Cooling control system and method for high-voltage lithium battery-based entire electric forklift truck

Abstract

A cooling control system for a high-voltage lithium battery-based entire electric forklift truck, comprising a controller, a fan, a plurality of cooling water pumps, and temperature sensors that are respectively and correspondingly arranged at the positions of motors and motor controllers of motor and electric control systems of a forklift truck, wherein the fan blows air to dissipate heat of each motor and electric control system of the electric forklift truck; a set of motor and electric control system is independently provided with a cooling water pump, the cooling water pump drives a cooling liquid to circulate so as to dissipate heat of the corresponding motor and electric control system, and the cooling water pump and the fan are independently controlled. Provided is a control method for a high-voltage lithium battery-based entire electric forklift truck. According to the cooling control system, the electric energy consumption of a cooling system is reduced while the performance of a whole vehicle is satisfied; and differential cooling is carried on the motors and the controllers, so that the fan and the cooling water pump are controlled on the basis of requirements, thereby achieving the purpose of accurate heat dissipation, and ensuring the heat dissipation timeliness of the motors and the motor controllers.

Description

High-voltage lithium-ion electric forklift vehicle cooling control system and control method Technical Field

[0001] The present invention relates to the field of electric forklift control, and in particular to a high-voltage lithium-ion electric forklift vehicle cooling control system and control method. Background Art

[0002] With the increasingly severe environmental and energy problems, electric forklifts have begun to slowly replace internal combustion forklifts due to their superior characteristics, attracting more and more attention and attention from people, and have a huge market.

[0003] To meet the diverse needs of customers, high-voltage lithium-ion electric forklifts currently on the market require comprehensive functionality. Therefore, each vehicle features multiple motors and electronic controls. Furthermore, high-voltage lithium-ion electric forklifts require robust performance. As vehicle performance improves, so too does the need for a cooling system. The cooling system is required to cool the motors and electronic controls to ensure they operate efficiently. Traditional motor and control cooling methods in electric forklifts suffer from significant flow resistance and the inability to precisely control the temperature of individual motors and controls. This can lead to overheating of a single motor or control during vehicle operation, necessitating the cooling system's activation. At this point, the temperatures of the other motors and controls are far below the set temperature for safe operation. This not only wastes electricity but also reduces cooling efficiency, severely impacting vehicle operating time and overall performance.

[0004] Current vehicle cooling systems adjust the coolant flow rate and radiator ventilation to meet the cooling requirements of the motor and motor controller under varying operating conditions. In current motor and electronic control cooling systems, the controller controls the water pump and fan based on the motor and electronic control temperatures. This cooling control method is relatively simple, but the control algorithm still has significant room for optimization.

[0005] In summary, how to improve the reliability, efficiency and energy saving of the cooling system of high-voltage lithium-ion electric forklifts, as well as improve the performance of the entire vehicle, has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0006] In view of the above, the present invention aims to provide a high-voltage lithium-ion electric forklift vehicle cooling control system and control method to solve the above-mentioned technical problems.

[0007] The present invention provides a high-voltage lithium-ion electric forklift vehicle cooling control system, comprising: a controller, a fan, several cooling water pumps, and temperature sensors respectively arranged at each motor of the forklift and each motor and motor controller in the electronic control system;

[0008] The fan blows air and dissipates heat for the motors and electronic control system of the electric forklift;

[0009] Each set of motor and electronic control system is independently equipped with a cooling water pump, which drives the coolant circulation to dissipate heat for the corresponding motor and electronic control system;

[0010] The cooling water pump and fan are controlled independently.

[0011] In at least one possible implementation manner, the forklift vehicle controller is used as the controller configured with a PID module, and the output electrical signal of the forklift vehicle controller is a pulse width modulation signal.

[0012] In at least one possible implementation, the motor and electronic control system includes: a traction motor and a traction controller, a hydraulic pump motor and a hydraulic pump controller.

[0013] In at least one possible implementation, the cooling control system further includes: an oil circuit heat sink integrated in the forklift vehicle radiator, and the oil circuit heat sink is located below the fan, and the hydraulic oil in the forklift hydraulic system flows through the oil circuit heat sink and cooperates with the fan for circulation cooling and heat dissipation.

[0014] In at least one possible implementation manner, the oil circuit heat sink is a multi-row grid structure.

[0015] In at least one possible implementation manner, the oil circuit heat sink is connected to the original hydraulic oil circuit via a solenoid valve bypass.

[0016] The present invention also provides a high-voltage lithium-ion electric forklift vehicle cooling control method, comprising:

[0017] After the electric forklift is powered on, determine whether the motor and electronic control system are in working condition;

[0018] After determining that the motor and the electronic control system are in the working state, respectively obtaining the actual temperature of each motor and the motor controller in the electronic control system in real time;

[0019] Differentiated cooling control is performed using the actual temperature and the pre-set fan on threshold and fan off threshold, as well as the water pump on threshold and water pump off threshold of each cooling water pump independently configured corresponding to each motor and electronic control system, wherein the fan on threshold, the fan off threshold, the water pump on threshold and the water pump off threshold all adopt at least two levels of setting values ​​in multiple gears.

[0020] In at least one possible implementation, the differentiated cooling control includes a fan control strategy:

[0021] If the actual temperature of the motor and the motor or its controller in the electronic control system exceeds the preset fan start threshold of different levels, PID control is performed according to the difference between the actual temperature and the corresponding fan start threshold to control the fan to enter the preset and corresponding different speed states;

[0022] If the actual temperature of the motor and the motor or its controller in the electronic control system is lower than the respective preset fan shutdown thresholds of different levels, the fan is directly controlled to enter the preset and corresponding different speed states or stop running state.

[0023] In at least one possible implementation, the differentiated cooling control includes a cooling water pump control strategy:

[0024] If the actual temperature of the motor or its controller in the motor and electronic control system exceeds the preset water pump start threshold of different levels, PID control is performed according to the difference between the actual temperature and the corresponding water pump start threshold, and the independent cooling water pump corresponding to each motor and electronic control system is controlled to enter the preset different speed states;

[0025] If the actual temperature of the motor or its controller in the motor and electronic control system is lower than the respective preset water pump shutdown threshold of different levels, the independent cooling water pump corresponding to each motor and electronic control system will be directly controlled to enter the preset different speed state or stop running state.

[0026] In at least one possible implementation, the cooling control method further includes: when it is detected that the fan is started, triggering the solenoid valve preset at the oil circuit heat sink and the original hydraulic oil circuit to switch the hydraulic oil flow path from the original hydraulic oil circuit pipeline to the oil circuit heat sink integrated in the forklift vehicle radiator and located below the fan.

[0027] Compared with the existing technology, the main design concept of the present invention is that it includes a controller, a fan, several cooling water pumps, and temperature sensors respectively arranged at each motor and motor controller of the forklift's electric control system. The fan blows air to dissipate heat for each motor and electric control system of the electric forklift. A set of motors and electric control systems is independently equipped with a cooling water pump, and the cooling water pump drives the coolant circulation to dissipate heat for the corresponding motors and electric control systems. The control of the cooling water pump and the fan are independently controlled. While meeting the performance of the entire vehicle, the present invention reduces the power consumption of the cooling system. By performing differentiated cooling on each motor and controller, the fan and cooling water pump can be controlled on demand, achieving the purpose of precise heat dissipation and ensuring timely heat dissipation of the motors and motor controllers.

[0028] In addition, the vehicle radiator is also integrated with an oil circuit heat sink (oil fan), so that the hydraulic oil of the vehicle's hydraulic system is circulated and cooled through the oil fan to dissipate heat, which can further improve the working performance of the vehicle and make the vehicle work efficiently and safely. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0030] FIG1 is a schematic diagram of a cooling control system for a high-voltage lithium-ion electric forklift provided by an embodiment of the present invention;

[0031] FIG2 is a flow chart of a cooling control method for a high-voltage lithium-ion electric forklift provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0033] The present invention proposes an embodiment of a vehicle cooling control system for a high-voltage lithium-ion electric forklift. Specifically, as shown in FIG1 , the cooling control system includes: a controller, a fan, several cooling water pumps, and temperature sensors respectively provided at each motor and motor controller in the forklift's electronic control system;

[0034] The fan blows air to dissipate heat for each motor and electronic control system of the electric forklift, and a set of motors and electronic control systems is independently equipped with a cooling water pump. The motors and electronic control systems described here may include traction motors and their controllers, hydraulic pump motors and their controllers, etc. The aforementioned cooling water pump drives the coolant circulation to dissipate heat for the corresponding motors and electronic control systems. In addition, the control of the cooling water pump and the control of the fan are independently controlled. It can be understood that the forklift vehicle controller can be used as a controller equipped with a PID module, which outputs a pulse width modulation signal. Therefore, different duty cycles can be output according to the specific selected control strategy, thereby controlling the fan and several cooling water pumps to run at different speeds.

[0035] The following will schematically illustrate the cooling control method for a high-voltage lithium-ion electric forklift vehicle using an optional PID control mode, as shown in Figure 2:

[0036] Step S1: After the electric forklift is powered on, determine whether the motor and the electronic control system are in working state;

[0037] Step S2: After determining that the motor and the electronic control system are in the working state, respectively obtain the actual temperature of each motor and the motor controller in the electronic control system in real time;

[0038] Step S3: Perform differentiated cooling control using the actual temperature and the preset fan on threshold and fan off threshold, as well as the water pump on threshold and water pump off threshold of each cooling water pump independently configured for each motor and electronic control system.

[0039] In particular, to enhance the effect of differentiated fine cooling control, in some preferred embodiments, the fan on threshold, the fan off threshold, the water pump on threshold, and the water pump off threshold all adopt at least two levels of multi-level setting values. Here, refer to the following for a detailed description:

[0040] (1) The fan control strategy in the cooling control system specifically includes:

[0041] If the actual temperature of the motor or motor controller (including the motor and electronic control system of the traction or hydraulic pump) (which can be obtained by different temperature sensors of the corresponding motor and corresponding controller) exceeds the respective preset fan first-level opening temperature threshold (in actual operation, each motor and each controller can be pre-configured with their own corresponding fan first-level opening temperature threshold, that is, the motor in a set of motors and electronic control systems has its first-level threshold, such as 55°C, and the motor controller also has its first-level threshold, such as 70°C, which will not be repeated below), the difference between the actual temperature of the motor or its controller and the fan first-level opening temperature threshold (hereinafter referred to as the difference between the two) is used as a parameter of the built-in PID module of the forklift vehicle controller for processing, and the corresponding pulse width modulation signal is output to control the fan to enter a relatively low-speed operation state.

[0042] If the actual temperature of the motor or motor controller exceeds the respective preset fan level 2 activation temperature threshold, the difference between the two is processed as a PID control parameter (PID control is a well-known control algorithm and is not described in detail in this invention), and a corresponding pulse-width modulation signal is output to control the fan to enter a relatively medium-speed operation state. If the actual temperature of the motor or motor controller exceeds the respective preset fan level 3 activation temperature threshold, the difference between the two is processed as a PID control parameter, and a corresponding pulse-width modulation signal is output to control the fan to enter a relatively high-speed operation state.

[0043] Conversely, when the actual temperature of the motor or motor controller is lower than the respective preset fan level 3 shutdown temperature threshold, the fan is controlled to enter a relatively medium-speed operation state. When the actual temperature of the motor or motor controller is lower than the respective preset fan level 2 shutdown temperature threshold, the fan is controlled to enter a low-speed operation state. When the actual temperature of the motor or motor controller is lower than the respective preset fan level 1 shutdown temperature threshold, the fan is controlled to stop.

[0044] In addition, based on the aforementioned fan control implementation method, it can also be considered that the cooling control system also includes: an oil circuit heat sink (preferably a multi-row grid structure) integrated at the radiator of the forklift vehicle, and the oil circuit heat sink is located below the fan. As a result, the hydraulic oil in the forklift hydraulic system can also flow through the oil circuit heat sink and cooperate with the fan to circulate and cool the heat, thereby further improving the working performance of the vehicle and making the vehicle work efficiently and safely. As for the control method, in addition to allowing the hydraulic oil to flow directly into the oil circuit heat sink, it is also possible to consider using an electronic control method in conjunction with the fan, specifically:

[0045] The oil radiator is connected to the original hydraulic oil circuit via a solenoid valve bypass. Under normal circumstances, the hydraulic oil flows through the original pipeline unless it is overheated. Once the fan is detected, the solenoid valve closes the original hydraulic oil pipeline and connects the oil radiator, switching the hydraulic oil flow path and allowing the hydraulic oil to flow into the oil radiator. The activated fan allows the oil radiator to efficiently remove the hydraulic oil heat from its interior, achieving an auxiliary cooling effect.

[0046] (2) The cooling water pump control strategy in the cooling control system specifically includes:

[0047] As mentioned above, the motors and electronic controls of high-voltage lithium-ion electric forklifts can be divided into two functional categories: the traction motor and traction motor controller responsible for driving, and the hydraulic pump motor and pump motor controller responsible for loading and unloading. To ensure precise and energy-efficient cooling and heat dissipation of each motor and electronic control system, a cooling water pump is equipped for each of these two functional categories. This achieves efficient and precise cooling, while also being more energy-efficient for the entire vehicle.

[0048] Specifically, if the actual temperature of the traction motor or the traction motor controller exceeds the respective preset water pump first-level start-up temperature threshold, the difference between the two is processed as a PID control parameter, and the corresponding pulse width modulation signal is output to control the first cooling water pump of the corresponding traction motor electronic control to enter a relatively low-speed operation state, driving the coolant flow to cool the traction motor and the traction motor controller.

[0049] If the actual temperature of the traction motor or the traction motor controller exceeds the respective preset water pump secondary opening temperature threshold, the difference between the two will be processed as a PID control parameter, and the corresponding pulse width modulation signal will be output to control the first cooling water pump to enter a relatively high-speed operation state, driving the coolant to flow rapidly to quickly cool down the traction motor and the traction motor controller, so that the traction motor and the traction motor controller can work efficiently and safely.

[0050] Conversely, if the actual temperature of the traction motor or the traction motor controller is lower than the respective preset water pump second-stage shutdown temperature threshold, the first cooling water pump is controlled to enter a relatively low-speed operation state. If the actual temperature of the traction motor or the traction motor controller is lower than the respective preset water pump first-stage shutdown temperature threshold, the first cooling water pump is controlled to stop operation.

[0051] If the actual temperature of the hydraulic pump motor or the pump motor controller exceeds the respective preset water pump first-level opening temperature threshold, the difference between the two will be processed as a PID control parameter, and the corresponding pulse width modulation signal will be output to control the second cooling water pump of the corresponding hydraulic pump motor electronic control to enter a relatively low-speed operation state, driving the coolant flow to cool the hydraulic pump motor and the pump motor controller.

[0052] If the actual temperature of the hydraulic pump motor or the pump motor controller exceeds the respective preset water pump secondary opening temperature threshold, the difference between the two will be processed as a PID control parameter, and the corresponding pulse width modulation signal will be output to control the second cooling water pump to enter a relatively high-speed operation state, driving the coolant to flow rapidly to quickly cool down the hydraulic pump motor and the pump motor controller, so that the hydraulic pump motor and the pump motor controller can work efficiently and safely.

[0053] Conversely, if the actual temperature of the hydraulic pump motor or pump motor controller is lower than the respective preset water pump secondary shutdown temperature threshold, the second cooling water pump is controlled to enter a relatively low-speed operation state. If the actual temperature of the hydraulic pump motor or pump motor controller is lower than the respective preset water pump primary shutdown temperature threshold, the second cooling water pump is controlled to stop operation.

[0054] In summary, the present invention regulates and controls the operation and operating speed of the fan and cooling water pump of the cooling and heat dissipation system based on the traction motor temperature, the traction motor electronic control temperature, the hydraulic pump motor temperature, and the hydraulic pump motor electronic control temperature through the vehicle controller. Differentiated cooling is performed on each motor and electronic control, and the fan and cooling water pump are controlled on demand to accurately, quickly and effectively cool each object. Moreover, the operation of the fan and cooling water pump can be controlled in a timely, efficient and energy-saving manner to ensure the timely heat dissipation of the motor body and the motor controller, thereby improving the performance of the entire vehicle. As a result, the present invention avoids the phenomenon of overheating or overcooling of individual motors or motor controllers, and reduces the power consumption of the cooling system while ensuring safe operation and the performance of the entire vehicle. At the same time, differentiated and precise control can reduce the flow resistance of the system, further reduce the overall system power consumption, and extend the operating time of the high-voltage lithium-ion electric forklift.

[0055] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred modes can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the scope of implementation of the present invention is not limited to what is shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. A high-voltage lithium-ion electric forklift vehicle cooling control system, characterized in that: include: A controller, a fan, a plurality of cooling water pumps, and temperature sensors respectively arranged at each motor and motor controller in the forklift motor and the electronic control system; The fan blows air and dissipates heat for each motor and the electronic control system of the electric forklift; A set of motor and electronic control system is independently equipped with a cooling water pump, and the cooling water pump drives the coolant circulation to dissipate heat for the corresponding motor and electronic control system; The cooling water pump control and the fan control are independent.

2. The high-voltage lithium-ion electric forklift vehicle cooling control system according to claim 1 is characterized in that: The forklift vehicle controller is used as the controller equipped with a PID module, and the output electrical signal of the forklift vehicle controller is a pulse width modulation signal.

3. The high-voltage lithium-ion electric forklift vehicle cooling control system according to claim 1 is characterized in that: The motor and electric control system include: a traction motor and a traction controller, a hydraulic pump motor and a hydraulic pump controller.

4. The high-voltage lithium-ion electric forklift vehicle cooling control system according to any one of claims 1 to 3, characterized in that: The cooling control system also includes: an oil circuit heat sink integrated at the forklift vehicle radiator, and the oil circuit heat sink is located below the fan. The hydraulic oil in the forklift hydraulic system flows through the oil circuit heat sink and cooperates with the fan to circulate and cool the oil.

5. The high-voltage lithium-ion electric forklift vehicle cooling control system according to claim 4 is characterized in that: The oil circuit heat sink is a multi-row grid structure.

6. The high-voltage lithium-ion electric forklift vehicle cooling control system according to claim 4, characterized in that: The oil circuit heat sink is connected to the original hydraulic oil circuit via a solenoid valve bypass.

7. A high-voltage lithium-ion electric forklift vehicle cooling control method, characterized in that: include: After the electric forklift is powered on, determine whether the motor and electronic control system are in working condition; After determining that the motor and the electric control system are in working state, respectively obtaining the actual temperature of each motor and the motor controller in the electric control system in real time; Differentiated cooling control is performed by utilizing the actual temperature and the preset fan on threshold and fan off threshold of the fans for cooling all motors and electronic control systems, as well as the water pump on threshold and water pump off threshold of each cooling water pump independently configured for each motor and electronic control system, wherein the fan on threshold, the fan off threshold, the water pump on threshold and the water pump off threshold all adopt at least two levels of setting values ​​with multiple gears.

8. The high-voltage lithium-ion electric forklift vehicle cooling control method according to claim 7, characterized in that: The differentiated cooling control includes fan control strategies: If the actual temperature of the motor and the motor or its controller in the electric control system exceeds the preset fan opening threshold of different levels, PID control is performed according to the difference between the actual temperature and the corresponding fan opening threshold to control the fan to enter the preset and corresponding different speed states; If the actual temperature of the motor and the motor or its controller in the electric control system is lower than the respective preset fan shutdown thresholds of different levels, the fan is directly controlled to enter the preset and corresponding different speed states or stop running state.

9. The high-voltage lithium-ion electric forklift vehicle cooling control method according to claim 7, characterized in that: The differentiated cooling control includes a cooling water pump control strategy: If the actual temperature of the motor or its controller in the motor and the electronic control system exceeds the preset water pump start threshold of different levels, PID control is performed according to the difference between the actual temperature and the corresponding water pump start threshold, and the independent cooling water pump corresponding to each motor and electronic control system is controlled to enter the preset different speed states; If the actual temperature of the motor or its controller in the motor and electronic control system is lower than the preset water pump shutdown threshold of different levels, the independent cooling water pump corresponding to each motor and electronic control system is directly controlled to enter the preset different speed state or stop running state.

10. The cooling control method for a high-voltage lithium-ion electric forklift according to any one of claims 7 to 9, characterized in that: The cooling control method also includes: when it is detected that the fan is started, the solenoid valve preset at the oil circuit heat sink and the original hydraulic oil circuit is triggered to switch the hydraulic oil flow path from the original hydraulic oil circuit pipeline to the oil circuit heat sink integrated in the forklift vehicle radiator and located below the fan.

Images