A duty cycle optimization based hybrid maximum power point tracking technique for photovoltaic systems

Abstract

Photovoltaic (PV) energy has witnessed tremendous growth in the recent past. PV system exhibits the IV curve, which varies non-linearly according to immediate weather conditions. Maximum power point tracking (MPPT) technique is an essential part of PV system which tracks the unique maximum power point (MPP) on its IV curve. In this paper, a new MPPT is proposed which is equipped with duty cycle (D) optimization method. The proposed method works in three stages containing hybrid mechanism of two basic techniques i.e. perturb & observe (P&O) and fractional open-circuit voltage (FOCV). D-optimization scheme enhances the performance of the proposed technique under varying weather conditions compared to past MPPTs. While hybrid mechanism helps the technique to quickly focus the MPP with negligible power loss oscillations under steady weather conditions. For stable operation of MPPT algorithm, instrumentation and measurement issues of PV system have been addressed. A new evaluation criteria is proposed for MPPT algorithms. Finally, the proposed MPPT and other techniques have been simulated in Matlab/Simulink under various weather conditions. Simulation analysis confirms the superior performance of the proposed algorithm compared to other MPPTs. The evaluation criteria reveals that the PV array operates at an efficiency of 99.9% under steady conditions while under dynamic weather conditions the operational efficiency of the PV array is always in excess of 90% with the aid of the proposed technique.