1,720,970 research outputs found
Comprehensive Analysis of Extended Electro Motive Force Observers for Position Estimation in Interior Permanent Magnet Synchronous Machines
No full textExtended Electro Motive Force observers exhibit good performances at medium and high speeds. However, voltage and current errors, together with parameter uncertainties, lead to inaccurate rotor position estimation. Thus, this paper proposes a novel analytical approach to identify estimated position errors of Extended Electro Motive Force Observers in both the stationary and the estimated synchronous reference frames. A unified analytical framework is presented, that allows to derive a closed-form expression for these errors in both frames. Steady state errors are extensively investigated with respect to stator resistance mismatch, inductances mismatch, voltage distortion, and current measurement errors. Results are validated through simulations
A saturation model based on a simplified equivalent magnetic circuit for permanent magnet machines
No full textThis paper proposes an explicit mathematical model to describe the nonlinear behavior of the permanent magnet synchronous reluctance machine. Although different models for the synchronous reluctance machines are available, extending them to the case of the permanent magnet machine is not trivial due to the effect of the permanent magnets on the rib saturation. This work uses a simplified equivalent magnetic circuit to derive the structure of the proposed model. A nonlinear reluctance is introduced to model the rib saturation. It can be added to the existing model for the synchronous reluctance machine to take into account the effect of the permanent magnets. A simple fitting procedure based on the steepest descent method is proposed to estimate the parameters of the model
Design of a high speed printed circuit board coreless axial flux permanent magnet machine
No full textThe use of printed circuit board stators in coreless axial flux permanent magnet machines allows to reduce manufacturing costs and to eliminate the main drawbacks of traditional implementations using Litz wire. This work investigates the design of a coreless axial flux permanent magnet machine having printed circuit board concentrated windings. The field model of the coreless machine is reviewed to obtain closed-form equations for torque, eddy current loss and circulating currents loss are presented. Furthermore, cardinal geometrical parameters of the printed circuit board stator and the latest manufacturing possibilities are investigated, followed by the presentation of important machine design details
High efficiency-low cost powertrain for urban electric vehicle
No full textA Cooperation Project between: CR-ENEA "Casaccia" (Italian Governmental Agency for the Environment and Alternative Energy - Electric Vehicle division), Semikron Italy and University of Rome "Sapienza", started in 2006 to design a Full-Electric City-Car with the lowest possible specific consumption and using the technology which showed the best cost/performance ratio. The result is an High Efficiency Dual-Feed City-Car (4kW Permanent Magnet Electric Motors, one in each Front Wheel). The P.M. Motors are powered by two Custom Specific SEMIKRON Power MOSFET Modules, which use the proprietary "Pressure Technology" and are controlled by Digital Signal Processors (DSPs). No gearing, neither mechanical coupling are necessary. Battery Pack during tests and races were Lead Acid, boosted by Ultracapacitor system to improve performances. UltraCapacitor Units, are mounted according to [1], [2]. In this paper has been demonstrated that consumption per kilometer was reduced over 10% using this solution. Tests have been certified in the ENEA Test bench and during the Formula ATA 2008 competition at the FIAT Research Centre Facility, where the Car won the Second Prize and proved the reliability
A Comparative Study of Stator Winding Technologies for Coreless Axial Flux Permanent Magnet Machines
No full textRecently, axial flux permanent magnet machines with coreless windings have been proposed for many applications, from low-speed servo systems to high-speed electric propulsion. These machines have zero cogging torque and core losses, a highly linear behaviour, and remarkable overload capabilities. Conversely, thermal behaviour, efficiency, torque density and power density strongly depend on the specific stator winding technology. This paper reviews stator winding technologies for coreless axial flux permanent magnet (AFPM) machines, focusing on their potential benefits and limitations. Additional contributions include the analysis and comparison of different winding solutions for low-speed and high-speed machines. The presented results can be used as guidelines for the selection of the most appropriate winding technology for a number of practical applications
Design of a Printed Circuit Board Axial Flux Permanent Magnet Machine for High Speed Applications
No full textRecently, printed circuit board (PCB) stators have been proposed for coreless axial flux permanent magnet machines to reduce manufacturing costs and eliminate some of the drawbacks of traditional Litz-wire-based stators. However, their design presents significant challenges. Firstly, the PCB copper traces are exposed to the rotating air-gap field, which causes significant high-speed AC losses. Secondly, standard PCBs hardly satisfy stator winding requirements since the achievable copper fill factor is rather limited. In order to address these issues, the paper proposes a bespoke machine design methodology which relies on original closed-form expressions for eddy and circulating current losses. Additionally, the most recent PCB technological developments are considered in the determination of manufacturing constraints. A case study is provided for a 1 kW, 7500 rpm machine to validate the design method. An original winding layout is proposed to suppress circulating losses. Finally, an extensive set of experimental tests on a full-scale prototype is reported
Evaluation of extended electro motive force observer dynamic performances using complex vectors
No full textExtended Electro Motive Force Observers in the estimated synchronous reference frame allow to estimate rotor position at medium and high speeds for Interior Permanent Magnet Synchronous Machines. This paper focuses on the analysis of the dynamic performances of these observers. Use of complex vector modeling allows to demonstrate that these performances are speed dependent. In order to overcome this problem, a Complex Vector Observer is proposed. It is proven that this structure achieves good robustness against load torque and speed variations over different operating conditions. An improved phase detector is also presented, to solve the common speed reversal problems of the back-EMF based methods
A One-Body, Laminated-Rotor Flywheel Switched Reluctance Machine for Energy Storage: Design Trade-Offs
No full textA critical aspect of distributed generation systems focuses on the installation of Electrical Energy Storage Systems in customer-side facilities. In this scenario, flywheel technology is challenged to provide high levels of safety, compactness and competitive cost. This work presents a novel, one-body flywheel scheme based on a switched reluctance machine, whose laminated rotor fulfils both the motor/generator and energy storage functions. The one-body architecture enhances compactness and robustness, whereas the laminated rotor ensures high safety. The design of this flywheel scheme is characterised by a widely different set of trade-offs compared to conventional schemes. In order to prove the feasibility of the proposed scheme and to highlight its design trade-offs, a 60kW, 2.2kWh one-body flywheel is presented as a case study, along with some preliminary experimental results
Impact of closed loop pole placement on the low speed performance of VFDs using low-resolution position sensors
No full textThe main aim of this paper is to investigate the influence of speed loop pole locations on command tracking and torque disturbance rejection at low speed in variable speed drives using low-resolution position sensors. The study considers a fixed position speed estimation algorithm, and experimental tests have been conducted on a 3kW permanent magnet synchronous motor drive. The experimental results validate the effectiveness and feasibility of the theoretical study
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