Analytical Calculation to Optimize Magnetic Planetary Gear Topology to Avoid Auto Slip during Various Torque Requirements for Passenger Car Application

The automotive industry has recently started implementing magnetic gears, in different types, as an alternative design for transmission systems. One such design being the Magnetic planetary gear permanent magnet (MPG-PM) machine. The current methodology and the relevant formulae help to design the magnetic planetary gear system, which does not have design considerations for permanent magnet machines and the influence of magnetic fields. The influence of design characteristics of PM machine, Magnetic field and its material plays a vital role in designing the MPG-PM for electric vehicle applications. A method of optimizing the Gear topology design parameters of a magnetic planetary gear permanent magnet machine (MPG-PM machine) is proposed. The Analytical calculations regarding the design parameters are proposed in relation to power, gear ratios, and other design constraints like packaging parameters i.e., outer diameter, the overall length of the machine. The analytical calculation further is optimized based on the required torque density in the MPG part and power generation in the PM motor part by varying magnetic strength on the inner and outer sides of the ring gear. The analytical method also considers different materials for Ring gear, sun gear and planet gear to vary the magnetic flux through the ring gear to create different degrees of isolations between MPG and PM sections of the machine and to ensure the structural integrity of all the components. The study focuses on evaluating Design parameters with consideration of effect of PM characteristics.