A New Voltage Clamp Method for PV Maximum Power Tracking Under Shading Conditions

In this paper, a novel Voltage Clamp Method (VCM) for Maximum Power Point Tracking (MPPT) of a partially shaded PV string conventional structures is presented. In the proposed approach, clamp voltages are imposed on the PV array to measure the available currents of each panel. This allows the detection of the shading situations and the estimation of the optimal power profile. The clamp voltages are precisely generated by a switched electronic circuit that behaves as a variable Zenerdiode. This circuit is implemented by a digitally controlled closed-loop amplifier that is capable of handling high currents and high voltage. The suggested technique is evaluated by both simulations and experimental tests where various dynamic irradiance conditions have been considered. Our system is easy to implement since it does not require either irradiance, temperature sensors, extensive modeling, complex calculations, or an expensive setup.