Research On Sensorless Control Of Permanent Magnet Synchronous Motor In Full Speed Range Based On Propeller Load

With the progress of high-power AC speed regulation system and the development of power electronics technology,as well as the launch of energy-saving and consumption-reducing strategy in the 11 th Five-Year Plan of China,electric propulsion has become the development trend of international ship propulsion mode after entering the 21 st century.However,the practical application of this technology is still limited in China,and it is of great significance to explore the ship electric propulsion.In this paper,the sensorless control of permanent magnet synchronous motor(PMSM)based on propeller load is studied,and the full speed range sensorless control technology is studied.Firstly,the mathematical models of the built-in permanent magnet synchronous motor in different coordinate systems are analyzed and deduced,and the common control strategies and salient pole characteristics of the built-in permanent magnet synchronous motor are studied,and the corresponding vector control simulation model is established and analyzed.Secondly,the basic principle of sliding mode observer used in medium and high speed section is introduced.In the design of observer,improvement measures are adopted for chattering problem,mainly from three aspects: switching function,back EMF value and cut-off frequency of low-pass filter.Secondly,the basic principle of the pulse high frequency injection method used in the low speed section is introduced,and the mathematical model of the built-in permanent magnet synchronous motor under high frequency excitation is reconstructed.The processing process of the high frequency response current and the rotor position estimation method are analyzed in detail.Then,the characteristic parameters of the propeller load and their interconnection are studied one by one,and the working mechanism of the propeller in the actual fluid environment is studied.Then the ship propeller simulation model is built to verify that its output characteristics basically conform to the changing law of the actual system.Based on the fact that a single sensorless algorithm can't realize the full speed control of marine motor,this paper combines the sliding mode observer with the pulse high frequency injection method by weighting function,and builds a full speed sensorless control system based on the propeller load with the help of MATLAB/Simulink.The simulation results show that there is no obvious fluctuation of the speed and position in the transition zone,and the switching of the composite control has passed.With smooth range and steady speed increase,sensorless control of PMSM in full speed range is realized.