Modelling of small signals in MISO DC-DC converters for hybrid energy sources

Smart-grid systems are based on the integration of renewable energy based micro-grid with the main utility grid, using an interlinking inverter between a constant voltage DC bus and grid side AC bus. This paper explores the design method of MISO" (Multiple Input Single Output) and "DISO" (Dual Input Single Output) DC-DC converters fed with solar photovoltaic (SPV) system and wind energy conversion system (WECS). Both the converters have been integrated to a common DC link. In this regard a Cuk converter and SEPIC converter have been integrated. A large signal model and a small signal model of the integrated converter have been developed. At first, a state space-based model is developed for the entire system. In the next step, transfer functions are developed between the common output voltage and various inputs to the system. These transfer functions are used to obtain various time domain parameters. In the end, a hardware prototype of 1 kW converter unit has been developed using D-Space 1104 to validate the mathematical model of the power converter topology and accuracy of the developed transfer function.