7,372 research outputs found
Modeling of Mutual Saturation in Induction Machines
Mutual saturation between the main flux and the rotor leakage flux appears in induction machines, especially if the rotor slots are skewed or closed. Conventional saturation models used in connection with dynamic equivalent-circuit models do not take this phenomenon into account. In this paper, explicit functions for modeling the mutual saturation are proposed. The proposed functions are physically reasonable, they are easy to fit, and the number of their parameters is small. The proposed functions can be used in real-time applications and in computer simulations where high accuracy and physical consistency are preferable. The model fits well to the data obtained from finite element analysis or experimental data of a 2.2-kW motor.Peer reviewe
Small-Signal Modeling of Mutual Saturation in Induction Machines
A small-signal model is derived for saturated induction machines. Inductances are allowed to saturate as a function of their own current (or flux), and the mutual saturation effect originating mainly from skewed or closed rotor slots is also included in the model. The model fulfills the reciprocity conditions, and it can be applied to parameter identification and to the analysis and development of flux angle estimation methods. As application examples, the parameters of a 2.2-kW induction machine were identiïŹed using the data obtained from time-stepping finite-element analysis and locked-rotor measurements. The proposed model fits well to the data, and the fitted parameters are physically reasonable.Peer reviewe
Modeling of Saturation Due to Main and Leakage Flux Interaction in Induction Machines
Saturation due to the main flux and rotor leakage flux interaction appears in induction machines, especially if the rotor slots are skewed or closed. Conventional saturation models used in connection with dynamic equivalent-circuit models do not take this phenomenon into account. In this paper, explicit functions for modeling this mutual saturation are proposed. These functions are physically reasonable, they are easy to fit, and the number of their parameters is small. The proposed functions can be used in real-time applications and in computer simulations if high accuracy and physical consistency are preferable. The model fits well to the data obtained from finite element analysis or experimental data of a 2.2-kW motor. The model predicts the stator current with good accuracy both in steady state and in transients.Peer reviewe
An analysis of the benefits of signal injection for low-speed sensorless control of induction motors
We analyze why low-speed sensorless control of the IM is intrinsically
difficult, and what is gained by signal injection. The explanation relies on
the control-theoretic concept of observability applied to a general model of
the saturated IM. We show that the IM is not observable when the stator speed
is zero in the absence of signal injection, but that observability is restored
thanks to signal injection and magnetic saturation. The analysis also reveals
that existing sensorless algorithms based on signal injection may perform
poorly for some IMs under particular operating conditions. The approach is
illustrated by simulations and experimental data
Analytical Optimal Currents for Multiphase PMSMs Under Fault Conditions and Saturation
An original analytical expression is presented in this paper to obtain optimal currents minimizing the copper losses of a multi-phase Permanent Magnet Synchronous Motor (PMSM) under fault conditions. Based on the existing solutions [i]opt1 (without zero sequence of current constraint) and [i]opt2 (with zero sequence constraint), this new expression of currents [i]opt3 is obtained by means of a geometrical representation and can be applied to open-circuit, defect of current regulation, current saturation and machine phase short-circuit fault. Simulation results are presented to validate the proposed approach
A Model for Induction Motors with Non-Uniform Air-Gap
Equations to calculate inductances of induction motors, considering non-uniform air-gap, are proposed. The analyzed air-gap variations are static and dynamic eccentricity and stator slots. The equations for inductance calculation, obtained from the modified winding functions and the energy stored in the air-gap, allow considering the effect of rotor bar skewing. Experimental results that validate the proposed method are presented.Fil: Bossio, Guillermo RubĂ©n. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto. Facultad de IngenierĂa. Grupo de ElectrĂłnica Aplicada; ArgentinaFil: de Angelo, Cristian Hernan. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto. Facultad de IngenierĂa. Grupo de ElectrĂłnica Aplicada; ArgentinaFil: Solsona, Jorge Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones en IngenierĂa ElĂ©ctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de IngenierĂa ElĂ©ctrica y de Computadoras. Instituto de Investigaciones en IngenierĂa ElĂ©ctrica "Alfredo Desages"; ArgentinaFil: Garcia, Guillermo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto. Facultad de IngenierĂa. Grupo de ElectrĂłnica Aplicada; ArgentinaFil: Valla, Maria Ines. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones en ElectrĂłnica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en ElectrĂłnica, Control y Procesamiento de Señales; Argentin
An Improved Sideband Current Harmonic Model of Interior PMSM Drive by Considering Magnetic Saturation and Cross-Coupling Effects
The sideband current harmonics, as parasitic characteristics in permanent-magnet synchronous machine (PMSM) drives with space vector pulsewidth modulation technique, will increase the corresponding electromagnetic loss, torque ripple, vibration, and acoustic noises. Therefore, fast yet accurate evaluation of the resultant sideband current harmonic components is of particular importance during the design stage of the drive system. However, the inevitable magnetic saturation and cross-coupling effects in interior PMSM drives would have a significant impact on the current components, while the existing analytical sideband current harmonic model neglects those effects. This paper introduces a significant improvement on the analytical model by taking into account these effects with corresponding nonlinear factors. Experimental results are carried out to underpin the accuracy improvements of the predictions from the proposed model over the existing analytical one. The proposed model can offer a very detailed and insightful revelation of impacts of the magnetic saturation and cross-coupling effects on the corresponding sideband current harmonics
Energy-based modeling of electric motors
We propose a new approach to model electrical machines based on energy
considerations and construction symmetries of the motor. We detail the approach
on the Permanent-Magnet Synchronous Motor and show that it can be extended to
Synchronous Reluctance Motor and Induction Motor. Thanks to this approach we
recover the usual models without any tedious computation. We also consider
effects due to non-sinusoidal windings or saturation and provide experimental
data
Vectorial formalism for analysis and design of polyphase synchronous machines
A vectorial formalism for analysis and design of polyphase synchronous machines without reluctance and saturation effects is described. We prove the equivalence of such a machine with a set of magnetically independent machines, which are electrically and mechanically coupled. Specific problems of polyphase machines can thus be favorably analyzed with this concept. Rules of conception and constraints on electric supply can be deduced. Moreover the vectorial approach, which generalizes the complex phasor method, can also be used to control n-leg Voltage Source Inverters. This methodology is applied to 3-phase and 6- phase synchronous machines
Direct torque control for dual three-phase induction motor drives
A direct torque control (DTC) strategy for dual three-phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees. The DTC strategy is based on a predictive algorithm and is implemented in a synchronous reference frame aligned with the machine stator flux vector. The advantages of the discussed control strategy are constant inverter switching frequency, good transient and steady-state performance, and low distortion of machine currents with respect to direct self-control (DSC) and other DTC schemes with variable switching frequency. Experimental results are presented for a 10-kW DTC dual three-phase induction motor drive prototype
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