Robust sensorless control of BLDC Motor using second derivative function of the sum of terminal voltages

This paper proposes a new sensorless control method for the speed and position control of a BLDC Motor. This sensorless drive technique calculates the commutations instants (duration of commutation) by deriving the sum of the terminal voltages of the motor (SigVi). Thus, it is possible to estimate the rotor position (and back EMF of the motor) by only using measurements of the stator line currents and voltages. The implantation of these detectors is easy and cheap. This method is quite robust across variations in stator resistance due to changes in temperature or frequency. With this method the motor can be started without needing the initial position of the rotor. This proposed method is validated through extensive simulations at different speeds, and a very satisfactory performance has been achieved

Comparative Study between Sliding Mode Control and the Vectorial Control of a Brushless doubly fed induction generator

Brushless doubly fed induction generators (BDFIG) show commercial promise forwind-power generation due to their lower capital and operational costs and higher reliability ascompared with doubly fed induction generators. This paper proposes a robust sliding mode control of grid-connected brushless doubly fed induction generator (BDFIG). The developed algorithm is based on the decoupling control by using oriented grid flux vector control strategy. The decoupling of the active and the reactive stator powers insures an optimal performance of the BDFIG at the sub-synchronous region. The stator of this machine incorporates two sets of three phase windings with different number of poles, power winding (PW) and control winding (CW). The proposed method is tested with the Matlab/Simulink software. Simulation results illustrate the performances and the feasibility of the designed control