A global non-linear model of the excitation loop dynamics of a synchronous generator has been constructed from five second-order ARX sub-models and their normalised Gaussian validity functions. Each identified local model was then used for Generalised Minimum Variance (GMV) control design, with the individual outputs weighted by the corresponding model validity functions and summed for overall control. The resultant multiple controller was successfully implemented for automatic voltage regulation (AVR) on a laboratory micro-machine. Encouraging experimental responses to a three-phase short circuit were obtained compared to a conventional fixed-gain AVR.