A control system and method suitable for excavator engine and ISG motor

Abstract

This invention discloses a control system and method applicable to excavator engines and ISG motors. The control system includes an engine, an ISG motor, a hydraulic pump, a sensor module, and a main controller. The sensor module collects the pressure and displacement of the hydraulic pump, as well as the rotational speed of the ISG motor and the engine. The main controller generates a first compensation torque and a second compensation torque based on the hydraulic pump pressure and displacement, respectively. It generates a third compensation torque and a fourth compensation torque based on the engine rotational speed and the ISG motor rotational speed. Based on the change in engine rotational speed, a fifth compensation torque is calculated using a PI control algorithm. The maximum value among the first, second, third, and fourth compensation torques is selected and summed with the fifth compensation torque to serve as the target compensation torque for the ISG motor, controlling the ISG motor to perform torque compensation for the engine. This invention controls the ISG motor to perform torque compensation for the engine, enabling the engine speed to quickly return to the optimal fuel consumption range and reducing operating fuel consumption.

Description

Technical Field

[0001] This invention belongs to the field of new energy engineering machinery, specifically relating to a control system and method applicable to excavator engines and ISG motors. Background Technology

[0002] Excavators are multi-purpose construction machinery, frequently used for digging, leveling, loading, and crushing operations. Their work cycles are highly cyclical, and the external loads are complex and variable. Due to these varying loads, the engine speed fluctuates constantly, causing it to frequently oscillate between its high-efficiency and low-efficiency zones. Under these transient operating conditions, fuel consumption increases significantly. Increased fuel consumption raises the customer's operating costs.

[0003] To achieve energy savings, hybrid excavators incorporate ISG motors. The excavator is driven by a coaxial parallel connection of the engine and the ISG motor. The ISG motor can operate in two modes: drive and generator. In drive mode, it assists the engine to improve its load response; in generator mode, excess engine power charges the battery, which then powers excavator accessories such as the electric water pump, fan, and electric swing arm. Because of the coaxial parallel connection, the engine and motor maintain the same speed. The ISG motor's auxiliary drive offers better speed regulation compared to engine-only drive, and its high control precision and fast response can mitigate the impact of sudden load changes on the engine.

[0004] Currently, constant engine speed control is generally achieved by controlling the engine throttle through a PLC, stepper motor, and rack and pinion mechanism based on the engine speed difference. The drawbacks are long response time and a lack of consideration for mitigating load disturbances. For power systems with variable loads, this results in the engine spending a relatively long time in its inefficient range. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a control system and method applicable to excavator engines and ISG motors, which controls the ISG motor to perform torque compensation on the engine, enabling the engine speed to quickly return to the optimal fuel consumption range and reducing operating fuel consumption.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0007] In a first aspect, the present invention provides a control system applicable to excavating engines and ISG motors, comprising: an engine, an ISG motor, a hydraulic pump, a sensor module, and a main controller;

[0008] The sensor module is connected to the engine, ISG motor and hydraulic pump respectively, and collects the pressure and displacement of the hydraulic pump, as well as the speed of the ISG motor and the speed of the engine.

[0009] The main controller is connected to the sensor module. Based on the pressure and displacement of the hydraulic pump, it generates a first compensation torque and a second compensation torque, respectively. Based on the engine speed and the ISG motor speed, it generates a third compensation torque and a fourth compensation torque. Based on the engine speed change, it calculates a fifth compensation torque using a PI control algorithm. The maximum value among the first, second, third, and fourth compensation torques is selected and summed with the fifth compensation torque to obtain the target compensation torque for the ISG motor. Based on the target compensation torque of the ISG motor, the ISG motor is controlled to perform torque compensation for the engine.

[0010] Optionally, the main controller calculates the change in engine speed Δn1 based on the engine speed n1, where Δn1 = f(n1);

[0011] When the engine speed change Δn1 is greater than the set threshold, the target compensation torque of the ISG motor is calculated.

[0012] Alternatively, the main controller calculates the hydraulic pump pressure difference Δp based on the actual hydraulic pump pressure p1 collected by the sensor module, where Δp = f(p1).

[0013] When the hydraulic pump pressure difference Δp is greater than the set threshold, the target compensation torque of the ISG motor is calculated.

[0014] Optionally, the sensor module includes: an engine speed sensor, an ISG motor speed sensor, a current sensor, and a pressure sensor;

[0015] The engine speed sensor is connected to both the engine and the main controller.

[0016] The ISG motor speed sensor is connected to both the ISG motor and the main controller.

[0017] The current sensor is connected to the hydraulic pump and the main controller, respectively;

[0018] The pressure sensor is connected to the hydraulic pump and the main controller, respectively.

[0019] Optionally, the main controller includes a load feedforward controller and an engine feedforward controller.

[0020] Optionally, when the excavator's operation is obstructed, the hydraulic pump pressure rises sharply, generating a hydraulic pump pressure difference Δp. If the hydraulic pump pressure difference Δp is greater than a set threshold, a first compensation torque is calculated by the load feedforward controller. The calculation formula for the first compensation torque is:

[0021]

[0022] Where T1 is the first compensation torque, K1 is the pressure compensation coefficient of the load feedforward controller, Δp is the hydraulic pump pressure difference, and V1 is the actual displacement of the hydraulic pump. V1 is calculated by the main controller based on the actual hydraulic pump current I1 collected by the sensor module, and V1 = f(I1).

[0023] Optionally, when the hydraulic pump suddenly accelerates, its displacement increases sharply, generating a hydraulic pump displacement difference ΔV. If the hydraulic pump displacement difference ΔV is greater than a set threshold, a second compensation torque is calculated by the load feedforward controller. The formula for calculating the second compensation torque is as follows:

[0024]

[0025] Where T2 is the first compensation torque, K2 is the displacement compensation coefficient of the load feedforward controller, ΔV is the hydraulic pump displacement difference, and p1 is the actual pressure of the hydraulic pump, which is acquired by the sensor module.

[0026] Optionally, when the excavator's operation is obstructed, the hydraulic pump pressure will rise sharply, creating a hydraulic pump pressure difference Δp. Due to the increased engine pressure, the engine speed will suddenly drop Δn. f1 The third compensation torque is then calculated by the engine feedforward controller, and the formula for calculating the third compensation torque is as follows:

[0027]

[0028] Where T3 is the third compensation torque, K3 is the pressure compensation coefficient of the engine feedforward controller, and P ISG This refers to the power of the ISG motor.

[0029] Optionally, when the hydraulic pump suddenly accelerates, its displacement increases sharply, creating a displacement difference ΔV. Due to the increased engine displacement, the engine speed suddenly decreases by Δn. f2 Then, the fourth compensation torque is calculated by the engine feedforward controller, and the formula for calculating the fourth compensation torque is:

[0030]

[0031] Where T4 is the fourth compensation torque, K4 is the displacement compensation coefficient of the engine feedforward controller, and P ISG This refers to the power of the ISG motor.

[0032] Optionally, obtain the proportional control parameter K created based on the hydraulic pump pressure difference Δp and the hydraulic pump displacement difference ΔV. p MAP value table;

[0033] The main controller finds the corresponding proportional control parameter K based on the detected hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV. p ;

[0034] When the absolute value of the difference Δn2 between the actual engine speed and the target speed is less than the set threshold, integral control K is activated. i When the integral value Exceeding the upper limit Ki UpL Only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL At that time, only positive deviations are accumulated; Here, e(t) is the calculated value of the integral, which is the cumulative integral function with respect to the difference Δn², and t is the integration time; Ki UpL Ki is the upper limit of integration. DownL This is the lower limit of the integral;

[0035] The final calculated fifth compensation torque T5 is obtained.

[0036] Secondly, the present invention provides a control method applicable to excavator engines and ISG motors, comprising:

[0037] The pressure and displacement of the hydraulic pump, as well as the speed of the ISG motor and the speed of the engine, are collected using a sensor module.

[0038] The first and second compensation torques are generated using the pressure and displacement of the hydraulic pump in the main controller, respectively. The third and fourth compensation torques are generated based on the engine speed and the ISG motor speed. The fifth compensation torque is calculated based on the engine speed change and the PI control algorithm. The maximum value among the first, second, third, and fourth compensation torques is selected and summed with the fifth compensation torque to obtain the target compensation torque for the ISG motor. The ISG motor is then controlled to perform torque compensation on the engine based on the target compensation torque of the ISG motor.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] This invention generates a first compensation torque and a second compensation torque based on the hydraulic pump's pressure and displacement, respectively, according to sudden changes in hydraulic pump (i.e., load). It also generates a third compensation torque and a fourth compensation torque based on sudden changes in engine speed, using the engine speed and the ISG motor's speed. Furthermore, based on the engine speed change and a PI control algorithm, a fifth compensation torque is calculated. The maximum value among the first, second, third, and fourth compensation torques is selected and summed with the fifth compensation torque to serve as the target compensation torque for the ISG motor. Controlling the ISG motor to perform torque compensation on the engine based on this target compensation torque not only enables the engine to quickly return to the set speed, reduces engine friction work, and improves fuel efficiency, but also achieves multi-dimensional improvements in the torque and speed control accuracy of the ISG motor, as well as enhancing speed and torque response speed and control precision. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0042] Figure 1 This is a schematic diagram of the control system of an excavator engine and ISG motor according to one embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the control process of a control system applicable to an excavator engine and an ISG motor according to an embodiment of the present invention;

[0044] in:

[0045] 1-Engine, 2-ISG motor, 3-Hydraulic pump, 4-Engine speed sensor, 5-ISG motor speed sensor, 6-Current sensor, 7-Pressure sensor, 8-Main controller, 9-Battery, 10-Load feedforward controller, 11-Engine feedforward controller. Detailed Implementation

[0046] 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 them. 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.

[0047] 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 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. If 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.

[0048] Example 1

[0049] This invention provides a control system suitable for excavating engines and ISG motors, including: an engine 1, an ISG motor 2, a hydraulic pump 3, a sensor module, a main controller 8, and a battery 9 for power supply;

[0050] The sensor module is connected to the engine 1, ISG motor 2 and hydraulic pump 3 respectively, and collects the pressure and displacement of hydraulic pump 3, as well as the rotation speed of ISG motor 2 and engine 1.

[0051] The main controller 8 is connected to the sensor module. Based on the pressure and displacement of the hydraulic pump 3, it generates a first compensation torque and a second compensation torque, respectively. Based on the speed of the engine 1 and the speed of the ISG motor 2, it generates a third compensation torque and a fourth compensation torque. Based on the change in engine speed, it calculates a fifth compensation torque using a PI control algorithm. The maximum value among the first, second, third, and fourth compensation torques is selected and summed with the fifth compensation torque to obtain the target compensation torque for the ISG motor. Based on the target compensation torque of the ISG motor, the ISG motor 2 is controlled to perform torque compensation on the engine 1.

[0052] In one specific embodiment of the present invention, the main controller 8 calculates the change in engine speed Δn1 based on the engine speed n1, where Δn1 = f(n1);

[0053] When the engine speed change Δn1 is greater than the set threshold, the target compensation torque of the ISG motor is calculated.

[0054] In another specific embodiment of the present invention, the main controller 8 calculates the hydraulic pump pressure difference Δp based on the actual hydraulic pump pressure p1 collected by the sensor module, where Δp = f(p1).

[0055] When the hydraulic pump pressure difference Δp is greater than the set threshold, the target compensation torque of the ISG motor is calculated.

[0056] In one specific embodiment of the present invention, the sensor module includes: an engine speed sensor 4, an ISG motor speed sensor 5, a current sensor 6, and a pressure sensor 7.

[0057] The engine speed sensor 4 is connected to the engine 1 and the main controller 8 respectively, and is used to collect the real-time speed of the engine 1.

[0058] The ISG motor speed sensor 5 is connected to the ISG motor 2 and the main controller 8 respectively, and is used to collect the real-time speed of the ISG motor.

[0059] The current sensor 6 is connected to the hydraulic pump 3 and the main controller 8 respectively, and is used to collect the real-time current value of the hydraulic pump 3.

[0060] The pressure sensor 7 is connected to the hydraulic pump 3 and the main controller 8 respectively, and is used to collect the real-time pressure value of the hydraulic pump 3.

[0061] The main controller 8 includes a load feedforward controller 10 and an engine feedforward controller 11.

[0062] When the excavator's operation is obstructed, the pressure of hydraulic pump 3 rises sharply, generating a hydraulic pump pressure difference Δp. If the hydraulic pump pressure difference Δp is greater than a set threshold, the first compensation torque is calculated by the load feedforward controller 10. The calculation formula for the first compensation torque is:

[0063]

[0064] Where T1 is the first compensation torque, K1 is the pressure compensation coefficient of the load feedforward controller 10, Δp is the hydraulic pump pressure difference, and V1 is the actual displacement of the hydraulic pump. The actual displacement V1 of the hydraulic pump is calculated by the main controller 8 based on the actual hydraulic pump current I1 collected by the sensor module, and V1 = f(I1).

[0065] When hydraulic pump 3 suddenly accelerates, its displacement increases sharply, generating a displacement difference ΔV. If the displacement difference ΔV is greater than a set threshold, the load feedforward controller 10 calculates the second compensation torque. The formula for calculating the second compensation torque is as follows:

[0066]

[0067] Where T2 is the first compensation torque, K2 is the displacement compensation coefficient of the load feedforward controller 10, ΔV is the hydraulic pump displacement difference, and p1 is the actual pressure of the hydraulic pump, which is acquired by the sensor module.

[0068] When the excavator's operation is obstructed, the pressure of hydraulic pump 3 will rise sharply, creating a hydraulic pump pressure difference Δp. Due to the increased engine pressure, the engine speed will suddenly drop Δn.f1 Then, the third compensation torque is calculated by the engine feedforward controller 11, and the calculation formula for the third compensation torque is:

[0069]

[0070] Where T3 is the third compensation torque, K3 is the pressure compensation coefficient of the engine feedforward controller 11, and P ISG This refers to the power of ISG motor 2.

[0071] When hydraulic pump 3 suddenly accelerates, its displacement increases sharply, creating a displacement difference ΔV. Simultaneously, due to the increased displacement of engine 1, its speed suddenly decreases by Δn. f2 Then, the fourth compensation torque is calculated by the engine feedforward controller 11, and the calculation formula for the fourth compensation torque is:

[0072]

[0073] Where T4 is the fourth compensation torque, K4 is the displacement compensation coefficient of the engine feedforward controller 11, and P ISG This refers to the power of ISG motor 2.

[0074] Based on the hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV, create the proportional control parameter K. p MAP value table;

[0075] Based on the detected hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV, the main controller 8 finds the corresponding proportional control parameter K. p ;

[0076] When the absolute value of the difference Δn2 between the actual engine speed and the target speed is less than the set threshold, integral control K is activated. i When the integral value Exceeding the upper limit Ki UpL Only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL At that time, only positive deviations are accumulated; Here, e(t) is the calculated value of the integral, which is the cumulative integral function with respect to the difference Δn², and t is the integration time; Ki UpL Ki is the upper limit of integration. DownL This is the lower limit of the integral;

[0077] The final calculated fifth compensation torque T5 is obtained.

[0078] The following is combined with Figure 2 The present invention provides a detailed description of the operation of a control system applicable to excavator engines and ISG motors in an embodiment of the present invention.

[0079] Considering that the external load is random and variable during excavator operation, the engine 1 often slows down or speeds up, and the time to return to normal is too long. Therefore, it is necessary to calculate the required torque and speed, and control the ISG motor 2 to compensate the torque of the engine 1, so that the engine speed can be quickly restored to the optimal fuel consumption range and reduce the fuel consumption during operation.

[0080] Therefore, this invention proposes a control system suitable for excavator engines and ISG motors. In actual use, this control system executes the following process:

[0081] S1: Collect data, calculate engine speed, and determine whether to activate torque compensation command.

[0082] The vehicle controller collects the engine speed n1 and calculates the engine speed change Δn1 = f(n1) by the control program. In the specific implementation process, the engine speed change can be obtained by subtracting the speed value of the next moment from the speed value of the previous moment.

[0083] The system checks whether the absolute value of the engine speed change Δn1 is greater than a set threshold. If the engine speed change Δn1 is greater than the set threshold, a torque compensation command is initiated. To avoid frequent command initiation, based on experimental data analysis, the reference speed threshold is set at 30 r / min.

[0084] The main controller 8 collects the output signals of the pressure sensor 7 and the current sensor 6 connected to the hydraulic pump 3, and converts the output signals into the actual pressure p1 and the actual current I1 of the hydraulic pump. Based on the conversion formula of the current and displacement of the hydraulic pump 3 (obtained by test), the actual displacement V1 of the hydraulic pump is calculated, V1 = f(I1), and the pressure difference Δp of the hydraulic pump is calculated, Δp = f(p1).

[0085] Determine if the absolute value of the hydraulic pump pressure difference Δp is greater than a set threshold. If Δp is greater than the set threshold, then initiate the torque compensation command.

[0086] The main controller 8 collects the ISG motor speed n ISG ISG motor power P ISG .

[0087] S2: Power compensation for ISG motor 2 based on load pressure and displacement.

[0088] When the excavator's operation is obstructed, the pressure of hydraulic pump 3 will rise sharply, generating a hydraulic pump pressure difference Δp (i.e., pressure increase Δp). If the calculated hydraulic pump pressure difference Δp is greater than the set value of 2MPa, then the first compensation torque is calculated by the load feedforward controller 10. The formula for calculating the first compensation torque is:

[0089]

[0090] Where T1 is the first compensation torque (i.e. Figure 2 In the compensation torque T1), K1 is the pressure compensation coefficient of the load feedforward controller 10, Δp is the hydraulic pump pressure difference, V1 is the actual displacement of the hydraulic pump, and the actual displacement V1 of the hydraulic pump is calculated by the main controller 8 based on the actual hydraulic pump current I1 collected by the sensor module, V1=f(I1).

[0091] When the hydraulic system suddenly accelerates, a hydraulic pump displacement difference ΔV is generated (i.e., the hydraulic pump displacement increases by ΔV). If the calculated hydraulic pump displacement difference ΔV is greater than the set value of 10cc / rev, the load feedforward controller 10 calculates the second compensation torque. The formula for calculating the second compensation torque is as follows:

[0092]

[0093] Where T2 is the second compensation torque (i.e. Figure 2 The compensation torque T2 is given by K2, which is the displacement compensation coefficient of the load feedforward controller 10. ΔV is the displacement difference of the hydraulic pump, and p1 is the actual pressure of the hydraulic pump, which is obtained by the sensor module.

[0094] S3: Torque compensation for ISG motor 2 based on engine speed.

[0095] When the excavator's operation is obstructed, the pressure of hydraulic pump 3 will rise sharply, creating a hydraulic pump pressure difference Δp (i.e., pressure increase Δp). Due to the increased pressure, the engine speed of engine 1 will suddenly decrease by Δn. f1 To bring the engine speed back to the set value, the engine feedforward controller 11 calculates the third compensation torque, and the formula for calculating the third compensation torque is as follows:

[0096]

[0097] Where T3 is the third compensation torque (i.e. Figure 2 The compensation torque T3), K3 is the pressure compensation coefficient of the engine feedforward controller 11, P ISG This refers to the power of ISG motor 2.

[0098] When the hydraulic system suddenly accelerates, the hydraulic pump displacement increases sharply, creating a hydraulic pump displacement difference ΔV (i.e., the hydraulic pump displacement increases by ΔV). As a result, engine speed 1 suddenly decreases by Δn due to the increased displacement. f2 To bring the engine speed back to the set value, the engine feedforward controller 11 calculates the fourth compensation torque, and the formula for calculating the fourth compensation torque is as follows:

[0099]

[0100] Where T4 is the fourth compensation torque (i.e. Figure 2 The compensation torque T4), K4 is the displacement compensation coefficient of the engine feedforward controller 11, P ISG This refers to the power of ISG motor 2.

[0101] S4: Perform closed-loop speed control on ISG motor 2 based on the load.

[0102] When the excavator's operation is obstructed, the hydraulic system pressure rises sharply, increasing the power demand at the load end. To maintain a constant engine speed, the output torque of engine 1 needs to be increased. Due to the increased load, the speed of engine 1 suddenly drops. The ISG motor 2, controlled by a PI controller, increases its output power to compensate for the insufficient power of engine 1 and quickly drives engine 1 back to the set value. Because the engine speed fluctuates frequently, a single PI control parameter cannot meet the control requirements. Therefore, a proportional control parameter K is created based on the hydraulic pump pressure difference Δp, the hydraulic pump displacement difference ΔV, and experimental experience. p The MAP value table; the main controller 8 finds the corresponding proportional control parameter K based on the detected hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV. p To avoid integral saturation and deterioration of control performance, integral control K is initiated when the absolute value of the difference between the actual speed and the target speed, Δn2, is less than 5 rev / min. i In addition, when the integral value Exceeding the upper limit Ki UpL Only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL At that time, only positive deviations are accumulated; Here, e(t) is the calculated value of the integral, e(t) is the cumulative integral function with respect to the difference Δn1, and t is the integration time; Ki UpL The maximum score is [value], and the experience value is [value], which are not given here. Ki DownL The lower limit of integration is an empirical value and is not given here. The final calculated output is the fifth compensation torque T5 (i.e., Figure 2 The compensation torque T5 in the middle,

[0103] The maximum value among the first, second, third, and fourth compensation torques is selected and summed with the fifth compensation torque to obtain the target compensation torque for the ISG motor. Based on the target compensation torque of the ISG motor, the ISG motor 2 is controlled to perform torque compensation on the engine 1, so that the engine speed can be quickly restored to the optimal fuel consumption range, thereby reducing operating fuel consumption.

[0104] Example 2

[0105] This invention provides a control method applicable to excavator engines and ISG motors, comprising the following steps:

[0106] (1) The pressure and displacement of the hydraulic pump 3, the speed of the ISG motor 2 and the speed of the engine 1 are collected by the sensor module respectively.

[0107] (2) Using the pressure and displacement of the hydraulic pump 3 of the main controller 8, the first compensation torque and the second compensation torque are generated respectively; based on the speed of the engine 1 and the speed of the ISG motor 2, the third compensation torque and the fourth compensation torque are generated; based on the change in engine speed and the PI control algorithm, the fifth compensation torque is calculated; the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque are selected, and the sum of the first compensation torque, the second compensation torque and the fourth compensation torque is used as the target compensation torque of the ISG motor; based on the target compensation torque of the ISG motor, the ISG motor 2 is controlled to perform torque compensation on the engine 1.

[0108] In one specific embodiment of the present invention, the main controller 8 calculates the change in engine speed Δn1 based on the engine speed n1, where Δn1 = f(n1);

[0109] When the engine speed change Δn1 is greater than the set threshold, the target compensation torque of the ISG motor is calculated.

[0110] In another specific embodiment of the present invention, the main controller 8 calculates the hydraulic pump pressure difference Δp based on the actual hydraulic pump pressure p1 collected by the sensor module, where Δp = f(p1).

[0111] When the hydraulic pump pressure difference Δp is greater than the set threshold, the target compensation torque of the ISG motor is calculated.

[0112] In one specific embodiment of the present invention, the sensor module includes: an engine speed sensor 4, an ISG motor speed sensor 5, a current sensor 6, and a pressure sensor 7.

[0113] The engine speed sensor 4 is connected to the engine 1 and the main controller 8 respectively, and is used to collect the real-time speed of the engine 1.

[0114] The ISG motor speed sensor 5 is connected to the ISG motor 2 and the main controller 8 respectively, and is used to collect the real-time speed of the ISG motor.

[0115] The current sensor 6 is connected to the hydraulic pump 3 and the main controller 8 respectively, and is used to collect the real-time current value of the hydraulic pump 3.

[0116] The pressure sensor 7 is connected to the hydraulic pump 3 and the main controller 8 respectively, and is used to collect the real-time pressure value of the hydraulic pump 3.

[0117] The main controller 8 includes a load feedforward controller 10 and an engine feedforward controller 11.

[0118] When the excavator's operation is obstructed, the pressure of hydraulic pump 3 rises sharply, generating a hydraulic pump pressure difference Δp. If the hydraulic pump pressure difference Δp is greater than a set threshold, the first compensation torque is calculated by the load feedforward controller 10. The calculation formula for the first compensation torque is:

[0119]

[0120] Where T1 is the first compensation torque, K1 is the pressure compensation coefficient of the load feedforward controller 10, Δp is the hydraulic pump pressure difference, and V1 is the actual displacement of the hydraulic pump. The actual displacement V1 of the hydraulic pump is calculated by the main controller 8 based on the actual hydraulic pump current I1 collected by the sensor module, and V1 = f(I1).

[0121] When hydraulic pump 3 suddenly accelerates, its displacement increases sharply, generating a displacement difference ΔV. If the displacement difference ΔV is greater than a set threshold, the load feedforward controller 10 calculates the second compensation torque. The formula for calculating the second compensation torque is as follows:

[0122]

[0123] Where T2 is the first compensation torque, K2 is the displacement compensation coefficient of the load feedforward controller 10, ΔV is the hydraulic pump displacement difference, and p1 is the actual pressure of the hydraulic pump, which is acquired by the sensor module.

[0124] When the excavator's operation is obstructed, the pressure of hydraulic pump 3 will rise sharply, creating a hydraulic pump pressure difference Δp. Due to the increased engine pressure, the engine speed will suddenly drop Δn. f1 Then, the third compensation torque is calculated by the engine feedforward controller 11, and the calculation formula for the third compensation torque is:

[0125]

[0126] Where T3 is the third compensation torque, K3 is the pressure compensation coefficient of the engine feedforward controller 11, and P ISG This refers to the power of ISG motor 2.

[0127] When hydraulic pump 3 suddenly accelerates, its displacement increases sharply, creating a displacement difference ΔV. Simultaneously, due to the increased displacement of engine 1, its speed suddenly decreases by Δn. f2 Then, the fourth compensation torque is calculated by the engine feedforward controller 11, and the calculation formula for the fourth compensation torque is:

[0128]

[0129] Where T4 is the fourth compensation torque, K4 is the displacement compensation coefficient of the engine feedforward controller 11, and P ISG This refers to the power of ISG motor 2.

[0130] Based on the hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV, create the proportional control parameter K. p MAP value table;

[0131] Based on the detected hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV, the main controller 8 finds the corresponding proportional control parameter K. p ;

[0132] When the absolute value of the difference Δn2 between the actual engine speed and the target speed is less than the set threshold, integral control K is activated. i When the integral value Exceeding the upper limit Ki UpL Only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL At that time, only positive deviations are accumulated; Here, e(t) is the calculated value of the integral, which is the cumulative integral function with respect to the difference Δn², and t is the integration time; Ki UpL Ki is the upper limit of integration. DownL This is the lower limit of the integral;

[0133] The final calculated fifth compensation torque T5 is obtained.

[0134] The following is combined with Figure 2 The present invention provides a detailed description of the operation process of the control method applicable to excavator engines and ISG motors in a specific embodiment.

[0135] Considering that the external load is random and variable during excavator operation, the engine 1 often slows down or speeds up, and the time to return to normal is too long. Therefore, it is necessary to calculate the required torque and speed, and control the ISG motor 2 to compensate the torque of the engine 1, so that the engine speed can be quickly restored to the optimal fuel consumption range and reduce the fuel consumption during operation.

[0136] Therefore, this invention proposes a control method applicable to excavator engines and ISG motors. In actual use, this control method executes the following process:

[0137] S1: Collect data, calculate engine speed, and determine whether to activate torque compensation command.

[0138] The vehicle controller collects the engine speed n1 and calculates the engine speed change Δn1 = f(n1) by the control program. In the specific implementation process, the engine speed change can be obtained by subtracting the speed value of the next moment from the speed value of the previous moment.

[0139] The system checks whether the absolute value of the engine speed change Δn1 is greater than a set threshold. If the engine speed change Δn1 is greater than the set threshold, a torque compensation command is initiated. To avoid frequent command initiation, based on experimental data analysis, the reference speed threshold is set at 30 r / min.

[0140] The main controller 8 collects the output signals of the pressure sensor 7 and the current sensor 6 connected to the hydraulic pump 3, and converts the output signals into the actual pressure p1 and the actual current I1 of the hydraulic pump. Based on the conversion formula of the current and displacement of the hydraulic pump 3 (obtained by test), the actual displacement V1 of the hydraulic pump is calculated, V1 = f(I1), and the pressure difference Δp of the hydraulic pump is calculated, Δp = f(p1).

[0141] Determine if the absolute value of the hydraulic pump pressure difference Δp is greater than a set threshold. If Δp is greater than the set threshold, then initiate the torque compensation command.

[0142] The main controller 8 collects the ISG motor speed n ISG ISG motor power P ISG .

[0143] S2: Power compensation for ISG motor 2 based on load pressure and displacement.

[0144] When the excavator's operation is obstructed, the pressure of hydraulic pump 3 will rise sharply, generating a hydraulic pump pressure difference Δp (i.e., pressure increase Δp). If the calculated hydraulic pump pressure difference Δp is greater than the set value of 2MPa, then the first compensation torque is calculated by the load feedforward controller 10. The formula for calculating the first compensation torque is:

[0145]

[0146] Where T1 is the first compensation torque (i.e. Figure 2 In the compensation torque T1), K1 is the pressure compensation coefficient of the load feedforward controller 10, Δp is the hydraulic pump pressure difference, V1 is the actual displacement of the hydraulic pump, and the actual displacement V1 of the hydraulic pump is calculated by the main controller 8 based on the actual hydraulic pump current I1 collected by the sensor module, V1=f(I1).

[0147] When the hydraulic system suddenly accelerates, a hydraulic pump displacement difference ΔV is generated (i.e., the hydraulic pump displacement increases by ΔV). If the calculated hydraulic pump displacement difference ΔV is greater than the set value of 10cc / rev, the load feedforward controller 10 calculates the second compensation torque. The formula for calculating the second compensation torque is as follows:

[0148]

[0149] Where T2 is the second compensation torque (i.e. Figure 2The compensation torque T2 is given by K2, which is the displacement compensation coefficient of the load feedforward controller 10. ΔV is the displacement difference of the hydraulic pump, and p1 is the actual pressure of the hydraulic pump, which is obtained by the sensor module.

[0150] S3: Torque compensation for ISG motor 2 based on engine speed.

[0151] When the excavator's operation is obstructed, the pressure of hydraulic pump 3 will rise sharply, creating a hydraulic pump pressure difference Δp (i.e., pressure increase Δp). Due to the increased pressure, the engine speed of engine 1 will suddenly decrease by Δn. f1 To bring the engine speed back to the set value, the engine feedforward controller 11 calculates the third compensation torque, and the formula for calculating the third compensation torque is as follows:

[0152]

[0153] Where T3 is the third compensation torque (i.e. Figure 2 The compensation torque T3), K3 is the pressure compensation coefficient of the engine feedforward controller 11, P ISG This refers to the power of ISG motor 2.

[0154] When the hydraulic system suddenly accelerates, the hydraulic pump displacement increases sharply, creating a hydraulic pump displacement difference ΔV (i.e., the hydraulic pump displacement increases by ΔV). As a result, engine speed 1 suddenly decreases by Δn due to the increased displacement. f2 To bring the engine speed back to the set value, the engine feedforward controller 11 calculates the fourth compensation torque, and the formula for calculating the fourth compensation torque is as follows:

[0155]

[0156] Where T4 is the fourth compensation torque (i.e. Figure 2 The compensation torque T4), K4 is the displacement compensation coefficient of the engine feedforward controller 11, P ISG This refers to the power of ISG motor 2.

[0157] S4: Perform closed-loop speed control on ISG motor 2 based on the load.

[0158] When the excavator's operation is obstructed, the hydraulic system pressure rises sharply, increasing the power demand at the load end. To maintain a constant engine speed, the output torque of engine 1 needs to be increased. Due to the increased load, the speed of engine 1 suddenly drops. The ISG motor 2, controlled by a PI controller, increases its output power to compensate for the insufficient power of engine 1 and quickly drives engine 1 back to the set value. Because the engine speed fluctuates frequently, a single PI control parameter cannot meet the control requirements. Therefore, a proportional control parameter K is created based on the hydraulic pump pressure difference Δp, the hydraulic pump displacement difference ΔV, and experimental experience. pThe MAP value table; the main controller 8 finds the corresponding proportional control parameter K based on the detected hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV. p To avoid integral saturation and deterioration of control performance, integral control K is initiated when the absolute value of the difference between the actual speed and the target speed, Δn2, is less than 5 rev / min. i In addition, when the integral value Exceeding the upper limit Ki UpL Only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL At that time, only positive deviations are accumulated; Here, e(t) is the calculated value of the integral, e(t) is the cumulative integral function with respect to the difference Δn1, and t is the integration time; Ki UpL The maximum score is [value], and the experience value is [value], which are not given here. Ki DownL This is the lower limit of integration, an empirical value, and is not given here. The final calculated output is the fifth compensation torque (i.e....). Figure 2 The compensation torque T5 in the middle,

[0159] The maximum value among the first, second, third, and fourth compensation torques is selected and summed with the fifth compensation torque to obtain the target compensation torque for the ISG motor. Based on the target compensation torque of the ISG motor, the ISG motor 2 is controlled to perform torque compensation on the engine 1, so that the engine speed can be quickly restored to the optimal fuel consumption range, thereby reducing operating fuel consumption.

[0160] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0161] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1A device that provides the functions specified in one or more boxes.

[0162] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0163] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0164] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

[0165] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A control system suitable for excavator engines and ISG motors, characterized in that, include: Engine, ISG motor, hydraulic pump, sensor module, and main controller; The sensor module is connected to the engine, ISG motor and hydraulic pump respectively, and collects the pressure and displacement of the hydraulic pump, as well as the speed of the ISG motor and the speed of the engine. The main controller is connected to the sensor module. Based on the pressure and displacement of the hydraulic pump, it generates a first compensation torque and a second compensation torque, respectively. Based on the engine speed and the ISG motor speed, it generates a third compensation torque and a fourth compensation torque. Based on the change in engine speed, it calculates a fifth compensation torque using a PI control algorithm. The maximum value among the first, second, third, and fourth compensation torques is selected and summed with the fifth compensation torque to obtain the target compensation torque for the ISG motor. Based on the target compensation torque of the ISG motor, the ISG motor is controlled to perform torque compensation for the engine. The main controller calculates the change in engine speed Δn1 based on the engine speed n1, where Δn1 = f(n1); When the engine speed change Δn1 is greater than the set threshold, the target compensation torque of the ISG motor is calculated. Alternatively, the main controller calculates the hydraulic pump pressure difference Δp based on the actual hydraulic pump pressure p1 collected by the sensor module, where Δp = f(p1). When the hydraulic pump pressure difference Δp is greater than the set threshold, the target compensation torque of the ISG motor is calculated. When the excavator's operation is obstructed, the hydraulic pump pressure rises sharply, generating a hydraulic pump pressure difference Δp. If the hydraulic pump pressure difference Δp is greater than a set threshold, the load feedforward controller calculates the first compensation torque. The formula for calculating the first compensation torque is: Where T1 is the first compensation torque, K1 is the pressure compensation coefficient of the load feedforward controller, and Δp is the hydraulic pump pressure difference; V1 is the actual displacement of the hydraulic pump. V1 is calculated by the main controller based on the actual hydraulic pump current I1 collected by the sensor module. V1 = f(I1).

2. The control system for excavating engines and ISG motors according to claim 1, characterized in that: The sensor module includes: an engine speed sensor, an ISG motor speed sensor, a current sensor, and a pressure sensor; The engine speed sensor is connected to both the engine and the main controller. The ISG motor speed sensor is connected to both the ISG motor and the main controller. The current sensor is connected to the hydraulic pump and the main controller, respectively; The pressure sensor is connected to the hydraulic pump and the main controller, respectively.

3. A control system for excavating engines and ISG motors according to claim 2, characterized in that: The main controller includes a load feedforward controller and an engine feedforward controller.

4. A control system for excavating engines and ISG motors according to claim 3, characterized in that: When the hydraulic pump suddenly accelerates, its displacement increases sharply, generating a displacement difference ΔV. If this displacement difference ΔV exceeds a set threshold, a second compensation torque is calculated by the load feedforward controller. The formula for calculating the second compensation torque is as follows: Where T2 is the first compensation torque, K2 is the displacement compensation coefficient of the load feedforward controller, and ΔV is the displacement difference of the hydraulic pump. p1 represents the actual pressure of the hydraulic pump, which is acquired by the sensor module.

5. A control system for excavating engines and ISG motors according to claim 3, characterized in that: When the excavator's operation is obstructed, the hydraulic pump pressure will rise sharply, creating a hydraulic pump pressure difference Δp. Due to the increased engine pressure, the engine speed will suddenly drop Δn. f1 The third compensation torque is then calculated by the engine feedforward controller, and the formula for calculating the third compensation torque is as follows: Where T3 is the third compensation torque, K3 is the pressure compensation coefficient of the engine feedforward controller, and P ISG This refers to the power of the ISG motor.

6. A control system for excavating engines and ISG motors according to claim 3, characterized in that: When the hydraulic pump suddenly accelerates, its displacement increases sharply, creating a displacement difference ΔV. Simultaneously, due to the increased engine displacement, the engine speed suddenly decreases by Δn. f2 Then, the fourth compensation torque is calculated by the engine feedforward controller, and the formula for calculating the fourth compensation torque is: Where T4 is the fourth compensation torque, K4 is the displacement compensation coefficient of the engine feedforward controller, and P ISG This refers to the power of the ISG motor.

7. A control system for excavating engines and ISG motors according to claim 3, characterized in that: Obtain the proportional control parameter K created based on the hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV. p MAP value table; The main controller finds the corresponding proportional control parameter K based on the detected hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV. p ; When the absolute value of the difference Δn2 between the actual engine speed and the target speed is less than the set threshold, integral control K is activated. i When the integral value Exceeding the upper limit Ki UpL Only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL At that time, only positive deviations are accumulated; Here, e(t) is the calculated value of the integral, which is the cumulative integral function with respect to the difference Δn², and t is the integration time; Ki UpL Ki is the upper limit of integration. DownL This is the lower limit of the integral; The final calculated fifth compensation torque T5 is obtained.

8. A control method applicable to excavator engines and ISG motors, characterized in that, include: The pressure and displacement of the hydraulic pump, as well as the speed of the ISG motor and the speed of the engine, are collected using a sensor module. The first and second compensation torques are generated using the pressure and displacement of the hydraulic pump in the main controller, respectively; the third and fourth compensation torques are generated based on the engine speed and the ISG motor speed; the fifth compensation torque is calculated based on the engine speed change and the PI control algorithm; the maximum value among the first, second, third, and fourth compensation torques is selected and summed with the fifth compensation torque to obtain the target compensation torque for the ISG motor; the ISG motor is then controlled to perform torque compensation on the engine based on the target compensation torque of the ISG motor. The main controller calculates the change in engine speed Δn1 based on the engine speed n1, where Δn1 = f(n1); When the engine speed change Δn1 is greater than the set threshold, the target compensation torque of the ISG motor is calculated. Alternatively, the main controller calculates the hydraulic pump pressure difference Δp based on the actual hydraulic pump pressure p1 collected by the sensor module, where Δp = f(p1). When the hydraulic pump pressure difference Δp is greater than the set threshold, the target compensation torque of the ISG motor is calculated. When the excavator's operation is obstructed, the hydraulic pump pressure rises sharply, generating a hydraulic pump pressure difference Δp. If the hydraulic pump pressure difference Δp is greater than a set threshold, the load feedforward controller calculates the first compensation torque. The formula for calculating the first compensation torque is: Where T1 is the first compensation torque, K1 is the pressure compensation coefficient of the load feedforward controller, and Δp is the hydraulic pump pressure difference; V1 is the actual displacement of the hydraulic pump. V1 is calculated by the main controller based on the actual hydraulic pump current I1 collected by the sensor module. V1 = f(I1).

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