Aron Szucs, Zlatko Kolondzovski, Jan Westerlund and Juha Vahala
The thermal management of electrical insulations poses a challenge in electrical devices as electrical insulators are also thermal insulators. Diamond is the best solid electrical…
Abstract
Purpose
The thermal management of electrical insulations poses a challenge in electrical devices as electrical insulators are also thermal insulators. Diamond is the best solid electrical insulator and thermal conductor. This can lead to a paradigm change for electrical machine winding and lamination insulation design and thermal management. The paper introduces these techniques and discusses its effect for the design of electrical machines and its potential consequences for electromagnetic analysis, for example, in multi-physics modelling. The diamond winding insulation is patent-pending, but the diamond enriched lamination insulation is published for the benefit of the scientific community.
Design/methodology/approach
The windings of electrical machines are insulated to avoid contact between the coil and other conductive components, for example, the stator core. The principle of using mica tape and resin impregnation has not changed for a century and is well established to produce main insulation on a complex conductor shape and size. These insulations have poor heat-conducting properties. Similarly, the insulation of laminated steel sheets comprising the stator and rotor restrict heat flow. Diamond-based insulation provides a new path. Increased thermal conductivity means reduced temperature rise and the reduced thermal time constants in multi-physics simulations and system analysis.
Findings
The largest benefit of a diamond-based core insulation is in electrical machines in which the losses are conducted axially to the coolant. These are machines with radial ducts and effective cooling in the end regions. The main benefit will be in reducing the number of radial ducts that positively affect the size, production costs and the copper losses of the machine. The increased thermal conductivity of the diamond insulation system will reduce the thermal constants noticeably. These will affect system behavior and the corresponding simulation methods.
Originality/value
Diamond insulation can lead to a paradigm change for electrical machine winding and lamination insulation design and thermal management. It might also lead to new modeling requirements in system analysis.
Details
Keywords
Áron Szucs, Antero Arkkio and Tapani Jokinen
In the finite element analysis of electrical machines the multi‐conductor winding in a stator slot is usually modeled simply by a single conductor with constant current density…
Abstract
In the finite element analysis of electrical machines the multi‐conductor winding in a stator slot is usually modeled simply by a single conductor with constant current density. The size of a finite element problem due to the precise modeling of eddy currents in the multi‐conductor windings can be much larger compared to the single conductor model. The paper investigates a new FEM approach for the consideration of eddy‐currents in multi‐conductor windings surrounded by nonlinear media, a case typical in electrical machinery. The method, called elimination of inner nodes, is evaluated in the paper as a possible solution for multi conductor eddy current problems. The paper presents examples and concludes in what circumstances the method of elimination is efficient.