Thermal Analysis of a Novel Cylindrical Transverse-Flux Permanent-Magnet Linear Machine

Abstract

This paper presents a novel staggered-teeth cylindrical transverse-flux permanent-magnet linear machine (TFPMLM), which aims to improve the power factor and force density. Due to the compact structure and high performance requirement, thermal problems should be seriously considered. The three-dimensional (3-D) temperature field model is established. The determination of convection heat transfer coefficients is discussed. Equivalent thermal conductivities of stator core and winding are given to simplify the analysis. With the thermal effect of the adhesive coatings among permanent magnets (PMs) and mover yoke taken into account, the temperature field distribution and variation rules of the TFPMLM are obtained using the finite volume method (FVM). The influences of slot filling factor and air flow velocity on the temperature field distribution are analyzed. It is found that the hottest spot of the TFPMLM appears in the middle of the end winding; and there is no risk of demagnetization for PMs.

Computationally Efficient Method of Co-Energy Calculation for Transverse Flux Machine Based on Poisson Equation in 2D

“…To enforce force the occurrence of constant difference between the values of vector potential-A on the left and the right boundary it is necessary to perform the following modification of the vector of absolute terms in the expression:L =L − MD (14) where D is a vertical vector that includes, in the elements corresponding to nods from the left boundary, values of the imposed difference of the vector potential A . Numerical value of this difference was denoted with d.D…”

“…Due to their construction, the problems typical for TFM machines are high values of leakage flux [12] and relatively low values of power coefficient [13]. Moreover, due to compact structure, which is an advantage, such machines are susceptible to overheating, which may result in accelerated degradation of permanent magnets [14]. Development of the method of numerical aided design of the machines concerns most often the mechanical properties of the machine being designed, i.e., the achieved mechanical power, the developed torque and its conservation in transient states.…”

Thermal analysis and experimental verification of a staggered‐teeth transverse‐flux permanent‐magnet linear machine

“…Heat transfer coefficient is one of crucial parameters in thermal analysis, which is usually determined by the empirical correlations in heat transfer theory [17,18]. The heat transfer coefficient is expressed as follows:…”

“…Identical thermal parameters and power losses are employed in both models. The detailed NTM and solution are fully reported in [18]. It will not be introduced specifically in this paper.…”

Three-Dimensional Finite-Element Analysis of the Short-Time and Peak Withstand Current Tests in Substation Connectors

“…The heat transfer due to convection is often based on coefficients obtained empirically since it is a complex phenomenon and depends upon several variables such as surface dimensions and shape, flow regime, fluid temperature and properties like density, specific heat, thermal conductivity or kinematic viscosity, among others [38,39]. Diverse heat transfer correlations for isothermal surfaces of the most common geometries are found in [40,41].…”