Multidimensional Ripple Correlation Technique for Optimal Operation of Triple Active-Bridge Converters

The paper presents a multidimensional ripple correlation search technique of optimal operating points of triple active bridge (TAB) converters. Such converters present multiple modulation parameters that should be exploited to achieve high operation efficiency. On the other hand, the several degrees of freedom available make the identification of optimal parameters a challenging task, not easily tackled analytically or in closed form. A model-free on-line search method based on the ripple correlation technique is then proposed in this paper. The proposed method finds the optimum modulation parameters of TAB converters utilizing a three-dimensional ripple correlation control. The key property of the proposed solution is the adoption of orthogonal perturbation signals, where the orthogonality is simply obtained using different injection frequencies. The multidimensional correlation technique originally shown herein can be applied to other generic optimization problems. The proposed search is verified through a hardware-in-the-loop validation setup and an experimental prototype rated $5kW$.