Microgrid with Five-Level Diode Clamped Inverter Based Hybrid Generation System

This paper presents a new architecture for standalone microgrids incorporating 5-level diode clamped inverter (DCI) for interfacing hybrid generation system (HGS) with ac loads. The HGS involves photovoltaic (PV) arrays, battery packs and diesel generator (DG) that act as individual dc sources for DCI which in turn eliminates the need of input capacitors for DCI and the associated voltage balancing. For the DCI output voltage level of 2V
_dc
, the DG and the combination of PV array and/or battery supply the load. Similarly, the PV array and/or battery feed the load when the voltage level is V
_dc
. Likewise, for the levels -V
_dc
and -2V
_dc
, a separate PV array, battery pack and DG are operated in similar manner. In case the PV power is greater than the demand, it can be used to charge the battery. Conversely, if the PV power cannot meet the demand, then the charged battery pack can assist to feed the load. The system reliability and selfsustenance capability is enhanced with the use of DG. Additionally, as no synchronization with the DG is required, the need of fundamental current extraction is eliminated. The operation of the proposed standalone microgrids with 5-level DCI based HGS is analysed for different operating conditions.