Thermoelectric management system and method based on mixed zero-current detection and emergency mode
By using a hybrid zero-current detection and emergency mode thermoelectric management system, the switching cycle and conduction time are adjusted in real time. Combined with energy storage capacitors, this solves the problems of limited battery life and unstable TEG output in wireless sensor networks, and improves the system's load capacity and energy harvesting efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGZHOU UNIVERSITY
- Filing Date
- 2026-02-02
- Publication Date
- 2026-05-01
AI Technical Summary
In wireless sensor networks, battery-powered sensor nodes have limited lifespans, and large-capacity batteries increase device size and weight, limiting their deployment; TEG transducers have variable output voltages, requiring energy harvesting interfaces for stable output; and DC-DC converters face challenges in maintaining efficient conversion over a wide input power range.
The thermoelectric management system based on hybrid zero-current detection and emergency mode includes modules for data acquisition, enable signal generation, data analysis, thermal energy storage, and power supply regulation. By detecting input and output voltages in real time, it dynamically adjusts the switching cycle and conduction time, and provides emergency power supply under heavy loads in combination with energy storage capacitors, thus avoiding energy waste.
It improves the system's load-carrying capacity at the same conversion efficiency, reduces output voltage ripple, achieves high-precision zero-current detection, extends equipment life, and reduces maintenance costs.
Smart Images
Figure CN121965846A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of integrated circuit technology, and more particularly to a thermoelectric management system and method based on hybrid zero-current detection and emergency mode. Background Technology
[0002] Wireless sensor networks (WSNs) play a crucial role in IoT applications, enabling data collection and transmission across diverse environments. However, battery-powered sensor nodes present significant challenges due to their limited lifespan, requiring regular maintenance and resulting in substantial replacement costs. Furthermore, utilizing large-capacity batteries to extend lifespan leads to increased size and weight, limiting their deployment in certain situations, such as wearable devices. To overcome these limitations, energy harvesting technology has emerged as a compelling solution for WSNs. It allows the extraction of energy from the environment, including solar, thermal, vibrational, and radio frequency energy, providing a sustainable energy supply for IoT devices. This reduces maintenance costs and extends device lifespan. Multi-source energy harvesting is becoming increasingly attractive due to its enhanced reliability. Among various options, TEG transducers are appealing due to their high power density with a small form factor. However, the output voltage of these transducers is highly dependent on environmental conditions, necessitating an energy harvesting interface to convert this variable voltage into a stable output suitable for the load device.
[0003] Designing energy harvesting circuits presents several challenges. First, WSNs typically operate over a wide power range; for example, medical heart rate monitors primarily operate in low-power standby mode, with power consumption in the μW range. However, during operation, peak power can spike to the mW range, despite a lower overall average power. Second, the output voltage of a battery can differ by 90mV over a 1–2°C temperature difference, demanding that DC-DC converters maintain high conversion efficiency across a wide input power range. Simultaneously, DCM control is frequently employed, with the key being the timing of the high-side switch turn-off at the output. Turning off the inductor too early wastes inductor energy, while turning off too late generates reverse current, resulting in energy loss. Therefore, precise zero-current sensing is crucial for DCM control. Finally, with the increasing number of load devices and load demands, DC-DC converters are evolving from single-output to single-inductor multi-output and wider load-carrying ranges. Summary of the Invention
[0004] To address the aforementioned issues, this invention provides a thermoelectric management system and method based on hybrid zero-flow detection and emergency mode.
[0005] To achieve the above objectives, this application proposes a thermoelectric management system based on hybrid zero-flow detection and emergency mode, including: The data acquisition module is used to sample the open-circuit voltage of the transducer to obtain the maximum power point voltage of the transducer; The enable signal generation module is used to compare the real-time input voltage with the maximum power point voltage to generate an input enable signal, and at the same time, compare the output voltage with the corresponding reference voltage through a hysteresis comparator to generate an output enable signal. The data analysis module is used to process the input enable signal and the output enable signal to obtain the switching cycle and conduction time of the power switch. Thermoelectric energy storage module is used by the gate controller to control the power switch based on the switching cycle and conduction time to store thermoelectric energy in the inductor; The hybrid zero-current detection module is used to transfer energy from the energy storage capacitor to the inductor when the real-time input voltage or real-time output voltage of the transducer fails to reach the rated voltage for several consecutive cycles. The power supply regulator module is used to control the conduction of the power switching transistor according to the energy priority required by the output voltage. When the real-time output voltage is detected to reach the rated voltage, the power switching transistor is turned off to complete the thermoelectric management.
[0006] In some embodiments, the hybrid zero-current detection module includes an analog comparator coarse adjustment section and a digital capacitor array fine adjustment section.
[0007] In some embodiments, the gate controller includes a drive circuit.
[0008] In some embodiments, the data acquisition module includes a sample-and-hold circuit and a sampling clock generator, wherein the sampling clock generator includes a ring oscillator.
[0009] In some embodiments, the enable signal generation module includes a maximum power point tracking circuit and a voltage regulator circuit. The maximum power point tracking circuit and the voltage regulator circuit include a dynamic comparator, which is used to detect the thermal voltage in real time and output a real-time enable signal.
[0010] In some embodiments, the data analysis module includes a single-inductor dual-output controller, which includes digital logic circuitry.
[0011] In some embodiments, the power switch includes an input source power transistor, an energy flow power transistor, and an output power transistor.
[0012] To achieve the above objectives, this application also proposes a thermoelectric management method based on hybrid zero-flow detection and emergency mode, including: The open-circuit voltage of the transducer is sampled to obtain the voltage at the maximum power point of the transducer; The real-time input voltage is compared with the maximum power point voltage to generate an input enable signal. At the same time, the real-time output voltage is compared with the corresponding reference voltage through a hysteresis comparator to generate an output enable signal. The input enable signal and the output enable signal are processed to obtain the switching period and conduction time of the power switch. The gate controller controls the power switch based on the switching cycle and on-time to store thermoelectric energy in the inductor; When the real-time input voltage or real-time output voltage of the transducer fails to reach the rated voltage for several consecutive cycles, the energy of the energy storage capacitor is transferred to the inductor. The power switch is controlled according to the energy priority of the output voltage demand. When the real-time output voltage is detected to reach the rated voltage, the power switch is turned off.
[0013] The beneficial effects of this invention are as follows: 1. By real-time detection of the energy status at the input and output ends, the switching cycle and conduction time are dynamically adjusted to keep the thermoelectric energy at its maximum power point. Compared with traditional energy harvesting systems with fixed clocks, this system has a higher load-carrying capacity at the same conversion efficiency level.
[0014] 2. Utilizing an emergency power supply mode with energy storage capacitors, the system monitors the output voltage cycle by cycle and adaptively allocates energy from the storage capacitors to the load under heavy load conditions. Simultaneously, during each switching cycle, excess energy from the inductor is stored in the storage capacitors via the SGPC power transistors. Compared to traditional energy harvesting systems lacking storage capacitors, this thermoelectric energy harvesting system significantly improves the system's load-carrying capacity. The storage capacitors also reduce the ripple of the dual-output voltage while storing excess energy.
[0015] 3. By using a hybrid zero-current detection module, the drawbacks of high power consumption of fully analog zero-current detectors and low flexibility of fully digital zero-current detectors are avoided, achieving low-power and high-precision detection of inductor zero-current points in DCM mode. Attached Figure Description
[0016] Figure 1 A block diagram of a thermoelectric management system based on hybrid zero-flow detection and emergency mode provided for a specific embodiment of the present invention; Figure 2 A schematic diagram of the control circuit provided for a specific embodiment of the present invention; Figure 3 A schematic diagram of a maximum power point tracking circuit provided for a specific embodiment of the present invention; Figure 4 A single-inductor dual-output controller provided in a specific embodiment of the present invention; Figure 5A circuit diagram of a hybrid zero-current detection module provided in a specific embodiment of the present invention; Figure 6 This is a flowchart of a thermoelectric management method based on hybrid zero-current detection and emergency mode in a specific embodiment of the present invention; Figure 7 The circuit diagram for emergency power supply mode provided in a specific embodiment of the present invention. Detailed Implementation
[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] refer to Figure 1 As shown, this application provides a thermoelectric management system based on hybrid zero-flow detection and emergency mode, including: The data acquisition module is used to sample the open-circuit voltage of the transducer to obtain the maximum power point voltage of the transducer; The enable signal generation module is used to compare the real-time input voltage with the maximum power point voltage to generate an input enable signal, and at the same time, compare the output voltage with the corresponding reference voltage through a hysteresis comparator to generate an output enable signal. The data analysis module processes the input and output enable signals to obtain the switching cycle and conduction time of the power switch. The thermal energy storage module is used by the gate controller to control the power switch based on the switching cycle and conduction time, and store thermoelectric energy in the inductor to complete the management of thermoelectricity.
[0019] The hybrid zero-current detection module is used to transfer energy from the energy storage capacitor to the inductor when the real-time input voltage or real-time output voltage of the transducer fails to reach the rated voltage for several consecutive cycles. The power supply regulator module is used to control the conduction of the power switching transistor according to the energy priority required by the output voltage. When the real-time output voltage is detected to have reached the rated voltage, the power switching transistor is turned off.
[0020] Specifically, the converter in this application is an integrated single-inductor dual-output Buck-Boost converter. The SIDO-BBC has 7 power switches, including VGTEG and VGSTO for input source selection, VGN1 and VGN2 for regulating energy flow, and VGP1, VGP2 and VGPC for output path selection.
[0021] Furthermore, different combinations of power transistors can be used to configure it as a boost converter, a buck converter, and a buck-boost converter. In addition, by dynamically adjusting the switching cycle and conduction time based on real-time monitoring of the energy at the input and output, the converter can ensure that the thermoelectric energy is at its maximum power point, or that unnecessary energy flow to the load is avoided. By automatically switching between different operating modes, it provides more power paths and optimizes energy flow. Compared to traditional energy harvesting systems with fixed clocks, this thermoelectric energy harvesting system has a higher load-carrying capacity at the same conversion efficiency.
[0022] refer to Figures 2-4 As shown, the control circuit in this application integrates a sampling clock generator, a sample-and-hold circuit, a maximum power point tracking (MPPT) circuit, a gate controller, a voltage regulator circuit, a single-inductor dual-output controller, a power supply regulator module, and a hybrid zero-current detection module (H-ZCD). The clock generator, composed of a ring oscillator, provides the sampling clock signal to the sample-and-hold circuit, which in turn provides the open-circuit voltage of the maximum power voltage point for the SIDO-BBC. The voltage regulator circuit compares VOUT1 and VOUT2 with the corresponding reference voltages (1.2V and 1V) using a hysteresis comparator to obtain output enable signals EN1 and EN2. The MPPT circuit generates an input enable signal EN0, which is then input to the single-inductor dual-output controller. The single-inductor dual-output controller outputs the switching cycle and the on-time of the power transistor, and dynamically adjusts the switching cycle and on-time based on EN0, EN1, and EN2.
[0023] The sample-and-hold circuit is set to activate once at fixed intervals. C1 and C2 are both on-chip capacitors. See [link / details]. Figure 3 During the sampling phase, the load switch SET' is open, sampling the open-circuit voltage of the transducer. At the same time, the auxiliary switch SET1 is closed, sampling the open-circuit voltage of the transducer onto capacitor C1, while simultaneously clearing the charge on C2. During the hold phase, the load switch SET' is closed, allowing the converter's input voltage VTEG to quickly reach the open-circuit voltage, significantly reducing energy waste during MPPT when the converter and transducer are disconnected.
[0024] The control circuit operates in multiple states depending on the converter's input and output conditions. During the inductor charging phase, if the TEG is sufficient and the output voltage is controllable, VGTEG and VGN2 are turned on, while the remaining power transistors remain off. Thermoelectric energy is transferred to the inductor until the thermoelectric voltage drops below the maximum power voltage point, at which point VGTEG and VGN2 are turned off. If the TEG is insufficient or the output voltage fails to reach the rated voltage for several consecutive cycles, the emergency power supply mode is activated. VGSTO and VGN2 are turned on, while the remaining power transistors remain off. The energy from the energy storage capacitor is transferred to the inductor in a short-term, high-volume manner. After a certain period, VGSTO and VGN2 are turned off. During the inductor discharge phase, VGN1 is turned on, while VGP1 and VGP2 are turned on individually according to the priority of energy demand from VOUT1 to VOUT2, until the inductor current is zero or VOUT1 and VOUT2 reach their rated voltages, at which point VGP1 and VGP2 are turned off. If the inductor still has residual energy when VOUT1 and VOUT2 reach their rated voltages, VGPC is turned on, and energy is transferred to the energy storage capacitor, until the inductor current is zero, at which point VGN1 and VGPC are turned off. By real-time monitoring of the energy status at the input and output terminals, the system dynamically adjusts the switching cycle and conduction time to keep the thermoelectric energy at its maximum power point. Compared to traditional energy harvesting systems with fixed clocks, this system has a higher load-carrying capacity at the same conversion efficiency level. Simultaneously, the use of the energy storage capacitor greatly improves the system's load-carrying capacity, and while storing excess energy, the ripple of the dual-output voltage is reduced.
[0025] The MPPT controller consists of a dynamic comparator that monitors thermal voltage in real time and outputs a real-time enable signal to ensure that the converter always operates near its maximum power point.
[0026] The sample-and-hold circuit uses the open-circuit voltage method to find the maximum power point and adjusts the input voltage to fluctuate around the maximum power point.
[0027] The single-inductor dual-output controller is composed of digital logic circuits, which enable energy to be transferred to each output according to the priority of VOUT1, VOUT2, and energy storage capacitor.
[0028] refer to Figure 5As shown, the hybrid zero-current detection module H-ZCD specifically includes an analog comparator coarse adjustment section and a digital capacitor array fine adjustment section, accurately detecting the zero-current point in DCM mode. The H-ZCD's analog coarse adjustment section uses a zero-crossing comparator to compare the inductor's VL point with the 0 voltage, outputting the comparison result early to ensure it's output before the zero-current point, avoiding the high power consumption caused by comparator offset. The comparator result is input to the digital circuit, which consists of a counter and a 6-bit capacitor array. The digital circuit generates the turn-on time according to a rated step size, checking cycle by cycle whether the power transistor's turn-off point is earlier than the zero-current point. The counter controls the number of working capacitors in the capacitor array, dynamically adjusting the turn-on time. Finally, the power transistor's turn-off point is positioned before or after the zero-current point, with an error within 500uA. Compared to traditional all-analog and all-digital zero-current detectors, this hybrid zero-current detection module combines the advantages of wide current range modulation of all-analog zero-current detectors and low power consumption of all-digital zero-current detectors, avoiding the disadvantages of high power consumption of all-analog zero-current detectors and low flexibility of all-digital zero-current detectors, and achieving low-power and high-precision detection of inductor zero-current points in DCM mode.
[0029] Specifically, the gate controller consists of a drive circuit that enables the power transistor to switch at a reasonable speed, thereby reducing energy loss.
[0030] refer to Figure 6 As shown, to achieve the above objectives, another aspect of this application proposes a thermoelectric management method based on hybrid zero-current detection and emergency mode, including: S101: Sample the open-circuit voltage of the transducer to obtain the maximum power point voltage of the transducer; S102: Compare the real-time input voltage with the maximum power point voltage to generate an input enable signal, and at the same time compare the real-time output voltage with the corresponding reference voltage through a hysteresis comparator to generate an output enable signal. S103: Process the input enable signal and the output enable signal to obtain the switching period and conduction time of the power switch. S104: Based on the switching cycle and conduction time, thermoelectric energy is stored in the inductor and energy storage capacitor; S105: When the real-time input voltage or real-time output voltage of the transducer fails to reach the rated voltage for several consecutive cycles, the energy of the energy storage capacitor is transferred to the inductor. S106: Control the conduction status of the power switch according to the energy priority of the output voltage demand. When the real-time output voltage is detected to reach the rated voltage, the power switch is turned off to complete the thermoelectric management.
[0031] refer to Figure 7As shown, further, when the real-time input voltage or real-time output voltage of the transducer fails to reach the rated voltage for several consecutive cycles, the Emergency Power Supply Mode (EPSM) is activated. This involves monitoring the output voltage cycle by cycle and adaptively allocating energy from the storage capacitor. When VOUT1 and VOUT2 are below their rated reference voltage at the inductor zero-current point for several consecutive cycles, the system determines that it is under heavy load, and thermoelectric energy alone is insufficient to support the current load. The system immediately activates EPSM to allocate energy from the storage capacitor to the load in the next switching cycle. The on-time is determined by the rated on-time timer. Due to the large amount of energy in the storage capacitor, a short extraction time can provide a significant amount of energy to the load. Simultaneously, due to the presence of the storage capacitor, when the inductor releases energy to bring VOUT1 and VOUT2 to their rated voltages in each switching cycle, there is still excess energy. This energy will be stored in the storage capacitor through the SGPC power transistor. Compared to traditional energy harvesting systems that lack energy storage capacitors, this thermoelectric energy harvesting system can greatly improve the system's load-carrying capacity. While storing excess energy, the energy storage capacitors also reduce the ripple of the dual-output voltage.
[0032] Based on the above, the workflow of this invention is as follows: The open-circuit voltage of the transducer is sampled to obtain the maximum power point voltage (MPPT). The MPPT circuit compares the real-time input voltage with the MPPT to generate the input enable signal EN0. The voltage regulator circuit compares VOUT1 and VOUT2 with the corresponding reference voltages (1.2V and 1V) through a hysteresis comparator to obtain the output enable signals EN1 and EN2. The single-inductor dual-output controller processes EN0, EN1, and EN2 to obtain the real-time switching cycle and conduction time, storing thermoelectric energy in the inductor. If the TEG is insufficient or the output voltage fails to reach the rated voltage for several consecutive cycles, the emergency power supply mode is activated, mobilizing the energy stored in the capacitor to transfer energy to the inductor.
[0033] On the load side, the inductors are turned on individually according to the priority of energy demand from VOUT1 to VOUT2. If VOUT1 and VOUT2 reach their rated voltages and the inductors still have residual energy, VGPC is turned on, and the energy is transferred to the energy storage capacitor until the hybrid zero-current detection module outputs a high-side power transistor turn-off signal to prevent energy waste and reverse current flow, thus completing the energy acquisition and transmission of the transducer.
[0034] The thermoelectric management system of this application dynamically adjusts the switching cycle and conduction time by real-time detection of the energy status at the input and output ends, so that the thermoelectric energy is at the maximum power point. Compared with the traditional energy harvesting system with a fixed clock, this system has a higher load-carrying capacity at the same conversion efficiency level.
[0035] This emergency power supply mode, utilizing energy storage capacitors, monitors the output voltage cycle by cycle and adaptively allocates energy from the capacitors to the load under heavy loads. Simultaneously, during each switching cycle, excess energy from the inductor is stored in the energy storage capacitors via the SGPC power transistors. Compared to traditional energy harvesting systems lacking energy storage capacitors, this thermoelectric energy harvesting system significantly improves the system's load-carrying capacity. The energy storage capacitors also reduce the ripple of the dual-output voltage while storing excess energy. The hybrid zero-current detection module combines the wide current range modulation of a fully analog zero-current detector with the low power consumption of a fully digital zero-current detector, avoiding the high power consumption of a fully analog zero-current detector and the low flexibility of a fully digital zero-current detector. This enables low-power, high-precision detection of the inductor zero-current point in DCM mode. This application dynamically adjusts the switching cycle and conduction time by real-time detection of the energy status at the input and output ends, so that the thermoelectric energy is at its maximum power point. Compared with traditional energy harvesting systems with fixed clocks, this system has a higher load-carrying capacity at the same conversion efficiency level.
[0036] This emergency power supply mode, utilizing energy storage capacitors, monitors the output voltage cycle by cycle and adaptively allocates energy from the capacitors to the load under heavy loads. Simultaneously, excess energy from the inductor is stored in the capacitors via the SGPC power transistor during each switching cycle. Compared to traditional energy harvesting systems lacking storage capacitors, this thermoelectric energy harvesting system significantly improves the system's load-carrying capacity. The storage capacitors store excess energy while reducing ripple in the dual-output voltage. Through a hybrid zero-current detection module, it avoids the high power consumption of fully analog zero-current detectors and the low flexibility of fully digital zero-current detectors, achieving low-power, high-precision detection of the inductor's zero-current point in DCM mode.
[0037] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A thermoelectric management system based on hybrid zero-current detection and emergency mode, characterized in that, include: The data acquisition module is used to sample the open-circuit voltage of the transducer to obtain the maximum power point voltage of the transducer; The enable signal generation module is used to compare the real-time input voltage with the maximum power point voltage to generate an input enable signal, and at the same time, compare the output voltage with the corresponding reference voltage through a hysteresis comparator to generate an output enable signal. The data analysis module processes the input and output enable signals to obtain the switching cycle and conduction time of the power switch. Thermoelectric energy storage module is used by the gate controller to control the power switch based on the switching cycle and conduction time to store thermoelectric energy in the inductor; The hybrid zero-current detection module is used to transfer energy from the energy storage capacitor to the inductor when the real-time input voltage or real-time output voltage of the transducer fails to reach the rated voltage for several consecutive cycles. The power supply regulator module is used to control the conduction of the power switching transistor according to the energy priority required by the output voltage. When the real-time output voltage is detected to reach the rated voltage, the power switching transistor is turned off to complete the thermoelectric management.
2. The thermoelectric management system based on hybrid zero-flow detection and emergency mode according to claim 1, characterized in that, The hybrid zero-current detection module includes an analog comparator coarse adjustment section and a digital capacitor array fine adjustment section.
3. The thermoelectric management system based on hybrid zero-flow detection and emergency mode according to claim 1, characterized in that, The gate controller includes a drive circuit.
4. The thermoelectric management system based on hybrid zero-flow detection and emergency mode according to claim 1, characterized in that, The data acquisition module includes a sample-and-hold circuit and a sampling clock generator, wherein the sampling clock generator includes a ring oscillator.
5. The thermoelectric management system based on hybrid zero-flow detection and emergency mode according to claim 1, characterized in that, The enable signal generation module includes a maximum power point tracking circuit and a voltage regulator circuit. The maximum power point tracking circuit and the voltage regulator circuit include a dynamic comparator. The dynamic comparator is used to detect the thermal voltage in real time and output a real-time enable signal.
6. The thermoelectric management system based on hybrid zero-flow detection and emergency mode according to claim 1, characterized in that, The data analysis module includes a single-inductor dual-output controller, which includes digital logic circuitry.
7. The thermoelectric management system based on hybrid zero-flow detection and emergency mode according to claim 1, characterized in that, The power switch includes an input source power transistor, an energy flow power transistor, and an output power transistor.
8. A thermoelectric management method based on hybrid zero-current detection and emergency mode, characterized in that, include: The open-circuit voltage of the transducer is sampled to obtain the voltage at the maximum power point of the transducer; The real-time input voltage is compared with the maximum power point voltage to generate an input enable signal. At the same time, the real-time output voltage is compared with the corresponding reference voltage through a hysteresis comparator to generate an output enable signal. The input enable signal and the output enable signal are processed to obtain the switching period and conduction time of the power switch. The gate controller controls the power switch based on the switching cycle and on-time to store thermoelectric energy in the inductor; When the real-time input voltage or real-time output voltage of the transducer fails to reach the rated voltage for several consecutive cycles, the energy of the energy storage capacitor is transferred to the inductor. The power switch is controlled according to the energy priority of the output voltage demand. When the real-time output voltage reaches the rated voltage, the power switch is turned off to complete the thermoelectric management.