Design Methodology for a PM Electrical Variable Transmission Used in HEV

Designing a permanent magnet electrical variable transmission is a cumbersome task, regardless of the considered application. The main reason for this is the iterative design process using a computationally intensive finite element model calculations that is necessary to model its behaviour. This makes it difficult to study or visualize the impact of design changes on, for example, the fuel consumption or cost of a hybrid electrical vehicle. To solve this, electromagnetic scaling laws are used to set up a performance map of the entire system. This map is able to present the performance (i.e. fuel consumption, cost, maximum acceleration, etc.) as a function of an axial and radial scaling factor. The map thus displays the performance of a series of designs which enable the reader to select the optimal one in a graphical way. Furthermore, feasibility constraints such as maximum weight, are added. These constraints allow to reject designs but make it also possible to study the performance as a function of weight or material cost. This is particularly useful for manufacturers as it gives an idea of how their investment is translated into a reduction in fuel consumption.