Method and device for controlling the speed of an electric motor

Abstract

The application relates to the automatic control field and provides a motor rotating speed control method and device, the method comprises the following steps: acquiring a pilot pressure and a load pressure of a working machine, determining a maximum power of a motor; based on a first mapping relationship, determining a motor theoretical rotating speed corresponding to the pilot pressure under a current working action; based on a second mapping relationship and the maximum power of the motor, determining a maximum rotating speed of the motor corresponding to the load pressure; comparing the motor theoretical rotating speed with the maximum rotating speed of the motor, and determining the motor rotating speed of the working machine based on the comparison result. The pilot pressure is used to determine the motor theoretical rotating speed through the first mapping relationship, the maximum power of the motor is used to determine the maximum rotating speed of the motor corresponding to the load pressure through the second mapping relationship, finally, the motor theoretical rotating speed is compared with the maximum rotating speed of the motor, and the motor rotating speed of the working machine is determined, the working machine can work at the corresponding motor rotating speed according to different working actions, and the problem that the energy consumption of the working machine is high during working is solved.

Description

Technical Field

[0001] The present invention relates to the field of automatic control technology, and in particular to a method and device for controlling the speed of a motor. Background Art

[0002] Currently, when a hydraulic system is used to control a working machine to perform a working action, a motor is generally used as a power source, and the motor is controlled to drive the hydraulic pump to operate, thereby achieving control of the working action.

[0003] Although the traditional motor control method can meet the operator's needs for motion control of the operating machinery, it is prone to the problem of hydraulic pump output flow overflow, resulting in high energy consumption of the operating machinery during operation. Summary of the Invention

[0004] The present invention provides a method and device for controlling the speed of a motor, which are used to solve the defect in the conventional motor control method in the prior art that the output flow of the hydraulic pump is easily overflowed, resulting in high energy consumption of the operating machine during operation.

[0005] In a first aspect, the present invention provides a method for controlling motor speed, which is applied to a working machine and includes:

[0006] Obtaining a pilot pressure and a load pressure of an operating machine, and determining a maximum power of a motor of the operating machine;

[0007] Determining the theoretical motor speed corresponding to the pilot pressure under the current operation based on a first mapping relationship; wherein the first mapping relationship is used to represent the corresponding relationship between the pilot pressure and the theoretical motor speed under each operation;

[0008] Determining the maximum speed of the motor corresponding to the load pressure based on a second mapping relationship and the maximum power of the motor; wherein the second mapping relationship is used to represent the corresponding relationship between the load pressure and the maximum speed of the motor at the maximum power of each motor;

[0009] The theoretical motor speed is compared with the maximum motor speed, and the motor speed of the working machine is determined based on a result of the comparison.

[0010] The motor speed control method provided by the present invention can directly determine the theoretical motor speed and the maximum motor speed corresponding to the load pressure under the maximum power of the motor through the first mapping relationship and the second mapping relationship respectively, compare the theoretical motor speed with the maximum motor speed to determine the motor speed of the operating machinery, and can control the operating machinery to work at the corresponding motor speed according to different operating actions, thereby reducing the probability of overflow of the hydraulic pump output flow, and thereby reducing the energy consumption of the operating machinery during the operation process.

[0011] According to the motor speed control method provided by the present invention, determining the maximum power of the motor of the working machine includes:

[0012] Obtaining a load pressure change rate of the operating machine;

[0013] The load pressure change rate is compared with a preset change rate threshold, and the maximum power of the motor of the working machine is determined according to the comparison result.

[0014] According to the motor speed control method provided by the present invention, the load pressure change rate is compared with a preset change rate threshold, and the maximum power of the motor of the working machine is determined according to the comparison result, including:

[0015] If the load pressure change rate does not exceed the preset change rate threshold, the first power value is used as the maximum power of the motor of the working machine;

[0016] If the load pressure change rate exceeds the preset change rate threshold and the duration exceeds the preset duration threshold, the second power value is used as the maximum power of the motor of the working machine.

[0017] According to the motor speed control method provided by the present invention, if the load pressure change rate exceeds the preset change rate threshold and the duration exceeds the preset duration threshold, then the second power value is used as the maximum power of the motor of the working machine, including:

[0018] If the load pressure change rate exceeds the preset change rate threshold and the duration exceeds the preset duration threshold, determining the operating condition of the operating machine according to the pilot pressure;

[0019] determining whether the operating machine is performing a specific operating action based on the operating condition;

[0020] If it is determined that the working machine is performing a specific working action, the motor power value corresponding to the specific working action is used as the second power value;

[0021] The second power value is used as the maximum power of the motor of the working machine.

[0022] In the motor speed control method provided by the present invention, the corresponding power value can be targeted as the maximum power of the motor according to the actual situation of the load pressure change rate, thereby improving the accuracy and reliability of the ultimately determined maximum power of the motor.

[0023] According to the motor speed control method provided by the present invention, when the current operation action is a compound action, determining the motor theoretical speed corresponding to the pilot pressure under the current operation action based on the first mapping relationship includes:

[0024] Based on the first mapping relationship, respectively determining the theoretical rotational speed corresponding to the pilot pressure in each working action in the compound action;

[0025] The theoretical partial speeds are summed, and the summation result is used as the theoretical speed of the motor.

[0026] In the motor speed control method provided by the present invention, for the case where the current working action is a compound action, the theoretical motor speed can be determined by decomposing the compound action and summing the speeds. Therefore, this method can be applied not only to the motor speed control process of a single working action, but also to the motor speed control process of a compound working action, and has a wider scope of application.

[0027] According to the motor speed control method provided by the present invention, the motor theoretical speed is compared with the maximum speed of the motor, and the motor speed of the working machine is determined based on the comparison result, including:

[0028] If the theoretical speed of the motor is less than the maximum speed of the motor, the theoretical speed of the motor is used as the motor speed of the working machine;

[0029] If the theoretical speed of the motor is greater than or equal to the maximum speed of the motor, the maximum speed of the motor is used as the motor speed of the working machine.

[0030] In the motor speed control method provided by the present invention, when determining the motor speed of an operating machine, the finally determined motor speed is controlled below the maximum speed of the motor, thereby ensuring the safe operation of the operating machine.

[0031] In a second aspect, the present invention further provides a device for controlling the speed of a motor, the device comprising:

[0032] an acquisition module, configured to acquire a pilot pressure and a load pressure of the operating machine and determine a maximum power of a motor of the operating machine;

[0033] A first processing module is configured to determine, based on a first mapping relationship, a theoretical motor speed corresponding to the pilot pressure in a current operation; wherein the first mapping relationship is configured to represent a correspondence between the pilot pressure and the theoretical motor speed in each operation;

[0034] a second processing module, configured to determine the maximum motor speed corresponding to the load pressure based on a second mapping relationship and the maximum motor power; wherein the second mapping relationship is used to represent the corresponding relationship between the load pressure and the maximum motor speed at the maximum power of each motor;

[0035] The third processing module is configured to compare the theoretical speed of the motor with the maximum speed of the motor, and determine the speed of the motor of the working machine based on a result of the comparison.

[0036] The motor speed control device provided by the present invention can directly determine the theoretical motor speed and the maximum motor speed corresponding to the load pressure under the maximum power of the motor through the first mapping relationship and the second mapping relationship respectively by using the first processing module and the second processing module based on the acquisition module, and compare the theoretical motor speed with the maximum motor speed through the third processing module to determine the motor speed of the operating machinery. It can control the operating machinery to work at the corresponding motor speed according to different operating actions, reduce the probability of overflow of the hydraulic pump output flow, and thereby reduce the energy consumption of the operating machinery during the operation process.

[0037] In a third aspect, the present invention further provides a method for controlling a hydraulic system, the method comprising:

[0038] Determining the motor speed of the working machine by any of the above-mentioned motor speed control methods;

[0039] The output flow of the hydraulic pump in the hydraulic system is controlled according to the motor speed.

[0040] The control method of the hydraulic system provided by the present invention can determine the motor speed of the operating machinery based on the above-mentioned motor speed control method, and then control the output flow of the hydraulic pump in the hydraulic system through the motor speed. By accurately controlling the motor speed, the output flow of the hydraulic pump can be precisely regulated, thereby reducing the probability of overflow of the hydraulic pump output flow, improving the control accuracy of the hydraulic system, and reducing the working energy consumption of the operating machinery.

[0041] In a fourth aspect, the present invention further provides a hydraulic system employing the aforementioned control method for a hydraulic system. By employing the aforementioned control method for a hydraulic system, the hydraulic system can reduce the probability of hydraulic pump output flow overflow by accurately controlling the motor speed, thereby improving the operational reliability of the hydraulic system.

[0042] In a fifth aspect, the present invention further provides an operating machine comprising the hydraulic system. By using the hydraulic system, the operating machine can effectively control the output flow of the hydraulic pump through the motor speed, thereby reducing energy consumption during operation.

[0043] The motor speed control method and device provided by the present invention directly determine the theoretical speed of the motor using a first mapping relationship through pilot pressure, and determine the maximum speed of the motor corresponding to the load pressure under the maximum power of the motor through a second mapping relationship. Finally, the theoretical speed of the motor is compared with the maximum speed of the motor to determine the motor speed of the operating machinery. This can control the operating machinery to operate at the corresponding motor speed according to different operating actions, reduce the probability of overflow of the hydraulic pump output flow, and effectively reduce the energy consumption of the operating machinery during the operation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 This is one of the flow charts of the motor speed control method provided by the present invention;

[0046] Figure 2 It is a flowchart of the process of determining the maximum speed of the motor;

[0047] Figure 3 This is the second flow chart of the motor speed control method provided by the present invention;

[0048] Figure 4 It is a structural schematic diagram of the motor speed control device provided by the present invention;

[0049] Figure 5 It is a flow chart of the control method of the hydraulic system;

[0050] Figure 6 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0052] The following combination Figures 1 to 6The present invention describes a motor speed control method, a motor speed control device, a hydraulic system control method, a hydraulic system, a working machine, and an electronic device based on the motor speed control method, provided in embodiments of the present invention.

[0053] Figure 1 A method for controlling the motor speed provided by an embodiment of the present invention is shown. The method is applied to a working machine and includes:

[0054] Step 101: Obtain the pilot pressure and load pressure of the operating machine, and determine the maximum power of the motor of the current operating machine;

[0055] Step 102: Determine the theoretical motor speed corresponding to the pilot pressure under the current operation based on a first mapping relationship; wherein the first mapping relationship is used to represent the corresponding relationship between the pilot pressure and the theoretical motor speed under each operation;

[0056] Step 103: Determine the maximum motor speed corresponding to the load pressure based on the second mapping relationship and the maximum motor power; wherein the second mapping relationship is used to represent the corresponding relationship between the load pressure and the maximum motor speed at the maximum power of each motor;

[0057] Step 104: Compare the theoretical motor speed with the maximum motor speed, and determine the motor speed of the working machine based on the comparison result.

[0058] In this embodiment, the pilot pressure of the operating machine can be the pilot pressure of each handle and pedal on the operating machine. The operator's pushing amplitude of each handle and pedal corresponds to different pilot pressures. Therefore, the size of the pilot pressure can indicate the operator's driving intention for the operating machine.

[0059] The driving intention mentioned above mainly refers to the control of the speed of each working action, and the speed of the action is related to the output flow of the hydraulic pump. By controlling the motor speed, the output flow of the hydraulic pump can be controlled, thereby avoiding the problem of excess flow overflow of the hydraulic pump.

[0060] In this embodiment, the load pressure refers to the pressure in the working oil circuit of the hydraulic system of the working machine, and the output power of the motor can be obtained by multiplying the load pressure by the motor speed.

[0061] In this embodiment, the maximum motor power primarily refers to the maximum power allowed to be output by the motor under the current operating conditions. In this embodiment, the motor is the motor that drives the hydraulic pump on the working machine. Therefore, the output flow of the hydraulic pump can be controlled by controlling the motor speed, ensuring that the output flow of the hydraulic pump is as close to the required flow as possible, thereby achieving energy conservation.

[0062] It should be noted that the first mapping relationship in this embodiment can be obtained by calibrating the pilot pressure and the motor speed for different operation actions. Specifically, the pilot pressure-motor speed is calibrated according to the volume of the oil cylinder inlet cavity, the pump displacement and the load pressure under each action, so as to obtain the motor speed corresponding to different pilot pressures under each single action.

[0063] The size of the pilot pressure is positively correlated with the pushing angle of the operating handle, so that the size of the pilot pressure can indicate the operation intention of the operator, that is, the requirement for the speed of each action, and the speed of the action is positively correlated with the output flow of the hydraulic pump, so that the motor speed can be used to control the size of the output flow of the hydraulic pump.

[0064] The second mapping relationship in this embodiment can be obtained by calibrating the load pressure and the maximum motor speed under the condition that the maximum motor power and the load pressure are determined, and specifically, the maximum motor power corresponding to the motor constant power external characteristic curve can be plotted according to the calibration result, the horizontal axis of the curve is the load pressure, and the vertical axis is the maximum motor speed.

[0065] Referring to FIG. 4, Figure 2 The process of obtaining the maximum motor speed is as follows:

[0066] Step 201: input the load pressure;

[0067] Step 202: input the maximum motor power;

[0068] Step 203: calculate the maximum motor speed n max Specifically, the maximum motor speed is equal to the power threshold (i.e. the maximum motor power) divided by the product of the load pressure and the displacement, wherein the displacement refers to the displacement of the hydraulic pump, and the displacement of the hydraulic pump is set to be constant in the calculation process of this embodiment;

[0069] Step 204: output the maximum motor speed.

[0070] In actual application, the finally determined maximum motor speed can be slightly lower than the speed value determined by the motor constant power external characteristic curve, so that a more optimal energy-saving effect can be achieved.

[0071] In an exemplary embodiment, the process of determining the maximum motor power of the working machine can specifically include:

[0072] First, the load pressure change rate of the working machine is obtained;

[0073] Then, the load pressure change rate is compared with the preset change rate threshold, and the maximum motor power of the working machine is determined according to the comparison result.

[0074] It can be understood that the load pressure change rate refers to the change value of the load pressure per unit time. If the load pressure increases or decreases suddenly, that is, the load pressure change rate exceeds a certain change rate threshold, it means that the operating conditions of the operating machinery have changed, and it is necessary to match the corresponding motor speed in a timely and accurate manner to ensure that while there is sufficient flow supply to the working device of the operating machinery, flow overflow is avoided as much as possible, thereby achieving energy-saving effects.

[0075] Furthermore, the process of comparing the load pressure change rate with a preset change rate threshold and determining the maximum power of the motor of the working machine according to the comparison result may specifically include:

[0076] On the one hand, if the load pressure change rate does not exceed the preset change rate threshold, the first power value is used as the maximum power of the motor of the working machine.

[0077] If the load pressure change rate does not exceed the preset change rate threshold, it means that the operating condition of the operating machine is normal at this time. At this time, the maximum power value corresponding to the current operating action (i.e., the first power value) is used as the maximum power of the motor of the operating machine to meet actual needs.

[0078] On the other hand, if the load pressure change rate exceeds the preset change rate threshold and the duration exceeds the preset duration threshold, the second power value is used as the maximum power of the motor of the working machine.

[0079] In an exemplary embodiment, if the load pressure change rate exceeds a preset change rate threshold and the duration exceeds a preset duration threshold, the process of using the second power value as the maximum power of the motor of the working machine may specifically include:

[0080] First, if the load pressure change rate exceeds a preset change rate threshold and the duration exceeds a preset duration threshold, the operating condition of the operating machine is determined based on the pilot pressure;

[0081] Then, based on the working conditions, it is determined whether the working machine is performing a specific working action;

[0082] Afterwards, if it is determined that the operating machine is performing a specific operating action, the motor power value corresponding to the specific operating action is used as the second power value;

[0083] Finally, the second power value is used as the maximum power of the motor of the working machine.

[0084] It is understandable that the specific working action in this embodiment may be a boom lowering action, a hard object digging action, or other working actions that can cause a sudden change in load pressure.

[0085] If the load pressure change rate exceeds the preset change rate threshold and the duration exceeds the preset duration threshold, it means that the operating condition of the operating machine has changed. For example, the pilot pressure can be used to judge that the operating machine is excavating a hard object, and the operating machine enters a large-load excavation state. In this state, a second power value higher than the first power value can be used as the maximum power of the motor of the operating machine, that is, the maximum power of the motor is increased to correspondingly increase the maximum speed of the motor, thereby ensuring that under large load conditions, the output flow of the hydraulic pump meets the operating requirements of the working device, thereby achieving the effect of improving the operating efficiency of the operating machine.

[0086] For example, by judging through the pilot pressure that the operating machine is performing the action of lowering the boom, due to the effect of its own gravitational potential energy and the design of the hydraulic oil circuit such as boom regeneration, the action speed of the working device can meet the actual operating requirements. At this time, the second power value lower than the first power value can be used as the maximum power of the motor of the operating machine, that is, the maximum power of the motor is reduced to reduce the maximum speed of the motor accordingly, thereby ensuring lower energy consumption during the operating action and achieving energy-saving effects.

[0087] In an exemplary embodiment, when the current operation action is a compound action, the process of determining the motor theoretical speed corresponding to the pilot pressure under the current operation action based on the first mapping relationship may specifically include:

[0088] Based on the first mapping relationship, respectively determine the theoretical partial speed corresponding to the pilot pressure under each working action in the compound action;

[0089] Sum up the theoretical speed components and use the sum as the theoretical speed of the motor.

[0090] In actual application, it is often encountered that the operating machinery performs complex operating actions. At this time, the complex action can be disassembled into multiple single actions, and the theoretical motor speed (i.e., theoretical partial speed) corresponding to the pilot pressure under each single action can be determined separately. Then, the theoretical partial speeds of each single action are summed to obtain the theoretical motor speed corresponding to the entire complex action.

[0091] In an exemplary embodiment, the process of comparing the theoretical motor speed with the maximum motor speed and determining the motor speed of the working machine based on the comparison result may specifically include:

[0092] If the motor theoretical speed is less than the motor maximum speed, the motor theoretical speed shall be used as the motor speed of the operating machine;

[0093] If the theoretical motor speed is greater than or equal to the maximum motor speed, the maximum motor speed is used as the motor speed of the operating machine.

[0094] It can be understood that in order to reduce the phenomenon of hydraulic pump output flow overflow under various working actions, this embodiment first determines the maximum speed of the motor corresponding to each working action, and controls the motor speed finally used for motor control to be no higher than the maximum speed of the motor. On the premise of ensuring the normal execution of the working action, the motor speed is reduced as much as possible, thereby effectively reducing the energy consumption of the working machinery and avoiding the problem of energy waste caused by the hydraulic pump output flow being higher than the design required flow.

[0095] See attached Figure 3 , the entire motor speed control method can be achieved through the following process:

[0096] Step 301: When an operator operates a handle on a working machine to perform a single action or a compound action, a corresponding pilot pressure is obtained;

[0097] Step 302: Based on the cylinder volume (i.e., the volume of the oil inlet chamber of the cylinder), the pump displacement, and the load pressure, the motor theoretical speed is obtained through calculation and calibration;

[0098] Step 303: Obtaining the load pressure of the operating machine;

[0099] Step 304: Determine whether the load pressure change rate exceeds a preset change rate threshold;

[0100] Step 305: If the load pressure change rate exceeds a preset change rate threshold, the pilot pressure is further used to determine whether a specific operation is currently being performed. In this embodiment, the specific operation can be an operation that causes a sudden change in load pressure, such as a boom lowering operation or a hard object excavation operation.

[0101] Step 306: If a certain specific operation is being performed, the motor power threshold value P2 (ie, the second power) is input into the constant power module, thereby outputting the maximum motor speed n max ;

[0102] Step 307: If the load pressure change rate does not exceed the preset change rate threshold, or if it is determined that certain specific operation actions are not performed, the motor power threshold P1 is input (i.e., the first power) into the constant power module, thereby outputting the maximum motor speed n max ;

[0103] Step 308: Determine whether the theoretical motor speed exceeds the maximum motor speed n under constant power. max ;

[0104] Step 309: If the theoretical speed of the motor does not exceed the maximum speed of the motor n max , then the theoretical speed of the motor is output as the motor speed of the operating machine;

[0105] Step 310: If the theoretical speed of the motor exceeds the maximum speed n of the motormax , then the maximum speed of the output motor is n max , as the motor speed of the operating machinery.

[0106] It can be seen that the motor speed control method provided by the embodiment of the present invention can determine the theoretical speed of the motor based on the pilot pressure under the current working action and the first mapping relationship, and determine the maximum speed of the motor based on the maximum power of the motor, the load pressure and the second mapping relationship. When the theoretical speed of the motor does not exceed the maximum speed of the motor, the theoretical speed of the motor is used as the motor speed of the working machine. When the theoretical speed of the motor exceeds the maximum speed of the motor, the maximum speed of the motor is used as the motor speed of the working machine. Therefore, according to different working actions, the working machine can be controlled to operate within the corresponding maximum speed of the motor, and the output flow of the hydraulic pump can be made close to the required flow, thereby achieving the effect of reducing energy consumption.

[0107] The motor speed control device provided by the present invention is described below. The motor speed control device described below and the motor speed control method described above can be referenced to each other.

[0108] Figure 4 The present invention provides a motor speed control device, which includes:

[0109] An acquisition module 401 is used to acquire the pilot pressure and load pressure of the operating machine and determine the maximum power of the motor of the operating machine;

[0110] The first processing module 402 is configured to determine the theoretical motor speed corresponding to the pilot pressure under the current operation based on a first mapping relationship, wherein the first mapping relationship is used to represent the corresponding relationship between the pilot pressure and the theoretical motor speed under each operation;

[0111] The second processing module 403 is configured to determine the maximum motor speed corresponding to the load pressure based on the second mapping relationship and the maximum motor power; wherein the second mapping relationship is used to represent the corresponding relationship between the load pressure and the maximum motor speed at the maximum power of each motor;

[0112] The third processing module 404 is configured to compare the theoretical speed of the motor with the maximum speed of the motor, and determine the motor speed of the working machine based on the comparison result.

[0113] In an exemplary embodiment, the acquisition module 401 may be specifically used to: acquire the load pressure change rate of the operating machine; compare the load pressure change rate with a preset change rate threshold, and determine the maximum motor power of the operating machine based on the comparison result.

[0114] Furthermore, the acquisition module 401 may specifically compare the load pressure change rate with a preset change rate threshold value and determine the maximum motor power of the operating machine according to the comparison result in the following manner:

[0115] If the load pressure change rate does not exceed a preset change rate threshold, the first power value is used as the maximum power of the motor of the operating machine;

[0116] If the load pressure change rate exceeds a preset change rate threshold and the duration exceeds a preset duration threshold, the second power value is used as the maximum power of the motor of the working machine.

[0117] Furthermore, the acquisition module 401 may specifically implement the following method to use the second power value as the maximum power of the motor of the operating machine when the load pressure change rate exceeds a preset change rate threshold and the duration exceeds a preset duration threshold:

[0118] If the load pressure change rate exceeds a preset change rate threshold and the duration exceeds a preset duration threshold, the operating condition of the operating machine is determined based on the pilot pressure;

[0119] Determine whether the operating machine is performing a specific operating action based on the operating conditions;

[0120] If it is determined that the operating machine is performing a specific operating action, the motor power value corresponding to the specific operating action is used as the second power value;

[0121] The second power value is used as the maximum power of the motor of the working machine.

[0122] In an exemplary embodiment, when the current working action is a compound action, the above-mentioned first processing module 402 can be specifically used to: based on the first mapping relationship, determine the theoretical partial speeds corresponding to the pilot pressure under each working action in the compound action; sum up each theoretical partial speed, and use the summed result as the theoretical speed of the motor.

[0123] In an exemplary embodiment, the above-mentioned third processing module 404 can be specifically used to: if the theoretical speed of the motor is less than the maximum speed of the motor, then the theoretical speed of the motor is used as the motor speed of the operating machine; if the theoretical speed of the motor is greater than or equal to the maximum speed of the motor, then the maximum speed of the motor is used as the motor speed of the operating machine.

[0124] It can be seen that the motor speed control device provided in the embodiment of the present invention can obtain the operator's operating intention through the pilot pressure, and directly control the motor speed according to the operator's operating intention, making the control process more efficient and lowering energy consumption.

[0125] Figure 5 A control method for a hydraulic system provided by an embodiment of the present invention is shown, the method comprising:

[0126] Step 501: Determine the motor speed of the operating machine using the motor speed control method described above;

[0127] Step 502: Control the output flow of the hydraulic pump in the hydraulic system according to the motor speed.

[0128] In this embodiment, the motor is connected to the hydraulic pump in the hydraulic system. By controlling the speed of the motor, the output flow of the hydraulic pump can be further controlled, thereby achieving effective control of the output flow of the hydraulic pump in the hydraulic system.

[0129] In this embodiment, the hydraulic pump can adopt a fixed-displacement pump. When the pump displacement is constant, the motor speed is controlled, and then the output flow of the pump is controlled, so that the output flow of the pump is closer to the required flow, avoiding the problem of excess flow overflow caused by the deviation between the output flow of the pump and the required flow of the actual cylinder, thereby causing increased energy consumption.

[0130] In addition, an embodiment of the present invention further provides a hydraulic system, which uses the control method of the hydraulic system described above.

[0131] In addition, an embodiment of the present invention further provides an operating machine, which includes the above-mentioned hydraulic system.

[0132] In this embodiment, the operating machine can be an excavator, specifically an electric excavator. By utilizing the fast response characteristic of the electric motor, the motor speed is directly controlled according to the movement amplitude of the pilot handle, that is, the pilot pressure, so as to achieve the purpose of controlling the movement of the entire vehicle. At the same time, the actual operating conditions can be judged according to the load pressure and the pilot pressure, and the constant power external characteristic curves of the motor under different operating conditions can be distinguished, so as to achieve the purpose of increasing efficiency and saving energy.

[0133] Figure 6 An example of a physical structure diagram of an electronic device is shown below. Figure 6As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630, and a communication bus 640, wherein the processor 610, the communication interface 620, and the memory 630 communicate with each other via the communication bus 640. The processor 610 may call logic instructions in the memory 630 to execute a motor speed control method, which is applied to a working machine and includes: obtaining a pilot pressure and a load pressure of the working machine and determining the maximum power of the motor of the working machine; determining the theoretical motor speed corresponding to the pilot pressure under the current working action based on a first mapping relationship; wherein the first mapping relationship is used to represent the correspondence between the pilot pressure and the theoretical motor speed under each working action; determining the maximum motor speed corresponding to the load pressure based on a second mapping relationship and the maximum motor power; wherein the second mapping relationship is used to represent the correspondence between the load pressure and the maximum motor speed under each maximum motor power; comparing the theoretical motor speed with the maximum motor speed, and determining the motor speed of the working machine based on the comparison result.

[0134] In addition, the logic instructions in the above-mentioned memory 630 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0135] On the other hand, the present invention also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the motor speed control method provided by the above-mentioned methods. The method is applied to an operating machine, including: obtaining the pilot pressure and load pressure of the operating machine, and determining the maximum power of the motor of the operating machine; based on a first mapping relationship, determining the theoretical speed of the motor corresponding to the pilot pressure under the current operating action; wherein the first mapping relationship is used to characterize the correspondence between the pilot pressure and the theoretical speed of the motor under each operating action; based on the second mapping relationship and the maximum power of the motor, determining the maximum speed of the motor corresponding to the load pressure; wherein the second mapping relationship is used to characterize the correspondence between the load pressure and the maximum speed of the motor under the maximum power of each motor; comparing the theoretical speed of the motor with the maximum speed of the motor, and determining the motor speed of the operating machine based on the comparison result.

[0136] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the above-mentioned motor speed control method provided. The method is applied to an operating machine, and includes: obtaining the pilot pressure and load pressure of the operating machine, and determining the maximum power of the motor of the operating machine; based on a first mapping relationship, determining the theoretical speed of the motor corresponding to the pilot pressure under the current operating action; wherein the first mapping relationship is used to characterize the correspondence between the pilot pressure and the theoretical speed of the motor under each operating action; based on the second mapping relationship and the maximum power of the motor, determining the maximum speed of the motor corresponding to the load pressure; wherein the second mapping relationship is used to characterize the correspondence between the load pressure and the maximum speed of the motor under the maximum power of each motor; comparing the theoretical speed of the motor with the maximum speed of the motor, and determining the motor speed of the operating machine based on the comparison result.

[0137] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0138] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for controlling the speed of a motor, characterized in that: Applicable to operating machinery, including: Obtaining a pilot pressure and a load pressure of the operating machine, and obtaining a rate of change of the load pressure of the operating machine; if the load pressure rate of change does not exceed a preset rate of change threshold, using a first power value as the maximum power of the motor of the operating machine; if the load pressure rate of change exceeds the preset rate of change threshold and lasts for a period exceeding a preset duration threshold, using a second power value as the maximum power of the motor of the operating machine; Determining the theoretical motor speed corresponding to the pilot pressure under the current operation based on a first mapping relationship; wherein the first mapping relationship is used to represent the corresponding relationship between the pilot pressure and the theoretical motor speed under each operation; Determining the maximum speed of the motor corresponding to the load pressure based on a second mapping relationship and the maximum power of the motor; wherein the second mapping relationship is used to represent the corresponding relationship between the load pressure and the maximum speed of the motor at the maximum power of each motor; The theoretical motor speed is compared with the maximum motor speed, and the motor speed of the working machine is determined based on a result of the comparison.

2. The motor speed control method according to claim 1, characterized in that: If the load pressure change rate exceeds the preset change rate threshold and the duration exceeds the preset duration threshold, the second power value is used as the maximum power of the motor of the working machine, including: If the load pressure change rate exceeds the preset change rate threshold and the duration exceeds the preset duration threshold, determining the operating condition of the operating machine according to the pilot pressure; determining whether the operating machine is performing a specific operating action based on the operating condition; If it is determined that the working machine is performing a specific working action, the motor power value corresponding to the specific working action is used as the second power value; The second power value is used as the maximum power of the motor of the working machine.

3. The motor speed control method according to claim 1, characterized in that: When the current operation action is a compound action, determining the motor theoretical speed corresponding to the pilot pressure under the current operation action based on the first mapping relationship includes: Based on the first mapping relationship, respectively determining the theoretical rotational speed corresponding to the pilot pressure in each working action in the compound action; The theoretical partial speeds are summed, and the summation result is used as the theoretical speed of the motor.

4. The method for controlling the motor speed according to claim 1, wherein: The step of comparing the theoretical motor speed with the maximum motor speed and determining the motor speed of the working machine based on the comparison result includes: If the theoretical speed of the motor is less than the maximum speed of the motor, the theoretical speed of the motor is used as the motor speed of the working machine; If the theoretical speed of the motor is greater than or equal to the maximum speed of the motor, the maximum speed of the motor is used as the motor speed of the working machine.

5. A motor speed control device, characterized in that: include: an acquisition module, configured to acquire the pilot pressure and the load pressure of the operating machine, and acquire the load pressure change rate of the operating machine; If the load pressure change rate does not exceed the preset change rate threshold, the first power value is used as the maximum power of the motor of the working machine; if the load pressure change rate exceeds the preset change rate threshold and the duration exceeds the preset duration threshold, the second power value is used as the maximum power of the motor of the working machine; A first processing module is configured to determine, based on a first mapping relationship, a theoretical motor speed corresponding to the pilot pressure in a current operation; wherein the first mapping relationship is configured to represent a correspondence between the pilot pressure and the theoretical motor speed in each operation; a second processing module, configured to determine the maximum motor speed corresponding to the load pressure based on a second mapping relationship and the maximum motor power; wherein the second mapping relationship is used to represent the corresponding relationship between the load pressure and the maximum motor speed at the maximum power of each motor; The third processing module is configured to compare the theoretical speed of the motor with the maximum speed of the motor, and determine the speed of the motor of the working machine based on a result of the comparison.

6. A method for controlling a hydraulic system, characterized in that: include: Determining the motor speed of the working machine by the motor speed control method according to any one of claims 1 to 4; The output flow of the hydraulic pump in the hydraulic system is controlled according to the motor speed.

7. A hydraulic system, characterized in that: The hydraulic system uses the control method of the hydraulic system according to claim 6.

8. A working machine, characterized in that: Comprising the hydraulic system of claim 7.

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