Automatic calibration device and method for electronic control main pump and efficiency compensation method of electronic control main pump

Abstract

The invention discloses an automatic calibration device and method for an electric control main pump and an efficiency compensation method thereof in the technical field of excavator control, and aims to solve the problem that in the prior art, the consistency difference of the main pump and internal leakage of the main pump under different pressures are not considered, so that the control precision is poor. The system comprises a control unit, a pump unit, a data acquisition unit and a load unit, the pump unit comprises a motor and a hydraulic pump, an output shaft of the motor is fixedly connected with the hydraulic pump, the hydraulic pump comprises a plurality of main pumps which are sequentially connected, and the main pumps are communicated with electric proportional valves and pilot pressure sensors and used for forming pilot oil ways of the main pumps; according to the method, the working parameters of the main pump under different outlet pressures and different displacements are obtained, efficiency compensation work is conducted on the main pump by correcting the current of the main pump on the basis, the consistency problem of the main pump is considered, meanwhile, the internal leakage problem of the main pump under different pressures is considered, and the efficiency compensation effect is ensured.

Description

Technical Field

[0001] The present invention relates to an automatic calibration device and method for an electronically controlled main pump and an efficiency compensation method thereof, belonging to the technical field of excavator control. Background Art

[0002] With the continuous iteration of hydraulic systems, electronically controlled positive flow hydraulic systems and fully electronically controlled hydraulic systems are commonly used in medium and large tonnage excavators at present. As the power component of the entire hydraulic system, the electronically controlled main pump plays an extremely important role. Due to differences in manufacturing precision, there are certain differences between different individuals of the main pump even in the same batch. At the same time, as the load pressure increases, the internal leakage of the main pump increases, and the volumetric efficiency further decreases. The above reasons will all cause the corresponding curve of the current and displacement of the main pump to change, resulting in deviation in output flow control and affecting the overall machine efficiency and fuel consumption.

[0003] When the existing hydraulic system controls the electronically controlled main pump, it usually uses the theoretical current displacement curve provided by the manufacturer for power control, without considering the consistency problem of the main pump and the internal leakage problem of the main pump under different pressures, resulting in poor control accuracy and affecting the working effect of the hydraulic system. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide an automatic calibration device and method for an electronically controlled main pump and an efficiency compensation method thereof, so as to solve the problem that when the existing hydraulic control system controls the electronically controlled main pump, it usually uses the theoretical current displacement curve provided by the manufacturer for power control, without considering the consistency problem of the main pump and the internal leakage problem of the main pump under different pressures, resulting in poor control accuracy.

[0005] To solve the above technical problems, the present invention is implemented by the following technical solutions: In the first aspect, the present invention provides an automatic calibration device for an electronically controlled main pump, including a control unit, a pump unit, a data acquisition unit, and a load unit; The pump unit includes a motor and a hydraulic pump. The output shaft of the motor is fixedly connected to the hydraulic pump. The hydraulic pump includes a plurality of main pumps connected in sequence. The main pump is connected to an electro-hydraulic proportional valve and a pilot pressure sensor to form a pilot oil circuit of the main pump; The main pump is connected to the load unit through a flow meter and a pressure sensor to form a load oil circuit of the main pump; A plurality of the electro-hydraulic proportional valves and a plurality of the pressure sensors are electrically connected to the control unit, and a plurality of the flow meters, a plurality of the pressure sensors, and a plurality of the pilot pressure sensors are electrically connected to the data acquisition unit.

[0006] Further, the hydraulic pump is a double hydraulic pump, and the double hydraulic pump includes two of the main pumps.

[0007] Further, the inlet of the hydraulic pump is communicated with the fuel tank, the outlet of the hydraulic pump is communicated with the load unit through the flow meter and the pressure sensor, and the outlet of the load unit is communicated with the fuel tank.

[0008] In a second aspect, the present invention provides an automatic calibration method and an efficiency compensation method for an electronically controlled main pump. Based on the automatic calibration device for an electronically controlled main pump described in the first aspect, the method includes an automatic calibration method and an efficiency compensation method for an electronically controlled main pump. The automatic calibration method for the electronically controlled main pump includes the following steps: Obtain the change curve of the main pump current and displacement and the main pump efficiency model. The efficiency compensation method includes the following steps: According to the target flow rate of the main pump and the change curve of the main pump current and displacement, obtain the target current of the main pump; according to the target displacement of the main pump, the actual outlet pressure, and the main pump efficiency model, obtain the output flow rate of the main pump, and obtain the deviation between the target flow rate of the main pump and the output flow rate of the main pump. Judge the deviation with a preset range, and correct the target current of the main pump according to the judgment result to obtain the output current of the main pump and complete the efficiency compensation work.

[0009] Further, the obtaining of the change curve of the main pump current and displacement specifically includes: Adjust the hydraulic oil temperature of the main pump to the set temperature, adjust the outlet pressure of the main pump to the set pressure, and adjust the speed of the motor to the set speed. Apply a slow current load to the main pump, and within a preset time, load the main pump current from the initial value to the maximum value. After the main pump current remains at the maximum value for the target time, slowly unload the current of the main pump, and unload the main pump current from the maximum value to the initial value at the current loading speed. Repeat the slow current loading and slow current unloading operations multiple times to obtain the main pump current change curve. Obtain the flow rate at the outlet of the main pump in real time, calculate the displacement of the main pump according to the flow rate at the outlet of the main pump, and obtain the main pump displacement change curve. According to the main pump current change curve and the main pump displacement change curve, obtain the relationship diagram of the main pump current and displacement. According to the relationship diagram of the main pump current and displacement, based on preset requirements, take multiple current points in the relationship diagram of the main pump current and displacement and obtain the corresponding displacement points for each current point, and fit the change curve of the main pump current and displacement.

[0010] Further, the obtaining of the main pump efficiency model specifically includes: Adjust the speed of the motor to reach the set speed, and obtain the actual output flow of the main pump at different displacements and different outlet pressures through the controller, the load unit, and the data acquisition unit; Calculate the theoretical output flow according to different displacements, and obtain the volumetric efficiency contour map of the main pump at different displacements and different outlet pressures according to the ratio of the theoretical output flow to the actual output flow; Obtain the main pump efficiency model according to the volumetric efficiency contour map.

[0011] Further, the expression of the efficiency model is as follows: ; In the formula: is the main pump efficiency; is the pressure calculation coefficient; is the displacement calculation coefficient; V is the main pump displacement; 、 is the main pump displacement value; is the main pump output flow; is the main pump speed; is the outlet pressure.

[0012] Further, obtain the main pump target current according to the main pump target flow and the change curve of the main pump current and displacement; obtain the main pump output flow according to the main pump target displacement, the actual outlet pressure, and the main pump efficiency model, specifically including: Calculate the main pump target displacement according to the main pump target flow; Obtain the main pump target current according to the main pump target displacement and the change curve of the main pump current and displacement; Input the main pump target displacement and the actual outlet pressure into the main pump efficiency model to obtain the main pump output flow.

[0013] Further, judge the deviation with the preset range, and correct the main pump target current according to the judgment result to obtain the main pump output current, and complete the efficiency compensation work, specifically including: Step a: If it is judged that the deviation is within the preset range, the work ends and the efficiency compensation work is completed; Step b: If it is judged that the deviation is not within the preset range, use the fuzzy efficiency compensation algorithm to correct the main pump target current to obtain the main pump output current, re-obtain the main pump target displacement according to the main pump output current and the change curve of the main pump current and displacement, re-obtain the main pump output flow according to the main pump target displacement and the actual outlet pressure, and re-obtain the deviation between the main pump target flow and the main pump output flow; Step c: Repeat Step a and Step b until the deviation is within the preset range, the work ends, and the efficiency compensation work is completed.

[0014] In a third aspect, the present invention provides an excavator, including the electronic control main pump automatic calibration device described in the first aspect.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: 1. For the electronic control main pump automatic calibration device, the outlet pressure of the main pump is detected and controlled through a pressure sensor, and the flow rate of the main pump is detected and controlled through a flow meter, so as to obtain the working parameters of the main pump under different outlet pressures and different displacements. On this basis, the main pump is compensated for efficiency by correcting the main pump current. Considering the consistency problem of the main pump and the internal leakage problem of the main pump under different pressures, the effect of efficiency compensation is ensured, and the power control accuracy of the main pump is improved. 2. For the electronic control main pump automatic calibration method and its efficiency compensation method, a practical calibration scheme for the main pump under different outlet pressures and different displacements is provided. The main pump is calibrated under different outlet pressures and different displacements to obtain its working parameters, and the efficiency data image is analyzed. By establishing the relationship between the main pump efficiency, outlet pressure, displacement, and current, a main pump efficiency model is established. On the premise of considering the consistency problem of the main pump and the internal leakage problem of the main pump under different pressures, the output current of the main pump is compensated for efficiency, so as to ensure that the deviation between the target flow rate of the main pump and the output flow rate of the main pump is within the preset range, accurately control the output flow rate of the main pump, improve the working efficiency of the whole machine, and reduce the working fuel consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a system schematic diagram of an electronic control main pump automatic calibration device provided according to an embodiment of the present invention; Figure 2 is a schematic diagram of the main pump current change curve provided according to an embodiment of the present invention; Figure 3 is a schematic diagram of the main pump displacement change curve provided according to an embodiment of the present invention; Figure 4 is a schematic diagram of the relationship between the main pump current and displacement provided according to an embodiment of the present invention; Figure 5 is a volumetric efficiency contour map of the main pump under different displacements and different outlet pressures provided according to an embodiment of the present invention; Figure 6 is a flow schematic diagram of an electronic control main pump automatic calibration method and its efficiency compensation method provided according to an embodiment of the present invention; Figure 7 is a flow schematic diagram of obtaining the change curve of the main pump current and displacement provided according to an embodiment of the present invention; Figure 8 is a flow schematic diagram of obtaining the main pump efficiency model provided according to an embodiment of the present invention; Figure 9It is a schematic flowchart of obtaining a fuzzy efficiency compensation algorithm according to an embodiment of the present invention.

[0017] In the figure: 1. Control unit; 2. Second electro-hydraulic proportional valve; 3. First electro-hydraulic proportional valve; 4. Second pilot pressure sensor; 5. First pilot pressure sensor; 6. Second flowmeter; 7. Double-pump hydraulic pump; 8. Motor; 9. First flowmeter; 10. First pressure sensor; 11. Data acquisition unit; 12. Load unit; 13. Second pressure sensor. Detailed implementation manners

[0018] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and cannot be used to limit the protection scope of the present invention.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0020] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations. Embodiment 1:

[0021] As Figure 1 shown, the present invention provides an automatic calibration device for an electronically controlled main pump, including a control unit 1, a pump unit, a data acquisition unit 11, and a load unit 12; The pump unit includes a motor 8 and a hydraulic pump. The output shaft of the motor 8 is fixedly connected to the hydraulic pump. The hydraulic pump includes a plurality of main pumps connected in sequence. The main pumps are communicated with an electro-hydraulic proportional valve and a pilot pressure sensor to form a pilot oil circuit of the main pumps; The main pumps are communicated with the load unit 12 through a flow meter and a pressure sensor to form a load oil circuit of the main pumps; A plurality of the electro-hydraulic proportional valves and a plurality of the pressure sensors are all electrically connected to the control unit 1. A plurality of the flow meters, a plurality of the pressure sensors and a plurality of the pilot pressure sensors are all electrically connected to the data acquisition unit 11.

[0022] Specifically, the electro-hydraulic proportional valve includes a first electro-hydraulic proportional valve 3 and a second electro-hydraulic proportional valve 2; the pilot pressure sensor includes a first pilot pressure sensor 5 and a second pilot pressure sensor 4; the pressure sensor includes a first pressure sensor 10 and a second pressure sensor 13; the flow meter includes a first flow meter 9 and a second flow meter 6.

[0023] In an embodiment, the hydraulic pump is a double hydraulic pump 7. The double hydraulic pump 7 includes two main pumps, namely main pump one and main pump two. The oil inlet of the hydraulic pump is communicated with a fuel tank. The oil outlet of the hydraulic pump is communicated with the load unit 12 through the flow meter and the pressure sensor. The oil outlet of the load unit 12 is communicated with the fuel tank; Figure 1 The pump 1 in it is the main pump one, and the pump 2 is the main pump two.

[0024] Specifically, the present invention includes a control unit 1, a pump unit, a data acquisition unit 11 and a load unit 12; the pump unit includes a motor 8, a double hydraulic pump 7, a first electro-hydraulic proportional valve 3, a second electro-hydraulic proportional valve 2, a first pilot pressure sensor 5 and a second pilot pressure sensor 4; the first electro-hydraulic proportional valve 3 and the first pilot pressure sensor 5 are communicated with the main pump one to form a pilot oil circuit of the main pump one; the second electro-hydraulic proportional valve 2 and the second pilot pressure sensor 4 are communicated with the main pump two to form a pilot oil circuit of the main pump two; the main pump one, the first flow meter 9, the first pressure sensor 10 and the load unit 12 are communicated to form a load oil circuit of the main pump one; the main pump two, the second flow meter 6, the second pressure sensor 13 and the load unit 12 are communicated to form a load oil circuit of the main pump two; the first electro-hydraulic proportional valve 3, the second electro-hydraulic proportional valve 2, the first pressure sensor 10, the second pressure sensor 13 and the control unit 1 are electrically connected; the first pilot pressure sensor 5, the second pilot pressure sensor 4, the first flow meter 9, the second flow meter 6, the first pressure sensor 10, the second pressure sensor 13 and the data acquisition unit 11 are electrically connected; the output shaft of the motor 8 is fixedly connected to the double hydraulic pump 7; the present invention detects and controls the outlet pressure of the main pump through the pressure sensor, and detects and controls the flow rate of the main pump through the flow meter.

[0025] During specific operation, the present invention first obtains the variation curve of the main pump current and displacement as well as the main pump efficiency model; according to the target flow rate of the main pump and the variation curve of the main pump current and displacement, the target current of the main pump is obtained; according to the target displacement of the main pump, the actual outlet pressure, and the main pump efficiency model, the output flow rate of the main pump is obtained, and the deviation between the target flow rate of the main pump and the output flow rate of the main pump is obtained. The deviation is judged against a preset range, and the target current of the main pump is corrected according to the judgment result to obtain the output current of the main pump, completing the efficiency compensation work; in this embodiment, the main pump can be main pump one or main pump two.

[0026] The present invention detects and controls the outlet pressure of the main pump through a pressure sensor, and detects and controls the flow rate of the main pump through a flow meter, thereby obtaining the operating parameters of the main pump under different outlet pressures and different displacements. On this basis, the main pump is subjected to efficiency compensation work by correcting the main pump current, considering the consistency problem of the main pump and the internal leakage problem of the main pump under different pressures, ensuring the effect of efficiency compensation and improving the power control accuracy of the main pump. Embodiment Two:

[0027] As Figure 6 shown, the present invention provides an automatic calibration method for an electronically controlled main pump and its efficiency compensation method. Based on the electronically controlled main pump automatic calibration device described in Embodiment One, it includes an electronically controlled main pump automatic calibration method and an efficiency compensation method; The electronically controlled main pump automatic calibration method includes the following steps: Obtain the variation curve of the main pump current and displacement as well as the main pump efficiency model; The efficiency compensation method includes the following steps: According to the target flow rate of the main pump and the variation curve of the main pump current and displacement, obtain the target current of the main pump; according to the target displacement of the main pump, the actual outlet pressure, and the main pump efficiency model, obtain the output flow rate of the main pump, and obtain the deviation between the target flow rate of the main pump and the output flow rate of the main pump. Judge the deviation against a preset range, and correct the target current of the main pump according to the judgment result to obtain the output current of the main pump, completing the efficiency compensation work.

[0028] As Figure 7 shown, in one embodiment, the obtaining of the variation curve of the main pump current and displacement specifically includes: Adjust the hydraulic oil temperature of the main pump to the set temperature, adjust the outlet pressure of the main pump to the set pressure, and adjust the speed of the motor to the set speed; Apply a slow current load to the main pump, and within a preset time, load the main pump current from the initial value to the maximum value. After the main pump current remains at the maximum value for the target time, apply a slow current unload to the main pump, and unload the main pump current from the maximum value to the initial value at the current loading speed. Repeat the slow current loading and slow current unloading operations multiple times to obtain the main pump current variation curve; Obtain the flow rate at the outlet of the main pump in real time, calculate the displacement of the main pump according to the flow rate at the outlet of the main pump, and obtain the displacement change curve of the main pump; According to the main pump current change curve and the main pump displacement change curve, obtain the relationship diagram between the main pump current and displacement; According to the relationship diagram between the main pump current and displacement, based on preset requirements, take multiple current points in the relationship diagram between the main pump current and displacement and obtain the displacement points corresponding to each current point, and fit the change curve of the main pump current and displacement.

[0029] Specifically, optionally, in this embodiment, the main pump can be main pump one or main pump two; make the hydraulic oil temperature in the electronic control main pump automatic calibration device reach the set temperature, make the outlet pressure of the main pump reach the set value, make the pilot pressure in the pump unit reach the set value, and make the motor speed reach the set value; slowly load current to the main pump through the control unit, and the current loading setting is as Figure 2 shown. Load the current to the maximum value within a certain time, keep the maximum current stable for the target time, and then unload the current to the initial value according to the current loading speed. Repeat this loading setting multiple times. Optionally, the number of cycles is three; obtain the flow rate at the outlet of the main pump in real time, and convert the flow rate change value during the current loading and unloading period into the main pump displacement change value, and form the displacement change curve of the main pump, as Figure 3 shown; obtain the relationship between the current and displacement of the main pump according to the displacement change curve and the current change curve, as Figure 4 shown; based on preset requirements, take multiple current points between the minimum displacement and the maximum displacement and obtain their corresponding displacements, so as to fit the change curve of the main pump current and displacement. Optionally, the number of current points is eleven. Optionally, the current points taken by this application between the minimum displacement and the maximum displacement are the average values.

[0030] As Figure 8 shown, in an embodiment, the obtaining of the main pump efficiency model specifically includes: Adjust the motor speed to reach the set speed, and obtain the actual output flow rate of the main pump at different displacements and different outlet pressures through the controller, load unit and data acquisition unit; Calculate the theoretical output flow rate according to the displacement, and obtain the volumetric efficiency cloud map of the main pump at different displacements and different outlet pressures according to the ratio of the theoretical output flow rate to the actual output flow rate; According to the volumetric efficiency cloud map, obtain the main pump efficiency model.

[0031] The expression of the efficiency model is as follows: ; In the formula: is the main pump efficiency; is the pressure calculation coefficient; is the displacement calculation coefficient; V is the main pump displacement; 、 is the main pump displacement value; is the main pump output flow rate; is the main pump speed; is the outlet pressure.

[0032] Specifically, make the motor speed reach the set value, and obtain the actual output flow rate of the first main pump at different displacements and different pressures through the control unit, load unit and data acquisition unit; make the motor speed reach the set value, and obtain the actual output flow rate of the second main pump at different displacements and different pressures through the control unit, load unit and data acquisition unit; calculate the theoretical output flow rate according to the displacement, and form the volumetric efficiency contour maps of the first main pump and the second main pump at different displacements and different pressures according to the ratio of the actual output flow rate to the theoretical output flow rate, as Figure 5 shown, Figure 5 the different lines in are different displacements, and the pressure is the outlet pressure.

[0033] An embodiment, obtaining the main pump target current according to the main pump target flow rate and the variation curve of the main pump current with the displacement; obtaining the main pump output flow rate according to the main pump target displacement, the actual outlet pressure and the main pump efficiency model, specifically including: Calculating the main pump target displacement according to the main pump target flow rate; Obtaining the main pump target current according to the main pump target displacement and the variation curve of the main pump current with the displacement; Inputting the main pump target displacement and the actual outlet pressure into the main pump efficiency model to obtain the main pump output flow rate.

[0034] As Figure 9 shown, an embodiment, judging the deviation with a preset range, and correcting the main pump target current according to the judgment result to obtain the main pump output current, and completing the efficiency compensation work, specifically including: Step a: If it is judged that the deviation is within the preset range, the work ends and the efficiency compensation work is completed; Step b: If it is judged that the deviation is not within the preset range, use the fuzzy efficiency compensation algorithm to correct the main pump target current to obtain the main pump output current, re-obtain the main pump target displacement according to the main pump output current and the variation curve of the main pump current with the displacement, re-obtain the main pump output flow rate according to the main pump target displacement and the actual outlet pressure, and re-obtain the deviation between the main pump target flow rate and the main pump output flow rate; Step c: Repeat Step a and Step b until the deviation is within the preset range, the work ends and the efficiency compensation work is completed.

[0035] The present invention provides a practical calibration scheme for the main pump under different outlet pressures and different displacements. By calibrating the main pump under different outlet pressures and different displacements, its working parameters are obtained, and the efficiency data image is analyzed. Based on the relationship among the main pump efficiency, outlet pressure, displacement, and current, a main pump efficiency model is established. On the premise of considering the consistency of the main pump and the internal leakage problem of the main pump under different pressures, efficiency compensation is carried out for the output current of the main pump, so as to ensure that the deviation between the target flow rate of the main pump and the output flow rate of the main pump is within the preset range, accurately control the output flow rate of the main pump, improve the working efficiency of the whole machine, and reduce the working fuel consumption. Embodiment III:

[0036] The present invention provides an excavator, which includes the electronic control main pump automatic calibration device described in Embodiment I.

[0037] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. An automatic calibration device for an electronically controlled main pump, characterized in that: It includes a control unit, a pump unit, a data acquisition unit and a load unit; The pump unit includes a motor and a hydraulic pump, the output shaft of the motor is fixedly connected to the hydraulic pump, the hydraulic pump includes a plurality of main pumps connected in sequence, the main pumps are connected to an electric proportional valve and a pilot pressure sensor to form a pilot oil circuit of the main pump; The main pump is connected to the load unit via a flow meter and a pressure sensor to form a load oil circuit of the main pump; The plurality of electric proportional valves and the plurality of pressure sensors are all electrically connected to the control unit, and the plurality of flow meters, the plurality of pressure sensors and the plurality of pilot pressure sensors are all electrically connected to the data acquisition unit.

2. The automatic calibration device for the electronically controlled main pump according to claim 1 is characterized in that: The hydraulic pump is a double hydraulic pump, and the double hydraulic pump includes two main pumps.

3. The automatic calibration device for the electronically controlled main pump according to claim 1, characterized in that: The oil inlet of the hydraulic pump is communicated with the oil tank, the oil outlet of the hydraulic pump is communicated with the load unit through the flow meter and the pressure sensor, and the oil outlet of the load unit is communicated with the oil tank.

4. An automatic calibration method for an electric-controlled main pump and an efficiency compensation method thereof, based on the automatic calibration device for an electric-controlled main pump according to any one of claims 1 to 3, characterized in that: Including automatic calibration method and efficiency compensation method of electronically controlled main pump; The automatic calibration method of the electronically controlled main pump comprises the following steps: Obtain the change curve of main pump current and displacement and the main pump efficiency model; The efficiency compensation method comprises the following steps: The target current of the main pump is obtained according to the target flow of the main pump and the change curve of the main pump current and displacement; the output flow of the main pump is obtained according to the target displacement of the main pump, the actual outlet pressure and the main pump efficiency model, and the deviation between the target flow of the main pump and the output flow of the main pump is obtained, the deviation is judged with a preset range, and the target current of the main pump is corrected according to the judgment result to obtain the output current of the main pump and complete the efficiency compensation work.

5. The automatic calibration method of the electric control main pump and the efficiency compensation method thereof according to claim 4, characterized in that: The obtaining of the variation curve of the main pump current and displacement specifically includes: Adjust the hydraulic oil temperature of the main pump to the set temperature, adjust the outlet pressure of the main pump to the set pressure, and adjust the motor speed to the set speed; Slowly load the main pump with current, load the main pump current from the initial value to the maximum value within a preset time, and after the main pump current maintains the maximum value for a target time, slowly unload the main pump with current, unload the main pump current from the maximum value to the initial value according to the current loading speed, repeat the slow current loading and slow current unloading operations multiple times, and obtain the main pump current change curve; The flow rate at the outlet of the main pump is obtained in real time, the displacement of the main pump is calculated according to the flow rate at the outlet of the main pump, and a displacement change curve of the main pump is obtained; According to the main pump current variation curve and the main pump displacement variation curve, a relationship diagram between the main pump current and the displacement is obtained; According to the relationship diagram between the main pump current and the displacement, multiple current points are taken in the relationship diagram between the main pump current and the displacement based on preset requirements and the displacement points corresponding to each current point are obtained to fit the variation curve of the main pump current and the displacement.

6. The automatic calibration method of the electric control main pump and the efficiency compensation method thereof according to claim 4, characterized in that: The obtaining of the main pump efficiency model specifically includes: Adjust the motor speed to the set speed, and obtain the actual output flow of the main pump at different displacements and different outlet pressures through the controller, load unit and data acquisition unit; Calculate the theoretical output flow rate according to the displacement, and obtain the volumetric efficiency cloud diagram of the main pump at different displacements and different outlet pressures according to the ratio of the theoretical output flow rate to the actual output flow rate; According to the volumetric efficiency cloud diagram, the main pump efficiency model is obtained.

7. The automatic calibration method of the electric-controlled main pump and the efficiency compensation method thereof according to claim 6, characterized in that: The expression of the efficiency model is as follows: ； Where: Main pump efficiency; is the pressure calculation coefficient; is the displacement calculation coefficient; V Main pump displacement; 、 Is the displacement value of the main pump; Output flow of main pump; Main pump speed; is the outlet pressure.

8. The automatic calibration method of the electric-controlled main pump and the efficiency compensation method thereof according to claim 4, characterized in that: The main pump target current is obtained according to the main pump target flow rate and the change curve of the main pump current and displacement; According to the target displacement of the main pump, the actual outlet pressure and the main pump efficiency model, the output flow of the main pump is obtained, specifically including: Calculate the target displacement of the main pump according to the target flow of the main pump; Obtaining a main pump target current according to the main pump target displacement and a curve of the change of the main pump current and displacement; The target displacement and actual outlet pressure of the main pump are input into the main pump efficiency model to obtain the output flow of the main pump.

9. The automatic calibration method of the electric-controlled main pump and the efficiency compensation method thereof according to claim 4, characterized in that: The deviation is judged with the preset range, and the target current of the main pump is corrected according to the judgment result to obtain the output current of the main pump and complete the efficiency compensation work, specifically including: Step a: If the deviation is judged to be within the preset range, the work is completed and the efficiency compensation work is completed; Step b: if it is determined that the deviation is not within the preset range, the main pump target current is corrected using a fuzzy efficiency compensation algorithm to obtain the main pump output current, the main pump target displacement is re-obtained according to the main pump output current and the change curve of the main pump current and displacement, the main pump output flow is re-obtained according to the main pump target displacement and the actual outlet pressure, and the deviation between the main pump target flow and the main pump output flow is re-obtained; Step c: Repeat steps a and b until the deviation is within the preset range. The work is completed and the efficiency compensation work is completed.

10. An excavator, characterized in that: It comprises the automatic calibration device for the electrically controlled main pump as described in any one of claims 1 to 3.

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