Charger power control method, system and equipment for engineering machinery and medium

Abstract

The invention discloses a method, a system and equipment for controlling the power of a charger of engineering machinery and a medium, and belongs to the technical field of engineering machinery technologies. The charger power control method of the engineering machinery comprises the following steps: determining hardware parameters of a charger; wherein the hardware parameters comprise the number of times of plugging and unplugging each plug gun and the state information of each cable; the state information comprises a current temperature, over-temperature times and a three-phase current value; the over-temperature times are times that the temperature of the cable exceeds 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 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 machinery according to the total allowable current value of the cable. The charger power of the engineering machinery can be reasonably controlled, and cable overload is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of engineering machinery, and in particular to a method, system, device and medium for controlling the power of a charger of engineering machinery. Background Art

[0002] Construction machinery such as excavators and rotary drilling rigs have dual needs for charging while parked and charging while working. The charging power of construction machinery is relatively large. Affected by factors such as the number of times the charger plugs in and out and the charging current setting value, the charging cable is prone to overload, which seriously affects construction safety and work efficiency.

[0003] Therefore, how to reasonably control the charger power of engineering machinery to avoid cable overload is a technical problem that those skilled in the art currently need to solve. Summary of the Invention

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

[0005] To solve the above technical problems, the present application provides a power control method for a charger of construction machinery, which is applied to a vehicle controller of the construction machinery. The construction machinery also includes a power battery pack, a motor controller, and a load motor. When the charger's plug is connected to the construction machinery, the power battery pack and the motor controller are respectively connected to the charger via a DC bus, and the charger is connected to a three-phase AC power supply via N cables. The power control method for the charger of the construction machinery includes:

[0006] Determine the hardware parameters of the charger; wherein the hardware parameters include the number of times each plug has been plugged in and out and the status information of each cable; the status information includes the current temperature, the number of overtemperatures, and the three-phase current value; the number of overtemperatures is the number of times the cable temperature exceeds a temperature threshold;

[0007] Calculating the temperature attenuation coefficient, aging coefficient and three-phase unbalance correction coefficient of each of the cables according to the hardware parameters;

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

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

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

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

[0012] Calculating a corresponding aging coefficient based on the number of over-temperatures of each cable and the number of plugging and unplugging of a plug gun currently connected to the engineering machinery;

[0013] The corresponding three-phase unbalance correction coefficient is calculated according to the three-phase current value of each cable.

[0014] Optionally, controlling the charger to supply power to the engineering machinery according to the total allowable current value of the cable includes:

[0015] Determining an allowable charging current value of the battery of the power battery pack;

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

[0017] The charger is controlled 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 allowable current value of the cable and the allowable charging current value of the battery includes:

[0019] Determining the operating state of the load motor according to the current current value of the motor controller;

[0020] If the load motor is in a power-using state, the minimum value of the total allowable current value of the cable and the allowable charging current value of the battery is set as the target charging current value;

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

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

[0023] determining the 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 the single-cable allowable current values ​​of all the cables to obtain a total current value;

[0026] taking the product of the aggregate current value and the three-phase unbalance correction coefficient as a first current value;

[0027] The product of the charging current value set by the user and the three-phase unbalance correction coefficient is used as the second current value;

[0028] The minimum value between the first current value and the second current value is used as a reference current value, and the product of the reference current value and the safety factor is set as the total allowable current value of the cable.

[0029] Optionally, also include:

[0030] Determining the maximum output current of the charger;

[0031] Determining whether the load current of the load motor is less than or equal to the maximum output current of the charger;

[0032] If so, controlling the charger to supply power to the load motor and controlling the power battery pack to not supply power;

[0033] If not, the charger and the power battery pack are controlled to jointly supply power to the load motor.

[0034] The present application also provides a charger power control system for construction machinery, which is applied to a vehicle controller of the construction machinery. The construction machinery further includes a power battery pack, a motor controller, and a load motor. When the charger plug is connected to the construction machinery, the power battery pack and the motor controller are respectively connected to the charger via a DC bus, and the charger is connected to a three-phase AC power supply via N cables. The charger power control system for the construction machinery includes:

[0035] a parameter determination module, configured to determine hardware parameters of the charger; wherein the hardware parameters include the number of times each plug has been plugged in and out and status information of each cable; the status information includes current temperature, number of overtemperatures, and three-phase current values; the number of overtemperatures is the number of times the cable temperature exceeds a temperature threshold;

[0036] A coefficient calculation module, configured to calculate the temperature attenuation coefficient, aging coefficient, and three-phase unbalance correction coefficient of each of the cables according to the hardware parameters;

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

[0038] The power supply control module is used to control the charger to supply power to the engineering machinery according to the total allowable current value of the cable, so as to control the power of the charger.

[0039] The present application also provides a storage medium on which a computer program is stored. When the computer program is executed, the steps of the above-mentioned method for controlling the power of a charger of engineering machinery are implemented.

[0040] The present application also provides an electronic device including a memory and a processor, wherein the memory stores a computer program, and when the processor calls the computer program in the memory, the steps of the above-mentioned method for controlling the power of a charger of engineering machinery are implemented.

[0041] This application provides a method for controlling the power of a charger for construction machinery. The construction machinery to which this method applies includes a vehicle controller, a power battery pack, a motor controller, and a load motor. When the charger's plug connector is connected to the construction machinery, the power battery pack and the motor controller are each connected to the charger via a DC bus. The number of plug-in / plug-out cycles, cable temperature, aging, and three-phase imbalance all affect the cable's load capacity. This application calculates the temperature attenuation coefficient, aging coefficient, and three-phase imbalance correction factor for each cable based on the number of plug-in / plug-out cycles and cable status information (current temperature, number of overtemperatures, and three-phase current values) in the charger's hardware parameters. Furthermore, the total allowable current value of the cable is calculated based on the temperature attenuation coefficient, aging coefficient, and three-phase imbalance correction factor. This scheme controls the charger to supply power to the construction machinery based on the total allowable current value of the cable, thereby limiting the charging current to within the safe load range of the cable. Thus, this application can reasonably control the charger power of construction machinery and prevent cable overload. This application also provides a charger power control system, a storage medium, and an electronic device for construction machinery, all of which have the aforementioned beneficial effects and are not further elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0043] Figure 1 A flowchart of a charger power control method for engineering machinery provided in an embodiment of the present application;

[0044] Figure 2 A schematic diagram of the charging principle of an engineering machinery provided in an embodiment of the present application;

[0045] Figure 3 This is a structural diagram of a charger power control system for engineering machinery provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0047] See below Figure 1 , Figure 1 This is a flow chart of a charger power control method for engineering machinery provided in an embodiment of the present application.

[0048] Specific steps may include:

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

[0050] This embodiment can be applied to a vehicle controller for construction machinery, which also includes a power battery pack, a motor controller, and a load motor. When the charger's plug is connected to the construction machinery, the power battery pack and the motor controller are each connected to the charger via a DC bus, and the charger is connected to a three-phase AC power source via N cables. The charger is an integrated component of the construction machinery.

[0051] The vehicle controller can connect to a charger and obtain hardware parameters from the charger. A charger can have any number of plugs and cables, and the hardware parameters are used to describe the status of the plugs and cables.

[0052] Specifically, the hardware parameters include the number of plug-in and unplug operations for each plug gun and the status information for each cable. The status information includes the current temperature, overtemperature counts, and three-phase current values. The overtemperature counts are the number of times the cable temperature has exceeded a threshold. The plug gun of a charger is also known as a charging gun. The plug-in and unplug counts describe the cumulative number of mechanical connections and subsequent disconnections between the plug gun and the construction machinery.

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

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

[0055] After obtaining the hardware parameters, the temperature attenuation coefficient, aging coefficient, and three-phase imbalance correction coefficient of each cable can be calculated based on the hardware parameters. The temperature attenuation coefficient describes the decrease in current carrying capacity of the cable due to temperature rise, the aging coefficient describes the residual current carrying capacity of the cable after aging of the insulation, and the three-phase imbalance correction coefficient describes the additional heat caused by three-phase current imbalance.

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

[0057] Among them, based on the temperature attenuation coefficient, aging coefficient and three-phase unbalance correction coefficient, this step can calculate the single-cable allowable current value of each cable according to the rated current, temperature attenuation coefficient, aging coefficient and three-phase unbalance correction coefficient of each cable, and then calculate the total allowable current value of the cable by combining the single-cable allowable current values ​​of all cables.

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

[0059] This embodiment controls the charger's output current based on the total allowable cable current, thereby controlling the charger's power and enabling the charger to power the construction machinery. This process controls the charger's output current based on the temperature attenuation coefficient, the aging coefficient, and the three-phase imbalance correction coefficient, preventing cable overloads caused by cable overheating, insulation aging, or three-phase current imbalance.

[0060] The construction machinery used in this embodiment includes a vehicle controller, a power battery pack, a motor controller, and a load motor. When the charger's plug is connected to the construction machinery, the power battery pack and the motor controller are each connected to the charger via a DC bus. The number of plug-in / plug-out cycles, cable temperature, aging, and three-phase imbalance all affect the cable's load-carrying capacity. This embodiment calculates the temperature attenuation coefficient, aging coefficient, and three-phase imbalance correction factor for each cable based on the number of plug-in / plug-out cycles and cable status information (current temperature, number of overtemperatures, and three-phase current values) in the charger's hardware parameters. The total allowable current value of the cable is then calculated based on the temperature attenuation coefficient, aging coefficient, and three-phase imbalance correction factor. This scheme controls the charger to supply power to the construction machinery based on the total allowable current value of the cable, thereby limiting the charging current to within the safe carrying range of the cable. This embodiment can effectively control the charger power of the construction machinery and prevent cable overload.

[0061] As for Figure 1Further introduction to the corresponding embodiment, the process of calculating the temperature attenuation coefficient, aging coefficient and three-phase unbalance correction coefficient of each cable based on the hardware parameters includes: calculating the corresponding temperature attenuation coefficient (i.e., cable temperature attenuation coefficient) based on the current temperature of each cable; calculating the corresponding aging coefficient (i.e., cable aging coefficient) based on the number of over-temperature times of each cable and the number of plugging and unplugging times of the plug gun currently connected to the engineering machinery; calculating the corresponding three-phase unbalance correction coefficient based on the three-phase current value of each cable.

[0062] Specifically, calculate the temperature attenuation coefficient The process is as follows:

[0063] In the above formula, Indicates the current temperature of the cable, Indicates degrees Celsius.

[0064] Specifically, calculate the aging coefficient The process is as follows:

[0065] ; Indicates the number of plug-in and unplugging times. Indicates the number of overtemperatures (i.e., overtemperature event count).

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

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

[0068] Set the three-phase imbalance threshold (e.g. 5%);

[0069] Calculate three-phase imbalance , max means taking the maximum value;

[0070] like ≤ , then the three-phase current is judged to be balanced, and the three-phase unbalance correction coefficient is equal to 1;

[0071] like > , then the three-phase current is determined to be unbalanced, and the three-phase unbalance correction coefficient is calculated according to the three-phase unbalance degree The three-phase imbalance degree 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 you to check the cable connection and load conditions.

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

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

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

[0075] Specifically, in this embodiment, the rated current value, the temperature attenuation coefficient and the aging coefficient can be multiplied to obtain the single cable allowable current value. , ;

[0076] Step A3: Add up the single-cable allowable current values ​​of all the cables to obtain the total current value ;

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

[0078] Step A5: Set the charging current value set by the user The product of the current and the three-phase unbalance correction coefficient is used as the second current value;

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

[0080] When the three-phase current is unbalanced, the charging current is reduced to ensure safety. This embodiment introduces an unbalance correction coefficient (0 < ≤1), determined by the degree of imbalance. The greater the imbalance, smaller), in order to calculate the charging current.

[0081] Specifically, the first current value The calculation formula is ; Second current value The calculation formula is .

[0082] When the three-phase currents are balanced (i.e. ≤ ), the three-phase unbalance correction coefficient is equal to 1, the first current value equal , the second current value equal , reference current value is min( , ) When the three-phase current is unbalanced (i.e. > ), the reference current value for , min means taking the minimum value, = represents the safety factor. The safety factor can be 0.9. The above results show the total allowable current value of the cable with a certain safety margin.

[0083] As for Figure 1 Further introduction to the corresponding embodiment, this embodiment can control the charger to power the engineering machinery according to the total allowable current value of the cable in the following manner: determining the allowable charging current value of the battery 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 allowable charging current value Determine the target charging current value ; Control the charger according to the target charging current value The allowable charging current value of the battery can be determined based on the remaining battery power and the battery core temperature.

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

[0085] Determining the operating state of the load motor according to the current current value of the motor controller;

[0086] If the load motor is in power-on state, the total allowable current value of the cable and the battery allowable charging current value The minimum value is set to the target charging current value ;

[0087] If the motor controller is in the energy recovery state, the battery allowable charging current value is set to Subtract the reference current value Get the alternative current value , the alternative current value and the total allowable current value of the cable The minimum value is set to the target charging current value ; Wherein, the reference current value is the current value of the motor controller The power consumption state refers to the state in which the load motor consumes the power of the power battery, and the energy recovery state refers to the state in which the load motor recovers energy to charge the power battery. Specifically, if >0, the motor controller is in energy recovery state, then =min( , );like <0, the motor controller is in energy recovery state, then =min( , - ).

[0088] As for Figure 1 Further introduction to 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 according to the remaining battery power and the load current value.

[0089] As for Figure 1 Further introduction to the corresponding embodiment, this embodiment can also determine the maximum output current of the charger; judge 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 power the load motor and control the power battery pack to not power it; if not, control the charger and the power battery pack to jointly power the load motor.

[0090] In the related art, the cable current-carrying capacity is estimated only based on the factory rated value or the static temperature rise curve, which cannot dynamically reflect actual operating conditions such as plug-in wear, local bulging, and three-phase imbalance. In response to the technical problems existing in the above-mentioned related art, this embodiment has a processing method in this regard: 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 driven digital twin model is used to output the remaining current-carrying capacity and remaining life of the cable in real time, 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 embodiment is explained below through an embodiment in actual application.

[0092] Electric vehicles generally use two charging methods: DC fast charging, which uses an independent charging circuit. The grid's AC power is converted to DC power by a charging station and then directly connected to the battery via a charging plug. AC slow charging, onboard chargers, uses single-phase AC power to charge the battery. Both charging methods only allow for parking, but construction machinery must not only be able to charge while parked but also while operating. Currently, DC charging infrastructure for pure electric and plug-in construction machinery is incomplete, so three-phase AC charging is often used. In summary, construction machinery and electric vehicles differ fundamentally in their operating scenarios and operating requirements. Existing charging and control systems, originating from the electric vehicle industry, are unable to meet the complex and diverse requirements of construction machinery.

[0093] Construction machinery typically draws power from 50 to 300 kilowatts, roughly three to five times the power of a car charger. Construction machinery requires high charging power and is frequently moved during charging, requiring frequent plugging and unplugging of charging cables. This can lead to increased resistance, incorrectly set charging currents, or mismatched on-site power switches, leading to cable overload risks. Existing charging systems are unable to accurately detect charging cable overloads in real time, especially when multiple cables are sharing power. They are unable to proactively identify and intelligently reduce charging currents. Construction machinery charging systems must accommodate the real-time power demands of dynamic loads such as hydraulic pumps, generators, and energy recovery, which differs significantly from the more focused control requirements of electric vehicles. Current systems lack an energy distribution system, and when charging conflicts with load power requirements, there's no intelligent and effective arbitration mechanism. For example, simultaneous battery charging and winch motor operation can lead to the risk of battery overcharge. Furthermore, existing systems lack mode switching. When charging, the charger cannot directly power the load. When the battery is fully charged, the charger stops. At this time, the load power supply is completely dependent on the battery, which will undoubtedly cause the battery to undergo frequent charge and discharge cycles, thereby accelerating battery aging and shortening battery life.

[0094] In response to the technical problems existing in the above-mentioned related solutions, this embodiment provides a charging control solution for engineering machinery. This solution consists of two parts: a main circuit system and a signal control system.

[0095] The main circuit system is described as follows: Three-phase AC power passes through the socket box via a single or multiple cables in parallel, then connects to the leakage protection module. The output of the leakage protection module is connected to the on-board charger (OBC) charging module. The output of the OBC charging module is connected to the DC bus. 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 / DC converter (DCDC) and auxiliary equipment are directly connected to the DC bus. The main circuit system supports three different energy distribution modes: charge priority, load priority, and mixed power supply.

[0096] The signal monitoring and control system is described as follows: In addition to providing feedback on the plug's connection status, the socket box is equipped with a temperature sensor to monitor temperature changes in the cable connectors and a current transformer to detect the current flow in each line of each charging cable. The vehicle control unit (VCU) is implemented through communication. The VCU controls and exchanges data with the charger, adjusting the charging current in real time based on load demand and achieving dynamic power coordination. It also exchanges data with the battery management system (BMS) to obtain key information such as the state of charge (SOC) and allowable charging current. The human-machine interface module allows for manual setting of the maximum allowable charging current based on the actual charging current (or power) available from the on-site power distribution system.

[0097] This solution addresses the core pain points of high-power charging scenarios for construction machinery through control logic and hardware design. Specifically, this embodiment can reduce the risk of cable overload. Through a dynamic bus voltage setting strategy and a hybrid control mode based on current priority, this embodiment reduces the number of battery charge and discharge cycles and SOC fluctuations, avoids battery overcharge and over-discharge, effectively extends the battery life, and reduces the cost of electric vehicles. In this embodiment, the charger directly powers the load, reducing energy conversion losses. This embodiment enables the on-board energy system to flexibly adjust according to battery status and load demand, enhancing system reliability and stability and improving user experience.

[0098] See Figure 2 , Figure 2This is a schematic diagram of the charging principle for construction machinery provided by an embodiment of the present application. The diagram shows a three-phase AC power supply, a socket box, a leakage protection module, an OBC charging module, a charger controller, a vehicle control unit (VCU), a battery management system (BMS), a power battery pack, a motor controller, a DC converter, a motor, and a human-machine interface module. The socket box transmits plug number, temperature, and current signals to the charger controller. CAN signals are transmitted between the charger controller and the OBC charging module. The vehicle control unit (VCU) communicates with the charger controller, battery management system (BMS), human-machine interface module, and motor controller, respectively. The battery management system (BMS) can collect data from the power battery pack. The charger includes a three-phase AC power supply, a socket box, a leakage protection module, an OBC charging module, and a charger controller. The construction machinery also includes a vehicle control unit (VCU), a battery management system (BMS), a power battery pack, a motor controller, a DC converter, and a human-machine interface module. Furthermore, in this embodiment, the charger controller can be omitted from the charger; signals are transmitted directly to the vehicle control unit (VCU), and the charger is directly controlled by the VCU.

[0099] The control process for preventing cable overload in this solution is as follows:

[0100] Step B1: Vehicle controller signal acquisition.

[0101] The charger controller receives the connection signal between the charging gun plug and the socket, and counts the number of plug-in and unplugging of each gun 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 plugged cables given by the charger controller and the cable temperature value transmitted by the temperature sensor on the socket box through communication. , and the three-phase current values ​​obtained in real time by the current sensor on the cable 、 、 .

[0102] The human-machine interaction module can manually set the maximum allowable charging current based on the actual charging current (or power) that the on-site power distribution system can provide. The vehicle controller obtains the charging current set by the user through communication. .

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

[0104] The cable temperature attenuation coefficient is calculated based on the cable temperature. When the cable temperature is less than 25 degrees Celsius, the cable temperature attenuation coefficient is 1. When the cable temperature is higher, the cable temperature attenuation coefficient decreases until it reaches 0.

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

[0106] When the charging gun is connected to the construction machinery, the vehicle controller will count the number of times the charging gun is plugged in and out as one. Calculate, then count the number of times the cable is overheated, and record the number of times the cable exceeds the overtemperature threshold as The cable aging coefficient is calculated based on the number of cable plug-in and unplug-out times and the number of cable over-temperature times. When the number of plug-in and unplug-out times and the number of over-temperature times increase, the cable aging coefficient gradually decreases from 1 to 0.

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

[0108] Query the cable rated current of the cable according to the cable model, and use the cable rated current, cable temperature coefficient, cable aging coefficient and the number of inserted cables to obtain the total current value.

[0109] Step B5: Calculate the imbalance correction factor .

[0110] The three-phase current value is obtained in real time, and the three-phase current average value is calculated, and the three-phase imbalance is calculated. When the three-phase imbalance is greater than the set three-phase imbalance threshold, it is judged that the three-phase current is unbalanced. When the three-phase current is unbalanced, the charging current is reduced to ensure safety. An imbalance correction coefficient is introduced. The imbalance correction coefficient is determined according to the degree of imbalance. The greater the imbalance, the The smaller.

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

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

[0113] The above solution can effectively solve the problems of excessive heating or protection failure caused by manual setting errors, increased resistance after excessive plugging and unplugging of connectors, or mismatch between the actual power supply switch on site and the design when the cables are connected in parallel. It ensures the safe operation of the cables during charging and avoids the risk of cable overload.

[0114] The dynamic control process of charging current in this scheme is as follows:

[0115] The battery management system determines the maximum allowable charging current of the battery pack based on the remaining battery power and battery cell temperature. The vehicle controller obtains the maximum allowable charging current value of the battery through communication ; The vehicle controller obtains the real-time current value of the motor controller through communication .

[0116] when When >0, it indicates that the motor controller is in power-using state. At this time, the final charging current (i.e. the target charging current value) =min( , The above method can ensure that the maximum allowable charging current of the battery is not exceeded while meeting the motor load requirements, ensuring safe charging of the battery.

[0117] when <0, indicating that the motor controller is in the energy recovery state, and the final charging current =min( , - );in = is the absolute value of the bus current. This calculation method can reasonably distribute the energy recovery current to avoid excessive impact on the battery. In this way, the real-time optimal allocation of charging current and load demand is achieved.

[0118] The above solution realizes the real-time optimal allocation of charging current and load demand, preventing battery overcharging while speeding up battery charging.

[0119] The battery life optimization control process in this solution is as follows:

[0120] The vehicle controller obtains the remaining battery capacity (SOC) and battery voltage from the battery management system (BMS) through communication ; The vehicle controller obtains the motor controller bus voltage from the motor controller through communication The vehicle controller obtains the charger output current (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, Output current for the charger.

[0124] The method of performing droop control on the bus voltage of the motor controller according to the remaining battery power and the load current value is as follows:

[0125] If the remaining battery power is in the low SOC range (such as SOC < 30%), increase , forcing the charger to charge the battery first (even if the load is light). Negative correlation.

[0126] If the remaining battery capacity is in the middle SOC range (e.g. 30% ≤ SOC < 80%), the load is dynamically adjusted. (When the load is large, increase ), making the charger bear most of the load current.

[0127] If the remaining battery capacity is in the high SOC range (e.g. 80% ≤ SOC < 95%), reduce , allowing the battery to discharge a small amount to maintain SOC stability.

[0128] If the remaining battery capacity is in the ultra-high SOC range (such as 95% ≤ SOC ≤ 100%), control Reduce to 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 the battery life.

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

[0130] Through droop control, the charger can dynamically adjust the output voltage according to load demand and battery SOC, so that the system prioritizes the use of charger energy and charges the battery when the load is light, and reasonably distributes power when the load is heavy, 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 maximum output current of the charger (Determined by hardware capabilities).

[0133] When the load current ≤ :

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

[0135] When the load current > :

[0136] Charger output , residual current ( − ) is provided by the battery, and the bus voltage is determined by the battery voltage.

[0137] This solution can meet the requirements of charging engineering machinery when it is stopped or working, and realizes the high-power charging function of engineering machinery through three-phase AC power supply.

[0138] See Figure 3 , Figure 3 This is a schematic diagram of the structure of a charger power control system for construction machinery provided in an embodiment of the present application. The system can be applied to a vehicle controller of the construction machinery. The construction machinery also includes a power battery pack, a motor controller, and a load motor. When the charger plug is connected to the construction machinery, the power battery pack and the motor controller are respectively connected to the charger via a DC bus. The charger is connected to a three-phase AC power supply via N cables. The charger power control system of the construction machinery includes:

[0139] a parameter determination module, configured to determine hardware parameters of the charger; wherein the hardware parameters include the number of times each plug has been plugged in and out and status information of each cable; the status information includes current temperature, number of overtemperatures, and three-phase current values; the number of overtemperatures is the number of times the cable temperature exceeds a temperature threshold;

[0140] A coefficient calculation module, configured to calculate the temperature attenuation coefficient, aging coefficient, and three-phase unbalance correction coefficient of each of the cables according to the hardware parameters;

[0141] a cable total allowable current value calculation module, configured to calculate the cable total allowable current value based on the temperature attenuation coefficient, the aging coefficient, and the three-phase unbalance correction coefficient;

[0142] The power supply control module is used to control the charger to supply power to the engineering machinery according to the total allowable current value of the cable, so as to control the power of the charger.

[0143] The construction machinery used in this embodiment includes a vehicle controller, a power battery pack, a motor controller, and a load motor. When the charger's plug is connected to the construction machinery, the power battery pack and the motor controller are each connected to the charger via a DC bus. The number of plug-in / plug-out cycles, cable temperature, aging, and three-phase imbalance all affect the cable's load-carrying capacity. This embodiment calculates the temperature attenuation coefficient, aging coefficient, and three-phase imbalance correction factor for each cable based on the number of plug-in / plug-out cycles and cable status information (current temperature, number of overtemperatures, and three-phase current values) in the charger's hardware parameters. The total allowable current value of the cable is then calculated based on the temperature attenuation coefficient, aging coefficient, and three-phase imbalance correction factor. This scheme controls the charger to supply power to the construction machinery based on the total allowable current value of the cable, thereby limiting the charging current to within the safe carrying range of the cable. This embodiment can effectively control the charger power of the construction machinery and prevent cable overload.

[0144] Optionally, the process of the coefficient calculation module calculating the temperature attenuation coefficient, aging coefficient and three-phase unbalance correction coefficient of each cable based on the hardware parameters includes: calculating the corresponding temperature attenuation coefficient based on the current temperature of each cable; calculating the corresponding aging coefficient based on the number of over-temperatures of each cable and the number of plugging and unplugging of the plug gun currently connected to the engineering machinery; calculating the corresponding three-phase unbalance correction coefficient based on the three-phase current value of each cable.

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

[0146] Furthermore, the process of the power supply control module 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: determining the working state of the load motor based on the current current value of the motor controller; if the load motor is in a power-using state, setting the minimum value of the total allowable current value of the cable and the allowable charging current value of the battery as the target charging current value; if the motor controller is in an energy recovery state, subtracting the reference current value from the allowable charging current value of the battery to obtain an alternative 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 current value of the motor controller.

[0147] Furthermore, the process of the cable total allowable current value calculation module calculating the cable total allowable current value based on the temperature attenuation coefficient, the aging coefficient and the three-phase unbalance correction coefficient includes: determining the rated current value of each cable; calculating the single-cable allowable current value of each cable based on 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 unbalance correction coefficient as the first current value; taking the product of the charging current value set by the user and the three-phase unbalance correction coefficient as the second current value; taking the minimum value between the first current value and the second current value as the reference current value, and setting the product of the reference current value and the safety factor as the cable total allowable current value.

[0148] Furthermore, it also includes:

[0149] A droop control module is used to obtain the remaining battery power from the battery management system; is also used to obtain the load current value of the load motor from the motor controller; and is also used to perform droop control on the bus voltage of the motor controller according to the remaining battery power and the load current value.

[0150] Furthermore, the power supply control module is also used to determine the maximum output current of the charger; and is also used to determine whether the load current of the load motor is less than or equal to the maximum output current of the charger; if so, the charger is controlled to supply power to the load motor and the power battery pack is controlled not to supply power; if not, the charger and the power battery pack are controlled to jointly supply power to the load motor.

[0151] Since the embodiments of the system part correspond to the embodiments of the method part, please refer to the description of the embodiments of the method part for the embodiments of the system part, and will not be repeated here.

[0152] This application also provides a storage medium having a computer program stored thereon. When executed, the computer program can implement the steps provided in the above embodiments. The storage medium may include: a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, an optical disk, or other medium capable of storing program code.

[0153] The present application also provides an electronic device that may include a memory and a processor, wherein the memory stores a computer program, and when the processor calls the computer program in the memory, the steps provided in the above embodiment can be implemented. Of course, the electronic device may also include various network interfaces, a power supply, and other components.

[0154] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the scope of protection of this application.

[0155] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

Claims

1. A method for controlling the power of a charger for construction machinery, characterized in that: A vehicle controller for construction machinery, the construction machinery further comprising a power battery pack, a motor controller, and a load motor; when a charger plug is connected to the construction machinery, the power battery pack and the motor controller are respectively connected to the charger via a DC bus, and the charger is connected to a three-phase AC power supply via N cables. A power control method for the charger of the construction machinery includes: Determine the hardware parameters of the charger; wherein the hardware parameters include the number of times each plug has been plugged in and out and the status information of each cable; the status information includes the current temperature, the number of overtemperatures, and the three-phase current value; the number of overtemperatures is the number of times the cable temperature exceeds a temperature threshold; Calculating the temperature attenuation coefficient, aging coefficient and three-phase unbalance correction coefficient of each of the cables 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 unbalance correction coefficient; The charger is controlled to supply power to the engineering machinery according to the total allowable current value of the cable, so as to control the power of the charger.

2. The method for controlling the power of a charger for construction machinery according to claim 1, characterized in that: Calculating the temperature attenuation coefficient, aging coefficient, and three-phase unbalance correction coefficient of each cable according to the hardware parameters, including: Calculating a corresponding temperature attenuation coefficient according to the current temperature of each of the cables; Calculating a corresponding aging coefficient based on the number of over-temperatures of each cable and the number of plugging and unplugging of a plug gun currently connected to the engineering machinery; The corresponding three-phase unbalance correction coefficient is calculated according to the three-phase current value of each cable.

3. The method for controlling the power of a charger for construction machinery according to claim 1, wherein: Controlling the charger to supply power to the engineering machinery according to the total allowable current value of the cable includes: Determining an allowable charging current value of the battery of the power battery pack; Determining a target charging current value according to the total allowable current value of the cable and the allowable charging current value of the battery; The charger is controlled to supply power to the construction machinery according to the target charging current value.

4. The method for controlling the power of a charger for construction machinery according to claim 3, wherein: Determining a target charging current value according to the total allowable current value of the cable and the allowable charging current value of the battery includes: Determining the operating state of the load motor according to the current current value of the motor controller; If the load motor is in a power-using state, the minimum value of the total allowable current value of the cable and the allowable charging current value of the battery is set as the target charging current value; If the motor controller is in the energy recovery state, the battery allowable charging current value is subtracted from the reference current value to obtain an alternative current value, and the minimum value of the alternative current value and the total allowable current value of the cable is set as the target charging current value; wherein, the reference current value is the absolute value of the current current value of the motor controller.

5. The method for controlling the power of a charger for construction machinery according to claim 1, wherein: Calculating a total allowable current value of the cable according to the temperature attenuation coefficient, the aging coefficient, and the three-phase unbalance correction coefficient includes: determining the rated current value of each of the cables; 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; Adding the single-cable allowable current values ​​of all the cables to obtain a total current value; taking the product of the aggregate current value and the three-phase unbalance correction coefficient as a first current value; The product of the charging current value set by the user and the three-phase unbalance correction coefficient is used as the second current value; The minimum value between the first current value and the second current value is used as a reference current value, and the product of the reference current value and the safety factor is set as the total allowable current value of the cable.

6. The method for controlling the power of a charger for construction machinery according to claim 1, characterized in that: Also includes: Obtain the remaining battery power from the battery management system; Obtaining a load current value of the load motor from the motor controller; The bus voltage of the motor controller is drooped according to the remaining battery power and the load current value.

7. The method for controlling the power of a charger for construction machinery according to claim 1, characterized in that: Also includes: Determining the 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 so, controlling the charger to supply power to the load motor and controlling the power battery pack to not supply power; If not, the charger and the power battery pack are controlled to jointly supply power to the load motor.

8. A charger power control system for engineering machinery, characterized in that: A vehicle controller for construction machinery, the construction machinery also including a power battery pack, a motor controller, and a load motor; when a charger plug is connected to the construction machinery, the power battery pack and the motor controller are respectively connected to the charger via a DC bus, and the charger is connected to a three-phase AC power supply via N cables. The charger power control system for the construction machinery includes: a parameter determination module, configured to determine hardware parameters of the charger; wherein the hardware parameters include the number of times each plug has been plugged in and out and status information of each cable; the status information includes current temperature, number of overtemperatures, and three-phase current values; the number of overtemperatures is the number of times the cable temperature exceeds a temperature threshold; A coefficient calculation module, configured to calculate the temperature attenuation coefficient, aging coefficient, and three-phase unbalance correction coefficient of each of the cables according to the hardware parameters; a cable total allowable current value calculation module, configured to calculate the cable total allowable current value based on the temperature attenuation coefficient, the aging coefficient, and the three-phase unbalance correction coefficient; The power supply control module is used to control the charger to supply power to the engineering machinery according to the total allowable current value of the cable, so as to control the power of the charger.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein a computer program is stored in the memory, and when the processor calls the computer program in the memory, the steps of the charger power control method for engineering machinery as claimed in any one of claims 1 to 7 are implemented.

10. A storage medium, characterized in that: The storage medium stores computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the charger power control method for engineering machinery as claimed in any one of claims 1 to 7.

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