Energy recovery and distribution system for coupling regenerative braking of mine truck with auxiliary power source

Abstract

The application discloses a mine vehicle regenerative braking and auxiliary power source coupling energy recovery and distribution system, relates to the new energy vehicle mine vehicle energy management technical field, and through obtaining a slope section sequence, vehicle state and auxiliary load attribute, predicts a regenerative residual amount and constructs a target energy receiving window, controls the auxiliary power source to pre-supply energy to the movable time auxiliary load before entering the slope to form an energy receiving space; after entering the slope, based on the real-time bus voltage and the target energy receiving window, a nonlinear model prediction method is used to realize that the regenerative braking energy is preferentially distributed to the auxiliary power source, and is transferred to the power battery after reaching the upper limit; when the system absorption capacity is insufficient, the motor braking force is reduced and the mechanical braking force is compensated, and the movable time auxiliary load is triggered to be synchronously consumed; the application can effectively improve the energy recovery efficiency of the new energy vehicle under complex working conditions and guarantee the braking safety.

Description

Technical Field

[0001] This invention relates to the field of energy management technology for new energy vehicles and mining trucks, specifically to an energy recovery and distribution system that couples regenerative braking and auxiliary power sources in mining trucks. Background Technology

[0002] Before fully loaded new energy vehicles enter the pit in high-altitude open-pit mines, the power batteries are often in a state of high SOC and low temperature limited charging due to the previous operating conditions. When entering a long downhill slope with continuous short-wave undulations, the peak value of regenerative braking is not synchronized with the pulse energy consumption of auxiliary loads such as steering pump, air compressor and lifting insulation. Existing technologies mostly only perform real-time recharging or resistive dissipation, without pre-constructing an energy window based on the potential energy of the slope to be driven and the movable auxiliary loads before entering the slope. This results in a small amount of but high-frequency overvoltage shear regeneration and mechanical braking heat superposition, which can easily cause local thermal degradation of mining vehicles. Summary of the Invention

[0003] The purpose of this invention is to provide an energy recovery and distribution system that couples regenerative braking and auxiliary power source for mining trucks, in order to address the shortcomings of the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an energy recovery and distribution system coupling regenerative braking and auxiliary power source for mining trucks, comprising:

[0005] Parameter acquisition module: acquires the sequence of slope sections to be driven, vehicle mass, vehicle speed, power battery SOC and charging limit power, remaining energy capacity of auxiliary power source, and rigidity and time-shiftable properties of auxiliary load;

[0006] Recycling margin assessment module: Based on the slope sequence, vehicle mass and speed, predict the recyclable potential energy of each slope segment, and determine the recycling margin in combination with the limited charging power;

[0007] Pre-scheduling control module: Determines the target energy receiving window for entering the slope based on the remaining amount of regeneration, the remaining energy receiving capacity and the movable time attributes, and controls the auxiliary power source to pre-supply energy to the movable auxiliary load before entering the slope, so as to form the target energy receiving window;

[0008] Busbar energy coupling distribution module: After entering the slope, based on the real-time busbar voltage and the target energy receiving window, the regenerative braking energy is preferentially distributed to the auxiliary power source, and the time-shiftable auxiliary load matching the current regenerative power is triggered to synchronously absorb the energy.

[0009] Control module: After the auxiliary power source reaches the upper limit of the target energy window, it distributes the subsequent regenerative braking energy to the power battery;

[0010] Safety Coordination Module: When the remaining amount of regenerated energy is still greater than the total absorbable amount of the auxiliary power source and the power battery, the motor power is reduced and the mechanical braking force is compensated, and the energy recovery and braking coordination control command is output.

[0011] Preferably, the step of predicting the recoverable potential energy of each slope segment based on the slope sequence, vehicle mass, and vehicle speed includes:

[0012] Based on the changes in slope, length and elevation of each sub-slope in the sequence of slopes to be driven, and combined with the vehicle mass and current speed, a segmented gravitational potential energy release model is constructed.

[0013] Based on the segmented gravitational potential energy release model, the recoverable potential energy corresponding to each sub-slope is calculated by superimposing vehicle rolling resistance, air resistance, and electric drive system recovery efficiency.

[0014] Preferably, determining the remaining amount of regeneration in conjunction with the limited charging power includes: converting the recyclable potential energy of each sub-slope segment into a predicted regeneration power sequence for the corresponding sub-slope segment according to the predicted passage time, and forming an acceptable power sequence for the sub-slope segment based on the limited charging power of the power battery; comparing the predicted regeneration power sequence with the acceptable power sequence for the sub-slope segment segment by segment, and determining the energy exceeding the acceptable power sequence for the sub-slope segment as the remaining amount of regeneration.

[0015] Preferably, determining the target energy window for entering the slope based on the remaining regeneration amount, remaining energy receiving capacity, and movable time attributes includes:

[0016] Based on the temporal distribution and peak position of the remaining regenerated amount, an energy demand curve to be absorbed after entering the slope is generated; the energy receiving range that can be reserved for the auxiliary power source is determined according to the remaining energy receiving capacity, and the energy demand curve to be absorbed is mapped as the target energy receiving window for entering the slope.

[0017] Preferably, the time-transferable auxiliary loads are sorted according to the latest start time, the allowable running time, and the continuous power supply time in the time-transferable attributes to form a pre-power supply sequence corresponding to the target energy receiving window for the slope entry; the auxiliary power source is controlled to pre-supply energy to the corresponding time-transferable auxiliary loads before entering the slope according to the pre-power supply sequence, and after the pre-power supply is completed, the current energy storage state of the auxiliary power source is verified to be consistent with the target energy receiving window for the slope entry.

[0018] Preferably, after entering the slope, the regenerative braking energy is preferentially allocated to the auxiliary power source based on the real-time bus voltage and the target energy receiving window, including:

[0019] Real-time bus voltage, current energy storage status of auxiliary power source, and target energy receiving window boundary are collected to construct a nonlinear prediction model with bus voltage deviation and auxiliary power source energy storage status deviation as state variables.

[0020] Based on the nonlinear prediction model, control barrier functions are constructed using the upper limit constraint of bus voltage and the boundary constraint of the target energy window, respectively. The control barrier functions are then embedded into the rolling optimization solution process to obtain the candidate power allocation sequence under the condition of preferential absorption by the auxiliary power source.

[0021] Based on the candidate power allocation sequence, the optimal allocation result that makes the bus voltage return to the target range and the energy storage state of the auxiliary power source remain within the target energy window is selected, and the regenerative braking energy is controlled to be preferentially allocated to the auxiliary power source.

[0022] When the current energy storage state of the auxiliary power source approaches the upper boundary of the target energy window, the power distribution of the auxiliary power source is reduced, and the remaining regenerative braking energy is switched to the power battery or mechanical braking.

[0023] Preferably, the total regenerative braking power Prec and the power that the power battery can currently accept Pbatacc are calculated at the current moment, and the regenerative braking energy distribution relationship is constructed. Specifically, when Prec≤Pbatacc, all regenerative braking power is allocated to the power battery, and the power battery undertakes all energy absorption tasks; when Prec>Pbatacc, the power corresponding to Pbatacc is allocated to the power battery.

[0024] Preferably, the braking coordination control commands include: motor regenerative braking power commands, mechanical braking pressure commands, and power battery charging power commands.

[0025] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0026] 1. This invention addresses the problem of inefficient utilization of regenerative braking energy in mining vehicles operating under high-slope, long-downhill conditions. It constructs an energy pre-scheduling mechanism based on a target energy window and a dynamic allocation strategy after entering the slope, prioritizing the allocation of regenerative braking energy to the auxiliary power source and then orderly transferring it to the power battery or other energy consumption pathways once the auxiliary power source reaches its energy limit. Compared to existing technologies that rely primarily on the power battery or use simple voltage limiting control, this invention, by introducing regenerative capacity prediction, energy window construction, and a rolling optimization allocation method constrained by a control barrier function, significantly reduces the risk of DC bus overvoltage, decreases the frequency of braking resistor participation, and improves the energy recovery rate of new energy vehicles in complex mining conditions.

[0027] 2. This invention achieves a unified optimization of braking safety and energy utilization efficiency by implementing coordinated control of electric motor power and mechanical braking force when regenerative energy cannot be fully absorbed, combined with a strategy for synchronous absorption of movable auxiliary loads. While ensuring the continuity and stability of the vehicle's braking response, it effectively avoids the charging limitations faced by new energy vehicles under high charge and low temperature conditions, reduces the thermal load and wear of mechanical braking, thereby extending the service life of key components and improving the reliability and economy of the entire vehicle. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0029] Figure 1 This is a flowchart of the system modules of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0031] For examples, please refer to Figure 1 As shown, the energy recovery and distribution system for the mining truck's regenerative braking and auxiliary power source coupling described in this embodiment includes:

[0032] Parameter acquisition module: This module acquires the sequence of slope sections to be traversed, vehicle mass, vehicle speed, SOC and limited charging power of the power battery, remaining energy capacity of the auxiliary power source, and rigid and time-shiftable attributes of the auxiliary load. In this embodiment, the parameter acquisition module is used to acquire multi-source operating parameters required for energy recovery and distribution in real time and accurately before the mining truck enters a long downhill working condition and during its journey, in order to support the prediction of potential energy and the construction of the energy receiving window for subsequent slope sections. This module is deployed in the vehicle controller (VCU) and interacts with the navigation system, battery management system (BMS), auxiliary power source controller, and various sensors through the vehicle communication bus (preferably CAN bus or Ethernet bus). For example, in a high-altitude open-pit copper mine application scenario, the fully loaded electric dump truck has a mass of 90t, and the typical entry condition is a continuous downhill section of about 3.2km in length, with an average slope of 8% and a local slope of up to 12%. The parameter acquisition module first obtains the sequence of slope segments to be driven through the vehicle-mounted high-precision positioning unit (GNSS) and electronic map. This sequence of slope segments includes multiple discrete sub-slope segments, each of which contains at least information on slope length, slope gradient, and elevation changes. For example, the 3.2km slope segment is divided into 32 sub-slope segments, each 100m long, and each sub-slope segment records the corresponding slope value (such as 8.5%, 9.2%, 11.8%, etc.).

[0033] Meanwhile, the parameter acquisition module obtains the vehicle mass through onboard weighing sensors or a mass estimation algorithm based on suspension pressure. In this embodiment, the axle loads are obtained by pressure sensors located on the axles, and the current vehicle mass is calculated to be 88t by combining the vehicle calibration parameters. The vehicle speed is obtained by converting wheel speed sensors or motor speed; for example, the initial speed entering the slope is 35km / h.

[0034] For the state parameters of the power battery, the parameter acquisition module obtains the state of charge (SOC) and charging limit power of the power battery through the battery management system (BMS). The SOC is calculated using a fusion algorithm of coulomb integral and open-circuit voltage, for example, the current SOC is 92%. The charging limit power is dynamically calculated by the BMS based on the battery temperature, SOC, and health status, for example, the charging limit power is 120kW under ambient temperature of -15℃.

[0035] For the remaining energy capacity of the auxiliary power source, the parameter acquisition module obtains its current status information through the auxiliary power source controller. In this embodiment, the auxiliary power source is a supercapacitor with a rated capacity of 5MJ and a current energy storage of 3.5MJ, so the remaining energy capacity is 1.5MJ. It can also be constrained by its maximum charging power limit (e.g., 300kW). For auxiliary load attributes, the parameter acquisition module classifies and identifies the vehicle auxiliary systems. Rigid attribute auxiliary loads are loads that must be powered in real time and cannot be scheduled, such as steering hydraulic pumps (approximately 15kW) and brake air compressors (approximately 20kW); time-delay attribute auxiliary loads are loads that can operate earlier or later within a certain time window, such as cargo compartment insulation and heating systems (approximately 25kW) and hydraulic lifting preheating systems (approximately 18kW). The parameter acquisition module identifies the above load attributes through the load controller or historical operating strategies and establishes a corresponding load list and its power requirement range. In addition, to ensure the real-time performance and consistency of the data, the parameter acquisition module refreshes the above parameters at a period of no more than 100ms and filters abnormal data, such as using moving average or Kalman filtering methods to smooth the vehicle speed and gradient data.

[0036] Through the above method, the parameter acquisition module can form a complete set of input parameters, including: slope sequence {Li,gi}, vehicle mass m, vehicle speed v, battery SOC and limited charging power Pbatlim, auxiliary power source remaining energy capacity Eauxrem, and auxiliary load attribute set {Loadrigid,Loadshift}, thus providing a sufficient and accurate data foundation for slope potential energy prediction and regeneration surplus calculation in subsequent steps. Loadrigid (rigid load set): represents the set of auxiliary loads that must be powered in real time during vehicle operation and cannot be delayed or scheduled. These loads have a direct impact on vehicle safety and basic functions, and their power requirements are mandatory and continuous. Typical examples include steering hydraulic pumps, brake air compressors, and power supply to the basic control system. For each load in Loadrigid, its power requirement must be prioritized at any given time and cannot participate in energy scheduling optimization or time shifting. Loadshift (time-shiftable load set): represents the set of auxiliary loads that can be operated earlier or later within a certain time window, provided that functional constraints are met. These types of loads typically have thermal inertia or mission tolerance time, such as cargo compartment insulation and heating systems, hydraulic system preheating devices, and non-critical cooling cycles. Loadshift allows loads to be started, stopped, or have their power adjusted based on the availability of regenerative braking energy, thereby enabling proactive absorption and optimized utilization of regenerative energy.

[0037] Recycling margin assessment module: Based on the slope sequence, vehicle mass and speed, predict the recyclable potential energy of each slope segment, and determine the recycling margin in combination with the limited charging power.

[0038] In this embodiment, before the mining truck enters a long downhill slope, it first segments the sequence of slope sections to be traveled based on the slope, elevation, and distance information corresponding to the route to be traveled. The sequence of slope sections to be traveled is derived from the matching information between the onboard electronic map and the positioning results, reflecting the longitudinal undulations of the continuous road segments after the vehicle's current position. To make the subsequent prediction results closer to actual working conditions, the sequence of slope sections to be traveled is divided into multiple contiguous sub-slopes. Each sub-slope records its slope length, slope, and elevation change. Preferably, the length of a single sub-slope is 50 meters; when the slope change within the same sub-slope exceeds 1.5 percentage points, it is further subdivided until the slope change within that sub-slope meets the stability requirements. This processing avoids masking local slope abrupt changes due to excessively large spans of single sub-slopes, thereby improving the resolution of recoverable potential energy prediction.

[0039] Based on the changes in slope, length and elevation of each sub-slope in the sequence of slopes to be driven, and combined with the vehicle mass and current speed, a segmented gravitational potential energy release model is constructed.

[0040] In this embodiment, the segmented gravitational potential energy release model is used to describe the theoretical gravitational potential energy that may be released when a mining truck descends along different sub-slopes due to the decrease in the vehicle's center of gravity height. Specifically, for each sub-slope, the elevation change of that sub-slope is first determined based on the slope length and gradient. If a sub-slope is downhill, then there is a positive elevation decrease in that sub-slope; if a sub-slope is flat or uphill, then no recoverable gravitational potential energy is generated in that sub-slope, and the elevation change of that sub-slope is treated as 0.

[0041] After determining the elevation change, the vehicle mass, gravitational acceleration, and elevation change of the sub-slope segment are multiplied to obtain the theoretical gravitational potential energy release for that sub-slope segment. This means that, under ideal conditions where rolling resistance, air resistance, and transmission losses are not considered, the vehicle releases all gravitational potential energy due to the decrease in altitude as it travels from the start to the end of the sub-slope segment. The gravitational acceleration is taken as 9.8 m / s². The theoretical gravitational potential energy release of the i-th sub-slope segment can be expressed as: ΔEg,i = m × 9.8 × Hi; where m represents the vehicle mass, and Hi represents the elevation change of the i-th sub-slope segment.

[0042] Furthermore, while the current vehicle speed does not directly participate in the numerical calculation of the theoretical gravitational potential energy release, it determines the vehicle's motion state when entering the first sub-slope and affects the travel time and resistance of each sub-slope. Therefore, it is retained as an initial boundary condition in the segmented gravitational potential energy release model. The entry speed of the first sub-slope is taken as the current vehicle speed; for the second and subsequent sub-slopes, the entry speed is taken as the exit speed of the previous sub-slope. This seamless connection ensures the continuity of the prediction process for the entire sequence of slopes to be traversed.

[0043] Based on the segmented gravitational potential energy release model, the recoverable potential energy corresponding to each sub-slope segment is calculated by superimposing vehicle rolling resistance, air resistance, and electric drive recovery efficiency.

[0044] In this embodiment, not all theoretical gravitational potential energy release can be converted into regenerative braking energy. During vehicle operation, it needs to overcome rolling resistance between the tires and the ground, as well as air resistance generated by the vehicle's high-speed movement. Furthermore, the electric drive system experiences energy conversion losses while generating electricity. Therefore, when calculating the recoverable potential energy for each sub-slope, the resistance loss should be deducted from the theoretical gravitational potential energy release, and then multiplied by the electric drive recovery efficiency.

[0045] First, the energy consumed by rolling resistance is determined by the following factors: the greater the vehicle mass, the greater the normal force between the tire and the ground, and the greater the rolling resistance; the gentler the slope, the closer the normal component is to the vehicle's weight, and the closer the rolling resistance is to a level road surface; the longer the sub-slope, the longer the rolling resistance lasts, and the more energy is consumed. In this embodiment, the rolling resistance coefficient is taken as 0.018. The rolling resistance energy consumption of the i-th sub-slope can be understood as "the product of the rolling resistance magnitude and the travel distance within the length of the sub-slope".

[0046] Secondly, the energy consumed by air resistance is closely related to vehicle speed. The higher the vehicle speed, the greater the air resistance, and the air resistance increases non-linearly with increasing vehicle speed. In this embodiment, the air resistance is determined by air density, drag coefficient, frontal area, and vehicle speed at the entrance of the sub-slope. Specifically, the air density is taken as 0.95 kg / m³, the drag coefficient as 0.85, and the frontal area as 9.5 m². The air resistance energy consumption of the i-th sub-slope can be understood as the product of the air resistance magnitude and the length of the sub-slope.

[0047] After obtaining the energy consumption from rolling resistance and air resistance, the two are added together to form the total resistance energy consumption of the i-th sub-slope segment. Then, the theoretical convertible mechanical energy of the sub-slope segment is obtained by subtracting the total resistance energy consumption from the theoretical gravitational potential energy release of that sub-slope segment. If the calculated result is less than 0, it indicates that the gravitational potential energy released by that sub-slope segment is insufficient to offset the vehicle's driving resistance; in this case, the recoverable potential energy of that sub-slope segment is recorded as 0, rather than taking a negative value.

[0048] Based on this, the electric drive recovery efficiency is then considered. The electric drive recovery efficiency characterizes the ability of the drive motor, inverter, and transmission components to convert mechanical energy into electrical energy under regenerative braking conditions. In this embodiment, the electric drive recovery efficiency is not set as a fixed constant, but is defined in segments according to the vehicle speed range: when the vehicle speed is less than 20 km / h, the electric drive recovery efficiency is 0.72; when the vehicle speed is between 20 km / h and 35 km / h, the electric drive recovery efficiency is 0.81; and when the vehicle speed is greater than 35 km / h, the electric drive recovery efficiency is 0.78. This setting aims to reflect the difference in energy conversion capability of the mining truck within different power generation speed ranges. The recoverable potential energy of the i-th sub-slope segment can be expressed as: Where ΔEloss,i represents the total resistance energy consumed by the i-th subslope segment, ηrec,i represents the electric drive recovery efficiency corresponding to the i-th subslope segment, and the max function represents taking the larger value between 0 and the result in parentheses.

[0049] The recyclable potential energy of each sub-slope is converted into a predicted regeneration power sequence for the corresponding sub-slope based on the predicted passage time, and a sub-slope acceptable power sequence is formed based on the power battery charging limit power.

[0050] In this embodiment, recyclable potential energy is the total amount expressed in the form of energy. Whether a residual amount of regeneration will be generated subsequently depends on whether the regenerative braking power generated per unit time exceeds the capacity of the power battery within the same time period. Therefore, it is necessary to convert the recyclable potential energy of each sub-slope section into a power value corresponding to time.

[0051] Specifically, the predicted travel time for each sub-slope segment is first calculated. The predicted travel time is determined by the length of the sub-slope segment and the average vehicle speed of that sub-slope segment. A higher average vehicle speed results in a shorter time for vehicles to pass through the sub-slope segment; under the condition of a fixed recoverable potential energy, the predicted regenerative power generated per unit time is higher. The entrance speed of the first sub-slope segment is the current vehicle speed; the entrance speed of the remaining sub-slope segments is the exit speed of the previous sub-slope segment. The exit speed can be recursively corrected based on the gradient changes and resistance differences between the preceding and following sub-slope segments. In engineering implementation, the arithmetic mean of the entrance speed and the exit speed can also be used as the average speed of that sub-slope segment. The predicted regenerative power of the i-th sub-slope segment is defined as the recoverable potential energy of that sub-slope segment divided by the predicted travel time of that sub-slope segment, i.e.: Where ti represents the predicted passage time of the i-th sub-slope segment.

[0052] The predicted regenerative power of all sub-slopes is arranged according to the actual driving sequence of the vehicle to form a predicted regenerative power sequence. This sequence reflects the possible trend of regenerative braking power changes at various spatial locations during the subsequent continuous downhill process.

[0053] Subsequently, a sequence of acceptable power for each sub-slope is formed based on the battery's limited charging power. This limited charging power, output by the battery management unit, represents the maximum charging power the battery is allowed to receive under safety constraints. The limited charging power is affected by the battery's state of charge, temperature, and health status. In this embodiment, to reduce misjudgments caused by instantaneous fluctuations in the limited charging power, the arithmetic mean of the limited charging power over three consecutive sampling times is taken as the current effective limited charging power. Then, this effective limited charging power is mapped to the corresponding sub-slope according to the predicted passage time for each sub-slope, forming a sequence of acceptable power for each sub-slope.

[0054] Furthermore, in high-altitude and cold mining conditions, if the battery temperature is below -15 degrees Celsius and the battery state of charge is above 90%, the battery is considered to be in a restricted charging state due to the combined effects of high state of charge and low temperature. In this case, the acceptable power of the corresponding sub-slope segment is corrected to 0.6 times the original effective limited charging power. This correction factor is used to reflect the reality that the charging acceptance capacity of the battery is significantly reduced under the combined effects of low temperature and high state of charge.

[0055] The predicted regeneration power sequence is compared segment by segment with the sub-slope section's acceptable power sequence to determine the energy exceeding the sub-slope section's acceptable power sequence as the regeneration surplus.

[0056] In this embodiment, each sub-slope segment is compared separately. If the predicted regenerative power of a sub-slope segment is less than or equal to the acceptable power of that sub-slope segment, it means that the power battery can absorb all the regenerative braking energy within that sub-slope segment, and no regenerative surplus is generated in that sub-slope segment. If the predicted regenerative power of a sub-slope segment is greater than the acceptable power of that sub-slope segment, the excess portion cannot be absorbed by the power battery in time, and this excess portion forms the regenerative surplus of that sub-slope segment within the corresponding travel time. In other words, the regenerative surplus of the i-th sub-slope segment is equal to the product of "the difference between the predicted regenerative power and the acceptable power of the sub-slope segment" and "the predicted travel time of the sub-slope segment". When explicit expression is required, it can be represented as: ; ;

[0057] Where Pacc,i represents the acceptable power of the i-th sub-slope segment, ΔPex,i represents the power excess of the i-th sub-slope segment, and ΔEex,i represents the regeneration surplus of the i-th sub-slope segment.

[0058] The regenerative residual amounts of all sub-slopes are summed to obtain the total regenerative residual amount corresponding to the sequence of slopes to be driven. The total regenerative residual amount is used to characterize the total scale of regenerative braking energy that the power battery cannot independently absorb during the current downhill task. If the total regenerative residual amount is greater than 0, it means that subsequent energy absorption space needs to be reserved through an auxiliary power source and synchronously absorbed with a portable load; if the total regenerative residual amount is equal to 0, it means that the power battery has the ability to absorb energy independently.

[0059] To avoid unnecessary scheduling actions caused by short-term, minor fluctuations, this embodiment also sets a regeneration surplus trigger threshold. The regeneration surplus trigger threshold is defined as 0.15 MJ. When the total regeneration surplus is not less than 0.15 MJ, a clear energy scheduling demand is determined; when the total regeneration surplus is less than 0.15 MJ, the deviation is determined to be insufficient to affect subsequent control decisions, and the auxiliary power source energy receiving window pre-construction action is not triggered.

[0060] The pre-scheduling control module determines the target energy receiving window for entering the slope based on the remaining regenerative capacity, remaining energy receiving capacity, and movable time attributes. It then controls the auxiliary power source to pre-supply energy to the movable time auxiliary load before entering the slope, thus forming the target energy receiving window. In this embodiment, the purpose of the pre-scheduling control module is not to passively allocate energy after regenerative braking occurs, but rather to pre-construct a capacity range for the auxiliary power source to receive regenerative braking energy based on the remaining regenerative capacity obtained in the previous steps before the mining truck enters the downhill section to be driven. Utilizing short periods of flat road, gentle slope, or low load conditions before entering the slope, the module controls the auxiliary power source to pre-supply energy to the movable time auxiliary load, allowing the auxiliary power source to release some of its existing stored energy, thereby forming a target energy receiving window at the start of the slope entry that matches the subsequent remaining regenerative capacity. The key technical point of this approach is that it does not directly increase the capacity of the auxiliary power source, but rather, based on the predicted results of the sequence of slope sections to be driven, it first determines the energy receiving space that needs to be freed up in the future, and then uses the movable time auxiliary load as the energy transfer object, completing the artificial relocation before entering the slope, thereby improving the absorption capacity of subsequent regenerative braking energy.

[0061] Based on the temporal distribution and peak position of the remaining regenerated amount, an energy demand curve to be absorbed after entering the slope is generated.

[0062] In this embodiment, the preceding steps have already obtained the regenerative capacity of each sub-slope segment. Since the regenerative capacity of each sub-slope segment appears segment by segment as the vehicle moves along the sequence of slope segments to be traveled, it naturally has a temporal order. In order to determine how much energy receiving space the auxiliary power source should reserve and when to prioritize accepting regenerative energy, it is necessary to first unfold the regenerative capacity of each sub-slope segment along the travel time axis to construct an energy demand curve to be absorbed.

[0063] In practice, the predicted passage time of each sub-slope segment is arranged sequentially according to its order in the sequence of slope segments to be driven, and the regeneration surplus of the corresponding sub-slope segment is mapped to that time interval. If the predicted passage time of the first sub-slope segment is 4 seconds and the predicted passage time of the second sub-slope segment is 5 seconds, then the regeneration surplus corresponding to the first sub-slope segment is distributed in the time interval from 0 seconds to 4 seconds after entering the slope, and the regeneration surplus corresponding to the second sub-slope segment is distributed in the time interval from 4 seconds to 9 seconds, thus forming a continuous time coordinate.

[0064] To characterize the strength of the auxiliary power source's energy demand at any given time after entering the slope, this embodiment divides the remaining regenerative capacity of a single sub-slope segment by the predicted travel time for that sub-slope segment to obtain the power value to be absorbed for that sub-slope segment. Then, the power values ​​to be absorbed for all sub-slope segments are arranged chronologically to obtain the energy demand curve. The horizontal axis of the energy demand curve represents the cumulative time after entering the slope, and the vertical axis represents the power demand to be absorbed at that moment. The significance of this approach is that, due to the limitations of the auxiliary power source's charging power capacity when absorbing regenerative energy, knowing only the total remaining regenerative capacity is insufficient to complete the window design; it is also necessary to know the time of demand occurrence and the peak magnitude.

[0065] In this embodiment, the temporal distribution is defined as the arrangement of the remaining regeneration capacity of each sub-slope segment along the cumulative time axis after entering the slope. The peak position is defined as the time position with the highest power value in the energy demand curve to be absorbed. The peak position is used to indicate the moment of highest energy-receiving pressure during the subsequent regenerative braking process and is a key basis for determining the lower limit of the target energy-receiving window for entering the slope.

[0066] To suppress spikes caused by excessively short sub-slope segments or sudden changes in local slope, this embodiment smooths the energy demand curve to be absorbed. The smoothing process employs a weighted moving average algorithm with a length of 3. The implementation is as follows: for the power value corresponding to the current moment, the power values ​​of the current sub-slope segment, the previous sub-slope segment, and the next sub-slope segment are weighted and summed, with weights of 0.5, 0.25, and 0.25 respectively; when the current sub-slope segment is located at the beginning or end of the sequence, only the adjacent power values ​​are used and normalized proportionally. This algorithm reduces the interference of single-point mutations on window settings without changing the overall energy scale.

[0067] The remaining energy receiving capacity determines the energy receiving range that the auxiliary power source can reserve, and the energy demand curve to be absorbed is mapped as the target energy receiving window for the slope.

[0068] In this embodiment, the auxiliary power source already has a certain energy storage level before entering the slope. Therefore, the space available for receiving regenerative braking energy is not the full rated capacity, but the remaining energy-receiving capacity. The remaining energy-receiving capacity is defined as the difference between the upper limit of the rated energy storage of the auxiliary power source and the current energy storage state of the auxiliary power source. Assuming the upper limit of the rated energy storage of the auxiliary power source is 5 MJ and the current energy storage state of the auxiliary power source is 3.6 MJ, then the remaining energy-receiving capacity is 1.4 MJ. However, the remaining energy-receiving capacity only represents the currently available spare capacity, and does not mean that it is all sufficient. If the total energy to be absorbed corresponding to the energy demand curve is greater than the remaining energy-receiving capacity, then it is necessary to further release some of the existing energy storage of the auxiliary power source before entering the slope to free up more space. To this end, this embodiment first constructs a reserved energy-receiving range for the auxiliary power source. The reserved energy-receiving range is defined as: the energy storage range that the auxiliary power source can additionally release through pre-supply before entering the slope, under the premise of not being lower than the lower limit of the safe energy storage of the auxiliary power source, and which is used to receive regenerative braking energy when entering the slope. The construction method is as follows:

[0069] First, a lower limit for the safe energy storage of the auxiliary power source is set. This lower limit is defined as the minimum energy storage value that the auxiliary power source must retain before the mining truck enters the downhill section, ensuring the energy supply needs of the basic auxiliary load under short-term abnormal conditions. In this embodiment, the lower limit is 20% of its rated upper limit. If the rated upper limit is 5 MJ, then the lower limit is 1 MJ. Second, the theoretically releaseable energy storage of the auxiliary power source is calculated. This theoretically releaseable energy storage is defined as the difference between the current energy storage state and the lower limit. If the current energy storage state is 3.6 MJ, then the theoretically releaseable energy storage is 2.6 MJ. Third, the theoretically releaseable energy storage is compared with the total energy to be absorbed corresponding to the energy demand curve, and the smaller value is taken as the pre-supply target release amount. This is because the purpose of releasing energy storage before entering the downhill section is only to create sufficient energy receiving space, not to completely deplete the auxiliary power source. If the total energy to be absorbed corresponds to 1.8 MJ of energy demand curve, then the target release amount of pre-supply energy is taken as 1.8 MJ; if the total energy to be absorbed is 3.4 MJ, then the target release amount of pre-supply energy is taken as 2.6 MJ.

[0070] Based on this, the target energy receiving window for downhill entry is defined as: the acceptable energy storage range that the auxiliary power source should reserve when the mining truck enters the downhill starting point, matching the energy demand curve to be absorbed. Specifically, the lower boundary of the target energy receiving window for downhill entry is the energy storage value after subtracting the pre-supply target release amount from the current energy storage state of the auxiliary power source; the upper boundary of the target energy receiving window for downhill entry is the rated energy storage limit of the auxiliary power source. In other words, the target energy receiving window for downhill entry corresponds to the energy storage space "from the target energy storage state before entering the downhill to the rated energy storage limit".

[0071] In addition to total energy matching, this embodiment also introduces peak power verification. If the peak power of the energy demand curve to be absorbed is greater than the allowable charging power of the auxiliary power source, then energy storage space alone is insufficient to guarantee the acceptance capacity during peak periods. Therefore, after determining the target energy receiving window, it is also necessary to verify whether the allowable charging power of the auxiliary power source is greater than or equal to 0.8 times the peak power. The 0.8 is the peak matching threshold, defined as the minimum acceptable power tracking ratio of the auxiliary power source for peak conditions. When the allowable charging power of the auxiliary power source is less than 0.8 times the peak power, the portion of the energy demand curve to be absorbed that exceeds the allowable charging power is marked as the power share that needs to be synchronously absorbed by subsequent portable auxiliary loads.

[0072] Based on the latest start time, advance running time, and continuous power supply duration in the time-shiftable attributes, the time-shiftable auxiliary loads are sorted to form a pre-power supply sequence corresponding to the target energy receiving window at the incline.

[0073] In this embodiment, releasing the auxiliary power source's stored energy before entering the slope is not a purposeless discharge, but rather a transfer of the stored energy to the movable auxiliary load, allowing the auxiliary energy that would otherwise be consumed at a later time to be executed ahead of schedule. Therefore, it is necessary to select loads suitable for operation before entering the slope from all movable auxiliary loads and arrange their execution in a certain order; this result is the pre-power supply sequence.

[0074] The time-shiftable attributes include the latest start time, the allowable start duration, and the continuous power supply duration. The latest start time is defined as the latest time the auxiliary load is allowed to start without affecting the achievement of its target function. The allowable start duration is defined as the maximum time the auxiliary load is allowed to be put into operation ahead of schedule, relative to the regular work plan. The continuous power supply duration is defined as the shortest continuous power supply duration required to complete the corresponding function after each start-up of the auxiliary load.

[0075] For example, the cargo compartment insulation and heating load can be heated before the vehicle arrives at the unloading area. If there are still 15 minutes before the unloading area, its latest start time can be set to 5 minutes before the unloading point, the allowable start time can be set to 10 minutes, and the continuous power supply time can be set to 4 minutes. The hydraulic lifting preheating load can start any 8 minutes before unloading, and its continuous power supply time can be set to 3 minutes. These parameters can quantify the time flexibility of different movable auxiliary loads.

[0076] The sorting process consists of three steps. Step 1: Remove movable auxiliary loads that do not meet the pre-entry execution conditions. If the latest start time of a movable auxiliary load is earlier than the current time, it means that the load has missed the opportunity to run early and is not included in the current sorting. Step 2: Calculate the pre-supply priority value for candidate movable auxiliary loads. The pre-supply priority value is defined as the weighted result of "transferable energy per unit continuous supply time" and "time urgency." The transferable energy per unit continuous supply time is equal to the product of the load's rated power and the continuous supply time; the time urgency is represented by the reciprocal of the remaining time from the current time to the latest start time; the shorter the remaining time, the higher the priority value. Step 3: Sort the loads according to their pre-supply priority values ​​from high to low, and accumulate the transferable energy of each load along the sorting results until the target pre-supply release amount is reached, thus obtaining the pre-supply sequence. To avoid frequent start-stop cycles, this embodiment stipulates that if a time-shiftable auxiliary load is included in the pre-power supply sequence, its continuous running time must not be less than the continuous power supply duration, and it is only allowed to be called once during a single ramp-up preparation process. This ensures that the sorting results can be directly used for subsequent execution. The output of step S330 is: the pre-power supply sequence arranged in the order of execution, and the start time and continuous power supply duration corresponding to each time-shiftable auxiliary load.

[0077] According to the pre-powered sequence, the auxiliary power source is controlled to pre-power the corresponding movable auxiliary load before entering the slope, and after the pre-powered sequence is completed, the current energy storage state of the auxiliary power source is verified to be consistent with the target energy window for entering the slope.

[0078] In this embodiment, the pre-power supply is scheduled based on the remaining time before the mine car reaches the downhill starting point. Specifically, the start time of each movable auxiliary load is determined first based on its ranking position, continuous power supply duration, and latest start time in the pre-power supply sequence. Upon start-up, the auxiliary power source supplies power to the movable auxiliary load via the corresponding power conversion interface, causing the auxiliary power source's current energy storage state to gradually decrease. After each pre-power supply action for a movable auxiliary load is completed, the current energy storage state of the auxiliary power source is read in real time and compared with the lower boundary of the target energy receiving window for the downhill slope. If the current energy storage state of the auxiliary power source is higher than the lower boundary of the target energy receiving window for the downhill slope, and there is still remaining time before the downhill starting point, the next movable auxiliary load in the pre-power supply sequence is executed. If the current energy storage state of the auxiliary power source has reached the lower boundary of the target energy receiving window for the downhill slope, subsequent pre-power supply actions are stopped, and no further loads are started, even if there are still unexecuted loads in the pre-power supply sequence, to prevent excessive decrease in the auxiliary power source's energy storage. If, after all pre-powered sequences have been completed, the current energy storage state of the auxiliary power source is still higher than the lower boundary of the target energy window for entering the slope, then a short-term power boost is allowed for the time-shiftable auxiliary loads with adjustable power in the sequence, with the boost duration limited to no more than the remaining preparation time for entering the slope.

[0079] The verification process includes numerical verification and boundary verification. Numerical verification is used to determine whether the current energy storage state of the auxiliary power source falls within the target energy receiving window for the slope; boundary verification is used to determine whether the current energy storage state is higher than the lower limit of the safe energy storage of the auxiliary power source. If the current energy storage state of the auxiliary power source is within the target energy receiving window for the slope and is higher than the lower limit of the safe energy storage of the auxiliary power source, then the target energy receiving window is considered to have been formed. If the current energy storage state of the auxiliary power source is lower than the lower boundary of the target energy receiving window for the slope, then all pre-power supply actions are stopped, and the current energy storage state is adjusted upward to the safe energy storage control value, which is 5% above the lower limit of the safe energy storage of the auxiliary power source. The purpose of setting this 5% upward adjustment is to reserve a buffer margin for the fluctuation of the rigid auxiliary load in the initial stage of the slope.

[0080] In a specific application scenario, the rated energy storage upper limit of the auxiliary power source is 5 MJ, the current energy storage state before entering the slope is 3.6 MJ, and the safe energy storage lower limit of the auxiliary power source is 1 MJ. Based on the energy demand curve, the total energy to be absorbed is 1.5 MJ, therefore the target pre-supply energy release is 1.5 MJ, corresponding to a lower boundary of the target energy receiving window for entering the slope of 2.1 MJ. Assume that among the movable auxiliary loads, the transferable energy of the cargo compartment insulation and heating load is 0.7 MJ, the transferable energy of the hydraulic lifting preheating load is 0.5 MJ, and the transferable energy of the non-critical cooling cycle load is 0.4 MJ. After prioritizing the pre-supply energy, the cargo compartment insulation and heating load, the hydraulic lifting preheating load, and the non-critical cooling cycle load are started sequentially. After the first two items are completed, the current energy storage state of the auxiliary power source drops to 2.4 MJ; after executing part of the third item, the current energy storage state of the auxiliary power source drops to 2.1 MJ, at which point the lower boundary of the target energy receiving window for entering the slope is reached, and additional pre-supply energy is stopped. When the vehicle enters a downhill section, the auxiliary power source has a capacity of 2.9 megajoules, which can be used to preferentially absorb subsequent regenerative braking energy.

[0081] Busbar energy coupling distribution module: After entering the slope, based on the real-time busbar voltage and the target energy receiving window, the regenerative braking energy is preferentially distributed to the auxiliary power source, and the time-shiftable auxiliary load matching the current regenerative power is triggered to synchronously absorb the energy.

[0082] Real-time bus voltage, current energy storage status of auxiliary power source, and target energy receiving window boundary are collected to construct a nonlinear prediction model with bus voltage deviation and auxiliary power source energy storage status deviation as state variables.

[0083] In this embodiment, the real-time bus voltage is acquired through a DC bus voltage sensor with a sampling period of 20 milliseconds; the current energy storage state of the auxiliary power source is calculated by integrating the voltage and current of the auxiliary power source; the target energy window boundary adopts the lower and upper boundaries determined in the previous steps. To facilitate subsequent optimization, the target bus voltage and the center value of the target energy window are defined first. The target bus voltage is defined as the rated operating voltage of the DC bus of the mining truck, which is 750 volts in this embodiment; the center value of the target energy window is defined as the arithmetic mean of the lower boundary and the upper boundary of the target energy window.

[0084] Based on this, the bus voltage deviation is defined as the difference between the real-time bus voltage and the target bus voltage; the auxiliary power source energy storage state deviation is defined as the difference between the current energy storage state of the auxiliary power source and the center value of the target energy receiving window. Using these two deviations as state variables can simultaneously reflect whether there is a risk of overshooting the real-time bus voltage, and whether the current energy storage state of the auxiliary power source deviates from the predetermined energy receiving range.

[0085] The nonlinear prediction model is constructed based on the DC bus power balance relationship and the energy storage change relationship of the auxiliary power source. In specific implementation, the regenerative braking power entering the DC bus at the current moment is first calculated, followed by the power absorbed by the auxiliary power source, the power absorbed by the power battery, the power absorbed by the portable auxiliary load, and the power converted into mechanical braking. The change in real-time bus voltage at the next sampling moment is determined by the difference between the regenerative braking power and the power to each destination mentioned above; the change in the current energy storage state of the auxiliary power source at the next sampling moment is determined by the product of the power allocated to the auxiliary power source and the sampling period. To reflect the nonlinear impact of power changes on the bus voltage, the DC bus capacitance and the auxiliary power source charging efficiency are introduced into the model, and the bus voltage change is calculated step-by-step using a discrete state update method.

[0086] In this embodiment, the prediction time domain length is 10 sampling periods, and the control time domain length is 5 sampling periods. For each prediction step, the prediction is recursively calculated in the order of "current state - input power - next state" to obtain the predicted values ​​of bus voltage deviation and auxiliary power source energy storage state deviation within the next 10 sampling periods. The output of this nonlinear prediction model serves as the basis for constructing the control barrier function and performing rolling optimization in step S420.

[0087] Based on the nonlinear prediction model, control barrier functions are constructed using the upper limit constraint of bus voltage and the boundary constraint of the target energy window, respectively. The control barrier functions are then embedded into the rolling optimization solution process to obtain the candidate power allocation sequence under the condition of preferential absorption by the auxiliary power source.

[0088] In this embodiment, the upper limit constraint on the bus voltage is used to prevent excessively rapid injection of regenerative braking energy from causing DC bus overvoltage. The upper limit of the bus voltage is defined as 780 volts. The closer the predicted real-time bus voltage is to this value, the more the auxiliary power source absorbs power or the portable auxiliary load synchronously absorbs power needs to be increased in subsequent sampling periods.

[0089] To address the upper limit constraint on the bus voltage, a first control barrier function is constructed. The value of the first control barrier function is defined as "the upper limit of the bus voltage minus the current predicted bus voltage". When the function value is greater than 0, it indicates that the predicted bus voltage is still within the allowable range; when the function value approaches 0, it indicates that the predicted bus voltage is approaching the upper limit; when the function value is less than 0, it indicates that the safety boundary has been exceeded. To ensure that the predicted trajectory always converges towards the safe region, a constraint is added during the rolling optimization solution process: the value of the first control barrier function in the next prediction step is not less than 0.8 times the value of the first control barrier function in the current prediction step. Here, 0.8 is defined as the control barrier function contraction coefficient, which limits the speed at which the predicted state approaches the boundary.

[0090] To constrain the target energy-receiving window boundary, a second and a third control barrier function are constructed. The value of the second control barrier function is defined as "the upper boundary of the target energy-receiving window minus the current energy storage state of the auxiliary power source"; the value of the third control barrier function is defined as "the current energy storage state of the auxiliary power source minus the lower boundary of the target energy-receiving window". The second control barrier function is used to restrict the current energy storage state of the auxiliary power source from exceeding the upper boundary of the target energy-receiving window; the third control barrier function is used to restrict the current energy storage state of the auxiliary power source from falling below the lower boundary of the target energy-receiving window. For both the second and third control barrier functions, the constraint "the function value of the next prediction step is not less than 0.8 times the function value of the current prediction step" is also added to ensure that the current energy storage state of the auxiliary power source always remains within the target energy-receiving window boundary.

[0091] Based on the above constraints, a rolling optimization solution process is constructed. The decision variables in the rolling optimization solution process include the power allocated to the auxiliary power source, the power allocated to the power battery, the power allocated to the portable auxiliary load for synchronous absorption, and the power converted into mechanical braking within several prediction steps. The objective function consists of three parts: the first part is the sum of squares of the bus voltage deviation, used to encourage the real-time bus voltage to return to the target bus voltage; the second part is the sum of squares of the auxiliary power source energy storage state deviation, used to ensure that the current energy storage state of the auxiliary power source remains near the center of the target energy window; the third part is the sum of squares of the power allocation change, used to suppress abrupt changes in power commands between adjacent sampling periods. To reflect the requirement of "prioritizing allocation to the auxiliary power source," a priority absorption weight of 1.5 is set for the power allocated to the auxiliary power source in the objective function; a secondary weight of 1.0 is set for the power allocated to the power battery; and a penalty weight of 3.0 is set for the power allocated to mechanical braking. Through this weighting relationship, the rolling optimization solution process prioritizes increasing the absorption ratio of the auxiliary power source while satisfying the control barrier function constraints.

[0092] The solution method employs a sequential quadratic programming algorithm. The specific steps are as follows: first, the power allocation result at the current sampling time is used as the initial solution; then, the nonlinear prediction model is linearized near the current operating point; next, the quadratic subproblem is solved under constraints; finally, the power allocation result is updated and the iteration is repeated until the change in the objective function between two adjacent iterations is less than 0.001. The solution yields a candidate power allocation sequence for the next five control steps. This candidate power allocation sequence serves as the input for selecting the optimal allocation result.

[0093] Based on the candidate power allocation sequence, the optimal allocation result that makes the bus voltage return to the target range and the energy storage state of the auxiliary power source remain within the target energy window is selected, and the regenerative braking energy is preferentially allocated to the auxiliary power source.

[0094] In this embodiment, the target bus range is defined as the range centered on the target bus voltage, offset by 10 volts above and below it, i.e., 740 volts to 760 volts. For each candidate power allocation sequence, the corresponding future bus voltage trajectory and auxiliary power source energy storage state trajectory are calculated one by one, and it is determined whether the following two conditions are met simultaneously: First, the bus voltage of each future prediction step does not exceed the upper limit of the bus voltage, and the bus voltage of the final prediction step enters the target bus range; Second, the auxiliary power source energy storage state of each future prediction step remains within the target energy receiving window boundary.

[0095] Among the candidate power allocation sequences that meet the above conditions, the following indicators are further compared: cumulative bus voltage deviation, cumulative auxiliary power source energy storage state deviation, cumulative mechanical braking power allocation, and cumulative power allocation to the power battery. A smaller cumulative bus voltage deviation indicates a more stable real-time bus voltage return; a smaller cumulative auxiliary power source energy storage state deviation indicates that the current energy storage state of the auxiliary power source is closer to the predetermined energy receiving location; a smaller cumulative mechanical braking power allocation indicates a higher regenerative braking energy utilization rate; and a smaller cumulative power allocation to the power battery indicates a higher degree of priority allocation to the auxiliary power source. Based on the principle of minimizing the weighted sum of these four indicators, the corresponding candidate power allocation sequence is selected as the optimal allocation result.

[0096] During control implementation, the entire optimal allocation result is not output all at once; instead, only the power command corresponding to the first control step in the optimal allocation result is output. After the current sampling period ends, the real-time bus voltage and the current energy storage status of the auxiliary power source are re-acquired, and the above steps are repeated. Through this cycle-by-cycle update method, the allocation result can be continuously corrected as the regenerative braking power fluctuates during downhill driving, ensuring that regenerative braking energy is consistently prioritized for allocation to the auxiliary power source.

[0097] When the current energy storage state of the auxiliary power source approaches the upper boundary of the target energy receiving window, the power allocated to the auxiliary power source is reduced, and the remaining regenerative braking energy is switched to the power battery or mechanical braking, triggering the synchronous absorption of a time-shiftable auxiliary load matching the current regenerative power. In this embodiment, "approaching the upper boundary of the target energy receiving window" needs to be clearly determined. The approach threshold is defined as 5% of the width of the target energy receiving window. If the current energy storage state of the auxiliary power source satisfies that "the upper boundary of the target energy receiving window minus the current energy storage state of the auxiliary power source" is less than or equal to 5% of the width of the target energy receiving window, then it is determined that the current energy storage state of the auxiliary power source is approaching the upper boundary of the target energy receiving window. Using this determination method, the power absorbed by the auxiliary power source can be reduced in advance before it actually reaches the upper boundary, avoiding exceeding the upper boundary of the target energy receiving window due to the instantaneous surge of regenerative braking power. After the approach condition is met, the remaining absorbable power of the auxiliary power source is calculated first. The remaining absorbable power of the auxiliary power source is defined as the maximum charging power allowed within the current sampling period so that the current energy storage state of the auxiliary power source does not exceed the upper boundary of the target energy receiving window. Then, the remaining absorbable power of the auxiliary power source is used as the new upper limit for the allocation of the auxiliary power source, and the power allocation of the auxiliary power source in the candidate power allocation sequence is readjusted. If the current regenerative braking power is greater than the readjusted power allocation of the auxiliary power source, the remaining portion forms the remaining regenerative braking energy.

[0098] For the remaining regenerative braking energy, the current acceptable power of the power battery is determined first. If the current acceptable power of the power battery is greater than or equal to the power corresponding to the remaining regenerative braking energy, then the remaining regenerative braking energy is switched to the power battery; if the current acceptable power of the power battery is less than that power, then a portion within the current acceptable power range of the power battery is first allocated to the power battery, and the remaining unaccepted portion is switched to mechanical braking. Through this sequence, it is ensured that mechanical braking only intervenes when neither the auxiliary power source nor the power battery can fully absorb the energy.

[0099] Simultaneously, the synchronous absorption of time-shifting auxiliary loads matching the current regenerative power is triggered. The "matching" is defined using a power matching error, which is the absolute value of the difference between the current additional power to be absorbed and the total power of the selected time-shifting auxiliary loads. The power matching error threshold is set at 10% of the current additional power to be absorbed. In practice, firstly, the rated power, shortest continuous power supply duration, and current startable flag of the time-shifting auxiliary loads in an operational state are read; then, they are sorted by rated power from smallest to largest; then, several time-shifting auxiliary loads are selected using a step-by-step aggregation method, ensuring that the total power of the selected time-shifting auxiliary loads is closest to the current additional power to be absorbed, and that the power matching error does not exceed the power matching error threshold. If multiple feasible combinations exist, the combination with the shortest continuous power supply duration is selected first to facilitate a rapid exit from the synchronous absorption state.

[0100] When the time-shiftable auxiliary load synchronous absorption is triggered, the selected time-shiftable auxiliary load will be put into operation according to its shortest continuous power supply duration. During operation, if the real-time bus voltage is still higher than the upper boundary of the target bus interval, synchronous absorption will continue; if the real-time bus voltage falls back to within the target bus interval, and the remaining regenerative braking energy corresponds to a power less than 50% of the total power of the selected time-shiftable auxiliary load, synchronous absorption will be exited after the minimum continuous power supply duration is met. Here, 50% is defined as the synchronous absorption exit threshold, used to avoid frequent start-stop of the time-shiftable auxiliary load.

[0101] By executing the above steps, after entering the slope, the real-time bus voltage can be used as the object of rapid adjustment, and the boundary of the target energy receiving window can be used as the state constraint boundary. Under the constraint of the control obstacle function, rolling optimization solution can be continuously executed to make the regenerative braking energy preferentially allocated to the auxiliary power source. When the current energy storage state of the auxiliary power source approaches the upper boundary of the target energy receiving window, the power battery, mechanical braking and movable auxiliary load are switched in sequence to absorb the energy synchronously. This achieves coordinated control of bus voltage stability, target energy receiving window maintenance and high proportion of regenerative braking energy utilization.

[0102] Control module: After the auxiliary power source reaches the upper limit of the target energy window, the subsequent regenerative braking energy is distributed to the power battery.

[0103] In this embodiment, when the mining truck is in a downhill regenerative braking condition, the regenerative braking energy is preferentially allocated to the auxiliary power source to improve energy recovery efficiency. When the current energy storage state of the auxiliary power source gradually increases and approaches the upper limit of the target energy receiving window, its energy receiving capacity needs to be limited, and the subsequent regenerative braking energy is reasonably transferred to the power battery.

[0104] First, a clear determination is made regarding whether the auxiliary power source has reached the upper limit of the target energy-receiving window. This determination is achieved using an upper limit approximation threshold method. Specifically, let the upper limit of the target energy-receiving window be Emax, and the current energy storage state of the auxiliary power source be Eaux. Then, the auxiliary power source is determined to have reached the upper limit of the target energy-receiving window when the following condition is met: Emax − Eaux ≤ ΔEth; where ΔEth is the upper limit approximation threshold, used to prevent the energy storage state of the auxiliary power source from exceeding the upper limit of the target energy-receiving window due to sampling delay or sudden changes in regeneration power. In this embodiment, ΔEth is taken as 5% of the target energy-receiving window width. The target energy-receiving window width is defined as the difference between the upper limit and the lower limit of the target energy-receiving window.

[0105] After determining that the auxiliary power source has reached the upper limit of the target energy window, the system enters the control phase for transferring regenerative braking energy to the power battery. At this time, the total regenerative braking power Prec is first calculated, which is determined by the output power of the drive motor in generator mode. Simultaneously, the current acceptable power of the power battery, Pbatacc, is obtained. This current acceptable power is calculated by the power battery management unit based on the power battery's state of charge, temperature, and safe charging constraints.

[0106] Subsequently, the regenerative braking energy distribution relationship is constructed. Specifically:

[0107] When Prec≤Pbatacc, all regenerative braking power is allocated to the power battery, at which point the power battery undertakes all energy absorption tasks.

[0108] When Prec > Pbatacc, the power corresponding to Pbatacc is allocated to the power battery, and the remaining part is defined as the residual regenerative braking power Pexcess, where: Pexcess = Prec − Pbatacc; the above residual regenerative braking power needs to be further processed to avoid the DC bus voltage rising beyond the safe range.

[0109] To ensure the smoothness of the energy distribution process, a power change rate constraint is introduced in this embodiment. The power change rate constraint is defined as follows: the change in power allocated to the power battery within two adjacent sampling periods must not exceed a preset change rate threshold ΔPrate. This threshold is used to suppress sudden changes in the charging power of the power battery and avoid impacting the battery. In this embodiment, ΔPrate is taken as 10% of the rated charging power of the power battery.

[0110] During execution, a cycle-by-cycle update method is adopted. Within each sampling cycle, the following steps are performed:

[0111] The first step is to collect the current regenerative braking power Prec and the current acceptable power Pbatacc of the power battery;

[0112] The second step is to calculate the target power allocation for the power battery in this cycle according to the above allocation rules.

[0113] The third step is to apply a power change rate constraint to the target allocated power to obtain the actual allocated power;

[0114] The fourth step is to send the actual allocated power as a control command to the power battery charging control interface.

[0115] Furthermore, to prevent charging limitations of the power battery under high state of charge or low temperature conditions, this embodiment sets dynamic correction conditions for the current acceptable power of the power battery. When the power battery's state of charge is greater than 90% and the power battery temperature is below -10 degrees Celsius, the current acceptable power of the power battery is corrected to 0.5 times the original value. This correction factor is used to reflect the decrease in the power battery's charging capacity under extreme operating conditions.

[0116] Using the above method, after the auxiliary power source reaches the upper limit of the target energy window, subsequent regenerative braking energy can be transferred to the power battery in an orderly manner, and the utilization rate of regenerative braking energy can be maximized while meeting the power battery charging constraints. Simultaneously, the continuity and safety of the entire energy distribution process are ensured through power change rate constraints and dynamic correction mechanisms.

[0117] When the power battery cannot fully absorb the remaining regenerative braking power, it can be further allocated to mechanical braking or triggered by a movable auxiliary load to absorb it synchronously in order to maintain the stability of the DC bus voltage.

[0118] Safety Coordination Module: When the remaining amount of regenerated energy is still greater than the total absorbable amount of the auxiliary power source and the power battery, the motor power is reduced and the mechanical braking force is compensated, and the energy recovery and braking coordination control command is output.

[0119] In this embodiment, when the mining truck is in a downhill regenerative braking condition, regenerative braking energy is preferentially absorbed through the auxiliary power source and the power battery. However, under certain extreme conditions, such as high charge state, low temperature environment, and continuous steep slope conditions, the regenerative braking power may exceed the total absorption capacity of the auxiliary power source and the power battery, resulting in a regenerative surplus. In this case, it is necessary to coordinate motor braking and mechanical braking to achieve a balance between the vehicle's braking demand and energy recovery capacity.

[0120] First, a determination is made regarding whether the remaining regenerative capacity is still greater than the total absorbable capacity of the auxiliary power source and the power battery. Let the current regenerative braking power be Prec, the absorbable power of the auxiliary power source be Pauxacc, and the absorbable power of the power battery be Pbatacc. Then, the total absorbable power is defined as: Ptotalacc = Pauxacc + Pbatacc. A remaining regenerative capacity is determined to exist when the following condition is met: Prec > Ptotalacc. Further, the excess is defined as the remaining regenerative braking power Pexcess: Pexcess = Prec − Ptotalacc. This remaining regenerative braking power represents the energy that the current system cannot absorb through the electrical energy path and needs to be addressed by adjusting the braking distribution strategy.

[0121] After determining that there is residual regenerative braking power, the system enters the stage of reducing electric motor braking force and compensating for mechanical braking force. First, the target total braking force is determined based on the current vehicle braking demand. The target total braking force is determined by the driver's brake pedal opening or the automatic driving control command, and is converted into an equivalent braking force demand value Freq through a braking calibration curve.

[0122] Secondly, the electric braking force and mechanical braking force are decoupled and distributed. The equivalent braking force corresponding to the electric braking force is denoted as Fmot, which has a corresponding relationship with the regenerative braking power; the equivalent braking force corresponding to the mechanical braking force is denoted as Fmech.

[0123] In this embodiment, the reduction in motor power is determined based on the remaining regenerative braking power. Specifically, the maximum allowable power corresponding to the current motor power is calculated to ensure it does not exceed the total absorbable power. Then, the power corresponding to the motor power is reduced from Prec to Ptotalacc, and the corresponding motor power is adjusted from Fmot to Fmotnew.

[0124] To ensure that the total braking demand remains constant, the mechanical braking force needs to be compensated. The compensation amount for the mechanical braking force is defined as: ΔFmech = Fmot − Fmotnew; the compensated mechanical braking force is: Fmechnew = Fmech + ΔFmech.

[0125] Through the above treatment, the braking force reduced by the decrease in electric motor power is completely made up by mechanical braking force, thereby ensuring that the total braking force of the vehicle meets Freq.

[0126] In the specific implementation, to avoid vehicle stability issues caused by sudden changes in braking force, a rate of change constraint is set for both the electric motor braking force and the mechanical braking force. The rate of change constraint is defined as follows: the change in electric motor braking force within adjacent sampling periods must not exceed 15% of its current value, and the change in mechanical braking force must not exceed 20% of its current value. This constraint ensures a smooth transition in the braking distribution process. Furthermore, to prevent frequent triggering of electric motor braking force reduction, this embodiment sets a regenerative capacity trigger threshold Pth. When Pexcess is greater than or equal to Pth, electric motor braking force reduction is executed; when Pexcess is less than Pth, the current braking distribution remains unchanged. In this embodiment, Pth is set to 50 kilowatts to filter out the impact of short-term, small fluctuations.

[0127] After distributing the electric motor's power and mechanical braking force, a coordinated control command for energy recovery and braking is generated. This control command includes: a motor regenerative braking power command, a mechanical braking pressure command, and a power battery charging power command. This control command is updated once per sampling cycle and sent to the corresponding execution unit, thereby achieving coordinated control of regenerative braking and mechanical braking.

[0128] By using the above method, when the regenerated residual amount exceeds the system's absorption capacity, the electric motor's power can be reduced in a timely manner and the mechanical braking force can be compensated. Under the premise of ensuring braking safety, DC bus overvoltage can be avoided, while taking into account both energy recovery efficiency and vehicle stability.

[0129] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. An energy recovery and distribution system coupling regenerative braking and auxiliary power source for mining trucks, characterized in that: include: Parameter acquisition module: acquires the sequence of slope sections to be driven, vehicle mass, vehicle speed, power battery SOC and charging limit power, remaining energy capacity of auxiliary power source, and rigidity and time-shiftable properties of auxiliary load; Recycling margin assessment module: Based on the slope sequence, vehicle mass and speed, predict the recyclable potential energy of each slope segment, and determine the recycling margin in combination with the limited charging power; The pre-scheduling control module determines the target energy receiving window for entering the slope based on the remaining regeneration capacity, remaining energy receiving capacity, and movable time attributes, and controls the auxiliary power source to pre-supply energy to the movable auxiliary load before entering the slope to form the target energy receiving window, including: Based on the temporal distribution and peak position of the remaining regenerated amount, an energy demand curve to be absorbed after entering the slope is generated; the energy receiving range that the auxiliary power source can reserve is determined according to the remaining energy receiving capacity, and the energy demand curve to be absorbed is mapped as the target energy receiving window for entering the slope; Busbar energy coupling and distribution module: After entering the slope, based on the real-time busbar voltage and the target energy receiving window, the regenerative braking energy is preferentially distributed to the auxiliary power source, and a time-shiftable auxiliary load matching the current regenerative power is triggered to synchronously absorb the energy, including: Real-time bus voltage, current energy storage status of auxiliary power source, and target energy receiving window boundary are collected to construct a nonlinear prediction model with bus voltage deviation and auxiliary power source energy storage status deviation as state variables. Based on the nonlinear prediction model, control barrier functions are constructed using the upper limit constraint of bus voltage and the boundary constraint of the target energy window, respectively. The control barrier functions are then embedded into the rolling optimization solution process to obtain the candidate power allocation sequence under the condition of preferential absorption by the auxiliary power source. Based on the candidate power allocation sequence, the optimal allocation result that makes the bus voltage return to the target range and the energy storage state of the auxiliary power source remain within the target energy window is selected, and the regenerative braking energy is controlled to be preferentially allocated to the auxiliary power source. When the current energy storage state of the auxiliary power source approaches the upper boundary of the target energy window, the power distribution of the auxiliary power source is reduced, and the remaining regenerative braking energy is switched to the power battery or mechanical braking. Control module: After the auxiliary power source reaches the upper limit of the target energy window, it distributes the subsequent regenerative braking energy to the power battery; Safety Coordination Module: When the remaining amount of regenerated energy is still greater than the total absorbable amount of the auxiliary power source and the power battery, the motor power is reduced and the mechanical braking force is compensated, and the energy recovery and braking coordination control command is output.

2. The energy recovery and distribution system for mining trucks coupled with regenerative braking and auxiliary power source according to claim 1, characterized in that: The method of predicting the recoverable potential energy of each slope segment based on the slope sequence, vehicle mass, and vehicle speed includes: Based on the changes in slope, length and elevation of each sub-slope in the sequence of slopes to be driven, and combined with the vehicle mass and current speed, a segmented gravitational potential energy release model is constructed. Based on the segmented gravitational potential energy release model, the recoverable potential energy corresponding to each sub-slope is calculated by superimposing vehicle rolling resistance, air resistance, and electric drive system recovery efficiency.

3. The energy recovery and distribution system for mining trucks coupled with regenerative braking and auxiliary power source according to claim 2, characterized in that: Determining the remaining amount of regeneration based on the limited charging power includes: converting the recoverable potential energy of each sub-slope segment into a predicted regeneration power sequence for the corresponding sub-slope segment according to the predicted passage time, and forming an acceptable power sequence for the sub-slope segment based on the limited charging power of the power battery; comparing the predicted regeneration power sequence with the acceptable power sequence for the sub-slope segment segment by segment, and determining the energy exceeding the acceptable power sequence for the sub-slope segment as the remaining amount of regeneration.

4. The energy recovery and distribution system for mining trucks coupled with regenerative braking and auxiliary power source according to claim 1, characterized in that: Based on the latest start time, advance running time, and continuous power supply duration in the movable time attributes, the movable time auxiliary loads are sorted to form a pre-power supply sequence corresponding to the target energy receiving window for the slope entry; the auxiliary power source is controlled to pre-supply energy to the corresponding movable time auxiliary loads before entering the slope according to the pre-power supply sequence, and after the pre-power supply is completed, the current energy storage state of the auxiliary power source is verified to be consistent with the target energy receiving window for the slope entry.

5. The energy recovery and distribution system for mining trucks coupled with regenerative braking and auxiliary power source according to claim 1, characterized in that: Calculate the total regenerative braking power Prec and the current acceptable power Pbatacc of the power battery at the current moment, and construct the regenerative braking energy distribution relationship. Specifically, when Prec≤Pbatacc, all regenerative braking power is allocated to the power battery, and the power battery undertakes all energy absorption tasks. When Prec>Pbatacc, the power corresponding to Pbatacc is allocated to the power battery.

6. The energy recovery and distribution system for mining trucks coupled with regenerative braking and auxiliary power source according to claim 1, characterized in that: The braking coordination control commands include: motor regenerative braking power command, mechanical braking pressure command, and power battery charging power command.

Images