Abstract – The aim of this paper is to present a new fuzzycontrol scheme for real time drive efficiency improvement by
the adaptive flux reduction at light loads during steady states and by the optimum flux recovery during transient states. The
optimum flux recovery instead of the rated flux does not sacrifice the drive dynamic response since the torque capacity
remains the same and accelerates the search convergence in steady states. The control scheme is cooperated with an
Indirect-Field-Oriented-Control (IFOC) motor drive. The design of the new fuzzy control scheme is focused to recognize
the motor state operation in order to control under the corresponding circumstances. The proposed fuzzy control
scheme includes three main units: one Fuzzy-Logic-Search Controller FLSC1, one Fuzzy-Logic-Controller FLC2 and a
State detector unit. The State detector unit decides which of the FLSC1 or FLC2 controllers is used, in accordance to the
operation circumstances. The fuzzy controllers utilize the stator flux-producing current component into d-q reference frame
(stator current direct axis i) as control variable, in order to estimate the next optimal change of Δi
sd.
The drive efficiency improvement and the drive dynamic response is currently validated in laboratory using an experimental array of a 3phase 1 Hp induction motordrive.Thecontrol scheme is implemented using the platform eZdsp from Digital
Spectrum based on the fixed point 32 bit DSP TMS 32 0F2812 from TI.