Modeling of Losses Due to Inter-laminar Short Circuit Currents in Lamination Stacks
In this paper, a surface boundary layer model based on the discontinuity of the tangential component of the magnetic field due to the existence of the surface current is formulated and coupled with a 2D finite element. The additional loss was calculated using the surface boundary layer model in the UI type core and compared with finely discretized geometry. The maximum difference of 19 % was obtained when the surface boundary layer model was compared to the finely discretized model.
Estimation of Additional Losses Due to Random Contacts at the Edges of an Electrical Machine
In this paper, the developed surface boundary model was implemented in the induction machine to study the inter-laminar contacts. The stator and rotor losses increased with the thickness of the contacts. A statistical analysis was also performed, and the mean value of electromagnetic losses increased by 7.7 % due to random galvanic contacts.
Efficient Finite Element Method to Estimate Eddy Current Loss due to Random Interlaminar Contacts in Electrical Sheets
In this paper, a stochastic Galerkin finite element formulation was implemented to consider random inter-laminar contacts in the magnetic vector potential formulation. The random conductivities at the edges of the electrical sheets are approximated using a random conductivity field and are propagated through the finite element formulation. The implementation of the stochastic Galerkin finite element method reduced the computation time compared to Monte-Carlo method by 76 %.
Effciency of an Electrical Machine in Electric Vehicle Application
Machines have always made life simpler, directly or indirectly. They have been developed for a very wide range of applications. For the per- formance analysis of any machine, one important parameter to be considered is the machine loss. This consideration has signifcances like determining the effciency of the machine which in turn infuences the operating cost, determining the heating of machine and for accounting the voltage drops or current component associated with the cause of the losses and many more. Losses in electrical machines can be categorized according to the causes or phenomena that produce them. The effciency of an electrical machine directly depends on different kind of losses in the machine. Therefore, in this paper we primarily focus on the losses in the machine. First, all possible losses, their causes and effects in an electrical machine have been explained. A brief account of calculating those losses has also been explained. The standard method of calculating the effciency follows after that. Finally, a fnite element analysis is performed for a test machine and the losses and the effciency of the test machine is studied.
Efficiency map prediction of flux switching machine
The foremost requirement of todays electric vehicle is comfort and power. The challenge that todays electric motor designer face is to have a large traction torque at low speed and wide constant power speed range. Flux switching machine has magnets parallel to stator winding that avoids the risk of demagnetisation because of better thermal cooling. Efficiency map of such machines can be determined efficiently from the response surface method using control algorithm, optimisation and finite element analysis.
Eddy current loss calculation in burred laminated cores
Cores of electrical machines are usually laminated to reduce eddy current loss. Punching and pressing of the electrical sheets can deteriorate the interlaminar insulation and hence, can cause interlaminar currents to flow across the stack. In this paper, eddy current loss due to interlaminar currents is studied considering the conductivity of the sheets in both across and along the lamination direction. A statistical study of random interlaminar contacts and thermal measurements are also presented in this paper.
Experimental and Theoretical Study of Interlaminar Eddy Current Losses in Laminated Cores
In this paper, eddy current losses of the laminated core, with and without the inter-laminar contacts, were determined experimentally. Based on the results obtained from the measurement, an iterative method was used to determine equivalent conductivites of the laminated core by performing several simulations. The eddy current loss coefficient was increased by 2 % in the case of the inter-laminar fault at one limb and by 2.7 % in the case of the inter-laminar fault at two limbs of the EI core.
Thermographic Measurement and Simulation of Power Losses Due to Interlaminar Contacts in Electrical Sheets
In this paper, a novel measurement setup is designed to perform thermal and short-circuit tests of electrical sheets. A FLIR T640 thermal camera was used to record the initial rise of hotspot temperature. Based on the measurement values inter-laminar contact size was estimated. The electromagnetic and thermal finite element method was formulated to study and validate the analytical model.
Sahas Bikram Shah 