Olivian Chiver

Considerations about power system grounding for different soil structure

The paper presents some considerations about power system grounding based on analytical computation, Finite Element Analysis (FEA) combined with neural network. There are studied vertical rods buried on different depth in homogenous and double-layer soil. First, the analytical solutions are compared with the numerical results for certifying the FEA settings then, different configurations for electrodes in different soil structures were analyzed and the results were interpreted using neuronal network. This approach offer solutions for any configurations in less time than FEA alone.

Transient analysis of wound rotor synchronous motor synchronisation using finite elements method

The paper deals with wound rotor synchronous motor synchronization when the motor starts in asynchronous regime. “The fineness” of the synchronization will be studied in terms of the following parameters: the value of the starting resistance, the value of the DC voltage and the position of the rotor against magnetic field of the stator at the moment when the excitation winding is connected to the DC voltage. The transient analysis was carried out using a program based on finite elements method (FEM).

Capacitive touch sensors sensibility for different ground hatch and shield electrode structures

In this paper we perform a study regarding capacitive touch sensors, structured on Finite Element Method applied on electrostatic field simulation. The behavior of the sensors for different architecture regarding: the electrodes, the ground planes or/and the shields, the overlay thickness and the influences of the nearby potentials is modeled and interpreted. The right setup of the Finite Element Method software, i.e. Finite Element Method Magnetics, was confirmed trough analytical solutions and the validation of the results was done based on data provided by manufacturers of capacitive touch components.

Optimised methodology for stepper motor simulation

The paper presents the effort of the authors to minimize the computational time and resources brought in electrical machines conception, design and analyses. The proposed methodology is a mixture between Finite Element Analysis and neural network interpretation of resulting data, with important conclusions about the minimum number of inputs asked by the desired accuracy. The methodology is illustrated on stepper motor due to its important place in positioning systems, computer and peripherals architecture, electric vehicles and because its significant interest in researchers works.

Frequency domain numerical analysis of rotor cage induction motor

This paper proposes a method of finite elements analysis (FEA) of the rotor cage induction motor. In case of an induction motor supplied with constant voltage, the current during starting process is not constant. For that reason, FEA in frequency domain at constant current is not appropriate for direct start simulation. A motion analysis is required, the rotor speed being computed according to magnetic field values. The main disadvantages are that such analysis requires considerable time and hardware/software resources. In order to eliminate these shortcomings, this paper proposes a frequency domain analysis, stator winding being fed with constant (nominal) voltage. The torque-slip, current-slip curves and the parameters variation during direct start process can be obtained, without requiring however a numerical analysis with motion. The results obtained by this method are compared to those given by equivalent circuit parameters and by measurements.

Utilization of Finite Elements Programs and Matlab Simulink in the Study of a Special Electrical Motor

This paper presents the study of a single-phase synchronous motor with permanent magnets (PM) using some computer programs. This motor type is used especially in household applications, and it has a low power. It is known that PM synchronous motors have a great advantage consisting in the lack of rotor losses. For this motor the starting problem has been solved performing a variable air gap under polar shoes, what determine the occurrence of the starting torque due to the fact that the axis of the rotor field created by PM in the rest position differs from the axis of the stator. First the parameters of the motor have been determined by tests and finite elements (FE) simulations, without knowing the properties of the PM. At the beginning magnetostatic FE simulations have been performed and then in magnetodynamic regime. The obtained results in the two regimes are closed. Secondly, with the determined parameters, a Matlab Simulink model has been realized (this being the final goal), and the dynamic regime of the motor has been studied. The results regarding the motor speed in starting process, the current variation, are also presented and discussed.

Finite Element Method Combined with Neural Networks for Power System Grounding Investigation

Even in homogenous soil and for simple geometrical structure the analytical design of a grounding system is a complex and not very accurate procedure. Using Finite Element Analysis (FEA) it can perform a precise design for complex grounding systems but with important hardware resources and time consumption. This paper proposes a methodology for power system grounding design, directed to ensure the advantages of the FEA but without its disadvantages. This is realized by adding the function emulation using neural networks. The vertical rod, buried in inhomogeneous soil is the subject of this presentation. Consequently, the first step was to perform FEA for a large number of configurations: different types of vertical rods connected to the surface, buried at various depths in different double-layer soil structures. Then, the results have been interpreted through a multi-layer perceptron (MLP) with one hidden layer. A compromise between the number of inputs and precision have been tested, in order to define a minimum number of FEA required to obtain an acceptable grounding system design, i.e. a desired grounding resistance, for any combinations of the geometrical and material parameters. The validation of the methodology was done based on data reported in various research works.

Single-phase PM synchronous motor simulation with Matlab/Simulink

The permanent magnet (PM) synchronous motors have a major advantage compared to the asynchronous motors, namely that there are no losses in the rotor. As regarding the single-phase motors must be considered the possibility to obtain the starting torque. A simple and inexpensive constructive solution is the motor with tapered air-gap, which can develop a starting torque (although specific starting torque is small) in a well-defined direction, simply by powering the stator winding from the network of industrial frequency. Starting torque occurs due to the fact that the axis of the rotor field created by PM in the rest position differs from the axis of the stator because of the tapered air gap. Therefore this motor is more often used in low power household appliances. The development and the implementation in Matlab / Simulink of the motor model will be presented in this paper. The model is based on a mathematical model with lumped parameters, parameters that are determined through calculations and finite elements analysis. The motor behavior will be studied, both in stationary and dynamic operation. The accuracy of the model is verified by comparing simulation results with results obtained by measurements.

Identification of parameters of single-phase PM synchronous motor

This paper will conduct a study on determining the parameters of a single-phase synchronous motor with permanent magnets (PM). It is a low power motor used especially in household applications. The goal is the determination of the motor parameters by tests and simulations, without knowing the properties of the rotor permanent magnet. There are known all geometric dimensions and the number of turns of the stator winding.

Considerations about medium voltage SF 6 switch disconnector framework design based on 3D electrostatic FEA

The paper presents some considerations regarding the framework design for a medium voltage SF6 switch disconnector based on 3D Finite Element Method Simulation. The conflict between dielectric design, at one side and technologically challenges, costs and dimensions on the other side is the main issue of this research. The analytically designed configuration is implemented in CST Studio Suite environment and the electric field intensity is evaluated in order to suggest some advises in switchgear design.