Control method and device for multi-mode smooth switching of power device

Abstract

The invention provides a control method and device for smooth switching of multiple modes of a power plant, and belongs to the technical field of the power plant. The method comprises the steps that a combustion mode switching instruction is received, an input signal during operation in a first combustion mode is read, and fuel injection modes of the first combustion mode and a second combustion mode are confirmed respectively; the corrected fuel quantity when the first combustion mode is switched to the second combustion mode is calculated according to the equivalent energy principle, the controller calculates the initial fuel demand for maintaining the current target rotating speed according to the closed-loop rotating speed deviation, and the control law is executed when fuel injection is controlled; calculating the rotating speed fluctuation ratio of the system under the action of the initial fuel demand quantity; and comparing the multiple groups of different initial fuel demand quantity values and the corresponding rotating speed fluctuation rate results, and selecting an optimal control law to realize switching control. The thought of fuel demand quantity correction compensation is adopted, rotating speed fluctuation and fluctuation duration in the switching process are reduced, operation is easy to achieve, and meanwhile a good control effect is obtained.

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 context of pursuing energy conservation and emission reduction, the combustion mode of power units is also undergoing changes. Advanced combustion mode technology originated from homogeneous charge compression ignition (HCCI), which combines the characteristics of traditional SI and CI, namely homogeneous rapid combustion and low-temperature combustion. It can reduce NOx and PM emissions at the same time, overcome the mutually exclusive relationship (Trade-off) between the two, and has great potential for energy conservation and emission reduction. However, due to the misfire phenomenon of the HCCI combustion mode under low load conditions, high combustion noise and worsening PM emissions under medium and large loads, HCCI combustion is limited to limited conditions of medium and low loads. At the same time, a completely homogeneous mixture is not easy to form in the cylinder. In order to improve the problem of limited operating conditions of HCCI, different methods have been tried 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 are different from the fuel used.

[0003] Using a single combustion mode cannot guarantee that the performance of the power unit is always optimal under all operating conditions. At the same time, using a single fuel cannot achieve the optimal performance under all operating conditions. In view of the problem of limited operating conditions under a single operating mode, it is proposed to use different combustion mode combinations to expand the load boundary of multi-mode combined combustion to achieve the optimal operation of the power unit under all operating conditions. However, multi-mode combined combustion inevitably faces the problem of mode switching. Due to the essential differences in fuel types and combustion mechanisms, the switching process directly leads to step changes in control parameters and changes in combustion reaction conditions during the combustion mode switching process, which causes the combustion mode switching process to be uneven, and fluctuations in parameters such as speed, combustion center of gravity, and IMEP, as well as 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 a first aspect, the present invention provides a control method for smooth switching of multiple modes of a power plant, and aims at the performance fluctuation problem caused by controller delay in the control system during the switching process of the combustion mode of a dual-fuel power plant, and corrects and compensates for the fuel amount during the switching process, including: receiving a combustion mode switching instruction, reading an input signal when operating in a 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 demand u0 for maintaining the current target speed according to the closed-loop speed deviation, and calculates the corrected fuel amount u when switching from the first combustion mode to the second combustion mode according to the equivalent energy principle; executing the control law when controlling fuel injection, and calculating the speed fluctuation rate of the system; wherein the control law is u=k·u0, k is the correction coefficient; comparing multiple groups of different corrected fuel amount values ​​and corresponding speed fluctuation rate results, and selecting 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 device, comprising:

[0007] A first processing module, for receiving a combustion mode switching instruction, reading an input signal when operating in a first combustion mode, and respectively confirming a fuel injection mode of the first combustion mode and a second combustion mode;

[0008] The second processing module is used to calculate the corrected fuel amount when switching from the first combustion mode to the second combustion mode according to the equivalent energy principle, and the controller calculates the initial fuel requirement for maintaining the current target speed according to the closed-loop speed deviation, and executes the control law when controlling the fuel injection; wherein the control law is u=k·u0, u is the corrected fuel amount, u0 is the initial fuel requirement, and k is the 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 rate 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 a control method for smooth multi-mode switching of a power device as described in any one of the 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 a 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 requirement during the multi-mode switching process. Therefore, the idea of ​​fuel demand correction compensation is adopted. At the moment of switching the combustion mode, 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, the following briefly introduces 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 creative work.

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

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

[0017] Figure 3 It 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 is a schematic diagram of the structure of an 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: Alcohol rail; 9: Methanol storage tank; 10: Emission analyzer; 11: Engine turbocharger; 12: First fuel supply system; 13: Second fuel supply system. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are 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 including 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 one..." do not exclude the existence of other identical elements in the process, method, article or device including 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", etc. in this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0024] At present, the switching of combustion modes between traditional combustion and low-temperature combustion is a unique and inevitable problem for diesel power plants. When the power plant is running, it is necessary to change the corresponding load when dealing with 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 range of working conditions 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 a more accurate calculation of the fuel amount during the switching process, making 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 plant, determine the controller and input / output signals, and establish an input / output control system.

[0027] The output signal of the established input / output control system is the actual speed and speed fluctuation rate of the controlled object, the input signal is the target speed, fuel low calorific value, switching enable signal and effective thermal efficiency, and the control target is the current working condition of the system. When the combustion mode needs to be switched, the output of the system can quickly and smoothly track the target speed of the system.

[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 performs reciprocating calculations to maintain stable operation of the system.

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

[0032] Based on the content of the above embodiment, as an optional embodiment, Figure 1 : is a flow chart of a control method for smooth multi-mode switching of a power device provided by the present invention, such as Figure 1 In view of 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, and 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 switching command, the algorithm is activated and starts to read the input signal when the system is running in the first combustion mode, and confirms the fuel injection mode of the first combustion mode and the second combustion mode respectively. The fuel injection mode refers to the number of fuel injections or the fuel injection method such as pure fuel single injection, fuel multiple injection, and two fuel injections.

[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: 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 for maintaining 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, u is the corrected fuel amount, u0 is the initial fuel requirement, and k is the correction coefficient.

[0038] The control rate starts to be executed after the system receives the mode switching instruction, and the controlled state variables are 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 and the target speed to obtain the initial fuel demand u0. The PID controller will continuously update the initial fuel demand u0 so that it can adapt to new operating conditions in each cycle and maintain stable operation of the system.

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

[0041]

[0042]

[0043] in, Refers to the effective work 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 a few 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 calorific value of the first fuel, Refers to the calorific value of the second fuel; under stable operating conditions, the system switches the combustion mode, and 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 setting that the crankshaft output effective work is equal before and after the switch, 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] Among them, B(t) refers to the fuel injection amount of the system per unit hour, and the following expression of speed is further 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 is 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 is a schematic diagram of a dual-fuel power plant structure 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 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 them, 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 realizing smooth multi-mode switching of a power plant using the above-mentioned dual-fuel power plant structure and using diesel and natural gas as two 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 3, for the multi-mode smooth switching control of the dual-fuel power plant, the input signal, output signal and control target of the control system are determined, and an input / output control system of 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, refer to 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 switching enable signal of the external combustion mode, the control system determines the current state of the power unit and performs basic fuel quantity management calculations for the power unit. When each switching condition is met, the system switching function starts to be activated, and the power unit switches from the CI combustion mode to the PCCI combustion mode;

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

[0073] Furthermore, when the pilot injection action is performed 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 the stable operation condition of the CI combustion mode is further obtained:

[0077]

[0078] in, Refers to the effective thermal efficiency within a few 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 switches to the PCCI combustion mode, it runs stably for a period of time and then changes the system switch enable again. Methanol fuel begins to be supplied into the cylinder, and the power unit begins to enter the combustion mode switching 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 starts, 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 used to look up 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 device, comprising:

[0092] A first processing module, for receiving a combustion mode switching instruction, reading an input signal when operating in a first combustion mode, and respectively confirming a fuel injection mode of the first combustion mode and a second combustion mode;

[0093] The second processing module is used to calculate the corrected fuel amount when switching from the first combustion mode to the second combustion mode according to the equivalent energy principle, and the controller calculates the initial fuel requirement for maintaining the current target speed according to the closed-loop speed deviation, and executes the control law when controlling the fuel injection; wherein the control law is u=k·u0, u is the corrected fuel amount, u0 is the initial fuel requirement, and k is the 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 rate 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 device provided in an embodiment of the present invention can, during specific operation, execute the control method for smooth multi-mode switching of a power device described in any of the above embodiments, which will not be elaborated in this embodiment.

[0097] Figure 4 is a 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 the smooth switching of the multi-mode of the power device.

[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 it is 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 to enable 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: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[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-mentioned embodiments.

[0100] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[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 embodiments of the present invention.

Claims

1. A control method for smooth switching of multiple modes 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 of 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 according to the equivalent energy principle, the initial fuel requirement for maintaining the current target speed is calculated according to the closed-loop speed deviation, the controller loads the initial fuel requirement, and executes the control law when controlling the fuel injection; wherein the control law is u=k·u0, u is the corrected fuel amount, u0 is the initial fuel requirement, and k is the correction coefficient; Calculate the speed fluctuation rate of the system under the action of the 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: The corrected fuel amount when switching from the first combustion mode to the second combustion mode is calculated according to the equivalent energy principle, including: Based on the crankshaft dynamics principle, the mathematical equation for effective work before and after switching is established: in, Refers to the effective work 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 a few 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 calorific value of the first fuel, 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 crankshaft output effective work 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 rotation 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 device, characterized in that: include: A first processing module, for receiving a combustion mode switching instruction, reading an input signal when operating in a first combustion mode, and respectively confirming a fuel injection mode of the first combustion mode and a second combustion mode; The second processing module is used to calculate the corrected fuel amount when switching from the first combustion mode to the second combustion mode according to the equivalent energy principle, calculate the initial fuel requirement for maintaining the current target speed according to the closed-loop speed deviation, and the controller loads the initial fuel requirement and executes the control law when controlling the fuel injection; wherein the control law is u=k·u0, u is the corrected fuel amount, u0 is the initial fuel requirement, and k is the 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 rate 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 device 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 described in any one of claims 1 to 7 are implemented.

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