CASCADED RENEWABLE ENERGY SOURCES IN TANDEM WITH STORAGE SUPPORT FOR CURBING INTERMITTENCY IN GRID TIED OPERATION

Abstract

With depleting fossil fuel and threats for environmental hazards, the energy generation is witnessing a shift towards renewable energy sources(RES) globally. Such inclination towards the RES could only become possible due to advancement in power electronics and faster digital controller. Low capacity RES are connected to LV distribution system which offer low power capacity. Such low capacity system are vulnerable to problem of voltage regualtion caused by intermittency of power injection by RES in the weak system. The onslaught from the load perturbance can be gradually reduced if the RES are integrated to high capacity microgrids at higher voltage in distribution syste, since the are meant for bulk power transfer and there exist very bleak possibility of current reversed. Therefore to the great extent problem of voltage regulation is subscribed. The source side intermittency is mitigated by storage support, which become costly if dealt as Battery energy storage system(BESS) connected in shunt with load and RES, being interfaced to higher voltage. A cascade connection of RES with differential voltage support by the battery is proposed in the thesis for curbing the intermittency in the sources and enabling the connection of the proposed configuration to higher voltages. A bi-directional interface for battery is solicitated for incorporation, which is enabled though DAB, with high frequency isolation transformer providing the necessary boost in the voltage. The thesis has dealt with the design of high frequency isolation transformer and same is validated through simulation results when connected with DAB. The developed control algorithm for bi-directional control of DAB is also tested under MATLAB/Simulink environment for variable duty cycle control for requisite power. The results demonstrated the effectiveness of control and validate the analytic value through simulated results.