Table 1: Comparison of control strategies.

AdvantagesDisadvantagesTechniques

VCRealizing easily; no special requirements for hardware and softwareCausing coupling between two sets of the windingsGenerating the current control signals using the feedback and coordinate transformation
ICAchieving IC of radial suspension force, and hence improving the flexibility of torque control schemeRequiring additional magnetic flux observerObtaining the torque winding flux linage dependently
DTCFast torque response; less parameter dependence; no need for current controlCausing errors due to variation of stator resistance and drift in flux linkage estimationGenerating the voltage vectors using independent torque and flux computations
NDCFlexible control algorithms; adapting nonlinear theories and parameter variationsRequiring sophisticated hardware and intensive computation or experiential knowledgeTaking advantage of neural network or other nonlinear theory
SCRemoving the mechanical sensors, and hence reducing the system cost and size; readily merging into other controlsRequiring sophisticated hardware and intensive computationEstimating the position and displacement based on the motor mutual inductance