New energy loader thermal management control method and system

Abstract

A heat management control method for a new energy loader comprises the following steps that the refrigeration states of a battery and a cab are obtained, and the initial rotating speed value of a fan is determined according to a preset mapping relation; the initial pressure P1 (n) and the exhaust temperature of the compressor are obtained, and the corrected pressure P2 (n) is obtained after average filtering is conducted on the initial pressure P1 (n); performing weighted average operation on the P2 (n) and the previous filtering output value P3 (n-1) according to a preset first-order low-pass filtering algorithm to obtain a new filtering output value P3 (n); and the pressure value distribution state of the P3 (n) in the inspection period T is obtained, if the P3 (n) is always larger than the speed increasing threshold value in the inspection period T, the rotating speed of the fan is increased in the next inspection period T, and if the P3 (n) is always smaller than the speed reducing threshold value in the inspection period T, the rotating speed of the fan is reduced in the next inspection period T. According to the method, a cooling fan rotating speed control algorithm is optimized, the high pressure of the compressor can be kept in a normal working interval, frequent speed regulation of the fan can be reduced, and the service life of the fan is prolonged.

Description

Technical Field

[0001] This invention relates to the field of thermal management control technology, specifically to a thermal management control method and system for a new energy loader. Background Technology

[0002] Currently, the thermal management system of new energy loaders generally includes cab heating and cooling, battery heating and cooling, and power transmission system heat dissipation, and is divided into split type and integrated type.

[0003] The split-type thermal management system involves a variety of components, each of which operates independently and is controlled independently by multiple main controllers.

[0004] The integrated thermal management system unifies the cooling and heat dissipation of the cab, battery, and power transmission system with a high-power compressor and a large cooling fan. All systems share the same main controller for control, which is the future development trend.

[0005] Current split-type thermal management control systems for new energy loaders are typically supplied by multiple vendors, which is detrimental to the OEM's supply chain management. Furthermore, each independent system contains electronic components such as compressors, fans, and expansion valves, resulting in high component redundancy, a relatively high failure rate, and high prices. In terms of the control system, the lack of communication between systems prevents precise energy distribution across the vehicle, leading to high overall energy consumption.

[0006] The integrated thermal management system for new energy loaders, which represents the main development path for the next stage, relies on a unified thermal management main controller for heat dissipation management. However, it suffers from the following main problems: (1) To protect the compressor's high pressure within its normal operating range, the integrated thermal management system needs to adjust the cooling fan speed in a timely manner. Typically, different fan speeds correspond to different ranges of compressor high pressure. This method has two drawbacks: ① Too many pressure range segments will cause the fan to frequently adjust its speed. With the fan frequently accelerating and decelerating, the fan bearings will wear excessively, shortening the fan's lifespan.

[0007] ② If there are too few pressure range segments, the fan speed will vary too much when adjusting the speed across pressure ranges. The fan speed will sound like it is fluctuating, and it will be in a state of rapid acceleration and deceleration. This will also affect the bearing life and increase the load on the fan power control port. In addition, it will increase the pressure fluctuation range, and may even lead to insufficient heat dissipation in the previous speed range, resulting in excessive pressure, and excessive heat dissipation in the next speed range, wasting energy.

[0008] (2) The refrigerant distribution is not intelligent enough, resulting in a waste of energy and compressor cooling performance. When the cab and battery are cooled at the same time, the thermal management main controller limits the maximum cooling capacity required by the cab cooling system and the maximum cooling capacity of the battery system according to the preset maximum cooling capacity. However, under extreme conditions, the battery cooling is insufficient, but the cab cooling is sufficient, or the cab cooling is insufficient, but the battery cooling is sufficient, but the battery cooling is sufficient. No intelligent adjustment is performed.

[0009] (3) The control algorithm is highly dependent on the supplier. The vehicle controller cannot intervene in the refrigerant distribution ratio and cooling fan speed control, and cannot realize the independent development of thermal management control strategy. When carrying out rapid technology iteration and matching in the later stage, it is limited by the supplier's software development capabilities and target execution speed. Summary of the Invention

[0010] To address the technical problems existing in the background art, the present invention provides a thermal management control method and system for new energy loaders.

[0011] The technical solution of this invention is as follows: A thermal management control method for a new energy loader is disclosed. This method is applicable to integrated thermal management systems for battery thermal management, cab air conditioning, and vehicle powertrain. Specifically, it includes the following steps: S1. Obtain the battery and cab cooling status, and determine the initial fan speed value according to the preset mapping relationship; S2. Obtain the initial pressure P1(n) and exhaust temperature of the compressor, and obtain the corrected pressure P2(n) after mean filtering of the initial pressure P1(n); S3. Perform a weighted average operation on P2(n) and the previous filtered output value P3(n-1) according to the preset first-order low-pass filtering algorithm to obtain a new filtered output value P3(n); S4. Obtain the pressure value distribution of P3(n) within the inspection cycle T; If P3(n) is always greater than the acceleration threshold within the inspection cycle T, then proceed to step S41. If P3(n) is always less than the deceleration threshold within the inspection cycle T, then proceed to step S42. S41. Increase the fan speed during the next inspection cycle T; S42. Reduce the fan speed during the next inspection cycle T.

[0012] As one implementation method, the initial fan speed is divided into three levels, corresponding to battery cooling single cooling state 1, cab cooling single cooling state 2, and battery and cab cooling dual cooling state 3.

[0013] In step S2, the highest priority is set. If the exhaust temperature is greater than the protection threshold, the compressor is controlled to reduce its frequency or stop.

[0014] In step S3, the first-order low-pass filtering algorithm uses the following formula: P3(n) = α* P2(n) + (1 - α) * P3(n-1), Where α is the filter coefficient, 0 < α < 1.

[0015] Preferably, α is not greater than 0.1.

[0016] In one implementation method, the compressor's pressure range is [0-Z], divided into four intervals: Interval 1 is [0-W]; Interval 2 is [WX]; Interval 3 is [XY]; Interval 4 is [YZ]; Where X is the acceleration threshold and W is the deceleration threshold.

[0017] In one implementation, in step S41, it is determined whether P3(n) is always greater than Y. If so, the fan speed is increased to the maximum value in the next inspection cycle T. If not, the fan speed is increased by S1 in the next inspection cycle T.

[0018] Step S42 is to reduce the fan speed by S2 in the next inspection cycle T.

[0019] By adjusting the fan speed by a fixed value only within one inspection cycle T, frequent speed adjustments can be avoided, thus extending the fan's lifespan.

[0020] To address the issue of insufficient intelligence in refrigerant distribution, this invention further includes step S5, which specifically comprises: S5. Obtain the battery temperature. When the battery temperature is higher than the normal operating temperature for a longer period than the preset time, adjust the refrigerant distribution ratio valve to close the refrigerant passage to the cab.

[0021] The system acquires the cab temperature. If the cab temperature remains above the target temperature for a longer period than a preset time, it checks whether the battery temperature is above the normal operating temperature. If not, it adjusts the refrigerant distribution valve to increase the refrigerant flow to the cab.

[0022] The present invention also provides a thermal management control system for a new energy loader, including a processor and a memory. The memory stores computer program instructions, and when the computer program instructions are executed by the processor, the above-mentioned thermal management control method for the new energy loader is implemented.

[0023] Through the above design, the thermal management control method and system for a new energy loader of the present invention has the following beneficial effects: 1. This method is applied to the integrated thermal management system for battery thermal management, cab air conditioning system, and vehicle powertrain system. It directly participates in the control of refrigerant distribution ratio and cooling fan speed through the vehicle controller. Compared with the traditional multiple independent systems, it reduces the duplication of parts, reduces the failure rate, and reduces product costs.

[0024] 2. The cooling fan speed control algorithm has been optimized, which can ensure that the compressor high pressure is kept within the normal operating range, and reduce the frequency of fan speed adjustment, thus extending the fan life.

[0025] 3. The refrigerant distribution ratio valve control strategy has been optimized to intelligently adjust the refrigerant distribution ratio under extreme operating conditions, maximize the utilization of compressor performance, and optimize energy efficiency. Attached Figure Description

[0026] In the attached diagram: Figure 1 This is a schematic diagram of an integrated thermal management system. Figure 2 This is a flowchart of the control method of the present invention; Detailed Implementation See Figure 1 and Figure 2 This embodiment provides a thermal management control method for a new energy loader. This control method is applicable to integrated thermal management systems for battery thermal management, cab air conditioning, and vehicle powertrain. See [link to relevant documentation]. Figure 1 As shown.

[0027] This embodiment calibrates the normal operating high pressure range of the compressor [0-WXYZ] bar, divided into 4 intervals: Interval 1 is [0-W], which indicates that the compressor pressure is low and there is no risk. Interval 2 is [WX], representing the optimal operating pressure range of the compressor; Interval 3 is [XY], which indicates that the pressure is relatively high, but within a safe range; Interval 4 is [YZ], indicating excessive pressure; Where X is the acceleration threshold and W is the deceleration threshold.

[0028] The VCU (Vehicle Control Unit) acts as the main controller, and the controlled actuator is the cooling fan.

[0029] The present invention specifically includes the following steps: S1. Obtain the battery and cab cooling status, and determine the initial fan speed value according to the preset mapping relationship.

[0030] The fan's initial speed is divided into three levels, corresponding to battery-only cooling state 1, cab-only cooling state 2, and battery and cab-only cooling state 3.

[0031] In single-cooling mode, when the compressor is running at maximum power, the required fan speed to maintain the pressure in range 2 is Speed1. In the calibrated cab single-cooling mode, when the compressor is running at maximum power, the required fan speed to maintain the pressure in range 2 is Speed2. In the calibrated dual-cooling mode, when the compressor is running at maximum power, the required fan speed to maintain the pressure in range 2 is Speed3.

[0032] The core idea of ​​this control method is to first determine whether the thermal management system is in single-cooling state 1, single-cooling state 2, or dual-cooling state 3, and then assign different initial fan speed values. When adjusting the fan speed, a special control method is used to avoid rapid and frequent fan speed adjustments, avoiding sudden acceleration and deceleration by slightly increasing or decreasing the fan speed.

[0033] When the thermal management controller is turned on, the VCU determines whether the current cooling state is single cooling state 1, single cooling state 2, or dual cooling state 3, and then sends the corresponding speed command Speed1, Speed2, or Speed3.

[0034] S2 and VCU acquire the compressor initial pressure P1(n) and exhaust temperature reported by the thermal management controller in real time, and obtain the corrected pressure P2(n) after mean filtering of the initial pressure P1(n).

[0035] In this step, the highest priority is set. If the exhaust temperature exceeds the protection threshold, the compressor will be controlled to reduce its frequency or shut down.

[0036] S3. Perform a weighted average operation on P2(n) and the previous filtered output value P3(n-1) according to the preset first-order low-pass filtering algorithm to obtain a new filtered output value P3(n).

[0037] First-order low-pass filtering algorithms are mainly suitable for slowly changing signals, allowing low-frequency signals to pass through while suppressing high-frequency noise.

[0038] The main sources of high-frequency signals in this system are: 1. Sensor electrical noise and electromagnetic interference 2. Pressure pulsations caused by the periodic intake and exhaust of the compressor. In this embodiment, the first-order low-pass filtering algorithm uses the following formula: P3(n) = α* P2(n) + (1 - α) * P3(n-1), Here, α is the filter coefficient, 0 < α < 1, which determines the magnitude of the filter's "inertia".

[0039] The smaller the α value, the stronger the filtering effect and the smoother the output waveform, but the slower the response speed to changes in input pressure.

[0040] The larger the α value, the weaker the filtering effect, the more original the output waveform, and the faster the response speed to changes in input pressure. For signals such as compressor pressure that do not change drastically, this embodiment selects a small α (such as 0.05 or 0.1) to achieve a good balance between smoothness and response speed.

[0041] S4. Obtain the pressure value distribution of P3(n) within the inspection cycle T; If P3(n) is always greater than the acceleration threshold within the inspection cycle T, then proceed to step S41. If P3(n) is always less than the deceleration threshold within the inspection cycle T, then proceed to step S42. If P3(n) remains within the optimal operating pressure range 2 within the inspection cycle T, no operation is required; simply continue the inspection.

[0042] S41. Increase the fan speed during the next inspection cycle T; It is worth noting that the increase in fan speed in this invention is not achieved by setting multiple speed ranges and automatically adjusting the speed as in the prior art.

[0043] As one of the inventive points of this invention, in step S41, it is determined whether P3(n) is always greater than Y. If so, it indicates that the pressure is too high and the fan speed is seriously too low at this time. It is necessary to directly increase the fan speed to the maximum value to achieve rapid heat dissipation and avoid failure. Then, in the next inspection cycle T, the fan speed will be increased to the maximum value. If not, increase the fan speed by S1 in the next inspection cycle T. In this way, the fan speed remains constant within each inspection cycle, avoiding frequent speed adjustments. After the fan speed adjustment in the current inspection cycle, if P3(n) is still within interval 3 in the next cycle, continue increasing the fan speed by S1 until, after several cycles, P3(n) is less than the speed-up threshold and falls within interval 2, maintaining the current fan speed for heat dissipation.

[0044] S42. Reduce the fan speed during the next inspection cycle T.

[0045] Similarly, the reduction of fan speed in this invention is not achieved by setting multiple speed ranges and automatically adjusting the speed as in the prior art.

[0046] Instead, in the next inspection cycle T, the fan speed is reduced by S2, similar to step S41. After several cycles, P3(n) is in interval 2, maintaining the current fan speed for heat dissipation.

[0047] By adjusting the fan speed by a fixed value only within one inspection cycle T, frequent speed adjustments can be avoided, thus extending the fan's lifespan.

[0048] To address the issue of insufficient intelligence in refrigerant distribution, this invention further includes step S5, which specifically comprises: S5. Obtain battery temperature. When the battery temperature is higher than the normal operating temperature for a longer than a preset time, adjust the refrigerant distribution ratio valve to close the refrigerant passage to the cab, so that the refrigerant flow to the battery reaches the maximum to prioritize battery protection.

[0049] The system acquires the cab temperature. If the cab temperature remains above the target temperature for a longer than preset time, it checks if the battery temperature is above the normal operating temperature (prioritizing battery cooling). If not, it adjusts the refrigerant distribution valve to increase the refrigerant flow to the cab. This achieves intelligent distribution of cooling power under the same compressor cooling capacity.

[0050] The present invention also provides a thermal management control system for a new energy loader, including a processor and a memory. The memory stores computer program instructions, and when the computer program instructions are executed by the processor, the above-mentioned thermal management control method for the new energy loader is implemented.

Claims

1. A thermal management control method for a new energy loader, characterized in that, Includes the following steps: S1. Obtain the battery and cab cooling status, and determine the initial fan speed value according to the preset mapping relationship; S2. Obtain the initial pressure P1(n) and exhaust temperature of the compressor, and obtain the corrected pressure P2(n) after mean filtering of the initial pressure P1(n); S3. Perform a weighted average operation on P2(n) and the previous filtered output value P3(n-1) according to the preset first-order low-pass filtering algorithm to obtain a new filtered output value P3(n); S4. Obtain the pressure value distribution of P3(n) within the inspection cycle T; If P3(n) is always greater than the acceleration threshold within the inspection cycle T, then proceed to step S41. If P3(n) is always less than the deceleration threshold within the inspection cycle T, then proceed to step S42. S41. Increase the fan speed during the next inspection cycle T; S42. Reduce the fan speed during the next inspection cycle T.

2. The method according to claim 1, characterized in that, The initial fan speed is divided into three levels, corresponding to battery-only cooling state 1, cab-only cooling state 2, and battery and cab-only cooling state 3.

3. The method according to claim 1, characterized in that, In step S2, the highest priority is set. If the exhaust temperature is greater than the protection threshold, the compressor is controlled to reduce its frequency or stop.

4. The method according to claim 1, characterized in that, In step S3, the first-order low-pass filtering algorithm uses the following formula: P3(n) = α* P2(n) + (1 - α) * P3(n-1), Where α is the filter coefficient, 0 < α < 1.

5. The method according to claim 1, characterized in that, α is no greater than 0.

1.

6. The method according to any one of claims 1-5, characterized in that, The compressor has a pressure range of [0-Z], divided into 4 intervals: Interval 1 is [0-W]; Interval 2 is [WX]; Interval 3 is [XY]; Interval 4 is [YZ]; Where X is the acceleration threshold and W is the deceleration threshold.

7. The method according to claim 6, characterized in that, In step S41, it is determined whether P3(n) is always greater than Y. If so, the fan speed is increased to the maximum value in the next inspection cycle T. If not, the fan speed is increased by S1 in the next inspection cycle T.

8. The method according to claim 6, characterized in that, Step S42 is to reduce the fan speed by S2 in the next inspection cycle T.

9. The method according to claim 1, characterized in that, It also includes step S5, which is as follows: S5. Obtain the battery temperature. When the battery temperature is higher than the normal operating temperature for a longer period than the preset time, adjust the refrigerant distribution ratio valve to close the refrigerant passage to the cab. The system acquires the cab temperature. If the cab temperature remains above the target temperature for a longer period than a preset time, it checks whether the battery temperature is above the normal operating temperature. If not, it adjusts the refrigerant distribution valve to increase the refrigerant flow to the cab.

10. A thermal management control system for a new energy loader, characterized in that, It includes a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the thermal management control method for a new energy loader according to any one of claims 1-9 is implemented.

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