Power management method for solar energy meter

Abstract

The present invention relates to a power management method (500) for a solar watch (200) or a solar automatic watch (200). The power management method (500) comprises providing (510) a main power source (110) from at least one energy supply (111). When the main power source (110) reaches at least one main threshold (511) and / or at least one auxiliary threshold (512), the main power source (110) is converted (530) into an auxiliary power source (120). The auxiliary power source (120) is used to supply (550) a motor (180) so as to wind (570) a main spring (190) via the motor (180).

Description

Technical Field

[0001] The present invention relates to a power management method. In particular, the present invention relates to an electric winder for a manual or self-winding watch, the winder comprising an electric motor, a battery arranged to power the motor, a solar cell arranged to charge the battery, an internal clock and electronic means for controlling the motor and implementing the power management method. Background Art

[0002] For more than a hundred years, manual or automatic watches have enabled mechanical watches to remain wound and run permanently during normal use. The required energy is obtained from manual winding, for example using the crown, or from mechanical movement derived from the user's natural movement. However, once at rest, the mainspring slowly releases all the mechanically stored energy into the watch movement, and the watch will stop typically after 48 to 80 hours.

[0003] Document US4901295 discloses a barrel winding device comprising a solar cell, a capacitor connected to the terminals of the solar cell, a stepper motor and a control circuit. The terminals of the stepper motor are connected to the terminals of the capacitor, wherein in this connection the switch is arranged to allow an electric pulse to be supplied directly from the capacitor to the motor, i.e. a drive pulse having the voltage of the capacitor. The control circuit is arranged so as to trigger the drive pulse when the capacitor voltage reaches a voltage threshold / reference. Further, in order to prevent the motor from receiving a drive pulse before it stops, i.e. in the case of intensive illumination, a triggering prohibits controlling the switch during a given period of time required for the rotor to make a complete step.

[0004] Document DE 10 2016 211 503 B3 provides a similar teaching. Each time an energy supply including a solar cell reaches a certain voltage threshold value U1 , a drive pulse with a constant duration is supplied directly from the energy supply to the stepper motor. Summary of the invention

[0005] The present invention relates to a power management method for a solar watch or a solar automatic watch, the power management method comprising:

[0006] - providing main power from an energy supply including said at least one solar cell;

[0007] It is characterized in that the power management method also includes:

[0008] - converting the main power supply into an auxiliary power supply having alternately off periods and on periods, each on period starting when the main power supply reaches a second voltage threshold and ending when the main power supply then reaches a first voltage threshold lower than the second voltage threshold, the auxiliary power supply being regulated in each on period so that when the voltage of the main power supply exceeds a third voltage threshold higher than the first voltage threshold and lower than the second voltage threshold, the supply voltage of the auxiliary power supply is maintained at the third voltage threshold;

[0009] - supplying the motor with the auxiliary power supply during at least part of each on-period by chopping the supply voltage into at least one periodic modulated signal provided by the auxiliary power supply; and

[0010] - Winding the mainspring via said motor.

[0011] Due to this arrangement, the motor (preferably the stepper motor) driven by solar energy can wind the mainspring of a conventional mechanical watch and can operate at its maximum efficiency even in low light conditions. Further, given sufficient ambient light, the mechanical watch will remain mechanically loaded even when not actively in use. Such a solar automation mechanism can operate on light power alone, or combine solar and mechanical energy acquisition methods to maintain optimal loading for all user conditions.

[0012] According to an embodiment, the at least one energy supply comprises at least one solar cell and / or at least one capacitor.

[0013] According to an embodiment, the at least one energy supply is supplied by light.

[0014] Due to one of these arrangements the solar watch is powered via sunlight, ambient light and / or by stored energy of the at least one capacitor.

[0015] According to an embodiment, when the main power source reaches the at least one auxiliary threshold, the at least one energy supply is partially charged or discharged, preferably, when the main power source reaches the at least one auxiliary threshold, the at least one capacitor is partially charged or discharged.

[0016] Due to this arrangement, the motor is driven only when there is enough energy available for efficient operation.

[0017] According to an embodiment, the power management method comprises stopping converting the main power source into the auxiliary power source when the main power source reaches a first voltage threshold, preferably when the main power source is below the first voltage threshold.

[0018] With this arrangement, if sufficient voltage is not maintained for efficient operation, the stored power is isolated from the motor.

[0019] According to an embodiment, the auxiliary power source is an auxiliary square wave; the auxiliary square wave comprises at least one voltage amplitude, at least one duty cycle and / or period.

[0020] According to an embodiment, the power management method comprises chopping the auxiliary power supply at least once into a modulated signal having at least one auxiliary duration.

[0021] According to an embodiment, the modulated signal is transformed into at least one first auxiliary square wave and one second auxiliary square wave; the at least one first auxiliary square wave and the one second auxiliary square wave being in anti-phase with respect to each other.

[0022] According to an embodiment, the modulated signal is equal to the at least one first auxiliary square wave or the at least one second auxiliary square wave.

[0023] Due to one of these arrangements, available energy is transformed into at least one waveform capable of efficiently driving the motor.

[0024] According to an embodiment, the on-period of the auxiliary power supply has a main duration which is a function of the energy stored in the at least one capacitor, the energy consumption and the energy delivered by the at least one solar cell.

[0025] Due to one of these arrangements, available energy is transformed into at least one waveform capable of efficiently driving the motor.

[0026] According to an embodiment, the main duration is longer than an auxiliary duration defined by the periods of the first and second periodic modulated signals respectively provided to the two supply terminals of the motor, preferably at least ten times longer than the auxiliary duration.

[0027] According to an embodiment, the at least one assistance duration is determined to maximize the efficiency of the motor.

[0028] Due to one of these arrangements, energy-wasting start-stop events are limited.

[0029] According to an embodiment, the power management method comprises performing a delay configured to delay supplying the motor with the auxiliary power source.

[0030] Due to this arrangement, efficiency losses are prevented by ensuring that the chopping signal is established before energy is supplied to the motor. The present invention relates to a solar watch configured to implement a power management method according to an aspect of the present invention and comprising a mainspring, a motor configured to wind the mainspring, and at least one solar cell configured to supply main power to the motor.

[0031] Due to this arrangement, the motor (preferably the stepper motor) driven by solar energy can wind the mainspring of a traditional manually wound mechanical watch and can operate at its maximum efficiency even in low light conditions. Further, given sufficient ambient light, the mechanical watch will remain mechanically loaded even when not actively in use. Such a mechanism can operate on light power alone, or combine solar and mechanical manual winding energy acquisition methods to maintain optimal loading for all user conditions.

[0032] The present invention relates to a solar automatic watch configured to implement a power management method according to an aspect of the present invention, and comprising a mainspring, an oscillating weight configured to wind the mainspring, a motor configured to wind the mainspring, and at least one solar cell configured to supply main power to the motor.

[0033] Due to this arrangement, the motor (preferably the stepper motor) driven by solar energy can wind the mainspring of a conventional mechanical watch and operate at its maximum efficiency even in low light conditions. Further, given sufficient ambient light, the mechanical watch will remain mechanically loaded even when not actively in use. Such an automated mechanism can operate on light power alone, or combine solar and mechanical energy acquisition methods to maintain optimal loading for all user conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The foregoing and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of embodiments, which is given by way of illustration and not limitation, with reference to the accompanying drawings, in which:

[0035] - Figure 1A , Figure 1B and Figure 1C Each of the 200 and 201 represents a circuit for a solar watch 200 or a solar automatic watch 200 according to an embodiment of the present invention;

[0036] - Figure 2 Represents different light conditions for the solar watch 200 or the solar automatic watch 200 according to an embodiment of the present invention;

[0037] - Figure 3 shows a power management method 500 according to an embodiment of the present invention;

[0038] - Figure 4 denoting a motor 180 supplied by the auxiliary power source 120 according to an embodiment of the present invention;

[0039] - Figure 5 and Figure 6 represent the duty cycle and mainspring speed as a function of illumination, respectively;

[0040] - 7A to 10B The auxiliary power source 120 , at least one first auxiliary square wave 126 , and at least one second auxiliary square wave 127 are shown. DETAILED DESCRIPTION

[0041] Electrical watch winders are known. These are devices that can be used to prevent a self-winding watch from stopping when it has not been worn for a certain period of time. A self-winding watch is fitted with a mechanism that automatically winds the mainspring using the arm movements of the person wearing the watch as a driving force. When the self-winding watch is worn, the movement causes an oscillating weight provided for this purpose to rotate or oscillate inside the watch. The oscillating weight is in turn arranged to transfer energy that sets it in motion to a gear train that winds the mainspring or barrel. It will therefore be clear that a self-winding watch that remains stationary does not wind.

[0042] One place where a watch is particularly likely to remain motionless for a long time is, for example, in a shop window. Indeed, it is not uncommon for a large number of watches to be statically displayed, for example in a watch shop window display area. It is therefore particularly advantageous to use an internal electrical winding mechanism in such an environment. However, the motor, preferably the stepper motor, when optimally driven draws more power than can be supplied by typical low or medium light conditions when using standard solar cells. Therefore, the present invention proposes a power management method 500 for a solar watch 200 or a solar automatic watch 200, wherein the motor, preferably the stepper motor, can wind the mainspring of a conventional mechanical watch and can operate at its maximum efficiency even in low light conditions, and the solar watch 200 or the solar automatic watch 200 is configured to implement the power management method 500 according to an aspect of the present invention. The advantage of the solar watch 200 or the solar automatic watch 200 is to have a manual watch movement or an automatic watch movement, respectively, that can be wound even when it is not manually wound or has not been worn for a certain period of time.

[0043] Further, given sufficient ambient light, a mechanical watch will remain mechanically charged even when not actively in use.Such a solar automation mechanism can operate on light power alone, or combine solar and mechanical energy acquisition methods to remain optimally charged for all user conditions.

[0044] Thus, the power management method 500 may provide 510 the main power source 110 from at least one energy supply 111, the at least one energy supply 111 comprising as in Figures 1A to 1C 1 and 13. In practice, the solar meter 200 is supplied by sunlight and / or ambient light via the at least one solar cell 112. A portion of the energy obtained via the at least one solar cell 112 can be stored by the at least one capacitor 113, which in turn can supply the solar meter 200 as the main power source 110, and another portion of the energy obtained via the at least one solar cell 112 can be directly supplied to the solar meter 200 as the main power source 110.

[0045] When the main power source 110 reaches at least one threshold value (preferably a second voltage threshold value 512), the main power source 110 may be converted 530 to an auxiliary power source 120, which may be an auxiliary square wave voltage 121 having a voltage amplitude and a duty cycle and a period, until the main power source 110 reaches a first voltage threshold value 511 that is lower than the second voltage threshold value 512. When the main power source 110 is higher than a third voltage threshold value 513 between the first voltage threshold value 511 and the second voltage threshold value 512, the voltage amplitude of the auxiliary square wave voltage 121 may be equal to the third voltage threshold value, such as 7A to 10B As depicted in .

[0046] The auxiliary square wave voltage 121 mentioned above may have at least one main duration 125, which is a function of the energy stored in the at least one capacitor 113, the energy consumption and the energy delivered by the at least one solar cell, and may be determined by the first voltage threshold 511 and the second voltage threshold 512, such that the available energy may be transformed into at least one waveform that may efficiently drive the motor 180. For example, a Lavet stepper motor from an ETA movement may be used, because the Lavet stepper motor may generate sufficient torque at a sufficient speed to wind the mainspring. Further, as may be obtained from different 7A to 9B As will be appreciated, the at least one primary duration 125 may end when the primary power source 110 may be below the first voltage threshold 511 .

[0047] It can be shown that a Lavet stepper motor can be driven at, for example, 128 Hz, in which the minute axis is typically stepped once every 20 seconds, while generating at least 20 μNm on the minute axis and consuming less than 500 μW. Figure 1A and Figure 1B It is mentioned in 128 and marked as V IVThis frequency is obtained by switching the auxiliary power supply 120 to the crystal.

[0048] In this example, the Lavet motor rotates at 2×128 Hz, or 256 Hz, and the winding gear body rotates at 0.35 Hz, or once every 2.8 seconds, as can be seen in Figure 6 At this speed, the mainspring is fully wound in 1 hour and 24 minutes, and an electrical power requirement of 500 μW can be provided by at least one solar cell 112. This level of electrical power is available for illuminations exceeding 5 klx. Thus, at 700 lx, the winding time in pulse mode would increase from 1.4 hours to 10 hours for a movement with an autonomy of over 80 h.

[0049] As mentioned above, when the main power supply 110 reaches the second voltage threshold 512, the at least one energy supply 111 can be partially charged or discharged, preferably, when the main power supply 110 reaches the second voltage threshold 512, the at least one capacitor 113 is partially charged or discharged. If the voltage on the capacitor reaches or exceeds the second voltage threshold 512, for example 2.2V, depending on the input power and load, the output of the auxiliary power supply 120 can jump to a third voltage threshold 513, for example 1.8V, and the output will remain at 1.8V when the capacitor voltage exceeds 1.8V or follow the capacitor voltage between 1.8V and 1.7V (first voltage threshold 511), such as the at least one capacitor 113 can be charged and then can only be supplied to the motor when sufficient voltage is available to generate useful torque. As shown in the figures, the auxiliary power supply 120 can be between 1.7V and 1.8V. At this time, if the voltage on the at least one capacitor 113 exceeds 1.8V, the auxiliary power supply 120 can be different from the voltage on the at least one capacitor 113. Before the voltage on the at least one capacitor 113 reaches 2.2V (the second voltage threshold 512 ), the voltage on the auxiliary power source 120 is close to or equal to 0V.

[0050] After reaching the second voltage threshold 512, the motor 180 can be supplied 550 and the motor 180 can wind the mainspring 190 570. In order to supply the motor 180, the auxiliary power supply 120 can be chopped into a modulated signal having at least one auxiliary duration 129 determined to maximize the efficiency of the motor and being at most one tenth as long as the main duration 125, as shown in FIG. 7, and transformed into a first auxiliary square wave 126 and a second auxiliary square wave 127 equal to the modulated signal, such as the available energy is transformed into at least one waveform capable of efficiently driving the motor. In addition, the first auxiliary square wave 126 and the second auxiliary square wave 127 can be in anti-phase with respect to each other, as illustrated in FIG. 8, due to, for example, two NOT gates that flip the voltage applied to the motor 180. The D flip-flop ensures that both NOT gates are active only once the desired potential is available and the oscillator output is turned on, which can be utilized as in Figure 1A , Figure 1B , Fig. 7A , Fig.9A , Figure 7B and Fig. 9B Indicated as V v The auxiliary power supply 120 supplies the D flip-flop. In fact, after being chopped, the auxiliary power supply 120 can be delayed 540 before supplying 550 to the motor 180 to prevent efficiency losses by ensuring that the chopped signal is established before the motor is energized. The waveforms described as the first auxiliary square wave and the second auxiliary square wave can also be different waveforms, such as but not limited to bipolar square waves or square waves with a duty cycle of less than 50%, so that there are pauses between the pulses of the first auxiliary square wave 126 and the second auxiliary square wave 127. The most efficient waveform will depend on the type of motor or stepper motor used. Further, as can be obtained from different 7A to 9B As will be appreciated, the duration 115 of the first auxiliary square wave and the second auxiliary square wave may begin after the delay 540 and may continue as long as the main power source 110 is above the first voltage main threshold 511, such as at FIG. 8A to FIG. 9B As shown in the figure.

[0051] When the main power supply 110 reaches the first voltage threshold 511, preferably when the main power supply 110 is lower than the first voltage threshold 511, a stop 530 can occur to convert the main power supply 110 to the auxiliary power supply 120, so that when the voltage of the at least one capacitor 113 reaches or drops below the first voltage threshold 511, for example 1.7V, the output of the power module is turned off, thereby isolating the stored power from the motor if sufficient voltage is not maintained for efficient operation.

[0052] Another embodiment may use a microcontroller to act as a power management and drive signal generator. This has the advantage that it can be adapted to the environment. By turning the motor at an ideal speed, the charge of the capacitor can be maintained at an optimal level where the solar cell is most efficient. Perhaps more importantly, feedback can be added to determine whether the motor has advanced. This is important because it will allow the electronics to know whether high or low torque needs to be applied. The implementation described above is engineered to generate as much torque as possible to ensure that the mainspring is fully loaded. To do this, 70 μNm must be achieved or 15 μNm on the minute hand. When the mainspring is discharged, this requirement may be reduced to one-third. Therefore, a system can be considered that initially winds at a low torque, senses when this is insufficient, and then increases the bias voltage or pulse duration to ensure complete and optimal winding of the mainspring. It is estimated that twice the efficiency can be achieved compared to the given fixed torque example.

Claims

1. A power management method for a solar watch incorporating a manual or automatic movement, the movement comprising a barrel and a motor (180) arranged to allow electrical winding of the barrel, and supplied by at least one solar cell (112); the power management method (500) comprising: - providing (510) a main power supply (110) from an energy supply (111) comprising said at least one solar cell; The power management method (500) further comprises: - converting (530) the main power source (110) into an auxiliary power source (120) having alternately off periods and on periods, each on period starting when the main power source (110) reaches a second voltage threshold (512) and ending when the main power source then reaches a first voltage threshold (511) lower than the second voltage threshold, the auxiliary power source being regulated in each on period so that when the voltage of the main power source exceeds a third voltage threshold that is higher than the first voltage threshold and lower than the second voltage threshold, the supply voltage of the auxiliary power source is maintained at the third voltage threshold; - supplying (550) the motor (180) with the auxiliary power supply (120) during at least part of each on-period by chopping a supply voltage into at least one periodic modulated signal (121; 126; 127) provided by the auxiliary power supply; and - Winding (570) the mainspring (190) via the motor (180).

2. The power management method according to claim 1, wherein the at least one energy supply unit (111) comprises at least one capacitor (113).

3. The power management method according to claim 1 or 2, characterized in that: The auxiliary power supply (120) provides a first periodic modulated signal (127) and a second periodic modulated signal (126) which are in anti-phase relative to each other and are respectively provided to two supply terminals of the motor.

4. The power management method according to any one of the preceding claims, characterized in that The main duration (125) of each on-time period of the auxiliary power supply is at least ten times longer than the auxiliary duration (129) defined by the first periodic modulated signal and the second periodic modulated signal.

5. The power management method of claim 4, wherein the assistance duration (129) is determined to maximize the efficiency of the motor.

6. A power management method according to any one of the preceding claims, characterised in that The solar meter includes a delay circuit (540) configured to delay supplying the motor (180) with the auxiliary power source (120) after an on-period of the auxiliary power source has begun.

7. A solar watch configured to implement the power management method according to any one of the preceding claims and comprising a barrel, a motor (180) configured to wind the barrel and at least one solar cell (112) configured to supply main power (110) to the motor (180).

8. A solar automatic watch configured to implement the power management method according to any one of the preceding claims, and comprising a barrel, an oscillating weight configured to wind the barrel, a motor (180) configured to also wind the barrel, and at least one solar cell (112) configured to supply main power (110) to the motor (180).

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