Fast Maximum-Power-Point-Tracking for Photovoltaic Systems Based on P-V²Characteristic Curve and Its Stability Analysis

To increase the tracking speed of the photovoltaic system (PV) for dynamic efficiency enhancement, a Maximum-Power-Point-Tracking (MPPT) method based on the P-V2 curve is proposed. In contrast to the traditional design of MPPTs, it is demonstrated that the sampling frequency of MPPT can be increased to achieve an even faster dynamic than the settling time of the dc-voltage control loop as long as the closed-loop MPPT is still stable. Response time of the proposed P-V2 based MPPT can be designed with a much faster dynamic than the conventional MPPT methods while its stability is guaranteed because i) adopting the squared PV voltage makes the dc-voltage control loop linear, and ii) the whole MPPT system conforms to the Lure's systems whose stability can be rigorously analyzed to obtain design guidelines for stable MPPT. Theoretical results are verified by simulation on Matlab/Simulink.