Fuse, converter and photovoltaic system

Abstract

The utility model discloses a fuse, a converter and a photovoltaic system, the fuse comprises a melt, a shell and a thermistor, the melt is arranged in the shell, and the thermistor is arranged outside the shell; and the thermistor is used for detecting the temperature of the fuse. According to the fuse, the thermistor is arranged outside the shell of the fuse, the temperature of the fuse is detected through the thermistor, and when the temperature exceeds the temperature safety range, it is represented that the melt of the fuse is damaged, so that protection of post-stage equipment is achieved.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a fuse, a converter and a photovoltaic system. Background Art

[0002] Fuses are widely used in power electronics. For example, when a short circuit or overcurrent fault occurs in a device, it can damage downstream equipment. To protect downstream equipment, a fuse is connected in series between the upstream and downstream devices. A fuse is a current protector. When the current exceeds a specified value, the fuse generates heat to melt the fuse element, disconnecting the upstream and downstream devices and preventing damage to the electrical equipment due to short circuits or overloads.

[0003] However, due to various unexpected factors such as the fuse's production process, installation deviations, transportation vibrations, etc., the internal fuse element may be damaged. When the internal fuse element is damaged, it may cause the fuse to malfunction or fail, and thus be unable to continue to protect downstream equipment. Utility Model Content

[0004] Based on the above problems, the present application provides a fuse, a converter and a photovoltaic system, aiming to protect downstream equipment.

[0005] The embodiments of this application disclose the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides a fuse, comprising a fuse element, a housing, and a thermistor; the fuse element is disposed inside the housing, and the thermistor is disposed outside the housing;

[0007] The thermistor is configured to detect a temperature of the housing.

[0008] Optionally, it further includes: a comparator and a current limiting resistor;

[0009] The first end of the thermistor is connected to the power supply, the second end of the thermistor is connected to the first input end of the comparator, the second end of the thermistor is connected to the first end of the current limiting resistor, the second end of the current limiting resistor is grounded, and the second input end of the comparator is connected to the voltage corresponding to the temperature reference value; when the relationship between the voltage at the first input end of the comparator and the voltage corresponding to the temperature reference value changes, the output end of the comparator outputs a fault signal corresponding to fuse damage.

[0010] Optionally, the fuse further includes a detection device, a first end of the detection device is connected to the input end of the fuse, and a second end of the detection device is connected to the controller of the protected device;

[0011] When the current at the input end of the fuse flows through the detection device, the detection device sends a fault signal to the controller.

[0012] Optionally, if the fuse is a three-phase fuse, the thermistor includes a first thermistor, a second thermistor and a third thermistor, the first end of the first thermistor is connected to the power supply, the second end of the first thermistor is connected to the first end of the second thermistor, the second end of the second thermistor is connected to the first end of the third thermistor, the second end of the third thermistor is grounded through a current limiting resistor, and the second end of the third thermistor is connected to the first input end of the comparator.

[0013] Optionally, the thermistor is a negative temperature coefficient thermistor or a positive temperature coefficient thermistor.

[0014] Optionally, a first end of the thermistor is connected to a first end of the resistance measuring device, a second end of the thermistor is connected to a second end of the resistance measuring device, and an output end of the resistance measuring device is connected to a controller of the protected device;

[0015] The resistance measuring device is used to obtain the resistance value of the thermistor and send the resistance value to the controller.

[0016] Optionally, the thermistor is arranged at the center of the plane where the detection device is located.

[0017] Optionally, the thermistor is fixed by a fixing device of the detection device.

[0018] In a second aspect, an embodiment of the present application provides a converter, comprising a power conversion circuit and the fuse according to the first aspect;

[0019] The fuse is connected in series in the power conversion circuit.

[0020] In a third aspect, an embodiment of the present application provides a photovoltaic system, comprising: an inverter and at least one fuse according to the first aspect, wherein the at least one fuse is connected to a respective corresponding photovoltaic assembly;

[0021] The inverter is used to receive the DC power output by the corresponding photovoltaic panels and invert the DC power into AC power to supply power to the load.

[0022] The fuse provided in this application includes a fuse element, a housing, and a thermistor. The fuse element is disposed inside the housing, and the thermistor is disposed outside the housing. The thermistor is used to detect the temperature of the housing. Thus, by disposing a thermistor outside the fuse housing, the temperature of the fuse is detected by the thermistor. When the temperature exceeds the safe temperature range, it indicates that the fuse element is damaged, thereby identifying the damage of the fuse element and protecting downstream equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1 A schematic structural diagram of a fuse provided in an embodiment of the present application;

[0025] Figure 2 A schematic diagram of a thermistor configuration according to an embodiment of the present application;

[0026] Figure 3 A schematic structural diagram of another fuse provided in an embodiment of the present application;

[0027] Figure 4 A structural diagram of another fuse provided in an embodiment of the present application;

[0028] Figure 5a A schematic structural diagram of another fuse provided in an embodiment of the present application;

[0029] Figure 5b A structural diagram of another fuse provided in an embodiment of the present application;

[0030] Figure 6 A schematic diagram of parameter changes of a fuse provided in an embodiment of the present application;

[0031] Figure 7 A schematic structural diagram of another fuse provided in an embodiment of the present application;

[0032] Figure 8 A schematic structural diagram of a photovoltaic system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] Fuses are widely used in power electronics. For example, when a short circuit or overcurrent fault occurs in a device, it can damage downstream equipment. To protect downstream equipment, a fuse is connected in series between the upstream and downstream devices. A fuse is a current protector. When the current exceeds a specified value, the fuse generates heat to melt the fuse element, disconnecting the upstream and downstream devices and preventing damage to the electrical equipment due to short circuits or overloads.

[0034] However, due to various unexpected factors such as the fuse's production process, installation deviations, transportation vibrations, etc., the internal fuse element may be damaged. When the internal fuse element is damaged, it may cause the fuse to malfunction or fail, and thus be unable to continue to protect downstream equipment.

[0035] As an example, if the fuse element is partially damaged, the fuse is in a conductive state. However, due to the partial damage to the fuse element, the resistance of the fuse changes, which in turn affects the current flowing through the fuse. This may affect the normal operation of the system (for example, the current flowing through becomes smaller and the fuse will blow before reaching the preset current), and it will not be able to protect the subsequent equipment.

[0036] To address the above issues, embodiments of the present application provide a fuse, a converter, and a photovoltaic system. The fuse includes a fuse element, a housing, and a thermistor. The fuse element is disposed inside the housing, and the thermistor is disposed outside the housing. The thermistor is used to detect the temperature of the fuse.

[0037] In this way, the present application sets a thermistor outside the fuse housing and uses the thermistor to detect the temperature of the fuse. When the temperature exceeds the temperature reference value, it indicates that the fuse element is damaged, thereby protecting the subsequent equipment.

[0038] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0039] See also Figure 1 , which is a structural diagram of a fuse provided in an embodiment of the present application, combined with Figure 1 As shown, the fuse provided in the embodiment of the present application may include: a fuse 101 , a shell 102 and a thermistor 103 ; wherein the fuse 101 is arranged inside the shell 102 , and the thermistor 103 is arranged outside the shell 102 .

[0040] A fuse, also known as a fusible link or fuse, is an electrical device that operates on the principle of the thermal effect of electric current. When the current in the circuit exceeds the rated current of the fuse, the fuse generates a large amount of heat, melting itself, thereby achieving the purpose of disconnecting the circuit. In some possible implementations, fuses can be divided into various types based on their structure, material, and usage scenarios, including but not limited to the following types: porcelain plug fuses, spiral fuses, enclosed fuses, filler fuses, self-resetting fuses, and so on.

[0041] The fuse element is the core component of a fuse, responsible for interrupting the flow of current. When the current in the circuit exceeds the fuse element's rated value, the fuse element overheats and melts, shutting off the circuit and preventing further current from increasing and damaging equipment. Fuse elements are typically made of two materials: one made of a low-melting-point material like lead, lead-tin alloy, or zinc, and used in low-current circuits; the other made of a higher-melting-point metal like silver or copper, used in high-current circuits.

[0042] The fuse casing is a protective layer, usually made of insulating material, that prevents arcing or fault current from harming the surrounding environment. The casing also holds and protects the fuse element.

[0043] A thermistor is a sensor resistor whose resistance changes with temperature. Typically made from materials such as ceramics, polymers, and semiconductor single crystals, thermistors are extremely sensitive to temperature. Thermistors operate based on the thermal effect, where the resistivity of semiconductor materials varies significantly with temperature. Thermistors are temperature-sensitive devices that exploit this property.

[0044] Thermistors can be categorized by their temperature-dependent characteristics into positive temperature coefficient (PTC) thermistors and negative temperature coefficient (NTC) thermistors. Positive temperature coefficient (PTC) thermistors increase in resistance as temperature rises and are used for overcurrent and overtemperature protection. Negative temperature coefficient (NTC) thermistors decrease in resistance as temperature rises and are used for temperature measurement and control.

[0045] In one possible implementation, the thermistor of the embodiment of the present application may be an NTC resistor. Since the NTC resistor can provide a resistance value change that is linear or approximately linear with temperature, it is suitable for high-precision temperature measurement and control systems, and can ensure the accuracy and reliability of the measurement.

[0046] The thermistor 103 is configured to detect the temperature of the housing 102 .

[0047] It should be understood that using a thermistor to detect the temperature of the fuse housing indirectly reflects the temperature of the fuse element. If the fuse element is intact and operating normally, the fuse temperature will remain within the preset temperature range. If the current in the circuit where the fuse is located is too high, the fuse temperature will rise. When the temperature of the fuse exceeds the preset temperature range, the fuse will melt, achieving the purpose of protecting downstream equipment.

[0048] However, if the fuse element is damaged, such as if part of the element breaks (not completely, current can flow), the resistance of the fuse will increase, causing the fuse to continue to withstand excessive current, which may cause heat accumulation and lead to a sharp increase in temperature. As an example, assume that the current flowing through the fuse is I, the power consumption of the fuse is P, and the resistance of the fuse is R 熔 , then the power consumption of the fuse is as follows (1):

[0049] P=I 2 R 熔 ;Formula (1)

[0050] Combined with formula (1), it can be seen that when the fuse element breaks (not completely broken, current can flow), the resistance of the fuse will increase, the power consumption of the fuse will increase, and heat accumulation will occur, causing the temperature to rise sharply.

[0051] When the temperature reaches the melting point of the melt, it will melt and form a fracture, which may be accompanied by the generation of an arc. If the arc cannot be controlled promptly and effectively, it may cause arc spraying, posing a threat to surrounding equipment and the environment.

[0052] Therefore, in the embodiment of the present application, by arranging a thermistor on the outside of the fuse casing, when the temperature of the fuse rises due to damage to the fuse element, the thermistor can detect the temperature of the fuse in time, and when the temperature of the fuse exceeds the temperature reference value, it is considered that the fuse element is damaged, thereby achieving rapid positioning of the fuse fault and further improving the safety and reliability of the subsequent equipment.

[0053] At the same time, in the embodiment of the present application, when the fuse element is not damaged and the fuse blows normally, heat will also be generated. The thermistor can still detect the temperature of the fuse and consider the fuse to be damaged when the temperature of the fuse exceeds the temperature reference value (the damage at this time is the normal blowing of the fuse). Compared with setting up a separate detection device for fuse blowing feedback, the hardware cost and implementation cost of the present application are lower than the cost of setting up a separate detection device, which reduces the cost while ensuring timely blowing feedback.

[0054] Based on the fuse provided in the above embodiment, in a possible implementation, see Figure 2 The thermistor 103 can be set at the center of the plane where the detection device is located.

[0055] A detection device refers to a device used to detect the blowing of a fuse. For example, the detection device can be a feedback node, with a fuse connected in parallel to the feedback node. When the fuse blows, it assumes a high-impedance state, the input current flows through the feedback node loop, the feedback node pops open, and a fault signal is transmitted to a controller, which then shuts down the equipment protected by the fuse.

[0056] In this implementation, the original detection device of the fuse can be replaced with a thermistor, and the thermistor is used to detect the fuse. Therefore, the thermistor can be set at the center of the plane where the original detection device is located.

[0057] It should be understood that by arranging the thermistor at the center position, the temperature detected by the thermistor can be closer to the temperature of the melt, thereby improving the accuracy of the detection.

[0058] In a possible implementation, the thermistor 103 is fixed by a fixing device of the detection device.

[0059] The fixing device refers to a device for fixing the detection device. It should be understood that the original fuse is generally provided with a detection device. In the embodiment of the present application, the original detection device can be replaced by a thermistor, and the thermistor can be fixed by the fixing device originally used to fix the detection device.

[0060] In one possible implementation, the fixing means may include screws and fixing bars (eg Figure 2 As shown), the thermistor is pressed and fixed on the fuse housing using a fixing strip, and both ends of the fixing strip are fixed to the fuse housing by screws. The fixing strip can be a metal strip, a metal plate, etc., and is not specifically limited here.

[0061] It should be understood that in the embodiments of the present application, a thermistor can replace the detection device, and the fixture of the detection device on the original side of the fuse can be used. Using diagonal screws and the fixture, the thermistor is clamped at the center and tightly attached to the center of the side of the fuse. Compared to setting up a separate detection device for fuse blown feedback, the hardware cost and implementation cost of the embodiments of the present application are lower than that of setting up a separate detection device, reducing costs while ensuring timely fuse blown feedback.

[0062] Based on the fuse provided in the above embodiment, in a possible implementation, see Figure 3 The present application also provides a fuse, which includes a fuse element 101, a shell 102, a thermistor 103, a comparator 301 and a current-limiting resistor 302; wherein, the fuse element 101 is arranged inside the shell 102, and the thermistor 103 is arranged outside the shell 102; the first end of the thermistor 103 is connected to the power supply Us, the second end of the thermistor 103 is connected to the first input end of the comparator 301, the second end of the thermistor 103 is connected to the first end of the current-limiting resistor 302, and the second end of the current-limiting resistor 302 is grounded; the second input end of the comparator 301 is connected to the voltage Ur corresponding to the temperature reference value.

[0063] When the magnitude relationship between the voltage at the first input terminal of the comparator 301 and the voltage corresponding to the temperature reference value changes, the output terminal of the comparator 301 outputs a fault signal corresponding to damage of the melt 101 .

[0064] A comparator is an electronic device or circuit that compares the magnitude of two voltages and outputs a corresponding signal based on the comparison result.

[0065] The current limiting resistor mainly plays the role of limiting the current in the circuit to protect other components in the circuit from being damaged by excessive current.

[0066] The power supply refers to a power supply that provides voltage to the thermistor. In a possible implementation, the power supply can be provided by a control system of the converter.

[0067] The fault signal refers to a signal indicating that the fuse element of the fuse is damaged, such as a high-level signal or a low-level signal.

[0068] It should be understood that the voltage at the first input terminal of the comparator 301 is obtained based on the voltage of the power supply, the thermistor, and the current limiting resistor. As an example, assuming that the power supply is Vcc, the resistance of the thermistor is R1, the resistance of the current limiting resistor is R2, and the voltage at the first input terminal of the comparator is Uin, then Uin can be calculated using the following formula (2):

[0069] Uin=Vcc×R2 / (R1+R2); formula (2)

[0070] It can be seen from formula (2) that the voltage of Uin changes with the resistance of thermistor R1.

[0071] The temperature reference value refers to the temperature value of the fuse casing during normal operation, which can also be understood as the upper limit of the safe temperature range.

[0072] The voltage corresponding to the temperature reference value refers to the voltage inputted by the second input terminal corresponding to the upper limit of the safe temperature of the fuse housing. In a possible implementation, the voltage corresponding to the temperature reference value may be provided by a control system of the converter.

[0073] The change in magnitude relationship means that the magnitude of the comparison between the voltage at the first input terminal and the voltage corresponding to the temperature reference value changes, for example, the voltage at the first input terminal changes from being greater than the voltage corresponding to the temperature reference value to being less than the voltage corresponding to the temperature reference value.

[0074] It should be understood that in the embodiment of the present application, when the magnitude relationship between the voltage at the first input terminal and the voltage corresponding to the temperature reference value changes, it can be considered that the temperature of the fuse housing has exceeded the upper limit of the safe temperature range. At this time, the output terminal of the comparator can output a fault signal corresponding to fuse damage to realize the identification of the fuse.

[0075] In one possible implementation, when the thermistor is a negative temperature coefficient thermistor (NTC resistor), the resistance of the NTC resistor will decrease as the temperature increases. At this time, the voltage at the first input terminal will increase as the NTC resistance decreases. When the voltage at the first input terminal exceeds the voltage corresponding to the temperature reference value, the output of the comparator flips and outputs a fault signal corresponding to fuse damage.

[0076] In another possible implementation, when the thermistor is a positive temperature coefficient thermistor (PTC resistor), the resistance of the PTC resistor will increase with increasing temperature. At this time, the voltage of the first input terminal will decrease as the PTC resistance increases. When the voltage of the first input terminal is less than the voltage corresponding to the temperature reference value, the output of the comparator flips and outputs a fault signal corresponding to fuse damage.

[0077] It should be understood that the power supply provides voltage to the thermistor, and the voltage output from the common end of the thermistor and the current-limiting resistor is input to the first input end of the comparator. When the fuse blows normally or the fuse element is damaged, the temperature of the fuse rises, the resistance of the thermistor changes, and thus causes the voltage at the first input end to change. The voltage of the first input end is compared with the voltage corresponding to the temperature reference value of the second input end, and the comparator outputs a fault signal based on the comparison result.

[0078] In an embodiment of the present application, a comparator compares the output voltage of the thermistor with the voltage corresponding to the temperature reference value, and outputs a fault signal based on the comparison result, thereby achieving rapid identification of fuse faults and ensuring the accuracy of the comparison results.

[0079] Based on the fuse provided in the above embodiment, in a possible implementation, see Figure 4 In addition to the fuse element 101, the housing 102 and the thermistor 103, the fuse may further include a detection device 401. The first end of the detection device 401 is connected to the input end of the fuse, and the second end of the detection device 401 is connected to the controller of the protected device.

[0080] When the current at the input end of the fuse flows through the detection device 401 , the detection device 401 sends a fault signal to the controller.

[0081] The protected device refers to a device or circuit provided with a fuse, such as a converter, etc., and is not specifically limited here.

[0082] The controller refers to a device that controls the protected device. The controller can be the controller of the protected device itself or the controller of the system where the protected device is located. There is no specific limitation here.

[0083] It should be understood that in the embodiment of the present application, in addition to setting up a thermistor, a detection device will also be set up to detect whether the fuse is blown. When the fuse element is normal, if the fuse element is blown, the detection device can send a fault signal to the controller to indicate that the fuse is blown, and the thermistor can also detect the temperature of the fuse. When the temperature exceeds the temperature reference value, it is determined that the fuse element is damaged (the damage at this time is normal melting), realizing dual judgment of the fuse, ensuring the reliability of the fuse, and the safety of the subsequent equipment.

[0084] In one possible implementation, detection device 401 can also be used to detect the resistance of a fuse element. When the resistance of the fuse element exceeds a preset resistance range, the fuse element is determined to be damaged. Furthermore, detection device 401 can perform fuse detection during a system detection phase before the system in which the fuse element is installed is operating, or during a power-down phase after the system has ceased operation. The detection timing of detection device 401 is not limited herein.

[0085] When the fuse element is damaged and there is no fault in the circuit, the detection device may not be triggered. Therefore, it is necessary to use a thermistor to detect the temperature of the fuse. Then, when the temperature exceeds the temperature reference value, it is determined that the fuse element is damaged, ensuring the safety and reliability of the downstream equipment, while avoiding damage to the circuit or equipment where the fuse is located.

[0086] Based on the fuse provided in the above embodiment, in a possible implementation, see Figure 5a If the fuse is a three-phase fuse, the fuse includes a fuse element 101, a housing 102, a thermistor 103 and a current-limiting resistor 302. The thermistor 103 includes a first thermistor 501, a second thermistor 502 and a third thermistor 503. The first end of the first thermistor 501 is connected to the power supply, the second end of the first thermistor 501 is connected to the second end of the second thermistor 502, the third end of the second thermistor 502 is connected to the first end of the third thermistor 503, the second end of the third thermistor 503 is grounded through the current-limiting resistor 302, and the second end of the third thermistor 503 is connected to the first input end of the comparator 301.

[0087] A three-phase fuse is a circuit protection device consisting of three fuses, each connected to a phase line, forming a circuit protection system. When an overload or short circuit occurs in the circuit, the three-phase fuse automatically cuts off the current to protect the electrical equipment from damage.

[0088] In an embodiment of the present application, the first thermistor, the second thermistor and the third thermistor are respectively used to detect the temperature of the corresponding fuse. By connecting the first thermistor, the second thermistor, the third thermistor and the current limiting resistor in series and grounding the current limiting resistor, the voltage on the current limiting resistor can be measured to reflect the temperature of the fuse, and then determine whether the fuse element or the current flowing through the fuse itself exceeds the specified requirements. That is, the second end of the third thermistor is connected to the first input end of the comparator, and the comparator obtains a comparison result by comparing the voltage of the current limiting resistor with the voltage corresponding to the temperature reference value, and outputs a signal (normal signal or fault signal) according to the comparison result.

[0089] As an example, assume that the first thermistor, the second thermistor, and the third thermistor are all NTC resistors, the voltage corresponding to the temperature reference value and the resistance of the current-limiting resistor are fixed values, and when the fuse is normal, the comparator outputs a low-level signal; when current flows through the fuse, the fuse will heat up, and the resistance of the first thermistor, the second thermistor, and the third thermistor will decrease. The voltage input to the first input terminal of the comparator is expressed by the following formula (1):

[0090]

[0091] Wherein, Uin represents the voltage of the first input terminal of the input comparator, R represents the current limiting resistor, Ra represents the first thermistor, Rb represents the second thermistor, Rc represents the third thermistor, and Us represents the voltage of the power supply.

[0092] Combining formula (2), we can see that Uin will increase with temperature. When the temperature of the fuse is greater than the temperature reference value, Uin will be greater than the voltage Ur corresponding to the temperature reference value. At this time, the comparator flips and outputs a high-level signal (i.e., a fault signal). The voltage of Us can be provided by the converter control system.

[0093] Based on the fuse provided in the above embodiment, in another possible implementation, see Figure 5b If the fuse is a three-phase fuse, the fuse includes a fuse element 101, a housing 102, a thermistor 103 and a current-limiting resistor 302. The thermistor 103 includes a first thermistor 501, a second thermistor 502 and a third thermistor 503. There are three comparators 301. A first end of the first thermistor 501 is connected to a power supply, a second end of the first thermistor 501 is grounded via the current-limiting resistor 302, and a second end of the first thermistor 501 is connected to a first input end of the comparator 301. Similarly, the connection method of the second thermistor 502 and the third thermistor 503 is the same as that of the first thermistor 501.

[0094] It should be understood that by individually identifying each phase of a three-phase fuse, the accuracy of identifying the fuses corresponding to a single phase can be improved.

[0095] Based on the above example, see Figure 6 , which is a schematic diagram of parameter changes of a fuse provided in an embodiment of the present application, Figure 6 T in 参考值 Indicates the temperature reference value, T 温度 Indicates the temperature of the fuse, R NTC represents the sum of the first thermistor, the second thermistor, and the third thermistor, Uin represents the voltage at the first input terminal of the input comparator, Ur represents the voltage corresponding to the temperature reference value, V out Indicates the level status of the comparator.

[0096] Combine Figure 6 As shown, when T 温度 Increased, R NTC The resistance value will decrease, and Uin will increase. After time t, T 温度 >T 参考值 , and Uin>Ur, then V out The output signal will change from 0 to 1 (0 indicates a normal signal, 1 indicates a fault signal).

[0097] It should be understood that in the embodiment of the present application, for a three-phase fuse, by connecting the first thermistor, the second thermistor, the third thermistor and the current limiting resistor in series and grounding the current limiting resistor, the voltage on the current limiting resistor can be measured to reflect the temperature condition of the three-phase fuse, which can achieve a quick judgment on the damage of the fuse element, improve the safety and reliability of the equipment, and the cost is lower than setting up three detection devices separately.

[0098] Based on the fuse provided in the above embodiment, in a possible implementation, Figure 7 As shown, based on the fuse including the fuse element 101, the housing 102 and the thermistor 103, the first end of the thermistor 103 can also be connected to the first end of the resistance measuring device 701, the second end of the thermistor 103 is connected to the second end of the resistance measuring device 701, and the output end of the resistance measuring device 701 is connected to the controller of the protected device.

[0099] The resistance measuring device is used to obtain the resistance value of the thermistor 103 and send the resistance value to the controller.

[0100] It should be understood that the resistance measuring device refers to a device used to measure the resistance of a thermistor, such as a multimeter, a bridge, an ohmmeter, a clamp ammeter, a resistance tester, etc., which is not specifically limited here.

[0101] It should be understood that in the embodiments of the present application, the resistance value of the thermistor can also be used to directly reflect whether the fuse has blown or the fuse element is damaged. Since the resistance value of the thermistor changes with the temperature of the fuse, when the fuse has blown normally or the fuse element is damaged, the resistance value of the thermistor will exceed a reference resistance value. Therefore, the resistance value of the thermistor can be sent to the controller. When the resistance value of the thermistor exceeds the reference resistance value, the controller directly controls the protected equipment to shut down. The reference resistance value refers to the resistance value of the thermistor when the fuse is operating normally.

[0102] In this embodiment, the controller can compare the received resistance value with the reference resistance value to determine whether the resistance value of the thermistor exceeds the reference resistance value; when the resistance value of the thermistor does not exceed the reference resistance value, the protected device operates normally; when the resistance value of the thermistor exceeds the reference resistance value, the protected device is controlled to shut down, thereby protecting the protected device and improving the safety and reliability of subsequent equipment.

[0103] An embodiment of the present application further provides a converter, comprising a power conversion circuit and a fuse as described in any of the above embodiments; wherein the fuse is connected in series in the power conversion circuit.

[0104] The present application also provides a photovoltaic system. Figure 8 The system 800 includes an inverter 801 and at least one fuse 802 as described in any of the above embodiments, and the at least one fuse 802 is connected to a corresponding photovoltaic component.

[0105] The inverter 801 is used to receive the direct current output by the corresponding photovoltaic module and invert the direct current into alternating current to supply power to the load.

[0106] The inverter is the core device of a photovoltaic system. Its primary function is to convert the direct current (DC) output of photovoltaic panels into alternating current (AC) suitable for use by the power grid. In some implementations, the inverter also monitors parameters such as current, voltage, and frequency in the solar photovoltaic system, adjusting them based on system requirements to ensure normal operation.

[0107] The "first" and "second" (if any) in the names mentioned in the embodiments of this application are only used as name identifiers and do not represent the first or second in order.

[0108] The above is merely one specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A fuse, characterized in that: The fuse includes a fuse element, a shell and a thermistor; the fuse element is arranged inside the shell, and the thermistor is arranged outside the shell; The thermistor is configured to detect a temperature of the housing; The fuse also includes a comparator connected to the thermistor, the comparator being configured to compare an output voltage of the thermistor with a voltage corresponding to a temperature reference value, and the comparator outputting a fault signal corresponding to damage of the fuse element; the temperature reference value being an upper limit value of a safe temperature of the housing of the fuse; or, The thermistor is connected to a controller, and the controller is configured to control the protected device to shut down when the resistance value of the thermistor exceeds a reference resistance value; the reference resistance value is the resistance value corresponding to the thermistor when the fuse is operating normally.

2. The fuse according to claim 1, characterized in that Also includes: Current limiting resistor; The first end of the thermistor is connected to a power supply, the second end of the thermistor is connected to a first input end of the comparator, the second end of the thermistor is connected to a first end of the current limiting resistor, the second end of the current limiting resistor is grounded, and the second input end of the comparator is connected to a voltage corresponding to a temperature reference value; when the magnitude relationship between the voltage at the first input end of the comparator and the voltage corresponding to the temperature reference value changes, the output end of the comparator outputs a fault signal corresponding to melt damage.

3. The fuse according to claim 1, wherein: The fuse further includes a detection device, a first end of the detection device is connected to the input end of the fuse, and a second end of the detection device is connected to the controller of the protected device; When the current at the input end of the fuse flows through the detection device, the detection device sends a fault signal to the controller.

4. The fuse according to claim 2, wherein: If the fuse is a three-phase fuse, the thermistor includes a first thermistor, a second thermistor, and a third thermistor. The first end of the first thermistor is connected to the power supply, the second end of the first thermistor is connected to the first end of the second thermistor, the second end of the second thermistor is connected to the first end of the third thermistor, the second end of the third thermistor is grounded via a current limiting resistor, and the second end of the third thermistor is connected to the first input end of the comparator.

5. The fuse according to any one of claims 1 to 4, characterized in that: The thermistor is a negative temperature coefficient thermistor or a positive temperature coefficient thermistor.

6. The fuse according to any one of claims 1 to 4, characterized in that: The controller is a controller of the protected device, a first end of the thermistor is connected to a first end of a resistance measuring device, a second end of the thermistor is connected to a second end of the resistance measuring device, and an output end of the resistance measuring device is connected to the controller of the protected device; The resistance measuring device is used to obtain the resistance value of the thermistor and send the resistance value to the controller of the protected device.

7. The fuse according to claim 1 or 2, characterized in that: The thermistor is arranged at the center of the plane where the detection device is located.

8. The fuse according to claim 1 or 2, characterized in that: The thermistor is fixed by a fixing device of the detection device.

9. A converter, characterized in that: comprising a power conversion circuit and a fuse according to any one of claims 1 to 8; The fuse is connected in series in the power conversion circuit.

10. A photovoltaic system, characterized in that: include: An inverter and at least one fuse according to any one of claims 1 to 8, wherein the at least one fuse is connected to a respective corresponding photovoltaic module; The inverter is used to receive direct current (DC) output by the corresponding photovoltaic module and invert the DC into alternating current (AC) to supply power to the load.

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