This paper presents a predictive strategy to control torque and FLUX of an AXIAL FLUX permanent magnet (AFPM) machine. Unlike conventional direct torque control (DTC) for permanent magnet MACHINES that only six actives voltage vectors of the inverter are used to control the torque and FLUX of the machine, in predictive torque control (PTC), zero voltage vectors are used to control too. Thus, the number of voltage vectors to control AFPM increases and leads to faster dynamic torque response and lower ripples of torque and FLUX. In predictive torque control presented in this paper, responses of torque and FLUX are computed for all possible switching states of the inverter at every sample time according to the discrete time model of the machine and then the switching state that optimizes ripples of torque and FLUX will be applied in the next discrete-time interval. Simulation results, which confirm the good performance of the proposed predictive torque control are presented.

This paper present an improved design of AXIAL FLUX Permanent Magnet (AFPM) synchronous MACHINES using PSO algorithm that consider practical limits. At first sizing equations is provided and 20 kW AFPM machine is designed, and then output power density is improved using PSO algorithm. A comparison between improved designed AFPM machine and a prototype constructed machine is performed. Improved machine has more output power density than constructed machine. Then magnetic FLUX density is calculated based on Maxwell equations analytically. Analytical results have good agreement with finite element method (FEM) results. Use of analytical method takes much less computational time than FEM dose.

In this paper, a modified analytic approach to the calculation of magnetic field in a slot-less, two-rotor AXIAL-FLUX permanent magnet machine is presented. The analytic-modeling is based on calculation of scalar and vector magnetic potentials which are produced by the armature windings and the magnets. The magnet and the armature windings are modeled by a magnetization vector and a two-dimensional current sheet, respectively. The effects of the armature reaction and the harmonics of field are also considered. The simulation of magnetic field by the analytic model is compared with that of a two-dimensional finite element analysis. The proposed analytic model predicts the magnetic field within 5% compared to the finite element method. Ultimately, by using the analytic model in a genetic algorithm method, which is a known method in optimization, an optimum design of an AXIAL-FLUX permanent magnet machine is presented.

Mechanical errors are one of the most common errors related to electric MACHINES. Among them, eccentricities have the major share of mechanical errors. Resolvers, as an electric machine, can be affected by eccentricities or the electric motor connected to it. The existence of eccentricities in the resolvers, which can be caused by the rotation of the machine at critical speed, incorrect installation of the rotor and stator, core turning defects, and wear and corrosion of the bearings, leads to an increase in the position estimation error. The position estimation error will eventually increase the torque fluctuations, reduce the efficiency, lose the ideal control of the electric motor, and disrupt the automation process. Therefore, providing indicators to detect the occurrence of eccentricity in the resolver can be a preventive solution. Based on this, in this article, focusing on the inclined eccentricity, the equations describing air gap reluctance, magnetic FLUX density, and mutual inductance will be presented using the modified winding function method. By using the relationships describing the output voltage, the harmonic spectrum of the output voltage in the static and dynamic eccentricities will be compared with the healthy mode, and an index will be provided to identify static and dynamic mechanical error.

This study aimed to provide the analytical design, optimization, and three-dimensional (3D) simulation through finite element method of a coreless stator AXIAL field FLUX-switching motor (AFFSM). The motor consists of two indented rotors with a coreless stator between them consisting of a magnet and winding. First of the motor electrical and magnetic design was performed and its basic parameters were calculated. Then, the optimization of the machine was evaluated implementing the Taguchi algorithm in order to minimize the motor cogging torque. Some of the basic motor dimensions, such as the magnet length and width, the rotor tooth width and height, and the back iron thickness, were selected as optimization variables, and the best combination of these variables was obtained by changing them in a certain range to achieve the desired objective. Then, the accuracy of analytical design and optimization was evaluated through forming a 3D finite element method (FEM) of the motor and investigating its performance. Comparison of the optimized and primary motor revealed that the optimal design had a better performance than the initial. Finally, a prototype of the proposed motor was fabricated and tested, which indicated that the experimental results were largely similar to the analytical results.

Coreless AXIAL FLUX permanent magnet (PM) MACHINES (AFPM) have attracted significant interest over the last decades as an ideal candidate for a wide range of applications. This is generally due to their advantages, such as the high torque density, high power density, and the light weight. This paper investigates the performance of a coreless AXIAL FLUX-switching generator (AFSMG) with improved torque characteristics. The inherent feature of the AXIAL FLUX-switching MACHINES is the high cogging torque. Hence the main advantage and the novelty of this research is addressing a suitable key for its torque characteristics challenges. In this regard, a comprehensive study is done on rotor tooth shape. First, the geometry and the shape of the rotor tooth are optimized, and then the skewing technique is applied to minimize the cogging torque and improve the total harmonic distortion. Finally, the cogging torque and the THD are calculated in the primary design and the optimal design. The Taguchi method is utilized to improve the primary model. A comparative analysis of the primary and optimized model is carried out, which indicates the better performance of the optimized design. Furthermore, the 3D finite element method is applied to verify the results of the presented model.

Design methodology of a compact size charging system for emergency uses is investigated in this paper. The system consists of a gearing unit, a generator, a charger, and some battery cells. The system’ s electrical model has been introduced and a 3-phase AXIAL FLUX surface mounted PM generator with a concentrated winding is picked as a generation unit. The basic equations needed for the generator design are presented as well as the general considerations and constraints for the designs. After validating the design equations using Finite Element Analysis, sizing equations are used to design different MACHINES. The resulted designs are compared based on main characteristics including output power, power delivered to the battery, and generator efficiency. Finally, the performance of the valid designs in the system model is analyzed over a wide speed range. The proposed methodology could be used to design portable power generation units for such applications as rescuing, power system outage, camping, and so on.

Compactness and lightness make high-speed AXIAL-FLUX MACHINES eligible for distributed generation application with microturbine. In a high-speed generator driven by micro-turbines, the rotor speed is normally above 30, 000 rpm and may even exceed 100, 000 rpm. The frequency for FLUX variation is more than 1 kHz. Therefore, designing such a highspeed generator is quite different, in mechanical and electromagnetic respects, from designing conventional generators with low speed and low frequency. Important considerations in designing high-speed AXIAL-FLUX generators (HSAFG) for microturbine are discussed in this paper. Results of the efficiency sensitivity versus air gap of the machine are also presented.