A power tube temperature detection circuit, an inverter and an inverter derating method

Abstract

The application provides a power tube temperature detection circuit, an inverter and an inverter derating method. In each DC / DC conversion circuit and inverter circuit of the inverter, at least one temperature detection unit is arranged corresponding to each power tube. The temperature detection unit is arranged near the power tube. The temperature of the power tube is detected by detecting the temperature of the power tube. After receiving the temperature information fed back by the temperature detection unit, the sampling control unit controls the corresponding DC / DC conversion circuit to derate based on the preset condition, so that the temperature of the corresponding power tube is below the safe temperature, and the use safety of the power tube and the stable and efficient operation of the inverter are ensured.

Description

Technical Field

[0001] This application relates to the field of inverters, and more particularly to a power transistor temperature detection circuit, an inverter, and an inverter derating method. Background Technology

[0002] With environmental and energy crises becoming global challenges, new energy sources such as wind and solar power have naturally become important ways to improve the energy structure and solve energy problems. Inverters, as a crucial component of new energy power generation solutions, are rapidly developing towards higher efficiency, reliability, and lower cost.

[0003] For inverters, efficiency and temperature control are key control points to ensure their long-term stable and efficient operation. The stable operation of power transistors is the foundation for ensuring the safe operation of the inverter. However, due to long-term high-frequency operation, power transistors may face aging and overheating, which can lead to device damage. In practical applications, it is necessary to pay attention to the operating status of the power transistors and adjust the input and output power of the inverter to reduce the working pressure on the power transistors, ensure that the power transistor temperature does not exceed the standard, and balance efficiency and reliability. Summary of the Invention

[0004] This application provides a temperature detection circuit, an inverter, and an inverter derating method, which can ensure the safe use of electrical components such as power transistors in the inverter while maintaining high overall efficiency.

[0005] In a first aspect, this application provides a power transistor temperature detection circuit, characterized in that it includes: a temperature detection unit and a sampling control unit; the temperature detection unit and the power transistor are disposed on the same PCB; wherein, the power transistor includes at least one first power transistor distributed in at least one DC / DC conversion circuit; the temperature detection unit is configured to correspond one-to-one with the first power transistor, and is used to detect the temperature of the first power transistor and feed back the temperature information of the first power transistor to the sampling control unit; the sampling control unit is used to control the output power of the DC / DC conversion circuit where the first power transistor is located based on the temperature information of the first power transistor.

[0006] It's understandable that inverters typically include a DC / DC converter circuit as the pre-amplifier circuit. This DC / DC converter circuit boosts / bucks the DC power from the renewable energy generation equipment and transmits the processed DC power to the inverter circuit. The inverter circuit then converts the received DC power into AC power and supplies it to the grid or loads. When the renewable energy generation equipment generates a large amount of power or operates continuously for a long time, the output power or operating time of the DC / DC converter and inverter circuits increase accordingly. At this time, the power transistors in the DC / DC converter and inverter circuits will be subjected to higher operating pressure, potentially causing their temperatures to rise above a certain threshold. Considering factors such as the operating environment and duration of use, in severe cases, exceeding the temperature threshold can directly lead to power transistor failure, potentially causing the inverter to burn out. Therefore, a power transistor temperature detection circuit needs to be installed on the PCB board where the power transistors are located to detect their temperature. Based on this temperature information, the output power of the DC / DC converter circuit is controlled. This power control typically involves reducing the output power of the DC / DC converter circuit to ensure the safety of the power transistors in both the DC / DC converter and inverter circuits.

[0007] Therefore, to achieve precise control of the output power of the DC / DC converter circuit, this application includes a power transistor temperature detection circuit for at least one power transistor in each DC / DC converter circuit. Based on the temperature information fed back by the temperature detection unit on this power transistor temperature detection circuit, it can be determined whether power control of the corresponding DC / DC converter circuit is required. This precise and independently detecting temperature circuit can accurately determine the power control requirements of each DC / DC converter circuit, and each DC / DC converter circuit can perform independent power control based on its independent power control requirements, without interference between them.

[0008] It should be understood that since the output power of each DC / DC converter circuit may be different under normal operating conditions, the specifications of the power transistors configured on each DC / DC converter circuit may also be different.

[0009] In one possible implementation, the power transistor further includes at least one second power transistor distributed on the inverter circuit. The temperature detection unit is configured to correspond one-to-one with the second power transistor, and is used to detect the temperature of the second power transistor and feed back the temperature information of the second power transistor to the sampling control unit. The sampling control unit is used to control the output power of part or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit based on the temperature information of the second power transistor.

[0010] Understandably, the input power of an inverter circuit is typically the sum of the output power of the preceding DC / DC converter circuit. Therefore, the specifications of the power transistors in the inverter circuit are usually different from those in the preceding DC / DC converter circuit. Ensuring the power transistors in the preceding DC / DC converter circuit are in a safe operating state does not guarantee the safe operating state of the power transistors in the inverter circuit. Therefore, temperature monitoring can be performed on one or more power transistors in the inverter circuit. When the temperature of a power transistor in the inverter circuit is abnormal, the input power of the inverter circuit needs to be reduced to bring the power transistors back to normal operating conditions. It should be understood that there are multiple strategies for reducing the input power of the inverter circuit. The output power of some preceding DC / DC converter circuits can be reduced, or the output power of all preceding DC / DC converter circuits can be reduced. By setting different control strategies, it is possible to minimize power conversion control while ensuring the safe operation of the power transistors in the inverter circuit and thus the normal operation of the inverter circuit, thereby reducing power loss caused by frequent control.

[0011] In one possible implementation, the sampling control unit is used to: control part or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit to reduce the output power when the temperature of the second power transistor exceeds a first temperature threshold, or when the temperature of the second power transistor exceeds a second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds a sudden change threshold; wherein the first temperature threshold is greater than the second temperature threshold.

[0012] It is understandable that the magnitude of the first and second temperature thresholds, the length of the continuous period, and the setting of the sudden change threshold can be determined by comprehensively considering the overall operating environment of the inverter and the specifications and characteristics of the power transistors. Therefore, the abnormal temperature conditions of the power transistors in each DC / DC circuit may vary depending on their respective operating conditions. That is, the first temperature threshold, second temperature threshold, length of the continuous period, and sudden change threshold corresponding to the power transistors in each DC / DC circuit may all be different. Similarly, the first temperature threshold, second temperature threshold, length of the continuous period, and sudden change threshold of the power transistors in the inverter circuit may also be different.

[0013] It should be noted that the first temperature threshold can be set relatively close to the power transistor's extreme temperature. When the power transistor's temperature exceeds the extreme temperature, it may be damaged immediately. Therefore, when the power transistor's temperature exceeds the first temperature threshold, it is a relatively urgent situation, requiring immediate reduction of the output power of the DC / DC converter circuit. The second temperature threshold is also set close to the power transistor's extreme temperature, but lower than the first temperature threshold. When the power transistor's temperature exceeds the second temperature threshold for a continuous period, it means that the power transistor is operating at a high voltage for a continuous period. If the high voltage operation continues, the power transistor's temperature may rise above the first temperature threshold. To minimize the occurrence of such an emergency, the output power of the DC / DC converter circuit should also be reduced in this situation to reduce the operating pressure on the power transistor, thereby reducing its temperature and ensuring its safety, thus achieving safe and stable operation of the inverter. When the power transistor's temperature changes significantly within a unit of time, it means that the power transistor's temperature may rise rapidly to exceed the second temperature threshold or even the first temperature threshold. Therefore, in this case, the output power of the DC / DC converter circuit containing the power transistor can also be reduced.

[0014] In one possible implementation, the sampling control unit is configured to: control all DC / DC converter circuits in the at least one DC / DC converter circuit to reduce their output power when the temperature of the second power transistor exceeds a first temperature threshold; or, control the DC / DC converter circuit in the at least one DC / DC converter circuit whose first power transistor temperature exceeds a third temperature threshold to reduce its output power when the temperature of the second power transistor exceeds a second temperature threshold but is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds a sudden change threshold; wherein the third temperature threshold is lower than the second temperature threshold.

[0015] It should be understood that when the temperature of the power transistor in the inverter circuit becomes abnormal, the purpose of power control of the preceding DC / DC converter circuit is to reduce the temperature of the power transistor in the inverter circuit to a safe range. When the temperature of the power transistor in the inverter circuit exceeds the first temperature threshold, it is a relatively urgent situation. Reducing the output power of the entire preceding DC / DC converter circuit can quickly reduce the input power of the inverter circuit, thereby reducing the operating stress on the power transistor and ensuring its safety. When the temperature of the power transistor in the inverter circuit only exceeds the second temperature threshold for a period of time, or the temperature change per unit time exceeds the sudden change threshold, a portion of the preceding DC / DC converter circuit can be selected for output power reduction control. The selection criterion is whether the third temperature threshold is exceeded. In this case, the output power of the DC / DC converter circuit whose power transistor temperature exceeds the third temperature threshold needs to be reduced. The third temperature threshold is lower than the second temperature threshold. The difference between the third and second temperature thresholds can be set according to specific circumstances in practical applications, and this application does not impose any restrictions.

[0016] In one possible implementation, the temperature detection unit and its corresponding power tube are connected via a heat-conducting structure.

[0017] By connecting the power transistor and the temperature sensing unit through a thermally conductive structure, the temperature difference between the sensing point and the power transistor itself can be reduced, further improving the accuracy of the temperature sensing unit in detecting the corresponding power transistor temperature. This thermally conductive structure design allows for direct measurement of the power transistor temperature, rather than obtaining a rough value through coefficient conversion from other sensing points. This not only avoids the need to use a more expensive power transistor with an integrated NTC (Negative Temperature Coefficient), but also achieves precise detection and fine control.

[0018] In one possible implementation, the heat-conducting structure is disposed inside or on the surface of the PCB board, and the pins of the power transistor are connected to the heat-conducting structure; the temperature detection unit is attached to the heat-conducting structure.

[0019] It should be noted that the above-described embodiments are just some of the possible embodiments included in this application. The above-described embodiments can be implemented individually or in combination, and this application does not impose any restrictions.

[0020] Secondly, this application provides an inverter, characterized in that it includes: at least one temperature detection unit, a sampling control unit, at least one DC / DC conversion circuit and an inverter circuit; the DC / DC conversion circuit is used to adjust the DC power input to the DC / DC conversion circuit and output it to the inverter circuit; the inverter circuit is used to receive the DC power output from the at least one DC / DC conversion circuit and convert the received DC power into AC power; at least one first power transistor in each DC / DC conversion circuit is configured with one temperature detection unit; the temperature detection unit and its corresponding first power transistor are disposed on the same PCB, used to detect the temperature of the first power transistor and feed back the temperature information of the first power transistor to the sampling control unit; the sampling control unit is used to control the output power of the DC / DC conversion circuit where the first power transistor is located based on the temperature information of the first power transistor.

[0021] It should be understood that in practical applications, the pre-amplifier circuit of the inverter circuit may be one or more DC / DC converter circuits. In order to finely control the output power of the DC / DC converter circuit, at least one power transistor in each DC / DC converter circuit and inverter circuit should be equipped with a power transistor temperature detection circuit. Based on the temperature data fed back by the temperature detection unit on the power transistor temperature detection circuit, it can be determined whether power control of the DC / DC converter circuit is required.

[0022] In one possible implementation, at least one second power transistor in the inverter circuit is configured with a corresponding temperature detection unit; the temperature detection unit and its corresponding second power transistor are disposed on the same PCB, and are used to detect the temperature of the second power transistor and feed back the temperature information of the second power transistor to the sampling control unit; the sampling control unit is used to control the output power of part or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit based on the temperature information of the second power transistor.

[0023] Understandably, the input power of an inverter circuit is typically the sum of the output power of the preceding DC / DC converter circuits. When the temperature of the power transistors in the inverter circuit is abnormal, it is necessary to reduce the input power of the inverter circuit to bring the power transistors back to normal operating conditions. It should be understood that there are various strategies for reducing the input power of the inverter circuit. This can involve reducing the output power of some preceding DC / DC converter circuits or reducing the output power of all preceding DC / DC converter circuits. By setting different control strategies, it is possible to minimize power conversion control while ensuring the safe operation of the power transistors in the inverter circuit and thus guaranteeing the normal operation of the inverter circuit, thereby reducing power loss caused by frequent control.

[0024] In one possible implementation, the sampling control unit is configured to: control the DC / DC converter circuit containing the first power transistor to reduce the output power when the temperature of the first power transistor exceeds a first temperature threshold, or when the temperature of the first power transistor exceeds a second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the first power transistor per unit time exceeds a sudden change threshold; wherein the first temperature threshold is greater than the second temperature threshold.

[0025] In one possible implementation, the sampling control unit is used to: control part or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit to reduce the output power when the temperature of the second power transistor exceeds a first temperature threshold, or when the temperature of the second power transistor exceeds a second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds a sudden change threshold; wherein the first temperature threshold is greater than the second temperature threshold.

[0026] It is understandable that the magnitude of the first and second temperature thresholds, the length of the continuous period, and the setting of the sudden change threshold can be determined by comprehensively considering the overall operating environment of the inverter and the specifications and characteristics of the power transistors. Therefore, the abnormal temperature conditions of the power transistors in each DC / DC circuit may vary due to their different specifications and preset operating conditions. That is, the first temperature threshold, second temperature threshold, length of the continuous period, and sudden change threshold corresponding to the power transistors in each DC / DC circuit may all be different. Similarly, the first temperature threshold, second temperature threshold, length of the continuous period, and sudden change threshold of the power transistors in the inverter circuit may also be different.

[0027] In one possible implementation, the sampling control unit is configured to: when the temperature of the second power transistor exceeds a first temperature threshold, control all DC / DC conversion circuits in the at least one DC / DC conversion circuit to reduce their output power; or, when the temperature of the second power transistor exceeds a second temperature threshold but is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds a sudden change threshold, control the DC / DC conversion circuit in the at least one DC / DC conversion circuit whose first power transistor temperature exceeds a third temperature threshold to reduce its output power; wherein the third temperature threshold is lower than the second temperature threshold.

[0028] It should be understood that when the temperature of the power transistor in the inverter circuit becomes abnormal, the purpose of power control of the preceding DC / DC converter circuit is to reduce the temperature of the power transistor in the inverter circuit to a safe range. When the temperature of the power transistor in the inverter circuit exceeds the first temperature threshold, it is a relatively urgent situation. Reducing the output power of the entire preceding DC / DC converter circuit can quickly reduce the input power of the inverter circuit, thereby reducing the operating stress on the power transistor and ensuring its safety. When the temperature of the power transistor in the inverter circuit only exceeds the second temperature threshold for a period of time, or the temperature change per unit time exceeds the sudden change threshold, a portion of the preceding DC / DC converter circuit can be selected for output power reduction control. The selection criterion is whether the third temperature threshold is exceeded. In this case, the output power of the DC / DC converter circuit whose power transistor temperature exceeds the third temperature threshold needs to be reduced. The third temperature threshold is lower than the second temperature threshold. The difference between the third and second temperature thresholds can be set according to specific circumstances, and this application does not impose any restrictions.

[0029] It should be noted that the above-described embodiments are just some of the possible embodiments included in this application. The above-described embodiments can be implemented individually or in combination, and this application does not impose any restrictions.

[0030] Thirdly, this application provides a method for temperature detection and derating of an inverter, characterized in that: the inverter includes: at least one temperature detection unit, a sampling control unit, at least one DC / DC conversion circuit, and an inverter circuit; each circuit in the at least one DC / DC conversion circuit has at least one first power transistor corresponding to one of the temperature detection units; the method includes: The temperature detection unit detects the temperature of its corresponding first power transistor; The temperature detection unit feeds back the temperature of the corresponding power transistor it detects to the sampling control unit; The sampling control unit controls the output power of the DC / DC converter circuit containing the first power transistor based on the temperature information of the power transistor.

[0031] It should be understood that the method provided in this application can achieve independent derating of each DC / DC converter circuit. Each DC / DC converter circuit selects at least one power transistor and configures it with a temperature detection unit. The temperature detection unit collects the temperature of each power transistor and independently feeds it back to the sampling control unit. Based on the feedback from the temperature detection unit, the sampling control unit independently performs power control on each DC / DC converter circuit, thereby ensuring the safe use of the power transistors.

[0032] In one possible embodiment, when the temperature of the first power transistor exceeds a first temperature threshold, or when the temperature of the power transistor exceeds a second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the power transistor per unit time exceeds a sudden change threshold, the sampling control unit controls the DC / DC conversion circuit where the first power transistor is located to reduce the output power; wherein, the first temperature threshold is greater than the second temperature threshold.

[0033] It should be understood that the method provided in this application can select different strategies to reduce output power based on different operating conditions of the power transistor. The first temperature threshold, the second temperature threshold, and the sudden change threshold can be set specifically according to the specific situation, which can ensure timely derating control of the corresponding DC / DC conversion circuit.

[0034] In one possible embodiment, at least one second power transistor in the inverter circuit is configured with a corresponding temperature detection unit; when the temperature of the second power transistor exceeds a first temperature threshold, or when the temperature of the power transistor exceeds a second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the power transistor per unit time exceeds a sudden change threshold, the sampling control unit controls some or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit to reduce the output power; wherein, the first temperature threshold is greater than the second temperature threshold.

[0035] It should be understood that the method provided in this application can also derating the inverter circuit based on monitoring its operating conditions. Specifically, this is achieved by reducing the output power of all or part of the upstream DC / DC converter circuit, i.e., the input power of the inverter. The first temperature threshold, second temperature threshold, and sudden change threshold of the power transistors on the inverter circuit also need to be set specifically according to the specific situation to trigger the derating control action at the optimal time. This application does not impose any restrictions on the specific settings.

[0036] In one possible embodiment, when the temperature of the second power transistor exceeds a first temperature threshold, the sampling control unit controls all DC / DC converter circuits in the at least one DC / DC converter circuit to reduce their output power; or, when the temperature of the power transistor exceeds a second temperature threshold but is less than the first temperature threshold for a continuous period of time, or when the temperature change of the power transistor per unit time exceeds a sudden change threshold, the DC / DC converter circuit in the at least one DC / DC converter circuit whose temperature of the first power transistor exceeds a third temperature threshold is controlled to reduce its output power; wherein, the third temperature threshold is lower than the second temperature threshold.

[0037] It should be understood that the method provided in this application, due to its ability to finely control the independent derating of each DC / DC converter circuit, allows for targeted selection of strategies to reduce the output power of the preceding DC / DC converter circuits during inverter circuit derating control. When the temperature of the power transistors in the inverter circuit exceeds the first temperature threshold, selecting to reduce the output power of all preceding DC / DC converter circuits can quickly reduce the input power of the inverter circuit, thereby reducing the operating stress on the power transistors and ensuring their safety. When the temperature of the power transistors in the inverter circuit only exceeds the second temperature threshold for a period of time or the temperature change per unit time exceeds the sudden change threshold, a portion of the preceding DC / DC converter circuits can be selected for output power derating control. The selection criterion is whether the third temperature threshold is exceeded, which is lower than the second temperature threshold. The difference between the third and second temperature thresholds can be set according to specific circumstances in practical applications, and this application does not impose any restrictions. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a power transistor temperature detection circuit provided in an embodiment of this application; Figure 2 This is a schematic diagram of a power transistor temperature detection circuit with a thermally conductive structure provided in an embodiment of this application; Figure 3 This is a schematic diagram illustrating the arrangement of a heat-conducting structure on a PCB according to an embodiment of this application; Figure 4 This is a schematic diagram of an inverter provided in an embodiment of this application; Figure 5 This is a flowchart of an inverter derating method provided in an embodiment of this application. Detailed Implementation

[0039] For ease of understanding, the terminology used in the embodiments of this application will be explained first.

[0040] And / or: such as A and / or B, refers to three possibilities: A or B, or A and B.

[0041] Multiple: refers to two or more.

[0042] Connection: should be interpreted broadly. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through an intermediary.

[0043] The specific embodiments of this application will now be clearly described in conjunction with the accompanying drawings.

[0044] With environmental and energy crises becoming global challenges, new energy power generation solutions have naturally become an important way to improve the energy structure and solve energy problems. Inverters, as an important part of new energy power generation solutions, are developing rapidly towards high efficiency, reliability, and low cost.

[0045] For inverters, efficiency and temperature control are key control points to ensure their long-term stable and efficient operation. It is usually necessary to collect the temperature of the power transistors and take corresponding control strategies to reduce the output power based on temperature thresholds, so as to ensure the normal operation of the power transistors, thereby ensuring the stable and normal operation of the inverter and improving the inverter's efficiency and reliability.

[0046] Based on this, the embodiments of this application first provide a power tube temperature detection circuit, which can be used in an inverter. Typically, the inverter is used to convert the DC power transmitted from the new energy power generation equipment into AC power, and finally transmit it to the power grid or load, etc.

[0047] like Figure 1 As shown, the temperature detection circuit 110 is installed in the inverter, specifically in the DC / DC conversion circuit 120 or the inverter circuit 130. The power transistor temperature detection circuit 110 includes a temperature detection unit 112 and a sampling control unit 113. When the power transistors 111 being detected are distributed on at least one DC / DC conversion circuit 120, the temperature detection unit 112 is configured in a one-to-one correspondence with each power transistor 111. The temperature detection unit 112 detects the temperature of at least one power transistor 111 on the DC / DC conversion circuit 120. The temperature detection unit 112 and the power transistor 111 are on the same PCB board, typically located near the power transistor 111. After detecting the temperature of the power transistor 111, the temperature detection unit 112 feeds back the detected temperature information to the sampling control unit 113. Upon receiving the temperature information, the sampling control unit 113 controls the output power of the DC / DC conversion circuit 120 where the power transistor 111 is located, thereby achieving the purpose of regulating the power transistor temperature.

[0048] When the power transistors 111 being tested are distributed on the inverter circuit 130 of the inverter, the power transistor temperature detection circuit 110 includes a temperature detection unit 112 and a sampling control unit 113. The temperature detection unit 112 detects the temperature of at least one power transistor on the inverter circuit 130. The temperature detection unit 112 is set up one-to-one with the power transistors 111. The temperature detection unit 112 and the power transistors 111 are on the same PCB board and are usually located near the power transistors 111. After detecting the temperature of the power transistors 111, the temperature detection unit 112 feeds back the detected temperature information to the sampling control unit 113. After receiving the temperature information, the sampling control unit 113 controls the output power of part or all of the DC / DC conversion circuit 120 according to the temperature information, thereby achieving the purpose of adjusting the temperature of the power transistors 111 on the inverter circuit 130.

[0049] It should be noted that since the output power of the inverter circuit 130 is determined by its input power, and the input power of the inverter circuit 130 is equal to the sum of the output power of the preceding DC / DC converter circuit 120, the output power of the inverter circuit 130 can be controlled by controlling the output power of the preceding DC / DC converter circuit 120. This, in turn, adjusts the temperature of the power transistor 111 in the inverter circuit 130, ensures the normal operation of the power transistor 111, and ensures the stable operation of the inverter.

[0050] It should be noted that, Figure 1 The purpose is merely to illustrate the connection relationship of the temperature detection circuit, and not to make specific limitations on the connection position, specific structure and quantity of each device and unit.

[0051] Optionally, such as Figure 2 As shown, the power transistor 111 and the temperature detection unit 112 are connected by a heat-conducting structure 114. Through the connection of the heat-conducting structure, the temperature information of the power transistor 111 can be measured more accurately.

[0052] It should be noted that, Figure 2 The purpose is merely to illustrate the connection relationship of the temperature detection circuit, and not to make specific limitations on the connection position, specific structure and quantity of each device and unit.

[0053] Optionally, such as Figure 3As shown, the power transistor can be an Insulated Gate Bipolar Transistor (IGBT), the temperature sensing unit can be an NTC, and the thermal structure can be a thermally conductive copper plate. The thermally conductive copper plate can be attached to the upper or lower surface of the PCB board, or it can be embedded inside the PCB board. The IGBT pins are connected to the thermally conductive copper plate, and the temperature sensing unit is also attached to the thermally conductive copper plate. Because the NTC occupies little space, it can be placed in a safe location close to the power transistor. The temperature change of the power transistor can be reflected in the temperature change of the NTC in a timely manner. Since there is a one-to-one correspondence between the temperature of the NTC and its resistance value, by measuring the resistance value of the NTC, the temperature of the NTC can be determined, which is equivalent to measuring the temperature of the power transistor.

[0054] It should be noted that, Figure 3 The purpose is merely to illustrate the connection relationship of the temperature detection circuit, and is not to make specific limitations on the connection position, specific structure and quantity of each device and unit, nor to restrict the selection of each device.

[0055] The temperature detection circuit provided in the foregoing embodiments performs power control on the DC / DC converter circuit based on the temperature of the power transistors in the DC / DC converter circuit or inverter circuit, including the following methods: The first power control method: In some embodiments, at least one power transistor in each DC / DC converter circuit is equipped with a temperature detection unit. When the temperature of the power transistor 111 on the DC / DC converter circuit 120 exceeds the first temperature threshold T1 or for a continuous period of time t, the power control unit will detect the temperature of the transistor. m Exceeding the second temperature threshold T2 and less than the first temperature threshold T1, or the temperature change per unit time exceeding the abrupt change threshold ΔT m The sampling control unit directly controls the DC / DC converter circuit 120 containing the power transistor to reduce its output power. This derating strategy effectively controls the temperature of the power transistor 111 in the DC / DC converter circuit 120, ensuring its normal operation and preventing excessive output power. Consequently, the input power received by the inverter circuit 130 is also prevented from becoming excessive, thus guaranteeing its normal operation to a certain extent.

[0056] The second power control method: In some implementations, the power transistors on the inverter circuit are also equipped with temperature detection units. When the temperature of the power transistor 111 on the inverter circuit 130 exceeds the first temperature threshold T1 or for a continuous period of time t... m Exceeding the second temperature threshold T2 and less than the first temperature threshold T1, or the temperature change per unit time exceeding the abrupt change threshold ΔT mThe sampling control unit 113 controls some or all of the circuits in the DC / DC converter circuit 120 to reduce the output power. This derating strategy for the inverter circuit 130 can be used to deal with the special situation where the power transistor 111 in the DC / DC converter circuit 120 is operating normally but the power transistor 111 in the inverter circuit 130 is operating abnormally, and the additional cost is not much, which can further ensure the stable and efficient operation of the inverter.

[0057] The third power control method: In some implementations, power control can be performed by simultaneously considering the temperatures of the power transistors in the inverter circuit and the DC / DC converter circuit. When the temperature of the power transistor 111 in the inverter circuit 130 exceeds the first temperature threshold T1, the sampling control unit will control all circuits in the DC / DC converter circuit 120 to reduce the output power; or, when the temperature of the power transistor 111 in the inverter circuit 130 exceeds the second temperature threshold T2 but is less than the first temperature threshold T1 or a unit, t m The internal temperature change exceeds the mutation threshold ΔT m The sampling control unit will reduce the output power of the circuit in the DC / DC converter circuit 120 when the temperature of the power transistor 111 exceeds the third temperature threshold T3. This derating strategy takes different measures for different temperature conditions of the power transistor 111 in the inverter circuit 130. This refined control strategy can not only ensure the normal operation of the inverter, but also reduce the energy consumption caused by frequent derating control, thereby further improving the overall efficiency of the inverter.

[0058] In the aforementioned control methods, flexible derating strategies are achieved by setting different temperature thresholds and other parameters. In specific implementation, one of these control methods can be used, or a combination of several of the aforementioned control methods can be combined. This application does not impose any limitations. Furthermore, the first temperature threshold T1, the second temperature threshold T2, the third temperature threshold T3, and the time threshold t mentioned in the embodiments of this application... m Temperature change threshold ΔT m Where T1 > T2 > T3, T1, T2, T3, t m and ΔT m All settings can be configured through experimental testing, comprehensive experimental results, and specific inverter safety control requirements; this application does not impose any limitations. This application also provides an inverter embodiment; please refer to [link to relevant documentation]. Figure 4 Taking photovoltaic power generation as an example, one can understand the specific application of the temperature detection circuit provided in this application on the inverter, such as the distribution of the sampling control unit and temperature detection unit in each DC / DC conversion circuit and inverter circuit, as well as the connection relationship of each unit.

[0059] exist Figure 4In the inverter shown, the DC / DC converter circuit receives the DC power generated by the solar photovoltaic panel and performs boost / buck processing on the received DC power before outputting it to the inverter circuit. The inverter circuit receives the DC power output from the preceding DC / DC converter circuit and converts the received DC power into AC power for output.

[0060] like Figure 4 The diagram shows an inverter with 1 to n DC / DC conversion circuits. In practical applications, the inverter may have only one DC / DC conversion circuit. Each DC / DC conversion circuit and inverter circuit may have one temperature detection unit to detect the temperature of one of the power transistors, or multiple temperature detection units to detect the temperature of multiple power transistors. The temperature detection units and power transistors are set up in a one-to-one correspondence.

[0061] It should be noted that, Figure 4 The purpose is merely to illustrate the connection relationship of some units in the inverter of this embodiment, and is not to specifically limit the connection position, specific structure and quantity of each device, component and unit.

[0062] Optionally, each DC / DC converter circuit is equipped with at least one temperature detection unit. This unit detects the temperature of at least one power transistor in that DC / DC converter circuit and feeds the detected temperature information back to the sampling control unit. Upon receiving the temperature information, the sampling control unit controls the output power of the DC / DC converter circuit based on this information, thereby regulating the power transistor temperature. The specific method by which the sampling control unit controls the output power of the DC / DC converter circuit can be referred to the first power control method provided in the aforementioned embodiments.

[0063] Optionally, at least one temperature detection unit is provided on the inverter circuit. This unit detects the temperature of at least one power transistor on the inverter circuit and feeds the detected temperature information back to the sampling control unit. Upon receiving the temperature information, the sampling control unit controls the output power of part or all of the DC / DC converter circuit based on this information, thereby regulating the temperature of the power transistors on the inverter circuit. The specific method by which the sampling control unit controls the output power of the DC / DC converter circuit can refer to the first and / or second and / or third power control methods provided in the foregoing embodiments.

[0064] Embodiments of this application also provide an inverter derating method, which is applied to the inverter in the foregoing embodiments.

[0065] The specific implementation method is as follows: the temperature detection unit detects the temperature of the power transistor in the DC / DC converter circuit and feeds back the temperature information of the power transistor to the sampling control unit. Based on the temperature information of the power transistor, the sampling control unit performs output power control on the DC / DC converter circuit. The specific method by which the sampling control unit performs output power control on the DC / DC converter circuit can refer to the first power control method provided in the foregoing embodiments.

[0066] Optionally, the temperature of the power transistors in the inverter circuit can be detected by a temperature detection unit corresponding to the power transistors, and the temperature information of the power transistors can be fed back to the sampling control unit. Based on the temperature information of the power transistors, the sampling control unit can control the output power of all or part of the DC / DC conversion circuit. The specific method by which the sampling control unit controls the output power of the DC / DC conversion circuit can refer to the first, second, and / or third power control methods provided in the foregoing embodiments.

[0067] In a specific embodiment, the above inverter derating method flow can be referred to Figure 5 .

[0068] Step S1: The temperature detection unit detects the temperature of the power transistor; Step S2: The temperature detection unit feeds back the detected temperature information to the sampling control unit, and then proceeds to step S3, step S4, or step S5. Step 3 S3: When the temperature of the power transistor in the DC / DC converter circuit exceeds the first temperature threshold T1, or for a continuous period of time t m Exceeding the second temperature threshold T2, or, the temperature change per unit time exceeding the abrupt change threshold ΔT. m The sampling control unit controls the DC / DC converter circuit to reduce the output power; Step 4 S4: When the temperature of the power transistor in the inverter circuit exceeds the first temperature threshold T1, the sampling control unit controls all DC / DC conversion circuits in the DC / DC conversion circuit to reduce the output power. Step 5 S5: When the power transistor temperature in the inverter circuit remains constant for a period of time t m Exceeding the second temperature threshold T2, or, the temperature change per unit time exceeding the abrupt change threshold ΔT. m The sampling control unit controls the DC / DC converter circuit to reduce the output power when the power transistor temperature exceeds the third temperature threshold T3.

[0069] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A power tube temperature detection circuit, characterized by comprising: include: A temperature detection unit and a sampling control unit; the temperature detection unit and the power transistor are disposed on the same printed circuit board (PCB); wherein the power transistor includes at least one first power transistor distributed in at least one DC / DC conversion circuit, and also includes at least one second power transistor distributed in the inverter circuit; The temperature detection unit is configured in a one-to-one correspondence with the first power transistor, and is used to detect the temperature of the first power transistor and feed back the temperature information of the first power transistor to the sampling control unit. The temperature detection unit is also configured to correspond one-to-one with the second power transistor, and is used to detect the temperature of the second power transistor and feed back the temperature information of the second power transistor to the sampling control unit; the sampling control unit is used to control the output power of the DC / DC converter circuit where the first power transistor is located based on the temperature information of the first power transistor. The sampling control unit is also used to control the output power of some or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit based on the temperature information of the second power tube. The sampling control unit is used for: When the temperature of the second power transistor exceeds a first temperature threshold, control all DC / DC converter circuits in the at least one DC / DC converter circuit to reduce their output power; or... When the temperature of the second power transistor exceeds the second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds the sudden change threshold, the output power of the DC / DC converter circuit in the at least one DC / DC converter circuit where the temperature of the first power transistor exceeds the third temperature threshold is reduced; wherein the third temperature threshold is lower than the second temperature threshold.

2. The power tube temperature detection circuit according to claim 1, wherein The sampling control unit is used for: When the temperature of the first power transistor exceeds the first temperature threshold, or when the temperature of the first power transistor exceeds the second temperature threshold but is less than the first temperature threshold for a continuous period of time, or when the temperature change of the first power transistor per unit time exceeds the sudden change threshold, the DC / DC conversion circuit containing the first power transistor is controlled to reduce the output power; wherein, the first temperature threshold is greater than the second temperature threshold.

3. The power tube temperature detection circuit of claim 1, wherein The sampling control unit is used for: When the temperature of the second power transistor exceeds the first temperature threshold, or when the temperature of the second power transistor exceeds the second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds the sudden change threshold, the output power of some or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit is reduced; wherein, the first temperature threshold is greater than the second temperature threshold.

4. The power tube temperature detection circuit according to any one of claims 1 to 3, characterized by: The temperature detection unit and its corresponding power tube are connected through a heat-conducting structure.

5. The power tube temperature detection circuit of claim 1, wherein: The temperature detection unit and its corresponding power tube are connected through a heat-conducting structure.

6. The power tube temperature detection circuit of claim 5, wherein: The heat-conducting structure is disposed inside or on the surface of the PCB board, and the pins of the power transistor are connected to the heat-conducting structure; the temperature detection unit is attached to the heat-conducting structure.

7. An inverter, characterized by comprising: include: At least one temperature detection unit, a sampling control unit, at least one DC / DC converter circuit and an inverter circuit; The DC / DC converter circuit is used to adjust the DC power input to the DC / DC converter circuit and output it to the inverter circuit; The inverter circuit is used to receive the DC power output from the at least one DC / DC converter circuit and convert the received DC power into AC power. In each of the DC / DC conversion circuits, at least one first power transistor is configured with one temperature detection unit. At least one second power transistor in the inverter circuit is configured with a corresponding temperature detection unit. The temperature detection unit and its corresponding first power transistor are mounted on the same PCB and are used to detect the temperature information of the first power transistor. The temperature detection unit and its corresponding second power transistor are mounted on the same PCB and are used to detect the temperature of the second power transistor. The temperature information of the first power transistor and the temperature information of the second power transistor are fed back to the sampling control unit. The sampling control unit is used to control the output power of the DC / DC converter circuit where the first power transistor is located based on the temperature information of the first power transistor. The sampling control unit is also used to control the output power of some or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit based on the temperature information of the second power tube. The sampling control unit is used for: When the temperature of the second power transistor exceeds a first temperature threshold, control all DC / DC converter circuits in the at least one DC / DC converter circuit to reduce their output power; or... When the temperature of the second power transistor exceeds the second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds the sudden change threshold, the output power of the DC / DC converter circuit in the at least one DC / DC converter circuit where the temperature of the first power transistor exceeds the third temperature threshold is reduced; wherein the third temperature threshold is lower than the second temperature threshold.

8. The inverter of claim 7, wherein, The sampling control unit is used for: When the temperature of the first power transistor exceeds the first temperature threshold, or when the temperature of the first power transistor exceeds the second temperature threshold but is less than the first temperature threshold for a continuous period of time, or when the temperature change of the first power transistor per unit time exceeds the sudden change threshold, the DC / DC conversion circuit containing the first power transistor is controlled to reduce the output power; wherein, the first temperature threshold is greater than the second temperature threshold.

9. The inverter of claim 7, wherein, The sampling control unit is used for: When the temperature of the second power transistor exceeds the first temperature threshold, or when the temperature of the second power transistor exceeds the second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds the sudden change threshold, the output power of some or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit is reduced; wherein, the first temperature threshold is greater than the second temperature threshold.

10. A method for derating an inverter, characterized in that: The inverter includes: at least one temperature detection unit, a sampling control unit, at least one DC / DC conversion circuit and an inverter circuit; each circuit in the at least one DC / DC conversion circuit has at least one first power transistor corresponding to one of the temperature detection units; at least one second power transistor in the inverter circuit has at least one temperature detection unit corresponding to one of the temperature detection units. The method includes: The temperature detection unit detects the temperature of its corresponding first power transistor; the temperature detection unit detects the temperature of its corresponding second power transistor. The temperature detection unit feeds back the temperature of the corresponding power transistor it detects to the sampling control unit; The sampling control unit controls the output power of the DC / DC converter circuit containing the first power transistor based on the temperature information of the first power transistor. Based on the temperature information of the second power transistor, the sampling control unit controls the output power of part or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit. When the temperature of the second power transistor exceeds a first temperature threshold, control all DC / DC converter circuits in the at least one DC / DC converter circuit to reduce their output power; or... When the temperature of the second power transistor exceeds the second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds the sudden change threshold, the output power of the DC / DC converter circuit in the at least one DC / DC converter circuit where the temperature of the first power transistor exceeds the third temperature threshold is reduced; wherein the third temperature threshold is lower than the second temperature threshold.

11. The method according to claim 10, characterized in that: When the temperature of the first power transistor exceeds the first temperature threshold, or when the temperature of the first power transistor exceeds the second temperature threshold but is less than the first temperature threshold for a continuous period of time, or when the temperature change of the first power transistor per unit time exceeds the sudden change threshold, the sampling control unit controls the DC / DC conversion circuit where the first power transistor is located to reduce the output power; wherein, the first temperature threshold is greater than the second temperature threshold.

12. The method of claim 10, wherein: When the temperature of the second power transistor exceeds the first temperature threshold, or when the temperature of the second power transistor exceeds the second temperature threshold and is less than the first temperature threshold for a continuous period of time, or when the temperature change of the second power transistor per unit time exceeds the sudden change threshold, the sampling control unit controls some or all of the DC / DC conversion circuits in the at least one DC / DC conversion circuit to reduce the output power; wherein, the first temperature threshold is greater than the second temperature threshold.

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