Methanol-electric hybrid ship mode switching dynamic coordination control method and system

Abstract

This invention provides a dynamic coordinated control method and system for mode switching in methanol-electric hybrid power ships. The upper-level controller acquires real-time status information such as the ship's propeller load torque, methanol engine speed, permanent magnet synchronous motor speed, and the speed difference between the driving and driven ends of the clutch, and determines whether mode switching needs to be triggered. When switching is required, the upper-level controller generates target torques for the engine, motor, and clutch, sending the first two directly to the corresponding actuators, while sending the clutch target torque to the lower-level controller. Upon receiving the clutch target torque, the lower-level controller first calculates the clutch target oil pressure using the torque-oil pressure mapping relationship, then calculates the quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component, respectively. Finally, the three are added together to obtain the drive current, which is output to the clutch actuator, achieving precise closed-loop control of the clutch oil pressure.

Description

Technical Field

[0001] This invention relates to the field of marine new energy hybrid power system control technology, and in particular to a dynamic coordination control method and system for switching modes of methanol-electric hybrid power ships. Background Technology

[0002] Currently, methanol-electric hybrid power systems are receiving widespread attention as a clean and efficient solution to meet the energy conservation and emission reduction needs of the shipping industry. These systems typically include a methanol / diesel dual-fuel engine, an electric motor, a clutch, and a transmission system, and offer multiple operating modes such as pure electric propulsion, mechanical propulsion, and hybrid propulsion. The mode switching process, especially when switching from pure electric propulsion to mechanical propulsion, requires precise coordination among the engine, motor, and clutch to achieve a smooth transfer of power. Existing technologies include hierarchical coordinated control methods for mode switching in hybrid power systems. The upper layer is responsible for global torque distribution and timing planning, while the lower layer is responsible for tracking control of actuators (such as clutch hydraulic pressure and motor current). These methods have improved the switching quality to some extent and laid the foundation for technological development in this field.

[0003] However, existing control methods still have the following technical shortcomings when applied to parallel marine methanol-electric hybrid power systems. First, existing hierarchical coordinated control methods are mostly designed for traditional diesel engines or vehicle hybrid power systems, failing to fully consider the characteristics of methanol dual-fuel engines: short ignition delay, fast combustion speed, and significant differences in dynamic response characteristics compared to diesel engines. Directly using existing methods cannot achieve precise matching of the dynamic characteristics of the methanol engine and electric motor during mode switching transients, easily leading to torque fluctuations and speed oscillations, resulting in excessive ship impact and affecting sailing smoothness and transmission system lifespan. Second, existing research on marine hybrid power systems focuses on steady-state energy management strategies, paying insufficient attention to transient dynamic coordinated control during mode switching, lacking refined optimization of torque handover, clutch timing, and speed synchronization. This results in torque gaps or superposition during switching, exacerbating mechanical losses and fatigue risks. Third, ship systems are characterized by large inertia, slow dynamics, and susceptibility to strong load disturbances such as wind, waves, and currents. The parameters and logic of existing vehicle control methods have not been adapted to these characteristics. Direct migration and application will lead to problems such as control lag, insufficient tracking accuracy, and weak anti-disturbance capability. It is difficult to guarantee the stability and reliability of control under the complex working conditions of real ships.

[0004] Therefore, there is an urgent need for an innovative method that can adapt to the dynamic characteristics of methanol dual-fuel engines, overcome the effects of large inertia and strong disturbances of ships, and achieve refined dynamic coordination control throughout the mode switching process, so as to solve the problems of poor smoothness, insufficient robustness and weak dynamic coordination control in the existing technology. Summary of the Invention

[0005] This invention provides a dynamic coordination control method and system for switching modes in methanol-electric hybrid power ships, which solves the technical problems in the prior art, such as large impact during the switching process, poor smoothness, and insufficient control robustness under complex operating conditions, due to the failure to adapt to the dynamic characteristics of methanol dual-fuel engines and the lack of fine coordination for the transients of ship mode switching.

[0006] In a first aspect, embodiments of the present invention provide a dynamic coordination control method for mode switching in methanol-electric hybrid power ships, comprising: S1. Construct a hierarchical coordination control architecture, which includes an upper-level torque coordination controller and a lower-level actuator controller; S2. The upper-level torque coordination controller acquires the ship's real-time status information, which includes at least the propeller load torque, methanol engine speed, permanent magnet synchronous motor speed, and the speed difference between the main and driven ends of the clutch. S3. The upper-level torque coordination controller determines whether to trigger mode switching based on the real-time status information. If so, it generates upper-level control instructions based on the real-time status information and mode switching type. The upper-level control instructions include engine target torque, motor target torque and clutch target torque. S4. The upper-level torque coordination controller sends the engine target torque to the engine actuator, the motor target torque to the motor actuator, and the clutch target torque to the lower-level actuator controller. S5. The lower-level actuator controller calculates the clutch target oil pressure based on the received clutch target torque through the torque-oil pressure mapping relationship, and calculates the quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component based on the clutch target oil pressure. The quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component are added together to obtain the drive current of the clutch actuator; the drive current is then output to the clutch actuator.

[0007] Preferably, the methanol-electric hybrid power ship adopts a coaxial parallel hybrid power system; the methanol engine and the permanent magnet synchronous motor are coaxially connected through a wet clutch and jointly drive the propeller. The operating modes of the hybrid power system include pure electric propulsion mode, mechanical propulsion mode, hybrid propulsion mode, and charging propulsion mode; The mode switching includes at least switching between the pure electric propulsion mode and the mechanical propulsion mode, as well as switching between the mechanical propulsion mode and the hybrid propulsion mode.

[0008] Preferably, in step S3, the upper-level torque coordination controller determines whether to trigger a mode switch based on the real-time status information, including: When the propeller load torque is greater than a first load threshold and the battery state of charge is lower than a first state of charge threshold, an engine intervention switching is triggered; the engine intervention switching includes switching from the pure electric propulsion mode to the mechanical propulsion mode or the hybrid propulsion mode; When the propeller load torque is less than the second load threshold and the battery state of charge is higher than the second state of charge threshold, an engine exit mode switching is triggered; the engine exit mode switching includes switching from the mechanical propulsion mode or the hybrid propulsion mode to the pure electric propulsion mode. Alternatively, when the speed difference between the driving and driven ends of the clutch is less than the speed difference threshold and the clutch actuator is in a disengaged state, the clutch is triggered to engage in order to switch the operating mode.

[0009] Preferably, in step S3, generating the engine target torque specifically includes: An integral sliding surface is constructed using the difference between the desired engine speed and the actual engine speed; Based on the integral sliding surface, the equivalent control terms are calculated using the methanol engine dynamics model. Using the integral sliding surface and its derivative as input, the adaptive switching gain is calculated in real time through fuzzy logic rules; wherein the adaptive switching gain is positively correlated with the absolute value of the integral sliding surface and the absolute value of its derivative. The engine target torque is generated using a control law containing a hyperbolic tangent function, based on the equivalent control term and the adaptive switching gain.

[0010] Preferably, generating the target torque of the motor in step S3 specifically includes: Calculate the motor reference torque based on the propeller load torque and transmission system parameters; Obtain the motor reference torque at the current moment, the motor reference torque at the first historical moment, and the motor reference torque at the second historical moment; Initialize the first scaling factor, the second scaling factor, the first delay time, and the second delay time; and optimize the first scaling factor, the second scaling factor, the first delay time, and the second delay time online by accelerating the particle swarm optimization algorithm with the goal of minimizing the propeller speed deviation. Using the optimized first scaling factor, second scaling factor, first delay time, and second delay time, the motor reference torque at the current moment, the motor reference torque at the first historical moment, and the motor reference torque at the second historical moment are weighted and summed to generate the wave superposition base torque; Calculate the deviation between the desired propeller speed and the actual propeller speed, perform proportional-derivative control on the deviation, and generate feedback compensation torque; The target torque of the motor is obtained by adding the wave superposition base torque to the feedback compensation torque.

[0011] Preferably, step S3 further includes timing coordination control: Based on the relationship between the speed difference between the clutch driving and driven ends and the preset speed difference threshold, the mode switching process is divided into a preparation stage, a switching stage, and a stabilization stage. During the preparation phase, the permanent magnet synchronous motor is controlled to bear the propeller load torque alone, the methanol engine is controlled to accelerate to be synchronized with the permanent magnet synchronous motor, and the clutch actuator is pre-charged with oil to a low pressure state. During the switching phase, when the speed difference between the driving and driven ends of the clutch is less than the preset speed difference threshold, the oil pressure of the clutch actuator is controlled to rise, the target torque of the engine is controlled to rise linearly, and the target torque of the motor is controlled to fall linearly; wherein, the rate of increase of the target torque of the engine is equal to the rate of decrease of the target torque of the motor, and both the rate of increase and the rate of decrease are less than or equal to the preset maximum rate constraint value. During the stabilization phase, once the clutch actuator is fully engaged, the oil pressure of the clutch actuator is controlled to rise to the rated value, and the sum of the engine target torque and the motor target torque is controlled to equal the propeller load torque.

[0012] Preferably, in step S5, the calculation of the quasi-steady-state control current component, the dynamic feedforward compensation current component, and the nonlinear error feedback correction current component respectively includes: Based on the current-oil pressure steady-state characteristic curve of the solenoid valve and the target oil pressure of the clutch, the quasi-steady-state control current component is calculated; the quasi-steady-state control current component is used to compensate for the steady-state oil pressure demand. The dynamic feedforward compensation current component is calculated based on the rate of change of the target oil pressure of the clutch and the dynamic characteristic coefficient of the hydraulic system; the dynamic feedforward compensation current component is used to compensate for the oil pressure response delay. Based on the deviation between the actual clutch oil pressure and the target clutch oil pressure, an exponential nonlinear feedback law is used to calculate the nonlinear error feedback correction current component; in the exponential nonlinear feedback law, when the absolute value of the deviation increases, the nonlinear error feedback correction current increases exponentially.

[0013] As a preferred option, it also includes: S6. Reacquire the ship's real-time status information; based on the reacquired real-time status information, calculate the engine speed error, motor speed error, and the oil pressure tracking error between the actual clutch oil pressure and the clutch target oil pressure; The engine speed error and the motor speed error are fed back to the upper-level torque coordination controller; the upper-level torque coordination controller updates the engine target torque and motor target torque for the next control cycle based on the engine speed error and the motor speed error; The hydraulic pressure tracking error is fed back to the lower-level actuator controller; the lower-level actuator controller updates the drive current for the next control cycle based on the hydraulic pressure tracking error.

[0014] As a preferred option, a mode switching completion determination step is also included: After the closed-loop feedback step, the ship's impact, propeller speed fluctuation, and oil pressure tracking error between the actual clutch oil pressure and the clutch target oil pressure are calculated in real time. When the impact is less than or equal to a preset impact threshold, the propeller speed fluctuation is less than or equal to a preset speed fluctuation threshold, the oil pressure tracking error is less than or equal to a preset oil pressure error threshold, and the clutch actuator is in a fully engaged state, the judgment mode switch is completed. After the determination is completed, the current distribution ratio of engine target torque and motor target torque is maintained, and the mode switching control process is exited; if the determination is not completed, the process returns to step S2 to continue execution.

[0015] Secondly, embodiments of the present invention provide a dynamic coordination control system for switching modes in a methanol-electric hybrid power ship, comprising: An upper-level torque coordination controller and a lower-level actuator controller are communicatively connected to form a hierarchical coordination control architecture. The upper-level torque coordination controller is used to acquire the ship's real-time status information, which includes at least the propeller load torque, methanol engine speed, permanent magnet synchronous motor speed, and the speed difference between the main and driven ends of the clutch. The upper-level torque coordination controller is also used to determine whether to trigger mode switching based on the real-time status information. If so, it generates upper-level control instructions based on the real-time status information and mode switching type. The upper-level control instructions include engine target torque, motor target torque and clutch target torque. The upper-level torque coordination controller sends the engine target torque to the engine actuator, the motor target torque to the motor actuator, and the clutch target torque to the lower-level actuator controller; The lower-level actuator controller is used to calculate the target clutch oil pressure based on the received target clutch torque through the torque-oil pressure mapping relationship, and to calculate the quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component based on the target clutch oil pressure. The quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component are added together to obtain the drive current of the clutch actuator; the drive current is then output to the clutch actuator.

[0016] This invention provides a dynamic coordinated control method and system for mode switching in methanol-electric hybrid power ships, constructing a hierarchical coordinated control architecture consisting of an upper-level torque coordination controller and a lower-level actuator controller. The upper-level controller acquires real-time status information such as the ship's propeller load torque, methanol engine speed, permanent magnet synchronous motor speed, and the speed difference between the driving and driven ends of the clutch, and determines whether mode switching needs to be triggered. When switching is required, the upper-level controller generates target torque for the engine, motor, and clutch, sending the first two directly to the corresponding actuators, while sending the clutch target torque down to the lower-level controller. Upon receiving the clutch target torque, the lower-level controller first calculates the clutch target oil pressure through the torque-oil pressure mapping relationship, then calculates the quasi-steady-state control current component (based on the steady-state characteristics of the solenoid valve), the dynamic feedforward compensation current component (based on the oil pressure change rate), and the nonlinear error feedback correction current component (based on the deviation between the actual oil pressure and the target oil pressure), and finally adds the three to obtain the drive current, which is output to the clutch actuator, thereby achieving precise closed-loop control of the clutch oil pressure. Compared with existing technologies, this method has the following advantages: (1) Through the division of labor and cooperation between the upper and lower layers, the upper layer optimizes the torque distribution and the lower layer compensates for the large inertia and long delay characteristics of the hydraulic system, effectively overcoming the switching shock caused by the mismatch between the dynamic response of the methanol engine and the motor, making the clutch engagement process smoother and the oil pressure tracking error significantly reduced.

[0017] (2) The three-step control strategy combining quasi-steady state, feedforward and nonlinear feedback can quickly respond to load disturbances and suppress oil pressure overshoot, and finally achieve smooth torque transfer, small speed fluctuation and low impact during mode switching, which significantly improves the smoothness of ship navigation, ride comfort and service life of transmission system. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart of the dynamic coordination control method for switching modes of methanol-electric hybrid power ships provided in an embodiment of the present invention; Figure 2 A structural diagram of a parallel ship methanol-electric hybrid power system provided in an embodiment of the present invention; Figure 3 A flowchart illustrating the switching process from electric propulsion to mechanical propulsion provided in an embodiment of the present invention; Figure 4 This is a hierarchical optimized dynamic coordination control structure diagram of a parallel ship methanol-electric hybrid power system provided in an embodiment of the present invention; Figure 5 The flowchart of the hierarchical optimization dynamic coordination control algorithm for a parallel ship methanol-electric hybrid power system provided in this embodiment of the invention is shown below. Figure 6 This is a schematic diagram of the dynamic coordination control system for switching modes of a methanol-electric hybrid power ship, provided in an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Figure 1 This is a flowchart of the dynamic coordination control method for mode switching of methanol-electric hybrid power ships according to an embodiment of the present invention, with reference to... Figure 1 , Figure 2 , Figure 4 , Figure 5 The method includes: S1. Construct a hierarchical coordination control architecture, which includes an upper-level torque coordination controller and a lower-level actuator controller.

[0022] The hierarchical coordination control architecture decomposes the complex mode switching control task into two independent yet collaborative layers: decision-making and execution. The upper layer is responsible for global torque planning and timing logic, while the lower layer is responsible for the precise driving of specific actuators. In this embodiment, the upper-layer torque coordination controller is a controller that makes torque distribution and switching timing decisions for power sources (engines, motors, clutches) based on the ship's navigation status (load, speed, SOC, etc.). The lower-layer actuator controller is specifically used to drive clutch actuators (such as solenoid valves and hydraulic cylinders) to achieve high-precision tracking of clutch oil pressure.

[0023] Existing ship hybrid power control systems often employ centralized or simple threshold logic, lacking a clear division of labor between upper-level energy management and lower-level actuators. This leads to a disconnect between torque coordination and clutch action during mode switching, resulting in significant shocks. By constructing a separate upper and lower-level architecture, this embodiment systematically solves the problems of coupling between decision-making and execution, and mismatched response speeds, laying the foundation for subsequent refined control.

[0024] S2. The upper-level torque coordination controller acquires the ship's real-time status information, which includes at least the propeller load torque, methanol engine speed, permanent magnet synchronous motor speed, and the speed difference between the main and driven ends of the clutch.

[0025] Among them, the propeller load torque is the water resistance torque experienced by the propeller when it rotates, which is determined by the ship speed, propeller speed, and seawater density, and directly reflects the ship's current power demand; the methanol engine speed is the crankshaft speed of the methanol / diesel dual-fuel engine, and its dynamic response is affected by the methanol substitution rate and the in-cylinder combustion process; the permanent magnet synchronous motor speed is the speed of the motor coaxially connected to the propeller, and the propeller speed can be obtained by converting the transmission ratio; the clutch driving and driven end speed difference is the speed difference between the engine output shaft and the motor input shaft (or transmission shaft), which is a key indicator for judging whether the clutch can engage smoothly.

[0026] Existing technologies often only collect motor speed or load torque, neglecting engine speed difference and clutch status, leading to blind switching decisions. The four state variables collected in this step cover the three core dimensions of power source, load, and clutch, and can fully describe the dynamic conditions at the moment of switching, solving the problems of insufficient information and single decision-making basis.

[0027] S3. The upper-level torque coordination controller determines whether to trigger mode switching based on the real-time status information. If so, it generates upper-level control commands based on the real-time status information and mode switching type. The upper-level control commands include engine target torque, motor target torque, and clutch target torque.

[0028] Among them, trigger mode switching refers to the system actively switching from the current working mode (such as pure electric propulsion) to another mode (such as mechanical propulsion or hybrid propulsion) when the load, SOC, or speed difference meets the preset threshold. The mode switching types include pure electric → mechanical, pure electric → hybrid, mechanical → hybrid, and reverse switching. The engine target torque is the expected output torque allocated to the methanol engine by the upper layer, which is generated by the fuzzy adaptive sliding mode control algorithm. The motor target torque is the motor torque command reconstructed by the improved wave superposition method to suppress load disturbances. The clutch target torque is the expected friction torque that the clutch needs to transmit during the switching process, which is used for subsequent oil pressure mapping.

[0029] Existing ship mode switching relies solely on threshold logic, lacking torque coordination during the switching process, leading to shocks caused by sudden torque changes in the engine and motor. This new step, upon trigger detection, simultaneously generates three target torques and employs dedicated algorithms, such as FSMC (Fuzzy Adaptive Sliding Mode Control) and IWSM (Improved Wave Superposition Method), to address the dynamic characteristics of the methanol engine and propeller load fluctuations. This achieves synchronized torque increases and decreases and rate matching between the engine and motor, resolving the issues of dynamic characteristic mismatch and uneven torque handover.

[0030] S4. The upper-level torque coordination controller sends the engine target torque to the engine actuator, the motor target torque to the motor actuator, and the clutch target torque to the lower-level actuator controller.

[0031] The engine actuators mainly include the engine electronic control unit (ECU), which achieves the target torque by adjusting the throttle opening, methanol injection quantity, and diesel injection quantity; the electric motor actuators refer to the motor controller, which adjusts... d / q The shaft current controls the output torque of the permanent magnet synchronous motor; the lower-level actuator controller is a controller specifically designed for the clutch hydraulic system, which receives the target clutch torque and converts it into hydraulic commands.

[0032] In traditional hierarchical control, the upper layer only sends commands to the engine and electric motor, while clutch commands are often missing or controlled by independent logic, leading to asynchrony between clutch action and torque regulation. This step explicitly includes the target clutch torque in the upper-layer commands and sends it specifically to the lower layer, achieving synchronous linkage between torque coordination and clutch engagement. This solves the problems of clutch action lag and torque and hydraulic pressure decoupling, ensuring the consistency of the timing of engine torque reduction, electric motor torque increase, and clutch hydraulic pressure increase. It avoids torque superposition or gaps, making the switching process smoother and reducing the burden on the lower-layer controller to guess the switching intention.

[0033] S5. The lower-level actuator controller calculates the clutch target oil pressure based on the received clutch target torque through the torque-oil pressure mapping relationship, and calculates the quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component based on the clutch target oil pressure. The quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component are added together to obtain the drive current of the clutch actuator; the drive current is then output to the clutch actuator.

[0034] Among them, the torque-oil pressure mapping relationship is an inherent characteristic of wet clutches: the transmitted torque is proportional to the oil pressure, and the proportional coefficient depends on the number of friction surfaces, friction coefficient, etc.; the quasi-steady-state control current component calculates the base current required to maintain the target oil pressure based on the steady-state current-oil pressure characteristic curve (IP curve) of the solenoid valve; the dynamic feedforward compensation current component increases or decreases the current in advance according to the rate of change of the target oil pressure to overcome the response delay of the hydraulic pipeline; the nonlinear error feedback correction current component uses the deviation between the actual oil pressure and the target oil pressure to generate a correction current according to an exponential law, and the larger the deviation, the stronger the correction effect; the drive current is the excitation current supplied to the proportional solenoid valve, which directly controls the valve core position and thus adjusts the clutch oil pressure.

[0035] Marine clutch hydraulic systems are characterized by long pipelines, high inertia, and strong nonlinearity. Traditional PID or open-loop control suffers from severe overshoot and lag, leading to clutch engagement shock. This approach employs a three-step method: the steady-state component eliminates static errors, the feedforward component dynamically compensates for delays, and the nonlinear feedback component suppresses disturbances and model errors. These three steps are superimposed to form a complete control law. This solves the prominent problems of low hydraulic pressure tracking accuracy, slow response, and large shocks in marine clutches.

[0036] Based on the above embodiments, as a preferred implementation, the methanol-electric hybrid power ship adopts a coaxial parallel hybrid power system; the methanol engine and the permanent magnet synchronous motor are coaxially connected through a wet clutch and jointly drive the propeller.

[0037] The hybrid power system operates in the following modes: pure electric propulsion, mechanical propulsion, hybrid propulsion, and charging propulsion.

[0038] The mode switching includes at least switching between the pure electric propulsion mode and the mechanical propulsion mode, as well as switching between the mechanical propulsion mode and the hybrid propulsion mode.

[0039] Specifically, in this embodiment, the parallel methanol-electric hybrid power system adopts a coaxial parallel structure, as shown in the following diagram. Figure 2 As shown, it mainly consists of a methanol / diesel dual-fuel engine, a permanent magnet synchronous reversible motor, a lithium iron phosphate battery pack, a clutch, a transmission system, and a propeller. The engine is coaxially connected to the motor via the clutch, jointly driving the propeller to propel the ship. The system has four operating modes: electric propulsion (Power Take Home, PTH), mechanical propulsion (MP), hybrid propulsion (Boost), and power take-off (PTO). Mode switching is achieved through clutch engagement / disengagement and power source torque coordination.

[0040] Furthermore, the methanol engine model adopts a modeling approach combining the average value method and the volumetric method, considering the cylinder thermodynamic process and the methanol-diesel dual-fuel supply characteristics, to establish an engine torque output model: =

[0041] In the formula, f This represents a functional relationship, specifically the output torque of the methanol engine. T e It is determined by engine speed Methanol substitution rate and cylinder pressure A nonlinear function determined by three variables. This provides the output torque for the methanol engine; Engine speed; Methanol substitution rate; The in-cylinder pressure is used to reflect the engine's dynamic response characteristics by coupling the combustion heat release rate model with the dynamic subsystem equations.

[0042] Permanent magnet synchronous motor model, based on d , q The state-space equations in the coordinate system consider the relationship between the electromagnetic torque and speed of the motor:

[0043] In the formula, This refers to the electromagnetic output torque of a permanent magnet synchronous motor. For extreme logarithms, It is a permanent magnet flux linkage. , They are respectively d / q Shaft inductor, , They are respectively d / q Shaft current reflects the motor's advantage of rapid torque response.

[0044] Clutch and transmission system model, the clutch adopts a wet clutch model, considering the oil pressure-torque transmission characteristics.

[0045] In the formula, Torque is transmitted through friction in a wet clutch. These are the outer and inner radii of the clutch friction plate; This represents the number of clutch friction plate pairs. The coefficient of kinetic friction of the friction plate; This refers to the axial clamping force of the clutch; This is the speed difference between the driving and driven ends of the clutch.

[0046] The transmission system includes a gearbox and a drive shaft. Considering torsional stiffness and damping characteristics, a torque transmission model is established: =

[0047] In the formula, This is the effective torque output from the transmission system to the propeller; This provides the output torque for the methanol engine; This is the output torque of the permanent magnet synchronous motor; The transmission ratio is... For gearbox efficiency.

[0048] The propeller model, based on the ship's propulsion characteristics, assumes that the propeller thrust and torque satisfy the following conditions:

[0049]

[0050] In the formula, This refers to the axial thrust of the propeller. To absorb torque (resistive torque) for the propeller; , These are the thrust coefficient and the torque coefficient, respectively. The propeller speed, D The diameter of the propeller. ρ This refers to the density of seawater.

[0051] Based on the above embodiments, as a preferred implementation, in step S3, the upper-level torque coordination controller determines whether to trigger a mode switch based on the real-time status information, including: When the propeller load torque is greater than the first load threshold and the battery state of charge is lower than the first state of charge threshold, an engine intervention switching is triggered; the engine intervention switching includes switching from the pure electric propulsion mode to the mechanical propulsion mode or the hybrid propulsion mode.

[0052] When the propeller load torque is less than the second load threshold and the battery state of charge is higher than the second state of charge threshold, an engine exit mode switching is triggered; the engine exit mode switching includes switching from the mechanical propulsion mode or the hybrid propulsion mode to the pure electric propulsion mode.

[0053] Alternatively, when the speed difference between the driving and driven ends of the clutch is less than the speed difference threshold and the clutch actuator is in a disengaged state, the clutch is triggered to engage in order to switch the operating mode.

[0054] Specifically, the upper-level torque coordination controller in this step monitors the propeller load torque in real time. TL Battery state of charge (SOC) and the speed difference between the driving and driven ends of the clutch ω cl It is compared with a preset threshold to determine whether to initiate mode switching. Specifically, when T L Greater than the first load threshold And the SOC is lower than the first charge threshold. This indicates that the ship is under high load and low battery power, requiring engine intervention to provide additional power or maintain navigation capability, triggering engine intervention switching, i.e., switching from pure electric propulsion mode to mechanical propulsion mode or hybrid propulsion mode; when T L Less than the second load threshold (Usually the same as or different from the first threshold) and the SOC is higher than the second charge threshold. When the load is low and the battery is sufficiently charged, the engine can be disengaged to save fuel and the electric motor can be used for efficient drive, triggering an engine disengagement switch, i.e., switching from mechanical propulsion mode or hybrid propulsion mode back to pure electric propulsion mode; in addition, when the speed difference between the clutch driving and driven ends... ω cl Less than the preset speed difference threshold ω th And the clutch actuator is in the disengaged state ( S cl When the speed of the engine and motor is synchronized (=0), it indicates that the conditions for smooth clutch engagement are met. This also triggers a mode switch, typically used for clutch engagement before switching from pure electric propulsion to mechanical or hybrid propulsion. These three conditions are independent triggering logics; the corresponding mode switch process is initiated when any one of them is met.

[0055] Compared to existing technologies that rely solely on a single threshold (such as load or speed) for hard switching, this step introduces a multi-dimensional state joint judgment mechanism. In particular, it couples battery SOC with load torque, avoiding power interruption caused by forced pure electric propulsion when battery power is insufficient, or increased fuel consumption due to inefficient engine operation under low load. Through precise threshold comparison and mode type classification, this step can plan the power source switching timing in advance, ensuring that engine intervention or withdrawal always occurs within the window of optimal system efficiency and minimal impact. This effectively solves the technical problems of existing mode switching decisions being crude and prone to torque abrupt changes and speed oscillations, providing a clear direction for subsequent torque coordination and clutch control, and ultimately achieving a smooth, efficient, and robust switching process.

[0056] Based on the above embodiments, as a preferred implementation, in step S3, generating the engine target torque specifically includes: An integral sliding surface is constructed using the difference between the desired and actual engine speeds. Specifically, for mechanical path torque control, to address the propeller load-side torque stability requirements, an improved wave superposition method (IWSM) is used to optimize the motor torque command, and load disturbances are suppressed through torque reconstruction and feedback compensation.

[0057] In the formula, Optimized torque control commands for the motor; s 1. s 2 is the scaling factor; This is the original basic torque command for the motor; , To delay time, For feedback gain, To address the propeller speed deviation, the parameter combination was optimized using the Accelerated Particle Swarm Optimization (APSO) algorithm.

[0058] To address the requirement for stable engine speed, fuzzy adaptive sliding mode control (FSMC) is employed to optimize the distribution of engine torque and clutch torque, resisting engine excitation disturbances. Sliding surface design:

[0059] In the formula, To provide the sliding surface function for sliding mode control; This refers to the actual engine speed. The target engine speed; is the sliding mode surface integral gain coefficient.

[0060] By combining the equivalent control term with the fuzzy adaptive arrival law, the switching gain is dynamically adjusted to avoid chattering.

[0061] in, Optimize the torque control command for the engine; This is the equivalent control term for sliding mode control. For fuzzy adaptive gain; It is the hyperbolic tangent function.

[0062] Based on the integral sliding surface, the equivalent control terms are calculated using the methanol engine dynamics model. The derivative is obtained with respect to the sliding surface, and then combined with the methanol engine dynamics model. ,in, Engine rotational inertia The clutch transmits torque. Engine loss torque, calculate equivalent control term (sliding surface) s Engine torque at =0):

[0063] Using the integral sliding surface and its derivative as input, the adaptive switching gain is calculated in real time through fuzzy logic rules; wherein the adaptive switching gain is positively correlated with the absolute value of the integral sliding surface and the absolute value of its derivative.

[0064] Design a fuzzy adaptive arrival law, with inputs being the sliding surface s and its derivative. The output is the adaptive switching gain η(t), and the fuzzy rule is: if s is large and Large → Increase η (t), accelerates the approach to the sliding surface; if s is small and Decrease η(t) to suppress sliding mode chattering.

[0065] The engine target torque is generated using a control law containing a hyperbolic tangent function, based on the equivalent control term and the adaptive switching gain.

[0066] Synthesize the engine sliding mode control law to generate the engine target torque:

[0067] Where ε>0 is the boundary layer parameter, which reduces chattering and limits engine torque to the optimal range for methanol combustion.

[0068] Based on the above embodiments, as a preferred implementation, in step S3, the target torque of the motor is generated, and the target torque of the motor is reconstructed using the improved wave superposition method (IWSM). Combined with speed deviation feedback compensation, the wave superposition parameters are optimized online using an accelerated particle swarm optimization algorithm to ensure that the motor torque quickly tracks the load demand. Specifically, this includes: Calculate the motor reference torque based on the propeller load torque and transmission system parameters. (Based on the propeller load torque...) Calculate the motor's reference torque , i Gear ratio, For transmission efficiency.

[0069] Obtain the motor reference torque at the current moment, the motor reference torque at the first historical moment, and the motor reference torque at the second historical moment.

[0070] First, initialize the first scaling factor. Second scaling factor First delay time Second delay time Then, the propeller speed deviation Δ ωp = ω pd ωp Minimization is the optimization objective, and the Accelerated Particle Swarm Optimization (APSO) algorithm is used for online iterative updates. s 1. s 2. Δ t 1. Δ t The optimal value of 2. During the optimization process, the range of values ​​for each parameter satisfies: 0 ≤ s 1, s 2≤10≤ s 1, s 2≤1, s 1+ s 2≤1, Δ t 1>0, Δ t 2>0 and Δ t 1≠Δ t 2. The APSO algorithm searches for the parameter combination that minimizes the absolute value integral or square integral of the rotational speed deviation within the feasible region using the particle position and velocity update formulas, and utilizes an acceleration factor to speed up the convergence. After a finite number of iterations, it outputs the optimized parameters, which are used for the weighted summation of the underlying torque in subsequent wave superposition.

[0071] Using the optimized first scaling factor, second scaling factor, first delay time, and second delay time, the motor reference torque at the current moment, the motor reference torque at the first historical moment, and the motor reference torque at the second historical moment are weighted and summed to generate the wave superposition base torque.

[0072] Data collection of historical reference torque , An improved wave superposition torque model is constructed: .

[0073] The deviation between the desired propeller speed and the actual propeller speed is calculated, and proportional-derivative control is applied to the deviation to generate feedback compensation torque.

[0074] Calculate propeller speed deviation ,in, To determine the desired propeller speed based on the ship's speed requirements, a proportional feedback compensation term is designed: .in, For proportional gain, The differential gain is used to suppress speed overshoot.

[0075] The target torque of the motor is obtained by adding the wave superposition base torque to the feedback compensation torque. The scaling factor is optimized online using the APSO algorithm. , and delay time , The optimization objective is the speed deviation. Minimum; final target torque of the synthesized motor: Limit the motor torque within the rated range: .

[0076] Based on the above embodiments, as a preferred implementation, step S3 further includes timing coordination control: Based on the relationship between the speed difference between the driving and driven ends of the clutch and the preset speed difference threshold, the mode switching process is divided into a preparation stage, a switching stage, and a stabilization stage.

[0077] The mode switching process is essentially a coordinated process of power source torque redistribution and clutch state transition. Taking the switch from electric propulsion mode to mechanical propulsion mode as an example, there are three typical stages: (1) Preparation stage: The motor torque maintains the load demand, the engine starts and accelerates to synchronous speed, and the clutch begins to fill with oil. (2) Switching stage: The clutch gradually engages and transmits torque, the motor torque gradually decreases, and the engine torque increases synchronously. (3) Stable stage: The clutch is fully engaged, the engine provides load torque alone, and the motor enters standby state.

[0078] The process of switching from electric propulsion to mechanical propulsion, such as... Figure 3 As shown. Problems that may occur during the switching process include: torque gap caused by mismatch between engine and motor torque response speeds, slippage loss and impact caused by clutch oil pressure adjustment delay, and speed fluctuations caused by increased propeller load disturbance. These problems all need to be solved through precise dynamic coordination control.

[0079] During the preparation phase, the permanent magnet synchronous motor is controlled to solely bear the propeller load torque, the methanol engine is controlled to accelerate to synchronization with the permanent magnet synchronous motor, and the clutch actuator is pre-charged with oil to a low-pressure state. Specifically, during the preparation phase: → The motor alone bears the load torque The engine speed increased to Pre-charge the clutch with oil to low pressure. .

[0080] During the switching phase, when the speed difference between the driving and driven ends of the clutch is less than the preset speed difference threshold, the oil pressure of the clutch actuator is controlled to rise, the target torque of the engine is controlled to rise linearly, and the target torque of the motor is controlled to fall linearly; wherein, the rate of increase of the target torque of the engine is equal to the rate of decrease of the target torque of the motor, and both the rate of increase and the rate of decrease are less than or equal to the preset maximum rate constraint value.

[0081] During the transition phase: →As the clutch begins to pressurize, the engine torque increases linearly, while the motor torque decreases linearly. To ensure a smooth torque transfer, the rate of increase of the engine's target torque and the rate of decrease of the motor's target torque must satisfy a rate matching relationship: .

[0082] During the stabilization phase, once the clutch actuator is fully engaged, the oil pressure of the clutch actuator is controlled to rise to its rated value, and the sum of the engine target torque and the motor target torque is controlled to equal the propeller load torque. During the stabilization phase: (Fully engaged) → Clutch oil pressure reaches rated value, engine alone / in conjunction with motor to bear load torque. .

[0083] Based on the above embodiments, as a preferred implementation, step S5, which calculates the quasi-steady-state control current component, the dynamic feedforward compensation current component, and the nonlinear error feedback correction current component, specifically includes: Based on the current-oil pressure steady-state characteristic curve (IP curve) of the solenoid valve and the target oil pressure of the clutch, the quasi-steady-state control current component is calculated; the quasi-steady-state control current component is used to compensate for the steady-state oil pressure demand; based on the IP characteristic curve of the solenoid valve, the steady-state relationship between oil pressure and excitation current is established: In the formula, This refers to the steady-state oil pressure of the clutch. This is the driving current for the solenoid valve; The linear fitting coefficients for the IP characteristics of the solenoid valve are given.

[0084] Among them, according to the torque-oil pressure mapping model of wet clutch z is the number of friction surfaces. Given the coefficient of friction, calculate the target oil pressure for the clutch: Limit the oil pressure range: .

[0085] Based on the steady-state characteristics of the solenoid valve's IP (current-oil pressure) voltage, a basic excitation current is generated to compensate for the steady-state oil pressure requirement. E is the damping coefficient of the hydraulic system, and F is the feedforward compensation coefficient.

[0086] Based on the rate of change of the target oil pressure of the clutch and the dynamic characteristic coefficient of the hydraulic system, the dynamic feedforward compensation current component is calculated; the dynamic feedforward compensation current component is used to compensate for the oil pressure response delay; to compensate for the dynamic response delay of the oil pressure, a feedforward command is designed based on the expected rate of change of oil pressure, and the dynamic feedforward compensation current component is calculated:

[0087] In the formula, For feedforward control to compensate for the current component; denoted as the desired rate of change of oil pressure; E is the damping coefficient of the hydraulic system; and F is the feedforward compensation coefficient. This refers to the actual oil pressure of the clutch. This is the target oil pressure for the clutch. This component can increase or decrease the current in advance to compensate for the lag in the oil pressure build-up process, allowing the actual oil pressure to follow the target value more quickly.

[0088] Based on the deviation between the actual clutch oil pressure and the target clutch oil pressure, an exponential nonlinear feedback law is used to calculate the nonlinear error feedback correction current component; in the exponential nonlinear feedback law, when the absolute value of the deviation increases, the nonlinear error feedback correction current increases exponentially.

[0089] Based on the actual clutch oil pressure With clutch target oil pressure The deviation Δp = The nonlinear error feedback correction current component is calculated using an exponential nonlinear feedback law:

[0090] In the formula, For nonlinear feedback correction current; κ , λ For nonlinear feedback adjustment parameters; F is the dynamic characteristic coefficient of the hydraulic system. When the deviation Δ p As the absolute value of λ increases, Δp The term will increase rapidly according to an exponential law, thereby... The absolute value of the error also increases exponentially, meaning the larger the error, the stronger the feedback correction effect. This nonlinear feedback can effectively suppress hydraulic system model errors and external disturbances, ensuring the steady-state accuracy of oil pressure tracking.

[0091] The steady-state control current component Dynamic feedforward compensation current component and nonlinear error feedback correction current component Adding them together, we get the final drive current of the clutch solenoid valve: I s =u s+u f +u e .

[0092] This current is output to the solenoid valve, controlling the valve spool displacement to regulate the clutch oil pressure. The current range must be limited. I s min ≤ I s ≤ I s max This is to protect the solenoid valve and prevent overcurrent.

[0093] Based on the above embodiments, as a preferred implementation, it further includes: S6. Reacquire the ship's real-time status information; calculate the engine speed error based on the reacquired real-time status information. Motor speed error and the actual oil pressure of the clutch With clutch target oil pressure Oil pressure tracking error between .

[0094] The engine speed error and the motor speed error Feedback is sent to the upper-level torque coordination controller; the upper-level torque coordination controller updates the engine target torque for the next control cycle based on the engine speed error and the motor speed error. and motor target torque This is to eliminate speed deviations and ensure precise coordination of the power source torque.

[0095] The oil pressure tracking error Δ p cl Feedback is sent to the lower-level actuator controller; the lower-level actuator controller, based on the hydraulic pressure tracking error, recalculates and updates the drive current for the next control cycle using a nonlinear three-step method (quasi-steady-state + dynamic feedforward + nonlinear error feedback). I s This allows for more precise tracking of the target oil pressure in the clutch, compensating for the nonlinearity, time-varying characteristics, and external disturbances of the hydraulic system.

[0096] Based on the above embodiments, as a preferred implementation, a mode switching completion determination step is also included: After the closed-loop feedback step, the ship's impact, propeller speed fluctuation, and oil pressure tracking error between the actual clutch oil pressure and the clutch target oil pressure are calculated in real time.

[0097] Specifically, after the closed-loop feedback step (i.e., after completing one full control cycle iteration), the following three evaluation metrics are calculated in real time: Ship impact , which is the rate of change of ship acceleration 'a', expressed in m / s³. Impact intensity directly reflects the severity of torque surges during mode switching and is a core indicator for evaluating ride comfort.

[0098] propeller speed fluctuation value This is the absolute value of the difference between the desired speed and the actual speed, expressed in rad / s. Smaller speed fluctuations indicate a smoother torque transfer from the power source.

[0099] Clutch oil pressure tracking error Hydraulic pressure tracking accuracy is the absolute value of the difference between the actual hydraulic pressure and the target hydraulic pressure, expressed in Pa. The accuracy of hydraulic pressure tracking directly affects the smoothness of the torque transmitted by the clutch.

[0100] When the impact is less than or equal to a preset impact threshold, the propeller speed fluctuation is less than or equal to a preset speed fluctuation threshold, the oil pressure tracking error is less than or equal to a preset oil pressure error threshold, and the clutch actuator is in a fully engaged state, the judgment mode switch is completed.

[0101] The judgment mode switch is completed when all four of the following conditions are met: Mode switching complete

[0102] After the determination is completed, the current distribution ratio of engine target torque and motor target torque is maintained, and the mode switching control process is exited; if the determination is not completed, the process returns to step S2 to continue execution.

[0103] Decision complete: Maintain the current engine target torque. and motor target torque The allocation ratio (i.e., the locked torque allocation value) is determined, and the mode switching control process is exited, so that the system can operate stably in the current working mode.

[0104] If the judgment is not completed: Do not exit the switching process, but return to step S2, reacquire the real-time status information, and continue to execute steps S3, S4, S5, S6 (closed-loop feedback) and this judgment step to form a closed-loop iteration until all conditions are met.

[0105] Secondly, embodiments of the present invention provide a dynamic coordination control system for switching modes in a methanol-electric hybrid power ship, such as... Figure 6 As shown, it includes: An upper-level torque coordination controller 610 and a lower-level actuator controller 620 are communicatively connected to form a hierarchical coordination control architecture.

[0106] The upper-level torque coordination controller 610 is used to acquire the ship's real-time status information, which includes at least the propeller load torque, methanol engine speed, permanent magnet synchronous motor speed, and the speed difference between the main and driven ends of the clutch.

[0107] The upper-level torque coordination controller 610 is also used to determine whether to trigger a mode switch based on the real-time status information. If so, it generates an upper-level control command based on the real-time status information and the mode switch type. The upper-level control command includes the engine target torque, the motor target torque, and the clutch target torque.

[0108] The upper-level torque coordination controller 610 sends the engine target torque to the engine actuator, the motor target torque to the motor actuator, and the clutch target torque to the lower-level actuator controller.

[0109] The lower-level actuator controller 620 is used to calculate the clutch target oil pressure based on the received clutch target torque through the torque-oil pressure mapping relationship, and calculate the quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component based on the clutch target oil pressure, respectively. The quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component are added together to obtain the drive current of the clutch actuator; and the drive current is output to the clutch actuator.

[0110] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A methanol-electric hybrid ship mode switching dynamic coordination control method, characterized in that, include: S1. Construct a hierarchical coordination control architecture, which includes an upper-level torque coordination controller and a lower-level actuator controller; S2. The upper-level torque coordination controller acquires the ship's real-time status information, which includes at least the propeller load torque, methanol engine speed, permanent magnet synchronous motor speed, and the speed difference between the main and driven ends of the clutch. S3. The upper-level torque coordination controller determines whether to trigger mode switching based on the real-time status information. If so, it generates upper-level control instructions based on the real-time status information and mode switching type. The upper-level control instructions include engine target torque, motor target torque and clutch target torque. S4. The upper-level torque coordination controller sends the engine target torque to the engine actuator, the motor target torque to the motor actuator, and the clutch target torque to the lower-level actuator controller. S5. The lower-level actuator controller calculates the clutch target oil pressure based on the received clutch target torque through the torque-oil pressure mapping relationship, and calculates the quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component based on the clutch target oil pressure. The quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component are added together to obtain the drive current of the clutch actuator; the drive current is then output to the clutch actuator.

2. The method according to claim 1, characterized in that, The methanol-electric hybrid power ship adopts a coaxial parallel hybrid power system; the methanol engine and the permanent magnet synchronous motor are coaxially connected through a wet clutch and jointly drive the propeller. The operating modes of the hybrid power system include pure electric propulsion mode, mechanical propulsion mode, hybrid propulsion mode, and charging propulsion mode; The mode switching includes at least switching between the pure electric propulsion mode and the mechanical propulsion mode, as well as switching between the mechanical propulsion mode and the hybrid propulsion mode.

3. The method of claim 2, wherein, In step S3, the upper-level torque coordination controller determines whether to trigger a mode switch based on the real-time status information, including: When the propeller load torque is greater than a first load threshold and the battery state of charge is lower than a first state of charge threshold, an engine intervention switching is triggered; the engine intervention switching includes switching from the pure electric propulsion mode to the mechanical propulsion mode or the hybrid propulsion mode; When the propeller load torque is less than the second load threshold and the battery state of charge is higher than the second state of charge threshold, an engine exit mode switching is triggered; the engine exit mode switching includes switching from the mechanical propulsion mode or the hybrid propulsion mode to the pure electric propulsion mode. Alternatively, when the speed difference between the driving and driven ends of the clutch is less than the speed difference threshold and the clutch actuator is in a disengaged state, the clutch is triggered to engage in order to switch the operating mode.

4. The method according to claim 1, characterized in that, In step S3, generating the engine target torque specifically includes: An integral sliding surface is constructed using the difference between the desired engine speed and the actual engine speed; Based on the integral sliding surface, the equivalent control terms are calculated using the methanol engine dynamics model. Using the integral sliding surface and its derivative as input, the adaptive switching gain is calculated in real time through fuzzy logic rules; wherein the adaptive switching gain is positively correlated with the absolute value of the integral sliding surface and the absolute value of its derivative. The engine target torque is generated using a control law containing a hyperbolic tangent function, based on the equivalent control term and the adaptive switching gain.

5. The method of claim 1, wherein, The step S3 of generating the target torque of the motor specifically includes: Calculate the motor reference torque based on the propeller load torque and transmission system parameters; Obtain the motor reference torque at the current moment, the motor reference torque at the first historical moment, and the motor reference torque at the second historical moment; Initialize the first scaling factor, the second scaling factor, the first delay time, and the second delay time; and optimize the first scaling factor, the second scaling factor, the first delay time, and the second delay time online by accelerating the particle swarm optimization algorithm with the goal of minimizing the propeller speed deviation. Using the optimized first scaling factor, second scaling factor, first delay time, and second delay time, the motor reference torque at the current moment, the motor reference torque at the first historical moment, and the motor reference torque at the second historical moment are weighted and summed to generate the wave superposition base torque; Calculate the deviation between the desired propeller speed and the actual propeller speed, perform proportional-derivative control on the deviation, and generate feedback compensation torque; The target torque of the motor is obtained by adding the wave superposition base torque to the feedback compensation torque.

6. The method of claim 1, wherein, S3 also includes timing coordination control: Based on the relationship between the speed difference between the clutch driving and driven ends and the preset speed difference threshold, the mode switching process is divided into a preparation stage, a switching stage, and a stabilization stage. During the preparation phase, the permanent magnet synchronous motor is controlled to bear the propeller load torque alone, the methanol engine is controlled to accelerate to be synchronized with the permanent magnet synchronous motor, and the clutch actuator is pre-charged with oil to a low pressure state. During the switching phase, when the speed difference between the driving and driven ends of the clutch is less than the preset speed difference threshold, the oil pressure of the clutch actuator is controlled to rise, the target torque of the engine is controlled to rise linearly, and the target torque of the motor is controlled to fall linearly; wherein, the rate of increase of the target torque of the engine is equal to the rate of decrease of the target torque of the motor, and both the rate of increase and the rate of decrease are less than or equal to the preset maximum rate constraint value. During the stabilization phase, once the clutch actuator is fully engaged, the oil pressure of the clutch actuator is controlled to rise to the rated value, and the sum of the engine target torque and the motor target torque is controlled to equal the propeller load torque.

7. The method of claim 1, wherein, In step S5, the steady-state control current component, the dynamic feedforward compensation current component, and the nonlinear error feedback correction current component are calculated respectively, specifically including: Based on the current-oil pressure steady-state characteristic curve of the solenoid valve and the target oil pressure of the clutch, the quasi-steady-state control current component is calculated; the quasi-steady-state control current component is used to compensate for the steady-state oil pressure demand. The dynamic feedforward compensation current component is calculated based on the rate of change of the target oil pressure of the clutch and the dynamic characteristic coefficient of the hydraulic system; the dynamic feedforward compensation current component is used to compensate for the oil pressure response delay. Based on the deviation between the actual clutch oil pressure and the target clutch oil pressure, an exponential nonlinear feedback law is used to calculate the nonlinear error feedback correction current component; in the exponential nonlinear feedback law, when the absolute value of the deviation increases, the nonlinear error feedback correction current increases exponentially.

8. The method of claim 1, wherein, Also includes: S6. Reacquire the ship's real-time status information; based on the reacquired real-time status information, calculate the engine speed error, motor speed error, and the oil pressure tracking error between the actual clutch oil pressure and the clutch target oil pressure; The engine speed error and the motor speed error are fed back to the upper-level torque coordination controller; the upper-level torque coordination controller updates the engine target torque and motor target torque for the next control cycle based on the engine speed error and the motor speed error; The hydraulic pressure tracking error is fed back to the lower-level actuator controller; the lower-level actuator controller updates the drive current for the next control cycle based on the hydraulic pressure tracking error.

9. The method of claim 8, wherein, It also includes a step to determine if the mode switch is complete: After the closed-loop feedback step, the ship's impact, propeller speed fluctuation, and oil pressure tracking error between the actual clutch oil pressure and the clutch target oil pressure are calculated in real time. When the impact is less than or equal to a preset impact threshold, the propeller speed fluctuation is less than or equal to a preset speed fluctuation threshold, the oil pressure tracking error is less than or equal to a preset oil pressure error threshold, and the clutch actuator is in a fully engaged state, the judgment mode switch is completed. After the determination is completed, maintain the current distribution ratio of engine target torque and motor target torque, and exit the mode switching control process; If the determination is not completed, return to step S2 to continue execution.

10. A methanol-electric hybrid vessel mode switching dynamic coordination control system, characterized by, include: An upper-level torque coordination controller and a lower-level actuator controller are communicatively connected to form a hierarchical coordination control architecture. The upper-level torque coordination controller is used to acquire the ship's real-time status information, which includes at least the propeller load torque, methanol engine speed, permanent magnet synchronous motor speed, and the speed difference between the main and driven ends of the clutch. The upper-level torque coordination controller is also used to determine whether to trigger mode switching based on the real-time status information. If so, it generates upper-level control instructions based on the real-time status information and mode switching type. The upper-level control instructions include engine target torque, motor target torque and clutch target torque. The upper-level torque coordination controller sends the engine target torque to the engine actuator, the motor target torque to the motor actuator, and the clutch target torque to the lower-level actuator controller; The lower-level actuator controller is used to calculate the clutch target oil pressure based on the received clutch target torque through the torque-oil pressure mapping relationship, and calculate the quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component based on the clutch target oil pressure, respectively. The quasi-steady-state control current component, dynamic feedforward compensation current component, and nonlinear error feedback correction current component are added together as the drive current of the clutch actuator. The drive current is output to the clutch actuator.

Images