Research On Simulation Of Ship Electric Propulsion System

Electric propulsion system is economical and efficient,also can save energy.It is a popular research in domestic and foreign shipping industry,and has been widely used in ships.Based on the ship electric propulsion system,the simulation model of electric propulsion system with inverter,motor and propeller is built.The fault model is established on the basis of normal model and the ship is maintained in time to ensure the safe and stable operation of the ship.Firstly,the topological structure of the diode intermediate point clamp H bridge converter is proposed.The SVPWM control strategy and SPWM control strategy of carrier cascade and carrier phase shift are respectively used for theoretical analysis and simulation.Secondly,the mathematical model of the five-phase induction motor in the vector space is established according to the rotor flux orientation.The controller is designed in detail and the predictive control model is also analyzed.Based on the mathematical model and structure of the motor,the control strategy of PI control and the combination of predictive control and PI are analyzed.The two control methods are simulated respectively.Thirdly,the working characteristics of propeller are analyzed and studied.The main parameters such as the thrust coefficient and the drag coefficient are corrected.The corrected curves are fit by using Chebyshev polynomials.The mathematical model of motor and propeller are established.The ship of positive and backward navigation working condition are simulated.Finally,the failure simulation model is rebuilt on the basis of the normal model of electric propulsion system.An IGBT open circuit fault simulation model for inverter is established.The simulation model of the lack of phase fault is established for the motor.According to the fault characteristic curve of various faults,the fault can be found in time,the electric propulsion system is maintained,and the safe and stable operation of the ship can be ensured.