Reduced oscillations based perturb and observe solar maximum power point tracking scheme to enhance efficacy and speed of a photovoltaic system

Abstract

Due to the solar insulation’s stochastic nature, a noticeable fluctuation in power is generated by the solar photovoltaic (PV) system. This paper puts forward a reduced oscillation based perturb and observe (ROP&O) maximum power point (MPP) tracking (MPPT) technique to mitigate the probability of loss of tracking direction and to reduce oscillations around MPP when the PV array subjected under periodically changing insolation level. The proposed technique retains the structure of conventional perturb and observe (P&O) technique additionally incorporating a unique structure of dynamic step sizing, along with proportional-integral (PI) controller which potently alter the duty cycle  of PWM gating signals applied to the DC-DC boost power converter. The ROP&O MPPT technique is compared with conventional P&O and incremental conductance (IC) schemes in terms of tracking efficacy  ripples in PV voltage and PV current, convergence time, and the error rates. The acquired simulation test results clearly indicate that the ROP&O MPPT method provides an enhanced  with reduced oscillations. The efficacy of the proposed scheme lies in between 99.06% to 99.80%. Moreover, the time to obtain an MPP is 0.018 sec. which is about five times faster than the P&O technique and fifteen times faster than the IC technique, and the time domain analysis of the proposed scheme shows a stable operation. Also, the proposed MPPT technique is benchmarked using three-phase grid integration, and the power quality of the grid current is observed in terms of total harmonic distortion (THD).