Design Of Variable Frequency Control Speed System Trial In Electric Twin-pod Propulsion

Podded propulsion is a new focus in development of ship propulsion system. The debut of it accelerated the development of electric propulsion. But the study of podded propulsion is just studied interiorly, so doing the research of the podded propulsion is necessary. The thesis mainly introduces the design and debugging of the trial of speed adjustment system in the electric twin-pod propulsion.The thesis consists of 7 chapters. In the beginning, it introduces the development of the electric propulsion ship, then introduces the structure and composing of the podded propulsors in detail;and it presents theories, instruments and means of the trial also. It explains the principle both of the inverter and PLC, and introduces the control-mode and the choice type of them detailedly. Because the trial of variable frequency control system adopts the mean of digital PID control, the controlment and digital PID control are implemented by PLC, so the thesis elaborates the principle of PID and analyses parameters' physical meaning, then designs the implementation of digital PID. The thesis gives the system structure picture, system composing picture and the flow chart of the program. For the network, the paper introduces the communication between computer and the PLC based on PROFIBUS-DP. Based on the above study, the author of this paper designed variable frequency control speed system in electric twin-pod propulsion. This system has the excellent performance of the speed control through the repetitious trial. The system can implement two motors starting work at same time and not, and motors can be controlled by discretional given input signal. In order to find the appropriate parameters, debugging to the system is necessary. The paper introduces the process of debugging and presents results of the whole trial. After analyzing the results of the trial, it proves this trial design achieved the anticipate requests.Key conclusions are given at the end of the thesis. Problems and drawbacks of the researching process are discussed, according to which some suggestions are given for further research.