Effects of the shape of compressor characteristics on actuator requirements for rotating stall control

We present a systematic analysis on the effects of noise, the shape of compressor characteristics, and bleed valve actuator limits on the performance of controllers in rotating stall control. We use center manifold reduction to the three state Moore Greitzer model with piecewise analytic compressor characteristics. For the reduced system, the optimal control which achieves the largest operability enhancement is the "bang-on" control law that drives the valve to open against its rate limit. For the optimal controller, we also derive approximate formulas for the operability enhancement as a function of the noise level, the actuator limits, and the shape of compressor characteristics. The predictions by the formulas are compared with numerical simulations using a model for a low speed axial compressor.