Abstract : A novel design method for internal magnetic pole structure motors is proposed from the perspective of saliency ratio. To ensure comparability of motor characteristics, it is assumed that all motors operate at the same base point and employ the same control strategy. The influence of saliency ratio (l[sub]d[/sub]/l[sub]q[/sub]) on the maximum possible speed of the motor, inverter power (vA), and current control characteristics is investigated in detail. The conclusions obtained provide positive reference guidance for the selection and design of motors and their drive systems. Keywords : internal magnetic poles; permanent magnet synchronous linear motor; saliency ratio; field weakening. Permanent magnet synchronous linear motors can broaden their speed regulation range using field weakening technology. Permanent magnet motors are classified into two types based on the installation position of the permanent magnet: surface pole motors and internal pole motors. The saliency ratio of surface poles is ld/lq = 1, while the saliency ratio of internal poles is ld/lq < 1. 1. Stable Operation State of Permanent Magnet Synchronous Linear Motors To simplify the analysis, the following assumptions are made for permanent magnet synchronous linear motors: a. Armature resistance is ignored; b. The permeability of the ferromagnetic material tends to infinity, and the saturation effect of the magnetic field is not considered; c. Iron losses are ignored; d. The demagnetizing effect of the armature current on the permanent magnet is not considered, and the permanent magnet has appropriate coercivity; e. Friction is ignored. For ease of comparison, all data are expressed in per-unit form. The base values ​​for the per-unit values ​​are defined as follows: the voltage base value v_b is the maximum inverter voltage; the thrust base value f_b is the motor thrust when the motor voltage equals v_b and the current control angle can generate the maximum thrust per unit; the angular velocity base value w_b is the electrical angular velocity when the thrust equals f_b (assuming the same load per-unit value). The base values ​​for the per-unit values ​​of other quantities are calculated using the following formulas: [b][align=center]For more details, please click: Design of Permanent Magnet Synchronous Linear Motor for Field Weakening Speed ​​Regulation[/align][/b]