A vibration energy harvesting circuit, device and system having multiple maximum power tracking modes

Abstract

The present disclosure relates to the field of vibration energy harvesting, and particularly relates to a vibration energy harvesting circuit, device and system with multiple maximum power tracking modes, the multiple maximum power tracking modes including an open-circuit voltage mode and a configuration resistance mode, the circuit comprising: a rectifier circuit connected to a vibration generator, a first output end outputting a first voltage, and a second output end grounded; an impedance adjustable circuit, a first input end connected to the first output end of the rectifier circuit via a first switch, and a second input end grounded; a bleeder resistance and a second switch connected in series between the first output end of the rectifier circuit and the ground; a configuration resistance and a third switch connected in series between the first output end of the rectifier circuit and the ground; a voltage acquisition module; a maximum power tracking controller for controlling the impedance of the impedance adjustable circuit; and a charging circuit connected to a first output end of the impedance adjustable circuit. The vibration energy harvesting scheme of the present disclosure is suitable for different vibration generators, thereby expanding its application range.

Description

Technical Field

[0001] This disclosure relates to the field of vibration energy harvesting systems, and more specifically to a vibration energy harvesting circuit, device, and system with multiple maximum power tracking modes. Background Technology

[0002] With the widespread adoption of intelligent devices, the use of sensors is increasing, highlighting the growing issues of power consumption and power supply. The limitations of chemical batteries, such as limited energy storage capacity, short lifespan requiring periodic replacement, and environmental unfriendliness, have led to a desire to find an alternative power supply method.

[0003] Vibration energy harvesting systems are a novel power supply method with broad application prospects, playing a crucial role in powering low-power electronic devices such as sensors. These systems employ self-harvesting technology, converting minute energy sources in the environment into electrical energy to power low-power sensors. This approach offers advantages such as being environmentally friendly and easy to maintain. Vibration energy is a ubiquitous form of environmental energy, found in sources like airflow, water flow, and machine vibration. Collecting these minute vibrations, converting and storing them through micro-energy management, and then using this energy to power low-power devices is increasingly becoming a solution for powering such devices.

[0004] Because vibration energy in the environment is highly random and lacks continuity, vibration energy harvesting systems need to fully utilize the vibration energy present in the environment. Therefore, maximum power point tracking (MPPT) technology for vibration energy harvesting is receiving increasing attention. MPPT is a technique that dynamically adjusts system parameters to ensure the vibration energy harvesting system always operates at maximum power output. Its core objective is to optimize energy conversion efficiency in complex and variable vibration environments. However, existing MPPT modes are limited and have poor adaptability to different vibration generators, severely restricting the widespread application of vibration energy harvesting systems. Summary of the Invention

[0005] To address the problems in the related technologies, embodiments of this disclosure provide a vibration energy harvesting circuit, device, and system with multiple maximum power tracking modes.

[0006] In a first aspect, this disclosure provides a vibration energy harvesting circuit with multiple maximum power point tracking (MPPT) modes, characterized in that the multiple MPPT modes include an open-circuit voltage mode and a configured resistor mode, and the vibration energy harvesting circuit includes:

[0007] A rectifier circuit is connected to a vibration generator to convert the AC power output by the vibration generator into DC power and output it through a first output terminal and a second output terminal. The first output terminal of the rectifier circuit outputs a first voltage Vin, and the second output terminal is grounded. An impedance-adjustable circuit is provided, wherein the first input terminal of the impedance-adjustable circuit is connected to the first output terminal of the rectifier circuit via a first switch, the second input terminal of the impedance-adjustable circuit is grounded, the first output terminal of the impedance-adjustable circuit is connected to the charging circuit, and the second output terminal of the impedance-adjustable circuit is grounded. A bleed resistor and a second switch are connected in series between the first output terminal of the rectifier circuit and ground. A resistor and a third switch are configured to be connected in series between the first output terminal of the rectifier circuit and ground. Voltage acquisition module; Maximum power point tracking controller; A charging circuit, connected to the first output terminal of the impedance-adjustable circuit, is used to charge the energy storage element using the second voltage Vout output from the first output terminal of the impedance-adjustable circuit. in: In open-circuit voltage mode, the third switch remains open, and the first and second switches are alternately opened and closed. When the first switch is open and the second switch is closed, the voltage acquisition module acquires the voltage Vr of the bleeder resistor and outputs the maximum power voltage Vmpp calculated based on the voltage Vr of the bleeder resistor as the reference voltage Vref of the maximum power point tracking controller. When the first switch is closed and the second switch is open, the maximum power point tracking controller controls the impedance of the impedance-adjustable circuit based on the reference voltage Vref and the preset charging voltage Vset, so as to control the first voltage Vin near the reference voltage Vref and the second voltage Vout near the preset charging voltage Vset. In the configuration resistor mode, the second switch remains open, and the first and third switches are alternately opened and closed. When the first switch is open and the third switch is closed, the voltage acquisition module acquires the voltage of the configuration resistor and outputs the voltage of the configuration resistor as the reference voltage Vref of the maximum power point tracking controller. When the first switch is closed and the third switch is open, the maximum power point tracking controller controls the impedance of the impedance-adjustable circuit according to the reference voltage Vref and the preset charging voltage Vset, so as to control the first voltage Vin near the reference voltage Vref and control the value of the second voltage Vout near the preset charging voltage Vset.

[0008] According to an embodiment of this disclosure, in open-circuit voltage mode, the maximum power voltage Vmpp is calculated based on the voltage Vr of the bleeder resistor, the resistance RL of the bleeder resistor, the internal resistance R1 of the vibration generator, and a preset proportionality coefficient A between the maximum power voltage and the open-circuit voltage.

[0009] According to embodiments of this disclosure, the internal resistance R1 of the vibration generator is determined in the following manner: Disconnect the first switch and the second switch, and obtain the value Vo1 of the first voltage Vin; Keep the first switch open, close the second switch, and obtain the value of the first voltage Vin, Vr1. Calculate the internal resistance R1 of the vibration generator based on RL, Vo1, and Vr1.

[0010] According to an embodiment of this disclosure, the resistance value of the configuration resistor is the load resistance value corresponding to the maximum output power in the relationship curve between the output power of the vibration generator and the load resistance value.

[0011] According to an embodiment of this disclosure, the charging circuit is connected to the output terminal of the impedance-adjustable circuit via a fourth switch, and the vibration energy harvesting circuit further includes: An energy storage controller is used to monitor the power level of the energy storage element. When the power level is lower than the lower limit, it controls the fourth switch to close so that the energy storage element is charged through the charging circuit. When the power level is higher than the upper limit, it controls the fourth switch to open so that the charging of the energy storage element through the charging circuit is stopped.

[0012] According to embodiments of this disclosure, it further includes an energy storage configuration module for providing a preset charging voltage Vset to the maximum power point tracking controller via the energy storage controller.

[0013] According to embodiments of this disclosure, a maximum power point tracking (MPPT) mode configuration module is also included for configuring the current MPPT mode.

[0014] According to embodiments of this disclosure, when the energy storage element's charge is lower than the mode switching threshold, the maximum power point tracking (MPPT) configuration module configures the MPPT mode to a matched resistor mode; when the energy storage element's charge is not lower than the mode switching threshold, the MPPT configuration module configures the MPPT mode to an open-circuit voltage mode.

[0015] According to embodiments of this disclosure, the maximum power point tracking controller includes: The first voltage comparator is used to generate a first comparison waveform PWM1 of the reference voltage Vref and the first voltage Vin; The second voltage comparator is used to generate a second comparison waveform PWM2 of the preset charging voltage Vset and the second voltage Vout; The control module is used to generate an impedance control signal for the impedance-adjustable circuit based on the first comparison waveform and the second comparison waveform, and to control the impedance of the impedance-adjustable circuit.

[0016] According to embodiments of this disclosure, the impedance-adjustable circuit includes: An inductor, wherein a first end of the inductor is connected to a first input terminal of an impedance-adjustable circuit, a second end of the inductor is connected to a second terminal of the impedance-adjustable circuit via a fifth switch, and a first output terminal of the impedance-adjustable circuit via a sixth switch; A capacitor, wherein a first end of the capacitor is connected to a first output terminal of an impedance-adjustable circuit, and a second end of the capacitor is connected to a second output terminal of the impedance-adjustable circuit.

[0017] According to embodiments of this disclosure, the impedance control signal for the impedance-adjustable circuit is generated in the following manner: Monitor the first comparison waveform PWM1; When the first comparison waveform PWM1 has a rising edge, the rising edge of PWM1 is taken as the first rising edge. The time T0 between the first rising edge of the first comparison waveform PWM1 and the first falling edge after the first rising edge is obtained. The time T3 between the first rising edge of PWM1 and the second rising edge after the first rising edge is obtained. The high-level duration T1 of the second comparison waveform PWM2 during T3 is obtained. The high-level duration T2 and low-level duration T4 of the impedance control signal are calculated using the following formula:

[0018]

[0019] Where S and K are preset coefficients, Based on the waveform of the impedance control signal PWM3 generated by T2 and T4, during T2, the fifth switch is closed and the sixth switch is open, and during T4, the fifth switch is open and the sixth switch is closed.

[0020] According to embodiments of this disclosure, the maximum power point tracking (MPPT) configuration module is further configured to configure the ratio of the maximum power voltage to the open-circuit voltage and the resistance value of the resistor.

[0021] The second aspect of this disclosure provides a vibration energy harvesting device with multiple maximum power tracking modes, characterized in that it includes a vibration energy harvesting circuit according to any one of the first aspects of this disclosure.

[0022] A third aspect of this disclosure provides a vibration energy harvesting system with multiple maximum power point tracking modes, characterized in that it includes a vibration energy harvesting circuit according to any one of the first aspects of this disclosure, and further includes the vibration generator and / or the energy storage element.

[0023] Compared with the prior art, the beneficial effects of this disclosure are as follows: The vibration energy acquisition system according to embodiments of this disclosure can be configured into open-circuit voltage mode and configuration resistor mode via a maximum power point tracking (MPPT) mode configuration module. Different MPPT modes are applicable to different vibration generators, thus improving the applicability of the vibration energy acquisition scheme. In open-circuit voltage mode, the maximum power voltage is calculated by measuring the voltage across the bleeder resistor, avoiding interference caused by frequent load disconnection during open-circuit voltage measurement in traditional open-circuit voltage mode. For different vibration generators, the voltage acquisition module can use different preset proportional coefficients A when calculating the maximum power voltage, thereby achieving adaptation to different vibration generators.

[0024] This disclosure innovatively proposes an intelligent mode switching mechanism, achieving dynamic optimization of energy capture and storage through dual-mode collaboration of open-circuit voltage mode and matched-resistance mode. Compared to open-circuit voltage mode, matched-resistance mode offers faster charging speeds but causes greater losses to circuit components. The vibration energy harvesting scheme according to this disclosure automatically sets the operating mode through a maximum power point tracking (MPPT) configuration module. When the energy storage element's charge level is below the mode switching threshold, it automatically switches to matched-resistance mode; when the energy storage element's charge level is not below the mode switching threshold, it automatically switches to open-circuit voltage mode.

[0025] Furthermore, at the energy storage element level, embodiments of this disclosure can be configured with various energy storage parameter configuration schemes, improving the system's adaptability to different energy storage elements. During system initialization, the energy storage configuration module configures the charging mode, charging parameters, and energy storage element voltage threshold parameters, making the vibration energy harvesting system applicable to various energy storage elements, such as lithium-ion batteries, nickel-metal hydride batteries, lithium iron phosphate batteries, supercapacitors, and solid-state batteries, thereby improving the lifespan and safety of the energy storage elements. Compared to existing technologies, this disclosure shows particularly significant improvements in overall energy efficiency under intermittent vibration and variable amplitude conditions, providing an innovative solution for the sustainable power supply of low-power devices.

[0026] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0027] Other features, objects, and advantages of this disclosure will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings: Figure 1A circuit diagram of a vibration energy harvesting circuit according to an embodiment of the present disclosure is shown.

[0028] Figure 2 A rectifier circuit according to an embodiment of the present disclosure is shown.

[0029] Figure 3 An exemplary curve showing the relationship between the output power P of the vibration generator and the load resistance value R is shown.

[0030] Figure 4 A schematic diagram of a maximum power point tracking controller according to an embodiment of the present disclosure is shown.

[0031] Figure 5 A circuit diagram of a vibration energy harvesting circuit according to an embodiment of the present disclosure is shown, illustrating the structure of a rectifier circuit and an impedance-adjustable circuit.

[0032] Figure 6 The connection relationships between the maximum power point tracking controller and the components in the impedance-adjustable circuit are shown.

[0033] Figure 7 A schematic diagram is shown showing the principle of generating an impedance control signal based on a first comparison waveform and a second comparison waveform. Detailed Implementation

[0034] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement them. Furthermore, for clarity, portions unrelated to the description of exemplary embodiments have been omitted from the drawings.

[0035] In this disclosure, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of features, figures, steps, behaviors, components, parts or combinations thereof disclosed in this specification, and are not intended to exclude the possibility of the presence or addition of one or more other features, figures, steps, behaviors, components, parts or combinations thereof.

[0036] It should also be noted that, unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other. This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] As mentioned earlier, the existing maximum power tracking mode for vibration energy is singular and has poor adaptability to different vibration generators, which seriously limits the promotion and application of vibration energy acquisition systems.

[0038] To address the aforementioned technical problems, this invention discloses a vibration energy harvesting circuit, device, and system with multiple maximum power point tracking (MPPT) modes, including an open-circuit voltage mode and a configured resistor mode. The vibration energy harvesting circuit includes: A rectifier circuit is connected to a vibration generator to convert the AC power output by the vibration generator into DC power and output it through a first output terminal and a second output terminal. The first output terminal of the rectifier circuit outputs a first voltage Vin, and the second output terminal is grounded. An impedance-adjustable circuit is provided, wherein the first input terminal of the impedance-adjustable circuit is connected to the first output terminal of the rectifier circuit via a first switch, the second input terminal of the impedance-adjustable circuit is grounded, the first output terminal of the impedance-adjustable circuit is connected to the charging circuit, and the second output terminal of the impedance-adjustable circuit is grounded. A bleed resistor and a second switch are connected in series between the first output terminal of the rectifier circuit and ground. A resistor and a third switch are configured to be connected in series between the first output terminal of the rectifier circuit and ground. Voltage acquisition module; Maximum power point tracking controller; A charging circuit, connected to the first output terminal of the impedance-adjustable circuit, is used to charge the energy storage element using the second voltage Vout output from the first output terminal of the impedance-adjustable circuit. in: In open-circuit voltage mode, the third switch remains open, and the first and second switches are alternately opened and closed. When the first switch is open and the second switch is closed, the voltage acquisition module acquires the voltage Vr of the bleeder resistor and outputs the maximum power voltage Vmpp calculated based on the voltage Vr of the bleeder resistor as the reference voltage Vref of the maximum power point tracking controller. When the first switch is closed and the second switch is open, the maximum power point tracking controller controls the impedance of the impedance-adjustable circuit based on the reference voltage Vref and the preset charging voltage Vset, so as to control the first voltage Vin near the reference voltage Vref and the second voltage Vout near the preset charging voltage Vset. In the configuration resistor mode, the second switch remains open, and the first and third switches are alternately opened and closed. When the first switch is open and the third switch is closed, the voltage acquisition module acquires the voltage of the configuration resistor and outputs the voltage of the configuration resistor as the reference voltage Vref of the maximum power point tracking controller. When the first switch is closed and the third switch is open, the maximum power point tracking controller controls the impedance of the impedance-adjustable circuit according to the reference voltage Vref and the preset charging voltage Vset, so as to control the first voltage Vin near the reference voltage Vref and control the value of the second voltage Vout near the preset charging voltage Vset.

[0039] The vibration energy harvesting circuit according to embodiments of this disclosure can be configured into open-circuit voltage mode and configuration resistor mode via a maximum power point tracking (MPPT) mode configuration module. Different MPPT modes are applicable to different vibration generators, thus improving the application range of the vibration energy harvesting circuit. In open-circuit voltage mode, the maximum power voltage is calculated by measuring the voltage across the bleeder resistor, avoiding interference caused by frequent load disconnection during open-circuit voltage measurement in traditional open-circuit voltage mode. For different vibration generators, the voltage acquisition module can use different preset proportional coefficients A when calculating the maximum power voltage, thereby achieving adaptation to different vibration generators.

[0040] The following is for reference. Figure 1 and Figure 2 A vibration energy harvesting circuit with multiple maximum power point tracking modes according to embodiments of the present disclosure will be described in detail.

[0041] like Figure 1 and Figure 2 As shown, the vibration energy acquisition circuit according to an embodiment of this disclosure includes: a rectifier circuit, an impedance adjustable circuit, a bleeder resistor RL, a configuration resistor R, a voltage acquisition module, a maximum power point tracking controller, a charging circuit, a first switch M1, a second switch M2, and a third switch M3.

[0042] like Figure 1 As shown, the two input terminals of the rectifier circuit are connected to the two output terminals of the vibration generator, respectively, to convert the AC power from the vibration generator into DC power. The first output terminal of the rectifier circuit outputs a first voltage Vin, and the second output terminal is grounded.

[0043] Figure 2 A rectifier circuit according to an embodiment of the present disclosure is shown.

[0044] like Figure 2 As shown, in one implementation, the rectifier circuit includes a first rectifier diode D1, a second rectifier diode D2, a third rectifier diode D3, a fourth rectifier diode D4, and a rectifier circuit buffer capacitor C. The anodes of the first and third rectifier diodes are connected to the first output terminal of the vibration generator; the anodes of the second and fourth rectifier diodes are connected to the second output terminal of the vibration generator; the cathodes of the first and second rectifier diodes are connected to the first output terminal of the rectifier circuit; and the anodes of the third and fourth rectifier diodes are connected to the second output terminal of the rectifier circuit. The rectifier circuit buffer capacitor is connected between the first and second output terminals of the rectifier circuit to stabilize the DC voltage output by the rectifier circuit. It can be understood that... Figure 2 The rectifier circuit shown is merely an example; those skilled in the art can use other rectifier circuits to achieve AC-DC conversion as needed.

[0045] like Figure 1 As shown, the first input terminal of the impedance-adjustable circuit is connected to the first output terminal of the rectifier circuit via a first switch M1, and the second input terminal of the impedance-adjustable circuit is grounded. A bleeder resistor RL and a second switch M2 are connected in series between the first output terminal of the rectifier circuit and ground. A configuration resistor R and a third switch M3 are connected in series between the first output terminal of the rectifier circuit and ground.

[0046] The charging circuit is connected to the first output terminal of the impedance-adjustable circuit and is used to charge the energy storage element using the second voltage Vout output from the first output terminal of the impedance-adjustable circuit.

[0047] According to embodiments of this disclosure, different operating modes are achieved by controlling the switches in the vibration energy harvesting circuit through a maximum power point tracking controller.

[0048] According to embodiments of this disclosure, in open-circuit voltage mode, the third switch remains open, while the first and second switches are alternately opened and closed. When the first switch is open and the second switch is closed, the voltage acquisition module acquires the voltage Vr of the bleeder resistor RL and outputs the maximum power voltage Vmpp calculated based on the voltage Vr of the bleeder resistor as the reference voltage Vref of the maximum power point tracking controller. When the first switch is closed and the second switch is open, the maximum power point tracking controller controls the impedance of the impedance-adjustable circuit based on the reference voltage Vref and the preset charging voltage Vset, so as to control the first voltage Vin near the reference voltage Vref and the second voltage Vout near the preset charging voltage Vset.

[0049] According to an embodiment of this disclosure, in open-circuit voltage mode, the maximum power voltage Vmpp is calculated based on the voltage Vr of the bleeder resistor, the resistance RL of the bleeder resistor, the internal resistance R1 of the vibration generator, and a preset proportionality coefficient A between the maximum power voltage and the open-circuit voltage.

[0050] According to an embodiment of this disclosure, the internal resistance R1 of the vibration generator is determined by: disconnecting the first switch and the second switch, obtaining the value Vo1 of the first voltage Vin; keeping the first switch open, closing the second switch, obtaining the value Vr1 of the first voltage Vin; and calculating the internal resistance R1 of the vibration generator based on RL, Vo1, and Vr1.

[0051] Vibratory generators typically harvest energy from vibrational sources in the external environment. If the load is completely disconnected when sampling open-circuit voltage, the load on a magnetic coil-type vibratory generator will suddenly change, affecting the generator's output voltage and current. This may cause the generator to experience resistance in the opposite direction, a phenomenon known as the "generator braking effect" or "load resistance." This resistance is transmitted to the vibration source, causing changes in the source's own vibration. Therefore, frequent open-circuit voltage sampling can introduce interference to the vibration source, with a more pronounced effect on sources with weak vibrations.

[0052] To reduce the interference caused to the vibration source by frequent open-circuit voltage acquisition, the open-circuit voltage mode of this embodiment uses a bleed resistor RL as a temporary load during open-circuit voltage acquisition, thereby avoiding the situation where the load is completely disconnected during open-circuit voltage acquisition. The specific working principle is as follows: When initially acquiring the open-circuit voltage, the maximum power point tracking controller disconnects the first switch M1 and the second switch M2, and acquires the open-circuit voltage Vo1 through the voltage acquisition module. Then, the second switch M2 is closed, and the bleeder resistor RL is connected. The voltage acquisition module then acquires the voltage Vr1 across RL after connecting the bleeder resistor RL. Since RL, Vo1, and Vr1 are all known, the internal resistance R1 of the vibration generator can be calculated using the following formula based on the principle of resistor voltage division.

[0053]

[0054]

[0055] When acquiring the open-circuit voltage later, the maximum power point tracking controller disconnects the first switch M1 and closes the second switch M2. By acquiring the voltage Vr across the bleeder resistor RL after it is connected, the open-circuit voltage Vo can be calculated. This technical solution avoids the load surge problem caused by completely disconnecting the load.

[0056]

[0057] After calculating the open-circuit voltage Vo, the maximum power voltage Vmpp = A can be calculated based on the preset proportionality coefficient A between the maximum power voltage and the open-circuit voltage. Because different vibration generators have different power generation principles, their maximum power voltage to open-circuit voltage ratio A is also different. This disclosure provides multiple different ratios A, using different ratios A to calculate the maximum power voltage for different vibration generators, thereby adapting to various types of vibration generators.

[0058] In the configuration resistor mode, the second switch remains open, and the first and third switches are alternately opened and closed. When the first switch is open and the third switch is closed, the voltage acquisition module acquires the voltage of the configuration resistor and outputs the voltage of the configuration resistor as the reference voltage Vref of the maximum power point tracking controller. When the first switch is closed and the third switch is open, the maximum power point tracking controller controls the impedance of the impedance-adjustable circuit according to the reference voltage Vref and the preset charging voltage Vset, so as to control the first voltage Vin near the reference voltage Vref and the second voltage Vout near the preset charging voltage Vset.

[0059] According to an embodiment of this disclosure, the resistance value of the configuration resistor is the load resistance value corresponding to the maximum output power in the relationship curve between the output power of the vibration generator and the load resistance value.

[0060] Figure 3 An exemplary curve showing the relationship between the output power P of the vibration generator and the load resistance value R is shown.

[0061] like Figure 3 As shown, the configuration resistor value is taken as the load resistance value R(Pmax) corresponding to the maximum output power Pmax of the vibration generator. R(Pmax) may differ for different vibration generators; therefore, the configuration resistor in this embodiment can have an adjustable resistance value, using a corresponding resistance value for different vibration generators. By controlling the resistance value of the impedance-adjustable circuit to keep the first voltage Vin near the reference voltage Vref, the resistance value of the impedance-adjustable circuit can be stabilized near R(Pmax), thereby achieving maximum power point tracking (MPPT) of the vibration generator.

[0062] According to an embodiment of this disclosure, the charging circuit is connected to the output of the impedance-adjustable circuit via a fourth switch M4, thereby charging the energy storage element using the second voltage Vout output by the impedance-adjustable circuit.

[0063] According to an embodiment of this disclosure, the vibration energy harvesting circuit further includes an energy storage controller for monitoring the power of the energy storage element. When the power is lower than the lower limit, the controller closes the fourth switch to charge the energy storage element through the charging circuit. When the power is higher than the upper limit, the controller opens the fourth switch to stop charging the energy storage element through the charging circuit.

[0064] According to embodiments of this disclosure, the vibration energy harvesting circuit further includes an energy storage configuration module for providing a preset charging voltage Vset to the maximum power point tracking controller via the energy storage controller.

[0065] According to embodiments of this disclosure, controlling the first voltage Vin to be near a reference voltage Vref means controlling the first voltage Vin to be within a first specified range near the reference voltage Vref, and controlling the value of the second voltage Vout to be near a preset charging voltage Vset means controlling the value of the second voltage Vout to be within a second specified range near the preset charging voltage Vset.

[0066] According to embodiments of this disclosure, the vibration energy harvesting circuit further includes a maximum power point tracking (MPPT) mode configuration module for configuring the current MPPT mode.

[0067] This disclosure innovatively proposes an intelligent mode switching mechanism, achieving dynamic optimization of energy capture and storage through dual-mode collaboration of open-circuit voltage mode and matched-resistance mode. Compared to open-circuit voltage mode, matched-resistance mode offers faster charging speeds but causes greater losses to circuit components. The vibration energy harvesting circuit according to this disclosure automatically sets its operating mode via a maximum power point tracking (MPPT) configuration module. The energy storage controller monitors the charge level of the energy storage element. When the energy storage element's charge level falls below the mode switching threshold, it automatically switches to matched-resistance mode; when the energy storage element's charge level is not lower than the mode switching threshold, it automatically switches to open-circuit voltage mode.

[0068] Figure 4 A schematic diagram of a maximum power tracking controller according to an embodiment of the present disclosure is shown.

[0069] According to embodiments of this disclosure, the maximum power point tracking controller includes: The first voltage comparator is used to generate a first comparison waveform PWM1 of the reference voltage Vref and the first voltage Vin; The second voltage comparator is used to generate a second comparison waveform PWM2 of the preset charging voltage Vset and the second voltage Vout; The control module is used to generate an impedance control signal for the impedance-adjustable circuit based on the first comparison waveform and the second comparison waveform, and to control the impedance of the impedance-adjustable circuit.

[0070] Figure 5 A circuit diagram of a vibration energy harvesting circuit according to an embodiment of the present disclosure is shown, illustrating the structure of a rectifier circuit and an impedance-adjustable circuit.

[0071] According to an embodiment of this disclosure, the impedance-adjustable circuit includes: an inductor L1, the first end of which is connected to a first input terminal of the impedance-adjustable circuit, the second end of which is connected to a second terminal of the impedance-adjustable circuit via a fifth switch M5 and to a first output terminal of the impedance-adjustable circuit via a sixth switch M6; and a capacitor C1, the first end of which is connected to the first output terminal of the impedance-adjustable circuit, and the second end of which is connected to a second output terminal of the impedance-adjustable circuit.

[0072] Figure 6 The connection relationships between the maximum power point tracking controller and the components in the impedance-adjustable circuit are shown. Figure 7 A schematic diagram is shown showing the principle of generating an impedance control signal based on a first comparison waveform and a second comparison waveform.

[0073] like Figure 6 and Figure 7 As shown, according to an embodiment of this disclosure, the impedance control signal of the impedance-adjustable circuit is generated in the following manner: monitoring a first comparison waveform PWM1; when a rising edge occurs in the first comparison waveform PWM1, taking the rising edge of PWM1 as the first rising edge, obtaining the time T0 between the first rising edge of the first comparison waveform PWM1 and the first falling edge after the first rising edge, obtaining the time T3 between the first rising edge of PWM1 and the second rising edge after the first rising edge, obtaining the high-level duration T1 of the second comparison waveform PWM2 during T3; calculating the high-level duration T2 and the low-level duration T4 of the impedance control signal using the following formulas:

[0074]

[0075] Where S and K are preset coefficients, which can be determined according to the actual load of the circuit. Based on T2 and T4, the waveform of the impedance control signal PWM3 is generated. During T2, the fifth switch is closed and the sixth switch is open. During T4, the fifth switch is open and the sixth switch is closed.

[0076] According to embodiments of this disclosure, the maximum power point tracking (MPPT) configuration module is further configured to configure the ratio of the maximum power voltage to the open-circuit voltage and the resistance value of the resistor.

[0077] This disclosure also provides a vibration energy harvesting device with multiple maximum power point tracking modes, characterized in that it includes a vibration energy harvesting circuit according to any one of the first aspects of this disclosure.

[0078] This disclosure also provides a vibration energy harvesting system with multiple maximum power point tracking modes, characterized in that it includes a vibration energy harvesting circuit according to any one of the first aspects of this disclosure, and further includes the vibration generator and / or the energy storage element.

[0079] The embodiments of this disclosure achieve real-time tracking of Vin to Vref through a first voltage comparator, establish a forced locking of the vibration source impedance matching, and construct an input closed loop; at the same time, the input impedance is optimized by using a preset configuration resistor value to cope with different vibration intensities; the second voltage comparator maintains the dynamic balance between Vout and Vset to ensure that the energy storage voltage is in the optimized operating range, and constructs an output closed loop. The synergistic effect of the two loops enables the circuit to maintain a stable operating point even under severe vibration fluctuations, overcoming the impedance mismatch problem under weak vibration conditions.

[0080] The embodiments disclosed herein optimize impedance matching during the energy capture stage using intelligent mode switching (open-circuit voltage / matching resistor mode), addressing the front-end energy conversion efficiency issues caused by changes in vibration source characteristics. The energy storage switch control logic focuses on energy management during the storage stage, triggering charging / discharging state switching via a voltage threshold to prevent circuit efficiency degradation due to overvoltage of the energy storage element. These two components form a closed-loop "capture-storage" dual-stage control: when the energy storage element's charge reaches the threshold, charging is disconnected to protect the energy storage element and indirectly optimize the front-end operating point by cutting off the downstream load. This composite control strategy successfully overcomes the technical bottleneck of the fragmented "capture-storage" stage in traditional solutions: maintaining high-precision open-circuit detection when the energy storage element has sufficient charge, and automatically activating the configuration resistor mode to enhance energy capture when the voltage drops. Seamless switching between the two is achieved through the energy storage voltage threshold, constructing a hybrid maximum power point tracking system with environmental adaptability. Compared to existing technologies, this solution shows particularly significant improvements in overall energy efficiency under intermittent vibration and complex operating conditions, providing an innovative solution for the sustainable power supply of vibration-generated power generation equipment.

[0081] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features disclosed in this disclosure that have similar functions.

Claims

1. A vibration energy harvesting circuit with multiple maximum power point tracking modes, characterized in that, The multiple maximum power point tracking modes include open-circuit voltage mode and configured resistor mode, and the vibration energy harvesting circuit includes: A rectifier circuit is connected to a vibration generator and is used to convert the AC power output by the vibration generator into DC power and output it through a first output terminal and a second output terminal. The first output terminal of the rectifier circuit outputs a first voltage Vin, and the second output terminal is grounded. An impedance-adjustable circuit is provided, wherein the first input terminal of the impedance-adjustable circuit is connected to the first output terminal of the rectifier circuit via a first switch, the second input terminal of the impedance-adjustable circuit is grounded, the first output terminal of the impedance-adjustable circuit is connected to the charging circuit, and the second output terminal of the impedance-adjustable circuit is grounded. A bleed resistor and a second switch are connected in series between the first output terminal of the rectifier circuit and ground. A resistor and a third switch are configured to be connected in series between the first output terminal of the rectifier circuit and ground. Voltage acquisition module; Maximum power point tracking controller; A charging circuit, connected to the first output terminal of the impedance-adjustable circuit, is used to charge the energy storage element using the second voltage Vout output from the first output terminal of the impedance-adjustable circuit. in: In open-circuit voltage mode, the third switch remains open, and the first and second switches are alternately opened and closed. When the first switch is open and the second switch is closed, the voltage acquisition module acquires the voltage Vr of the bleeder resistor and outputs the maximum power voltage Vmpp calculated based on the voltage Vr of the bleeder resistor as the reference voltage Vref of the maximum power point tracking controller. When the first switch is closed and the second switch is open, the maximum power point tracking controller controls the impedance of the impedance-adjustable circuit based on the reference voltage Vref and the preset charging voltage Vset, so as to control the first voltage Vin near the reference voltage Vref and the second voltage Vout near the preset charging voltage Vset. In the configuration resistor mode, the second switch remains open, and the first and third switches are alternately opened and closed. When the first switch is open and the third switch is closed, the voltage acquisition module acquires the voltage of the configuration resistor and outputs the voltage of the configuration resistor as the reference voltage Vref of the maximum power point tracking controller. When the first switch is closed and the third switch is open, the maximum power point tracking controller controls the impedance of the impedance-adjustable circuit according to the reference voltage Vref and the preset charging voltage Vset, so as to control the first voltage Vin near the reference voltage Vref and control the value of the second voltage Vout near the preset charging voltage Vset.

2. The vibration energy harvesting circuit according to claim 1, characterized in that, In open-circuit voltage mode, the maximum power voltage Vmpp is calculated based on the voltage Vr of the bleeder resistor, the resistance RL of the bleeder resistor, the internal resistance R1 of the vibration generator, and the preset proportionality coefficient A between the maximum power voltage and the open-circuit voltage.

3. The vibration energy harvesting circuit according to claim 2, characterized in that, The internal resistance R1 of the vibration generator is determined in the following way: Disconnect the first switch and the second switch, and obtain the value Vo1 of the first voltage Vin; Keep the first switch open, close the second switch, and obtain the value of the first voltage Vin, Vr1. Calculate the internal resistance R1 of the vibration generator based on RL, Vo1, and Vr1.

4. The vibration energy harvesting circuit according to claim 1, characterized in that, The resistance value of the configured resistor is the load resistance value corresponding to the maximum output power in the curve relating the output power of the vibration generator to the load resistance value.

5. The vibration energy harvesting circuit according to claim 1, characterized in that, The charging circuit is connected to the output terminal of the impedance-adjustable circuit via a fourth switch, and the vibration energy harvesting circuit further includes: An energy storage controller is used to monitor the power level of the energy storage element. When the power level is lower than the lower limit, it controls the fourth switch to close so that the energy storage element is charged through the charging circuit. When the power level is higher than the upper limit, it controls the fourth switch to open so that the charging of the energy storage element through the charging circuit is stopped.

6. The vibration energy harvesting circuit according to claim 5, characterized in that, It also includes an energy storage configuration module for providing a preset charging voltage Vset to the maximum power point tracking controller through the energy storage controller.

7. The vibration energy harvesting circuit according to claim 1, characterized in that, It also includes a maximum power point tracking (MPPT) mode configuration module, which is used to configure the current maximum power point tracking mode.

8. The vibration energy harvesting circuit according to claim 7, characterized in that, When the energy storage element's charge is lower than the mode switching threshold, the maximum power point tracking (MPPT) configuration module configures the MPPT mode to the matched resistor mode. When the energy storage element's charge is not lower than the mode switching threshold, the MPPT configuration module configures the MPPT mode to the open-circuit voltage mode.

9. The vibration energy harvesting circuit according to claim 1, characterized in that, The maximum power point tracking controller includes: The first voltage comparator is used to generate a first comparison waveform PWM1 of the reference voltage Vref and the first voltage Vin; The second voltage comparator is used to generate a second comparison waveform PWM2 of the preset charging voltage Vset and the second voltage Vout; The control module is used to generate an impedance control signal for the impedance-adjustable circuit based on the first comparison waveform and the second comparison waveform, and to control the impedance of the impedance-adjustable circuit.

10. The vibration energy harvesting circuit according to claim 9, characterized in that, The impedance-adjustable circuit includes: An inductor, wherein a first end of the inductor is connected to a first input terminal of an impedance-adjustable circuit, a second end of the inductor is connected to a second terminal of the impedance-adjustable circuit via a fifth switch, and a first output terminal of the impedance-adjustable circuit via a sixth switch; A capacitor, wherein a first end of the capacitor is connected to a first output terminal of an impedance-adjustable circuit, and a second end of the capacitor is connected to a second output terminal of the impedance-adjustable circuit.

11. The vibration energy harvesting circuit according to claim 10, characterized in that, The impedance control signal for the impedance-adjustable circuit is generated in the following way: Monitor the first comparison waveform PWM1; When the first comparison waveform PWM1 has a rising edge, the rising edge of PWM1 is taken as the first rising edge. The time T0 between the first rising edge of the first comparison waveform PWM1 and the first falling edge after the first rising edge is obtained. The time T3 between the first rising edge of PWM1 and the second rising edge after the first rising edge is obtained. The high-level duration T1 of the second comparison waveform PWM2 during T3 is obtained. The high-level duration T2 and low-level duration T4 of the impedance control signal are calculated using the following formula: Where S and K are preset coefficients, Based on the waveform of the impedance control signal PWM3 generated by T2 and T4, during T2, the fifth switch is closed and the sixth switch is open, and during T4, the fifth switch is open and the sixth switch is closed.

12. The vibration energy harvesting circuit according to claim 7, characterized in that, The maximum power point tracking (MPPT) configuration module is also used to configure the ratio of the maximum power voltage to the open-circuit voltage and to configure the resistance value of the resistor.

13. A vibration energy harvesting device with multiple maximum power point tracking modes, characterized in that, Includes a vibration energy harvesting circuit according to any one of claims 1-12.

14. A vibration energy harvesting system with multiple maximum power point tracking modes, characterized in that, The device includes the vibration energy harvesting circuit according to any one of claims 1-12, and further includes the vibration generator and / or the energy storage element.

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