A New Direct Power Control P&O Method (PMPPT) for Standalone Photovoltaic Applications

This paper proposes a pivotal approach to extract the maximum PV power by the direct control of load power using the same P&O concept which is traditionally used to generate the duty cycle of the downstream dc-dc converter. As the dc-dc converter is not used by the P&O algorithm, it is utilized to control the inverter dc-link voltage. This proposed new configuration is called Direct Power-MPPT (PMPPT). The proposed PMPPT provides the per unit power reference to the power controller which directly generates the reference modulation index to the inverter PWM modulator. The PV load is presented by RL load supplied from a Three-Level Neutral-Point Clamped inverter (3L-NPC). The technique overcomes a trade-off between the speed of tracking and obtaining high efficiency. The effectiveness of the proposed control strategy is verified by simulation under various disturbances and operating points conditions. The simulation and experimental results demonstrate and verify the capability of the proposed PMPPT to track the maximum power accurately under all test conditions.