Nanogrid for Home Application for Micro CHP based on Free Piston Stirling Engine

The paper concerns on a micro Combined Heat and Power system based on Free Piston Stirling Engine (μCHP-FPSE) as prime mover for linear synchronous generator. One of the main problems related with this system is the need of a stable grid connection. Voltage sags or swells are a huge problem, at same way the discontinuity of the heating service in case of blackout as briefly described in the paper. Moreover, the μCHP-FPSE is generally characterized by high purchase costs that increase if a dedicated grid interface converter system is used to overcome the above-mentioned problems. To overcome the drawback caused by the above-mentioned problems and at the same time to reduce the purchase costs, the use of a Nanogrid for Home Application is proposed. The considered Nanogrid for Home Application consists of several converters, which are suitably controlled and interfaced to optimal manage the power flows. The operation of the Nanogrid is based on the use of an IGBT integrated intelligent power module, the related gate drivers and cooling technology in a set-up. This set-up realizes a compact hybrid system that integrate all in one a photovoltaic generator, a storage system, a μCHP-FPSE and a UPS system to supply uninterruptible loads.In the paper, after a brief description of the μCHP-FPSE behaviour, the Nanogrid, its possible configurations and the high costs of the μCHP-FPSE are analysed; then the optimal design of the whole system, considering the integration and interfacing of the μCHP-FPSE using the Nanogrid for Home Application is carried out. Finally, laboratory tests performed on a pre-industrial prototype are presented and discussed.