An accurate MPPT scheme for photovoltaic modular-based conversion units: A robust sensorless predictive approach

Abstract

This research presents a Maximum Power Point Tracking (MPPT) algorithm for a solar photovoltaic (PV) power station which is constructed based on modified circuit topology of the Modular Multilevel Converter (MMC). The proposed MPPT is featured with Optimized Finite-Control-Set Model Predictive Control (FCS-MPC) to provide continuous extraction of maximum solar energy. The estimation-based approach allows for elimination of the current sensors in PV panels unlike the well-proven MPPT methods, e.g., perturb and observe (P&O) and ripple-correlation control (RCC), where costly sensing devices are widely deployed. With developed control strategy, fast tracking response for the PV plant along with acceptable control bandwidth under solar irradiation transients and PV panels mismatch are achieved. The introduced circuit of power conversion has led to decreased number of solar cells and a 50% reduction of the energy storage sizing compared to the basic MMC configuration. The effectiveness of the discussed MPPT solution over the solar irradiance variations is compared with the both P&O and RCC methods. The behavior of the studied PV system is also evaluated under different operational scenarios through simulations to confirm the designed concept.