Costin Cepisca

Contributions Regarding the Principles of the Minimum Dissipated Power in Stationary Regime

The use of the power and energy functional in the analysis of the electric circuits makes it possible to appreciate the energetic equilibrium state attained in the circuit at a certain moment. In the present work, a power functional is built and its limit is determined. It is shown that the equilibrium state is one of a minimum energetic state

The Modelling of the Power Factor in Steady State Non Sinusoidal Regime with Mathcad Techniques

The paper presents the results of a new mathematical method to calculate the power factor in the electroenergetical circuits. The relative values which characterize the voltage and current harmonics have been used. The MathCAD example will prove, comparatively, the efficiency and the application of this method

The systematic analysis of the absorbed power in D.C. Networks with modifiable parameters using a new mathematic algorithm

The paper presents a new systematic analysis method in order to calculate the absorbed power in D.C. networks with modifiable parameters. The relation between the change in one or all the resistances of the networks, and the variation of total absorbed power are discussed using the Lagrangepsilas multipliers, and the bilinear theorem. The results obtained with the dedicated software Mathematica 6.0 are useful for establishing the variation limits of absorbed power.

Optimization and monitoring energy consumption from small industrial consumers

Urgent need for energy savings involves introduction of intelligent monitoring and control networks for industrial consumers, including small and medium ones. New functions of smart grid and energy storage quality monitoring systems make up the path for new consumption ways. This paper presents a system solution that optimizes electricity consumption from small industrial customers through local control and also introducing renewable energies in the presented solution.

Aspects of metrological calibration of power quality analyzers

This paper presents some aspects of power analyzers utilization, related with your calibration by metrological laboratory. The full metrological characterization of power analyzers is a difficult technical process because the specifications in related standard are minimal. After a short presentation of parameters and measurement methods recommended by the important standards in the field of power quality, CEI EN 50160 and CEI EN 61000-4030, study of uncertainty propagation related to test calibration, this document describes the instruments configuration and evaluation of measurement errors and uncertainties for one parameter, voltage in sinusoidal and non-sinusoidal regime.

Power quality monitoring systems for smart grid networks

The momentum of today is focused on smart grid facilities that allow green energies to be used in electrical networks. But an important issue is to have powerful tools at hand able to measure power quality parameters in a flexible way in such grids. This paper present a flexible system designed and implemented to monitor power quality parameters in the power grid. Not only real time monitoring was taken into account but also a build-in database was designed for inspections and long term statistics. Different measurement standards can be used in order to provide flexible information in energy measurements.

Mathematical solution to solve the minimum power point problem for DC circuits

The use of the power functional in the analysis of the electric circuits makes it possible to appreciate the energetic equilibrium state attained in the circuit at a certain moment. The basic circuit laws of electric circuits in stationary regime are interpreted in this paper by defining suitable functional in terms of power for DC circuit. It is shown that the minimum power determined by taking the derivative of these functional verifies the first Kirchhoffs law. This allows interpreting the circuit equations by using the second Kirchhoffs law and the principle of minimum power. A mathematical solution is used in order to determine the minimum power point for DC circuits. Numerical algorithm is implemented by used Matlab for validate the theory.

About the Efficiency of Real Time Sequences FFT Computing

Fast Fourier transform (FFT) computing may improved using two ways: the first way consist in packing two separate real functions into the complex input array in such a way that their individual transforms can be separated from the result; the second method used to improve the FFT computation consists in packing the real input of length N array cleverly, without extra zeros, into a complex array having half of its length. In this paper an analysis of a combination of these two methods is performed and also a numerical simulation in order to detect the right conditions in which this method is applicable.

A non-contact heart-rate monitoring system for long-term assessments of HRV

In this paper, we propose a two electrodes configuration for noncontact long-term cardiac monitoring. Our system was designed as an alternative to Holter devices. Unlike a traditional long-term monitoring equipment, our system is stationary and non-contact, the cardiac signal is acquired through a capacitive coupling between the sensor and the subjects body. The proposed system is the first prototype and a stepping stone in the development of a future bio-monitorisation platform dedicated to non-contact cardio-respiratory investigations.

Multiple sensor software and hardware architecture for field robots

Applications in Field Robotics often require synchronous acquiring various environment information using multiple sensors and devices, including digital cameras. For such applications, this paper proposes a software architecture that is designed to cope with large amount of mixed type data, acquired with various sample times, and gathered from multiple sensors and sensing devices. By allowing the integration of cameras having widely available communication interfaces, such as USB and Ethernet, the presented architecture is intended to allow a cost-effective and flexible robotic system configuration, providing consistent data and loss-less images to be further used in automated data processing. The paper presents the software design, which was implemented in LabVIEW environment, and an illustrative hardware configuration.