Search results for "circuit"
showing 10 items of 936 documents
Four-Level Three-Phase Inverter With Reduced Component Count for Low and Medium Voltage Applications
2021
This paper proposes a novel three-phase topology with a reduced component count for low- and medium-voltage systems. It requires three bidirectional switches and twelve unidirectional switches for producing four-level voltages without using flying capacitors or clamping diodes, reducing the size, cost, and losses. Removing flying capacitors and clamping diodes allows it to simplify control algorithms and increase the reliability, efficiency, and lifetime. A modified low-frequency modulation (LFM) scheme is developed and implemented on the proposed topology to produce a staircase voltage with four steps. Further, a level-shifted pulse width modulation (LSPWM) is used to reduce the filter siz…
Field Reconstruction for Modeling Multiple Faults in Permanent Magnet Synchronous Motors in Transient States
2021
Conventional field reconstruction model (FRM) for electrical machines has proved its main strength in efficient computations of magnetic fields and forces in healthy permanent magnet synchronous machines (PMSM) or faulty machines in steady states. This study aims to develop a magnet library of different magnet defects and include inter-turn short-circuit (ITSC) in the FRM for PMSM. The developed FRM can model a combination fault between ITSC, and magnet defect in a PMSM in transient states. Within the framework, an 8-turn ITSC was modelled in both finite element analysis (FEA) and FRM, and then identified by the extended Park’s vector approach. The air-gap magnetic field reproduced b…
Generation of nonlinear current-voltage characteristics. A general method
2002
International audience; A general method allowing to construct nonlinear resistors with arbitrary current-voltage (I-V) characteristics is proposed. The example of a cubic I-V characteristic is presented showing a perfect agreement between the theoretical desired resistor and its electronic realization based on analog multipliers.
Efficiency Control for Permanent Magnet Synchronous Generators
2006
In this paper a control algorithm for the efficiency improvement of permanent magnet synchronous generators (PMSG) is presented. The proposed algorithm reduces the losses of the generator without affecting its performances. In details, after a description of a dynamic model of the PMSG, which has been purposely modified in order to take into account the iron losses, the basic equations and the constraints to obtain the loss minimization are presented and discussed. Some simulations of a specific PMSG employing the proposed algorithm are performed. The results of these simulations show that enhancement of the efficiency up to 3 % can be reached in comparison to a PMSG using a traditional con…
An approach to the optimum design of the magnetic circuit of a PM linear electrical generator driven by stochastical forces
2006
Linear electrical generator has been recently studied for the exploitation of sea waves energy. In order to maximize the energy extraction, the stochastic features of the energy source must be included in the mathematical model of the system. A PM linear electrical generator has been designed and built. The design has been optimized by including in the mathematical model used for the optimization the following aspects: 1. the dynamic and stochastic features of the waves; 2. a dynamic model of the hydraulic conversion system; 3. a parametric circuit model of the magnetic circuit as well as of the electric windings; 4. a circuit model of the power electronics converter used to connect the gen…
Adoption of bonded magnets in place of sintered NdFeB: Performance and economic considerations on a small power generator
2015
Bonded magnets are giving promising results when adopted to replace expensive rare earth magnets. The possibility to “modulate” the magnetic characteristics by varying the binder percentage allows the opening of new lines of investigation and to face the problem of rare earths cost. In the paper a small power generator prototype has been equipped with bonded magnets realized in the Authors' Laboratories; it has been tested and compared with the original generator mounting NdFeB sintered magnets. FEM simulations are validated by means of experimental tests. Economic comparisons are proposed.
Minimization of detent force in a 1 kW linear permanent magnet generator for the conversion of sea waves energy: Numerical and experimental validation
2015
Linear permanent magnet generators are widely considered for the direct conversion of energy contained in sea waves [1-3]. Both planar and tubular structures have been proposed [4-6] and all these structures present several advantages: relative high efficiency, simplicity of the structures, high sturdiness. However, as all other linear machines they present some drawbacks: oscillations in the movement, distortion in the generated electromotive force (emf), etc. In this paper we focus our attention on the parasitic oscillations of the translator which are caused by the presence of a high detent force. Detent force is generated by the fact that magnetic energy presents a minimum when the leng…
Voltage stability of Small Hydro Generator Based DC Microgrid
2019
Hydro energy is the vigorous form of renewable energy sources (RES) to generate electricity. It is considered to be an efficient source among the RES due to its abundant potential. Based on the scale at which the power has been generated, operating head, hydro generators are classified into large, small, micro, pico generators. In this paper, a hand in hand approach of inner and outer control loop strategy is proposed to accomplish the voltage stability of a small hydro generator based DC microgrid (MG). The DC MG considered in this paper is operating under the unusual condition where solar, wind and main grid are off due to irregularity. Moreover, the load is of varying nature. Outer contr…
On the Parameterization of Cartesian Genetic Programming
2020
In this work, we present a detailed analysis of Cartesian Genetic Programming (CGP) parametrization of the selection scheme ($\mu+\lambda$), and the levels back parameter l. We also investigate CGP’s mutation operator by decomposing it into a self-recombination, node function mutation, and inactive gene randomization operators. We perform experiments in the Boolean and symbolic regression domains with which we contribute to the knowledge about efficient parametrization of two essential parameters of CGP and the mutation operator.
Suppression law of quantum states in a 3D photonic fast Fourier transform chip
2015
The identification of phenomena able to pinpoint quantum interference is attracting large interest. Indeed, a generalization of the Hong–Ou–Mandel effect valid for any number of photons and optical modes would represent an important leap ahead both from a fundamental perspective and for practical applications, such as certification of photonic quantum devices, whose computational speedup is expected to depend critically on multi-particle interference. Quantum distinctive features have been predicted for many particles injected into multimode interferometers implementing the Fourier transform over the optical modes. Here we develop a scalable approach for the implementation of the fast Fouri…