Design Of Digital Control System For Marine Permanent Magnet Synchronous Motor

Marine electric propulsion technology has the advantages of wide range of speed regulation,easy installation,flexible operation and so on,which has been widely used in the world shipbuilding powerful countries.Permanent magnet synchronous motor has many advantages,such as high power density,high efficiency and good control performance,which is very suitable to be used as propulsion motor of electric propulsion ship.Therefore,the research on the control system has important theoretical significance and practical value.This paper takes the permanent magnet synchronous motor as the control object,and mainly analyses the theory of direct torque control thoroughly.On this basis,the control system of permanent magnet synchronous motor is designed.Firstly,the paper summarizes the research status of marine electric propulsion technology and permanent magnet synchronous motor.According to the mathematical model of permanent magnet synchronous motor,the direct torque control method is introduced.The method of direct torque control based on space vector pulse width modulation is analyzed.Secondly,analyze the relationship between the power factor angle and the stator flux based on improving the power factor and the operating efficiency of permanent magnet synchronous motor.Combined with space vector pulse width modulation technique,a method of direct torque control based on flux adaptive unit power factor is studied.The implementation process,especially the calculation method of given stator flux amplitude is deduced in detail.And the simulation model of flux adaptive control is established on the Matlab/Simulink platform,and simulation results are analyzed.The results show that the control method can make the motor work under the condition of unity power factor.Then in order to solve permanent magnet synchronous motor direct torque control torque ripple problem,research on feedback linearization algorithm and determine the exact linearization condition,and design a feedback linearization controller,based on space vector pulse width modulation technology,and realize feedback linearization direct torque control method.and establish the simulation model for the simulation analysis.The simulation results show that the introduction of feedback linearization can effectively reduce the ripple of the control system.Then combine with the flux adaptive direct torque control method and feedback linearization direct torque control method.The feedback linearization direct torque control strategy for permanent magnet synchronous motor based on flux adaptive is studied to improve power factor and effectively reduce the torque ripple.The simulation model is established and the simulation results show that the control method can make the motor work in the unit power factor and reduce the torque ripple.Finally,the hardware and software of permanent magnet synchronous motor control system is designed.The main circuit of the system is built,and the DSP chip TMS320F2812 is used as the control core,and the drive and isolation circuit,signal detection circuit and protection circuit are designed.In the CCS3.3 development environment,complete the software system programming,including the control system main program,interrupt subroutine and fault protection programs,etc..Through the construction of the experimental platform,the control system of this paper is tested,and some experimental waveforms are obtained.Analyze the experiment results and verify the effectiveness of the direct torque control strategy.