A method, system, device, and medium for power control of a charger of a construction machine

Abstract

The application discloses an engineering machine charger power control method, system, device and medium, and belongs to the technical field of engineering machines. The engineering machine charger power control method comprises the following steps: determining the hardware parameters of the charger; wherein the hardware parameters comprise the plug-in times of each gun and the state information of each cable; the state information comprises the current temperature, the over-temperature times and the three-phase current value; the over-temperature times are the times that the cable temperature exceeds the temperature threshold; calculating the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable according to the hardware parameters; calculating the total allowable current value of the cable according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient; and controlling the charger to supply power to the engineering machine according to the total allowable current value of the cable. The application can reasonably control the charger power of the engineering machine and avoid cable overload.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of engineering machinery, in particular to a charger power control method, system, device and medium of engineering machinery. BACKGROUND

[0002] The engineering machinery such as excavators and rotary drilling rigs has dual needs of parking charging and charging during work, and the charging power of the engineering machinery is large. Influenced by factors such as the plug-in times of the charger gun, the charging current setting value, the cable overload condition is prone to occur, which seriously affects the construction safety and work efficiency.

[0003] Therefore, how to reasonably control the charger power of the engineering machinery and avoid cable overload is a technical problem to be solved by the person skilled in the art at present. SUMMARY

[0004] The application aims to provide a charger power control method, system, device and medium of engineering machinery, which can reasonably control the charger power of the engineering machinery and avoid cable overload.

[0005] To solve the above technical problems, the application provides a charger power control method of engineering machinery, which is applied to a vehicle controller of the engineering machinery, and the engineering machinery further comprises a power battery pack, a motor controller and a load motor; when a charger gun of a charger is connected with the engineering machinery, the power battery pack and the motor controller are connected with the charger through a direct current bus respectively, the charger is connected with a three-phase alternating current power supply through N cables, and the charger power control method of the engineering machinery comprises the following steps:

[0006] determining hardware parameters of the charger; wherein the hardware parameters comprise plug-in times of each charger gun and state information of each cable; the state information comprises a current temperature, a temperature exceeding number and a three-phase current value; the temperature exceeding number is the number of times that the cable temperature exceeds a temperature threshold value;

[0007] calculating a temperature attenuation coefficient, an aging coefficient and a three-phase imbalance correction coefficient of each cable according to the hardware parameters;

[0008] calculating a total allowable current value of the cable according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient;

[0009] controlling the charger to supply power to the engineering machinery according to the total allowable current value of the cable, so as to control the charger power.

[0010] Optionally, calculating a temperature attenuation coefficient, an aging coefficient and a three-phase imbalance correction coefficient of each cable according to the hardware parameters comprises:

[0011] calculating a corresponding temperature attenuation coefficient according to a current temperature of each of the cables;

[0012] calculating a corresponding aging coefficient according to a number of over-temperature times of each of the cables and a number of plug-in times of a plug-in gun currently connected to the construction machinery;

[0013] calculating a corresponding three-phase imbalance correction coefficient according to a three-phase current value of each of the cables.

[0014] Optionally, controlling the charger to supply power to the construction machinery according to the total cable allowable current value comprises:

[0015] determining a battery allowable charging current value of the power battery pack;

[0016] determining a target charging current value according to the total cable allowable current value and the battery allowable charging current value;

[0017] controlling the charger to supply power to the construction machinery according to the target charging current value.

[0018] Optionally, determining a target charging current value according to the total cable allowable current value and the battery allowable charging current value comprises:

[0019] determining a working state of the load motor according to a current current value of the motor controller;

[0020] if the load motor is in a power consumption state, setting a minimum value between the total cable allowable current value and the battery allowable charging current value as the target charging current value;

[0021] if the motor controller is in an energy recovery state, subtracting a reference current value from the battery allowable charging current value to obtain an alternative current value, and setting a minimum value between the alternative current value and the total cable allowable current value as the target charging current value; wherein the reference current value is an absolute value of the current current value of the motor controller.

[0022] Optionally, calculating the total cable allowable current value according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient comprises:

[0023] determining a rated current value of each of the cables;

[0024] calculating a single-cable allowable current value of each of the cables according to the rated current value, the temperature attenuation coefficient and the aging coefficient;

[0025] adding up the single-cable allowable current values of all the cables to obtain a total current value;

[0026] a product of the user-set charging current value and the three-phase imbalance correction coefficient as a second current value;

[0027] a product of the user-set charging current value and the three-phase imbalance correction coefficient as a second current value;

[0028] a product of the user-set charging current value and the three-phase imbalance correction coefficient as a second current value.

[0029] Optionally, the application further comprises:

[0030] determining a maximum output current of the charging machine;

[0031] determining whether the load current of the load machine is less than or equal to the maximum output current of the charging machine;

[0032] if yes, controlling the charging machine to supply power to the load machine and controlling the power battery pack to not supply power;

[0033] if no, controlling the charging machine and the power battery pack to jointly supply power to the load machine.

[0034] The application also provides a charging machine power control system of a construction machine, which is applied to a whole-vehicle controller of the construction machine, and the construction machine further comprises a power battery pack, a motor controller and a load machine; when a plug-in gun of a charging machine is connected to the construction machine, the power battery pack and the motor controller are connected to the charging machine through a direct-current bus respectively, the charging machine is connected to a three-phase alternating current power supply through N cables, and the charging machine power control system of the construction machine comprises:

[0035] a parameter determination module configured to determine hardware parameters of the charging machine; wherein the hardware parameters comprise a plug-in frequency of each plug-in gun and state information of each cable; the state information comprises a current temperature, a temperature-overload frequency and a three-phase current value; and the temperature-overload frequency is a frequency of cable temperature exceeding a temperature threshold value;

[0036] a coefficient calculation module configured to calculate a temperature attenuation coefficient, an aging coefficient and a three-phase imbalance correction coefficient of each cable according to the hardware parameters;

[0037] a cable total allowable current value calculation module configured to calculate a cable total allowable current value according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient;

[0038] a power supply control module configured to control the charging machine to supply power to the construction machine according to the cable total allowable current value, so as to control charging machine power.

[0039] The application further provides a storage medium, which stores a computer program, and the computer program realizes the steps of the power control method of the charger of the engineering machine when executed.

[0040] The application further provides an electronic device, which comprises a memory and a processor, and the memory stores a computer program, and the processor realizes the steps of the power control method of the charger of the engineering machine when calling the computer program in the memory.

[0041] The application provides a power control method of a charger of an engineering machine, and the engineering machine applied by the method comprises a vehicle controller, a power battery pack, a motor controller and a load motor. When a plug gun of the charger is connected with the engineering machine, the power battery pack and the motor controller are connected with the charger through a direct current bus. The plug-in times, the temperature of the cable, the aging degree and the three-phase imbalance degree all affect the carrying capacity of the cable. According to the plug-in times in the hardware parameters of the charger, the state information (the current temperature, the over-temperature times and the three-phase current value) of the cable, the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable are calculated, and then the total allowable current value of the cable is calculated according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient. The above-mentioned scheme controls the charger to supply power to the engineering machine according to the total allowable current value of the cable, so as to limit the charging current in the safe carrying range of the cable. It can be seen that the application can reasonably control the power of the charger of the engineering machine, and avoid cable overload. The application also provides a charger power control system of an engineering machine, a storage medium and an electronic device, which have the above-mentioned beneficial effects, and will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0043] Figure 1 A flow chart of the power control method of the charger of the engineering machine provided by the embodiments of the application;

[0044] Figure 2 A schematic diagram of the charging principle of the engineering machine provided by the embodiments of the application;

[0045] Figure 3 A structural schematic diagram of the power control system of the charger of the engineering machine provided by the embodiments of the application. DETAILED DESCRIPTION

[0046] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0047] Please see the following Figure 1 , Figure 1 A flow chart of a power control method of a charger of an engineering machine provided by the embodiments of the present application.

[0048] The specific steps can include:

[0049] S101: determining hardware parameters of the charger;

[0050] The embodiments can be applied to a vehicle controller of an engineering machine, the engineering machine further comprising a power battery pack, a motor controller and a load motor; the power battery pack and the motor controller are connected to the charger through a direct current bus when a plug gun of the charger is connected to the engineering machine, and the charger is connected to a three-phase alternating current power source through N cables. The charger is a component integrated in the engineering machine.

[0051] The vehicle controller can be connected to the charger and obtain the hardware parameters from the charger. The charger can have any number of plug guns and any number of cables, and the hardware parameters are parameters used to describe the state of the plug guns and the cables.

[0052] Specifically, the hardware parameters include the plug-in and plug-out times of each plug gun and the state information of each cable; the state information includes a current temperature, a number of over-temperature times and a three-phase current value; the number of over-temperature times is the number of times that the temperature of the cable exceeds a temperature threshold. The plug gun of the charger is a charging gun, and the plug-in and plug-out times are used to describe the cumulative number of operations of mechanical connection and subsequent disconnection between the plug gun and the engineering machine.

[0053] When there are multiple plug guns, the plug-in and plug-out times of the plug guns can be different; when there are multiple cables, the state information of the cables can be different.

[0054] S102: calculating a temperature attenuation coefficient, an aging coefficient and a three-phase imbalance correction coefficient of each cable according to the hardware parameters;

[0055] Wherein, after obtaining the hardware parameters, the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable can be calculated according to the hardware parameters. The temperature attenuation coefficient is a coefficient describing the decrease of the current-carrying capacity of the cable due to temperature rise, the aging coefficient is a coefficient of the remaining current-carrying capacity of the cable after insulation aging, and the three-phase imbalance correction coefficient is a coefficient of the additional heat caused by three-phase current imbalance.

[0056] S103: calculating the total cable allowable current value according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient;

[0057] Wherein, on the basis of obtaining the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient, the single-cable allowable current value of each cable can be calculated according to the rated current, the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable, and then the total cable allowable current value can be calculated in combination with the single-cable allowable current values of all cables.

[0058] S104: controlling the power supply of the engineering machinery by the charger according to the total cable allowable current value, so as to control the charger power.

[0059] Wherein, the current output value of the charger can be controlled according to the total cable allowable current value, so as to control the charger power, and then the power supply of the engineering machinery by the charger is realized. In the above process, the current output of the charger can be controlled based on the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient, so as to avoid the overload of the cable caused by overheating, insulation aging or three-phase current imbalance.

[0060] The engineering machinery to which the embodiment is applied includes a vehicle controller, a power battery pack, a motor controller and a load motor. When the plug gun of the charger is connected with the engineering machinery, the power battery pack and the motor controller are connected with the charger through a direct current bus respectively. The plug-in frequency, the temperature of the cable, the aging degree and the three-phase imbalance degree all affect the carrying capacity of the cable. In the embodiment, the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable are calculated according to the plug-in frequency in the hardware parameters of the charger and the state information (current temperature, over-temperature frequency and three-phase current value) of the cable, and then the total cable allowable current value is calculated according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient. In the above scheme, the power supply of the engineering machinery by the charger is controlled according to the total cable allowable current value, so as to limit the charging current within the safe carrying range of the cable. It can be seen that the charger power of the engineering machinery can be reasonably controlled to avoid the overload of the cable.

[0061] as for Figure 1Further to the embodiments, the process of calculating the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable according to the hardware parameters includes: calculating the temperature attenuation coefficient (i.e., cable temperature attenuation coefficient) of each cable according to the current temperature of the cable; calculating the aging coefficient (i.e., cable aging coefficient) of each cable according to the number of over-temperature times of the cable and the number of plug-in times of the plug-in gun currently connected to the construction machinery; and calculating the three-phase imbalance correction coefficient of each cable according to the three-phase current value of the cable.

[0062] Specifically, the process of calculating the temperature attenuation coefficient is as follows:

[0063] In the above formula, represents the current temperature of the cable, represents the temperature in Celsius.

[0064] Specifically, the process of calculating the aging coefficient is as follows:

[0065] ; represents the number of plug-in times, represents the number of over-temperature times (i.e., over-temperature event count).

[0066] Specifically, the three-phase current value of the cable includes the first-phase current , the second-phase current , and the third-phase current . The process of calculating the three-phase imbalance correction coefficient of each cable according to the three-phase current value of the cable is as follows:

[0067] According to the average value of the three-phase current of the cable ;

[0068] A three-phase imbalance threshold (e.g., 5%) is set;

[0069] The three-phase imbalance is calculated, and max represents the maximum value;

[0070] If ≤ , it is determined that the three-phase current is balanced, and the three-phase imbalance correction coefficient is equal to 1 at this time;

[0071] If > , it is determined that the three-phase current is unbalanced, and the three-phase imbalance correction coefficient is calculated according to the three-phase imbalance, and the three-phase imbalance is positively correlated with the three-phase imbalance correction coefficient. When the three-phase current is unbalanced, the current can be adjusted or an alarm can be issued to remind the inspection of the cable connection and the load condition.

[0072] As for the Figure 1 For further introduction of the corresponding embodiment, the process of calculating the total cable allowable current value according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient includes the following steps:

[0073] Step A1: determining the rated current value of each of the cables (i.e., single cable rated current value);

[0074] Step A2: calculating the single cable allowable current value of each of the cables according to the rated current value, the temperature attenuation coefficient and the aging coefficient;

[0075] Specifically, the single cable allowable current value can be obtained by multiplying the rated current value, the temperature attenuation coefficient and the aging coefficient ,

[0076] Step A3: adding the single cable allowable current values of all the cables to obtain a total current value

[0077] Step A4: taking the product of the total current value and the three-phase imbalance correction coefficient as a first current value;

[0078] Step A5: taking the product of the user-set charging current value and the three-phase imbalance correction coefficient as a second current value;

[0079] Step A6: taking the minimum value between the first current value and the second current value as a reference current value, and setting the product of the reference current value and a safety coefficient as the total cable allowable current value.

[0080] When the three-phase current is unbalanced, the charging current is reduced to ensure safety. The embodiment introduces an imbalance correction coefficient (0 ≤1), which is determined according to the degree of imbalance. The larger the degree of imbalance, the smaller the imbalance correction coefficient , so as to calculate the charging current.

[0081] Specifically, the calculation formula of the first current value is ; and the calculation formula of the second current value is .

[0082] When the three-phase current is balanced (i.e., ≤ ), the three-phase imbalance correction coefficient is equal to 1, and the first current value is equal to​​​ Second current value equal Reference current value min( , ) When the three-phase current is unbalanced (i.e. > When ), the reference current value for min means taking the minimum value. This represents the safety factor. The safety factor can be 0.9. The above methods yield the total allowable current value for the cable while maintaining a certain safety margin.

[0083] As for Figure 1 In a further description of the corresponding embodiment, this embodiment can control the charger to supply power to the construction machinery based on the total allowable current value of the cable in the following way: determining the allowable charging current value of the power battery pack (i.e., the maximum allowable charging current value of the battery). According to the total allowable current value of the cable and the battery's allowable charging current value Determine the target charging current value Control the charger to charge according to the target charging current value. The aforementioned engineering machinery is powered. The allowable charging current value of the battery can be determined based on the remaining battery capacity and cell temperature.

[0084] Furthermore, the process of determining the target charging current value based on the total allowable current value of the cable and the allowable charging current value of the battery includes:

[0085] The operating state of the load motor is determined based on the current current value of the motor controller;

[0086] If the load motor is in a powered state, then the total allowable current value of the cable is... and the battery's allowable charging current value The minimum value in is set as the target charging current value. ;

[0087] If the motor controller is in energy recovery mode, then the battery's allowable charging current value will be set. Subtract the reference current value Obtain alternative current values The alternative current values and the total allowable current value of the cable The minimum value in is set as the target charging current value. Wherein, the reference current value The current value of the motor controller The absolute value. The state of power consumption refers to the state in which the load motor consumes power from the battery, while the state of energy recovery refers to the state in which the load motor recovers energy to charge the battery. Specifically, if... If the value is greater than 0, the motor controller is in energy recovery mode. =min( , );like If the value is less than 0, the motor controller is in energy recovery mode. =min( , - ).

[0088] As for Figure 1 In a further description of the corresponding embodiment, this embodiment can obtain the remaining battery power from the battery management system; obtain the load current value of the load motor from the motor controller; and perform droop control on the bus voltage of the motor controller based on the remaining battery power and the load current value.

[0089] As for Figure 1 In a further description of the corresponding embodiment, this embodiment can also determine the maximum output current of the charger; determine whether the load current of the load motor is less than or equal to the maximum output current of the charger; if so, control the charger to supply power to the load motor and control the power battery pack not to supply power; if not, control the charger and the power battery pack to jointly supply power to the load motor.

[0090] In related technologies, estimating cable current carrying capacity solely based on factory ratings or static temperature rise curves cannot dynamically reflect actual operating conditions such as insertion and removal wear, local bulging, and three-phase imbalance. To address the technical problems existing in the aforementioned related technologies, this embodiment offers the following solution: a real-time digital twin model is established for each cable, and the digital twin model is driven by data such as temperature, current, and bending radius. The remaining current carrying capacity and remaining lifespan of the cable are output in real time using the driving digital twin model, and the charger output current is adjusted in a closed loop accordingly to prevent overload and avoid excessive derating.

[0091] The process described in the above embodiments is illustrated below through examples in practical applications.

[0092] Electric vehicles generally use two charging methods, the first is direct current fast charging, which uses an independent charging circuit, and the power grid alternating current is converted into direct current through the charging pile, and then directly connected to the battery through the charging gun. The second is alternating current slow charging, which uses single-phase alternating current to charge the battery through the vehicle-mounted charging machine AC / DC. Both charging methods can only be used for stationary charging, while construction machinery not only needs to achieve the function of stationary charging, but also needs to be charged while working. At present, the direct current charging facilities for pure electric and plug-in hybrid construction machinery are not perfect, so three-phase alternating current charging method is mostly used. In summary, there are essential differences between construction machinery and electric vehicles in terms of work scene and working condition requirements. The existing charging and control system from the field of electric vehicles cannot meet the complex and variable requirements of construction machinery.

[0093] The typical power range of construction machinery is 50-300 kW, which is about 3-5 times the power of an automobile charging machine. Construction machinery requires a large amount of charging power, and the equipment moves frequently during charging, requiring frequent plugging and unplugging of the charging gun. The resistance of the charging gun increases due to excessive plugging and unplugging, or the allowed charging current is set incorrectly by hand, or the actual power supply switch on site does not match the design, causing cable overload risk. The existing charging system cannot accurately determine the overload condition of the charging cable in real time, especially when multiple cables are used for power supply, it cannot identify and intelligently reduce the charging current in advance. The construction machinery charging system needs to consider the real-time power demand of dynamic loads such as hydraulic pumps, generators, and energy recovery, which is quite different from the relatively simple control requirements of electric vehicles. The current system lacks an energy distribution system, and when the charging process conflicts with the load power supply demand, there is a lack of intelligent and effective arbitration mechanism. For example, when the battery charging and the winch motor are operating at the same time, it may cause the risk of battery overcharge. In addition, the existing system also lacks mode switching. When charging, the charging machine cannot directly power the load, and when the battery is fully charged, the charging machine stops, at which time the load power supply completely depends on the battery, which will undoubtedly cause the battery to frequently experience charging and discharging cycles, thereby accelerating the aging of the battery and shortening the service life of the battery.

[0094] To solve the technical problems existing in the above-mentioned related solutions, the present embodiment provides a construction machinery charging control scheme, which includes a main circuit system and a signal control system.

[0095] The main circuit system is introduced as follows: three-phase alternating current passes through the socket box in a parallel manner through a single or multiple cables, is connected to the leakage protection module, the output end of the leakage module is connected to the OBC (On-Board Charger, vehicle-mounted charger) charging module, the output of the OBC charging module is connected to the DC bus, and the power battery pack is connected to the DC bus, forming a parallel power supply architecture with the charging module. The load motor is connected to the DC bus through the motor controller. The DC converter DCDC (i.e. converter) and auxiliary equipment are directly connected to the DC bus. The main circuit system supports three different energy distribution modes: charging priority, load priority and hybrid power supply.

[0096] The signal monitoring and control system is introduced as follows: in addition to being able to feedback the connection state signal of the plug gun, the socket box is also configured with a temperature sensor for monitoring the temperature change of the cable joint, and is also provided with a current transformer for detecting the current of each line in each charging cable. The vehicle control unit (VCU) realizes communication. On the one hand, the vehicle control unit can control and interact with the charger, and can adjust the charging current in real time according to the load demand, realizing dynamic power coordination; on the other hand, the vehicle control unit can also interact with the battery management system (BMS, Battery Management System) to obtain key information such as SOC (State of Charge, battery remaining capacity) and allowed charging current. The man-machine interaction module can manually set the maximum allowed charging current according to the actual available charging current (or power) of the on-site power distribution system.

[0097] The scheme solves the core pain points in the high-power charging scene of engineering machinery through control logic and hardware design. Specifically, the embodiment can reduce the risk of cable overload, and through the dynamic bus voltage setting strategy and the hybrid control mode based on current priority, the number of battery charge and discharge cycles and the SOC fluctuation are reduced, the battery overcharge and overdischarge are avoided, the service life of the battery is effectively prolonged, and the use cost of the electric vehicle is reduced. In the embodiment, the charger directly supplies power to the load, reducing energy conversion loss. The vehicle-mounted energy system can flexibly adjust according to the battery state and load demand, enhancing the reliability and stability of the system and improving the user experience.

[0098] Please refer to Figure 2 , Figure 2The engineering machinery charging principle diagram provided by the embodiment of the application is shown in the figure, which shows three-phase alternating current power supply, socket box, leakage protection module, OBC charging module, charger controller, vehicle controller (VCU), battery management system (BMS), power battery pack, motor controller, DC converter, motor and man-machine interaction module. The socket box can transmit the plug number, temperature and current signal to the charger controller, the CAN signal is transmitted between the charger controller and the OBC charging module, the vehicle controller (VCU) is in communication connection with the charger controller, the battery management system (BMS), the man-machine interaction module and the motor controller, and the battery management system (BMS) can collect data from the power battery pack. The charger includes: three-phase alternating current power supply, socket box, leakage protection module, OBC charging module and charger controller. The engineering machinery includes: vehicle controller (VCU), battery management system (BMS), power battery pack, motor controller, DC converter and man-machine interaction module. In addition, the embodiment can also not set the charger controller in the charger, and the signal is directly transmitted to the vehicle controller (VCU), and the charger is directly controlled by the vehicle controller (VCU).

[0099] The cable overload prevention control process in the scheme is as follows:

[0100] Step B1: Vehicle controller signal acquisition.

[0101] The charger controller receives the connection signal of the charging gun plug and the socket, and counts the plug-in frequency of each plug according to the connection signal, the temperature sensor signal installed on each socket of the socket box, and the three-phase current sensor signal installed on each socket in the socket box, the vehicle controller obtains the number N of inserted cables given by the charger controller through communication, the cable temperature value transmitted by the temperature sensor on the socket box , and the three-phase current value obtained by the current sensor on the cable in real time , , .

[0102] The man-machine interaction module can manually set the maximum allowed charging current according to the actual available charging current (or power) of the on-site power distribution system, and the vehicle controller obtains the user-set charging current .

[0103] Step B2: Calculate the cable temperature attenuation coefficient .

[0104] The cable temperature attenuation coefficient is calculated by the cable temperature. When the cable temperature is less than 25 degrees Celsius, the cable temperature attenuation coefficient is 1, and when the cable temperature is higher, the cable temperature attenuation coefficient decreases until 0.

[0105] Step B3: Calculate the cable aging coefficient .

[0106] When the plug is connected to the engineering machinery, the vehicle controller will add 1 to the number of times the charging gun is plugged in. This step can first count the number of times the charging gun is plugged in Calculate, secondly count the number of times the cable over-temperature, record the number of times the cable exceeds the over-temperature threshold as The cable aging coefficient is calculated according to the number of times the cable is plugged in and the number of times the cable over-temperature, when the number of times the cable is plugged in and the number of times the cable over-temperature increases, the cable aging coefficient gradually decreases from 1 to 0.

[0107] Step B4: Calculate the total current value .

[0108] According to the cable model, the cable rated current is queried, and the total current value is obtained by using the cable rated current, the cable temperature coefficient, the cable aging coefficient and the number of inserted cables.

[0109] Step B5: Calculate the unbalance correction coefficient .

[0110] By real-time acquisition of three-phase current value, the average value of three-phase current is calculated, and the three-phase unbalance degree is calculated, when the three-phase unbalance degree is greater than the set three-phase unbalance degree threshold, the three-phase current unbalance is judged. When the three-phase current is unbalanced, in order to ensure safety, the charging current is reduced. An unbalance correction coefficient The unbalance correction coefficient is determined according to the unbalance degree, the larger the unbalance degree The smaller.

[0111] Step B6: Calculate the total allowable current value of the cable after retaining a certain safety factor .

[0112] When the three-phase is balanced, the cable allowable charging current is the product of the minimum value of the user set charging current and the total current value and the safety factor; when the three-phase is unbalanced, the total allowable current value of the cable is the product of the minimum value of the user set charging current and the total current value and the safety factor and the unbalance correction coefficient.

[0113] The above scheme can effectively solve the problem of over-limit heating or protection failure caused by manual setting error or excessive plug-in times of the connector, which leads to resistance increase, or the actual power supply switch in the field does not match the design, ensuring the safe operation of the cable during charging and avoiding the risk of cable overload.

[0114] The charging current dynamic control process in the present scheme is as follows:

[0115] The battery management system determines the maximum allowed charging current of the battery pack according to the remaining battery capacity and the cell temperature, and the vehicle controller obtains the maximum allowed charging current value of the battery through communication ; the vehicle controller obtains the real-time current value of the motor controller through communication in real time .

[0116] When >0, it indicates that the motor controller is in the power consumption state, at this time the final charging current (i.e. the target charging current value) =min( , ). Through the above-mentioned manner, it can be ensured that the maximum allowed charging current of the battery is not exceeded while meeting the load demand of the motor, thereby guaranteeing the safe charging of the battery.

[0117] When <0, it indicates that the motor controller is in the energy recovery state, at this time the final charging current =min( , - ); wherein is the absolute value of the bus current, and this calculation manner can reasonably allocate the current for energy recovery, thereby avoiding excessive impact on the battery. Through this manner, the real-time optimal allocation of the charging current and the load demand is realized.

[0118] The above-mentioned scheme realizes the real-time optimal allocation of the charging current and the load demand, prevents overcharging of the battery, and at the same time accelerates the charging speed of the battery.

[0119] In the present scheme, the battery life optimization control process is as follows:

[0120] The vehicle controller obtains the remaining battery capacity (SOC) and the battery voltage from the battery management system (BMS) through communication ; the vehicle controller obtains the bus voltage of the motor controller from the motor controller through communication ; the vehicle controller obtains the output current of the charger (i.e. the actual output current value of the charger) from the charger controller through communication ;

[0121] The dynamic bus voltage setting strategy is as follows:

[0122] Based on the voltage-current droop control method, a droop characteristic curve is designed for the charger:

[0123] ; is the reference voltage (determined by SOC and load), k is the droop coefficient, is the output current of the charger.

[0124] The method for controlling the droop of the motor controller's bus voltage based on the remaining battery power and the load current value is as follows:

[0125] If the remaining battery charge is in the low SOC range (e.g., SOC < 30%), improve The charger prioritizes charging the battery (even under light load). The remaining battery capacity and... Negative correlation.

[0126] If the remaining battery charge is in the mid-SOC range (e.g., 30% ≤ SOC < 80%), adjust dynamically according to the load. (Increase when the load is high) This allows the charger to handle most of the load current.

[0127] If the remaining battery charge is in the high SOC range (e.g., 80% ≤ SOC < 95%), reduce This allows the battery to discharge slightly in order to maintain SOC stability.

[0128] If the remaining battery charge is in the extremely high SOC range (e.g., 95% ≤ SOC ≤ 100%), control Reduce the voltage to the battery voltage; when the battery is close to full charge, reduce the bus voltage to avoid overcharging, reduce the number of battery cycles, and extend battery life.

[0129] The above solution can avoid unnecessary charge-discharge cycles after the battery is fully charged, thereby extending the battery's lifespan and reducing equipment maintenance costs.

[0130] By using droop control, the charger can dynamically adjust the output voltage according to load demand and battery SOC, so that the system can prioritize the use of charger energy to charge the battery under light load and reasonably allocate power under heavy load, thereby reducing the number of battery charge and discharge cycles and SOC fluctuations.

[0131] In this embodiment, the hybrid control process based on current priority is as follows:

[0132] Set the charger's maximum output current (Determined by hardware capabilities).

[0133] When the load current ≤ :

[0134] The charger is powered independently, and the bus voltage is set by the charger. The battery does not operate.

[0135] When the load current > :

[0136] Charger output Residual current ( ) provided by the battery, in which case the bus voltage is determined by the battery voltage.

[0137] The scheme can meet the requirements of charging the construction machinery when it is stopped or working, and supplying power to the construction machinery through a three-phase alternating current power supply, thereby realizing the high-power charging function of the construction machinery.

[0138] Please refer to Figure 3 , Figure 3 The system can be applied to the whole vehicle controller of the construction machinery, and the construction machinery further comprises a power battery pack, a motor controller and a load motor. When the plug gun of the charger is connected to the construction machinery, the power battery pack and the motor controller are connected to the charger through a direct current bus respectively, the charger is connected to a three-phase alternating current power supply through N cables, and the charger power control system of the construction machinery comprises:

[0139] A parameter determination module is configured to determine the hardware parameters of the charger. The hardware parameters comprise the plug-in and plug-out times of each plug gun and the state information of each cable. The state information comprises the current temperature, the over-temperature times and the three-phase current values. The over-temperature times refer to the number of times that the temperature of the cable exceeds the temperature threshold.

[0140] A coefficient calculation module is configured to calculate the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable according to the hardware parameters.

[0141] A cable total allowable current value calculation module is configured to calculate the cable total allowable current value according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient.

[0142] A power supply control module is configured to control the charger to supply power to the construction machinery according to the cable total allowable current value, so as to control the charger power.

[0143] ​The construction machinery applied in the embodiment comprises a vehicle controller, a power battery pack, a motor controller and a load motor, and the power battery pack and the motor controller are respectively connected with the charger through a direct current bus when the plug gun of the charger is connected with the construction machinery. The plug-in times, the temperature of the cable, the aging degree and the three-phase imbalance degree all affect the carrying capacity of the cable. The temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable are calculated according to the plug-in times in the hardware parameters of the charger and the state information (the current temperature, the over-temperature times and the three-phase current value) of the cable, and then the total allowable current value of the cable is calculated according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient. The above scheme controls the charger to supply power to the construction machinery according to the total allowable current value of the cable, so as to limit the charging current within the safe carrying range of the cable. It can be seen that the embodiment can reasonably control the power of the charger of the construction machinery and avoid cable overload.

[0144] Optionally, the process of calculating the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable by the coefficient calculation module according to the hardware parameters comprises: calculating the corresponding temperature attenuation coefficient according to the current temperature of each cable; calculating the corresponding aging coefficient according to the over-temperature times of each cable and the plug-in times of the plug gun currently connected with the construction machinery; and calculating the corresponding three-phase imbalance correction coefficient according to the three-phase current value of each cable.

[0145] Further, the process of controlling the charger to supply power to the construction machinery according to the total allowable current value of the cable by the power supply control module comprises: determining the battery allowable charging current value of the power battery pack; determining the target charging current value according to the total allowable current value of the cable and the battery allowable charging current value; and controlling the charger to supply power to the construction machinery according to the target charging current value.

[0146] Further, the process of determining the target charging current value according to the total allowable current value of the cable and the battery allowable charging current value by the power supply control module comprises: determining the working state of the load motor according to the current value of the motor controller; if the load motor is in the power consumption state, setting the minimum value of the total allowable current value of the cable and the battery allowable charging current value as the target charging current value; if the motor controller is in the energy recovery state, obtaining an alternative current value by subtracting a reference current value from the battery allowable charging current value, and setting the minimum value of the alternative current value and the total allowable current value of the cable as the target charging current value; wherein the reference current value is the absolute value of the current value of the motor controller.

[0147] Further, the process of calculating the total cable allowable current value by the cable total allowable current value calculation module according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient comprises: determining the rated current value of each cable; calculating the single cable allowable current value of each cable according to the rated current value, the temperature attenuation coefficient and the aging coefficient; adding the single cable allowable current values of all the cables to obtain a total current value; taking the product of the total current value and the three-phase imbalance correction coefficient as a first current value; taking the product of the user-set charging current value and the three-phase imbalance correction coefficient as a second current value; taking the minimum value between the first current value and the second current value as a reference current value, and setting the product of the reference current value and a safety coefficient as the total cable allowable current value.

[0148] Further, the system further comprises:

[0149] The droop control module is configured to acquire the battery residual capacity from the battery management system, and to acquire the load current value of the load motor from the motor controller, and to perform droop control on the bus voltage of the motor controller according to the battery residual capacity and the load current value.

[0150] Further, the power supply control module is further configured to determine the maximum output current of the charger, and to determine whether the load current of the load motor is less than or equal to the maximum output current of the charger, and if yes, to control the charger to supply power to the load motor and control the power battery pack not to supply power, and if no, to control the charger and the power battery pack to jointly supply power to the load motor.

[0151] Since the embodiments of the system part correspond to the embodiments of the method part, the embodiments of the system part are described in the description of the embodiments of the method part, and are not described here in detail.

[0152] The application further provides a storage medium having a computer program stored thereon, and the computer program can implement the steps provided by the above embodiments when executed. The storage medium can include a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0153] The application further provides an electronic device, which can include a memory and a processor, the memory has a computer program stored therein, and the processor can implement the steps provided by the above embodiments when invoking the computer program in the memory. Of course, the electronic device can further include various network interfaces, power supplies and other components.

[0154] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

[0155] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A method of power control of a charger of a construction machine, characterized by, The application relates to a power controller of an engineering machine, wherein the engineering machine further comprises a power battery pack, a motor controller and a load motor; the power battery pack and the motor controller are connected with a charger through a direct current bus when a plug of the charger is connected with the engineering machine; the charger is connected with a three-phase alternating current power source through N cables; and a power control method of the charger of the engineering machine comprises the following steps: determining hardware parameters of the charger; wherein the hardware parameters comprise a plug-in and plug-out times of each plug and state information of each cable; the state information comprises a current temperature, a temperature overproof times and a three-phase current value; and the temperature overproof times is the times of cable temperature exceeding a temperature threshold value; calculating a temperature attenuation coefficient, an aging coefficient and a three-phase imbalance correction coefficient of each cable according to the hardware parameters; calculating a total allowed current value of the cables according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient; controlling the charger to supply power to the engineering machine according to the total allowed current value of the cables, so as to control the power of the charger.

2. The method of power control of a charger of a construction machine according to claim 1, characterized by, The method for calculating the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient of each cable according to the hardware parameters comprises the following steps: calculating a corresponding temperature attenuation coefficient according to a current temperature of each cable; calculating a corresponding aging coefficient according to the temperature overproof times of each cable and the plug-in and plug-out times of the plug connected with the engineering machine; calculating a corresponding three-phase imbalance correction coefficient according to a three-phase current value of each cable.

3. The method of power control of a charger of a construction machine according to claim 1, characterized by, The method for controlling the charger to supply power to the engineering machine according to the total allowed current value of the cables comprises the following steps: determining a battery allowed charging current value of the power battery pack; determining a target charging current value according to the total allowed current value of the cables and the battery allowed charging current value; controlling the charger to supply power to the engineering machine according to the target charging current value.

4. The power control method of the charger of the construction machine according to claim 3, characterized by, The method for determining the target charging current value according to the total allowed current value of the cables and the battery allowed charging current value comprises the following steps: determining a working state of the load motor according to a current value of the motor controller; if the load motor is in a power consumption state, setting the minimum value of the total allowed current value of the cables and the battery allowed charging current value as the target charging current value; if the motor controller is in an energy recovery state, subtracting a reference current value from the battery allowed charging current value to obtain an alternative current value, and setting the minimum value of the alternative current value and the total allowed current value of the cables as the target charging current value; wherein the reference current value is the absolute value of the current value of the motor controller.

5. The method of power control of a charger of a construction machine according to claim 1, characterized by, The method for calculating the total allowed current value of the cables according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient comprises the following steps: determining a rated current value of each cable; calculating a single cable allowed current value of each cable according to the rated current value, the temperature attenuation coefficient and the aging coefficient; adding the single cable allowed current values of all the cables to obtain a total current value; taking the product of the total current value and the three-phase imbalance correction coefficient as a first current value; a product of a user-set charging current value and the three-phase imbalance correction coefficient as a second current value; a minimum value of the first current value and the second current value as a reference current value, and setting a product of the reference current value and a safety coefficient as the cable total allowable current value.

6. The method of power control for a charger of a construction machine according to claim 1, characterized by, Further comprising: obtaining a battery remaining capacity from a battery management system; obtaining a load current value of the load motor from the motor controller; performing droop control on a bus voltage of the motor controller according to the battery remaining capacity and the load current value.

7. The method of power control for a charger of a construction machine according to claim 1, characterized by, Further comprising: determining a maximum output current of the charger; determining whether the load current of the load motor is less than or equal to the maximum output current of the charger; if yes, controlling the charger to supply power to the load motor and controlling the power battery pack to not supply power; if no, controlling the charger and the power battery pack to jointly supply power to the load motor.

8. A charger power control system for a construction machine, characterized by, The whole vehicle controller applied to the engineering machinery further comprises a power battery pack, a motor controller and a load motor; when a plug gun of a charger is connected with the engineering machinery, the power battery pack and the motor controller are connected with the charger through a direct current bus respectively; the charger is connected with a three-phase alternating current power source through N cables; the charger power control system of the engineering machinery comprises: a parameter determination module configured to determine hardware parameters of the charger; wherein the hardware parameters comprise plug-in times of each plug gun and state information of each cable; the state information comprises a current temperature, a number of over-temperature times and three-phase current values; the number of over-temperature times is a number of times that the temperature of the cable exceeds a temperature threshold; a coefficient calculation module configured to calculate a temperature attenuation coefficient, an aging coefficient and a three-phase imbalance correction coefficient of each cable according to the hardware parameters; a cable total allowable current value calculation module configured to calculate a cable total allowable current value according to the temperature attenuation coefficient, the aging coefficient and the three-phase imbalance correction coefficient; a power supply control module configured to control the charger to supply power to the engineering machinery according to the cable total allowable current value, so as to control charger power.

9. An electronic device, comprising: The memory and the processor are included, the memory has the computer program stored therein, and the processor realizes the steps of the charger power control method of the engineering machinery according to any one of claims 1 to 7 when calling the computer program in the memory.

10. A storage medium, characterized by The storage medium has computer executable instructions stored therein, and the computer executable instructions are loaded and executed by the processor, and realize the steps of the charger power control method of the engineering machinery according to any one of claims 1 to 7.

Images