Photovoltaic model and converter topology considerations for MPPT purposes

Abstract In this paper a few variations of the single diode photovoltaic (PV) model are developed by removing the series and/or parallel resistors. The models are expected to yield similar results due to the large parallel resistance and small series resistance. Nonetheless, the IV and power curves are compared. The models are then compared in the context of different converter systems. If the behavior is similar, then one may be justified in analyzing Maximum Power Point Tracking (MPPT) systems by using a simpler PV model than that normally used. In particular the single diode model with no resistors allows the current (or voltage) to be explicitly defined in terms of the voltage (or current), whereas the model using two resistors does not. The different converter topologies were also compared for each model to see if the dynamic behavior of the PV system depended on the converter used. For the most part the results were fairly consistent regardless of the PV model, PV module, or converter used. For example, low voltages on the IV curve yielded non-constant steady state behavior for all system configurations. However, there were some inconsistencies which could be worth further consideration, as they may affect the design of the MPPT algorithm.