A Robust LESO-based DC-Link Voltage Controller for Variable Speed Hydro-Electric Plants

Variable speed technique can improve the hydraulic power profitability and optimise the hydraulic transient process. Permanent magnet synchronous generator equipped with power electronics are widely implemented in the hydraulic context. The robust and efficient control of the DC-link voltage is important in the energy conversion process. However, the DC-link control stability is negatively affected in the presence of hydraulic power variations and various disturbances. In this paper, a Linear Extended State Observer (LESO)-based DC-link voltage controller is implemented in a variable speed hydro-electric plant. Comparative experiments with well-tuned PI controllers are conducted, the results prove its higher robustness and disturbance rejection ability under varying hydraulic conditions.