Solar dish-Stirling system optimisation with a doubly fed induction generator

A handful of dish-Stirling system designs, comprising different solar concentrators and Stirling engine/generators, are currently and successfully demonstrating the technical feasibility of solar power generation for extended periods of time. Most designs focus on concentrators and engines obtaining a high performance while remaining robust. The systems achieve power control by varying gas pressure or engine volume. This study shows how to optimise the power generation of grid connected dish-Stirling systems by varying the Stirling engine speed when coupling it to a doubly fed induction generator (DFIG). The proposed control system for DFIG is direct power control, which performs the tracking of the maximum power point within the Stirling engine characteristic.