Analysis on dynamic characteristics of hybrid stepping motor and control of its power converter

An advanced lumped parameter model (LPM) taking into account magnetic saturation is developed for the analysis of a five-phase hybrid stepping motor. The permeance of the air gap is calculated as a function of the applied magnetomotive force (MMF) and the rotor position using two-dimensional Finite Element Method (2D FEM). The LPM with 2D FEM assistance provides a fast solution for the torque characteristics in the form of a continuous function. The calculated static torque is shown accurate compared with the experimental results even in the operation range where severe saturation occurs.; For the success of the LPM the accurate permeance values at each magnetic operating condition are required, which can be obtained by 2D FEM. An accurate and reliable 2D FEM model for calculation of the permeance, therefore, plays a crucial role in the LPM. An FEM model requires not only the geometry of the teeth of the stator and rotor but also their material properties which are represented by the nonlinear magnetization curves. The FEM-computed permeance turns out very sensitive to the slope of the magnetization curve. Care must be taken in modeling the air gap region in the 2D FEM because energy conversion between the magnetic energy and the mechanical energy occurs in the air gap. The fact that the air gap length is only 50micron, not sufficient for well-shaped square elements, and the meshes of the stator side and the rotor side must match at every rotor position makes the modeling difficult. This explains why a complete 3D FEM model of a hybrid stepping motor is rare in literature. Despite its modeling difficulty 3D FEM can be used for general configurations without the limitations of the LPM, which is an advantage over the LPM. The LPM results and the 3D FEM results are both compared with the experimental results, and the pros and cons are discussed.; A five-phase can be operated under several modes including full-step, half step, and micro-step modes. Regardless of the operating mode the response of the five-phase HSM is the step response because the excitation inputs are a series of pulse trains. This is why the step response analysis has been one of the most important topics in the field of five-please HSM. In order to address this topic effectively, a linear dynamic model is established. The original dynamic model, having highly nonlinear terms, is simplified to identify the fundamentals of the dynamic characteristics of the five-phase HSM such as the resonance frequencies and damping effects. (Abstract shortened by UMI.)...