Operation control and simulation research of the variable-speed constant-frequency system of the ship shaft generator

This paper introduces the operational principle of the variable-speed constant-frequency (VSCF) control system of the ship shaft generator and analyzes the control task and working characteristic of system before and after grid-connection. On the basis of mathematical model of the doubly-fed induction generator (DFIG), it gives the mathematical model of the vector control technique oriented by the stator flux of the generator. And it researches the no-load grid-connection control and the power decoupling control strategy based on stator flux oriented vector control technology. A simulation model is built in Matlab/Simulink circumstance. Specifically, in order to research generator no-load operation, grid-connection, independent active/reactive power adjustment and so on, the time-sharing modeling idea is adopted for the no-load grid-connection model and the grid-connected power generation model to simulate the whole processes of the system from grid-connection to power generation in a time-sharing manner. The results demonstrate that the shaft DFIG system has good performance on tracking the reference voltage and stabilizing the given frequency, and it has satisfactory dynamic and steady-state characteristics when generator speed or load is changed. The complete simulation research verifies the modeling & control correctness and effectiveness of the variable-speed constant-frequency control system of the ship shaft generator.