Control system and control method suitable for excavator engine and ISG electric motor

Abstract

Disclosed in the present invention are a control system and control method suitable for an excavator engine and an ISG electric motor. The control system comprises an engine, an ISG electric motor, a hydraulic pump, a sensor module and a master controller, wherein the sensor module collects the pressure and displacement of the hydraulic pump, the rotation speed of the ISG electric motor and the rotation speed of the engine; and the master controller respectively generates a first compensation torque and a second compensation torque on the basis of the pressure and displacement of the hydraulic pump, generates a third compensation torque and a fourth compensation torque on the basis of the rotation speed of the engine and the rotation speed of the ISG electric motor, performs calculation on the basis of a rotation speed variation of the engine and in view of a PI control algorithm, so as to obtain a fifth compensation torque, selects the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque, calculates the sum of the maximum value and the fifth compensation torque as a target compensation torque of the ISG electric motor, and controls the ISG electric motor to perform torque compensation on the engine. In the present invention, the ISG electric motor is controlled to perform torque compensation on the engine, so that the rotation speed of the engine is quickly restored to an optimal fuel consumption zone, thereby reducing fuel consumption during operation.

Description

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

[0001] The present invention belongs to the field of new energy engineering machinery, and specifically relates to a control system and a control method suitable for an excavator engine and an ISG motor. Background Art

[0002] Excavators are multi-purpose construction machines, often used for digging, grading, loading, and crushing operations. They operate under highly cyclical conditions and complex, variable external loads. This fluctuating load causes the engine speed to fluctuate constantly, further causing the engine to frequently fluctuate between high-efficiency and low-efficiency zones. Under these transient operating conditions, fuel consumption increases significantly. Increased fuel consumption increases customer costs.

[0003] To achieve energy conservation, hybrid excavators incorporate an ISG motor. The excavator is driven by a coaxially connected engine and ISG motor. The ISG motor can operate in two modes: drive and power generation. In drive mode, it assists the engine to improve load response. In power generation mode, excess engine power is used to charge the battery, which then drives excavator accessories such as the electronic water pump, fan, and electric slewing mechanism. Because they are coaxially connected in parallel, the engine and motor maintain the same speed, allowing the ISG motor to assist in the drive. Compared to engine-only operation, the ISG motor offers better speed regulation. Furthermore, the motor's high control precision and fast response mitigate the effects of sudden load changes on the engine.

[0004] Currently, constant engine speed control is typically achieved by controlling the engine throttle using a PLC, stepper motor, and rack and pinion based on engine speed differences. However, this approach suffers from long response times and a lack of ability to mitigate load disturbances. For powertrains with variable loads, this results in the engine spending relatively long periods of time in its inefficient zone.

[0005] Summary of the Invention

[0006] In response to the above problems, the present invention proposes a control system and control method suitable for an excavator engine and an ISG motor, which controls the ISG motor to compensate for the engine torque, so that the engine speed can quickly return to the optimal fuel consumption zone, thereby reducing operating fuel consumption.

[0007] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0008] In a first aspect, the present invention provides a control system for an excavator engine and an ISG motor, the control system comprising: an engine, an ISG motor, a hydraulic pump, a sensor module, and a main controller;

[0009] The sensor modules are connected to the engine, ISG motor and hydraulic pump respectively, and the sensor modules are configured to: collect the pressure and displacement of the hydraulic pump, the speed of the ISG motor and the speed of the engine;

[0010] The main controller is connected to the sensor module, and the main controller is configured to: generate a first compensation torque and a second compensation torque based on the pressure and displacement of the hydraulic pump, respectively; generate a third compensation torque and a fourth compensation torque based on the engine speed and the speed of the ISG motor; calculate the fifth compensation torque based on the engine speed change and the PI control algorithm; filter out the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque, sum the filtered maximum value with the fifth compensation torque as the target compensation torque of the ISG motor, and control the ISG motor to perform torque compensation on the engine based on the target compensation torque of the ISG motor.

[0011] Optionally, the main controller is configured to: calculate the engine speed change Δn1 based on the engine speed n1, applying Δn1=f(n1); and calculate the ISG motor target compensation torque when the engine speed change Δn1 is greater than a set threshold.

[0012] Alternatively, the main controller is configured to: calculate the hydraulic pump pressure difference Δp based on the actual hydraulic pump pressure p1 collected by the sensor module, applying Δp=f(p1); and when the hydraulic pump pressure difference Δp is greater than a set threshold, calculate the ISG motor target compensation torque.

[0013] Optionally, the sensor module includes: an engine speed sensor, an ISG motor speed sensor, a current sensor and a pressure sensor;

[0014] The engine speed sensor is connected to the engine and the main controller respectively;

[0015] The ISG motor speed sensor is connected to the ISG motor and the main controller respectively;

[0016] The current sensor is connected to the hydraulic pump and the main controller respectively;

[0017] The pressure sensors are connected to the hydraulic pump and the main controller respectively.

[0018] Optionally, the main controller includes a load feedforward controller and an engine feedforward controller.

[0019] Optionally, the load feedforward controller is configured such that: when the excavator operation is obstructed and the pressure of the hydraulic pump rises sharply to generate a hydraulic pump pressure difference Δp, if the hydraulic pump pressure difference Δp is greater than a set threshold, the load feedforward controller calculates a first compensation torque, and the calculation formula of the first compensation torque is:

[0020] Wherein, T1 is the first compensation torque, K1 is the pressure compensation coefficient of the load feedforward controller, Δp is the hydraulic pump pressure difference; V1 is the actual displacement of the hydraulic pump, wherein V1 is calculated by the main controller based on the actual hydraulic pump current I1 collected by the sensor module, and V1 = f(I1) applies.

[0021] Optionally, the load feedforward controller is configured such that: when the hydraulic pump suddenly accelerates and the displacement of the hydraulic pump increases sharply, thereby generating a hydraulic pump displacement difference ΔV, if the hydraulic pump displacement difference ΔV is greater than a set threshold, the load feedforward controller calculates a second compensation torque, and the calculation formula of the second compensation torque is:

[0022] Among them, T2 is the first compensation torque, K2 is the displacement compensation coefficient of the load feedforward controller, ΔV is the hydraulic pump displacement difference; p1 is the actual pressure of the hydraulic pump, which is collected by the sensor module.

[0023] Optionally, the engine feedforward controller is configured such that: when the excavator operation is blocked and the pressure of the hydraulic pump rises sharply to generate a hydraulic pump pressure difference Δp, the engine speed suddenly drops Δn due to the increase in engine pressure. f1 , the third compensation torque is calculated by the engine feedforward controller, and the calculation formula of the third compensation torque is:

[0024] Among them, T3 is the third compensation torque, K3 is the pressure compensation coefficient of the engine feedforward controller, P ISG is the power of the ISG motor.

[0025] Optionally, the engine feedforward controller is configured such that: when the hydraulic pump suddenly accelerates and the hydraulic pump displacement increases sharply to generate a hydraulic pump displacement difference ΔV, the engine speed suddenly drops Δn due to the increase in engine displacement. f2 , the fourth compensation torque is calculated by the engine feedforward controller, and the calculation formula of the fourth compensation torque is:

[0026] Among them, T4 is the fourth compensation torque, K4 is the displacement compensation coefficient of the engine feedforward controller, P ISG is the power of the ISG motor.

[0027] Optionally, the main controller is configured to: obtain a proportional control parameter K created according to the hydraulic pump pressure difference Δp and the hydraulic pump displacement difference ΔV p MAP value table; according to the detected hydraulic pump pressure difference Δp, hydraulic pump displacement difference ΔV, find the corresponding proportional control parameter K p ;

[0028] The main controller is configured to start the integral control k when the absolute value of the difference Δn2 between the actual engine speed and the target speed is less than a set threshold. i , when the integral value Exceeding Ki limit UpL , only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL When , only positive deviations are accumulated; is the integral calculation value, e(t) is the cumulative integral function about the difference Δn2, and t is the integration time; Ki UpL is the upper limit of the integral, Ki DownL is the lower limit of the integral;

[0029] Finally, the fifth compensation torque T5 is calculated.

[0030] In a second aspect, the present invention provides a control method applicable to an excavator engine and an ISG motor, the control method comprising:

[0031] The sensor module is used to collect the pressure and displacement of the hydraulic pump, the speed of the ISG motor and the speed of the engine;

[0032] Using a main controller, a first compensation torque and a second compensation torque are generated based on the pressure and displacement of the hydraulic pump respectively; a third compensation torque and a fourth compensation torque are generated based on the speed of the engine and the speed of the ISG motor respectively; a fifth compensation torque is calculated based on the change in engine speed and based on a PI control algorithm; the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque is screened out, the screened maximum value and the fifth compensation torque are summed as the target compensation torque of the ISG motor, and the ISG motor is controlled to perform torque compensation on the engine based on the target compensation torque of the ISG motor.

[0033] In some advantageous embodiments, a control method applicable to an excavator engine and an ISG motor according to the present invention may be implemented by a control system applicable to an excavator engine and an ISG motor according to the present invention.

[0034] In the third aspect, the present invention provides a control method suitable for an excavator engine and an ISG motor, the control method comprising: obtaining the pressure and displacement of a hydraulic pump, and the speed of the ISG motor and the speed of the engine; generating a first compensation torque and a second compensation torque based on the pressure and displacement of the hydraulic pump respectively; generating a third compensation torque and a fourth compensation torque based on the speed of the engine and the speed of the ISG motor respectively; obtaining a fifth compensation torque based on a change in the engine speed and based on a PI control algorithm; screening out a maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque; summing the screened maximum value with the fifth compensation torque as the target compensation torque of the ISG motor, and controlling the ISG motor to perform torque compensation on the engine based on the target compensation torque of the ISG motor.

[0035] In some advantageous embodiments, a control method applicable to an excavator engine and an ISG motor according to the present invention may be implemented by a main controller of a control system applicable to an excavator engine and an ISG motor according to the present invention.

[0036] In a fourth aspect, the present invention provides a main controller suitable for an excavator engine and an ISG motor, wherein the main controller is configured to implement the following steps: obtaining the pressure and displacement of the hydraulic pump, and the speed of the ISG motor and the speed of the engine; generating a first compensation torque and a second compensation torque based on the pressure and displacement of the hydraulic pump respectively; generating a third compensation torque and a fourth compensation torque based on the speed of the engine and the speed of the ISG motor respectively; obtaining a fifth compensation torque based on the change in engine speed and based on a PI control algorithm; screening out the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque; summing the screened maximum value with the fifth compensation torque as the target compensation torque of the ISG motor, and controlling the ISG motor to perform torque compensation on the engine based on the target compensation torque of the ISG motor.

[0037] In some advantageous embodiments, a main controller applicable to an excavation engine and an ISG motor according to the present invention may be configured as a main controller of a control system applicable to an excavation engine and an ISG motor according to the present invention.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention generates a first compensation torque and a second compensation torque respectively based on the pressure and displacement of the hydraulic pump according to the sudden change of the hydraulic pump (i.e., the load); generates a third compensation torque and a fourth compensation torque based on the speed of the engine and the speed of the ISG motor according to the sudden change of the engine speed; and calculates the fifth compensation torque based on the engine speed change and the PI control algorithm according to the sudden change of the engine speed, screens out the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque, and sums the screened maximum value with the fifth compensation torque as the target compensation torque of the ISG motor, and controls the ISG motor to perform torque compensation on the engine based on the target compensation torque of the ISG motor, which can not only drive the engine to quickly return to the set speed, reduce the engine friction work, and improve the fuel saving rate, but also achieve multi-dimensional improvement of the ISG motor torque and speed control accuracy, as well as improve the speed and torque response speed and control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0041] FIG1 is a schematic diagram showing the principle of a control system applicable to an excavator engine and an ISG motor according to an embodiment of the present invention;

[0042] FIG2 is a schematic diagram of a control process of a control system applicable to an excavator engine and an ISG motor according to an embodiment of the present invention;

[0043] in:

[0044] 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 DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0047] Example 1

[0048] In an embodiment of the present invention, a control system for an excavator engine and an ISG motor is provided, the control system comprising: 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;

[0049] The sensor modules are connected to the engine 1, the ISG motor 2 and the hydraulic pump 3 respectively, and are configured to: collect the pressure and displacement of the hydraulic pump 3, and the speed of the ISG motor 2 and the speed of the engine 1;

[0050] The main controller 8 is connected to the sensor module, and the main controller is configured to: generate a first compensation torque and a second compensation torque based on the pressure and displacement of the hydraulic pump 3, respectively; generate a third compensation torque and a fourth compensation torque based on the speed of the engine 1 and the speed of the ISG motor 2, respectively; calculate the fifth compensation torque based on the change in engine speed and based on the PI control algorithm; filter out the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque, sum the filtered maximum value with the fifth compensation torque as the target compensation torque of the ISG motor, and control the ISG motor 2 to perform torque compensation on the engine 1 based on the target compensation torque of the ISG motor.

[0051] In a specific implementation of the embodiment of the present invention, the main controller 8 is configured to: calculate the engine speed change Δn1 based on the engine speed N1, and apply Δn1=f(N1);

[0052] When the engine speed change Δn1 is greater than the set threshold, the ISG motor target compensation torque is calculated;

[0053] In another specific implementation of the embodiment of the present invention, the main controller 8 is configured to: calculate the hydraulic pump pressure difference Δp based on the actual hydraulic pump pressure p1 collected by the sensor module, and apply Δp=f(p1);

[0054] When the hydraulic pump pressure difference Δp is greater than the set threshold, the ISG motor target compensation torque is calculated.

[0055] In a specific implementation of the 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;

[0056] 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;

[0057] 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;

[0058] 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;

[0059] 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.

[0060] The main controller 8 includes a load feedforward controller 10 and an engine feedforward controller 11 .

[0061] The load feedforward controller is configured such that when the excavator operation is obstructed and the pressure of the hydraulic pump 3 rises sharply, resulting in a hydraulic pump pressure difference Δp, if the hydraulic pump pressure difference Δp is greater than a set threshold, the load feedforward controller 10 calculates a first compensation torque. The calculation formula of the first compensation torque is:

[0062] Among them, 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, 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 current I1 of the hydraulic pump collected by the sensor module, and V1=f(I1) applies.

[0063] The load feedforward controller is configured such that when the hydraulic pump 3 suddenly accelerates and the displacement of the hydraulic pump 3 increases sharply, resulting in a hydraulic pump displacement difference ΔV, if the hydraulic pump displacement difference ΔV is greater than a set threshold, the load feedforward controller 10 calculates a second compensation torque. The calculation formula for the second compensation torque is:

[0064] Wherein, T2 is the first compensation torque, K2 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 acquired by the sensor module.

[0065] The engine feedforward controller is configured such that when the excavator operation is blocked and the pressure of the hydraulic pump 3 rises sharply to generate a hydraulic pump pressure difference Δp, the engine speed suddenly drops Δn due to the increase in engine pressure. f1 , the third compensation torque is calculated by the engine feedforward controller 11, and the calculation formula of the third compensation torque is:

[0066] Wherein, T3 is the third compensation torque, K3 is the pressure compensation coefficient of the engine feedforward controller 11, P ISG is the power of ISG motor 2.

[0067] The engine feedforward controller is configured such that when the hydraulic pump 3 suddenly accelerates and the hydraulic pump displacement increases sharply to generate a hydraulic pump displacement difference ΔV, the engine 1 displacement increases and the speed suddenly drops Δn. f2 , the engine feedforward controller 11 calculates the fourth compensation torque, and the calculation formula of the fourth compensation torque is:

[0068] Wherein, T4 is the fourth compensation torque, K4 is the displacement compensation coefficient of the engine feedforward controller 11, P ISG is the power of ISG motor 2.

[0069] The main controller is configured to obtain a proportional control parameter K based on the hydraulic pump pressure difference Δp and the hydraulic pump displacement difference ΔV. p MAP value table;

[0070] The main controller 8 is configured to find the corresponding proportional control parameter K according to the detected hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV. p ;

[0071] The main controller 8 is configured to start the integral control K when the absolute value of the difference Δn2 between the actual engine speed and the target speed is less than a set threshold. i , when the integral value Exceeding Ki limit UpL , only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL When , only positive deviations are accumulated; is the integral calculation value, e(t) is the cumulative integral function about the difference Δn2, and t is the integration time; Ki UpL is the upper limit of the integral, Ki DownL is the lower limit of the integral;

[0072] Finally, the fifth compensation torque T5 is calculated.

[0073] The working process of the control system applicable to the excavator engine and the ISG motor in the embodiment of the present invention will be described in detail below with reference to FIG. 2 and a specific implementation manner.

[0074] Considering that the external load is random and changeable during the operation of the excavator, the engine 1 often slows down or speeds up, and it takes too long to return to normal. Therefore, it is necessary to calculate the required torque and speed, control the ISG motor 2 to compensate the torque of the engine 1, and quickly restore the engine speed to the optimal fuel consumption zone to reduce operating fuel consumption.

[0075] To this end, an embodiment of the present invention proposes a control system suitable for an excavator engine and an ISG motor. During actual use, the control system executes the following process:

[0076] S1: Collect data, calculate engine speed, and determine whether to start torque compensation instruction

[0077] The vehicle controller collects the engine speed n1, and the control program calculates the engine speed change Δn1=f(n1). In the specific implementation process, the engine speed change can be obtained by subtracting the speed value at the next moment from the speed value at the previous moment.

[0078] The absolute value of the engine speed change Δn1 is determined to be greater than a set threshold. If the engine speed change Δn1 is greater than the set threshold, the torque compensation command is activated. To avoid frequent activation of the command, based on test data analysis, the reference speed threshold is set to, for example, 30 r / min.

[0079] 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 of the hydraulic pump and the actual current I1 of the hydraulic pump. According to the current and displacement conversion formula of the hydraulic pump 3 (measured by experiment), the actual displacement V1 of the hydraulic pump is calculated, V1=f(I1), and the hydraulic pump pressure difference Δp, Δp=f(p1).

[0080] It is determined whether the absolute value of the hydraulic pump pressure difference Δp is greater than a set threshold. If Δp is greater than the set threshold, the torque compensation command is started.

[0081] The main controller 8 collects the ISG motor speed n ISG , ISG motor power P ISG .

[0082] S2: Power compensation for ISG motor 2 based on load pressure and displacement

[0083] When the excavator operation is obstructed, the pressure of the hydraulic pump 3 will rise sharply, generating a hydraulic pump pressure difference Δp (i.e., a pressure increase Δp). If the calculated hydraulic pump pressure difference Δp is greater than a set threshold, such as 2 MPa, the load feedforward controller 10 calculates a first compensation torque. The calculation formula of the first compensation torque is:

[0084] Wherein, T1 is the first compensation torque (i.e., the compensation torque T1 in FIG2 ), K1 is the pressure compensation coefficient of the load feedforward controller 10 , Δp is the pressure difference of the hydraulic pump, 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 current I1 of the hydraulic pump collected by the sensor module, and V1=f(I1);

[0085] When the hydraulic system suddenly accelerates, generating a hydraulic pump displacement difference ΔV (i.e., the hydraulic pump displacement increases by ΔV), and the calculated hydraulic pump displacement difference ΔV is greater than a set threshold, such as 10cc / rev, the load feedforward controller 10 calculates a second compensation torque. The calculation formula for the second compensation torque is:

[0086] Among them, T2 is the second compensation torque (i.e., the compensation torque T2 in Figure 2), 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 collected by the sensor module.

[0087] S3: Torque compensation for ISG motor 2 according to engine speed

[0088] When the excavator is blocked, the pressure of the hydraulic pump 3 will rise sharply, resulting in a hydraulic pump pressure difference Δp (i.e., pressure increase Δp). Due to the pressure increase, the speed of the engine 1 suddenly drops Δn f1 In order to return the engine speed to the set value, the engine feedforward controller 11 calculates the third compensation torque. The calculation formula of the third compensation torque is:

[0089] Wherein, T3 is the third compensation torque (ie, the compensation torque T3 in FIG2 ), K3 is the pressure compensation coefficient of the engine feedforward controller 11, and P ISG is the power of ISG motor 2.

[0090] When the hydraulic system suddenly accelerates, the hydraulic pump displacement will increase sharply, resulting in a hydraulic pump displacement difference ΔV (i.e., the hydraulic pump displacement increases by ΔV). As the displacement increases, the speed of the engine 1 suddenly drops by Δn. f2 In order to return the engine speed to the set value, the engine feedforward controller 11 calculates the fourth compensation torque. The calculation formula of the fourth compensation torque is:

[0091] Wherein, T4 is the fourth compensation torque (ie, the compensation torque T4 in FIG2 ), K4 is the displacement compensation coefficient of the engine feedforward controller 11, and P ISG is the power of ISG motor 2.

[0092] S4: Closed-loop speed control of ISG motor 2 according to load

[0093] When the excavator is blocked, the hydraulic system pressure rises sharply, and the load-side power demand increases. In order to maintain the engine speed, the output torque of Engine 1 needs to be increased. Due to the increased load, the speed of Engine 1 suddenly drops. Through PI control, ISG motor 2 increases the 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. Based on the hydraulic pump pressure difference Δp, the hydraulic pump displacement difference ΔV and actual test experience, a proportional control parameter K is created. p 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 poor control effect, when the absolute value of the difference Δn2 between the actual speed and the target speed is less than, for example, 5rev / min, the integral control K is started. i , in addition, when the integral value Exceeding Ki limit UpL , only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL When , only positive deviations are accumulated; is the integral calculation value, e(t) is the cumulative integral function about the difference Δn1, and t is the integration time; Ki UpL is the upper limit of the integral, is the experience value, not given here, Ki DownL is the lower limit of the integral, which is an empirical value and is not given here. The fifth compensation torque T5 (i.e., the compensation torque T5 in FIG2 ) is finally calculated and output.

[0094] The maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque is screened out, and the sum of the maximum value with the fifth 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, so that the engine speed is quickly restored to the optimal fuel consumption zone, thereby reducing operating fuel consumption.

[0095] Example 2

[0096] An embodiment of the present invention provides a control method applicable to an excavator engine and an ISG motor, comprising the following steps:

[0097] (1) Using the sensor module, 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 respectively;

[0098] (2) Using the main controller 8, a first compensation torque and a second compensation torque are generated based on the pressure and displacement of the hydraulic pump 3, respectively; a third compensation torque and a fourth compensation torque are generated based on the speed of the engine 1 and the speed of the ISG motor 2, respectively; a fifth compensation torque is calculated based on the change in engine speed and based on the PI control algorithm; the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque is screened out, the screened maximum value is summed with the fifth compensation torque as the target compensation torque of the ISG motor, and the ISG motor 2 is controlled to perform torque compensation on the engine 1 based on the target compensation torque of the ISG motor.

[0099] In a specific implementation of the embodiment of the present invention, the main controller 8 calculates the engine speed change Δn1 based on the engine speed n1, Δn1 = f(n1);

[0100] When the engine speed change Δn1 is greater than the set threshold, the ISG motor target compensation torque is calculated;

[0101] In another specific implementation of the 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, Δp=f(p1);

[0102] When the hydraulic pump pressure difference Δp is greater than the set threshold, the ISG motor target compensation torque is calculated.

[0103] In a specific implementation of the 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;

[0104] 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;

[0105] 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;

[0106] 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;

[0107] 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.

[0108] The main controller 8 includes a load feedforward controller 10 and an engine feedforward controller 11 .

[0109] When the excavator operation is obstructed, the pressure of the 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 load feedforward controller 10 calculates a first compensation torque. The calculation formula of the first compensation torque is:

[0110] Among them, 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, 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 current I1 of the hydraulic pump collected by the sensor module, V1=f(I1).

[0111] When the hydraulic pump 3 suddenly accelerates, the displacement of the hydraulic pump 3 increases sharply, resulting in a hydraulic pump displacement difference ΔV. If the hydraulic pump displacement difference ΔV is greater than a set threshold, the load feedforward controller 10 calculates a second compensation torque. The calculation formula of the second compensation torque is:

[0112] Wherein, T2 is the first compensation torque, K2 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 acquired by the sensor module.

[0113] When the excavator is blocked, the pressure of the hydraulic pump 3 will rise sharply, resulting in a hydraulic pump pressure difference Δp. Due to the increase in engine pressure, the engine speed suddenly drops Δn. f1 , the third compensation torque is calculated by the engine feedforward controller 11, and the calculation formula of the third compensation torque is:

[0114] Wherein, T3 is the third compensation torque, K3 is the pressure compensation coefficient of the engine feedforward controller 11, P ISG is the power of ISG motor 2.

[0115] When the hydraulic pump 3 suddenly accelerates, the hydraulic pump displacement increases sharply, resulting in a hydraulic pump displacement difference ΔV. Due to the increase in the displacement of the engine 1, the speed suddenly drops Δn. f2 , the engine feedforward controller 11 calculates the fourth compensation torque, and the calculation formula of the fourth compensation torque is:

[0116] Wherein, T4 is the fourth compensation torque, K4 is the displacement compensation coefficient of the engine feedforward controller 11, P ISG is the power of ISG motor 2.

[0117] Get 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;

[0118] The main controller 8 is configured to find the corresponding proportional control parameter K according to the detected hydraulic pump pressure difference Δp and hydraulic pump displacement difference ΔV. p ;

[0119] When the absolute value of the difference Δn2 between the actual engine speed and the target speed is less than the set threshold, the integral control K is started. i , when the integral value Exceeding Ki limit UpL , only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL When , only positive deviations are accumulated; is the integral calculation value, e(t) is the cumulative integral function about the difference Δn2, and t is the integration time; Ki UpL is the upper limit of the integral, Ki DownL is the lower limit of the integral;

[0120] Finally, the fifth compensation torque T5 is calculated.

[0121] The working process of the control method applicable to the excavator engine and the ISG motor in the embodiment of the present invention will be described in detail below with reference to FIG. 2 and a specific implementation manner.

[0122] Considering that the external load is random and changeable during the operation of the excavator, the engine 1 often slows down or speeds up, and it takes too long to return to normal. Therefore, it is necessary to calculate the required torque and speed, control the ISG motor 2 to compensate the torque of the engine 1, and quickly restore the engine speed to the optimal fuel consumption zone to reduce operating fuel consumption.

[0123] To this end, an embodiment of the present invention proposes a control method applicable to an excavator engine and an ISG motor. In actual use, the control method performs the following process:

[0124] S1: Collect data, calculate engine speed, and determine whether to start torque compensation instruction

[0125] The vehicle controller collects the engine speed n1, and the control program calculates the engine speed change Δn1=f(n1). In the specific implementation process, the engine speed change can be obtained by subtracting the speed value at the next moment from the speed value at the previous moment.

[0126] The absolute value of the engine speed change Δn1 is determined to be greater than a set threshold. If the engine speed change Δn1 is greater than the set threshold, the torque compensation command is activated. To avoid frequent activation of the command, based on test data analysis, the reference speed threshold is set to, for example, 30 r / min.

[0127] 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 of the hydraulic pump and the actual current I1 of the hydraulic pump. According to the current and displacement conversion formula of the hydraulic pump 3 (measured by experiment), the actual displacement V1 of the hydraulic pump is calculated, V1=f(I1), and the hydraulic pump pressure difference Δp, Δp=f(p1).

[0128] It is determined whether the absolute value of the hydraulic pump pressure difference Δp is greater than a set threshold. If Δp is greater than the set threshold, the torque compensation command is started.

[0129] The main controller 8 collects the ISG motor speed n ISG , ISG motor power P ISG .

[0130] S2: Power compensation for ISG motor 2 based on load pressure and displacement

[0131] When the excavator operation is obstructed, the pressure of the hydraulic pump 3 will rise sharply, resulting in a hydraulic pump pressure difference Δp (i.e., a pressure increase Δp). When the calculated hydraulic pump pressure difference Δp is greater than a set threshold, such as 2 MPa, the load feedforward controller 10 calculates a first compensation torque. The calculation formula of the first compensation torque is:

[0132] Wherein, T1 is the first compensation torque (i.e., the compensation torque T1 in FIG2 ), K1 is the pressure compensation coefficient of the load feedforward controller 10 , Δp is the pressure difference of the hydraulic pump, 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 current I1 of the hydraulic pump collected by the sensor module, and V1=f(I1) applies.

[0133] When the hydraulic system suddenly accelerates, generating a hydraulic pump displacement difference ΔV (i.e., the hydraulic pump displacement increases by ΔV), the calculated hydraulic pump displacement difference ΔV is greater than a set threshold, such as 10cc / rev. Then, the load feedforward controller 10 calculates a second compensation torque. The calculation formula for the second compensation torque is:

[0134] Among them, T2 is the second compensation torque (i.e., the compensation torque T2 in Figure 2), 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 collected by the sensor module.

[0135] S3: Torque compensation for ISG motor 2 according to engine speed

[0136] When the excavator is blocked, the pressure of the hydraulic pump 3 will rise sharply, resulting in a hydraulic pump pressure difference Δp (i.e., pressure increase Δp). Due to the pressure increase, the speed of the engine 1 suddenly drops Δn f1 In order to return the engine speed to the set value, the engine feedforward controller 11 calculates the third compensation torque. The calculation formula of the third compensation torque is:

[0137] Wherein, T3 is the third compensation torque (ie, the compensation torque T3 in FIG2 ), K3 is the pressure compensation coefficient of the engine feedforward controller 11, and P ISG is the power of ISG motor 2.

[0138] When the hydraulic system suddenly accelerates, the hydraulic pump displacement will increase sharply, resulting in a hydraulic pump displacement difference ΔV (i.e., the hydraulic pump displacement increases by ΔV). As the displacement increases, the speed of the engine 1 suddenly drops by Δn. f2 In order to return the engine speed to the set value, the engine feedforward controller 11 calculates the fourth compensation torque. The calculation formula of the fourth compensation torque is:

[0139] Wherein, T4 is the fourth compensation torque (ie, the compensation torque T4 in FIG2 ), K4 is the displacement compensation coefficient of the engine feedforward controller 11, and P ISG is the power of ISG motor 2.

[0140] S4: Closed-loop speed control of ISG motor 2 according to load

[0141] When the excavator is blocked, the hydraulic system pressure rises sharply, and the load-side power demand increases. In order to maintain the engine speed, the output torque of Engine 1 needs to be increased. Due to the increased load, the speed of Engine 1 suddenly drops. Through PI control, ISG motor 2 increases the 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. Based on the hydraulic pump pressure difference Δp, the hydraulic pump displacement difference ΔV and actual test experience, a proportional control parameter K is created. p 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 poor control effect, when the absolute value of the difference Δn2 between the actual speed and the target speed is less than 5rev / min, the integral control K is started. i , in addition, when the integral value Exceeding Ki limitUpL , only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL When , only positive deviations are accumulated; is the integral calculation value, e(t) is the cumulative integral function about the difference Δn1, and t is the integration time; Ki UpL is the upper limit of the integral, is the experience value, not given here, Ki DownL is the lower limit of the integral, which is an empirical value and is not given here. The fifth compensation torque (i.e., the compensation torque T5 in FIG2 ) is finally calculated and output.

[0142] The maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque is screened out, and the sum of the maximum value with the fifth 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, so that the engine speed is quickly restored to the optimal fuel consumption zone, thereby reducing operating fuel consumption.

[0143] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0144] The present application is described with reference to the flow chart and / or block diagram of the method, device (system), and computer program product according to the embodiment of the present application. It should be understood that each flow process and / or box in the flow chart and / or block diagram and the combination of the flow process and / or box in the flow chart and / or block diagram can be realized by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processing machine or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for realizing the function specified in one flow chart flow or multiple flows and / or one box or multiple boxes of the block diagram.

[0145] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0146] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0147] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all protected by the present invention.

[0148] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A control system suitable for an excavator engine and an ISG motor, characterized in that: The control system includes: an engine, an ISG motor, a hydraulic pump, a sensor module and a main controller; The sensor modules are connected to the engine, the ISG motor and the hydraulic pump respectively, and the sensor modules are configured to: collect the pressure and displacement of the hydraulic pump, the rotation speed of the ISG motor and the rotation speed of the engine; The main controller is connected to the sensor module, and the main controller is configured to: generate a first compensation torque and a second compensation torque based on the pressure and displacement of the hydraulic pump, respectively; generate a third compensation torque and a fourth compensation torque based on the engine speed and the speed of the ISG motor, respectively; calculate the fifth compensation torque based on the engine speed change and based on the PI control algorithm; filter out the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque, sum the filtered maximum value with the fifth compensation torque as the ISG motor target compensation torque, and control the ISG motor to perform torque compensation on the engine based on the ISG motor target compensation torque.

2. A control system suitable for an excavator engine and an ISG motor according to claim 1, characterized in that: The main controller is configured to: calculate the engine speed change Δn1 based on the engine speed n1, and apply Δn1=f(n1); And when the engine speed change Δn1 is greater than the set threshold, the ISG motor target compensation torque is calculated; Alternatively, the main controller is configured to: calculate the hydraulic pump pressure difference Δp based on the actual hydraulic pump pressure p1 acquired by the sensor module, and apply Δp=f(p1); And when the hydraulic pump pressure difference Δp is greater than the set threshold, the ISG motor target compensation torque is calculated.

3. A control system suitable for an excavator engine and an ISG motor 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 the engine and the main controller respectively; The ISG motor speed sensor is connected to the ISG motor and the main controller respectively; The current sensor is connected to the hydraulic pump and the main controller respectively; The pressure sensors are connected to the hydraulic pump and the main controller respectively.

4. A control system suitable for an excavator engine and an ISG motor according to any one of claims 1 to 3, characterized in that: The main controller includes a load feedforward controller and an engine feedforward controller.

5. A control system suitable for an excavator engine and an ISG motor according to claim 4, characterized in that: The load feedforward controller is configured such that: when the operation of the excavator is obstructed and the pressure of the hydraulic pump rises sharply to generate a hydraulic pump pressure difference Δp, if the hydraulic pump pressure difference Δp is greater than a set threshold, the load feedforward controller calculates a first compensation torque, and the calculation formula of the first compensation torque is: Among them, T1 is the first compensation torque, K1 is the pressure compensation coefficient of the load feedforward controller, Δp is the hydraulic pump pressure difference; V1 is the actual displacement of the hydraulic pump, wherein V1 is calculated by the main controller based on the actual current I1 of the hydraulic pump collected by the sensor module, and V1=f(I1) applies.

6. A control system suitable for an excavator engine and an ISG motor according to claim 4, characterized in that: The load feedforward controller is configured such that: when the hydraulic pump suddenly accelerates and the displacement of the hydraulic pump rises sharply to generate a hydraulic pump displacement difference ΔV, if the hydraulic pump displacement difference ΔV is greater than a set threshold, the load feedforward controller calculates a second compensation torque, and the calculation formula of the second compensation torque is: Among them, T2 is the first compensation torque, K2 is the displacement compensation coefficient of the load feedforward controller, ΔV is the hydraulic pump displacement difference; p1 is the actual pressure of the hydraulic pump, which is collected by the sensor module.

7. A control system suitable for an excavator engine and an ISG motor according to claim 4, characterized in that: The engine feedforward controller is configured such that when the excavator operation is blocked and the pressure of the hydraulic pump rises sharply to generate a hydraulic pump pressure difference Δp, the engine speed suddenly drops Δn due to the increase in engine pressure. f1 , the third compensation torque is calculated by the engine feedforward controller, and the calculation formula of the third compensation torque is: Wherein, T3 is the third compensation torque, K3 is the pressure compensation coefficient of the engine feedforward controller, P ISG is the power of the ISG motor.

8. A control system suitable for an excavator engine and an ISG motor according to claim 4, characterized in that: The engine feedforward controller is configured such that when the hydraulic pump suddenly accelerates and the hydraulic pump displacement increases sharply to generate a hydraulic pump displacement difference ΔV, the engine speed suddenly decreases Δn due to the increase in engine displacement. f2 , the fourth compensation torque is calculated by the engine feedforward controller, and the calculation formula of the fourth compensation torque is: Wherein, T4 is the fourth compensation torque, K4 is the displacement compensation coefficient of the engine feedforward controller, P ISG is the power of the ISG motor.

9. A control system suitable for an excavator engine and an ISG motor according to claim 4, characterized in that: The main controller is configured to obtain a proportional control parameter K created according to the hydraulic pump pressure difference Δp and the hydraulic pump displacement difference ΔV. p MAP value table; according to the detected hydraulic pump pressure difference Δp, hydraulic pump displacement difference ΔV, find the corresponding proportional control parameter K p ; The main controller is configured to start the integral control K when the absolute value of the difference Δn2 between the actual engine speed and the target speed is less than a set threshold. i , when the integral value Exceeding Ki limit UpL , only negative deviations are accumulated; when the integral value Exceeding the lower limit Ki DownL When , only positive deviations are accumulated; is the integral calculation value, e(t) is the cumulative integral function about the difference Δn2, and t is the integration time; Ki UpL is the upper limit of the integral, Ki DownL is the lower limit of the integral; Finally, the fifth compensation torque T5 is calculated:

10. A control method for an excavator engine and an ISG motor, characterized in that: The control method comprises: The sensor module is used to collect the pressure and displacement of the hydraulic pump, the speed of the ISG motor and the speed of the engine; Using a main controller, a first compensation torque and a second compensation torque are respectively generated based on the pressure and displacement of the hydraulic pump; a third compensation torque and a fourth compensation torque are respectively generated based on the speed of the engine and the speed of the ISG motor; a fifth compensation torque is calculated based on the change in engine speed and based on a PI control algorithm; the maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque is screened out, the screened maximum value and the fifth compensation torque are summed as the target compensation torque of the ISG motor, and the ISG motor is controlled to perform torque compensation on the engine based on the target compensation torque of the ISG motor.

11. A control method for an excavator engine and an ISG motor according to claim 10, characterized in that , the control method is implemented by a control system according to one of claims 1 to 9.

12. A control method for an excavator engine and an ISG motor, characterized in that: The control method comprises: Get the pressure and displacement of the hydraulic pump, as well as the speed of the ISG motor and the speed of the engine; generating a first compensation torque and a second compensation torque based on the pressure and displacement of the hydraulic pump, respectively; Generate a third compensation torque and a fourth compensation torque based on the speed of the engine and the speed of the ISG motor respectively; A fifth compensation torque is calculated based on the engine speed change and the PI control algorithm; Screening out a maximum value among the first compensation torque, the second compensation torque, the third compensation torque and the fourth compensation torque; The screened maximum value and the fifth compensation torque are summed as the ISG motor target compensation torque, and the ISG motor is controlled to perform torque compensation on the engine based on the ISG motor target compensation torque.

13. A control method for an excavator engine and an ISG motor according to claim 12, characterized in that , the control method is implemented by a main controller of a control system according to one of claims 1 to 9.

14. A main controller suitable for an excavator engine and an ISG motor, characterized in that: The main controller is configured to implement the control method according to claim 12 .

15. The main controller according to claim 14, characterized in that: The main controller is configured as a main controller of a control system according to one of claims 1 to 9.

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