阅读说明：本技术 步进马达控制装置、钟表和步进马达控制方法 (Stepping motor control device, timepiece, and stepping motor control method ) 是由 奥村朗人 山本幸祐 小笠原健治 井桥朋宽 于 2020-09-24 设计创作，主要内容包括：本发明进行能量效率好的步进马达控制。步进马达控制装置通过施加通常驱动脉冲或具有比前述通常驱动脉冲更大的能量的固定脉冲,从而使步进马达驱动。该步进马达控制装置具备：判定部,其基于在前述通常驱动脉冲之前施加至前述步进马达的脉冲是否为前述固定脉冲,判定是否将消磁脉冲附加至前述通常驱动脉冲,该消磁脉冲抵消在施加前述固定脉冲时产生于前述步进马达的定子中的残留磁通；和驱动控制部,其基于前述判定部所判定的结果,通过附加了前述消磁脉冲的前述通常驱动脉冲来驱动前述步进马达。(The invention performs stepping motor control with good energy efficiency. The stepping motor control means drives the stepping motor by applying a normal drive pulse or a fixed pulse having a larger energy than the aforementioned normal drive pulse. The stepping motor control device is provided with: a determination unit that determines whether or not a degaussing pulse that cancels a residual magnetic flux generated in a stator of the stepping motor when the fixed pulse is applied is added to the normal drive pulse, based on whether or not a pulse applied to the stepping motor before the normal drive pulse is the fixed pulse; and a drive control unit that drives the stepping motor by the normal drive pulse to which the degaussing pulse is added, based on a result determined by the determination unit.)

1. A stepping motor control device for driving a stepping motor by applying a normal drive pulse or a fixed pulse having a larger energy than the normal drive pulse, the stepping motor comprising a stator provided with a rotor through hole, a rotor rotatably disposed in the rotor through hole, and a coil provided in the stator,

the stepping motor control device is provided with:

a determination unit that determines whether or not a degaussing pulse that cancels a residual magnetic flux generated in the stator when the fixed pulse is applied is added to the normal drive pulse, based on whether or not a pulse applied to the stepping motor before the normal drive pulse is the fixed pulse; and

and a drive control unit that drives the stepping motor by the normal drive pulse to which the degaussing pulse is added, based on a determination result of the determination unit.

2. The stepping motor control device according to claim 1, wherein when the determination unit determines that the pulse applied to the stepping motor before the normal drive pulse is the fixed pulse, the drive control unit drives the stepping motor by the normal drive pulse to which the demagnetization pulse is added.

3. The stepping motor control device according to claim 1 or 2, wherein an on time in one period of the fixed pulse is longer than an on time of the normal drive pulse.

4. The stepping motor control device according to any one of claims 1 to 3, wherein a period of the normal drive pulse for moving the hand by a predetermined angle is made to coincide with a period of the fixed pulse.

5. The stepping motor control device according to any one of claims 1 to 3, wherein a period of the fixed pulse is shorter than a period of the normal driving pulse.

6. The stepping motor control device according to any one of claims 1 to 5,

further comprising a calculation unit for determining the energy of the degaussing pulse based on the energy of the fixed pulse applied before the normal drive pulse,

the drive control unit adds the degaussing pulse having the energy determined by the calculation unit to the next normal drive pulse to which the fixed pulse is applied.

7. The stepping motor control device according to claim 6, wherein the arithmetic unit adds the degaussing pulse based on the energy of the fixed pulse applied before the normal drive pulse to the normal drive pulse, and further adds a second degaussing pulse having a smaller energy than the degaussing pulse to a next normal drive pulse.

8. The stepping motor control device according to claim 6 or 7, wherein the arithmetic unit determines the voltage value of the degaussing pulse based on an energy of the fixed pulse applied before the normal drive pulse.

9. A stepping motor control device for driving a stepping motor by applying a normal drive pulse or a fixed pulse having a larger energy than the normal drive pulse, the stepping motor comprising a stator provided with a rotor through hole, a rotor rotatably disposed in the rotor through hole, and a coil provided in the stator,

the stepping motor control device is provided with:

a drive voltage determination unit that determines a voltage of the normal drive pulse based on whether or not a pulse applied to the stepping motor before the normal drive pulse is the fixed pulse; and

and a drive control unit that drives the stepping motor by the normal drive pulse based on a determination result of the drive voltage determination unit.

10. A timepiece provided with the stepping motor control device according to any one of claims 1 to 9.

11. A stepping motor control method for driving a stepping motor by applying a normal drive pulse or a fixed pulse having a larger energy than the normal drive pulse, the stepping motor including a stator provided with a rotor through hole, a rotor rotatably disposed in the rotor through hole, and a coil provided in the stator,

the stepping motor control method comprises the following steps:

determining whether to add a degaussing pulse to the normal drive pulse based on whether a pulse applied to the stepping motor before the normal drive pulse is the fixed pulse, the degaussing pulse canceling a residual magnetic flux generated in the stator when the fixed pulse is applied,

the stepping motor is driven by the normal drive pulse to which the degaussing pulse is added based on a determination result of the determination unit.

Technical Field

Embodiments of the invention relate to a stepping motor control device, a timepiece, and a stepping motor control method.

Background

Conventionally, there are techniques for controlling a stepping motor used for driving hands of a timepiece or the like, such as: by detecting the induced voltage after the rotation of the rotor, it is detected that the rotor does not rotate regardless of whether or not energy is applied to the stepping motor. In the related art, when it is detected that the rotor does not rotate, a correction drive pulse is further applied to the stepping motor to perform the needle passing. However, in the subsequent needle passing by the correction drive pulse, a part of the energy applied is consumed to demagnetize the residual magnetic force caused by the application of the correction drive pulse. Therefore, there is a problem that energy that can be used for needle travel is reduced.

In order to solve such a problem, the following techniques are known: the energy applied to the stepping motor after the correction drive is made larger than the energy applied to the stepping motor in the case where the correction drive is not performed (for example, see patent document 1).

Prior art documents

Patent document

Patent document 1: japanese patent laid-open No. 2006 and 226927.

Disclosure of Invention

Problems to be solved by the invention

Since the energy of the correction drive pulse is large, according to the conventional technique described in patent document 1, it is necessary to apply a larger energy to demagnetize the residual magnetic force generated by the correction drive pulse. Therefore, the conventional technique as described in patent document 1 wastes energy. That is, the control method of the stepping motor according to the related art has a problem of poor energy efficiency.

The embodiments of the present invention have been made in view of such circumstances, and an object thereof is to provide a stepping motor control device, a timepiece, and a stepping motor control method which are excellent in energy efficiency.

Means for solving the problems

A stepping motor control device according to an aspect of the present invention drives a stepping motor by applying a normal drive pulse or a fixed pulse having energy larger than the normal drive pulse, and includes a stator having a rotor through hole, a rotor rotatably disposed in the rotor through hole, and a coil provided in the stator. The stepping motor control device is provided with: a determination unit that determines whether or not a degaussing pulse that cancels a residual magnetic flux generated in the stator when the fixed pulse is applied is added to the normal drive pulse, based on whether or not a pulse applied to the stepping motor before the normal drive pulse is the fixed pulse; and a drive control unit that drives the stepping motor by the normal drive pulse to which the degaussing pulse is added, based on a determination result of the determination unit.

In the stepping motor control device according to one aspect of the present invention, when the determination unit determines that the pulse applied to the stepping motor before the normal drive pulse is the fixed pulse, the drive control unit drives the stepping motor by the normal drive pulse to which the demagnetization pulse is added.

In the stepping motor control device according to one aspect of the present invention, the on time in one period of the fixed pulse is longer than the on time of the normal drive pulse.

In the stepping motor control device according to one aspect of the present invention, the period of the normal drive pulse for moving the hand by a predetermined angle is made to coincide with the period of the fixed pulse.

In the stepping motor control device according to one aspect of the present invention, the period of the fixed pulse is shorter than the period of the normal drive pulse.

The stepping motor control device according to one aspect of the present invention further includes a calculation unit that determines the energy of the degaussing pulse based on the energy of the fixed pulse applied before the normal drive pulse, and the drive control unit adds the degaussing pulse having the energy determined by the calculation unit to the next normal drive pulse to which the fixed pulse is applied.

In the stepping motor control device according to one aspect of the present invention, the calculation unit adds the degaussing pulse having an energy based on the energy of the fixed pulse applied before the normal drive pulse to the normal drive pulse, and further adds a second degaussing pulse having an energy smaller than that of the degaussing pulse to the next normal drive pulse.

In the stepping motor control device according to one aspect of the present invention, the calculation unit determines the voltage value of the degaussing pulse based on the energy of the fixed pulse applied before the normal drive pulse.

A stepping motor control device according to an aspect of the present invention drives a stepping motor by applying a normal drive pulse or a fixed pulse having energy larger than the normal drive pulse, the stepping motor including a stator having a rotor through hole, a rotor rotatably disposed in the rotor through hole, and a coil provided in the stator. The stepping motor control device is provided with: a drive voltage determination unit that determines a voltage of the normal drive pulse based on whether or not a pulse applied to the stepping motor before the normal drive pulse is the fixed pulse; and a drive control unit that drives the stepping motor by the normal drive pulse based on a determination result of the drive voltage determination unit.

A timepiece according to an aspect of the present invention includes the stepping motor control device.

A stepping motor control method according to an aspect of the present invention is a stepping motor control method for driving a stepping motor by applying a normal drive pulse or a fixed pulse having energy larger than the normal drive pulse, the stepping motor including a stator having a rotor through hole, a rotor rotatably disposed in the rotor through hole, and a coil provided in the stator. The stepping motor control method determines whether or not a degaussing pulse that cancels a residual magnetic flux generated in the stator when the constant pulse is applied is added to the normal drive pulse based on whether or not a pulse applied to the stepping motor before the normal drive pulse is the constant pulse, and drives the stepping motor by the normal drive pulse to which the degaussing pulse is added based on a determination result of the determination unit.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the embodiments of the present invention, it is possible to provide a stepping motor control device, a timepiece, and a stepping motor control method that are excellent in energy efficiency.

Drawings

Fig. 1 is a diagram showing an example of a configuration of a timepiece according to an embodiment.

Fig. 2 is a diagram showing an example of the configuration of the pointer driving unit in the embodiment.

Fig. 3 is a diagram showing an example of a normal drive pulse in the embodiment.

Fig. 4 is a diagram showing an example of the fixed pulse in the embodiment.

Fig. 5 is a diagram showing an example of the value of the current flowing in the coil when the normal drive pulse is supplied to the stepping motor after the needle is passed by the normal drive pulse in the embodiment.

Fig. 6 is a diagram showing an example of the value of the current flowing in the coil when the normal drive pulse is supplied to the stepping motor after the needle is passed by the fixed pulse in the embodiment.

Fig. 7 is a diagram showing an example of a form of rotation of the rotor when the normal drive pulse is supplied to the stepping motor after the needle is passed by the normal drive pulse in the embodiment in time series.

Fig. 8 is a diagram showing an example of a form of rotation of the rotor in a case where a normal drive pulse is supplied to the stepping motor after the needle is passed by the fixed pulse in the embodiment in time series.

Fig. 9 is a diagram showing an example of a series of operations of the stepping motor drive control in the embodiment.

Fig. 10 is a diagram showing an example of the configuration of a timepiece according to another embodiment.

Fig. 11A is a diagram showing one example of a case where each of the normal drive pulse and the fixed pulse in the embodiment is applied in order.

Fig. 11B is a diagram showing one example of a case where each of the normal drive pulse and the fixed pulse in the embodiment is applied in order.

Fig. 11C is a diagram showing one example of a case where each of the normal drive pulse and the fixed pulse in the embodiment is applied in order.

Fig. 11D is a diagram showing one example of a case where each of the normal drive pulse and the fixed pulse in the embodiment is applied in order.

Detailed Description

An example of a timepiece according to an embodiment will be described with reference to the drawings.

Fig. 1 is a diagram showing an example of the configuration of a timepiece 1 according to the embodiment.

[ functional constitution of timepiece 1 ]

The timepiece 1 includes a hand driving unit 110, a timepiece case 152, an analog display unit 153, a movement 154, and hands 155.

The timepiece case 152 is a case that houses the hand driving unit 110, the analog display unit 153, the movement 154, and the hands 155. The pointer driving portion 110 is included in the movement 154.

The analog display unit 153 is a dial having scale marks. Movement 154 comprises a mechanical mechanism for driving the various parts of timepiece 1. The hands 155 include an hour hand, a minute hand, a second hand, and other hands.

The pointer driving unit 110 includes a stepping motor control device 100 and a stepping motor 151. The stepping motor control device 100 includes an oscillation circuit 101, a frequency dividing circuit 102, a control circuit 103, a determination unit 51, a drive control unit 52, an arithmetic unit 53, and a motor drive circuit 106.

The oscillation circuit 101 generates a signal having a predetermined frequency, and transmits the generated signal to the frequency divider circuit 102. The frequency divider circuit 102 divides the frequency of the signal received from the oscillator circuit 101 to generate a clock signal serving as a reference for time counting, and transmits the generated clock signal to the control circuit 103. The control circuit 103 transmits control signals to the respective parts of the timepiece 1 based on the timepiece signal and the like received from the frequency dividing circuit 102, and controls the operations of the respective parts of the timepiece 1.

The determination unit 51 determines whether or not to correct the drive pulse based on a control signal received from the control circuit 103 and driving the stepping motor 151 and a previous control signal driving the previous stepping motor 151. Specifically, the determination unit 51 includes a previous drive pulse storage unit 510. Information of the previous drive pulse for driving the previous stepping motor 151 is stored in the previous drive pulse storage unit 510. The determination unit 51 compares the information of the previous drive pulse with the control signal received from the control circuit 103, and determines whether or not to correct the drive pulse. The determination unit 51 transmits information on whether or not to correct the drive pulse to the drive control unit 52. The determination unit 51 stores the information of the drive pulse in the previous drive pulse storage unit 510.

When the determination unit 51 determines to correct the drive pulse, the calculation unit 53 calculates the energy of the correction. The calculation unit 53 transmits information on the calculated corrected energy to the drive control unit 52. In this example, the arithmetic unit 53 is described as being provided in the stepping motor control device 100, but the arithmetic unit 53 may be included in the determination unit 51. The drive control unit 52 receives a control signal from the control circuit 103, information on whether or not to correct the drive pulse from the determination unit 51, and information on the corrected energy from the calculation unit 53. Based on the received information, the drive control unit 52 causes the motor drive circuit 106 to drive the stepping motor 151.

The motor drive circuit 106 is composed of a plurality of switching elements (not shown). In this example, the switching element refers to a P-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or an N-channel MOSFET. The motor drive circuit 106 drives the stepping motor 151 according to the connection state of the plurality of switching elements provided in the motor drive circuit 106. The connection states of the plurality of switching elements are controlled by the drive control unit 52. The stepping motor 151 moves the pointer 155 through the movement 154 in accordance with the driving pulse output from the stepping motor control device 100.

Fig. 2 is a diagram illustrating an example of the configuration of the pointer driving unit 110 in the embodiment. The pointer driving unit 110 includes a stepping motor 151 and a stepping motor control device 100.

[ constitution of stepping motor 151 ]

The stepping motor 151 includes a stator 201, a rotor 202, a rotor accommodating through hole 203, an inner notch 204, an inner notch 205, an outer notch 206, an outer notch 207, a core 208, and a coil 209. Hereinafter, the rotor accommodating through hole 203 is also referred to as a rotor through hole.

The magnetic core 208 is a member made of a magnetic material, and is joined to both ends of the stator 201. A coil 209 is wound around the core 208. One end of the coil 209 is connected to the terminal output 1, and the other end of the coil 209 is connected to the terminal output 2. The coil 209 itself flows a drive current i, and a magnetic flux is generated. The stator 201 is a member made of a magnetic material. The stator 201 gives the magnetic flux generated by the coil 209 to the rotor 202.

The rotor 202 is formed in a cylindrical shape and inserted in a rotatable state with respect to a rotor accommodating through hole 203 formed in the stator 201. That is, the stepping motor 151 includes a stator 201 provided with a rotor accommodating through hole 203, a rotor 202 rotatably disposed in the rotor accommodating through hole 203, and a coil 209 provided in the stator 201. In addition, the rotor 202 has an N pole and an S pole due to being magnetized. In the following description, an axis from the S pole to the N pole of the rotor 202 is referred to as a magnetic pole axis a, and a direction from the S pole to the N pole of the magnetic pole axis a is referred to as a positive direction of the magnetic pole axis a (or simply referred to as a direction of the magnetic pole axis a). The rotor 202 rotates the hand 155 clockwise through the train wheel by rotating in the normal rotation direction, and rotates the hand 155 counterclockwise through the train wheel by rotating in the reverse rotation direction. That is, the rotor 202 rotates in a normal direction in which the pointer 155 rotates clockwise, and a reverse direction in which the pointer 155 rotates in a reverse direction that is a direction opposite to the normal direction.

The inner notch 204 and the inner notch 205 are notches formed in the wall surface of the rotor accommodating through hole 203, and determine the stop position of the rotor 202 with respect to the stator 201. That is, for example, as shown in fig. 2, when the coil 209 is not excited, the rotor 202 is stationary at a position where the magnetic pole axis is orthogonal to a line segment connecting the inner notch 204 and the inner notch 205.

The outer notch 206 is a cut formed to be curved on the outer side of the stator 201, and the outer notch 207 is a cut formed to be curved on the inner side of the stator 201. A saturable portion 210 is formed between the outer notch 206 and the rotor accommodating through hole 203, and a saturable portion 211 is formed between the outer notch 207 and the rotor accommodating through hole 203.

The saturable portion 210 and the saturable portion 211 are portions as follows: the magnetic flux of the rotor 202 does not magnetically saturate, but magnetically saturates when the coil 209 is excited, and the magnetic resistance increases.

[ one example of the drive of the stepping motor 151 ]

The motor drive circuit 106 applies a drive pulse between the terminals (the first terminal output 1 and the second terminal output 2) of the coil 209, thereby generating a drive current i in the coil 209. The stepping motor control device 100 rotates the rotor 202 in a constant direction (for example, a normal rotation direction) by reversing the direction of the drive current i flowing through the coil 209 in accordance with the direction of the magnetic pole axis a at the stop position of the rotor 202.

As an example, a configuration in which the rotor 202 rotates in the normal rotation direction will be described. If the stepping motor control device 100 supplies a driving pulse between the first terminal output 1 and the second terminal output 2 of the coil 209, a magnetic flux is generated in the stator 201. Thereby, the saturable portion 210 and the saturable portion 211 are saturated, and the magnetic resistance of the saturable portion 210 and the saturable portion 211 becomes large. Subsequently, the rotor 202 is rotated counterclockwise by 180 degrees from the position of fig. 2 by the interaction of the magnetic poles generated in the stator 201 and the magnetic poles of the rotor 202, being stably stopped. By this rotation of about 180 degrees, the hand 155 of the timepiece 1 can move by a predetermined amount (by one scale). This prescribed amount of action is sometimes referred to as a step. In order to achieve the predetermined amount of operation, a gear train having an appropriate reduction ratio is appropriately disposed between the rotor 202 and the pointer 155. In one example of the present embodiment, the pointer 155 is moved by a one-step motion by about 1 second.

If the stepping motor control device 100 supplies a drive pulse to between the first terminal output 1 and the second terminal output 2 of the coil 209 with the rotor 202 in the state of fig. 2, a current flows in the coil 209. In this example, when a pulse is applied in which the first terminal output 1 is at a high potential and the second terminal output 2 is at a low potential (hereinafter, referred to as a positive direction), a current flows in the direction of the current i. If a current flows in the coil 209, a magnetic flux is generated in the stator 201. The rotor 202 rotates counterclockwise by approximately 180 degrees from the state of fig. 2 by the magnetic flux, and stops stably. When the rotor 202 is rotated by substantially 180 degrees from the state shown in fig. 2, the stepping motor control apparatus 100 generates magnetic flux in the stator 201 in a direction opposite to the direction in which the pulse in the positive direction is applied when the pulse in which the first terminal output 1 is at the low potential and the pulse in which the second terminal output 2 is at the high potential (hereinafter, referred to as the negative direction) is applied. Thereby, the saturable portion 210 and the saturable portion 211 are first saturated, and then the rotor 202 is further rotated counterclockwise by substantially 180 degrees by interaction of the magnetic poles generated in the stator 201 and the magnetic poles of the rotor 202, being stably stopped. At this time, the rotor 202 returns to the state of fig. 2. In this manner, signals (alternating signals) having different polarities are supplied to the coils 209, and the rotor 202 continuously rotates counterclockwise by approximately 180 degrees.

In the present embodiment, the stepping motor control device 100 drives the stepping motor 151 by a driving pulse. In this example, there are a normal drive pulse NP in which the pointer 155 is moved by one step movement for about 1 second and a fixed pulse FP other than the normal drive pulse NP in the drive pulse. Here, the normal drive pulse NP and the fixed pulse FP will be explained.

[ Driving pulse NP in general ]

Fig. 3 is a diagram showing an example of the normal drive pulse NP in the embodiment. Fig. 3 shows temporal changes in the potential of the first terminal output 1 and the potential of the second terminal output 2 of the coil 209. In the figure, the horizontal axis represents time, and the vertical axis represents potentials of the first terminal output 1 and the second terminal output 2. In the figure, the potentials of the first terminal output 1 and the second terminal output 2 are represented by two values of a high potential H and a low potential L.

At time t₁Previously, the potential of the first terminal output 1 was the high potential H, and the potential of the second terminal output 2 was the high potential H. In this state, since the two terminals of the coil 209 (between the first terminal output 1 and the second terminal output 2) are controlled to have the same potential, a current does not flow in the coil 209. Stepping motor control apparatus 100 at t₁The first terminal output 1 is controlled to a low potential L. If the first terminal output 1 is controlled to the low potential L, a potential difference is generated between both terminals of the coil 209, and thus a current flows in the coil 209. If current flows in the coil 209, magnetic flux is generated in the stator 201 as described above, and the rotor 202 starts to rotate. The stepping motor control device 100 is on for the elapsed on time t_ON1After that, the first terminal output 1 is controlled to the high potential H. In addition, the stepping motor control device 100 is configured to stop the stepping motor when the off time t elapses_OFF1After that, the first terminal output 1 is controlled to the low potential L again. That is, the stepping motor control apparatus 100 alternately controls (chopper control) the first terminal output 1 to a high potential H and a low potential L, thereby rotating the rotor 202. Will be on for a time t_ON1And off time t_OFF1The sum being recorded as the chopping period t_W1。

In the normal drive pulse NP, the stepping motor control device 100 turns on the stepping motor 151 with the energy corresponding to the on time t_ON1Relative to the chopping period t_W1The ratio (hereinafter, referred to as duty ratio) of (d) and the number of applied pulses. That is, the normal drive pulse NP is a chopping pulse that the stepping motor control apparatus 100 applies to the coil 209 in order to rotate the rotor 202 by substantially 180 degrees. For example, the usual drive pulses NP are chopping pulses with 5 pulses at a 50% (percent) duty cycle with a 0.5ms (millisecond) period.

Usually, the driving pulse NP is for moving the hand by a predetermined angleAnd (3) applying. For example, in a case where the stepping motor control device 100 drives the hand 155 (e.g., a second hand), the stepping motor control device 100 applies the normal drive pulse NP to the stepping motor 151 every 1 second. In this case, time t₁To time t₃Is 1 second, at time t₁To time t₂In between, the stepping motor control device 100 applies the normal drive pulse NP to the coil 209, and then at time t₃To time t₄Meanwhile, the stepping motor control device 100 applies the normal drive pulse NP to the coil 209.

[ fixed pulse FP ]

Fig. 4 is a diagram showing an example of the fixed pulse FP in the embodiment. The fixed pulse FP is a drive pulse used when the pointer 155 is fast-forwarded in the forward direction, when the pointer 155 is reversely rotated, or the like. In this one example, the on-time t of the pulse FP is fixed_ON2On-time t of the normal drive pulse NP_ON1Longer. That is, the fixed pulse FP drives the stepping motor 151 with a larger energy than the normal drive pulse NP.

The period of the fixed pulse FP may also be different from the period of the normal drive pulse NP. For example, in the case of fast forward rotation, the fixed pulse FP has a shorter period than the normal drive pulse NP. When fast forward rotation is performed, time t₁To time t₃Is shorter than 1 second. Therefore, the period of the fixed pulse FP can also be shorter than the period of the normal drive pulse NP. In addition, in the case other than the fast forward rotation, the period of the fixed pulse FP may coincide with the period of the normal drive pulse NP.

The fixed pulse FP may or may not be chopper-driven. In this one example, the on-time t of the pulse FP is fixed_ON2On-time t with normal drive pulse NP_ON1And is larger than it is, followed by chopping driving. However, the fixed pulse FP is also considered without chopper driving. In this example, the fixed pulse FP broadly includes a drive pulse other than the normal drive pulse NP, such as a pulse for driving the rotor 202 in reverse.

[ degaussing pulse DP ]

As described above, the stepping motor control device 100 applies the driving pulse to the stepping motor 151. The energy of the fixed pulse FP is larger than the energy of the usual drive pulse NP. In the fixed pulse FP, a current larger than the normal drive pulse NP is caused to flow in the coil 209, and thus the magnetic field generated in the stator 201 is also large. In the case where the stepping motor control device 100 applies a drive pulse to the stepping motor 151, the larger the applied energy, the larger the magnetic flux (residual magnetic flux) remaining in the saturable portion 210 and the saturable portion 211 of the stator 201 becomes. Therefore, since the energy of the fixed pulse FP is larger than the normal drive pulse NP, the residual magnetic flux remains more when the fixed pulse FP is applied than when the normal drive pulse NP is applied.

In the case where a residual magnetic flux remains in the saturable portion 210 and the saturable portion 211 by the application of the fixed pulse FP, the residual magnetic flux cancels out a magnetic flux generated by a drive pulse applied immediately after the fixed pulse FP. Therefore, the stepping motor control device 100 has to apply energy for canceling the residual magnetic flux and energy for rotating the rotor 202 to the coil 209 in order to rotate the rotor 202. The degaussing pulse DP is a pulse applied to the coil 209 to cancel the residual magnetic flux. In the present embodiment, the driving pulse is corrected by adding the degaussing pulse DP.

The addition of the degaussing pulse DP means that energy for canceling the residual magnetic flux is added to the normal drive pulse NP. For example, the normal drive pulse NP is further pulsed to add energy for canceling the residual magnetic flux to the normal drive pulse NP. Further, the degaussing pulse DP may be added by increasing the voltage of the normal drive pulse. In addition, the degaussing pulse DP may be added by increasing the pulse width of the normal drive pulse.

Fig. 5 is a diagram showing an example of the value of the current flowing in the coil 209 when the normal drive pulse NP is supplied to the stepping motor 151 after the needle is passed by the normal drive pulse NP in the embodiment. In the figure, the slave time t shown in fig. 3 is shown₁To time t₂The first terminal of the coil 209 outputs a potential of 1 and a potential flowing in the coil 209The value of the current. In this one example, before the normal drive pulse NP is applied (i.e., at time t)₁Previously) the applied drive pulse is the normal drive pulse NP. Therefore, the value of the current flowing through the coil 209 shown in the figure is the current flowing through the coil 209 when the residual magnetic flux does not remain in the stator 201.

Fig. 6 is a diagram showing an example of the value of the current flowing in the coil 209 when the normal drive pulse NP is supplied to the stepping motor 151 after the needle is passed by the fixed pulse FP in the embodiment. In the figure, the slave time t shown in fig. 3 is shown₁To time t₂The first terminal of the coil 209 outputs a potential of 1 and a value of a current flowing in the coil 209. In this one example, before the normal drive pulse NP is applied (i.e., at time t)₁Previously) the applied drive pulse is a fixed pulse FP. Therefore, residual magnetic flux remains in the saturable portion 210 and the saturable portion 211 of the coil 209 shown in the figure. In this case, the current flowing through the coil 209 is smaller than the case where the residual magnetic flux does not remain (i.e., the current i in fig. 5). Specifically, time t₁The first pulse of the normal drive pulse NP of (2) is used as the degaussing pulse DP for generating the residual magnetic flux, and the current that should flow in the coil 209 does not sufficiently flow. As a result, the stepping motor control apparatus 100 sometimes has the following problems: the energy necessary for the rotation of the rotor 202 cannot be imparted.

[ magnetic flux generated in the stator 201 and rotation of the rotor 202 when the normal drive pulse NP is supplied to the stepping motor 151 after the needle is passed by the normal drive pulse NP ]

Fig. 7 is a diagram showing an example of a form of rotation of the rotor 202 in the case where the normal drive pulse NP is supplied to the stepping motor 151 after the needle is passed by the normal drive pulse NP in the embodiment in time series. When the normal drive pulse NP is applied, a magnetic flux m (a) shown by an arrow in the figure is generated in the stator 201. Subsequently, if the saturable portions 210, 211 are saturated and the magnetic resistances of the saturable portions 210, 211 become large, the magnetic poles generated in the stator 201 interact with the magnetic poles of the rotor 202 (B), the rotor 202 rotates counterclockwise, and stops in a state of rotating approximately 180 degrees (C). In this case, the residual magnetic flux rm (c) is generated in the saturable portion 210 and the saturable portion 211, but the magnitude thereof is negligible.

Next, the normal drive pulse np (d) is applied in reverse. In this case, the residual magnetic flux RM is a residual magnetic flux of such a degree that it can be ignored, and therefore, the magnitude of the magnetic field M generated by the normal drive pulse NP is not affected (or can be affected) invisibly. Thus, a magnetic field m (e) is generated as indicated by the arrow in the figure. Subsequently, if the saturable portions 210, 211 are saturated and the magnetic resistances of the saturable portions 210, 211 become large, the magnetic poles generated in the stator 201 interact with the magnetic poles of the rotor 202 (F), the rotor 202 rotates counterclockwise, and stops in a state of rotating approximately 180 degrees (G).

[ magnetic flux generated in the stator 201 and rotation of the rotor 202 when the normal drive pulse NP is supplied to the stepping motor 151 after the needle passing by the fixed pulse FP ]

Fig. 8 is a diagram showing an example of a form of rotation of the rotor 202 in a case where the normal drive pulse NP is supplied to the stepping motor 151 after the needle is passed by the fixed pulse FP in the embodiment in time series. In the case where the fixed pulse FP is applied, a magnetic flux m (a) as indicated by an arrow in the drawing is generated in the stator 201. Subsequently, if the saturable portions 210, 211 are saturated and the magnetic resistances of the saturable portions 210, 211 become large, the magnetic poles generated in the stator 201 interact with the magnetic poles of the rotor 202 (B), the rotor 202 rotates counterclockwise, and stops in a state of rotating substantially 180 degrees (i.e., a state shown in fig. 8 (C)). In this case, since the energy by the fixed pulse FP is larger than that by the normal drive pulse NP, the residual magnetic flux rm (c) is generated in the saturable portion 210 and the saturable portion 211.

Next, the normal drive pulse np (d) is applied in reverse. In this case, since the residual magnetic flux RM is generated in the saturable portion 210 and the saturable portion 211, the magnetic field M generated by the normal drive pulse NP is cancelled (E) by the residual magnetic flux RM. Therefore, the magnitude of the magnetic field M generated by the normal drive pulse NP does not have enough energy to rotate the rotor 202. That is, the drive pulse NP normally gives a force (F) to rotate the rotor 202 counterclockwise, but the force is not so large that the rotor 202 rotates by approximately 180 degrees. As a result, after the normal drive pulse NP is applied, the rotor 202 cannot rotate by substantially 180 degrees, and is stopped (G) in a state before the normal drive pulse NP is applied (state of (C)).

The stepping motor control device 100 determines whether or not to add the degaussing pulse DP to the normal drive pulse NP based on whether the drive pulse applied before the normal drive pulse NP is the normal drive pulse NP or the fixed pulse FP. Fig. 9 is a diagram showing an example of a series of operations of the stepping motor drive control in the embodiment.

[ determination of the case of addition of a degaussing pulse DP ]

(step S10) the control circuit 103 sends information on the next drive pulse to the determination section 51 and the drive control section 52. The determination unit 51 determines whether or not the information on the next drive pulse is a fixed pulse FP. In the case where the next drive pulse is not the fixed pulse FP (i.e., step S10; no), the judgment part 51 advances the process to step S12. When the next drive pulse is the fixed pulse FP (i.e., step S10; yes), the judgment section 51 advances the process to step S18.

(step S12) the determination unit 51 determines whether or not the previous drive pulse is the fixed pulse FP. Specifically, the determination unit 51 determines whether the previous drive pulse information stored in the previous drive pulse storage unit 510 is the normal drive pulse NP or the fixed pulse FP. The determination unit 51 sends the result of the determination to the drive control unit 52. In the case where the previous drive pulse is not the fixed pulse FP (i.e., step S12; no), the judgment part 51 advances the process to step S17. In the case where the information of the last driving pulse is the fixed pulse FP (i.e., step S12; yes), the process proceeds to step S14.

(step S14) the drive control unit 52 adds the degaussing pulse DP based on the information received from the determination unit 51. In this example, when the information received from the determination unit 51 indicates that the previous drive pulse is the fixed pulse FP, the drive control unit 52 adds the predetermined degaussing pulse DP to the normal drive pulse NP. The calculation unit 53 may calculate the energy of the degaussing pulse DP added at this time. In this case, the arithmetic unit 53 determines the energy of the degaussing pulse DP based on the energy of the fixed pulse FP applied before the normal drive pulse NP. The drive control unit 52 adds the degaussing pulse DP determined by the calculation unit 53 to the next normal drive pulse NP to which the fixed pulse FP is applied.

Further, a plurality of degaussing pulses may be added to one normal drive pulse NP. In this case, the calculation unit 53 may reduce the magnitude of the applied degaussing pulse DP in a stepwise manner. For example, the degaussing pulse DP may be added to the next normal drive pulse NP of the fixed pulse FP, and a smaller degaussing pulse DP may be added to the next normal drive pulse NP.

In other words, in this case, the arithmetic unit 53 adds the degaussing pulse DP having an energy based on the fixed pulse FP applied before the normal drive pulse NP to the normal drive pulse NP, and further adds the second degaussing pulse DP having an energy smaller than that of the degaussing pulse DP to the next normal drive pulse NP.

In addition, the energy of the degaussing pulse DP is determined by the voltage of the pulse, the duty cycle of the pulse or the length of the on-time of the pulse. For example, when the energy of the degaussing pulse DP is controlled by a voltage, the calculation unit 53 may determine the voltage value of the degaussing pulse DP based on the energy of the fixed pulse FP applied before the normal drive pulse NP. In this case, a drive voltage determination unit 51' (fig. 10) may be provided for determining the voltage of the normal drive pulse NP based on whether or not the pulse applied before the normal drive pulse NP is the fixed pulse FP. That is, the drive voltage determination unit 51' determines to increase the voltage of the normal drive pulse NP or to maintain the voltage of the normal drive pulse NP as it is, based on whether or not the pulse applied before the normal drive pulse NP is the fixed pulse FP. Fig. 10 is a diagram showing an example of the structure of a timepiece according to another embodiment of the present invention. The drive voltage determination unit 51' shown in fig. 10 functions in the same manner as the determination unit 51 except that it determines whether or not the voltage of the normal drive pulse NP is increased.

(step S16) the drive control unit 52 causes the motor drive circuit 106 to drive the stepping motor 151 by the degaussing pulse DP and the normal drive pulse NP, and ends the process.

(step S17) the drive control unit 52 causes the motor drive circuit 106 to drive the stepping motor 151 by the normal drive pulse NP, and ends the process.

(step S18) the drive control unit 52 causes the motor drive circuit 106 to drive the stepping motor 151 by the fixed pulse FP, and ends the process.

The drive control unit 52 selectively applies the normal drive pulse NP, the fixed pulse FP, or the degaussing pulse DP and the normal drive pulse NP. That is, the drive control unit 52 drives the stepping motor 151 by the normal drive pulse NP or the fixed pulse FP based on the result determined by the determination unit 51.

Each of fig. 11A to 11D is a diagram showing one example of the case where each of the normal drive pulse NP and the fixed pulse FP in the embodiment is applied in order.

Fig. 11A shows a case where the normal drive pulse NP is applied after the normal drive pulse NP. The time t in this case will be described₃And (4) processing. In the control circuit 103, since the next drive pulse is not the fixed pulse FP (i.e., step S10; no in fig. 9) and the previous pulse is not the fixed pulse FP (i.e., step S12; no in fig. 9), the drive control section 52 outputs the normal drive pulse NP to the motor drive circuit 106 to drive the stepping motor 151 (i.e., step S17 in fig. 9).

Fig. 11B shows a case where the fixed pulse FP is applied after the fixed pulse FP. The time t in this case will be described₃And (4) processing. In the control circuit 103, since the next drive pulse is the fixed pulse FP (i.e., step S10; yes in fig. 9), the drive control section 52 outputs the fixed pulse FP to the motor drive circuit 106 to drive the stepping motor 151 (i.e., step S18 in fig. 9).

Fig. 11C shows a case where the fixed pulse FP is applied after the normal drive pulse NP. The time t in this case will be described₃And (4) processing. In the control circuit 103, since the next drive pulse is the fixed pulse FP (i.e., step S10; yes in fig. 9), the drive control section 52 outputs the fixed pulse FP to the motor drive circuit106, thereby driving the stepping motor 151 (i.e., step S18 in fig. 9).

Fig. 11D shows a case where the normal drive pulse NP is applied after the fixed pulse FP. The time t in this case will be described₃And (4) processing. Since the next drive pulse in the control circuit 103 is not the fixed pulse FP (i.e., no in step S10 in fig. 9) and the previous pulse is the fixed pulse FP (i.e., yes in step S12 in fig. 9), the drive control unit 52 adds a predetermined degaussing pulse DP to the normal drive pulse NP (i.e., step S14 in fig. 9). The drive control unit 52 outputs the normal drive pulse NP to which the degaussing pulse DP is added to the motor drive circuit 106 by the degaussing pulse DP and the normal drive pulse NP, and drives the stepping motor 151 (i.e., step S18 in fig. 9).

[ summary of effects of embodiments ]

As described above, the stepping motor control apparatus 100 determines whether to add the degaussing pulse DP based on whether the previous drive pulse is the normal drive pulse NP or the fixed pulse FP.

According to the above embodiment, the stepping motor control device 100 includes the determination unit 51 and the drive control unit 52, and controls the stepping motor 151 based on the previous drive pulse. When the previous drive pulse is the fixed pulse FP, the stepping motor control device 100 adds the degaussing pulse DP for canceling the residual magnetic flux to the drive pulse. In the case where the previous drive pulse is the normal drive pulse NP, the stepping motor control apparatus 100 does not add the degaussing pulse DP to the drive pulse. When the previous drive pulse is the fixed pulse FP, the stepping motor control device 100 adds the degaussing pulse DP for canceling the residual magnetic flux to the drive pulse. Therefore, the stepping motor 151 is not driven to be insufficient in energy. The stepping motor control device 100 determines whether or not to add the degaussing pulse DP based on whether the previous drive pulse is the normal drive pulse NP or the fixed pulse FP. Therefore, unnecessary energy is not consumed. Therefore, the stepping motor control device 100 can perform energy-efficient control.

In addition, according to the above-described embodiment, the fixed pulse FP has a longer on time in one period than the normal drive pulse NP. In this case, the residual magnetic flux generated in the saturable portion 210 and the saturable portion 211 after the fixed pulse FP is applied is larger than the residual magnetic flux generated after the normal drive pulse NP is applied. When the previous drive pulse is the fixed pulse FP, the stepping motor control device 100 adds the degaussing pulse DP for canceling the residual magnetic flux to the drive pulse. Therefore, the stepping motor control device 100 can cancel the residual magnetic flux.

In addition, according to the above-described embodiment, both the normal drive pulse NP and the fixed pulse FP may be applied to the second hand. In this case, the period of the driving pulse NP generally coincides with the period of the fixed pulse FP. The fixed pulse FP can be used not only when the pointer 155 is fast-forwarded in the forward direction or in the reverse direction, but also when the pointer 155 is driven in the same cycle as the normal drive pulse NP. That is, even if the period of the fixed pulse FP is the same as the period of the normal drive pulse NP, the energy of the fixed pulse FP may be larger than that of the normal drive pulse NP. In this case, a residual magnetic flux may be generated in the saturable portion 210 and the saturable portion 211 after the fixed pulse FP is applied. Even in such a case, the stepping motor control apparatus 100 can cancel the residual magnetic flux by adding the degaussing pulse DP to the normal drive pulse NP.

In addition, according to the above-described embodiment, the period of the fixed pulse FP may be different from the period of the normal driving pulse NP. In the present embodiment, the drive cycle is not fixed because the pointer 155 may be fast-forwarding and forward-rotating. The stepping motor control device 100 adds a degaussing pulse DP to a normal drive pulse NP applied after a fixed pulse FP having more energy than the normal drive pulse NP is applied. Therefore, the stepping motor control device 100 can cancel the residual magnetic flux even when the driving frequency of the normal driving pulse NP is different from the driving frequency of the fixed pulse FP.

In addition, according to the above embodiment, the stepping motor control device 100 includes the arithmetic unit 53. The arithmetic unit 53 determines the energy of the degaussing pulse DP based on the energy of the fixed pulse FP applied before the normal drive pulse NP. The stepping motor control device 100 includes the arithmetic unit 53, and can specify the energy of the degaussing pulse DP. Therefore, the stepping motor control device 100 includes the calculation unit 53, and can add the degaussing pulse DP having the energy necessary to cancel the residual magnetic flux. That is, the stepping motor control device 100 can perform control with high energy efficiency.

In addition, according to the above-described embodiment, the calculation unit 53 reduces the magnitude of the degaussing pulse DP in a stepwise manner. The stepping motor control apparatus 100 adds the degaussing pulse DP to the next normal drive pulse NP of the fixed pulse FP, and further adds a smaller degaussing pulse DP to the next normal drive pulse NP. Therefore, even when the residual magnetic flux cannot be canceled by one normal drive pulse NP, the stepping motor control apparatus 100 can cancel the residual magnetic flux by the next normal drive pulse NP.

In addition, according to the above-described embodiment, the stepping motor control apparatus 100 determines the energy of the degaussing pulse DP by the voltage of the pulse. This makes it possible to apply energy used for canceling the residual magnetic flux with higher accuracy. Therefore, the stepping motor control apparatus 100 determines the energy of the degaussing pulse DP from the voltage of the pulse, and can degauss with higher accuracy.

In the above-described embodiment, the residual magnetic flux is canceled by increasing the voltage of the normal drive pulse NP pulse by adding the degaussing pulse DP instead of the normal drive pulse NP. Therefore, even if a pulse of the same time as the normal drive pulse NP is applied, the stepping motor control apparatus 100 can demagnetize the residual magnetic flux by applying the normal drive pulse NP of a larger voltage.

All or a part of the functions of the timepiece 1 described above may be recorded as a program in a computer-readable recording medium, and the program may be executed by a computer system. The computer system is a system including hardware such as an OS, peripheral devices, and the like. The recording medium that can be Read by the computer is, for example, a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), a portable medium such as a CD-ROM, a storage device such as a hard disk built in a computer system, a Random Access Memory (RAM) provided in a network such as the internet, or the like. In addition, a volatile memory is an example of a recording medium that stores a program for a certain time.

The program may be transmitted to another computer system via a transmission medium (for example, a network such as the internet, or a communication line such as a telephone line).

The program may be a program that realizes all or a part of the functions described above. Further, the program that realizes a part of the above functions may be a program that can be realized in combination with a program that records the above functions in a computer system in advance, a so-called differential program.

While the embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to the above-described embodiments, and may include design changes and the like within a range not departing from the gist of the present invention.

Description of the symbols

1 … … clock, 151 … … stepping motor, 152 … … clock case, 153 … … analog display part, 154 … … movement, 155 … … pointer, 100 … … stepping motor control device, 110 … … pointer driving part, 101 … … oscillating circuit, 102 … … frequency dividing circuit, 103 … … control circuit, 51 … … determination part, 52 … … driving control part, 53 … … arithmetic part, 106 … … motor driving circuit, 203 … … rotor containing through hole, 202 … … rotor, 201 … … stator, 206 … … outer notch, 207 … … outer notch, 210 … … saturable part, 211 … … saturable part, 204 … … inner notch, 205 … … inner notch, 208 … …, 209 … … coil, NP … … normal driving pulse, FP … … fixed pulse, DP … … degaussing pulse.