An efficient power electronics solution for lateral multi-junction solar cell systems

Compared to a single junction solar cell, a multi-junction (MJ) solar cell can extract higher energy from sun by splitting the solar spectrum. Depending on the spectrum splitting techniques, two different structures of MJ solar cells are possible: vertical multijunction solar cell (VMJ) and lateral multijunction solar cell (LMJ). Both of these structures have their own advantages and limitations. LMJ solar cell has the potential to emerge as an effective solution for solar energy conversion although the availability of research materials on LMJ is limited compared to that of VMJ. In this paper, a complete photovoltaic (PV) power system constructed from lateral multijunction solar cells is proposed along with a new interconnection technique. The I/V characteristics of the solar cells have been matched in the proposed interconnection using a multi-input dc-dc converter. In order to ensure maximum power point (MPP) operation, particle swarm optimization algorithm is applied that requires only one maximum power point control for four solar modules resulting in cost and complexity reduction. Particle swarm optimization algorithm has the potential to track the global maxima of the system even under complex illumination situations. A complete functional system with the implementation of the proposed algorithm has been presented in this paper with relevant experimental results.