An adaptive maximum power point tracking system for an energy harvesting system

Abstract

The present application relates to the technical fields of energy collection, and especially to an adaptive maximum power point tracking system of an energy collection system, comprising an electromagnetic vibration energy collection device for collecting environmental vibration energy and converting the collected environmental vibration energy into an alternating voltage for output; an H-type rectifier circuit for converting the alternating voltage into a direct current voltage for output; a power management circuit for performing step-up and step-down conversion on the direct current voltage and converting the direct current voltage into a usable output voltage for output; a measurement signal circuit for measuring the current output by the power management circuit and outputting a filtered voltage signal according to the measured current, and for setting a vibration sensor to sense the changes in environmental vibration in real time and feed the change signal to a microcontroller, so that the microcontroller adjusts the disturbance step length and the disturbance period according to the environmental vibration parameters, and enables the system to track the maximum power point when the vibration environment of the power transmission line changes dramatically.

Description

Technical Field

[0001] This invention relates to the field of energy harvesting technology, and in particular to an adaptive maximum power point tracking system for energy harvesting systems. Background Technology

[0002] In recent years, the rapid development of radio communication and integrated circuit technologies has led to the widespread application of various sensors on power transmission lines to monitor the safe and stable operation of power systems. However, the chemical batteries that power these sensors have problems such as limited lifespan, difficulty in replacement, and environmental pollution. Directly drawing power from power transmission lines through methods such as capacitive voltage division and current inductance is also unreliable, as direct contact with the power grid can affect the operational safety of transmission lines and is not suitable for high-voltage direct current transmission lines.

[0003] Against this backdrop, capturing distributed energy from the environment and providing autonomous power for sensors has become a promising solution, including thermal, solar, wind, magnetic field, and vibration energy. Compared to solar, wind, and thermal energy, which are commonly found in the environment, vibration energy is less affected by natural factors such as weather changes and is widely present in the environment. Therefore, electromagnetic vibration energy harvesting has broad application prospects in powering sensors in power transmission lines.

[0004] Electromagnetic vibration energy harvesting systems typically consist of an electromagnetic vibration energy harvester and a power conversion circuit. The vibration energy harvester converts the collected vibration energy into alternating current (AC) power, which is then converted by the power conversion circuit to provide DC power to the sensor. To achieve efficient power transmission and maximize the utilization of even small vibration energy from the environment, the power conversion circuit must be regulated using a maximum power point tracking (MPPT) algorithm. To achieve MPPT, impedance matching must be implemented between the electromagnetic vibration energy harvester and the power conversion circuit to ensure it always operates at its maximum output power point. However, in power transmission line applications, the vibration environment is constantly changing, leading to MPPT drift and posing challenges to maximum power transmission.

[0005] Based on the above conditions, real-time tracking of the changing maximum power point becomes the key to solving the problem. To this end, an adaptive maximum power point tracking system for energy harvesting systems is proposed. Summary of the Invention

[0006] Therefore, the technical problem to be solved by this invention is: how to track the changing maximum power point in real time.

[0007] The above-mentioned technical problems are solved by the following technical solution: This invention proposes an adaptive maximum power point tracking system for energy harvesting systems, comprising, An electromagnetic vibration energy harvesting device is used to collect environmental vibration energy and convert the collected environmental vibration energy into AC voltage for output. An H-type rectifier circuit is used to convert AC voltage into DC voltage for output. The power management circuit is used to convert DC voltage into a step-up / step-down voltage and then output a usable output voltage. A measurement signal circuit is used to measure the current output by the power management circuit and output a filtered voltage signal based on the measured current. A microcontroller is used to control the power management circuit to perform maximum power point tracking of the DC voltage; A vibration sensor is used to sense changes in the environment and feed back the frequency and amplitude signals of the changes to the microcontroller. The microcontroller applies a perturbation to the duty cycle of the power management circuit based on perceived environmental changes, and determines the direction of the next perturbation by comparing the changes in the voltage signal before and after the perturbation, so that the operating point approaches the maximum power point.

[0008] In a preferred embodiment of the adaptive maximum power point tracking system of the energy harvesting system described in this invention, a filter capacitor is further included, which is used to filter the DC voltage output by the H-type rectifier circuit.

[0009] In a preferred embodiment of the adaptive maximum power point tracking system of the energy harvesting system of the present invention, it further includes an energy storage battery for storing the output voltage of the power management circuit.

[0010] In a preferred embodiment of the adaptive maximum power point tracking system of the energy harvesting system of the present invention: the electromagnetic vibration energy harvesting device has a positive output terminal and a negative output terminal, and the positive output terminal and the negative output terminal of the electromagnetic vibration energy harvesting device are used to output AC voltage; The H-type rectifier circuit has a first input terminal, a second input terminal, a first output terminal, and a second output terminal; The power management circuit has a first input terminal, a second input terminal, a third input terminal, a first output terminal, and a second output terminal; The measurement signal circuit has a first input terminal, a second input terminal, a first output terminal, and a second output terminal; The microcontroller includes a control circuit, which has a first input terminal and a first output terminal. The vibration sensor has a first input terminal and a first output terminal; The positive output terminal of the electromagnetic vibration energy harvesting device is connected to the first input terminal of the H-type rectifier circuit, and the negative output terminal of the electromagnetic vibration energy harvesting device is connected to the second input terminal of the H-type rectifier circuit. The first output terminal of the H-type rectifier circuit is connected to the first input terminal of the power management circuit via the filter capacitor, and the second output terminal of the H-type rectifier circuit is connected to the second input terminal of the power management circuit via the filter capacitor. The first output terminal of the power management circuit is connected to the positive terminal of the energy storage battery and the first input terminal of the vibration sensor. The negative terminal of the energy storage battery is connected to the first input terminal and the second input terminal of the measurement signal circuit. The first output terminal of the measurement signal circuit is connected to the second output terminal of the power management circuit. The second output terminal of the measurement signal circuit is connected to the first output terminal of the vibration sensor and the first input terminal of the microcontroller. The first output terminal of the microcontroller is connected to the third input terminal of the power management circuit.

[0011] In a preferred embodiment of the adaptive maximum power point tracking system of the energy harvesting system of the present invention: the H-type rectifier circuit includes a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, and a fourth NMOS transistor; The source of the first NMOS transistor is connected to the drain of the third NMOS transistor, and the connection point is the first input terminal of the H-type rectifier circuit. The drain of the first NMOS transistor is connected to the drain of the second NMOS transistor, and the connection point is the first output terminal of the H-type rectifier circuit; The first output terminal of the H-type rectifier circuit is connected to the positive terminal of the filter capacitor; The source of the second NMOS transistor is connected to the drain of the fourth NMOS transistor, and the connection point is the second input terminal of the H-type rectifier circuit; The source of the third NMOS transistor is connected to the source of the fourth NMOS transistor, and the connection point is the second output terminal of the H-type rectifier circuit. The second output terminal of the H-type rectifier circuit is connected to the negative terminal of the filter capacitor.

[0012] In a preferred embodiment of the adaptive maximum power point tracking system of the energy harvesting system of the present invention: the power management circuit can perform step-up / step-down conversion on the DC voltage output after processing by the filter capacitor; When the environment changes slowly and the vibration energy is weak, the duty cycle of the main switch of the power management circuit is adjusted so that the power management circuit is in a boost state, and the DC voltage is boosted to charge the energy storage battery. When the environment vibrates violently and the collected vibration energy is strong, the duty cycle of the main switch of the power management circuit is adjusted to put the power management circuit into a step-down state, and the DC voltage is stepped down to charge the energy storage battery.

[0013] In a preferred embodiment of the adaptive maximum power point tracking system of the energy harvesting system of the present invention: the measurement signal circuit includes a measurement resistor, a feedback resistor, a feedback capacitor, and an operational amplifier; The current output by the power management circuit flows through the energy storage battery and is then input to the signal measurement circuit. After flowing through the measurement resistor, it forms a measurement voltage. After being filtered by the feedback resistor and the feedback capacitor, the signal is amplified by the operational amplifier and then output as a DC measurement voltage signal. The DC measurement voltage signal is input to the microcontroller through the first input terminal of the microcontroller.

[0014] In a preferred embodiment of the adaptive maximum power point tracking system of the energy harvesting system described in this invention, the step of approximating the operating point to the maximum power point includes: Calculate the internal impedance of the electromagnetic vibration energy harvesting device; The equivalent input resistance of the connected circuit is calculated based on the DC voltage. Sensing environmental change data and setting disturbance factors based on the environmental change data; Adjust the duty cycle of the main switch of the power management circuit according to the disturbance factors to match the internal impedance and the equivalent input resistance. Compare the changes in the voltage signal before and after the disturbance, and determine the direction of the next disturbance based on the changes in the voltage signal, so that the operating point approaches the maximum power point; The disturbance factors include the disturbance step size and the disturbance period.

[0015] In a preferred embodiment of the adaptive maximum power point tracking system of the energy harvesting system described in this invention: the step of setting the disturbance factor based on environmental change data includes: The microcontroller determines the maximum vibration energy value of the electromagnetic vibration energy harvesting device under the current environment based on the environmental vibration parameters fed back by the vibration sensor. The initial step size is calculated based on the maximum vibration energy value, equivalent input resistance, and internal impedance. The actual perturbation step size is set to be greater than the initial step size, and maintains a fixed proportional relationship with the initial step size; The microcontroller analyzes the settling time required for the system to reach stability after a duty cycle disturbance based on the power management circuit. The disturbance period is set to be longer than the settling time, and maintains a fixed proportional relationship with the settling time; In response to the vibration sensor detecting a change in environmental vibration parameters, the microcontroller recalculates the initial step size and the settling time, and updates the disturbance step size and the disturbance period accordingly.

[0016] In a preferred embodiment of the adaptive maximum power point tracking system of the energy harvesting system described in this invention: the step of determining the next perturbation direction based on the change in the voltage signal includes: The microcontroller samples the voltage signal during each disturbance cycle and calculates the current output power based on the voltage signal; Compare the current output power with the power recorded in the previous disturbance cycle; If the current output power is greater than the power recorded in the previous disturbance cycle, then the direction of the next disturbance is the same as the direction of the current disturbance. If the current output power is less than the power recorded in the previous disturbance cycle, the direction of the next disturbance will be opposite to the direction of the current disturbance. If the current output power is equal to the power recorded in the previous disturbance cycle, the disturbance direction is maintained or randomly changed. Update the duty cycle based on the determined perturbation direction and the perturbation step size.

[0017] The beneficial effects of this invention are as follows: by setting up a vibration sensor, the changes in environmental vibration are sensed in real time, and the change signal is fed back to the microcontroller. The microcontroller adjusts the disturbance step size and disturbance period according to the environmental vibration parameters, so that the system can still track the maximum power point when the vibration environment of the transmission line changes drastically. This overcomes the problem of tracking failure or low efficiency caused by the fixed step size and fixed sampling period in the traditional disturbance observation method. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0019] Figure 1 The system framework diagram of the adaptive maximum power point tracking system of the energy harvesting system is shown.

[0020] Figure 2 The circuit diagram of the adaptive maximum power point tracking system of the energy harvesting system is shown.

[0021] Figure 3 The diagram shows the measurement signal circuit structure of the adaptive maximum power point tracking system for an energy harvesting system.

[0022] Figure 4 The tracking flowchart of the adaptive maximum power point tracking system for the energy harvesting system is shown. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0024] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0025] Reference Figure 1 This embodiment provides an adaptive maximum power point tracking system for an energy harvesting system, including, Electromagnetic vibration energy harvesting device 1 is used to collect environmental vibration energy and convert the collected environmental vibration energy into AC voltage for output; H-type rectifier circuit 2 is used to convert AC voltage into DC voltage for output; Power management circuit 3 is used to convert DC voltage into a step-up / step-down voltage and output it as a usable output voltage. Power management circuit 3 is a Buck-Boost power management circuit, which converts DC voltage into an output voltage usable by the sensor.

[0026] The measurement signal circuit 4 is used to measure the current output by the power management circuit 3 and output a filtered voltage signal based on the measured current. Microcontroller 5 is used to control the power management circuit 3 to perform maximum power point tracking of DC voltage; A vibration sensor is used to sense changes in the environment and feed back the frequency and amplitude signals of the changes to the microcontroller 5. The microcontroller 5 applies a disturbance to the duty cycle of the power management circuit 3 based on the perceived environmental changes, and determines the direction of the next disturbance by comparing the changes in the voltage signal before and after the disturbance, so that the operating point approaches the maximum power point.

[0027] As an optional embodiment, a filter capacitor is also included, which is used to filter the DC voltage output by the H-type rectifier circuit 2.

[0028] As an optional embodiment, it also includes an energy storage battery for storing the output voltage of the power management circuit 3.

[0029] For example, refer to Figure 2 The electromagnetic vibration energy harvesting device 1 has a positive output terminal and a negative output terminal, and the positive output terminal and the negative output terminal of the electromagnetic vibration energy harvesting device 1 are used to output AC voltage. The H-type rectifier circuit 2 has a first input terminal, a second input terminal, a first output terminal, and a second output terminal; The power management circuit 3 has a first input terminal, a second input terminal, a third input terminal, a first output terminal, and a second output terminal; The measurement signal circuit 4 has a first input terminal, a second input terminal, a first output terminal, and a second output terminal; The microcontroller 5 includes a control circuit, which has a first input terminal and a first output terminal; The vibration sensor has a first input terminal and a first output terminal; The positive output terminal of the electromagnetic vibration energy harvesting device 1 is connected to the first input terminal of the H-type rectifier circuit 2, and the negative output terminal of the electromagnetic vibration energy harvesting device 1 is connected to the second input terminal of the H-type rectifier circuit 2. The first output terminal of the H-type rectifier circuit 2 is connected to the first input terminal of the power management circuit 3 after passing through a filter capacitor, and the second output terminal of the H-type rectifier circuit 2 is connected to the second input terminal of the power management circuit 3 after passing through a filter capacitor. The first output terminal of the power management circuit 3 is connected to the positive terminal of the energy storage battery and the first input terminal of the vibration sensor. The negative terminal of the energy storage battery is connected to the first input terminal and the second input terminal of the measurement signal circuit. The first output terminal of the measurement signal circuit 4 is connected to the second output terminal of the power management circuit 3. The second output terminal of the measurement signal circuit 4 is connected to the first output terminal of the vibration sensor and the first input terminal of the microcontroller 5. The first output terminal of the microcontroller 5 is connected to the third input terminal of the power management circuit 3.

[0030] As an optional embodiment: the H-type rectifier circuit 2 includes a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, and a fourth NMOS transistor; The source of the first NMOS transistor is connected to the drain of the third NMOS transistor, and the connection point is the first input terminal of the H-type rectifier circuit 2. The drain of the first NMOS transistor is connected to the drain of the second NMOS transistor, and the connection point is the first output terminal of the H-type rectifier circuit 2. The first output terminal of the H-type rectifier circuit 2 is connected to the positive terminal of the filter capacitor; The source of the second NMOS transistor is connected to the drain of the fourth NMOS transistor, and the connection point is the second input terminal of the H-type rectifier circuit. The source of the third NMOS transistor is connected to the source of the fourth NMOS transistor, and the connection point is the second output terminal of the H-type rectifier circuit. The second output terminal of the H-type rectifier circuit 2 is connected to the negative terminal of the filter capacitor.

[0031] As an optional embodiment: the power management circuit 3 can perform step-up / step-down conversion on the DC voltage output after processing by the filter capacitor; When the environment changes slowly and the vibration energy is weak, the duty cycle of the main switch of the power management circuit 3 is adjusted so that the power management circuit 3 is in a boost state, and the DC voltage is boosted to charge the energy storage battery. When the environment vibrates violently and the collected vibration energy is strong, the duty cycle of the main switch of the power management circuit 3 is adjusted so that the power management circuit 3 is in a step-down state, and the DC voltage is stepped down to charge the energy storage battery.

[0032] Reference Figure 3 As an optional embodiment: the measurement signal circuit 4 includes a measurement resistor, a feedback resistor, a feedback capacitor, and an operational amplifier; Figure 3 In this context, the measured resistance is expressed as... The feedback resistor is expressed as The feedback capacitor is represented as .

[0033] The current output from the power management circuit 3 flows through the energy storage battery and is then input to the signal measurement circuit 4. After flowing through the measurement resistor, it forms a measurement voltage. After being filtered by the feedback resistor and feedback capacitor, the signal is amplified by the operational amplifier and then output as a DC measurement voltage signal. The DC measurement voltage signal is input to the microcontroller 5 through the first input terminal of the microcontroller.

[0034] Reference Figure 4 In one alternative embodiment, the step of approximating the operating point to the maximum power point includes: Step S1: Calculate the internal impedance of the electromagnetic vibration energy harvesting device 1; Specifically, the formula (1) for calculating the internal impedance is: (1) in: (2) in, Indicates internal impedance. and As shown in formula (2), The equivalent resistance of the electromagnetic vibration energy harvesting device 1 is... The equivalent inductance of the electromagnetic vibration energy harvesting device 1 is... It is the imaginary unit. The angular frequency of the transmission line vibration. The equivalent capacitance of the electromagnetic vibration energy harvesting device 1 is... The coil resistance of the electromagnetic vibration energy harvesting device 1 The coil inductance is for the electromagnetic vibration energy harvesting device 1.

[0035] Step S2: Calculate the equivalent input resistance of the subsequent circuit based on the DC voltage; whereby the equivalent input resistance of the subsequent circuit refers to all components connected to the DC output terminal of the H-type rectifier bridge.

[0036] Specifically, the formula (3) for calculating the equivalent input resistance is: (3) in, Indicates the equivalent input resistance. DC voltage This represents the equivalent input resistance under DC voltage. and It can be derived from formula (1), where in formula (1) and All are plural numbers. and These are defined as the real and imaginary parts of the complex impedance, respectively, where: This is the equivalent resistance, which is the real part of the complex impedance; The equivalent reactance belongs to the imaginary part of the complex impedance, in formula (3) The magnitude of the complex impedance is represented by , where .

[0037] Furthermore, since the vibration amplitude varies considerably in the working environment of transmission lines, the maximum vibration acceleration is denoted as... , Let be the maximum vibrational energy collected, as shown in formula (4). The mass of the permanent magnet in the electromagnetic vibration energy harvesting device. The electromechanical coupling coefficient of electromagnetic vibration energy harvesting device 1 is given. This is the angular frequency of the transmission line vibration.

[0038] The formula (4) for calculating the maximum vibration energy is as follows: (4) Step S3: Sensing environmental change data and setting disturbance factors based on the environmental change data; The disturbance factors include the disturbance step size and the disturbance period; The steps for setting disturbance factors based on environmental change data include: Step S31: The microcontroller 5 determines the maximum vibration energy value of the electromagnetic vibration energy harvesting device 1 under the current environment based on the environmental vibration parameters fed back by the vibration sensor; Among them, environmental vibration parameters include the maximum vibration acceleration and the angular frequency of transmission line vibration.

[0039] Step S32: Calculate the initial step size based on the maximum vibration energy value, equivalent input resistance, and internal impedance; It should be noted that since the AC voltage output by the electromagnetic vibration energy harvesting device 1 changes during operation, the DC voltage also changes. As the DC voltage changes, the output power of the power management circuit 3 also changes, and it has a maximum value. At the maximum power point, that is, when the DC voltage is 1, the maximum output power is calculated using formula (5): (5) in, This indicates the maximum output power. Indicates the maximum vibration acceleration. This represents the angular frequency of the transmission line vibration. This represents the DC voltage at the maximum power point. This represents the maximum vibration energy value. Represented as equivalent resistance, it belongs to the real part of the complex impedance. It is expressed as equivalent reactance and belongs to the imaginary part of complex impedance.

[0040] The initial step size is calculated using formula (6): (6) in, Indicates the initial step size. This represents the DC voltage at the maximum power point. Indicates the output voltage. This represents the maximum vibration energy value. Indicates the maximum vibration acceleration. This represents the angular frequency of the transmission line vibration. Indicates the equivalent input resistance. This represents the change in equivalent input resistance. Represented as equivalent resistance, it belongs to the real part of the complex impedance. It is represented as equivalent reactance.

[0041] Step S33: Set the actual perturbation step size to be greater than the initial step size, and maintain a fixed proportional relationship with the initial step size; In this embodiment, the perturbation step size should also be chosen appropriately; it should not be too large or too small. If the perturbation step size is too large, although the system response will be fast enough, the accuracy in finding the maximum power point will be greatly reduced, the output voltage will oscillate violently, and the system will be in a state of deviating from the maximum power point for a long time, which will also reduce the power extraction efficiency. If the perturbation step size is too small, that is, the step size each time is too small, the process of finding the maximum power point will be very slow, which will also cause energy waste and prevent the system from tracking the maximum power point quickly and in a timely manner, leading to algorithm failure. The preferred perturbation step size is 1.1 times the initial step size of the system, that is... ,in, Indicates the perturbation step size. This indicates the initial step size.

[0042] Step S34: The microcontroller 5 analyzes the settling time required for the system to reach stability after the duty cycle disturbance based on the power management circuit 3; Step S35: Set the disturbance period to be greater than the settling time and maintain a fixed proportional relationship with the settling time; Let the settling time be denoted as The disturbance period is set to The disturbance period should not be too large or too small. While adhering to the basic principle of ensuring the microcontroller 5 does not malfunction, if the sampling time is too large, although it ensures the system reaches steady state each time, the dynamic response speed will be significantly slowed down. If the input environment changes, the system will need a long time to find the new maximum power point through step-by-step disturbances, failing to track changes in the optimal value in a timely manner, thus wasting energy. If the sampling time is too small, the next sampling will occur before the system reaches steady state, resulting in inaccurate power values. The microcontroller 5 may make incorrect disturbance direction judgments based on erroneous feedback. The preferred sampling time is 1.25 times the system settling time. =1.25 .

[0043] Step S36: In response to the vibration sensor detecting a change in the environmental vibration parameters, the microcontroller 5 recalculates the initial step size and settling time, and updates the disturbance step size and disturbance period accordingly.

[0044] Step S4: Adjust the duty cycle of the main switch of the power management circuit 3 according to the disturbance factors so that the internal impedance and the equivalent input resistance are matched; by matching the two, the power can be increased.

[0045] Step S5: Compare the changes in voltage signals before and after the disturbance, and determine the direction of the next disturbance based on the changes in voltage signals, so that the operating point approaches the maximum power point; The steps for determining the direction of the next disturbance based on changes in the voltage signal include: Step S51: Microcontroller 5 samples the voltage signal in each disturbance cycle and calculates the current output power based on the voltage signal; Step S52: Compare the current output power with the power recorded in the previous disturbance cycle; If the current output power is greater than the power recorded in the previous disturbance cycle, then the direction of the next disturbance is the same as the direction of the current disturbance. If the current output power is less than the power recorded in the previous disturbance cycle, the direction of the next disturbance will be opposite to the direction of the current disturbance. If the current output power is equal to the power recorded in the previous disturbance cycle, the disturbance direction is maintained or randomly changed. Step S53: Update the duty cycle based on the determined perturbation direction and perturbation step size.

[0046] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. An adaptive maximum power point tracking system for an energy harvesting system, characterized in that: include, Electromagnetic vibration energy harvesting device (1), which is used to collect environmental vibration energy and convert the collected environmental vibration energy into AC voltage for output; H-type rectifier circuit (2), which is used to convert AC voltage into DC voltage for output; The power management circuit (3) is used to convert DC voltage into a step-up / step-down voltage and output it as a usable output voltage. The measurement signal circuit (4) is used to measure the current output by the power management circuit (3) and output a filtered voltage signal based on the measured current. The microcontroller (5) is used to control the power management circuit (3) to perform maximum power point tracking on the DC voltage; A vibration sensor is used to sense environmental changes and feed back the frequency and amplitude signals of the changes to the microcontroller (5). The microcontroller (5) applies a disturbance to the duty cycle of the power management circuit (3) based on the perceived environmental changes, and determines the next disturbance direction by comparing the changes in the voltage signal before and after the disturbance, so that the operating point approaches the maximum power point.

2. The adaptive maximum power point tracking system for the energy harvesting system according to claim 1, characterized in that: It also includes a filter capacitor, which is used to filter the DC voltage output by the H-type rectifier circuit (2).

3. The adaptive maximum power point tracking system for the energy harvesting system according to claim 2, characterized in that: It also includes an energy storage battery, which is used to store the output voltage of the power management circuit (3).

4. The adaptive maximum power point tracking system for the energy harvesting system according to claim 3, characterized in that: The electromagnetic vibration energy harvesting device (1) has a positive output terminal and a negative output terminal, and the positive output terminal and the negative output terminal of the electromagnetic vibration energy harvesting device (1) are used to output AC voltage. The H-type rectifier circuit (2) has a first input terminal, a second input terminal, a first output terminal, and a second output terminal; The power management circuit (3) has a first input terminal, a second input terminal, a third input terminal, a first output terminal, and a second output terminal; The measurement signal circuit (4) has a first input terminal, a second input terminal, a first output terminal, and a second output terminal; The microcontroller (5) includes a control circuit, which has a first input terminal and a first output terminal; The vibration sensor has a first input terminal and a first output terminal; The positive output terminal of the electromagnetic vibration energy harvesting device (1) is connected to the first input terminal of the H-type rectifier circuit (2), and the negative output terminal of the electromagnetic vibration energy harvesting device (1) is connected to the second input terminal of the H-type rectifier circuit (2). The first output terminal of the H-type rectifier circuit (2) is connected to the first input terminal of the power management circuit (3) after passing through the filter capacitor, and the second output terminal of the H-type rectifier circuit (2) is connected to the second input terminal of the power management circuit (3) after passing through the filter capacitor. The first output terminal of the power management circuit (3) is connected to the positive terminal of the energy storage battery and the first input terminal of the vibration sensor; The negative terminal of the energy storage battery is connected to the first input terminal and the second input terminal of the measurement signal circuit. The first output terminal of the measurement signal circuit (4) is connected to the second output terminal of the power management circuit (3). The second output terminal of the measurement signal circuit (4) is connected to the first output terminal of the vibration sensor and the first input terminal of the microcontroller (5). The first output terminal of the microcontroller (5) is connected to the third input terminal of the power management circuit (3).

5. The adaptive maximum power point tracking system for the energy harvesting system according to claim 4, characterized in that: The H-type rectifier circuit (2) includes a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, and a fourth NMOS transistor; The source of the first NMOS transistor is connected to the drain of the third NMOS transistor, and the connection point is the first input terminal of the H-type rectifier circuit (2); The drain of the first NMOS transistor is connected to the drain of the second NMOS transistor, and the connection point is the first output terminal of the H-type rectifier circuit (2); The first output terminal of the H-type rectifier circuit (2) is connected to the positive terminal of the filter capacitor; The source of the second NMOS transistor is connected to the drain of the fourth NMOS transistor, and the connection point is the second input terminal of the H-type rectifier circuit; The source of the third NMOS transistor is connected to the source of the fourth NMOS transistor, and the connection point is the second output terminal of the H-type rectifier circuit. The second output terminal of the H-type rectifier circuit (2) is connected to the negative terminal of the filter capacitor.

6. The adaptive maximum power point tracking system for the energy harvesting system according to claim 5, characterized in that: The power management circuit (3) can perform step-up / step-down conversion on the DC voltage output after processing by the filter capacitor; When the environment changes slowly and the vibration energy is weak, the duty cycle of the main switch of the power management circuit (3) is adjusted so that the power management circuit (3) is in a boost state, and the DC voltage is boosted to charge the energy storage battery. When the environment vibrates violently and the collected vibration energy is strong, the duty cycle of the main switch of the power management circuit (3) is adjusted so that the power management circuit (3) is in a step-down state, and the DC voltage is stepped down to charge the energy storage battery.

7. The adaptive maximum power point tracking system for the energy harvesting system according to claim 6, characterized in that: The measurement signal circuit (4) includes a measurement resistor, a feedback resistor, a feedback capacitor, and an operational amplifier; The current output by the power management circuit (3) flows through the energy storage battery and is then input to the signal measurement circuit (4). After flowing through the measurement resistor, it forms a measurement voltage. After being filtered by the feedback resistor and the feedback capacitor, the signal is amplified by the operational amplifier and then output as a DC measurement voltage signal. The DC measurement voltage signal is input to the microcontroller (5) through the first input terminal of the microcontroller.

8. The adaptive maximum power point tracking system for the energy harvesting system according to any one of claims 1 to 7, characterized in that, The steps to bring the operating point closer to the maximum power point include: Calculate the internal impedance of the electromagnetic vibration energy harvesting device (1); The equivalent input resistance of the connected circuit is calculated based on the DC voltage. Sensing environmental change data and setting disturbance factors based on the environmental change data; Adjust the duty cycle of the main switch of the power management circuit (3) according to the disturbance factors so that the internal impedance and the equivalent input resistance are matched. Compare the changes in the voltage signal before and after the disturbance, and determine the direction of the next disturbance based on the changes in the voltage signal, so that the operating point approaches the maximum power point; The disturbance factors include the disturbance step size and the disturbance period.

9. The adaptive maximum power point tracking system for an energy harvesting system according to claim 8, characterized in that, The step of setting disturbance factors based on environmental change data includes: The microcontroller (5) determines the maximum vibration energy value of the electromagnetic vibration energy harvesting device (1) under the current environment based on the environmental vibration parameters fed back by the vibration sensor. The initial step size is calculated based on the maximum vibration energy value, equivalent input resistance, and internal impedance. The actual perturbation step size is set to be greater than the initial step size, and maintains a fixed proportional relationship with the initial step size; The microcontroller (5) analyzes the settling time required for the system to reach stability after the duty cycle disturbance based on the power management circuit (3); The disturbance period is set to be longer than the settling time, and maintains a fixed proportional relationship with the settling time; When the vibration sensor detects a change in the environmental vibration parameters, the microcontroller (5) recalculates the initial step size and the settling time, and updates the disturbance step size and the disturbance period accordingly.

10. The adaptive maximum power point tracking system for the energy harvesting system according to claim 9, characterized in that, The step of determining the direction of the next disturbance based on the change in the voltage signal includes: The microcontroller (5) samples the voltage signal in each disturbance cycle and calculates the current output power based on the voltage signal; Compare the current output power with the power recorded in the previous disturbance cycle; If the current output power is greater than the power recorded in the previous disturbance cycle, then the direction of the next disturbance is the same as the direction of the current disturbance. If the current output power is less than the power recorded in the previous disturbance cycle, the direction of the next disturbance will be opposite to the direction of the current disturbance. If the current output power is equal to the power recorded in the previous disturbance cycle, the disturbance direction is maintained or randomly changed. Update the duty cycle based on the determined perturbation direction and the perturbation step size.

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