The use of microgrids for the integration of renewable energy sources and for the electric supply of rural or isolated areas involves a number of problems. One of these is reactive power sharing. Here we propose a consensus based approach to study different control strategies to achieve reactive power sharing and to numerically evaluate their performance. For that we propose a linear approximation of the microgrid power dynamics and define performance indicators based on optimization problems with LMI restrictions. These indicators are then used in a realistic simulation example to evaluate and design different consensus algorithms.