I suggest you the three-level topology, because it offers significant advantages over the conventional two-level topology in terms of performance and efficiency. mainly an improved voltage and current ripples.
you mention only voltage regulation in your performance criteria. There are other performance issues, maximum power transfer and product life for example. During low light conditions , a buck / boost converter may be needed.
MPPT is a technique that can extract maximum power from a PV cell under cloudy conditions. Here is one paper you may find useful. http://www.sciencedirect.com/science/article/pii/S0142061512004474
The other is that converters using large electrolytic capacitors can have a short life if not designed correctly. Some inverters use multiple phase conversion to remove the need for electrolytics. Here is one example.