A Novel Sensorless Photovoltaic Power Reserve Control With Simple Real-Time MPP Estimation

Power reserve control (PRC) without energy storage becomes essential for modern photovoltaic (PV) power plants to meet the increased ancillary service requirements such as grid frequency support. Conventional PRC strategies show obvious limitations to estimate the available maximum power point (Pavai), such as additional hardware requirements, implementation difficulty, and slow estimation speed. Originated from the linear characteristic of PV curves in the constant current region and a Lambert-W function for voltage linear reference, P
_avai
is estimated separately in separate steps rather directly measured or estimated. The proposed strategy does not requires any additional hardware such as the irradiance and temperature sensors, which realizes sensorless control with reduced cost. Furthermore, cumbersome procedures of curve fitting with sophisticated operating points sampling and key parameters determination in the real-time P
_avai
estimation by using the conventional PRC methods can be also eliminated. In this strategy, the operating point with a curtailed power level is allocated at the left-hand side of the MPP, which guarantees the stability of PV systems under varying conditions. The developed strategy exhibits fast speed to estimate P
_avai
, high robustness, and good compatibility with existing PV systems. Simulation and experimental results under various scenarios are provided to validate the effectiveness of the proposed strategy.