MPPT (Maximum Power Point Tracking) system for collecting thermoelectric energy
By setting up a thermocouple and amplification circuit on the thermoelectric module, combining the BOOST circuit and voltage monitor, the voltage of the thermoelectric module is controlled by using the pulse width modulation signal to track it to the maximum power point, and the energy conversion efficiency of the existing thermoelectric energy acquisition system is solved. and the problem of insufficient utilization rate, efficient energy collection and utilization is achieved.
Patent Information
- Application Number
- CN202421113063.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2025-02-25
- Estimated Expiration
- 2034-05-21
AI Technical Summary
The existing thermoelectric energy acquisition systems have shortcomings in energy conversion efficiency and energy utilization. Traditional MPPT systems need to disconnect the circuit to measure open circuit voltage, resulting in waste of energy and need to measure small mA current, which increases the difficulty of acquisition and equipment expenditure.
An MPPT system for thermoelectric energy acquisition is designed, by providing a first thermocouple and a second thermocouple at the hot and cold ends of the thermoelectric module, the temperature difference electromotive force is measured, and transmitted to the MPPT control of the WSN terminal node through an amplification circuit. The module, combined with the BOOST circuit and the voltage monitor, controls the voltage across the thermoelectric module through the pulse width modulation signal, so that it tracks to the maximum power point.
This system avoids energy loss in traditional MPPT systems, improves energy utilization, does not need to disconnect the circuit to measure open circuit voltage, reduces the need to measure small current in mA, and reduces equipment expenditure and energy loss.
Smart Images
Figure CN222531554U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of power supply systems, in particular to an MPPT system for thermoelectric energy collection. Background Art
[0002] With the development of sensor technology and communication technology, mankind has entered the information age of the Internet of Everything. By using the Internet of Things, various types of objects and information systems can be connected, thereby realizing functions such as data monitoring, remote control and automation. However, the promotion and use of the Internet of Things is limited by the limited battery capacity and life and the complicated wiring of wired power. In recent years, the development of microelectronic devices has made energy harvesting technology a feasible solution to overcome these limitations. By converting energy in the environment into electrical energy, the self-powered IoT sensor nodes can be realized. In reality, there are a large number of hot walls on site in large industrial enterprises such as power plants, making the research on thermoelectric energy harvesting valuable for real-world applications.
[0003] Since the thermoelectric module (TEG) generates mW / K-level electrical energy, its output power is relatively small, and MPPT (maximum power point tracking) is needed to improve the energy conversion efficiency of TEG to ensure the stability and high efficiency of power supply. Existing thermoelectric energy collection mostly uses the open circuit voltage method and the perturbation observation method. During the use of the open circuit voltage method, the TEG needs to be disconnected from the WSN node. During the disconnection period, the energy generated by the TEG cannot be collected in time, which will undoubtedly cause a waste of TEG energy collection. The perturbation observation method requires measuring the small mA current of the TEG. Measuring small currents will undoubtedly increase the difficulty of collection and increase equipment expenditure and energy loss. Summary of the invention
[0004] The technical problem to be solved by the utility model is to provide an MPPT system for thermoelectric energy collection, which overcomes the shortcomings of the traditional MPPT system, avoids energy loss and improves energy utilization.
[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is: an MPPT system for thermoelectric energy collection, including a thermoelectric module, the hot end and the cold end of the thermoelectric module are respectively provided with a first thermocouple and a second thermocouple, the first thermocouple and the second thermocouple are connected to a thermoelectric differential electromotive force measurement module, the thermoelectric differential electromotive force measurement module transmits the measured thermoelectric differential electromotive force to the MPPT control module of the WSN terminal node through an amplification circuit, the thermoelectric module and the BOOST circuit form a power supply loop, the power supply loop supplies power to the load, the voltage monitor monitors the voltage at both ends of the thermoelectric module and transmits it to the WSN terminal node, and the WSN terminal node sends a pulse width modulation signal to control the voltage at both ends of the thermoelectric module.
[0006] In a preferred solution, the temperature measuring ends of the first thermocouple and the second thermocouple are respectively buried in the center of the first ceramic plate and the second ceramic plate at the hot end and the cold end of the thermoelectric module.
[0007] In a preferred solution, the temperature measuring ends of the first thermocouple and the second thermocouple are welded to copper sheets at both ends of the same semiconductor of the thermoelectric module.
[0008] In a preferred solution, the WSN terminal node sends a pulse width modulation signal to control the voltage across the thermoelectric module to be half of the open circuit voltage.
[0009] The utility model provides an MPPT system for thermoelectric energy collection. The WSN (wireless sensor network) terminal node collects the temperature difference electromotive force through the amplification circuit and calculates the open circuit voltage according to the mathematical fitting formula. At the same time, the WSN also collects the TEG loop voltage in the circuit through the voltage monitor. The WSN sends a pulse width modulation signal to control the loop voltage at both ends of the TEG to be half of the open circuit voltage, so that the TEG can be tracked to the maximum power point. Compared with the system that does not need to disconnect the circuit to measure the TEG open circuit voltage, compared with the perturbation observation method, the system reduces the mA small current of the TEG, overcomes the shortcomings of the traditional MPPT, avoids energy loss, and improves energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The utility model is further described below in conjunction with the accompanying drawings and embodiments:
[0011] Figure 1 It is the principle circuit diagram of the utility model;
[0012] Figure 2 This is a schematic diagram of the contact between the thermocouple temperature measuring end and the TEG;
[0013] Figure 3 It is a schematic diagram of the contact part between the thermocouple temperature measuring end and the TEG in another embodiment;
[0014] Figure 4 It is the simulation model of TEG module;
[0015] Figure 5 This is a diagram illustrating the simulation principle;
[0016] Figure 6 This is a flowchart of the operation flow when using this system;
[0017] In the figure: a first ceramic plate 1, a second ceramic plate 2, a P-type semiconductor 3, an N-type semiconductor 4, a copper sheet 5, a first thermocouple 6, a second thermocouple 7, a thermoelectric module 8, a BOOST circuit 9, a voltage monitor 10, a thermoelectric potential measurement module 11, an amplifying circuit 12, and a WSN terminal node 13. DETAILED DESCRIPTION
[0018] like Figure 1 As shown, an MPPT system for thermoelectric energy collection includes a thermoelectric module (TEG), wherein the hot end and the cold end of the thermoelectric module are respectively provided with a first thermocouple and a second thermocouple, the first thermocouple and the second thermocouple are connected to a thermoelectric differential electromotive force measurement module, the thermoelectric differential electromotive force measurement module transmits the measured thermoelectric differential electromotive force to an MPPT control module of a WSN terminal node through an amplification circuit, the thermoelectric module and the BOOST circuit form a power supply loop, the power supply loop supplies power to the load, the voltage monitor monitors the voltage at both ends of the thermoelectric module and transmits it to the WSN terminal node, the WSN terminal node sends a pulse width modulation signal to control the voltage at both ends of the thermoelectric module, the WSN terminal node sends a pulse width modulation signal to control the voltage at both ends of the thermoelectric module to be half of the open circuit voltage, so that the TEG can track the maximum power point.
[0019] There are two ways to connect the temperature measuring ends of the first thermocouple and the second thermocouple to the TEG:
[0020] like Figure 2 As shown, the temperature measuring ends of the first thermocouple and the second thermocouple are respectively buried at the geometric centers of the first ceramic plate and the second ceramic plate at the hot end and the cold end of the thermoelectric module.
[0021] like Figure 3 As shown, the temperature measuring ends of the first thermocouple and the second thermocouple are welded on the copper sheets at both ends of the same semiconductor of the thermoelectric module.
[0022] In this embodiment, the effectiveness of the system is demonstrated through simulation and experiments:
[0023] Building the TEG model:
[0024] First, use the thermocouples on both sides of the TEG to measure the temperature difference electromotive force and record the TEG open circuit voltage at this moment. According to the corresponding relationship between the two, the mathematical fitting relationship formula between the TEG temperature difference and the open circuit voltage is obtained. The TEG simulation model is as follows: Figure 4 shown.
[0025] Conduct simulations and experiments:
[0026] Build a simulation circuit including TEG simulation model, boost DC-DC boost circuit, thermocouple temperature measurement and its amplification circuit and MPPT algorithm module, as shown below: Figure 5 shown.
[0027] At the same time, we also build the experimental circuit diagram, such as Figure 1As shown, it includes TEG, thermocouple temperature measurement and its amplification circuit, BOOST circuit and WSN node, wherein the WSN node includes a digital input and output port (DIO), which can use a digital-to-analog converter (ADC) to collect the TEG loop voltage in the circuit and send out a pulse width modulation (PWM) signal to control the BOOST circuit.
[0028] Then according to Figure 6 The process steps shown are as follows: the WSN (wireless sensor network) terminal node collects the temperature difference electromotive force after the amplification circuit and calculates the open circuit voltage according to the mathematical fitting formula. At the same time, the WSN also collects the TEG loop voltage in the circuit through the voltage monitor. The WSN sends a pulse width modulation signal to control the loop voltage at both ends of the TEG to be half of the open circuit voltage, so that the TEG can track to the maximum power point.
[0029] Compared with the perturbation observation method, this system does not need to disconnect the circuit to measure the TEG open circuit voltage. Compared with the perturbation observation method, it reduces the mA small current measured for TEG, overcomes the shortcomings of traditional MPPT, avoids energy loss, and improves energy utilization.
Claims
1. An MPPT system for thermoelectric energy harvesting, comprising a thermoelectric module, characterized in that: The hot end and the cold end of the thermoelectric module are respectively provided with a first thermocouple and a second thermocouple, the first thermocouple and the second thermocouple are connected to a thermoelectric differential electromotive force measurement module, the thermoelectric differential electromotive force measurement module transmits the measured thermoelectric differential electromotive force to the MPPT control module of the WSN terminal node through an amplification circuit, the thermoelectric module and the BOOST circuit form a power supply loop, the power supply loop supplies power to the load, the voltage monitor monitors the voltage at both ends of the thermoelectric module and transmits it to the WSN terminal node, and the WSN terminal node sends a pulse width modulation signal to control the voltage at both ends of the thermoelectric module.
2. The MPPT system for thermoelectric energy harvesting according to claim 1, characterized in that: The temperature measuring ends of the first thermocouple and the second thermocouple are respectively buried at the center of the first ceramic plate and the second ceramic plate at the hot end and the cold end of the thermoelectric module.
3. The MPPT system for thermoelectric energy harvesting according to claim 1, characterized in that: The temperature measuring ends of the first thermocouple and the second thermocouple are welded on copper sheets at both ends of the same semiconductor of the thermoelectric module.
4. The MPPT system for thermoelectric energy harvesting according to claim 1, characterized in that: The WSN terminal node sends a pulse width modulation signal to control the voltage across the thermoelectric module to be half of the open circuit voltage.