Sharif Digital Repository

The paper presents the vector model of the Brushless Doubly-Fed Machine (BDFM) in the rotor flux oriented reference frame. The rotor flux oriented reference frame is well known in the standard AC machines analysis and control. Similar benefits can be sought by employing this method for the BDFM The vector model is implemented in MATLAB/SIVIULINK to simulate the BDFM dynamic performance under different operating conditions. The predictions from the vector model are compared to those from the coupled circuit model in simulation. The results are shown for the cascade mode of operation. © 2008 IEEE  

Brushless doubly fed machine (BDFM) shows promising results for wind power and adjustable-speed drive applications. Due to poor rotor magnetic coupling and relatively high value of slip, core loss is more emphasized in this machine than the conventional machines. By now, there are few comprehensive researches on core loss effect on performance characteristics of BDFM in the literature. In this paper, based on the derived relations and by applying suitable rules for transformation of parameters from one winding to another one, the steady state equivalent circuit model of BDFM referred to power winding stator side is obtained. Comparison between simulation and experimental results verifies the... 

Position sensorless control of ac machines at zero and low speed is possible using high-frequency carrier injection methods. These methods utilize anisotropic properties of rotor. Therefore, they may lose their efficiency for nonsalient machines or machines with small rotor saliency. In these machines, measurement noise and offset, existing delays, as well as model uncertainties may lead to inaccurate estimation of rotor position. Stator resistance which is usually neglected in these methods may also lead to a considerable error especially in machines with small rotor saliency. In this paper, a new position estimation method is presented, and it is shown that in comparison to conventional... 

This paper presents a dynamic model for brushless doubly fed machine including core loss. Using the space vector notation, the conventional equivalent circuit model of the machine is modified to take the core loss effect into account. The proposed method introduces resistances corresponding to stator/rotor core loss components designated to the power/control windings. This model can be used for enhanced time-domain simulations, design of high performance control strategies with core loss detuning effect compensation and also as a tool for stability analysis of the machine drive under different control methods. The dynamic model of a prototype machine is simulated with and without... 

Sensorless control of permanent magnet synchronous motors allows reducing cost and complexity, and increasing mechanical robustness and noise immunity. Sensorless methods based on high frequency carrier injection have attracted considerable attention in recent years as they can estimate rotor position in a wide speed range. These methods employ anisotropic properties of rotor to estimate rotor position in ac machines. With internal permanent magnet motors, the high frequency signal injection method can deliver precise sensorless control, however in surface-mounted permanent magnet machines, where a small saliency arises from main flux saturation, the estimation of rotor magnet position is...