Dual-long-secondary and primary permanent magnetic field modulation linear motor for oil pumping unit

The invention discloses a dual-long-secondary and primary permanent magnetic field modulation linear motor for an oil pumping unit. The motor comprises two long secondary stators arranged symmetrically and oppositely, a short primary rotor arranged between the two long secondary stators, and air gaps formed between the short primary rotor and the long secondary stators, wherein the short primary rotor comprises primary iron cores arranged at equal intervals in a motion direction, and primary permanent magnets embedded between the adjacent primary iron cores; the primary iron cores are wider than the primary permanent magnets, so that primary teeth are formed on two sides of each primary iron core in the width direction; and armature windings are nested on the primary teeth. According to the motor, the armature windings and the permanent magnets are all arranged in the short primary rotor; the long secondary stators only adopt salient pole flat plate structures composed of magnetic materials; a primary magnetic field is modulated by air gap permeance changes caused by secondary salient poles to realize electromechanical energy conversion; and the motor has the characteristics of simple structure, high reliability, low cost and high thrust density.