Development of a 3.2MW Photovoltaic Inverter for Large-Scale PV Power Plants

The penetration of large-scale PV power plants, accompanied with the increase of the lengths of DC cables, the number of PV strings, combiner boxes, and other related equipment, have increased the conduction losses in the system. Therefore, in recent years, system DC voltage of PV plants has been increased to 1500V in order to reduce conduction losses by current passing through their components. The photovoltaic inverter rated 1500V-2.5MW had been developed in 2015. This inverter had firstly been certificated for UL certification of DC1500V photovoltaic inverter in the world in 2016. On the other hand, PV system cost required in the market is decreasing every year. Especially, the cost per output watt is attracted attention. In order to reduce its cost, larger-capacity inverter was developed in spite of using the same cabinet. This paper presents the development of a 3.2MW photovoltaic inverter with DC1500V. This inverter achieved high conversion efficiency by applying the three-level inverter topology which is a neutral point switch type, commonly known as T- type three-level inverter. The performance of the 1500V-3.2MW rated inverter was confirmed by verification.