Method and system for abnormal protection of converter valve junction temperature according to water cooling flow rate adjustment

Abstract

A method and system for abnormal protection of the commutation valve junction temperature according to the regulation of the water-cooling flow rate, including: using a temperature sensor to measure the junction temperature of each current-carrying component of the commutation valve in real time, and calculating the comprehensive junction temperature abnormality index of each current-carrying component according to the junction temperature and the junction temperature change rate; if there is a comprehensive junction temperature abnormality index of a current-carrying component greater than or equal to the set index threshold of the corresponding current-carrying component, then combining the frictional resistance and local resistance along the water-cooling system, calculating the maximum flow rate of the water-cooling system according to the rated power of the water-cooling system; establishing a loss function that combines the heat generation-related losses of the corresponding current-carrying component, the thermal resistance from the radiator of the water-cooling system to the cooling medium, and the loss of the inlet and outlet water temperatures; using the maximum flow rate as a constraint condition, adjusting the flow rate until the loss function reaches the minimum. The present invention can dynamically adjust the water-cooling flow rate to control the temperature reduction when the commutation valve junction temperature is abnormal, improving the operating safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of converter valve safety protection, and more specifically, relates to a method and system for abnormal protection of the converter valve junction temperature according to the adjustment of the water cooling flow rate. Background Art

[0002] The current-carrying components in the converter valve, such as thyristors and IGBT components in a controllable commutation converter valve, generate losses during operation, which will cause the junction temperature of the components to rise. Moreover, in some applications, changes in the working load, ambient temperature, current load, and switching frequency of the converter valve will also cause fluctuations in the junction temperature of the converter valve components. Especially when there are situations such as component aging and damage, unstable gate control, and external electromagnetic interference, the junction temperature of the components may experience sudden changes or significant increases, putting the components and equipment in a high-temperature state. For safety protection design, to ensure that the junction temperature of thyristors and IGBT components during steady-state operation is within the allowable range, a water cooling system needs to be equipped for heat dissipation.

[0003] CN116973720A proposes a method and system for estimating the junction temperature of an IGBT module in an electric vehicle, belonging to the field of estimating the junction temperature of an IGBT in an electric vehicle. The method includes performing current biasing, voltage biasing, and temperature biasing on the IGBT module in an electric vehicle under actual working conditions according to the double-pulse test principle to obtain the turn-on loss of the IGBT device, the turn-off loss of the IGBT device, and the reverse recovery loss of the diode; obtaining the working condition parameters of the IGBT module in the electric vehicle, and using the IGBT module loss calculation method based on the working condition parameters, the turn-on loss of the IGBT device, the turn-off loss of the IGBT device, and the reverse recovery loss of the diode to obtain the loss result; obtaining the IGBT thermal impedance considering the coolant water temperature and flow rate according to the step response method; and obtaining the junction temperature of the IGBT module in the electric vehicle based on the loss result and the IGBT thermal impedance considering the coolant water temperature and coolant flow rate. However, this patent only detects abnormal junction temperature and does not reduce the temperature to prevent overheating;

[0004] CN119051642A proposes a MOS field - effect transistor gate driving method, device, equipment and storage medium. The method includes: sampling the original driving signal of the MOS field - effect transistor to obtain a first driving signal; establishing a dynamic characteristic data table; calculating a non - linear ideal gate voltage change curve and obtaining a second driving signal; amplifying it and connecting it to the MOS field - effect transistor gate through a dynamic impedance matching network to obtain a power - matching signal; inputting the current detection result into a digital signal processor to obtain an adaptive driving signal; analyzing the change rate of the drain - source voltage and estimating the junction temperature, and adjusting the slope and amplitude of the adaptive driving signal when an abnormality is detected. This patent reduces the junction temperature by adjusting the slope and amplitude of the adaptive driving signal when the junction temperature is abnormal, but it will change the driving situation of the converter, and adjusting the driving signal without considering component damage and other situations cannot reduce the junction temperature, resulting in potential safety hazards.

[0005] CN118517777A proposes a water - cooled machine environment - adaptability intelligent regulation system, including an environment perception module, a data processing module, a cooling demand prediction module, an intelligent regulation module, an actuator module, and a fault prediction and self - healing module. The environment perception module monitors the environment temperature in real - time. The data processing module analyzes and processes the environment data. The cooling demand prediction module predicts the optimal cooling strategy. The intelligent regulation module calculates the best operation instruction. The actuator module adjusts the operating parameters of the water - cooled machine. The fault prediction and self - healing module gives early warnings and processes before a fault occurs, and starts the self - healing mechanism when a fault occurs. However, this patent only adjusts the water - cooling system according to the temperature data of the water - cooled machine itself and the temperature to be adjusted, and does not combine with the equipment that actually needs to be cooled, and does not consider the power loss problem of the water - cooling system. Summary of the Invention

[0006] To solve the deficiencies in the prior art, the present invention provides a method and system for protecting the abnormal junction temperature of a converter valve according to the adjustment of water - cooling flow rate.

[0007] The present invention adopts the following technical solutions.

[0008] In the first aspect of the present invention, a method for protecting the abnormal junction temperature of a converter valve according to the adjustment of water - cooling flow rate is proposed, including the following:

[0009] Using temperature sensors to measure the junction temperature of each current - conducting element of the converter valve in real - time. The current - conducting elements include thyristors and IGBTs, and measure the inlet and outlet water temperatures of the water - cooling system. Calculate the comprehensive junction temperature abnormality index of each current - conducting element according to the junction temperature and the junction temperature change rate;

[0010] If the comprehensive junction temperature anomaly index of the current-carrying component is greater than or equal to the set index threshold of the corresponding current-carrying component, obtain the thermal resistance curve between the flow velocity and the thermal resistance from the radiator of the water-cooling system to the cooling medium through simulation; combine the frictional resistance and local resistance along the water-cooling system, and calculate the maximum flow velocity of the water-cooling system according to the rated power of the water-cooling system.

[0011] Establish a loss function that combines the heat-related losses of the corresponding current-carrying component, the thermal resistance from the radiator of the water-cooling system to the cooling medium, and the temperature loss of the inlet and outlet water.

[0012] With the maximum flow velocity as the constraint condition, continuously adjust the flow velocity. After each adjustment, obtain the thermal resistance from the radiator of the water-cooling system to the cooling medium corresponding to the adjusted flow velocity by querying the thermal resistance curve, and calculate the heat-related losses of the corresponding current-carrying component after each adjustment, so as to calculate the loss function after each adjustment, and adjust the flow velocity until the loss function reaches the minimum.

[0013] Preferably, the temperature sensor is a resistance temperature detector (RTD) or a thermocouple; when the current-carrying component is a thyristor, both the anode and cathode of the thyristor are connected to the radiator of the water-cooling system; the thyristor junction temperature is the average value of the temperatures measured at both ends of the anode and cathode of the thyristor; when the current-carrying component is an IGBT, both the collector and emitter of the IGBT are connected to the radiator of the water-cooling system; the IGBT junction temperature is the average value of the temperatures measured at both ends of the collector and emitter of the IGBT.

[0014] Preferably, the comprehensive junction temperature anomaly index The calculation formula is:

[0015]

[0016] In the formula, is a coefficient with a set value ranging from 0 to 1, is the junction temperature change rate, , are the junction temperatures of the current-carrying component measured at the previous moment and the current moment respectively, , are the times at the previous moment and the current moment respectively.

[0017] Preferably, the value range of the index threshold of the corresponding current-carrying component is:

[0018]

[0019] In the formula, is the maximum junction temperature of the corresponding current-carrying component.

[0020] Preferably, combining the frictional resistance and local resistance along the water-cooling system, calculating the maximum flow velocity of the water-cooling system according to the rated power of the water-cooling system is specifically:

[0021] The formula for calculating the sum of the maximum frictional resistance and the maximum local resistance based on the maximum flow rate and the rated power of the water cooling system is as follows:

[0022]

[0023] In the formula, is the maximum frictional resistance, is the maximum local resistance, d is the inner diameter of the pipe, is the set maximum power coefficient, is the flow coefficient, is the density of the coolant in the water cooling system, is the acceleration due to gravity, is the rated power of the water cooling system, is the maximum flow rate;

[0024] The formula for calculating the maximum frictional resistance and the maximum local resistance based on the maximum flow rate is as follows:

[0025]

[0026]

[0027] In the formula, C h is the Hazen-Williams coefficient; is the local resistance coefficient;

[0028] Substitute the two formulas for calculating the maximum frictional resistance and the maximum local resistance based on the maximum flow rate into the formula for calculating the sum of the maximum frictional resistance and the maximum local resistance based on the maximum flow rate and the rated power of the water cooling system, and solve by iteration to obtain the maximum flow rate of the water cooling system.

[0029] Preferably, the flow coefficient is obtained by simulating the water cooling system to obtain the flow rate corresponding to the flow velocity. According to the flow rate corresponding to the flow velocity, it is calculated using the relationship formula between the flow coefficient, the flow velocity and the flow rate, or is set according to the pipe design of the water cooling system and the additional components of the water cooling system. The pipe design includes pipe diameter selection and series-parallel connection methods of the water circuit; the additional components include pipe elbows, valves, and joints;

[0030] Relationship formula between the flow coefficient, the flow velocity and the flow rate:

[0031]

[0032] In the formula, is the flow rate, is the flow velocity.

[0033] Preferably, a loss function related to the heat generation of the flow-through element corresponding at this moment, the thermal resistance from the radiator of the water cooling system to the cooling medium, and the loss of the inlet and outlet water temperatures is established, and the flow rate is dynamically adjusted with the maximum flow rate as the constraint condition and the minimum loss function as the target. Specifically:

[0034] Loss function is:

[0035]

[0036] In the formula, is the loss related to the heat generation of the flow-through element corresponding at this moment, is the junction-case thermal resistance from the die to the case, is the contact thermal resistance from the case to the radiator of the water cooling system, is the thermal resistance from the radiator of the water cooling system to the cooling medium corresponding to the flow rate at this moment, is the proportionality coefficient of the direct heat dissipation of the case to the external environment, , are the inlet water temperature and the outlet water temperature respectively, is the rated junction temperature of the corresponding flow-through element.

[0037] The loss related to the heat generation of the flow-through element is specifically:

[0038] If the flow-through element is a thyristor, the loss of the flow-through element is the sum of the conduction loss, turn-on loss, and turn-off loss of the thyristor. If the flow-through element is an IGBT, the loss of the flow-through element is the IGBT conduction loss.

[0039] Preferably, the conduction loss of the IGBT The calculation formula is:

[0040]

[0041] In the formula, is the conduction voltage of the IGBT, is the current passing through the IGBT, is the IGBT switching frequency;

[0042] The conduction loss of the thyristor , turn-on loss and turn-off loss The calculation formulas are respectively:

[0043]

[0044]

[0045]

[0046] In the formula, is the conduction voltage drop of the thyristor, is the conduction current of the thyristor, is the duty cycle of thyristor conduction; is the voltage of the thyristor during the turn-on process, is the current of the thyristor during the turn-on process, is the operating frequency of the thyristor, is the turn-on time of the thyristor, is the turn-off time of the thyristor.

[0047] The second aspect of the present invention proposes a commutation valve junction temperature abnormal protection system for regulating according to the water cooling flow rate using the method described in the first aspect of the present invention, including a measurement module, a comprehensive junction temperature abnormal index calculation module, a maximum flow rate calculation module, a loss function establishment module, and a flow rate adjustment module, characterized in that:

[0048] Measurement module: used to measure the junction temperature of each current-carrying component of the controllable commutation valve in real time using a temperature sensor. The current-carrying components include thyristors and IGBTs, and measure the inlet and outlet water temperatures of the water cooling system;

[0049] Comprehensive junction temperature abnormal index calculation module: used to calculate the comprehensive junction temperature abnormal index of each current-carrying component according to the junction temperature and the junction temperature change rate; if the comprehensive junction temperature abnormal index of a current-carrying component is greater than or equal to the set index threshold of the corresponding current-carrying component, obtain the thermal resistance curve between the flow rate and the thermal resistance from the radiator of the water cooling system to the cooling medium through simulation;

[0050] Maximum flow rate calculation module: combine the frictional resistance and local resistance along the water cooling system, and calculate the maximum flow rate of the water cooling system according to the rated power of the water cooling system;

[0051] Loss function establishment module: establish a loss function combining the heat generation-related losses of the corresponding current-carrying components, the thermal resistance from the radiator of the water cooling system to the cooling medium, and the inlet and outlet water temperatures;

[0052] Flow rate adjustment module: with the maximum flow rate as the constraint condition, continuously adjust the flow rate. After each adjustment, obtain the thermal resistance from the radiator of the water cooling system to the cooling medium corresponding to the adjusted flow rate by querying the thermal resistance curve, and calculate the heat generation-related losses of the corresponding current-carrying components after each adjustment, so as to calculate the loss function after each adjustment, and adjust the flow rate until the loss function reaches the minimum.

[0053] The beneficial effects of the present invention are as follows. Compared with the prior art, the present invention measures the junction temperature of the current-carrying components of the converter valve, calculates the comprehensive junction temperature abnormality index of each current-carrying component according to the junction temperature and the junction temperature change rate, and determines whether it is abnormal through the comprehensive junction temperature abnormality index so as to adjust the water cooling, taking into account sudden changes; the present invention combines the frictional resistance and local resistance along the water cooling system, calculates the maximum flow rate of the water cooling system according to the rated power of the water cooling system, and controls the power of the water cooling system within a certain range while adjusting the flow rate, making the water cooling adjustment more reasonable; the present invention establishes a loss function combining the heat-related losses of the corresponding current-carrying components, the thermal resistance from the radiator of the water cooling system to the cooling medium, and the loss of the inlet and outlet water temperatures; through this loss function, the dynamic adjustment of the water cooling flow rate can effectively prevent component damage caused by too high junction temperature and will not overly increase the loss of the water cooling system, keeping the temperature of the current-carrying components within a safe range. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a flowchart of the present invention;

[0055] Figure 2 is an equivalent thermal circuit diagram of the current-carrying component. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The embodiments described in this application are only a part of the embodiments of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0057] As Figure 1 shown, Embodiment 1 of the present invention proposes a method for protecting the converter valve against abnormal junction temperature according to the adjustment of the water cooling flow rate, including the following:

[0058] Use a temperature sensor to measure the junction temperature of each current-carrying component of the converter valve in real time. The current-carrying components include thyristors and IGBTs, and measure the inlet and outlet water temperatures of the water cooling system. Calculate the comprehensive junction temperature abnormality index of each current-carrying component according to the junction temperature and the junction temperature change rate;

[0059] It should be noted that the converter valve adopted in this embodiment is a controllable commutation converter valve.

[0060] If the comprehensive junction temperature abnormality index of a current-carrying component is greater than or equal to the set index threshold of the corresponding current-carrying component, obtain the thermal resistance curve between the flow rate and the thermal resistance from the radiator of the water cooling system to the cooling medium through simulation; combine the frictional resistance and local resistance along the water cooling system, and calculate the maximum flow rate of the water cooling system according to the rated power of the water cooling system;

[0061] It should be noted that if the adjusted flow rate calculated subsequently is too large, it may be difficult for the operating power of the water cooling system to match it. Therefore, by combining the frictional resistance and local resistance along the water cooling system, the maximum flow rate is calculated, and the flow rate is adjusted within this range; if the flow rate is too low and the ambient temperature is also too low, resulting in a low inlet and outlet water temperature, an electric heater is added near the water cooling system to forcibly compensate the temperature of the cooling water to prevent the condensation phenomenon caused by too low temperature.

[0062] A loss function is established by combining the heat-related losses of the corresponding flow-through components, the thermal resistance from the radiator of the water cooling system to the cooling medium, and the loss of the inlet and outlet water temperature.

[0063] Taking the maximum flow rate as a constraint condition, the flow rate is continuously adjusted. After each adjustment, the thermal resistance from the radiator of the water cooling system to the cooling medium corresponding to the adjusted flow rate is obtained by querying the thermal resistance curve, and the heat-related losses of the corresponding flow-through components are calculated after each adjustment, so as to calculate the loss function after each adjustment, and the flow rate is adjusted until the loss function reaches the minimum.

[0064] It should be noted that if the finally adjusted flow rate is the maximum flow rate, an alarm is given to the staff to remind the staff to check, so as to prevent a large increase in the junction temperature caused by faults such as aging or damage of the flow-through components or external electromagnetic interference at this time.

[0065] Preferably, the temperature sensor is a resistance temperature detector RTD or a thermocouple; when the flow-through component is a thyristor, both the anode and cathode of the thyristor are connected to the radiator of the water cooling system; the thyristor junction temperature is the average value of the temperatures measured at both ends of the anode and cathode of the thyristor; when the flow-through component is an IGBT, both the collector and emitter of the IGBT are connected to the radiator of the water cooling system; the IGBT junction temperature is the average value of the temperatures measured at both ends of the collector and emitter of the IGBT.

[0066] Preferably, the comprehensive junction temperature anomaly index The calculation formula is:

[0067]

[0068] In the formula, is a coefficient with a set value ranging from 0 to 1, is the junction temperature change rate, , are the junction temperatures of the flow-through components measured at the previous moment and this moment respectively, , are the times at the previous moment and this moment respectively.

[0069] Preferably, the value range of the index threshold of the corresponding flow-through component is:

[0070]

[0071] In the formula, is the maximum junction temperature of the corresponding flow-through component.

[0072] Preferably, considering the frictional resistance and local resistance along the water-cooling system, the maximum flow rate of the water-cooling system is calculated according to the rated power of the water-cooling system, specifically:

[0073] The formula for calculating the sum of the maximum frictional resistance and the maximum local resistance according to the maximum flow rate and the rated power of the water-cooling system is:

[0074]

[0075] In the formula, is the maximum frictional resistance, is the maximum local resistance, d is the inner diameter of the pipeline, is the set maximum power coefficient, is the flow coefficient, is the density of the coolant in the water-cooling system, is the acceleration of gravity, is the rated power of the water-cooling system, is the maximum flow rate;

[0076] Specifically, the maximum power coefficient of this embodiment is 30%.

[0077] The formula for calculating the maximum frictional resistance and the maximum local resistance according to the maximum flow rate is:

[0078]

[0079]

[0080] In the formula, C h is the Hazen-Williams coefficient; is the local resistance coefficient;

[0081] Substitute these two formulas for calculating the maximum frictional resistance and the maximum local resistance according to the maximum flow rate into the formula for calculating the sum of the maximum frictional resistance and the maximum local resistance according to the maximum flow rate and the rated power of the water-cooling system, and solve by iteration to obtain the maximum flow rate of the water-cooling system.

[0082] Preferably, the flow coefficient is obtained by simulating the water-cooling system to obtain the flow rate corresponding to the flow velocity, and calculating according to the relationship formula between the flow coefficient, the flow velocity and the flow rate based on the flow rate corresponding to the flow velocity, or is set according to the pipeline design of the water-cooling system and the additional components of the water-cooling system. The pipeline design includes pipe diameter selection and series-parallel connection methods of the water circuit; the additional components include pipe elbows, valves, and joints.

[0083] Formula for the relationship between flow coefficient, flow velocity and flow rate:

[0084]

[0085] Wherein, is the flow rate, is the flow velocity.

[0086] Specifically, the flow coefficient obtained by simulating the water cooling system through 3D software in this embodiment is 1.881.

[0087] Preferably, a loss function combining the heat-related losses of the current corresponding flow-through component, the thermal resistance from the radiator of the water cooling system to the cooling medium, and the losses of the inlet and outlet water temperatures is established, and the flow velocity is dynamically adjusted with the maximum flow velocity as the constraint condition and the minimum loss function as the target. Specifically:

[0088] The loss function is:

[0089]

[0090] Wherein, is the heat-related loss of the current corresponding flow-through component, is the thermal resistance of the corresponding flow-through component, , are the inlet water temperature and the outlet water temperature respectively, is the rated junction temperature of the corresponding flow-through component.

[0091] It should be noted that during the heat exchange process, the heat of the thyristor and IGBT components is transferred from the chip to the shell, then from the shell to the radiator, and finally from the surface of the radiator to the cooling medium. At the same time, a part of the heat is directly dissipated to the external environment through the shell. When the flow-through component is a thyristor, both the anode and cathode of the thyristor are connected to the radiator of the water cooling system; when the flow-through component is an IGBT, both the collector and emitter of the IGBT are connected to the radiator of the water cooling system; the equivalent thermal circuit diagrams of the thyristor and IGBT are both as Figure 2 shown. Therefore, the calculation formula of the thermal resistance of the flow-through component is:

[0092]

[0093]

[0094] Wherein, is the equivalent thermal resistance from the anode of the thyristor or the collector of the IGBT to the radiator connected thereto, is the equivalent thermal resistance from the cathode of the thyristor or the emitter of the IGBT to the radiator connected thereto; the subscript When it is A, it represents the thermal resistance corresponding to the thermal path from the anode of the thyristor or the collector of the IGBT to the radiator connected thereto. When it is B, it represents the thermal resistance corresponding to the thermal path from the cathode of the thyristor or the emitter of the IGBT to the radiator connected thereto. is the proportionality coefficient of the direct heat dissipation of the housing on the corresponding thermal path to the external environment, is the junction-case thermal resistance from the die to the housing on the corresponding thermal path, is the contact thermal resistance from the housing on the corresponding thermal path to the radiator of the water cooling system, is the thermal resistance from the radiator of the water cooling system corresponding to the current flow rate on the corresponding thermal path to the cooling medium;

[0095] Since the structural materials such as the radiator and pipeline of the water cooling system adopted in this embodiment are always the same, therefore, the calculation formula for the thermal resistance

[0096]

[0097] In the formula, is the proportionality coefficient of the direct heat dissipation of the housing to the external environment, is the junction-case thermal resistance from the die to the housing, is the contact thermal resistance from the housing to the radiator of the water cooling system, is the thermal resistance from the radiator of the water cooling system corresponding to the current flow rate to the cooling medium;

[0098] Specifically, is related to the material of the pipeline of the water cooling system. In this embodiment, is 0.01.

[0099] The final loss function is:

[0100]

[0101] Preferably, the heat generation related losses of the current-carrying component are specifically:

[0102] If the current-carrying component is a thyristor, the loss of the current-carrying component is the sum of the conduction loss, turn-on loss and turn-off loss of the thyristor. If the current-carrying component is an IGBT, the loss of the current-carrying component is the IGBT conduction loss.

[0103] Preferably, the conduction loss of the IGBT

[0104]

[0105] In the formula, is the conduction voltage of the IGBT, is the current passing through the IGBT, is the switching frequency of the IGBT;

[0106] The conduction loss of the thyristor , turn-on loss and turn-off loss The calculation formulas are respectively:

[0107]

[0108]

[0109]

[0110] In the formula, is the conduction voltage drop of the thyristor, is the conduction current of the thyristor, is the duty cycle of the thyristor conduction; is the voltage of the thyristor during the turn-on process, is the current of the thyristor during the turn-on process, is the operating frequency of the thyristor, is the turn-on time of the thyristor, is the turn-off time of the thyristor.

[0111] Embodiment 2 of the present invention proposes a commutation valve junction temperature abnormal protection system according to the water cooling flow rate adjustment using the method described in Embodiment 1 of the present invention, including a measurement module, a comprehensive junction temperature abnormal index calculation module, a maximum flow rate calculation module, a loss function establishment module, and a flow rate adjustment module, characterized in that:

[0112] Measurement module: used to measure the junction temperature of each current-carrying component of the controllable phase-shifting commutation valve in real time using a temperature sensor. The current-carrying components include thyristors and IGBTs, and measure the inlet and outlet water temperatures of the water cooling system;

[0113] Comprehensive junction temperature abnormal index calculation module: used to calculate the comprehensive junction temperature abnormal index of each current-carrying component according to the junction temperature and the junction temperature change rate; if the comprehensive junction temperature abnormal index of a current-carrying component is greater than or equal to the set index threshold of the corresponding current-carrying component, obtain the thermal resistance curve between the flow rate and the thermal resistance from the radiator of the water cooling system to the cooling medium through simulation;

[0114] Maximum flow rate calculation module: combined with the frictional resistance and local resistance along the water cooling system, calculate the maximum flow rate of the water cooling system according to the rated power of the water cooling system;

[0115] Loss function establishment module: Establish a loss function that combines the heat-related losses of the corresponding flow components, the thermal resistance from the radiator of the water cooling system to the cooling medium, and the inlet and outlet water temperatures.

[0116] Flow rate adjustment module: With the maximum flow rate as the constraint condition, continuously adjust the flow rate. After each adjustment, obtain the thermal resistance from the radiator of the water cooling system to the cooling medium corresponding to the adjusted flow rate by querying the thermal resistance curve, and calculate the heat-related losses of the corresponding flow components after each adjustment, so as to calculate the loss function after each adjustment. Adjust the flow rate until the loss function reaches the minimum.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the specific implementation manners of the present invention or make equivalent replacements, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for protecting a converter valve from abnormal junction temperature by adjusting the water cooling flow rate, characterized in that: Includes the following: Using a temperature sensor to measure the junction temperature of each flow element of the converter valve in real time, the flow element includes a thyristor and an IGBT, and measuring the inlet and outlet water temperatures of the water cooling system, and calculating the comprehensive junction temperature abnormality index of each flow element according to the junction temperature and the junction temperature change rate; If the comprehensive junction temperature abnormality index of the flow element is greater than or equal to the set index threshold of the corresponding flow element, the thermal resistance curve between the flow rate and the thermal resistance from the radiator to the cooling medium of the water cooling system is obtained through simulation; the maximum flow rate of the water cooling system is calculated according to the rated power of the water cooling system in combination with the along-the-line resistance and local resistance of the water cooling system; Establish a loss function combining the heat-related losses of the flow-through element corresponding to the moment, the thermal resistance from the radiator to the cooling medium of the water cooling system, and the inlet and outlet water temperatures; Taking the maximum flow rate as the constraint, the flow rate is continuously adjusted. After each adjustment, the thermal resistance from the radiator to the cooling medium of the water cooling system corresponding to the adjusted flow rate is obtained by querying the thermal resistance curve. The heat-related losses of the corresponding flow-through elements are calculated after each adjustment, thereby calculating the loss function after each adjustment, and adjusting the flow rate until the loss function reaches the minimum.

2. The method for protecting a converter valve from abnormal junction temperature by adjusting the water cooling flow rate according to claim 1, characterized in that: The temperature sensor is a resistance temperature detector (RTD) or a thermocouple; when the flow element is a thyristor, the anode and cathode of the thyristor are both connected to the radiator of the water cooling system; the thyristor junction temperature is the average temperature measured at the anode and cathode of the thyristor; when the flow element is an IGBT, the collector and emitter of the IGBT are both connected to the radiator of the water cooling system; the IGBT junction temperature is the average temperature measured at the collector and emitter of the IGBT.

3. The method for protecting a converter valve against abnormal junction temperature by adjusting the water cooling flow rate according to claim 1, characterized in that: The comprehensive junction temperature abnormality index The calculation formula is: In the formula, is a coefficient with a value between 0 and 1. is the junction temperature change rate, , are the junction temperatures of the flow element measured at the last moment and this moment respectively, , They are the time of the previous moment and the time of this moment respectively.

4. The method for protecting a converter valve against abnormal junction temperature according to water cooling flow rate regulation according to claim 3, characterized in that: The value range of the index threshold of the corresponding flow element is: In the formula, is the maximum junction temperature of the corresponding flow element.

5. The method for protecting a converter valve against abnormal junction temperature according to water cooling flow rate regulation according to claim 1, characterized in that: The maximum flow rate of the water cooling system is calculated according to the rated power of the water cooling system in combination with the resistance along the water cooling system and the local resistance, specifically: The formula for calculating the sum of the maximum along-the-line resistance and the maximum local resistance based on the maximum flow rate and rated power of the water cooling system is: In the formula, is the maximum resistance along the path, is the maximum local resistance, d is the inner diameter of the pipe, is the set maximum power factor, is the flow coefficient, is the density of the coolant in the water cooling system, is the acceleration due to gravity, is the rated power of the water cooling system, is the maximum flow rate; The formula for calculating the maximum along-the-way resistance and the maximum local resistance based on the maximum flow velocity is: In the formula, C h is the Haicheng William coefficient; is the local resistance coefficient; The two formulas for calculating the maximum along-the-path resistance and the maximum local resistance according to the maximum flow velocity are substituted into the sum of the maximum along-the-path resistance and the maximum local resistance calculated according to the maximum flow velocity and rated power of the water cooling system, and the maximum flow velocity of the water cooling system is obtained by iterative solution.

6. The method for protecting a converter valve from abnormal junction temperature by adjusting the water cooling flow rate according to claim 5, characterized in that: Flow coefficient By simulating the water cooling system, the flow rate corresponding to the flow velocity is obtained, and the flow rate corresponding to the flow velocity is calculated using the flow coefficient, the relationship between the flow velocity and the flow rate, or it is set according to the pipeline design of the water cooling system and the additional components of the water cooling system, the pipeline design includes the selection of pipe diameters and the series and parallel connection of water channels; the additional components include pipeline elbows, valves, and joints; The relationship formula between flow coefficient, flow velocity and flow rate: In the formula, For flow, is the flow rate.

7. The method for protecting a converter valve against abnormal junction temperature by adjusting the water cooling flow rate according to claim 6, characterized in that: The establishment combines the heat-related losses of the flow element corresponding to the moment, the thermal resistance from the radiator to the cooling medium of the water cooling system, and the inlet and outlet water temperatures, takes the maximum flow rate as a constraint, and dynamically adjusts the flow rate with the minimum loss function as the goal, specifically: Loss Function for: In the formula, The corresponding heat loss of the flow element at this moment is: is the junction-to-case thermal resistance from die to case, is the thermal contact resistance from the tube shell to the radiator of the water cooling system, The thermal resistance from the radiator to the cooling medium of the water cooling system corresponding to the flow rate at this moment is: is the proportional coefficient of heat dissipation from the tube shell directly to the external environment, , are the inlet water temperature and outlet water temperature, is the rated junction temperature of the corresponding flow element.

8. The method for protecting a converter valve against abnormal junction temperature according to water cooling flow rate regulation according to claim 7, characterized in that: The heat-related losses of the flow-through element are specifically: If the flow element is a thyristor, the loss of the flow element is the sum of the conduction loss, turn-on loss and turn-off loss of the thyristor. If the flow element is an IGBT, the loss of the flow element is the conduction loss of the IGBT.

9. The method for protecting a converter valve against abnormal junction temperature by adjusting the water cooling flow rate according to claim 8, characterized in that: IGBT conduction loss The calculation formula is: In the formula, is the on-state voltage of the IGBT, is the current through the IGBT, is the IGBT switching frequency; Conduction loss of thyristor , Turn-on loss and turn-off losses The calculation formulas are: In the formula, is the conduction voltage drop of the thyristor, is the conduction current of the thyristor, is the duty cycle of the thyristor conduction; is the voltage of the thyristor during the turn-on process, is the current of the thyristor during the turn-on process, is the operating frequency of the thyristor, is the turn-on time of the thyristor, is the turn-off time of the thyristor.

10. A system for protecting a converter valve against abnormal junction temperature by adjusting the water cooling flow rate using the method according to any one of claims 1 to 9, comprising a measurement module, a comprehensive junction temperature abnormality index calculation module, a maximum flow rate calculation module, a loss function establishment module, and a flow rate adjustment module, characterized in that: Measuring module: used to measure the junction temperature of each flow element of the controllable phase-changing valve in real time using a temperature sensor, the flow element including a thyristor and an IGBT, and measure the inlet and outlet water temperatures of the water cooling system; Comprehensive junction temperature abnormality index calculation module: used to calculate the comprehensive junction temperature abnormality index of each flow element according to the junction temperature and the junction temperature change rate; if there is a flow element whose comprehensive junction temperature abnormality index is greater than or equal to the set corresponding flow element index threshold, then obtain the thermal resistance curve between the flow rate and the thermal resistance from the radiator to the cooling medium of the water cooling system through simulation; Maximum flow rate calculation module: Combines the resistance along the water cooling system and the local resistance, and calculates the maximum flow rate of the water cooling system according to the rated power of the water cooling system; Loss function establishment module: establishes a loss function combining the heat-related losses of the flow element corresponding to the moment, the thermal resistance from the radiator to the cooling medium of the water cooling system, and the inlet and outlet water temperatures; Flow rate regulation module: With the maximum flow rate as the constraint, the flow rate is continuously adjusted. After each adjustment, the thermal resistance from the radiator to the cooling medium of the water cooling system corresponding to the adjusted flow rate is obtained by querying the thermal resistance curve. After each adjustment, the heat-related losses of the corresponding flow-through elements are calculated, thereby calculating the loss function after each adjustment and adjusting the flow rate until the loss function reaches the minimum.

Images