The article presents new idea of matrix converter modeling suitable for dynamic states. The representation of converter bi-directional switches allows to separate their conduction and blocking states. The application of the additional discrete variable to the area based single periodical matrix control method made it suitable for application for modeling dynamic processes. The equations describing converter using natural coordinates were formed and specific properties of single periodical control method were used to create hybrid description of the matrix converter as multiport element. The implementation of the symmetrical components method to such description allowed to separate the equations describing the converter into an individual equations for each component. The equation for first order component can be represented by relatively simple equivalent circuit characterizing converter during symmetrical conditions of work.

This paper presents the control and monitoring system of a small hydropower plant (SHP). The control rules of the parameters in that type of objects, their practical realization by a dedicated control system and exemplary operation were described. In the second part the way of algorithm implementation using a modern hardware was presented. The control algorithm implementation from the software point of view was also shown. The paper contains the measurements from the real control and monitoring system of SHP. This SHP contains two permanent magnet (PM) generators of 75 kW electrical power each, which can work at a variable speed.

This paper presents the rules of management of an energy conversion system in a small hydropower plant (SHP). The SHP contains two permanent magnet (PM) generators which can work at a variable speed. In the article the way of obtaining the optimal work characteristic curve is described. To achieve the best efficiency the special methodology of units cooperation is also presented. The theoretic analysis is algorithmizated, implemented and tested in the real object of 150 kW electrical power. The measurement results of this object are presented.

In this paper the computer model of the cage induction machine taking into account magnetic non-linearity is presented. The model contains the mathematical model of the induction machine recorded as an S-function and the connecting blocs attaching the model from one side to the three-phase terminals of the supply system model and from the other to the system of mechanical model. Hence, Sim-Power-Systems and Sim-Mechanics libraries can be used. Such a methodology allows for various drives modelling where the induction machine operates as a motor or a generator and cooperates with power electronics system. Using wide range of SIMULINK possibilities the various control techniques can be applied. Using this methodology the own mathematical models of other electrical machines together with the SIMULINK library models can be used.

Technical condition assessment of induction motor can be done with stator current analysis. This analysis can be done in steady state with FFT transform. Starting current analysis with wavelet transform is a very good method of cage condition assessment. The advantage of this method is that we can observe how characteristic components vary in time. Characteristic fault symptoms can be observed when the machine is working with alternating load which causes rotor’s angular speed and slip change. Transient states when the load changes, occur very often increases the application of thism method. This paper presents the results of application wavelet transform in motor fault diagnostics in transient states.

This paper presents an algorithm that uses the harmonic balance method for finding the steady-state solution in the moment of excited synchronous machine with periodic mechanical component of the alternating depending on the angle of rotation of the rotor. The problem is complicated because the presence of periodic component leads to problems of nonlinear. This procedure allows the direct determination of the Fourier spectra of the most important volumes describing the synchronous machine. Sample calculations were performed for a synchronous motor operating in the state of synchronism and fixed mechanical load torque varying periodicaly at a specifed course.

This paper presents an attempt to detect short circuits in double sourced electrical lines by discrete wavelet transform. First part of this talk describes a database preparation which is created by dynamic simulation base on model of double sourced transmission line. In order to choose the right model a comparison of two different represent of line has been made. In first one, transmission line is represented by two four-poles, and the second one is represented by n-four poles. Steady state’s analyses of different kinds of short-cuts show that two four-poles model line with acceptable precision. Simulation’s results for all kinds of short-cuts create a vast database. The database can be used to project detection algorism based on discrete wavelet transformation.

This paper presents an analysis of short circuit signals by discrete wavelet transform. The signals are obtained by simulation on two four-pole UHV transmission line’s model. Both efficacy of short circuit detection and sensibility to other system’s faults are discussed. An important part of the article is to consider the great influence of well adjusted wavelet function and decomposition level on correctness and speed of short circuit detection. The adequate selection of detection algorism’s parameters based on database including the signal’s samples shows a possibility of practical use of this kind of information in real transmission lines.

Proposed a method of optimizing the number of phases of the parametric transducer using RLC-chain and a genetic algorithm that allows the most approximate shape of the transducer output signal to an ideal three-phase voltage.

Full efficiency of energy conversion in small hydropower plants (SHP) can be achieved for power technology with generators working at a variable speed. This paper presents a concept of a energy conversion system dedicated for application in a prototype SHP which is based on a permanent magnet (PM) generators with a propeller turbine integrated with the generator rotors. These PM generators can work at a variable speed and therefore energy produced by the PM generators have to be converted by means of a power electronic unit to fit to the three-phase power grid parameters. The elements of such SHP like PM generator and power electronic unit are described in details.