New energy vehicle-mounted DC-DC module temperature rise detection and heat dissipation method and system

Abstract

The application relates to the field of automobile technology, in particular to a new energy automobile vehicle-mounted DC-DC module temperature rise detection and heat dissipation method and system, which comprises the following steps: providing a DC-DC power module, which comprises a sealed shell and a heat dissipation fan, and a first temperature sensing unit and a second temperature sensing unit are arranged on the air inlet side and the air outlet side of the heat dissipation fan respectively; obtaining a first temperature and a second temperature; obtaining an effective temperature difference value through difference processing to form a temperature difference control system; if the second temperature is greater than or equal to a preset temperature threshold, the heat dissipation fan is forcibly started to form an absolute temperature control system. The method improves the prior art which takes a single absolute temperature as the basis for starting and stopping the fan; when the absolute temperature fluctuates near the starting threshold, the fan is prone to frequent starting and stopping; when the ambient temperature is close to or reaches the starting threshold, even if the DC-DC module is in a light load or shutdown state and the heat dissipation fins have no substantial heat load, the fan will still be started due to the high ambient temperature, thereby causing the problem of invalid operation.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, specifically to a method and system for detecting and dissipating the temperature rise of an onboard DC-DC module in a new energy vehicle. Background Technology

[0002] With the rapid development of electric and hybrid vehicles, the power density and heat generation of on-board DC-DC converters (also known as DC-DC power modules), as core components connecting high-voltage power batteries and low-voltage electrical equipment, are continuously increasing. To achieve dust and water resistance, they typically adopt a fully sealed housing structure, integrating and sealing electronic components such as transformers and diodes within the housing to prevent corrosion from the external environment.

[0003] In terms of heat dissipation path, the sealed housing restricts the direct flow of internal air to the external environment, so that the heat generated by the heat-generating element must be conducted to the housing through the thermally conductive silicone pad, and then dissipated into the surrounding air by the heat dissipation fins set on the outer surface of the housing. A cooling fan is installed on the outer wall of the housing to blow the outside air towards the heat dissipation fins. The forced airflow accelerates the air convection on the surface of the fins, thereby carrying away the heat on the fins.

[0004] In existing technologies, absolute temperature is usually used as the basis for controlling the start and stop of cooling fans. Specifically, a temperature sensor is used to detect the internal temperature of the DC-DC converter or the ambient temperature. When the temperature reaches a preset threshold, the fan is started, and when the temperature drops to another threshold, the fan is stopped.

[0005] However, when the collected absolute temperature fluctuates around the fan start threshold, it can easily cause the fan to start and stop frequently. When the ambient temperature is close to or reaches the fan start threshold (or the collected absolute temperature is close to the ambient temperature but exceeds the fan start threshold), even if the DC-DC module is under light load or shut down and the heat sink does not have a substantial heat load, the fan will still start due to the high ambient temperature. At this time, the fan cannot remove effective heat, resulting in ineffective operation, consuming power and accelerating fan wear. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method and system for detecting and dissipating the temperature rise of a DC-DC module in a new energy vehicle, so as to improve the existing technology that uses a single absolute temperature as the basis for fan start-stop. When the absolute temperature fluctuates near the start-up threshold, it is easy to cause the fan to start and stop frequently. When the ambient temperature is close to or reaches the start-up threshold, even if the DC-DC module is in a light load or off state and the heat sink fins have no substantial heat load, the fan will still start due to the high ambient temperature, resulting in ineffective operation.

[0007] This invention is achieved through the following technical solution: A method for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle, comprising the following steps: S1: A DC-DC power module is provided, which includes a sealed housing and a cooling fan fixedly installed on the outer wall of the sealed housing. The outer wall of the sealed housing is provided with a plurality of heat dissipation fins around the cooling fan. The cooling fan blows the outside air toward the heat dissipation fins. A first temperature sensing unit and a second temperature sensing unit are respectively provided on the air inlet side and the air outlet side of the cooling fan. S2: Obtain the first temperature detected by the first temperature sensing unit and the second temperature detected by the second temperature sensing unit; S3: The difference between the second temperature and the first temperature is taken as the measured temperature difference value, and the measured temperature difference value is subtracted from the preset baseline temperature difference to obtain the effective temperature difference value; S4: If the effective temperature difference value is greater than or equal to the preset temperature difference start threshold, and the duration reaches the preset delay, then control the cooling fan to start and run for a calibration period. S5: After the calibration period ends, if the effective temperature difference value is less than the temperature difference start threshold but greater than or equal to the preset temperature difference stop threshold, then the calibration period is reset and the cooling fan continues to run; otherwise, the cooling fan is controlled to stop, thus forming a temperature difference control system. S6: During the execution of S2 to S5, if the second temperature is greater than or equal to the preset temperature threshold, the cooling fan is forcibly started to form an absolute temperature control system, and the absolute temperature control system has a higher priority than the temperature difference control system.

[0008] Furthermore, in step S6, the temperature threshold of the absolute temperature control system includes a temperature warning threshold, a temperature protection threshold, and a temperature shutdown threshold. When the second temperature is greater than or equal to the temperature warning threshold, the cooling fan is controlled to run at full speed, and the DC-DC power module operates normally. When the second temperature is greater than or equal to the temperature protection threshold, the cooling fan is controlled to run at full speed and the output power of the DC-DC power module is reduced. When the second temperature is greater than or equal to the temperature shutdown threshold, the cooling fan is controlled to run at full speed and the DC-DC power module is shut down. The values ​​of the temperature warning threshold, temperature protection threshold, and temperature shutdown threshold increase sequentially.

[0009] Furthermore, the temperature warning threshold is 60-70℃, the temperature protection threshold is 80-90℃, and the temperature shutdown threshold is 95-105℃.

[0010] Furthermore, the absolute temperature control system will be deactivated when the following conditions are met simultaneously: The second temperature drops from above the temperature warning threshold to below the temperature warning threshold minus the preset hysteresis temperature; The effective temperature difference value is less than the temperature difference stopping threshold.

[0011] Furthermore, the preset hysteresis temperature is 3-5℃.

[0012] Furthermore, in step S3, the preset baseline temperature difference is 1-3℃; In step S4, the temperature difference start threshold is 8-10℃, the preset delay is 20-60 seconds, and the calibration duration is 3-10 minutes. In step S5, the temperature difference stopping threshold is 4-5℃.

[0013] Furthermore, in step S5, the rate of decrease of the effective temperature difference is monitored. When the rate of decrease exceeds a preset rate of decrease threshold, the remaining duration of this calibration is shortened to 50%.

[0014] Furthermore, the descent rate threshold is 1-2 °C / min.

[0015] A system for detecting and dissipating heat from the temperature rise of the on-board DC-DC module in the aforementioned new energy vehicle includes: DC-DC power module, including a sealed housing and a module body integrated within the housing; Several heat dissipation fins are arranged side by side on the outer wall of the housing, and a heat dissipation channel is formed between two adjacent heat dissipation fins. A space for installing a cooling fan is opened in the middle of the multiple heat dissipation fins on the inner side. A cooling fan is fixedly installed on the outer wall of the housing, and blows external air toward the heat dissipation channel through the cooling fan. The first temperature sensing unit is located on the air intake side of the cooling fan and is used to detect the first temperature. The second temperature sensing unit is located on the exhaust side of the cooling fan and is used to detect the second temperature. The control unit is electrically connected to the first temperature sensing unit, the second temperature sensing unit, and the cooling fan, respectively, and is used to receive the first temperature and the second temperature collected by the first temperature sensing unit and the second temperature sensing unit, and to output control commands to the cooling fan.

[0016] Furthermore, the bracket of the cooling fan is provided with support rods extending axially toward the impeller on both the air inlet and air outlet sides, and the first temperature sensing unit and the second temperature sensing unit are respectively fixedly installed by the two support rods. The second temperature sensing unit is a surface-mount negative temperature coefficient thermistor. After the cooling fan is fixedly installed on the outer wall of the housing, the negative temperature coefficient thermistor is tightly attached to the outer wall of the housing.

[0017] The beneficial effects of this invention are as follows: This invention relates to a method and system for detecting and dissipating the temperature rise of a DC-DC module in a new energy vehicle. By collecting temperatures on both the intake and exhaust sides of the same cooling fan and calculating the difference between them, the system can reflect the heat load on the cooling fins under the current operating conditions. When the DC-DC module is lightly loaded or shut down, the cooling fins have no substantial heat load, resulting in a small temperature difference between the intake and exhaust sides. If the effective temperature difference is lower than the start-up threshold, the fan will not start, thus avoiding the problem of the fan being accidentally triggered due to high ambient temperature. When the load on the DC-DC module increases and the temperature of the cooling fins rises, the airflow passing through the fins is heated, the temperature on the exhaust side rises, and the temperature difference increases until the effective temperature difference reaches the start-up threshold, at which point the fan starts. At this time, the fan can effectively remove the heat from the fins.

[0018] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0019] Figure 1 This is a flowchart of an embodiment of the present invention; Figure 2 This is a three-dimensional structural diagram of an embodiment of the present invention; Figure 3 This is a schematic diagram of the planar structure of an embodiment of the present invention; Figure 4 This is an application model diagram of an embodiment of the present invention.

[0020] In the diagram: 1. Housing; 2. Heat dissipation fins; 21. Heat dissipation channel; 3. Cooling fan; 31. Support rod; 4. First temperature sensing unit; 5. Second temperature sensing unit. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the above description of the present invention, it should be noted that the terms "one side," "the other side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use. These terms are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, terms such as "identical" do not imply that components must be absolutely identical; minor differences are permissible. The term "perpendicular" simply means that the positional relationship between components is more perpendicular than "parallel," not that the structure must be perfectly perpendicular; a slight tilt is acceptable.

[0026] Please see Figure 1-4 This invention provides a technical solution: a method for detecting and dissipating the temperature rise of an on-board DC-DC module in a new energy vehicle, comprising the following steps: S1: A DC-DC power module is provided, which includes a sealed housing 1 and a cooling fan 3 fixedly installed on the outer wall of the sealed housing 1. A plurality of heat dissipation fins 2 are provided on the outer wall of the sealed housing 1 around the cooling fan 3. The cooling fan 3 blows the outside air toward the cooling fins 2. A first temperature sensing unit 4 and a second temperature sensing unit 5 are respectively provided on the air inlet side and the air outlet side of the cooling fan 3. S2: Obtain the first temperature detected by the first temperature sensing unit 4 and the second temperature detected by the second temperature sensing unit 5; S3: The difference between the second temperature and the first temperature is taken as the measured temperature difference value, and the measured temperature difference value is subtracted from the preset baseline temperature difference to obtain the effective temperature difference value; S4: If the effective temperature difference value is greater than or equal to the preset temperature difference start threshold and the duration reaches the preset delay, then control the cooling fan 3 to start and run for a calibration period. S5: After the calibration period ends, if the effective temperature difference value is less than the temperature difference start threshold but greater than or equal to the preset temperature difference stop threshold, then the calibration period is reset and the cooling fan 3 continues to run; otherwise, the cooling fan 3 is controlled to stop, thus forming a temperature difference control system. S6: During the execution of S2 to S5, if the second temperature is greater than or equal to the preset temperature threshold, the cooling fan 3 is forcibly started to form an absolute temperature control system, and the absolute temperature control system has a higher priority than the temperature difference control system.

[0027] In this solution, by collecting temperatures on the intake and exhaust sides of the same cooling fan 3 and calculating the difference between them, the heat load of the heat sink 2 under the current operating conditions can be reflected. When the DC-DC module is lightly loaded or shut down, the heat sink 2 has no substantial heat load, resulting in a small temperature difference between the intake and exhaust sides. If the effective temperature difference is lower than the start-up threshold, the fan will not start, thus avoiding the problem of the fan being accidentally triggered due to high ambient temperature. When the load of the DC-DC module increases and the temperature of the heat sink 2 rises, the airflow flowing through the fins is heated, the temperature on the exhaust side rises, and the temperature difference increases until the effective temperature difference reaches the start-up threshold, at which point the fan starts. At this time, the fan can effectively remove the heat from the fins.

[0028] The temperature difference start threshold is greater than the temperature difference stop threshold, creating a hysteresis range between the two. Within this range, the fan can continue to run after starting, and will only stop when the effective temperature difference value drops below the temperature difference stop threshold. This avoids frequent fan start-stop caused by temperature fluctuations around a single threshold.

[0029] Furthermore, the preset temperature threshold in step S6 serves as the trigger condition for the absolute temperature control system. When the second temperature reaches this threshold, the fan is forcibly activated regardless of the state of the temperature difference control system, ensuring a safety net even when the thermal inertia of the heat sink 2 causes a lag in the temperature difference response or an abnormal temperature difference signal. For example, if the threshold is set to a relatively high temperature value (90℃), the temperature difference control system operates below 90℃, and only when a significant temperature gradient (temperature difference) is formed between the casing 1 and the surrounding air can the cooling fan 3 be triggered to start, thus reducing the trigger sensitivity of the cooling fan 3. Even if the temperature difference control system fails and the temperature on the casing 1 rises due to heat accumulation, the absolute temperature control system can be connected to control the cooling fan 3 to start for forced cooling. This balances on-demand cooling with safety protection.

[0030] The absolute temperature control system has a higher priority than the temperature difference control system. Even if the temperature difference between the casing 1 (second temperature) and the ambient temperature (first temperature) is small in a high-temperature environment (such as a temperature difference of 2-3 degrees), the cooling fan 3 can still be forcibly started through the absolute temperature control system.

[0031] In this embodiment: in step S6, the temperature threshold of the absolute temperature control system includes a temperature warning threshold, a temperature protection threshold, and a temperature shutdown threshold; When the second temperature is greater than or equal to the temperature warning threshold, the cooling fan 3 is controlled to run at full speed, and the DC-DC power module operates normally. When the second temperature is greater than or equal to the temperature protection threshold, the cooling fan 3 is controlled to run at full speed and the output power of the DC-DC power module is reduced. When the second temperature is greater than or equal to the temperature shutdown threshold, control the cooling fan 3 to run at full speed and shut down the DC-DC power module. The values ​​of the temperature warning threshold, temperature protection threshold, and temperature shutdown threshold increase sequentially.

[0032] In this solution, the absolute temperature control system is further divided into three levels: temperature warning threshold, temperature protection threshold, and temperature shutdown threshold. When the second temperature reaches the temperature warning threshold, the fan is forcibly started. At this time, the DC-DC module can still maintain normal output, which is a warning-type heat dissipation. When the second temperature continues to rise to the temperature protection threshold, the fan runs at full speed and reduces the module's output power. By reducing heat generation, the temperature is suppressed from continuing to rise, reducing the risk of devices aging faster due to long-term exposure to high temperatures. When the second temperature reaches the temperature shutdown threshold, the fan runs at full speed and shuts down the DC-DC module to prevent power devices from being damaged due to overheating.

[0033] The three threshold levels increase sequentially, forming a progressive safety defense line from early warning to protection to shutdown. Each action is based on the premise that the fan is running at full speed to make the most of the existing heat dissipation capacity.

[0034] This graded protection mechanism and the temperature difference control system are independent of each other but also work together. The temperature difference control system is responsible for heat dissipation as needed under normal operating conditions, while the absolute temperature control system is responsible for safety backup under abnormal operating conditions. The two can switch seamlessly through priority relationship.

[0035] In this embodiment: the temperature warning threshold is 60-70℃, the temperature protection threshold is 80-90℃, and the temperature shutdown threshold is 95-105℃.

[0036] In this solution, the temperature warning threshold is set at 60-70℃, which can start the fan in advance when the junction temperature of the device still has a margin, giving time for subsequent heat dissipation; the temperature protection threshold is set at 80-90℃, which can trigger load reduction near the upper limit of the long-term operating temperature of the device, suppressing thermal aging; and the temperature shutdown threshold is set at 95-105℃, which can cut off the output when the device approaches the extreme temperature, reducing the risk of permanent damage.

[0037] In this embodiment, the absolute temperature control system is exited when the following conditions are met simultaneously: The second temperature drops from above the temperature warning threshold to below the temperature warning threshold minus the preset hysteresis temperature; The effective temperature difference value is less than the temperature difference stopping threshold.

[0038] In this scheme, the second temperature needs to fall from above the temperature warning threshold to below the temperature warning threshold minus the preset hysteresis temperature, and the effective temperature difference value is less than the temperature difference stop threshold. The former avoids temperature oscillation near the warning threshold through hysteresis design, while the latter ensures that the temperature difference control system has also determined that no further heat dissipation is needed when exiting the absolute temperature control system. Through the combined effect of these two conditions, the switching between the absolute temperature control system and the temperature difference control system is natural and does not conflict.

[0039] In this embodiment, the preset hysteresis temperature is 3-5℃.

[0040] In this design, the hysteresis range is adapted to the measurement accuracy and temperature fluctuation amplitude of the temperature sensor in the vehicle environment. If the hysteresis is too small, it cannot effectively suppress oscillations near the threshold; if the hysteresis is too large, it will cause a delay in the exit of the absolute temperature control system and an unnecessary extension of the fan running time. A hysteresis of 3-5℃ can ensure switching stability while allowing the fan to exit the absolute temperature control system in a timely manner after the temperature drops to a safe range, and return to the normal regulation of the temperature difference control system.

[0041] Among them, automotive-grade NTC thermistors used for fin temperature measurement in automotive DC-DC converters typically have a nominal accuracy in the range of ±0.2℃ to ±1℃. For example, TDK's L862 series has a tolerance of ±1%. Each of the two temperature sensing units has its own measurement error, and the combined uncertainty is at least ±0.4℃ to ±2℃. If the hysteresis is lower than this order of magnitude, the normal measurement noise near the threshold temperature difference reading is sufficient to trigger a state reversal, causing the hysteresis to lose its anti-oscillation function. The lower limit of 3℃ provides a margin of approximately 1.5 to 7 times for sensor accuracy, allowing the hysteresis to stably cover the measurement noise.

[0042] In this embodiment: in step S3, the preset baseline temperature difference is 1-3℃; In step S4, the temperature difference start threshold is 8-10℃, the preset delay is 20-60 seconds, and the calibration duration is 3-10 minutes. In step S5, the temperature difference stopping threshold is 4-5℃.

[0043] In this scheme, the preset baseline temperature difference of 1-3℃ reflects the inherent temperature difference between the intake and exhaust sides due to differences in installation location and environment after the DC-DC module is not working and reaches thermal stability. This is subtracted from the measured temperature difference value so that the effective temperature difference value more accurately reflects the actual heat load of the heat sink 2.

[0044] The temperature difference start threshold of 8-10℃ means that the fan can only be triggered when the temperature difference between the first and second collected temperatures reaches a certain value (the DC-DC module generates a heat load sufficient to make the temperature rise reach this range), thus reducing the probability of false triggering under light load conditions.

[0045] The preset delay of 20-60 seconds is used to filter out instantaneous temperature fluctuations caused by transient load changes, and to prevent the fan from starting erroneously due to short-term temperature pulses.

[0046] The calibration time is set to 3-10 minutes to ensure that the fan runs for at least that duration each time it starts. Even if the temperature difference temporarily decreases during operation due to airflow, the fan will not stop immediately, thereby suppressing frequent starts and stops, reducing the frequency of fan starts, and providing continuous heat dissipation.

[0047] The temperature difference stopping threshold is 4-5℃, which forms a sufficient hysteresis width (4-5℃) between it and the temperature difference starting threshold, further ensuring that the fan only stops after the heat dissipation demand has indeed disappeared.

[0048] In this embodiment: In step S5, the rate of decrease of the effective temperature difference is monitored. When the rate of decrease exceeds the preset rate of decrease threshold, the remaining duration of this calibration is shortened to 50%.

[0049] In this embodiment, the descent rate threshold is 1-2℃ / minute.

[0050] In this solution, the calibration duration serves as a protective measure to prevent frequent start-stop cycles. If the cooling demand has indeed disappeared, mechanically waiting for the calibration duration to run out would lead to unnecessary continuous fan operation. This mechanism complements the calibration duration; the calibration duration provides a lower limit protection against oscillation, while the rate of decrease judgment provides the flexibility to exit early.

[0051] When the effective temperature difference decreases at a rate exceeding a preset threshold (decrease rate threshold), it indicates that the heat load on the heat sink fin 2 is decreasing rapidly. At this point, shortening the remaining duration of this calibration period can allow the fan to stop earlier without frequent start-stop cycles, thereby further reducing power consumption and fan wear.

[0052] A system for detecting and dissipating heat from the temperature rise of the on-board DC-DC module in the aforementioned new energy vehicle includes: A DC-DC power module includes a sealed housing 1 and a module body integrated within the housing 1; Several heat dissipation fins 2 are arranged side by side on the outer wall of the housing 1, and a heat dissipation channel 21 is formed between two adjacent heat dissipation fins 2. A space for installing a cooling fan 3 is opened in the middle of the multiple heat dissipation fins 2 on the inner side. Cooling fan 3 is fixedly installed on the outer wall of the housing 1, and blows the outside air toward the heat dissipation channel 21 through cooling fan 3; The first temperature sensing unit 4 is disposed on the air intake side of the cooling fan 3 and is used to detect the first temperature; The second temperature sensing unit 5 is located on the air outlet side of the cooling fan 3 and is used to detect the second temperature. The control unit is electrically connected to the first temperature sensing unit 4, the second temperature sensing unit 5 and the cooling fan 3 respectively, and is used to receive the first temperature and the second temperature collected by the first temperature sensing unit 4 and the second temperature sensing unit 5, and output control commands to the cooling fan 3.

[0053] In this solution, by opening a space in the middle of multiple heat dissipation fins 2 on the inner side for installing the cooling fan 3, the cooling fan 3 can be embedded in the fin array, and the airflow blown out by the fan can directly enter the heat dissipation channel 21, shortening the airflow path and reducing wind pressure loss.

[0054] The first temperature sensing unit 4 is located on the fan intake side, and the second temperature sensing unit 5 is located on the fan exhaust side. Both are located on the fan bracket, and their installation positions are fixed and consistent, which helps to ensure the repeatability and consistency of temperature difference measurement.

[0055] The control unit is electrically connected to two temperature sensing units and a fan, respectively, to receive temperature signals and output control commands, thus forming a complete closed-loop control system.

[0056] In this embodiment: the bracket of the cooling fan 3 is provided with support rods 31 extending axially toward the impeller on both the air inlet side and the air outlet side, and the first temperature sensing unit 4 and the second temperature sensing unit 5 are respectively fixedly installed by the two support rods 31. The second temperature sensing unit 5 is a surface-mount negative temperature coefficient thermistor. After the cooling fan 3 is fixedly installed on the outer wall of the housing 1, the negative temperature coefficient thermistor is tightly attached to the outer wall of the housing 1.

[0057] In this design, both support rods 31 extend axially toward the impeller and are respectively fixedly mounted with two temperature sensing units. This maintains a certain axial distance between the temperature sensing units and the fan impeller, reducing the interference of airflow disturbance and motor heat generation on temperature measurement caused by impeller rotation. Simultaneously, the first temperature sensing unit 4 and the second temperature sensing unit 5 are both fixedly mounted on the fan bracket for easy assembly onto the housing 1 (DC-DC module). Furthermore, the relative positions of the two temperature sensing units are easily kept consistent during mass production, which is beneficial for baseline temperature difference calibration and consistency of temperature difference measurement.

[0058] The second temperature sensing unit 5 uses a surface-mount negative temperature coefficient thermistor, which is tightly attached to the outer wall of the housing 1 after the fan is installed on the outer wall of the housing 1. This allows the second temperature sensing unit 5 to simultaneously sense the temperature of the outer wall of the housing 1 and the airflow temperature on the exhaust side. After the thermistor is tightly attached to the outer wall of the housing 1, its measurement value reflects the actual temperature of the surface of the housing 1 more accurately. Since the temperature of the housing 1 is highly correlated with the temperature of the heat sink 2, it can more accurately reflect the heat load of the heat sink 2.

[0059] 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 it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle, characterized in that: Includes the following steps: S1: A DC-DC power module is provided, which includes a sealed housing (1) and a cooling fan (3) fixedly installed on the outer wall of the sealed housing (1). The outer wall of the sealed housing (1) is provided with a plurality of heat dissipation fins (2) around the cooling fan (3). The cooling fan (3) blows the outside air towards the heat dissipation fins (2). A first temperature sensing unit (4) and a second temperature sensing unit (5) are respectively provided on the air inlet side and the air outlet side of the cooling fan (3). S2: Obtain the first temperature detected by the first temperature sensing unit (4) and the second temperature detected by the second temperature sensing unit (5); S3: The difference between the second temperature and the first temperature is taken as the measured temperature difference value, and the measured temperature difference value is subtracted from the preset baseline temperature difference to obtain the effective temperature difference value; S4: If the effective temperature difference value is greater than or equal to the preset temperature difference start threshold and the duration reaches the preset delay, then control the cooling fan (3) to start and run for a calibration period. S5: After the calibration time ends, if the effective temperature difference value is less than the temperature difference start threshold but greater than or equal to the preset temperature difference stop threshold, then the calibration time is reset and the cooling fan (3) continues to run; otherwise, the cooling fan (3) is controlled to stop, thus forming a temperature difference control system. S6: During the execution of S2 to S5, if the second temperature is greater than or equal to the preset temperature threshold, the cooling fan (3) is forcibly started to form an absolute temperature control system, and the absolute temperature control system has a higher priority than the temperature difference control system.

2. The method for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle according to claim 1, characterized in that: In step S6, the temperature threshold of the absolute temperature control system includes a temperature warning threshold, a temperature protection threshold, and a temperature shutdown threshold. When the second temperature is greater than or equal to the temperature warning threshold, the cooling fan (3) is controlled to run at full speed, and the DC-DC power module operates normally. When the second temperature is greater than or equal to the temperature protection threshold, the cooling fan (3) is controlled to run at full speed and the output power of the DC-DC power module is reduced; When the second temperature is greater than or equal to the temperature shutdown threshold, the cooling fan (3) is controlled to run at full speed and the DC-DC power module is shut off. The values ​​of the temperature warning threshold, temperature protection threshold, and temperature shutdown threshold increase sequentially.

3. The method for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle according to claim 2, characterized in that: The temperature warning threshold is 60-70℃, the temperature protection threshold is 80-90℃, and the temperature shutdown threshold is 95-105℃.

4. The method for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle according to claim 2, characterized in that: The absolute temperature control system will be deactivated when the following conditions are met simultaneously: The second temperature drops from above the temperature warning threshold to below the temperature warning threshold minus the preset hysteresis temperature; The effective temperature difference value is less than the temperature difference stopping threshold.

5. The method for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle according to claim 4, characterized in that: The preset hysteresis temperature is 3-5℃.

6. The method for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle according to claim 1, characterized in that: In step S3, the preset baseline temperature difference is 1-3℃; In step S4, the temperature difference start threshold is 8-10℃, the preset delay is 20-60 seconds, and the calibration duration is 3-10 minutes. In step S5, the temperature difference stopping threshold is 4-5℃.

7. The method for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle according to claim 1, characterized in that: In step S5, the rate of decrease of the effective temperature difference is monitored. When the rate of decrease exceeds a preset rate of decrease threshold, the remaining duration of this calibration is shortened to 50%.

8. The method for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle according to claim 7, characterized in that: The descent rate threshold is 1-2℃ / minute.

9. A system for detecting and dissipating heat from the temperature rise of an on-board DC-DC module in a new energy vehicle as described in any one of claims 1-8, characterized in that: include: The DC-DC power module includes a sealed housing (1) and a module body integrated within the housing (1); Several heat dissipation fins (2) are arranged side by side on the outer wall of the housing (1), and a heat dissipation channel (21) is formed between two adjacent heat dissipation fins (2). A space for installing a cooling fan (3) is opened in the middle of the multiple heat dissipation fins (2) on the inner side. A cooling fan (3) is fixedly installed on the outer wall of the housing (1) and blows the outside air to the heat dissipation channel (21) through the cooling fan (3). The first temperature sensing unit (4) is located on the air intake side of the cooling fan (3) and is used to detect the first temperature; The second temperature sensing unit (5) is located on the exhaust side of the cooling fan (3) and is used to detect the second temperature. The control unit is electrically connected to the first temperature sensing unit (4), the second temperature sensing unit (5) and the cooling fan (3) respectively, and is used to receive the first temperature and the second temperature collected by the first temperature sensing unit (4) and the second temperature sensing unit (5), and output control commands to the cooling fan (3).

10. The temperature rise detection and heat dissipation system for on-board DC-DC modules in new energy vehicles according to claim 9, characterized in that: The bracket of the cooling fan (3) is provided with support rods (31) extending axially toward the impeller on both the air inlet side and the air outlet side, and the first temperature sensing unit (4) and the second temperature sensing unit (5) are fixedly installed by the two support rods (31). The second temperature sensing unit (5) is a surface-mount negative temperature coefficient thermistor. After the cooling fan (3) is fixedly installed on the outer wall of the housing (1), the negative temperature coefficient thermistor is tightly attached to the outer wall of the housing (1).

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