Analysis of nonlinear control for high power arc heater utilizing thyristor converter

The paper proposes and analyses a nonlinear control strategy for high power arc heater utilizing thyristor converter. Because of the nonlinear negative v-i characteristic of arc, a nonlinear feed-back controller and a feed-forward controller are combined to regulate the arc current. The nonlinear feed-back controller, cascading the special nonlinear function of error on the classical PI regulator, counteracts possible disturbances in the current loop. The feed-forward controller guarantees the exact control in absence of external disturbances. This nonlinear control strategy has better performance than classical PI control, and it is simpler than artificial neural network control. It is also robust against the load uncertainty. Simulation and experimental results are provided to verify the validity of the proposed control strategy.