, all stepping motors 40A-4
Drive control can be performed by selecting an arbitrary combination from the three stepping motors 40A to 40C, such as 0C parallel operation, ....

Therefore, the CPU 11 supplies an exciting current switching signal to the power amplifying unit 22 in order to supply the exciting current corresponding to the number of driven stepping motors from the power amplifying unit 22 to each stepping motor. When the number of driving stepping motors is one, the power amplifier 22 which receives the excitation current switching signal supplies 1/3 of the exciting current to the stepping motor when the number of driving stepping motors is three, and the stepping motor is driven. When the number of driven vehicles is 2, the exciting current of 2/3 is supplied to the stepping motor when the number of driven vehicles is 3.

Regarding the angle control of the magnet rotor when the stepping motors 40A to 40C are switched from the energized state to the de-energized state and then re-energized to return the stepping motors 40A to 40C to the excited state, the first embodiment is performed. It is the same as the form. The memory 12 stores the excitation phases of the stepping motors 40A to 40C when the energization is cut off. Further, in the present embodiment,
The case where drive control is performed for any arbitrary combination of the three stepping motors 40A to 40C has been described, but the number of stepping motors is not limited to three, and any number can be used. Fourth Embodiment of the Invention Next, a fourth embodiment will be described with reference to FIG. This embodiment is a modification of the first embodiment, and differs from the first embodiment in that the deviation counter 14 and the rotary encoder 90 are provided.
The deviation counter 14 and the rotary encoder 90 switch the stepping motor 40 from the energized state to the de-energized state and then re-energize the stepping motor 40.
It plays a role of correcting the angle control error of the magnet rotor when 0 is returned to the excited state.

The angle control of the magnet rotor in this embodiment will be described. Since the basic control method is the same as that of the first embodiment, the different points will be mainly described.
When the CPU 11 detects the power OFF input and the excitation current supplied to the stepping motor 40 is cut off, C
PU11 reads the excitation phase from the pulse generator 13,
This is stored in the memory 12. Rotary encoder 9
0 is connected to the shaft end of the magnet rotor, detects the rotation angle of the magnet rotor, and outputs the angular position of the magnet rotor to the deviation counter 14 before and after the interruption of energization. When the CPU 11 detects the power ON input again, the CP
U11 reads the excitation phase stored in the memory 12 and outputs a control signal requesting the generation of an excitation pulse signal based on the excitation phase to the deviation counter 14.

The deviation counter 14 compares the excitation phase included in the control signal output from the CPU 11 with the angular position of the magnet rotor detected by the rotary encoder 90, and an angular deviation occurs between the excitation phase and the angular position. In this case, the control signal for requesting the generation of the excitation pulse signal is output to the pulse generator 13 based on the angular position of the magnet rotor detected by the rotary encoder 90. On the other hand, when there is no angular deviation between the excitation phase and the angular position, the deviation counter 14 outputs to the pulse generator 13 a control signal requesting the generation of an excitation pulse signal based on the excitation phase. The power amplification unit 22 power-amplifies the excitation pulse signal output from the pulse generator 13 and supplies an excitation current to the stepping motor 40.

As described above, according to this embodiment, even if an error occurs in the angle control of the magnet rotor based on the excitation phase, the error is corrected based on the angular position of the magnet rotor detected by the rotary encoder 90. can do.

In the present embodiment, the configuration has been described in which the angle control error of the magnet rotor based on the excitation phase is corrected based on the angular position of the magnet rotor detected by the rotary encoder 90, but the rotary encoder 90 detects it. Memory 1 for the angular position of the magnet rotor
2 may be stored and the angle of the magnet rotor may be controlled based on the angular position. By performing the angle control of the magnet rotor based on the angular position, there is a problem in the case of the offset Δθ = 0 described in the first embodiment (the angular position of the magnet rotor is ± 3.6 °.
In this case, it is possible to omit a complicated control procedure such as forcibly performing the angular displacement to any non-excitation stable angle in order to resolve which unexcited stable angle is angularly displaced).

Further, as in the second or third embodiment, a plurality of stepping motors are connected in parallel,
An arbitrary stepping motor may be selected from the stepping motors to drive and control it.

[0050]

According to the present invention, by storing the excitation phase or the angular position of the magnet rotor in the memory circuit at the time when the power supply to the stepping motor is cut off, the angular position of the magnet rotor when the power supply is restarted can be eliminated. It is possible to return from the excitation stable angular position to the angular position when the power supply is cut off.

[Brief description of drawings]

FIG. 1 is a block diagram of a stepping motor control device of the present invention.

FIG. 2 is an explanatory diagram of angle control of a magnet rotor.

FIG. 3 is an explanatory diagram of angle control of a magnet rotor.

FIG. 4 is a block diagram of a stepping motor control device of the present invention.

FIG. 5 is a circuit diagram of a stepping motor.

FIG. 6 is a circuit diagram of a stepping motor.

FIG. 7 is a block diagram of a stepping motor control device of the present invention.

FIG. 8 is a block diagram of a stepping motor control device of the present invention.

FIG. 9 is a block diagram of a conventional stepping motor control device.

[Explanation of symbols]

10 ... Controller, 11 ... CPU, 12 ... Memory, 1
3 ... Pulse generator, 14 ... Deviation counter, 20 ... Driver, 21 ... DC power supply section, 22 ... Power amplification section, 30 ... Commercial power supply, 40 ... Stepping motor, 50 ... Switching circuit, 90 ... Rotary encoder

Claims (5)

[Claims] 1. A storage circuit that stores an excitation phase at the time when the power supply to the stepping motor is cut off, and an excitation pulse signal based on the excitation phase read from the storage circuit when the power supply to the stepping motor is restarted. The pulse generator to generate and the excitation pulse signal output from the pulse generator are power-amplified, and the exciting current is supplied to the exciting coil to supply the exciting current to the exciting coil. And a drive circuit for returning to the stepping motor control device. 2. An encoder connected to the shaft end of the magnet rotor to detect the angular position of the magnet rotor at the time when the power supply to the stepping motor is cut off, and the angular position output by the encoder and stored in the storage circuit. And a deviation counter that instructs the pulse generator to generate an excitation pulse signal based on the angular position when an angular deviation is generated between the two excitation phases. The stepping motor control device described. 3. An encoder connected to a shaft end of a magnet rotor to detect its angular position, a memory circuit for storing the angular position of the magnet rotor when the energization to the stepping motor is cut off, and an energization to the stepping motor. When resuming, the pulse generator that generates the excitation pulse signal based on the angular position read from the storage circuit, the excitation pulse signal output from the pulse generator is power-amplified, and the excitation current is supplied to the excitation coil. A stepping motor control device, comprising: a drive circuit that supplies the magnet rotor to a non-excitation stable angular position to return to an angular position when power is cut off. 4. A switching circuit for selecting any one stepping motor from a plurality of stepping motors connected in parallel and for supplying an exciting current output from the drive circuit. 3. The stepping motor control device according to any one of 3. 5. A stepping motor is selected for an arbitrary combination from a plurality of stepping motors connected in parallel, and a switching circuit that supplies an exciting current output from the drive circuit and an output from the drive circuit. 4. The stepping motor control device according to claim 1, further comprising an exciting current switching unit that switches the magnitude of the exciting current to the number of selected stepping motors.