A control method and device for smooth multi-mode switching of a power unit

Abstract

The present invention provides a control method and device for smooth multi-mode switching of a power plant, belonging to the technical field of power plants. The method comprises: receiving a combustion mode switching instruction, reading an input signal when operating in a first combustion mode, and respectively determining the fuel injection modes of the first and second combustion modes; calculating a corrected fuel quantity when switching from the first combustion mode to the second combustion mode based on the equivalent energy principle; a controller calculating an initial fuel requirement to maintain the current target speed based on a closed-loop speed deviation, and executing a control law when controlling fuel injection; calculating the speed fluctuation rate of the system under the influence of the initial fuel requirement; comparing multiple sets of different initial fuel requirement values ​​and the corresponding speed fluctuation rate results, and selecting the optimal control law to achieve switching control. The present invention adopts the concept of fuel requirement correction compensation to reduce speed fluctuation and fluctuation duration during the switching process, making the operation easy to implement while achieving good control effect.

Description

Technical Field

[0001] The present invention relates to the field of power plant control, and in particular to a control method and device for smooth multi-mode switching of a power plant. Background Art

[0002] In the pursuit of energy conservation and emission reduction, the combustion mode of power plants is also undergoing changes. Advanced combustion mode technology originated with homogeneous charge compression ignition (HCCI). This combustion mode combines the characteristics of traditional SI and CI, namely homogeneous rapid combustion and low-temperature combustion. It can simultaneously reduce NOx and PM emissions, overcoming the trade-off between the two, and has great potential for energy conservation and emission reduction. However, due to the HCCI combustion mode's misfire phenomenon under low-load conditions, high combustion noise, and worsening PM emissions under medium and high load conditions, HCCI combustion is limited to the limited operating conditions of low and medium loads. Furthermore, a completely homogeneous mixture is difficult to form in the cylinder. In order to improve the problem of limited HCCI operating conditions, attempts have been made to use different means to control its combustion process and expand its operating conditions. As a result, a series of advanced combustion modes with their own characteristics have been derived, such as premixed charge compression ignition (PPCI) and reaction controlled compression ignition (RCCI). Their premixed gas preparation methods and fuel use are different.

[0003] Using a single combustion mode cannot guarantee that the power unit's performance remains optimal under all operating conditions. Similarly, using a single fuel cannot achieve optimal performance under all operating conditions. To address the limited operating range under a single operating mode, a multi-mode combustion approach has been proposed, using different combinations of combustion modes to expand the load boundary and achieve optimal operation of the power unit over the full operating range. However, multi-mode combustion inevitably faces the problem of mode switching. Due to the inherent differences in fuel type and combustion mechanism, the switching process directly leads to step changes in control parameters and changes in combustion reaction conditions during the combustion mode switching process. This results in an uneven combustion mode switching process, fluctuations in parameters such as speed, combustion center of gravity, and IMEP, and even misfires and switching failures, which in turn lead to worsening emissions. Summary of the Invention

[0004] The present invention provides a control method and device for smooth multi-mode switching of a power device, which are used to solve the performance fluctuation problem commonly existing in the multi-mode switching process of the power device.

[0005] In the first aspect, the present invention provides a control method for smooth switching of multiple modes of a power plant, which aims to correct and compensate for the performance fluctuation problem caused by controller delay in the control system during the switching of combustion modes of a dual-fuel power plant, and includes: receiving a combustion mode switching instruction, reading the input signal when operating in the first combustion mode, and confirming the fuel injection mode of the first combustion mode and the second combustion mode respectively; the controller calculates the initial fuel requirement u0 for maintaining the current target speed based on the closed-loop speed deviation, and calculates the corrected fuel amount u when switching from the first combustion mode to the second combustion mode based on the equivalent energy principle; executes the control law when controlling fuel injection, and calculates the speed fluctuation rate of the system; wherein the control law is u=k·u0, k is the correction coefficient; compares multiple groups of different corrected fuel amount values ​​and corresponding speed fluctuation rate results, and selects the optimal control law to achieve switching control.

[0006] In a second aspect, the present invention further provides a control device for smooth multi-mode switching of a power plant, comprising:

[0007] a first processing module, configured to receive a combustion mode switching instruction, read an input signal when operating in the first combustion mode, and respectively determine a fuel injection mode for the first combustion mode and a second combustion mode;

[0008] a second processing module for calculating a corrected fuel quantity when switching from the first combustion mode to the second combustion mode based on the equivalent energy principle; a controller for calculating an initial fuel requirement to maintain the current target speed based on the closed-loop speed deviation; and executing a control law when controlling fuel injection; wherein the control law is u=k·u0, where u is the corrected fuel quantity, u0 is the initial fuel requirement, and k is a correction coefficient;

[0009] The third processing module is used to calculate the speed fluctuation rate of the system under the action of the initial fuel demand;

[0010] The fourth processing module is used to compare multiple groups of different initial fuel demand values ​​and corresponding speed fluctuation results, and select the optimal control law to achieve switching control.

[0011] In a third aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the control method for smooth multi-mode switching of a power unit as described above are implemented.

[0012] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the control method for smooth multi-mode switching of a power device as described in any one of the above.

[0013] The control method and device for smooth switching of multiple modes of a power plant provided by the present invention address the defect that the use of a single PID controller cannot meet the smoothness requirements during the multi-mode switching process. Therefore, the idea of ​​fuel demand correction compensation is adopted. At the instant of combustion mode switching, the effective thermal efficiency at the next moment obtained by feedback is involved in the online calculation and correction of the fuel demand of the cycle, thereby reducing the speed fluctuation and fluctuation duration during the switching process, making the operation easy to implement and achieving good control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 It is a flow chart of a control method for smooth multi-mode switching of a power plant provided by the present invention;

[0016] Figure 2 1 is a schematic structural diagram of a dual-fuel power plant provided by the present invention that can be used in this method;

[0017] Figure 3 This is a block diagram of the input / output speed closed-loop control system of the dual-fuel power plant provided by the present invention;

[0018] Figure 4 It is a structural schematic diagram of the electronic device provided by the present invention;

[0019] Wherein, the accompanying drawings are marked as follows:

[0020] 1: Internal combustion engine cylinder; 2: Fuel tank; 3: Fuel consumption meter; 4: Fuel filter; 5: High-pressure fuel pump; 6: High-pressure fuel rail; 7: Combustion analyzer; 8: Methanol rail; 9: Methanol storage tank; 10: Emission analyzer; 11: Engine turbocharger; 12: First fuel supply system; 13: Second fuel supply system. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some 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 technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0022] It should be noted that, in the description of the embodiments of the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "include a ..." do not exclude the presence of other identical elements in the process, method, article or device comprising the elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0023] The terms "first," "second," and the like in this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that such terms are interchangeable where appropriate, so that embodiments of this application can be implemented in an order other than that illustrated or described herein. Furthermore, the terms "first," "second," and the like generally distinguish objects of a class and do not limit the number of objects; for example, the first object can be one or more. Furthermore, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates an "or" relationship between the connected objects.

[0024] At present, the switching of combustion modes between traditional combustion and low-temperature combustion is a unique and inevitable problem of diesel power plants. When the power plant is running, it is necessary to change the corresponding load when responding to different working conditions, because it is inevitable to switch between modes. The quality of combustion mode switching control is directly reflected in the quality of the transient performance of the power plant. Matching suitable combustion modes for different working conditions to ensure that the power plant can operate stably within the full working range while achieving smooth switching of combustion modes, establishing an input / output control system, and using a PID controller to calculate the fuel demand of the power plant to maintain the current target speed based on the closed-loop speed deviation. On this basis, a fuel demand correction model is established based on the principle of equivalent work to achieve more accurate calculation of the fuel amount during the switching process and make up for the shortcoming of the PID controller's response delay. The fuel amount correction model quantifies the calculation process of the fuel amount with a mathematical expression, which is a key step in achieving stable control of the switching process, which is also the content to be protected by the present invention.

[0025] In order to achieve the above object, the present invention provides the following technical solutions:

[0026] (1) First, based on the control objectives of the power unit, determine the controller and input / output signals, and establish an input / output control system.

[0027] The output signals of the established input / output control system are the actual speed and speed fluctuation rate of the controlled object. The input signals are the target speed, the fuel's lower heating value, the switching enable signal, and the effective thermal efficiency. The control target is the current operating condition of the system. When the combustion mode needs to be switched, the system output is required to quickly and smoothly track the target speed.

[0028] (2) Secondly, for the combustion mode selected for each operating condition of the dual-fuel power unit, the controller calculates the initial fuel requirement to maintain the current target speed based on the closed-loop speed deviation.

[0029] Specifically, the PID controller calculates the difference between the actual speed and the target speed to obtain the initial fuel demand for the next cycle (i.e., the fuel injection amount in the new mode after the fuel mode is switched), and repeats the calculation to maintain stable system operation.

[0030] (3) Finally, based on the crankshaft dynamics principle, a fuel demand correction model is established using the input signal and the output feedback signal. The initial fuel quantity calculated by the PID controller is corrected online in real time, and the correction value is input into the controlled object to achieve smooth control of the switching process.

[0031] Based on the principle of crankshaft dynamics, a fuel demand correction model is built, and the effective work equation before and after the combustion mode switching is established. The fuel calorific value, the effective thermal efficiency of the switching process, and the fuel demand are substituted into the equation to calculate the corrected fuel demand.

[0032] Based on the content of the above embodiment, as an optional embodiment, Figure 1 FIG. 1 is a flow chart of a control method for smooth multi-mode switching of a power plant provided by the present invention. Figure 1 In order to solve the performance fluctuation problem caused by controller delay in the control system during the switching process of the dual-fuel power plant combustion mode, the fuel amount during the switching process is corrected and compensated. The method includes but is not limited to the following steps:

[0033] Step 101: receiving a combustion mode switching instruction, reading an input signal when operating in a first combustion mode, and confirming fuel injection modes of the first combustion mode and the second combustion mode respectively.

[0034] The system operates stably in the first combustion mode under the action of the closed-loop controller. At a certain time T, the system receives a combustion mode switching instruction, and the system controller begins to intervene.

[0035] After receiving the switch command, the algorithm activates and begins reading the input signal when the system is operating in the first combustion mode, determining the fuel injection mode for the first and second combustion modes. The fuel injection mode refers to the number of fuel injections or the fuel injection method, such as single injection of pure fuel, multiple injections, or dual fuel injection.

[0036] Among them, the input signals include parameters such as power unit speed, fuel quantity, fuel injection timing, rail pressure, and combustion thermal efficiency.

[0037] Step 102: Calculate the corrected fuel amount when switching from the first combustion mode to the second combustion mode based on the equivalent energy principle, calculate the initial fuel requirement for maintaining the current target speed based on the closed-loop speed deviation, load the initial fuel requirement to the controller, and execute the control law when controlling fuel injection; wherein the control law is u = k·u0, where u is the corrected fuel amount, u0 is the initial fuel requirement, and k is the correction coefficient.

[0038] The control rate begins to execute after the system receives the mode switching instruction, and the controlled state variable is adjusted in time according to the system input signal. The specific adjustment method refers to correcting the initial value u0 of the fuel amount in the switching process, obtaining the correction coefficient k, and executing the correction value u, wherein the fuel correction refers to correcting the injection amount of the first fuel in the switching process.

[0039] Specifically, the PID controller calculates the difference between the actual speed feedback and the target speed to obtain the initial fuel demand u0. The PID controller continuously updates the initial fuel demand u0 to adapt to new operating conditions in each cycle and maintain stable system operation.

[0040] Specifically, based on the crankshaft dynamics principle, a mathematical equation for the effective work before and after switching is established, which is expressed as follows:

[0041]

[0042]

[0043] in, Refers to the effective power output of the crankshaft per unit working cycle in the first combustion mode before mode switching. Refers to the effective work output of the crankshaft per unit working cycle in the second combustion mode after mode switching; Refers to the effective thermal efficiency within several working cycles before the first combustion mode is switched. Refers to the effective thermal efficiency within several working cycles after switching to the second combustion mode; B ij Refers to the injection quantity of the jth type of fuel per unit working cycle in the i-th combustion mode; Refers to the first fuel calorific value, Refers to the calorific value of the second fuel; under stable operating conditions, the system switches the combustion mode. The load does not change during the switching process. The external load M e is a constant, and the crankshaft output effective work is equal before and after switching:

[0044]

[0045] Based on the assumption that the crankshaft output effective work is equal before and after switching, the correction coefficient is obtained:

[0046]

[0047] in,

[0048] B 21 =kB 11 ;

[0049] The expression of the correction coefficient k is:

[0050]

[0051] Step 103: Calculate the speed fluctuation rate of the system under the effect of the initial fuel demand.

[0052] The system speed fluctuation rate is used to characterize the instantaneous overshoot degree of the power unit speed during the switching process of the combustion mode. The speed fluctuation rate is an evaluation index used to measure the quality of the control system. The calculation method is as follows:

[0053]

[0054] Where n1 refers to the speed in the first combustion mode before mode switching, n2 refers to the speed in the second combustion mode after mode switching, Φ n (k) represents the speed fluctuation rate after switching, Φ n (k-1) represents the rotation speed fluctuation rate before switching.

[0055] The speed is calculated as follows:

[0056] According to the speed characteristics and speed regulation characteristics of the power unit measured in the test, the following expressions can be obtained:

[0057]

[0058] P e Indicates power.

[0059] Where B(t) refers to the fuel injection volume per hour, and the following expression for the rotational speed is obtained:

[0060]

[0061] Then we can get:

[0062]

[0063]

[0064] Step 104: Compare multiple groups of different initial fuel demand values ​​and corresponding speed fluctuation results, and select the optimal control law to achieve switching control.

[0065] In order to explain the present invention more clearly, further description will be given below in conjunction with another embodiment. In this embodiment, the power unit is a diesel-methanol power unit.

[0066] refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of a dual-fuel power plant that can be used in this method provided by the present invention, such as Figure 2 As shown, the device includes: an internal combustion engine cylinder 1, a combustion analyzer 7, an emission analyzer 10, a power unit turbocharger 11, a first fuel supply system 12, and a second fuel supply system 13; wherein, the first fuel supply system 12 includes a fuel tank 2, a fuel consumption meter 3, a fuel filter 4, a high-pressure fuel pump 5, and a high-pressure fuel rail 6; the second fuel supply system 13 includes an alcohol rail 8 and a methanol storage tank 9.

[0067] The above-mentioned dual-fuel power unit can selectively operate under the first fuel supply and the second fuel supply. Within the propulsion characteristics of the ship's main engine, different injection times and injection fuel amounts can be configured for diesel fuel and methanol fuel through the action of the controller, providing conditions for the formation of various combustion modes.

[0068] In this embodiment, the first fuel is high calorific value fuel diesel, the second fuel is low calorific value fuel natural gas, and multiple combustion modes are adopted, among which the first combustion mode refers to the CI combustion mode of single diesel injection, the second combustion mode refers to the PCCI combustion mode of multiple diesel injections, and the third combustion mode refers to the RCCI combustion mode of mixed injection of diesel and methanol.

[0069] The specific implementation steps of the control method for achieving smooth multi-mode switching of a power plant using the above-mentioned dual-fuel power plant structure and using both diesel and natural gas fuels are as follows:

[0070] first, Figure 3 This is a block diagram of the input / output speed closed-loop control system of the dual-fuel power plant provided by the present invention, refer to Figure 3For the multi-mode smooth switching control of a dual-fuel power plant, the input signal, output signal, and control target of the control system are determined, and an input / output control system for the dual-fuel power plant is established. In this embodiment, the output speed and the speed fluctuation rate obtained by further calculation are used as the output of the controlled object, and the corrected fuel demand is used as the input of the controlled object.

[0071] Secondly, reference Figure 3 More specifically, the output of the controlled object is the measured speed, and the input signal is the corrected fuel demand. After receiving the external combustion mode switching enable signal, the control system determines the current state of the power unit and performs basic fuel quantity management calculations for the power unit. When all switching conditions are met, the system switching function is activated, and the power unit switches from CI combustion mode to PCCI combustion mode.

[0072] The specific logic is as follows: the injection mode selection module determines to enter the pilot injection enabling action execution module, and the pilot injection base oil quantity is checked in the MAP chart according to the power unit speed and the cycle injection quantity. If the pilot injection quantity is greater than the maximum limit value, the maximum limit value of the pilot injection quantity is output; if the pilot injection quantity is less than the minimum limit value of the pilot injection, the pilot injection parameter outputs the minimum value; if the pilot injection quantity is less than the maximum limit value but greater than the minimum limit value, the pilot injection quantity look-up table value is output, and the pilot injection quantity is subtracted from the main injection quantity. If the oil quantity is less than the minimum injection quantity limit, the pilot injection action is canceled.

[0073] Furthermore, when the pilot injection action is executed normally, the system enters the mode switching state. At this time, the PID controller can no longer meet the requirements of instantaneous overshoot correction, and the fuel correction module begins to intervene. The specific correction calculation formula is:

[0074]

[0075] Where B1 is the fuel demand of the first fuel mode, is the fuel requirement for the qth injection in the second fuel mode.

[0076] The relationship between the corrected fuel quantity during the switching process and the required fuel quantity under stable operation of the CI combustion mode is further obtained:

[0077]

[0078] in, Refers to the effective thermal efficiency within several working cycles before the first combustion mode is switched. Refers to the effective thermal efficiency within several working cycles after switching to the second combustion mode;

[0079] Finally, the speed fluctuation rate is obtained, and its specific expression is:

[0080]

[0081] in, is the equivalent diesel quantity in the first fuel injection mode. is the deviation between the speed after switching and the target value, It is the deviation between the speed before switching and the target value.

[0082] Then, when the system successfully completes the switch to enter the PCCI combustion mode, it will run stably for a period of time and then change the system switch enable again. Methanol fuel will start to be supplied into the cylinder and the power unit will start to enter the combustion mode switch state. Before the combustion mode is switched, the methanol amount of the power unit is calculated and the combustion mode switching process is judged. The specific logic is: when the combustion mode is switched from PCCI to RCCI, the switching process is judged based on the total fuel amount obtained by the diesel fuel amount PID calculation module. When the diesel injection amount is less than or equal to 20mg, the power unit is in the fuel conversion process. During the conversion process, the methanol injection amount B is increased at a rate of 0.01mg per step. met , when the diesel injection amount is less than or equal to 20mg, the combustion mode is switched successfully;

[0083] Furthermore, when the switching process begins, the fuel correction module begins to intervene, and its specific correction calculation formula is:

[0084]

[0085] The relationship between the corrected fuel quantity during the switching process and the required fuel quantity under the stable operation condition of the PCCI combustion mode is further obtained:

[0086]

[0087] Finally, the speed fluctuation rate is obtained, and its specific expression is:

[0088]

[0089] in, is the diesel injection amount in the first and second fuel injection modes, B met is the methanol fuel injection amount, is the deviation between the speed after switching and the target value, It is the deviation between the speed before switching and the target value.

[0090] Furthermore, when entering the RCCI combustion mode, the fuel quantity calculated by the dual-fuel mode PID controller and the power unit speed are looked up in the table to obtain the power unit pilot oil quantity, and the power unit fuel quantity is limited through comparison to maintain stable system operation.

[0091] On the other hand, the present invention also provides a control device for smooth multi-mode switching of a power plant, comprising:

[0092] a first processing module, configured to receive a combustion mode switching instruction, read an input signal when operating in the first combustion mode, and respectively determine a fuel injection mode for the first combustion mode and a second combustion mode;

[0093] a second processing module for calculating a corrected fuel quantity when switching from the first combustion mode to the second combustion mode based on the equivalent energy principle; a controller for calculating an initial fuel requirement to maintain the current target speed based on the closed-loop speed deviation; and executing a control law when controlling fuel injection; wherein the control law is u=k·u0, where u is the corrected fuel quantity, u0 is the initial fuel requirement, and k is a correction coefficient;

[0094] The third processing module is used to calculate the speed fluctuation rate of the system under the action of the initial fuel demand;

[0095] The fourth processing module is used to compare multiple groups of different initial fuel demand values ​​and corresponding speed fluctuation results, and select the optimal control law to achieve switching control.

[0096] It should be noted that the control device for smooth multi-mode switching of a power plant provided in an embodiment of the present invention can, during specific operation, execute the control method for smooth multi-mode switching of a power plant described in any of the above embodiments, which will not be elaborated in this embodiment.

[0097] Figure 4 Schematic diagram of the structure of the electronic device provided by the present invention, such as Figure 4 As shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430, and a communication bus 440, wherein the processor 410, the communication interface 420, and the memory 430 communicate with each other via the communication bus 440. The processor 410 may call the logic instructions in the memory 430 to execute the control method for smooth multi-mode switching of the power unit.

[0098] In addition, the logic instructions in the above-mentioned memory 430 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0099] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the control method for smooth multi-mode switching of a power device provided in the above embodiments.

[0100] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A control method for smooth multi-mode switching of a power plant, characterized in that: Combustion mode switching for dual-fuel power plants, including: receiving a combustion mode switching instruction, reading an input signal when operating in a first combustion mode, and confirming fuel injection modes for the first combustion mode and a second combustion mode respectively; The corrected fuel amount when switching from the first combustion mode to the second combustion mode is calculated based on the equivalent energy principle, and the initial fuel requirement to maintain the current target speed is calculated based on the closed-loop speed deviation. The controller loads the initial fuel requirement and executes the control law when controlling fuel injection; wherein the control law is u=k·u0, where u is the corrected fuel amount, u0 is the initial fuel requirement, and k is the correction coefficient; Calculate the system speed fluctuation rate under the action of initial fuel demand; By comparing multiple groups of different initial fuel demand values ​​and the corresponding speed fluctuation results, the optimal control law is selected to achieve switching control.

2. The control method for smooth multi-mode switching of a power plant according to claim 1, characterized in that: Calculating the corrected fuel amount when switching from the first combustion mode to the second combustion mode according to the equivalent energy principle includes: Based on the crankshaft dynamics principle, the mathematical equation for the effective work before and after switching is established: in, Refers to the effective power output of the crankshaft per unit working cycle in the first combustion mode before mode switching. Refers to the effective work output of the crankshaft per unit working cycle in the second combustion mode after mode switching; Refers to the effective thermal efficiency within several working cycles before the first combustion mode is switched. Refers to the effective thermal efficiency within several working cycles after switching to the second combustion mode; B ij Refers to the injection quantity of the jth type of fuel per unit working cycle in the i-th combustion mode; Refers to the first fuel calorific value, Refers to the calorific value of the second fuel; Based on the principle that the effective work output by the crankshaft is equal before and after the switching, the correction coefficient is obtained and the corrected fuel amount is calculated.

3. The control method for smooth multi-mode switching of a power plant according to claim 2, characterized in that: Based on the principle that the effective work output by the crankshaft is equal before and after switching, the correction coefficient is obtained, including: make have to: in, B 21 =kB 11 ; The expression of the correction coefficient k is:

4. The control method for smooth multi-mode switching of a power plant according to claim 2, characterized in that: The calculation method of the speed fluctuation rate is as follows: Where n1 refers to the speed in the first combustion mode before mode switching, n2 refers to the speed in the second combustion mode after mode switching, Φ n (m) represents the speed fluctuation rate after switching, Φ n (m-1) represents the rotation speed fluctuation rate before switching.

5. The control method for smooth multi-mode switching of a power plant according to claim 4, characterized in that: The formula for calculating the rotational speed is: Among them, M e represents the external load, and B(t) is the fuel injection amount per unit hour.

6. The control method for smooth multi-mode switching of a power plant according to claim 1, characterized in that: After receiving the combustion mode switching instruction, the control law is executed to correct the initial fuel demand u0 of the switching process, obtain the correction coefficient k, and execute the correction value u.

7. The control method for smooth multi-mode switching of a power plant according to claim 1, characterized in that: The power unit is a diesel-methanol power unit.

8. A control device for smooth multi-mode switching of a power plant, characterized in that: include: a first processing module, configured to receive a combustion mode switching instruction, read an input signal when operating in the first combustion mode, and respectively determine a fuel injection mode for the first combustion mode and a second combustion mode; a second processing module for calculating a corrected fuel quantity when switching from the first combustion mode to the second combustion mode based on the equivalent energy principle, and calculating an initial fuel requirement to maintain the current target speed based on the closed-loop speed deviation; a controller loading the initial fuel requirement and executing a control law when controlling fuel injection; wherein the control law is u=k·u0, where u is the corrected fuel quantity, u0 is the initial fuel requirement, and k is a correction coefficient; The third processing module is used to calculate the speed fluctuation rate of the system under the action of the initial fuel demand; The fourth processing module is used to compare multiple groups of different initial fuel demand values ​​and corresponding speed fluctuation results, and select the optimal control law to achieve switching control.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the control method for smooth multi-mode switching of a power plant as described in any one of claims 1 to 7 are implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the control method for smooth multi-mode switching of a power plant as claimed in any one of claims 1 to 7 are implemented.

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