A method for temperature control in a power system and the power system

Abstract

This application discloses a temperature control method and a power system for a power system, belonging to the field of power electronics technology. The temperature control method first controls the first component controller in a first DC string whose temperature is higher than a first preset temperature to implement initial cooling. After the blocking time reaches a first preset duration, in response to the temperature of the first component controller being higher than a preset safe temperature, the string current of the first DC string is reduced, thereby further enhancing the cooling effect. When the temperature of each component controller in the first DC string is lower than or equal to the preset safe temperature, the string current of the first DC string is increased, allowing each component controller in the first DC string to return to its normal operating current. This application achieves effective cooling of the component controllers through the coordinated action of the blocking of the first component controller and the string current of the first DC string, while simultaneously improving the operational stability and reliability of the power system.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a temperature control method for a power system and a power system thereof. Background Technology

[0002] In power systems, DC power supplies are connected to power converters via component controllers. However, component controllers are typically exposed to complex outdoor environments for extended periods. Therefore, they are highly susceptible to high temperatures during operation, leading to a rapid increase in internal temperature and frequent high-temperature operation, which can significantly reduce the operational stability of the power system. Summary of the Invention

[0003] This application provides a temperature control method and a power system for a power system to reduce the temperature of component controllers.

[0004] In a first aspect, this application provides a temperature control method for a power system. The power system includes a power converter and a DC string. The power converter has at least one DC input terminal, and each DC input terminal is connected to a corresponding DC string. The DC string includes at least one component controller. The input terminal of each component controller is used to connect to a corresponding DC power supply. The output terminals of all component controllers in the DC string are connected in series and then connected to the corresponding DC input terminal. The AC output terminal of the power converter is used to connect to the power grid. Temperature control methods include: In response to the temperature of any component controller in the first DC string being higher than the first preset temperature, the first component controller is controlled to block the wave. The first component controller is the component controller in the first DC string whose temperature is higher than the first preset temperature. The first DC string is any DC string. After the first component controller is blocked for a first preset time, in response to the temperature of the first component controller being higher than the preset safe temperature, the string current of the first DC string is reduced. In response to the fact that the temperature of each component controller in the first DC string is lower than or equal to the preset safe temperature, the string current of the first DC string is increased.

[0005] In some embodiments, reducing the string current of the first DC string includes: Every first preset time interval, the string current of the first DC string is reduced by a preset current magnitude until the temperature of the controller of each component in the first DC string is lower than or equal to the preset safe temperature, or the string current is reduced to the minimum operating current.

[0006] In some embodiments, after reducing the string current of the first DC string, the temperature control method further includes: After a second preset time period, in response to the fact that the temperature of a component controller in the first DC string is higher than a preset safe temperature, each component controller in the first DC string is put into standby mode. In response to the temperature of each component controller in the first DC string being lower than or equal to the preset safe temperature, the controller of each component controller in the first DC string is powered on.

[0007] In some embodiments, after reducing the string current of the first DC string, the temperature control method further includes: After a second preset time period, in response to the fact that the temperature of the component controller in the first DC string is higher than the preset safe temperature, all component controllers are put into standby mode and the power converter is put into standby mode. When the temperature of all component controllers is below or equal to the preset safe temperature, the power converter is turned on and all component controllers are turned on.

[0008] In some embodiments, when the component controller is an optimizer, before controlling the first component controller to block the waveform after the temperature of any component controller in the first DC string exceeds a first preset temperature, the temperature control method further includes: Reduce the port input voltage at the input terminal of the first component controller; After reducing the port input voltage of the first component controller for a third preset time, in response to the first component controller being higher than a preset safe temperature, or in response to the first component controller being higher than or equal to a second preset temperature within the third preset time, the first component controller is controlled to block the wave, and the second preset temperature is higher than the first preset temperature.

[0009] In some embodiments, reducing the port input voltage at the input of the first component controller includes: Every first preset time interval, the port input voltage of the first component controller is reduced by a preset voltage magnitude until the temperature of the first component controller is lower than or equal to the preset safe temperature, or the port input voltage is reduced to the minimum operating voltage.

[0010] In some embodiments, after reducing the port input voltage at the input terminal of the first component controller and before controlling the first component controller to block the waveform, the temperature control method further includes: In response to the temperature of the first component controller being lower than or equal to a preset safe temperature, the port input voltage of the first component controller input terminal is increased.

[0011] In some embodiments, the temperature control method further includes: In response to the number of component controllers with temperatures higher than a first preset temperature exceeding a first threshold, the string current of the second DC string is reduced. The second DC string is the DC string containing the component controllers with temperatures higher than the first preset temperature. In response to the temperature of each component controller in all second DC strings being lower than or equal to the preset safe temperature, the string current of the second DC strings is increased.

[0012] In some embodiments, the temperature control method further includes: In response to the number of component controllers whose temperature is higher than the first preset temperature exceeding the second threshold, all component controllers are put into standby mode and the power converter is put into standby mode, where the second threshold is greater than the first threshold. In response to the fact that the temperature of all component controllers is lower than or equal to the preset safe temperature, the power converter is turned on and all component controllers are turned on.

[0013] In some embodiments, after controlling the first component controller to block the waveform and before reducing the string current of the first DC string, the temperature control method further includes: In response to the first component controller's temperature being lower than or equal to a preset safe temperature, the first component controller is controlled to generate waves normally.

[0014] In some embodiments, the component controller further includes a bypass circuit, and the temperature control method further includes: In response to the component controller not performing wave blocking, the control bypass circuit remains open. In response to the component controller blocking the waveform, the control bypass circuit switches to the on state.

[0015] Secondly, embodiments of this application also provide a power system, the power system comprising: The power converter and DC string are described. The power converter has at least one DC input terminal, and each DC input terminal is connected to a corresponding DC string. The DC string includes at least one component controller. The input terminal of each component controller is used to connect to the corresponding DC power supply. The output terminals of all component controllers in the DC string are connected in series and then connected to the corresponding DC input terminal. The AC output terminal of the power converter is used to connect to the power grid. The first component controller is configured to control the first component controller to block the wave in response to the temperature of any component controller in the first DC string being higher than the first preset temperature. The first component controller is the component controller in the first DC string whose temperature is higher than the first preset temperature. The first DC string is any DC string. The power converter is configured to, after blocking the first component controller for a first preset duration, reduce the string current of the first DC string in response to the temperature of the first component controller being higher than a preset safe temperature; and increase the string current of the first DC string in response to the temperature of each component controller in the first DC string being lower than or equal to the preset safe temperature.

[0016] This application provides a temperature control method for a power system. The method first controls the first component controller in a first DC string whose temperature is higher than a first preset temperature to implement initial cooling. After the blocking time reaches a first preset duration, in response to the first component controller's temperature exceeding a preset safe temperature, the string current of the first DC string is reduced, thereby further enhancing the cooling effect. When the temperature of each component controller in the first DC string is lower than or equal to the preset safe temperature, the string current of the first DC string is increased, allowing each component controller to return to its normal operating current. This application achieves effective cooling of the component controllers through the coordinated action of the first component controller blocking and the string current of the first DC string, while simultaneously improving the operational stability and reliability of the power system.

[0017] This application also provides a power system for implementing the above-described temperature control method. Therefore, the power system has all the technical features and beneficial effects of the above-described temperature control method, which will not be repeated here. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of a power system provided in this application embodiment; Figure 2 This application provides a schematic diagram of another power system structure. Figure 3 This is a schematic diagram of the component controller being an optimizer provided in an embodiment of this application; Figure 4 This is a closed-loop control architecture diagram of the optimizer provided in the embodiments of this application; Figure 5 This is a schematic diagram of the component controller being a shutdown device provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of the intelligent monitoring system for photovoltaic power plants provided in the embodiments of this application; Figure 7 A schematic flowchart of a temperature control method provided in an embodiment of this application; Figure 8 A schematic diagram of the voltage derating curve of the optimizer provided in this application embodiment at high temperature (65°C); Figure 9 A schematic diagram of the process for reducing port input voltage provided in an embodiment of this application; Figure 10 This is a schematic flowchart of another temperature control method provided in an embodiment of this application.

[0019] Explanation of reference numerals in the attached figures: 100. Power converter; 200. DC string; 210. Component controller; 211. Bypass circuit; 300. DC power supply; 400. Power Grid A. DC input terminal; B. AC output terminal. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0021] In the embodiments of this application, "at least one" refers to one or more; "multiple" refers to two or more. In the description of this application, the terms "first," "second," "third," etc., are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance, nor should they be construed as indicating or implying order.

[0022] References such as “one embodiment” or “some embodiments” as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the terms “comprising,” “including,” “having,” and variations thereof, as used in this specification, mean “including, but not limited to,” unless otherwise specifically emphasized.

[0023] It should be noted that in the embodiments of this application, "and / or" describes the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In addition, the character " / ", unless otherwise specified, generally indicates that the associated objects before and after it are in an "or" relationship.

[0024] It should be noted that in the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. 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 one or more other electrical components.

[0025] In power systems, DC power supplies are connected to power converters via component controllers. However, component controllers are typically exposed to complex outdoor environments for extended periods. Therefore, they are highly susceptible to high temperatures during operation, leading to a rapid increase in internal temperature and frequent high-temperature operation, which can significantly reduce the operational stability of the power system.

[0026] Taking the DC power supply provided by photovoltaic modules as an example, the working environment of the module controller is relatively harsh. It works outdoors all year round and is installed directly below the photovoltaic modules. The temperature and sunlight in the geographical environment vary greatly.

[0027] The module controller operates outdoors for extended periods, with ambient temperatures ranging from -40°C to 85°C and light intensity fluctuations ranging from 0 to 1000 W / m², often exceeding 30°C between day and night. During extreme high temperatures (such as midday in summer), the backsheet temperature of the photovoltaic module can reach over 70°C, directly causing a rapid rise in the internal temperature of the module controller. The junction temperature of power devices (such as MOSFETs) within the controller may exceed 150°C (far exceeding their rated junction temperature of 125°C), accelerating the aging rate of the devices (capacitor life is halved for every 10°C increase in temperature) and increasing the risk of short-circuit fires caused by insulation aging.

[0028] Component controllers are highly susceptible to high ambient temperatures during operation, which can lead to frequent high-temperature operation and potentially adverse consequences.

[0029] In some cases, prolonged operation at high temperatures can severely damage hardware components. Various hardware components have their own operating temperature ranges; exceeding these ranges can drastically reduce performance or even cause failure. For example, in a component controller, the electrolyte inside a capacitor evaporates more rapidly at high temperatures, leading to a significant decrease in capacitance and a substantial increase in leakage current. Ultimately, this causes the capacitor to lose its original filtering and energy storage functions, resulting in irreversible hardware damage. Furthermore, in a component controller, the resistance of a resistor changes significantly at high temperatures, deviating from its design value. This affects the operating parameters of the entire circuit, causing malfunctions and further accelerating the aging and failure of other related components.

[0030] In other examples, prolonged operation at high temperatures can cause the component controller to overheat abnormally, with heat continuously accumulating. When the temperature rises to a certain level, it may ignite surrounding flammable materials, such as the plastic supports under the photovoltaic modules and the insulation of cables. These materials are highly flammable at high temperatures, which can lead to unexpected fires, causing significant property damage and safety hazards.

[0031] In view of the above, embodiments of this application provide a temperature control method and a power system for a power system, aiming to solve at least one of the above-mentioned technical problems.

[0032] Please see Figure 1 and Figure 2 , Figure 1 A schematic diagram of the structure of a power system provided in this application embodiment; Figure 2 This is a schematic diagram of another power system provided in an embodiment of this application.

[0033] This application provides a power system including a power converter 100 and a DC string 200. The power converter 100 has at least one DC input terminal A, and each DC input terminal A is connected to a corresponding DC string 200. The DC string 200 includes at least one component controller 210. The input terminal of each component controller 210 is used to connect to a corresponding DC power supply 300. The output terminals of all component controllers 210 in the DC string 200 are connected in series to the corresponding DC input terminal A. The AC output terminal B of the power converter 100 is used to connect to the power grid 400.

[0034] The power converter 100 has at least one DC input terminal A, each DC input terminal A being connected to a corresponding DC string 200. The AC output terminal B of the power converter 100 is used to connect to the power grid 400, realizing DC-to-AC conversion and grid-connected output. For example, the power converter 100 internally includes multiple independent DC-DC conversion circuits (such as Boost circuits) and AC-DC conversion circuits (such as inverter circuits). The input terminal of each DC-DC conversion circuit corresponds to a DC input terminal A, and the output terminal of each DC-DC conversion circuit is connected in parallel to the input terminal of the AC-DC conversion circuit. The output terminal of the AC-DC conversion circuit is used to connect to the power grid 400. Both the DC-DC conversion circuits and the AC-DC conversion circuits are controlled by a control unit within the power converter 100. Each DC-DC conversion circuit in the power converter 100 is also configured with a corresponding Maximum Power Point Tracking (MPPT) algorithm. The MPPT algorithm adjusts the PWM duty cycle of the switching transistors in the DC-DC conversion circuit, changing the input operating voltage of the DC-DC conversion circuit to track the maximum power point.

[0035] The DC string 200 includes at least one component controller 210. The input terminal of each component controller 210 is connected to a corresponding DC power supply 300 (such as a photovoltaic module PV) to receive DC power output from the DC power supply 300. The DC power supply 300 can be a photovoltaic module string formed by connecting at least one photovoltaic module in series. The output terminals of all component controllers 210 in the DC string 200 are connected in series to their corresponding DC input terminals A. Multiple DC strings 200 can be connected to different DC input terminals A of the power converter 100, forming a multi-parallel string architecture. Each DC input terminal A can be connected to at least one DC string 200; that is, one DC input terminal A can be connected to one DC string 200. One DC input terminal A can also be connected to multiple parallel DC strings 200, such as... Figure 1 and Figure 2 .

[0036] The component controller 210 can be an optimizer or a shutdown device, depending on the specific implementation requirements.

[0037] Please see Figure 3 , Figure 3 This is a schematic diagram of the component controller, which is an optimizer, provided in an embodiment of this application.

[0038] Taking the component controller 210 employing an optimizer as an example, the optimizer may include a DC-DC conversion circuit, such as a boost circuit, a buck circuit, or a buck-boost circuit. In this embodiment, the optimizer includes a buck circuit as an example. The optimizer can be configured with a maximum power point tracking (MPPT) algorithm and input voltage regulation function. The optimizer uses the photovoltaic module as a power source, and its output serves as the voltage support for the input of the power converter 100. Within its own capabilities, the optimizer can control its input voltage to reach any value.

[0039] Please see Figure 4 As shown, Figure 4 This is a closed-loop control architecture diagram of the optimizer provided in the embodiments of this application.

[0040] The optimizer's closed-loop control consists of mode switching, voltage outer loop, current inner loop, voltage feedforward, voltage limiting loop, PWM drive, Buck circuit, etc., and can realize MPPT algorithm and over-temperature voltage reduction closed-loop control.

[0041] In normal MPPT operation mode, the switch is switched to the input voltage setpoint channel. The input voltage setpoint of this channel is generated by the MPPT algorithm built into the optimizer. Those skilled in the art can clearly understand the specific process, so it will not be described in detail here.

[0042] In the over-temperature voltage / current reduction control mode, the switch is switched to the power / current limiting channel to limit the voltage / current range of the MPPT algorithm, so that the voltage or current setpoint is adjusted according to the preset strategy (see the following description for details), instead of directly tracking the maximum power point. The initial value is the voltage setpoint or voltage setpoint of MPPT under normal operation.

[0043] The voltage outer loop includes a subtractor and a PI controller. The positive input of the subtractor is the voltage setpoint output by the mode switching unit, and the negative input is the input voltage actually acquired by the Buck circuit. The voltage deviation is calculated from the two and then sent to the PI controller. The output of the PI controller is the current setpoint, which serves as the control target for the current inner loop.

[0044] The inner current loop includes a subtractor and a PI controller. The positive input of the subtractor is the current setpoint output from the outer voltage loop, and the negative input is the actual output current collected by the Buck circuit. The current deviation calculated from the two is sent to the PI controller. The PI controller outputs the basic control quantity, which is scaled by the gain coefficient k and then sent to the subsequent superposition stage.

[0045] Voltage feedforward first acquires the actual output voltage of the Buck circuit.v o_real Calculate its relationship with the voltage setpoint. v in_ref The ratio, after being adjusted by the 1-k coefficient, is superimposed on the basic control quantity output by the inner current loop to generate the control quantity after feedforward compensation.

[0046] The voltage limiting loop includes a subtractor, a PI controller, feedforward compensation, and a MIN selector. The positive input of the subtractor is the preset upper limit threshold of the Buck circuit output voltage, and the negative input is the actual output voltage collected by the Buck circuit. The voltage deviation calculated from the two is sent to the PI controller. The PI controller outputs a voltage limiting control quantity, which is superimposed with the preset upper limit threshold feedforward compensation and sent together with the main control quantity from the preceding stage to the MIN selector.

[0047] Finally, the final control quantity output by the MIN minimum value selector is sent to the PWM module. The PWM module generates drive pulses with corresponding duty cycles based on the control quantity to control the on / off state of the power switching transistors in the Buck main circuit. At the same time, the actual input voltage, output voltage, and inductor current of the Buck circuit are sampled in real time and fed back to each control loop to form a complete closed-loop control.

[0048] Please see Figure 5 , Figure 5 This is a schematic diagram of the component controller provided in the embodiment of this application, which is a shutdown device.

[0049] Taking component controller 210 with a shutdown device as an example, it has a fast shutdown function and can respond to commands to cut off the power output of its branch. The shutdown device can integrate a switching transistor; its main function is fast shutdown to ensure safety, and it does not have voltage regulation capabilities. Figure 5 The component controller 210 includes a turn-off device for a semiconductor switch S connected in series between the input photovoltaic module and the output terminal. The figure uses a MOSFET as an example of the switch S, but other devices such as GaN FET, GaN HEMT or SiC MOSFET can also be used.

[0050] It should be noted that the component controller 210 may also include a temperature monitoring device, located inside the component controller 210, for collecting the real-time temperature of the component controller 210. The temperature monitoring point can be located near the main heat-generating components (such as MOSFETs and inductors) or on the surface of the heat sink; the specific location is set according to the requirements of the actual implementation scheme. The component controller 210 may also include a control unit. The control unit in the component controller 210 and the control unit in the power converter 100 can communicate with each other, exchanging data via power line carrier communication (PLC) or a wireless communication network. The temperature data collected by the temperature monitoring device can be transmitted to the control unit of the component controller 210 or the control unit of the power converter 100. The control unit within the power converter 100 can be configured with an MLPE (Module-Level Power Electronics) master node for collecting temperature data from each component controller 210 and issuing control commands. The control unit of the component controller 210 can execute local temperature control actions or control commands issued by the power converter 100. It should also be noted that the subsequent temperature control method is executed by the control unit of the component controller 210 and the control unit of the power converter 100. In the specific description, the control unit of the component controller 210 and the control unit of the power converter 100 are directly described as the component controller 210 and the power converter 100.

[0051] Please see Figure 3 The component controller 210 also incorporates a bypass circuit 211. The bypass circuit 211 may include an N-channel MOSFET with low on-resistance as a bypass switch, and a self-driving chip that controls the switching on and off of the bypass switch. The bypass switch and the self-driving chip are connected in parallel at the output port of the component controller 210 and can be controlled in conjunction with the main switch of the component controller 210. The bypass circuit 211 can be used in both optimizers and shutdown circuits.

[0052] When the component controller 210 is operating normally and does not perform a blocking action, the bypass switch of the bypass circuit 211 remains open, and DC power is transmitted through the main power circuit of the component controller 210. When the component controller 210 performs a blocking action and the main switch is turned off, the bypass switch of the bypass circuit 211 switches to the conducting state, providing a low-impedance path for the string current of the DC string 200, so that other normally operating component controllers 210 in the same string can continuously output power, which is beneficial for the entire string to still operate normally when a single component controller 210 performs a blocking action.

[0053] Please see Figure 6 , Figure 6 This is a schematic diagram of the structure of the intelligent monitoring system for photovoltaic power plants provided in the embodiments of this application.

[0054] A photovoltaic power plant intelligent monitoring system using power line carrier communication technology primarily comprises a DC power supply 300 (photovoltaic modules), a module controller 210, a power converter 100, batteries, loads, meters, a power grid 400, communication modules, magnetic rings, power lines, and a solar cloud platform. The MLPE master node in the power converter 100 communicates with the module controller 210 via a PLC (power line carrier) communication system. PLC communication uses power lines as the transmission channel, transmitting analog or digital signals at high speed via carrier waves, making it widely applicable to photovoltaic power plant intelligent monitoring systems. It eliminates the need for rewiring, utilizing power lines for convenient network deployment, short construction periods, low cost, high reliability, and communication speeds that meet system requirements, providing a cost-effective data communication platform for photovoltaic power plant intelligent monitoring systems. Simultaneously, the power converter 100 can wirelessly upload all system operating data to the iSolarCloud (intelligent photovoltaic cloud platform), enabling remote status monitoring, temperature control event alarms, and operation and maintenance management of the power plant via mobile apps and web interfaces.

[0055] Based on the above system structure, this application can effectively cool down the component controller 210 when the component controller 210 experiences abnormal temperature through the coordinated control of the component controller 210 and the power converter 100, while simultaneously improving the operational stability and reliability of the power system. The following provides a detailed description of the temperature control method for a specific power system using the technical solution of this application.

[0056] Please see Figure 7 , Figure 7 This is a schematic flowchart of a temperature control method provided in an embodiment of this application.

[0057] In some embodiments, this application provides a temperature control method for a power system, the temperature control method comprising: Step S101: In response to the temperature of any component controller 210 in the first DC string being higher than the first preset temperature, control the first component controller to block the wave. The first component controller is the component controller 210 in the first DC string whose temperature is higher than the first preset temperature. The first DC string is any DC string 200.

[0058] The first preset temperature can be determined as follows: When the ambient temperature reaches 65℃, the component controller 210 is put into full-load operation. The temperature collected by the temperature monitoring device at the moment when the main heat-generating device (taking MOSFET as an example) in the component controller 210 is at its most intense is the first preset temperature, denoted as T0. This temperature value takes into account the superposition effect of ambient temperature and device heating, and serves as the reference threshold for triggering temperature control protection.

[0059] It's important to understand that for the component controller 210, the main temperature points involved during operation include ambient temperature, the temperature of the main heat-generating components (primarily MOSFETs), and the measurement point temperature. Based on the solution requirements, the optimizer needs to maintain full-load operation when the ambient temperature is below 65°C. In actual optimizer operation, regardless of whether the optimizer's own temperature is stable, the measurement point temperature is always higher than the ambient temperature but lower than the temperature of the main heat-generating components. This temperature relationship is a crucial basis for optimizer temperature control. Therefore, by setting the temperature value T0, the optimizer can achieve voltage reduction operation when the ambient temperature exceeds 65°C, thereby reducing the adverse effects of excessively high temperatures. It should be noted that the specific ambient temperature value is set according to the actual implementation requirements and can also be other values; this is not limited here.

[0060] The process for determining the first component controller is as follows: the component controller 210 whose temperature in the first DC string is higher than the first preset temperature T0 is determined as the first component controller. It should be noted that if multiple component controllers 210 have excessive temperatures at the same time, the subsequent steps can be performed individually or in batches.

[0061] The PWM blocking operation refers to the component controller 210 stopping the output of the PWM drive signal, and the power switching transistors (such as MOSFETs) in the component controller 210 entering the off state. It should be noted that at this time, the bypass circuit 211 in the component controller 210 switches to the on state so that the current of the first DC string can flow through the bypass circuit 211 to maintain the string current path. At the same time, the first component controller stops outputting power, thereby cooling down the individual component controller 210.

[0062] Specifically, in step S101, taking the first DC string as an example, the first DC string contains multiple component controllers 210 connected in series. Under normal operating conditions, each component controller 210 operates in maximum power point tracking mode to ensure the power generation efficiency of the photovoltaic system. It converts the electrical energy output from the photovoltaic modules on its input side and inputs it to the power converter 100 via the DC string 200. The power converter 100 combines the electrical energy from the multiple DC strings 200 and converts it into AC power, which is then fed into the grid 400. During system operation, each component controller 210 monitors its own temperature in real time. When the temperature of any component controller 210 in the first DC string exceeds a first preset temperature, the corresponding component controller 210 acts as the first component controller and controls its own voltage suppression. Additionally, at this time, the first component controller also controls its internal bypass circuit 211 to switch to the conducting state, ensuring that the current path of the DC string 200 remains unobstructed, and other normally operating component controllers 210 in this branch are not affected.

[0063] Step S102: After blocking the first component controller for a first preset time, in response to the temperature of the first component controller being higher than the preset safe temperature, the string current of the first DC string is reduced.

[0064] The first preset duration can be set to 30 minutes; the preset safe temperature can be set to T0-3℃, that is, 3 degrees Celsius lower than the first preset temperature. This temperature difference setting helps to reduce the frequent execution of the temperature control method near the preset safe temperature, providing stable hysteresis characteristics. The above data examples can be set to other data according to the actual implementation plan requirements, and are not limited here.

[0065] String current refers to the operating current in the series circuit of the DC string 200, which is also the output current of the DC string 200, or the current flowing from the DC string 200 into the corresponding DC input terminal A. The reduction of string current can be controlled by the power converter 100. It should be noted that the internal temperature of the component controller 210 is related not only to the ambient temperature but also to the operating current. Since the output current of the component controller 210 is mainly controlled by the power converter 100, the reduction of string current can be coordinated by the power converter 100.

[0066] Specifically, in step S102, if the temperature of the first component controller is still higher than the preset safe temperature after the first component controller has been blocked for a first preset time, it indicates that the individual component blocking cooling effect is insufficient and control needs to be upgraded. At this time, the power converter 100 intervenes to reduce the string current of the first DC string. Reducing the string current of the first DC string means reducing the input current of the DC input terminal A connected to the first DC string, without affecting the current of other strings connected to the parallel DC input terminal A. The power converter 100 can reduce the string current of the first DC string by reducing the input current of the corresponding DC input terminal A.

[0067] For example, taking the component controller 210 including an optimizer as an example, when only one DC string 200 is connected to the first DC input terminal A, the first DC input terminal A is the DC input terminal A connected to the first component controller. The process by which the power converter 100 reduces the input current of the first DC input terminal A is as follows: the power converter 100 reduces the input current setpoint of the corresponding Boost circuit, and through the corresponding MPPT process in the power converter 100, the input current of the first DC input terminal A can be reduced to the input current setpoint. Then, each string controller in the first DC string can use this input current setpoint as the current setpoint of the current inner loop in the MPPT process, so that each string controller in the first DC string can reduce the string current of the first DC string based on its own closed-loop control. When multiple DC strings 200 are connected in parallel to the first DC input terminal A, the power converter 100 reduces the input current of the first DC input terminal A using the method described above. Each DC string 200 connected to the first DC input terminal A will reduce its string current. The sum of the current reduction values ​​of each DC string 200 is the reduction value of the input current of the first DC input terminal A. The specific current reduction value of each DC string 200 is adaptively adjusted according to the performance of each DC string 200 (such as lighting characteristics). Those skilled in the art will clearly understand the specific process, which will not be elaborated here.

[0068] For example, taking the component controller 210 including a shutdown device as an example, the shutdown device has no active voltage regulation function and is only connected to the string as a controllable switch. When only one DC string 200 is connected to the first DC input terminal A, the power converter 100 uses the method described above to reduce the input current of the first DC input terminal A, thereby directly reducing the current flowing through the shutdown device, which can reduce the string current of the first DC string. When multiple DC strings 200 are connected in parallel to the first DC input terminal A, the power converter 100 uses the method described above to reduce the input current of the first DC input terminal A. Then, the string current of each DC string 200 connected to the first DC input terminal A will be reduced, and the current on each DC string is inversely distributed according to the total branch impedance (including the dynamic impedance of the photovoltaic module and the line impedance).

[0069] It should be noted that if the temperature of the first component controller is still higher than the preset safe temperature after the first component controller has been blocked for a first preset time, the first component controller will remain in the blocked state during the process of reducing the string current of the first DC string until the temperature of each component controller 210 in the first DC string is lower than or equal to the preset safe temperature, the string current of the first DC string will be increased, and the first component controller will control itself to generate waves normally.

[0070] As can be seen, after the string current decreases, the output current of all component controllers 210 in the first DC string decreases synchronously, thereby reducing the switching loss and conduction loss of each component controller 210 and achieving overall string cooling.

[0071] Step S103: In response to the temperature of each component controller 210 in the first DC string being lower than or equal to the preset safe temperature, increase the string current of the first DC string.

[0072] Specifically, during the process of reducing the string current of the first DC string, the power converter 100 continuously monitors the temperature of each component controller 210 in the first DC string. When the temperature of each component controller 210 in the first DC string is lower than or equal to the preset safe temperature (T0-3℃), the string current of the first DC string is increased, that is, the power converter 100 increases the input current of the first DC input terminal A. The power converter 100 gradually restores to the normal MPPT operating current, so that the power converter 100 automatically switches to the maximum power point tracking operating mode. At the same time, each component controller 210 also automatically switches to the maximum power point tracking operating mode to ensure the power generation efficiency of the photovoltaic system.

[0073] Through the above technical solution, this application provides a temperature control method for a power system. The method first controls the first component controller in the first DC string whose temperature is higher than a first preset temperature to implement initial cooling. After the blocking time reaches a first preset duration, in response to the temperature of the first component controller being higher than a preset safe temperature, the string current of the first DC string is reduced, thereby further enhancing the cooling effect. When the temperature of each component controller 210 in the first DC string is lower than or equal to the preset safe temperature, the string current of the first DC string is increased, allowing each component controller 210 to return to its normal operating current. This application achieves effective cooling of the component controller 210 through the coordinated action of the blocking of the first component controller and the string current of the first DC string, while simultaneously improving the operational stability and reliability of the power system.

[0074] In some embodiments, reducing the string current of the first DC string includes: reducing the string current of the first DC string by a preset current magnitude every first preset time interval until the temperature of each component controller 210 in the first DC string is lower than or equal to a preset safe temperature, or the string current is reduced to the minimum operating current.

[0075] The first preset time interval can be 3 minutes. The minimum operating current can be 0A or 2A. The preset current reduction range of the string current of the first DC string is determined by the current reduction range of the first DC input terminal A. That is, in each iteration step, by reducing the input current of the first DC input terminal A by the preset current value, the string current of the first DC string is reduced by the preset current range. The initial value of the input current of the first DC input terminal A is the MPPT operating current under normal operation. In each iteration, the preset current reduction value of the input current of the first DC input terminal A is 1% of the current current value, i.e., ΔI = Icurr × 1%, where ΔI represents the preset current reduction value of the input current of the first DC input terminal A, and Icurr represents the current current value. It should be noted that this preset current value has a minimum current change value, which can be 0.05A. That is, when the calculated preset current value is less than or equal to 0.05A, 0.05A is uniformly used as the preset current value for this iteration.

[0076] Specifically, in this embodiment, the power converter 100 first obtains the current input current value of the first DC input terminal A, and then reduces the input current of the first DC input terminal A by a preset current value, that is, obtains a new input current setpoint Itarget = Icurr – ΔI, where Itarget is the current current value for the next iteration. After a first preset time interval, the power converter 100 detects the temperature of each component controller 210 in the first DC string. If the temperature of any component controller 210 is still higher than the preset safe temperature, and the current current value is greater than the minimum operating current, then the input current of the first DC input terminal A is further reduced by the preset value, forming an iterative cycle.

[0077] The iterative adjustment continues until either of the following conditions is met, at which point the iterative process exits: The temperature of the controller 210 of each component in the first DC string is lower than or equal to the preset safe temperature, current limiting stops, and the power converter 100 controls the current at the first DC input terminal A to increase and recover. Alternatively, the current at the first DC input terminal A is less than or equal to the minimum operating current, current reduction stops, and the current is maintained or other protection mechanisms are triggered.

[0078] Understandably, this application embodiment achieves refined closed-loop control of the current through a stepped, small-amplitude current regulation method, solving the technical problems of sudden changes in system power, voltage fluctuations, and inverter instability caused by large-scale current limiting. Furthermore, by setting fixed adjustment intervals and amplitudes, the temperature of the component controller 210 can be steadily reduced, avoiding thermal stress shocks to the devices caused by drastic temperature fluctuations. Simultaneously, it can accurately match cooling requirements, avoiding unnecessary losses in power generation efficiency due to excessive current limiting, further improving the system stability and power generation continuity of the temperature control process.

[0079] In some embodiments, after reducing the string current of the first DC string, the temperature control method further includes: Step S201: After a second preset time period, in response to the temperature of a component controller 210 in the first DC string being higher than a preset safe temperature, control each component controller 210 in the first DC string to go into standby mode.

[0080] Step S202: In response to the temperature of each component controller 210 in the first DC string being lower than or equal to the preset safe temperature, control each component controller 210 in the first DC string to turn on.

[0081] Specifically, after step S102, i.e., after reducing the string current of the first DC string, step S201 is executed to start a second preset timer, which can be set to 30 minutes. If, after the second preset time, the power converter 100 detects that the temperature of a component controller 210 in the first DC string is still higher than a preset safe temperature, it indicates that reducing the string current of the first DC string has failed to effectively control the temperature of that string, thereby triggering the next level of regulation. That is, the power converter 100 sends a standby command to each component controller 210 in the first DC string, and the component controller 210 executes the standby command to enter standby mode, stopping its power output and entering a standby state. At the same time, the bypass circuit 211 can remain on or off according to the system configuration. In addition, the power converter 100 can maintain the normal operation of other DC strings 200 or adjust the overall output power according to the system strategy.

[0082] In the standby state of each component controller 210 in the first DC string, each component controller 210 in the first DC string stops heating and the temperature gradually decreases. When the temperature of each component controller 210 in the first DC string is lower than or equal to the preset safe temperature, step S202 is executed, and the power converter 100 controls each component controller 210 in the first DC string to turn on and restore to the normal MPPT operation mode.

[0083] Understandably, in cases where reducing the string current still fails to effectively cool the string, the embodiments of this application achieve thorough cooling by suspending the entire string in standby mode, while other DC strings 200 can still operate normally and generate electricity, thus not affecting the power generation of the system. This ensures the safety of the faulty string while allowing other normal strings to continue generating electricity and reduces the risk of equipment damage.

[0084] In some embodiments, after reducing the string current of the first DC string, the temperature control method further includes: Step S301: After a second preset time, in response to the fact that the temperature of the component controller 210 in the first DC string is higher than the preset safe temperature, control all component controllers 210 to standby and control the power converter 100 to standby.

[0085] Step S302: When the temperature of all component controllers 210 is lower than or equal to the preset safe temperature, control the power converter 100 to start and control all component controllers 210 to start.

[0086] Specifically, after the second preset time period, if the temperature of the component controller 210 in the first DC string is still higher than the preset safe temperature, step S301 is executed, that is, the power converter 100 sends a standby command to each component controller 210 in all DC strings 200, controls all component controllers 210 to go into standby mode, and the power converter 100 itself enters standby mode and stops power conversion.

[0087] During the standby process of the power converter 100, step S302 is executed. The power converter 100 monitors the temperature of all component controllers 210. When the temperature of all component controllers 210 is lower than or equal to the preset safe temperature, the power converter 100 switches from the standby state to the power-on state. At the same time, the power converter 100 sends a power-on command to all component controllers 210 to restore the normal power generation of the entire system.

[0088] It is important to understand that when the power converter 100 has multiple DC input terminals A, and each DC input terminal A is connected to an independent DC string 200, shutting down only the first DC string while keeping the others running may cause excessive differences in the input voltage of each Boost circuit, resulting in an imbalance in the high-low voltage ratio. This could affect the voltage balance inside the power converter 100, leading to difficulties in controlling the power converter 100 or even abnormal operation. Therefore, a complete restart is necessary to ensure the consistency of the voltage state of each string.

[0089] In some other embodiments, after a second preset time period, in response to the temperature of a component controller 210 within the first DC string exceeding a preset safe temperature, the power converter 100 can control all component controllers 210 connected to the first DC input terminal A to standby for cooling. When the temperature of all component controllers 210 connected to the first DC input terminal A is below or equal to the preset safe temperature, the power converter 100 controls all component controllers 210 connected to the first DC input terminal A to power on. By directly stopping the input to each first DC input terminal A, the overheated DC string 200 cannot affect other DC input terminals A, thereby allowing the power converter 100 to operate normally.

[0090] Understandably, when the high temperature problem in the embodiments of this application may affect the overall safety of the system, the use of a complete system shutdown or the standby of all component controllers 210 corresponding to the first DC input terminal A can ensure the safety of the equipment and help solve the problem of abnormal system operation caused by local voltage mismatch.

[0091] It is important to understand that when the component controller 210 is an optimizer, the circuit model of the optimizer can be regarded as a two-port element, where the voltage Uo, current Io, and equivalent resistance of the output terminal are Ro, and the voltage Ui, current Ii, and equivalent resistance of the input terminal are Ri. Therefore, Ri = Ui / Ii = (Uo / D) / (D*Io) = Uo / (Io*D^2) = Ro / (D^2), where D is the duty cycle value [0, 1], so the range of Ri is [Ri, ∞].

[0092] Furthermore, with a constant load, the output power of the photovoltaic module string connected to the optimizer can be changed by adjusting the optimizer's duty cycle. For example, increasing the duty cycle D shifts the voltage point of the photovoltaic module string to the left, reducing the output power; decreasing the duty cycle D shifts the voltage point of the photovoltaic module string to the right, increasing the output power. However, in actual use, the duty cycle cannot be increased indefinitely, as it is affected by the lower limit of the input voltage (the optimizer's minimum start-up voltage of 12V) and the upper limit of the output voltage (when the power converter 100 is in current-limited mode).

[0093] Please see Figure 8 , Figure 8 This is a schematic diagram of the voltage derating curve of the optimizer provided in this application embodiment at high temperature (65°C). The horizontal axis represents the input voltage of the optimizer, and the vertical axis represents the output power of the photovoltaic module string. As can be seen from the figure, the maximum power point (1028.4W) is reached at Vin≈51.4V, and the power drops again to 1028.4W at Vin≈89.9V, forming a symmetrical power envelope. This curve visually reveals the power-voltage characteristics of the photovoltaic module at high temperatures: there exists an optimal operating voltage range (approximately 51-90V), and deviations from this range towards lower or higher voltages result in a sharp decrease in output power. Furthermore, when the optimizer reduces the input voltage by increasing the Buck duty cycle, the module's operating point shifts to the left along the curve, the output power decreases, and the internal processing power of the optimizer decreases, thereby achieving a reduction in heat generation and temperature control.

[0094] Therefore, when the optimizer's input voltage increases, while the output current remains constant, the optimizer's switching losses increase accordingly, while the conduction losses remain essentially unchanged. This increase in switching losses leads to more heat generation in the optimizer, negating its cooling effect and potentially causing the temperature to rise further. Conversely, when the optimizer's input voltage decreases, with the output current remaining constant, the optimizer's switching losses decrease accordingly, thereby reducing heat generation and lowering the temperature. Thus, it can be concluded that the optimizer can reduce losses and heat generation by increasing the Buck duty cycle, thereby reducing the input voltage.

[0095] In some embodiments, when the component controller 210 is an optimizer, before controlling the first component controller to block the waveform after the temperature of any component controller 210 in the first DC string exceeds a first preset temperature, the temperature control method further includes: Step S401: Reduce the input voltage at the input terminal of the first component controller. It is known that the component controller 210 is an optimizer with voltage reduction capability. Specifically, under normal operating conditions, the optimizer tracks the maximum power point of the photovoltaic module using the MPPT algorithm and uses the voltage of this maximum power point as the setpoint for the input voltage closed-loop control, achieving precise control of the input voltage.

[0096] When the optimizer detects that its own temperature is higher than the first preset temperature, it first executes step S401, which reduces the input voltage. Specifically, the voltage reduction strategy involves the optimizer reducing the voltage setpoint of the input voltage closed-loop control, thereby adjusting the duty cycle of the internal Buck circuit to lower the input voltage. This reduction in input voltage leads to a decrease in the optimizer's switching losses, thus reducing heat generation and achieving cooling.

[0097] In some embodiments, reducing the port input voltage of the first component controller input terminal includes: reducing the port input voltage of the first component controller input terminal by a preset voltage magnitude every first preset time interval until the temperature of the first component controller is lower than or equal to a preset safe temperature, or the port input voltage is reduced to a minimum operating voltage.

[0098] Specifically, in some examples, the port input voltage can be reduced by a preset voltage margin (5V) every first preset time interval (e.g., 90 seconds) until either of the following conditions is met: the temperature of the optimizer is lower than or equal to a preset safe temperature; or the port input voltage is reduced to the minimum operating voltage, which can be set to 20V, to ensure that the auxiliary power supply of the optimizer control circuit does not lose power.

[0099] Please see Figure 9 , Figure 9 This is a schematic diagram of a process for reducing port input voltage according to an embodiment of this application.

[0100] In other examples, when the component controller 210 detects that its own temperature exceeds a first preset temperature T0, it initiates a process to reduce the port input voltage. A timed detection is performed every 90 seconds. If the current temperature of the component controller 210 is higher than T0, the component controller 210 reduces the given value of the port input voltage by 5*2V (minimum operating voltage 20V) from the current value, and uses the updated voltage value as the given value for the outer voltage loop. Through closed-loop control, the actual value of the port input voltage follows suit, thereby reducing switching losses and heat generation. If the current temperature of the component controller 210 is not higher than T0 (the first preset temperature), it further determines whether it is lower than T0-3℃ (the preset safe temperature). If so, it indicates that the temperature has been sufficiently reduced, and the given value of the input voltage is increased by 5*2V (maximum limit 125V) from the current value, gradually restoring it to the maximum power point. If the temperature is between T0-3℃ and T0, the component controller 210 reduces the given value of the port input voltage by 5V from the current value. The final updated voltage value is used as the setpoint for the outer voltage loop. Closed-loop control causes the actual input voltage at the port to decrease accordingly, thereby reducing switching losses and lowering heat generation.

[0101] It should be noted that this application can reduce the preset voltage amplitude based on the temperature of the component controller 210, so that when the temperature is high, the preset voltage amplitude is reduced by a larger amount, thereby accelerating the cooling of the component controller 210.

[0102] Step S402: After reducing the port input voltage of the first component controller for a third preset time, in response to the first component controller being higher than a preset safe temperature, or in response to the first component controller being higher than or equal to a second preset temperature within the third preset time, the first component controller is controlled to block the wave, and the second preset temperature is higher than the first preset temperature.

[0103] Specifically, if the optimizer's temperature fails to drop below the preset safe temperature after a third preset duration (e.g., 30 minutes) of reducing the port input voltage, step S101 is executed, i.e., the optimizer controls itself to shut down. Furthermore, if at any time within the third preset duration, the optimizer detects that its own temperature is higher than or equal to the second preset temperature (e.g., T0+2℃), step S101 is executed, i.e., the optimizer controls itself to shut down. The second preset temperature is higher than the first preset temperature to prevent safety risks caused by excessively rapid temperature increases.

[0104] In some embodiments, after reducing the port input voltage at the input terminal of the first component controller and before controlling the first component controller to block the waveform, the temperature control method further includes: increasing the port input voltage at the input terminal of the first component controller in response to the temperature of the first component controller being lower than or equal to a preset safe temperature.

[0105] Specifically, after reducing the port input voltage of the first component controller, before controlling the first component controller to block the waveform, if the optimizer detects that its own temperature is lower than or equal to the preset safe temperature, it indicates that reducing the port input voltage to control the temperature is effective. Then, when the optimizer temperature is lower than or equal to the preset safe temperature, the optimizer automatically switches back to MPPT operation mode, gradually increases the port input voltage to restore it to the maximum power point voltage, so that the optimizer returns to the normal maximum power generation state to ensure power generation efficiency.

[0106] It should be noted that if the temperature of the first component controller is still higher than the preset safe temperature before controlling the first component controller to block the wave, then after controlling the first component controller to block the wave, the reduction of the port input voltage of the first component controller will stop, and the first component controller will return to the normal MPPT operation mode.

[0107] Understandably, this application embodiment, for optimizers with voltage regulation capabilities, implements progressive temperature control logic through a progressive strategy of first stepping down the voltage and then blocking the waveform. Step-down regulation can maintain a certain power output while cooling down, reducing the impact of premature waveform blocking on power generation.

[0108] It should be noted that when the component controller 210 is a shutdown device, because its core component is a switching transistor, which generates concentrated heat and has no voltage reduction buffer space, the voltage regulation stage is omitted. Since the shutdown device lacks voltage regulation functionality, there is no temperature control process to reduce the input voltage at the shutdown port.

[0109] In some embodiments, the temperature control method further includes: step S501: in response to the number of component controllers 210 with temperatures higher than the first preset temperature exceeding the first threshold, reducing the string current of the second DC string 200, wherein the second DC string 200 is the DC string 200 in which the component controllers 210 with temperatures higher than the first preset temperature are located.

[0110] Step S502: In response to the temperature of each component controller 210 in all second DC strings 200 being lower than or equal to a preset safe temperature, increase the string current of the second DC strings 200.

[0111] Specifically, the power converter 100 continuously counts the number of component controllers 210 in all DC strings 200 whose temperature is higher than a first preset temperature T0. When this number exceeds a first threshold (which can be set to 20% of the total number of component controllers 210), it directly triggers the regulation of reducing the string current. At this time, the power converter 100 reduces the string current of all DC strings 200 containing component controllers 210 with abnormal temperatures, that is, the string current of each second DC string 200. The specific process of reducing the string current can be referred to the previous description, and will not be repeated here. It should be noted that if there is at least one component controller 210 with abnormal temperature in a DC string 200, the current of the DC input terminal A connected to that string is reduced to reduce the string current of that string; if there are no component controllers 210 with abnormal temperature in all DC strings 200 connected to a certain DC input terminal A, the Boost circuit corresponding to the DC input terminal A maintains the normal MPPT operation mode. During the process of reducing the string current of the second DC string 200, when the temperature of each component controller 210 in all the second DC strings 200 with abnormal temperatures drops below the preset safe temperature, the power converter 100 increases the string current of these strings. The specific increase process can be referred to the previous description and will not be repeated here, until normal MPPT operation is restored.

[0112] In some embodiments, the temperature control method further includes: Step S601: In response to the number of component controllers 210 with temperatures higher than the first preset temperature exceeding the second threshold, control all component controllers 210 to standby and control the power converter 100 to standby, the second threshold being greater than the first threshold.

[0113] Step S602: In response to the fact that the temperature of all component controllers 210 is lower than or equal to the preset safe temperature, control the power converter 100 to start and control all component controllers 210 to start.

[0114] Specifically, when the number of component controllers 210300 with temperatures higher than the first preset temperature T0 exceeds the second threshold (which can be set to 50% of the total number of all component controllers 210, and the second threshold is greater than the first threshold), the standby control of the component controllers 210 and the power converter 100 is directly triggered. That is, the power converter 100 controls all component controllers 210 to enter standby mode and also controls itself to enter standby mode. After the temperature of all component controllers 210 drops below the preset safe temperature, the power converter 100 turns on and controls all component controllers 210 to turn on, restoring power generation of the entire system.

[0115] In this embodiment, the first threshold corresponds to an early warning of system-level temperature anomalies. At this time, current limiting control can maintain power generation of some components while ensuring safety. The second threshold corresponds to a systemic high-temperature fault. At this time, the power generation efficiency has been severely damaged, and the system-level standby protection circuit is safe.

[0116] It should be noted that in this embodiment, the control paths of the first and second thresholds coexist with the blocking, reduction of string current, reduction of port input voltage, and standby of some component controllers 210. Whether to trigger the threshold control path depends on the proportion of components with excessive temperature.

[0117] It should also be noted that the embodiments of this application are not limited to the above example of determining whether to trigger the threshold based on the proportion of components exceeding the temperature limit, but may also include the following examples.

[0118] For example, in some examples, the temperature control method further includes: in response to the number of components in the controllers 210 connected to the third DC input terminal A having a temperature higher than a first preset temperature exceeding a first threshold, the power converter 100 reduces the input current of the third DC input terminal A, where the third DC input terminal A is any DC input terminal A.

[0119] In response to the fact that the temperature of each component controller 210 connected to the third DC input terminal A is lower than or equal to the preset safe temperature, the power converter 100 increases the input current of the third DC input terminal A.

[0120] In other examples, the temperature control method further includes: in response to the number of component controllers 210 connected to the third DC input terminal A having a temperature higher than a first preset temperature exceeding a second threshold, the power converter 100 controls all component controllers 210 to standby and controls itself to enter standby state. In response to the fact that the temperature of all component controllers 210 is lower than or equal to the preset safe temperature, the power converter 100 turns on and controls all component controllers 210 to turn on, restoring power generation of the entire system.

[0121] In other embodiments, the temperature control method further includes: in response to the number of component controllers 210 connected to the third DC input terminal A having a temperature higher than a first preset temperature exceeding a second threshold, the power converter 100 controls all component controllers 210 connected to the third DC input terminal A to standby mode. In response to the fact that the temperature of all component controllers 210 is lower than or equal to the preset safe temperature, the power converter 100 controls all component controllers 210 connected to the third DC input terminal A to start up and restore the power generation of the entire system.

[0122] Understandably, by counting the number of component controllers 210 exhibiting abnormal temperatures, the system can assess the severity of the high-temperature problem from a macroscopic perspective and directly switch to the corresponding control. When the proportion of high-temperature components is low, current limiting is prioritized for overall cooling to avoid excessive intervention; when the proportion of high-temperature components is high, the entire system is put into standby mode to control the temperature as quickly as possible and ensure system safety. This solution complements the progressive control based on individual unit temperatures, forming a multi-path, multi-criteria, three-dimensional temperature control system.

[0123] In some embodiments, after controlling the first component controller to block the waveform and before reducing the string current of the first DC string, the temperature control method further includes: controlling the first component controller to generate a waveform normally in response to the temperature of the first component controller being lower than or equal to a preset safe temperature.

[0124] Specifically, after the component controller 210 performs a waveform shutdown, it continuously monitors its own temperature. Before reducing the string current of the first DC string, if the temperature of the first component controller is detected to be lower than or equal to a preset safe temperature, it immediately controls the component controller 210 to resume normal waveform generation (i.e., restart the switching action and output power) without waiting for the first preset time period to end. This recovery operation is performed autonomously by the component controller 210 without the intervention of the power converter 100. At the same time, the component controller 210 restarts the PWM drive, the bypass circuit 211 switches to the open state, and the power current flows through the normal conversion path of the component controller 210, and the component returns to the MPPT maximum power generation state.

[0125] Understandably, this application, with its significant wave-blocking and cooling effect, promptly restores the power output of the component controller 210, minimizing power generation losses. This avoids unnecessary waiting time and improves the system's power generation efficiency.

[0126] In some embodiments, the power system further includes a bypass circuit 211, which corresponds one-to-one with the component controller 210, and the bypass circuit 211 is connected in parallel with the output terminal of the corresponding component controller 210; the temperature control method further includes: in response to the component controller 210 not performing wave blocking, controlling the bypass circuit 211 to remain in an open state; in response to the component controller 210 performing wave blocking, controlling the bypass circuit 211 to switch to an on state.

[0127] It should be noted that the control of the on / off state of the bypass circuit 211 can be referred to the previous description, and will not be repeated here. This application achieves the technical effect of single-unit waveform blocking without affecting the entire string's power generation through the coordinated control of the bypass circuit 211, solving the problem of power loss in the entire string due to the shutdown of a single device. At the same time, the automatic switching of the bypass circuit 211 requires no manual intervention, improving the system's reliability and automation level.

[0128] Please see Figure 10 , Figure 10 This is a schematic flowchart of another temperature control method provided in an embodiment of this application.

[0129] Taking the component controller 210, which includes an optimizer, as an example, the following example illustrates the optimizer's temperature control method. The optimizer's temperature control method consists of four levels, each capable of cooling. If the previous level fails to achieve a cooling effect, it switches to the next level to control the individual unit and system temperatures. The core four-level temperature control derating scheme is shown below: Firstly, in the first stage, temperature control is autonomously executed by the component controller 210. When the temperature of any component controller 210 in the first DC string exceeds the first preset temperature T0, the first component controller initiates a step-down cooling process. Specifically, this reduces switching losses by lowering the input voltage at the input terminal of the first component controller, thus achieving a cooling effect on individual components. When the temperature at the first component controller's measurement point is less than or equal to T0-3℃, the first component controller automatically switches back to maximum power point tracking mode to ensure power generation efficiency. If the first stage of cooling cannot effectively reduce the temperature of the first component controller, the second stage must be initiated. Specific switching conditions include: the temperature of the first component controller fails to drop to T0-3℃ within a specified time threshold (e.g., 30 minutes); or during the first stage of cooling, the temperature of the first component controller rises to greater than or equal to T0+2℃.

[0130] The second-stage temperature control is implemented by component controller 210, which shuts off the waveform. During this time, the first component controller ceases power output to achieve faster individual unit cooling. During the waveform shutdown, bypass circuit 211 is activated to maintain the current path, ensuring the normal operation of other component controllers 210. When the temperature of the first component controller drops below T0-3℃, component controller 210 automatically resumes waveform output and switches back to MPPT mode. If the second-stage temperature control still fails to meet the requirements, the third stage begins. Switching conditions include: the first component controller cannot reduce the temperature to less than or equal to T0-3℃ within 30 minutes of the second-stage temperature control.

[0131] The third-level temperature control is implemented by the power converter 100, which performs system-level current limiting. The power converter 100 reduces the system MPPT level current, i.e., reduces the input current at its input terminal, thereby lowering the string current of the first DC string and achieving a cooling effect. Current limiting uses a step-by-step adjustment method until the temperature of all component controllers 210 in the first DC string drops below T0-3℃. At this point, the power converter 100 restores the target BOOST current limit value for each channel to the default maximum operating current value and automatically switches back to MPPT operation mode. If the third-level temperature control still fails to achieve the target, it proceeds to the fourth level. The switching conditions include: the third-level temperature control fails to reduce the temperature of all component controllers 210 in the first DC string to less than or equal to T0-3℃ within 30 minutes.

[0132] The fourth-stage temperature control is performed by the power converter 100 and the module controller 210 in a coordinated manner to quickly shut down the system. At this time, neither the power converter 100 nor the module controller 210 outputs power, and the system enters a fully shut-down state. After the temperature at the measurement points of all module controllers 210 drops to less than or equal to T0-3℃, the power converter 100 and the module controller 210 are reactivated and automatically switch back to MPPT operation mode for power generation.

[0133] It should be noted that during the execution of the above four-level temperature control process, the number of component controllers 210 whose temperature is higher than the first preset temperature is also continuously monitored simultaneously. If the number of component controllers 210 with a temperature higher than the first preset temperature accounts for more than 20% of the total number of component controllers 210, the power converter 100 reduces the input current at the DC input terminal A. For details, please refer to the previous description, which will not be repeated here. If the number of component controllers 210 with a temperature higher than the first preset temperature accounts for more than 50% of the total number of component controllers 210, the power converter 100 controls all component controllers 210 to standby mode and controls itself to enter standby mode.

[0134] Taking component controller 210 including a shutdown circuit as an example, since it has no voltage regulation function, the first-stage step-down stage is omitted, and the wave blocking shutdown is directly used as the first-stage control. Subsequently, the same three-stage current limiting and four-stage shutdown control as the optimizer scheme are executed. The number of component controllers 210 with temperatures higher than the first preset temperature is monitored synchronously and continuously, and the corresponding temperature control strategy is executed. This will not be elaborated here.

[0135] In summary, in order to achieve a balance between cost and performance, enabling the component controller 210 to operate under power derating at high ambient temperatures and to operate at full load at lower temperatures, embodiments of this application provide a temperature control method for power systems.

[0136] This application addresses the overheating problem of the module controller 210 in a photovoltaic system by proposing a hierarchical, progressive temperature-power coordinated control strategy. By integrating the module controller 210's own MPPT algorithm, input voltage closed-loop control, and system-level coordinated response, it achieves precise cooling while maximizing the photovoltaic system's power generation efficiency. The technical features include a four-level progressive temperature control and derating mechanism: from input voltage regulation and individual module controller 210 shutdown, to current regulation of the power converter 100, and finally to rapid shutdown of both the power converter 100 and the module controller 210, forming a stepped cooling logic from local to system-wide. This achieves effective cooling of the module controller 210, while simultaneously improving the operational stability and reliability of the power system and solving the problem that a single cooling method is insufficient to cope with complex high-temperature scenarios.

[0137] Furthermore, it can ensure both precise cooling and power generation efficiency. Compared with the shutdown or fixed voltage reduction in traditional over-temperature protection (which can easily lead to excessive sacrifice of power generation efficiency), this solution uses threshold control based on T0 (gradually reducing voltage when it is above T0 and automatically restoring MPPT when it is below T0-3℃). While ensuring that the temperature is stable within a safe range (below T0), it minimizes the loss of power generation efficiency and achieves a dynamic balance of cooling without losing efficiency, thus ensuring both precise cooling and power generation efficiency.

[0138] It can also respond in stages to adapt to complex high-temperature scenarios. In response to the problem that traditional single cooling methods (such as only shutting off or only reducing voltage) are difficult to deal with different scenarios such as local high temperature and system-level high temperature, the four-level progressive temperature control mechanism gradually upgrades the response intensity from the individual component controller 210 to the system-level inverter. When there is local high temperature, the impact is reduced by reducing voltage fine-tuning (level 1). When there is global high temperature, the system is shut down (level 4) to ensure safety. It takes into account both local protection and system stability, and responds in stages to adapt to complex high-temperature scenarios.

[0139] Furthermore, traditional over-temperature protection often relies on vague temperature thresholds (such as "shutdown upon exceeding a certain temperature"), which are prone to false triggering or delayed response. This solution achieves precise triggering of each cooling mode by quantifying switching conditions (time threshold of half an hour, temperature difference ±3℃, component ratio of 20% / 50%, etc.), avoiding efficiency loss due to premature protection upgrades or equipment risks caused by delayed upgrades, thus improving the reliability of system operation. The accuracy and reliability of graded triggering ensure the scientific nature of temperature control decisions.

[0140] Moreover, from automatic voltage reduction when the temperature exceeds the limit, to automatic switching of MPPT mode after the temperature recovers, and automatic upgrade / downgrade of protection at all levels, no manual operation is required throughout the entire process. This solves the problem of manual reset or adjustment after overheating in traditional systems, reduces operation and maintenance costs, and is especially suitable for unattended scenarios of large-scale photovoltaic arrays. Automated closed-loop control reduces human intervention.

[0141] In addition, by using stepped cooling methods such as voltage reduction, wave blocking, current limiting, and shutdown, the aging or damage of core components such as MOSFETs caused by continuous high temperatures is avoided. At the same time, a protection threshold of 20V minimum input voltage is set to prevent system abnormalities caused by auxiliary power failure, which significantly improves the service life and operational safety of the equipment.

[0142] Those skilled in the art should understand that the above-described specific embodiments can be combined or modified according to actual application scenarios. For example, for a system that includes a hybrid access of component controller 210 and a shutdown device, different control paths can be adopted for different device types. Furthermore, time parameters such as the first preset duration, second preset duration, third preset duration, and first preset time interval, as well as temperature parameters such as the first preset temperature, preset safe temperature, and second preset temperature, can be adaptively adjusted according to equipment specifications, application environment, and engineering experience; this application does not impose specific limitations in this regard.

[0143] In the above embodiments, the description of each embodiment has its own emphasis. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0144] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A temperature control method of a power system, characterized by, The power system includes a power converter (100) and a DC string (200). The power converter (100) has at least one DC input terminal (A). Each DC input terminal (A) is connected to a corresponding DC string (200). The DC string (200) includes at least one component controller (210). The input terminal of each component controller (210) is used to connect to a corresponding DC power supply (300). The output terminals of all component controllers (210) in the DC string (200) are connected in series to the corresponding DC input terminal (A). The AC output terminal (B) of the power converter (100) is used to connect to the power grid (400). The temperature control method includes: In response to the temperature of any component controller (210) in the first DC string being higher than the first preset temperature, the first component controller is controlled to block the wave. The first component controller is the component controller (210) in the first DC string whose temperature is higher than the first preset temperature. The first DC string is any of the DC strings (200). After the first component controller is blocked for a first preset time, in response to the temperature of the first component controller being higher than the preset safe temperature, the string current of the first DC string is reduced. In response to the temperature of each component controller (210) in the first DC string being lower than or equal to the preset safe temperature, the string current of the first DC string is increased.

2. The temperature control method of a power system according to claim 1, characterized by, The reduction of the string current of the first DC string includes: Every first preset time interval, the string current of the first DC string is reduced by a preset current magnitude until the temperature of each component controller (210) in the first DC string is lower than or equal to the preset safe temperature, or the string current is reduced to the minimum operating current.

3. The temperature control method of a power system according to claim 1, characterized by, After reducing the string current of the first DC string, the temperature control method further includes: After a second preset time period, in response to the temperature of the component controller (210) in the first DC string being higher than the preset safe temperature, each component controller (210) in the first DC string is controlled to standby. In response to the temperature of each component controller (210) in the first DC string being lower than or equal to the preset safe temperature, the controller (210) in the first DC string is powered on.

4. The temperature control method of a power system according to claim 1, characterized by, After reducing the string current of the first DC string, the temperature control method further includes: After a second preset time period, in response to the temperature of the component controller (210) in the first DC string being higher than the preset safe temperature, all component controllers (210) are controlled to standby and the power converter (100) is controlled to standby. When the temperature of all the component controllers (210) is lower than or equal to the preset safe temperature, the power converter (100) is powered on and all the component controllers (210) are powered on.

5. The temperature control method of a power system according to claim 1, wherein When the component controller (210) is an optimizer, before controlling the first component controller to block the waveform after the temperature of any component controller (210) in the first DC string exceeds a first preset temperature, the temperature control method further includes: Reduce the port input voltage at the controller input terminal of the first component; After reducing the port input voltage of the first component controller for a third preset time, in response to the first component controller being higher than the preset safe temperature, or in response to the first component controller being higher than or equal to the second preset temperature within the third preset time, the first component controller is controlled to block the wave, wherein the second preset temperature is higher than the first preset temperature.

6. The temperature control method for a power system according to claim 5, characterized in that, The reduction of the port input voltage at the input terminal of the first component controller includes: Every first preset time interval, the port input voltage of the first component controller is reduced by a preset voltage magnitude until the temperature of the first component controller is lower than or equal to the preset safe temperature, or the port input voltage is reduced to the minimum operating voltage.

7. The temperature control method for a power system according to claim 5, characterized in that, After reducing the port input voltage at the input terminal of the first component controller and before controlling the first component controller to block the waveform, the temperature control method further includes: In response to the temperature of the first component controller being lower than or equal to the preset safe temperature, the port input voltage at the input terminal of the first component controller is increased.

8. The temperature control method for a power system according to claim 1, characterized in that, The temperature control method also includes: In response to the number of component controllers (210) with temperatures higher than the first preset temperature exceeding a first threshold, the string current of the second DC string (200) is reduced. The second DC string (200) is the DC string (200) in which the component controllers (210) with temperatures higher than the first preset temperature are located. In response to the temperature of each component controller (210) in all the second DC strings (200) being lower than or equal to the preset safe temperature, the string current of the second DC strings (200) is increased.

9. The temperature control method for a power system according to claim 8, characterized in that, The temperature control method also includes: In response to the number of component controllers (210) whose temperature is higher than the first preset temperature exceeding a second threshold, all component controllers (210) are controlled to standby and the power converter (100) is controlled to standby, wherein the second threshold is greater than the first threshold; In response to the fact that the temperature of all the component controllers (210) is lower than or equal to the preset safe temperature, the power converter (100) is powered on and all the component controllers (210) are powered on.

10. The temperature control method for a power system according to claim 1, characterized in that, After the control of the first component controller's blocking, and before the reduction of the string current of the first DC string, the temperature control method further includes: In response to the first component controller's temperature being lower than or equal to the preset safe temperature, the first component controller is controlled to generate waves normally.

11. The temperature control method for a power system according to claim 1, characterized in that, The component controller (210) further includes a bypass circuit (211), and the temperature control method further includes: In response to the component controller (210) not performing wave blocking, the bypass circuit (211) is controlled to remain in the open state; In response to the component controller (210) blocking the wave, the bypass circuit (211) is controlled to switch to the on state.

12. An electric power system, characterized in that, The method for temperature control as described in any one of claims 1 to 11 includes: A power converter (100) and a DC string (200) are provided. The power converter (100) has at least one DC input terminal (A), each of which is connected to a corresponding DC string (200). The DC string (200) includes at least one component controller (210). The input terminal of each component controller (210) is used to connect to a corresponding DC power supply (300). The output terminals of all the component controllers (210) in the DC string (200) are connected in series to the corresponding DC input terminal (A). The AC output terminal (B) of the power converter (100) is used to connect to the power grid (400). The first component controller is configured to control the first component controller to block the wave in response to the temperature of any component controller (210) in the first DC string being higher than the first preset temperature. The first component controller is the component controller (210) in the first DC string whose temperature is higher than the first preset temperature. The first DC string is any of the DC strings (200). The power converter (100) is configured to, after blocking the first component controller for a first preset duration, reduce the string current of the first DC string in response to the temperature of the first component controller being higher than a preset safe temperature; and increase the string current of the first DC string in response to the temperature of each component controller (210) in the first DC string being lower than or equal to the preset safe temperature.

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