Modeling and control of a STATCOM-supercapacitors energy storage system associated with a wind generator

The influence of constant speed wind turbine in an electrical network during torque impact can lead various problems. The disturbances affect active power quality, reactive power and r.m.s. phase to phase voltage. In this paper, we propose an original system and control to solve firstly, the problems due to the brutal impact of active power and secondly the control of reactive power. The principle of the proposed wind energy system with STATCOM-supercapacitors energy storage is to limit the rapid variation of active power and give the required reactive power compensation to the induction machine during the torque change. The supercapacitor is directly coupled to the common dc-link of the whole bidirectional DC-AC converter. The control strategy of the STATCOM use a Linear Matrix Inequalities (LMIs) technic to regulate the currents injected or absorbed by the inverter. The same strategy is used to control the variable DC supercapacitor voltage. The simulation results of the STATCOM using a state-feedback with integral controller for i_d, i_q currents converter and a simple proportional (K_p) controller cascaded to d axis current loop for DC voltage source are presented and discussed.