Single Integration for Multi-objective Control

The saturation issue with paralleled PI controllers in multi-objective control is investigated. Dual-Active-Bridge (DAB) enabled DC micro-grid stabilization is chosen as a case study. The DAB converter has two control objectives: battery current regulation and the DC bus voltage stabilization. The conventional approach draws on two paralleled independent PI controllers for battery current regulation and DC bus stabilization. The output of the stabilization PI controller presents arbitrary values in the steady state. As a consequence, the saturation of the PI controllers may happen and can largely deteriorate the control performance. To address this issue, a simple but effective technique termed as single integration is proposed. The proposed method utilizes two linked controllers which share their integration value. Simulations and experiments on a 270V-270V, 20kHz, 1kW DAB converter are conducted to verify the theoretical claims.