Electric excavator system and control method

Abstract

The application belongs to the technical field of excavators, and discloses an electric excavator system and a control method. The control method comprises the following steps: acquiring the pump body pressure and the pilot pressure of each plunger pump; determining the required flow of each plunger pump according to the pump body pressure and the pilot pressure; determining the initial calculation speed of the motor according to the required flow of each plunger pump; determining the calculation speed of the motor according to the initial calculation speed; determining the speed adjustment strategy of the motor according to the calculation speed, and controlling the motor to adjust the speed according to the speed adjustment strategy; determining the displacement adjustment strategy of each plunger pump according to the calculation speed and the required flow of each plunger pump, and controlling the corresponding plunger pump to adjust the displacement according to the displacement adjustment strategy. The comprehensive efficiency of the plunger pump and the motor is optimal under the condition that the flow of each plunger pump is unchanged, and the energy consumption is lower and the endurance time is longer under the same working condition.

Description

Technical Field

[0001] This invention relates to the field of excavator technology, and more particularly to an electric excavator system and control method. Background Technology

[0002] With increasing societal emphasis on environmental protection, traditional excavators are no longer suitable for new environmental requirements; among them, electric excavators are gradually becoming a new development direction.

[0003] Current pure electric excavators suffer from short operating range due to the large weight and high cost of their power batteries. Existing technologies largely follow the control strategies of traditional diesel engines, maintaining a constant operating speed and adjusting power solely by regulating the main pump displacement. This severely limits the efficiency adjustment of the electric excavator's power system, leading to energy waste and increased overall vehicle energy consumption. Summary of the Invention

[0004] The main objective of this invention is to provide an electric excavator system and control method, which aims to solve the problem of the limited efficiency of the power system of electric excavators.

[0005] To achieve the above objectives, the present invention provides a control method for an electric excavator system, the electric excavator system including a motor and a plurality of piston pumps connected to the motor for driving;

[0006] The control method includes:

[0007] Obtain the pump body pressure and pilot pressure of each of the plunger pumps;

[0008] The required flow rate of each plunger pump is determined based on the pump body pressure and the pilot pressure.

[0009] The initial calculated speed of the motor is determined based on the required flow rate of each of the aforementioned plunger pumps;

[0010] The calculated speed of the motor is determined based on the initial calculated speed;

[0011] Based on the calculated rotational speed, a rotational speed adjustment strategy for the motor is determined, and the rotational speed of the motor is adjusted according to the rotational speed adjustment strategy.

[0012] Based on the calculated rotational speed and the required flow rate of each plunger pump, a displacement adjustment strategy for each plunger pump is determined, and the corresponding plunger pump is controlled to adjust its displacement according to the displacement adjustment strategy.

[0013] Optionally, determining the initial speed of the motor based on the required flow rate of each of the plunger pumps includes:

[0014] Select the maximum value among the multiple required flow rates as the reference flow rate;

[0015] The initial rotational speed is calculated based on the reference flow rate.

[0016] Optionally, calculating the initial rotational speed based on the reference flow rate includes:

[0017] Obtain the set displacement of the plunger pump corresponding to the reference flow rate;

[0018] Select the maximum value among the specified displacements as the reference displacement;

[0019] The initial rotational speed is calculated based on the reference flow rate and the reference displacement.

[0020] Optionally, determining the calculated speed of the motor based on the initial calculated speed includes:

[0021] Determine the weight adjustment coefficient;

[0022] Obtain the limiting parameters of the motor;

[0023] The calculated speed of the motor is determined based on the initial calculated speed, the weight adjustment coefficient, and the limiting parameters.

[0024] Optionally, determining the weight adjustment coefficient includes:

[0025] Obtain the starting pressure and maximum pressure of the system composed of multiple plunger pumps;

[0026] The average pressure of each plunger pump is determined based on the pump body pressure of each plunger pump.

[0027] The weighting adjustment coefficient is determined based on the average pressure and the starting pressure.

[0028] Optionally, determining the weighting adjustment coefficient based on the average pressure and the starting pressure includes:

[0029] When the average pressure is greater than the starting pressure, the weight adjustment coefficient is determined to be a first fixed value;

[0030] When the average pressure is less than the starting pressure, the weighting adjustment coefficient is calculated and determined based on the average pressure, the starting pressure, and the maximum pressure.

[0031] Optionally, the limiting parameters include the limiting torque and limiting power of the motor.

[0032] Optionally, determining the motor speed adjustment strategy based on the calculated speed, and controlling the motor speed adjustment according to the speed adjustment strategy, includes:

[0033] Obtain the current speed of the motor;

[0034] At the current rotational speed, a preset rotational speed step value is sequentially increased to obtain multiple process target rotational speeds between the current rotational speed and the calculated rotational speed;

[0035] Based on multiple target speeds for the process, the motor speed is controlled to gradually change from the current speed to the calculated speed.

[0036] Optionally, determining the displacement adjustment strategy for each plunger pump based on the calculated rotational speed and the required flow rate of each plunger pump, and controlling the corresponding plunger pump to adjust its displacement according to each displacement adjustment strategy, includes:

[0037] Based on the calculated rotational speed, the multiple process target rotational speeds, and the corresponding required flow rate of the plunger pump, determine and obtain the calculated displacement of the plunger pump and the multiple process target displacements;

[0038] Based on the calculated displacement and multiple process target displacements, the calculated current and multiple target currents of the solenoid valve of the plunger pump are determined.

[0039] Based on the multiple target currents, the current of the solenoid valve of the plunger pump is gradually changed to the calculated current.

[0040] The present invention also provides an electric excavator system, comprising:

[0041] Multiple plunger pumps, each of which is equipped with a solenoid valve;

[0042] An electric motor for controlling the rotational speed of the plurality of said plunger pumps; and,

[0043] A control device electrically connected to a plurality of the piston pumps and the motor, the control device including a memory and a processor and a control program for an electric excavator system stored in the memory and executable on the processor, the control program for the electric excavator system being configured to implement the steps of the control method for the electric excavator system as claimed in any one of claims 1 to 9.

[0044] In the control method of the electric excavator system provided by the present invention, multiple plunger pumps are connected in series and controlled by the same motor. The initial speed is obtained by comprehensively considering the required flow of multiple plunger pumps, and the calculated speed is obtained by adjusting the initial speed. The calculated speed can satisfy the high-efficiency operation of the motor and also ensure that each plunger pump is in the high-efficiency operating range with a large displacement. Under the condition that the flow of each plunger pump remains constant, the combined efficiency of the plunger pumps and the motor is optimized by controlling the speed and solenoid valve. Under the same working conditions, the energy consumption is lower and the endurance is longer. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the structure of the electric excavator system provided in an embodiment of the present invention;

[0046] Figure 2 This is a flowchart of the electric excavator system control method provided in an embodiment of the present invention;

[0047] Figure 3 yes Figure 2 A flowchart of an embodiment of the control method for a medium-sized electric excavator system.

[0048] Explanation of icon numbers:

[0049]

[0050]

[0051] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0053] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0054] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0055] With increasing societal emphasis on environmental protection, traditional excavators are no longer suitable for new environmental requirements; among them, electric excavators are gradually becoming a new development direction.

[0056] Most current pure electric excavators directly adopt the control strategy of traditional diesel engines. The speed remains constant during operation, and the power adjustment relies solely on the adjustment of the main pump displacement. This results in a large limitation in the efficiency adjustment of the electric excavator's power system, causing some energy waste, increasing the overall energy consumption of the vehicle, and shortening the vehicle's range. In order to ensure the normal use of pure electric excavators, it is necessary to increase the weight of the battery, which further increases the overall weight and cost of the vehicle.

[0057] Please see Figure 1 The present invention provides an electric excavator system 100, including a plurality of plunger pumps 1 and a motor 2; each of the plunger pumps 1 is provided with a solenoid valve; the motor 2 is used to control the rotational speed of the plurality of plunger pumps 1.

[0058] In the electric excavator system 100 provided by the present invention, a single motor 2 is used to control multiple plunger pumps 1 in series. The multiple plunger pumps 1 supply oil to different actuators. Since the different actuators have different working states, their required flow rates are inconsistent. By comprehensively considering the working efficiency of the motor 2 and the multiple plunger pumps 1, it is convenient to control the working efficiency of the entire system.

[0059] It should be noted that, during the operation of the plunger pump, under the condition of a certain flow rate, the displacement of the plunger pump and the speed of the motor are inversely proportional. The displacement and speed affect the working efficiency of the motor 2 and the plunger pump 1, respectively. When the displacement increases, the efficiency of the plunger pump 1 increases, while when the speed increases, the efficiency of the motor 2 increases. Therefore, it is necessary to simultaneously ensure that the motor 2 is in the largest speed range and that the displacements of multiple plunger pumps 1 are all in a large range to maximize the working efficiency of the entire system.

[0060] It should be noted that in this embodiment, the motor 2 simultaneously drives and controls the rotational speed of multiple plunger pumps 1, so that the plunger pumps generate corresponding flow rates and displacements.

[0061] Furthermore, the electric excavator system 100 also includes multiple pressure sensors 3, each corresponding to one of the multiple plunger pumps 1, to facilitate the detection of the pressure of the plunger pumps.

[0062] On the other hand, the electric excavator system 100 also includes a control device that is electrically connected to the plurality of piston pumps 1 and the motor 2, for controlling the opening and closing of the solenoid valves of the piston pumps 1 and the rotation of the motor 2.

[0063] Furthermore, the control device includes a memory, a processor, and a control program for the electric excavator system stored in the memory. The processor executes the control program for the electric excavator system to implement the following control method for the electric excavator system:

[0064] Obtain the pump body pressure and pilot pressure of each of the plunger pumps;

[0065] The required flow rate of each plunger pump is determined based on the pump body pressure and the pilot pressure.

[0066] The initial calculated speed of the motor is determined based on the required flow rate of each of the aforementioned plunger pumps;

[0067] The calculated speed of the motor is determined based on the initial calculated speed;

[0068] Based on the calculated rotational speed, a rotational speed adjustment strategy for the motor is determined, and the rotational speed of the motor is adjusted according to the rotational speed adjustment strategy.

[0069] Based on the calculated rotational speed and the required flow rate of each plunger pump, a displacement adjustment strategy for each plunger pump is determined, and the corresponding plunger pump is controlled to adjust its displacement according to the displacement adjustment strategy.

[0070] Optionally, determining the initial speed of the motor based on the required flow rate of each of the plunger pumps includes:

[0071] Select the maximum value among the multiple required flow rates as the reference flow rate;

[0072] The initial rotational speed is calculated based on the reference flow rate.

[0073] Optionally, calculating the initial rotational speed based on the reference flow rate includes:

[0074] Obtain the set displacement of the plunger pump corresponding to the reference flow rate;

[0075] Select the maximum value among the specified displacements as the reference displacement;

[0076] The initial rotational speed is calculated based on the reference flow rate and the reference displacement.

[0077] Optionally, determining the calculated speed of the motor based on the initial calculated speed includes:

[0078] Determine the weight adjustment coefficient;

[0079] Obtain the limiting parameters of the motor;

[0080] The calculated speed of the motor is determined based on the initial calculated speed, the weight adjustment coefficient, and the limiting parameters.

[0081] Optionally, determining the weight adjustment coefficient includes:

[0082] Obtain the starting pressure and maximum pressure of the system composed of multiple plunger pumps;

[0083] The average pressure of each plunger pump is determined based on the pump body pressure of each plunger pump.

[0084] The weighting adjustment coefficient is determined based on the average pressure and the starting pressure.

[0085] Optionally, determining the weighting adjustment coefficient based on the average pressure and the starting pressure includes:

[0086] When the average pressure is greater than the starting pressure, the weight adjustment coefficient is determined to be a first fixed value;

[0087] When the average pressure is less than the starting pressure, the weighting adjustment coefficient is calculated and determined based on the average pressure, the starting pressure, and the maximum pressure.

[0088] Optionally, the limiting parameters include the limiting torque and limiting power of the motor.

[0089] Optionally, determining the motor speed adjustment strategy based on the calculated speed, and controlling the motor speed adjustment according to the speed adjustment strategy, includes:

[0090] Obtain the current speed of the motor;

[0091] At the current rotational speed, a preset rotational speed step value is sequentially increased to obtain multiple process target rotational speeds between the current rotational speed and the calculated rotational speed;

[0092] Based on multiple target speeds for the process, the motor speed is controlled to gradually change from the current speed to the calculated speed.

[0093] Optionally, determining the displacement adjustment strategy for each plunger pump based on the calculated rotational speed and the required flow rate of each plunger pump, and controlling the corresponding plunger pump to adjust its displacement according to each displacement adjustment strategy, includes:

[0094] Based on the calculated rotational speed, the multiple process target rotational speeds, and the corresponding required flow rate of the plunger pump, determine and obtain the calculated displacement of the plunger pump and the multiple process target displacements;

[0095] Based on the calculated displacement and multiple process target displacements, the calculated current and multiple target currents of the solenoid valve of the plunger pump are determined.

[0096] Based on the multiple target currents, the current of the solenoid valve of the plunger pump is gradually changed to the calculated current.

[0097] In the control method of the electric excavator system provided by the present invention, multiple plunger pumps 1 are connected in series and controlled by the same motor 2. The initial speed is calculated by comprehensively considering the required flow of multiple plunger pumps 1. The initial speed is adjusted so that it can meet the high-efficiency operation of the motor and also ensure that each plunger pump 1 is in a high-efficiency operating range with a large displacement. Under the condition that the flow of each plunger pump 1 remains constant, the combined efficiency of the plunger pump 1 and the motor 2 is optimized by controlling the speed and solenoid valve. Under the same working conditions, the energy consumption is lower and the endurance is longer.

[0098] Please see Figures 2 to 3 The present invention also provides a control method for an electric excavator system, the control method comprising:

[0099] S10. Obtain the pump body pressure and pilot pressure of each plunger pump;

[0100] The multiple plunger pumps 1 supply oil to different actuators, resulting in different pump body pressures on the multiple plunger pumps 1. Consequently, the required working states of the different plunger pumps 1 are different. Therefore, when controlling the electric excavator system, it is necessary to first obtain the working status of each plunger pump 1 at this time, and determine the state of each plunger pump 1 at this time based on the actual pump body pressure and pilot pressure.

[0101] It should be noted that the pump body pressure is obtained through a pressure sensor; while the pilot pressure is a preset reference value for each of the plunger pumps 1. When the electric excavator is working, the pressure values ​​generated by different actuators are different, which makes the pump body pressure generated on each of the plunger pumps 1 also different. The pilot pressure is combined to facilitate accurate control of the state of the plunger pump 1 in the future.

[0102] S20. Determine the required flow rate of each plunger pump based on the pump body pressure and the pilot pressure;

[0103] After obtaining the pump body pressure and the pilot pressure, the required flow rate for the plunger pump 1 to complete a series of actions can be determined to ensure that the required flow rate can respond to changes in the pump body pressure.

[0104] It should be noted that, in this embodiment, the required flow rate can be correlated with the pump body pressure and pilot pressure based on the actual test results, as long as the required flow rate on each plunger pump 1 can be determined based on the pump body pressure.

[0105] S30. Determine the initial speed of the motor based on the required flow rate of each plunger pump;

[0106] Once the required flow rate of each plunger pump 1 is obtained, an initial calculated speed of one of the motors 2 can be determined based on the multiple required flow rates, so as to control the motor 2 according to the initial calculated speed.

[0107] It should be noted that the flow rate and rotation speed satisfy the following relationship:

[0108] n = Q / q

[0109] Where n is the rotational speed, Q is the flow rate, and q is the displacement.

[0110] S40. Determine the calculated speed of the motor based on the initial calculated speed;

[0111] Since the required flow rates of the multiple plunger pumps 1 are different, their actual required speeds are different. In order to improve the control efficiency of the motor 2 in controlling the multiple plunger pumps 1, the initial calculated speed needs to be adjusted so that the motor 2 can meet the efficiency requirements of the multiple plunger pumps 1 while also operating within a high-efficiency speed range.

[0112] It should be noted that for electric motors, efficiency is related to both speed and torque. In the operating range where torque is high and speed is low, the efficiency is high.

[0113] S50. Based on the calculated rotational speed, determine the motor speed adjustment strategy, and control the motor to adjust its rotational speed according to the rotational speed adjustment strategy;

[0114] After obtaining the adjusted calculated speed, the final control target that the motor 2 needs to achieve can be obtained based on the calculated speed. The motor is then controlled according to a preset adjustment strategy, so that the motor 2 can still operate in a high-efficiency range when controlling multiple plunger pumps 1 at the same time.

[0115] S60. Based on the calculated rotational speed and the required flow rate of each plunger pump, determine the displacement adjustment strategy of each plunger pump, and control the corresponding plunger pump to adjust the displacement according to each displacement adjustment strategy.

[0116] In this process, the rotational speed of each plunger pump 1 has been obtained, and the required flow rate under the corresponding operating condition has also been determined. Based on this, the displacement of each plunger pump 1 can be obtained. Then, according to the different displacement requirements of each plunger pump 1, the solenoid valve of the plunger pump 1 can be adjusted accordingly, so that each plunger pump 1 is in the working range with the highest working efficiency.

[0117] It should be noted that for plunger pumps, the higher the pressure and the higher the displacement, the higher the pump's working efficiency. Therefore, given a fixed pressure for each plunger pump, the overall efficiency of the multiple plunger pumps 1 can be maximized through displacement control.

[0118] In the control method of the electric excavator system provided by the present invention, multiple plunger pumps 1 are connected in series and controlled by the same motor 2. The initial speed is calculated by comprehensively considering the required flow of multiple plunger pumps 1. The initial speed is adjusted so that it can meet the high-efficiency operation of the motor and also ensure that each plunger pump 1 is in a high-efficiency operating range with a large displacement. Under the condition that the flow of each plunger pump 1 remains constant, the combined efficiency of the plunger pump 1 and the motor 2 is optimized by controlling the speed and solenoid valve. Under the same working conditions, the energy consumption is lower and the endurance is longer.

[0119] Furthermore, step S30 includes:

[0120] S31. Select the maximum value among the multiple required flow rates as the reference flow rate;

[0121] In this embodiment, without considering the displacement, the larger the required flow rate, the faster the rotation speed. Based on the relationship between flow rate, displacement, and rotation speed, a larger calculated rotation speed can be achieved. Based on this, the working efficiency of the motor 2 can be improved while meeting the pump body requirements.

[0122] S32. Calculate the initial rotational speed based on the reference flow rate.

[0123] After obtaining the maximum value as a reference flow rate, the initial rotational speed is calculated using the maximum value.

[0124] Specifically, step S32 includes:

[0125] S321. Obtain the set displacement of the plunger pump corresponding to the reference flow rate;

[0126] After obtaining the reference flow rate, the corresponding plunger pump 1 has a set displacement. In order to facilitate the calculation of the required speed of the plunger pump 1 at this time, it is necessary to obtain the set displacement of the plunger pump 1.

[0127] S322. Select the maximum value among the set displacements as the reference displacement;

[0128] Since the larger the displacement, the higher the working efficiency of the plunger pump 1, and the variation range of pump efficiency is much greater than that of motor efficiency, considering the highest system efficiency, it is believed that making the pump work under a large displacement condition can improve system efficiency. Therefore, the maximum value in the set displacement needs to be used as the reference displacement for calculating the speed.

[0129] S323. Calculate the initial rotational speed based on the reference flow rate and the reference displacement.

[0130] Taking the maximum reference flow rate ensures a higher motor speed, thus maximizing the efficiency of motor 2. Simultaneously, using the maximum displacement as the reference displacement ensures higher pump efficiency, thereby improving the overall system efficiency.

[0131] On the other hand, step S40 includes:

[0132] S41. Determine the weight adjustment coefficient;

[0133] After obtaining the initial calculated speed, directly controlling the motor to rotate according to the initial calculated speed may damage the motor and fail to meet the normal operation requirements of the motor. Therefore, it is necessary to perform weighted control on the motor to ensure its normal operation.

[0134] S42. Obtain the limiting parameters of the motor;

[0135] By obtaining the limiting parameters of the motor 2, the base value for subsequent weighting can be determined.

[0136] S43. Determine the calculated speed of the motor based on the initial calculated speed, the weight adjustment coefficient, and the limiting parameters.

[0137] Based on the limiting parameters and the initial calculated speed, the initial calculated speed is weighted to the base value brought by the limiting parameters in a weighted manner, which can ensure both the efficient operation of the motor 2 and the safety of the motor 2.

[0138] Specifically, step S41 includes:

[0139] S411. Obtain the starting pressure and maximum pressure of the system composed of multiple plunger pumps;

[0140] The system consisting of the plunger pump 1 ensures normal operation of the entire system by adjusting the starting pressure and the maximum pressure. Therefore, before controlling the motor, the weighting needs to be determined based on the pressure on the plunger pump 1.

[0141] S412. Determine the average pressure of each plunger pump based on the pump body pressure of each plunger pump.

[0142] The weight of the initial calculated speed is determined based on the average pressure on each of the plunger pumps 1, thereby ensuring that the initial calculated speed can adapt to the average pressure on the plunger pumps 1.

[0143] S413. Determine the weighting adjustment coefficient based on the average pressure and the starting pressure.

[0144] In this embodiment, the weight of the initial speed of the motor 2 is determined based on the relationship between the average pressure and the starting pressure, so as to ensure that the normal operation of the multiple plunger pumps can be guaranteed, while the high-efficiency operation of the motor can be satisfied.

[0145] Specifically, step S413 includes:

[0146] S4131. When the average pressure is greater than the starting pressure, the weight adjustment coefficient is determined to be a first fixed value.

[0147] S4132. When the average pressure is less than the starting pressure, the weighting adjustment coefficient is calculated and determined based on the average pressure, the starting pressure, and the maximum pressure.

[0148] Specifically, the average pressure, the starting pressure, and the maximum pressure are used to calculate and determine the weighting adjustment coefficient, which satisfies the following relationship:

[0149] k=(p avg -p sta ) / (p max -p sta )

[0150] Wherein, k is the weight adjustment coefficient, and p avg For the average pressure, p sta To adjust the pressure, the p max This represents the maximum pressure.

[0151] Furthermore, the starting pressure satisfies the following relationship:

[0152] p sta =tor / (2q) max )

[0153] Wherein, the q max The reference displacement, which is also the reference flow rate, corresponds to the maximum value of the set drift of plunger pump 1.

[0154] In addition, the limiting parameters include the limiting torque and limiting power of the motor.

[0155] Specifically, in this embodiment, step S43 satisfies the following relationship:

[0156] n c= k*(pow / tor) + (1-k)n c’

[0157] Wherein, n c For calculating rotational speed, k is a weighting adjustment coefficient, pow is the power limit, tor is the torque limit, and n... c’ This is the initial calculated rotational speed.

[0158] In addition, in this embodiment, when the average pressure is less than the starting pressure, k is determined based on the average pressure;

[0159] When the average pressure is greater than the starting pressure, k is zero, making the calculated rotational speed equal to the initial calculated rotational speed.

[0160] On the other hand, step S50 includes:

[0161] S51. Obtain the current speed of the motor;

[0162] S52. Based on the current rotational speed, a preset rotational speed step value is sequentially increased to obtain multiple process target rotational speeds between the current rotational speed and the calculated rotational speed;

[0163] S53. Based on the multiple process target speeds, control the motor speed to gradually change from the current speed to the calculated speed.

[0164] In this embodiment, the motor 2 is controlled to change from its current speed to the calculated speed by stepping, thereby controlling the rate of change of the motor 2's speed, ensuring the efficiency of the motor 2's change, and avoiding increased energy consumption caused by direct adjustment.

[0165] Furthermore, step S60 includes:

[0166] S61. Based on the calculated rotational speed, multiple process target rotational speeds, and the corresponding required flow rate of the plunger pump, determine and obtain the calculated displacement and multiple process target displacements corresponding to the plunger pump;

[0167] Specifically, based on the calculated rotational speed and multiple target rotational speeds, the target displacement corresponding to each rotational speed can be obtained.

[0168] S62. Based on the calculated displacement and multiple process target displacements, determine the calculated current and multiple target currents of the solenoid valve of the plunger pump.

[0169] The solenoid valve of the plunger pump 1 can be controlled according to the target displacement. Therefore, the corresponding target current is obtained so that the plunger pump 1 adjusts the displacement to the target displacement.

[0170] S63. Based on the multiple target currents, control the current of the solenoid valve of the plunger pump to be gradually changed to the calculated current.

[0171] In this embodiment, the speed of the motor 2 is adjusted step by step, and the solenoid valve of the plunger pump 1 is also adjusted step by step in sync, so as to achieve the joint adjustment of the two to meet the required flow rate and at the same time ensure the overall working efficiency of the entire system.

[0172] It should be noted that the target current and the target displacement satisfy the following relationship:

[0173] I = I min +(q 1r -q min (I) max -I min ) / (q max -q min )

[0174] Wherein, I is the target current, I min For the minimum current of the solenoid valve, I max For the maximum current of the solenoid valve, q min For the minimum displacement of the corresponding plunger pump, q max For reference displacement, q 1r Target displacement.

[0175] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A control method for an electric excavator system, characterized in that, The electric excavator system includes a motor and multiple piston pumps connected to the motor for driving. The control method includes: Obtain the pump body pressure and pilot pressure of each of the plunger pumps; The required flow rate of each plunger pump is determined based on the pump body pressure and the pilot pressure. The initial calculated speed of the motor is determined based on the required flow rate of each of the aforementioned plunger pumps; The calculated speed of the motor is determined based on the initial calculated speed; Based on the calculated rotational speed, a rotational speed adjustment strategy for the motor is determined, and the rotational speed of the motor is adjusted according to the rotational speed adjustment strategy. Based on the calculated rotational speed and the required flow rate of each plunger pump, a displacement adjustment strategy for each plunger pump is determined, and the corresponding plunger pump is controlled to adjust its displacement according to the displacement adjustment strategy. The step of determining the motor speed adjustment strategy based on the calculated speed, and controlling the motor speed adjustment according to the speed adjustment strategy, includes: Obtain the current speed of the motor; At the current rotational speed, a preset rotational speed step value is sequentially increased to obtain multiple process target rotational speeds between the current rotational speed and the calculated rotational speed; Based on multiple process target speeds, the motor speed is controlled to gradually change from the current speed to the calculated speed; The step of determining the displacement adjustment strategy for each plunger pump based on the calculated rotational speed and the required flow rate of each plunger pump, and controlling the corresponding plunger pump to adjust its displacement according to each displacement adjustment strategy, includes: Based on the calculated rotational speed, the multiple process target rotational speeds, and the corresponding required flow rate of the plunger pump, determine and obtain the calculated displacement of the plunger pump and the multiple process target displacements; Based on the calculated displacement and multiple process target displacements, the calculated current and multiple target currents of the solenoid valve of the plunger pump are determined. Based on the multiple target currents, the current of the solenoid valve of the plunger pump is gradually changed to the calculated current.

2. The control method for the electric excavator system according to claim 1, characterized in that, The step of determining the initial speed of the motor based on the required flow rate of each of the plunger pumps includes: Select the maximum value among the multiple required flow rates as the reference flow rate; The initial rotational speed is calculated based on the reference flow rate.

3. The control method for the electric excavator system according to claim 2, characterized in that, The step of calculating the initial rotational speed based on the reference flow rate includes: Obtain the set displacement of the plunger pump corresponding to the reference flow rate; Select the maximum value among the specified displacements as the reference displacement; The initial rotational speed is calculated based on the reference flow rate and the reference displacement.

4. The control method for the electric excavator system according to claim 1, characterized in that, The step of determining the calculated speed of the motor based on the initial calculated speed includes: Determine the weight adjustment coefficient; Obtain the limiting parameters of the motor; The calculated speed of the motor is determined based on the initial calculated speed, the weight adjustment coefficient, and the limiting parameters; The determination of the weight adjustment coefficient includes: Obtain the starting pressure and maximum pressure of the system composed of multiple plunger pumps; The average pressure of each plunger pump is determined based on the pump body pressure of each plunger pump. The weighting adjustment coefficient is determined based on the average pressure and the starting pressure. The weight adjustment coefficients satisfy the following relationship: Among them, the For weight adjustment coefficients, the For average pressure, the To adjust the pressure, the aforementioned This represents the maximum pressure.

5. The control method for the electric excavator system according to claim 4, characterized in that, The step of determining the weighting adjustment coefficient based on the average pressure and the starting pressure includes: When the average pressure is greater than the starting pressure, the weight adjustment coefficient is determined to be a first fixed value; When the average pressure is less than the starting pressure, the weighting adjustment coefficient is calculated and determined based on the average pressure, the starting pressure, and the maximum pressure.

6. The control method for the electric excavator system according to claim 4, characterized in that, The limiting parameters include the limiting torque and limiting power of the motor.

7. An electric excavator system, characterized in that, include: Multiple plunger pumps, each of which is equipped with a solenoid valve; An electric motor is used to control the rotational speed of the multiple piston pumps; as well as, A control device electrically connected to a plurality of the piston pumps and the motor, the control device including a memory and a processor and a control program for an electric excavator system stored in the memory and executable on the processor, the control program for the electric excavator system being configured to implement the steps of the control method for the electric excavator system as claimed in any one of claims 1 to 6.

Images