LQR control for superconducting magnetic energy storage on distribution networks using feedback linearization

This paper presents a control scheme applied to superconducting magnetic energy storage systems (SMES). The SMES is integrated to the grid using a pulse-width-modulated current source converter (PWM-CSC) which is an straightforward alternative to conventional topologies due to its intrinsic current characteristic. A novel representation of the system is obtained using feedback linearization. An average representation of the converter is considered with the modulation indices as control inputs. The dynamical system is transformed form no-autonomous into an autonomous system by application the power invariant Park's transformation from the abc reference frame into a dq reference frame. Results demonstrate the efficiency of the proposed control to modify the total energy stored in the superconducting coil by modification of its dc current guaranteeing stability in closed-loop.