Power converter

Abstract

The utility model provides a power converter and a method for judging an abnormal terminal of the power converter. The power converter comprises a plurality of DC terminals, a plurality of temperature detection units, a plurality of DC / DC conversion circuits, at least one DC / AC conversion circuit and a controller. The temperature detection unit is used for detecting the temperature of the direct current terminal; when the highest temperature value in the temperatures of the plurality of DC terminals is greater than a first alarm threshold value, the current value of the input current of at least one DC / DC conversion circuit is controlled to be reduced, and if the current value of the input current of the at least one DC / DC conversion circuit is reduced and the highest temperature value is reduced to be less than or equal to a first safety threshold value, the current value of the input current of the at least one DC / DC conversion circuit is controlled to be less than or equal to the first safety threshold value. And outputting a signal indicating that the DC terminal corresponding to the at least one DC / DC conversion circuit is abnormal. According to the power converter, the position of the abnormal terminal can be rapidly detected, the terminal and even the power converter are prevented from being damaged due to the fact that the temperature of the terminal is too high, the detection control logic is simple, and the abnormal terminal can be effectively detected through a low-cost detection unit.

Description

[0001] This application claims priority to a Chinese patent application filed with the State Intellectual Property Office of China on May 17, 2023, with application number 202310558778.3 and application name “A Power Converter and a Method for Determining Abnormal Terminals of a Power Converter”, the entire contents of which are incorporated by reference in this application. Technical Field

[0002] The present application relates to the field of power conversion equipment safety, and in particular to a power converter. Background Art

[0003] As the environment and energy crisis are problems facing the world, new energy sources such as wind power and solar energy have naturally become one of the important ways to improve the energy structure and solve energy problems. Power converters, as an important part of new energy power generation solutions, are rapidly developing in the direction of high efficiency, reliability and low cost.

[0004] Power converters, including inverters and converters, are used for DC / DC conversion, DC / AC conversion, or AC / DC conversion in various scenarios. Power converters can be equipped with different numbers of current DC terminals according to specific application scenarios to receive current input from the previous circuit. During use, the current DC terminals may have poor contact due to loose connection or other reasons, causing the temperature of some terminals to continue to rise. Long-term high-temperature operation may cause the current DC terminals to burn out in some extreme cases. In order to avoid this situation, it is necessary to find the location of the abnormal terminal through temperature detection and other methods, and deal with the abnormal terminal in a timely manner to ensure the continuous and stable operation of the power converter. Utility Model Content

[0005] The present application provides a power converter that can promptly detect the existence of abnormal terminals and find the location of the abnormal terminals, thereby facilitating maintenance personnel to perform maintenance operations on the abnormal terminals of the power converter and ensuring continuous and stable operation of the power converter.

[0006] In a first aspect, the present application provides a power converter, characterized in that it includes multiple DC terminals, multiple temperature detection units, multiple DC / DC (direct current / direct current) conversion circuits, at least one DC / AC (direct current / alternating current) conversion circuit and a controller; the input ends of the multiple DC terminals are connected to a DC source, the output ends of the multiple DC terminals are correspondingly connected to the input ends of the multiple DC / DC conversion circuits, the output ends of the multiple DC / DC conversion circuits are correspondingly connected to the input ends of the at least one DC / AC conversion circuit, and the output end of the at least one DC / AC conversion circuit is used to connect to a load; multiple temperature detection units are used to detect the detected temperatures of the multiple DC terminals; the controller, in response to the highest temperature value among the detected temperatures of the multiple DC terminals being greater than a first alarm threshold, controls the current value of the input current of at least one DC / DC conversion circuit among the multiple DC / DC conversion circuits to decrease, if at the input of the at least one DC / DC conversion circuit After the current value of the current decreases, the maximum temperature value decreases to less than or equal to the first safety threshold, and a signal indicating that the DC terminal corresponding to the at least one DC / DC conversion circuit is abnormal is output, and the first safety threshold is less than or equal to the first alarm threshold; or the controller, in response to the maximum temperature value among the detected temperatures of the multiple DC terminals being greater than the second alarm threshold, controls the current value of the input current of all DC / DC conversion circuits in the multiple DC / DC conversion circuits to decrease, and then in response to the maximum temperature value decreasing to less than or equal to the second safety threshold, controls the current value of the input current of at least one DC / DC conversion circuit in the multiple DC / DC conversion circuits to increase, if after the current value of the input current of the at least one DC / DC conversion circuit increases, the maximum temperature value increases to greater than the second alarm threshold, and a signal indicating that the DC terminal corresponding to the at least one DC / DC conversion circuit is abnormal is output, wherein the second safety threshold is less than or equal to the second alarm threshold.

[0007] In this embodiment, the highest temperature value among the multiple terminals is obtained by detecting the temperature values ​​of the multiple terminals. When the highest temperature value exceeds the alarm threshold, it indicates that the temperature of at least one terminal is abnormal. By controlling the input current corresponding to a certain terminal and observing whether the highest temperature value changes, it can be determined whether the terminal is an abnormal terminal. This method of finding abnormal terminals can use a low-cost temperature detection unit for temperature detection (such as NTC, etc.), effectively saving the use of chips in the power converter and finding abnormal terminals in a timely manner.

[0008] In combination with the first aspect, in a first possible implementation, the power converter includes a fan; in response to a maximum temperature value among the detected temperatures of a plurality of DC terminals being greater than a first alarm threshold, controlling the current value of the input current of at least one DC / DC conversion circuit among the plurality of DC / DC conversion circuits to decrease, including: in response to a maximum temperature value among the detected temperatures of the plurality of DC terminals being greater than the first alarm threshold, controlling the fan speed to increase so that the maximum temperature value is reduced to below the first alarm threshold, then controlling the fan speed to decrease, and then in response to the maximum temperature value being restored to the first alarm threshold, controlling the current value of the input current of at least one DC / DC conversion circuit among the plurality of DC / DC conversion circuits to decrease.

[0009] In this embodiment, the temperature of the abnormal terminal is first reduced by increasing the speed of the fan to reduce the temperature of the abnormal terminal to below the alarm threshold, and then the speed of the fan is reduced to maintain the temperature of the abnormal terminal as close to the alarm threshold as possible. Under this condition, when the input current of the abnormal DC terminal is reduced, the reduction in the maximum temperature value can be shown in a shorter time, thereby reducing the time consumed by the abnormal terminal detection process.

[0010] In combination with the first aspect to any one of the first possible implementations of the first aspect, in a second possible implementation, the power converter includes a fan; in response to the highest temperature value among the detected temperatures of multiple DC terminals being greater than a second alarm threshold, the current value of the input current of all DC / DC conversion circuits in the multiple DC / DC conversion circuits is controlled to be reduced, including: in response to the highest temperature value among the detected temperatures of the multiple DC terminals being greater than the second alarm threshold, the current value of the input current of all DC / DC conversion circuits in the multiple DC / DC conversion circuits is controlled to be reduced, and the fan speed is controlled to be increased.

[0011] Similarly, when all input current values ​​are controlled to decrease, the fan speed can be simultaneously controlled to increase so that the temperature of the abnormal terminal can be quickly reduced, that is, the maximum temperature value can be quickly reduced to below the alarm threshold. This can also reduce the time consumed by the entire abnormal terminal detection process, thereby quickly discovering the location of the abnormal terminal and reducing the occurrence of risks.

[0012] In combination with the second possible implementation of the first aspect, in a third possible implementation, in response to the maximum temperature value dropping to less than or equal to the second safety threshold, the current value of the input current of at least one DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to increase, including: in response to the maximum temperature value dropping to less than or equal to the second safety threshold, the fan speed is controlled to decrease, and then the current value of the input current of at least one DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to increase.

[0013] It should be understood that after the maximum temperature value drops to less than or equal to the second safety threshold, the fan speed is controlled to decrease so as to reduce the heat dissipation in the power cavity, and then the current is increased to execute the abnormal judgment logic so that the rise in abnormal terminal temperature can be observed more quickly. At this time, the fan speed can be increased to restore to the original speed.

[0014] In combination with any one of the first aspect to the third possible implementation manners of the first aspect, in a fourth possible implementation manner, controlling the current value of the input current of at least one DC / DC conversion circuit among multiple DC / DC conversion circuits to decrease includes: sequentially controlling the current value of the input current of the DC / DC conversion circuits among the multiple DC / DC conversion circuits to decrease until the current value of the input current of the nth DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to decrease, and the maximum temperature value is reduced to less than or equal to the first safety threshold.

[0015] In combination with any one of the first aspect to the fourth possible implementation manner of the first aspect, in a fifth possible implementation manner, controlling the current value of the input current of at least one DC / DC conversion circuit among multiple DC / DC conversion circuits to increase includes: sequentially controlling the current value of the input current of the DC / DC conversion circuits among the multiple DC / DC conversion circuits to increase until the current value of the input current of the mth DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to increase, and the maximum temperature value increases to be greater than the second alarm threshold.

[0016] In combination with any one of the first aspect to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, the controller is used to control the current value of the input current of one of the DC / DC conversion circuits to decrease after outputting a signal indicating that there is an abnormality in the DC terminal corresponding to one of the multiple DC / DC conversion circuits.

[0017] In a second aspect, the present application provides a grid power supply system, which includes a power supply and a power converter provided by the above-mentioned first aspect and any possible implementation method of the first aspect, wherein the power supply is used to provide a DC voltage input for the power converter; the power converter is used to perform DC inverter conversion based on the DC voltage provided by the power supply, and output AC voltage to a load.

[0018] In a third aspect, the present application provides a method for judging abnormal terminals of a power converter, which is applied to a power converter, including multiple DC terminals, multiple temperature detection units, multiple DC / DC (direct current / direct current) conversion circuits and at least one DC / AC (direct current / alternating current) conversion circuit; the input ends of the multiple DC terminals are connected to a DC source, the output ends of the multiple DC terminals are correspondingly connected to the input ends of the multiple DC / DC conversion circuits, the output ends of the multiple DC / DC conversion circuits are correspondingly connected to the input ends of the at least one DC / AC conversion circuit, and the output end of the at least one DC / AC conversion circuit is used to connect to a load; multiple temperature detection units are used to detect the detected temperatures of the multiple DC terminals; the method includes: when the highest temperature value among the detected temperatures of the multiple DC terminals is greater than a first alarm threshold, controlling the current value of the input current of at least one DC / DC conversion circuit in the multiple DC / DC conversion circuits to decrease, if in the at least one DC After the current value of the input current of the DC / DC conversion circuit decreases, the maximum temperature value decreases to less than or equal to the first safety threshold, and a signal indicating that the DC terminal corresponding to the at least one DC / DC conversion circuit is abnormal is output, and the first safety threshold is less than or equal to the first alarm threshold; or when the highest temperature value among the detected temperatures of the multiple DC terminals is greater than the second alarm threshold, the current values ​​of the input currents of all the DC / DC conversion circuits in the multiple DC / DC conversion circuits are controlled to decrease, and when the highest temperature value decreases to less than or equal to the second safety threshold, the current value of the input current of at least one DC / DC conversion circuit in the multiple DC / DC conversion circuits is controlled to increase; if after the current value of the input current of the at least one DC / DC conversion circuit increases, the maximum temperature value increases to greater than the second alarm threshold, a signal indicating that the DC terminal corresponding to the at least one DC / DC conversion circuit is abnormal is output, wherein the second safety threshold is less than or equal to the second alarm threshold.

[0019] In combination with the third aspect, in a first possible implementation, the power converter includes a fan; in the method, when the highest temperature value among the detected temperatures of multiple DC terminals is greater than a first alarm threshold, the current value of the input current of at least one DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to decrease, including: when the highest temperature value among the detected temperatures of the multiple DC terminals is greater than the first alarm threshold, the fan speed is controlled to increase so that the highest temperature value is reduced to below the first alarm threshold, and then the fan speed is controlled to decrease. When the highest temperature value returns to the first alarm threshold, the current value of the input current of at least one DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to decrease.

[0020] In combination with the third aspect, in a second possible implementation, the power converter includes a fan; when the highest temperature value among the detected temperatures of multiple DC terminals in the method is greater than a second alarm threshold, the current value of the input current of all DC / DC conversion circuits in the multiple DC / DC conversion circuits is controlled to be reduced, including: when the highest temperature value among the detected temperatures of multiple DC terminals is greater than the second alarm threshold, the current value of the input current of all DC / DC conversion circuits in the multiple DC / DC conversion circuits is controlled to be reduced, and the fan speed is controlled to be increased.

[0021] In combination with the first possible implementation of the third aspect, in a third possible implementation, when the maximum temperature value in the method is reduced to less than or equal to the second safety threshold, the current value of the input current of at least one DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to increase, including: when the maximum temperature value is reduced to less than or equal to the second safety threshold, the fan speed is controlled to decrease, and then the current value of the input current of at least one DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to increase.

[0022] In combination with the third aspect to the third possible implementation manner of the third aspect, in a fourth possible implementation manner, the method controls the current value of the input current of at least one DC / DC conversion circuit among multiple DC / DC conversion circuits to decrease, including: sequentially controlling the current value of the input current of the DC / DC conversion circuits among the multiple DC / DC conversion circuits to decrease, until the current value of the input current of the nth DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to decrease, and the maximum temperature value is reduced to less than or equal to the first safety threshold.

[0023] In combination with the third aspect to the fourth possible implementation manner of the third aspect, in a fifth possible implementation manner, the method controls the current value of the input current of at least one DC / DC conversion circuit among multiple DC / DC conversion circuits to increase, including: sequentially controlling the current value of the input current of the DC / DC conversion circuits among the multiple DC / DC conversion circuits to increase, until the current value of the input current of the mth DC / DC conversion circuit among the multiple DC / DC conversion circuits is controlled to increase, and the maximum temperature value increases to be greater than the second alarm threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of an application scenario of a power converter provided in an embodiment of the present application;

[0025] Figure 2 is a schematic diagram of the structure of a power converter provided in an embodiment of the present application;

[0026] Figure 3 is a schematic diagram of the structure of a power converter provided in an embodiment of the present application;

[0027] Figure 4 is a schematic diagram of the structure of a power converter provided in an embodiment of the present application;

[0028] Figure 5 is a schematic top view of a power converter provided in an embodiment of the present application;

[0029] Figure 6 is a front view schematic diagram of a power converter provided in an embodiment of the present application;

[0030] Figure 7 is a schematic diagram of a power grid power supply system provided in an embodiment of the present application;

[0031] Figure 8 This is a schematic diagram of a terminal abnormality judgment process of a power converter provided by an embodiment of the present application;

[0032] Fig. 9 This is a schematic diagram of a terminal abnormality judgment process of a power converter provided by an embodiment of the present application;

[0033] Fig.10 This is a schematic diagram of a terminal abnormality judgment process of a power converter provided by an embodiment of the present application;

[0034] Fig.11 This is a schematic diagram of a terminal abnormality judgment process of a power converter provided by an embodiment of the present application; Fig.12 It is a schematic diagram of a terminal abnormality detection circuit of a power converter provided in an embodiment of the present application; Fig.13 It is a schematic diagram of a terminal abnormality detection circuit of a power converter provided in an embodiment of the present application; Fig.14 It is a schematic diagram of a terminal abnormality detection circuit of a power converter provided in an embodiment of the present application; Fig.15 It is a schematic diagram of the circuit structure of a power converter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The photovoltaic inverter and photovoltaic system provided in this application can be applied to various application fields such as the field of new energy power generation, the field of peak and frequency regulation of traditional power generation, and the field of power supply for important equipment. The specific application can be determined according to the actual application scenario and is not limited here. The photovoltaic inverter and photovoltaic system provided in this application can be applied to different scenarios such as large-scale photovoltaic power stations, industrial and commercial photovoltaic power generation, and household photovoltaic power generation. It is not limited here. The following will take the application scenario of controlling the inverter in a photovoltaic power supply environment as an example for explanation, and will not be repeated below.

[0036] The technical solution provided in the embodiment of the present application can quickly respond to abnormal conditions of the DC terminals of the power converter current, and quickly find the location of the abnormal terminal, so that maintenance personnel can perform subsequent maintenance operations on the abnormal terminal. It should be understood that the power converter of the present application includes inverters, converters, etc., which are used for power converters for DC / DC conversion, DC / AC conversion, or AC / DC conversion in various scenarios. For the convenience of explanation, the embodiment of the present application will take the photovoltaic inverter application scenario as an example to introduce the technical solution of the present application, and will not be repeated below.

[0037] For ease of understanding, the terms involved in the embodiments of the present application are first explained.

[0038] PV: Solar photovoltaic panels;

[0039] DC terminal: The terminal on the photovoltaic inverter used to receive the DC input of the PV or the DC input of the energy storage device;

[0040] NTC: Negative temperature coefficient thermistor;

[0041] Connection: should be understood in a broad sense. For example, A and B are connected, which can be either direct or indirect through an intermediary.

[0042] The specific implementation of the present application will be clearly described below in conjunction with the accompanying drawings.

[0043] The application scenario is pure photovoltaic power generation directly connected to the grid, such as Figure 1 As shown, the power supply of the power converter 100 is PV, which can convert solar energy into electrical energy and output direct current to the power converter 100. The power converter 100 performs corresponding power conversion based on the direct current provided by PV, which generally includes DC / DC conversion and DC / AC conversion, to convert the input direct current into alternating current and output it to the load, wherein the load can be a power grid or a household electrical appliance, etc.

[0044] It should be understood that in actual applications, before the DC power output by the PV is input into the power converter, it may also pass through a DC / DC unit so that the voltage and frequency of the DC power received by the power converter 100 are within its adaptation range. Since the setting of the DC / DC is not directly related to the technical solution provided in the present application, it will not be described in detail in the embodiments of the present application.

[0045] In a power converter provided in an embodiment of the present application, please refer to the attached specification. Figure 2The power converter 100 has a plurality of DC terminals 101, which can be used to receive DC power input from a DC source such as PV. Each DC terminal 101 has a corresponding DC / DC conversion circuit 110. The DC / DC conversion circuit 110 can convert the DC power input from the DC terminal 101 into a DC voltage, and then input the DC power after the DC voltage conversion to the DC / AC conversion circuit 120. The DC / AC conversion circuit 120 can convert the DC power received from the DC / DC conversion circuit 110 into the AC power required by the external load, thereby realizing the power supply of the entire power supply system to the load. Since the DC terminal 101 is generally mechanically connected by manually bringing the wire from the PV side, the terminal may become loose due to errors in manual installation, accidental collision, etc. The loose DC terminal 101 accompanied by the input of large current may cause the temperature of the DC terminal 101 to rise and then cause damage to the DC terminal 101 or even the entire power converter 100. Therefore, it is necessary to configure a temperature detection unit 102 to perform temperature detection on the DC terminal 101 of the power converter 110. When there is an abnormality in the DC terminal 101, the temperature of the DC terminal 101 can be reduced by timely adjusting the current value of the input current of the DC / DC conversion circuit 110.

[0046] In the embodiment provided in the present application, multiple temperature detection units 102 can adopt low-cost NTC (such as surface-mount NTC), and NTC can perform temperature detection on the corresponding DC terminal 101 to obtain multiple temperature data. Since NTC can only transmit temperature data but cannot transmit which specific DC terminal 101 the temperature data corresponds to, the highest temperature value among the multiple temperature data can be used to determine whether there is an abnormality in the multiple DC terminals 101 in the power converter 100, and then each DC terminal 101 can be gradually screened. The highest temperature value can be achieved through a competition circuit. Since the competition circuit is a common means used by technicians in this field to obtain the maximum value of data in a data group, it will not be introduced in detail here.

[0047] In a possible implementation, a first alarm threshold may be preset, and the first alarm threshold may be obtained by performing relevant safety tests on the power converter 100. When the highest temperature value among the multiple temperature data exceeds the first alarm threshold, it indicates that there is an abnormal DC terminal among the multiple DC terminals 101, and the abnormal terminal may have a problem of not being firmly plugged in during manual plugging, or may have a problem of being loose due to collision with foreign objects or long-term use, or may have an abnormal temperature due to electrical aging of the terminal.

[0048] It is understandable that if the maximum temperature value exceeds the first alarm threshold, the input current of the DC / DC conversion circuit 110 corresponding to the normal DC terminal 101 is reduced, although the temperature value of the DC terminal 101 may be reduced, since the temperature of the normal DC terminal 101 is not the maximum temperature value, the maximum temperature value in the temperature data presented by the multiple temperature detection units 102 will not change. Similarly, if the maximum temperature value exceeds the first alarm threshold, the current value of the input current of the DC / DC conversion circuit 110 corresponding to one or several DC terminals 101 is reduced, and the maximum temperature value is reduced to a certain extent, it can be determined that the one or several DC terminals 101 are abnormal terminals. It can be further understood that if the maximum temperature value does not change after the current values ​​of the input currents of multiple DC / DC conversion circuits 110 are reduced, it means that the DC terminals 101 corresponding to these DC / DC conversion circuits 110 are not abnormal; on the contrary, if the maximum temperature value decreases after the current values ​​of the input currents of multiple DC / DC conversion circuits 110 are reduced, it means that the range of abnormal terminals is within the range of the DC terminals 101 corresponding to these DC / DC conversion circuits 110. It should be noted that the degree of reduction of the maximum temperature value here can be reduced to less than or equal to the first safety threshold, and it can be considered that the DC terminal 101 corresponding to the DC / DC conversion circuit 110 whose current value of the input current is reduced is abnormal.

[0049] It is understandable that it takes a certain amount of time for the temperature of the DC terminal 101 to drop, so it takes some time to observe. If the corresponding DC terminal 101 is the only abnormal terminal, the maximum temperature value will drop after the observation time is long enough, so that the abnormality of the terminal can be determined. However, if the observation time is too short, the temperature of the terminal may not have dropped completely, which may cause a certain probability of misjudgment. However, in order to make an accurate judgment, an observation time that is too long cannot be set. If the observation time is too long, when the terminal is a non-abnormal terminal, too much time will be wasted, making the pace of screening for abnormal terminals very slow, and wasting time on troubleshooting terminal abnormalities. Therefore, according to the safety protection requirements of the use scenario of the power converter 100, a first time threshold can be set based on comprehensive experimental data to serve as the observation time of the maximum temperature value after the current value of the input current is reduced. If within the first time threshold, the maximum temperature value is reduced to less than or equal to the first safety threshold, it is considered that the DC terminal 101 corresponding to the DC / DC conversion circuit 110 that has reduced the current value of the input current is an abnormal terminal. If after the first time threshold, the maximum temperature value has not dropped to less than or equal to the first safety threshold, the DC terminal 101 corresponding to the DC / DC conversion circuit 110 is likely not an abnormal terminal. The abnormal terminal judgment process can be stopped, and the abnormal detection judgment logic can be executed on the DC terminals 101 corresponding to other DC / DC conversion circuits 110. The first safety threshold here can also be set in advance through corresponding safety experimental test data. It can be understood that the value will be different depending on the specific structure and usage environment of different power converters. The embodiment of the present application is not specifically limited here. Among them, the first safety threshold can be less than or equal to the first alarm threshold.

[0050] In another possible implementation, when the highest temperature value among the temperature data of multiple DC terminals 101 detected by the NTC exceeds a certain value, the current value of the input current of all DC / DC conversion circuits 110 can be reduced first, so that the current borne by all DC terminals 101 can be reduced first, so that the temperature of abnormal or non-abnormal terminals can be reduced accordingly, and the equipment safety of the power converter 100 can be ensured as soon as possible. The certain value here can be the second alarm threshold. It can be understood that after the current value of the input current of all DC / DC conversion circuits 110 is reduced for a period of time, the highest temperature value will gradually decrease. After it is reduced to a certain value, it can be considered that the temperature of all DC terminals 101 is in a safe state. Here, a value can be set as the second safety threshold, that is, if the highest temperature value is reduced to less than or equal to the second safety threshold, the temperature of all DC terminals 101 is in a safe state. If at this time, the maximum temperature value rises to be greater than the second alarm threshold within the second time threshold after the current value of the input current of a certain DC / DC conversion circuit 110 increases, it indicates that the DC terminal 101 corresponding to the DC / DC conversion circuit 110 is abnormal, wherein the second safety threshold may be less than or equal to the second alarm threshold.

[0051] It should be noted that, in the above-mentioned two implementations, due to different strategies for finding abnormal terminals, the timing and method of reducing the input current are also different, and the duration of the maximum temperature value being at a high level may also be different. Therefore, the first safety threshold and the second safety threshold, the first alarm threshold and the second alarm threshold, and the first time threshold and the second time threshold may also adopt different values. The setting of specific values ​​can also be determined by corresponding safety regulations and experimental test results, and the embodiments of the present application do not impose specific restrictions.

[0052] It should be understood that the DC / DC conversion circuit 110 in the power converter 100 may correspond to a temperature detection unit 102 and a DC terminal 101, as shown in the appendix of the specification. Figure 2 In the specific design of the power converter, there may be a situation where two DC input terminals 101 correspond to one DC / DC conversion circuit 110. At this time, the current value of the input current of the DC / DC conversion circuit 110 is controlled to be reduced, and the input current borne by the two DC terminals 101 will be adjusted at the same time, that is, the temperature values ​​of the two DC terminals 101 will be adjusted at the same time. At this time, the temperature detection unit 102 can be directly placed between the two DC terminals 101 corresponding to the same DC / DC conversion circuit 110, and the temperature values ​​of the two DC terminals 101 can be detected at the same time (of course, one DC terminal 101 can correspond to one temperature detection unit 102, and the embodiment of the present application does not make specific restrictions). This design can refer to the attached drawings of the specification. Figure 3. In this case, the above two implementation methods are used to check for abnormal terminals, and the final result of the check is two DC terminals 101 that may have abnormalities, wherein at least one of the two DC terminals 101 is abnormal. Similarly, the DC / DC conversion circuit 110 can also correspond to the input of three or more DC terminals 101. For example, the DC / DC conversion circuit corresponds to 5 DC inputs of the DC source, each DC input has 2 positive and negative terminals, and 10 DC terminals need to be connected for DC input. The number and position settings of the temperature detection unit 102 can also be flexibly adjusted. The principle of abnormal terminal checking is similar, but the granularity of the check is different. The embodiment of the present application does not impose specific restrictions.

[0053] Reference Manual Attachments Figure 4 In a power converter 100 provided in an embodiment of the present application, a fan 130 may be included, and the number of the fan 130 may be one or more, and the embodiment of the present application does not make specific restrictions. The fan 130 can dissipate heat for the power device inside the power converter 100 during the normal operation of the power converter 100. When the highest temperature value in the temperature data detected by the NTC exceeds the first alarm threshold or the second alarm threshold, the fan 130 can also be coordinated and controlled to increase or reduce the speed, adjust the heat dissipation speed inside the power converter 100, and then adjust the temperature change speed of the DC terminal 101. The fan 130 can be a forced convection between the air in the power converter 100 and the external air, so that the temperature in the power converter 100 can be reduced more quickly, and then drive other parts of the power converter 100 to reduce the temperature accordingly. It should be understood that the rotation of the fan 130 will consume a certain amount of electric energy. Therefore, the speed of the fan 130 can be flexibly changed according to factors such as the temperature of the power converter 100, weather conditions, and ambient temperature, so that the fan 130 can achieve the best possible heat dissipation effect under the most economical conditions. Correspondingly, the maximum temperature value can also be used as a reference factor for setting the speed of the fan 130. When the controller learns that the maximum temperature threshold reaches the alarm threshold, it can control the speed of the fan 130 to change so that the maximum temperature value changes to within the desired range, and then analyze the change in the maximum temperature value by adjusting the current value of the input current, and then output the abnormal terminal judgment result.

[0054] In a possible implementation, when the maximum temperature value exceeds the first alarm threshold, the speed of the fan 130 can be controlled to increase so that the maximum temperature value can be reduced to below the first alarm threshold. In this way, the maximum temperature value of the DC terminal 101 can be reduced to below the first alarm threshold before executing the subsequent abnormal terminal detection strategy.

[0055] Furthermore, after the maximum temperature value is reduced to below the first alarm threshold, the speed of the fan 130 can be reduced again, so that the maximum temperature threshold is increased to the first alarm threshold, and when the maximum temperature value is increased to the first alarm threshold again, the current value change of the input current of the DC / DC conversion circuit is controlled. If the maximum temperature value is reduced to less than or equal to the first safety threshold within the first time threshold after the current value of the input current of the DC / DC conversion circuit is reduced, it means that the DC terminal 101 corresponding to the DC / DC conversion circuit is abnormal. With such an implementation, the heat dissipation capacity of the fan 130 and the heat generation of the abnormal terminal can be maintained in an almost balanced state, that is, the temperature of the abnormal terminal is maintained at the first alarm threshold as much as possible, so that when the current value of the input current of the subsequent DC / DC conversion circuit 110 is reduced, if the input current corresponds to an abnormal terminal, the reduction of the maximum temperature value can be observed more quickly, which can save time for judging the abnormal terminal and improve the efficiency of abnormal terminal screening. Therefore, in actual application, a second time threshold can be set in the same way as the first time threshold is set in the aforementioned embodiment. The second time threshold can be smaller than the first time threshold because when the heat dissipation capacity of the fan 130 and the heat generation of the DC terminal 101 maintain a relatively balanced state, the abnormal terminal responds to the decrease in the current value of the input current of the DC / DC conversion circuit 110 and the speed at which it decreases will generally be faster. Of course, this requires comprehensive consideration of the use environment of the power converter 100 and the specific design and experimental testing in terms of power and structure to set the second time threshold, and the embodiments of the present application do not impose any restrictions on this.

[0056] In another possible implementation, when the maximum temperature value is greater than the second alarm threshold, the current value of the input current of all DC / DC conversion circuits 110 can be reduced, and at the same time, the speed of the fan 130 can be controlled to increase so that the maximum temperature value can be reduced more quickly to less than or equal to the second safety threshold. In this way, the temperature of all DC terminals 101 can be reduced, and because of the assistance of the speed increase of the fan 130, the temperature of the DC terminal 101 will drop faster, so that all DC terminals 101 can enter a safer state more quickly, so as to better ensure the safety of the DC terminal 101 and the entire power converter 100.

[0057] Furthermore, after the maximum temperature value drops to less than or equal to the second safety threshold, the rotation speed of the fan 130 can be further reduced to reduce the power consumption of the fan 130. At this time, all DC terminals 101 are in a safe state with a lower temperature. At this time, the current value of the input current of any one of the DC / DC conversion circuits 110 in all the DC / DC conversion circuits 110 is controlled to increase. After the current value of the input current of the DC / DC conversion circuit 110 increases, within the second time threshold, the maximum temperature value increases to be greater than the second alarm threshold, indicating that there is an abnormality in the DC terminal 101 corresponding to the DC / DC conversion circuit 110.

[0058] Specifically, when the current value of the input current of at least one DC / DC conversion circuit 110 is controlled to be reduced after the highest temperature value among the temperatures of the multiple DC terminals 101 is greater than the first alarm threshold, the current values ​​of the input currents of the DC / DC conversion circuits 110 in the multiple DC / DC conversion circuits 110 can be reduced in sequence (similarly, before this, the speed of the fan 130 can be increased first, the highest temperature value can be reduced to below the first alarm threshold, and then the speed of the fan 130 can be reduced to restore the highest temperature value to the first alarm threshold. At this time, the heat dissipation capacity of the fan 130 and the heat generation of the DC terminal 101 are in a nearly balanced state). For example, the power converter 100 has a total of multiple DC / DC conversion circuits 110, then the current value of the input current of the first DC / DC conversion circuit 110 is first reduced. If the maximum temperature value does not change within the first time threshold after the current value of the input current of the first DC / DC conversion circuit 110 is reduced, the current value of the input current of the second DC / DC conversion circuit 110 continues to be reduced until the maximum temperature value within the first time threshold is reduced to less than or equal to the first safety threshold after the current value of the input current of the nth DC / DC conversion circuit 110 is reduced, which indicates that there is an abnormality in the DC terminal 101 corresponding to the nth DC / DC conversion circuit. Among them, since during the period of reducing the current values ​​of the input currents of the two DC / DC conversion circuits, time is required to observe the highest temperature value after the previous current value is reduced, the time interval between the two current value reductions needs to be greater than or equal to the preset first time threshold, that is, the time interval between reducing the current value of the input current of the qth DC / DC conversion circuit 110 and reducing the current value of the input current of the q+1th DC / DC conversion circuit 110 is greater than or equal to the first time threshold, wherein 1≤q≤n-1, and is an integer.

[0059] In another possible specific embodiment, when the current value of the input current of at least one DC / DC conversion circuit 110 is controlled to be reduced after the highest temperature value among the temperatures of multiple DC terminals 101 is greater than the second alarm threshold, the current values ​​of the input currents of all DC / DC conversion circuits 110 in the power converter 100 can be reduced to reduce the highest temperature value to less than or equal to the second safety threshold (this process can also be performed as in the aforementioned embodiment, and the rotation speed of the fan 130 can be simultaneously increased to achieve a rapid reduction in the highest temperature value. Similarly, the rotation speed of the fan 130 can also be reduced to reduce power consumption afterwards), and then the current values ​​of the input currents of multiple DC / DC conversion circuits 110 are increased in sequence until the highest temperature value increases to be greater than the second alarm threshold within the second time threshold after the current value of the input current of a certain DC / DC conversion circuit 110 is increased, indicating that there is an abnormality in the DC terminal 101 corresponding to the DC / DC conversion circuit 110. For example, the power converter 100 has a total of multiple DC / DC conversion circuits 110, and the current value of the input current of the first DC / DC conversion circuit 110 is first increased. If the maximum temperature value does not change within the second time threshold after the current value of the input current of the first DC / DC conversion circuit 110 is increased, the current value of the input current of the second DC / DC conversion circuit 110 continues to be increased until the maximum temperature value within the second time threshold is reduced to less than or equal to the second safety threshold after the current value of the input current of the mth DC / DC conversion circuit 110 is increased, indicating that there is an abnormality in the DC terminal 101 corresponding to the mth DC / DC conversion circuit. Among them, since during the period of increasing the current values ​​of the input currents of the two DC / DC conversion circuits 110, time is required to observe the highest temperature value after the previous current value is increased, the time interval between the two increases in current value needs to be greater than or equal to the preset second time threshold, that is, the time interval between increasing the current value of the input current of the p-th DC / DC conversion circuit 110 and increasing the current value of the input current of the p+1-th DC / DC conversion circuit 110 is greater than or equal to the second time threshold, wherein 1≤p≤n-1, and is an integer.

[0060] Furthermore, after determining the position of the abnormal terminal through the above embodiment, the current value of the input current of the DC / DC conversion circuit 110 corresponding to the abnormal terminal can be controlled to decrease or further decrease or even decrease to 0 to protect the safety of the DC terminal 101 and the power converter 100.

[0061] It should be noted that the above-mentioned judgment logic of the power converter 100 needs to be completed by a controller. Figure 5 and Figure 6As shown, it is a schematic top view and a schematic front view of a power converter 100 in the embodiment provided by the present application. Each DC terminal 101 is at the bottom of the power converter 100, and is used to connect the DC cable led from the DC source; several fans 130 are also arranged in sections at positions adjacent to the DC terminal 101, which are used to blow air into the cavity of the power converter 100 to form convection and achieve heat dissipation; the DC terminal 101 also has a corresponding cable inside the power converter 100 to connect the terminal with the corresponding terminal 101' on the PCB (Printed Circuit Board), and the circuit inside the PCB can connect the corresponding connection point 101' of the DC terminal 101 on the PCB to the input end of the DC / DC conversion circuit 110, and can also connect the DC / DC conversion circuit to the DC / AC conversion circuit, and the working state of the DC / DC conversion circuit 110 and the DC / AC conversion circuit 120 is controlled by the controller 140 that is connected to them in communication. The abnormal terminal judgment logic in the aforementioned embodiments can be controlled and implemented by the controller 140. After screening out the corresponding positions of the abnormal terminals, the controller 140 can send a signal to the outside indicating that a DC terminal 101 corresponding to a certain DC / DC conversion circuit 110 has an abnormality.

[0062] It should be noted that the number, position, and connection relationship of units and devices such as the DC / DC conversion circuit 110, DC / AC conversion circuit 120, fan 130, and DC terminal 101 in the power conversion circuit 100 described in the drawings and embodiments of the present application specification are only possible examples and are not limitations on the structure of the power converter 100 in the present application.

[0063] The present application also provides a power grid power supply system. The architecture of the power grid power supply system can refer to Figure 7 The power grid power supply system includes a power supply (such as PV, etc.) and any one of the power converters 100 in the aforementioned embodiments; the power supply can provide a DC voltage input for the power converter 100; the power converter 100 is used to perform DC inverter conversion based on the DC voltage provided by the power supply, and output AC voltage to the load.

[0064] Based on the same inventive concept, the embodiment of the present application also provides a method for determining abnormal terminals of a power converter, which is applied to a power converter, wherein the power converter (which may be as shown in the accompanying drawings of the specification) Figure 2 or attached to the instruction manual Figure 3The power converter 100 shown in the figure includes multiple DC terminals 101, multiple temperature detection units 102, multiple DC / DC (direct current / direct current) conversion circuits 110 and at least one DC / AC (direct current / alternating current) conversion circuit 120; the input ends of the multiple DC terminals 101 are connected to the DC source, the output ends of the multiple DC terminals 101 are correspondingly connected to the input ends of the multiple DC / DC conversion circuits 110, the output ends of the multiple DC / DC conversion circuits 110 are correspondingly connected to the input ends of a DC / AC conversion circuit 120 (there may also be two or more, which is not specifically limited in the embodiment of the present application), and the output end of the DC / AC conversion circuit 120 is used to connect to the load; the temperature detection unit 102 is used to detect the temperature of the DC terminal 101;

[0065] In a possible implementation manner provided in the embodiments of the present application, the method includes:

[0066] When the highest temperature value among the temperatures of the plurality of DC terminals 101 is greater than the first alarm threshold, step S101 is executed;

[0067] Step S101: controlling the current value of the input current of at least one DC / DC conversion circuit among a plurality of DC / DC conversion circuits to decrease;

[0068] If, after the current value of the input current of the at least one DC / DC conversion circuit decreases, the maximum temperature value decreases to be less than or equal to the first safety threshold; executing step S102;

[0069] Step S102: outputting a signal indicating that an abnormality exists in a DC terminal corresponding to the at least one DC / DC conversion circuit.

[0070] Among them, the first safety threshold is less than or equal to the first alarm threshold.

[0071] The execution process of the method in the above embodiment can refer to the accompanying drawings of the reference specification. Figure 7 .

[0072] In another possible implementation manner provided in the embodiments of the present application, the method includes:

[0073] When the maximum temperature value is greater than the first alarm threshold, executing step S201;

[0074] Step S201: sequentially controlling the current values ​​of the input currents of the DC / DC conversion circuits in the plurality of DC / DC conversion circuits to decrease;

[0075] If the maximum temperature value decreases to be less than or equal to the first safety threshold after the current value of the input current of the nth DC / DC conversion circuit is reduced, step S202 is executed;

[0076] Step S202: outputting a signal indicating that an abnormality exists in a DC terminal corresponding to the nth DC / DC conversion circuit.

[0077] It should be noted that after outputting a signal indicating that there is an abnormality in the DC terminal corresponding to the nth DC / DC conversion circuit, the abnormal terminal detection logic can continue to be executed on other DC terminals, or it can be stopped, and the embodiment of the present application does not impose specific limitations.

[0078] The execution process of the method in the above embodiment can refer to the accompanying drawings of the reference specification. Figure 8 .

[0079] In another possible implementation manner provided in the embodiments of the present application, the method includes:

[0080] When the maximum temperature value is greater than the second alarm threshold, execute step S301;

[0081] Step S301: controlling the current values ​​of the input currents of all DC / DC conversion circuits among a plurality of DC / DC conversion circuits to decrease;

[0082] After the maximum temperature value drops to less than or equal to the second safety threshold, step S302 is executed;

[0083] Step S302: controlling the current value of the input current of at least one DC / DC conversion circuit among the plurality of DC / DC conversion circuits to increase;

[0084] If, after the current value of the input current of the at least one DC / DC conversion circuit increases, the maximum temperature value increases to be greater than the second alarm threshold, executing step S303;

[0085] Step S303: outputting a signal indicating that an abnormality exists in a DC terminal corresponding to the at least one DC / DC conversion circuit.

[0086] Among them, the second safety threshold is less than or equal to the second alarm threshold.

[0087] The execution process of the method in the above embodiment can refer to the accompanying drawings of the reference specification. Fig. 9 .

[0088] In another possible implementation manner provided in the embodiments of the present application, the method includes:

[0089] When the maximum temperature value is greater than the second alarm threshold, execute step S401;

[0090] Step S401: controlling the current values ​​of the input currents of all the DC / DC conversion circuits in the plurality of DC / DC conversion circuits to decrease, and after the maximum temperature value decreases to be less than or equal to the second safety threshold, executing step S402;

[0091] Step S402: sequentially controlling the input current values ​​of multiple DC / DC conversion circuits to increase;

[0092] If the maximum temperature value increases to be greater than the second alarm threshold within the second time threshold after the current value of the input current of the mth DC / DC conversion circuit increases, step S403 is executed;

[0093] Step S403: outputting a signal indicating that an abnormality exists in the DC terminal corresponding to the mth DC / DC conversion circuit.

[0094] It should be noted that after outputting a signal indicating that there is an abnormality in the DC terminal corresponding to the mth DC / DC conversion circuit, the abnormal terminal detection logic may continue to be executed or may be stopped, and the embodiment of the present application does not impose any specific limitation thereto.

[0095] The execution process of the method in the above embodiment can refer to the accompanying drawings of the reference specification. Fig.10 .

[0096] It should be understood that the aforementioned abnormal terminal detection method can refer to the controller 140 in the power converter 100 provided in the application to execute the judgment logic. For example, between executing step S101 and step S102, a first time threshold condition can be set. If within the first time threshold after the current value of the input current of the at least one DC / DC conversion circuit is reduced, the maximum temperature value is reduced to less than or equal to the first safety threshold, and then the judgment logic of S102 is executed, if the first time threshold condition is not met, the abnormal judgment process of the DC terminal corresponding to the DC / DC conversion circuit can be stopped, and the DC terminal corresponding to another DC / DC conversion circuit can be selected for abnormal judgment.

[0097] Further, when executing S201, the time interval for the current value of the input current of the two DC / DC conversion circuits to decrease can be controlled to be greater than or equal to the first time threshold, so as to reserve enough time for the abnormal judgment logic. For example, the time interval for the current value of the input current of the qth DC / DC conversion circuit to decrease and the time interval for the current value of the input current of the q+1th DC / DC conversion circuit to decrease is greater than or equal to the first time threshold, where 1≤q≤n-1 and is an integer.

[0098] Accordingly, executing steps S301 to S303 or executing steps S401 to S403 can also be done in the same way as executing steps S101 to S102 and executing steps S201 and S202, with reference to the judgment logic executed by the controller 140 in the power converter 100 provided in the present application. The logic and principles are basically the same and will not be repeated here.

[0099] It should be noted that the power converter also includes a fan, including but not limited to the fan in the previous embodiment as shown in the accompanying drawings of the specification. Figure 4-Figure 6 The power converter 100 shown, the detection method of the abnormal terminal in the above embodiment can also be carried out in conjunction with the speed control of the fan to achieve the effect of more quickly detecting the abnormal terminal. The detailed method flow is similar to the specific control logic of the controller of the power converter 100 in the above embodiment of the present application, and will not be repeated here.

[0100] Combined with reference Figure 6 and Fig.12 , which is a method for detecting the temperature of a DC terminal 101 provided in an embodiment of the present application. On the PCB inside the inverter 100, multiple temperature detection units, multiple DC / DC conversion circuits and at least one DC / AC conversion circuit are integrated, and the output ends 101' of the multiple DC terminals 101 of the inverter 100 are connected to the DC / DC conversion circuit through the PCB, thereby realizing the input of external DC source power.

[0101] like Figure 6 One end of the DC terminal 101 is on the housing of the inverter 100, the output end 101' of the DC terminal 101 is plugged into the PCB, and the temperature detection unit is composed of a plurality of temperature detection branches and an operational amplifier circuit. Each temperature detection branch includes a temperature sensing element 102, which is used to detect the temperature of the output end 101' of the DC terminal 101, thereby realizing the detection of the temperature of the DC terminal 101. The temperature sensing element 102 can be an element such as an NTC, a thermocouple sensor, etc., which can change its own electrical properties with temperature changes. One end of the temperature sensing element 102 on each temperature detection branch is connected to its corresponding DC source, and the other end of the temperature sensing element 102 is connected to the input end of the operational amplifier circuit, and the output end of the operational amplifier circuit is connected to the input end of the controller. When the temperature of the DC terminal 101 changes, the temperature of the output end 101' of the DC terminal 101 changes, the temperature of the temperature sensing element 102 also changes, and the electrical performance of the temperature sensing element 102 also changes, so that the electrical signal received by the operational amplifier circuit changes, and then the electrical signal received by the controller changes, and finally the controller identifies the temperature of the DC terminal 101.

[0102] In one embodiment, continue to refer to Figure 6 One end of the DC terminal 101 is on the housing of the inverter 100, the output end 101' of the DC terminal 101 is plugged into the PCB, the temperature sensing element 102 is an NTC, and the NTC 102 is placed near the output end 101' of the DC terminal 101 to detect the temperature of the output end 101' of the DC terminal 101, and the temperature is approximately the temperature of the DC terminal 101, and based on the temperature, it is determined whether the temperature of the DC terminal 101 is abnormal.

[0103] It should be understood that the higher the rated power of the inverter 100, the more DC input the inverter 100 will require, the more DC terminals 101 will be, and the more NTCs 102 will be required to detect the temperature of the DC terminals 101. For example, in more sophisticated detection requirements, each DC terminal 101 needs to have an NTC 102 to detect its temperature. Fig.12 As shown, an NTC 102 is placed near each DC terminal 101 .

[0104] The specific principle of NTC102 detecting temperature is that the resistance of NTC102 will decrease as the temperature rises. When the potential at one end of NTC102 is fixed, by detecting the potential at the other end of NTC102, it is possible to know whether the resistance of NTC102 has changed, and also whether the temperature of NTC102 has changed. If the temperature of NTC102 is close to the output end 101' of the DC terminal 101, the temperature of NTC102 can be approximated to the temperature of the output end 101' of the DC terminal 101.

[0105] Continue to refer Fig.12 One end of each NTC102 is connected to a DC source VCC, and the other end is grounded through a voltage divider resistor. The connection point between the NTC102 and the voltage divider resistor is connected to the positive end of a diode, and the negative end of the diode is connected to the positive end of the operational amplifier circuit. For example, if the voltage of the DC source VCC is 5V, the resistance of the voltage-dividing resistor is fixed, and the temperature of the DC terminal 101 is normal, the resistance of NTC102 is equal to the resistance of the voltage-dividing resistor, and the potential of the connection point between NTC102 and the voltage-dividing resistor is 2.5V; when the DC terminal 101 is loosely connected, the temperature of the DC terminal 101 will increase, the temperature of NTC102 will increase, the resistance of NTC102 will decrease, and the potential of the connection point between NTC102 and the voltage-dividing resistor will increase. At this time, the operational amplifier circuit will sense the increase in the potential of the connection point between NTC102 and the voltage-dividing resistor, and the operational amplifier circuit will transmit the information to the controller MCU. When the potential value rises to the preset threshold value set in advance inside the controller MCU, it means that the detection temperature of the DC terminal 101 of this path has reached the first alarm threshold value, and the controller MCU will determine that the DC terminal 101 detected by the NTC102 connected to this operational discharge circuit is abnormal.

[0106] Continue to refer Fig.12In one embodiment, an operational amplifier circuit needs to receive electrical signals transmitted by two NTCs 102, that is, two temperature detection branches are combined and connected to the positive terminal of the operational amplifier circuit. Specifically, two DC sources VCC are respectively connected to one end of the NTC 102 near the output end 101' of the two DC terminals 101, and the other ends of the two NTCs 102 are respectively grounded through their corresponding voltage-dividing resistors. The connection points of the two NTCs 102 and the two voltage-dividing resistors are respectively connected to the anodes of the two diodes, and the cathodes of the two diodes are connected to the positive terminal of the operational amplifier circuit. Since the diode can only be turned on when the positive terminal potential is high and the negative terminal potential is low, the one with the higher potential after the two temperature detection branches transmits an electrical signal to the operational amplifier circuit, that is, the one with a higher temperature of the DC terminal 101 will transmit an electrical signal to the operational amplifier circuit. With this design, a little bit of detection accuracy will be sacrificed, but the use of operational amplifier circuits can be reduced, saving hardware costs.

[0107] refer to Fig.13 When the temperature detection accuracy does not need to be so high, multiple temperature detection branches can be combined and connected to an operational amplifier circuit. As long as one of the temperatures of the multiple DC terminals 101 is too high, the controller MCU will determine that there is an abnormality in the DC terminal 101 detected by the NTC102 connected to this operational discharge circuit.

[0108] refer to Fig.14 In another embodiment, one NTC 102 simultaneously detects the temperature of the output ends 101' of two adjacently placed DC terminals 101, which can reduce the use of NTC 102 and further save hardware materials. It should be understood that the plug-in positions of the output ends 101' of the DC terminals 101 on the PCB are designed to be adjacent to each other, so that the NTC 102 can be close to the output ends 101' of the two DC terminals 101, and the temperature of the NTC 102 is determined by the temperature of the DC terminal 101 with a higher temperature. When the temperature of one of the DC terminals 101 is abnormal, that is, when the detected temperature of the DC terminal 101 reaches the first alarm threshold, the controller MCU can receive a corresponding signal to issue an alarm.

[0109] Furthermore, the controller MCU may be the same controller as the controller 110 in the inverter 100. When the controller 100 identifies that a certain DC terminal 101 is abnormal, or that there is an abnormal terminal among certain DC terminals 101, that is, when the detected temperature of one or more DC terminals 101 reaches the first alarm threshold, the DC / DC conversion circuit 110 connected to these DC terminals 101 is controlled to reduce the input current of this DC / DC conversion circuit 110, thereby reducing the current flowing through the DC terminal 101 connected to this DC / DC conversion circuit 110, and further reducing the temperature of these DC terminals 101.

[0110] In another possible implementation, when the controller 100 recognizes that a certain DC terminal 101 is abnormal, or that there are abnormal terminals among certain DC terminals 101, that is, when the detection temperature of one or several DC terminals 101 reaches the first alarm threshold, the DC / DC conversion circuit 110 connected to these DC terminals 101 will be controlled to directly stop the DC / DC conversion circuit 110 from working, so that the input current of the DC / DC conversion circuit 110 is reduced to 0, thereby making the current flowing through the DC terminal 101 connected to the DC / DC conversion circuit 110 corresponding to 0, thereby reducing the temperature of these DC terminals 101.

[0111] In another possible implementation, reference Fig.15 , there are also multiple DC switches 103 in the inverter 100, and the DC switches 103 are connected between the DC terminals 101 and the DC / DC conversion circuits 110. Among them, the DC switches 103 are connected to two DC / DC conversion circuits 110, and each DC / DC conversion circuit 110 is connected to five DC inputs provided by photovoltaic modules 200, and each DC input provided by photovoltaic modules 200 corresponds to two DC terminals, that is, to ten DC terminals 101. In this way, the DC switch 103 can synchronously manage the DC inputs provided by the ten photovoltaic modules 200 corresponding to the two DC / DC conversion circuits 110, that is, control the electrical connection between the twenty DC terminals 101 and the two DC / DC conversion circuits 110. Among them, the controller 100 can control the on and off of the DC switch 103. When the controller 100 recognizes that a certain DC terminal 101 is abnormal, or there are abnormal terminals in several DC terminals 101, it can directly control the DC switch 103 to be disconnected, so that the input current of the two DC / DC conversion circuits 110 is reduced to 0, thereby making the current flowing through the DC terminals 101 connected to the two DC / DC conversion circuits 110 corresponding to 0, thereby reducing the temperature of these DC terminals 101.

[0112] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A power converter, characterized in that: It includes a plurality of DC terminals, a plurality of temperature detection units, a plurality of DC / DC (direct current / direct current) conversion circuits, at least one DC / AC (direct current / alternating current) conversion circuit, a PCB and a controller; The input ends of the plurality of DC terminals are used to be connected to a DC source, the output ends of the plurality of DC terminals are respectively connected to a plurality of connection points of the PCB, the connection points are respectively connected to the input ends of the plurality of DC / DC conversion circuits, the output ends of the plurality of DC / DC conversion circuits are connected to the input end of the at least one DC / AC conversion circuit, and the output end of the at least one DC / AC conversion circuit is used to be connected to a load; The plurality of temperature detection units and the connection points are alternately arranged on the PCB in a one-to-one or a one-to-two manner, and are used to detect the detection temperature of each corresponding DC terminal.

2. The power converter according to claim 1, characterized in that: The multiple temperature detection units, the multiple DC / DC conversion circuits and the at least one DC / AC conversion circuit are integrated on the one or more PCBs, and the output ends of the multiple DC terminals are electrically connected to the DC / DC conversion circuit through the PCB; the temperature detection unit includes multiple temperature detection branches and multiple operational amplifier circuits, and each of the temperature detection branches includes a DC source and a temperature sensing element; the DC source and the temperature sensing element of each temperature detection branch are connected in a one-to-one correspondence, wherein the DC source is connected to one end of the temperature sensing element, the other end of the temperature sensing element is connected to the input end of the operational amplifier circuit, and the output end of the operational amplifier circuit is connected to the signal input end of the controller.

3. The power converter according to claim 2, characterized in that: The temperature sensing element is NTC, and the temperature detection branch also includes a voltage divider resistor and a diode; The DC source and the temperature sensing element, the voltage divider resistor and the diode of each temperature detection branch are connected one by one, wherein the DC source is connected to one end of the NTC, the other end of the NTC is grounded through the voltage divider resistor, the other end of the NTC is also connected to the positive electrode of the diode, the negative electrode of the diode is connected to the positive input end of the operational amplifier circuit, and the negative input end of the operational amplifier circuit is connected to the output end of the operation method circuit.

4. The power converter according to claim 3, characterized in that: The NTC of each of the temperature detection branches is respectively arranged adjacent to the output end of at least one of the output ends of the plurality of DC terminals. The NTC is used to reduce the resistance value when the temperature of the output end of the corresponding at least one DC terminal increases, thereby increasing the potential value of the connection end of the NTC and the voltage-dividing resistor. There is a one-to-one correspondence between the potential value of the connection end of the NTC and the voltage-dividing resistor and the temperature of the output end of the DC terminal, that is, there is a one-to-one correspondence between the potential value of the connection end of the NTC and the voltage-dividing resistor and the detected temperature of the DC terminal.

5. The power converter according to claim 2 or 3, characterized in that: The NTC of each temperature detection branch is respectively arranged adjacent to the output ends of two corresponding DC terminals among the output ends of the multiple DC terminals, and the NTC is used to reduce the resistance value when the temperature of the output ends of the corresponding two DC terminals increases, thereby increasing the potential value of the connection end of the NTC and the voltage divider resistor.

6. The power converter according to any one of claims 2 or 3, characterized in that: The cathode of the diode of each of the plurality of temperature detection branches is connected to the cathode of the diode of an adjacent temperature detection branch.

7. The power converter according to any one of claims 1 to 4, characterized in that: including a plurality of DC switches; Each of the DC switches is connected between corresponding DC terminals among the DC terminals and corresponding two DC / DC conversion circuits.

8. The power converter according to any one of claims 1 to 4, characterized in that: including a housing; One end of the DC terminal is arranged on the housing of the power converter, and the other end of the DC terminal is plugged into the connection point of the PCB.

9. The power converter according to any one of claims 1 to 4, characterized in that: The DC source is a photovoltaic module, and each DC / DC conversion circuit is connected to 5 DC inputs provided by the photovoltaic module, and each DC input provided by the photovoltaic module corresponds to 2 DC terminals.

10. The power converter according to any one of claims 1 to 4, characterized in that: comprising a housing and a plurality of fans; The input ends of the plurality of DC terminals are arranged on the housing, and the PCB is accommodated inside the housing; The multiple fans are located on the housing of the power converter, and the multiple fans and the multiple DC terminals are arranged in parallel on the housing.

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