Dual implementation of the MPPT technique TEODI: Uniform and mismatching operating conditions

In this paper the dual implementation of the MPPT technique TEODI is presented and discussed. Such a new technique will be called D-TEODI. As well as TEODI, also D-TEODI is suitable for DMPPT PV applications. Its main advantages, as for TEODI, are the simplicity of implementation, the absence of memory and multiplication operations, and the high MPPT efficiency obtainable when the PV modules belonging to the same TEODI Building Block operate in the same atmospheric conditions (absence of mismatching conditions). In order to obtain a technique which is efficient also when mismatching events occur, a proper modification of D-TEODI is necessary. The modified version of D-TEODI will be called MD-TEODI. MD-TEODI is based on the periodic measurement of the short circuit currents of the PV modules. The knowledge of such currents allows not only to determine if mismatching conditions have occurred, but also to identify a suitable correction factor k on which the working of MD-TEODI is based. The results of numerical simulations fully confirm the validity of MD-TEODI.