Research On Digital Control Of Marine Hybrid Shaft Permanent Magnet Synchronous Motor

Fossil fuel is the main power energy in modern marine, but the transformation efficiency is unsatisfactory. So hybrid shaft generator system is focused by more and more people, for it can not only drive the propeller separately or together with the main engine, but also supply power to the load with the diesel generator. Based on the operation mode of hybrid shaft generator system, the thesis mainly studies the motor Vector Control (VC), Pulse Width Modulation (PWM) rectifier control and verified by MATLAB_SIMULINK platform, then analyzes the tuning of rotor field initial position and modulation relationship between SPWM and SVPWM. This essay consists of the following three parts.Firstly, mathematical model of shaft permanent magnet motor and theory of Vector Control are presented. So torque control can be simplified to the control of quadrant current linearly based on the VC with id=0;for the convenience of debugging, speed control system is designed and makes a comparison between1-DOF PI controller and2-DOF PI controller.Secondly, PWM rectifier model is analyzed in detail, and designs the cascaded controller on the basis of VOC. Based on traditional voltage and current dual-loop control, a novel control strategy using square of voltage and current as feedback is presented in this paper to improve system performance, such as dynamic responding time of DC voltages and AC currents, and immune to load variation.Thirdly, a research on the measurement of speed and initial position tuning are made. Three key methods are presented:T method, M method and M/T method, then illustrates the digital realization of M/T method. For the balanced three-phase DC synthesize constant field, so initial position can be learned by this way. In addition, it is obtained that SVPWM wave can be derived from SPWM.Finally, a50kVA variable-speed-constant-frequency prototype is designed to verify the validity of above.