Three-Phase AC Linear Proportional Solenoid Actuator With Zero Hysteresis in Current-Thrust Force Characteristics

An electromagnetic proportional solenoid is used as a force control device to generate thrust force acting on a valve element in a hydraulic pressure control valve. However, a conventional proportional solenoid has the problem of hysteresis appearing in its current-thrust force characteristics, which is induced by friction and magnetic hysteresis. In order to reduce hysteresis, this paper proposes the three-phase ac solenoid that reproduces a pseudo-magnetic bearing. Its prototype reduces hysteresis and achieves the same performance as the conventional proportional solenoid. The magnetic pole shape and the current input condition considering the magnetic flux density saturation are presented based on electromagnetic field analysis.