Simulation Research On Small Marine Electric Propulsion System

Since the 80 s of last century,the progress of power electronics has promoted the frequency conversion speed regulation technology to mature.Its performance is comparable to that of DC speed regulation system,making the electric propulsion system of the ship have been improved by leaps and bounds.At present the research of the ship electric propulsion is still in the initial state,applied to the real environment when there are still some problems,so it is necessary to explore the ship electric propulsion system is of far-reaching significance,to a great extent,can promote the development of marine electric propulsion technology.In this paper,three phase asynchronous motor is used as the main research object of the ship electric propulsion system.First,the mathematical model of the three-phase asynchronous motor is set up,and the basic principle of the three-phase asynchronous motor vector control is analyzed.Then,the principle and implementation algorithm of voltage space vector control are deeply studied,and the simulation model of voltage space vector control system is built,and the stator current,torque and speed of the motor are analyzed.The results show that the operating state of the voltage space vector control system is good and the torque ripple of the motor is small.Secondly,the speed signal collector is estimated using the method of speed identification based on MRAS to the motor speed to replace the traditional MRAS,established on the basis of the speed sensor-less vector control system based on the established simulation model,simulation of the model results can be seen,the motor speed is calculated based on MRAS method has significant the effect in the actual speed of tracking motor,calculated by this method can speed the actual motor speed tracking well.Finally,according to the detailed performance of propeller load,and analyzed the characteristics of bounded form the four quadrant propeller,by using the Chebyshevd polynomial to fit the characteristics of the map,simulation model of ship propeller is established,combined with the oar model and MRAS speed control system based on vector sensor model.To build a complete electric propulsion system model,the simulation results of the model analysis,the ship electric propulsion system with steady performance without the speed sensor-less vector control method can not only obtain better but also has a good dynamic performance.