Modeling and Simulation of Flux-Optimized Induction Motor Drive (original) (raw)
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Efficiency and Performance Optimization of Induction Motor Drive
Induction Motor(IM) are known for its power/mass ratio, its efficiency, low cost and maintenance free performance during its life cycle therefore known as workhorses of industries. But huge amount of energy is wasted by IM due to their poor efficiency, also the operating cost is high. Therefore a small increment in efficiency may lead to contribute huge significant effect on the entire energy saving. The main key features in which estimation and reproduction of optimal flux component of current (Ids) depends, are loss model control (LMC) and search control (SC). To drive loss-minimization expression, core saturation is considered with d-q loss model of IM. Ids value expression for various load profiles, this loss expression is used to derive optimal Ids expression and tabulation is done. According to the table, a model is designed. The optimal Ids* value can be calculated, which depends upon run-time profile, followed by feed-forward manner and thus eliminates complex computation of run time loss model. Comparison is done between proposed operation that is optimal Ids and constant Ids obtained by conventional method. Increment of 1-12% efficiency is observed.
Loss-minimizing flux level control of induction motor drives
This paper applies a dynamic space-vector model to loss-minimizing control in induction motor drives. The induction motor model, which takes hysteresis losses and eddy-current losses as well as the magnetic saturation into account, improves the flux estimation and rotor-flux-oriented control. Based on the corresponding steady-state loss function, a method is proposed for solving the loss-minimizing flux reference at each sampling period. A flux controller augmented with a voltage feedback algorithm is applied for improving the dynamic operation and field weakening. Both the steady-state and dynamic performance of the proposed method is investigated using laboratory experiments with a 2.2-kW induction motor drive. The method improves the accuracy of the loss minimization and torque production, it does not require excessive computational resources, and it shows fast convergence to the optimum flux level. he has been working toward the Ph.D. degree at Aalto University, Espoo, Finland.
From the ideal to the real induction machine: Modelling approach and experimental validation
Journal of Magnetism and Magnetic Materials, 2008
The aim of this paper is to discuss the ability of a numerical code in reproducing a real machine behavior, with particular reference to the cage currents of a four-poles 50 Hz induction motor. The used 2D Finite Element method (FEM) is based on voltage driven field formulation, handling the nonlinearity by the fixed point technique and the rotor movement by the sliding mesh approach. The numerical outcomes are validated by experiments performed on a dedicated laboratory setup, able to provide the instantaneous cage currents. Then, a spectral algorithm has been applied to the experimental and computed variables and the results have been interpreted in terms of magneto-motive forces. This approach allows us to determine possible machine eccentricities or other asymmetries not introduced in the simulations. Discussing the computed and measured spectra and excluding in the last ones the lines corresponding to non-idealities, an evaluation on how the modelling approach reproduces accurately the real machine is possible. The validated model will be able to reproduce the machine behavior of usual induction machines whose rotor currents are not measurable. r
Challenges of the Optimization of a High-Speed Induction Machine for Naval Applications
Energies
In several industrial sectors, induction machines are being replaced with permanent magnet based alternatives, owing to the potential for higher power density and efficiency. However, high-speed applications feature a wide flux-weakening region, where advanced induction machines could bring benefits in terms of system-level optimization. This paper gives an overview the technological challenges for high-speed drives with induction machines, materials, simulations and future challenges for the power electronics in these applications. The target application is a high-speed induction machine for a naval turbocharging system. The comparison with permanent magnet synchronous machines will demonstrate how the extended flux weakening operation effectively allows for a weight reduction of the overall system.
Indirect field oriented control (IFOC) and direct torque control (DTC) have been widely commercialized in induction motor drives, with each being favored by its supporters. In this paper, the dynamic performance of these drives for an electric vehicle application is examined, and sensitivities to parameter variations affecting this dynamic performance are explored. Key performance measures include torque and speed transients. To achieve decoupling between the drive and the switching scheme, both drives are simulated in MATLAB/Simulink for different switching schemes. These schemes include space-vector pulse-width modulation (SVPWM), and hysteretic control for IFOC and DTC. DTC is also simulated with a switching table. Experimental results for some of these schemes are also presented. Results show that control performance is influenced by the switching scheme. It is shown that when IFOC and DTC are used with SVPWM, the torque response of IFOC is superior. These characteristics are verified by simulations. The work opens further discussion for the feasibility of applying IFOC in electric and hybrid-electric vehicles. 1 Nomenclature P: Number of poles r s : Stator resistance (Ω) r r : Rotor resistance (Ω) L m : Mutual inductance (H) L s : Stator inductance (H) L r : Rotor inductance (H) τ r = L r /r r (s) σ = (L s L r-L m 2)/L r : Leakage factor (H) ς = (L s L r-L m 2)/L m 2 : per-unit leakage factor i qs : Quadrature stator current (A) i ds : Direct stator current (A) i abcs : 3-phase stator current (A) v qs : Quadrature stator voltage (V) v ds : Direct stator voltage (V) v abcs : 3-phase stator voltage (V) T e : Electromechanical torque (N·m) T L : Load torque (N·m) θ e : Electrical angle (rad) ω e : Electrical frequency (rad/s) ω r : Rotor speed (rad/s) ω rm : Mechanical speed (rad/s) ω sl : Slip frequency (rad/s) 1 This work was supported in part by the U.S. Office of Naval Research under Award Number N00014-08-1-0397. λ qs : Quadrature stator flux linkage (V·s) λ ds : Direct stator flux linkage (V·s) λ qr : Quadrature rotor flux linkage (V·s) λ dr : Direct rotor flux linkage (V·s) λ s = : Stator flux magnitude (V·s) λ r = : Rotor flux magnitude (V·s) The superscript "*" denotes a command input. The superscripts "e" and "s" denote variables in the synchronous and stationary reference frames, respectively.
Journal of Engineering Science and Technology
The development of electromagnetic devices as machines, transformers, heating devices confronts the engineers with several problems. For the design of an optimized geometry and the prediction of the operational behaviour an accurate knowledge of the dependencies of the field quantities inside the magnetic circuits is necessary. This paper provides the eddy current and core flux density distribution analysis in linear induction motor. Magnetic flux in the air gap of the Linear Induction Motor (LIM) is reduced to various losses such as end effects, fringes, effect, skin effects etc. The finite element based software package COMSOL Multiphysics Inc. USA is used to get the reliable and accurate computational results for optimization the performance of Linear Induction Motor (LIM). The geometrical characteristics of LIM are varied to find the optimal point of thrust and minimum flux leakage during static and dynamic conditions.
Induction machine speed control with flux optimization
Control Engineering Practice, 2010
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