ABSTRACT
Plunger solenoids are called electromagnets and are used extensively in standard applications such as electric power switches, and door lockers, enjoying substantial worldwide markets. In applications with constant frequency oscillatory linear motion, operation at resonance is sought to increase efficiency and thus reduce the power electronics kilovoltampere ratings. The chapter deals with the principles of Permanent magnets (PM)-less plunger solenoids, and with their modeling. It considers magnetic saturation and eddy currents; and aims to develop a few design and control studies for configurations without and with PMs. Flat active area solenoids may be made of laminations, though noise and vibration may be excessive, but for tubular topologies, which are notably more favorable, soft magnetic composite (SMC) iron cores are the solution. PM-less plunger solenoids are less expensive and, provided with low-loss SMC cores, they may be used both in on-off motion applications and in position controlled valves.
