The Research On Control Of The Marine Brushless Doubly Fed Shaft Generator System

Nowadays with the increasing scarcity of fossil energy and more and more serious on environmental protection, energy saving and emission reduction is represent the general trend. Using the shaft generator system at ship can reduce diesel oil consumption and the pollution of the environment.It is one of the important technology of ship energy saving and emission reduction.The brushless doubly fed machine is a shaft generator which is applicable to fixed pitch propeller ship. It needs a little improvement based on the ordinary induction motor, which is using special rotor structure,increasing the frequency converter of a small capacity to realize constant frequency constant pressure power generation in a wide speed range, and cancelling the brush slip ring device. The brushless doubly fed machine has the advantages of simple structure, safe and reliable operation, easy maintenance and low cost. Marine brushless doubly fed shaft generator system is the application of brushless doubly fed machine to the ship shaft generator field, has a strong practicality and popularization and application value.This paper takes marine brushless doubly fed shaft generator control system as the research object, and studies the operation rules and control methods of the system in the independent generation state. It emphatically analysis the brushless doubly fed machine of stator and rotor structure, the basic electromagnetic relation, synchronous and asynchronous operation principle and the principle of variable speed constant frequency generation. It explores the energy transfer relationship of the brushless doubly fed machine in the independent generation state. It establishes multi loop model, rotor speed d-q model and double synchronous speed model which are several kinds of main mathematical model of the brushless doubly fed machine.This paper analyzes the composition and the features of the marine brushless doubly fed shaft generator control system. By using the scalar and vector control strategy, it study and simulate the regulating frequency and voltage problem in the condition of the independent generation. The voltage and current double closed-loop control are used for scalar control. The two models of voltage source converter and current source inverter are studied respectively. Vector control is stator field oriented vector decoupling control strategy based on dual synchronous coordinate model, and it realize the complete decoupling of two stator windings of the brushless doubly fed machine. According to the mathematical model of the Matlab/simulink software, two control strategies are modeled and simulated. Simulation results show that the two kinds of control strategy can satisfy requirement of the ship’s power supply standards, realize variable speed constant frequency and constant voltage power generation. The dynamic performance of vector control is more superior. Finally, taking DSP TMS320F28335 as the control core, the hardware design of the marine brushless doubly fed shaft generator system experimental platform has been initially completed.