The Novel Rotor Flux Estimation Scheme Based on the Induction Motor Mathematical Model Including Rotor Deep-Bar Effect

Abstract

During torque transients, rotor electromagnetic parameters of an induction motor (IM) vary due to the rotor deep-bar effect. The accurate representation of rotor electromagnetic parameter variability by an adopted IM mathematical model is crucial for a precise estimation of the rotor flux space vector. An imprecise estimation of the rotor flux phase angle leads to incorrect decoupling of electromagnetic torque control and rotor flux amplitude regulation which in turn, causes deterioration in field-oriented control of IM drives. Variability of rotor electromagnetic parameters resulting from the rotor deep-bar effect can be modeled by the IM mathematical model with rotor multi-loop representation. This paper presents a study leading to define the unique rotor flux space vector on the basis of the IM mathematical model with rotor two-terminal network representation. The novel rotor flux estimation scheme was validated with the laboratory test bench employing the IM of type Sg 132S-4 with two variants of rotor construction: a squirrel-cage rotor and a solid rotor manufactured from magnetic material S235JR. The accuracy verification of the rotor flux estimation was performed in a slip frequency range corresponding to the IM load adjustment range up to 1.30 of the stator rated current. This study proved the correct operation of the developed rotor flux estimation scheme and its robustness against electromagnetic parameter variability resulting from the rotor deep-bar effect in the considered slip frequency range.

Ripple Attenuation for Induction Motor Finite Control Set Model Predictive Torque Control Using Novel Fuzzy Adaptive Techniques

“…Therefore, a current-type observer is adopted in this paper. As in [39], according to (1)-( 5) and the flux descriptions, the rotor flux can be derived as,…”

A Dynamic Model for Saturated Induction Machines With Closed Rotor Slots and Deep Bars

“…The rotor-side impedance can be measured by completing a series of locked-rotor tests, where the stator current magnitude is kept constant and the stator angular frequency ω s is varied. For each angular frequency, the rotor-side impedanceZ is definedZ = − jω sψs i r (11) where the stator flux linkage is calculated using (9). The rotor current is calculated as…”

“…This phenomenon is called a deep-bar effect. The deep-bar effect can be included in space-vector models by means of resistor-inductor ladder circuits [7]- [11], which further can be represented in the form of a transfer function [12]. The ladder circuits in [8]- [11] are based on the multicage rotor structure, and they are parametrized by means of numerical optimization.…”

“…The deep-bar effect can be included in space-vector models by means of resistor-inductor ladder circuits [7]- [11], which further can be represented in the form of a transfer function [12]. The ladder circuits in [8]- [11] are based on the multicage rotor structure, and they are parametrized by means of numerical optimization. The ladder circuit structure presented in [7] can be be plugged into standard space-vector models, with no need to modify the parameters of the underlying model.…”

Optimisation of the FE Model Based on the No-Load Test Measurement for Estimating Electromagnetic Parameters of an Induction Motor Equivalent Circuit Including the Rotor Deep-Bar Effect

“…Relying on such a model, the airgap-flux-oriented control [20,22] and pseudorotor-flux-oriented control [23] schemes were developed. In the work [24] the presented theoretical basis led to the formulation of the rotor flux space-vector estimator based on the IM space-vector model with the rotor two-terminal network representation. This allows the implementation of the rotor-flux-oriented control scheme with the use of such a model.…”