Search

In this paper, a new design of permanent magnet linear synchronous motor (PMLSM) for electromagnetic launcher system (EMLs) has been investigated in terms of the requisite amount of average launching thrust force and thrust force ripple minimization through finite element method. EMLs are a kind of technology used to develop thrust force and launch heavy loads with different applications including military, aerospace, and civil applications. A linear motor as a major part of the system plays a substantial role in this application providing sufficient load launch force. Cogging force and its mitigation techniques are principle challenges in linear motor operation leading to thrust ripples and detrimental effects on positioning precision and dynamic performance of the moving part. In the proposed design, some modifications have been made in the conventional PMLSM structure. Semi-closed slot construction is used for the primary and the pole shoes width has been changed to access minimum thrust ripple value. In order to attain further optimization in PMLSM’s thrust ripple profile, some other modifications have been considered in PM’s shape as arc-shaped magnetic poles. The latter assists to enforce air gap flux density distribution as sinusoidal as possible, and makes further ripple reduction. The results exhibit that the proposed structure has low weight and it is more economical compared to conventional PMLSM with rectangular shape magnet. In addition, the Average thrust force and ripple are improved providing suitable thrust force for throwing the load.

Model-based predictive control (MPC) is one of the most efficient techniques that is widely used in industrial applications. In such controllers, increasing the prediction horizon results in better selection of the optimal control signal sequence. On the other hand, increasing the prediction horizon increase the computational time of the optimization process which make it impossible to be implemented in real time. In order to solve this problem, this paper presents an improved strategy in the field of nonlinear MPC (NMPC) of the permanent magnet synchronous motor (PMSM). The proposed method applies a sequence of reduction weighting coefficients in the cost function, over the prediction horizon. By using the proposed strategy, NMPC give a more accurate response with less number of prediction horizon. This means the computational time is reduced. It also suggests using an incremental algorithm to reduce the computational time. Performance of the proposed Nonlinear MPC (NMPC) scheme is compared with the previous NMPC methods via simulations performed by MATLAB/Simulink software, in permanent magnet synchronous motor drive system. The results show that the use of proposed structure not only lowers prediction horizon and hence computational time, but also it improves speed tracking performance and reduces electromagnetic torque ripple. In addition, using the incremental algorithm also reduces the computational time which makes it suitable for real-time applications.

A new axial magnetic gear (AMG) with enhanced torque density and reduced cogging torque is proposed in this paper. In the new structure, the direction and width of permanent magnets in high-speed rotor are changed and permanent magnets are removed from the modulator while the low-speed rotor remains unchanged. The torque density of the proposed magnetic gear is enhanced by using an appropriate direction and pole pitch for permanent magnets of high-speed rotor. The proposed AMG is compared with recent structures in the literature with the highest torque density. Three-dimensional (3D) finite element analyses are employed to obtain the cogging torque and torque density. The results of the analysis indicate that not only torque density increases but also cogging torque decreases dramatically.

In this paper, a novel two output nine switch-inverter is proposed in order to increase the synchronization speed of induction motors used in electric vehicles (EVs) while improving the efficiency and controllability of the system. The number of switches in the proposed inverter is reduced by 25% compared to double six-switch inverters which conventionally used in EVs. The main characteristics of the considered inverter can be noted as follows: sinusoidal input and outputs, unity output power factor, and specifically, low construction cost due to active switch number reduction. The classical direct torque control method causes torque ripple and speed fluctuations. Therefore, in order to increase accuracy and dynamics of drive system, the SVM-DTC method is proposed, leading to less torque ripple and constant switching frequency. The obtained torque ripple is 2% which is less than the existing structures In order to illustrate advantages of the proposed approach, performance of the EVs in the standard cycles is evaluated.

This paper presents analysis and comparative study of a novel high-torque three-phase switched reluctance motor (SRM) with magnetically isolated stator segments. In the proposed SRM, each segment has a concentric winding located on the center body of it and two diametrically opposite windings which form the motor phase. There are four salient poles in the stator segment. Two of them share their flux path in the center body of the segment. The rotor has a solid structure including twenty two salient poles. In this unique SRM, stator segments topology, number of the stator segments poles and the rotor poles, and angular distance of the stator segments are selected so that the motor properly operates in both directions. Two-phase design with different pole combination is also possible. During operation, there are short flux paths along two adjacent rotor poles and excited segment poles. Therefore, the proposed SRM has all benefits of the short flux path structures. The principle and fundamentals of the proposed SRM design are detailed in the paper. The motor is analysed using finite element method (FEM) and some comparisons are reasonably carried out with other SRM configurations. Finally, a prototype motor is built and experimental results validate the performance predictions in the proposed motor.

This paper considers a new switched reluctance motor (SRM) structure aiming at high starting torque with low volume. For some applications such as EVs (Electrical Vehicles), the motor volume and starting torque is a critical point in its design. In many methods, reducing the motor volume causes reduction in starting torque and decreases the motor efficiency. Unlike conventional SRMs, the rotor pole is skewed in the proposed structure along the motor axis. An approximated two-dimensional finite element method (FEM) is used to speed up computational time and some comparisons with three-dimensional FEM are considered for more reliability. Final results show the efficiency of the proposed structure.

This paper presents a new design to reduce torque ripple in Switched Reluctance Motors (SRM). Although SRM possesses many advantages in terms of motor structure, it suffers from large torque ripple that causes problems such as vibration and acoustic noise. The paper describes new rotor and stator pole shapes with a non-uniform air gap profile to reduce torque ripple while retaining its average value. An optimization using fuzzy strategy is successfully performed after sensitivity analysis. The two dimensional (2-D) finite element method (FEM) results, have demonstrated validity of the proposed new design.

A switched Reluctance motor (SRM) has several desirable features, including simple construction, high reliability and low cost. However, it suffers from large torque ripple, highly non-uniform torque output and magnetization characteristics and large noise. Several studies have succeeded in torque ripple reduction for SRM using Direct Torque Control (DTC) technique. DTC method has many advantages over conventional voltage control and current chopping mode control such as simple algorithm, less torque ripple and instantaneous response to the torque command. In this paper, DTC method is proposed for a 5-phase 10/8 SRM. The performance of the motor is demonstrated through the computer simulation in Mtalab/Simulink. Then, the obtained results are verified by comparison with the corresponding results of a 3-phase 6/4 motor performance.