Pl. Jansen et al., OBSERVER-BASED DIRECT FIELD ORIENTATION - ANALYSIS AND COMPARISON OF ALTERNATIVE METHODS, IEEE transactions on industry applications, 30(4), 1994, pp. 945-953
This paper focuses on methods of achieving direct field orientation (D
FO) of induction machines based on closed-loop, stator, and rotor flux
observers which are well suited to both zero and very high-speed oper
ation. Both observer topologies are dominated by a current model at ze
ro and low speeds, and a voltage model at high speeds. Application of
such rotor and stator flux observers to both stator and rotor direct f
ield orientation is presented, including experimental results for thre
e different methods. The influence which flux regulation has on parame
ter sensitivity of the complete DFO system is analyzed. A rotor-flux-r
egulated and -oriented system is shown to be sensitive to leakage indu
ctance under high slip (i.e., field weakened) operation. Both a stator
-flux-regulated and -oriented system and a stator-flux-regulated, roto
r-flux-oriented system are shown to have reduced parameter sensitivity
at high speeds. Unlike stator flux orientation using simple voltage i
ntegration stator flux models, excellent zero and low-speed operation
of an observer-based stator-flux-oriented system is demonstrated.