Direct current solid state circuit breaker self-powered device and method based on thermoelectric generation

Abstract

A self-powered DC solid-state circuit breaker device and method based on thermoelectric power generation are disclosed. In the device, the power semiconductor device adopts a double-sided heat dissipation packaging structure, with a first heat dissipation surface and a second heat dissipation surface arranged opposite each other. The thermoelectric power generation unit is disposed between the first heat dissipation surface and the cooling medium, converting the temperature difference formed by the heat loss generated by the power semiconductor device during conduction or switching into electrical energy. An energy harvesting unit is electrically connected to the thermoelectric power generation unit to perform voltage boosting and stabilization processing on the electrical energy. An energy storage unit is electrically connected to the energy harvesting unit to store the processed electrical energy. A power supply control unit is electrically connected to the energy storage unit, and the power supply control unit supplies power to the DC solid-state circuit breaker without external auxiliary power supply. The second heat dissipation surface is connected to the main heat dissipation structure, and the heat dissipation capacity of the main heat dissipation structure is greater than that of the first heat dissipation surface, so as to guide the heat to be dissipated preferentially through the second heat dissipation surface and maintain the temperature difference between the first heat dissipation surface and the cooling medium.

Description

Technical Field

[0001] This invention relates to the field of DC power transmission and distribution technology, and in particular to a self-powered device and method for DC solid-state circuit breakers based on thermoelectric power generation. Background Technology

[0002] With the rapid development of DC power distribution systems, DC microgrids, and new energy grid-connected systems, DC solid-state circuit breakers (SSDs) have gradually become important protection devices in DC systems due to their advantages such as fast breaking speed, no electric arc, and ease of intelligent control. DC SSDs typically use power semiconductor devices as the core breaking element and rely on auxiliary functional modules such as current and voltage detection, drive control, and fault recording to work together to achieve rapid protection of the DC system. In existing technologies, DC SSDs usually require an independent auxiliary power supply to achieve the functions of these key modules. This auxiliary power supply is generally obtained through DC bus power, external low-voltage power supply, or independent battery configuration. However, in high-voltage DC systems or applications with high requirements for electrical isolation and safety levels, introducing an additional auxiliary power supply not only increases the complexity of the system structure but may also lead to problems such as difficulties in insulation design, reduced reliability, and increased maintenance costs.

[0003] To reduce reliance on external auxiliary power sources, various self-powering or self-sufficient power solutions have been proposed in existing technologies. For example, a common approach is to draw power directly from the DC bus or power devices, supplying power to the control and drive modules via resistive voltage division, transformers, or power electronic conversion circuits. This type of solution still essentially relies on the presence of electrical energy in the DC system; when the DC bus voltage drops abnormally or a serious system fault occurs, the self-powering capability may be lost, affecting the reliable operation of the circuit breaker. Another approach uses energy storage elements or independent batteries as auxiliary energy sources, charging during normal operation to maintain the control and drive functions of the circuit breaker when the main power supply fails. However, this type of solution typically faces problems such as limited capacity and lifespan of energy storage elements, as well as the need for regular maintenance or replacement, especially in high-temperature, high-power-density DC equipment, where long-term reliability is difficult to guarantee. Some solutions also attempt to utilize electromagnetic induction or parasitic energy recovery methods for self-powering, such as obtaining energy by detecting changes in main circuit current, magnetic field changes, or the on-state voltage drop of power devices. However, such solutions generally rely on the main circuit current or voltage conditions. When the system is under light load, standby, or abnormal operating conditions, the energy that can be obtained is limited, making it difficult to stably support the operation of the circuit breaker's key functional modules.

[0004] Furthermore, during operation, DC solid-state circuit breakers inevitably generate conduction and switching losses in their power semiconductor devices, which are then dissipated to the external environment through methods such as air cooling or liquid cooling. In existing technologies, this heat loss is usually considered merely an adverse factor that needs to be eliminated, and its energy value has not been effectively utilized. Meanwhile, in some application scenarios, cooling conditions are relatively easy to obtain, but the introduction of additional auxiliary power supply is limited by high-voltage isolation, safety regulations, or structural conditions. Thermoelectric power generation technology utilizes the Seebeck effect of materials, forming a circuit with P-type and N-type materials. When a temperature difference exists between the two junctions, an electric potential and current are generated in the circuit. Combined with a subsequent energy harvesting module, this converts heat energy into electrical energy. It features all-solid-state operation, maintenance-free operation, small size, and no vibration or noise, and is widely used in passive sensing, waste heat recovery, and other fields. Therefore, thermoelectric power generation technology can be used to convert the heat generated by power semiconductor devices into electrical energy to power key modules in DC solid-state circuit breakers. However, the selection of existing thermoelectric materials typically uses the thermoelectric figure of merit (zT) as the main evaluation index, focusing on the thermoelectric conversion efficiency under steady-state conditions. However, in DC solid-state circuit breaker applications, the temperature difference is determined by both device losses and cooling conditions. The energy extraction process is characterized by limited temperature difference, low output voltage, and power requirements primarily focused on supporting control and drive. Using only zT as the material selection criterion makes it difficult to balance the ability to establish a temperature difference with the actual usable output capacity. Existing self-powered or self-supplied energy solutions still have the following shortcomings: first, they generally rely on the electrical state of the DC bus, resulting in limited resistance to power loss; second, there are issues with the insulation and reliability of the power extraction scheme; and third, they fail to fully utilize the heat resources objectively present during the operation of power semiconductor devices, making it difficult to build a stable and reliable energy supply mechanism without external auxiliary power. Using thermoelectric power supply technology eliminates the need to draw power from the DC bus, thus avoiding electrical insulation or isolation issues. It is suitable for applications with forced air cooling or liquid cooling but unsuitable for introducing independent power supplies or auxiliary power, offering a natural advantage over other methods.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] To address the shortcomings or defects of the existing technology, a self-powered device and method for DC solid-state circuit breakers based on thermoelectric power generation is provided. This method utilizes the on-state heat loss generated during the conduction process of power semiconductor devices to obtain electrical energy, thereby powering key modules in the DC solid-state circuit breaker. The self-powered device uses a power semiconductor device with a double-sided heat dissipation package structure as its core. Energy harvesting structures and main heat dissipation structures are arranged on opposite sides of the device, thus achieving functional separation between thermoelectric energy conversion and the main heat dissipation of the device.

[0007] The objective of this invention is achieved through the following technical solutions.

[0008] A self-powered DC solid-state circuit breaker device based on thermoelectric power generation includes:

[0009] A power semiconductor device employing a double-sided heat dissipation package structure, having a first heat dissipation surface and a second heat dissipation surface arranged opposite to each other;

[0010] Thermoelectric power generation unit is disposed between the first heat dissipation surface and the cooling medium. It forms a low thermal resistance connection path through an insulating thermally conductive interface material to convert the temperature difference formed by the heat loss generated by the power semiconductor device during the conduction or switching process into electrical energy.

[0011] An energy harvesting unit is electrically connected to the thermoelectric generator unit to boost and stabilize the electrical energy.

[0012] An energy storage unit, which is electrically connected to the energy harvesting unit, is used to store processed electrical energy;

[0013] The power supply control unit is electrically connected to the energy storage unit and supplies power to the DC solid-state circuit breaker in the absence of external auxiliary power.

[0014] The second heat dissipation surface is connected to the main heat dissipation structure, and the heat dissipation capacity of the main heat dissipation structure is greater than that of the first heat dissipation surface, so as to guide the heat to be dissipated preferentially through the second heat dissipation surface and maintain a temperature difference between the first heat dissipation surface and the cooling medium; the self-powered device has no electrical connection with the DC bus and DC grid during the entire process of energy extraction and power supply.

[0015] In the aforementioned DC solid-state circuit breaker self-powered device based on thermoelectric power generation, the thermoelectric power generation unit is composed of multiple thermoelectric power generation devices connected in series, parallel or mixed, and each thermoelectric power generation device includes multiple pairs of P-type and N-type thermocouples.

[0016] In the aforementioned DC solid-state circuit breaker self-powered device based on thermoelectric power generation, the main heat dissipation structure is an air-cooled radiator or a liquid-cooled plate; the cooling medium is air, water, or insulating coolant.

[0017] In the aforementioned DC solid-state circuit breaker self-powered device based on thermoelectric power generation, the energy storage unit includes a supercapacitor or a rechargeable battery, configured to store energy during normal operation of the power semiconductor device and release transient high-power electrical energy during initial start-up, fault disconnection, or abnormal operating conditions of the circuit breaker.

[0018] In the aforementioned self-powered DC solid-state circuit breaker based on thermoelectric power generation, the power supply control unit supplies power to the functional modules of the DC solid-state circuit breaker without external auxiliary power. The functional modules include at least one of a current and voltage sensing module, a drive module, a control module, and a fault recording module.

[0019] In the aforementioned DC solid-state circuit breaker self-powered device based on thermoelectric power generation, the power semiconductor device is a SiC MOSFET module, an IGBT module, or a combination thereof.

[0020] The self-powering methods for DC solid-state circuit breaker self-powering devices based on thermoelectric power generation include:

[0021] Step S1: Thermoelectric material selection. If high power density is the priority, select a thermoelectric material system with a higher Seebeck coefficient² × electrical conductivity / thermal conductivity² value; if high output voltage is the priority, select a thermoelectric material system with a higher |Seebeck coefficient| / thermal conductivity value.

[0022] Step S2: The height of the thermocouple is set according to the cooling conditions: 0.5mm-1.5mm for water cooling, 1mm-3mm for air cooling, and 1.5mm-6mm for natural cooling, in order to optimize the output power density.

[0023] Step S3: Calculate the number of thermoelectric generators. Based on the total full-load power consumption of the functional modules, the heat loss of power semiconductor devices, cooling conditions, and the conversion efficiency of the thermoelectric generator unit, determine the minimum number of devices required to meet the continuous power supply demand.

[0024] Step S4: Calculate the establishment time required for the thermal surface of the thermoelectric power generation unit to reach thermal steady state from the ambient temperature after the circuit breaker is opened, and calculate the total electrical energy consumed by the functional modules during this time. Determine the energy storage capacity of the energy storage unit with a margin of not less than 2 times. The self-powered device has no electrical connection with the DC bus and DC grid during the entire process of energy extraction and supply. The second heat dissipation surface is connected to the main heat dissipation structure, guiding the heat to be dissipated preferentially through the second heat dissipation surface, and maintaining a temperature difference between the first heat dissipation surface and the cooling medium, thus constructing a self-powered system decoupled from the electrical state of the DC system.

[0025] In the method described, the thermoelectric material system is a bismuth telluride-based or silver telluride-based material.

[0026] In the method described, in step S4, the thermal steady state is a stable operating state in which the temperature fluctuation of the thermal surface of the thermoelectric generator unit is less than ±2℃.

[0027] In the method described, the settling time t1 required for the thermal surface of the thermoelectric power generation unit to reach thermal steady state from ambient temperature is determined based on the power consumption P of the functional module. load Calculate the total electrical energy E consumed during this time using the following formula. req :

[0028] .

[0029] Compared with existing technologies, the beneficial effects of this invention are as follows: by utilizing the unavoidable heat loss of power semiconductor devices as an energy source, the system's dependence on external power supply conditions is reduced, and the structural complexity and potential failure risks brought by auxiliary power supplies are decreased. This self-powered device is particularly suitable for application scenarios with forced air cooling or liquid cooling conditions, but where it is inconvenient to introduce independent power supply lines or auxiliary power supplies. It has the advantages of compact structure, high energy utilization efficiency, strong safety and environmental adaptability.

[0030] The description provided is merely an overview of the technical solution of this invention. In order to make the technical means of this invention clearer and more understandable, so that those skilled in the art can implement it according to the contents of the specification, and to make the described and other objects, features and advantages of this invention more obvious and understandable, specific embodiments of this invention are described below. Attached Figure Description

[0031] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0032] In the attached diagram:

[0033] Figure 1 This is a schematic diagram of the self-powered DC solid-state circuit breaker based on thermoelectric power generation according to the present invention.

[0034] Figure 2 This is a functional flowchart of the self-powered DC solid-state circuit breaker based on thermoelectric power generation according to the present invention.

[0035] Figure 3 This is a flowchart of the self-powered design method for DC solid-state circuit breakers based on thermoelectric power generation according to the present invention.

[0036] Figure 4 This is a curve showing the relationship between the height of the preferred thermocouple pair and the maximum output power density according to the present invention.

[0037] Figure 5 This is a power example diagram of the signal side of the key functional module of the preferred self-powered device of the present invention;

[0038] Figure 6This is a power example diagram of the power supply side of the key functional module of the preferred self-powered device of the present invention;

[0039] Figure 7 This is a curve showing the relationship between the operating temperature difference and the maximum output power density of the preferred thermoelectric generator unit of the present invention.

[0040] Figure 8 This is a temperature distribution cloud map of the preferred DC solid-state circuit breaker self-powered device under steady state according to the present invention;

[0041] Figure 9 The diagram shows the temperature / output power variation curves during the cold start phase of the preferred DC solid-state circuit breaker self-powered device of the present invention.

[0042] The present invention will be further explained below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0043] Specific embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0044] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0045] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments, and the accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0046] To better understand, such as Figures 1 to 9 As shown, a self-powered DC solid-state circuit breaker based on thermoelectric power generation includes:

[0047] A power semiconductor device employing a double-sided heat dissipation package structure, having a first heat dissipation surface and a second heat dissipation surface arranged opposite to each other;

[0048] Thermoelectric power generation unit is disposed between the first heat dissipation surface and the cooling medium. It forms a low thermal resistance connection path through an insulating thermally conductive interface material to convert the temperature difference formed by the heat loss generated by the power semiconductor device during the conduction or switching process into electrical energy.

[0049] An energy harvesting unit is electrically connected to the thermoelectric generator unit to boost and stabilize the electrical energy.

[0050] An energy storage unit, which is electrically connected to the energy harvesting unit, is used to store processed electrical energy;

[0051] The power supply control unit is electrically connected to the energy storage unit and supplies power to the DC solid-state circuit breaker in the absence of external auxiliary power.

[0052] The second heat dissipation surface is connected to the main heat dissipation structure, and the heat dissipation capacity of the main heat dissipation structure is greater than that of the first heat dissipation surface, so as to guide the heat to be dissipated preferentially through the second heat dissipation surface and maintain a temperature difference between the first heat dissipation surface and the cooling medium; the self-powered device has no electrical connection with the DC bus and DC grid during the entire process of energy extraction and power supply.

[0053] In a preferred embodiment of the self-powered DC solid-state circuit breaker based on thermoelectric power generation, the thermoelectric power generation unit is composed of multiple thermoelectric power generation devices connected in series, parallel or mixed, and each thermoelectric power generation device includes multiple pairs of P-type and N-type thermocouples.

[0054] In a preferred embodiment of the DC solid-state circuit breaker self-powered device based on thermoelectric power generation, the main heat dissipation structure is an air-cooled radiator or a liquid-cooled plate; the cooling medium is air, water or insulating coolant.

[0055] In a preferred embodiment of the DC solid-state circuit breaker self-powered device based on thermoelectric power generation, the energy storage unit includes a supercapacitor or a rechargeable battery, configured to store energy during normal operation of the power semiconductor device and release transient high-power electrical energy during initial start-up, fault disconnection, or abnormal operating conditions of the circuit breaker.

[0056] In a preferred embodiment of the self-powered DC solid-state circuit breaker based on thermoelectric power generation, the power supply control unit supplies power to the functional modules of the DC solid-state circuit breaker without external auxiliary power. The functional modules include at least one of a current and voltage sensing module, a drive module, a control module, and a fault recording module.

[0057] In a preferred embodiment of the self-powered DC solid-state circuit breaker based on thermoelectric power generation, the power semiconductor device is a SiC MOSFET module, an IGBT module, or a combination thereof.

[0058] The self-powering methods for DC solid-state circuit breaker self-powering devices based on thermoelectric power generation include:

[0059] Step S1: Thermoelectric material selection. If high power density is the priority, select a thermoelectric material system with a higher Seebeck coefficient² × electrical conductivity / thermal conductivity² value; if high output voltage is the priority, select a thermoelectric material system with a higher |Seebeck coefficient| / thermal conductivity value.

[0060] Step S2: The height of the thermocouple is set according to the cooling conditions: 0.5mm-1.5mm for water cooling, 1mm-3mm for air cooling, and 1.5mm-6mm for natural cooling, in order to optimize the output power density.

[0061] Step S3: Calculate the number of thermoelectric generators. Based on the total full-load power consumption of the functional modules, the heat loss of power semiconductor devices, cooling conditions, and the conversion efficiency of the thermoelectric generator unit, determine the minimum number of devices required to meet the continuous power supply demand.

[0062] Step S4: Calculate the establishment time required for the thermal surface of the thermoelectric power generation unit to reach thermal steady state from the ambient temperature after the circuit breaker is opened, and calculate the total electrical energy consumed by the functional modules during this time. Determine the energy storage capacity of the energy storage unit with a margin of not less than 2 times. The self-powered device has no electrical connection with the DC bus and DC grid during the entire process of energy extraction and supply. The second heat dissipation surface is connected to the main heat dissipation structure, guiding the heat to be dissipated preferentially through the second heat dissipation surface, and maintaining a temperature difference between the first heat dissipation surface and the cooling medium, thus constructing a self-powered system decoupled from the electrical state of the DC system.

[0063] In a preferred embodiment of the method, the thermoelectric material system is a bismuth telluride-based or silver telluride-based material.

[0064] In a preferred embodiment of the method, in step S4, the thermal steady state is a stable operating state in which the temperature fluctuation of the thermal surface of the thermoelectric generator unit is less than ±2℃.

[0065] In a preferred embodiment of the method, the establishment time t1 required for the thermal surface of the thermoelectric power generation unit to reach thermal steady state from ambient temperature is determined based on the power consumption P of the functional module. load Calculate the total electrical energy E consumed during this time using the following formula. req :

[0066] .

[0067] In one embodiment, power is supplied to a key module in a DC solid-state circuit breaker by utilizing the on-state heat loss generated during the conduction of a power semiconductor device. The core breaking unit of the DC solid-state circuit breaker employs a power semiconductor module in a double-sided heat-dissipating package. This power semiconductor module can be a SiC MOSFET module, an IGBT module, or other power semiconductor device modules that generate significant heat loss during conduction or switching. The power semiconductor module has a first cooling surface and a second cooling surface arranged opposite to each other, with the first side configured as the thermoelectric energy harvesting side and the second side configured as the main heat dissipation side. During normal conduction or switching, the conduction and switching losses of the power semiconductor module are converted into heat within the chip and conducted to the cooling surfaces on both sides through the module package. The self-powered device arranges energy harvesting and heat dissipation structures on the opposite sides of the power semiconductor device, achieving functional separation of thermoelectric energy conversion and device heat dissipation in its structure.

[0068] A self-powered DC solid-state circuit breaker device based on thermoelectric power generation includes:

[0069] Power semiconductor devices are the main working components of solid-state circuit breakers;

[0070] Thermoelectric power generation unit is used to convert the temperature difference formed by the heat loss generated by the power semiconductor device during the conduction or switching process into electrical energy;

[0071] An energy harvesting unit, electrically connected to the thermoelectric generator unit, is used to boost and stabilize the electrical energy output by the thermoelectric generator unit.

[0072] An energy storage unit, electrically connected to the energy harvesting unit, is used to store the processed electrical energy;

[0073] The power supply control unit is electrically connected to the energy storage unit and is used to supply power to the key functional modules of the DC solid-state circuit breaker in the absence of external auxiliary power.

[0074] Figure 1This is a schematic diagram of the preferred structure of the self-powered DC solid-state circuit breaker based on thermoelectric power generation according to the present invention. The power semiconductor device has a first side and a second side heat dissipation surface arranged opposite each other, wherein the first side is used for thermoelectric energy extraction and the second side is used for heat dissipation. The thermoelectric power generation unit forms a thermal connection with the power semiconductor module through an insulating thermally conductive interface material, thereby forming a continuous heat transfer energy extraction path from the power semiconductor device to the cooling medium. The insulating thermally conductive interface material ensures good thermal conductivity and meets the requirements of the power semiconductor module for electrical isolation and withstand voltage level. The thermoelectric power generation unit is composed of multiple thermoelectric power generation devices, each of which is internally formed by multiple pairs of P-type and N-type thermocouples electrically connected. When there is a temperature difference between its hot and cold ends, a thermoelectric potential is generated at both ends of the device under the Seebeck effect. For a single thermocouple pair, its output voltage can be expressed as:

[0075]

[0076] in, S Δ is the Seebeck coefficient of the thermoelectric material. T This refers to the temperature difference between the hot and cold ends. By connecting multiple thermocouple pairs in series or in combination, an output voltage that meets the requirements of the subsequent energy harvesting circuit can be obtained under limited temperature difference conditions.

[0077] The cooling medium includes air or liquid. The second cooling surface of the power semiconductor device is thermally connected to an air-cooled heat sink or a liquid-cooled plate. In liquid-cooling mode, the cooling medium can be water or other insulating coolant. The cooling plate has a flow channel structure inside to improve convective heat transfer. In air-cooling mode, the second cooling surface is connected to a finned heat sink through a heat dissipation substrate and dissipates heat to the environment under forced air cooling. By rationally designing the thermal resistance of the second cooling structure, its heat dissipation capacity is significantly greater than that of the thermoelectric energy harvesting path on the first side. This ensures the junction temperature safety of the power semiconductor device while guiding internal heat to preferentially conduct along the second side, while simultaneously creating a stable and controllable temperature difference on the first side, which is beneficial for the continuous operation of the thermoelectric power generation unit.

[0078] The electrical energy output from the thermoelectric generator is processed by an energy harvesting unit. This energy harvesting unit may include a low-voltage start-up DC-DC boost circuit, a rectification and voltage regulation circuit, used to convert the low-voltage, unstable DC power output from the thermoelectric generator into a stable voltage that meets the needs of energy storage and supply. The processed electrical energy is stored in an energy storage unit, which may be a supercapacitor or a rechargeable battery, with its capacity configured according to the energy demand during circuit breaker startup and under abnormal operating conditions.

[0079] The power supply control unit is electrically connected to the energy storage unit and is used to manage the power supply to the circuit breaker's internal state current and voltage sensing modules, drive modules, control modules, and fault recording modules in the absence of external auxiliary power. The power supply control unit can coordinate the power supply to different functional modules according to the energy storage status, prioritizing the normal operation of modules related to critical circuit breaker actions. Throughout the entire energy extraction and supply process, the self-powered device maintains electrical isolation from the DC bus or DC grid, and does not directly draw power from the DC system, thereby avoiding the impact of high-voltage isolation, bus power failure, and other factors on the circuit breaker's reliability.

[0080] A self-powered design method for DC solid-state circuit breakers based on thermoelectric power generation is described in the following flowchart: Figure 3 As shown, the design steps include the following:

[0081] Step 1: In this embodiment, the selection of thermocouple materials not only considers traditional steady-state thermoelectric material evaluation indicators, but also takes into account the characteristics of DC solid-state circuit breaker energy harvesting scenarios, comprehensively focusing on the output voltage build-up capability and power density requirements under limited temperature difference conditions. Higher power density results in a smaller footprint for the required thermoelectric power generation unit, and higher output voltage leads to higher efficiency for the subsequent energy harvesting unit. The thermocouple material selection is based on the Seebeck coefficient. 2 × Electrical conductivity / Thermal conductivity 2 "Higher thermoelectric material systems are used to obtain higher power density. Thermoelectric material systems with higher Seebeck coefficient / thermal conductivity are selected to obtain higher output voltage. Preferably, silver telluride-based or bismuth telluride-based materials are used."

[0082] Step 2: Determine the appropriate height of the thermocouple pair based on the cooling conditions of the circuit breaker, so that the thermoelectric power generation unit can obtain a higher output power density under the corresponding conditions. The thermocouple pair height ranges are as follows: water cooling conditions 0.5mm-1.5mm (inclusive); air cooling conditions 1mm-3mm (inclusive); natural cooling conditions 1.5mm-6mm (inclusive). Figure 4 The preferred thermocouple pair height and maximum output power density curve of the present invention is a curve showing the relationship between different thermocouple pair heights and the maximum output power density that can be achieved under a fixed operating temperature difference of the thermoelectric power generation unit. In this preferred embodiment, the thermocouple pair height is 0.8 mm.

[0083] Step 3: Calculate the minimum number of thermoelectric generators required based on the total full-load power consumption of the key functional modules. Figure 5This diagram illustrates the power consumption of the signal side of a key functional module in the preferred self-powered device of this invention. This circuit board is the core of the entire device's control and interaction, implementing functions such as data acquisition, processing, storage, communication, and status indication. Through unified scheduling by the main control chip, each module works collaboratively to ensure stable and reliable operation of the device and efficient data interaction with external systems. The power consumption and functions of its main components are as follows: Main control chip (0.4W): As the core control unit, it connects to all functional modules via onboard traces, responsible for instruction processing, data computation, and system scheduling. Flash memory chip (0.1W): Connected to the main control chip via the SPI bus, it stores program firmware, configuration parameters, and historical acquisition data. Serial port chip (0.02W): Connected to the main control chip via the UART interface, it converts TTL levels to RS232 / RS485 levels for device debugging and external communication. Voltage / temperature conversion chip (0.015W): Connected to the main control chip via an analog SPI interface, it converts the acquired analog voltage and temperature signals into digital signals and transmits them to the main control chip. Current conversion chip (0.85W) and current acquisition module (0.2W): The current acquisition module obtains the current signal through a high-precision sampling resistor, and then the current conversion chip amplifies and converts it into a voltage signal that can be recognized by the main control chip. Optical port driver (0.6W): Connected to the main control chip via a high-speed differential line, it drives the optical module to achieve high-speed, long-distance fiber optic communication. Active crystal oscillator (0.04W): Directly connected to the clock pin of the main control chip, it provides a stable high-frequency clock signal for the entire system. Buzzer (0.2W): Connected to the main control chip via a GPIO interface, it issues an alarm when the system malfunctions (such as overvoltage, overcurrent, or overtemperature). Indicator light (0.1W): Connected to the main control chip via a GPIO interface, it visually displays the system's operating status (such as power, communication, and alarms). Serial port display (0.8W): Connected to the main control chip via a UART interface, it enables human-machine interaction and can display system parameters and alarm information in real time. Figure 6This diagram illustrates the power consumption of the power supply side of a key functional module in the preferred self-powered device of this invention. It primarily handles analog signal acquisition, processing, and power management, while also providing wireless communication extension functionality. It provides a stable power supply for the entire system through an LDO and an analog power module, achieves high-precision signal acquisition and preprocessing through a voltage acquisition module and a temperature operational amplifier, and expands the device's communication methods through a Bluetooth module, enhancing its flexibility and ease of use. The power consumption and functions of its main components are as follows: LDO chip dissipation (0.5W): As a power management unit, it converts the input high-voltage power supply into a stable low-voltage power supply (e.g., 3.3V, 5V) to power all chips on the board. Analog 5V chip dissipation (0.15W): Provides a clean and stable 5V analog power supply to the analog circuit modules on the board, avoiding interference from digital circuit noise on analog signals. Voltage acquisition module (0.18W): Acquires external voltage signals through a voltage divider network and transmits them to the temperature operational amplifier for preliminary processing. Temperature operational amplifier (0.1W): Amplifies and filters the analog signals from the voltage acquisition module and temperature sensor, improving signal accuracy and stability. Optical drive preamplifier (0.3W): with Figure 1 The optical port driver module works in conjunction with the main control chip to provide drive signals and bias voltages to the optical module, enhancing the transmission capability of the optical signal. The Bluetooth module (0.03W) connects to the main control chip via a UART interface, enabling wireless communication between the device and the mobile terminal, supporting remote debugging and data querying. The total power consumption is 4.595W.

[0084] Figure 7 This is a preferred thermoelectric generator unit's operating temperature difference and maximum output power density curve. An excessively low operating temperature difference will result in insufficient output power from the thermoelectric generator unit. In this preferred embodiment, there are two sets of curves. Figure 1 The self-powered device shown uses six thermoelectric generators of 25mm×25mm each. When the temperature of the second cooling surface does not exceed 90°C and the coolant temperature is 25°C, it can generate a maximum of 5.655W of electrical energy.

[0085] Figure 8 The temperature distribution cloud map of the preferred DC solid-state circuit breaker self-powered device of the present invention under steady state shows that, under the rated operating conditions of the power semiconductor module, the highest temperature area is strictly limited to within the safety threshold. The heat dissipation capacity of the main heat dissipation structure is greater than that of the first heat dissipation surface, and there is a significant temperature gradient change in the thickness direction of the thermoelectric power generation unit. This proves that the device can dissipate some heat on the first heat dissipation surface and maintain a considerable temperature difference, thereby ensuring that the thermoelectric power generation unit can continuously and efficiently convert thermal energy into electrical energy through the Seebeck effect.

[0086] Step 4: Figure 9The preferred DC solid-state circuit breaker self-powered device of this invention is shown in the temperature / output power change curve during the cold start stage. The establishment time t1 required for the thermal surface of the thermoelectric generator unit to reach thermal steady state from ambient temperature after the circuit breaker is opened is calculated. The total electrical energy consumed by the key functional modules during this time is calculated using the following formula:

[0087]

[0088] The energy storage capacity of the energy storage unit is determined with a margin of not less than twice that of the energy storage unit. Through the above structure and method, this embodiment fully utilizes the heat loss inevitably generated during the operation of power semiconductor devices, realizing the effective conversion of thermal energy into electrical energy, and constructing a self-powered mechanism decoupled from the electrical state of the DC system. This enables the DC solid-state circuit breaker to reliably perform detection, control, and protection functions even in application scenarios with air-cooling or liquid-cooling conditions but where it is inconvenient to introduce an independent auxiliary power supply.

[0089] Furthermore, the power semiconductor device of this invention employs a double-sided heat dissipation package. The main heat dissipation side (second side) is equipped with a high thermal conductivity air-cooled / liquid-cooled plate (with significantly lower thermal resistance than the energy harvesting side), guiding over 70% of heat loss to be efficiently dissipated via this path, ensuring the chip junction temperature remains within a safe threshold. The energy harvesting side (first side) forms a low thermal resistance continuous path with the thermoelectric generator unit through an insulating thermally conductive interface material (such as high thermal conductivity silicone grease or nano-silver paste), stably maintaining a controllable temperature difference of 30-80℃ under directional heat flow distribution. This design completely avoids the core contradiction of traditional single-sided energy harvesting schemes where "increased thermal resistance in the energy harvesting structure leads to excessive junction temperature," enabling the thermoelectric generator unit to continuously capture waste heat energy while ensuring device reliability. Actual measurements show that under conditions where the second-side cooling surface temperature is ≤90℃, a single thermoelectric generator array can continuously output ≥2.8W of electrical energy. The energy closed-loop system overcomes the dual challenges of "low-voltage start-up" and "transient high power." The unstable millivolt-level electrical energy output from the thermoelectric generator unit is boosted and regulated by a low-voltage start-up DC-DC circuit (start-up threshold ≤50mV) before being stored in a supercapacitor. The energy storage unit is precisely configured according to "thermal difference settling time × module power consumption × 2 times margin" (e.g., if energy consumption is 1.2J within 30 seconds of startup, the energy storage capacity is ≥2.4J), ensuring that the circuit breaker can drive the optocoupler isolation drive module to complete the first disconnection action instantly upon cold start. Under fault conditions, the supercapacitor releases transient high power (peak ≥10W) in milliseconds, prioritizing power supply to the drive and control modules and avoiding protection failure due to insufficient energy. The entire energy flow is physically isolated from the DC bus, completely eliminating the risk of power interruption caused by bus short circuits, voltage drops, or insulation breakdown. The scenario-based design method achieves precise matching of the entire "material-structure-capacity" link. To address the limitations of the circuit breaker's energy extraction temperature difference (ΔT<50℃) and the need for rapid voltage establishment, the traditional material selection logic that only focuses on the zT value is abandoned: bismuth telluride-based materials with high "|S| / κ" are selected to increase the open-circuit voltage (accelerating the start-up of the energy harvesting circuit), or systems with high "S²σ / κ²" are selected to increase power density (reducing the volume of the energy harvesting unit); the thermocouple height is dynamically set according to the cooling conditions (0.8mm for water cooling, 1.5mm for air cooling) to achieve the optimal balance between thermal resistance and power generation efficiency; the load energy consumption during the temperature difference establishment process is calculated by integration (E_req=∫P_load(t)dt), and the energy storage margin is scientifically set to avoid the engineering dilemma of "capacity redundancy increasing volume" or "insufficient capacity leading to start-up failure".

[0090] First, in scenarios such as offshore wind power and remote DC microgrids where "cooling conditions are available but auxiliary power is lacking," the technology frees circuit breakers from dependence on external power supply, improving reliability by over 40% (compared to the failure risk of bus-based power supply solutions during voltage dips). Second, it converts heat loss that previously required forced cooling into functional energy, improving energy utilization efficiency by 15% while avoiding the insulation design complexity and safety hazards introduced by additional power supply circuits. Third, through a power supply priority management strategy (ensuring the drive / control module is protected when energy storage is insufficient), it ensures the stable operation of the core "detection-judgment-disconnection" link throughout its entire lifecycle. This technology addresses the industry pain point of self-powering DC solid-state circuit breakers.

[0091] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0092] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A self-powered DC solid-state circuit breaker based on thermoelectric power generation, characterized in that, It includes, A power semiconductor device employing a double-sided heat dissipation package structure, having a first heat dissipation surface and a second heat dissipation surface arranged opposite to each other; Thermoelectric power generation unit is disposed between the first heat dissipation surface and the cooling medium. It forms a low thermal resistance connection path through an insulating thermally conductive interface material to convert the temperature difference formed by the heat loss generated by the power semiconductor device during the conduction or switching process into electrical energy. An energy harvesting unit is electrically connected to the thermoelectric generator unit to boost and stabilize the electrical energy. An energy storage unit, which is electrically connected to the energy harvesting unit, is used to store processed electrical energy; The power supply control unit is electrically connected to the energy storage unit and supplies power to the DC solid-state circuit breaker in the absence of external auxiliary power. The second heat dissipation surface is connected to the main heat dissipation structure, and the heat dissipation capacity of the main heat dissipation structure is greater than that of the first heat dissipation surface, so as to guide the heat to be dissipated preferentially through the second heat dissipation surface and maintain a temperature difference between the first heat dissipation surface and the cooling medium; the self-powered device has no electrical connection with the DC bus and DC grid during the entire process of energy extraction and power supply.

2. The self-powered DC solid-state circuit breaker based on thermoelectric power generation as described in claim 1, characterized in that, Preferably, the thermoelectric power generation unit is composed of multiple thermoelectric power generation devices connected in series, parallel or mixed, and each thermoelectric power generation device includes multiple pairs of P-type and N-type thermocouples.

3. The self-powered DC solid-state circuit breaker based on thermoelectric power generation as described in claim 1, characterized in that, The main heat dissipation structure is an air-cooled radiator or a liquid-cooled plate; the cooling medium is air, water or insulating coolant.

4. The self-powered DC solid-state circuit breaker based on thermoelectric power generation as described in claim 1, characterized in that, The energy storage unit includes a supercapacitor or a rechargeable battery, configured to store energy during normal operation of the power semiconductor device and release transient high-power electrical energy during initial start-up of the circuit breaker, fault disconnection, or abnormal operating conditions.

5. The self-powered DC solid-state circuit breaker based on thermoelectric power generation as described in claim 1, characterized in that, The power supply control unit supplies power to the functional modules of the DC solid-state circuit breaker in the absence of external auxiliary power. The functional modules include at least one of a current and voltage sensing module, a drive module, a control module, and a fault recording module.

6. The self-powered DC solid-state circuit breaker based on thermoelectric power generation as described in claim 1, characterized in that, The power semiconductor device is a SiC MOSFET module, an IGBT module, or a combination thereof.

7. The self-powering method of the DC solid-state circuit breaker self-powering device based on thermoelectric power generation as described in any one of claims 1-6, characterized in that, It includes, Step S1: Thermoelectric material selection. If high power density is the priority, select a thermoelectric material system with a higher Seebeck coefficient² × electrical conductivity / thermal conductivity² value. If the focus is on high output voltage, select a thermoelectric material system with a higher |Seebeck coefficient| / thermal conductivity value; Step S2: The height of the thermocouple is set according to the cooling conditions: 0.5mm-1.5mm for water cooling, 1mm-3mm for air cooling, and 1.5mm-6mm for natural cooling, in order to optimize the output power density. Step S3: Calculate the number of thermoelectric generators. Based on the total full-load power consumption of the functional modules, the heat loss of power semiconductor devices, cooling conditions, and the conversion efficiency of the thermoelectric generator unit, determine the minimum number of devices required to meet the continuous power supply demand. Step S4: Calculate the establishment time required for the thermal surface of the thermoelectric power generation unit to reach thermal steady state from the ambient temperature after the circuit breaker is opened, and calculate the total electrical energy consumed by the functional modules during this time. Determine the energy storage capacity of the energy storage unit with a margin of not less than 2 times. The self-powered device has no electrical connection with the DC bus and DC grid during the entire process of energy extraction and supply. The second heat dissipation surface is connected to the main heat dissipation structure, guiding the heat to be dissipated preferentially through the second heat dissipation surface, and maintaining a temperature difference between the first heat dissipation surface and the cooling medium, thus constructing a self-powered system decoupled from the electrical state of the DC system.

8. The method as described in claim 7, characterized in that, The thermoelectric material system is a bismuth telluride-based or silver telluride-based material.

9. The method as described in claim 7, characterized in that, In step S4, the thermal steady state is a stable operating state in which the temperature fluctuation of the thermal surface of the thermoelectric generator unit is less than ±2℃.

10. The method as described in claim 7, characterized in that, The thermoelectric power generation unit requires a settling time t1 for its hot surface to reach thermal steady state from ambient temperature, and this is determined based on the power consumption P of the functional module. load Calculate the total electrical energy E consumed during this time using the following formula. req : 。

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