Abstract: In order to improve the robustness of DCDC converters with disturbances and uncertainties， a robust PID control algorithm was proposed on the basis of the linear matrix inequality (LMI). The PID parameters were tuned by the regional pole assignment(RPA). Taking into account the controlled system robustness against disturbances， the H∞ control was combined with PID control， and solvability condition for the existence of H∞ PID controller was derived in the form of LMI. The designed controller is such that the closedloop system poles are assigned in a specific region in order to obtain anticipant dynamical characteristics， and the closedloop system has an H∞ disturbance attenuation upper bound. Further， the proposed design method can be applied to the DCDC converters with polytopic uncertain parameters. The simulation results of both certain model and uncertain model of buck converters demonstrated the validity and effectiveness of the proposed control strategy.

Key words: PID control, regional pole assignment(RPA), H∞ control, linear matrix inequality(LMI), DCDC converter