A variable pitch propeller electric propulsion system cooperative energy efficiency optimization control method

Abstract

The application discloses a variable-pitch propeller electric propulsion system cooperative energy efficiency optimization control method and belongs to the technical field of electric propulsion system control. The method comprises the following steps: acquiring performance data of a variable-pitch propeller and component parameters of a battery, an electric governor and a motor; establishing a unified physical coupling model of the battery, the electric governor, the motor and the propeller based on component models; taking the minimum battery output current as an optimization target, taking physical relations of thrust supply-demand balance, circuit voltage balance and propeller shaft torque balance and variable value boundaries as constraint conditions, and constructing a nonlinear optimization problem; acquiring a flow speed and a required thrust in real time during flight, solving the problem on line by using a nonlinear optimization algorithm, and obtaining optimal propeller pitch angles and throttles; and outputting control instructions to an executing mechanism. The application firstly unifies upstream and downstream physics of an electric propulsion system in a closed nonlinear equation set, and realizes optimal matching of the propulsion system in a full flight envelope.

Description

Technical Field

[0001] This invention belongs to the field of electric propulsion system control technology, specifically relating to a collaborative energy efficiency optimization control method for a variable-pitch propeller electric propulsion system. Background Technology

[0002] A variable-pitch propeller electric propulsion system consists of a battery, electronic speed controller (ESC), motor, propeller, and corresponding pitch control mechanism. Its advantages include the propeller's ability to operate over a wider range of thrust ratios and high overall efficiency across the entire flight envelope. Currently, most engineering projects utilize variable-pitch propellers based on constant-speed variable-pitch control. While this method is simple to implement, it cannot account for the real-time, efficient matching of the drive system and propeller system because the thrust requirements of flight missions change constantly.

[0003] Within normal operating ranges, the efficiency of the motor and ESC remains at a high level. However, during critical conditions such as takeoff, the efficiency of the motor and ESC decreases due to factors such as high load and speed mismatch. The propeller efficiency, on the other hand, varies with the pitch angle and advance ratio. Current research mostly focuses on optimizing individual components for optimal propeller efficiency. The few publicly available methods for integrated optimization of the electric propulsion system lack a unified modeling of the battery-ESC-motor-propeller coupling and are difficult to embed into the control system for real-time control.

[0004] Therefore, there is an urgent need for a method that can unify the physical relationships of electric propulsion systems and achieve real-time collaborative optimization control. Summary of the Invention

[0005] The technical problem to be solved: To overcome the shortcomings of existing technologies, this invention provides a collaborative energy efficiency optimization control method for a variable-pitch propeller electric propulsion system. By constructing component models of the battery, ESC, and motor, as well as a propeller performance model, the upstream and downstream physical relationships of the electric propulsion system are unified. A solution method for the optimal pitch angle and throttle based on nonlinear constraints is established, which can be calculated in real time during flight to achieve online collaborative control of the electric propulsion system, thereby reducing power consumption and improving range.

[0006] The technical solution of this invention is: a method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system, comprising the following steps: Acquire performance data of the variable-pitch propeller and parameters of each component in the electric propulsion system, wherein the electric propulsion system includes at least a battery, an electronic speed controller, a motor, and a variable-pitch propeller; Based on the performance data and the parameters of each component, a unified physical coupling model of the electric propulsion system is constructed. The unified physical coupling model characterizes the physical coupling relationship between the battery, ESC, motor and variable pitch propeller. With minimizing the battery output current as the optimization objective, and taking the physical relationships of thrust supply and demand balance, circuit voltage balance, and propeller shaft torque balance, as well as the boundary values ​​of each variable, as constraints, a nonlinear optimization problem is constructed based on the unified physical coupling model. During flight, the incoming flow velocity and required thrust under the current flight conditions are acquired in real time. The nonlinear optimization problem is solved online using a nonlinear optimization algorithm to obtain the optimal pitch angle and optimal throttle that minimize the battery output current. The optimal pitch angle and optimal throttle are output as control commands to the actuator to control the pitch of the variable pitch propeller and the speed of the motor. A further technical solution of the present invention is: the acquisition of performance data of the variable-pitch propeller specifically includes: The thrust coefficient, torque coefficient, and power coefficient of the variable-pitch propeller under different advance ratios and different pitch angles are obtained; the thrust coefficient C T Torque coefficient C M and power coefficient C p Pre-stored in the form of a two-dimensional data table, arbitrary advance ratios are obtained through two-dimensional interpolation. and pitch angle Corresponding coefficient values ​​under the combination; Based on the thrust coefficient, torque coefficient, and power coefficient, the propulsion performance of a variable-pitch propeller under different operating conditions is calculated, including thrust and torque, as follows:

[0007] in, C T For tensile coefficient, C M For torque coefficient and C p For power coefficient, For the forward ratio, The pitch angle is the propeller angle. The diameter of the variable-pitch propeller. Indicates rotational speed per second. air density, For the incoming flow velocity, For propeller thrust, For propeller torque, For propeller power, For standard speed, For propeller propulsion efficiency.

[0008] A further technical solution of the present invention is: the acquisition of parameters of each component in the electric propulsion system specifically includes: Obtain battery parameters, including cell voltage. and battery internal resistance ; Obtain ESC parameters, including ESC efficiency. ; Obtain motor parameters, including motor specifications. Value, equivalent internal resistance of the motor and rotor viscous friction coefficient motor Equivalent internal resistance and rotor viscous friction coefficient It satisfies the following relationship:

[0009] in, for Standard units are expressed as follows: The back electromotive force coefficient, This is the motor torque coefficient. For load torque, This is the motor terminal current. U m This is to indicate the motor terminal voltage.

[0010] A further technical solution of the present invention is that the terminal voltage and internal current of the battery satisfy a physical relationship based on voltage drop: The terminal voltage of the battery is equal to the cell voltage minus the product of the internal current and the battery's internal resistance, expressed as:

[0011] in, This is the battery's terminal voltage. This refers to the cell voltage of the battery. This refers to the internal current of the battery. This refers to the battery's internal resistance. The efficiency of the battery is the ratio of its output power to its internal power, expressed as:

[0012] A further technical solution of the present invention is: the electronically regulated efficiency The expression is as follows:

[0013] in, These represent the motor terminal voltage and terminal current, respectively.

[0014] A further technical solution of the present invention is: the construction of a unified physical coupling model for an electric propulsion system specifically includes: The component models of the battery, ESC, and motor are associated with the performance model of the variable-pitch propeller. Intermediate variables are eliminated, and a closed nonlinear equation system with throttle, speed, and battery current as unknowns is established. The closed nonlinear equations describe the complete physical coupling relationship of the electric propulsion system under given incoming flow velocity and required thrust conditions. A further technical solution of the present invention is: the expression of the unified physical coupling model of the electric propulsion system is as follows:

[0015] in, For throttle.

[0016] A further technical solution of the present invention is: the nonlinear optimization problem constructed based on the unified physical coupling model specifically includes: Pitch angle, throttle, motor speed and battery current are selected as state variables; The optimization objective function is to minimize the output current of the battery. The electric propulsion system is constrained by the equations of thrust supply and demand balance, circuit voltage balance, and propeller shaft torque balance. Using the physical upper and lower limits of each state variable as inequality constraints, the inequality constraints include at least the pitch angle range constraint, throttle range constraint, motor speed constraint, and positive battery current constraint, expressed as:

[0017] in, x (1) is the propeller pitch angle. β , x (2) Throttle for the propeller , x (3) is the motor speed. , x (4) is the internal current of the battery. , β min This is the lower limit of the usable pitch angle. β max This is the upper limit of the available pitch angle.

[0018] A further technical solution of the present invention is: the online solution of the nonlinear optimization problem using a nonlinear optimization algorithm specifically includes: The inflow velocity and required thrust under the current flight conditions are input into the nonlinear optimization problem as known quantities. The nonlinear optimization problem is solved using a sequential quadratic programming algorithm or an interior point method to obtain the optimal state variable values ​​that minimize the battery output current. Extract the optimal pitch angle and optimal throttle from the optimal state variable values.

[0019] A further technical solution of the present invention is: the step of outputting the optimal pitch angle and optimal throttle as control commands to the actuator specifically includes: The optimal throttle output is sent to the ESC to control the motor speed; The optimal pitch angle is output to the variable pitch actuator to control the pitch of the variable pitch propeller; The above steps are repeated in each control cycle during flight to achieve real-time online collaborative energy efficiency optimization control of the electric propulsion system.

[0020] Beneficial effects The beneficial effects of this invention are as follows: Addressing the shortcomings of existing technologies, such as the lack of unified physical coupling modeling for the battery, ESC, motor, and propeller, and the inability of most methods to achieve real-time online optimization during flight, this invention establishes for the first time a unified closed-loop nonlinear equation model for these four components. With the minimum battery output current as the optimization objective, a nonlinear optimization algorithm is used to solve for the optimal propeller pitch angle and throttle online. This method has a clear physical basis, fewer model parameters, strong transferability, and low computational cost, achieving real-time coordinated energy efficiency optimization of the electric propulsion system within the entire flight envelope, effectively reducing power consumption and improving range. Specific effects are analyzed below: 1. Taking the minimum output current of the electric propulsion system as the optimization objective, a unified coupled model of the battery, ESC, motor and propeller is established, which has a real and clear physical basis; 2. The modeling requires fewer parameters, focusing only on the external characteristic curves of the propeller, and can be directly applied to different propulsion systems; 3. The solution algorithm is simple, requires little code to deploy in hardware, has low requirements for the computing power of the airborne system, and can realize real-time calculation and solution of flight control. 4. It can achieve optimal matching of the propulsion system within the entire flight envelope, effectively reducing battery power consumption and increasing endurance, which has practical significance in engineering practice. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating a collaborative energy efficiency optimization control method for a variable-pitch propeller electric propulsion system according to an embodiment of the present invention. Figure 2 This is a graph showing the thrust performance of the propeller in an embodiment of the present invention; Figure 3 This is a torque performance curve of the propeller in an embodiment of the present invention. Figure 4 This is a graph showing the efficiency performance of the propeller in an embodiment of the present invention. Figure 5 This is a schematic diagram of the optimization verification of working condition one in the embodiments of the present invention; Figure 6This is a schematic diagram of the optimization verification of working condition two in the embodiment of the present invention. Detailed Implementation

[0022] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0023] Current research on energy efficiency optimization of variable-pitch propeller electric propulsion systems, both domestically and internationally, can be mainly categorized as follows: The first category is optimization methods based on the optimal efficiency of a single component. These methods aim to maximize propeller efficiency by adjusting the pitch angle to make the propeller operate at its optimal efficiency point. However, for electric propulsion systems, the overall system efficiency includes not only propeller efficiency but also the efficiency of multiple components such as the electro-mechanical controller (ESC) efficiency and the motor's operating efficiency. Due to the complex coupling relationships between multiple components, the point where the propeller efficiency is maximized does not necessarily mean the overall propulsion system efficiency is maximized.

[0024] The second category is offline optimization methods based on overall system efficiency. For example, the optimal pitch angle CN111216902A is sought by traversing the pitch angles. Although this type of method considers the overall energy consumption of the system, it has the following shortcomings: (1) It treats the efficiency of the motor and controller as constants and ignores their characteristics that change with the operating conditions; (2) It adopts offline traversal solution, which has a large amount of computation and cannot respond to changes in operating conditions in real time during flight; (3) The optimization object is the entire flight mission profile, rather than real-time matching for each flight condition.

[0025] The third category is online control methods based on black-box automatic optimization. For example, CN108791819A. Although this type of method achieves online control, it has the following shortcomings: (1) It adopts a black-box optimization method without a physical model, which lacks clear physical basis and has poor physical interpretability of optimization results; (2) The optimization process depends on continuous disturbance to the system, which may affect flight stability.

[0026] The fourth category is real-time control methods based on efficiency chart lookup tables. For example, US20230122557A1. Although this type of method considers both motor efficiency and propeller efficiency, it is essentially still a data-driven lookup table method rather than a physical model-driven optimization method. It does not establish a unified set of physical equations to describe the coupling relationship between the battery, ESC, motor, and propeller, and the optimization results lack physical consistency.

[0027] Based on the above-mentioned technical problems, this invention proposes a method for optimizing the coordinated energy efficiency of a variable-pitch propeller electric propulsion system, comprising the following steps: Step 1: Obtain propeller performance data Select propeller diameter The performance coefficient of a variable-pitch propeller is the advance ratio. and propeller pitch angle The function includes the propeller thrust coefficient. Torque coefficient and power coefficient The propulsive performance of a propeller can be calculated using the following formula: (1) in, This represents the rotational speed per second (in r / s), satisfying... ; The diameter of the variable-pitch propeller. air density, For the incoming flow velocity, For propeller thrust, For propeller torque, For propeller power, For standard speed, For propeller propulsion efficiency; The tensile coefficient C T Torque coefficient C M and power coefficient C p Pre-stored in the form of a two-dimensional data table, arbitrary advance ratios are obtained through two-dimensional interpolation. and pitch angle The corresponding coefficient values ​​under the combination.

[0028] Step 2: Obtain electric propulsion system parameters The electric propulsion system of this invention consists of a battery, an electronic speed controller, and a motor. The corresponding parameters are obtained based on the models of each component: (1) Battery model parameters: cell voltage of the battery and battery internal resistance It satisfies the following physical relationship based on voltage drop: (2) in: This refers to the internal current of the battery. This is the battery's terminal voltage.

[0029] The battery efficiency is: (3) (2) ESC model parameters: ESC efficiency It satisfies the following relationship: (4) In the formula: These represent the motor terminal voltage and terminal current, respectively. Indicates the throttle opening.

[0030] The efficiency of an electronic speed controller (ESC) based on its input and output is expressed as: (5) (3) Motor model parameters: Motor Equivalent internal resistance The coefficient of viscous friction between the rotor and the rotor It satisfies the following relationship: (6) In the formula: for Standard units are expressed as follows: The back electromotive force coefficient, This is the motor torque coefficient. For load torque, This is the motor terminal current. U m This expression represents the voltage balance of the motor terminals. It reflects the voltage balance of the circuit and the torque balance of the motor in a static state, and is applicable to the steady-state analysis of propulsion systems.

[0031] The motor efficiency is: (7) Step 3: Establish a nonlinear optimization model for the electric propulsion system Based on the component model in step 2, the propeller efficiency, circuit efficiency, and overall efficiency can be expressed as follows: (8) (9) (10) From a macroscopic perspective, the system is at its highest efficiency when the output thrust meets the requirements and the battery output power is at its minimum. Even if the forward speed is zero, as long as the battery output current is at its minimum, it still belongs to the state of minimum energy consumption. To solve for this state, an optimization solution method is constructed.

[0032] By reorganizing the component model described in step 2, eliminating the motor voltage and current, and retaining the throttle, speed, and battery current, we obtain: (11) This set of equations describes the complete physical coupling between the battery, ESC, motor, and propeller. When the pitch angle is selected, it is a closed ternary nonlinear equation set—given the known incoming flow velocity. and demand push At that time, the throttle can be calculated. Rotation speed and battery current Clearly, the overall efficiency of the system varies with different pitch angles, so there must exist a certain pitch angle that maximizes the overall efficiency of the system while meeting the required thrust.

[0033] The state variable is selected as the pitch angle. ,accelerator Motor speed and battery current ,Right now: (12) Based on the three physical relationships of the propulsion system and the theoretical lower and lower limits of each state, the optimization problem is constructed as follows: (13) in, x (1) is the propeller pitch angle. β , x (2) Throttle for the propeller , x (3) is the motor speed. , x (4) is the internal current of the battery. , β min This is the lower limit of the usable pitch angle. β max This is the upper limit of the available pitch angle.

[0034] The equality constraints include physical relationships such as thrust supply and demand balance, circuit voltage balance, and propeller shaft torque balance; the inequality constraints are the boundaries of each variable's value, including: propeller pitch angle range constraints, throttle range constraints, motor speed constraints, and positive battery current constraints.

[0035] Step 4: Solve for the optimal pitch angle and throttle. The optimization problem in step 3 establishes a unified physical coupling relationship between the battery, ESC, motor, and propeller, which is the foundation for the collaborative optimization control achieved in this invention. Various nonlinear optimization algorithms (such as interior-point methods, sequential quadratic programming, or other algorithms) can be used to solve the above model to obtain the pitch angle and throttle with the highest system efficiency.

[0036] Step 5: Output control commands to the actuator During flight, the control system instantly calculates the state of highest efficiency and transmits the target throttle and target pitch angle information to the lower-level actuators, controlling the electronic speed controller and pitch control actuators to complete thrust adjustment.

[0037] The above technical solution will be further explained below with reference to the accompanying drawings and examples: In one embodiment, the specific solution steps are illustrated using a case study of an electric fixed-wing UAV.

[0038] Step (1): Obtain the diameter of the variable-pitch propeller from the propeller manufacturer. and performance data (specifically including tensile strength coefficient) and torque coefficient (Give a two-dimensional data table or according to the forward ratio) and available pitch angle The two-dimensional function representation.

[0039] In this embodiment, the propeller thrust coefficient Torque coefficient and power coefficient C p It is pre-stored in the onboard storage medium in the form of a two-dimensional data table. The row index of the two-dimensional data table is the carry-forward ratio. The column index is the pitch angle. The table stores the corresponding ( , The coefficient values ​​under the combination.

[0040] When replacing propellers of different models, only the corresponding two-dimensional interpolation table file needs to be replaced, without modifying the core code of the optimization algorithm, thus ensuring the portability of the method of this invention between different propulsion systems.

[0041] Figures 2-4 The graphs show the thrust coefficient, torque coefficient, and efficiency of the propeller in this case (which only covers the case with a pitch angle between 15° and 39°) as a function of the pitch angle and the advance ratio. It can be seen that the propeller has better efficiency in the range of large pitch angle and large advance ratio.

[0042] Step (2): Obtain the relevant parameters of the battery, motor, and ESC. The parameters of the electric propulsion system in this case are shown in the table below: Table 2 Main Input Parameters of the Case Power System

[0043] Step (3): Using the data obtained in steps (1) and (2), at a given atmospheric density... Incoming flow velocity and demand push In this case, select the variable: (2) The nonlinear optimization problem is constructed as follows: (2) The equality constraints include three aspects: circuit voltage balance, propeller and motor torque balance, and output thrust equal to demand thrust; the inequality constraints include: pitch angle range constraints (determined by the physically available pitch angle provided by the variable pitch propeller manufacturer), throttle range constraints (generally between 0 and 1, representing from zero throttle to full throttle), motor speed constraints (must be positive and not greater than the upper limit of the motor's theoretical speed), and positive battery current constraints (motor current cannot be less than 0).

[0044] Step (4): Use a nonlinear optimization algorithm to find the optimal solution. Stop when the residual is less than 1e-6 or the number of iterations reaches 10^4.

[0045] For this case, two operating conditions are selected, as shown in the table below: Table 1 Case System Operating Conditions

[0046] This case was solved using a sequential quadratic programming method to obtain the highest efficiency state point for each operating condition. Simultaneously, to verify the correctness of the optimization method, the available pitch angle and throttle combinations that meet the thrust requirements were obtained, and the corresponding propeller efficiency, circuit efficiency, and overall efficiency were calculated and compared in the table below: Table 2 Comparison of Case Optimization Results

[0047] The overall efficiency and component efficiency of the optimal pitch angle state and the remaining pitch angle states traversed are compared (see...). Figures 5-6 This demonstrates the algorithm's effectiveness. Although the circuit efficiency and propeller efficiency in the optimal overall efficiency state may not be the absolute best among all selectable pitch angles, the overall efficiency is optimal, achieving the goal of comprehensive optimization. This also illustrates that when selecting components such as motors and propellers, it is necessary to pay attention to the matching between components.

[0048] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system, characterized in that, Includes the following steps: Acquire performance data of the variable-pitch propeller and parameters of each component in the electric propulsion system, wherein the electric propulsion system includes at least a battery, an electronic speed controller, a motor, and a variable-pitch propeller; Based on the performance data and the parameters of each component, a unified physical coupling model of the electric propulsion system is constructed. The unified physical coupling model characterizes the physical coupling relationship between the battery, ESC, motor and variable pitch propeller. With minimizing the battery output current as the optimization objective, and taking the physical relationships of thrust supply and demand balance, circuit voltage balance, and propeller shaft torque balance, as well as the boundary values ​​of each variable, as constraints, a nonlinear optimization problem is constructed based on the unified physical coupling model. During flight, the incoming flow velocity and required thrust under the current flight conditions are acquired in real time. The nonlinear optimization problem is solved online using a nonlinear optimization algorithm to obtain the optimal pitch angle and optimal throttle that minimize the battery output current. The optimal pitch angle and optimal throttle are output as control commands to the actuator to control the pitch of the variable pitch propeller and the speed of the motor.

2. The method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system according to claim 1, characterized in that: The acquisition of performance data for the variable-pitch propeller specifically includes: The thrust coefficient, torque coefficient, and power coefficient of the variable-pitch propeller under different advance ratios and different pitch angles are obtained; the thrust coefficient, torque coefficient, and power coefficient are pre-stored in the form of a two-dimensional data table, and the corresponding coefficient values ​​under any combination of advance ratio and pitch angle are obtained by two-dimensional interpolation. Based on the thrust coefficient, torque coefficient, and power coefficient, the propulsion performance of a variable-pitch propeller under different operating conditions is calculated, including thrust and torque, as follows: in, C T For tensile coefficient, C M For torque coefficient and C p For power coefficient, For the forward ratio, The pitch angle is the propeller angle. The diameter of the variable-pitch propeller. Indicates rotational speed per second. air density, For the incoming flow velocity, For propeller thrust, For propeller torque, For propeller power, For standard speed, For propeller propulsion efficiency.

3. The method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system according to claim 2, characterized in that: The acquisition of parameters for each component in the electric propulsion system specifically includes: Obtain battery parameters, including cell voltage. and battery internal resistance ; Obtain ESC parameters, including ESC efficiency. ; Obtain motor parameters, including motor specifications. Value, equivalent internal resistance of the motor and rotor viscous friction coefficient motor Equivalent internal resistance and rotor viscous friction coefficient It satisfies the following relationship: in, for Standard units are expressed as follows: The back electromotive force coefficient, This is the motor torque coefficient. For load torque, This is the motor terminal current. U m This indicates the voltage at the motor terminals.

4. The method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system according to claim 3, characterized in that: The battery's terminal voltage and internal current satisfy a physical relationship based on voltage drop: The terminal voltage of the battery is equal to the cell voltage minus the product of the internal current and the battery's internal resistance, expressed as: in, This is the battery's terminal voltage. This refers to the cell voltage of the battery. This refers to the internal current of the battery. This refers to the battery's internal resistance. The efficiency of the battery is the ratio of its output power to its internal power, expressed as: 。 5. The method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system according to claim 4, characterized in that: The electronic control efficiency The expression is as follows: in, These represent the motor terminal voltage and terminal current, respectively.

6. The method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system according to claim 5, characterized in that: The construction of the unified physical coupling model for the electric propulsion system specifically includes: The component models of the battery, ESC, and motor are associated with the performance model of the variable-pitch propeller. Intermediate variables are eliminated, and a closed nonlinear equation system with throttle, speed, and battery current as unknowns is established. The closed nonlinear equations describe the complete physical coupling relationship of the electric propulsion system under given incoming flow velocity and required thrust conditions.

7. The method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system according to claim 6, characterized in that: The expression for the unified physical coupling model of the electric propulsion system is as follows: in, For throttle.

8. The method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system according to claim 7, characterized in that: The nonlinear optimization problem constructed based on the unified physical coupling model specifically includes: Pitch angle, throttle, motor speed and battery current are selected as state variables; The optimization objective function is to minimize the output current of the battery. The electric propulsion system is constrained by the equations of thrust supply and demand balance, circuit voltage balance, and propeller shaft torque balance. Using the physical upper and lower limits of each state variable as inequality constraints, the inequality constraints include at least the pitch angle range constraint, throttle range constraint, motor speed constraint, and positive battery current constraint, expressed as: in, x (1) is the propeller pitch angle. β , x (2) Throttle for the propeller , x (3) is the motor speed. , x (4) is the internal current of the battery. , β min This is the lower limit of the usable pitch angle. β max This is the upper limit of the available pitch angle.

9. The method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system according to claim 8, characterized in that: The online solution of the nonlinear optimization problem using a nonlinear optimization algorithm specifically includes: The inflow velocity and required thrust under the current flight conditions are input into the nonlinear optimization problem as known quantities. The nonlinear optimization problem is solved using a sequential quadratic programming algorithm or an interior point method to obtain the optimal state variable values ​​that minimize the battery output current. Extract the optimal pitch angle and optimal throttle from the optimal state variable values.

10. The method for coordinated energy efficiency optimization control of a variable-pitch propeller electric propulsion system according to claim 9, characterized in that: The step of outputting the optimal pitch angle and optimal throttle as control commands to the actuator specifically includes: The optimal throttle output is sent to the ESC to control the motor speed; The optimal pitch angle is output to the variable pitch actuator to control the pitch of the variable pitch propeller; The above steps are repeated in each control cycle during flight to achieve real-time online collaborative energy efficiency optimization control of the electric propulsion system.

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