Showing papers in "Automatika: Journal for Control, Measurement, Electronics, Computing and Communications in 2006"

High Efficiency DC-to-AC Power Inverter with Special DC Interface

Abstract: In case of medium voltage (several tens up to hundred volts on DC-side) solar inverter applications, a DC-to-DC converter for voltage level adaptation is required in series of the DC-to-AC inverter. This leads to a two-stage concept with accumulation of the losses. In our case a concept was chosen where the efficiency of each stage is maximized by using the best topology. The given requirements make the application of a non-isolated design imperative to avoid additional transformer losses. In this paper a 60V–120V DC (input) to 230V AC (output) / 1kW converter with minimal conversion losses is derived. A simple modification in the inverter's output section leads to a significant improvement of the losses in the inverter system. Only three additional components (two diodes and one inductor) are necessary to optimize the inverter's power stage. The topology presented here shows a remarkable improvement of the switching losses and significantly reduced EMC. It is well-suited for solar power inverter applications.

Finite Element Approach to Calculation of Parameters of an Interior Permanent Magnet Motor

Abstract: UDK 621.313.82:519.6 IFAC 5.5.4 Original scientific paper A method for calculation of parameters of an interior permanent magnet (IPM) motor at any operating point using 2-D finite element method is presented. This approach is suited to be used in the design stage where it is necessary to determine the motor parameters, namely inductances, which are simultaneously a function on motor dimensions and terminal voltage constraints. An analytical technique based on a 3-D geometric model of the end winding region in which each coil is modeled as a set of serially connected straight filaments has been used for calculation of the end winding leakage inductance. The calculation of the mutual inductance of the end coils is based on the multiple solutions of the Neumann integral. This approach to calculation of motor parameters has been applied in the design of a 1.65 kW IPM motor for which a prototype has been built and tested.

An Algorithm for Deadlock Prevention Based on Iterative Siphon Control of Petri Net

Abstract: This paper presents a formal calculation method of a deadlock prevention supervisor by the use of Petri nets. The proposed algorithm uses reachability tree to detect deadlock state and iterative siphon control method to synthesize the deadlock prevention supervisor. Such supervisor is maximally permissive and consists of minimal number of control places. The algorithm is intended for reversible or partially reversible P-T Petri net, but it can also be applied to Ordinary Petri nets. The calculation of the supervisor is illustrated by two examples. The first example shows the synthesis of deadlock prevention supervisor in a manufacturing system consisting of three conveyors and three robots, where the deadlock can occur due to concurrent requests of the conveyors for the robot engagements and unpredictable duration of those engagements. The second example shows the synthesis of deadlock prevention supervisor in a marine traffic system, where dangerous vessel deadlock situations may occur in case of vessels’ irregular motion through the system. To avoid this, the vessel traffic is supervised and controlled by traffic lights using the deadlock prevention supervisor, which is responsible for vessels’ stopping only in the case of dangerous situation and until this situation elapses.

Ultra Wideband Dipole Antenna Optimization

Abstract: This paper describes optimization of the planar ultra wideband dipole antennas, which are optimized for perfect matching and perfect impulse radiation characteristics. The optimization of the dipole shapes starts from the classical wideband dipoles, especially from elliptical and diamond shapes. These wideband dipoles have been analyzed and optimized with unsatisfactory parameters performance. This paper proposes two optimized dipole structures fulfilling required parameters. Designed antennas could be used as an impulse-shaping filter for forming of transmitted UWB impulse.

Simplified Light Plane Determination during Structured Light Scanning

Abstract: Structured light illumination is a widely spread approach for 3D shape reconstruction. Scanning the scene of interest with hard edge stripe via video projector is a very common implementation. During the scanning light planes are being projected across the space and their positions in time are needed to triangulate 3D position of some point. Traditionally, light plane equation is readily obtained in case of calibrated video projector. This paper presents a method where light plane positions are determined without explicit projector calibration. The comparison of traditional and proposed method showed no difference in terms of reconstruction accuracy. However, there are two major advantages of proposed method: end user can faster start using the system itself and system implementation is easier primarily in software sense. Also, successful method implementation for computer graphic application is shown.

VoIP/PSTN Networks Planning with PlanVoip Application

Abstract: The paper describes the IP network as a basis for the voice services transfer and parameters which influence the quality services level in the voice transfer over the IP network. Among all parameters, the accent is given on delay components, special on variable components. Hereafter is described the application which we have developed for the purpose of the VoIP/PSTN network planning and analyzing. At the end, testing measurements with the developed application are made whereat the influence of the used codec and the link capacity on the subjective score of voice quality (MOS) and on the total delay of voice packet is analyzed. For the purpose of the developed application verification, a comparison analysis of the testing measurements and measurements on the real network is carried out.