Phase shifted maximum power point tracking in a cascaded H-Bridge photovoltaic power system

Multilevel Cascaded H-Bridge (CHB) converters have attractive features for the implementation of large scale photovoltaic systems. They can be directly connected to high voltages and the multilevel voltage synthesis reduces the harmonic distortion introduced. In addition, they have individual DC links ideal for connecting photovoltaic arrays. Existing high performance voltage balancing techniques can also be adapted to integrate Maximum Power Point Tracking (MPPT). This paper considers the impact of Perturb and Observe Maximum Power Point Tracking on the performance of a 19 level three phase CHB converter and proposes the new method of Phase Shifted Perturb and Observe Maximum Power Point Tracking.