A new simple MPPT algorithm to track MPP under partial shading for solar photovoltaic systems

ABSTRACT

Extraction of electrical power from solar photovoltaic (PV) systems under nonuniform irradiance such as partial shading (PSC) or fast transient conditions (FTC) is the most challenging task for the solar PV researchers. Inaccurate detection of PSC or FTC affects the efficiency of maximum power point tracking (MPPT) algorithms. As multiple peaks are found in the P–V curve, searching of the global peak among local peaks and stabilizing the output voltage is a typical task for an MPPT algorithm during PSC or FTC. Particularly for small isolated PV systems, the output system voltage stability is of more concern than power efficiency during PSC. Here, a Modified Perturb and Observation (P&O) (MP&O) MPPT algorithm is proposed for accurate detection of PSC, which stabilizes the system output voltage without compromising with power efficiency. For accurate detection of PSC, the MP&O MPPT algorithm uses irradiance (Ir(k)) and generated PV power (P(k)) as an input parameter and regulates the step size (dD) of the boost converter duty cycle (D). A PV system is simulated in MATLAB/Simulink and the performance of the proposed algorithm is also investigated using dSPACE controller, solar PV emulator and a SiC Mosfet switch under PSC. The accuracy to detect PSC or FTC of this algorithm is found satisfactory with fast tracking speed.

KEYWORDS:

• Solar PV
• MPPT
• partial shading
• fast transient
• energy loss calculation

Acknowledgment

This work was supported in part by Visvesvaraya PhD scheme by the Department of Electronics and Information Technology (DeitY) Government of India being implemented by Digital India Corporation formally Media Lab Asia.