Control of Interleaved Converters with Constant Power Load for DC Microgrid Application

In dc microgrid application, the tightly controlled power electronic load behaves as a constant power load. It features negative incremental impedance and tends to destabilize the dc bus. To better deal with the stability issue, in this paper, a robust dual-loop controller is proposed and applied to the interleaved converters with constant power load. The inductor current inner-loop based on super-twisting algorithm is used to fast track the reference generated from the outer-loop. The energy outer-loop uses the extended state observer (ESO) to estimate in real-time the total disturbance (including the modeling imperfection, and external disturbance), which is then canceled in the control law. The proposed method shows good robustness, and its global stability is proved theoretically. The extension of the proposed method to the system with multiple converters is given as well. Finally, the simulation results validate the effectiveness and robustness of the proposed controller.