A diesel engine speed cascade anti-disturbance control system, diesel engine and locomotive

Abstract

The present disclosure relates to a diesel engine speed cascade auto-disturbance rejection control system, a diesel engine and a locomotive. The system comprises: a feedforward controller, an inner-loop auto-disturbance rejection controller and an outer-loop auto-disturbance rejection controller connected in sequence; wherein the inner-loop auto-disturbance rejection controller specifically comprises: a nonlinear error feedback controller and an extended state observer; the extended state observer is used to observe model deviations and external disturbances, and to provide real-time feedback compensation for the control quantity according to the observed value of the total disturbance; the nonlinear error feedback controller is used to track the signal transmitted from the outer loop; wherein the outer loop controller comprises: an error feedback controller and an extended state observer for tracking the target speed.

Description

Technical Field

[0001] The present disclosure relates to the technical field of diesel engine control, and more specifically, to a diesel engine speed cascade anti-disturbance control system, a diesel engine and a locomotive. Background Art

[0002] Precise speed control of non-road diesel engines is the key to the quality of power supply. Diesel engines for power generation will encounter sudden changes and large load access during actual use and factory verification. Traditional pure feedback control has poor control robustness under the condition of sudden large load, and the speed will fluctuate greatly, making it difficult to adapt to power generation requirements. Summary of the invention

[0003] To solve the technical problem that the existing pure feedback control has poor control robustness and large fluctuations in speed under the condition of sudden large load, making it difficult to adapt to power generation requirements.

[0004] In order to achieve the above technical objectives, the present disclosure provides a diesel engine speed cascade active disturbance rejection control system, comprising:

[0005] A feedforward controller, an inner loop anti-disturbance controller and an outer loop controller connected in sequence;

[0006] The inner loop anti-disturbance control system specifically includes: a nonlinear error feedback controller and an extended state observer;

[0007] The extended state observer is used to observe the model deviation and external disturbance, and to provide real-time feedback compensation for the control amount according to the observed value of the total disturbance;

[0008] The nonlinear error feedback controller is used to track the signal from the outer loop;

[0009] Wherein, the outer loop controller includes: an error feedback controller and an extended state observer for tracking the target speed.

[0010] Furthermore, the feedforward controller is specifically obtained by constructing a dynamic model of the speed of a diesel engine for power generation;

[0011] The speed dynamic model of the diesel engine for power generation is composed of an indicated torque model, a friction torque model, a pumping torque model and a load torque model.

[0012] Furthermore, the dynamic model of the speed of the diesel engine for power generation is expressed as:

[0013]

[0014] Where W is the speed, M is i is the indicative torque model, M Fri is the friction torque model, Mp is the pump torque model, M load The load torque model is substituted into the indicated torque model, friction torque model, pump torque model and load torque model into the speed dynamic model of the diesel engine for power generation, and the following expression is obtained:

[0015]

[0016] Among them, H HLV is the lower calorific value, η i To indicate thermal efficiency, C i is the self-learning parameter, i=1,2,……,5,T oil is the oil temperature;

[0017] And the expression is sorted out to get:

[0018]

[0019] Further, the extended state observer is designed after the expression is sorted out;

[0020] Wherein a0, b0, f0 are obtained according to the expression, and f is an unknown expression;

[0021] Assume f is continuously differentiable and bounded;

[0022] ω is the differential of f, and the extended state observer is designed for the system:

[0023]

[0024]

[0025] Where z1 and z2 observe W and f respectively, e1=z1-W, β1 and β2 represent the time-invariant parameters of two adjustable observers, and δ1 is a given parameter.

[0026]

[0027] Furthermore, the nonlinear error feedback controller is constructed by the following formula:

[0028] u=(a1fal(ξ,0.5,δ1)-f0-z2) / b0;

[0029] The error value is ξ=ν-z1, where ν is the acceleration value transferred by the outer loop, z1 is the observed value of the acceleration by the extended state observer, a1 represents the gain of the nonlinear controller, and z2 / b0 is the compensation amount of f.

[0030] Further, the output value of the outer loop controller is the input target value of the inner loop ADRC;

[0031] Rewrite the model as:

[0032] Among them, a0, b1, f0 can be obtained by transforming the formula;

[0033] Define e3=z3-x1 and design the extended state observer as

[0034] z3=z4-β1e3+f+b1u;

[0035] z4=-β2fal(e3,0.5,δ2);

[0036] Where z3, z4 are the observed values ​​of states x1, x2, and δ2 is the given parameter.

[0037] Furthermore, the error feedback controller is constructed in the following manner:

[0038] Let the error signal be ε=ρ-z3, where ρ is the target speed and z3 is the angle observation value of the extended state observer. The nonlinear error feedback controller is constructed as:

[0039] ν=(a2fal(ε,0.5,δ3)-f-z4) / b1. , where a2 is the gain of the nonlinear controller and z4 / b1 is the compensation amount of f.

[0040] In order to achieve the above technical objectives, the present disclosure can also provide a diesel engine equipped with the above diesel engine speed cascade anti-disturbance control system.

[0041] In order to achieve the above technical objectives, the present disclosure also provides a locomotive equipped with the above diesel engine.

[0042] The beneficial effects of the present disclosure are:

[0043] The present invention discloses a cascaded anti-disturbance control method based on a speed dynamic model, making full use of the model information of the system to make the control process more accurate; designs an extended state observer, regards the total disturbance as the extended state of the system for estimation and prediction, actively suppresses disturbances, and improves the anti-disturbance capability; reduces product development costs, and generally achieves accurate speed control of diesel engines for power generation.

[0044] The method disclosed in the present invention is easy to design, has simple parameter adjustment and strong robustness, reduces the calibration time by more than 80% compared with the existing algorithm, improves the anti-interference ability by more than 30%, and effectively improves the speed control accuracy of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic diagram showing Embodiment 1 of the present disclosure is shown. DETAILED DESCRIPTION

[0046] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0047] Various structural schematic diagrams according to embodiments of the present disclosure are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may further design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0048] Embodiment 1:

[0049] Explanation of professional terms involved in this disclosure:

[0050] ESO: Extended State Observer;

[0051] Active anti-disturbance control: The total disturbance of the system is estimated by the state observer and compensated in real time to build a disturbance suppressor, and the error feedback control is designed to correct the deviation between the actual value and the true value of the system output.

[0052] like Figure 1 As shown:

[0053] The present disclosure provides a diesel engine speed cascade auto-disturbance rejection control method, comprising:

[0054] A diesel engine speed cascade anti-disturbance control system, comprising:

[0055] A feedforward controller, an inner loop anti-disturbance controller and an outer loop controller connected in sequence;

[0056] The inner loop anti-disturbance control system specifically includes: a nonlinear error feedback controller and an extended state observer;

[0057] The extended state observer is used to observe the model deviation and external disturbance, and to provide real-time feedback compensation for the control amount according to the observed value of the total disturbance;

[0058] The nonlinear error feedback controller is used to track the signal transmitted from the outer ring speed;

[0059] Wherein, the outer loop controller includes: an error feedback controller and an extended state observer for tracking the target speed.

[0060] Furthermore, the feedforward controller is specifically obtained by constructing a dynamic model of the speed of a diesel engine for power generation;

[0061] The speed dynamic model of the diesel engine for power generation is composed of an indicated torque model, a friction torque model, a pumping torque model and a load torque model.

[0062] Furthermore, the dynamic model of the speed of the diesel engine for power generation is expressed as:

[0063]

[0064] Where W is the speed, M is i is the indicative torque model, M Fri is the friction torque model, M p is the pump torque model, M load The load torque model is substituted into the indicated torque model, friction torque model, pump torque model and load torque model into the speed dynamic model of the diesel engine for power generation, and the following expression is obtained:

[0065]

[0066] Among them, H HLV is the lower calorific value, η i To indicate thermal efficiency, C i is the self-learning parameter, i=1,2,……,5,T oil is the oil temperature;

[0067] And the expression is sorted out to get:

[0068]

[0069] Further, the extended state observer is designed after the expression is sorted out;

[0070] Wherein a0, b0, f0 are obtained according to the expression, and f is an unknown expression;

[0071] Assume f is continuously differentiable and bounded;

[0072] ω is the differential of f, and the extended state observer is designed for the system:

[0073]

[0074]

[0075] Where z1 and z2 observe W and f respectively, e1=z1-W, β1 and β2 represent the time-invariant parameters of two adjustable observers, and δ1 is a given parameter.

[0076]

[0077] Furthermore, the nonlinear error feedback controller is constructed by the following formula:

[0078] u=(a1fal(ξ,0.5,δ1)-f0-z2) / b0;

[0079] The error value is ξ=ν-z1, where ν is the acceleration value transferred by the outer loop, z1 is the observed value of the acceleration by the extended state observer, a1 represents the gain of the nonlinear controller, and z2 / b0 is the compensation amount of f.

[0080] Further, the output value of the outer loop controller is the input target value of the inner loop ADRC;

[0081] Rewrite the model as:

[0082] Among them, a0, b1, f0 can be obtained by transforming the formula;

[0083] Define e3=z3-x1 and design the extended state observer as

[0084] z3=z4-β1e3+f+b1u;

[0085] z4=-β2fal(e3,0.5,δ2);

[0086] Where z3, z4 are the observed values ​​of states x1, x2, and δ2 is the given parameter.

[0087] Furthermore, the error feedback controller is constructed in the following manner:

[0088] Let the error signal be ε=ρ-z3, where ρ is the target speed and z3 is the angle observation value of the extended state observer. The nonlinear error feedback controller is constructed as:

[0089] ν=(a2fal(ε,0.5,δ3)-f-z4) / b1. , where a2 is the gain of the nonlinear controller and z4 / b1 is the compensation amount of f.

[0090] In view of the problem that when the current diesel engine for power generation uses PID algorithm to control the speed only through feedback regulation, the speed will fluctuate greatly when encountering sudden changes or large load access, and the system adjustment time is long, the present invention adopts a cascade self-disturbance rejection control method based on a speed dynamic model to achieve precise speed control of the diesel engine for power generation.

[0091] Figure 1 The overall block diagram of the cascaded active disturbance rejection control algorithm is shown in Figure 1 Where ρ(t) is the target speed, ε(t) is the deviation between the target speed and the actual speed, ζ(t) is the deviation between the target acceleration and the current acceleration, and W(t) is the actual speed.

[0092] The specific implementation plan is as follows:

[0093] 1. Build a feedforward controller based on the speed dynamic model

[0094] A dynamic model of diesel engine speed for power generation is established. The model mainly consists of four parts: indicated torque model, friction torque model, pump torque model and load torque model.

[0095]

[0096] Where W is the speed, M is i is the indicative torque model, M Fri is the friction torque model, M p is the pump torque model, M load is the load torque model. Substitute the indicated torque model, friction torque model, pump torque model and load torque model into the speed dynamic model to obtain the following expression:

[0097]

[0098] Among them, H HLV is the lower calorific value, η i To indicate thermal efficiency, C i is the self-learning parameter, T oil For oil temperature.

[0099] In order to facilitate controller design, equation (2) is rearranged and converted into equation (3):

[0100]

[0101] 2. Design of inner loop anti-disturbance controller

[0102] 1) Extended State Observer Design

[0103] There is a deviation in the model during the establishment of the speed dynamic model, so the torque compensation of the feedforward model cannot fully represent the actual torque demand. Furthermore, the torque part of the power load cannot be accurately expressed through the simulation of physical modeling. Therefore, an extended state observer is designed to observe the model deviation and external disturbance in real time, and to provide real-time feedback compensation for the control quantity based on the observed value of the total disturbance.

[0104] To facilitate observer design, equation (2) is rearranged to obtain the first-order expression of speed dynamics:

[0105]

[0106] Among them, a0, b0, f0 can be obtained according to formula (3), Mainly model deviation and load torque, etc. f is unknown, and its value and expression are unknown. Assuming that the nonlinear part f is continuously differentiable and bounded, ω is the differential of f, and an extended state observer is designed for the system.

[0107]

[0108]

[0109] Where z1 and z2 observe W and f respectively, e1=z1-W, β1 and β2 represent the time-invariant parameters of two adjustable observers, and δ1 is a given parameter.

[0110]

[0111] 2) Design of nonlinear error feedback controller

[0112] In order to track the signal from the outer ring speed, this section designs a nonlinear error feedback controller, whose error value is ξ = ν-z1, where ν is the acceleration value transmitted by the outer ring, and z1 is the observed value of the acceleration by the extended state observer. The following nonlinear state error feedback controller is constructed

[0113] u=(a1fal(ξ,0.5,δ1)-f0-z2) / b0 (7)

[0114] Where a1 represents the gain of the nonlinear controller, and z2 / b0 is the compensation amount of f.

[0115] 2. Outer loop controller design

[0116] The outer loop of this control system also adopts the anti-disturbance controller, ρ is the given speed, ε is the deviation between the target speed and the actual speed, that is,

[0117] ε=ρ-W (8)

[0118] have Figure 1 It can be obtained that the output value of the outer loop is the input target value of the inner loop. The outer loop rewrites the above model as

[0119]

[0120] Define e3=z3-x1 and design the extended state observer as

[0121] z3=z4-β1e3+f+b1u (10)

[0122] z4=-β2fal(e3,0.5,δ2) (11)

[0123] Where z3, z4 are the observed values ​​of states x1, x2, and δ2 is the given parameter.

[0124] In order to track the target speed, an error feedback controller is designed. Let the error signal be ε = ρ-z3, where ρ is the target speed and z3 is the angle observation value of the extended state observer. The nonlinear error feedback controller is constructed as

[0125] ν=(a2fal(ε,0.5,δ3)-f-z4) / b1 (12)

[0126] Where a2 is the gain of the nonlinear controller, and z4 / b1 is the compensation amount of f.

[0127] In order to achieve the above technical objectives, the present disclosure can also provide a diesel engine equipped with the above diesel engine speed cascade anti-disturbance control system.

[0128] In order to achieve the above technical objectives, the present disclosure also provides a locomotive equipped with the above diesel engine.

[0129] The embodiments of the present disclosure are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, a person skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A diesel engine speed cascade active disturbance rejection control system, characterized in that: include: A feedforward controller, an inner loop anti-disturbance controller and an outer loop controller connected in sequence; The inner loop anti-disturbance control controller specifically includes: a nonlinear error feedback controller and an extended state observer; The extended state observer is used to observe the model deviation and external disturbance, and to provide real-time feedback compensation for the control amount according to the observed value of the total disturbance; The nonlinear error feedback controller is used to track the signal from the outer loop; Wherein, the outer loop controller comprises: an error feedback controller and an extended state observer for tracking the target speed, and the output value of the outer loop controller is the input target value of the inner loop anti-disturbance controller; The feedforward controller is obtained by constructing a dynamic model of the speed of a diesel engine for power generation; The nonlinear error feedback controller is constructed by the following formula: u=(a1fal(ξ,0.5,δ1)-f0-z2) / b0; The error value is ξ=ν-z1, where ν is the acceleration value transferred by the outer loop, z1 is the observed value of the acceleration by the extended state observer, a1 represents the gain of the nonlinear controller, and z2 / b0 is the compensation amount of f; The speed dynamic model of the diesel engine for power generation is composed of an indicated torque model, a friction torque model, a pump torque model and a load torque model; The dynamic model of the speed of the diesel engine for power generation is expressed as: Where W is the speed, M is i is the indicative torque model, M Fri is the friction torque model, M p is the pump torque model, M load The load torque model is substituted into the indicated torque model, friction torque model, pump torque model and load torque model into the speed dynamic model of the diesel engine for power generation, and the following expression is obtained: Among them, H HLV is the lower calorific value, η i To indicate thermal efficiency, C i is the self-learning parameter, i=1,2,……,5,T oil is the oil temperature; mf is the engine fuel mass flow rate, n cy1 is the number of strokes; And the expression is sorted out to get: After arranging the expression, design the extended state observer; Where a0, b0, f0 are obtained according to the above expression, f is the unknown expression; u is the control quantity; Assume f is continuously differentiable and bounded; ω is the differential of f, and the extended state observer is designed for the system: Where z1 and z2 observe W and f respectively, e1 = z1-W, β1 and β2 represent the time-invariant parameters of two adjustable observers, δ1 is a given parameter; e(t) is the error value; Rewrite the model as: Among them, a0, b1, f0 can be obtained by transforming the formula; Define e3=z3-x1 and design the extended state observer as z3=z4-β1e3+f+b1u; z4=-β2fal(e3,0.5,δ2); Where z3, z4 are the observed values ​​of states x1, x2, and δ2 is the given parameter.

2. The system according to claim 1, characterized in that The error feedback controller is constructed in the following way: Let the error signal be ε=ρ-z3, where ρ is the target speed and z3 is the angle observation value of the extended state observer. The nonlinear error feedback controller is constructed as: ν=(a2fal(ε,0.5,δ3)-f-z4) / b1, where a2 is the gain of the nonlinear controller and z4 / b1 is the compensation amount of f.

3. A diesel engine equipped with the diesel engine speed cascade active disturbance rejection control system as claimed in any one of claims 1 to 2.

4. A locomotive equipped with the diesel engine according to claim 3.

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