Electric tractor with power suspension and endurance control system and method

Abstract

The invention discloses an electric tractor with a power suspension and an endurance control system and method, and relates to the technical field of electric tractors, and the endurance control system comprises a data acquisition module used for acquiring target data; the control module is used for determining the distribution proportion of the driving torque of the tractor and the driving torque of the power trailer according to the driving torque required by the whole vehicle and the driving working condition of the whole vehicle when the ratio of the electric quantity of the power battery pack of the tractor to the electric quantity of the power battery pack of the power trailer is within a set proportion range; when the ratio is greater than the upper limit of the set proportion range, reducing the driving torque of the power trailer and increasing the driving torque of the tractor; when the ratio is smaller than the lower limit of the set proportion range, the driving torque of the power trailer is increased, and the driving torque of the tractor is reduced. The endurance mileage of the electric tractor is increased, and the power performance of the electric tractor is enhanced.

Description

Technical Field

[0001] The present application relates to the technical field of electric tractors, and particularly to an electric tractor with a powered trailer, a cruising range control system and a method therefor. Background Art

[0002] Currently, electric tractors are powered by their own battery packs. Since the installable power of the power battery is limited by the vehicle space layout and the battery capacity is limited, the cruising range is short, making it difficult to meet the requirements of medium- and long-distance trunk transportation. Frequent charging is required, resulting in low transportation efficiency. In addition, in the face of heavy loads, climbing slopes, accelerating, etc., relying on the electric tractor's own power system, there may be insufficient power output, resulting in slow vehicle speed, difficult climbing, and even affecting the completion of normal transportation tasks. Summary of the Invention

[0003] The purpose of the present application is to provide an electric tractor with a powered trailer, a cruising range control system and a method therefor, which not only increases the cruising range of the electric tractor but also enhances the power performance of the electric tractor.

[0004] To achieve the above object, the present application provides the following solutions:

[0005] In a first aspect, the present application provides a cruising range control system for an electric tractor with a powered trailer. The electric tractor with a powered trailer includes a tractor and a powered trailer, and the powered trailer is used to provide auxiliary power for the tractor. The cruising range control system for the electric tractor with a powered trailer includes:

[0006] A data acquisition module for acquiring target data; the target data includes the power of the tractor's power battery pack, the power of the powered trailer's power battery pack, the driving torque required by the whole vehicle, and the driving conditions of the whole vehicle; the whole vehicle includes the tractor and the powered trailer;

[0007] A control module for determining the distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer according to the driving conditions of the whole vehicle when the ratio of the power of the tractor's power battery pack to the power of the powered trailer's power battery pack is within a set ratio range, and determining the driving torque of the tractor and the driving torque of the powered trailer according to the distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer and the driving torque required by the whole vehicle; the lower limit of the set ratio range is less than 1; the upper limit of the set ratio range is greater than 1;

[0008] When the ratio of the power of the tractor's power battery pack to the power of the powered trailer's power battery pack is greater than the upper limit of the set ratio range, reduce the driving torque of the powered trailer and increase the driving torque of the tractor;

[0009] Moreover, when the ratio of the power battery pack power of the tractor to the power battery pack power of the powered trailer is less than the lower limit of the set ratio range, increase the driving torque of the powered trailer and decrease the driving torque of the tractor.

[0010] In a second aspect, the present application provides a cruising range control method for an electric tractor with a powered trailer. The electric tractor with a powered trailer includes a tractor and a powered trailer, and the powered trailer is used to provide auxiliary power for the tractor. The cruising range control method for the electric tractor with a powered trailer includes:

[0011] Obtain target data; the target data includes the power of the tractor power battery pack, the power of the powered trailer power battery pack, the driving torque required by the whole vehicle, and the driving conditions of the whole vehicle; the whole vehicle includes a tractor and a powered trailer;

[0012] When the ratio of the power of the tractor power battery pack to the power of the powered trailer power battery pack is within the set ratio range, determine the distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer according to the driving conditions of the whole vehicle, and determine the driving torque of the tractor and the driving torque of the powered trailer according to the distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer and the driving torque required by the whole vehicle; the lower limit of the set ratio range is less than 1; the upper limit of the set ratio range is greater than 1;

[0013] When the ratio of the power of the tractor power battery pack to the power of the powered trailer power battery pack is greater than the upper limit of the set ratio range, decrease the driving torque of the powered trailer and increase the driving torque of the tractor;

[0014] When the ratio of the power of the tractor power battery pack to the power of the powered trailer power battery pack is less than the lower limit of the set ratio range, increase the driving torque of the powered trailer and decrease the driving torque of the tractor.

[0015] In a third aspect, the present application provides an electric tractor with a powered trailer. The electric tractor with a powered trailer includes a tractor, a powered trailer, and the cruising range control system of the electric tractor with a powered trailer according to the first aspect; the powered trailer is used to provide auxiliary power for the tractor.

[0016] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0017] The present application provides a powered-trailer electric tractor, a cruising range control system and method. The cruising range control system includes: a data acquisition module for acquiring target data; a control module for, when the ratio of the power battery pack power of the tractor to that of the powered trailer is within a set ratio range, determining the distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer according to the vehicle running condition, and then determining the driving torque of the tractor and the driving torque of the powered trailer according to the required driving torque of the whole vehicle; when the ratio of the power battery pack power of the tractor to that of the powered trailer is greater than the upper limit of the set ratio range, reducing the driving torque of the powered trailer and increasing the driving torque of the tractor; and when the ratio of the power battery pack power of the tractor to that of the powered trailer is less than the lower limit of the set ratio range, increasing the driving torque of the powered trailer and reducing the driving torque of the tractor. By adopting a powered-trailer electric tractor and distributing and adjusting the driving torques of the powered trailer and the main vehicle based on the power battery pack powers of the tractor and the powered trailer and the vehicle running condition, the present application increases the cruising range of the whole tractor and enhances its power performance compared with the traditional electric tractor, and solves the problem of insufficient power output in case of heavy load, climbing or acceleration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 Schematic diagram of a cruising range control system for a powered-trailer electric tractor provided by an embodiment of the present application;

[0020] Figure 2 Schematic diagram of a cruising range control method for a powered-trailer electric tractor provided by an embodiment of the present application;

[0021] Figure 3 Schematic diagram of the power supply system structure of a tractor-trailer provided by an embodiment of the present application;

[0022] Figure 4 Schematic diagram of the electrical principle of a tractor-trailer provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0024] The available assembled power of the power battery of an electric tractor (also referred to as a towing train in this article) is limited by the overall vehicle space layout. Relying solely on its own battery pack for power supply, the battery capacity is limited, and the cruising range is short, making it difficult to meet the requirements of medium- and long-distance trunk transportation. It may be necessary to charge frequently, resulting in low transportation efficiency. Moreover, in the face of heavy loads, climbing slopes, accelerating, etc., relying solely on the power system of the tractor itself may result in insufficient power output, causing the vehicle to travel slowly, have difficulty climbing slopes, and even affect the completion of normal transportation tasks. At the same time, the mechanical energy generated by the trailer of the tractor during braking or downhill cannot be effectively converted into electrical energy and stored, resulting in energy waste and reduced energy utilization efficiency. For traditional electric towing vehicles, the present application provides an electric tractor with a powered trailer. The electric tractor with a powered trailer includes a tractor (also referred to as the main vehicle in this article), a powered trailer (abbreviated as the trailer), and a cruising control system. The powered trailer is a trailer with a power battery system and an electric drive axle. The powered trailer is used to provide auxiliary power for the tractor.

[0025] Parameter description:

[0026] 1) Driving torque T1, driving force F1, and corresponding motor power P1 of the main vehicle (tractor);

[0027] 2) Driving torque T2, driving force F2, and corresponding motor power P2 of the trailer (powered trailer);

[0028] 3) Battery system power Q1, state of charge soc1 of the main vehicle power battery system, battery system power Q2, state of charge soc2 of the trailer power battery system, maximum discharge power P1max of the main vehicle battery system, maximum discharge power P2max of the trailer battery system, power difference ▽Q between the main vehicle battery system and the trailer battery system, dynamic adjustment efficiency factor η1 of the main vehicle battery power, and dynamic adjustment efficiency factor η2 of the trailer battery power;

[0029] 4) Required driving torque T0, driving force F0, and corresponding motor power P0 of the entire vehicle (main vehicle + trailer);

[0030] 5) Output power of the DCDC converter is Pd, and maximum output power is Pmax.

[0031] To make the above objects, features, and advantages of the present application more obvious and understandable, the following further details the present application in conjunction with the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] In an exemplary embodiment, as Figure 1 shown, a cruising range control system for a power-assisted trailer electric tractor is provided. The power-assisted trailer electric tractor includes a tractor and a power trailer, and the power trailer is used to provide auxiliary power for the tractor. The cruising range control system for the power-assisted trailer electric tractor includes:

[0034] A data acquisition module for acquiring target data. The target data includes the battery pack power Q1 of the tractor, the battery pack power Q2 of the power trailer, the total driving torque T0 required for the whole vehicle, and the driving conditions of the whole vehicle. The whole vehicle includes a tractor and a power trailer;

[0035] A control module for, when the ratio R of the battery pack power Q1 of the tractor to the battery pack power Q2 of the power trailer is within a set proportional range, determining the distribution ratio of the driving torque T1 of the tractor and the driving torque T2 of the power trailer according to the driving conditions of the whole vehicle, and determining the driving torque T1 of the tractor and the driving torque T2 of the power trailer according to the distribution ratio of the driving torque T1 of the tractor and the driving torque T2 of the power trailer and the total driving torque required for the whole vehicle. The lower limit of the set proportional range is less than 1, and the upper limit of the set proportional range is greater than 1;

[0036] When the ratio R of the battery pack power Q1 of the tractor to the battery pack power Q2 of the power trailer is greater than the upper limit of the set proportional range, reducing the driving torque T2 of the power trailer and increasing the driving torque T1 of the tractor;

[0037] And when the ratio R of the battery pack power Q1 of the tractor to the battery pack power Q2 of the power trailer is less than the lower limit of the set proportional range, increasing the driving torque T2 of the power trailer and reducing the driving torque T1 of the tractor.

[0038] The general principle of driving torque distribution is as follows:

[0039] 1) On the premise of ensuring driving safety, give priority to using the driving torque of the tractor and reduce the power output of the trailer.

[0040] 2) When the battery power of the tractor is low, gradually increase the power output of the trailer to balance the power consumption of the two.

[0041] 3) Under high-power demand conditions such as acceleration and climbing, make full use of the driving torques of both the tractor and the trailer at the same time.

[0042] Driving torque distribution under different working conditions:

[0043] Low-speed cruising condition: The tractor is the main driving source, and the trailer does not participate in driving or only provides a small driving torque.

[0044] Acceleration condition: The driving torques of both the tractor and the trailer are utilized simultaneously to ensure the acceleration performance of the whole vehicle.

[0045] Climbing condition: Increase the driving torque output of the trailer to improve the traction force of the whole vehicle.

[0046] Downhill or coasting condition: Reduce the energy consumption of the drive system, give priority to the power output of the tractor, and the trailer operates at low power or does not participate in driving.

[0047] Based on the above distribution strategy, as an alternative implementation, when the ratio R of the battery power Q1 of the tractor power battery pack and the battery power Q2 of the powered trailer battery pack is within the set proportional range, in terms of determining the distribution ratio of the driving torque T1 of the tractor and the driving torque T2 of the powered trailer according to the driving condition of the whole vehicle, the control module is used for:

[0048] When the driving condition of the whole vehicle is the low-speed cruising condition, the driving torques of the tractor and the powered trailer are respectively distributed as 90% and 10% of the driving torque T0 required by the whole vehicle.

[0049] When the driving condition of the whole vehicle is the acceleration condition, the driving torques of the tractor and the powered trailer are respectively distributed as 70% and 30% of the driving torque T0 required by the whole vehicle.

[0050] When the driving condition of the whole vehicle is the climbing condition, the driving torques of the tractor and the powered trailer are respectively distributed as 60% and 40% of the driving torque T0 required by the whole vehicle.

[0051] And when the driving condition of the whole vehicle is the downhill condition or the coasting condition, the driving torques of the tractor and the powered trailer are respectively distributed as 95% and 5% of the driving torque T0 required by the whole vehicle.

[0052] In the above implementation, the determination method of the distribution ratio is a fixed distribution method, that is, the distribution ratio under different conditions remains unchanged.

[0053] The following provides an implementation of a non-fixed distribution method: The distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer includes an initial distribution ratio and a current distribution ratio; the initial distribution ratio is a preset distribution ratio used when the driving torques of the tractor and the powered trailer are first distributed under each driving condition of the whole vehicle; the current distribution ratio is a distribution ratio determined in real time as the vehicle runs under each driving condition of the whole vehicle.

[0054] Among them, the initial distribution ratio under each vehicle driving condition is determined by testing several distribution ratios under each vehicle driving condition.

[0055] The determination process of the current distribution ratio under each vehicle driving condition is as follows:

[0056] 1) According to several groups of historical performance parameters, optimization objectives, and constraint conditions under the vehicle driving condition, using a multi-objective optimization algorithm, a set of optimal performance parameters is obtained; the optimization objectives include an energy efficiency objective and a dynamic performance objective.

[0057] 2) According to a set of the optimal performance parameters, the current distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer is determined.

[0058] As an optional implementation manner, the specific process for determining the initial distribution ratio under each vehicle driving condition is as follows:

[0059] 1) Establish a test environment and a design objective mathematical model (vehicle dynamics model), and set several distribution ratios of the driving torque of the tractor and the driving torque of the powered trailer within a certain range; among them, the design objective mathematical model is constructed according to the performance indicators (of the vehicle). The certain range can be determined based on engineering experience.

[0060] 2) In the test environment, test and obtain the set of performance indicators under each distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer.

[0061] 3) According to the design objective mathematical model, calculate the design objective values corresponding to the set of performance indicators under each distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer.

[0062] 4) Select the distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer corresponding to the optimal design objective value.

[0063] The initial distribution ratio of the driving torque under each condition can be denoted as K0, and K0 is also called the basic distribution coefficient. That is to say, K0 is determined according to the design objectives (design objective mathematical model) of different conditions, vehicle performance, and engineering experience. It is mainly to calculate the vehicle performance indicators under different distribution ratios through the vehicle dynamics model, and determine the actual performance of different K0s through experiments or simulations. The process is as follows:

[0064] 1) On a test bench or in a real vehicle, test several driving torque distribution ratios (such as 85%:15%, 90%:10%, 95%:5%).

[0065] 2) Record key performance indicators: acceleration time, climbing ability, energy consumption, tire slip ratio, etc. Select the optimal ratio as K0 according to the design goal. The performance indicators describe the performance of the whole vehicle, and each performance indicator is determined by multiple parameters (performance parameters), which are collected by sensors.

[0066] During the operation of the tractor whole vehicle, the current distribution ratio of the driving torques of the prime mover and the trailer can be dynamically optimized using a multi-objective optimization algorithm according to the battery capacities of the prime mover and the trailer, vehicle body stability, vehicle driving states (starting, climbing), etc. At the same time, when the speed of the tractor-trailer exceeds 15 km / h, with the goal that the propulsion force of the trailer does not exceed that of the prime mover, dynamically adjust the driving forces of the prime mover and the trailer to avoid tire slippage.

[0067] The following further illustrates the dynamic optimization using a multi-objective optimization algorithm through an example:

[0068] 1) Key optimization objectives and their quantification indicators.

[0069] a. Energy efficiency objective (endurance objective): total energy consumption (battery consumption of the prime mover and the trailer), energy recovered by regenerative braking, ratio of power demand to battery capacity.

[0070] b. Dynamic performance objective (traction force objective): acceleration ability (such as 0 - 60 km / h time), ramp climbing ability, matching degree of driving torque and vehicle load.

[0071] 2) Constraint conditions, that is, the hard limits to be satisfied during the optimization process.

[0072] a. Stability constraints, whose quantification indicators include dynamic parameters such as vehicle lateral slip ratio, yaw rate, centroid acceleration, tire adhesion coefficient utilization rate, etc. The influence of driving torque distribution on stability can be described by establishing a vehicle dynamics model (such as a single-track model, multi-body dynamics model).

[0073] b. Lower limit of battery SOC (for example, prime mover SOC ≥ 20%, trailer SOC ≥ 15%).

[0074] c. Range of driving torque distribution ratio (such as the prime mover's share [40%, 80%], to avoid unilateral overload caused by extreme distribution).

[0075] d. Tire adhesion coefficient limit (driving torque ≤ μ·N, where μ is the friction coefficient and N is the vertical load).

[0076] e. Battery life protection: balance of the state of charge (SOC) of the prime mover and trailer batteries, avoidance of overcharging / discharging, temperature control, etc.

[0077] f. Safety constraints: prevent tire skidding (e.g., longitudinal adhesion coefficient ≤ 1), prevent vehicle out-of-control (e.g., yaw rate does not exceed the threshold).

[0078] 3) Multi-objective optimization algorithms: SPEA2 (Strength Pareto Evolutionary Algorithm 2), NSGA-II, etc. can be used.

[0079] 4) Dynamic optimization process.

[0080] a. Definition of objective function:

[0081] Define the objective function (the objective to be minimized or maximized) and the constraint conditions. Among them, each optimization objective corresponds to an objective function.

[0082] b. Real-time data (parameters) acquisition:

[0083] Obtain the current state parameters through sensors: power battery SOC, vehicle speed, slope, tire adhesion coefficient, acceleration, driving torque, etc.

[0084] c. Switch the weights of each optimization objective according to the driving state / operating conditions (starting, climbing, cruising, etc.).

[0085] Dynamic target adjustment: Adjust the priority of each optimization objective according to the real-time operating conditions (switch the weights of each optimization objective). For example:

[0086] Starting / acceleration stage: Traction is prioritized, and energy efficiency is sacrificed appropriately.

[0087] When climbing: Balance the traction and the limit of tire adhesion coefficient.

[0088] Flat road cruising: Aim at energy efficiency and maximize SOC balance.

[0089] Since the downhill operating condition or the coasting operating condition pays more attention to energy recovery and braking, the dynamic optimization of the driving torque distribution ratio is not carried out.

[0090] d. Multi-objective optimization: Based on multiple sets of historical parameters corresponding to the current operating conditions and each optimization objective, use multi-objective optimization algorithms such as NSGA-II to iteratively optimize and obtain a set of optimal parameters corresponding to the current operating conditions.

[0091] Generally, multiple sets of optimized parameters (solution sets) will be obtained through the multi-objective optimization algorithm. The optimal set can be selected through methods such as weighted summation method or rule base, that is, a set of optimal parameters corresponding to the current operating conditions is obtained.

[0092] Update the objective function and constraint conditions according to the latest data in each iteration to ensure dynamic adaptation to environmental changes.

[0093] e. Decision-making and control instruction output:

[0094] Based on a set of optimal parameters corresponding to the current working condition, determine the driving torque ratio (i.e., the current distribution ratio), and send it to the motor controllers of the tractor and the trailer.

[0095] f. Closed-loop feedback and continuous optimization:

[0096] Monitor the actual state after execution. If there is a deviation (such as the aggravation of SOC imbalance), that is, it does not meet the constraint conditions, then re-trigger the optimization process.

[0097] As an alternative implementation, the target data further includes the voltage of the power battery pack of the tractor and the voltage of the power battery pack of the powered trailer; when the ratio R of the power battery pack power Q1 of the tractor and the power battery pack power Q2 of the powered trailer is greater than the upper limit of the set ratio range, in terms of reducing the driving torque T2 of the powered trailer and increasing the driving torque T1 of the tractor, the control module is used for:

[0098] When the ratio of the power battery pack power of the tractor and the power battery pack power of the powered trailer is greater than the upper limit of the set ratio range, according to the first torque adjustment model: T1’ = T1×(1 + η1), adjust the driving torque of the tractor to increase the driving torque of the tractor; where, T1 is the driving torque of the tractor before adjustment, T1’ is the driving torque of the tractor after adjustment, η1 represents the tractor efficiency factor, η1 = V1×Q1 / (V1×Q1 + V2×Q2), V1 represents the voltage of the power battery pack of the tractor; Q1 represents the power battery pack power of the tractor; V2 represents the voltage of the power battery pack of the powered trailer; Q2 represents the power battery pack power of the powered trailer;

[0099] When the ratio of the power battery pack power of the tractor and the power battery pack power of the powered trailer is greater than the upper limit of the set ratio range, according to the second driving torque adjustment model: T2’ = T2×(1 - η2), adjust the driving torque of the powered trailer to reduce the driving torque of the powered trailer; where, T2 is the driving torque of the powered trailer before adjustment, T2’ is the driving torque of the powered trailer after adjustment, η2 represents the powered trailer efficiency factor, η2 = V2×Q2 / (V1×Q1 + V2×Q2).

[0100] As an alternative implementation, the target data further includes the voltage of the power battery pack of the tractor and the voltage of the power battery pack of the powered trailer; when the ratio R of the power battery pack power Q1 of the tractor and the power battery pack power Q2 of the powered trailer is less than the lower limit of the set ratio range, in terms of increasing the driving torque T2 of the powered trailer and reducing the driving torque T1 of the tractor, the control module is used for:

[0101] When the ratio of the power of the traction vehicle's power battery pack to the power of the powered trailer's power battery pack is less than the lower limit of the set ratio range, according to the third driving torque adjustment model: T1’ = T1×(1 - η1), the driving torque of the traction vehicle is adjusted to reduce the driving torque of the traction vehicle; where T1 is the driving torque of the traction vehicle before adjustment, T1’ is the driving torque of the traction vehicle after adjustment, η1 represents the efficiency factor of the traction vehicle, η1 = V1×Q1 / (V1×Q1 + V2×Q2), V1 represents the voltage of the traction vehicle's power battery pack; Q1 represents the power of the traction vehicle's power battery pack; V2 represents the voltage of the powered trailer's power battery pack; Q2 represents the power of the powered trailer's power battery pack;

[0102] When the ratio of the power of the traction vehicle's power battery pack to the power of the powered trailer's power battery pack is less than the lower limit of the set ratio range, according to the fourth driving torque adjustment model: T2’ = T2×(1 + η2), the driving torque of the powered trailer is adjusted to increase the driving torque of the powered trailer; where T2 is the driving torque of the powered trailer before adjustment, T2’ is the driving torque of the powered trailer after adjustment, η2 represents the efficiency factor of the powered trailer, η2 = V2×Q2 / (V1×Q1 + V2×Q2).

[0103] As an optional implementation, the lower limit of the set ratio range is 0.6, and the upper limit of the set ratio range is 1.5.

[0104] That is to say, in this embodiment, in order to balance the power consumption of the traction vehicle and the trailer and avoid excessive discharge caused by a relatively low battery voltage, it is necessary to combine the real-time monitored battery powers Q1 and Q2 and battery system voltages V1 and V2 to dynamically adjust the actual output driving torques of the traction vehicle and the trailer under the above various working conditions. Specifically, according to the ratio of their remaining capacities: R = Q1 / Q2; when 0.6 ≤ R ≤ 1.5, the output torque of the traction vehicle is T1 and the output torque of the trailer is T2 as the target for adjustment (that is, according to the allocation method corresponding to when the ratio of the power of the traction vehicle's power battery pack to the power of the powered trailer's power battery pack is within the set ratio range); when R > 1.5, the driving torque output of the trailer is reduced, and the actual output torque is adjusted with the driving torque of the traction vehicle = T1×(1 + η1) and the driving torque of the trailer = T2×(1 - η2) as the target; when R < 0.6, the driving torque output of the trailer is increased, and the actual output torque is adjusted with the driving torque of the traction vehicle = T1×(1 - η1) and the driving torque of the trailer = T2×(1 + η2) as the target.

[0105] In another exemplary embodiment, the target data further includes the working power P1 of the traction vehicle motor, the maximum discharge power P1max of the traction vehicle power battery pack, the working power P2 of the powered trailer motor, and the maximum discharge power P2max of the powered trailer power battery pack, and the control module is further configured to:

[0106] When the ratio of the power Q1 of the traction vehicle's power battery pack to the power Q2 of the powered trailer's power battery pack is greater than the upper limit of the set ratio range, or when the working power P1 of the traction vehicle's motor is less than the maximum discharge power P1max of the traction vehicle's power battery pack and the working power P2 of the powered trailer's motor is greater than the maximum discharge power P2max of the powered trailer's power battery pack, output a first DCDC converter (bidirectional DCDC) control instruction, and the first DCDC converter control instruction is used to control the DCDC converter to transfer the power of the traction vehicle's power battery pack to the powered trailer;

[0107] And when the ratio of the power Q2 of the powered trailer's power battery pack to the power Q1 of the traction vehicle's power battery pack is greater than the upper limit of the set ratio range, or when the working power P2 of the powered trailer's motor is less than the maximum discharge power P2max of the powered trailer's power battery pack and the working power P1 of the traction vehicle's motor is greater than the maximum discharge power P1max of the traction vehicle's power battery pack, output a second DCDC converter control instruction, and the second DCDC converter control instruction is used to control the DCDC converter to transfer the power of the powered trailer's power battery pack to the traction vehicle.

[0108] That is, the electric traction vehicle with a powered trailer further includes a DCDC converter. Functions of the DCDC converter: 1) Realize the energy flow between the traction vehicle and the trailer's power battery packs, and improve the dynamic performance of the traction train. 2) When the power of the traction vehicle or the trailer's power battery is low, transfer energy through the DCDC converter to balance the power consumption of both, and improve the endurance of the traction train.

[0109] When the upper limit of the set ratio range is 1.5, that is, when Q1>1.5Q2 or Q2>1.5Q1, the DCDC converter will be started.

[0110] As an optional implementation manner, the main control module is further configured to output a DCDC converter control instruction and control the DCDC converter to stop working when the absolute value (|▽Q|) of the difference between the power Q1 of the traction vehicle's power battery pack and the power Q2 of the powered trailer's power battery pack is less than the second set ratio threshold with respect to the sum (Q1 + Q2) of the power Q1 of the traction vehicle's power battery pack and the power Q2 of the powered trailer's power battery pack.

[0111] As an optional implementation manner, the second set ratio threshold is 0.2.

[0112] That is to say, the balance target of the DCDC converter's dynamic balance strategy is to keep the difference in power between the traction vehicle and the trailer's power batteries within a reasonable range: |▽Q| ≤ 0.2(Q1 + Q2).

[0113] In addition, in some embodiments, the output power of the DCDC converter is adjusted according to the magnitude of ▽Q: Pd = k▽Q, where k is a proportionality coefficient used to regulate the energy transfer rate. Direction control: When Q1 > Q2, the tractor outputs energy to the trailer; when Q2 > Q1, the trailer outputs energy to the tractor.

[0114] By monitoring the voltage and power between the tractor and the trailer in real time, it is ensured that the power output of the DCDC converter should be as small as possible to reduce energy loss and the required rated power of the DCDC converter, thereby reducing costs.

[0115] Power limit of the DCDC converter The maximum power of the DCDC converter is P max, and exceeding this limit should be avoided during actual operation. In some embodiments, when the power difference is large, a phased energy transfer strategy is adopted:

[0116] Stage 1: Pd = P max;

[0117] Stage 2: When the power difference decreases to a certain extent, Pd is gradually reduced, that is, it operates according to Pd = k▽Q.

[0118] Embodiment 2

[0119] Based on the same technical concept as Embodiment 1, in another exemplary embodiment, a method for controlling the endurance of an electric tractor with a powered trailer is provided. The electric tractor with a powered trailer includes a tractor and a powered trailer, and the powered trailer is used to provide auxiliary power for the tractor; refer to Figure 2 , the method for controlling the endurance of the electric tractor with a powered trailer includes:

[0120] Step 101, obtain target data; the target data includes the battery pack power Q1 of the tractor, the battery pack power Q2 of the powered trailer, the total vehicle required driving torque T0, and the total vehicle driving condition; the total vehicle includes the tractor and the powered trailer;

[0121] Step 102, when the ratio R of the battery pack power Q1 of the tractor and the battery pack power Q2 of the powered trailer is within a set proportional range, determine the distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer according to the total vehicle driving condition, and determine the driving torque of the tractor and the driving torque of the powered trailer according to the distribution ratio of the driving torque of the tractor and the driving torque of the powered trailer and the total vehicle required driving torque T0; the lower limit of the set proportional range is less than 1; the upper limit of the set proportional range is greater than 1;

[0122] Step 103, when the ratio R of the power battery pack power Q1 of the tractor and the power battery pack power Q2 of the powered trailer is greater than the upper limit of the set ratio range, reduce the driving torque T2 of the powered trailer and increase the driving torque T1 of the tractor;

[0123] Step 104, when the ratio R of the power battery pack power Q1 of the tractor and the power battery pack power Q2 of the powered trailer is less than the lower limit of the set ratio range, increase the driving torque T2 of the powered trailer and reduce the driving torque T1 of the tractor.

[0124] As an alternative implementation, the target data further includes the power battery pack voltage of the tractor and the power battery pack voltage of the powered trailer; Step 103 specifically includes:

[0125] When the ratio of the power battery pack power of the tractor and the power battery pack power of the powered trailer is greater than the upper limit of the set ratio range, according to the first torque adjustment model: T1’ = T1×(1 + η1), adjust the driving torque of the tractor to increase the driving torque of the tractor; where, T1 is the driving torque of the tractor before adjustment, T1’ is the driving torque of the tractor after adjustment, η1 represents the tractor efficiency factor, η1 = V1×Q1 / (V1×Q1 + V2×Q2), V1 represents the power battery pack voltage of the tractor; Q1 represents the power battery pack power of the tractor; V2 represents the power battery pack voltage of the powered trailer; Q2 represents the power battery pack power of the powered trailer;

[0126] And, according to the second driving torque adjustment model: T2’ = T2×(1 - η2), adjust the driving torque of the powered trailer to reduce the driving torque of the powered trailer; where, T2 is the driving torque of the powered trailer before adjustment, T2’ is the driving torque of the powered trailer after adjustment, η2 represents the powered trailer efficiency factor, η2 = V2×Q2 / (V1×Q1 + V2×Q2).

[0127] As an alternative implementation, the target data further includes the power battery pack voltage of the tractor and the power battery pack voltage of the powered trailer; Step 104 specifically includes:

[0128] When the ratio of the power of the traction vehicle's power battery pack to the power of the powered trailer's power battery pack is less than the lower limit of the set ratio range, according to the third driving torque adjustment model: T1’ = T1×(1 - η1), the driving torque of the traction vehicle is adjusted to reduce the driving torque of the traction vehicle; where, T1 is the driving torque of the traction vehicle before adjustment, T1’ is the driving torque of the traction vehicle after adjustment, η1 represents the efficiency factor of the traction vehicle, η1 = V1×Q1 / (V1×Q1 + V2×Q2), V1 represents the voltage of the traction vehicle's power battery pack; Q1 represents the power of the traction vehicle's power battery pack; V2 represents the voltage of the powered trailer's power battery pack; Q2 represents the power of the powered trailer's power battery pack;

[0129] And, according to the fourth driving torque adjustment model: T2’ = T2×(1 + η2), the driving torque of the powered trailer is adjusted to increase the driving torque of the powered trailer; where, T2 is the driving torque of the powered trailer before adjustment, T2’ is the driving torque of the powered trailer after adjustment, η2 represents the efficiency factor of the powered trailer, η2 = V2×Q2 / (V1×Q1 + V2×Q2).

[0130] As an alternative implementation, the target data further includes the working power P1 of the traction vehicle motor, the maximum discharge power P1max of the traction vehicle's power battery pack, the working power P2 of the powered trailer motor, and the maximum discharge power P2max of the powered trailer's power battery pack. The endurance control method for the electric traction vehicle with a powered trailer further includes:

[0131] Step 105, when the ratio of the power of the traction vehicle's power battery pack Q1 to the power of the powered trailer's power battery pack Q2 is greater than the upper limit of the set ratio range, or when the working power P1 of the traction vehicle motor is less than the maximum discharge power P1max of the traction vehicle's power battery pack and the working power P2 of the powered trailer motor is greater than the maximum discharge power P2max of the powered trailer's power battery pack, output a first DCDC converter control instruction, and the first DCDC converter control instruction is used to control the DCDC converter to transfer the power of the traction vehicle's power battery pack to the powered trailer;

[0132] Step 106, when the ratio of the power of the powered trailer's power battery pack Q2 to the power of the traction vehicle's power battery pack Q1 is greater than the upper limit of the set ratio range, or when the working power P2 of the powered trailer motor is less than the maximum discharge power P2max of the powered trailer's power battery pack and the working power P1 of the traction vehicle motor is greater than the maximum discharge power P1max of the traction vehicle's power battery pack, output a second DCDC converter control instruction, and the second DCDC converter control instruction is used to control the DCDC converter to transfer the power of the powered trailer's power battery pack to the traction vehicle.

[0133] Embodiment 3

[0134] Refer to Figure 3 and Figure 4 In another exemplary embodiment, a powered trailer electric tractor is provided. The powered trailer electric tractor includes a tractor, a powered trailer, and a range control system of the powered trailer electric tractor described in Embodiment 2; the powered trailer is used to provide auxiliary power for the tractor.

[0135] The range control system is built into the microcontroller of the main control module.

[0136] As Figure 3 shown, the two positive terminals of the DCDC converter are respectively connected to the positive pole of the main vehicle power battery pack and the positive pole of the trailer power battery pack, and the two negative terminals of the DCDC converter are respectively connected to the negative pole of the main vehicle power battery pack and the negative pole of the trailer power battery pack. And, the two positive terminals of the DCDC converter are also respectively connected to the integrated controller 1 and the integrated controller 2. Relays are provided in the integrated controller 1 and the integrated controller 2 to control the disconnection and connection of the positive power supply terminals of the load devices (excluding the drive motor) of the main vehicle and the trailer from the positive pole of the power battery pack.

[0137] Figure 4 In, the battery management system 1 is mainly responsible for monitoring the battery voltage, current and temperature, SOC1, and battery charge Q1 of the main vehicle power battery system, determining the maximum discharge power P1max of the main vehicle battery, and communicating with the battery management system 3. At the same time (according to the instructions sent by the main control module), it controls the closed state of the high-voltage circuit through the negative relay 1. In Figure 4 The arrow lines in indicate the communication relationship. The single arrow indicates one-way communication, and the double arrow indicates two-way communication.

[0138] The battery management system 2 is mainly responsible for monitoring the battery voltage, current and temperature, SOC2, and battery charge Q2 of the trailer power battery system, determining the maximum discharge power P2max of the trailer battery, and communicating with the battery management system 3. At the same time (according to the instructions sent by the main control module), it controls the closed state of the high-voltage circuit through the negative relay 2.

[0139] The battery management system 3 mainly communicates with the battery management systems 1 and 2, reports information to the main control module through the battery management systems 1 and 2, estimates the total SOC of the tractor-trailer and communicates with other components of the vehicle. At the same time (according to the instructions sent by the main control module), it controls the high-voltage states of the main vehicle and the trailer through the positive relays 1 and 2.

[0140] The "trailer load" under "drive motor 2" in the "trailer load" dotted box specifically refers to high-voltage electrical loads such as the high-voltage braking load system and the trailer power battery thermal management system.

[0141] In the main control module, the monitoring module mainly monitors the working state of the whole vehicle and transmits the monitoring information (such as battery power, voltage, SOC, maximum discharge power of the power battery pack, driving torque, etc.) to the microcontroller, and then controls the working states of the drive motor and the power battery through the microcontroller. In this process, CAN communication is carried out with other system parts (such as the battery management system 3, trailer load and main vehicle load) through communication components to achieve the functions of monitoring and controlling the whole vehicle state.

[0142] The main control module controls the operating state of the bidirectional DCDC through CAN communication instructions, and distributes / adjusts the driving torques of drive motor 1 and drive motor 2, etc. In addition, the main control module also sends instructions to integrated controller 1 and integrated controller 2 to turn on or off the positive power input terminals of the main vehicle load and the trailer load.

[0143] The solution proposed in this embodiment adds a power source and a drive motor to the trailer. At the same time, through the high-voltage connection method of the power sources of the main vehicle and the trailer and the coordinated control between the main vehicle and the trailer, the cruising range and power performance of the train are improved, the operation cost is reduced, and the trailer is equipped with an independent drive system, which works in coordination with the power system of the tractor to provide additional power under working conditions such as acceleration and climbing, improving the overall power performance of the vehicle and enabling it to adapt to various complex road conditions. In addition, during vehicle braking or downhill, the mechanical energy of the trailer can be converted into electrical energy and stored to achieve the recycling of energy and improve the energy utilization efficiency.

[0144] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered as the scope recorded in this specification.

[0145] Specific examples are used in this article to elaborate on the principles and implementation methods of this application. The descriptions of the above embodiments are only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, based on the idea of this application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A cruising range control system for an electric tractor with a power hook, characterized in that: The electric tractor with power trailer comprises a tractor and a power trailer, wherein the power trailer is used to provide auxiliary power for the tractor; The endurance control system of the electric tractor with power hook comprises: A data acquisition module, used to acquire target data; The target data includes the power of the tractor's power battery pack, the power of the power trailer's power battery pack, the required driving torque of the whole vehicle, and the driving condition of the whole vehicle; the whole vehicle includes the tractor and the power trailer; A control module, for determining the distribution ratio of the tractor driving torque and the power trailer driving torque according to the driving condition of the whole vehicle when the ratio of the power of the tractor power battery pack to the power of the power trailer power battery pack is within a set ratio range, and determining the tractor driving torque and the power trailer driving torque according to the distribution ratio of the tractor driving torque and the power trailer driving torque and the driving torque required by the whole vehicle; the lower limit of the set ratio range is less than 1; the upper limit of the set ratio range is greater than 1; When the ratio of the power of the tractor's power battery pack to the power of the power trailer's power battery pack is greater than the upper limit of the set ratio range, the driving torque of the power trailer is reduced and the driving torque of the tractor is increased; And, when the ratio of the power of the tractor's power battery pack to the power of the power trailer's power battery pack is less than the lower limit of the set ratio range, the driving torque of the power trailer is increased and the driving torque of the tractor is reduced.

2. The cruising range control system of an electric tractor with a power hook according to claim 1, characterized in that: The target data also includes the voltage of the power battery pack of the tractor and the voltage of the power battery pack of the power trailer; when the ratio of the power of the power battery pack of the tractor to the power of the power battery pack of the power trailer is greater than the upper limit of the set ratio range, the driving torque of the power trailer is reduced and the driving torque of the tractor is increased, the control module is used to: When the ratio of the power of the tractor power battery pack to the power of the power trailer power battery pack is greater than the upper limit of the set ratio range, the driving torque of the tractor is adjusted according to the formula T1'=T1×(1+η1) to increase the driving torque of the tractor, and the driving torque of the power trailer is adjusted according to the formula T2'=T2×(1-η2) to reduce the driving torque of the power trailer; Among them, T1 is the driving torque of the tractor before adjustment, T1' is the driving torque of the tractor after adjustment, η1 represents the efficiency factor of the tractor, η1=V1×Q1 / (V1×Q1+V2×Q2), V1 represents the voltage of the power battery pack of the tractor; Q1 represents the power level of the power battery pack of the tractor; V2 represents the voltage of the power battery pack of the power trailer; Q2 represents the power level of the power battery pack of the power trailer; T2 is the driving torque of the power trailer before adjustment, T2' is the driving torque of the power trailer after adjustment, η2 represents the efficiency factor of the power trailer, η2=V2×Q2 / (V1×Q1+V2×Q2).

3. The cruising range control system of an electric tractor with a power hook according to claim 1, characterized in that: The target data also includes the voltage of the power battery pack of the tractor and the voltage of the power battery pack of the power trailer; when the ratio of the power of the power battery pack of the tractor to the power of the power battery pack of the power trailer is less than the lower limit of the set ratio range, the driving torque of the power trailer is increased and the driving torque of the tractor is reduced, the control module is used to: When the ratio of the power of the tractor power battery pack to the power of the power trailer power battery pack is less than the lower limit of the set ratio range, the driving torque of the tractor is adjusted according to the formula T1'=T1×(1-η1) to reduce the driving torque of the tractor, and the driving torque of the power trailer is adjusted according to the formula T2'=T2×(1+η2) to increase the driving torque of the power trailer; Among them, T1 is the driving torque of the tractor before adjustment, T1' is the driving torque of the tractor after adjustment, η1 represents the efficiency factor of the tractor, η1=V1×Q1 / (V1×Q1+V2×Q2), V1 represents the power battery pack voltage of the tractor; Q1 represents the power battery pack charge of the tractor; V2 represents the power battery pack voltage of the power trailer; Q2 represents the power battery pack charge of the power trailer; T2 is the driving torque of the power trailer before adjustment, T2' is the driving torque of the power trailer after adjustment, η2 represents the efficiency factor of the power trailer, η2=V2×Q2 / (V1×Q1+V2×Q2).

4. The cruising range control system of an electric tractor with a power hook according to claim 1, characterized in that: The target data also includes the working power of the tractor motor, the maximum discharge power of the tractor power battery pack, the working power of the power trailer motor, and the maximum discharge power of the power trailer power battery pack. The control module is also used for: When the ratio of the power of the tractor power battery pack to the power of the power trailer power battery pack is greater than the upper limit of the set ratio range, or when the working power of the tractor motor is less than the maximum discharge power of the tractor power battery pack and the working power of the power trailer motor is greater than the maximum discharge power of the power trailer power battery pack, a first DCDC converter control instruction is output, and the first DCDC converter control instruction is used to control the DCDC converter to transfer the power of the tractor power battery pack to the power trailer; Furthermore, when the ratio of the power of the power battery pack of the power trailer to the power battery pack of the tractor is greater than the upper limit of the set ratio range, or when the working power of the motor of the power trailer is less than the maximum discharge power of the power battery pack of the power trailer and the working power of the motor of the tractor is greater than the maximum discharge power of the power battery pack of the tractor, a second DCDC converter control instruction is output, and the second DCDC converter control instruction is used to control the DCDC converter to transfer the power of the power battery pack of the power trailer to the tractor.

5. The cruising range control system of an electric tractor with a power hook according to claim 1, characterized in that: The distribution ratio of the tractor driving torque and the power trailer driving torque includes an initial distribution ratio and a current distribution ratio; the initial distribution ratio is a preset distribution ratio used when the tractor driving torque and the power trailer driving torque are distributed for the first time under each vehicle driving condition; the current distribution ratio is a distribution ratio determined in real time as the vehicle is running under each vehicle driving condition; The initial allocation ratio under each vehicle driving condition is determined by testing several allocation ratios under each vehicle driving condition; The process of determining the current allocation ratio under each vehicle driving condition is as follows: According to a plurality of groups of historical performance parameters, optimization objectives and constraints under the vehicle driving condition, a group of optimal performance parameters is obtained by using a multi-objective optimization algorithm; the optimization objectives include energy efficiency and power performance objectives; According to a set of the optimal performance parameters, a current distribution ratio of the tractor driving torque and the power trailer driving torque is determined.

6. A method for controlling the endurance of an electric tractor with a power hook, characterized in that: The electric tractor with power trailer comprises a tractor and a power trailer, wherein the power trailer is used to provide auxiliary power for the tractor; The endurance control method of the electric tractor with a power hook comprises: Obtaining target data; the target data includes the power of the tractor's power battery pack, the power of the power trailer's power battery pack, the required driving torque of the whole vehicle, and the driving condition of the whole vehicle; the whole vehicle includes the tractor and the power trailer; When the ratio of the power of the tractor's power battery pack to the power of the power trailer's power battery pack is within a set ratio range, the distribution ratio of the tractor's driving torque to the power trailer's driving torque is determined according to the required driving torque of the vehicle and the vehicle's driving conditions; the lower limit of the set ratio range is less than 1; the upper limit of the set ratio range is greater than 1; When the ratio of the power of the tractor's power battery pack to the power of the power trailer's power battery pack is greater than the upper limit of the set ratio range, the driving torque of the power trailer is reduced and the driving torque of the tractor is increased; When the ratio of the power level of the tractor's power battery pack to the power level of the power trailer's power battery pack is less than the lower limit of the set ratio range, the driving torque of the power trailer is increased and the driving torque of the tractor is reduced.

7. The cruising range control method of an electric tractor with a power hook according to claim 6, characterized in that: The target data also includes the voltage of the power battery pack of the tractor and the voltage of the power battery pack of the power trailer; when the ratio of the power of the power battery pack of the tractor to the power of the power battery pack of the power trailer is greater than the upper limit of the set ratio range, the driving torque of the power trailer is reduced and the driving torque of the tractor is increased, specifically including: When the ratio of the power of the tractor power battery pack to the power of the power trailer power battery pack is greater than the upper limit of the set ratio range, the driving torque of the tractor is adjusted according to the formula T1'=T1×(1+η1) to increase the driving torque of the tractor, and the driving torque of the power trailer is adjusted according to the formula T2'=T2×(1-η2) to reduce the driving torque of the power trailer; Among them, T1 is the driving torque of the tractor before adjustment, T1' is the driving torque of the tractor after adjustment, η1 represents the efficiency factor of the tractor, η1=V1×Q1 / (V1×Q1+V2×Q2), V1 represents the voltage of the power battery pack of the tractor; Q1 represents the power level of the power battery pack of the tractor; V2 represents the voltage of the power battery pack of the power trailer; Q2 represents the power level of the power battery pack of the power trailer; T2 is the driving torque of the power trailer before adjustment, T2' is the driving torque of the power trailer after adjustment, η2 represents the efficiency factor of the power trailer, η2=V2×Q2 / (V1×Q1+V2×Q2).

8. The cruising range control method of an electric tractor with a power hook according to claim 6, characterized in that: The target data also includes the voltage of the power battery pack of the tractor and the voltage of the power battery pack of the power trailer; when the ratio of the power of the power battery pack of the tractor to the power of the power battery pack of the power trailer is less than the lower limit of the set ratio range, the driving torque of the power trailer is increased and the driving torque of the tractor is reduced, specifically including: When the ratio of the power of the tractor power battery pack to the power of the power trailer power battery pack is less than the lower limit of the set ratio range, the driving torque of the tractor is adjusted according to the formula T1'=T1×(1-η1) to reduce the driving torque of the tractor, and the driving torque of the power trailer is adjusted according to the formula T2'=T2×(1+η2) to increase the driving torque of the power trailer; Among them, T1 is the driving torque of the tractor before adjustment, T1' is the driving torque of the tractor after adjustment, η1 represents the efficiency factor of the tractor, η1=V1×Q1 / (V1×Q1+V2×Q2), V1 represents the power battery pack voltage of the tractor; Q1 represents the power battery pack charge of the tractor; V2 represents the power battery pack voltage of the power trailer; Q2 represents the power battery pack charge of the power trailer; T2 is the driving torque of the power trailer before adjustment, T2' is the driving torque of the power trailer after adjustment, η2 represents the efficiency factor of the power trailer, η2=V2×Q2 / (V1×Q1+V2×Q2).

9. The cruising range control method of an electric tractor with a power hook according to claim 6, characterized in that: The target data also includes the working power of the tractor motor, the maximum discharge power of the tractor power battery pack, the working power of the power trailer motor, and the maximum discharge power of the power trailer power battery pack. The endurance control method of the electric tractor with a power trailer also includes: When the ratio of the power of the tractor power battery pack to the power of the power trailer power battery pack is greater than the upper limit of the set ratio range, or when the working power of the tractor motor is less than the maximum discharge power of the tractor power battery pack and the working power of the power trailer motor is greater than the maximum discharge power of the power trailer power battery pack, a first DCDC converter control instruction is output, and the first DCDC converter control instruction is used to control the DCDC converter to transfer the power of the tractor power battery pack to the power trailer; When the ratio of the power battery pack of the power trailer to the power battery pack of the tractor is greater than the upper limit of the set ratio range, or when the working power of the power trailer motor is less than the maximum discharge power of the power battery pack of the power trailer and the working power of the tractor motor is greater than the maximum discharge power of the tractor power battery pack, a second DCDC converter control instruction is output, and the second DCDC converter control instruction is used to control the DCDC converter to transfer the power of the power battery pack of the power trailer to the tractor.

10. An electric tractor with a power hook, characterized in that: The electric tractor with a power trailer comprises a tractor, a power trailer and the cruising control system of the electric tractor with a power trailer as described in any one of claims 1 to 5; the power trailer is used to provide auxiliary power for the tractor.

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