Electric propulsion ship propulsion motor target rotating speed adaptive control method and system

Abstract

The application discloses a kind of electric propulsion ship propulsion motor target rotating speed self-adapting control method and system.The method includes: collecting driver operation signal and propulsion motor operating parameter;Based on the load torque ratio calculated based on propulsion motor operating parameter;Based on the current navigation working condition identified by preset rule based on driver operation signal and propulsion motor operating parameter;Based on the rotating speed filtering gradient determined by gradient table and correction based on propulsion motor operating parameter, load torque ratio and current navigation working condition;Based on the target rotating speed calculated using incremental filtering algorithm based on rotating speed filtering gradient;When in zero-crossing point switching condition, introduce smoothing factor to correct target rotating speed;Based on the safety target rotating speed obtained by safety limit based on the maximum rotating speed, minimum rotating speed and load torque ratio of propulsion motor;Based on safety target rotating speed control propulsion motor operation.The application can effectively inhibit rotating speed mutation impact and overcurrent fault, improve ship navigation safety and equipment life.

Description

Technical Field

[0001] This invention belongs to the field of ship electric propulsion control technology, and more specifically, relates to an adaptive control method and system for the target speed of the propulsion motor of an electric propulsion ship. Background Technology

[0002] Electric propulsion ships, with their outstanding advantages such as energy saving and environmental protection, flexible maneuverability, high degree of freedom in engine room layout, and good vibration and noise reduction effects, have been widely used in transport ships, engineering operation vessels, and special-purpose vessels. As the core power unit of the entire ship, the propulsion system's control stability of the target speed of the propulsion motor, its timely response, and its load adaptive capability directly determine the ship's navigation safety, maneuverability, and the service life of the propulsion equipment.

[0003] Currently, the speed control of propulsion motors in electric propulsion ships in the industry mostly adopts the traditional fixed-parameter filtering and single-speed deviation closed-loop regulation method. Specifically, the control logic is usually as follows: the driver's handle signal is collected to generate an initial target speed, the deviation between the initial target speed and the actual speed is sent to a PID controller or a simple first-order low-pass filter, and the speed command is output to the frequency converter to drive the motor. This type of control method is simple in logic and easy to implement, but it has the following technical defects in practical applications: (1) Insufficient load adaptability. The existing control only adjusts based on the deviation between the target speed and the actual speed, without introducing load-related parameters such as the actual torque of the motor and the maximum allowable torque for load rate assessment, and cannot detect real-time load changes. When the load fluctuates or the speed deviation is large, the control system blindly increases the motor output power, which can easily cause the propulsion system to work under overload for a long time, accelerating equipment aging or even damage.

[0004] (2) Frequent overcurrent faults. The existing control method lacks a buffer regulation mechanism based on load status. Under conditions of sudden speed changes such as ship starting, acceleration and deceleration, and switching between forward and reverse directions, the inverter output current rises sharply due to sudden changes in control commands, resulting in a large current surge and causing the motor to frequently report overcurrent faults. In severe cases, the motor stops and the propulsion system loses power, posing a major navigation safety hazard.

[0005] (3) Insufficient utilization of torque parameters. Modern frequency converters can generally output parameters such as the actual torque and the maximum allowable torque of the motor in real time, but existing control methods do not construct the torque ratio of "actual torque / maximum allowable torque" as a core control parameter, and cannot quantitatively characterize the real-time load rate and safety margin of the propulsion system. The formulation of control and protection strategies lacks effective load data support.

[0006] (4) The filtering algorithm is imperfect. Existing technologies mostly use low-pass filters with fixed time constants to smooth speed commands. However, fixed-parameter filtering cannot make incremental dynamic adjustments based on the actual current speed of the motor, resulting in problems such as system response lag, large speed overshoot, and poor tracking smoothness. The filtering effect is significantly degraded, especially under conditions of rapid speed changes.

[0007] (5) Incomplete coverage of operating conditions. Ship navigation includes various typical operating conditions such as starting, forward acceleration and deceleration, reverse acceleration and deceleration, and direction switching. Different operating conditions have different requirements for the smoothness and response speed of speed control. Existing control methods use a uniform linear regulation logic and do not classify, identify, or differentiate control for different operating conditions. Under complex sea conditions and reversing conditions, the control effect deteriorates significantly and cannot meet the requirements for stable operation under all operating conditions.

[0008] Therefore, there is an urgent need for a propulsion motor target speed adaptive control method and system that can sense the load status in real time, cover all navigation conditions, and realize dynamic adaptive adjustment of filter parameters, so as to effectively suppress the impact of sudden speed change and overcurrent faults, and improve the safety of ship navigation and equipment life. Summary of the Invention

[0009] The purpose of this invention is to propose an adaptive control method and system for the target speed of the propulsion motor of an electric propulsion ship, which solves the technical problems of insufficient load adaptability, frequent overcurrent faults, lag and overshoot in the filter response, and incomplete coverage of operating conditions in the existing speed control methods for propulsion motors of electric propulsion ships; it effectively suppresses the impact of sudden speed changes and overcurrent faults, thereby improving the safety of ship navigation and the life of equipment.

[0010] To achieve the above objectives, in a first aspect, the present invention proposes an adaptive control method for the target speed of the propulsion motor of an electric propulsion ship, comprising: Collect driver operation signals and propulsion motor operating parameters; Calculate the load torque ratio based on the propulsion motor operating parameters; Based on the driver's operation signals and propulsion motor operating parameters, the current navigation condition is identified through preset rules. The navigation conditions include starting condition, forward acceleration condition, forward deceleration condition, reverse acceleration condition, reverse deceleration condition, and zero-crossing switching condition. Based on the propulsion motor operating parameters, load torque ratio and current navigation conditions, the gradient table is queried and corrected to determine the speed filtering gradient. The target speed is calculated using an incremental filtering algorithm based on the speed filtering gradient; when in the zero-crossing switching condition, a smoothing factor is introduced to correct the target speed. A safe target speed is obtained by applying a safety limit to the target speed based on the maximum speed and minimum speed of the propulsion motor and the load torque ratio. The propulsion motor is controlled based on the target speed for safety.

[0011] Optionally, the driver operation signal includes: The initial target speed of the propulsion motor, forward driving request, reverse driving request, acceleration request, deceleration request, forward / reverse direction switching request, and throttle opening; The operating parameters of the propulsion motor include: the actual speed, actual torque, maximum allowable torque, maximum speed, and minimum speed of the propulsion motor.

[0012] Optionally, the expression for calculating the load torque ratio is: λ=Tq actual / Tq max Among them, Tq actual To increase the actual torque of the motor, Tq max To drive the maximum allowable torque of the motor.

[0013] Optionally, the preset rules include: When the driver operation signal is a request to move forward or reverse, the throttle opening is greater than a preset throttle opening threshold, the initial target speed is greater than the actual speed, and the absolute value of the actual speed is less than a preset speed threshold, it is identified as the starting condition. When the driver operation signal is a forward acceleration request, the throttle opening is greater than a preset throttle opening threshold, the actual speed is greater than zero, the initial target speed is greater than the actual speed, and the absolute value of the actual speed is greater than or equal to a preset speed threshold, it is identified as the positive acceleration condition. When the driver's operation signal is a reversing request, the throttle opening is greater than the preset throttle opening threshold, the actual speed is less than zero, and the absolute value of the initial target speed is greater than the absolute value of the actual speed, it is identified as the reverse acceleration condition. When the driver's operation signal is a request to move forward, the actual speed is greater than zero, and the initial target speed is less than the actual speed, it is identified as the positive deceleration condition. When the driver's operation signal is a reversing request, the actual speed is less than zero, and the absolute value of the initial target speed is less than the absolute value of the actual speed, it is identified as the reverse deceleration condition. When the driver's operation signal is a request to switch between forward and reverse directions, and the actual speed is lower than the zero-crossing speed threshold, it is identified as the zero-crossing switching condition.

[0014] Optionally, determining the speed filtering gradient by querying and correcting the gradient table based on the propulsion motor operating parameters, load torque ratio, and current navigation conditions specifically includes: Calculate the speed deviation based on the initial target speed and the actual speed; Determine the corresponding basic adjustment gradient table based on the current navigation conditions; Using the actual speed and speed deviation as indexes, the basic adjustment gradient corresponding to the current navigation condition is obtained by querying the basic adjustment gradient table; Using the throttle opening and actual speed as indexes, the first correction coefficient is obtained by looking up a table; Using the load torque ratio as an index, the second correction coefficient is obtained by looking up a table; The speed filtering gradient is obtained by multiplying the basic adjustment gradient, the first correction coefficient, and the second correction coefficient.

[0015] Optionally, the target speed is calculated using an incremental filtering algorithm based on the speed filtering gradient; when in a zero-crossing switching condition, a smoothing factor is introduced to correct the target speed, specifically including: Multiply the speed deviation by the speed filtering gradient to obtain the speed increment; The actual rotational speed is added to the rotational speed increment to obtain the target rotational speed under non-zero-crossing switching conditions; When the zero-crossing switching condition is in effect, the smoothing factor is obtained by looking up a table based on the actual speed and speed deviation. Multiply the speed increment by the smoothing factor to obtain the corrected speed increment; The target speed under the zero-crossing switching condition is obtained by adding the actual speed to the corrected speed increment.

[0016] Optionally, the step of applying a safety limit to the target speed based on the maximum speed, minimum speed, and the load torque ratio to obtain a safe target speed specifically includes: Determine whether the target rotational speed exceeds the extreme range of the maximum or minimum rotational speed; if so, clamp the target rotational speed to the corresponding extreme value. Based on the preset range in which the load torque ratio falls, determine the corresponding overload compression ratio; The adjustment amount exceeding the actual speed is compressed using the overload compression ratio to obtain the safe target speed after graded overload limitation.

[0017] Optionally, determining the corresponding overload compression ratio based on the preset range of the load torque ratio specifically includes: When the load torque ratio is less than the first threshold, the overload compression ratio is 1; When the load torque ratio is greater than or equal to the first threshold and less than the second threshold, the overload compression ratio is the first compression value; When the load torque ratio is greater than or equal to the second threshold and less than the third threshold, the overload compression ratio is the second compression value; When the load torque ratio is greater than or equal to the third threshold, the overload compression ratio is the third compression value; The third compression value is less than the second compression value, which is less than the first compression value.

[0018] Optionally, the first threshold is 0.8, the second threshold is 1.0, and the third threshold is 1.1; the first compression value is 0.6, the second compression value is 0.3, and the third compression value is 0.15.

[0019] Secondly, this invention proposes an adaptive control system for the target speed of a propulsion motor in an electric propulsion ship, comprising: Propulsion handle, propulsion remote control unit, propulsion inverter, and propulsion motor; The push handle is used to send driver operation signals; The propulsion remote control unit is electrically connected to both the propulsion handle and the propulsion frequency converter, and is configured as follows: Receives driver operation signals from the propulsion handle and propulsion motor operating parameters fed back by the propulsion inverter; Calculate the load torque ratio based on the propulsion motor operating parameters; Based on the driver's operation signals and propulsion motor operating parameters, the current navigation condition is identified through preset rules. The navigation conditions include starting condition, forward acceleration condition, forward deceleration condition, reverse acceleration condition, reverse deceleration condition, and zero-crossing switching condition. Based on the propulsion motor operating parameters, load torque ratio and current navigation conditions, the gradient table is queried and corrected to determine the speed filtering gradient. The target speed is calculated using an incremental filtering algorithm based on the speed filtering gradient; when in the zero-crossing switching condition, a smoothing factor is introduced to correct the target speed. A safe target speed is obtained by applying a safety limit to the target speed based on the maximum speed and minimum speed of the propulsion motor and the load torque ratio. The propulsion inverter is electrically connected to the propulsion remote control unit and the propulsion motor respectively, and is configured to: receive the safe target speed, generate a PWM drive signal and output it to the propulsion motor; The propulsion motor is electrically connected to the propulsion frequency converter and is configured to operate under the control of the PWM drive signal, and to feed back the current propulsion motor operating parameters to the propulsion frequency converter, and then transmit them back to the propulsion remote control unit to form a closed-loop control.

[0020] The beneficial effects of this invention are as follows: By collecting driver operation signals and propulsion motor operating parameters to calculate the load torque ratio, it provides a quantitative basis for adaptive adjustment based on load perception, avoiding blindly increasing power and causing overload operation; by using preset rules to accurately identify six navigation conditions—starting, forward acceleration / deceleration, reverse acceleration / deceleration, and zero-crossing switching—it achieves full coverage without blind spots and provides a basis for differentiated control; by querying the gradient table and introducing condition-related correction coefficients and torque ratio correction coefficients to determine the speed filtering gradient, it enables different navigation conditions to match differentiated filtering gradient adjustment strategies, significantly improving speed tracking smoothness and response timeliness; by using an incremental filtering algorithm to calculate the target speed and introducing a smoothing factor to correct the target speed in the zero-crossing switching condition, it overcomes the response lag and overshoot problems of traditional fixed-parameter low-pass filtering, achieving dynamic and smooth transition of speed commands; by using a safety limit on the target speed based on the maximum speed, minimum speed, and load torque ratio, it compresses the adjustment amount exceeding the actual speed according to the load torque ratio in stages, achieving graded overload protection.

[0021] In summary, this invention can effectively suppress sudden speed change shocks and instantaneous high currents, eliminate motor overcurrent power loss failures, and significantly improve ship navigation safety, maneuverability, and propulsion equipment service life.

[0022] The system of the present invention has other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0023] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0024] Figure 1 A flowchart illustrating the steps of an adaptive control method for the target speed of a propulsion motor in an electric propulsion ship according to Embodiment 1 of the present invention is shown.

[0025] Figure 2 The basic adjustment gradient lookup table and its three-dimensional mapping relationship diagram under the starting condition according to Embodiment 1 of the present invention are shown.

[0026] Figure 3 The table shows the basic adjustment gradient lookup table and its three-dimensional mapping relationship under the positive acceleration condition according to Embodiment 1 of the present invention.

[0027] Figure 4The table showing the basic adjustment gradient lookup table and its three-dimensional mapping relationship under the reverse acceleration condition according to Embodiment 1 of the present invention is illustrated.

[0028] Figure 5 The basic adjustment gradient lookup table and its three-dimensional mapping relationship diagram under forward / reverse deceleration conditions according to Embodiment 1 of the present invention are shown.

[0029] Figure 6 The first correction coefficient lookup table and its three-dimensional mapping relationship diagram under the starting condition according to Embodiment 1 of the present invention are shown.

[0030] Figure 7 A lookup table of the first correction coefficient under forward / reverse acceleration conditions and its three-dimensional mapping relationship diagram according to Embodiment 1 of the present invention are shown.

[0031] Figure 8 A lookup table of the first correction coefficient under forward / reverse deceleration conditions and its three-dimensional mapping relationship diagram are shown according to Embodiment 1 of the present invention.

[0032] Figure 9 The second correction coefficient lookup table and its two-dimensional mapping relationship diagram according to Embodiment 1 of the present invention are shown.

[0033] Figure 10 A smoothing factor lookup table and its three-dimensional mapping relationship diagram according to Embodiment 1 of the present invention are shown.

[0034] Figure 11 A schematic diagram of an adaptive control system for the target speed of a propulsion motor in an electric propulsion ship according to Embodiment 2 of the present invention is shown. Detailed Implementation

[0035] The invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0036] Example 1

[0037] like Figure 1 As shown, this embodiment provides an adaptive control method for the target speed of the propulsion motor of an electric propulsion ship, including: S1. Collect driver operation signals and propulsion motor operating parameters; In this step, the driver's operation signals include: The initial target speed of the propulsion motor, forward driving request, reverse driving request, acceleration request, deceleration request, forward / reverse direction switching request, and throttle opening; The operating parameters of the propulsion motor include: the actual speed, actual torque, maximum allowable torque, maximum speed, and minimum speed of the propulsion motor.

[0038] Specifically, in the adaptive control of the propulsion motor's target speed, it is first necessary to collect the command signals from the operator's control terminal and the operating status parameters of the propulsion motor itself in real time. The operator's control signals include: the initial target speed input from the propulsion handle position or remote control panel, which represents the motor speed that the operator expects to achieve; forward and reverse requests, which indicate the ship's forward or reverse direction; acceleration and deceleration requests, which express the operator's intention to control the speed increase or decrease; forward / reverse direction switching requests, which identify whether the operator is performing a reversing operation between forward and reverse; and throttle opening signals, which reflect the operator's demand for power output, usually expressed as a percentage.

[0039] Simultaneously, the system also collects status parameters fed back by the propulsion motor during operation, including: the actual speed of the motor, i.e., the real speed value of the motor rotor at the current moment, the positive and negative values ​​are used to determine the rotation direction of the motor (positive value is forward rotation, negative value is reverse rotation); the actual torque of the motor, representing the electromagnetic torque currently output by the motor; the maximum allowable torque of the motor, which is the instantaneous maximum output torque calculated in real time by the frequency converter or motor controller based on the motor's thermal capacity, current limit, etc., and is a key boundary value for judging the motor's overload capacity; in addition, the maximum and minimum allowable speeds of the motor also need to be obtained as the upper and lower boundaries of subsequent safety limits.

[0040] The accurate acquisition of the aforementioned driver operation signals and motor operating parameters provides a complete data foundation for subsequent load torque ratio calculation, navigation condition identification, filter gradient adjustment, and safety limits.

[0041] S2. Calculate the load torque ratio based on the propulsion motor operating parameters; In this step, the expression for calculating the load torque ratio is: λ= Tq actual / Tq max Among them, Tq actual To increase the actual torque of the motor, Tq max To drive the maximum allowable torque of the motor.

[0042] Specifically, after collecting the operating parameters of the propulsion motor, the system calculates the load torque ratio based on the following expression: λ = Tq actual / Tq max Tq actual To increase the actual torque of the motor, Tq maxThis ratio λ represents the maximum allowable torque for the propulsion motor. It is a dimensionless parameter that characterizes the current load rate of the propulsion motor and its margin relative to the safe operating boundary in real time. When λ approaches or exceeds 1.0, it indicates that the motor is under full load or even overload; when λ is much less than 1.0, it indicates a light load. Compared to traditional control strategies that rely solely on speed deviation, introducing the load torque ratio λ as a core control parameter allows the control system to quantitatively perceive the instantaneous load status of the propulsion system. This provides scientific data for subsequent gradient adjustment, overload protection, and safety limits, avoiding blindly increasing speed commands under heavy load conditions, which could lead to current surges or overcurrent faults.

[0043] S3. Based on the driver's operation signal and the propulsion motor operating parameters, the current navigation condition is identified through preset rules. The navigation conditions include starting condition, forward acceleration condition, forward deceleration condition, reverse acceleration condition, reverse deceleration condition and zero crossing switching condition. In this step, the preset rules include: When the driver's operation signal is a request to move forward or reverse, the throttle opening is greater than the preset throttle opening threshold, the initial target speed is greater than the actual speed, and the absolute value of the actual speed is less than the preset speed threshold, it is identified as a starting condition. When the driver's operation signal is a request for forward acceleration, the throttle opening is greater than the preset throttle opening threshold, the actual speed is greater than zero, the initial target speed is greater than the actual speed, and the absolute value of the actual speed is greater than or equal to the preset speed threshold, it is identified as a positive acceleration condition. When the driver's operation signal is a reversing request, the throttle opening is greater than the preset throttle opening threshold, the actual speed is less than zero, and the absolute value of the initial target speed is greater than the absolute value of the actual speed, it is identified as a reverse acceleration condition. When the driver's operation signal is a request for forward movement, the actual speed is greater than zero, and the initial target speed is less than the actual speed, it is identified as a positive deceleration condition. When the driver's operation signal is a reversing request, the actual speed is less than zero, and the absolute value of the initial target speed is less than the absolute value of the actual speed, it is identified as a reverse deceleration condition. When the driver's operation signal is a request to switch between forward and reverse directions, and the actual speed is lower than the zero-crossing speed threshold, it is identified as a zero-crossing switching condition.

[0044] Specifically, when identifying the current navigation condition based on the pilot's operation signals and propulsion motor operating parameters, the system uses the following preset rules to accurately determine six typical operating conditions: Starting condition: When the driver's operation signal is a forward or reverse request, the throttle opening is greater than the preset throttle opening threshold (e.g., 5%), the initial target speed is greater than the actual speed, and the absolute value of the actual speed is less than the preset speed threshold (e.g., 100 rpm), it indicates that the ship is in a stationary starting state, and the system recognizes it as a starting condition.

[0045] Forward acceleration condition: When the driver's operation signal is a forward vehicle request, the throttle opening is greater than the preset throttle opening threshold, the actual speed is greater than zero (indicating that the motor is rotating in the forward direction), the initial target speed is greater than the actual speed, and the absolute value of the actual speed is greater than or equal to the preset speed threshold, the system recognizes it as a forward acceleration condition.

[0046] Reverse acceleration condition: When the driver's operation signal is a reversing request, the throttle opening is greater than the preset throttle opening threshold, the actual speed is less than zero (indicating that the motor has rotated in reverse), and the absolute value of the initial target speed is greater than the absolute value of the actual speed, the system recognizes it as a reverse acceleration condition.

[0047] Positive deceleration condition: When the driver's operation signal is a request to move forward, the actual speed is greater than zero, and the initial target speed is less than the actual speed, it indicates that the driver is reducing the throttle or instructing the driver to slow down, and the system recognizes it as a positive deceleration condition.

[0048] Reverse deceleration condition: When the driver's operation signal is a reversing request, the actual speed is less than zero, and the absolute value of the initial target speed is less than the absolute value of the actual speed, the system recognizes it as a reverse deceleration condition.

[0049] Zero-crossing switching condition: When the driver's operation signal is a request to switch between forward and reverse directions (e.g., switching directly from forward to reverse, or switching from reverse to forward), and the absolute value of the motor's actual speed is lower than the preset zero-crossing speed threshold (e.g., 10 rpm or 20 rpm), the system recognizes it as a zero-crossing switching condition. At this time, the motor speed is about to cross zero and enter reverse rotation, which requires special smoothing processing.

[0050] The aforementioned preset rules fully consider key information such as throttle opening, actual speed direction, comparison between target and actual speed, and direction switching requests. They can accurately distinguish all typical operating conditions that a ship may encounter during navigation, providing a reliable basis for subsequent differentiated gradient adjustments. Among them, the preset throttle opening threshold, preset speed threshold, and zero-crossing speed threshold can all be calibrated and adjusted according to the specific ship type, motor characteristics, and sea state.

[0051] S4. Based on the propulsion motor operating parameters, load torque ratio and current navigation conditions, query the gradient table and make corrections to determine the speed filtering gradient; In this step, based on the propulsion motor operating parameters, load torque ratio, and current navigation conditions, the gradient table is queried and corrected to determine the speed filtering gradient, specifically including: Calculate the speed deviation based on the initial target speed and the actual speed; Determine the corresponding basic adjustment gradient table based on the current navigation conditions; Using the actual speed and speed deviation as indexes, query the basic adjustment gradient table to obtain the basic adjustment gradient corresponding to the current navigation condition; Using throttle opening and actual engine speed as indexes, the first correction factor is obtained by looking up a table. The second correction factor is obtained by looking up a table using the load torque ratio as an index. Multiply the base adjustment gradient, the first correction coefficient, and the second correction coefficient to obtain the speed filtering gradient.

[0052] Specifically, in determining the speed filtering gradient, the system first uses the acquired initial target speed n target and the actual speed n of the motor actual Calculate the speed deviation Δn=n target -n actual This deviation reflects the difference between the current speed command and the actual speed, and serves as the basic input for subsequent gradient adjustments. Subsequently, based on the current navigation condition (starting, forward acceleration, forward deceleration, reverse acceleration, reverse deceleration, or zero-crossing switching) identified in step S3, the system selects the basic adjustment gradient table corresponding to that condition.

[0053] Figure 2 The basic adjustment gradient lookup table and its three-dimensional mapping relationship diagram under the starting condition are shown, as follows: Figure 2 As shown, under starting conditions, the basic adjustment gradient table is a two-dimensional lookup table. The horizontal axis (the second row of the table) represents the segmented boundary values ​​of the speed deviation Δn, which are: -80 rpm, 0 rpm, 100 rpm, 200 rpm, 300 rpm, 500 rpm, 1000 rpm, and 1200 rpm. The vertical axis (the second column of the table) represents the segmented boundary values ​​of the actual motor speed n_actual, which are: 10 rpm, 100 rpm, 200 rpm, 300 rpm, 500 rpm, 1000 rpm, and 1200 rpm. The remaining cells in the table contain the specific values ​​of the basic adjustment gradient Gbase. These values ​​can be calibrated offline based on the ship type, motor characteristics, and sea conditions.

[0054] Figure 3 The table showing the basic adjustment gradient lookup table and its three-dimensional mapping relationship under positive acceleration conditions is illustrated. Figure 3As shown, under positive acceleration conditions, the base adjustment gradient table is a two-dimensional lookup table. The horizontal axis (the second row of the table) represents the segmented boundary values ​​of the speed deviation Δn, which are: -20 rpm, 0 rpm, 20 rpm, 40 rpm, 100 rpm, 600 rpm, 1000 rpm, 1500 rpm, 2000 rpm, and 2500 rpm. The vertical axis (the second column of the table) represents the segmented boundary values ​​of the actual motor speed n_actual, which are 100 rpm, 500 rpm, and 1000 rpm. The remaining cells in the table contain the specific values ​​of the base adjustment gradient Gbase. These values ​​can be calibrated offline based on the ship type, motor characteristics, and sea conditions.

[0055] Figure 4 The basic adjustment gradient lookup table and its three-dimensional mapping relationship diagram under the reverse acceleration condition are shown, as follows: Figure 4 As shown, under reverse acceleration conditions, the base adjustment gradient table is a two-dimensional lookup table. Its horizontal axis (the second row of the table) represents the segmented boundary values ​​of the speed deviation Δn, which are: -20 rpm, 0 rpm, 20 rpm, 40 rpm, 100 rpm, 600 rpm, 1000 rpm, 1500 rpm, 2000 rpm, and 2500 rpm. Its vertical axis (the second column of the table) represents the segmented boundary values ​​of the actual motor speed n_actual, which are: -2000 rpm, -1000 rpm, -500 rpm, and 0 rpm (negative values ​​indicate reverse rotation). The remaining cells in the table contain the specific values ​​of the base adjustment gradient Gbase. These values ​​can be calibrated offline based on the ship type, motor characteristics, and sea conditions.

[0056] Figure 5 The basic adjustment gradient lookup table and its three-dimensional mapping relationship diagram under forward / reverse deceleration conditions are shown, as follows: Figure 5 As shown, under forward / reverse deceleration conditions, the basic adjustment gradient table is a two-dimensional lookup table. The horizontal axis (the second row of the table) represents the segmented boundary values ​​of the speed deviation Δn, which are: -20rpm, 0rpm, 200rpm, 400rpm, 1000rpm, 1200rpm, 1500rpm, and 2000rpm (negative values ​​indicate that the target speed is less than the actual speed, corresponding to deceleration requirements). The vertical axis (the second column of the table) represents the segmented boundary values ​​of the actual motor speed n_actual, which are: 0rpm, 400rpm, 600rpm, 800rpm, 900rpm, 1200rpm, 1400rpm, 1600rpm, 1800rpm, 2000rpm, 2200rpm, 2400rpm, and 2600rpm. The remaining cells in the table contain the specific values ​​of the basic adjustment gradient Gbase, all of which are negative, representing the adjustment amount in the deceleration direction.

[0057] After obtaining the basic adjustment gradient, the system further introduces two correction coefficients to enhance the adaptability to operating conditions and loads. The first correction coefficient K1 is obtained by looking up a table based on the throttle opening and actual speed: for positive acceleration conditions, the larger the throttle opening and the higher the actual speed, the larger the value of K1 is usually, in order to speed up the response; for positive deceleration conditions, the adjustment trend of K1 is opposite, in order to achieve smooth deceleration.

[0058] Figure 6 The table showing the first correction coefficient lookup table and its three-dimensional mapping relationship under the starting condition is illustrated, as follows: Figure 6 As shown, under starting conditions, the first correction coefficient table is a two-dimensional lookup table. The horizontal axis (the second row of the table) represents the segmented boundary values ​​of the throttle opening, which are: 0%, 5%, 10%, 20%, 30%, 50%, and 80%. The vertical axis (the second column of the table) represents the segmented boundary values ​​of the actual motor speed n_actual, which are: 0 rpm, 400 rpm, 600 rpm, 800 rpm, 900 rpm, 1200 rpm, 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2400 rpm, and 2600 rpm. The remaining cells in the table represent the specific values ​​of the first correction coefficient K1. The specific values ​​in the table can be calibrated offline according to the ship type, motor characteristics, and sea state.

[0059] Figure 7 The table showing the first correction coefficient lookup table and its three-dimensional mapping relationship under forward / reverse acceleration conditions is illustrated. Figure 7 As shown, under forward / reverse acceleration conditions, the first correction coefficient table is a two-dimensional lookup table. The horizontal axis (the second row of the table) represents the segmented boundary values ​​of the throttle opening, which are: 0%, 5%, 10%, 20%, 30%, 50%, and 80%. The vertical axis (the second column of the table) represents the segmented boundary values ​​of the actual motor speed n_actual, which are: 0 rpm, 400 rpm, 600 rpm, 800 rpm, 900 rpm, 1200 rpm, 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2400 rpm, and 2600 rpm. The remaining cells in the table represent the specific values ​​of the first correction coefficient K1. The specific values ​​in the table can be calibrated offline according to the ship type, motor characteristics, and sea state.

[0060] Figure 8 The table showing the first correction coefficient lookup table and its three-dimensional mapping relationship under forward / reverse deceleration conditions is illustrated. Figure 8As shown, under forward / reverse deceleration conditions, the first correction coefficient table is a two-dimensional lookup table. The horizontal axis (the second row of the table) represents the segmented boundary values ​​of the throttle opening, which are 30%, 50%, 80%, and 100% respectively. The vertical axis (the second column of the table) represents the segmented boundary values ​​of the actual motor speed n_actual, which are 0 rpm, 400 rpm, 600 rpm, 800 rpm, 900 rpm, 1200 rpm, 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2400 rpm, and 2600 rpm respectively. The remaining cells in the table represent the specific values ​​of the first correction coefficient K1. The specific values ​​in the table can be calibrated offline according to the ship type, motor characteristics, and sea state.

[0061] The second correction factor K2(λ) is based on the load torque ratio λ=Tq. actual / Tq max Obtained by looking up the table using an index. Figure 9 The second correction coefficient lookup table and its two-dimensional mapping relationship diagram are shown, as follows: Figure 9 The table shown is a two-dimensional lookup table for the second correction coefficient K2(λ). The second column represents the load torque ratio λ, and the third column represents the second correction coefficient K2. A larger λ indicates a heavier load, and a smaller K2(λ) value is obtained. This automatically reduces the filter gradient under high loads, preventing current surges caused by excessive speed regulation. Typically, K2 approaches 1.0 when λ < 0.5, and can drop below 0.25 when λ > 1.0. Specific values ​​in the table can be calibrated offline based on ship type, motor characteristics, and sea conditions.

[0062] Finally, the system multiplies the base adjustment gradient Gbase, the first correction coefficient K1, and the second correction coefficient K2(λ) to calculate the speed filtering gradient Gzc = Gbase × K1 × K2(λ). This gradient is a dimensionless coefficient between 0 and 1, determining the proportion of speed deviation responded to in a single adjustment cycle. Through the above step-by-step lookup and correction, the speed filtering gradient can dynamically and adaptively adjust according to navigation conditions, load changes, and pilot operation intensity, providing a precise adjustment step size for subsequent incremental filtering.

[0063] S5. The target speed is calculated using an incremental filtering algorithm based on the speed filtering gradient; when in the zero-crossing switching condition, a smoothing factor is introduced to correct the target speed. In this step, the target speed is calculated using an incremental filtering algorithm based on the speed filtering gradient; when in a zero-crossing switching condition, a smoothing factor is introduced to correct the target speed, specifically including: Multiply the speed deviation by the speed filtering gradient to obtain the speed increment; Add the actual speed to the speed increment to obtain the target speed under non-zero-crossing switching conditions; When in the zero-crossing switching condition, the smoothing factor is obtained by looking up a table based on the actual speed and speed deviation. Multiply the speed increment by the smoothing factor to obtain the corrected speed increment; The target speed under the zero-crossing switching condition is obtained by adding the actual speed to the corrected speed increment.

[0064] Specifically, after determining the speed filtering gradient, the system uses an incremental filtering algorithm to calculate the target speed.

[0065] First, multiply the speed deviation Δn calculated in step S4 by the speed filtering gradient Gzc to obtain the speed increment Δn for this adjustment cycle. inc =Gzc×Δn.

[0066] Then, the actual speed n of the current motor is... actual Adding this speed increment to the target speed under non-zero-crossing switching conditions yields n. ref,filter =n actual +Δn inc .

[0067] When the system detects that it is currently in a zero-crossing switching condition, a smoothing factor needs to be introduced to correct the speed increment in order to suppress the impact at the moment of zero-crossing. The system adjusts the speed based on the current actual motor speed n. actual Using the speed deviation Δn as a two-dimensional index, the preset smoothing factor table is queried to obtain the smoothing factor. factor (Its value usually ranges from 0 to 1, and the closer the absolute value of the actual rotational speed is to zero, the smoother it becomes.) factor The smaller the value.

[0068] Figure 10 The smoothing factor lookup table and its three-dimensional mapping relationship diagram are shown, such as Figure 10 As shown, the smoothing factor table is a two-dimensional lookup table. The horizontal axis (the second row of the table) represents the segmented boundary values ​​of the speed deviation Δn, which are: -300 rpm, -200 rpm, -100 rpm, 0 rpm, 100 rpm, 200 rpm, and 300 rpm. The vertical axis (the second column of the table) represents the actual motor speed n. actualThe table provides segmented boundary values: -50 rpm, 0 rpm, 50 rpm, and 100 rpm (negative values ​​indicate reverse rotation). The remaining cells in the table represent the corresponding smoothing factor values. The physical meaning of this table is: the closer the motor speed is to zero, the smaller the adjustment range (smaller smoothing factor) should be during zero-crossing switching to ensure a smooth transition; conversely, when the speed is far from zero, a larger adjustment range is permissible. The specific values ​​in the table can be calibrated offline based on the ship type and motor characteristics. During querying, the system finds the corresponding smoothing factor in the table based on the current actual speed and speed deviation, which is used to correct the speed increment, thereby achieving smooth control under zero-crossing conditions.

[0069] Then the original speed increment Δn inc Multiplying by this smoothing factor yields the corrected speed increment Δn. corr =Δn inc ×smooth factor Finally, the current actual rotational speed n actual With the corrected speed increment Δn corr Adding them together, we obtain the target speed under the zero-crossing switching condition, i.e., n. ref,filter =n actual +Δn corr .

[0070] Through the above processing, standard incremental filtering is used to ensure timely response under normal operating conditions, while the adjustment step size is flexibly reduced by a smoothing factor under zero-crossing switching conditions, thereby achieving a smooth transition of speed commands and effectively avoiding current spikes when the motor crosses zero.

[0071] S6. Based on the maximum speed, minimum speed and load torque ratio of the propulsion motor, a safe target speed is obtained by setting a safety limit on the target speed. In this step, a safe target speed is obtained by applying a safety limit to the target speed based on the maximum speed, minimum speed, and load torque ratio. Specifically, this includes: Determine whether the target speed exceeds the extreme range of the maximum or minimum speed. If so, clamp the target speed to the corresponding extreme value. Determine the corresponding overload compression ratio based on the preset range in which the load torque ratio falls; By using the overload compression ratio to compress the adjustment amount exceeding the actual speed, a safe target speed after graded overload limitation is obtained.

[0072] Specifically, after obtaining the filtered target speed, the system further applies dual safety limits to the target speed to generate the final safe target speed.

[0073] First, extreme value clamping limitation is executed: it is determined whether the target speed after filtering exceeds the maximum or minimum speed range allowed by the propulsion motor. If it does, the target speed is forcibly limited to the corresponding extreme value (i.e., clamped to the maximum or minimum speed) to ensure that the speed command is always within the safe operating range of the motor.

[0074] Subsequently, graded overload limiting is implemented based on the load torque ratio λ to suppress speed regulation under heavy load conditions. The system determines the corresponding overload compression ratio (i.e., the percentage of adjustment retained) based on the preset range in which the current load torque ratio λ falls: When λ is less than the first threshold (e.g., 0.8), the compression ratio is 1, which means no attenuation is performed. When λ is greater than or equal to the first threshold and less than the second threshold (e.g., 1.0), the compression ratio is the first compression value (e.g., 0.6), retaining only 60% of the adjustment amount; When λ is greater than or equal to the second threshold and less than the third threshold (e.g., 1.1), the compression ratio is the second compression value (e.g., 0.3), and only 30% of the adjustment amount is retained; When λ is greater than or equal to the third threshold, the compression ratio is the third compression value (e.g., 0.15), retaining only 15% of the adjustment amount.

[0075] The overload compression ratio is used to compress the adjustment amount exceeding the actual speed (i.e., the difference between the filtered target speed and the actual speed), resulting in a safe target speed after graded overload limiting. The calculation method is: Safe target speed = Actual speed + Overload compression ratio × (Filtered target speed - Actual speed).

[0076] Through the dual safety limitations of extreme clamping and graded overload compression, the speed command is ensured not to exceed the mechanical and electrical limits of the motor, while the speed regulation range is significantly reduced under high load or overload conditions, thus preventing current surges and overcurrent faults from the source and improving the safety of system operation.

[0077] In this step, the corresponding overload compression ratio is determined based on the preset range of the load torque ratio, specifically including: When the load torque ratio is less than the first threshold, the overload compression ratio is 1. When the load torque ratio is greater than or equal to the first threshold and less than the second threshold, the overload compression ratio is the first compression value. When the load torque ratio is greater than or equal to the second threshold and less than the third threshold, the overload compression ratio is the second compression value. When the load torque ratio is greater than or equal to the third threshold, the overload compression ratio is the third compression value; Among them, the third compression value is less than the second compression value, which is less than the first compression value.

[0078] In this step, the first threshold is 0.8, the second threshold is 1.0, and the third threshold is 1.1; the first compression value is 0.6, the second compression value is 0.3, and the third compression value is 0.15.

[0079] S7. Drive motor operation based on safe target speed control.

[0080] Specifically, after meeting safety limits and obtaining the target speed, the system outputs this speed command as the final speed setpoint to the propulsion inverter MCU. Upon receiving the target speed, the propulsion inverter generates a corresponding PWM (Pulse Width Modulation) drive signal based on its internal vector control or direct torque control algorithm, driving the propulsion motor to operate at the target speed. Simultaneously, the propulsion inverter collects real-time operating parameters such as the motor's actual speed, actual torque, and maximum allowable torque, feeding these parameters back to the propulsion remote control unit (PCS), forming a complete closed-loop control. The PCS continuously monitors the tracking error between the motor's actual speed and the target speed, as well as the dynamic changes in the load torque ratio, optimizing the parameters in the gradient lookup table online, and implementing fault diagnosis and graded overload warning protection. Through this closed-loop control, the propulsion motor can smoothly and accurately follow the pilot's speed commands under different navigation conditions and loads, effectively suppressing sudden speed changes, preventing power loss due to overload, and ensuring ship navigation safety.

[0081] Example 2

[0082] like Figure 11 As shown, this embodiment provides an adaptive control system for the target speed of the propulsion motor of an electric propulsion ship, including: Propulsion handle, propulsion remote control unit, propulsion inverter, and propulsion motor; The push handle is used to send driver operation signals; The propulsion remote control unit is electrically connected to both the propulsion handle and the propulsion inverter, and is configured as follows: It receives driver operation signals from the propulsion handle and propulsion motor operating parameters fed back from the propulsion frequency converter; Calculate the load torque ratio based on the propulsion motor operating parameters; Based on the driver's operation signals and the propulsion motor's operating parameters, the current navigation condition is identified through preset rules. The navigation conditions include starting condition, forward acceleration condition, forward deceleration condition, reverse acceleration condition, reverse deceleration condition, and zero-crossing switching condition. Based on the propulsion motor operating parameters, load torque ratio and current navigation conditions, the gradient table is queried and corrected to determine the speed filtering gradient. The target speed is calculated using an incremental filtering algorithm based on the speed filtering gradient; when the zero-crossing switching condition is in progress, a smoothing factor is introduced to correct the target speed. A safe target speed is obtained by applying a safety limit to the target speed based on the maximum speed, minimum speed and load torque ratio of the propulsion motor; The propulsion inverter is electrically connected to the propulsion remote control unit and the propulsion motor respectively. It is configured to receive a safe target speed, generate a PWM drive signal and output it to the propulsion motor. The propulsion motor is electrically connected to the propulsion frequency converter and is configured to operate under the control of the PWM drive signal, and to feed back the current operating parameters of the propulsion motor to the propulsion frequency converter, and then transmit them back to the propulsion remote control unit to form a closed-loop control.

[0083] Specifically, the adaptive control system for the target speed of the propulsion motor of an electric propulsion ship provided in this embodiment mainly consists of four core components: a propulsion handle, a propulsion remote control unit, a propulsion frequency converter, and a propulsion motor. The propulsion handle is responsible for issuing driver operation signals, including commands such as forward movement requests, reverse movement requests, acceleration requests, deceleration requests, forward / reverse direction switching requests, and throttle opening.

[0084] The propulsion remote control unit is electrically connected to the propulsion handle and the propulsion frequency converter. It integrates a propulsion remote control module, a working condition identification module, a torque ratio calculation module, a gradient query and correction module, an incremental filter calculation module, and a safety monitoring and limiting module to execute a complete adaptive control algorithm.

[0085] First, the remote control module receives the driver's operation signal from the propulsion handle, and at the same time, the propulsion inverter feeds back the operating parameters of the propulsion motor, such as the actual speed, actual torque, maximum allowable torque, maximum speed, and minimum speed.

[0086] The torque ratio calculation module calculates the load torque ratio λ=Tq_actual / Tq_max based on the ratio of the actual torque to the maximum allowable torque, which serves as the core parameter for quantifying the load rate.

[0087] The operating condition identification module accurately identifies the current navigation conditions of the ship based on preset rules (such as throttle opening threshold, speed threshold, comparison between target speed and actual speed, and direction switching request), including starting conditions, forward acceleration conditions, forward deceleration conditions, reverse acceleration conditions, reverse deceleration conditions, and zero-crossing switching conditions.

[0088] The gradient query and correction module selects the corresponding basic adjustment gradient table based on the identified working conditions, and obtains the basic adjustment gradient Gbase by querying the actual speed and speed deviation as indexes. At the same time, it obtains the first correction coefficient K1 by looking up the table with the throttle opening and the actual speed, and obtains the second correction coefficient K2(λ) by looking up the table with the load torque ratio λ. Then, it multiplies the three to obtain the speed filtering gradient Gzc.

[0089] The incremental filter calculation module first calculates the speed deviation Δn=ntarget -n actual Then, the speed deviation is multiplied by the filtering gradient to obtain the speed increment. Under non-zero-crossing conditions, the actual speed is added to the speed increment to obtain the filtered target speed. If the current condition is zero-crossing switching, the smoothing factor is obtained by querying the smoothing factor table based on the actual speed and speed deviation. The speed increment is multiplied by the smoothing factor and then added to the actual speed to obtain the target speed after zero-crossing smoothing.

[0090] The safety monitoring and limiting module first determines whether the target speed exceeds the maximum or minimum speed range allowed by the motor. If it does, it clamps the speed to the extreme value. Then, based on the preset range of the load torque ratio λ (such as λ<0.8, 0.8≤λ<1.0, 1.0≤λ<1.1, λ≥1.1), it determines the corresponding overload compression ratio (e.g., 1, 0.6, 0.3, 0.15), compresses the adjustment amount that exceeds the actual speed, and finally outputs the safe target speed.

[0091] The propulsion inverter is electrically connected to both the propulsion motor and the propulsion engine. It receives the target safe speed output and generates a PWM drive signal using vector control or direct torque control algorithms, which is then output to the propulsion motor. Under the influence of the PWM drive signal, the propulsion motor operates smoothly according to the command, while simultaneously feeding back its actual speed, actual torque, and maximum allowable torque, among other operating parameters, to the propulsion inverter in real time. This feedback is then transmitted back to the inverter, forming a complete closed-loop control chain. Through the coordinated operation of these functional units, the system can sense the load status in real time, adaptively adjust the filter gradient, cover all navigation conditions, and implement graded overload protection, thereby effectively suppressing sudden speed changes and overcurrent faults, improving the safety of ship navigation and extending equipment lifespan.

[0092] The workflow of this system is as follows: First, the driver sends operation signals such as requesting to straighten the vehicle, requesting to reverse, requesting to accelerate, requesting to decelerate, requesting to change direction, and requesting throttle opening by operating the push handle; The propulsion control unit (PCS) collects these signals in real time and obtains operating parameters such as the actual speed, actual torque, maximum allowable torque, maximum speed and minimum speed of the propulsion motor through the propulsion frequency converter.

[0093] After the propulsion remote control module inside the propulsion remote control unit analyzes the input signal, the torque ratio calculation module calculates the load torque ratio λ=Tq. actual / Tq maxThis is used to quantify the current load rate. The operating condition identification module accurately determines the current navigation operating condition of the ship based on preset rules (such as throttle opening threshold, speed threshold, comparison between target speed and actual speed, and direction switching request), including six operating conditions: starting, forward acceleration, forward deceleration, reverse acceleration, reverse deceleration, and zero-crossing switching. The gradient query and correction module selects the corresponding basic adjustment gradient table based on the identified operating condition, using the actual speed and speed deviation Δn=n. target -n actual To index the base gradient Gbase, the first correction coefficient K1 is retrieved using throttle opening and actual speed as indexes, and the second correction coefficient K2(λ) is retrieved using the load torque ratio λ as an index. These three are then multiplied to obtain the speed filtering gradient Gzc. The incremental filtering calculation module first multiplies the speed deviation Δn by the filtering gradient Gzc to obtain the speed increment. Under non-zero-crossing switching conditions, the actual speed is directly added to this increment to obtain the filtered target speed. If the current condition is a zero-crossing switching condition, the smoothing factor (smooth) is obtained by querying the smoothing factor table based on the actual speed and speed deviation. factor The speed increment is multiplied by a smoothing factor and then added to the actual speed to obtain the target speed after zero-point smoothing. The safety monitoring and limiting module first determines whether the target speed exceeds the maximum or minimum allowable speed range of the motor. If it does, it clamps to the extreme value. Then, based on the preset range of the load torque ratio λ (such as λ<0.8, 0.8≤λ<1.0, 1.0≤λ<1.1, λ≥1.1), it determines the corresponding overload compression ratio (e.g., 1, 0.6, 0.3, 0.15), compresses the adjustment amount exceeding the actual speed, and finally outputs the safe target speed to the drive inverter.

[0094] After receiving the target speed, the propulsion inverter generates a PWM drive signal using vector control or direct torque control algorithms, driving the propulsion motor to operate smoothly at the target speed. Simultaneously, the propulsion motor feeds back operating parameters such as actual speed, actual torque, and maximum allowable torque to the propulsion inverter in real time, which then transmits these parameters back to the propulsion remote control unit, forming a complete closed-loop control system.

[0095] Throughout the process, the remote control unit continuously monitors torque ratio fluctuations and speed tracking errors, optimizes gradient lookup table parameters online, and implements fault diagnosis and graded overload early warning protection, thereby achieving adaptive, smooth, and safe control of the target speed of the propulsion motor.

[0096] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for adaptive control of the target speed of a propulsion motor in an electric propulsion ship, characterized in that, include: Collect driver operation signals and propulsion motor operating parameters; Calculate the load torque ratio based on the propulsion motor operating parameters; Based on the driver's operation signals and propulsion motor operating parameters, the current navigation condition is identified through preset rules. The navigation conditions include starting condition, forward acceleration condition, forward deceleration condition, reverse acceleration condition, reverse deceleration condition, and zero-crossing switching condition. Based on the propulsion motor operating parameters, load torque ratio and current navigation conditions, the gradient table is queried and corrected to determine the speed filtering gradient. The target rotational speed is calculated using an incremental filtering algorithm based on the aforementioned rotational speed filtering gradient. When the zero-crossing switching condition is underway, a smoothing factor is introduced to correct the target speed; A safe target speed is obtained by applying a safety limit to the target speed based on the maximum speed and minimum speed of the propulsion motor and the load torque ratio. The propulsion motor is controlled based on the target speed for safety.

2. The adaptive control method for the target speed of the propulsion motor of an electric propulsion ship according to claim 1, characterized in that, The driver operation signals include: The initial target speed of the propulsion motor, forward driving request, reverse driving request, acceleration request, deceleration request, forward / reverse direction switching request, and throttle opening; The operating parameters of the propulsion motor include: the actual speed, actual torque, maximum allowable torque, maximum speed, and minimum speed of the propulsion motor.

3. The adaptive control method for the target speed of the propulsion motor of an electric propulsion ship according to claim 2, characterized in that, The formula for calculating the load torque ratio is: λ=Tq actual / Tq max Among them, Tq actual To increase the actual torque of the motor, Tq max To drive the maximum allowable torque of the motor.

4. The adaptive control method for the target speed of the propulsion motor of an electric propulsion ship according to claim 2, characterized in that, The preset rules include: When the driver operation signal is a request to move forward or reverse, the throttle opening is greater than a preset throttle opening threshold, the initial target speed is greater than the actual speed, and the absolute value of the actual speed is less than a preset speed threshold, it is identified as the starting condition. When the driver operation signal is a forward acceleration request, the throttle opening is greater than a preset throttle opening threshold, the actual speed is greater than zero, the initial target speed is greater than the actual speed, and the absolute value of the actual speed is greater than or equal to a preset speed threshold, it is identified as the positive acceleration condition. When the driver's operation signal is a reversing request, the throttle opening is greater than the preset throttle opening threshold, the actual speed is less than zero, and the absolute value of the initial target speed is greater than the absolute value of the actual speed, it is identified as the reverse acceleration condition. When the driver's operation signal is a request to move forward, the actual speed is greater than zero, and the initial target speed is less than the actual speed, it is identified as the positive deceleration condition. When the driver's operation signal is a reversing request, the actual speed is less than zero, and the absolute value of the initial target speed is less than the absolute value of the actual speed, it is identified as the reverse deceleration condition. When the driver's operation signal is a request to switch between forward and reverse directions, and the actual speed is lower than the zero-crossing speed threshold, it is identified as the zero-crossing switching condition.

5. The adaptive control method for the target speed of the propulsion motor of an electric propulsion ship according to claim 2, characterized in that, The step of determining the speed filtering gradient by querying and correcting the gradient table based on the propulsion motor operating parameters, load torque ratio, and current navigation conditions specifically includes: Calculate the speed deviation based on the initial target speed and the actual speed; Determine the corresponding basic adjustment gradient table based on the current navigation conditions; Using the actual speed and speed deviation as indexes, the basic adjustment gradient corresponding to the current navigation condition is obtained by querying the basic adjustment gradient table; Using the throttle opening and actual speed as indexes, the first correction coefficient is obtained by looking up a table; Using the load torque ratio as an index, the second correction coefficient is obtained by looking up a table; The speed filtering gradient is obtained by multiplying the basic adjustment gradient, the first correction coefficient, and the second correction coefficient.

6. The adaptive control method for the target speed of the propulsion motor of an electric propulsion ship according to claim 5, characterized in that, The target rotational speed is calculated using an incremental filtering algorithm based on the rotational speed filtering gradient. When in a zero-crossing switching condition, a smoothing factor is introduced to correct the target speed, specifically including: Multiply the speed deviation by the speed filtering gradient to obtain the speed increment; The actual rotational speed is added to the rotational speed increment to obtain the target rotational speed under non-zero-crossing switching conditions; When the zero-crossing switching condition is in effect, the smoothing factor is obtained by looking up a table based on the actual speed and speed deviation. Multiply the speed increment by the smoothing factor to obtain the corrected speed increment; The target speed under the zero-crossing switching condition is obtained by adding the actual speed to the corrected speed increment.

7. The adaptive control method for the target speed of the propulsion motor of an electric propulsion ship according to claim 1, characterized in that, The method of applying a safety limit to the target speed based on the maximum speed, minimum speed, and the load torque ratio to obtain a safe target speed specifically includes: Determine whether the target rotational speed exceeds the extreme range of the maximum or minimum rotational speed; if so, clamp the target rotational speed to the corresponding extreme value. Based on the preset range in which the load torque ratio falls, determine the corresponding overload compression ratio; The adjustment amount exceeding the actual speed is compressed using the overload compression ratio to obtain the safe target speed after graded overload limitation.

8. The adaptive control method for the target speed of the propulsion motor of an electric propulsion ship according to claim 7, characterized in that, The step of determining the corresponding overload compression ratio based on the preset range in which the load torque ratio falls specifically includes: When the load torque ratio is less than the first threshold, the overload compression ratio is 1; When the load torque ratio is greater than or equal to the first threshold and less than the second threshold, the overload compression ratio is the first compression value; When the load torque ratio is greater than or equal to the second threshold and less than the third threshold, the overload compression ratio is the second compression value; When the load torque ratio is greater than or equal to the third threshold, the overload compression ratio is the third compression value; The third compression value is less than the second compression value, which is less than the first compression value.

9. The adaptive control method for the target speed of the propulsion motor of an electric propulsion ship according to claim 8, characterized in that, The first threshold is 0.8, the second threshold is 1.0, and the third threshold is 1.1; the first compression value is 0.6, the second compression value is 0.3, and the third compression value is 0.

15.

10. An adaptive control system for the target speed of a propulsion motor in an electric propulsion ship, characterized in that, include: Propulsion handle, propulsion remote control unit, propulsion inverter, and propulsion motor; The push handle is used to send driver operation signals; The propulsion remote control unit is electrically connected to both the propulsion handle and the propulsion frequency converter, and is configured as follows: Receives driver operation signals from the propulsion handle and propulsion motor operating parameters fed back by the propulsion frequency converter; Calculate the load torque ratio based on the propulsion motor operating parameters; Based on the driver's operation signals and propulsion motor operating parameters, the current navigation condition is identified through preset rules. The navigation conditions include starting condition, forward acceleration condition, forward deceleration condition, reverse acceleration condition, reverse deceleration condition, and zero-crossing switching condition. Based on the propulsion motor operating parameters, load torque ratio and current navigation conditions, the gradient table is queried and corrected to determine the speed filtering gradient. The target rotational speed is calculated using an incremental filtering algorithm based on the aforementioned rotational speed filtering gradient. When the zero-crossing switching condition is underway, a smoothing factor is introduced to correct the target speed; A safe target speed is obtained by applying a safety limit to the target speed based on the maximum speed and minimum speed of the propulsion motor and the load torque ratio. The propulsion inverter is electrically connected to the propulsion remote control unit and the propulsion motor respectively, and is configured to: receive the safe target speed, generate a PWM drive signal and output it to the propulsion motor; The propulsion motor is electrically connected to the propulsion frequency converter and is configured to operate under the control of the PWM drive signal, and to feed back the current propulsion motor operating parameters to the propulsion frequency converter, and then transmit them back to the propulsion remote control unit to form a closed-loop control.

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