Performance Of Synchronous Reluctance Motor Research Articles

Impact of Manufacturing Stresses On Multiple-Rib Synchronous Reluctance Motor Performance

The effects of manufacturing stresses on the overall magnetic properties of electrical steel core applied in the stator and transversally-laminated rotor of Synchronous Reluctance motors are studied. In addition, it is investigated how the -manufacturing-degraded electrical steel core affects the electromagnetic performance of two different Synchronous Reluctance motors. The traditional transversally-laminated rotor of this kind of a machine requires the adoption of mechanical elements (inner and tangential ribs) to maintain its mechanical integrity. Especially, for high-speed applications, the number of rotor ribs must be increased to make the rotor withstand higher centrifugal forces. Lamination manufacturing typically affects the magnetic properties of electrical steel by reducing its permeability at the machined edge. This machining effect is greater when the overall core layer area surrounded by the machined edges is small i.e., the machined surface area ratio to the total core area is high. Considering this, the degradation of the core magnetic properties in the ribs could improve the performance of the machine, and this effect would be more visible when the machine is designed with a higher number of narrow ribs with the adoption of Topology Optimization. The paper aims to propose some guidelines for the simulation of these effects starting from the measurements on defined core samples and then based on the measured results the simulation model should be updated accordingly. The samples are manufactured from several assembled sheets in order to modify the width of the cut area while maintaining the same external geometry.

Performance Analysis of a Rewound Multiphase Synchronous Reluctance Machine

This article analyses the performance of synchronous reluctance motors (SynRMs) when an existing three-phase stator is rewound (REW) to a higher number of phases. The introduced rewinding technique offers an optimized distribution for air-gap flux, higher winding factor, and higher value for the fundamental component of the magnetomotive force with lower harmonics. The number of turns of the proposed multiphase winding is calculated, keeping fixed copper volume. Finite element simulations verified that the torque density of the REW five- and seven-phase SynRMs is enhanced by 6.56% and 3.37%, respectively, over the existing machine under rated conditions. The torque ripple is also reduced by 17.13% and 15.87%, respectively. Furthermore, the efficiency is enhanced with the REW machines by 0.3% at rated condition. Moreover, the torque gain is greatly increased to 23.48% at higher speed (9000 rpm) and the efficiency is also increased by 3%. The main advantage of the REW machine is clearly observed in case of an open-circuit fault. With one-phase opened, the REW machine can work at 78% of the healthy rated torque, while the three-phase machine works at only 43% with a very huge torque ripple about 228%. Experimental measurements are obtained to validate the theoretical work.

Reducing torque pulsations in PMa-SynRM: a way for improving motor performance

This paper aims to evaluate the performance of synchronous reluctance motors assisted by a permanent magnet (PMa-SynRM) focused on efficiency and torque pulsations. PMa-SynRM shows high efficiency and power factor, compared to induction motors (IM), although they have a greater cost. These machines develop relatively high torque ripple, cogging torque, and torque imbalances. Consequently, the electromagnetic torque is reduced, the motor temperature is increased, and mechanical vibrations are induced. The optimal design of the machine structures such as flow barriers, permanent magnets, and stator slots, among others, allow reducing torque pulsations. A comparison is made between different designs of the PMa-SynRM reported in the scientific literature, and the effects on efficiency, torque pulsation, and operating costs are evaluated. A case study on the motor driving the air conditioner blower in a hotel room was made, to determine the best economic variant between IM or PMa-SynRM. A sensitive analysis was made to evaluate several uncertainties. The advantages of using one of the PMa-SynRM analyzed were demonstrated. Also, it was proved that the investment is feasible economically, although NPV and payback are not the best, due to low load factor in inverter-controlled motors in air conditioners.

Impact of Magnetic Core Steel Grade on the Performance of Synchronous Reluctance Motor with Transversally Laminated Anisotropic (TLA) Rotor Core for e-Auto rickshaw Application

This paper investigates the complete performance impact analysis of Synchronous Reluctance Motor (SynRM) designed for an electric Auto Rickshaw application. Here, different magnetic core steel grades are used for the same motor geometry with the TLA rotor. As it is an electric traction application, proper operation of the motor under various operating specifications is critical. Therefore, a thorough study is conducted using the finite-element method combined with an experiment-based magnetic material model at rated speed. Based on the magnetization and hysteresis characteristics of the steel sheets, variations on the performance indexes such as the average torques, torque ripples, and iron losses by using a different stator and rotor materials are investigated. Some valuable comparison results are provided through simulation and experimental validation results are shown with a prototype built.

An Improved Torque Density Synchronous Reluctance Machine With a Combined Star–Delta Winding Layout

This paper investigates the performance of synchronous reluctance motors when the stator is equipped with a combined star–delta winding layout. The conventional star winding is used as a benchmark in this study to compare different possible single-layer winding layouts. Among these different winding layouts, those which maximize the fundamental magneto-motive force component are selected. A simple mathematical formula is then derived to calculate the equivalent winding factor for different shares between star and delta subwindings. It has been proved that for the same copper volume and line current magnitude, the star–delta connection can offer an enhancement in the torque density of approximately 5.2% over the conventional star case under rated conditions. However, this gain is affected by the employed number of poles and stator slots. On the other hand, the effect of the winding layout on either power factor or core loss can be merely neglected over a wide range of speeds and currents. Nevertheless, the machine efficiency under a combined star–delta connection is relatively improved under light loading as a result to the machine torque/current ratio enhancement. The theoretical findings are experimentally validated using two identical 5.5 kW prototype machines, having star and combined star–delta winding connections.

Direct Torque and Flux Control of a Four-Switch Three-Phase Inverter-Fed Synchronous Reluctance Motor Drives

This paper presents an application of direct torque and flux control (DTFC) for a four-switch three-phase inverter (FSTPI)-fed synchronous reluctance motor (SynRM) in which the saturation and iron losses' effects are involved in the machine control modeling. The DTFC switching technique for the SynRM fed by FSTPI in low-power and low-cost applications is implemented by imitating the six-switch three-phase inverter (SSTPI). By considering equal effective vectors depicted in SSTPI, the αβ stationary reference frame is represented by using six sectors. Similarly, the voltage space vector formation is constructed in FSTPI. Accordingly the SynRM performance under DTFC is precisely analyzed by considering the saturation and iron losses' effects. The DTFC behavior based on SSTPI- and FSTPI-fed SynRM is evaluated using Simulink benchmark. At different operating conditions, further simulation and experimental results of DTFC based on FSTPI dynamically confirm the effectiveness of the proposed control application on the SynRM.

Combined Star-Delta Windings to Improve Synchronous Reluctance Motor Performance

This paper analyzes and compares the synchronous reluctance motor (SynRM) performance for a conventional star winding and for a combined star-delta connected winding under healthy and faulty conditions. The finite element method is used to simulate the SynRM characteristics in case of normal star and in case of combined star-delta connected windings. For the healthy case, it was found that for the same current, the SynRM output power increased by about 5% for the star-delta connected windings compared with the conventional star connection. Moreover, the efficiency increased slightly by 0.20%. Probably the strongest advantage of the combined star-delta winding is observed when a phase fault occurs. When one phase is missing, for the same current, the star-delta connected motor keeps 80% of the rated torque in the healthy case, while the star connected motor only keeps 40%. Furthermore, the torque ripple of the star wound machine is extremely high in case of a missing phase, compared to the star-delta wound machine. Simulation results were validated by experimental results to show the effectiveness of the star-delta connected windings on the SynRM.

Improved Accuracy for Performance Evaluation of Synchronous Reluctance Motor

This paper develops an approach that is capable of accurately predicting the performance of synchronous reluctance motors (SynRMs). The SynRMs receive increasing attention and have been used in many industrial applications. The 2-D finite element analysis (FEA) is usually considered to be competent for design and analysis of SynRMs. However, the power factor of SynRMs is likely to be considerably overestimated. This would then lead to an underestimation of current required and cause problems for the design of electronic drivers. Compensation should be made to improve the accuracy of the analysis for SynRMs although there does not seem to be a solution put forward so far. The research in this paper shows that the exclusion of end turn leakage inductances in 2-D analysis is a key factor to cause such a significant difference. To resolve this problem, this paper analytically calculates the end turn leakage inductance, which is then incorporated into the 2-D FEA. The developed method is found to agree well with the experimental results, and it significantly improves the design accuracy and efficiency using only the 2-D FEA.

Synchronous Reluctance Motor Performance Based on Different Electrical Steel Grades

This paper investigates the influence of various electrical steel grades on the torque and efficiency of synchronous reluctance motors (SynRMs). Four different steel grades are studied for the same motor geometry. A finite-element method is combined with an experiment-based magnetic material model to study the effect of the four steel grades on the performance of the SynRM. On the one hand, there is a negligible effect on the torque ripple because this ripple depends mainly on the motor geometry. On the other hand, it was found that the material properties have an obvious effect on the SynRM efficiency and output power. Evidently, the low loss grades result in higher efficiency: 9% point higher for NO20 compared with M600-100A. One of the four considered grades is designed to have a higher flux density in the useful magnetic field range (a few hundreds to a few thousand amperes per meter). This grade has somewhat lower efficiency, but results in a higher saliency ratio and an 8% higher torque output compared with the worst grade. Some experimental validation results are shown.

Passive adaptive control of chaos in synchronous reluctance motor

The performance of synchronous reluctance motor (SynRM) degrades due to chaos when its systemic parameters fall into a certain area. To control the undesirable chaos in SynRM, a passive control law is presented in this paper, which transforms the chaotic SynRM into an equivalent passive system. It is proved that the equivalent system can be asymptotically stabilized at the set equilibrium point, namely, chaos in SynRM can be controlled. Moreover, in order to eliminate the influence of undeterministic parameters, an adaptive law is introduced into the designed controller. Computer simulation results show that the proposed controller is very effective and robust against the uncertainties in systemic parameters. The present study may help to maintain the secure operation of industrial servo drive system.

Design Optimization of ALA Rotor SynRM Drives Using T-AI-EM Environment

An integrated team artificial-intelligence electromagnetic (T-AI-EM) environment is developed to accurately determine the performance of synchronous reluctance motors (SynRM) with axially laminated anisotropic (ALA) rotor configurations. This identifier coupled to a Fuzzy Logic optimization model is used to predict an optimal design of the machine for any given input torque. The main objective of this optimization is to minimize the torque ripple, as well as Ohmic and core losses at a given torque-speed condition. This environment is applied for the characterization and design optimization of a prototype 100-kW, 6000-rev/min ALA Rotor SynRM drive system for traction applications. The T-AI-EM environment resulted in an optimized machine design. The simulation results were compared to measured performance data for verification

Effects of uncompensated vector control on synchronous reluctance motor performance

The performance of a synchronous reluctance motor digital controller based on a saturated dq model without compensation for slotting and iron loss influences is investigated. The model predictions for the machine torque characteristics at various speeds including standstill, and the effects of using simplified control strategies are verified by experimental results. Issues related to the low cost software implementation of the control algorithm are discussed. Quality speed control of an axially-laminated machine has been achieved.