Asymmetrical DC-DC Converter with Fault Tolerant Operation Capability for Distributed Generation

As the costs of manufacturing photovoltaic (PV) panels continue to decrease, the use of PV-based solar energy systems is seen in rise across the globe. This paper proposes an asymmetrical DC-DC converter for standalone solar energy systems. The converter is developed to control modularized PV panels with a combination of soft-switching, flyback-forward, high-step-up voltage ratio, and fault tolerant operation features. This topology can achieve maximum power point tracking (MPPT) control while delivering a high voltage gain and an efficiency of 92-95% over a wide range of outputs by phase shift control. The entire system is firstly simulated and refined using the PSIM software and tested experimentally on a 300 W prototype. The key feature is its fault tolerant operation capability without the use of extra fault diagnosis circuitry. The proposed technique can be applied to grid-tied solar energy systems and fuel-cell DC systems.