A Photovoltaic-Based Novel Transformerless High Gain Converter for DC Microgrid Applications

A typical microgrid network sourced by renewable energy encounters a technical setback owing to the voltage imbalance across the source integration and load power dissemination. Transformers employed to stabilize the potential may deteriorate the network efficiency and increases the cost and size of the system as well. Photovoltaic based transformerless high gain DC-DC converter (THG-DC) is proposed here to aid the microgrid infrastructure. Microgrid fuelled by renewable energy sources demands the high gain converter interface to boost low voltage generation. The proposed THG-DC is employed with four switched inductors and three active power switches (IGBT) which are brought together under dual leg configurations. The proposed topology offers dual-duty cycle modes of regulating the active switches to realize the desired output voltage. Moreover, it is reliable to drive the proposed THG-DC with lower values of duty cycles to achieve a higher gain. The voltage stress across the switches is minimized and the magnitude of inductor current ripples is quashed to an extent. The proposed THG-DC is simple in architecture and easy to control in all three operating modes. The operating characteristics and performance investigation of the novel converter during the continuous and discontinuous modes are elucidated briefly and the comparative analysis on switching stress, gain, and efficiency are executed to justify the standards of the proposed THG-DC. Finally, the miniature prototype model is experimented with in the laboratory (0.3 kW) and the obtained results are in agreement with the theory. It is evident from the investigations that the proposed THG-DC shows its dominance over other converters on the voltage gain, switching stress, number of components, and overall efficiency.