1,720,965 research outputs found
Integral-resonant control for stand-alone voltage source inverters
No full textThis study deals with a newly-conceived voltage control method for three-phase four-leg voltage source inverters
(VSIs) which are being required in autonomous power generating units devoted to supply both three-phase and single-phase electrical loads in four-wire electric power distribution systems. To deal with VSI operating conditions providing three-phase voltage supply of both unbalanced loads and non-linear loads, an integral + resonant (I + R) voltage control structure is discussed and experimentally verified by means of a 25 kVA rated power converter prototype. It is shown that the proposed voltage control allows simplifying the overall control configuration, achieving zero-overhead power factor regulation and fast compensation of load unbalances. Further to that, a complete current limiting strategy is described and tested under different load conditions
LC Filter Design for On-grid and Off-grid Distributed Generating Units
Full text linkThis paper deals with the design procedure of an LC-based output filter for three-phase inverters to be used in both
off-grid and on-grid scenarios. The aim of this procedure is to provide guidelines and component selection criteria for reducing the inverter output switching ripple in order to limit the interaction with the control algorithm and to increase the filter stability. A suitable combination of resistive and reactive components is used to realize the complete filter structure. The proposed procedure is applied to the design of the output power filter for a 40-kVA three-phase inverter
High-Speed Electric Drive for Exhaust Gas Energy Recovery Applications
No full textHigh-speed electric drives play an important role in the field of power generating units on board vehicles and aircrafts. This paper deals with the solutions for developing the direct coupled electric drive to be used in combination with a radial turbo-expander for exhaust energy recovery in automotive applications. The descriptions of prototypal realization of both the axial-flux permanent-magnet (PM) generator and the three-level boost-rectifier converter, which results as the preferred topology for the controlled rectifier, are given. The high rotational speed of the direct-driven PM generator results in high electric fundamental frequency also, which is challenging for the electric drive control issues. Results of the electric drive prototype experimental activity are finally presented
Performance Evaluation of Converter Topologies for High Speed Starter/Generator in Aircraft Applications
No full textA distributed model predictive control strategy for back-to-back converters
No full textIn recent years, model predictive control (MPC) has been successfully used for the control of power electronics converters with different topologies and for different applications. MPC offers many advantages over more traditional control techniques such as the ability to avoid cascaded control loops, easy inclusion of constraint, and fast transient response. On the other hand, the controller computational burden increases exponentially with the system complexity and may result in an unfeasible realization on modern digital control boards. This paper proposes a novel distributed MPC (DMPC), which is able to achieve the same performance of the classical MPC while reducing the computational requirements of its implementation. The proposed control approach is tested on a ac/ac converter in a back-to-back configuration used for power flow management. Simulation results are provided and validated through experimental testing in several operating conditions. © 1982-2012 IEEE
Modeling of Voltage Source Inverter having Active Split DC-Bus for Supply of Four-Wire Electrical Utility Systems
No full textHigh-Speed Synchronous Reluctance Machines: Materials Selection and Performance Boundaries
No full textThis article presents a comprehensive comparative design exercise of synchronous reluctance (SyR) machines considering different soft magnetic materials and a wide range of speeds. First, a general design methodology able to consider all the consequences of selecting different materials is presented. In fact, magnetic nonlinearities, rotor structural limitations, and the rise of both stator and rotor iron losses are all considered. The adopted design approach allows achieving optimal stator and rotor geometries balancing all these competitive multiphysics aspects and keeping constant the cooling system capability. Both silicon–iron (SiFe) and cobalt–iron (CoFe) alloys with optimized magnetic and mechanical performance are examined to assess the maximum capabilities achievable with an SyR machine technology. The adoption of CoFe alloys leads to machines that outperform the SiFe counterparts up to a certain speed, above which, machines with SiFe provide better performance. Indeed, in the lower speed range, the effect of the higher saturation flux density of the CoFe materials is dominant, while for higher design speeds, their higher iron losses and lower yield strength, with respect to the SiFe ones, make the latter more convenient. All the design considerations are finally validated by comparing the predicted performance with the experimental test results on a 6.5-kW, 80-kr/min SyR machine prototype
Zero-Sequence Voltage Elimination for Dual-Fed Common DC-Link Open-End Winding PMSM High-Speed Starter-Generator - Part I: Modulation
Full text link© 1972-2012 IEEE. In this paper, a dual-fed (DF) common dc-link topology open-end winding permanent magnet synchronous motor for aircraft high-speed starter-generator application is considered. While on one hand the common dc bus configuration significantly simplifies and reduces the costs of the topology, on the other hand it allows the zero-sequence current (ZSC) to flow freely in the system. High-speed machines are characterized by low phase inductance, which implies low zero-sequence impedance. A small time constant of the zero-sequence circuit produces a high-frequency, high-intensity ZSC ripple with the risk of harming the switching devices. This paper presents a novel hybrid space vector pulsewidth modulation that allows to instantaneously eliminate the zero-sequence voltage (ZSV) produced by the two voltage source converters (VSCs) by square wave modulating one of the two VSCs. The non-sinusoidal machine back electromotive force (EMF) has been considered and the effect of the converters' dead time on the ZSV has been analyzed. The square-wave-modulated VSC uses insulated-gate bipolar transistor (IGBT) devices, whereas the other uses Silicon Carbide (SiC) technology. The proposed topology is tested through both simulations and experiments
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