Electromagnetic design of bilateral switched reluctance linear motor

The linear motor can reduce the space requirement for their installation because there is no extra mechanical component for transforming rotary motion into product linear motion, such as couplers and ball screws. It makes linear motor as an alternative choice for direct-drive applications [1]-[8]. The switched reluctance motor has received considerable attention for industrial applications due to its low cost, simple structures, ruggedness, and reliability in harsh environments [9]-[11]. The structure parameters are very important to the thrust, power and efficiency of switched reluctance linear motor. The optimized dimensions which can generate maximum output electromagnetic force of motor were got according to the changing trend between geometrical parameters and electromagnetic force. Since the air length of the switched reluctance linear motor is larger than that of the switched reluctance rotary motor, the output capability per unit volume of the switched reluctance linear motor is smaller than that of the switched reluctance rotary motor. The bilateral type linear motor structure is used in this structure because it has two obvious advantages compared with unilateral structure. The structure is equivalent to the unilateral structure added an extra stator excitation. On the other hand, only one side of the mover is fixed with stator excitation in the unilateral structure, making a large electromagnetic suction in normal direction between the mover and the stator which is not expected to exist in most occasions. The electromagnetic suction can offset each other in the bilateral structure.