Design of a linear permanent magnet motor for active vehicle suspension

Traditionally, automotive suspension designs with passive components have been a compromise between the three conflicting demands of road holding, load carrying, and passenger comfort. Linear electromagnetic motor based active suspension has superior controllability and bandwidth, provides shock load isolation between vehicle chassis and wheel, and therefore has a much great potential. It also has the ability to recover energy that is dissipated in the shock absorber in the passive systems and results in a much more energy efficient suspension system. This paper describes the issues pertinent to the design of a high force density tubular permanent magnet motor for active suspension in terms of performance optimization, use of solid stator core for low-cost production and its impact on thrust force, and the assessment of demagnetization risk.