Water level control of U-tube steam generator based on model-based active disturbance rejection control method

•A model-based nonlinear ADRC control system is proposed for steam generator water level control.•The Irving model is utilized to establish the ESO to estimate the disturbance of SG.•The genetic algorithm is applied to tune the parameters of nonlinear ADRC.•The model-based nonlinear ADRC is proven to have a better control performance. Steam generator (SG) is an important equipment of pressurized water reactor, which has the characteristics of strong nonlinear, non-minimum phase, time-varying, and large delay. Therefore, designing an SG water level control system with good control performance and strong disturbance rejection ability is necessary. In this paper, the nonlinear dynamic model equations of SG are derived based on basic conservation equations. A nonlinear model-based active disturbance rejection controller (ADRC), a simple and separable control algorithm with strong disturbance rejection and robustness, is proposed for SG water level control. An extended state observer containing model information is established based on the Irving model. A genetic algorithm tunes the ADRC controller parameters. The control performance is verified by introducing the water level setpoint step and ramp disturbances and steam flow rate step disturbance. The simulation results show that the ADRC controller of SG water level has good control performance and disturbance rejection ability.