Small Signal Model for PV Fed Boost Converter in Continuous and Discontinuous Conduction Modes

Small signal models are of high importance in power electronic systems which exhibit highly non-linear properties. They provide access to stability and help in tuning controllers. Small signal models for many power electronic converters are seen in the literature. However, specific applications like photovoltaic systems demand the addition of a capacitor at the terminals of photovoltaic (PV) panel. Since this capacitor is connected between the PV panel terminals and the input of power converter, it is termed as input capacitor. The effect of the addition of input capacitor on system stability has not been addressed yet. In this brief, we derive the small signal models for PV fed boost converter operating in both continuous conduction mode (CCM) and discontinuous conduction modes (DCM) of operation. The load is assumed as purely resistive; however, the analysis holds good for any practical loads. It is observed that in both CCM and DCM the stability of the maximum power point tracking (MPPT) system is independent of the input capacitance. It is also shown that the MPPT system is open loop stable for all operating conditions. The studied models are further validated with the experimental setup.