Production cost modeling for permanent magnet synchronous machines for electric vehicles

Abstract

A cost model for the estimation of production costs of permanent magnet synchronous machines (PMSM) is presented, which allows to alter design choices such as wire technology, winding layout, cooling system, materials and more. With the goal to make results reproducible by others, the methods are explained in detail and used data and assumptions are given. The developed model helps to understand the interaction between the design of PMSM, manufacturing methods and the resulting costs. With it, different PMSM technologies and materials can be evaluated regarding its influence on the production costs, which is a perquisite to find the best compromise between performance and costs. Production volume is shown to be the most decisive factor for the resulting production costs. Between minimum and maximum assumed volumes, an average cost per unit reduction of 67% could be observed. Furthermore, the results imply that the winding production is responsible for the greatest part of the overall costs, followed by the rotor assembly (including rare earth magnets). When using the model to compare different wire types, it can be stated that up to a production volume of roughly 150,000 units/year, hairpin wires are more expensive to produce. Above this volume, hairpin windings will get cheaper than round wire windings due to its higher grade of automation of the production process. Through the conducted investigations and the presented results, it is demonstrated that the cost model can serve to evaluate technologies with regards to costs in the early development stage. This way a more holistic assessment of technologies for PMSM is possible, helping to find the ideal compromises between costs and performance and to increase the attractiveness of sustainable mobility.

Remanufacturing a Synchronous Reluctance Machine with Aluminum Winding: An Open Benchmark Problem for FEM Analysis

“…From an economic point of view, rewinding the electric machine with a 1.6 mm diameter aluminium winding had an overall cost of EUR 342.66, including disassembly, rewinding, insulation, control measurements, and assembly in this particular case. The breakdown of the costs, which is presented in Table 8, was achieved by assuming the contribution of different cost categories to the overall costs for different production volumes as defined by Hemsen et al [87]. The study of [87] presented a cost estimation model that can be used to determine the production costs of electric machines, thereby providing the flexibility to modify various design choices such as wire technology, winding layout, cooling system, materials, and other such factors that can impact the production costs.…”

“…The breakdown of the costs, which is presented in Table 8, was achieved by assuming the contribution of different cost categories to the overall costs for different production volumes as defined by Hemsen et al [87]. The study of [87] presented a cost estimation model that can be used to determine the production costs of electric machines, thereby providing the flexibility to modify various design choices such as wire technology, winding layout, cooling system, materials, and other such factors that can impact the production costs. This paper used the model presented in [87] to approximate the remanufacturing costs, which are presented in Table 8.…”

“…The study of [87] presented a cost estimation model that can be used to determine the production costs of electric machines, thereby providing the flexibility to modify various design choices such as wire technology, winding layout, cooling system, materials, and other such factors that can impact the production costs. This paper used the model presented in [87] to approximate the remanufacturing costs, which are presented in Table 8. As only one unique electric machine was remanufactured, small-volume production was considered.…”