Method and apparatus for determining voltage protection threshold, and power conversion device

Abstract

This application discloses a method, apparatus, and power conversion device for determining a voltage protection threshold, belonging to the field of power electronics technology. The method for determining the voltage protection threshold includes: acquiring the temperature of each switching device in the power conversion device; and, when the temperature of at least one of the switching devices is greater than a temperature threshold, determining a voltage protection threshold for the DC bus in the power conversion device based on the temperature of each of the switching devices. The method, apparatus, and power conversion device disclosed in this application dynamically determine the voltage protection threshold for the DC bus in the power conversion device based on the temperature of each switching device when the temperature of at least one switching device in the power conversion device is greater than a temperature threshold, thus balancing inverter utilization and safety.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and in particular relates to a method, device and inverter system for determining voltage protection threshold. Background Technology

[0002] In related technologies, an inverter is a power electronic device that converts direct current (DC) into alternating current (AC), and is widely used in photovoltaic power generation, uninterruptible power supplies (UPS), and motor drives. The core power devices in power conversion devices such as inverters are switching devices such as transistors, and the reliability of these core power devices directly determines the performance and lifespan of the entire power conversion device.

[0003] Currently, power conversion devices typically include overvoltage protection. Overvoltage protection refers to triggering protective actions (such as shutdown or derating) when the DC bus voltage exceeds a fixed protection threshold to prevent the core power components from being damaged by overvoltage. However, this method has drawbacks, such as difficulty in balancing inverter utilization and safety. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method, apparatus, and inverter system for determining the voltage protection threshold, which can balance the utilization rate and safety of the inverter in determining the voltage protection threshold of the DC bus in the power conversion device.

[0005] In a first aspect, this application provides a method for determining a voltage protection threshold, the method comprising: Obtain the temperature of each switching device in the power conversion device; If the temperature of at least one of the switching devices is greater than a temperature threshold, a voltage protection threshold for the DC bus in the power conversion device is determined based on the temperature of each of the switching devices.

[0006] According to the voltage protection threshold determination method of this application, when the temperature of at least one switching device in the power conversion device is greater than the temperature threshold, the voltage protection threshold of the DC bus in the power conversion device is dynamically determined based on the temperature of each switching device, which can take into account both the utilization rate and safety of the inverter.

[0007] According to one embodiment of this application, determining the voltage protection threshold of the DC bus in the power conversion device based on the temperature of each of the switching devices includes: The voltage protection threshold is determined based on the temperature of each of the switching devices, the reference temperature, and the reference threshold corresponding to the reference temperature.

[0008] According to one embodiment of this application, determining the voltage protection threshold based on the temperature of each of the switching devices, a reference temperature, and a reference threshold corresponding to the reference temperature includes: The target temperature difference is obtained based on the temperature of each of the switching devices and the reference temperature; The voltage protection threshold is determined based on the reference threshold and the target temperature difference.

[0009] According to one embodiment of this application, determining the voltage protection threshold based on the reference threshold and the target temperature difference includes: Obtain the product of the target temperature difference and the derating factor; the derating factor is used to indicate the rate of change of the withstand voltage of the switching device with temperature. The difference between the reference threshold and the product is obtained as the voltage protection threshold.

[0010] According to one embodiment of this application, obtaining the target temperature difference based on the temperature of each of the switching devices and the reference temperature includes: The temperature difference between the temperature of each of the switching devices and the reference temperature is obtained respectively; The target temperature difference is obtained based on each of the aforementioned temperature differences.

[0011] According to one embodiment of this application, obtaining the target temperature difference based on each of the temperature differences includes: The maximum, average, median, or weighted average of each of the aforementioned temperature differences is determined as the target temperature difference.

[0012] Secondly, this application provides a device for determining a voltage protection threshold, the device comprising: Temperature acquisition module, used to acquire the temperature of each switching device in the power conversion device; A threshold determination module is used to determine a voltage protection threshold for the DC bus in the power conversion device based on the temperature of each of the switching devices when the temperature of at least one of the switching devices is greater than a temperature threshold.

[0013] According to the voltage protection threshold determination device of this application, when the temperature of at least one switching device in the power conversion device is greater than a temperature threshold, the voltage protection threshold of the DC bus in the power conversion device is dynamically determined based on the temperature of each switching device, which can take into account both the utilization rate and safety of the inverter.

[0014] Thirdly, this application provides a power conversion system, including a power conversion device and a voltage protection threshold determination device as described in the second aspect above.

[0015] According to the power conversion system of this application, when the temperature of at least one switching device in the power conversion device is greater than the temperature threshold, the voltage protection threshold of the DC bus in the power conversion device is dynamically determined based on the temperature of each switching device, which can take into account both the utilization rate and safety of the inverter.

[0016] Fourthly, this application provides a power conversion device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method for determining the voltage protection threshold as described in the first aspect above.

[0017] Fifthly, this application provides a non-volatile computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for determining the voltage protection threshold as described in the first aspect above.

[0018] In a sixth aspect, this application provides a chip including a processor and a communication interface, the communication interface being coupled to the processor, the processor being used to run programs or instructions to implement the method for determining the voltage protection threshold as described in the first aspect.

[0019] In a seventh aspect, this application provides a computer program product, including a computer program that, when executed by a processor, implements the method for determining the voltage protection threshold as described in the first aspect above.

[0020] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is one of the flowcharts illustrating the method for determining the voltage protection threshold provided in the embodiments of this application; Figure 2 This is a second schematic flowchart of the method for determining the voltage protection threshold provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the voltage protection threshold determination device provided in the embodiments of this application; Figure 4 This is a schematic diagram of the power conversion system provided in the embodiments of this application; Figure 5 This is a schematic diagram of the power conversion device provided in the embodiments of this application. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0023] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0024] The following description, in conjunction with the accompanying drawings, details the voltage protection threshold determination method, voltage protection threshold determination device, power conversion system, power conversion device, and readable storage medium provided in this application, through specific embodiments and application scenarios.

[0025] The method for determining the voltage protection threshold can be applied to the terminal, and can be executed by the hardware or software in the terminal.

[0026] The voltage protection threshold determination method provided in this application embodiment can be executed by an electronic device or a functional module or functional entity in an electronic device that can implement the voltage protection threshold determination method. The electronic devices mentioned in this application embodiment include, but are not limited to, mobile phones, tablets, computers, cameras, and wearable devices. The voltage protection threshold determination method provided in this application embodiment will be described below using an electronic device as the execution subject as an example.

[0027] like Figure 1 As shown, the method for determining the voltage protection threshold includes steps 110 and 120.

[0028] In practical implementation, the voltage protection threshold determination method provided in this application embodiment can be applied to a power converter. By determining the voltage protection threshold Vth of the DC bus in the power converter, when the voltage of the DC bus in the power converter exceeds the voltage protection threshold Vth, the power converter is triggered to perform overvoltage protection action to protect the switching devices in the power converter and prevent the switching devices from being damaged by overvoltage. It is understood that the power converter may include at least one switching device.

[0029] In some embodiments, the power conversion device described above may be a DC-AC conversion device (inverter) including at least one switching device, an AC-DC conversion device, a DC-DC conversion device, or an AC-AC conversion device, etc.

[0030] In some embodiments, the switching device described above may be a diode, transistor, field-effect transistor (e.g., junction field-effect transistor or metal-oxide-semiconductor field-effect transistor), or insulated-gate bipolar transistor (IGBT), etc. This application does not specifically limit the type of the switching device described above.

[0031] Step 110: Obtain the temperature of each switching device in the power conversion device.

[0032] In actual operation, the temperature Tc of each switching device in the power conversion device can be obtained separately. It can be understood that the temperature Tc of the switching device can be the actual junction temperature of the PN junction within the switching device.

[0033] In some embodiments, for each switching device, the temperature Tc of the switching device can be obtained by at least one of the following methods: calculation estimation, indirect electrical parameter method, non-contact measurement method, and contact measurement method.

[0034] In some embodiments, the calculation estimation method may include at least one of steady-state calculation based on ambient temperature, dynamic calculation based on transient thermal resistance, and calculation based on case temperature. The aforementioned steady-state calculation based on ambient temperature, dynamic calculation based on transient thermal resistance, and calculation based on case temperature estimate the junction temperature of the PN junction in the switching device based on the ambient temperature, transient thermal resistance, and case temperature of the switching device, respectively, and use the estimation result as the temperature Tc of the switching device.

[0035] For example, for each switching device, the temperature of the heat sink (connected to the housing) of the switching device can be sampled in real time by a temperature sensor and used as the temperature Tc of the switching device.

[0036] In some embodiments, the indirect method for electrical parameters may include at least one of the following: temperature-sensitive parameter calibration method and dedicated transistor thermometer method.

[0037] For example, for each type of transistor switching device, the temperature Tc of the switching device can be obtained by using the mapping relationship between the base-emitter voltage Vbe and the junction temperature of the transistor, and by obtaining the base-emitter voltage Vbe of the switching device and the above mapping relationship.

[0038] In some embodiments, non-contact measurement methods may include at least one of infrared thermometry and the like.

[0039] In some embodiments, the contact measurement method involves directly attaching a miniature sensor to the surface of a switching device to obtain the temperature Tc of the switching device. The aforementioned miniature sensor can be a thermocouple-based sensor or a thermistor-based sensor, etc. This application does not specifically limit the type of miniature sensor used.

[0040] Step 120: When the temperature of at least one switching device is greater than the temperature threshold, determine the voltage protection threshold of the DC bus in the power conversion device based on the temperature of each switching device.

[0041] In actual operation, after obtaining the temperature of each switching device in the power conversion device, it can be determined whether the temperature Tc of any switching device is greater than the temperature threshold T_limit.

[0042] It should be noted that the temperature threshold T_limit can be determined based on the actual conditions such as the electrical parameters of the switching devices in the power conversion device. This application does not limit the specific value of the temperature threshold T_limit.

[0043] In some embodiments, when the temperature Tc of all switching devices in the power conversion device is less than or equal to the temperature threshold T_limit, the voltage protection threshold Vth of the DC bus in the power conversion device can be the default value Vth_default.

[0044] In some embodiments, the default value Vth_default can be the upper limit of the withstand voltage of the switching device (which may be simply referred to as "withstand voltage") set based on normal room temperature (e.g., 20°C to 30°C) or other conditions.

[0045] In some embodiments, if the temperature Tc of any switching device in the power conversion device is greater than the temperature threshold T_limit, the voltage protection threshold Vth of the DC bus in the power conversion device can be dynamically determined based on the temperature Tc of each switching device.

[0046] For example, based on the aforementioned default value Vth_default, and considering the temperature Tc of each switching device, a value lower than the default value Vth_default can be determined as the voltage protection threshold Vth. The difference between the default value Vth_default and the voltage protection threshold Vth can be determined based on the temperature Tc of each switching device. Typically, this difference is positively correlated with the temperature Tc of each switching device.

[0047] In some embodiments, in the mechanism described above for dynamically determining the voltage protection threshold Vth of the DC bus in the power conversion device based on the temperature Tc of each switching device, the voltage protection threshold Vth is negatively correlated with the temperature Tc of each switching device. That is, the higher the temperature Tc of each switching device, the smaller the voltage protection threshold Vth, and vice versa.

[0048] In some embodiments, the temperature Tc of each switching device can be input into a pre-obtained model to obtain the voltage protection threshold Vth output by the model.

[0049] It should be noted that this model can be used to indicate the correspondence between the temperature Tc of each switching device and the voltage protection threshold Vth.

[0050] In some embodiments, the model can be an artificial intelligence model trained on sample data, or it can be other models.

[0051] In some embodiments, the voltage protection threshold Vth of the DC bus in the power conversion device can be dynamically determined based on the temperature Tc of each switching device in the power conversion device whose temperature is greater than the temperature threshold T_limit.

[0052] It should be noted that by determining the DC bus voltage protection threshold Vth in the power conversion device based on the temperature Tc of any switching device in the device when the temperature Tc of any switching device is greater than the temperature threshold T_limit, the DC bus voltage protection threshold Vth can be dynamically reduced as the temperature Tc of the switching device increases. This ensures that the voltage protection threshold Vth is always lower than the upper limit of the actual withstand voltage of the switching device at the current temperature Tc under any operating temperature, achieving precise protection while taking into account both the utilization rate and safety of the inverter.

[0053] It should be noted that switching devices primarily withstand two types of stress during operation: current stress and voltage stress. The voltage stress experienced by switching devices in power conversion devices is directly related to the DC bus voltage Vdc. The maximum voltage stress a switching device can withstand is not a fixed value but decreases significantly as its junction temperature increases. For example, taking an insulated-gate bipolar transistor (IGBT) with a nominal withstand voltage of 600V as the switching device, at a normal junction temperature of 25°C, this IGBT may be able to safely turn off at 750V. However, when its temperature rises to 125°C, its actual withstand voltage limit may drop to 550V or lower.

[0054] In related technologies, the voltage protection threshold Vth is generally determined based on the upper limit of the theoretical withstand voltage of the switching device at its ambient temperature (e.g., 25°C) or maximum junction temperature, with a certain margin. The above-mentioned determination method in related technologies has at least two significant drawbacks. First, the determined voltage protection threshold Vth is too conservative, usually too low. When the switching device temperature is low, the power conversion device, which could normally operate safely at a higher bus voltage, may prematurely trigger overvoltage protection due to the excessively low voltage protection threshold Vth, reducing the utilization rate of the power conversion device. Second, the determined voltage protection threshold Vth is too high, resulting in insufficient protection capability. When the switching device temperature rises due to overload or poor heat dissipation, the actual upper limit of the switching device's withstand voltage may be lower than the fixed voltage protection threshold Vth. Even if the bus voltage does not exceed the fixed voltage protection threshold Vth, it may have already exceeded the upper limit of the actual withstand voltage of the switching device at high temperatures, leading to damage to the switching device due to overstress, reducing the safety and reliability of the power conversion device.

[0055] The voltage protection threshold determination method provided in this application dynamically determines the voltage protection threshold Vth of the DC bus in the power conversion device based on the temperature of the switching device. The determined voltage protection threshold Vth matches the upper limit of the actual withstand voltage of the switching device at its actual temperature, that is, it is neither too high nor too low, thereby taking into account both the utilization rate and safety of the inverter.

[0056] First, by linking the voltage protection threshold Vth of the DC bus with the temperature of the switching device, it can be ensured that the voltage protection threshold Vth is lower than the upper limit of the actual withstand voltage of the switching device at any operating temperature. This can fundamentally reduce or even avoid the risk of the switching device being damaged by voltage overstress at high temperatures, and can greatly improve the reliability and lifespan of the power conversion device.

[0057] Secondly, when the switching devices are at low temperatures, the power conversion device can operate normally at a higher bus voltage, avoiding premature overvoltage protection activation due to an excessively low fixed voltage protection threshold Vth. This allows for full utilization of the switching devices' performance potential and improves the overall efficiency of the power conversion device. For example, in the case of a photovoltaic inverter, the voltage protection threshold determination method provided in this application can increase the power generation of the photovoltaic inverter during dawn and dusk.

[0058] Third, the voltage protection threshold determination method provided in this application embodiment can automatically adapt to different working environments and load conditions of the power conversion device. Whether it is due to changes in the ambient temperature of the power conversion device, long-term full-load operation, or temperature rise caused by the performance degradation of the heat dissipation system, it can provide matching and accurate protection.

[0059] According to the voltage protection threshold determination method provided in the embodiments of this application, when the temperature of at least one switching device in the power conversion device is greater than the temperature threshold, the voltage protection threshold of the DC bus in the power conversion device is dynamically determined based on the temperature of each switching device, which can take into account both the utilization rate and safety of the inverter.

[0060] In some embodiments of this application, the voltage protection threshold of the DC bus in the power conversion device is determined based on the temperature of each switching device, including: determining the voltage protection threshold based on the temperature of each switching device, a reference temperature, and a reference threshold corresponding to the reference temperature.

[0061] In actual implementation, the reference temperature Tb and the reference threshold Vth_base corresponding to the reference temperature Tb can be used as a reference, and the voltage protection threshold Vth of the DC bus in the power conversion device can be dynamically determined in combination with the temperature Tc of each switching device in the power conversion device.

[0062] It should be noted that the reference temperature Tb can be a predetermined temperature, such as room temperature (25°C). The specific value of the reference temperature Tb is not limited in this application. The reference threshold Vth_base corresponding to the reference temperature Tb can be the upper limit of the voltage that the switching device can withstand at that reference temperature Tb.

[0063] In some embodiments, when the reference temperature Tb is a low temperature (e.g., room temperature 20°C or 25°C), the reference threshold Vth_base corresponding to the reference temperature Tb can be used as the aforementioned default value Vth_default.

[0064] In some embodiments, a voltage protection threshold Vth can be determined based on the reference threshold Vth_base corresponding to the reference temperature Tb, combined with the difference between the temperature Tc of each switching device and the reference temperature Tb. The difference between the reference threshold Vth_base corresponding to the reference temperature Tb and the voltage protection threshold Vth can be determined based on the difference between the reference temperature Tb and the temperature Tc of each switching device.

[0065] In some embodiments, the voltage protection threshold Vth of the DC bus in the power conversion device can be dynamically determined based on the temperature Tc of each switching device whose temperature is greater than the temperature threshold T_limit, the reference temperature Tb, and the reference threshold Vth_base corresponding to the reference temperature Tb.

[0066] According to the voltage protection threshold determination method provided in the embodiments of this application, the voltage protection threshold of the DC bus in the power conversion device is dynamically determined based on the temperature of each switching device, the reference temperature, and the reference threshold corresponding to the reference temperature, which can take into account both the utilization rate and safety of the inverter.

[0067] In some embodiments of this application, the voltage protection threshold is determined based on the temperature of each switching device, the reference temperature, and the reference threshold corresponding to the reference temperature, including: obtaining the target temperature difference based on the temperature of each switching device and the reference temperature.

[0068] In actual implementation, a temperature difference can be obtained based on the temperature Tc of each switching device and the reference temperature Tb, which characterizes the degree of difference between the temperature Tc of each switching device and the reference temperature Tb, and is denoted as the target temperature difference.

[0069] The voltage protection threshold is determined based on the reference threshold and the target temperature difference.

[0070] In actual implementation, the voltage protection threshold Vth can be determined by adjusting the base threshold Vth_base corresponding to the base temperature Tb according to the target temperature difference.

[0071] In some embodiments, the reference threshold Vth_base corresponding to the reference temperature Tb and the target temperature difference can be input into a pre-obtained model to obtain the voltage protection threshold Vth output by the model.

[0072] It should be noted that this model can be used to indicate the correspondence between the voltage protection threshold Vth and the reference threshold Vth_base corresponding to the reference temperature Tb, and the target temperature difference.

[0073] In some embodiments, the model can be an artificial intelligence model trained on sample data, or it can be a mathematical model obtained by fitting experimental data.

[0074] According to the voltage protection threshold determination method provided in the embodiments of this application, the target temperature difference is obtained based on the temperature of each switching device and the reference temperature, and the voltage protection threshold is determined based on the reference threshold and the target temperature difference. This method can dynamically determine the voltage protection threshold of the DC bus in the power conversion device, and can take into account both the utilization rate and safety of the inverter.

[0075] In some embodiments of this application, determining a voltage protection threshold based on a reference threshold and a target temperature difference includes: obtaining the product of the target temperature difference and a derating factor; the derating factor is used to indicate the rate of change of the withstand voltage of the switching device with temperature; and obtaining the difference between the reference threshold and the product as the voltage protection threshold.

[0076] In actual implementation, the voltage protection threshold Vth of the DC bus can be calculated using the following formula: Vth=Vth_base-k ΔT.

[0077] Where Tb represents the reference temperature; Vth_base represents the reference threshold corresponding to the reference temperature Tb; k represents the derating factor, which can be in units such as kilovolts per degree Celsius (kV / ℃); and ΔT represents the target temperature difference.

[0078] It should be noted that the derating factor can indicate the rate of change of the withstand voltage of a switching device with temperature.

[0079] For example, the reference temperature Tb is 25°C, and the reference threshold Vth_base corresponding to the reference temperature Tb is the aforementioned default value Vth_default. When only one switching device in the power conversion device has a temperature Tc greater than the temperature threshold T_limit, the voltage protection threshold Vth of the DC bus can be calculated by the following formula: Vth=Vth_base-k (Tc-25).

[0080] It should be noted that Tc in this formula refers to the temperature Tc of a switching device whose temperature is greater than the temperature threshold T_limit. Therefore, the target temperature difference ΔT can be equal to the difference between the temperature Tc of the switching device and 25 (in °C).

[0081] According to the voltage protection threshold determination method provided in the embodiments of this application, the voltage protection threshold can be dynamically determined by obtaining the difference between the reference threshold corresponding to the reference temperature and the product of the target temperature difference and the derating factor, which can take into account both the utilization rate and safety of the inverter.

[0082] In some embodiments of this application, the target temperature difference is obtained based on the temperature of each switching device and a reference temperature, including: obtaining the temperature difference between the temperature of each switching device and the reference temperature.

[0083] In actual operation, the temperature difference between the temperature Tc of each switching device in the power conversion device and the reference temperature Tb can be obtained.

[0084] Based on the temperature differences, the target temperature difference is obtained.

[0085] In actual execution, after obtaining the temperature difference between the temperature Tc of each switching device in the power conversion device and the reference temperature Tb, mathematical statistical analysis can be performed based on each temperature difference to obtain a temperature difference that characterizes the degree of difference between the temperature Tc of each switching device and the reference temperature Tb, which is denoted as the target temperature difference.

[0086] In some embodiments, the target temperature difference can be obtained by performing mathematical statistical analysis based on the temperature difference between the temperature Tc of each switching device whose temperature is greater than the temperature threshold T_limit and the reference temperature Tb in all switching devices of the power conversion device.

[0087] According to the voltage protection threshold determination method provided in the embodiments of this application, by obtaining the target temperature difference based on the temperature difference between the temperature of each switching device in the power conversion device and the reference temperature, a more suitable voltage protection threshold can be determined based on the target temperature difference. The determined voltage protection threshold can take into account both the utilization rate and safety of the inverter.

[0088] In some embodiments of this application, obtaining a target temperature difference based on each temperature difference includes: determining the maximum value, average value, median, or weighted average value among each temperature difference as the target temperature difference.

[0089] In actual implementation, the maximum, average, median, or weighted average of the temperature difference between the temperature Tc of each switching device in the power conversion device and the reference temperature Tb can be obtained as the target temperature difference.

[0090] For example, the maximum value of the temperature difference between the temperature Tc of each switching device in the power conversion device and the reference temperature Tb can be obtained, which improves safety.

[0091] In some embodiments, the maximum, average, median, or weighted average of the temperature differences between the temperature Tc of each switching device in the power conversion device whose temperature is greater than the temperature threshold T_limit and the reference temperature Tb can be obtained as the target temperature difference.

[0092] For example, it is possible to obtain the maximum value of the temperature difference between the temperature Tc of each switching device in the power conversion device that has a temperature greater than the temperature threshold T_limit and the reference temperature Tb, which provides higher safety.

[0093] In some embodiments, when obtaining a weighted average, the weights can be determined based on factors such as the type of switching device, derating factor, and importance.

[0094] According to the voltage protection threshold determination method provided in the embodiments of this application, the maximum, average, median or weighted average of the temperature difference between the temperature of each switching device in the power conversion device and the reference temperature is determined as the target temperature difference. A more suitable voltage protection threshold can be determined based on the target temperature difference, and the determined voltage protection threshold can take into account both the utilization rate and safety of the inverter.

[0095] To facilitate understanding of the above embodiments of this application, the following description is provided in conjunction with... Figure 2 The method for determining the voltage protection threshold and the overvoltage protection process based thereon are described. In some embodiments, reference is made to... Figure 2 The implementation process of determining the voltage protection threshold may include the following steps.

[0096] Step 210: Load the default values ​​Vth_default and temperature threshold T_limit for the DC bus voltage protection threshold.

[0097] Initialization can be performed to load the default values ​​of the DC bus voltage protection threshold Vth (Vth_default) and temperature threshold T_limit.

[0098] Step 220: Sample the temperature of the switching device in real time.

[0099] The temperature Tc of each switching device can be obtained by sampling the heat sink temperature of each switching device in real time using a temperature sensor.

[0100] Step 230: Determine whether the temperature of the switching device is greater than the temperature threshold T_limit.

[0101] Determine whether the temperature Tc of any switching device is greater than the temperature threshold T_limit. If yes, proceed to step 240; otherwise, proceed to step 260.

[0102] Step 240: Calculate the new voltage protection threshold Vth based on the temperature of the switching device.

[0103] This can be achieved through a pre-stored linear function Vth = Vth_default - k (Tc-25) Calculates a new voltage protection threshold Vth that differs from the default value Vth_default. Vth_default can be the base threshold Vth_base corresponding to a base temperature Tb of 25℃; k is the derating factor; and Tc can be the maximum value among the temperatures Tc of all switching devices in the power conversion device whose temperatures exceed the temperature threshold T_limit.

[0104] Step 250: Set the new voltage protection threshold Vth to the currently valid voltage protection threshold.

[0105] Step 260: Set the default value Vth_default to the currently valid voltage protection threshold.

[0106] Step 270: Sample the current voltage Vdc of the DC bus.

[0107] Sample the current voltage Vdc of the DC bus to obtain the current voltage Vdc of the DC bus.

[0108] Step 280: Determine whether Vdc is greater than or equal to the current effective voltage protection threshold.

[0109] If yes, then proceed to step 290; otherwise, return to step 220.

[0110] Step 290: Trigger overvoltage protection action.

[0111] It can trigger overvoltage protection actions such as shutdown or derating operation.

[0112] The voltage protection threshold determination method provided in this application can be executed by a voltage protection threshold determination device. This application uses an example of a voltage protection threshold determination device executing the voltage protection threshold determination method to illustrate the voltage protection threshold determination device provided in this application.

[0113] This application also provides a device for determining a voltage protection threshold. For example... Figure 3 As shown, the device for determining the voltage protection threshold includes a temperature acquisition module 310 and a threshold determination module 320.

[0114] Temperature acquisition module 310 is used to acquire the temperature of each switching device in the power conversion device; The threshold determination module 320 is used to determine the voltage protection threshold of the DC bus in the power conversion device based on the temperature of each switching device when the temperature of at least one switching device is greater than a temperature threshold.

[0115] According to the voltage protection threshold determination device provided in the embodiments of this application, when the temperature of at least one switching device in the power conversion device is greater than the temperature threshold, the voltage protection threshold of the DC bus in the power conversion device is dynamically determined based on the temperature of each switching device, which can take into account both the utilization rate and safety of the inverter.

[0116] In some embodiments of this application, the threshold determination module 320 can be specifically used to determine the voltage protection threshold based on the temperature of each switching device, the reference temperature, and the reference threshold corresponding to the reference temperature.

[0117] In some embodiments of this application, the threshold determination module 320 may include: The acquisition unit is used to acquire the target temperature difference based on the temperature of each switching device and the reference temperature; The determination unit is used to determine the voltage protection threshold based on the reference threshold and the target temperature difference.

[0118] In some embodiments of this application, the determining unit may be specifically used for: Obtain the product of the target temperature difference and the derating factor; the derating factor is used to indicate the rate of change of the withstand voltage of the switching device with temperature. The difference between the reference threshold and the product is used as the voltage protection threshold.

[0119] In some embodiments of this application, the acquisition unit may include: The first acquisition subunit is used to acquire the temperature difference between the temperature of each switching device and the reference temperature. The second acquisition subunit is used to acquire the target temperature difference based on each temperature difference.

[0120] In some embodiments of this application, the second acquisition subunit may be specifically used to determine the maximum value, average value, median or weighted average value of each temperature difference as the target temperature difference.

[0121] The device for determining the voltage protection threshold in this application embodiment can be an electronic device or a component within an electronic device, such as an integrated circuit or a chip. The electronic device can be a terminal or other devices besides a terminal. For example, the electronic device can be a mobile phone, tablet computer, laptop computer, PDA, in-vehicle electronic device, mobile internet device (MID), augmented reality (AR) / virtual reality (VR) device, robot, wearable device, ultra-mobile personal computer (UMPC), netbook, or personal digital assistant (PDA), etc. It can also be a server, network attached storage (NAS), personal computer (PC), television (TV), ATM, or self-service machine, etc. This application embodiment does not specifically limit the specific device.

[0122] The device for determining the voltage protection threshold in this application embodiment can be a device with an operating system. This operating system can be a Microsoft (Windows) operating system, an Android operating system, an iOS operating system, or other possible operating systems; this application embodiment does not specifically limit it.

[0123] The voltage protection threshold determination device provided in this application embodiment can achieve... Figures 1 to 2 The various processes implemented in the method implementation examples will not be described again here to avoid repetition.

[0124] This application also provides a power conversion system. In some embodiments, such as Figure 4 As shown, the power conversion system 400 includes a power conversion device 410 and a voltage protection threshold determination device 420.

[0125] In actual implementation, the voltage protection threshold determination device 420 can be any of the voltage protection threshold determination devices provided in the foregoing embodiments of this application.

[0126] According to the power conversion system provided in the embodiments of this application, when the temperature of at least one switching device in the power conversion device is greater than the temperature threshold, the voltage protection threshold of the DC bus in the power conversion device is dynamically determined based on the temperature of each switching device, which can take into account both the utilization rate and safety of the inverter.

[0127] In some embodiments, such as Figure 5 As shown, this application embodiment also provides a power conversion device 500, including a processor 501, a memory 502, and a computer program stored in the memory 502 and executable on the processor 501. When the computer program is executed by the processor 501, it implements the various processes of the above-mentioned voltage protection threshold determination method embodiment and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0128] It should be noted that the power conversion device in the embodiments of this application includes the mobile electronic device and the non-mobile electronic device described above.

[0129] This application also provides a non-volatile computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the various processes of the above-described method embodiment for determining the voltage protection threshold and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0130] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0131] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the method for determining the voltage protection threshold.

[0132] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0133] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described method embodiment for determining the voltage protection threshold, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0134] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0135] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0136] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the related technology, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0137] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0138] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0139] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for determining a voltage protection threshold, characterized in that, include: Obtain the temperature of each switching device in the power conversion device; If the temperature of at least one of the switching devices is greater than a temperature threshold, a voltage protection threshold for the DC bus in the power conversion device is determined based on the temperature of each of the switching devices.

2. The method for determining the voltage protection threshold according to claim 1, characterized in that, Determining the voltage protection threshold of the DC bus in the power conversion device based on the temperature of each of the switching devices includes: The voltage protection threshold is determined based on the temperature of each of the switching devices, the reference temperature, and the reference threshold corresponding to the reference temperature.

3. The method for determining the voltage protection threshold according to claim 2, characterized in that, The determination of the voltage protection threshold based on the temperature of each of the switching devices, a reference temperature, and a reference threshold corresponding to the reference temperature includes: The target temperature difference is obtained based on the temperature of each of the switching devices and the reference temperature; The voltage protection threshold is determined based on the reference threshold and the target temperature difference.

4. The method for determining the voltage protection threshold according to claim 3, characterized in that, Determining the voltage protection threshold based on the reference threshold and the target temperature difference includes: Obtain the product of the target temperature difference and the derating factor; the derating factor is used to indicate the rate of change of the withstand voltage of the switching device with temperature. The difference between the reference threshold and the product is obtained as the voltage protection threshold.

5. The method for determining the voltage protection threshold according to claim 3 or 4, characterized in that, The step of obtaining the target temperature difference based on the temperature of each of the switching devices and the reference temperature includes: The temperature difference between the temperature of each of the switching devices and the reference temperature is obtained respectively; The target temperature difference is obtained based on each of the aforementioned temperature differences.

6. The method for determining the voltage protection threshold according to claim 5, characterized in that, The step of obtaining the target temperature difference based on each of the temperature differences includes: The maximum, average, median, or weighted average of each of the aforementioned temperature differences is determined as the target temperature difference.

7. A device for determining a voltage protection threshold, characterized in that, include: Temperature acquisition module is used to acquire the temperature of each switching device in the power conversion device; A threshold determination module is used to determine a voltage protection threshold for the DC bus in the power conversion device based on the temperature of each of the switching devices when the temperature of at least one of the switching devices is greater than a temperature threshold.

8. A power conversion system, characterized in that, It includes a power conversion device and a voltage protection threshold determination device as described in claim 7.

9. A power conversion device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for determining the voltage protection threshold as described in any one of claims 1 to 6.

10. A non-volatile computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for determining the voltage protection threshold as described in any one of claims 1 to 6.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for determining the voltage protection threshold as described in any one of claims 1 to 6.

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