Calculation of Performance Indicators in Hybrid Excitation Synchronous Machine as Well as Torque Ripple Minimization

Smooth and distortion-free torque is one of the most important characteristics of instantaneous torque in the hybrid vehicle. In this paper, the instantaneous torque is firstly calculated by solving Maxwell's equations which are partial differential equations. The general solution is determined by a separate variable method. They include two variables in radial and tangential directions. Consequently, they require two types of boundary and interface conditions in mentioned directions for assigning integral constants. Then, the impact of the pole arc to pole pitch ratio, slot-opening size, air gap radius and the integral and fractional slot structures are separately examined to reduce torque ripple. Additionally, magnetization pattern plays an important role in the magnetic field and instantaneous torque. Three magnetization patterns including radial, parallel and 9-segment magnetization patterns are introduced and assessed. Next, considering the effect of the aforementioned factors, an optimal structure that has the least distortion will be proposed so that the torque fluctuations are in acceptable range. After that, cogging, reluctance, electromagnetic and instantaneous torque are calculated. It is also important to remember that, Back-EMF (based on flux path in teeth for two types winding consist of alternate-teeth and all-teeth non-overlapping winding) and Torque-Speed characteristics are computed for the presented hybrid vehicle. Finally, the impact of the temperature on the all torque component, induced voltage magnitude as well as Torque-speed chart of hybrid vehicles based on the response of Maxwell's equations are determined. The model computations have been performed with Matlab software.