The Optimization Research Of Ship Electric Propulsion And Control Strategy Based On PMSM

With the rapid development of high-tech technologies, such as power electronic technology, AC frequency conversion technology, modern control technology, as well as new energy and new materials, the ship electric propulsion system has a breakthrough in energy efficiency, mechanical reliability and propulsion performance, which makes the application field of ship electric propulsion technology continue to expand, and determines the development direction of future ship.Undoubtedly, PMSM is the best selection for electric machine on ship electric propulsion system. Its advantages in low speed, high torque and high efficiency could guarantee that the system has good performance under complicated working condition. However, because of the poor working condition that ship works, such as vibration, nonlinearity, tight coupling and large inertia lag, as well as suffering from external interference of wind, wave and current, how to improve the electric propulsion efficiency has become an important subject to research. Therefore, the optimization study of control strategy for electric propulsion system electric propulsion system based on PMSM was carried out in this paper. In view of the dynamic characteristics, static characteristics and load characteristics of ship electric propulsion system, the control strategy and algorithm optimization of the vector control of PMSM was mainly researched so that the system’s propulsive performance and safety performance could be improved. The main tasks and responsibilities are followed:1. The research results of ship electric propulsion system at home and abroad was collected to analysis the structural characteristics of ship electric propulsion system, including PMSM, vector control technology, as well as propeller load characteristic. Based on studying the mathematical model of each module, the simulation models of PMSM and ship paddle were set up in Matlab/Simulink, and the correctness of ship electric propulsion system model could be verified via simulation.2. By analyzing the double closed-loop vector control system of PMSM, a torque loop control was added on the basis of the original to overcome the disadvantages of steady state performance. The control strategy optimization, which made the rotating torque output regulate directly, could reduce the torque ripple effectively and realize the effect of vibration damping.3. For the disadvantages that propulsion system with PI control has poor robustness and no online self-tuning function, an embedded fuzzy controller in the category of variable domain was designed. It made the fuzzy output have the function of online self-tuning for scaling factor, achieved the optimization of control algorithm, and also improved the system dynamic characteristics and disturbance resistance properties. At the same time, the introduction of integral action could effectively restrain the system static error.4. Combined with the above optimization results, a complete hull-motor-propeller simulation model was built in Matlab to research the propulsion performance that ship electric propulsion and control system was from starting to steady under variable load. Finally, according to the output waveform of each parameter to analysis and summary the result.