This paper presents a new method for voltage analysis for islanded microgrids using the energy function method and a new technique based on an auxiliary function to allocate intermittent sources. The energy function allows the direct stability evaluation of the system operating points, taking into account the variation of loads, the intermittence of the photovoltaic, and the charging/discharging of energy storage systems under pre-defined conditions. The auxiliary function is applied as a planning tool, defining the weak system areas, where photovoltaics and energy storage systems can be allocated. The results show the voltage stability assessment's effectiveness using the energy function and the improvement of the system stability condition when allocating the intermittent sources in the microgrid area indicated by the auxiliary function technique.
