Method for determining simulation parameters of electrolytic aluminum electrolysis cell

Abstract

The present invention relates to the technical field of power system simulation analysis. Disclosed is a method for determining simulation parameters of an electrolytic aluminum electrolysis cell, comprising: applying disturbance to an electrolytic current of an electrolysis cell, recording voltage and current data of the electrolysis cell, and carrying out per-unit processing; establishing a second-order system on the basis of a dynamic process of the electrolysis cell; and substituting voltage and current disturbance change data into the second-order system to determine simulation parameters of the electrolysis cell. According to the present invention, the dynamic process of the electrolysis cell is regarded as a second-order system response, which greatly improves the simulation precision compared with the current mode of only using a voltage source and a resistor connected in series, and has a positive effect on improving accurate simulation of an electrolytic aluminum load.

Description

A method for determining simulation parameters of aluminum electrolytic cell Technical Field

[0001] The present invention relates to the technical field of power system simulation analysis, and in particular to a method for determining simulation parameters of an electrolytic aluminum cell. Background Art

[0002] The power system is a complex system, and its research often relies on computational simulation. Computer simulation of a power system requires building models of various components and determining relevant parameters. The power load is a crucial component of the power system, and establishing accurate load models is a crucial foundation for power system simulation. Electrolytic aluminum is a high-energy load, with its share of electricity consumption exceeding 20% ​​in some regions. Accurate simulation and analysis of these regional power grids requires accurate modeling of the electrolytic aluminum load.

[0003] The electrolytic cell is the primary power consumer in the aluminum electrolysis load, typically consuming over 90% of the plant's total power consumption. Accurate simulation of the cell is crucial for aluminum electrolysis load simulation. Currently, electrolytic cells are typically simulated using a voltage source in series with a resistor. However, compared to actual data, existing simulation methods fail to accurately reflect the cell's response characteristics. Therefore, this patent proposes a new electrolytic cell simulation method.

[0004] Summary of the Invention

[0005] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0006] In view of the above existing problems, the present invention is proposed.

[0007] Therefore, the technical problem solved by the present invention is that the existing technology cannot accurately reflect the response characteristics of the electrolytic cell.

[0008] To solve the above technical problems, the present invention provides the following technical solutions: a method for determining simulation parameters of an electrolytic aluminum reduction cell, comprising:

[0009] Apply disturbance to the electrolytic current of the electrolytic cell, record the voltage and current data of the electrolytic cell, and perform normalization processing;

[0010] Establish a second-order system based on the dynamic process of the electrolytic cell;

[0011] The voltage and current disturbance change data are brought into the second-order system to determine the electrolytic cell simulation parameters.

[0012] As a preferred embodiment of the method for determining simulation parameters of an electrolytic aluminum cell according to the present invention, the electrolytic cell comprises:

[0013] Through the first resistor R AL1 , the second resistor R AL2 and the first inductor L Al1 , the second inductor L Al2 The series branches are connected in parallel and then connected to the voltage source E Al The electrolytic cells are simulated in series.

[0014] As a preferred solution of the method for determining the simulation parameters of the electrolytic aluminum electrolytic cell of the present invention, wherein: the voltage data during the disturbance is defined as U dc,m , current data is I dc,m .

[0015] As a preferred solution of the method for determining the simulation parameters of the aluminum electrolytic cell of the present invention, the normalized data is expressed as:

[0016] Among them, U N , I N They are the rated working voltage and rated working current of the electrolytic cell respectively.

[0017] As a preferred solution of the method for determining the simulation parameters of the aluminum electrolytic cell of the present invention, wherein: U dc,p , I dc,p The value of the disturbance at the moment before is denoted as U dc,0 , I dc,0 ;

[0018] Take U dc,p , I dc,p The data after the disturbance moment are respectively recorded as U dc,f , I dc,f .

[0019] As a preferred solution of the method for determining the simulation parameters of the aluminum electrolytic cell of the present invention, the disturbance change data is expressed as: ΔU dc =U dc,f -U dc,0 ΔI dc =I dc,f -I dc,0

[0020] As a preferred solution of the method for determining the simulation parameters of the aluminum electrolytic cell according to the present invention, the second-order system is expressed as:

[0021] Among them, K1, K2, T1, and T2 are system parameters.

[0022] As a preferred solution of the method for determining the simulation parameters of the aluminum electrolytic cell of the present invention, wherein: ΔU dc As the input X of the second-order system, with ΔI dc As the output Y of the second-order system, the nonlinear square function is used to identify the parameters K1, K2, T1, and T2 with minimum square error to obtain their corresponding values.

[0023] As a preferred solution of the method for determining the simulation parameters of the aluminum electrolytic cell of the present invention, the per-unit values ​​of the parameters of the electrolytic cell are expressed as:

[0024] As a preferred solution of the method for determining the simulation parameters of the electrolytic aluminum electrolytic cell of the present invention, wherein: the per-unit values ​​of the parameters of the electrolytic cell are converted into nominal values, and R Al1 Z N 、R Al2 Z N , L Al1 Z N , L Al2 Z N 、E Al U N ,in

[0025] Based on the connection relationship of the electrolytic cell components, the nominal values ​​are imported into the simulation software to simulate the dynamic characteristics of the electrolytic cell.

[0026] Beneficial effects of the present invention: The method for determining the simulation parameters of an electrolytic aluminum cell provided by the present invention regards the dynamic process of the electrolytic cell as a second-order system response, which greatly improves the simulation accuracy compared with the current method of only using a voltage source and a resistor in series, and has a positive effect on improving the accurate simulation of the electrolytic aluminum load. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing 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 effort. Among them:

[0028] FIG1 is a flow chart of an electrolytic cell simulation method for determining simulation parameters of an electrolytic aluminum cell according to an embodiment of the present invention;

[0029] FIG2 is a circuit diagram of an electrolytic cell simulation for a method for determining simulation parameters of an aluminum electrolytic cell according to an embodiment of the present invention;

[0030] FIG3 is a diagram of the measured voltage of an electrolytic cell according to a method for determining simulation parameters of an electrolytic aluminum cell according to an embodiment of the present invention;

[0031] FIG4 is a diagram of the actual current measured in an electrolytic cell according to a method for determining simulation parameters of an electrolytic aluminum cell according to an embodiment of the present invention;

[0032] FIG5 is a comparison diagram of the measured and simulated electrolytic cell currents of the method for determining simulation parameters of an electrolytic aluminum electrolytic cell according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0036] The present invention is described in detail with reference to schematic diagrams. For ease of illustration, cross-sectional views of device structures may be partially enlarged and not to scale when describing embodiments of the present invention. Furthermore, the schematic diagrams are merely illustrative and should not limit the scope of the present invention. Furthermore, in actual production, the three-dimensional dimensions of length, width, and depth should be included.

[0037] In the description of the present invention, it should be noted that the terms "upper, lower, inner, and outer" and other references to orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first, second, or third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In this disclosure, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they may refer to fixed, removable, or integral connections. They may also refer to mechanical, electrical, or direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure.

[0039] Example 1

[0040] 1-2 , which are a first embodiment of the present invention, provide a method for determining simulation parameters of an electrolytic aluminum reduction cell, including:

[0041] S1: Apply disturbance to the electrolytic current of the electrolytic cell, record the voltage and current data of the electrolytic cell, and perform normalization processing;

[0042] Furthermore, the electrolytic cell includes a first resistor R AL1 , the second resistor R AL2 and the first inductor L Al1 , the second inductor L Al2 The series branches are connected in parallel and then connected to the voltage source E Al The electrolytic cells are simulated in series.

[0043] Furthermore, the voltage data during disturbance is defined as U dc,m , current data is I dc,m .

[0044] The normalized data is expressed as:

[0045] Among them, U N , I N They are the rated working voltage and rated working current of the electrolytic cell respectively.

[0046] Take U dc,p , I dc,p The value of the disturbance at the moment before is denoted as U dc,0 , I dc,0 ;

[0047] Take U dc,p , I dc,p The data after the disturbance moment are respectively recorded as U dc,f , I dc,f .

[0048] The disturbance change data is expressed as: ΔU dc =U dc,f -U dc,0 ΔI dc =I dc,f -I dc,0

[0049] S2: Establish a second-order system based on the dynamic process of the electrolytic cell;

[0050] Furthermore, the second-order system is expressed as:

[0051] Among them, K1, K2, T1, and T2 are system parameters.

[0052] S3: Bring the voltage and current disturbance change data into the second-order system to determine the electrolytic cell simulation parameters.

[0053] Furthermore, ΔU dc As the input X of the second-order system, with ΔI dc As the output Y of the second-order system, the nonlinear square function is used to identify the parameters K1, K2, T1, and T2 with minimum square error to obtain their corresponding values.

[0054] Furthermore, the per-unit values ​​of the electrolytic cell parameters are expressed as:

[0055] Furthermore, the per-unit values ​​of the electrolytic cell parameters are converted into nominal values ​​to obtain R Al1 Z N 、R Al2 Z N , L Al1 Z N , L Al2 Z N 、E Al U N ,in

[0056] Based on the connection relationship of the electrolytic cell components, the nominal values ​​are imported into the simulation software to simulate the dynamic characteristics of the electrolytic cell.

[0057] Example 2

[0058] 3-5 , which illustrate an embodiment of the present invention, a method for determining simulation parameters of an aluminum electrolytic cell is provided. To demonstrate the beneficial effects of the present invention, specific test data are used for scientific demonstration.

[0059] In this embodiment, the rated voltage of the electrolytic cell of the electrolytic aluminum plant is U N 1297V, rated current I N By adjusting the electrolytic aluminum control system, the electrolytic cell current increased from 479kA to 489kA; the recorded electrolytic cell voltage and current change data are shown in Figures 3 and 4, and are respectively recorded as U dc,m , I dc,m The sampling interval is 1ms.

[0060] In Figures 3 and 4, the disturbance is applied at 2 seconds, and the U dc,p , I dc,p Value U dc,0 =0.9037, I dc,0 =0.9585. Take U dc,p , I dc,p The data after 2S are respectively counted as U dc,f , I dc,f , whose values ​​are respectively dc,0 , I dc,0 Make the difference to form the disturbance change data ΔU dc , ΔI dc .

[0061] ΔU dc As the input of the second-order system, ΔI dc As the output of the second-order system. In Matlab, use lsqnonlin to identify the parameters K1, K2, T1, and T2 with minimum variance. The lsqnonlin function requires the error function and the initial values ​​of the parameters K1, T1, K2, and T2 (corresponding to Prms(1), Prms(2), Prms(3), and Prms(4), respectively). The initial values ​​of K1, K2, T1, and T2 are all set to 1. The error function can be written as:

[0062] function[Error]=calculate_error(Prms)

[0063] sys_1=tf([Prms(1)*Prms(4)+Prms(3)*Prms(2)

[0064] Prms(1)+Prms(3)],[Prms(2)*Prms(4)Prms(2)+Prms(4)1]);

[0065] out_y=lsim(sys_1,dUdc,t_in);

[0066] Error = out_y - dIdc;

[0067] end

[0068] In the calculate_error function, dUdc corresponds to ΔU dc , dIdc corresponds to ΔI dc .

[0069] After calculation, K1=0.364068, T1=0.237277, K2=1.653980, T2=1.677734. Then the standard values ​​of the parameters of the electrolytic cell are: R Al1 =2.746742, R Al2 =0.604602, L Al1 =0.651738, L Al2 =1.014362, E Al =0.428802. Converted into nominal values, they are: 7.125048Ω, 1.568338Ω, 1.690608H, 2.631254H, 556.155985V.

[0070] Using the aforementioned electrolytic aluminum parameters according to ΔU dc Calculated ΔI dc *Compared to the measured ΔI dc The comparison is shown in Figure 5. As can be seen from Figure 5, the method of this patent can accurately reflect the dynamic characteristics of the electrolytic cell.

[0071] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for determining simulation parameters of an aluminum electrolytic cell, characterized in that: include: Apply disturbance to the electrolytic current of the electrolytic cell, record the voltage and current data of the electrolytic cell, and perform normalization processing; Establish a second-order system based on the dynamic process of the electrolyzer; The voltage and current disturbance change data are brought into the second-order system to determine the electrolytic cell simulation parameters.

2. The method for determining simulation parameters of an aluminum electrolytic cell according to claim 1, characterized in that: The electrolytic cell comprises: Through the first resistor R AL1 , the second resistor R AL2 and the first inductor L Al1 , the second inductor L Al2 The series branches are connected in parallel and then connected to the voltage source E Al The electrolytic cells are simulated in series.

3. The method for determining simulation parameters of an aluminum electrolytic cell according to claim 2, characterized in that: Define the voltage data during disturbance as U dc,m , current data is I dc,m .

4. The method for determining simulation parameters of an aluminum electrolytic cell according to claim 3, characterized in that: The normalized data is expressed as: Among them, U N ,I N They are the rated working voltage and rated working current of the electrolytic cell respectively.

5. The method for determining simulation parameters of an aluminum electrolytic cell according to claim 4, characterized in that: Take U dc,p ,I dc,p The value of the disturbance before the moment is denoted as U dc,0 ,I dc,0 ; Take U dc,p ,I dc,p The data after the disturbance moment are respectively recorded as U dc,f ,I dc,f .

6. The method for determining simulation parameters of an aluminum electrolytic cell according to claim 5, characterized in that: The disturbance change data is expressed as: ΔU dc =U dc,f -U dc,0 ΔI dc =I dc,f -I dc,0 7. The method for determining simulation parameters of an aluminum electrolytic cell according to claim 1, characterized in that: The second-order system is expressed as: Among them, K1, K2, T1, and T2 are system parameters.

8. The method for determining simulation parameters of an aluminum electrolytic cell according to claim 7, characterized in that: ΔU dc As the input X of the second-order system, ΔI dc As the output Y of the second-order system, the nonlinear square function is used to identify the parameters K1, K2, T1, and T2 with minimum square error to obtain their corresponding values.

9. The method for determining simulation parameters of an aluminum electrolytic cell according to claim 2 or 8, characterized in that: The per unit values ​​of the electrolytic cell parameters are expressed as:

10. The method for determining simulation parameters of an aluminum electrolytic cell according to claim 9, characterized in that: Convert the per unit values ​​of the electrolytic cell parameters into nominal values ​​to obtain R Al1 Z N , R Al2 Z N , L Al1 Z N , L Al2 Z N 、E Al U N ,in Based on the connection relationship of the electrolytic cell components, the nominal values ​​are imported into the simulation software to simulate the dynamic characteristics of the electrolytic cell.

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