Dynamic efficiency matching method and system for pure electric land leveler

Abstract

The invention relates to the field of land levelers, and particularly discloses a dynamic efficiency matching method and system for a pure electric land leveler. Detecting driver operation actions, and calculating required hydraulic oil total flow according to the driver operation actions; based on the hydraulic oil pressure in the hydraulic loop and the total flow of the required hydraulic transmission medium, finding out the motor rotating speed corresponding to the maximum total driving efficiency of the working device through a circulating optimization algorithm, and recording the motor rotating speed as the optimal motor rotating speed; and generating an actual execution rotating speed instruction according to the optimal motor rotating speed, and issuing the instruction to a working device motor controller. The motor parameters of the working device are dynamically adjusted according to the actual working conditions, and energy efficiency maximization and performance optimization are achieved.

Description

Technical Field

[0001] The present invention relates to the field of motor graders, and in particular to a dynamic performance matching method and system for a pure electric motor grader. Background Art

[0002] In today's rapidly changing technological field, pure electric motor graders, as an important member of construction machinery, have shown great potential in environmental protection and energy conservation with their advantages such as zero emissions, low noise and high efficiency.

[0003] In the existing technology, pure electric graders mainly realize their motion functions through motor drive. As the core power source, the performance of the motor directly determines the overall working efficiency and work quality of the grader. However, traditional control systems often rely on preset parameters when managing these functions. This "one-size-fits-all" approach is inadequate when faced with changing working conditions and load requirements.

[0004] In actual applications, the operating conditions of the grader are complex and changeable, which will affect the operating state of the motor and thus the overall performance of the grader. If the control system cannot make real-time adjustments based on these operating changes, the motor may not be able to operate at its optimal state, resulting in low energy efficiency and slow response.

[0005] In particular, the problem of parameter matching between the working device motor and the load equipment (such as load-sensitive pumps) is particularly prominent. Traditional control systems often use fixed control strategies and cannot be dynamically adjusted according to the real-time needs of the operating action, resulting in low energy efficiency and slow response speed. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a pure electric motor grader dynamic performance matching method and system, which dynamically adjusts the motor parameters of the working device according to actual working conditions to achieve energy efficiency maximization and performance optimization.

[0007] In a first aspect, the technical solution of the present invention provides a method for matching the dynamic performance of a pure electric grader, which specifically includes the following steps: Obtain the hydraulic oil pressure in the hydraulic circuit; Detect the driver's operating actions and calculate the required total flow of hydraulic oil according to the driver's operating actions; Based on the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, the motor speed corresponding to the maximum total efficiency of the working device drive is found through a cyclic optimization algorithm, which is recorded as the optimal motor speed; The optimal motor speed is converted into the actual execution speed command and sent to the motor controller of the working device.

[0008] In an optional implementation, the motor speed corresponding to the maximum working device driving total efficiency is found through a cyclic optimization algorithm, specifically including: Configure minimum motor speed, maximum motor speed and step size; Between the minimum motor speed and the maximum motor speed, a motor speed value is selected every other step and recorded as the target motor speed; The motor working torque is calculated according to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and is recorded as the target motor working torque; Find the motor efficiency corresponding to each set of target motor speed and target motor working torque in the motor efficiency MAP diagram, and record it as the target motor efficiency; The target motor speed is used as the target hydraulic pump speed; Calculate the hydraulic pump working displacement according to the target hydraulic pump speed and the required total flow of hydraulic transmission medium; Find the hydraulic pump efficiency corresponding to each set of target hydraulic pump speed and hydraulic pump working displacement in the hydraulic pump efficiency table, and record it as the target hydraulic pump efficiency; Calculate the total efficiency of the working device drive according to the target motor efficiency and the target hydraulic pump efficiency, and record it as the target total efficiency of the working device drive; The maximum working device driving total efficiency is found among all target working device driving total efficiencies, and the target motor speed corresponding to the maximum working device driving total efficiency is selected and recorded as the optimal motor speed.

[0009] In an optional embodiment, the motor working torque is calculated according to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and is recorded as the target motor working torque, which is specifically calculated by the following formula: Target motor working torque = (hydraulic oil pressure in the hydraulic circuit * required total flow of hydraulic transmission medium) / target motor speed.

[0010] In an optional implementation, the total efficiency of the drive system is calculated according to the target motor efficiency and the target hydraulic pump efficiency, and is recorded as the target total efficiency of the drive system, which is specifically calculated by the following formula: Target drive system total efficiency = target motor efficiency * target hydraulic pump efficiency.

[0011] In a second aspect, the technical solution of the present invention provides a pure electric grader dynamic performance matching system, comprising: Hydraulic oil pressure acquisition module: obtains the hydraulic oil pressure in the hydraulic circuit; Hydraulic oil total flow calculation module: detects the driver's operating actions and calculates the required total hydraulic oil flow according to the driver's operating actions; Optimal motor speed acquisition module: Based on the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, the motor speed corresponding to the maximum working device driving efficiency is found through a cyclic optimization algorithm, which is recorded as the optimal motor speed; Instruction issuing module: generates the actual execution speed instruction from the optimal motor speed and sends it to the motor controller of the working device.

[0012] In an optional implementation, the optimal motor speed acquisition module finds the motor speed corresponding to the maximum working device driving total efficiency through a cyclic optimization algorithm, specifically including: Configure minimum motor speed, maximum motor speed and step size; Between the minimum motor speed and the maximum motor speed, a motor speed value is selected every other step and recorded as the target motor speed; The motor working torque is calculated according to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and is recorded as the target motor working torque; Find the motor efficiency corresponding to each set of target motor speed and target motor working torque in the motor efficiency MAP diagram, and record it as the target motor efficiency; The target motor speed is used as the target hydraulic pump speed; Calculate the hydraulic pump working displacement according to the target hydraulic pump speed and the required total flow of hydraulic transmission medium; Find the hydraulic pump efficiency corresponding to each set of target hydraulic pump speed and hydraulic pump working displacement in the hydraulic pump efficiency table, and record it as the target hydraulic pump efficiency; Calculate the total efficiency of the working device drive according to the target motor efficiency and the target hydraulic pump efficiency, and record it as the target total efficiency of the working device drive; The maximum working device driving total efficiency is found among all target working device driving total efficiencies, and the target motor speed corresponding to the maximum working device driving total efficiency is selected and recorded as the optimal motor speed.

[0013] In an optional embodiment, the motor working torque is calculated according to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and is recorded as the target motor working torque, which is specifically calculated by the following formula: Target motor working torque = (hydraulic oil pressure in the hydraulic circuit * required total flow of hydraulic transmission medium) / target motor speed.

[0014] In an optional implementation, the total efficiency of the drive system is calculated according to the target motor efficiency and the target hydraulic pump efficiency, and is recorded as the target total efficiency of the drive system, which is specifically calculated by the following formula: Target drive system total efficiency = target motor efficiency * target hydraulic pump efficiency.

[0015] A pure electric grader dynamic performance matching method and system provided by the present invention has the following beneficial effects compared with the prior art: the optimal motor speed is calculated in real time according to the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and the speed of the working device motor is adjusted according to different operating conditions, thereby achieving energy efficiency maximization and performance optimization, ensuring that the optimal efficiency can be achieved under different operating conditions, and the motor always operates in the optimal efficiency range, thereby optimizing energy utilization, reducing energy consumption, and extending equipment life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a schematic diagram of the connection between the working device motor (PMSM) and the load sensing pump (LS pump).

[0018] Figure 2 The present invention is a flow chart of a method for matching the dynamic performance of a pure electric grader provided in an embodiment of the present invention.

[0019] Figure 3 It is a flow chart of a specific embodiment of automatic speed control of a working device motor.

[0020] Figure 4 It is the principle diagram of automatic speed control of working device motor based on optimal efficiency.

[0021] Figure 5 It is a simplified schematic diagram of the automatic speed control of the working device motor based on optimal efficiency.

[0022] Figure 6 The present invention provides a schematic block diagram of a dynamic performance matching system for a pure electric motor grader. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0025] The control system hardware of the pure electric motor grader of the embodiment of the present invention includes a main controller and a working device motor controller, both of which are connected to the CAN network and communicate through the CAN network. The main controller performs the automatic speed control of the working device motor with the best efficiency, detects the pressure of the hydraulic oil in the hydraulic circuit, the operation of the driver, calculates the required flow, and finds the best efficiency of the working device motor through a certain algorithm.

[0026] The embodiment of the present invention provides a pure electric motor grader dynamic performance matching method, which improves the convenience and safety of pure electric motor grader operation through automatic speed control of the working device motor, and also significantly improves energy utilization and mechanical life. The automatic speed control of the working device motor is described in detail below.

[0027] Figure 1 It is a connection diagram of the working device motor (PMSM) and the load sensitive pump (LS pump). The working device refers to a device such as a shovel. The automatic speed control process of the working device motor is that the main controller controls the speed of the working device motor according to the operating action of the working device.

[0028] Figure 2 The following is a flow chart of a method for dynamic performance matching of a pure electric motor grader provided by an embodiment of the present invention, which realizes dynamic performance matching based on automatic speed control of the motor of the working device. Figure 2 The execution subject may be a pure electric motor grader dynamic performance matching system. The pure electric motor grader dynamic performance matching method provided in the embodiment of the present invention is executed by a computer device, and accordingly, the pure electric motor grader dynamic performance matching system runs in the computer device. According to different requirements, the order of the steps in the flowchart can be changed, and some can be omitted.

[0029] like Figure 2 As shown, the method specifically includes the following steps.

[0030] S101, obtaining the hydraulic oil pressure in the hydraulic circuit.

[0031] like Figure 4 As shown, in an optional embodiment, the hydraulic oil pressure in the hydraulic circuit is detected by a pressure sensor.

[0032] like Figure 5As shown, in an optional embodiment, since the hydraulic oil pressure in the hydraulic circuit varies greatly, is highly random, and needs to rely on sensors, in order to meet engineering needs and for the purpose of simplification, the current pressure signal may not be detected, and the pressure may be taken as a typical value, such as the hydraulic oil pressure in the hydraulic circuit. When configuring the hydraulic oil pressure in the reference hydraulic circuit, the fixed value is set as follows: no pressure sensor is set, and the pressure value is set to 18 Mpa in the algorithm (software). 18 Mpa is the hydraulic oil pressure value under typical working conditions of a grader (the hydraulic oil pressure value under typical working conditions of different graders is different). This embodiment uses 18 Mpa as an example.

[0033] S102, detecting the driver's operating action, and calculating the required total flow rate of hydraulic oil according to the driver's operating action.

[0034] The driver's operating actions include blade lifting, tilting, angle adjustment, side exit, etc. The total flow of the compound action of the driver performing N actions is the total flow of hydraulic oil required. The total flow of hydraulic oil required is obtained by adding up the flow of hydraulic oil of each action. The hydraulic oil flow can be measured by a flow sensor.

[0035] S103, based on the hydraulic oil pressure in the hydraulic circuit and the required total flow rate of the hydraulic transmission medium, find the motor speed corresponding to the maximum working device driving total efficiency through a cyclic optimization algorithm, and record it as the optimal motor speed.

[0036] S103.1, configure the minimum motor speed, maximum motor speed and step size.

[0037] S103.2, between the minimum motor speed and the maximum motor speed, select a motor speed value at every other step, and record it as the target motor speed.

[0038] S103.3, calculate the motor working torque based on the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and record it as the target motor working torque.

[0039] Target motor working torque = (hydraulic oil pressure in the hydraulic circuit * required total flow of hydraulic transmission medium) / target motor speed.

[0040] S103.4, searching the motor efficiency corresponding to each set of target motor speed and target motor working torque in the motor efficiency MAP diagram, and recording them as target motor efficiency.

[0041] S103.5, using the target motor speed as the target hydraulic pump speed.

[0042] S103.6, calculate the hydraulic pump working displacement based on the target hydraulic pump speed and the required total flow rate of the hydraulic transmission medium.

[0043] S103.7, search the hydraulic pump efficiency table for each set of target hydraulic pump speed and hydraulic pump working displacement, and record it as the target hydraulic pump efficiency.

[0044] S103.8, calculating the total driving efficiency of the working device according to the target motor efficiency and the target hydraulic pump efficiency, and recording it as the target total driving efficiency of the working device.

[0045] Target drive system total efficiency = target motor efficiency * target hydraulic pump efficiency.

[0046] S103.9, finding the maximum working device driving total efficiency among all target working device driving total efficiencies, and selecting the target motor speed corresponding to the maximum working device driving total efficiency as the optimal motor speed.

[0047] S104, generating an actual execution speed instruction based on the optimal motor speed, and sending it to the motor controller of the working device.

[0048] The main controller executes the above steps and sends the execution speed command to the motor controller of the working device. Figure 3 is a flow chart of a specific embodiment of the automatic speed control of the working device motor. In this specific embodiment, the motor efficiency generated by all motor speeds is and LS pump efficiency Simulate and calculate, and then find the optimal , here The product of the efficiency of the working device motor and the LS pump is Since the speed is a continuous value, in order to reduce the amount of calculation, its range can be defined and discretized, which has little effect on the result.

[0049] Working device motor speed It is a variable that needs to be traversed in the optimization algorithm. To simplify the calculation, the speed can be changed from the minimum To the maximum The range takes a value at every fixed step length, for example, the step length is 100rpm, so is a discrete array The minimum speed can be determined by the flow requirement. Calculated with the maximum pump displacement. Flow requirements The flow demand can be calculated by detecting the driver's operation and the corresponding hydraulic cylinder parameters of the corresponding action. For example, if the driver performs a compound action of N actions, the flow demand is .

[0050] Working device motor torque By formula , calculated. The efficiency of the working device motor Its working speed and working torque Related. According to and , find the motor efficiency in the motor efficiency map LS pump operating speed , LS pump working displacement It is a self-adjusting quantity according to flow demand and load pressure. Calculate. LS pump working pressure Measured by pressure sensor, due to the efficiency of LS pump and its working displacement , Working speed and work pressure The efficiency of the LS pump can be calculated by The total efficiency of the working device drive is .

[0051] An embodiment of a method for dynamic performance matching of a pure electric motor grader is described in detail above. Based on the method for dynamic performance matching of a pure electric motor grader described in the above embodiment, an embodiment of the present invention further provides a pure electric motor grader dynamic performance matching system corresponding to the method.

[0052] Figure 6 is a schematic block diagram of a pure electric motor grader dynamic performance matching system provided by an embodiment of the present invention. In this embodiment, the pure electric motor grader dynamic performance matching system 200 can be divided into a plurality of functional modules according to the functions it performs, such as Figure 6 As shown. The functional modules may include: a hydraulic oil pressure acquisition module, a hydraulic oil total flow calculation module, an optimal motor speed acquisition module, and an instruction issuing module. The module referred to in the present invention refers to a series of computer program segments that can be executed by at least one processor and can complete fixed functions, which are stored in a memory.

[0053] Hydraulic oil pressure acquisition module: obtains the hydraulic oil pressure in the hydraulic circuit; Hydraulic oil total flow calculation module: detects the driver's operating actions and calculates the required total hydraulic oil flow according to the driver's operating actions; Optimal motor speed acquisition module: Based on the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, the motor speed corresponding to the maximum working device driving efficiency is found through a cyclic optimization algorithm, which is recorded as the optimal motor speed; Instruction issuing module: generates the actual execution speed instruction from the optimal motor speed and sends it to the motor controller of the working device.

[0054] In an optional implementation, the optimal motor speed acquisition module finds the motor speed corresponding to the maximum working device driving total efficiency through a cyclic optimization algorithm, specifically including: Configure minimum motor speed, maximum motor speed and step size; Between the minimum motor speed and the maximum motor speed, a motor speed value is selected every other step and recorded as the target motor speed; The motor working torque is calculated according to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and is recorded as the target motor working torque; Find the motor efficiency corresponding to each set of target motor speed and target motor working torque in the motor efficiency MAP diagram, and record it as the target motor efficiency; The target motor speed is used as the target hydraulic pump speed; Calculate the hydraulic pump working displacement according to the target hydraulic pump speed and the required total flow of hydraulic transmission medium; Find the hydraulic pump efficiency corresponding to each set of target hydraulic pump speed and hydraulic pump working displacement in the hydraulic pump efficiency table, and record it as the target hydraulic pump efficiency; Calculate the total efficiency of the working device drive according to the target motor efficiency and the target hydraulic pump efficiency, and record it as the target total efficiency of the working device drive; The maximum working device driving total efficiency is found among all target working device driving total efficiencies, and the target motor speed corresponding to the maximum working device driving total efficiency is selected and recorded as the optimal motor speed.

[0055] In an optional embodiment, the motor working torque is calculated according to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and is recorded as the target motor working torque, which is specifically calculated by the following formula: Target motor working torque = (hydraulic oil pressure in the hydraulic circuit * required total flow of hydraulic transmission medium) / target motor speed.

[0056] In an optional implementation, the total efficiency of the drive system is calculated according to the target motor efficiency and the target hydraulic pump efficiency, and is recorded as the target total efficiency of the drive system, which is specifically calculated by the following formula: Target drive system total efficiency = target motor efficiency * target hydraulic pump efficiency.

[0057] In an optional embodiment, the hydraulic oil pressure acquisition module acquires the hydraulic oil pressure in the hydraulic circuit, specifically including: configuring the hydraulic oil pressure in the reference hydraulic circuit, and storing the hydraulic oil pressure in the reference hydraulic circuit in a storage area; and retrieving the hydraulic oil pressure in the reference hydraulic circuit from the storage area.

[0058] The pure electric grader dynamic performance matching system of the present embodiment is used to implement the aforementioned pure electric grader dynamic performance matching method. Therefore, the specific implementation method of the system can be seen in the implementation method part of the operation and maintenance method based on time series data trend prediction in the previous text. Therefore, its specific implementation method can refer to the description of the corresponding embodiments of each part, which will not be elaborated here.

[0059] In addition, since the pure electric motor grader dynamic performance matching system of the present embodiment is used to implement the aforementioned pure electric motor grader dynamic performance matching method, its function corresponds to that of the aforementioned method and will not be described in detail here.

Claims

1. A method for matching the dynamic performance of a pure electric grader, characterized in that: The specific steps include: Obtain the hydraulic oil pressure in the hydraulic circuit; Detect the driver's operating actions and calculate the required total flow of hydraulic oil according to the driver's operating actions; Based on the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, the motor speed corresponding to the maximum total efficiency of the working device drive is found through a cyclic optimization algorithm, which is recorded as the optimal motor speed; The optimal motor speed is converted into the actual execution speed command and sent to the motor controller of the working device.

2. The method for matching the dynamic performance of a pure electric motor grader according to claim 1, characterized in that: The motor speed corresponding to the maximum working device driving total efficiency is found through a cyclic optimization algorithm, specifically including: Configure minimum motor speed, maximum motor speed and step size; Between the minimum motor speed and the maximum motor speed, a motor speed value is selected every other step and recorded as the target motor speed; The motor working torque is calculated according to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and is recorded as the target motor working torque; Find the motor efficiency corresponding to each set of target motor speed and target motor working torque in the motor efficiency MAP diagram, and record it as the target motor efficiency; The target motor speed is used as the target hydraulic pump speed; Calculate the hydraulic pump working displacement according to the target hydraulic pump speed and the required total flow of hydraulic transmission medium; Find the hydraulic pump efficiency corresponding to each set of target hydraulic pump speed and hydraulic pump working displacement in the hydraulic pump efficiency table, and record it as the target hydraulic pump efficiency; Calculate the total efficiency of the working device drive according to the target motor efficiency and the target hydraulic pump efficiency, and record it as the target total efficiency of the working device drive; The maximum working device driving total efficiency is found among all target working device driving total efficiencies, and the target motor speed corresponding to the maximum working device driving total efficiency is selected and recorded as the optimal motor speed.

3. The method for matching the dynamic performance of a pure electric motor grader according to claim 2, characterized in that: According to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, the motor working torque is calculated and recorded as the target motor working torque, which is specifically calculated by the following formula: Target motor working torque = (hydraulic oil pressure in the hydraulic circuit * required total flow of hydraulic transmission medium) / target motor speed.

4. The method for matching the dynamic performance of a pure electric motor grader according to claim 2, characterized in that: The total efficiency of the drive system is calculated based on the target motor efficiency and the target hydraulic pump efficiency, which is recorded as the target total efficiency of the drive system. Specifically, it is calculated using the following formula: Target drive system total efficiency = target motor efficiency * target hydraulic pump efficiency.

5. A dynamic performance matching system for a pure electric grader, characterized in that: include, Hydraulic oil pressure acquisition module: obtains the hydraulic oil pressure in the hydraulic circuit; Hydraulic oil total flow calculation module: detects the driver's operating actions and calculates the required total hydraulic oil flow according to the driver's operating actions; Optimal motor speed acquisition module: Based on the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, the motor speed corresponding to the maximum working device driving efficiency is found through a cyclic optimization algorithm, which is recorded as the optimal motor speed; Instruction issuing module: generates the actual execution speed instruction from the optimal motor speed and sends it to the motor controller of the working device.

6. The pure electric grader dynamic performance matching system according to claim 5, characterized in that: The optimal motor speed acquisition module finds the motor speed corresponding to the maximum working device driving total efficiency through a cyclic optimization algorithm, specifically including: Configure minimum motor speed, maximum motor speed and step size; Between the minimum motor speed and the maximum motor speed, a motor speed value is selected every other step and recorded as the target motor speed; The motor working torque is calculated according to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, and is recorded as the target motor working torque; Find the motor efficiency corresponding to each set of target motor speed and target motor working torque in the motor efficiency MAP diagram, and record it as the target motor efficiency; The target motor speed is used as the target hydraulic pump speed; Calculate the hydraulic pump working displacement according to the target hydraulic pump speed and the required total flow of hydraulic transmission medium; Find the hydraulic pump efficiency corresponding to each set of target hydraulic pump speed and hydraulic pump working displacement in the hydraulic pump efficiency table, and record it as the target hydraulic pump efficiency; Calculate the total efficiency of the working device drive according to the target motor efficiency and the target hydraulic pump efficiency, and record it as the target total efficiency of the working device drive; The maximum working device driving total efficiency is found among all target working device driving total efficiencies, and the target motor speed corresponding to the maximum working device driving total efficiency is selected and recorded as the optimal motor speed.

7. The pure electric grader dynamic performance matching system according to claim 6, characterized in that: According to the target motor speed, the hydraulic oil pressure in the hydraulic circuit and the required total flow of the hydraulic transmission medium, the motor working torque is calculated and recorded as the target motor working torque, which is specifically calculated by the following formula: Target motor working torque = (hydraulic oil pressure in the hydraulic circuit * required total flow of hydraulic transmission medium) / target motor speed.

8. The pure electric grader dynamic performance matching system according to claim 6, characterized in that: The total efficiency of the drive system is calculated based on the target motor efficiency and the target hydraulic pump efficiency, which is recorded as the target total efficiency of the drive system. Specifically, it is calculated using the following formula: Target drive system total efficiency = target motor efficiency * target hydraulic pump efficiency.

Images