A dust removal control method for a new energy truck heat dissipation fan

Abstract

The application discloses a dust removal control method for a new energy truck heat dissipation fan, which comprises the following steps: taking the FCU and the whole vehicle power-on linkage as the starting point, first performing one-time reverse dust removal after the power supply, communication, drive and sensing link self-inspection are qualified; then, based on the segmented threshold and linear mapping of the motor temperature and the controller temperature, the PWM is adjusted in real time, the duty cycle is constrained by the change rate and the positive / negative rotation switching is pre-stopped for buffering; when the temperature is out of limit, full-load heat dissipation is preferred and the power is limited in cooperation with the MCU; at the same time, the RTC accumulates the positive rotation working hours, and the periodic dust removal of smooth speed reduction-stop-reverse-stop-mapping recovery is performed in the non-emergency heat dissipation window. The method solves the problems that the dust in the air duct is difficult to be cleaned online under high dust working conditions, the heat dissipation control is extensive, and the overheating risk is high, and achieves the technical effects of stable air volume and heat exchange efficiency, reduced energy consumption and NVH, and decreased maintenance frequency and failure rate.

Description

Technical Field

[0001] This invention relates to the technical field of dust removal for new energy trucks, and more particularly to a dust control method for cooling fans of new energy trucks. Background Technology

[0002] As a clean and efficient means of transportation, new energy trucks are increasingly used in harsh environments with high dust levels, such as mines and construction sites. Under such conditions, the vehicle's electronic cooling fans easily attract large amounts of dust and fine debris, gradually forming grime on the fan blades, motor, and radiator surfaces. As operating time increases, dust accumulation not only significantly increases the fan's rotational resistance, leading to increased motor load and reduced energy efficiency, but may even cause the fan motor to burn out due to overheating, seriously threatening the vehicle's stable operation and service life. Although current fan control methods typically use fixed speed or pulse width modulation (PWM) to adjust the speed to meet basic cooling needs, they generally lack active dust removal functions for dust accumulation, relying solely on periodic manual maintenance and cleaning. This is not only costly and inefficient, but also fails to address the dust accumulation problem in real time during vehicle operation.

[0003] CN103541923A discloses a dust removal control device and method for an automotive front-end cooling module, which controls the fan to turn on / off through a simple timer and a judge to achieve dust removal. However, the control logic of this scheme is relatively simple and lacks real-time consideration of vehicle operating conditions, motor status and environmental factors. Its dust removal strategy cannot adapt to complex actual operating environments, resulting in poor dust removal effect or dust removal when unnecessary, increasing ineffective energy consumption.

[0004] CN104564769A discloses an automatic dust removal control method based on computer fan speed, which only triggers the reverse dust removal function when the fan's forward rotation speed is lower than a preset value. This passive triggering mechanism based on performance degradation means that the dust removal operation is only started after the fan performance has been severely affected, making it impossible to achieve early prevention and regular maintenance. Furthermore, it fails to fully consider the dust removal needs under different working conditions, thus limiting its applicability when facing the complex operating environment of new energy trucks.

[0005] Existing technologies generally lack a comprehensive intelligent dust removal control strategy that integrates vehicle power-on self-test, real-time dynamic temperature adjustment, and periodic dust removal based on continuous working time. Therefore, this invention aims to provide a dust removal control method for cooling fans of new energy trucks. By implementing intelligent fan forward and reverse rotation control and safety protection strategies under various conditions such as vehicle power-on, dynamic temperature changes, and continuous operation, this invention effectively solves the problems of passivity, lack of intelligence, and incomplete control in existing fan dust removal methods. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section, as well as in the abstract and title of the present application, to avoid obscuring the purpose of this section, the abstract and title of the invention. Such simplifications or omissions shall not be used to limit the scope of the present invention.

[0007] In view of the aforementioned existing problems, the present invention is proposed.

[0008] To solve the above technical problems, the present invention provides the following technical solution: S1. When the key switch is in the ON position or the vehicle controller VCU sends a high-voltage power-on completion signal, the fan controller FCU is woken up by the low-voltage power supply and establishes CAN communication with the VCU and MCU to receive the vehicle enable command; if the vehicle is in fault protection mode, it remains in standby until the fault is cleared.

[0009] S2. Within the preset time limit, the power supply voltage range detection, communication link heartbeat detection, drive power device continuity detection and temperature sensor range detection are completed sequentially. If the self-test passes, a self-test pass signal is sent to the VCU and the process proceeds to the next step. If the self-test fails, the process is downgraded or locked according to the fault level and a fault code is reported.

[0010] S3. After the self-test passes, regardless of the current temperature, a reverse dust removal is forcibly performed. The reverse dust removal is achieved by switching the motor phase sequence. The duty cycle is increased from 0% to the preset duty cycle in a step-by-step manner and the motor runs for a preset time. During this period, the motor current is monitored and stall protection is implemented. After the end of the process, the motor is stopped to allow the dust to settle.

[0011] S4. Collect motor temperature and controller temperature via CAN. When the motor temperature is less than or equal to the first threshold and the controller temperature is less than or equal to the first threshold, the fan does not start and enters low power monitoring. Update the temperature according to the set cycle and reduce the communication frequency.

[0012] S5. When the motor temperature or the controller temperature falls into the range of (first threshold, second threshold), the target duty cycle is obtained according to the temperature-duty cycle linear mapping, and the target is updated when the temperature change reaches the set magnitude.

[0013] S6. When the motor temperature is greater than or equal to the second threshold or the controller temperature is greater than or equal to the second threshold, the fan duty cycle is immediately switched to full load and kept at the highest priority until the temperature drops back to the safe range. When the full load operation reaches the set time and the temperature does not drop back to the safe threshold, a high temperature alarm is reported. When the temperature reaches the over-temperature limit, a power limiting request is initiated to the MCU.

[0014] S7. The forward rotation working time is accumulated by the built-in clock of FCU. When the accumulated time reaches the period threshold, it is marked that dust removal needs to be performed. Under the condition that it is not in S6, the speed is smoothly reduced to 0, stopped, reversed according to the preset duty cycle, stopped, and the sequence of the corresponding duty cycle before dust removal is restored according to the temperature-duty cycle mapping to perform periodic reverse dust removal.

[0015] In this system, any forward / reverse switching is preceded by a stop interval, and any change in duty cycle is limited by the maximum slope to reduce electrical and mechanical shocks.

[0016] As a preferred embodiment of the dust removal control method for a cooling fan of a new energy truck according to the present invention, step S2 includes:

[0017] The acceptable range for power supply voltage testing is 10.5V to 32V;

[0018] A communication link heartbeat timeout is considered a communication failure.

[0019] The continuity of drive power devices is detected by injecting a microcurrent to confirm open / short circuits.

[0020] The temperature sensor has a range of -40℃ to 150℃ and the initial power-on value should be within ±5℃ of the ambient temperature.

[0021] When the sensor drifts, it is determined to be a minor fault, and degraded operation is allowed;

[0022] When the drive circuit is short-circuited, it is determined to be a serious fault, the fan is locked and the fault indicator is illuminated.

[0023] As a preferred embodiment of the dust removal control method for cooling fans of new energy trucks according to the present invention, the reverse dust removal is performed according to the following parameters:

[0024] The reverse rotation direction is opposite to the forward rotation direction of heat dissipation.

[0025] The duty cycle is set to 40%, and the duration is set to 15 seconds.

[0026] The duty cycle increases from 0% to 40% in a stepped manner, with a step time of not less than 200ms;

[0027] If the motor current exceeds 150% of the rated value during the reversal process, the machine should be stopped immediately and the dust removal stall fault should be recorded.

[0028] After the reversal is completed, the rotation should stop for no less than 2 seconds.

[0029] As a preferred embodiment of the dust control method for the cooling fan of a new energy truck described in this invention, the low power consumption monitoring cycle is no higher than 5 seconds / time, and the CAN message frequency is reduced to reduce bus occupation and power consumption.

[0030] As a preferred embodiment of the dust removal control method for cooling fans of new energy trucks according to the present invention, step S5 adopts the following linear mapping:

[0031] The first threshold is 60°C, the second threshold is 80°C, and the duty cycle is calculated using the following formula:

[0032]

[0033] Where T is temperature. For the target duty cycle, For motor temperature, For controller temperature, The duty cycle at the starting point of the linear mapping. =40%, The duty cycle at the endpoint of the linear mapping. =80%, , At 0, the fan does not start, and the system enters low-power monitoring mode. At that time, full load heat dissipation;

[0034] An update is triggered when the temperature change is ≥2℃ and the duty cycle change rate is less than 5% / second.

[0035] As a preferred embodiment of the dust removal control method for the cooling fan of a new energy truck described in this invention, the threshold for the duration of full-load operation in S6 is 10 minutes. When the full-load operation exceeds 10 minutes and the temperature is still not lower than 75°C, a high temperature alarm is reported. When the temperature reaches the over-temperature limit of 95°C, the MCU is requested to limit the motor output power while maintaining full-load operation.

[0036] As a preferred embodiment of the dust removal control method for cooling fans of new energy trucks described in this invention, the cycle threshold of S7 is defaulted to a cumulative forward rotation of 4 hours, and can be calibrated by the host computer within the range of 1 to 8 hours. The execution sequence of S7 includes: reducing the current duty cycle to 0% at a change rate not exceeding 5% / second, stopping for 10 seconds, reversing the duty cycle to 40% for 15 seconds, stopping again for 10 seconds, and restoring the corresponding duty cycle before dust removal according to the temperature-duty cycle mapping before dust removal.

[0037] As a preferred embodiment of the dust removal control method for the cooling fan of a new energy truck described in this invention, a stop interval is executed before any forward / reverse switching or switching from one stage to another, and the stop interval is not less than 10 seconds; the duty cycle change is limited to a maximum change rate of 5% / second.

[0038] As a preferred embodiment of the dust removal control method for cooling fans of new energy trucks described in this invention, the FCU and VCU / MCU communicate via a CAN bus. The communication includes at least: high voltage power-on completion, self-test pass / fail, fan operation permission, high temperature alarm, over-temperature power limit request, and fault code reporting.

[0039] The beneficial effects of this invention are as follows: By combining multiple strategies such as power-on self-test, forced initial dust removal, temperature-based dynamic heat dissipation control, and periodic dust removal based on working time, this invention forms a complete, intelligent, and proactive closed-loop control method for dust removal and heat dissipation. Compared with existing technologies, this invention not only solves the passive and non-intelligent problems of traditional solutions, but also achieves preventive maintenance of fans, significantly reducing failure rates and manual maintenance costs, and extending the service life of fans and related components. In addition, through refined duty cycle control, safety protection mechanisms, and effective suppression of electrical and mechanical shocks, this method ensures heat dissipation performance while also taking into account the system's energy efficiency, operational stability, and safety. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0041] Figure 1 This is a schematic flowchart of the dust removal control method for a cooling fan of a new energy truck, as shown in this invention. Detailed Implementation

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0043] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort should fall within the scope of protection of this invention.

[0044] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0045] According to an embodiment of the present invention, in combination Figure 1 The flowchart shown illustrates a dust removal control method for cooling fans in new energy trucks, specifically including the following steps:

[0046] S1. When the key switch is in the ON position or the vehicle controller VCU sends a high-voltage power-on completion signal, the fan controller FCU is woken up by the low-voltage power supply and establishes CAN communication with the VCU and MCU to receive the vehicle enable command; if the vehicle is in fault protection mode, it will remain in standby until the fault is cleared.

[0047] S2. Within the preset time limit, the power supply voltage range detection, communication link heartbeat detection, drive power device continuity detection and temperature sensor range detection are completed sequentially. If the self-test passes, a self-test pass signal is sent to the VCU and the process proceeds to the next step. If the self-test fails, the process is downgraded or locked according to the fault level and a fault code is reported.

[0048] S3. After the self-test passes, regardless of the current temperature, a reverse dust removal is forcibly performed. The reverse dust removal is achieved by switching the motor phase sequence. The duty cycle is increased from 0% to the preset duty cycle in a step-by-step manner and the motor runs for a preset time. During this period, the motor current is monitored and stall protection is implemented. After the end, the motor is stopped to allow the dust to settle.

[0049] S4. Collect motor temperature and controller temperature via CAN. When the motor temperature is less than or equal to the first threshold and the controller temperature is less than or equal to the first threshold, the fan will not start and will enter low power monitoring. Update the temperature according to the set period and reduce the communication frequency.

[0050] S5. When the motor temperature or controller temperature falls into the range of (first threshold, second threshold), the target duty cycle is obtained according to the temperature-duty cycle linear mapping, and the target is updated when the temperature change reaches the set magnitude.

[0051] S6. When the motor temperature is greater than or equal to the second threshold or the controller temperature is greater than or equal to the second threshold, the fan duty cycle is immediately switched to full load and kept at the highest priority until the temperature drops back to the safe range. When the temperature does not drop back to the safe threshold after the set time of full load operation, a high temperature alarm is reported. When the temperature reaches the over-temperature limit, a power limiting request is sent to the MCU.

[0052] S7. The forward rotation working time is accumulated by the built-in clock of FCU. When the accumulated time reaches the period threshold, it is marked that dust removal needs to be performed. Under the condition that it is not in S6, the speed is smoothly reduced to 0, stopped, reversed according to the preset duty cycle, stopped, and the sequence of the corresponding duty cycle before dust removal is restored according to the temperature-duty cycle mapping to perform periodic reverse dust removal.

[0053] In this system, any forward / reverse switching is preceded by a stop interval, and any change in duty cycle is limited by the maximum slope to reduce electrical and mechanical shocks.

[0054] It should be noted that by powering on the vehicle via the key or by sending a high-voltage power-on signal from the vehicle controller (VCU), the fan controller (FCU) can be woken up in time and immediately establish CAN communication with the vehicle controller (VCU) and the motor controller (MCU). This step ensures that the fan system enters a controllable state at the initial stage of vehicle startup, providing a solid communication foundation for subsequent self-testing and dust removal operations, avoiding fan control failure due to communication delays or link failures, and significantly improving the system's response speed and reliability.

[0055] Before entering the formal working mode, the system performs self-tests on the power supply voltage, communication link, drive power devices, and temperature sensor sequentially within a preset time limit. This method ensures that the hardware and communication status of the fan system are at a healthy level. When a fault is detected, it can take graded measures according to the fault level (such as degraded operation or lockout) and report the fault code in a timely manner. This not only avoids motor damage or safety accidents that may be caused by operating with faults, but also provides an accurate basis for fault diagnosis and maintenance, greatly improving the stability and maintainability of the system.

[0056] Regardless of the current temperature, a forced reverse dust removal is performed after the self-test passes. This strategy solves the passive problem of traditional fan dust removal solutions that rely on a decrease in heat dissipation performance to trigger the process. The reverse operation, achieved through motor phase sequence switching, can effectively remove stubborn dust that accumulates on the fan blades and radiator surface during vehicle parking or hibernation. It is particularly suitable for vehicles operating in harsh environments such as mines. The stepped duty cycle increase and motor current monitoring effectively avoid the risk of high current surges and stalling during motor startup and dust removal, protecting the motor hardware. At the same time, the stop interval provides valuable time for dust settling, ensuring thorough dust removal.

[0057] When the temperature of both the motor and the controller is below the first threshold, the system does not start the fan but enters a low-power monitoring mode. This step realizes intelligent sleep management of the fan. By reducing the temperature acquisition cycle and CAN communication frequency, this method effectively reduces the power consumption of the system when no heat dissipation is required. Especially in vehicle standby or low-temperature operating environments, it achieves the purpose of energy saving, while still ensuring timely response when the temperature rises.

[0058] Furthermore, by dividing the temperature range into different stages and implementing different control strategies, this method achieves precise and dynamic control of the fan speed. In the intermediate temperature range (S5), a temperature-duty cycle linear mapping adjustment is used to ensure that the fan speed is precisely matched with the actual heat dissipation demand, avoiding unnecessary energy consumption and noise. When the temperature reaches the high temperature threshold (S6), it immediately switches to full-load operation and is given the highest priority to ensure that the fan can work at maximum power under extreme heat dissipation demand, quickly reduce the temperature, and effectively prevent overheating risks. At the same time, safety protection mechanisms such as high temperature alarm and power limit request provide multiple safety guarantees for the vehicle, demonstrating a high degree of intelligence and reliability.

[0059] The FCU's built-in clock accumulates the fan's forward rotation time and triggers dust removal when a preset cycle threshold is reached. This step provides preventative maintenance against fan dust accumulation. It does not rely on a decline in fan performance but is based on a set operating cycle and performs dust removal under non-emergency cooling conditions. The entire dust removal process uses an orderly sequence of smooth deceleration, stopping, and recovery, effectively avoiding mechanical shock and ensuring that the fan can smoothly return to its optimal operating state before dust removal, thereby guaranteeing the long-term efficient operation of the fan.

[0060] The following describes the complete implementation process of a dust control method for a cooling fan of a new energy truck, based on the typical application scenario of new energy trucks in mining areas with high dust and long-term heavy loads. This will enable non-technical personnel to clearly understand the working principle of this technical solution and the technical effects obtained therefrom.

[0061] This embodiment starts with the vehicle being powered on. After the vehicle key is in the ON position or the vehicle controller (VCU) issues a "high voltage power-on complete" message, the fan controller (FCU) is awakened by the low-voltage power supply and automatically enters the standby linkage stage. It should be noted that the reason for linking the vehicle status first is to ensure that the start and stop of the cooling subsystem are consistent with the safety status of the vehicle power supply and drive chain, and to avoid malfunctions when the high-voltage system is not ready or when there is a vehicle-level fault. The FCU establishes a communication handshake with the VCU and MCU (motor controller) through the vehicle controller local area network (CAN bus). If it receives an enable command to "allow fan to work" and the vehicle is not in fault protection mode, the FCU will proceed to the next step. If it is in protection mode (such as high voltage fault), the FCU remains in standby and periodically checks the vehicle status until it is cleared.

[0062] In an optional implementation, low-voltage wake-up includes: when the ignition terminal IG... ON Switching from 0 to 1 (voltage ≥ 9.0 V and held for ≥ 50 ms) or the VCU issuing a "High voltage power-on complete (HV)" message. RDYAfter "=1"), the FCU's PMIC / voltage regulator module is enabled, the MCU exits sleep mode (STOP / SLEEP→RUN), completes clock / watchdog initialization and loads the minimized CAN configuration, and then enters standby mode.

[0063] In an optional implementation, standby linkage includes: periodically pulling the VCU "Allow fan to operate (FAN)" key. EN ") and vehicle fault indicators (SYS)" FLT Establish a subscription to temperature / current / speed messages with the MCU; publish its own heartbeat (FCU). HB Record the power-on timestamp; if the vehicle is in a protection / not ready state, maintain drive enable off (DRV). EN =0), PWM=0, Reverse disabled (REV) LOCK =1), only low-frequency monitoring (≤2 Hz) and fault light management are retained.

[0064] In an optional implementation, the CAN communication handshake adopts a "three-frame mutual recognition + heartbeat maintenance" mechanism: after the FCU powers on, it sends an FCU signal. IDN (Device Identifier / Software Version), waiting for VCU response. ACK With FAN EN And send FCU to the MCU in parallel REQ (Requesting temperature / current / status), heartbeats are sent in either direction at 100 ms intervals during the handshake period. The handshake success criterion is: receiving ≥3 consecutive valid VCU frames. ACK With MCU STS The time window must be ≤300 ms, and automatic baud rate / bit timing verification must be performed (e.g., 500kbps, SJW=1). If more than 2 frames are lost or more than 3 CRC / bit stuffing errors occur within 300 ms, the handshake is deemed to have failed, and the system will return to standby mode and report a "communication error (COMM)". ERR )".

[0065] In an optional implementation, the protection mode is determined based on a combination of system protection bits issued by the VCU and key measurements: the protection mode is entered when any one of the following conditions is true: high-voltage system not ready or emergency stop triggered (HV). RDY =0 or ESTOP=1); Insulation monitoring alarm (IMD) FLT =1); Main circuit breaker / contaminant abnormality (MAIN_CNT_ERR=1); DC bus undervoltage / overvoltage (e.g., U...). dc <400 V or >900 V, depending on the vehicle model); serious battery BMS malfunction (BMS) SEV =1); Drive chain overcurrent / overtemperature lockout (PWR) LOCK=1); After entering protection mode, the FCU remains in standby mode, disables driver enable, maintains low-frequency monitoring, and verifies the above conditions every 500 ms. It can only exit after clearing all conditions and maintaining stability for ≥2 s.

[0066] After the linkage is completed, the FCU immediately initiates a rapid self-test, which must be completed within 0.5 seconds. It should be noted that the purpose of the self-test is to confirm the health and reliability of the three links: first, it checks whether the input voltage falls within the set range (e.g., 10.5 V to 32 V) to prevent false triggering or device damage caused by overvoltage or undervoltage; then, it periodically sends heartbeat frames to the VCU and MCU to confirm the connectivity of the communication link. If there is no response within the set timeout period, it is determined to be a communication failure; next, it performs a continuity test on power drive devices such as IGBTs / MOSFETs using a micro-current to identify potential short circuits or open circuits; finally, it reads the initial value of the temperature sensor and verifies whether it is within a reasonable range (-40 ℃ to 150 ℃) and close to the ambient temperature (e.g., ambient ±5 ℃). When all the above items pass, the FCU reports "self-test passed" to the VCU and continues the process; if any item fails, the FCU will take either a downgraded operation (such as allowing operation under monitoring) or a lock-up (prohibiting the drive) strategy according to the fault level, and report the fault code until repair or condition is restored.

[0067] In an optional implementation, power supply detection: sampling the voltage at the FCU input terminal. ,like If the condition is met, pass; otherwise, record OV. UV Fault; Communication detection: Send FCU data at 100 ms intervals. HB And wait for VCU HB / MCU HB If no heartbeat is received from either end within 300 ms, then COMM is determined. ERR Drive conduction: Apply a micro-current test pulse to the power device during PWM=0 and drive off period, and measure the loopback voltage drop. If the calibration is successful within the calibration window, otherwise SHORT / OPEN; Temperature sensor: Read and ,like and Passed; otherwise, SENS RANGE / SENS DRIFT .

[0068] In an optional implementation, the fault levels are categorized as follows:

[0069] Grade A (Serious): COMM ERR SHORT, MAIN PWR UV / OV over-limit duration ≥100 ms;

[0070] Level B (Medium): SENS RANGE Duration ≥ 1 s;

[0071] Class C (Light): SENS DRIFT Brief frame drops;

[0072] Furthermore, degraded operation includes: for B / C level, taking the following actions: "only forward rotation, limit duty cycle to ≤60%, prohibit reverse rotation, shorten heartbeat cycle to 50 ms, and enable redundant temperature (if applicable)";

[0073] Lockout strategies include: immediately disabling Class A drivers (DRV). EN =0), red light on, standby mode.

[0074] For example, fault reporting is accomplished via a dedicated CAN DTC frame, with fields including {System ID, SPN / Fault Object, FMI / Fault Type, OC / Occurrence Count, TS / Timestamp}, and is reported repeatedly at 1 Hz until cleared.

[0075] It should be noted that, to ensure the air duct and blades are clean before the heat dissipation task begins, after the self-test passes, the technical solution provided in this embodiment unconditionally performs a power-on reverse dust removal. This is achieved by switching the motor phase sequence, causing the fan to generate airflow opposite to the normal heat dissipation direction. This directional airflow washes away and removes the dust deposited during shutdown from the air duct and blade surface. To avoid electrical and mechanical shocks caused by sudden loading, the reverse duty cycle is not given instantaneously, but increases by 10% every 200 ms from 0% until it reaches the set 40%, and is maintained for 15 seconds. During this period, the FCU monitors the motor current in real time. If the current exceeds 150% of the rated value and continues to reach the set criterion, the machine is immediately stopped and a "dust removal stall fault" is recorded to prevent overcurrent burnout caused by blockage or foreign objects. After the reverse operation ends, the machine stops for another 2 seconds to allow the dust to settle naturally after the airflow decays, reducing backflow. After this action is completed, the cleanliness of the air duct is initially restored, and the fan enters the temperature control speed regulation stage.

[0076] For example, the criteria for setting up dust collector stall failure include:

[0077] When phase current When the following formula is satisfied:

[0078]

[0079] If stalled, the machine should be stopped immediately.

[0080] in, , For speed, The minimum effective speed threshold (e.g., 50 rpm, used to distinguish between instantaneous load and actual stop). Rated phase current, This is an indicator function.

[0081] After entering the temperature control phase, the FCU periodically receives the motor temperature reported by the MCU via CAN. With controller temperature When both are below the first threshold (60 ℃), the fan remains stationary and enters low-power monitoring: the temperature update cycle is relaxed to no more than 5 s, and the CAN message frequency is reduced, thereby reducing power consumption and bus occupancy. It should be noted that this stage is set because forced ventilation under low-temperature conditions is unnecessary and will also lead to power consumption and noise. As long as the temperature remains below the low threshold, the system maintains this low-occupancy state. Once the temperature rises and crosses the threshold, the system automatically switches to medium-temperature linear speed regulation.

[0082] when or For any entry into the (60 ℃, 80 ℃) range, the method of this invention uses linear mapping to calculate the target duty cycle. To achieve on-demand matching of air volume to heat load, the objective function is defined as:

[0083]

[0084] Where T is temperature. For the target duty cycle, For motor temperature, For controller temperature, The duty cycle at the starting point of the linear mapping. =40%, The duty cycle at the endpoint of the linear mapping. =80%, , At 0, the fan does not start, and the system enters low-power monitoring mode. At that time, full load heat dissipation;

[0085] To prevent frequent adjustments due to minor temperature fluctuations, adjustments should only be made when the temperature change reaches a set range (e.g., ...). The target value is updated only once every time. In addition, the actual duty cycle smoothly transitions from the previous moment to the target value and is constrained by the maximum rate of change (e.g., not exceeding 5% / s) to suppress sudden changes in motor current and aerodynamic noise. Through this stage, the fan output and heat demand maintain a continuous and predictable correspondence, avoiding both underheating and reducing energy waste caused by overheating.

[0086] In an optional implementation, the rate of change constraint is used to limit the abrupt changes in motor current slope and aerodynamic noise, taking... That is, 5% / s, in the discrete control cycle Below, actual duty cycle From the goal Updated based on limit points:

[0087]

[0088] in, ,like A sudden increase (e.g., 60% → 80%), in The maximum increment per step at 50ms is Multi-step smooth approximation ensures controllable current ramp-up.

[0089] When the temperature continues to rise and reaches the second threshold (80 ℃), the system enters the high-temperature priority phase, which prioritizes thermal safety: the fan duty cycle immediately switches to 100%, no longer needing to follow the rate of change constraint, and provides maximum airflow at the fastest speed; when the temperature is still higher than the safe drop-off threshold (e.g. 75 ℃) after continuous full-load operation for a preset time (e.g. 10 min), the FCU reports a high-temperature alarm to the VCU, prompting the driver to take load reduction measures; if the temperature continues to climb to the over-temperature limit (e.g. 95 ℃), the FCU, while maintaining full-load ventilation, initiates a power limiting request to the MCU, reducing the heat source input through power-side derating until the temperature drops back to the safe range.

[0090] When the judgment (Second threshold, default 80 °C) Entering high temperature priority mode, the FCU immediately sets the PWM duty cycle to 100% and temporarily bypasses the rate of change limit (effective within one PWM cycle, such as ≤10 ms), while prohibiting the interference of inversion and derating commands on the fan.

[0091] To avoid temperature fluctuations, a hysteresis safety range is set: Exiting the high-temperature priority mode requires meeting certain conditions. And continue ,like Clearing high temperature alarms requires meeting certain conditions. (e.g., 75 °C) and continue ;

[0092] in, For temperature hysteresis, To retain the exit time, , The alarm clearing threshold and hold time settings ensure stable exit under thermal dynamics without frequent jitter.

[0093] Furthermore, to address the gradual accumulation of dust during prolonged forward ventilation, the present invention also provides a periodic reverse dust removal strategy triggered by working hours, wherein:

[0094] The FCU uses a built-in real-time clock to accumulate forward rotation working time. When the accumulated time reaches a set threshold (e.g., 4 hours, which can be calibrated within the range of 1 to 8 hours according to the working conditions of mining areas or urban distribution) and the system is not currently in a high-temperature full-load stage, the system will execute an online reverse cleaning sequence at an opportune time.

[0095] To minimize the impact on current operations and devices, the sequence includes four stages: smooth deceleration, stop buffering, reverse cleaning, and recovery by mapping. First, the current duty cycle is linearly reduced to 0% at a maximum rate of 5% / s, then stopped for 10 seconds. Next, a 40% duty cycle and a 15-second reverse are performed using the same parameters as the power-on reverse dust removal. After this, the cycle stops for another 10 seconds. Finally, based on the current temperature, the duty cycle is restored to the position corresponding to the point before dust removal through the above linear mapping (instead of starting from zero again). The working hours count for this cycle is then reset to zero, thus entering the next round of regular temperature control. This "re-cleaning" by working hours keeps the air duct in a relatively clean and low-resistance state for a long time, making the air volume and heat exchange capacity more stable.

[0096] The system switching between all the above stages follows a unified security constraint:

[0097] (1) Before any forward or reverse rotation, a short pause is first performed to release rotational inertia and eliminate electrical and mechanical transients caused by phase sequence switching;

[0098] (2) Except for the high temperature priority stage, all duty cycle changes are subject to the maximum rate of change limit in order to control current rise and aerodynamic noise;

[0099] Following the above implementation process, the system operates in a cyclical manner, following the sequence of "power-on linkage—health self-check—power-on cleaning—on-demand ventilation—high-temperature protection—cleaning again according to working hours." Without interrupting operations, dust accumulated in the air ducts is removed in a timely, low-impact, and predictable online manner, and the air volume and heat exchange efficiency remain stable over a long period. At the same time, the temperature control strategy has good tracking performance and boundary safety for heat load, significantly reducing energy consumption, noise, and device stress, and reducing manual maintenance and downtime, thus meeting the reliable heat dissipation and low-maintenance requirements of new energy trucks in harsh environments such as mining areas.

[0100] 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 dust control method for a cooling fan in a new energy truck, characterized in that, include: S1. When the key switch is in the ON position or the vehicle controller VCU sends a high-voltage power-on completion signal, the fan controller FCU is woken up by the low-voltage power supply and establishes CAN communication with the VCU and MCU to receive the vehicle enable command; if the vehicle is in fault protection mode, it will remain in standby until the fault is cleared. S2. Within the preset time limit, the power supply voltage range detection, communication link heartbeat detection, drive power device continuity detection and temperature sensor range detection are completed sequentially. If the self-test is passed, a self-test pass signal is sent to the VCU and the next step is entered. If the self-test fails, the system will be downgraded or locked according to the fault level and a fault code will be reported. The S2 includes: the acceptable range for power supply voltage detection is 10.5V to 32V; communication link heartbeat timeout is judged as a communication failure; the continuity detection of drive power devices is confirmed by injecting microcurrent to confirm open / short circuit; the temperature sensor range is -40℃ to 150℃ and the initial power-on value should be within ±5℃ of the ambient temperature; when the sensor drifts, it is judged as a minor fault, and degraded operation is allowed; when the drive circuit is short-circuited, it is judged as a serious fault, the fan is locked and the fault indicator is lit. S3. After the self-test passes, regardless of the current temperature, a reverse dust removal is forcibly performed. The reverse dust removal is achieved by switching the motor phase sequence. The duty cycle is increased from 0% to the preset duty cycle in a step-by-step manner and the motor runs for a preset time. During this period, the motor current is monitored and stall protection is implemented. After the end of the process, the motor is stopped to allow the dust to settle. S4. Collect motor temperature and controller temperature via CAN. When the motor temperature is less than or equal to the first threshold and the controller temperature is less than or equal to the first threshold, the fan does not start and enters low power monitoring. Update the temperature according to the set cycle and reduce the communication frequency. S5. When the motor temperature or the controller temperature falls into the range of the first threshold and the second threshold, the target duty cycle is obtained according to the temperature-duty cycle linear mapping, and the target is updated when the temperature change reaches the set magnitude. The S5 adopts the following linear mapping: the first threshold is 60℃, the second threshold is 80℃, and the duty cycle is calculated by the following formula: Where T is temperature. For the target duty cycle, For motor temperature, For controller temperature, The duty cycle at the starting point of the linear mapping. =40%, The duty cycle at the endpoint of the linear mapping. =80%, , At 0, the fan does not start, and the system enters low-power monitoring mode. At that time, full load heat dissipation; An update is triggered when the temperature change is ≥2℃ and the duty cycle change rate is less than 5% / second; S6. When the motor temperature is ≥ the second threshold or the controller temperature is ≥ the second threshold, the fan duty cycle is immediately switched to full load and kept at the highest priority until the temperature drops back to the safe range. When the full load operation reaches the set time and the temperature does not drop back to the safe threshold, a high temperature alarm is reported. When the temperature reaches the over-temperature limit, a power limiting request is initiated to the MCU. S7. The forward rotation working time is accumulated by the built-in clock of FCU. When the accumulated time reaches the period threshold, it is marked that dust removal needs to be performed. Under the condition that it is not in S6, the speed is smoothly reduced to 0, stopped, reversed according to the preset duty cycle, stopped, and the sequence of the corresponding duty cycle before dust removal is restored according to the temperature-duty cycle mapping to perform periodic reverse dust removal. In this system, any forward / reverse switching is preceded by a stop interval, and any change in duty cycle is limited by the maximum slope to reduce electrical and mechanical shocks.

2. The dust removal control method for a cooling fan in a new energy truck according to claim 1, characterized in that, The reverse dust removal is performed according to the following parameters: The reverse rotation direction is opposite to the forward rotation direction of heat dissipation. The duty cycle is set to 40%, and the duration is set to 15 seconds. The duty cycle increases from 0% to 40% in a stepped manner, with a step time of not less than 200ms; If the motor current exceeds 150% of the rated value during the reversal process, the machine should be stopped immediately and the dust removal stall fault should be recorded. After the reversal is completed, the rotation should stop for no less than 2 seconds.

3. The dust removal control method for a cooling fan in a new energy truck according to claim 1, characterized in that, The low-power monitoring cycle is no more than 5 seconds per time, and the CAN message frequency is reduced to reduce bus occupancy and power consumption.

4. The dust removal control method for a cooling fan in a new energy truck according to claim 1, characterized in that, The threshold for the duration of full-load operation in S6 is 10 minutes. When the full-load operation exceeds 10 minutes and the temperature is still not lower than 75°C, a high temperature alarm is reported. When the temperature reaches the over-temperature limit of 95°C, the motor output power is limited by requesting the MCU while maintaining full-load operation.

5. The dust control method for a cooling fan of a new energy truck according to claim 1 or 4, characterized in that, The default cycle threshold of S7 is 4 hours of cumulative forward rotation, and it can be calibrated by the host computer within the range of 1 to 8 hours. The execution sequence of S7 includes: reducing the current duty cycle to 0% at a change rate not exceeding 5% / second, stopping for 10 seconds, reversing at 40% duty cycle for 15 seconds, stopping again for 10 seconds, and restoring to the corresponding duty cycle before dust removal based on the temperature-duty cycle mapping before dust removal.

6. The dust removal control method for a cooling fan in a new energy truck according to claim 5, characterized in that, Before any forward / reverse switch or before switching from one stage to another, a stop interval shall be executed first, which shall be no less than 10 seconds; the duty cycle change shall be limited to a maximum change rate of 5% / second.

7. The dust removal control method for a cooling fan in a new energy truck according to claim 1, characterized in that, The FCU and VCU / MCU communicate via a CAN bus. The communication includes at least the following: high voltage power-on completion, self-test pass / fail, fan operation permission, high temperature alarm, over-temperature power limit request, and fault code reporting.

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