System and method for operating an electromechanical lock

Abstract

Systems and methods for operating an electromechanical lock are described herein. According to one embodiment, the method includes harvesting ambient energy using an energy harvesting circuit and charging a buffer capacitor using the harvested ambient energy. The method also includes alternately connecting and disconnecting an electrical load and the buffer capacitor, wherein a capacitor voltage provided by the buffer capacitor during a discharge phase is applied to the electrical load, during which the electrical load is connected to the buffer capacitor and the capacitor voltage decreases, and wherein the buffer capacitor is recharged during a charging phase, during which the electrical load is disconnected from the buffer capacitor, during which the capacitor voltage increases again. The duration of the charging phase and the discharge phase are designed such that the capacitor voltage remains above a minimum supply voltage of the electrical load.

Description

Technical Field

[0001] The following disclosure pertains to the field of passive systems powered by energy harvesting. Background Technology

[0002] Energy harvesting is the process of obtaining electricity from one or more external sources, such as ambient electromagnetic fields, solar energy, thermal energy, wind energy, mechanical motion (e.g., vibration), etc., sometimes collectively referred to as "ambient energy." In this process, energy is captured (harvested) and stored for use in so-called passive systems, i.e., systems that do not have their own power source.

[0003] Energy harvesting circuits that convert ambient energy into electrical energy have attracted significant attention in both military and commercial fields. For example, some systems convert motion, such as the motion of ocean waves, into electricity for autonomously operating marine monitoring sensors. So-called "wearable electronic devices," which also lack their own power source, represent another area where energy harvesting is employed.

[0004] Energy harvesting circuits typically provide a relatively small amount of power and are therefore only suitable for powering low-power electronic devices. A very common application is RFID and NFC tags (RFID for Radio Frequency Identification, NFC for Near Field Communication), which obtain the power required for operation from the electromagnetic field generated by NFC-enabled devices (e.g., mobile phones). NFC is standardized in ISO / IEC 18092 (Near Field Communication Interfaces and Protocols-1) and ISO / IEC 21481 (Near Field Communication Interfaces and Protocols-2), and therefore will not be discussed in more detail here.

[0005] As mentioned, energy harvesting typically provides only a relatively small amount of electricity. Therefore, known energy harvesting circuits are generally insufficient to supply enough energy to loads such as electromechanical actuators (e.g., electric motors), which consume significantly more power than circuit systems such as RFID / NFC tags. In many applications, harvesting the necessary electrical energy from ambient energy sources for such loads would take an unreasonably long time or require enormous buffer capacitors. Summary of the Invention

[0006] This document describes a method for controlling an electrical load. According to one embodiment, the method includes harvesting ambient energy using an energy harvesting circuit and charging a buffer capacitor using the harvested ambient energy. The method also includes alternately connecting and disconnecting the electrical load and the buffer capacitor, wherein during a discharge phase, a capacitor voltage supplied by the buffer capacitor is applied to the electrical load, in which the electrical load is connected to the buffer capacitor and the capacitor voltage decreases, and wherein during a charging phase, the buffer capacitor is recharged, in which the electrical load is disconnected from the buffer capacitor, and the capacitor voltage increases again. The durations of the charging and discharging phases are designed such that the capacitor voltage remains above a minimum supply voltage of the electrical load.

[0007] Furthermore, this document describes an electromechanical lock. According to one embodiment, the electromechanical lock includes: a motor configured to move the latch of the lock; an energy harvesting circuit configured to harvest ambient energy using a near-field communication (NFC) antenna and further configured to charge a buffer capacitor using the harvested ambient energy; and a control circuit configured to alternately connect and disconnect the motor and the buffer capacitor. This is achieved in such a way that during a discharge phase, the capacitor voltage provided by the buffer capacitor is applied to the motor, during which the motor is connected to the buffer capacitor and the capacitor voltage decreases, and during a charging phase, the electrical load is disconnected from the buffer capacitor, causing the capacitor voltage to increase again. The duration of the charging and discharging phases is designed such that the capacitor voltage remains above the minimum supply voltage of the motor. Attached Figure Description

[0008] The following detailed description refers to the accompanying drawings. The drawings form a part of the specification and illustrate examples of how the invention can be used and implemented. It should be understood that, unless otherwise specifically stated, features of the various embodiments described herein can be combined with each other.

[0009] Figure 1 An exemplary application of a passive system is shown, which includes an electromechanical actuator, such as an electric motor, powered by a buffer capacitor, which itself is charged by an energy harvesting circuit.

[0010] Figure 2 An exemplary timing diagram is shown depicting the energy lost when a load (e.g., an actuator) is powered by a buffer capacitor.

[0011] Figure 3 An exemplary timing diagram illustrates a concept for controlling a load (e.g., an actuator) to efficiently utilize energy stored in a buffer capacitor and provided by an energy harvesting circuit.

[0012] Figure 4 Showing more details Figure 3 Part of it.

[0013] Figure 5 It shows in Figure 1 An exemplary implementation of the control circuit used in the embodiments.

[0014] Figure 6 An exemplary timing diagram illustrates the step-by-step output power of the load / actuator. Detailed Implementation

[0015] In the embodiments described herein, a passive system operating using electrical energy harvested via energy harvesting is described, wherein the passive system includes an electronically controlled actuator, such as an electromechanical actuator (e.g., an electric motor). It should be noted that the electronically controlled actuator is merely an arbitrary example of an electrical load requiring more electrical power than is typically available through energy harvesting. Furthermore, the energy harvesting circuitry used in the embodiments described herein extracts energy from an electromagnetic field generated by a device (e.g., a mobile phone) capable of near-field communication (NFC), a standard feature of most modern mobile phones. It should be noted that the concepts described herein can also be readily combined with energy harvesting circuitry that also harvests energy from other environmental energy sources (e.g., mechanical vibrations, solar radiation, etc.).

[0016] Figure 1 An example of the overall structure of a passive system is shown, which includes a buffer capacitor C. S Electromechanical actuators that supply power, such as electric motors (see...) Figure 1 , electrical load 3), the buffer capacitor C S It is charged by energy harvesting circuit 1. Figure 1 In the example, the energy harvesting circuit includes a capacitor C connected in parallel. R Antenna L forming an LC parallel resonant circuit R (It has a specific inductance). In NFC applications, the resonant circuit is designed to have approximately 13.56MHz (which corresponds to...). The resonant frequency of the antenna L. However, the resonant frequency is a design parameter that can vary in various applications. For example, the electromagnetic field generated by a device capable of wireless communication (especially a device supporting NFC, such as mobile device 10) in the antenna L. R A voltage is induced in the circuit, which is rectified by a rectifier circuit 11 coupled to the resonant circuit, and the output voltage of the rectifier circuit 11 is applied to the buffer capacitor C. S In the presence of an NFC field, the buffer capacitor C S It is charged by energy harvesting circuit 1.

[0017] Stored in buffer capacitor C S The electrical energy in it is equal to C S V S 2 / 2, where V S This represents the capacitor voltage, and C S This represents the capacitance of the buffer capacitor. The average power that can be output by the energy harvesting circuit 1 may be quite low (in the low milliwatt range, such as 5mW or less) and depends heavily on prior unknown parameters, such as the distance between the NFC-enabled devices 10, the output power of the NFC-enabled devices, etc. In an example where the energy harvesting circuit includes a small solar cell instead of an NFC antenna, one of the aforementioned unknown parameters is the current radiated by the solar cell.

[0018] exist Figure 1 In this system, the electrical load 3 is a motor, where the mechanical output power (which equals the output torque multiplied by the angular velocity) and therefore the motor's electrical power consumption may be significantly higher than the average power provided by the energy harvesting circuit 1. Therefore, continuous operation of the electrical load 3 is not feasible. However, in many applications, continuous operation of the load 3 is not required, and the energy required to operate the load for a certain period can be stored in the buffer capacitor C. S middle.

[0019] Figure 2 The timing diagram in the figure shows the sequence of events included in ... Figure 1 This is an example of an operating cycle of load 3 in a system. For the following discussion, it is assumed that load 3 requires a minimum supply voltage V. STOP In order to ensure normal operation. In the case of an electric motor, once the supply voltage V... S Decrease to value V STOP The motor rotor will then stop. This assumption (minimum supply voltage requirement) is valid for most electrical loads in practical applications. Figure 2 In the example, the motor requires a minimum voltage of approximately 2V. STOP The energy harvesting circuit can provide an open-loop supply voltage of approximately 3.3V, that is, when motor 3 is disconnected (first idle phase), Figure 2 (left side), buffer capacitor C S It can be charged up to V S =3.3V.

[0020] Once the motor is switched on, the capacitor voltage V S The voltage will decrease, while the motor rotor continues to rotate and output mechanical power. In this example, the capacitor voltage V must be... S Drop to threshold V STOPThe desired rotation of the rotor of motor 3 is achieved beforehand (e.g., a 180° rotation of the mechanical latch of a moving lock), because the motor rotor will stop rotating below this voltage threshold. From Figure 2 It can be seen that the buffer capacitor C is stored S The energy in (i.e., C) S V STOP 2 A large portion of / 2) remains unused. For DC motors, V STOP For example, it can be between 1.8V and 2.3V.

[0021] A buffer capacitor C must be selected. S Size and maximum capacitor voltage V S This allows load 3 (e.g., actuator, motor) to generate the desired output power W. A rough estimate ignoring losses yields W ≤ C. S V S 2 / 2-C S V STOP 2 / 2. Parameter V S It is usually limited by the energy harvesting method used, and the parameter V STOP The size of the buffer capacitor is usually determined by the type of load used in the system under consideration. Therefore, to increase the output power, a larger buffer capacitor is needed. In practical applications, large capacitors, which may be in the range of several mF, naturally have correspondingly large sizes, which may be unsuitable or undesirable for many applications.

[0022] Figure 3 The timing diagram illustrates the control of load 3 (e.g., an electromechanical actuator) to efficiently utilize the data stored in the buffer capacitor C. S A new concept for neutralizing the energy provided by energy harvesting circuit 1. Therefore, the load / actuator is operated intermittently, causing the capacitor voltage V to... S Maintain above the threshold voltage V STOP V ON With V OFF In the interval between (i.e., V) STOP <V OFF <V ON From the user's perspective, the actuator moves in a quasi-continuous manner because it is disconnected during this period to allow the buffer capacitor C to operate. S The recharging phase is relatively short. In practice, the actuator moves step by step, with the number of steps freely configurable. In practice, the number of steps will be so many that the actuator will perform the desired motion, or in other words, will output the desired (mechanical) work W.

[0023] like Figure 3As shown in the top diagram, once the ambient power becomes active (e.g., when mobile device 10 generates an NFC field, see...), Figure 1 ), buffer capacitor C S It is charged, and the capacitor voltage V S Increase until it reaches voltage level V ON Once the capacitor voltage V S Reaching threshold V ON (V S =V ON The load 3 (e.g., a motor) is controlled by the control circuit 2 (see also...). Figure 1 When load 3 is active (on), the capacitor voltage V... S The power consumption of load 3 is reduced because it exceeds the power supplied by energy harvesting circuit 1. Consequently, the power stored in capacitor C... S The net charge in the capacitor decreases, and the capacitor voltage V S decline.

[0024] Once the capacitor voltage V S Reaching V OFF (V S =V OFF Load 3 is then deactivated (disconnected) by control circuit 2. Once load 3 is disconnected, power consumption becomes essentially zero, and capacitor C... S It can be charged by energy harvesting circuit 1. Therefore, during this charging phase, the energy stored in the buffer capacitor C... S The net charge in the capacitor increases and the capacitor voltage V S Increase accordingly. Once the capacitor voltage V S Reaching the threshold V again ON Load 3 is then reactivated and the next discharge phase begins. Figure 3 The bottom diagram shows the load current (actuator current). While this is not always the case, in the implementation described herein, the buffer capacitor C... S Throughout the charging and discharging phases, the energy harvesting circuit 1 continuously charges the capacitor (assuming that the energy harvesting circuit 1 can harvest sufficient ambient energy). However, the capacitor voltage decreases during the discharging phase because the load 3 typically consumes (on average) more power than the energy harvesting circuit 1 can deliver, and therefore, the net charge change of the charge stored in the buffer capacitor during the discharging phase is negative.

[0025] Figure 4 The timing diagram shows more details. Figure 3 Part of the top image. Figure 4 In the example, the duration of the charging phase (during which load 3 is disconnected) is denoted as time t. offSimilarly, the duration of the discharge phase (during which load 3 is switched on) is expressed as time t. on As mentioned above, switching the load 3 (e.g., the motor) on and off can be controlled by the capacitor voltage V. S Reaching threshold V respectively ON and V OFF This is to trigger the process. However, it should be noted that, for example, the discharge phase of load 3 can also be set to a fixed time interval t. on In this case, at the capacitor voltage V S It has dropped to the threshold V OFF At that time, the load is not deactivated, but rather after a predetermined time interval (with t) has elapsed since the load was activated. on When the length of the load is reached (approximately), the load is deactivated. Since the current consumption of the load is usually (approximately) known, a time interval t can be set. on This causes the capacitor voltage V to be... S Reliably maintain a voltage above the minimum voltage V STOP .

[0026] Using the concepts discussed above, the desired output power of load 3 (e.g., the desired angular displacement performed by the motor) can be compared with the buffer capacitor C. S The size is separated. Therefore, the size of the capacitor can be significantly reduced, as well as the space required for the buffer capacitor and its associated cost. A smaller buffer capacitor will also reduce the initial charging time (see...). Figure 3 This reduces the time (t0), which can improve user satisfaction (because users need to wait less time before the actuator starts to move). Furthermore, when the buffer capacitor decreases to a lower capacitance, the unused energy C... S ·V STOP 2 The reduction of / 2 (discussed above) can improve the efficiency of the entire system.

[0027] Figure 5 It shows the control Figure 3 and Figure 4 An exemplary implementation of the control circuit 2 for the switching operation is shown. In this example, a transistor H-bridge is used to drive a load 3 (motor), wherein the transistor H-bridge includes p-channel MOS transistors T1 and T3 and n-channel MOS transistors T2 and T4, wherein transistors T1 and T2 form a first half-bridge, and transistors T3 and T4 form a second half-bridge, and the load 3 is connected between the center taps of the half-bridges. Driving an electrical load (and particularly a DC motor) using a transistor H-bridge is known in itself and therefore will not be discussed further herein. Logic circuit 21 is configured based on a buffer capacitor C. S The provided capacitor voltage V SThe current level and also based on predetermined parameters (e.g., voltage threshold V). ON and / or V OFF Maximum number of switching cycles cnt, time t on and / or t off The control circuit 2 may include gate signals for transistors T1, T2, T3, and T4, generated by means of factors such as the direction of actuator movement, etc. The control circuit 2 may include components that can be coupled to a buffer capacitor C. S A power management unit (PMU) 22 is connected to the other components of the control circuit 2. The PMU 22 is configured to provide a defined (e.g., regulated / stabilized) supply voltage V to the logic circuit 21 and optionally also to the transistor H-bridge. D Used to draw from (unregulated) input voltage V S Generate supply voltage V D The various concepts involved are known in themselves and therefore will not be discussed in more detail here. The PMU 22 can also be configured to split from the buffer capacitor C. S The received input power is distributed between control logic 22 and load 3.

[0028] The embodiments and their applications described herein are summarized below. It should be understood that the following is not an exhaustive discussion of the technical features of the embodiments, but rather an overview of some aspects. One embodiment relates to a method for controlling the electrical load of a passive system. Therefore, the method includes harvesting ambient energy using an energy harvesting circuit and using the harvested ambient energy to charge a buffer capacitor (see...). Figure 1 Energy harvesting circuit 1 and capacitor C S The method also includes alternately connecting and disconnecting the electrical load and the buffer capacitor, such that the capacitor voltage V provided by the buffer capacitor during the discharge phase... S The load is applied to the electrical load during this discharge phase, and the load is connected to a buffer capacitor (and the capacitor voltage V). S (The voltage is reduced), and during the charging phase, the buffer capacitor is recharged, during which the electrical load is disconnected from the buffer capacitor. The durations of the charging and discharging phases are designed such that the capacitor voltage V... S Maintain a supply voltage V higher than the minimum required for the electrical load. STOP Such alternating / intermittent operations are also achieved through... Figure 6 Visualize the graph, where Figure 6 The top image and Figure 3 The same as in, and Figure 6 The bottom diagram shows the output power of the load (e.g., angular displacement multiplied by output torque if the load is an electric motor). For example... Figure 6As shown, the output power increases during each discharge phase of the load activity, but does not increase during the charging phase because the load is inactive to allow the capacitor to recharge.

[0029] As mentioned, in one example, the electrical load could be an electromechanical actuator, such as an electric motor (e.g., a DC motor). Many energy harvesting concepts are known. In one specific example, ambient energy is generated by an NFC-enabled device (see...). Figure 1 The energy is generated by the electromagnetic field of the mobile phone 10. Once an NFC-enabled device is active near the NFC antenna included in the energy harvesting circuit, the energy harvesting circuit can harvest the energy.

[0030] In one example, the duration of the charging and discharging phases is determined by a voltage threshold (see [link to example]). Figure 3 and Figure 4 Threshold level V ON V OFF ) is determined. Therefore, by the capacitor voltage V S Reaching the upper threshold voltage level (see Figure 4 V ON When the electrical load is connected to the buffer capacitor (so that the capacitor voltage is applied to the electrical load), and the capacitor voltage V S Drop to the lower threshold voltage level (see Figure 4 V OFF When the electrical load is disconnected from the buffer capacitor, the connection between the electrical load and the buffer capacitor is alternately made and disconnected. In an alternative embodiment, the duration of the discharge phase is a predetermined time (see [reference]). Figure 4 , t on Set the charging phase duration to a predetermined time t. off That's also possible. Set the voltage threshold level V. ON V OFF and the duration t of the charging and discharging phases. on t off This causes the capacitor voltage V to be... S The supply voltage V should not drop to or below the minimum supply voltage of the load. STOP It should be understood that parameter V ON V OFF t on and t off They cannot be set independently of each other.

[0031] like Figure 6As shown, the electrical load and the buffer capacitor can be alternately connected and disconnected until the end of the nth discharge stage (where n is a predetermined integer greater than 1, n>1), or alternatively until the output power of the electrical load reaches the desired target level (see [reference]). Figure 6 W end ).

[0032] One example implementation relates to a method for controlling an electromechanical lock. Thus, a motor or another electromechanical actuator is mechanically coupled to the latch of the lock, and the method described above is used to charge a buffer capacitor and drive the motor to move the latch. It is assumed that moving the latch requires a specific (constant) output torque from the motor. Figure 6 The step in the bottom diagram can also be interpreted as angular displacement. As mentioned, the energy harvesting circuit can harvest energy from the NFC field generated by the NFC-enabled device. In this example, the switching process (i.e., alternately connecting and disconnecting the load and buffer capacitor) can be initiated by receiving a corresponding command from the NFC-enabled device using near-field communication. For this purpose, logic circuit 21 (see...) Figure 5 It can be configured to communicate with NFC-enabled devices using known near-field communication technologies.

[0033] Another embodiment relates to a passive system including an electrical load (e.g., an electromechanical actuator) and an energy harvesting circuit configured to harvest ambient energy and use the harvested ambient energy to charge a buffer capacitor (see [link to relevant documentation]). Figure 1 and Figure 5 The system also includes control circuitry configured to alternately connect and disconnect the electrical load and the buffer capacitor, such that during a discharge phase (where the electrical load is connected to the buffer capacitor and the capacitor voltage decreases), the capacitor voltage supplied by the buffer capacitor is applied to the electrical load, and during a charging phase, the buffer capacitor is recharged, in which the electrical load is disconnected from the buffer capacitor. The durations of the charging and discharging phases are designed such that the capacitor voltage remains above a minimum supply voltage of the electrical load (see [reference]). Figure 3 Minimum supply voltage V STOP ).

[0034] In one example, the control circuitry includes a transistor H-bridge. However, depending on the specific application, a single transistor or any other type of electronic switch may suffice. The control circuitry may include logic circuitry (including a driver circuitry system) configured to generate control signals for the transistors used to connect and disconnect the load and buffer capacitor. As mentioned, the control logic may also be able to communicate with NFC-enabled devices using near-field communication.

[0035] Although the invention has been shown and described with respect to one or more implementations, changes and / or modifications may be made to the illustrated examples without departing from the spirit and scope of the appended claims. In particular, with respect to the various functions performed by the components or structures (units, assemblies, devices, circuits, systems, etc.) described above, unless otherwise indicated, the terminology used to describe such components (including references to “devices”) is intended to correspond to any component or structure that performs the specified function of the described component (e.g., functionally equivalent), even if it is not structurally equivalent to the disclosed structure that performs the function in the exemplary implementations of the invention shown herein.

Claims

1. A system for operating an electromechanical lock, comprising: An energy harvesting circuit that operates to collect ambient energy and use the collected ambient energy to charge a buffer capacitor; A control circuit, operated by periodically switching on and off, alternately i) connects the motor to the buffer capacitor during a discharge phase to move the latch of the electromechanical lock, and ii) disconnects the motor from the buffer capacitor during a charging phase. The process involves alternately connecting and disconnecting the motor until the motor's output power reaches the desired target level, or until the nth discharge stage ends, where n is a predetermined number. The duration of the charging and discharging phases is controlled such that the capacitor voltage of the buffer capacitor is kept higher than the minimum supply voltage required to operate the motor to move the latch. The periodic on / off control includes implementing multiple on / off control cycles; Wherein, for each of the plurality of on / off control cycles, the control circuit operates to: i) activate the switching circuit to the on state for the on portion of each on / off control cycle to transmit the capacitor voltage to the motor, and ii) deactivate the switching circuit to the off state for the off portion of each on / off control cycle to prevent the capacitor voltage from being transmitted to the motor; During the on-state portion of each on / off control cycle, the amplitude of the capacitor voltage stored in the capacitor is controlled to be greater than the minimum supply voltage; and During the disconnection portion of each on / off control cycle, the amplitude of the capacitor voltage stored in the capacitor is greater than the minimum supply voltage.

2. The system according to claim 1, in, During the discharge phase, the capacitor voltage provided by the buffer capacitor decreases while being applied to the motor to supply power to the motor, and During the charging phase, the capacitor voltage increases.

3. The system according to claim 1, further comprising: Mobile devices that can support Near Field Communication (NFC) are configured to generate an electromagnetic field. The energy harvesting circuit includes an NFC antenna.

4. The system according to claim 1, in, The control circuit includes a transistor H-bridge.

5. The system according to claim 1, in, In order to alternately connect the motor and the buffer capacitor and disconnect the motor from the buffer capacitor, the control circuit operates to: i) connect the motor to the buffer capacitor when the capacitor voltage reaches an upper threshold voltage level, and ii) disconnect the motor from the buffer capacitor when the capacitor voltage drops to a lower threshold voltage level.

6. The system according to claim 1, in, In order to alternately connect the motor and the buffer capacitor and disconnect the motor from the buffer capacitor, the control circuit operates to: i) connect the motor to the buffer capacitor when the capacitor voltage reaches an upper threshold voltage level, and ii) disconnect the motor from the buffer capacitor after a predetermined time.

7. The system according to claim 1, in, The electric motor has a higher power consumption than the average power provided by the energy harvesting circuit.

8. The system according to claim 1, in, The minimum supply voltage is the magnitude of the supply voltage required by the motor to rotate and move the latch.

9. A method for operating an electromechanical lock, the method comprising: An energy harvesting circuit is used to collect ambient energy and the collected ambient energy is used to charge a buffer capacitor with a capacitor voltage. The motor is alternately connected to the buffer capacitor during the discharge phase and disconnected from the buffer capacitor during the charging phase by periodically switching the circuit on / off. Specifically, the process involves alternately connecting the motor and the buffer capacitor, and then disconnecting the motor from the buffer capacitor, until the output power of the motor reaches the desired target level, or until the nth discharge stage ends, where n is a predetermined number; and The duration of the charging and discharging phases is controlled such that the capacitor voltage remains higher than the minimum supply voltage of the motor, thereby causing the motor to move the latch of the electromechanical lock. The periodic on / off control includes implementing multiple on / off control cycles, and the method includes: i) for the on portion of each on / off control cycle, activating the switching circuit to the on state to transmit the capacitor voltage to the motor, and ii) for the off portion of each on / off control cycle, deactivating the switching circuit to the off state to prevent the capacitor voltage from being transmitted to the motor; During the on-state portion of each on / off control cycle, the amplitude of the capacitor voltage stored in the capacitor is controlled to be greater than the minimum supply voltage; and During the disconnection portion of each on / off control cycle, the amplitude of the capacitor voltage stored in the capacitor is greater than the minimum supply voltage.

10. The method according to claim 9, in, During the discharge phase, the capacitor voltage provided by the buffer capacitor decreases while being applied to the motor; as well as During the charging phase, the capacitor voltage increases again.

11. The method according to claim 9, in, The ambient energy is the energy of the electromagnetic field generated by a communication device that supports wireless communication.

12. The method according to claim 9, in, The ambient energy is the energy of the electromagnetic field generated by the device supporting near-field communication.

13. The method according to claim 9, wherein, Alternatingly connecting the motor and the buffer capacitor and disconnecting the motor from the buffer capacitor includes: When the capacitor voltage reaches the upper threshold voltage level, the motor is connected to the buffer capacitor to apply the capacitor voltage to the motor, and When the capacitor voltage drops to the lower threshold voltage level, the motor is disconnected from the buffer capacitor.

14. The method according to claim 9, wherein, Alternatingly connecting the motor and the buffer capacitor and disconnecting the motor from the buffer capacitor includes: When the capacitor voltage reaches the upper threshold voltage level, the motor is connected to the buffer capacitor to apply the capacitor voltage to the motor. The duration of the discharge phase is a predetermined time.

15. The method according to claim 9, in, The electric motor has a higher power consumption than the average power supplied to the buffer capacitor by the energy harvesting circuit.

16. The method according to claim 9, in, The minimum supply voltage is the supply voltage required by the motor to rotate and move the latch.

17. A control device, comprising: Wireless receiver hardware, which operates to wirelessly receive energy and store the received energy in an energy storage device to generate a power supply voltage; as well as The controller, whose operation is used for: i) Monitor the amplitude of the supply voltage stored in the energy storage device; as well as ii) During the periodic on / off control of supplying power from the supply voltage to the mechanical load, prevent the amplitude of the supply voltage from falling below a voltage threshold level and prevent the amplitude of the supply voltage applied to the mechanical load from exceeding the voltage threshold level, so as to cause physical movement of the mechanical load; Wherein, the voltage threshold level is the first voltage threshold level; The energy storage device is a capacitor; The periodic on / off control includes implementing multiple on / off control cycles; Wherein, for each of the plurality of on / off control cycles, the controller operates to: i) activate the switching circuit to the on state for the on portion of each on / off control cycle to transmit the supply voltage to the mechanical load; and ii) deactivate the switching circuit to the off state for the off portion of each on / off control cycle to prevent the supply voltage from being transmitted to the mechanical load; During the on-state portion of each on / off control cycle, the amplitude of the supply voltage stored in the capacitor is controlled to be greater than the first voltage threshold level; and During the disconnection portion of each on / off control cycle, the amplitude of the supply voltage stored in the capacitor is greater than the first voltage threshold level.

18. The control device according to claim 17, wherein the periodic on / off control comprises: During the first part of each control cycle of the periodic on / off control, the energy storage device is charged by the received energy, while the energy storage device is electrically disconnected from the mechanical load. as well as During the second part of each control cycle of the periodic on / off control, the energy storage device is discharged while the energy storage device is electrically connected to supply power to the mechanical load.

19. The control device of claim 17, wherein the physical movement of the mechanical load stops when the amplitude of the supply voltage is below the voltage threshold level.

20. The control device of claim 17, wherein the mechanical load requires the supply voltage to be higher than the voltage threshold level to cause physical movement of the mechanical load.

21. The control device of claim 17, wherein the amplitude of the supply voltage stored in the capacitor decreases during the on-state portion of each on / off control cycle; and in, The magnitude of the supply voltage stored in the capacitor increases during the disconnection portion of each on / off control cycle.

22. The control device of claim 17, wherein periodic on / off control of supplying power from the power supply voltage to the mechanical load in multiple cycles increases the output power of the mechanical load to a desired target level.

23. The control device of claim 17, wherein periodic on / off control of supplying power from the power supply voltage to the mechanical load in multiple cycles generates progressive output power of the mechanical load.

24. The control device of claim 23, wherein the progressive output power results in an angular displacement of the mechanical load.

25. The control device of claim 23, wherein the output power of the mechanical load: i) increases in each of a plurality of discharge stages in which the supply voltage is applied to the mechanical load, and ii) does not increase in each of a plurality of discharge stages in which the supply voltage is not applied to the mechanical load.

26. The control device of claim 17, wherein the wireless receiver hardware is configured to receive a wireless command instructing control of the mechanical load; and The controller operation is used to implement the wireless commands.

27. The control device of claim 17, wherein periodic on / off control of supplying power from the power supply voltage to the mechanical load causes the energy storage device to charge and discharge.

28. The control device of claim 17, wherein periodic on / off control of power supplied from the supply voltage to the mechanical load causes intermittent movement of the mechanical load.

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