Reduced-order flux observers with arbitrary convergence rate

This paper describes a method of designing reduced-order observers in the space-phasor flux description of the induction machine. By making use of the second-order complex model of the induction machine, two reduced-order observer structures with time-invariant feedback gains are derived and shown to possess arbitrary convergence rate. Experimental runs facilitate comparison of the suggested reduced-order observers with the well-known full-order time-variant feedback gain observer