Ship electric propulsion control method and device

Abstract

The invention relates to a ship electric propulsion control method and device, designs a novel sliding mode rotating speed loop controller, and compared with a traditional PI rotating speed loop controller, the novel sliding mode rotating speed loop controller has the advantages that overshoot caused by the action of a magnetic field in the starting operation process of a motor is reduced, so that a PMSM has faster time to reach a stable rotating speed in the operation process; meanwhile, in the operation process of the motor, due to the existence of a friction coefficient, a rotating speed ring can generate certain vibration, and compared with a traditional sliding mode controller and a PI controller, the NIA-SMC controller can reduce system vibration, so that the motor can operate more stably. When a load is given to the motor, compared with a PI controller, the NIA-SMC controller has the advantages that the disturbance on a speed ring is smaller, the generated jitter is smaller, and the system recovery time is shorter. And the robustness of the propulsion motor control system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field related to ship electric propulsion, and in particular to a ship electric propulsion control method and device. Background Art

[0002] As a low-emission ship power solution, electric propulsion has become the focus of many research projects due to its advantages such as high maneuverability, high energy utilization efficiency, and low noise.

[0003] There are also many types of propulsion motors, mainly including brushless DC motors, induction motors, permanent magnet synchronous motors (PMSM), high-temperature superconducting motors, etc.

[0004] For PMSM, it is a strong-coupling, non-linear time-varying system inside; traditional control methods include: vector control and direct torque control, etc., and modern control methods include: adaptive control, fuzzy control, neural network control, etc. For traditional vector control, a PI controller is often used to control the speed loop. However, for the complex system of PMSM, it can only ensure the accuracy of control within a certain range. The PI controller highly depends on the accuracy of the complex mathematical model of PMSM. When the internal parameters of PMSM change and it is externally disturbed to a certain extent, the PI controller cannot obtain stable current to make the motor operate in a stable state. Summary of the Invention

[0005] The purpose of the present invention is to at least solve one of the deficiencies of the prior art, and provide a ship electric propulsion control method and device.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: Specifically, a ship electric propulsion control method is proposed, which is applied to PMSM, that is, a permanent magnet synchronous motor, and it is assumed that each phase winding of the PMSM is symmetric, the air gap is uniform, and it is a surface-mounted permanent magnet synchronous motor, including the following: Step 110, establish a parameter equation set of the motor in the rotating coordinate system, and the parameter equation set includes voltage, electromagnetic torque, and mechanical motion equation; Step 120, establish a speed loop mathematical model based on the parameter equation set; Step 130, define a new sliding mode surface function based on the actual speed and reference speed of the motor; Step 140, construct a new sliding mode reaching law based on the adaptive gain coefficient, saturation reaching rate, exponential reaching rate, and new sliding mode surface function; Step 150, construct a new speed loop sliding mode controller based on the new sliding mode reaching law, new sliding mode surface function, and parameter equation set; Step 160: Construct a ship propulsion motor controller based on a novel speed-loop sliding mode controller, and use the ship propulsion motor controller to conduct ship electric propulsion control.

[0007] Furthermore, specifically, establish the parameter equation set of the motor in the rotating coordinate system, including (1); (2); (3); (4); (5); Where: are the d-q axis stator voltage components respectively, i d 、i q are the d-q axis stator current components respectively, is the stator resistance, L d 、L q are the d-q axis stator inductance components respectively; is the stator inductance, are the d-q axis electromagnetic components respectively, is the permanent magnet flux linkage, N is the number of pole pairs of the motor, is the rotor electrical angular velocity, t is the time constant, J is the moment of inertia of the motor, B is the friction coefficient of the motor, are the electromagnetic torque and load torque of the motor respectively.

[0008] Furthermore, specifically, establish the speed-loop mathematical model based on the parameter equation set, including Obtain the mathematical model of the motor under the d-q axis, that is, the speed-loop mathematical model, through the voltage, electromagnetic torque, and mechanical motion equations of the motor: (6).

[0009] Furthermore, specifically, define a novel sliding mode surface function based on the actual speed and reference speed of the motor, including Define the motor system variable : (7); Where: is the reference torque of the motor, is the system variable e the derivative of 1.

[0010] Define the new sliding mode surface function s, that is, the sliding mode error: (8); Where: is the custom parameter of the integral term, is the linear custom parameter, and m represents the sliding mode exponent.

[0011] Furthermore, specifically, based on the adaptive gain coefficient, saturation reaching rate, exponential reaching rate, and new sliding mode surface function, construct a new sliding mode reaching rate, including, Define the new sliding mode reaching rate : (9); Where is the adaptive gain, represents the term proportional to the sliding mode error s, is the exponential reaching rate gain, is the saturation function term, is the saturation reaching rate gain, and is the factor used to adjust the control strength, where is the saturation function threshold, is the base gain, is the adaptive adjustment amplitude, is to adjust the sensitivity of the adaptation to s; And satisfy > 0, > 0, > 0, > 0, > 0, , ; Furthermore, it can be seen from equation (8): (10); It can be seen from equations (6) and (7) that (11); Substitute (11) into equation (10), where let , Get: (12).

[0012] Furthermore, specifically, based on the new sliding mode reaching rate, new sliding mode surface function, and parameter equations, construct a new speed loop sliding mode controller, including, It can be seen from equations (9) and (12) that the new sliding mode controller of the speed loop is designed as: (13) Finally, obtain the q-axis reference current : (14).

[0013] The present invention also provides a ship electric propulsion control device, which applies the ship electric propulsion control method described above, including the following: A parameter equation set establishment module, configured to establish a parameter equation set of the motor in a rotating coordinate system, where the parameter equation set includes voltage, electromagnetic torque, and mechanical motion equations; A rotational speed loop mathematical model establishment module, configured to establish a rotational speed loop mathematical model based on the parameter equation set; A new sliding mode surface function definition module, configured to define a new sliding mode surface function based on the actual rotational speed and the reference rotational speed of the motor; A new sliding mode reaching law construction module, configured to construct a new sliding mode reaching law based on an adaptive gain coefficient, a saturation reaching law, an exponential reaching law, and the new sliding mode surface function; A new rotational speed loop sliding mode controller construction module, configured to construct a new rotational speed loop sliding mode controller based on the new sliding mode reaching law, the new sliding mode surface function, and the parameter equation set; A propulsion control module, configured to construct a ship propulsion motor controller based on the new rotational speed loop sliding mode controller, and perform ship electric propulsion control with the ship propulsion motor controller.

[0014] The beneficial effects of the present invention are as follows: The present invention provides a ship electric propulsion control method and device. First, it replaces the traditional PI controller. Based on the original sliding mode controller theory, it designs a new integral nonlinear sliding mode surface, effectively reducing system chattering and having better robustness to system parameter changes and external disturbances, thereby improving system stability. At the same time, it designs a new saturation exponential reaching law to replace the traditional exponential reaching law and adds an adaptive gain, which can reduce the oscillation near the sliding mode surface while ensuring a good control effect of the sliding mode reaching law. Based on this, the designed new rotational speed loop sliding mode controller constructs a ship propulsion motor controller to perform ship electric propulsion control, which can have the above advantages when performing ship electric propulsion control. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] By describing the embodiments shown in the accompanying drawings in detail, the above and other features of the present disclosure will become more obvious. The same reference numerals in the drawings of the present disclosure represent the same or similar elements. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In the drawings: Figure 1 The flowchart of a ship electric propulsion control method of the present invention is shown. Detailed implementation manners

[0016] The following will clearly and completely describe the concept, specific structure and technical effects generated by the present invention in combination with embodiments and drawings, so as to fully understand the purpose, solution and effects of the present invention. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The same reference numerals used throughout the drawings indicate the same or similar parts.

[0017] Original technology: Adopt Vector control is adopted. Three-phase currents are applied to the stator of the PMSM to output torque. Mathematical modeling of the PMSM is carried out, and the complexity of the system and the control difficulty of the system are reduced through coordinate transformation. There are three coordinate systems for the mathematical modeling of the PMSM: three-phase stationary coordinate system (A - B - C), two-phase stationary coordinate system (α - β), and two-phase rotating coordinate system (d - q).

[0018] Based on the above theoretical basis, the present invention mainly expands based on the PMSM mathematical model in the two-phase rotating coordinate system.

[0019] Embodiment 1, referring to Figure 1 , the present invention proposes a ship electric propulsion control method, which optimizes the speed loop control in the vector control of the PMSM double closed loop (speed loop and current loop), is applied to the PMSM, i.e., the permanent magnet synchronous motor, and assumes that each phase winding of the PMSM is symmetric, the air gap is uniform and it is a surface-mounted permanent magnet synchronous motor, including the following: Step 110: Establish a parameter equation set of the motor in the rotating coordinate system, and the parameter equation set includes voltage, electromagnetic torque, and mechanical motion equation; Step 120: Establish a mathematical model of the speed loop based on the parameter equation set; Step 130: Define a new sliding mode surface function based on the actual speed and reference speed of the motor; Step 140: Construct a new sliding mode reaching law based on the adaptive gain coefficient, saturation reaching rate, exponential reaching rate, and new sliding mode surface function; Step 150: Construct a new speed loop sliding mode controller based on the new sliding mode reaching law, new sliding mode surface function, and parameter equation set; Step 160: Construct a ship propulsion motor controller based on the new speed loop sliding mode controller, and perform ship electric propulsion control with the ship propulsion motor controller.

[0020] In the first embodiment, the traditional PI controller is replaced first. Based on the original sliding mode controller theory, a new integral nonlinear sliding mode surface is designed, which can effectively reduce system chattering and has better robustness to system parameter changes and external disturbances, thus improving the stability of the system. At the same time, a new saturation exponential reaching law is designed to replace the traditional exponential reaching law, and an adaptive gain is added. While ensuring a good control effect of the sliding mode reaching law, it can reduce the oscillation near the sliding mode surface. Based on this, a new rotational speed loop sliding mode controller is designed to construct a ship propulsion motor controller, and ship electric propulsion control is carried out with the above advantages.

[0021] As a preferred embodiment of the present invention, specifically, a parameter equation set of the motor is established in the rotating coordinate system, including, (1); (2); (3); (4); (5); Where: are the stator voltage components on the d-q axes respectively, i d 、i q are the stator current components on the d-q axes respectively, is the stator resistance, L d 、L q are the stator inductance components on the d-q axes respectively; is the stator inductance, are the electromagnetic components on the d-q axes respectively, is the permanent magnet flux linkage, N is the number of pole pairs of the motor, is the rotor electrical angular velocity (obtained by a digital encoder during the real-time operation of the motor), t is the time constant, J is the moment of inertia of the motor, B is the friction coefficient of the motor, are the electromagnetic torque and load torque of the motor respectively.

[0022] As a preferred embodiment of the present invention, specifically, a rotational speed loop mathematical model is established based on the parameter equation set, including, The mathematical model of the motor on the d-q axes, that is, the rotational speed loop mathematical model, is obtained through the voltage, electromagnetic torque, and mechanical motion equations of the motor: (6).

[0023] As a preferred embodiment of the present invention, specifically, a new sliding mode surface function is defined based on the actual speed and reference speed of the motor, including: Define the motor system variables : (7); In the formula: is the motor reference torque (the motor reference torque is determined by the reference speed). is the system variable e The derivative of 1.

[0024] Define the new sliding mode surface function s, that is, the sliding mode error: (8); In the formula: is the self-defined parameter of the integral term, is the self-defined parameter of the linear term.

[0025] In this preferred embodiment, by introducing the integral term, the chattering phenomenon is effectively reduced, the stability of the system is improved. At the same time, by adjusting the linear self-defined parameter, the time for the system to reach the sliding mode surface can be accelerated, achieving the effect of fast response. It can effectively enhance the robustness of the system.

[0026] As a preferred embodiment of the present invention, specifically, a new sliding mode reaching law is constructed based on the adaptive gain coefficient, saturation reaching law, exponential reaching law, and new sliding mode surface function, including: Define the new sliding mode reaching law : (9); In the formula is the adaptive gain, represents the term proportional to the sliding mode error s, is the exponential reaching law gain, used to control the attenuation rate of the system error. Appropriately increasing can accelerate the convergence speed of the system near the sliding mode surface and reduce the oscillation amplitude of the system. It is similar to a linear term. When s is large, the system will quickly tend to the sliding mode surface.

[0027] is the saturation function term. The saturation function sat is used to limit the amplitude of the control input, so that the control of the system can converge smoothly when s approaches the sliding mode surface, and the system will not oscillate due to too large control input. is the saturation reaching law gain. Increasing will accelerate the approaching speed of the system outside the sliding mode surface. Too large will introduce larger chattering, while is a factor used to adjust the control strength, where is the saturation function threshold. Appropriately increasing The value can make the saturation function work in a wider range, reduce jitter and improve stability. But it should be avoided to prevent the system from responding slowly. As the basic gain, adjust the overall approach speed of the system. To adjust the amplitude of the adaptive gain, To adjust the sensitivity of the adaptive to s, the adaptive gain is sensitive to the change of |s|. When |s| is large, the gain is close to , the control gain is larger; when |s| is smaller, the gain decreases, reducing oscillation. When s is larger (far away from the sliding surface), the gain k(s) is larger, allowing the system to converge quickly to the sliding surface. When s is smaller (close to the sliding surface), the gain k(s) decreases, thereby reducing the control strength and reducing oscillation. ( >0, >0, >0, >0, >0, , ).

[0028] The sliding mode approach rate introduces a saturation function sat to replace the traditional exponential approach rate sign function, which can greatly reduce the system's chattering on the sliding mode surface. The exponential part can speed up the system to reach the sliding mode surface.

[0029] A common problem encountered in sliding mode control. Due to the approach rate design, the control signal may produce slight oscillation when approaching the sliding surface. The afterwave of the oscillation is small but lasts for a long time. In order to eliminate the slight oscillation of the system near the sliding surface as much as possible, adding a dynamic adaptive gain k(s) helps to maintain the movement on the sliding surface when the load changes or external disturbances occur, and reduce the chattering phenomenon.

[0030] From formula (8), we can know: (10); From equations (6) and (7), we can see (11); Substitute (11) into (10), where , get: (12).

[0031] As a preferred embodiment of the present invention, specifically, a new speed loop sliding mode controller is constructed based on a new sliding mode approach rate, a new sliding mode surface function and a parameter equation group, including: From equations (9) and (12), we can know that the new sliding mode controller design of the speed loop is: (13); Finally, the q-axis reference current is obtained. : (14).

[0032] In addition, to verify the feasibility of the obtained controller above, the following verification is carried out through the Lyapunov theorem. Take the Lyapunov function as , where V represents the Lyapunov function. If the Lyapunov function can satisfy Equation (15), the stability of the system can be guaranteed. (15); Substitute Equation (9) into Equation (15), and we can get: (16); Expand Equation (16): (17); Analyze Equation (17): When |s| > σ, the saturation function outputs sign(s), and the output has only two values, 1 or -1. Therefore, the reaching law becomes: (18); This expression is strictly negative definite. is a positive number. > 0. Therefore, the system always tends to the sliding surface s = 0, and < 0.

[0033] When |s| ≤ σ, the saturation function = s / σ. Therefore, the reaching law becomes (19); Equation (19) is always less than or equal to 0. Then it satisfies Lyapunov, and the method is feasible.

[0034] The present invention proposes a new sliding mode speed loop controller. Compared with the traditional PI speed loop controller, it reduces the overshoot caused by the magnetic field during the starting and running process of the motor, enabling the PMSM to reach a stable speed faster during operation. At the same time, due to the existence of the friction coefficient during the motor operation, the speed loop will generate certain oscillations. The NIA-SMC controller can reduce the system chattering compared with the traditional sliding mode controller and the PI controller, making the motor run more stably. When a load is applied to the motor, compared with the PI controller, the NIA-SMC controller speed loop is less disturbed, generates less jitter, and the system recovery time is faster. It improves the robustness of the propulsion motor control system.

[0035] The present invention also provides a ship electric propulsion control device, which applies the ship electric propulsion control method described above, including the following: A parameter equation set establishing module, configured to establish a parameter equation set of the motor in a rotating coordinate system, where the parameter equation set includes voltage, electromagnetic torque, and mechanical motion equations; A rotational speed loop mathematical model establishing module, configured to establish a rotational speed loop mathematical model based on the parameter equation set; A new sliding mode surface function defining module, configured to define a new sliding mode surface function based on the actual rotational speed and the reference rotational speed of the motor; A new sliding mode reaching law constructing module, configured to construct a new sliding mode reaching law based on an adaptive gain coefficient, a saturation reaching law, an exponential reaching law, and the new sliding mode surface function; A new rotational speed loop sliding mode controller constructing module, configured to construct a new rotational speed loop sliding mode controller based on the new sliding mode reaching law, the new sliding mode surface function, and the parameter equation set; A propulsion control module, configured to construct a ship propulsion motor controller based on the new rotational speed loop sliding mode controller, and perform ship electric propulsion control with the ship propulsion motor controller.

[0036] In addition, in each embodiment of the present invention, each functional module may be integrated into one processing module, or each module may exist physically alone, or two or more modules may be integrated into one module. The above integrated module may be implemented in the form of hardware or in the form of a software functional module.

[0037] If the above integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may be stored in a computer-readable storage medium. Based on such an understanding, to implement all or part of the processes in the above embodiment methods of the present invention, it may also be completed by a computer program instructing relevant hardware. The computer program may be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above various method embodiments may be implemented. Among them, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium may include: any entity or system, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc., that can carry the computer program code.

[0038] Although the description of the present invention has been quite detailed and several of the described embodiments have been particularly described, it is not intended to be limited to any of these details or embodiments or any particular embodiment, but rather it should be regarded as providing a broad interpretation of these claims in light of the prior art by reference to the appended claims, so as to effectively cover the intended scope of the present invention. In addition, the present invention has been described above in terms of embodiments foreseeable by the inventor for the purpose of providing a useful description, and non-substantive modifications to the present invention that are not currently foreseeable may still represent equivalent modifications of the present invention.

[0039] As described above, these are only the preferred embodiments of the present invention. The present invention is not limited to the above-described embodiments. As long as the same means are used to achieve the technical effects of the present invention, they should fall within the protection scope of the present invention. Within the protection scope of the present invention, various different modifications and variations may be made to its technical solutions and / or embodiments.

Claims

1. A ship electric propulsion control method, characterized in that: Applied to PMSM, i.e. permanent magnet synchronous motor, assuming that the PMSM phase windings are symmetrical, the air gap is uniform, and it is a surface-mounted permanent magnet synchronous motor, including the following: Step 110, establishing a parameter equation group of the motor in a rotating coordinate system, wherein the parameter equation group includes voltage, electromagnetic torque, and mechanical motion equation; Step 120, establishing a speed loop mathematical model based on the parameter equation group; Step 130: defining a new sliding surface function based on the actual speed of the motor and the reference speed; Step 140, constructing a new sliding mode approach rate based on the adaptive gain coefficient, the saturation approach rate, the exponential approach rate, and the new sliding mode surface function; Step 150: construct a new speed loop sliding mode controller based on the new sliding mode approach rate, the new sliding mode surface function and the parameter equation group; Step 160: construct a ship propulsion motor controller based on the novel speed loop sliding mode controller, and use the ship propulsion motor controller to perform ship electric propulsion control; Specifically, Define a new sliding surface function s: ； Defining a new sliding mode approach rate : ； Define a new speed loop sliding mode controller: ； in, , is the motor reference torque, is the motor reference torque, which is an artificially set initial reference value and is a constant; is the derivative of e1, Customize the parameters for the integral term, is a linear custom parameter, m represents the sliding mode index, , B is the friction coefficient of the motor, J is the moment of inertia of the motor, , where is the adaptive gain, represents a term proportional to the sliding mode error s, is the exponential approach rate gain, is the saturation function term, is the saturation approach rate gain, and is a factor used to adjust the control strength, where is the saturation function threshold, is the basic gain, To adjust the amplitude adaptively, To adjust the sensitivity of the adaptation to s, is the rotor electrical angular velocity, is the permanent magnet flux, and N is the number of motor pole pairs.

2. A ship electric propulsion control method according to claim 1, characterized in that: Specifically, the motor parameter equations are established in the rotating coordinate system, including: (1)； (2)； (3)； (4)； (5)； Where: are the dq axis stator voltage components respectively, i d 、i q are the dq axis stator current components, is the stator resistance, L d 、L q are the dq axis stator inductance components respectively; is the stator inductance, are the dq axis electromagnetic components respectively, is the permanent magnet flux, N is the number of motor pole pairs, is the rotor electrical angular velocity, t is the time constant, J is the motor moment of inertia, B is the motor friction coefficient, They are the motor electromagnetic torque and load torque respectively.

3. A ship electric propulsion control method according to claim 2, characterized in that: Specifically, a speed loop mathematical model is established based on the parameter equation group, including: The mathematical model of the motor under the dq axis, that is, the speed loop mathematical model, is obtained through the motor's voltage, electromagnetic torque, and mechanical motion equation: (6)。 4. A ship electric propulsion control method according to claim 3, characterized in that: Specifically, a new sliding surface function is defined based on the actual speed of the motor and the reference speed, including: Define motor system variables : (7)； Where: is the motor reference torque, is the derivative of the system variable e1, Define a new sliding surface function s, that is, the sliding error: (8)； Where: Customize the parameters for the integral term, is a linear custom parameter, and m represents the sliding mode index.

5. A ship electric propulsion control method according to claim 4, characterized in that: Specifically, a new sliding mode approach rate is constructed based on the adaptive gain coefficient, the saturation approach rate, the exponential approach rate, and the new sliding surface function, including: Defining a new sliding mode approach rate : (9)； In the formula is the adaptive gain, represents a term proportional to the sliding mode error s, is the exponential approach rate gain, is the saturation function term, is the saturation approach rate gain, and is a factor used to adjust the control strength, where is the saturation function threshold, is the basic gain, To adjust the amplitude adaptively, To adjust the sensitivity of the adaptation to s; And meet >0, >0, >0, >0, >0, , ; From formula (8), we can know: (10)； From equations (6) and (7), we can see (11)； Substitute (11) into (10), where , get: (12)。 6. A ship electric propulsion control method according to claim 5, characterized in that: Specifically, a new speed loop sliding mode controller is constructed based on a new sliding mode approach rate, a new sliding mode surface function and a set of parameter equations, including: From equations (9) and (12), we can know that the new sliding mode controller design of the speed loop is: (13)； Finally, the q-axis reference current is obtained : (14)。 7. A ship electric propulsion control device, characterized in that: A ship electric propulsion control method according to any one of claims 1 to 6 is applied, comprising the following: A parameter equation group establishment module, used to establish a parameter equation group of the motor in a rotating coordinate system, wherein the parameter equation group includes voltage, electromagnetic torque, and mechanical motion equation; A speed loop mathematical model building module, used to build a speed loop mathematical model based on the parameter equation group; A new sliding surface function definition module is used to define a new sliding surface function based on the actual speed and reference speed of the motor; A new sliding mode approach rate construction module is used to construct a new sliding mode approach rate based on adaptive gain coefficient, saturation approach rate, exponential approach rate, and new sliding mode surface function; A new speed loop sliding mode controller building module is used to build a new speed loop sliding mode controller based on a new sliding mode approach rate, a new sliding mode surface function and a set of parameter equations; The propulsion control module is used to construct a ship propulsion motor controller based on a new speed loop sliding mode controller, and to perform ship electric propulsion control with the ship propulsion motor controller.

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