scholarly journals Reduced-Order Model of Rotor Cage in Multiphase Induction Machines: Application on the Prediction of Torque Pulsations

2020 ◽  
Vol 25 (1) ◽  
pp. 11 ◽  
Author(s):  
Abdelhak Mekahlia ◽  
Eric Semail ◽  
Franck Scuiller ◽  
Hussein Zahr
Keyword(s):  
Induction Machine ◽  
Induction Machines ◽  
Reduced Order Model ◽  
Order Model ◽  
Two Phase ◽  
Reduced Order ◽  
Three Phase ◽  
Torque Pulsations ◽  
Sinusoidal Current ◽  
Rotor Cage

For three-phase induction machines supplied by sinusoidal current, it is usual to model the n-bar squirrel-cage by an equivalent two-phase circuit. For a multiphase induction machine which can be supplied with different harmonics of current, the reduced-order model of the rotor must be more carefully chosen in order to predict the pulsations of torque. The proposed analysis allows to avoid a wrong design with non-sinusoidal magnetomotive forces. An analytical approach is proposed and confirmed by Finite-Element modelling at first for a three-phase induction machine and secondly for a five-phase induction machine.

Advanced Natural Circulation Reduced Order Model With Inclined Channel for Low Pressure Conditions

2018 ◽  
Author(s):  
René Manthey ◽  
Alexander Knospe ◽  
Carsten Lange ◽  
Christoph Schuster ◽  
Antonio Hurtado
Keyword(s):  
Reference Model ◽  
Nonlinear Dynamical Systems ◽  
Natural Circulation ◽  
Dynamical Behavior ◽  
Low Pressure ◽  
Reduced Order Model ◽  
Circulation System ◽  
Order Model ◽  
Two Phase ◽  
Reduced Order

Natural circulation with two-phase flow is a nonlinear dynamical systems, which can show a very complex and strange behavior under specific conditions. The application of stability analysis requires a large computational effort and is cumbersome in case of prediction the dynamical behavior by system codes alone. Therefore, model order reduction techniques are used to compensate this disadvantage by coupling with a bifurcation code such as MatCont. A reduced order model is derived by employing the POD-method to analyze the stability landscape of a low pressure natural circulation system representing passive safety systems such as the containment cooling condenser. The required full order model contains a classical natural circulation loop with a heated section and a riser. The two-phase region is modeled by a drift-flux mixture model. The reliability of the FOM is investigated by comparison with a reference model by the validated system code ATHLET.

Advanced Natural Circulation Reduced-Order Model With Inclined Channel for Low Pressure Conditions

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
René Manthey ◽  
Alexander Knospe ◽  
Carsten Lange ◽  
Christoph Schuster ◽  
Antonio Hurtado
Keyword(s):  
Reference Model ◽  
Nonlinear Dynamical Systems ◽  
Natural Circulation ◽  
Dynamical Behavior ◽  
Low Pressure ◽  
Reduced Order Model ◽  
Circulation System ◽  
Order Model ◽  
Two Phase ◽  
Reduced Order

Abstract Natural circulation with two-phase flow is a nonlinear dynamical systems, which can show a very complex and strange behavior under specific conditions. The application of stability analysis requires a large computational effort and is cumbersome in case of prediction the dynamical behavior by system codes alone. Therefore, model-order reduction techniques are used to compensate this disadvantage by coupling with a bifurcation code such as MatCont. A reduced-order model is derived by employing the proper orthogonal decomposition (POD) to analyze the stability landscape of a low pressure natural circulation system representing passive safety systems such as the containment cooling condenser. The required full-order model contains a classical natural circulation loop with a heated section and a riser. The two-phase region is modeled by a drift–flux mixture model. The reliability of the full-order model is investigated by comparison with a reference model by the validated system code ATHLET.

Nodalized Reduced Ordered Model for Stability Analysis of Supercritical Fluid in Heated Channel

2018 ◽  
Author(s):  
Munendra Pal Singh ◽  
Md. Emadur Rahman ◽  
Suneet Singh
Keyword(s):  
Stability Analysis ◽  
Stability Boundary ◽  
External Pressure ◽  
Reduced Order Model ◽  
Nonlinear Stability Analysis ◽  
Weighted Residual Method ◽  
Order Model ◽  
Two Phase ◽  
Reduced Order ◽  
Heated Channel

In this paper, a novel nodalized reduced order model (NROM) has been developed to analyze the linear stability in a heated channel using supercritical water (SCW) as a coolant. The presented reduced order model is developed based on the two-phase flow system approach. The model is much simplified, which reduced the requirement of computational efforts and resources. In the heated channel, the SCW’s density shows a dramatic downfall near the pseudo-critical temperature, based on which it has been divided into n number of nodes. The one-dimension partial differentiation conservation equations of energy, mass and momentum are used and have been linearized by a small perturbation applied on its steady-state solution. These PDEs are converted into the corresponding time-dependent, nonlinear ordinary differential equations (ODEs) by using weighted residual method applied under some appropriate assumptions and approximations. These sets of ODEs (n+1 equations) are then solved analytically by using a state space approach to capture the stability boundary (SB) in terms of trans-pseudo-critical phase change number (Ntpc), pseudo-subcooling number (Nspc) by applying a constant external pressure drop (ΔPtpc) condition across the channel. The NROM results are found to be in good agreement with the methodology and have been verified by numerical simulation. To extend this as a nonlinear stability analysis, the different types of the Hopf Bifurcation regime are also reported.

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