Control of wind diesel hybrid system with bess for optimal operation

This paper presents the design and control of wind diesel hybrid system feeding 3-phase 4-wire distribution network. The grid is energized by conventional diesel generators. Wind energy block consists of a wind turbine coupled to DFIG (Double Fed Induction Generator) equipped with MPPT (Maximum Power Point Tracking). The MPPT demands regulation of the turbine speed which is realized with the help of rotor side converter. The DFIG control consists of two voltage source converters connected back to back at DC bus with a battery bank. The control system is designed such that the loading of diesel generator(s) remains in optimum loading condition keeping currents of wind generator as well as diesel generators balanced. Any surplus or deficient energy is circulated through a battery bank connected to the DC side of both converters. The complete system is modeled using Simpowersystem tool box of MATLAB 7.10 and its results are presented for conditions such as synchronisation of wind generator, load variation, nonlinear load and unbalanced load, varying wind speed etc. Under all the above conditions, the currents flowing through DFIG and diesel generators are balanced.