ACTIVE POWER CONTROL IN PV SYSTEMS BASED ON A QUADRATIC CURVE FITTING ALGORITHM FOR THE MPP ESTIMATION

摘要

In this paper, an active power control strategy is presented in order for a PV plant to operate at a specified suboptimal output power setpoint and maintain power reserves, expressed as a fraction of the maximum available power. Given that the latter is not known a priori, a quadratic curve fitting algorithm is applied to recent past measurements in order to estimate the P- V curve and calculate the operating voltage to achieve the desired power reserve levels. The proposed method offers sufficient accuracy, increased robustness and computational efficiency, combined with excellent dynamic response at irradiance variations and reserve command changes. The effectiveness of the control strategy and the P- V curve estimation method is validated by simulations in MATLAB/Simulink.