A method for instantaneous measurement of PV V-I characteristics and its application for MPPT control

A method for instantaneous measurement of PV V-I characteristic has been proposed. In the method, the PV electric load is instantaneously switched from open-circuit into short-circuit and then back into open-circuit with a semiconductor switch, and the PV V-I characteristics is obtained by using the transient PV voltage and current measured during the two switching processes. Several experiments with different types of PV have verified the proposed method. The proposed method can be used not only for on-line diagnosis of PV systems but for PV maximum power point tracking (MPPT) control. As an example to demonstrate the applications, experiments of PV MPPT control has been performed and expected results have been achieved.