A Novel DTC-based Control Method of Flywheel System to Improve Fault-Ride Through Capability of the Microgrids

Other conference contribution, 2019

This paper proposes a new control method for Flywheel Energy Storage System (FESS) to guarantee a Fault-Ride
Through (FRT) capability of the sensitive microgrids like big data centers. The proposed method has been developed
towards a twofold aim: regulating constant common DC-bus voltage, during serious voltage dips caused by the grid side
electrical faults and also keeping a constant charge current during normal operation of the grid. The proposed FESS
is coupled with Permanent Magnet Synchronous Machine (PMSM). The speed sensorless Direct Torque Control (DTC)
the technique has been developed for PMSM control and the Extended Kalman Filter (EKF) is used to estimate the rotor
position and consequently the rotor speed. The main contributions of the overall control method are: (i) the decoupled
disturbance control at discharge mode copes with sudden load change disturbances; (ii) the DTC provides fast and
precise torque response; (iii) the real-time speed estimation by the EKF increases the speed and the accuracy of the
overall control system; (iv) the proposed FESS can be easily replaced by the Battery Energy Storage System (BESS).
The proposed system and the corresponding control method are verified in the MATLAB/Simulink environment. The
simulation results confirm the effectiveness of the proposed control method.