1,721,223 research outputs found
An accurate wide-speed range control method of IPMSM considering resistive voltage drop and magnetic saturation
Full text linkThis paper deals with the high accurate current set-points solution for Interior Permanent-Magnet Synchronous Motors (IPMSM) in wide-speed range applications. Considering voltage and current constraints, the operating regions can be divided into Maximum Torque Per Ampere (MTPA), Maximum Current (MC), Field Weakening (FW) and Maximum Torque Per Voltage (MTPV) regions, which requires to solve different non-linear functions in real time to obtain optimal current set-points. Traditional methods including curve-fitting methods and polynomial approximation (PA) methods are not easy to obtain these solutions, especially involving magnetic saturation problems. In this paper, Newton-Raphson (N-R) algorithm for improving the control accuracy of the current set-points is proposed. Meanwhile, parameters influence including magnetic saturation and resistive voltage drop is fully investigated. Compared with PA method, the proposed method is able to converge to accurate solutions in few numbers of iterations with reduced execution time, which can be easily implemented on an off-the-shelf Digital Signal Processor (DSP). Both simulation results and experimental results on an 8kW IPMSM rig are conducted showing good agreement with the expected results. Index Terms-Cross Saturation, flux-weakening control, interior permanent-magnet synchronous motors (IPMSM), magnetic Saturation, Newton-Raphson (N-R) method, resistive voltage drop
Modelling Short and Open Circuit Faults in Permanent Magnet Synchronous Machines using Modelica
No full textAn Analytical-Numerical Approach to Model and Analyse Squirrel Cage Induction Motors
Full text linkNowadays, finite element analysis represents the most accurate tool to analyse electrical machines. However, the time domain resolution of electromagnetic problem, in some cases, requires long simulation time due to the induced nature of the currents. The computational burden increases when the machine features a skewed layout on the stator or rotor structures, since this requires 2D multi-slices approximated analysis or even a full 3D model. In this paper, a general analytical method to model electromagnetic devices is applied to a squirrel cage induction motor featuring a skewed rotor structure. The modelling approach is wisely implemented and adapted to pursue a fair balance between accuracy of the analysis and computational burden, taking advantage of all the symmetries existing in the rotor cage of the machine, aiming to minimize the model complexity. A comparative analysis in term of the inductances between analytical and finite element is proposed. The results provided by the model developed are compared with respect to the corresponding values provided by both finite element and experimental test performed on the reference machine. Such comparisons show that the proposed model is actually able to achieve a pretty good balance between accuracy and computational efficiency
Winding concepts for ultra reliable electrical machines
No full textThis paper investigates two winding concepts for Permanent Magnet (PM) machines used for more electric aircraft systems where reliability is a concern. Analysis is carried out using two different surface mounted PM machines designed for low and high speed applications: a 12 slot, 10 pole machine with concentrated windings for rotorcraft swashplate actuation and a 36-slot 6-pole machine with distributed winding arrangement for an aircraft starter-generator. The impact of the winding arrangement for the low speed machine is investigated with a focus on turn-turn Short-Circuit (SC) faults. Implications of the SC fault and methods to restrain the resulting SC current are discussed. A prognostics method for potential turn-turn SC faults for the high speed application is then investigated. It is shown that potential winding faults can be detected at an early stage of fault inception and thus measures can be taken to limit propagation
Comparison of different methods for incipient fault diagnosis in PMSMs with coaxial insulated windings
No full textEarly detection of incipient faults in AC drives is one of the most difficult challenges for condition monitoring, especially for faults related to insulation degradation of the windings. In low power motors, the insulation degradations are principally due to the steep voltage variations caused by the voltage source converters (VSCs) that drive the machines. In the last years, the possibility to employ coaxial cables in the stator windings has been explored in order to enhance the capacity of the motors to withstand the great values of dv/dt that are achieved by the no-Si based power devices. In this paper a new method to detect the presence of incipient faults in PMSM with coaxial insulated winding is presented and compared with a previous solution. The different methods were extensively evaluated, by means simulations and experimental results, to determine their feasibility to be employed as on-line condition monitoring systems
Closed-form approach for predicting overvoltage transients in cable-fed PWM motor drives for MEA
No full textThe More Electric Aircraft (MEA) concept has set tight constraints for power density and efficiency of electromechanical actuators in aircraft applications. In order to comply with these high power standards, new wide-bandgap (SiC and GaN) semiconductor devices may be exploited. Unfortunately, the extremely short switching times of these devices can easily trigger high frequency ringing voltage at motor terminal in cable-fed PWM motor drives due to pulse reflection. The resultant overvoltage stresses the insulation of stator windings decreasing the motor's lifespan. The most common solutions involve bulky and heavy passive filters, not suitable for MEA design approach, so the overvoltage suppression remains an open question. This paper explores the influence of pulse rising (and falling) time to the magnitude of motor terminal overvoltage through a detailed closed-form analysis of the problem in order to support electrical drive design optimization
On the Use of Topology Optimization for Synchronous Reluctance Machines Design
Full text linkSynchronous reluctance (SynRel) machines are considered one of the promising and cost-effective solutions to many industrial and mobility applications. Nonetheless, achieving an optimal design is challenging due to the complex correlation between geometry and magnetic characteristics. In order to expand the limits formed by template-based geometries, this work approaches the problem by using topology optimization (TO) through the density method (DM). Optimization settings and their effects on results, both in terms of performance and computation time, are studied extensively by performing optimizations on the rotor of a benchmark SynRel machine. In addition, DM-based TO is applied to an existing rotor geometry to assess its use and performance as a design refinement tool. The findings are presented, highlighting several insights into how to apply TO to SynRel machine design and its limitations, boundaries for performance improvements and related computational cost
A Novel Flux Barrier Parametrization for Synchronous Reluctance Machines
Full text linkThis paper presents a novel parametrization for the flux barrier profiles of synchronous reluctance and permanent magnet assisted reluctance machines. In literature there are several methods used to design rotor flux barriers of various types, however the vast majority use only a few parameters to characterize their shape. These approaches are proven to be effective in terms of simplicity and computational burden required to achieve an optimal design. However, simplified parametrizations certainly decrease the degrees of freedom when designing the whole barrier shape. In this paper, an attempt to increase the degrees of freedom, introducing a novel rotor flux barrier parametrization, is presented. The method proposed uses natural splines, defined by the positions of a set of control points, to form the shape of the flux barriers. The spline and state-of-the-art barrier profiles are compared from both electromagnetic and mechanical perspectives. The results of this investigation show that by increasing the degrees of freedom it is possible to obtain better performance characteristics. The proposed parametrization is applied to a 6-pole synchronous reluctance motor and its permanent magnet assisted variant, optimized for a traction application. A prototype has been manufactured and tested to experimentally validate the design methodology
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