Variable reluctance (VR) resolvers are widely used in industrial applications such as aerospace, military, robotic, control of hybrid motors, and navigation for solar systems. Variable reluctance resolvers are preferred because of simplified structure and affordable prices in many applications in comparison with to the coiled rotor resolvers. In this study, effect of variation of physical parameters including skewing and opening slots of stator is investigated. The performance of the proposed structure is simulated by using a 3-D time stepping finite element method. تفاصيل المقالة

In this paper, a method to compute optimum impedance of fault current limiter (FCL) is presented. The type of FCL impedance based on its resistance, inductance and capacitance has an effect on the amount of short circuit current reduction. Therefore, for an optimum result a complex parameter is selected for the FCL impedance. In addition, magnitude of short circuit current is also affected by location of FCL and the amount of system parameter. Due to the cost difference of real and imaginary components of FCL impedance, this calculation is based of sensitivity analysis, such that while minimizing the cost of impedance parts for FCL, reduction in fault current is maximized. Moreover, based on the maximum allowable current constraint and using a developed computer program, an optimum FCL impedance for a wide range of prices for real and imaginary components are computed. These analyses were applied on a 11 bus test system with using a specified single location of FCL. تفاصيل المقالة

Increase of energy consumption and air pollution are big crises in recent two decades. Due to these crises and also increase of energy costs, utilization of hybrid electric vehicles becomes conventional and vehicle companies are increasing their investment in these kinds of vehicles. The main issue for these vehicles, besides energy storage system, is efficiency of electric motor and its weight and cost. Axial Flux Permanent Magnet Synchronous Motors (AFPMSM) have become popular for hybrid vehicles as they have better efficiency and less weight. In this paper an AFPMSM, which would be used in hybrid electric vehicles, is designed to get less weight and cost and more efficiency. PSO and GA algorithms have been applied in this design. Inner and outer diameter of axial flux permanent magnet motor and air gap flux density are taken as variables in the mentioned design. تفاصيل المقالة

Torque ripple in electrical machines is an important issue which may cause several problems in use. In permanent magnet machines and machines with DC excitation, main part of torque ripple is because of cogging torque. There are several ways to reduce this torque and in permanent magnet machines, optimized shape of permanent magnets is one of them. In this paper, a novel shape of permanent magnet in an Axial Flux Permanent Magnet Synchronous Machine (AFPMSM) is proposed which reduces the motor cogging torque and hence over come the torque ripple. First, reference motor is designed with conventional PM shape and then novel PM shaped AFPMSM is designed. These two machines are analyzed by MAXWELL software and then their torque ripples are computed. Results show 35 percent reduction of cogging torque. تفاصيل المقالة

In this paper optimal allocation of electric vehicles parking and distributed generations (DGs) with objective of minimizing energy costs is proposed by using a hybrid water cycle-moth flame optimizer (WCMFO) algorithm. The purpose of the study is reduction the losses of distribution system, improvement the voltage profile, minimization the distribution system voltage deviations, and reduction the energy received from the main feeder. The optimization problem is implemented on a 33 IEEE bus distribution system. In this study, due to the optimal combination of WCA and MFO methods, WCMFO method is used to solve the problem with high convergence rate. In this study, the proposed method is compared with WCA, MFO and particle swarm optimization (PSO) methods. The simulation results show superiority of the proposed hybrid method in achieving lower cost and high convergence rate. The results show that with the optimal use of electrical parking and also DGs, the system capacity can be released and the level of upstream system dependency can be reduced. It also reduced the amount of system energy not supplied. تفاصيل المقالة