Photovoltaic direct current overvoltage protection miniature circuit breaker

Abstract

The application discloses a photovoltaic direct-current overvoltage protection micro circuit breaker, which comprises a circuit breaker box body, a temperature sensing foot, a thermal expansion component, a Hall monitoring ring, a magnetic core, a non-ferromagnetic part and a reset elastic part; the temperature sensing foot is used for sensing the temperature of a photovoltaic panel or an inverter and transmitting heat to the thermal expansion component; the thermal expansion component is expanded after being heated, and then pushes the magnetic core to move along the axial direction, so that the Hall monitoring ring detects the change of the magnetic field intensity and continuously adjusts the photovoltaic output power; when the magnetic core moves to a low magnetic force area or the non-ferromagnetic part corresponds to the Hall monitoring ring, a control module drives an integrated contact mechanism to act, and the direct-current circuit is rapidly disconnected. The application combines temperature sensing, magnetic field detection, power adjustment and circuit protection, realizes the gradual control of the photovoltaic system from pre-adjustment to circuit protection, and improves the operation safety, protection reliability and long-term stability of the photovoltaic system.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation protection technology, specifically a photovoltaic DC overvoltage protection miniature circuit breaker. Background Technology

[0002] Most existing photovoltaic DC circuit breakers employ electronic monitoring and control methods. These methods use temperature sensors, current sensors, voltage detection modules, and microprocessors to collect operating parameters in real time and control relays, electromagnetic tripping mechanisms, or electronic switches to perform circuit breaking protection based on the detection results. While this approach achieves a certain degree of intelligent protection, it is highly dependent on electronic components. In photovoltaic systems subjected to prolonged exposure to high temperatures, humidity, dust, electromagnetic interference, and lightning surges, the accuracy of electronic detection can easily drift, leading to decreased stability of the control module. This can even result in malfunctions, failures to operate, or protection delays, affecting the long-term stable operation of the photovoltaic system.

[0003] In addition, existing protection methods usually adopt the working mode of directly disconnecting the circuit after reaching the set threshold. In the early stage of the fault, there is a lack of gradual adjustment capability. When the temperature of the photovoltaic module gradually rises or the system load changes continuously, it is impossible to adjust the inverter output power in advance according to the abnormal development process. It can only implement hard disconnection after the protection conditions are met. This not only easily causes power generation interruption, but also the frequent start and stop will increase the workload of the inverter and circuit breaker contacts, reducing the operating efficiency and service life of the entire photovoltaic system.

[0004] In view of this, we have studied and improved the existing problems to provide a photovoltaic DC overvoltage protection miniature circuit breaker to solve the current problems. The aim is to solve the problems and improve the practical value through this technology. Summary of the Invention

[0005] This invention aims to solve the problems of existing photovoltaic DC protection devices, which mainly rely on current or voltage parameters for protection. These devices are unable to respond in a timely manner when photovoltaic modules overheat, inverters continue to heat up, or abnormal operating conditions begin. They can only implement circuit breaking protection after a fault occurs, which can easily lead to continuous heating of devices, large power fluctuations, and insufficient system reliability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A photovoltaic DC overvoltage protection miniature circuit breaker includes a circuit breaker housing, a temperature-sensing foot, a thermotropic component, a Hall effect monitoring ring, a magnetic core, a non-ferromagnetic component, and a reset elastic component. The circuit breaker housing serves as an integral mounting and load-bearing structure. The temperature-sensing foot is located on the outside or side of the circuit breaker housing and is used to sense the temperature of the photovoltaic panel or inverter. The thermotropic component is located inside the circuit breaker housing, with one end thermally connected to the temperature-sensing foot, forming a sealed thermal expansion cavity inside, and the other end connected to the magnetic core via a push rod. The magnetic core is axially movable, forming magnetic pole regions at both ends and a low-magnetic-force region or a zero-magnetic-force region in the middle. The non-ferromagnetic component is fixed to one end of the magnetic core. The reset elastic component is located on one side of the magnetic core and is used to provide a reset force. The Hall effect monitoring ring is annularly sleeved around the outer periphery of the magnetic core, and its output end is electrically connected to a control module and an inverter voltage regulation module. The circuit breaker housing also has an integrated contact mechanism that is linked to the signal of the Hall effect monitoring ring.

[0007] With the above structure, the temperature sensing foot can directly sense the temperature change of the photovoltaic module or inverter, and drive the magnetic core to move through the thermotropic component, so that the Hall monitoring ring can detect the magnetic field change in real time, realizing the conversion of temperature change into magnetic field change. Then, the control module completes the inverter voltage regulation and circuit breaking control, so that the protection action changes from simple fault disconnection to a combination of pre-regulation and circuit breaking, improving the safety and continuity of the entire photovoltaic system operation.

[0008] In a preferred embodiment, the Hall effect monitoring loop output is electrically connected to the control module. The control module controls the inverter voltage regulation module to adjust the inverter transformation ratio based on the magnetic field strength signal output by the Hall effect monitoring loop, thereby continuously adjusting the photovoltaic output power. When the magnetic field begins to weaken, the control module first reduces the photovoltaic output power to reduce system heat generation, achieving active buffer control before the fault further develops and reducing the power surge caused by direct circuit interruption.

[0009] In a preferred embodiment, a small detection air gap is formed between the Hall monitoring ring and the magnetic core, or a low-friction guiding structure is provided to ensure a stable detection gap during the axial movement of the magnetic core, thereby improving the Hall detection accuracy, reducing motion resistance, and improving the stability of long-term operation.

[0010] In a preferred embodiment, the magnetic core is further configured such that strong magnetic regions are formed at both ends, and low magnetic or zero magnetic regions are formed in the middle. A non-ferromagnetic component is fixedly installed at one end of the magnetic core. When the magnetic core moves, the Hall monitoring ring sequentially detects the strong magnetic region, the low magnetic region, and the non-ferromagnetic region, so that the output magnetic field signal forms a continuously changing curve. The control module can execute different control strategies according to different magnetic field change stages, realizing a gradual control process from voltage regulation control to circuit breaking protection.

[0011] In a preferred embodiment, the thermotropic component is further configured such that it adopts an independent sealed cavity structure filled with a thermal expansion medium. When the temperature sensing foot detects an increase in temperature, it pushes the magnetic core to move. When the temperature returns to normal, the thermotropic component contracts and, in conjunction with the reset elastic element, restores the magnetic core to its initial position. This allows the entire mechanism to complete automatic reset without an independent drive device, improving the reliability of the device and reducing structural complexity.

[0012] In a preferred embodiment, the temperature sensing foot is further configured to adopt a high thermal conductivity metal patch or thermal fin structure, which can be directly attached to the photovoltaic module frame, busbar, inverter heat sink or other heat-generating parts, so that heat can be quickly transferred to the thermotropic component, improving the temperature response speed and shortening the protection response time.

[0013] In a preferred embodiment, the circuit breaker housing is further configured to have a modular structure, with aluminum alloy heat dissipation fins and a labyrinthine ventilation channel on the back or side. It also supports DIN rail mounting and multi-pole splicing, and can be configured into single-pole, bipolar, and multi-pole protection modules according to different photovoltaic systems, thereby improving product versatility and installation convenience.

[0014] The beneficial effects achieved by this invention are as follows: 1. In this invention, the temperature-driven axial movement of the magnetic core is achieved through the structural cooperation of the temperature-sensing foot, the thermotropic component, and the magnetic core. Combined with the Hall monitoring ring for accurate detection of the magnetic field position, the inverter's transformation ratio can be adjusted in real time and continuously, thereby realizing automatic optimization and stable control of photovoltaic output power and effectively improving the system's power generation efficiency.

[0015] 2. In this invention, a pure structural control method with thermal and magnetic position coupling is adopted. When the temperature-related state is abnormal, the power limiting buffer adjustment can be quickly performed through the control module, avoiding the system interruption caused by the frequent hard disconnection of traditional circuit breakers, and significantly improving the operation stability and service life of the photovoltaic system.

[0016] 3. In this invention, the structure is highly integrated, requiring no additional electromagnetic drive device. It features simple structure, low cost, high reliability, and convenient maintenance. At the same time, through modular box design and heat dissipation structure, it adapts to the application requirements of complex outdoor photovoltaic environments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present invention; Figure 2 This is a schematic diagram of a cross-sectional structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the control circuit according to an embodiment of the present invention.

[0018] Figure label: 1. Temperature sensing foot; 2. Circuit breaker housing; 3. Thermotropic component; 4. Hall effect monitoring ring; 5. Magnetic core; 6. Non-ferromagnetic component; 7. Reset elastic component. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0020] It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the invention.

[0021] The following describes, with reference to the accompanying drawings, some embodiments of a photovoltaic DC overvoltage protection miniature circuit breaker provided by the present invention.

[0022] like Figure 1 and Figure 3 As shown, a photovoltaic DC overvoltage protection miniature circuit breaker of this embodiment includes a temperature sensing foot 1, a circuit breaker housing 2, a thermotropic component 3, a Hall effect monitoring ring 4, a magnetic core 5, a non-ferromagnetic component 6, and a reset elastic component 7.

[0023] The circuit breaker housing 2 serves as the overall mounting structure and is preferably made of flame-retardant insulating engineering plastic through a single injection molding process. Its interior forms a cavity for housing the thermally extensible assembly 3, the magnetic core 5, and the integrated contact mechanism. A DIN rail mounting structure is provided on one side or the back of the circuit breaker housing 2 for easy installation in photovoltaic combiner boxes, inverter distribution cabinets, or DC power distribution systems. Furthermore, aluminum alloy heat dissipation fins are provided on the back or side wall of the circuit breaker housing 2, forming a labyrinthine ventilation channel to improve the heat dissipation capacity of the device during long-term operation while ensuring insulation protection performance.

[0024] The temperature sensing foot 1 is located on the outside of the circuit breaker box 2. It is preferably made of copper alloy, high thermal conductivity aluminum alloy or graphite composite thermal conductive material. It can be made into a patch type, fin type or arc surface bonding structure. It can be directly attached to the photovoltaic module frame, busbar, inverter heat sink, inductor or other heat-prone parts by thermal grease, thermal pad or thermal adhesive, so that heat can be quickly transferred to the thermotropic component 3.

[0025] The thermotropic expansion assembly 3 is installed inside the circuit breaker housing 2 and is a completely sealed thermal expansion drive mechanism. It forms a sealed cavity filled with a thermal expansion medium with a high coefficient of volume expansion. This thermal expansion medium can be silicone oil, liquid paraffin, heat-sensitive wax, low-melting-point organic materials, or other thermal expansion media. One end of the thermotropic expansion assembly 3 is thermally connected to the temperature sensing foot 1 via a thermally conductive connection, and the other end is equipped with a push rod. The push rod is fixedly connected to or abuts against the magnetic core 5. When the temperature changes, the volume change of the thermal expansion medium pushes the push rod to produce axial displacement.

[0026] The magnetic core 5 is disposed within the guide channel inside the circuit breaker housing 2 and can reciprocate along the axial direction. The magnetic core 5 is preferably made of a soft magnetic material with high permeability. Magnetic pole regions are formed at both ends, and a low-magnetic-force region or a zero-magnetic-force region is formed in the middle. The low-magnetic-force region can be formed by designing the magnetic circuit to create a demagnetizing area, or by using a local demagnetizing structure. The magnetic core 5 is cylindrical in shape, with a small clearance between its outer diameter and the guide hole to ensure stable movement of the magnetic core and reduce movement resistance.

[0027] The non-ferromagnetic component 6 is fixedly disposed at one end of the magnetic core 5. It can be made of non-ferromagnetic materials such as copper, aluminum, stainless steel, ceramics, and polymer insulating materials. When the magnetic core 5 moves to the predetermined position, the non-ferromagnetic component 6 can enter the detection area of ​​the Hall monitoring ring 4, so that the detection magnetic field of the Hall monitoring ring 4 is further reduced or even approaches zero, thereby forming a more obvious change in the control signal and improving the detection reliability and anti-interference ability.

[0028] The reset elastic element 7 is disposed on one side of the magnetic core 5. It is preferably a compression spring, with one end abutting against the inner wall of the circuit breaker housing 2 and the other end abutting against the magnetic core 5. When the thermotropic component 3 does not push the magnetic core 5, the reset elastic element 7 always applies a reset force to the magnetic core 5 to keep the magnetic core 5 in its initial position. When the thermotropic component 3 drives the magnetic core 5 to move, the reset elastic element 7 is compressed and stores energy. After the temperature returns to normal, it pushes the magnetic core 5 back to its initial position.

[0029] In this embodiment, the Hall monitoring ring 4 has a closed ring structure and is sleeved around the outer periphery of the magnetic core 5, forming a detection air gap of 0.1 to 0.3 mm between it and the magnetic core 5. Alternatively, a low-friction bearing, a PTFE guide sleeve, or a wear-resistant sliding sleeve can be installed between them to reduce friction and improve the stability of the magnetic field detection. The Hall monitoring ring 4 internally houses a Hall detection chip and a signal processing circuit, with its output terminals connected to the control module and the inverter voltage regulation module, respectively.

[0030] In this embodiment, the circuit breaker housing 2 is also provided with an integrated contact mechanism, which includes a moving contact, a stationary contact, an arc-extinguishing chamber, and a drive mechanism. The drive mechanism can be linked with the magnetic core 5, or the control module can drive the actuator to perform the action. When the output of the Hall monitoring ring 4 reaches the preset threshold, the control module controls the contact mechanism to quickly disconnect the main circuit to achieve DC circuit breaking protection.

[0031] In this embodiment, the control module receives the magnetic field strength signal output by the Hall monitoring loop 4 and calculates the current position of the magnetic core 5 in real time. It then outputs corresponding control strategies based on different magnetic field strengths. When the magnetic field strength is within the normal range, the control module controls the inverter voltage regulation module to maintain normal operation. When the magnetic field begins to decrease, the control module first controls the inverter voltage regulation module to adjust the inverter's operating parameters, continuously regulating the photovoltaic system's output power to reduce device temperature rise. When the magnetic field further decreases to the circuit breaker threshold, the control module immediately controls the integrated contact mechanism to activate, achieving circuit breaker protection.

[0032] The working process of this invention is as follows: When the photovoltaic system is working normally, the temperature of the photovoltaic module and inverter is within the normal range. The temperature sensing foot 1 detects the normal temperature and transfers the heat to the thermotropic component 3. At this time, the thermotropic component 3 maintains its initial elongation state, the reset elastic element 7 is in its natural state, the magnetic core 5 is in the initial detection position, and the Hall monitoring ring 4 corresponds to the strong magnetic pole region of the magnetic core 5. Therefore, the Hall monitoring ring 4 detects a high magnetic field strength and continuously outputs a normal magnetic field signal to the control module.

[0033] The control module determines that the system is working normally based on the output signal of Hall monitoring loop 4, controls the inverter voltage regulation module to maintain the predetermined transformation ratio, so that the inverter maintains normal power output and the entire circuit breaker remains in the conducting state.

[0034] When the photovoltaic module is exposed to the sun for a long time, local hot spots are formed, or the internal components of the inverter are abnormally heated, the temperature sensing foot 1 quickly senses the temperature change and transfers the heat to the thermotropic component 3. The thermal expansion medium inside the thermotropic component 3 begins to expand, pushing the push rod to drive the magnetic core 5 to move gradually along the axial direction.

[0035] As the magnetic core 5 moves, the detection area of ​​the Hall monitoring ring 4 gradually transitions from the strong magnetic pole region of the magnetic core 5 to the low magnetic force region. At this time, the output magnetic field strength of the Hall monitoring ring 4 continuously decreases. The control module judges that the system has entered the over-temperature warning state based on the magnetic field change trend, and sends an adjustment signal to the inverter voltage regulation module to make the inverter adjust the transformation ratio, reduce the output power or limit the output current, so as to alleviate the temperature rise of the photovoltaic module and the inverter, thereby avoiding the system from immediately shutting down and improving the system's continuous operation capability.

[0036] If the ambient temperature continues to rise, the thermotropic component 3 further pushes the magnetic core 5 to move, causing the non-ferromagnetic component 6 to enter the detection area of ​​the Hall monitoring ring 4. The output signal of the Hall monitoring ring 4 further decreases to below the circuit breaking threshold. The control module confirms that the system has entered a dangerous state and immediately drives the integrated contact mechanism to move, causing the moving contact to quickly separate from the stationary contact. At the same time, it works with the DC arc extinguishing chamber to complete the arc extinguishing, realizing the rapid disconnection of the photovoltaic DC circuit, thereby avoiding the continuous expansion of overvoltage and overtemperature that could damage the equipment.

[0037] As the ambient temperature gradually decreases, the thermal expansion medium inside the thermotropic component 3 gradually contracts, the push rod retracts, and under the action of the reset elastic element 7, the magnetic core 5 gradually returns to its initial position. The Hall monitoring ring 4 detects the strong magnetic field area again, and the control module confirms that the system has returned to normal. According to the set program, the inverter voltage regulation module is allowed to gradually restore normal output. When the reclosing conditions are met, the integrated contact mechanism can be controlled to close again, so that the system can restore normal power supply.

[0038] In a preferred embodiment, the Hall monitoring loop 4 outputs an analog signal for continuous detection. The control module establishes a correspondence between magnetic field strength and temperature change based on the Hall voltage change, thereby enabling continuous adjustment of the inverter output power instead of just two-stage control. This makes the entire protection process smoother and helps reduce power fluctuations in the photovoltaic system.

[0039] In a preferred embodiment, the thermotropic component 3 can use different combinations of thermal expansion media to form different operating temperatures, making the circuit breaker suitable for photovoltaic systems of different power levels and different ambient temperatures.

[0040] In a preferred embodiment, the circuit breaker housing 2 adopts a standard modular structure. Multiple adjacent circuit breakers can be connected by a side splicing structure to form a two-pole, three-pole, or four-pole protection module. Each module can share a control module or be controlled independently to achieve synchronous protection of multiple photovoltaic branches and improve the operational safety of the entire photovoltaic power generation system.

[0041] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A photovoltaic DC overvoltage protection miniature circuit breaker, characterized in that, It includes a circuit breaker housing (2), a temperature sensing foot (1), a thermotropic component (3), a Hall effect monitoring ring (4), a magnetic core (5), a non-ferromagnetic component (6), and a reset elastic component (7). The circuit breaker housing (2) is an integral load-bearing structure; The temperature sensing foot (1) is located outside or on the side of the circuit breaker box (2) and is used to sense the temperature of the photovoltaic panel or inverter. The thermo-expansion component (3) is installed inside the circuit breaker box (2), with one end thermally connected to the temperature sensing foot (1), and the inside filled with a sealed thermal expansion liquid. The other end is connected to the magnetic core (5) through a push rod. The magnetic core (5) is axially movable inside the circuit breaker housing (2), with magnetic poles at both ends and a low magnetic force area or zero magnetic force area in the middle. The non-ferromagnetic component (6) is fixed to one end of the magnetic core (5); The reset elastic element (7) is disposed on one side of the magnetic core (5) and is used to provide a reset force; The Hall monitoring ring (4) is ring-shaped and sleeved on the outer periphery of the middle part of the magnetic core (5), and its end is electrically connected to the inverter voltage regulation module; The circuit breaker housing (2) is also equipped with an integrated contact mechanism that is linked to the signal of the Hall monitoring ring (4).

2. The photovoltaic miniature circuit breaker according to claim 1, characterized in that, It also includes a control module for controlling the photovoltaic inverter. The output of the Hall monitoring ring (4) is electrically connected to the control module. The control module adjusts the inverter's transformation ratio according to the magnetic field strength signal output by the Hall monitoring ring (4), thereby realizing automatic and continuous adjustment of the photovoltaic output power.

3. The photovoltaic miniature circuit breaker according to claim 2, characterized in that, When the Hall monitoring ring (4) is facing the strong magnetic pole region of the magnetic core (5) under normal working conditions, it outputs a higher magnetic field strength signal to the control module. The control module reduces the inverter transformation ratio to achieve the set output power. When the magnetic core (5) moves to align the low magnetic field region or non-ferromagnetic component (6) with the Hall monitoring ring (4), it outputs a lower magnetic field strength signal. The control module first increases the transformation ratio to limit the power buffer, and then drives the integrated contact mechanism to disconnect the circuit.

4. The photovoltaic miniature circuit breaker according to claim 1, characterized in that, A small air gap or a low-friction bearing is provided between the Hall monitoring ring (4) and the magnetic core (5).

5. The photovoltaic miniature circuit breaker according to claim 1, characterized in that, The temperature sensing foot (1) is a high thermal conductivity metal patch or fin structure, which can be directly or through a thermally conductive medium bonded to the surface of the photovoltaic device.

6. The photovoltaic miniature circuit breaker according to claim 1, characterized in that, When the Hall monitoring ring (4) is facing the strong magnetic pole region of the magnetic core (5) under normal working conditions, it outputs a signal to control the inverter voltage regulation module to reduce the transformation ratio and realize the photovoltaic output power setting adjustment; when the magnetic core (5) moves to align the low magnetic area or non-ferromagnetic component (6), it outputs a circuit breaker signal to disconnect the circuit.

7. The photovoltaic miniature circuit breaker according to claim 1, characterized in that, The thermotropic component (3) is an independent sealed cavity. When the temperature sensing foot (1) senses the temperature rise, it pushes the magnetic core (5) to move, so that the Hall monitoring ring (4) detects the low magnetic field and triggers power regulation or circuit breaking protection. When the temperature drops, the thermotropic component (3) contracts and cooperates with the reset elastic element (7) to align the non-ferromagnetic element (6) with the Hall monitoring ring (4) to achieve undercurrent or low temperature protection.

8. The photovoltaic miniature circuit breaker according to claim 1, characterized in that, The circuit breaker box (2) adopts a modular structure, with aluminum alloy heat dissipation fins and ventilation labyrinth channels on the back or side, supporting DIN rail installation and multi-pole splicing.

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