DC-DC converters with constant power loads are mostly used in DC microgrids. Negative impedance and large disturbances of constant power loads may lead to the instability of DC-DC converters. To address this issue, a nonlinear control strategy consisting of an improved passivity-based controller and nonlinear power observer is proposed in this paper. First, an improved passivity-based controller is designed based on the port-controlled Hamiltonian with dissipation model. By proper damping and interconnection injecting, the fast dynamic response of output voltage and stability of the DC-DC converter is achieved. Second, the constant power load is observed by a nonlinear power observer, which is adopted to estimate the power variation of the constant power load within a small settling time and improve the adaptability of the DC-DC converter under power disturbance. Finally, the simulation and experimental results are presented, which illustrate the proposed control strategy not only ensures the stability of the DC-DC converter under large disturbances, but also can track the desired operating point with low voltage overshoot in no more than 10 milliseconds.
CITATION STYLE
Wang, M., Tang, F., Wu, X., Niu, J., Zhang, Y., & Wang, J. (2021). A nonlinear control strategy for dc-dc converter with unknown constant power load using damping and interconnection injecting. Energies, 14(11). https://doi.org/10.3390/en14113031
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