Robust regulation of the air distribution into an arc heater

The paper deals with the problem of regulating both the air total mass flow rate and its distribution in a 70 MW constricted-segmented electric arc heater by means of a five way air supply system. Firstly a description of the detailed dynamic model of the pneumatic process, obtained in the lumped parameter domain, is provided; then the control strategy is described. In order to guarantee the desired distribution of the total air supplied along the arc heater, a multiple PI control technique is proposed to command five partitioning valves. A physical reduction of the plant model leads to five decoupled linear parameter varying first order systems. For each of them a PI controller is designed. A robust synthesis which makes use of the concept of quadratic stability with a fixed decay rate and with an H∞ norm bound is proposed to cope with uncertainties, nonlinearities and disturbances. Numerical simulations are carried out to show the effectiveness of the control technique.