Motor and pump power bidirectional real-time matching control method and device and excavator

Abstract

The invention relates to a motor and pump power two-way real-time matching control method and device and an excavator, and the method comprises the steps that whether a hydraulic pump exceeds preset power or not is judged according to the pressure change rate and interval effective pressure of the hydraulic pump; if yes, the synchronous rotating speed of the driving motor is calculated, and then the slip frequency value of the driving motor is calculated, and if not, the process returns to recalculate the power of the hydraulic pump; according to the slip value, the target rotating speed of the driving motor and the target pump power of the hydraulic pump are calculated; according to the target rotating speed and the pump pressure change rate, the actual adjusting rotating speed of the driving motor is calculated; and adjusting the displacement of the hydraulic pump according to the target pump power, and adjusting the power of the driving motor according to the actual adjustment rotating speed. By dynamically adjusting the rotating speed of the motor, when the pump power is too large, the pump power can be reduced in real time, meanwhile, the torque of the motor can be increased by changing the transient rotating speed of the motor, the situation of instantaneous motor stalling is avoided, and bidirectional real-time matching of the motor and the pump power is optimized.

Description

Technical Field

[0001] The present application relates to the technical field of engineering machinery control, and more specifically to a method and device for bidirectional real-time matching control of a motor and a pump power of an excavator, and an excavator. Background Art

[0002] Excavators traditionally rely mainly on fuel engines for power, and the flow control algorithm in their hydraulic system is usually based on the adjustment of the hydraulic pump flow to match the transmission relationship between the engine and the pump to achieve stable and efficient excavation operations; however, with the advancement of technology and the increasing demand for energy conservation and emission reduction, motor-driven excavators are gradually replacing traditional fuel excavators and becoming an important direction for the development of the industry; therefore, the research on motor-driven pump flow control algorithms is of great significance to the improvement of the overall performance of excavators, including improving work efficiency, reducing energy consumption, and reducing environmental pollution.

[0003] The hydraulic pump system driven by a fuel engine has a relatively mature design and operating mechanism, and its flow control algorithm is relatively simple. However, it is limited by the dynamic characteristics of the engine's own speed and may require a more complex mechanical or hydraulic system to adjust, with low control accuracy and response speed. In contrast, motor-driven excavators have demonstrated obvious technical advantages in pump flow control. By combining modern electronic control technology, the motor-driven system can achieve precise and rapid pump flow regulation and can dynamically adapt to complex working conditions. Compared with fuel engines, the motor has a fast dynamic response speed, which can significantly improve the operating efficiency of the excavator under changing working conditions.

[0004] However, when the motor-driven hydraulic pump encounters an overload condition, the motor and transmission mechanism may be seriously damaged due to stalling. At the same time, in the case of stalling, the pump flow rate suddenly decreases, causing instability in the excavator's operation, affecting operational safety and operator experience. Summary of the invention

[0005] The present application provides a method, device and excavator for controlling bidirectional real-time matching of motor and pump power. The method can dynamically adjust the motor speed. When the pump power is too large, the pump power can not only be reduced in real time, but also the motor torque can be increased by changing the transient speed of the motor, thereby avoiding instantaneous motor stalling and optimizing the bidirectional real-time matching of motor and pump power.

[0006] In a first aspect, the present application provides a bidirectional real-time matching control method for the motor and pump power of an excavator, the method comprising: judging whether the hydraulic pump exceeds a preset power according to the pressure change rate and the interval effective pressure of the hydraulic pump; if so, calculating the synchronous speed of the drive motor, and then calculating the slip value of the drive motor, if not, returning to recalculate the hydraulic pump power; calculating the target speed of the drive motor and the target pump power of the hydraulic pump according to the slip value; calculating the actual adjusted speed of the drive motor according to the target speed and the pump pressure change rate; adjusting the displacement of the hydraulic pump according to the target pump power, and adjusting the power of the drive motor according to the actual adjusted speed.

[0007] In an optional solution of the first aspect, when determining whether the hydraulic pump is in an overload state, the method includes: assuming that the pressure change rate of the hydraulic pump is dP / dt, and expressed as ΔP; calculating the interval effective pressure according to the real-time effective hydraulic pump pressure and the real-time weight coefficient:

[0008] P l =∑(P m ·K m ) / n, where P m is the real-time effective hydraulic pump pressure, K m is the real-time weight coefficient of effective pilot pressure matching, P l is the effective pressure of the interval; according to the effective pressure of the interval, the power of the hydraulic pump is calculated: W l =P l Q l , where Q l is the hydraulic pump flow rate within the effective range; and the hydraulic pump power is compared with the preset power.

[0009] In an optional scheme of the first aspect, after calculating the interval effective pressure, the method includes: judging whether the interval effective pressure is less than a preset pressure value, and whether the pressure change rate is greater than the preset change rate; if so, judging the excavator as being in the startup stage of voltage fluctuation or action, and not executing the subsequent adjustment steps of the hydraulic pump and the drive motor; if not, judging whether the interval effective pressure is greater than the preset pressure value, and whether the pressure change rate is greater than the preset change rate; if so, judging the excavator as being in a load operating condition, and executing the subsequent adjustment steps of the hydraulic pump and the drive motor; if not, returning to recalculate the hydraulic pump power.

[0010] In an optional scheme of the first aspect, when calculating the slip value of the drive motor, the method includes: calculating the synchronous speed of the drive motor: Ns=120·f / p, where f is the power supply frequency and p is the number of pole pairs of the drive motor; calculating the slip value of the drive motor according to the synchronous speed and actual speed of the drive motor: S=(Ns-Nr) / Ns, where Nr is the rotor speed of the drive motor.

[0011] In an optional solution of the first aspect, when calculating the target speed of the drive motor, the method includes: calculating the target speed of the drive motor according to the slip value:

[0012] Na=Nd·(1-S)=Nd·(1-(Ns-Nr) / Ns), wherein Nd is the set speed of the drive motor.

[0013] In an optional solution of the first aspect, when calculating the target pump power of the hydraulic pump, the method includes: setting a weight coefficient L and a weight coefficient M; wherein L and M are normalized values ​​of the hydraulic pump interval effective pressure and the hydraulic pump pressure change rate, respectively, wherein L=∑(P m ·K m ) / n·P max , P max is the overflow pressure, i.e. the maximum pressure; where M = ΔP / ΔP max , ΔP max is the maximum change rate value, that is, the estimated value; according to the weight coefficient L, the weight coefficient M and the slip value, the target pump power of the hydraulic pump is calculated:

[0014] W=P·q·n·(∑(P m ·K m ) / n·P max )·(ΔP / ΔP max )·((Ns-Nr) / Ns).

[0015] In an optional solution of the first aspect, when calculating the actual adjusted speed of the drive motor, the method includes: controlling a normalization coefficient according to a target speed and a pump pressure change rate to calculate the actual adjusted speed of the drive motor: Na=Nd·(1-(Ns-Nr) / Ns)·(ΔP / ΔP max ).

[0016] In an optional solution of the first aspect, the power of the drive motor is adjusted according to a preset safety margin and an actually adjusted rotation speed.

[0017] In the second aspect, the present application provides a bidirectional real-time matching control device of motor and pump power using the above-mentioned control method, including: a power comparison module, used to calculate the hydraulic pump power according to the pressure change rate and interval effective pressure of the hydraulic pump and compare the hydraulic pump power with the preset power; a slip calculation module, used to calculate the synchronous speed of the drive motor, and then calculate the slip value of the drive motor; a motor calculation module, used to calculate the target speed of the drive motor according to the slip value, and then calculate the actual adjusted speed of the drive motor according to the target speed and the pump pressure change rate; a pump calculation module, used to calculate the target pump power of the hydraulic pump according to the slip value; an adjustment control module, used to adjust the displacement of the hydraulic pump according to the target pump power, and adjust the power of the drive motor according to the actual adjusted speed.

[0018] On the second aspect, the present application provides an excavator including the above-mentioned control device, and also includes: a pump pressure sensor for obtaining pressure data of the hydraulic pump; a pump solenoid valve for adjusting the flow rate of the liquid in the hydraulic pump; a drive motor for assisting in adjusting the flow rate of the liquid in the hydraulic pump; a frequency converter for controlling the speed of the drive motor; a control unit for adjusting the displacement of the hydraulic pump and adjusting the transient speed of the drive motor to optimize the two-way real-time matching of the drive motor and the hydraulic pump power.

[0019] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate one or more embodiments of the present application and, together with the description, serve to explain the principles of the present application and to enable one of ordinary skill in the relevant art to make and use the present application.

[0021] Figure 1 is a connection diagram of an exemplary hydraulic pump according to some embodiments of the present application.

[0022] Figure 2 It is a schematic diagram of an exemplary inverse relationship curve between pump pressure and flow rate according to some embodiments of the present application.

[0023] Figure 3 It is a flowchart of an exemplary method for bidirectional real-time matching control of motor and pump power according to some embodiments of the present application.

[0024] Figure 4 It is a flowchart of an exemplary working condition judgment method according to some embodiments of the present application.

[0025] Figure 5This is a schematic diagram of module connections of an exemplary motor and pump power bidirectional real-time matching control device according to some embodiments of the present application.

[0026] Figure 6 It is a schematic diagram of the structure of an exemplary electronic device according to some embodiments of the present application. DETAILED DESCRIPTION

[0027] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the present application will be more comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application.

[0028] First, a brief introduction is given to the excavator used in this application.

[0029] Specifically, the hydraulic structure of the excavator used in the present application includes at least a hydraulic pump 10, a hydraulic cylinder 11, a pump solenoid valve 12, an oil pool, a cooler, a drive motor 14 and a frequency converter 15, as shown in FIG. Figure 1 As shown, Figure 1 A connection diagram of an exemplary hydraulic pump of some embodiments of the present application is shown; wherein:

[0030] The hydraulic pump 10 is the power source of the hydraulic system of the excavator. It is mainly used to compress the oil required by the machine into high-pressure oil, and then transport it to the hydraulic cylinder 11 through a pipeline. In the hydraulic pump 10, the liquid enters from the low-pressure side, and then is compressed into high-pressure oil and output to the high-pressure side through the action of components such as gears or plungers. The output flow and pressure of the hydraulic pump 10 have a crucial impact on the working efficiency and load capacity of the entire system. Among them, the hydraulic pump 10 is also connected to a pump pressure sensor 13, and the pressure data of the hydraulic pump 10 is obtained through the pump pressure sensor 13.

[0031] The hydraulic cylinder 11 is mainly used to convert oil into mechanical energy, thereby driving the movement of the machine. In the hydraulic cylinder 11, the oil enters the cylinder body through the pressure pipe, exerts pressure on the hydraulic piston inside the cylinder body, thereby driving the movement of the mechanism. The internal structure and size of the hydraulic cylinder 11 are usually related to the movement trajectory and load of the machine.

[0032] The pump solenoid valve 12 is mainly used to adjust the flow rate of the oil in the hydraulic pump 10;

[0033] The oil pool is mainly used to store oil, cool and filter oil. The oil pool is usually designed to be open or closed to facilitate the addition and replacement of oil.

[0034] The cooler adopts water cooling or air cooling, which can effectively reduce the temperature of the oil, thereby improving the working efficiency and reliability of the system.

[0035] The driving motor 14 mainly provides a power source for the hydraulic pump 10, so that the hydraulic pump 10 can complete the compression and delivery of the oil. According to the driving mode of the excavator, the driving motor 14 usually uses a three-phase asynchronous motor or a permanent magnet synchronous motor.

[0036] The frequency converter 15 is usually used to adjust the speed and output torque of the drive motor 14, so as to achieve precise control of the flow and pressure of the hydraulic pump 10; the frequency converter 15 adjusts the operating state of the drive motor 14 by changing the frequency and voltage of the input power supply, for example, by reducing the motor speed by lowering the frequency, thereby reducing the output flow of the hydraulic pump 10; by increasing the frequency to increase the speed of the drive motor 14, high flow requirements can be met.

[0037] In some embodiments, the excavator of the present application can be set as a normal manually operated excavator, or as an unmanned excavator with a cab, or as an unmanned excavator without a cab. In this embodiment, the reference excavator adopts an unmanned excavator with a cab, so that the operator can monitor the operation of the excavator in the cab and manually operate the excavator under abnormal circumstances.

[0038] In some embodiments of the present application, the basic flow control method of the excavator is a constant power control method of the main pump, and the motor control is that the inverter 15 controls the three-phase AC asynchronous motor and adjusts it by setting different speeds.

[0039] Therefore, the power calculation process of the hydraulic pump 10 of the present application is as follows:

[0040] The power W of hydraulic pump 10 is P×Q, where P is the pressure of the main pump and Q is the flow rate of the main pump; wherein the flow rate Q is q×n, where q is the displacement of the main pump and n is the rotation speed of the main pump.

[0041] Therefore, the power of the hydraulic pump 10 may also be W=P×q×n.

[0042] Specifically, in order to ensure constant power control, P and Q, that is, the pressure and flow rate of the hydraulic pump 10 are inversely proportional. Figure 2 As shown, Figure 2 A schematic diagram of an exemplary inverse relationship curve between pump pressure and flow rate according to some embodiments of the present application is shown.

[0043] Exemplarily, the initial power of the hydraulic pump 10 is set to Wi , the initial pressure of the hydraulic pump 10 is set to P i According to the above calculation formula of the flow rate of the hydraulic pump 10 and the power of the hydraulic pump 10, it can be known that Q = W i / P i .

[0044] Therefore, the power calculation process of the drive motor 14 of the present application is as follows:

[0045] The real-time power of the drive motor 14 can be calculated by measuring the current, voltage and power factor. For a three-phase AC motor, the calculation formula for real-time power is the same, but real-time data is required. That is, the calculation formula for real-time power is:

[0046] P 实时 =√3×U×I×cosφ, where U is voltage, I is current, and cosφ is the power factor of the drive motor 14.

[0047] In actual real-time processes, since the motor load and power factor may change over time, real-time power calculation and monitoring are usually achieved through sensors or online monitoring devices, which continuously monitor parameters such as current, voltage, power factor, etc., and calculate the motor power in real time.

[0048] In some embodiments of the present application, a suitable power of the drive motor 14 is selected according to the power requirement of the hydraulic pump 10. The power of the drive motor 14 should be greater than or equal to the power requirement of the hydraulic pump 10 to ensure that the drive motor 14 can drive the hydraulic pump 10 to work normally. In addition, the power of the drive motor 14 should take into account a certain safety margin, usually 10% to 20%.

[0049] Therefore, reference Figure 3 As shown, Figure 3 The flowchart of an exemplary motor and pump power bidirectional real-time matching control method according to some embodiments of the present application. One aspect of the present invention provides a motor and pump power bidirectional real-time matching control method for an excavator, the method comprising:

[0050] S1: judging whether the hydraulic pump 10 exceeds a preset power according to the pressure change rate and the interval effective pressure of the hydraulic pump 10.

[0051] Specifically, in step S1, when determining whether the hydraulic pump 10 is in an overload state, the method includes:

[0052] Assume that the pressure of the hydraulic pump 10 is P, and the pressure change rate of the hydraulic pump 10 is dP / dt, which is expressed as ΔP. ​​When the pressure change rate is large, it is necessary to judge the effective value of the interval at this time (where the real-time pressure value as a basis for judgment will cause some interference). During the effective working time, the real-time effective pump pressure corresponding to the effective pilot pressure is P m , the corresponding real-time weight coefficient is K m , and the actual interval effective pressure is P l .

[0053] Then, the interval effective pressure is calculated according to the real-time effective hydraulic pump 10 pressure and the real-time weight coefficient:

[0054] P l =∑(P m ·K m ) / n; Calculate the power of hydraulic pump 10 according to the effective pressure of the interval: W l =P l Q l , where Q l is the flow rate of the hydraulic pump 10 within the effective range; according to the above formula, it can be known that under the condition of constant hydraulic pump 10 power, the pressure is inversely proportional to the flow rate, that is, the commonly used PQ curve, where Q = q × n, Q is the flow rate of the hydraulic pump 10, q is the displacement of the hydraulic pump 10, and n is the pump speed.

[0055] In the control of the hydraulic pump 10, the actual controlled component is the pump electromagnetic proportional valve, that is, the control of the displacement of the hydraulic pump 10, that is, by controlling the displacement of the hydraulic pump 10, the actual output power of the hydraulic pump 10 can be controlled. However, according to the above-mentioned PQ curve, when the displacement of the hydraulic pump 10 is large, it will cause excessive instantaneous flow, which will also cause excessive pressure, causing overflow, resulting in energy waste and motor stalling. Therefore, in this application, the judgment of excessive load is made based on the above-mentioned real-time pressure change rate and interval effective pressure of the hydraulic pump 10.

[0056] In some examples of this application, reference Figure 4 As shown, Figure 4 is a flow chart of an exemplary working condition judgment method according to some embodiments of the present application. After calculating the effective pressure of the interval, the method includes:

[0057] S11: Determine whether the effective pressure of the interval is less than a preset pressure value, and whether the pressure change rate is greater than a preset change rate.

[0058] If yes, then S12 is executed: the excavator is determined to be in the voltage fluctuation or action start-up phase, and the subsequent adjustment steps of the hydraulic pump 10 and the drive motor 14 are not executed.

[0059] If not, then execute S13: determine whether the interval effective pressure is greater than a preset pressure value, and whether the pressure change rate is greater than a preset change rate.

[0060] If yes, then execute S14: determine the excavator as being in a load operation condition, and execute subsequent adjustment steps of the hydraulic pump 10 and the drive motor 14; if no, then return to recalculate the power of the hydraulic pump 10.

[0061] Specifically, in order to distinguish the demand for the power output of the hydraulic pump 10 due to the actual operating conditions of the hydraulic pump 10, when the interval effective pressure of the hydraulic pump 10 is small and the pressure change rate of the hydraulic pump 10 is large, it means that the excavator may be in some voltage fluctuations or the start-up stage of the action, and at this time, a larger hydraulic pump 10 power is not really needed to adapt to the control requirements; when the interval effective pressure of the hydraulic pump 10 is large and the pressure change rate of the hydraulic pump 10 is large, it means that the excavator is in a real high-load condition, for example, the excavator arm suddenly switches from a no-load state to an actual excavation state, and at this time, a larger hydraulic pump 10 power is needed to adapt to the control requirements.

[0062] S2: If yes, then calculate the synchronous speed of the drive motor 14 and then calculate the slip value of the drive motor 14; if no, return to recalculate the power of the hydraulic pump 10.

[0063] Specifically, the power source of the electric excavator is a drive motor 14 that adopts a three-phase AC asynchronous motor. For the drive motor 14 controlled by the inverter 15, if it is detected that the load is too large, the usual practice is to reduce the speed of the drive motor 14. When the load is too large, the drive motor 14 may exceed its rated current and cause overload; reducing the speed can reduce the output torque of the drive motor 14, thereby reducing the current and preventing the drive motor 14 from overloading and damage. In addition, reducing the speed can help the drive motor 14 run more stably and avoid frequent shutdowns or failures due to excessive load.

[0064] When the load is too large, the drive motor 14 will try to increase the torque to meet the load requirements. At this time, the speed of the drive motor 14 may decrease, but this does not mean that the drive motor 14 can continue to provide sufficient torque. When the load is too large, the slip of the drive motor 14 will increase, causing the speed of the drive motor 14 to decrease. Although theoretically, the speed reduction can lead to an increase in torque, in actual applications, the drive motor 14 may not be able to provide sufficient torque due to overload, and may even enter a protection state.

[0065] For the drive motor 14, power (P) is the product of torque (T) and rotational speed (N), that is, P=T×N. Under a certain power, when the rotational speed decreases, the torque can increase, and vice versa.

[0066] Therefore, according to the above content, when calculating the slip value of the drive motor 14, the synchronous speed Ns=120·f / p of the drive motor 14 must be calculated first, where f is the power frequency and p is the number of pole pairs of the drive motor 14. The slip value S is the difference between the synchronous speed and the actual speed, and the actual calculation formula is: S=(Ns-Nr) / Ns, where Nr is the rotor speed of the drive motor 14.

[0067] S3: Calculate the target rotation speed of the drive motor 14 and the target pump power of the hydraulic pump 10 according to the slip value.

[0068] Specifically, although the increase in the load of the drive motor 14 has the highest real-time monitoring performance for current, due to some electromagnetic interference, current monitoring is inaccurate. Therefore, the present application uses the slip value to monitor and determine the real-time load of the hydraulic pump 10. That is, when the slip value is larger, it can be determined that the load of the drive motor 14 is heavier at this time. At this time, the speed should be reduced to increase the torque and protect the motor itself. Therefore, the calculation formula for calculating the target speed of the drive motor 14 is:

[0069] Na=Nd·(1-S)=Nd·(1-(Ns-Nr) / Ns), wherein Nd is the set rotation speed of the drive motor 14.

[0070] Specifically, the relationship between pump power and displacement is calculated as W=P×q×n, and a weight coefficient L is set, which is inversely proportional to the effective pressure of the hydraulic pump 10 intervals, and a weight coefficient M is set, which is proportional to the pressure change rate of the pump, so W=P×q×n×L×M; wherein L and M are normalized values ​​of the effective pressure of the hydraulic pump 10 intervals and the pressure change rate of the hydraulic pump 10, respectively, wherein L=∑(P m ·K m ) / n·P max , P max is the overflow pressure, i.e. the maximum pressure; where M = ΔP / ΔP max , ΔP max is the maximum change rate value, that is, the estimated value; therefore, the final calculation formula for the corresponding displacement of the pump power is: W = P·q·n·(∑(P m ·K m ) / n·P max )·(ΔP / ΔP max ).

[0071] There is a very close relationship between the control of the hydraulic pump 10 and the control of the drive motor 14. When the flow rate and the rate of change of the hydraulic pump 10 are detected to increase, it can be predicted that the load of the drive motor 14 will also increase synchronously. Therefore, the synchronous reduction of the speed of the drive motor 14 will play a certain protective role on the drive motor 14. Therefore, according to the above calculation formula of the final pump power corresponding to the displacement, the displacement in the control of the hydraulic pump 10 is added with the slip coefficient control, so the pump displacement is:

[0072] W=P·q·n·(∑(P m ·K m ) / n·P max )·(ΔP / ΔP max )·((Ns-Nr) / Ns).

[0073] S4: Calculate the actual adjusted speed of the drive motor 14 according to the target speed and the pump pressure change rate.

[0074] Specifically, when calculating the actual adjustment speed of the drive motor 14, the pressure change rate control normalization coefficient in the control of the hydraulic pump 10 is added to the speed control of the drive motor 14 (wherein, the interval effective pressure normalization coefficient cannot be added because the coefficient represents the actual load size of the pump and cannot be introduced to reduce the motor speed). Therefore, the calculation formula for the adjustment speed of the drive motor 14 is: Na = Nd·(1-(Ns-Nr) / Ns)·(ΔP / ΔP max ).

[0075] S5: adjusting the displacement of the hydraulic pump 10 according to the target pump power, and adjusting the speed and the power of the driving motor 14 according to the actual adjustment.

[0076] Therefore, the present application adopts the above technical solution, through real-time calculation based on the pressure change rate of the hydraulic pump 10 and the effective pressure of the interval, combined with the slip value of the drive motor 14, dynamically adjusts the displacement of the hydraulic pump 10 and the motor speed, realizes the two-way real-time matching control of the power of the hydraulic pump 10 and the drive motor 14, and effectively improves the coordination and stability of the system operation. Specifically, in the case of a sudden increase in load, the displacement of the hydraulic pump 10 is timely reduced by monitoring the pressure change rate and the effective pressure of the interval, reducing the high-pressure impact of the hydraulic pump 10 and preventing overload damage; the slip value is used to monitor the load state of the drive motor 14, and the impact of overload on the drive motor 14 is reduced by reducing the speed of the drive motor 14, avoiding overheating, frequent shutdown or failure of the drive motor 14, thereby extending the service life of the equipment, and using the slip value instead of current monitoring for load judgment to avoid the problem of inaccurate current monitoring caused by electromagnetic interference, and improve the anti-interference ability of the system.

[0077] Furthermore, through the combined judgment of the interval effective pressure and the pressure change rate, different operating conditions of the excavator, such as start-up, light load and heavy load, can be distinguished, ensuring that the hydraulic pump 10 and the drive motor 14 can quickly respond to changes in operating conditions; during the conversion of the excavator boom from no load to heavy load, the power of the hydraulic pump 10 and the speed of the drive motor 14 can be adjusted in real time to avoid unstable operations caused by changes in operating conditions.

[0078] In some embodiments, reference Figure 5 As shown, Figure 5 The present invention relates to a motor and pump power bidirectional real-time matching control device using the above control method, comprising:

[0079] The power comparison module 101 is used to calculate the power of the hydraulic pump 10 according to the pressure change rate and the interval effective pressure of the hydraulic pump 10 and compare the power of the hydraulic pump 10 with the preset power;

[0080] The slip calculation module 102 is used to calculate the synchronous speed of the drive motor 14 and then calculate the slip value of the drive motor 14;

[0081] The motor calculation module 103 is used to calculate the target speed of the drive motor 14 according to the slip value, and then calculate the actual adjustment speed of the drive motor 14 according to the target speed and the pump pressure change rate;

[0082] A pump calculation module 104, for calculating a target pump power of the hydraulic pump 10 according to the slip value;

[0083] The adjustment control module 105 is used to adjust the displacement of the hydraulic pump 10 according to the target pump power, and adjust the power of the drive motor 14 according to the actual adjustment speed.

[0084] In some embodiments, reference Figure 6 As shown, Figure 6 The structural diagram of an exemplary electronic device of some embodiments of the present application is shown. The electronic device includes: a memory 201 and a processor 202, and the memory 201 stores a computer program that can be run on the processor 202. When the processor 202 executes the computer program, the method in the above embodiment is implemented. The number of the memory 201 and the processor 202 can be one or more.

[0085] The electronic device also includes:

[0086] The communication interface 203 is used to communicate with external devices and perform data exchange transmission.

[0087] If the memory 201, the processor 202 and the communication interface 203 are implemented independently, the memory 201, the processor 202 and the communication interface 203 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0088] Optionally, in a specific implementation, if the memory 201, the processor 202 and the communication interface 203 are integrated on a chip, the memory 201, the processor 202 and the communication interface 203 can communicate with each other through an internal interface.

[0089] An embodiment of the present application provides a computer-readable storage medium storing a computer program, which implements the method provided in the embodiment of the present application when the program is executed by the processor 202.

[0090] The embodiment of the present application also provides a chip, which includes a processor 202, which is used to call and execute instructions stored in the memory 201 from the memory 201, so that a communication device equipped with the chip executes the method provided by the embodiment of the present application.

[0091] The embodiment of the present application also provides a chip, including: an input interface, an output interface, a processor 202 and a memory 201. The input interface, the output interface, the processor 202 and the memory 201 are connected through an internal connection path. The processor 202 is used to execute the code in the memory 201. When the code is executed, the processor 202 is used to execute the method provided in the embodiment of the application.

[0092] It should be understood that the processor 202 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. It is worth noting that the processor may be a processor 202 that supports the Advanced RISC Machines (ARM) architecture.

[0093] Further, the above-mentioned memory 201 may include a read-only memory and a random access memory, and may also include a non-volatile random access memory. The memory 201 may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may include a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may include a random access memory (RAM), which is used as an external cache. By way of exemplary but not limiting description, many forms of RAM are available. For example, static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM) and direct memory bus random access memory (DR RAM).

[0094] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function according to the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium.

[0095] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for real-time bidirectional matching control of motor and pump power of an excavator, characterized in that: The method comprises: Determining whether the hydraulic pump exceeds a preset power according to the pressure change rate and the interval effective pressure of the hydraulic pump; If yes, then the synchronous speed of the drive motor is calculated, and then the slip value of the drive motor is calculated; if no, then the hydraulic pump power is recalculated; Calculating a target speed of the drive motor and a target pump power of the hydraulic pump according to the slip value; Calculating the actual adjusted speed of the drive motor according to the target speed and the pump pressure change rate; The displacement of the hydraulic pump is adjusted according to the target pump power, and the power of the drive motor is adjusted according to the actual adjustment speed.

2. The control method according to claim 1, characterized in that: When determining whether the hydraulic pump is in an overload state, the method includes: Assume that the pressure change rate of the hydraulic pump is dP / dt, and is represented by ΔP; According to the real-time effective hydraulic pump pressure and the real-time weight coefficient, the interval effective pressure is calculated: P l =∑(P m ·K m ) / n, Among them, P m is the real-time effective hydraulic pump pressure, K m is the real-time weight coefficient of effective pilot pressure matching, P l is the effective pressure of the interval; According to the effective pressure of the interval, calculate the power of the hydraulic pump: W l =P l Q l , where Q l is the hydraulic pump flow rate within the effective range; The hydraulic pump power is compared with a preset power.

3. The control method according to claim 2, characterized in that: After calculating the effective pressure of the interval, the method includes: Determine whether the effective pressure in the interval is less than a preset pressure value, and whether the pressure change rate is greater than a preset change rate; If yes, the excavator is judged to be in the voltage fluctuation or action start-up stage, and the subsequent adjustment steps of the hydraulic pump and the drive motor are not performed. If no, it is judged whether the effective pressure in the interval is greater than the preset pressure value, and whether the pressure change rate is greater than the preset change rate; If yes, the excavator is judged to be in a load operation condition, and subsequent adjustment steps of the hydraulic pump and the drive motor are performed. If no, the process returns to recalculate the hydraulic pump power.

4. The control method according to claim 1, characterized in that: When calculating the slip value of the drive motor, the method includes: Calculate the synchronous speed of the drive motor: Ns = 120 f / p, where f is the power frequency and p is the number of pole pairs of the drive motor; According to the synchronous speed and actual speed of the driving motor, the slip value of the driving motor is calculated: S = (Ns-Nr) / Ns, where Nr is the rotor speed of the driving motor.

5. The control method according to claim 1 or 4, characterized in that: When calculating the target speed of the driving motor, the method includes: According to the slip value, the target speed of the drive motor is calculated: Na=Nd·(1-S)=Nd·(1-(Ns-Nr) / Ns), wherein Nd is the set speed of the drive motor.

6. The control method according to claim 5, characterized in that: When calculating the target pump power of the hydraulic pump, the method includes: Set the weight coefficient L and weight coefficient M; where L and M are the normalized values ​​of the hydraulic pump interval effective pressure and the hydraulic pump pressure change rate, respectively, where L = ∑(P m ·K m ) / n·P max , P max is the overflow pressure, i.e. the maximum pressure; where M = ΔP / ΔP max , ΔP max is the maximum rate of change value, i.e. the estimated value; According to the weight coefficient L, the weight coefficient M and the slip value, the target pump power of the hydraulic pump is calculated: W=P·q·n·(∑(P m ·K m ) / n·P max )·(ΔP / ΔP max )·((Ns-Nr) / Ns)。 7. The control method according to claim 5, characterized in that: When calculating the actual adjusted speed of the drive motor, the method includes: According to the target speed and the pump pressure change rate control normalization coefficient, the actual adjustment speed of the drive motor is calculated: Na=Nd·(1-(Ns-Nr) / Ns)·(ΔP / ΔP max )。 8. The control method according to claim 1, characterized in that: in, The power of the drive motor is adjusted according to a preset safety margin and an actual adjustment speed.

9. A motor and pump power bidirectional real-time matching control device using the control method according to any one of claims 1 to 8, characterized in that: include: A power comparison module, used to calculate the power of the hydraulic pump according to the pressure change rate and the interval effective pressure of the hydraulic pump and compare the power of the hydraulic pump with a preset power; A slip calculation module is used to calculate the synchronous speed of the drive motor and then calculate the slip value of the drive motor; a motor calculation module, used to calculate a target speed of the drive motor according to the slip value, and further calculate an actual adjusted speed of the drive motor according to the target speed and a pump pressure change rate; A pump calculation module, used for calculating a target pump power of the hydraulic pump according to the slip value; The adjustment control module is used to adjust the displacement of the hydraulic pump according to the target pump power, and to adjust the power of the drive motor according to the actual adjustment speed.

10. An excavator, characterized in that: The device for controlling the bidirectional real-time matching of motor and pump power according to claim 9 further comprises: Pump pressure sensor, used to obtain pressure data of hydraulic pump; Pump solenoid valve, used to adjust the flow of liquid in the hydraulic pump; A driving motor, used to assist in regulating the flow rate of the liquid in the hydraulic pump; Frequency converter, used to control the speed of the drive motor; The control unit is used to adjust the displacement of the hydraulic pump and adjust the transient speed of the drive motor to optimize the two-way real-time matching of the drive motor and the hydraulic pump power.

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