Active Disturbance Rejection Control for DC/DC Converters in MTDC Systems

In this paper we demonstrate theoretically the stability of MTDC systems with multiple ADRC-controlled converters. In particular, the ADRC model, consisting of a linear quadratic Gaussian (LQG) structure with reference trajectory generator, is applied for the voltage regulation of the DC/DC source-side converters in MTDC systems. Small-signal stability analysis demonstrates the ability of the local ADRC converter controllers to estimate and track the system dynamics, cancel internal and external disturbances and thus stabilise the system. The stability analysis shows theoretically the robustness of the ADRC model to uncertain load and converter models, and the ability to mitigate different interactions in the system. Time domain simulations show the ability of the linear ADRC model to deal with the non-linearities of the MTDC systems. Finally, experimental results demonstrate the easy hardware implementation of the ADRC model for the voltage regulation of DC/DC converters, and its ability to track the system dynamics fast and accurately for the tight DC voltage regulation.