摘要

The paper applies a novel feed-forward control based on flatness to voltage source converter high voltage DC (HVDC) systems and demonstrates improvements in their dynamic performance. Voltage source converter HVDC plays an important role in integrating renewable energy with power grid. To confront with the unsteady nature of renewable energy, it is required to deliver better dynamic performance. In case of flatness system, a nominal feed-forward deduced from flatness and extended controller can stabilise the system around the desired trajectory. As voltage source converter HVDC is a flatness system by setting current as flat output;flatness-based control is applied with current control. Because the targets of voltage source converter HVDC are active power, reactive power, DC voltage and so on, the current reference trajectory are generated from the relations between the targets and current. To track reference well, the transition limitation of current has been taken account in the discrete-time reference trajectory. The feed-forward part of input come from the function of input and flat output, and another feedback controller is used to eliminate error. Feed-forward makes flatness-based control perform faster dynamic response than conventional dead-beat control. Finally simulation has verified the effect of the controller.

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