This paper presents a modification to the generalized predictive control algorithm which guarantees closed-loop stability. The GPC controller is designed using a terminal equality constraint. The available degrees of freedom are presented to the designer as parameters called principal components. This components can be left or removed from the solution to get different performances. Two methods to select the degrees of freedom are presented based on percentage of index minimized and control effort applied to the process respectively. This methods can be an alternative to the empirical selection of the weighting control factor lambda.