Inverter DC terminal temperature early warning method, device and photovoltaic inverter system

Abstract

This application discloses a method, device, and photovoltaic inverter system for early warning of DC terminal temperature of an inverter. The method includes: collecting the current temperature and current current of each terminal branch of the inverter; determining the temperature anomaly alarm mode for each terminal branch based on the current temperature, current current, and target temperature setpoint; and controlling the operating state of each terminal branch according to the temperature anomaly alarm mode. The technical solution provided by this application determines multiple temperature anomaly alarm modes for each terminal branch based on the current temperature, current current, and target temperature setpoint. This allows for timely control of the operating state of each terminal branch based on its different temperature anomaly alarm modes, thereby controlling the temperature of each terminal branch as early as possible. The method of this application provides timely and effective detection, improving the sensitivity of temperature warning and solving the problems of low sensitivity and detection lag in existing technologies.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic power generation technology, and in particular to an inverter DC terminal temperature early warning method, device and photovoltaic inverter system. Background Art

[0002] The purpose of measuring the temperature of the inverter input terminals is to provide early warning of abnormal voltage compression or contact of the photovoltaic connector, which may cause high contact resistance, heat and burn the terminals or directly cause arcing, leading to serious faults.

[0003] The terminal temperature measurement method currently used is mainly to collect the temperature value and compare the temperature value with the maximum operating temperature threshold. When the temperature value is greater than the maximum operating temperature threshold, the over-temperature alarm is triggered. Since the maximum operating temperature threshold is the maximum temperature at which the inverter can work normally, when the over-temperature alarm is triggered, the entire inverter must be shut down. Therefore, the existing terminal temperature measurement method has low sensitivity and detection lag, which results in the problem that once the over-temperature is triggered, the entire inverter can only be shut down. Summary of the invention

[0004] The present application provides an inverter DC terminal temperature early warning method, device and photovoltaic inverter system to solve the problems of low sensitivity and delayed detection in the prior art.

[0005] According to one aspect of the present application, a method for early warning of inverter DC terminal temperature is provided, comprising:

[0006] Collect the current temperature and / or current of each terminal branch of the inverter;

[0007] Determining a temperature abnormality alarm mode for each of the terminal branches according to each of the current temperatures, each of the current currents, and a target temperature setting value;

[0008] According to each of the temperature abnormality alarm modes, the operating state of each of the terminal branches is controlled.

[0009] Optionally, determining the abnormal temperature alarm mode of each terminal branch according to each current temperature, each current current and a target temperature setting value includes:

[0010] Calculate the average value of the current temperatures of all terminal branches and the temperature difference of each terminal branch according to each current temperature and each current current;

[0011] According to each of the current temperatures, each of the temperature differences, the average value and the target temperature setting value, a temperature abnormality alarm mode of each of the terminal branches is determined.

[0012] Optionally, the calculating, according to each of the current temperatures and each of the current currents, an average value of the current temperatures of all the terminal branches and a temperature difference of each of the terminal branches comprises:

[0013] The theoretical temperature under the current current, a first temperature difference between the current temperature and the theoretical temperature, an average value of the current temperatures of all terminal branches, and a second temperature difference between the current temperature of each terminal branch and the average value are calculated.

[0014] Optionally, the target temperature setting value includes a first target temperature setting value;

[0015] Determining the temperature abnormality alarm mode of each terminal branch according to each current temperature, each temperature difference, the average value and the target temperature setting value includes:

[0016] Determining whether the current temperature is greater than or equal to the first target temperature setting value;

[0017] If the current temperature is greater than or equal to the first target temperature setting value, it is determined that the temperature abnormality alarm mode of the terminal branch is a fault mode.

[0018] Optionally, the target temperature setting value further includes a second target temperature setting value;

[0019] Determining the temperature abnormality alarm mode of each terminal branch according to each current temperature, each temperature difference, the average value and the target temperature setting value includes:

[0020] determining whether the first temperature difference is greater than the second target temperature setting value;

[0021] If the first temperature difference is greater than the second target temperature setting value, it is determined that the temperature abnormality alarm mode of the terminal branch is the first alarm mode.

[0022] Optionally, the target temperature setting value further includes a third target temperature setting value; and determining the temperature abnormality alarm mode of each terminal branch according to each of the current temperatures, each of the temperature differences, the average value, and the target temperature setting value includes:

[0023] determining whether the second temperature difference is greater than the third target temperature setting value;

[0024] If the second temperature difference is greater than the third target temperature setting value, it is determined that the temperature abnormality alarm mode of the terminal branch is the second alarm mode.

[0025] Optionally, determining the abnormal temperature alarm mode of each terminal branch according to each current temperature, each temperature difference, the average value and the target temperature setting value includes:

[0026] In the second alarm mode, determining whether the first temperature difference is greater than a second target temperature setting value;

[0027] If, in the second alarm mode, the first temperature difference is greater than the second target temperature setting value, it is determined that the temperature abnormality alarm mode of the terminal branch is the third alarm mode.

[0028] Optionally, according to each of the abnormal temperature alarm modes, controlling the operating state of each of the terminal branches includes:

[0029] The inverter is controlled to shut down and each of the terminal branches is closed, or the operating power of the boost module in the terminal branch corresponding to each of the abnormal temperature alarm modes is controlled to remain unchanged or to be closed.

[0030] According to another aspect of the present application, there is provided an early warning device for the DC terminal temperature of an inverter, comprising:

[0031] A collection module, which is used to collect the current temperature and current of each terminal branch of the inverter;

[0032] A determination module, the determination module is used to determine the temperature abnormality alarm mode of each of the terminal branches according to each of the current temperatures, each of the current currents and a target temperature setting value;

[0033] A control module, the control module is used to control the operating state of each of the terminal branches according to each of the temperature abnormality alarm modes.

[0034] According to another aspect of the present application, a photovoltaic inverter system is provided, comprising:

[0035] At least two input circuits, the input circuits comprising input terminals and a boost module, the input terminals being connected in series with the boost module;

[0036] an inverter module, the inverter module being connected to each of the boost modules; and

[0037] In the early warning device described in any embodiment of the present application, the acquisition module of the early warning device is connected to each of the input terminals, and the control module of the early warning device is connected to the boost module and the inverter module.

[0038] The technical solution provided in the embodiment of the present application collects the current temperature and current current of each terminal branch of the inverter; determines the temperature abnormality alarm mode of each terminal branch based on the current temperature and current current; and controls the operating status of each terminal branch based on the temperature abnormality alarm mode. The technical solution provided by the embodiment of the present application obtains a first comparison result by comparing the current temperature with the warning value, and determines whether the temperature abnormality alarm mode of each terminal branch is the maximum value warning mode according to the first comparison result; compares the temperature difference between the collected current temperature and the calculated theoretical temperature under the current current with the target temperature setting value to obtain a second comparison result, and determines whether the temperature abnormality alarm mode of each terminal branch is the steady-state warning mode according to the second comparison result; calculates the average value of the current temperatures of all terminal branches and the temperature difference between the current temperature of each terminal branch and the average value, and compares the temperature difference with the target temperature setting value to obtain a third comparison result, and determines whether the temperature abnormality alarm mode of each terminal branch is the dynamic warning mode according to the third comparison result and the judgment result of whether it is in the steady-state warning mode at this time, so as to timely control the operating state of each terminal branch according to different temperature abnormality alarm modes, so as to realize pre-warning and control of multiple warning modes, and can control the temperature of each terminal branch as early as possible, instead of controlling and protecting only based on the protection threshold obtained at the maximum allowable operating temperature, and the detection is timely and the sensitivity is effectively improved, which solves the problems of low sensitivity and detection lag in the prior art.

[0039] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present application, nor is it intended to limit the scope of the present application. Other features of the present application will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. 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 creative work.

[0041] Figure 1 A flowchart of an inverter DC terminal temperature early warning method provided in an embodiment of the present application;

[0042] Figure 2 A temperature collection and control principle diagram of a DC terminal of an inverter provided in an embodiment of the present application;

[0043] Figure 3 A flowchart of another inverter DC terminal temperature early warning method provided in an embodiment of the present application;

[0044] Figure 4 A schematic diagram of the mechanism of an inverter DC terminal temperature early warning device provided in an embodiment of the present application;

[0045] Figure 5 A schematic structural diagram of an electronic device for an inverter DC terminal temperature early warning method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0047] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] Figure 1 This is a flowchart of an inverter DC terminal temperature early warning method provided in an embodiment of the present application. This embodiment can be used to solve the low sensitivity and detection lag in terminal temperature measurement. The early warning method can be executed by an inverter DC terminal temperature early warning device, which can be implemented in the form of hardware and / or software. The early warning device can be configured in any electronic device with communication function. Figure 1 , the early warning method includes:

[0049] S110, collecting the current temperature and current of each terminal branch of the inverter.

[0050] Specifically, see Figure 2 , Figure 2 A temperature collection and control principle diagram of an inverter DC terminal provided in an embodiment of the present application, comprising Figure 2It can be seen that each inverter has multiple input terminals, and each input terminal branch is provided with a temperature acquisition module, a current acquisition module, a boost module and an inverter module. The temperature acquisition module, the current acquisition module, the boost module and the inverter module are connected in sequence, and the current temperature and current current of each terminal of the inverter are collected by the temperature acquisition module and the current acquisition module, and the collected current temperature and current current of each terminal branch of the inverter are transmitted to the microcontroller (Microcontroller Unit, MCU), and the MCU calculates and judges the collected data and realizes the control of the boost module and the inverter module of each terminal branch. Exemplarily, the temperature acquisition module can be a temperature collector such as a thermocouple, and the current acquisition module can be a current sensor, which is not limited here.

[0051] S120, determining a temperature abnormality alarm mode for each terminal branch according to each current temperature, each current current, and a target temperature setting value.

[0052] Optionally, multiple calculated temperature values ​​can be determined according to each current temperature and / or each current current, and each calculated temperature value can be compared with each target temperature setting value, so as to determine the temperature abnormality alarm mode of each terminal branch according to each comparison result. Specifically, each current temperature is used as the first calculated temperature value, and each first calculated temperature value is compared with the first temperature setting value to obtain a first comparison result. According to each first comparison result, it is determined whether the temperature abnormality alarm mode of each terminal branch is a fault mode (maximum value warning mode). It can be understood that the first temperature setting value here can be the maximum temperature warning value; according to each current temperature and each current current, an equivalent relationship between the temperature and the current size is established, and the theoretical temperature under the current current is calculated based on the equivalent relationship. The temperature difference between each current temperature collected and the calculated theoretical temperature under the current current is used as the second calculated comparison value, and each second calculated comparison value is compared with the second target temperature setting value to obtain a second comparison result. According to each second comparison result, it is determined whether the temperature abnormality alarm mode of each terminal branch is the first alarm mode (steady-state warning mode). It can be understood that the second target temperature setting value can be the current temperature. The maximum acceptable temperature difference between the actual temperature of the inverter and the theoretical temperature can be determined, which can be determined according to the specific application environment, model, required sensitivity and false alarm rate of the inverter, and is not limited here; the average value of the current temperature of all terminal branches is calculated, and the temperature difference between the current temperature of each terminal branch and the average value is used as the third calculation comparison value, and the third calculation comparison is compared with the third target temperature setting value to obtain a third comparison result. According to the third comparison result and the judgment result of whether it is in the steady-state warning mode at this time, it is determined whether the temperature abnormality alarm mode of each terminal branch is the second alarm mode (dynamic warning mode) and / or the third alarm mode. It can be understood that the third target temperature setting value can be the maximum acceptable difference between the actual temperature and the average temperature of the terminal branch of the inverter, which can be determined according to the specific application environment, model, required sensitivity and false alarm rate of the inverter, and is not limited here. Among them, the equivalent relationship is formed by testing the temperature values ​​under different currents, and a data table is formed, and the relationship between temperature and current is obtained by curve fitting. Considering the processing speed of the digital signal processor (DSP), the second-order formula is generally used. As shown in the following formula:

[0053] Tnom=k1I 2 +k2I+k3;

[0054] In the formula, k1, k2, and k3 are obtained by curve fitting. It is understandable that the equivalent relationship of different inverters is inconsistent. The k1, k2, and k3 are closely related to the circuit, structural design, and heat dissipation design of the inverter itself. In specific applications, the equivalent relationship can be obtained by fitting the big data through multiple tests.

[0055] S130. Control the operating status of each terminal branch according to each abnormal temperature alarm mode.

[0056] It is understandable that the operation state of each terminal branch can be timely controlled according to the different abnormal temperature alarm modes of each terminal, which may include: when the temperature of the terminal branch is normal and no alarm is triggered, the terminal branch is controlled to operate normally; when the terminal branch triggers the abnormal temperature alarm mode, the operating power of the terminal branch can be controlled to decrease or remain unchanged; the terminal branch can also be controlled to be closed or all terminal branches are closed, the entire inverter is shut down, etc. Specifically, in one embodiment, when the abnormal temperature alarm mode is the maximum value warning mode, the inverter is controlled to shut down and the boost module and the inverter module in each terminal branch are turned off; when the abnormal temperature alarm mode is the steady-state warning mode, the MCU controls the operating power of the boost module in the terminal branch to remain unchanged, specifically, the MCU can control the boost module power set value not to increase to achieve the control of the operating power of the boost module of the terminal branch to remain unchanged; when the abnormal temperature alarm mode is the dynamic warning mode, the MCU controls the boost module power set value not to increase and closes the boost module in the terminal branch when it is in the steady-state warning mode.

[0057] The technical solution provided in the embodiment of the present application determines a variety of temperature abnormality alarm modes for each terminal branch according to each current temperature, each current current, and a target temperature setting value, so that the operating status of each terminal branch can be timely controlled according to the different temperature abnormality alarm modes of each terminal branch, thereby controlling the temperature of each terminal branch as early as possible, and detecting in a timely manner and effectively improving the sensitivity of the temperature warning, thereby solving the problems of low sensitivity and delayed detection in the prior art.

[0058] It can be understood that in this embodiment, multiple calculated temperature values ​​are determined according to each current temperature and / or each current current, and the multiple calculated temperature values ​​are compared with multiple target temperature setting values ​​to obtain multiple comparison results, thereby determining multiple temperature abnormality alarm modes for each terminal branch based on the multiple comparison results, so that the operating status of each terminal branch can be controlled in time according to the different temperature abnormality alarm modes of each terminal branch, so as to control the temperature of each terminal branch as early as possible to achieve pre-warning and control of multiple warning modes, rather than only controlling and protecting based on the protection threshold obtained at the maximum allowable operating temperature, which effectively improves the sensitivity and solves the problems of low sensitivity and detection lag in the prior art.

[0059] It can be understood that this embodiment obtains a first comparison result by comparing the current temperature with the warning value, and determines whether the temperature abnormality alarm mode of each terminal branch is the maximum value warning mode according to the first comparison result; compares the temperature difference between the collected current temperature and the calculated theoretical temperature under the current current with the second target temperature setting value to obtain a second comparison result, and determines whether the temperature abnormality alarm mode of each terminal branch is a steady-state warning mode according to the second comparison result; calculates the average value of the current temperatures of all terminal branches and the temperature difference between the current temperature of each terminal branch and the average value, compares the temperature difference with the third target temperature setting value to obtain a third comparison result, and determines whether the temperature abnormality alarm mode of each terminal branch is a dynamic warning mode according to the third comparison result and the judgment result of whether it is in the steady-state warning mode at this time, thereby controlling the operating state of each terminal branch according to different temperature abnormality alarm modes to achieve pre-warning and control of multiple warning modes, rather than only controlling and protecting based on the protection threshold obtained at the maximum allowable operating temperature, effectively improving the sensitivity, and solving the problems of low sensitivity and detection lag in the prior art.

[0060] Figure 3 This is a flow chart of another inverter DC terminal temperature early warning method provided in an embodiment of the present application. The embodiment of the present application further refines the above embodiment on the basis of the above embodiment. Figure 3 , the early warning method includes:

[0061] S210: Collect the current temperature and current of each terminal branch of the inverter.

[0062] S220, calculating an average value of the current temperatures of all terminal branches and a temperature difference of each terminal branch according to each current temperature and each current current.

[0063] It is understandable that the theoretical temperature of each terminal branch can be calculated by each current current, and then the temperature difference between the terminal branch and the theoretical temperature can be calculated, and the temperature difference is the first temperature difference; the average value of the current temperature of all terminal branches is calculated, and then the temperature difference between each terminal branch and the average value is calculated as the second temperature difference. The aforementioned multiple calculated temperature values ​​include each current temperature, each first temperature difference, each second temperature difference, etc.

[0064] Optionally, in one embodiment, step S220 includes:

[0065] S221: Calculate the theoretical temperature under the current current, the first temperature difference between the current temperature and the theoretical temperature, the average value of the current temperatures of all terminal branches, and the second temperature difference between the current temperature of each terminal branch and the average value.

[0066] The temperature difference includes a first temperature difference and a second temperature difference; the theoretical temperature under the current current can be calculated by the following formula:

[0067] Tnom=k1I 2 +k2I+k3; where Tnom is the theoretical temperature and I is the current current.

[0068] S222: The difference obtained by subtracting the current temperature from the theoretical temperature is the first temperature difference between the current temperature and the theoretical temperature; the ratio obtained by adding up the current temperatures of all the collected terminal branches and dividing it by the number of branches is the average value of the current temperatures of all the terminal branches; the difference obtained by subtracting the current temperature of each terminal branch from the average value is the second temperature difference between the current temperature of each terminal branch and the average value.

[0069] After step S220, the early warning method further includes:

[0070] S230, determining the temperature abnormality alarm mode of each terminal branch according to each current temperature, each temperature difference, the average value and the target temperature setting value.

[0071] It is understandable that the target temperature setting value includes multiple target temperature setting values, such as the aforementioned first target temperature setting value, the second target temperature setting value, the third target temperature setting value, etc. The multiple temperature abnormality alarm modes of each terminal branch can be determined according to the comparison result between the current temperature and the first target temperature setting value, the comparison result between the temperature difference and the second target temperature setting value, the difference between the current temperature and the average value, and the table result between the current temperature and the average value. The multiple temperature abnormality alarm modes can be alarms submitted according to the alarm level hierarchy, or parallel alarm modes.

[0072] Optionally, in one embodiment, step S230 includes:

[0073] S231a: Determine whether the current temperature is greater than or equal to the first target temperature setting value;

[0074] S231b: If the current temperature is greater than or equal to the first target temperature setting value, determine that the temperature abnormality alarm mode of the terminal branch is a fault mode.

[0075] Among them, the target temperature setting value includes the first target temperature setting value; the first target temperature is the protection value at the maximum operating temperature, the first target temperature setting value is negatively correlated with the sensitivity and the false alarm rate, the smaller the first target temperature setting value is, the higher the sensitivity is, and the probability of false alarm increases; the larger the first target temperature setting value is, the lower the sensitivity is, the probability of false alarm is also reduced, and the alarm will be delayed, generally 15-20℃.

[0076] Optionally, when it is determined that the temperature abnormality alarm mode of the terminal branch is a fault mode, a first fault signal can be generated and transmitted to the terminal at the same time. After receiving the first fault signal, the terminal performs an audible and visual alarm to remind the operation and maintenance personnel. The audible and visual alarm in the fault mode can be a red light, because this fault is the most serious fault condition and needs to be paid enough attention by the operation and maintenance personnel, otherwise it will cause serious faults, such as arcing or even fire. Therefore, at this time, the operation and maintenance personnel must rush to the site as soon as possible to check the equipment condition. If the current temperature is less than the first target temperature setting value, the program ends.

[0077] Optionally, in one embodiment, step S230 further includes:

[0078] S232a: Determine whether the first temperature difference is greater than the second target temperature setting value;

[0079] S232b: If the first temperature difference is greater than the second target temperature setting value, determine that the temperature abnormality alarm mode of the terminal branch is the first alarm mode.

[0080] Among them, the target temperature setting value also includes the second target temperature setting value. The second target temperature setting value is also negatively correlated with the sensitivity and false alarm rate. The smaller the second target temperature setting value is, the higher the sensitivity is and the higher the probability of false alarm is. The larger the second target temperature setting value is, the lower the sensitivity is, the lower the probability of false alarm is, the alarm will be delayed, and the average temperature will be referred to. At the same time, branches with large deviations will be eliminated. The value is generally 10-15°C.

[0081] Optionally, when it is determined that the temperature abnormality alarm mode of the terminal branch is the first alarm mode, a second fault signal can be generated at the same time and transmitted to the terminal. After receiving the second fault signal, the terminal will issue an audible and visual alarm to remind the operation and maintenance personnel. At this time, the operation and maintenance personnel need to conduct on-site inspections. After the inspection is correct, the fault can be eliminated; if the first temperature difference is greater than the second target temperature setting value, the program operation ends.

[0082] Optionally, in one embodiment, step S230 further includes:

[0083] S233a: Determine whether the second temperature difference is greater than the third target temperature setting value;

[0084] S233b: If the second temperature difference is greater than the third target temperature setting value, determine that the temperature abnormality alarm mode of the terminal branch is the second alarm mode.

[0085] Optionally, when it is determined that the temperature abnormality alarm mode of the terminal branch is the second alarm mode, a third fault signal can be generated at the same time and transmitted to the terminal. After receiving the third fault signal, the terminal will issue an audible and visual alarm to remind the operation and maintenance personnel to bring relevant equipment for on-site inspection.

[0086] Optionally, in one embodiment, step S230 further includes:

[0087] S233c: In the second alarm mode, determine whether the first temperature difference is greater than the second target temperature setting value;

[0088] S233d: If, in the second alarm mode, the first temperature difference is greater than the second target temperature setting value, determining that the temperature abnormality alarm mode of the terminal branch is the third alarm mode.

[0089] Optionally, when it is determined that the temperature abnormality alarm mode of the terminal branch is the third alarm mode, a fourth fault signal can be generated and transmitted to the terminal at the same time. After receiving the fourth fault signal, the terminal will sound an audible and visual alarm to remind maintenance personnel to check the abnormal situation on site as soon as possible. After the inspection is correct, the fault can be eliminated; if the second temperature difference is less than or equal to the average value, the program ends. If in the second alarm mode, the first temperature difference is less than or equal to the second target temperature setting value, the program ends. It can be understood that the audible and visual alarms caused by the first fault signal, the second fault signal, the third fault signal, and the fourth fault signal are audible and visual alarms of different modes, which can be specifically divided according to the corresponding fault level.

[0090] After step S230, the early warning method further includes:

[0091] S240. Control the operating status of each terminal branch according to each abnormal temperature alarm mode.

[0092] Optionally, according to each abnormal temperature alarm mode, controlling the operating state of each terminal branch includes:

[0093] The inverter is controlled to shut down and each terminal branch is closed, or the operating power of the boost module in the terminal branch corresponding to each abnormal temperature alarm mode is controlled to remain unchanged or be closed.

[0094] Specifically, in the fault mode, the inverter is controlled to shut down and the boost module and inverter module in each terminal branch are turned off; through the fault mode, each terminal branch is protected in a timely and effective manner and serious faults such as arcing or even fire can be avoided. In the first alarm mode, the operating power of the boost module in the control terminal branch remains unchanged; the first alarm mode compares the first temperature difference with the second target temperature setting value, identifies the branch with a difference between the first temperature difference and the second target temperature setting value, controls the operating power of the boost module in the control terminal branch to remain unchanged, and timely controls the temperature of the terminal branch to avoid the rapid rise of the temperature of the terminal branch, and reminds the user to pay attention in time, which plays the role of warning the customer to pay attention in advance. In the second alarm mode, the operating power of the boost module in the control terminal branch remains unchanged; in the third alarm mode, the boost module in the control terminal branch is turned off. The second alarm mode compares the second temperature difference with the average value, specifically extracts the branch with abnormal temperature, and timely controls the temperature of the corresponding terminal branch, and warns the customer to pay attention in advance, and then cooperates with the third alarm mode to further determine the fault branch and protect it in time.

[0095] The technical solution provided in the embodiment of the present application provides temperature warning from different dimensions, and issues warnings and protections for the urgency of abnormal terminal temperature through level one faults and level three alarms. When the temperature control is not completely out of control, the operating status of the faulty terminal branch is promptly controlled to control its temperature. When there is a possibility that the terminal branch temperature is completely out of control, the corresponding branch or inverter is promptly shut down. Through this multi-level and multi-dimensional temperature warning and control, advance warning and control of multiple warning modes are achieved, and detection is more timely and sensitive, rather than the prior art that only controls and protects based on the protection threshold obtained at the maximum allowable operating temperature. Compared with the prior art solutions, the present application further effectively improves the sensitivity and real-time detection.

[0096] Figure 4 A schematic diagram of the mechanism of an inverter DC terminal temperature warning device provided in an embodiment of the present application, see Figure 4 The early warning device includes: a collection module 310, a determination module 320 and a control module 330.

[0097] It is understandable that the acquisition module 310 is used to collect the current temperature and current of each terminal branch of the inverter. For specific acquisition steps, see step S110 in the above embodiment. Optionally, the acquisition module 310 can also be used to execute step S210 in the above embodiment, which is not described here.

[0098] The determination module 320 is used to determine the temperature abnormality alarm mode of each terminal branch according to each current temperature, each current current and the target temperature setting value. The specific determination process can be referred to step S120 in the above embodiment. Optionally, the determination module 320 is also used to execute step S220 and step S230 in the above embodiment; wherein, step S220 specifically includes step S221 and step S222 in the above embodiment; step S220 specifically includes step S231a, step S231b, step S232a, step S232b, step S233a, step S233b, step S233c and step S233d in the above embodiment, which will not be repeated here.

[0099] The control module 330 is used to control the operating status of each terminal branch according to the abnormal temperature alarm mode. The specific control process can be seen in step S130 in the above embodiment. Optionally, the control module 330 is also used to execute step S240 in the above embodiment, which is not repeated here.

[0100] An inverter DC terminal temperature early warning device provided in an embodiment of the present application can execute an inverter DC terminal temperature early warning method provided in any embodiment of the present application, and has functional modules and beneficial effects corresponding to the execution method.

[0101] Figure 5 A schematic diagram of a photovoltaic inverter system provided in an embodiment of the present application is shown in FIG. Figure 5 The photovoltaic inverter system includes: at least two input circuits, an inverter module and an early warning device provided in any embodiment of the present application, each input circuit includes an input terminal and a boost module connected in series, and the inverter module is connected to each boost module.

[0102] It is understandable that the boost module includes a boost circuit, and the boost circuit can be a unidirectional or bidirectional boost circuit, and the boost circuit can be any boost circuit without limitation. The inverter module includes an inverter circuit, and the inverter circuit can be any inverter circuit without limitation. The early warning device is an early warning device provided in any embodiment of the present application, and is used to execute an early warning method for the DC terminal temperature of an inverter provided in any embodiment of the present application.

[0103] Understandably, Figure 5 Only a case of two input circuits is illustrated. In other embodiments, n input circuits may be included, where n is a positive integer greater than or equal to 2.

[0104] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this application can be executed in parallel, sequentially or in different orders, as long as the expected results of the technical solution of this application can be achieved, and this document is not limited here.

[0105] The above specific implementations do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. An early warning method for inverter DC terminal temperature, characterized in that: include: Collect the current temperature and current of each terminal branch of the inverter; Determining a temperature abnormality alarm mode for each of the terminal branches according to each of the current temperatures, each of the current currents, and a target temperature setting value; According to each of the temperature abnormality alarm modes, the operating state of each of the terminal branches is controlled.

2. The early warning method according to claim 1, characterized in that: The determining of the abnormal temperature alarm mode of each terminal branch according to each current temperature, each current current and the target temperature setting value comprises: Calculate the average value of the current temperatures of all terminal branches and the temperature difference of each terminal branch according to each current temperature and each current current; According to each of the current temperatures, each of the temperature differences, the average value and the target temperature setting value, a temperature abnormality alarm mode of each of the terminal branches is determined.

3. The early warning method according to claim 2, characterized in that: The step of calculating the average current temperature of all terminal branches and the temperature difference of each terminal branch according to each current temperature and each current current comprises: The theoretical temperature under the current current, a first temperature difference between the current temperature and the theoretical temperature, an average value of the current temperatures of all terminal branches, and a second temperature difference between the current temperature of each terminal branch and the average value are calculated.

4. The early warning method according to claim 2, characterized in that: The target temperature setting value includes a first target temperature setting value; Determining the temperature abnormality alarm mode of each terminal branch according to each current temperature, each temperature difference, the average value and the target temperature setting value includes: Determining whether the current temperature is greater than or equal to the first target temperature setting value; If the current temperature is greater than or equal to the first target temperature setting value, it is determined that the temperature abnormality alarm mode of the terminal branch is a fault mode.

5. The early warning method according to claim 3, characterized in that: The target temperature setting value also includes a second target temperature setting value; Determining the temperature abnormality alarm mode of each terminal branch according to each current temperature, each temperature difference, the average value and the target temperature setting value includes: determining whether the first temperature difference is greater than the second target temperature setting value; If the first temperature difference is greater than the second target temperature setting value, it is determined that the temperature abnormality alarm mode of the terminal branch is the first alarm mode.

6. The early warning method according to claim 3, characterized in that: The target temperature setting value also includes a third target temperature setting value; and determining the temperature abnormality alarm mode of each terminal branch according to each of the current temperatures, each of the temperature differences, the average value, and the target temperature setting value includes: determining whether the second temperature difference is greater than the third target temperature setting value; If the second temperature difference is greater than the third target temperature setting value, it is determined that the temperature abnormality alarm mode of the terminal branch is the second alarm mode.

7. The early warning method according to claim 3, characterized in that: Determining the temperature abnormality alarm mode of each terminal branch according to each current temperature, each temperature difference, the average value and the target temperature setting value includes: In the second alarm mode, determining whether the first temperature difference is greater than a second target temperature setting value; If, in the second alarm mode, the first temperature difference is greater than the second target temperature setting value, it is determined that the temperature abnormality alarm mode of the terminal branch is the third alarm mode.

8. The early warning method according to any one of claims 1 to 7, characterized in that: According to each of the abnormal temperature alarm modes, controlling the operating state of each of the terminal branches includes: The inverter is controlled to shut down and each of the terminal branches is closed, or the operating power of the boost module in the terminal branch corresponding to each of the abnormal temperature alarm modes is controlled to remain unchanged or to be closed.

9. An inverter DC terminal temperature early warning device, characterized in that: include: A collection module, which is used to collect the current temperature and current of each terminal branch of the inverter; A determination module, the determination module is used to determine the temperature abnormality alarm mode of each of the terminal branches according to each of the current temperatures, each of the current currents and a target temperature setting value; A control module, the control module is used to control the operating state of each of the terminal branches according to each of the temperature abnormality alarm modes.

10. A photovoltaic inverter system, characterized in that: include: At least two input circuits, the input circuits comprising input terminals and a boost module, the input terminals being connected in series with the boost module; an inverter module, the inverter module being connected to each of the boost modules; and According to the early warning device as claimed in claim 9, the acquisition module of the early warning device is connected to each of the input terminals, and the control module of the early warning device is connected to the boost module and the inverter module.

Images