Design and Optimization Method for a High Power Eddy Current Brake with a Magneto Isotropic Material Structure for the Use in Electrified Heavy Duty Trucks

Abstract

In this work, an eddy current brake (ECB) with a magneto isotropic material structure that eliminates the skin effect is shown, which is optimized in this work for an electrified heavy duty truck. Due to the isotropic structure the eddy currents and the heat are distributed almost homogeneously in the material. The material structure consists of steel pins which transfer the magnetic flux from the poles through perforated aluminium sheets. Coolant flows between the aluminium sheets and the number and thickness of the sheets can be selected almost freely, thereby dramatically increasing the surface area in contact with the cooling liquid. The work focuses primarily on the design and optimization method based on a electromagnetic model of the eddy current brake and thermal models for the excitation windings. The electromagnetic model for calculating the torque as a result of the eddy currents is validated with an error of less than 10%. Further, the results of the optimization method show that in emergency braking more than 80% of the braking energy can be converted with the eddy current brake shown here at a power density of approx. 10 kW / kg.