The Research Of Marine Shaft Brushless Doubly-Fed Machine's Control Algorithms

The shipboard electric power system has been dependent on diesel generator set, which making operating costs stay high, causing environmental pollution at the same time. Brushless Doubly-Fed Machine(BDFM) have wide application in the control-frequency saving-energy adjustable speed drive(ASD) systems and the constant-voltage constant-frequency(CVCF) variable speed generation(VSG) systems. After a long development, BDFM gradually reached the practical stage. Therefore, using ship main engine to drive BDFM to generate had caused widespread concern.Firstly, the working principle of BDFM has been analyzed. And a math-model of BDFM under the static abc coordinate system has been set up based on the motor theory. The model has been further simplified and the two-phase dq model in rotor-speed rotation coordinate system has been derived by using the coordinate transformation, which lays the basis for the subsequent simulation work. In order to facilitate the steady-state analysis, further deduced steady equivalent circuit of BDFM.Secondly, the scalar control strategy for BDFM Ship Shaft independent power system has been presented. And put forward an improved scalar control to strengthen the resistivity against load disturbances—current feedforword control. This paper also proposed no speed sensor algorithm. When the speed sensor damaged, the system can automatically identify and switch to no sensor mode. The simulation model of the control system has been built up by using the MATLAB/Simulink toolbox.Finally, set up the experimental platform of BDFM Ship Shaft independent power system. A variety of operating conditions were simulated, such as electricity load changes, and Windlass start, to analysis the experiment voltage. And the current feedforward compensation algorithm and sensorless algorithms through the experimental analysis. Many tests show the correctness of the theory.