PARAMETER-IDENTIFICATION OF COMPRESSOR DYNAMICS DURING CLOSED-LOOP OPERATION

A low-speed axial research compressor has been fitted with movable inl et guide vanes to allow for feedback stabilization of rotating stall. A model exists whose structure captures the input-output behavior, and stabilization of rotating stall is possible using this model. Quantit ative identification of the parameters in the rotating stall model req uires the ability to identify MIMO dynamics, which may be unstable, du ring closed loop operation. The 'instrumental variable' technique is p resented as the basic approach to this problem. The necessary extensio ns to the basic technique are discussed, and the resulting algorithm i s applied. Experimental results are presented which verify that the me thodology yields useful estimates.