Research On Ship Electric Propulsion System Based On Speed Sensorless

This paper mainly studies the ship electric propulsion system based on speed sensor.Compared with the traditional three-phase asynchronous propulsion motor,the five-phase propulsion motor used in this paper has the advantages of large output torque and strong fault tolerance.It uses five-phase LC filter.The frequency converter is used as the power supply device of the propulsion motor.The motor control system adopts vector control and the propeller twin propeller model is established.Finally,the estimation of the motor speed of the ship’s electric propulsion system is completed.The mathematical model of the five-phase propulsion motor and the five-phase inverter model are established.In order to facilitate the design of the five-phase asynchronous motor vector control system,the five-phase inverter model is simplified and designed as a first-order inertia link,and then the vector control is designed The regulators of the inner ring and outer ring of the system,and the amplitude-phase characteristic curve of the d-axis and q-axis open-loop transfer function prove the stability of the design of the vector control system of the propulsion motor.Analyzed the open water characteristics of the single propeller model of the propeller,established a five-phase asynchronous motor single propeller model propulsion system and simulated analysis of common operating conditions.Based on the single propeller model,the double propeller model was established considering the axial mixing flow of the propeller.The common operating conditions of the twin-propeller propulsion system are simulated and analyzed.To observe the rotor flux of the propulsion motor of the ship’s electric propulsion system,the extended state observer(ESO)scheme is used,and compared with the current model rotor flux observation method,it shows that the ESO model is robust to the motor rotor resistance.Based on the flux observation model,a closed-loop extended state observer for rotor flux(CESO)is established,which improves the dynamic performance of the rotor flux observation model and reduces the influence of rotor resistance on the accuracy of flux observation.Based on the ESO rotor flux observation model,an interactive speed estimation method is proposed,that is,the two parameters of the speed and the rotor time constant are estimated at the same time,and the simulation model is established by simulink.However,this method is robust to the stator resistance.In order to improve the accuracy of speed estimation,an interactive MRAS induction motor speed estimation method based on joint identification of speed and stator resistance is further proposed.Simulations have proved that this method has higher accuracy in speed estimation and system dynamics.The performance is better;finally,the model of the ship’s electric propulsion system based on the sensorless speed is established and simulated by the interactive MRAS rotation speed observation method,which verifies the accuracy of the twin propeller model,the flux linkage observation and the rotation speed observation.