IDB Convertor – An international maximum power extractor for PV-supplied DC motor system

The Photovoltaic (PV) generator exhibits a non-linear v–i characteristics and its maximum power point varies with insolation. For optimum matching of PV generator and motor load, an intermediate Interleaved Dual Boost converter is employed. Its effectiveness as an intermediate maximum power extractor for PV-supplied and separately excited DC motor is studied through simulation. Extensive studies are made by formulating the mathematical models for PV source, Boost/Interleaved Dual Boost converter, DC motor and load. For determination of maximum power points at different solar insolations, a closed form solution technique is employed, which avoids tedious and time-consuming iterative methods. The Boost/IDB converter duty ratio variation with insolation is determined and steady-state performance of the motor coupled to centrifugal pump load is analyzed for maximum power operation. From the simulation studies it is found that the motor performance is improved with IDB converter compared to conventional boost converter. Furthermore, the use of IDB converter reduces the ripple content both in the source and load waveforms, thus resulting in reduced filtering requirements and improved PV array performance.