An energy management method for a new energy three-electric system of an engineering vehicle

Abstract

The application discloses an energy management method for a new energy three-electricity system of an engineering vehicle, and relates to the technical field of new energy three-electricity systems.The method comprises the following steps: S100, analyzing the driving requirements of the engineering vehicle; S200, intelligently deciding the power; and S300, executing in real time based on feedforward.The application constructs a three-layer closed-loop control architecture of accurate requirement perception, intelligent power decision and safe feedforward execution, and constructs an energy management method with intelligent decision capability and strong execution force.The method not only eliminates the risk of engine stalling due to the superposition of electric-hydraulic load from the root by feedforward constraint based on real-time hydraulic power, but also realizes intelligent scheduling and fine management of battery and fuel energy by means of fixed electric quantity following and regenerative braking recovery strategy.Meanwhile, the safety execution is ensured by battery power boundary protection and anti-integration fan mechanism, so as to comprehensively guarantee the stability and service life of the three-electricity system.

Description

Technical Field

[0001] This invention relates to the field of new energy electric drive technology, and in particular to an energy management method for a new energy electric drive system for engineering vehicles. Background Technology

[0002] With the global energy structure adjustment and increasingly stringent environmental regulations, new energy technologies have become the core direction for the transformation and upgrading of the construction machinery industry. As key equipment for infrastructure construction and industrial production, construction vehicles are undergoing a profound transformation in their power systems, shifting from traditional internal combustion engines to new energy three-electric systems. The three-electric systems of new energy construction vehicles—the power battery system, drive motor system, and power generation / distribution control system—constitute the core of the vehicle's energy storage, conversion, and distribution. The performance of these three systems directly determines the operating efficiency, economy, and reliability of new energy construction vehicles, and is a key technology for whether new energy construction vehicles can successfully replace traditional construction vehicles and achieve green development.

[0003] However, the unique operating characteristics of new energy engineering vehicles pose significant challenges to the energy management of their electric drive systems. Unlike new energy passenger vehicles, which experience relatively stable driving conditions, new energy engineering vehicles are characterized by frequent load fluctuations, a high proportion of hydraulic power, and complex and diverse operating modes. One of the biggest risks of new energy engineering vehicles is that the engine may slow down or stall due to a sudden increase in instantaneous load (i.e., engine stalling), which can lead to work interruptions, equipment damage, and safety accidents. Therefore, existing energy management strategies for new energy engineering vehicles are mostly geared towards stable operating conditions or optimizing the driving experience, lacking effective feedforward control and safety redundancy for the hydraulic coupling load and the engine's instantaneous capacity constraints. Summary of the Invention

[0004] Therefore, it is necessary to provide an energy management method for the three-electric system of new energy engineering vehicles to address the problems mentioned in the background technology above.

[0005] The objective of this invention can be achieved through the following technical solution: an energy management method for the three-electric system of a new energy engineering vehicle, comprising the following steps:

[0006] Step S100: Based on the vehicle sensor signals and the pre-calibrated drive motor external characteristic MAP and regenerative braking strategy MAP, the total vehicle power demand, including drive request power, regenerative braking power and accessory power, is obtained by analysis; wherein the vehicle sensor signals include accelerator pedal opening, brake pedal opening, vehicle speed and gear position.

[0007] Step S200 runs in discrete cycles to obtain the battery status, and uses mode decision, battery power boundary protection and anti-integral wind to perform chain processing on the total vehicle demand power obtained in step S100 to generate discrete final execution power.

[0008] In step S300, the power of the hydraulic system is estimated in real time in the continuous time domain. The safe power generation boundary is calculated based on the engine's maximum capacity and the preset safety margin to obtain the safe power. The discrete final execution power in step S200 is then subjected to feedforward constraints to obtain the continuous power generation command and continuous torque command sent to the motor for execution.

[0009] In some embodiments, step S100 specifically includes:

[0010] By consulting the MAP diagram of the external characteristics of the drive motor based on the accelerator pedal opening and vehicle speed, the torque T(t) and speed r(t) of the motor in drive mode are obtained. The drive power request P is then calculated based on the drive motor efficiency. drv (t), the calculation formula is: ;in, The driving efficiency of the motor in drive mode represents the instantaneous mechanical energy conversion efficiency of the motor at the current moment, defined as the ratio of the motor's output mechanical power to its input power; 0 < ≤1;

[0011] When the conditions for regenerative braking are met, i.e., brake pedal opening Brake(t) > 0, accelerator pedal opening Accel(t) = 0, and vehicle speed V(t) is greater than a preset vehicle speed threshold, the regenerative braking torque Tregen(t) is obtained by using the brake pedal opening Brake(t) and vehicle speed V(t) through a pre-calibrated regenerative braking strategy MAP.

[0012] ;

[0013] Next, the regenerative braking power P is calculated. reg (t), the calculation formula is:

[0014] ,

[0015] in, The instantaneous mechanical energy to electrical energy conversion efficiency of the motor at time t under regenerative braking conditions is defined as the ratio of the electrical power output by the motor to the DC bus to the mechanical power absorbed by the motor from the wheels. If the braking energy recovery condition is not met, the regenerative braking power P... reg (t) = 0;

[0016] The total power required by the vehicle is obtained by summing the drive power request, regenerative braking power, and accessory power; where accessory power represents the total power consumption of accessories required to maintain the operation of other vehicle functions, excluding the drive motor and regenerative braking system.

[0017] In some embodiments, the rule for pattern decision-making in step S200 is:

[0018] The target operating range of the battery's state of charge (SOC) is preset, and the strategic power generation is set.

[0019] If the battery's state of charge (SOC) is lower than the lower threshold of the target operating range, the system enters charging mode. The strategy's power generation is equal to the sum of the vehicle's total power demand and a set charging power, calculated as follows:

[0020] ,

[0021] Among them, P gen target (k) represents the power generation of the strategy: P total (k) represents the total power required by the entire vehicle; P setpoint (k) is the target charging power set based on the desired charging rate of the battery's state of charge (SOC) difference, as detailed below:

[0022] ,

[0023] in, This is an engineering calibration factor used to map the difference in battery state of charge (SOC) to a charging power target.

[0024] If the battery's state of charge (SOC) is higher than the upper limit threshold of the target operating range, the system enters pure electric mode, and the strategy power generation is zero, i.e., the strategy power generation P... gen target (k): ;

[0025] If the battery's state of charge (SOC) is within the target operating range, it enters power follower mode. The strategy power generation is the sum of the total power demand of the vehicle and the output power of the PI controller, i.e., the strategy power generation P. gen target (k): ,in This is the initial power generation target.

[0026] In some embodiments, the battery power boundary protection in step S200 specifically includes:

[0027] Calculate the theoretical power demand of the battery, which is the difference between the total power demand of the vehicle and the power generation strategy under the current mode; use the real-time maximum charge and discharge power provided by the battery management system in the vehicle to saturate and limit the theoretical power demand of the battery. The expression for the saturation limit is:

[0028] ,

[0029] Where Pmax is the maximum charging power of the battery, Pdismax is the maximum discharging power of the battery, and P batt req (k) represents the theoretical power requirement of the battery;

[0030] Under saturation constraints, if the theoretical power demand of the battery is not equal to the power values ​​before and after, the power generation of the strategy is corrected by back calculation to obtain the final execution power, so as to determine the saturation constraint of the theoretical power demand of the battery; if no saturation constraint occurs, the final execution power is equal to the power generation of the strategy.

[0031] In some embodiments, the process of resisting integral wind in step S200 is as follows:

[0032] The saturation deviation Δu(k) is obtained by subtracting the strategy power generation from the final executed power obtained from the battery power boundary protection. The integrator value I(k+1) for the next cycle is calculated using an integral update formula with a write-back term.

[0033] ,

[0034] Where I(k) is the integration term, i.e., the current value of the integrator; Ki is the integration gain; e SOC (k) represents the error of the battery's state of charge (SOC); Ts is the control period; K aw k is the write-back coefficient; k is the discrete time index, indicating the discrete time number corresponding to the current control cycle when step S200 is run in discrete cycle; k+1 is the discrete time number corresponding to the next control cycle.

[0035] Then, the final execution power is output after each update step.

[0036] In some embodiments, step S300 specifically includes:

[0037] Real-time acquisition of hydraulic flow and main hydraulic pressure of the hydraulic system, calculation of instantaneous power consumption of the hydraulic system, i.e., hydraulic power P. hyd (t), the calculation formula is:

[0038] ,

[0039] Where Q(t) is the hydraulic flow rate; p hyd (t) represents the hydraulic main pressure;

[0040] Obtain the engine's maximum usable power at the current speed, and subtract the hydraulic power and accessory power to obtain the engine's remaining power generation capacity, denoted as P. avail (t);

[0041] Subtracting a preset engine power safety margin from the remaining generating capacity yields the continuous safe power boundary available for power generation, i.e., the safe power, denoted as P. safe (t);

[0042] The aforementioned engine power safety margin is denoted as P. engine (t);

[0043] By using continuous safe power to perform real-time feedforward constraints on the discrete final execution power in step S200, the final continuous power generation command sent to the generator for execution is obtained.

[0044] The continuous torque command required by the motor at the current generator speed is calculated based on the continuous power output command.

[0045] In some embodiments, the real-time feedforward constraint is achieved by taking the minimum value between the final executed power and the safe power as the final continuous power generation command sent to the generator for execution.

[0046] In some embodiments, the calculation process of the continuous torque command is as follows:

[0047] The continuous torque command required by the motor at the real-time generator speed is calculated based on the continuous power output command. The calculation formula is as follows:

[0048] Among them, P gen cmd (t) represents the continuous power generation command; r(t) represents the real-time motor speed; T gen cmd (t) indicates a continuous torque command.

[0049] In some embodiments, after executing the final continuous power generation command and continuous torque command, the actual output power of the motor is fed back to step S200 for the calculation of the theoretical battery power demand at the next discrete time k+1 and the update of the integrator value I(k+1), thereby forming a closed-loop control.

[0050] Compared with the prior art, the beneficial effects of the present invention are:

[0051] 1. By integrating the MAP diagram of the external characteristics of the drive motor with the MAP diagram of the regenerative braking strategy, the total power demand of the vehicle is obtained. This allows for the analysis of power demand, enabling accurate interpretation of the driver's intentions. Furthermore, the regenerative braking energy is incorporated into the total demand framework, providing accurate demand input for subsequent energy allocation and improving energy utilization efficiency from the source.

[0052] 2. By interleaving the total power demand of the vehicle through mode decision-making, battery boundary protection, and anti-integral wind, discrete final execution power is obtained. This constructs an intelligent decision-making system that takes into account both economic goals and physical constraints. It not only uses a fixed power following strategy to maintain battery health, but also ensures the executability of instructions through battery power saturation back-calculation. Furthermore, it effectively suppresses integral saturation with a write-back correction mechanism, ensuring the stability and rapid recovery capability of the system under boundary conditions, and realizing the robustness of the strategy.

[0053] 3. By estimating hydraulic power in real time and calculating the engine's remaining power generation capacity, combined with a preset safety margin, feedforward hard constraints are applied to the upper-level power generation command to obtain continuous power generation command and continuous torque command. This fundamentally eliminates the risk of engine overload shutdown (stalling) caused by the superposition of electro-hydraulic loads, ensuring the continuity and reliability of engineering vehicles under extreme and sudden load conditions. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a schematic diagram of the principle of the present invention. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Application Scenarios: In practical applications, unlike passenger vehicles with relatively stable driving conditions, engineering vehicles are characterized by frequent load changes, high hydraulic power ratios, and complex and diverse operating modes. One of the biggest risks of engineering vehicles is that the engine may slow down or stall due to a sudden increase in instantaneous load (i.e., engine stalling), which can lead to work interruption, equipment damage, and safety accidents. Existing vehicle energy management strategies are mostly aimed at stable operating conditions or optimizing the driving experience, lacking effective feedforward control and safety redundancy for the hydraulic coupling load and the engine's instantaneous capacity constraints of engineering vehicles. To solve this technical problem, this invention takes a range-extended electric loader as an example and applies the energy management method of this invention. The power system consists of an engine-generator set as the core power generation and drive unit. Specifically, the engine output shaft is coaxial with the motor rotor or rigidly connected through a transmission mechanism. The engine does not directly drive the vehicle; its function is to provide mechanical energy to the motor to drive its power generation, or to provide auxiliary power to the motor in a specific mode. The motor, as a power conversion device with dual functions of driving and power generation, is mechanically coupled to the engine. Its working mode is switched according to the needs of the entire vehicle: the engine and the motor together constitute an engine-generator set, forming an integrated power and energy conversion unit. The energy management method of the present invention, based on this hardware configuration, performs coordinated management and optimization of the engine output, the motor operating mode and power, and the power battery energy.

[0058] This invention constructs a three-layer closed-loop control architecture encompassing precise demand perception, intelligent power decision-making, and safe feedforward execution. This architecture enables an energy management system that combines intelligent decision-making capabilities with robust execution. It not only eliminates the risk of engine stalling due to electro-hydraulic load superposition by using feedforward constraints based on real-time hydraulic power, but also achieves intelligent scheduling and refined management of battery and fuel energy through fixed power following and regenerative braking recovery strategies. Simultaneously, it ensures safe execution through battery power boundary protection and an anti-integral wind mechanism, thereby comprehensively guaranteeing the stability and service life of the three-electric system.

[0059] Example

[0060] like Figure 1 As shown, an energy management method for the three-electric system of a new energy engineering vehicle includes the following steps:

[0061] Step S100: Accelerator pedal opening (Accel(t), brake pedal opening (Brake(t), vehicle speed V(t), and gear position) are acquired in real time via the vehicle's CAN bus. Based on this, the power demand of the engineering vehicle is analyzed to obtain the total power demand P of the entire vehicle. total (t); t represents continuous time, indicating the actual physical time during the operation of the engineering vehicle; in practical applications, gears include forward, neutral, and reverse; the specific requirements analysis process is as follows:

[0062] S101, Obtain the MAP diagram of the external characteristics of the drive motor of the engineering vehicle, and map the accelerator pedal opening and vehicle speed according to the MAP diagram to obtain the torque T(t) and speed r(t) of the motor in the current driving mode requested by the driver: In practical applications, the drive motor external characteristic MAP (Motor External Characteristic Map) is the final performance representation resulting from the coupled effects of three major technical fields: electromagnetic design, thermal management, and power electronic control. It serves as the fundamental basis for the vehicle controller to perform power distribution, torque limiting, and efficiency optimization. The drive motor external characteristic MAP is a two-dimensional color contour plot with motor speed as the horizontal axis and motor torque as the vertical axis, clearly depicting the boundaries of the maximum torque and power that the motor can safely and continuously output throughout its entire operating range (from standstill to maximum speed). The requested drive power P is calculated based on the torque T(t) and speed R(t) of the motor in the current drive mode requested by the driver. drv (t), the calculation formula is: ,in The driving efficiency of the motor in drive mode represents the instantaneous mechanical energy conversion efficiency of the motor at the current moment, defined as the ratio of the motor's output mechanical power to its input electrical power; 0 < ≤1;

[0063] S102, extract the brake pedal opening Brake(t). If the brake pedal opening Brake(t) > 0, the accelerator pedal opening Accel(t) = 0, and the vehicle speed V(t) is greater than the preset vehicle speed threshold, then brake energy recovery is determined. The regenerative braking torque Tregen(t) is obtained by using the brake pedal opening Brake(t) and vehicle speed V(t) through the pre-calibrated regenerative braking strategy MAP. Next, the regenerative braking power P is calculated. reg (t), the calculation formula is: ,in The instantaneous mechanical energy to electrical energy conversion efficiency of the motor at time t under regenerative braking conditions is defined as the ratio of the electrical power output by the motor to the DC bus to the mechanical power absorbed by the motor from the wheels; otherwise, the regenerative braking power P reg (t) = 0; Specifically, the regenerative braking strategy MAP is a pre-calibrated data table or graph. Based on the real-time vehicle speed and brake pedal opening as input conditions, it can quickly query the regenerative braking torque corresponding to achieving the best energy recovery efficiency and ensuring braking safety and comfort under the current working conditions.

[0064] S103, estimate the total power consumption of accessories required to maintain the operation of other vehicle functions, excluding the electric motor drive mode and regenerative braking system, and obtain the accessory power P. aux (t); In practical applications, the accessory power Paux (t) includes the constant power consumption of low-pressure accessories such as air conditioning, steering pump, and fan on the vehicle. During the vehicle design phase, the steady-state power consumption of key low-pressure accessories such as air conditioning compressor, steering pump, and cooling fan under typical operating conditions (such as rated speed and maximum load) is measured by bench testing and used as accessory power P. aux (t); Total power demand of the vehicle P total (t) equals the sum of the drive request power, regenerative braking power, and accessory power: P total (t) = Pdrv (t) + P reg (t) + P aux (t), representing the total power demand P of the entire vehicle. total (t) is passed to step S200;

[0065] By integrating the external characteristics map of the drive motor and the regenerative braking strategy map, the total power demand of the vehicle is obtained. This allows for the analysis of power demand, enabling accurate interpretation of the driver's intentions. Furthermore, the regenerative braking energy is incorporated into the total demand framework, providing accurate demand input for subsequent energy allocation and improving energy utilization efficiency from the source.

[0066] Step S200: The battery state of charge (SOC(t), maximum charging power Pmax, and maximum discharging power Pdismax) of the engineering vehicle's power battery management system (BMS) are acquired in real-time via the CAN bus. Based on this, a power balance analysis is performed to generate the final execution power. Saturation and inverse calculations are performed within the battery's capacity range to ensure that the SOC remains within the preset target operating range [SOCmin, SOCmax], while considering the coordination of battery and engine constraints. It should be noted that in this step, the variable is represented by discrete time k, and the mapping relationship between continuous time t and discrete time k is as follows: Where Ts is the slow update cycle of the EMS, i.e., the PI controller update cycle; the specific process is as follows:

[0067] S201, mapping continuous time t to discrete time k for sampling. The target operating range for the preset battery state of charge (SOC) is denoted as [SOCmin, SOCmax]. The battery charge error value e is obtained by subtracting the real-time battery state of charge from the SOC reference value. SOC (k): e SOC (k) = SOCref - SOC(k); Calculate the unsaturated PI command u cmd (k): Where I(k) is the current integrator value; the unsaturated PI output is combined with the power following baseline to form the initial power generation target. : Initial power generation target It is the fundamental target in power follower mode and serves as the benchmark for subsequent PI correction;

[0068] S202, if the battery state of charge (SOC(k)) is less than the lower limit SOCmin of the target operating range, then enter the charging mode, requiring power generation to meet and prioritize replenishing battery energy, and set the strategy power generation P. gen target (k): ;P setpoint (k) is the target charging power set based on the SOC gap and the desired charging speed. ,in This is an engineering calibration coefficient used to map the SOC difference to a charging power target. If the battery's state of charge (SOC) (k) is greater than the upper limit of the target operating range (SOCmax), then the system enters pure electric mode, prioritizing battery consumption, and sets the strategy power generation P. gen target (k): If the battery's state of charge (SOC(k)) is within the target operating range, it enters power follower mode, prioritizing battery consumption and setting the strategy to generate power P. gen target (k): ;

[0069] S203, subtract the initial power generation target from the total power demand of the vehicle at discrete time k to obtain the theoretical power demand P of the battery. batt req (k): The theoretical power requirement of the battery is saturated, and the saturation expression is: ; This represents the theoretical power demand of the battery after saturation; if the theoretical power demand of the battery is not equal before and after saturation, then... ≠ If saturation occurs, it is determined that the lower-level physical capabilities have limited the implementation of the ideal command. If saturation occurs, the final executable power generation target is calculated in reverse according to the following formula to meet the battery capacity, and the final executed power P is obtained. fin target (k): If saturation does not occur, the final execution power P gen target (k) equals the strategy power generation P gen target (k), that is ;

[0070] S204, to avoid the integrator continuously accumulating when the lower stage becomes saturated (integral wind), a write-back correction method is used to smoothly roll back the integral quantity. The specific process is as follows: the final execution power P is... gen target (k) Subtract the strategy power generation P gen target (k) yields the saturation deviation Δu(k), which reflects the amount of correction to the ideal power generation command due to battery capacity limitations;

[0071] Subsequently, the integrator value I(k+1) for the next period is calculated using the integral update formula with a write-back term: Where I(k) is the integral value at the current time, Ki is the integral gain, and K... aw The write-back coefficient is used to adjust the write-back speed of the integral term. This formula ensures that the saturation effect of the downstream actuator can be fed forward to the integrator. When saturation occurs (i.e., Δu(k) ≠ 0), the write-back term... This will generate a correction to the integrator proportional to the saturation deviation, bringing its value closer to the actual executable capability, thereby effectively avoiding integral saturation and overshoot during system recovery; the final execution power P will be output after each update step. fin target (k), and pass it to step S300;

[0072] By implementing a chain reaction of mode decision-making, battery boundary protection, and anti-integral wind to ultimately execute power, an intelligent decision-making system that balances economic goals and physical constraints is constructed. This system not only maintains battery health by using a fixed power following strategy, but also ensures the executability of instructions through battery power saturation back-calculation. Furthermore, a write-back correction mechanism effectively suppresses integral saturation, ensuring the system's stability and rapid recovery capability under boundary conditions, thus achieving the robustness of the strategy.

[0073] Step S300, under continuous time t, based on the final execution power P gen target (k) Calculate and execute the safety-constrained power generation command P in conjunction with real-time hydraulic and engine state constraints. gen cmd (t), while simultaneously outputting the actual power generation P act (t) is used for closed-loop correction to EMS; where P fin target (k) in It remains constant over time; the specific process is as follows:

[0074] S301, real-time monitoring and acquisition of hydraulic flow rate Q(t) and hydraulic main pressure p hyd (t), and calculate the hydraulic power P based on this. hyd (t), the calculation formula is: ; Real-time acquisition of the maximum available power at the current engine speed r(t), and subtraction of the hydraulic power P. hyd (t) and the engine accessory power are used to obtain the remaining power available for power generation after the engine has satisfied the hydraulic load and mechanical accessory consumption. This remaining power generation power is denoted as P. avail (t);

[0075] S302, the preset engine margin is denoted as P. engine(t), which is used to cope with instantaneous changes in hydraulic load, providing a power buffer for the engine and avoiding speed drop or stalling caused by instantaneous overload due to the superposition of power generation and hydraulic power; this value is determined by bench testing based on the engine's dynamic response characteristics and the maximum impact load of the hydraulic system; for the remaining power generation P avail (t) Deduct the engine reserve margin P engine (t) and ensure that the non-negative engine obtains a continuous safe power boundary that can be used for power generation, denoted as the safe power P. safe (t), that is: ; Utilizing continuous safe power P safe (t) for discrete final execution power P gen target (k) Perform real-time feedforward constraints to obtain the final continuous power generation command P issued to the motor for execution. gen cmd (t), Real-time feedforward constraint: at the final execution power P gen target (k) and safe power P safe The minimum value in (t) is taken. Even if the upper-level strategy wants to generate more power, as long as the engine's real-time remaining capacity is insufficient, the power generation command will be immediately limited to the safety boundary to avoid engine stalling from the source.

[0076] S303, based on continuous power generation command P gen cmd (t) Calculate the continuous torque command T required by the motor at the real-time motor speed r(t). gen cmd (t), the calculation formula is: and the continuous torque command T required by the motor gen cmd (t) The command is sent to the GCU (motor control unit) for execution. After the command is sent, the actual output power P of the motor is obtained through the sensor. act (t), after this continuous signal is sampled, it can be fed back to step S200 at discrete time k+1 to calculate the theoretical power requirement of the battery. The update of the integrator value I(k+1) forms a global closed-loop control.

[0077] By estimating hydraulic power in real time and calculating the engine's remaining power generation capacity, combined with a preset safety margin, feedforward hard constraints are applied to the upper-level power generation command to obtain continuous power generation command and continuous torque command. This fundamentally eliminates the risk of engine overload shutdown (stalling) caused by the superposition of electro-hydraulic loads, ensuring the continuity and reliability of engineering vehicles under extreme and sudden load conditions.

[0078] The core idea of ​​this invention is to construct a three-layer closed-loop control architecture, as detailed below:

[0079] Phase 1: Demand Perception

[0080] To accurately understand the driving needs of the vehicle, sensor signals are read in real time via the vehicle's CAN bus, including accelerator pedal opening, brake pedal opening, current vehicle speed, and gear information. Based on the current accelerator pedal opening and vehicle speed, the external characteristic map of the drive motor is consulted to obtain the torque and speed that the driver expects to output in the current motor drive mode. Then, combined with the drive efficiency of the motor in the drive mode, the drive request power that needs to be obtained from the electric system to meet this drive request is calculated. Based on the accelerator pedal opening, brake pedal opening, and current vehicle speed, it is determined whether the conditions for regenerative braking are met. If the conditions are met, the regenerative braking torque that should be generated is obtained based on the current brake pedal opening and vehicle speed. Next, combined with the efficiency of the motor in the generator state, the regenerative braking power that can be recovered and recharged back to the battery is calculated (this is a negative value, indicating the power charged to the system); if the energy recovery conditions are not met, the regenerative braking power is zero. Finally, the calculated drive request power, regenerative braking power, and the constant power consumed by low-pressure accessories such as the air conditioner and power steering pump are added together to obtain the total power demand of the entire vehicle at the current moment.

[0081] The goal of this stage is to avoid wasting any recoverable energy and to accurately translate the driver's intentions into specific power demands, providing a precise basis for subsequent energy allocation.

[0082] Phase Two: Intelligent Decision-Making

[0083] It intelligently allocates energy between the battery and the motor and makes decisions in a fixed control cycle. Under the premise of ensuring battery safety, it intelligently decides how much electricity the engine-generator set should generate. It monitors the remaining power of the power battery in real time and presets the target working range of the battery's state of charge (SOC). The two endpoints of this target working range are the set lower health limit (lower threshold) and upper health limit (upper threshold).

[0084] If the battery level falls below the set health threshold, the system enters charging mode. In this mode, the power output of the engine-generator set is not only required to meet the vehicle's overall driving needs, but also to provide additional power to charge the battery.

[0085] If the battery charge is higher than the set health limit, it enters pure electric mode. In this mode, the engine-generator set is not activated, and the battery supplies all the required power.

[0086] If the battery charge is within the target operating range, it enters power follow mode. In this mode, the power output of the engine-generator set generally follows the vehicle's total power demand; simultaneously, an intelligent controller fine-tunes the battery charge to keep it stable within the ideal range.

[0087] Then, based on the power generation strategy decided in the previous step, the power that the battery needs to bear or absorb is calculated, and the maximum charging power and maximum discharging power of the battery are obtained in real time from the battery management system. The calculated power demand of the battery is compared and limited with these two physical limits to ensure that it does not exceed the safe operating range of the battery.

[0088] If the calculated power exceeds the battery's limit, the power output of the engine-generator set is immediately reversed and corrected to ensure that the battery power does not exceed the limit from the source. When the battery boundary protection function is activated, the power output command is corrected and the correction amount, Δu(k), is calculated. Then, Δu(k) is used to reversely adjust an internal cumulative value of the intelligent controller to prevent the intelligent controller from continuously issuing commands that cannot be executed, ensuring stability under extreme conditions and a fast and smooth response when conditions recover, avoiding large fluctuations.

[0089] The goal at this stage is to maintain the battery level at a healthy state while ensuring that all commands are within the battery's physical capabilities.

[0090] Phase Three: Safe Execution

[0091] To robustly handle sudden load changes and prevent engine stalling; to operate continuously within the time domain, ensuring the safe execution of second-stage decision-making instructions, and most importantly, to prevent engine stalling due to sudden load increases (i.e., "engine stalling"); during engineering vehicle operation, the hydraulic system (such as bucket and boom movements) consumes a significant amount of energy and experiences drastic power fluctuations. Real-time reading of hydraulic oil flow and main pressure allows for instantaneous calculation of the hydraulic system's power consumption. Subtracting the calculated real-time hydraulic power from the engine's maximum capacity, and then subtracting the power consumed by the engine's own accessories, yields the remaining engine power available for power generation.

[0092] To cope with potential sudden impacts from hydraulic loads, a safety margin (as a buffer power value) is pre-deducted from the remaining power generation capacity, resulting in a continuously updated safe power generation boundary. The final execution power determined in the second stage is compared with the real-time calculated safe power generation boundary, and the smaller value is taken as the final command issued to the motor. This means that regardless of the required power output, if the motor's capacity is insufficient as detected in real time, the command will be immediately limited to within the safety limit, fundamentally eliminating the risk of stalling. Finally, this safe power generation command is converted into a specific torque command based on the motor's real-time speed and issued to the motor control unit for execution. The actual power output of the motor is measured by sensors and fed back to the intelligent decision-making layer in the second stage for calculation and correction in the next control cycle, forming a self-correcting and continuously optimizing closed-loop control system.

[0093] The goal of this phase is to ensure that the motor will not be overloaded at any time through real-time and forward-looking power constraints, thereby guaranteeing the continuity and reliability of engineering vehicles under extreme and sudden load conditions.

[0094] In summary, this invention achieves an energy management method that combines intelligent decision-making and robust execution through a closed-loop process of precise perception, intelligent decision-making, safe execution, and feedback optimization, thereby comprehensively improving the stability, economy, and service life of the three-electric systems in new energy engineering vehicles.

[0095] The above formulas are all derived from software simulation using a large amount of data, and are selected to be close to the actual values. The coefficients in the formulas are set by those skilled in the art based on the actual situation.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for energy management of the three-electric system (battery, motor, and electronic control system) of a new energy engineering vehicle, characterized in that, Includes the following steps: Step S100: Based on the vehicle sensor signals and the pre-calibrated drive motor external characteristic MAP and regenerative braking strategy MAP, the total vehicle power demand, including drive request power, regenerative braking power and accessory power, is obtained by analysis; wherein the vehicle sensor signals include accelerator pedal opening, brake pedal opening, vehicle speed and gear position. Step S200 runs in discrete cycles to obtain the battery status, and uses mode decision, battery power boundary protection and anti-integral wind to perform chain processing on the total vehicle demand power obtained in step S100 to generate discrete final execution power. Step S300 involves estimating the hydraulic system power in real time within the continuous time domain, calculating the safe power generation boundary based on the engine's maximum capacity and a preset safety margin, obtaining the safe power, and applying feedforward constraints to the discrete final execution power from step S200 to obtain the continuous power generation command and continuous torque command sent to the motor for execution; specifically including: Real-time acquisition of hydraulic flow and main hydraulic pressure of the hydraulic system, and calculation of instantaneous power consumption of the hydraulic system, i.e., hydraulic power; Obtain the engine's maximum available power at the current speed, and subtract the hydraulic power and accessory power to get the engine's remaining power generation capacity; Subtracting a preset engine power safety margin from the remaining power generation capacity yields the continuous safe power boundary that can be used for power generation, i.e., the safe power. By using continuous safe power to perform real-time feedforward constraints on the discrete final execution power in step S200, the final continuous power generation command sent to the motor for execution is obtained. The continuous torque command required by the motor at the current motor speed is calculated based on the continuous power generation command.

2. The energy management method for the three-electric system of a new energy engineering vehicle according to claim 1, characterized in that, Step S100 specifically includes: Based on the accelerator pedal opening and vehicle speed, the external characteristic MAP diagram of the drive motor is consulted to obtain the torque and speed of the motor in drive mode, and the drive request power is calculated by combining the drive efficiency of the motor in drive mode. When the conditions for regenerative braking are met, the regenerative braking torque is obtained by querying the regenerative braking strategy MAP based on the brake pedal opening and vehicle speed, and the regenerative braking power is calculated in combination with the regenerative efficiency. The total power required by the vehicle is obtained by summing the drive request power, regenerative braking power and accessory power; where accessory power represents the total power consumption of accessories required to maintain the operation of other vehicle functions, excluding the electric motor drive mode and regenerative braking system.

3. The energy management method for the three-electric system of a new energy engineering vehicle according to claim 2, characterized in that, In step S200, the rule for pattern decision-making is as follows: The target operating range of the battery's state of charge (SOC) is preset, and the strategic power generation is set. If the battery's state of charge (SOC) is lower than the lower threshold of the target operating range, it will enter charging mode, and the strategy's power generation will be equal to the sum of the total power demand of the vehicle and a set charging power. If the battery state of charge (SOC) is higher than the upper limit threshold of the target operating range, it enters pure electric mode and the strategy power generation is zero. If the battery's state of charge (SOC) is within the target operating range, it enters power follower mode, where the power generation is the sum of the total power demand of the vehicle and the output power of the PI controller.

4. The energy management method for a new energy vehicle's three-electric system according to claim 3, characterized in that, In step S200, the battery power boundary protection specifically includes: The theoretical power demand of the battery is calculated by the difference between the total power demand of the vehicle and the power generation of the strategy under the current mode; the theoretical power demand of the battery is saturated and limited by the real-time maximum charge and discharge power provided by the battery management system in the vehicle. Under saturation constraints, if the theoretical power demand of the battery is not equal before and after, the power generation of the strategy is corrected by back calculation to obtain the final execution power, so as to ensure that the theoretical power demand of the battery is saturated.

5. The energy management method for a new energy vehicle's three-electric system according to claim 4, characterized in that, In step S200, the process of resisting integral wind is as follows: The saturation deviation Δu(k) is obtained by subtracting the strategy power generation from the final executed power obtained from the battery power boundary protection. The integrator value I(k+1) for the next cycle is calculated using an integral update formula with a write-back term. ， wherein I(k) is an integral term, i.e. the current value of the integrator; Ki is an integral gain; e SOC (k) is an error of the battery state of charge SOC; Ts is a control period; K aw is a write-back coefficient; k is an index of discrete time, representing a sequence number of the discrete time corresponding to the current control period when the step S200 runs in discrete periods; k+1 is a sequence number of the discrete time corresponding to the next control period. Then, the final execution power is output after each update step.

6. The energy management method for the three-electric system of a new energy engineering vehicle according to claim 1, characterized in that, The real-time feedforward constraint is achieved by taking the minimum value between the final executed power and the safe power, which is then used as the final continuous power generation command sent to the motor for execution.

7. The energy management method for a new energy vehicle's three-electric system according to claim 6, characterized in that, The calculation process for the continuous torque command is as follows: The continuous torque command required by the motor at the real-time motor speed is calculated based on the continuous power generation command. The calculation formula is as follows: Among them, P gen cmd (t) represents the continuous power generation command; r(t) represents the real-time motor speed; T gen cmd (t) indicates a continuous torque command.

8. The energy management method for a new energy vehicle's three-electric system according to claim 5, characterized in that, Step S300 further includes: After executing the final continuous power generation command and continuous torque command, the actual output power of the motor is fed back to step S200 for the calculation of the theoretical battery power demand at the next discrete time k+1 and the update of the integrator value I(k+1), thereby forming a closed-loop control.

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