Input characteristic impedance technique of power converters circuits applied to the maximum power point tracker of photovoltaic panels

In this paper a maximum power point tracker (MPPT) method for photovoltaic (PV) panels using the input characteristic impedance (ICI) of power circuits is presented. The proposed MPPT algorithm employs just a single voltage sensor. Although the input impedance theoretically depends on its load resistance, it is shown that using the proposed algorithm the maximum available PV power is obtained without previous knowledge of the load resistance value. This technique can be applied to any dc-dc power converter circuit, mainly to the basic dc-dc converters as: Buck, Boost, Buck-Boost, Cúk, SEPIC, and Zeta. To validate the proposal method the Zeta power converter circuit was chosen.