A Split-Phase Enhanced Hybrid Active NPC Topology for PV Applications with Short-circuit Fault Tolerant Capability

With the recent trend to utilize an optimal combination of both Si and SiC switches in a converter for cost-effective systems, the reliability of converter remains a point of concern. This paper presents a fault-tolerant Si/SiC-based hybrid active neutral point clamed (ANPC) configuration with the aim to achieve enhanced reliability for such systems with high efficiency and lower cost. The proposed converter comprises of a split-phase structure with decoupled conduction paths for positive and negative directions of load current to minimize the conduction losses and avoid the flow of circulating currents existing in such split-phase configurations. Further, the utilized split-phase structure provides protection against the short-circuit faults. This paper also proposes a novel switching scheme that enables reduction in the device losses to achieve high efficiency and reduced stress on the switching devices. Moreover, the proposed topology mitigates the issue of leakage current in the transformer-less Photovoltaic (PV) applications. In this paper, the operating principles of proposed topology with its fault-tolerant operation is described in detail. Further, analytical and simulation investigation studies are presented with the comparative investigation against the all SiC devices-based ANPC configuration. Finally, performance of the proposed converter is validated using the constructed experimental prototype.