The article shows a new field of application for the matrix converter (MC) as the interconnecting device between the high speed, permanent magnet generator and the grid. The converter works under the developed control algorithm based on a so called ‘area based’ approach. The device consists of a converter, a transformer (or transformers) and filters and is supposed to substitute or revolution decreasing gear box or DC link based power electronic converter. Several structures, including multiphase structures (3, 12 phase) were investigated and their properties were assessed using the results of Matlab Simulink based simulations. The simulations were performed using the standard Simulink models and the developed, simplified permanent magnet motor model. The results were very satisfactory, i.e. input waveforms distortions, output current and machine torque ripples were at acceptable levels for the multiphase structures and high frequency input. The waveform distortions were found to be a function of input frequency and the number of phases in the conversion device, but the structure of the converter was limited to a 12x12 structure for economic reasons.

An analysis of the energy conversion system which consists of a propeller water turbine, a permanent magnet synchronous generator and a power electronic converter is presented. The considered control strategy implements an optimizing technique that guarantees maximal average efficiency independently of hydrological condition changes through the constant search for optimal operation parameters. The water flow parameter, essential for objective function estimation, is eliminated by the dedicated control technique. The control method is implemented and tested in the model created in the Matlab/Simulink software. All characteristics and parameters were identified on a real small hydropower plant and on the special laboratory model.

This paper presents the design, simulation and measurement of a synchronous motor prototype with an external rotor using permanent magnets. The motor was optimized for high-torque, in-wheel operation. Based on geometric dimensions, a 3D solid model was created. The electromagnetic design was calculated in ANSYS/RMxprt. A cross-section with graphical presentation of magnetic induction in particular parts of the electromagnetic circuits and the simulated and measured characteristics of the motor are shown.

This article presents the results of modeling the phenomenon of free and forced magnetization in three-phase, three-legged transformers. The no-load state of the transformer has been modeled using the program including a circuit model of the transformer. The results obtained have been compared with measurements carried out in the laboratory for the various circuits connection of the transformer.

The study of the interaction between faults of different natures is a crucial step for the development of effective systems for fault detection. The analysis of the electrical signals using the actual motor current signature analysis (MCSA) techniques may lead to different results and, as a consequence, an incorrect diagnosis of the fault due to the fact that the non-linear interactions between both faults are difficult to predict with high precision. The relationship between the electrical and mechanical components has been extensively studied in the past, but despite the progress made, the introduction of new control systems or the nonlinearities presented in the electrical machine, still makes it hard to diagnose faults. The study below attempts to show the evolution of the induction motor signatures when electrical and mechanical faults occur simultaneously. The Fourier analysis of the signatures presented in this paper indicates that the typical analysis carried out to diagnose the state of the electrical machine may be interpreted as an indicator of a different type of fault.

This paper takes into consideration two PMSM motors of size 80 with very similar efficiency and output power. In the article, design differences between a classic 4 pole/24 tooth motor with distributed winding and a 10 pole/12 tooth motor with concentrated winding are shown. Calculations and tests results are also presented for both machines.

The purpose of this paper is to present some selected issues relating to the alternative application of the perspective concept on the plane board MEA (More Electric Aircraft), instead of the traditional solution, in terms of power (pneumatic and hydraulic systems). In the context of the analysis of this trend, particular attention is paid to the major advantages that aeroplanes have, made in accordance with the new technology and problems in autonomous systems of electricity generation (electric power grid of aircraft). Considering that the largest growth of the above trend of electric aircraft (MEA) applies to civil aviation, the most important role in this paper was assigned to civilian aircraft (Boeing, Airbus) in the context of power distribution in electro-energy systems. In addition, a review of air sources of electricity (electric power) generation was made for particular types of energy sources (generators, generator-starters, transformers, converters, etc.) and advanced on-board autonomous power systems ASE (Autonomous Electric Power Systems), used in most modern aircraft constructions (passenger and military aircraft). In the final part of this paper, based on a literature review of electric aircraft concepts (MEA) and a brief analysis, the main conclusions arising from the application of this trend in modern aviation are presented.

This paper presents an analysis of the influence of utilizing rotor materials of different magnetization and conductivity on steady-state torque-speed characteristics for a high-speed eddy-current brake. The analysis involves rotors of different active lengths, with or without axial slits and a copper layer on the surface. The calculations were carried out using two and three-dimensional numerical models, partially verified on the laboratory test-stand.

Continuous development of technology determines the search for new solutions in the field of electric machine design with improved electromechanical properties. In recent years, there has been an increased interest in passive and active magnetic gears. This paper presents the design, operation and performance analysis of the modified magnetic gear. The new prototype magnetic gear allows obtaining a ratio of 4:1 or 5:1. For the analyzed construction, two and three-dimensional numerical models are developed for which the series of the magnetic field calculations are carried out . The characteristics of the magnetic torque vs. angle position of the inner rotor with respect to the intermediate ring (modulation ring) and the outer rotor are determined and compared. The examples of flux density distributions for the analyzed converter construction are presented. The calculation results are verified with measurements on the prototype.

shortening of the life of the machine due to the phenomenon of the thermal ageing of insulation. Therefore, it is extremely important to know the exact temperature distribution in different parts of the electrical machine under various operating conditions. This paper presents a lumped parameter thermal model and FE model of a permanent magnet synchronous motor. A method for the homogenization of a stator winding is also described. In order to validate the accuracy of the calculation results, measurements on the physical model of the machine were carried out.

Two-phase switched reluctance motors are distinguished by their very simple design and belong to the group of high-speed motors. At high rotational speeds, losses in the core of a 4/2-pole switched reluctance machine are much lower than those occurring in a SRM with a larger number of phases. Unfortunately, a flaw of such a solution consists of a difficulty to obtain the starting torque in certain rotor positions. This occurs in the case of a symmetrical stator and rotor layout. To obtain the starting torque in any rotor position, an asymmetric design of rotor has been employed. In the framework of this study, a simulation model of such a machine was developed with the use of which motor characteristics were obtained for two specific working points, namely for very low and very high rotor speeds. Special attention was also focused on the problem of voltage control at high rotor speeds. On the grounds of the obtained results, an analysis of properties of the examined drive was performed from the point of view of the development of a practical control circuit for a two-phase SRM.

This paper presents a methodology of error analysis in a mathematical model of an electromechanical actuator using Hamiltonian equations in the description of energy conversion. As the basic quantity in numerical algorithms, the coenergy of magnetic field Ecm is employed. The reason for the application of coenergy as a state function is the explicitness of its value for a given set of state variables, resulting from neglecting eddy currents and hysteresis phenomenon in the model.

The design and development of an axial-flux ferrite magnet slotless generator for use in a small-scale wind turbine is described. The 4/4-pole single-phase machine is designed for simplicity and ease of manufacture and it consists of one slotless stator disc. The generator produces approx. 12 W at 1000 rpm with electrical efficiency of up to 46%. Because the efficiency of the machine is important, the power curve characteristics and voltage produced by the generator are investigated. The presented generator should generate sufficient output DC voltage to charge 4 to 5 batteries of 12 volt each. Finally, the finite element (FE) results are compared with measurements on a prototype. The calculated values coincide to a strong degree with the experimental results.

In this paper, the series configuration of pole winding connections in each phase of a three-phase 12/8 switched reluctance motor was analyzed. Based on the simulation model, the effect of magnetic couplings on motor properties was determined. Static characteristics were obtained for NNSS and NSNS configurations. Voltage, current, and electromagnetic torque waveforms were determined. Simulation results were verified through laboratory tests.

A hybrid drive of an unmanned aerial vehicle uses two mechanically coupled drives. In one of the drives, an electrical machine is used. Its role is not only limited to a motoring operation, e.g. during achieving the flight ceiling. The electric machine changes its operation into generating after reaching the flight ceiling, this allows not only meeting current electrical energy demands but also battery recharging. This paper presents the results of laboratory tests of a BLDC machine in motoring and generating operation. Mechanical characteristics of the motor for different supply voltages and external characteristics for generator were determined. The possible energy conversion efficiencies for both motoring and generating operations were determined.

Two-phase permanent magnet synchronous motors are discussed in this paper and the influence of the magnet sizes on cogging torque (CT) is explored. The cogging torque has been calculated using ANSYS/Maxwell software. In more detail, influences of the magnet size, their positioning and orientation to the CT in two basic rotor types were studied. The cogging torque waveform for critical dimensions has been considered using the FFT analysis. The first rotor type is with semi-arc shaped magnets located on the rotor surface. The second motor type features magnets embedded in its rotor. The shape of the stator magnetic circuit has been predetermined.

A two-dimensional, field-circuit model of a 55.5 MVA hydrogenerator is presented in the paper. This model takes into account the fractional-pitch stator winding, the rotor damper squirrelcage, nonlinear magnetization curves and the rotor motion. Verification of the model has been carried out by the comparison of the no-load and short-circuit characteristics computed using the finite element method with those obtained from measurements.

The article presents the results of the impact of various geometric dimensions of torque in a complex motion electromechanical converter. The converter differs from the conventional radial structure motor in that it has two rotors, an inner and an outer, and excitation by a common stator which is located between them. The use of such a system introduces different size ratios relative to the normal external rotor motor. The result is that the shape of the torque curve of the outer rotor is different from the one in the internal rotor. This article presents a study on the impact of individual items in the course of time – this relied upon a comparison of several hundred configuration dimensions.

This paper presents possibilities for reducing the costs of electricity generation as a result of modernizations aimed at increasing the rated power of turbogenerators. Programs for calculating temperature fields in large AC machines have aided work on turbogenerator modernization. Turbogenerators with increased rated power operate in many power plants in Poland and abroad, e.g. in Bulgaria, Finland, Greece, Slovenia, Korea and China. The example of TWW‑200‑2(2A) turbogenerator modernization is presented. The improved fans with increased capacity have enabled the increase in the turbogenerator rated power by 20%.

In this paper, the steady-states operation of a line start permanent magnet synchronous motor (LSPMSM) and a squirrel-cage motor have been compared. The stator of a Sg 100L-4B type, 3 kW induction motor, was used in both structures. The squirrel cage in the rotor of the LSPMSM is made from copper. The influence of the frequency change of the supply voltage on the motor’s efficiency and current as well as the power factor has been examined.

This paper is devoted to a new piezoelectric bending resonant transducer prototype dedicated to the characterization of the mechanical properties of soft tissue. A general description of the actuator’s structure is presented including the basic principles of the measurement. The chosen geometry of the prototype is discussed and compared with the existing version. Constitutive equations are presented for the active and passive layer of the cantilever transducer. The prototype is verified by means of finite element method analysis. Results of the static and modal analysis are presented and discussed.

This article presents a variable-speed converter system for wind energy conversion. The considered system consists of a wind turbine with a permanent magnet synchronous generator (PMSG), a machine-side converter, a grid-side converter and control circuits. Mathematical models of the components of the wind energy system are described. The control algorithms of the converter systems based on the vector methods of control are also described. The considered wind energy system were studied by digital simulation. The simulation results are presented and discussed.

This paper presents research issues of electric generators using systems of the Hardware-in-the-Loop (HIL) type. Using the HIL system, it is possible to reproduce the actual operating conditions of wind turbines working with different types of generators in a laboratory environment.m This approach easily and economically allows analyzing the hardware and software controlling the operation of the generator. This system has been implemented on the sbRIO National Instruments controller cooperating with regenerative frequency converter with DTC control of ABB. The paper presents all the components of this system and discusses their operation.

Electrical drives become more and more interesting for many applications in mobile machines including farming equipment. In this paper, the electromagnetic design of a threshing cylin der for an electrical combine harvester with a function-fitted external rotor and an inner stator is shown. Special attention will be paid to the calculation of the eddy current losses within the magnets through different FEM methods. The influence on the losses of segmentation of magnets in tangential and axial directions is shown.

This paper presents a method for the continuous technical diagnostic of the core suspensions at selected measurement points of the turbogenerator stator. The method extends diagnostic capabilities of a turbogenerator vibration monitoring system which has been designed with the participation of the authors of this paper and applied within the Polish power industry. This method uses two indicators (suppression and vibration harmonic contribution in suspension nodes) whose values are calculated from acquired and processed data in a given turbogenerator operation period. There has been four value ranges proposed for the indicators. The ranges define a technical condition of a stator suspension (very good, good, acceptable, bad) including two alarm ranges. Each technical condition is presented as a colourful area on an idle and active power plot. This enables the quick identification of machine operation areas, which reveals the weakened technical condition of a stator component.

The paper presents a two-dimensional field-circuit model of a two-winding, single-phase induction machine operating as single-phase, self-excited induction generator. The model takes remnant magnetism and magnetization characteristics of the stator and rotor core into account. Results of simulations and experiments are presented, i.e. waveforms of voltages during self-excitation, their dependence on rotor slot opening, influence of capacitances and different capacitor topologies on self-excitation, as well steady-state values of generator voltages and currents at no-load operating conditions. Terminal voltage and currents in stator windings as a function of rotor speed and capacitances of capacitors for resistive loads are also presented. The possibility of directly supplying a single-phase induction motor from the generator as a dynamic load were also investigated. Obtained simulation and experimental results show the need for use of semi-closed rotor slots to ensure conditions for successful self-excitation. The obtained simulation results were validated experimentally on the laboratory setup.

This paper presents an analysis of the synchronization process of the high-power, two-speed synchronous motor out of over synchronous speed. A method of increasing the effectiveness of synchronization by applying a change system of polarization of the field circuit supply DC voltage is proposed. The process of synchronization from the stator supply voltage is also analyzed. The influence of the periodic reduction value of the supply voltages on the synchronization processes was also investigated. The proposed synchronization method can be applied during the synchronization processes of line start permanent magnet synchronous motors with a two-stage start-up.

This article presents the results of a study on the magnetic properties of soft magnetic powder composites at room temperature and at liquid nitrogen temperature. The properties of a magnetoelectric motor with the power of 0.75 kW at room temperature and cryogenic temperatures are also presented in this article. The study of magnetic properties showed that magnetization curves at 20°C and -195.8°C temperatures are almost the same. Iron loss in the composite at liquid nitrogen temperature increased significantly in comparison to loss at room temperature. The study of the magnetoelectric motor showed that the back electromotive force at liquid nitrogen temperature decreases insignificantly in comparison to the back electromotive force at room temperature. Electromagnetic torque at liquid nitrogen temperature increases in comparison to room temperature.

In typical dynamo steel sheets, the magnetization process can have a two-fold character. In parts of the dynamo sheets which refer to the stator core of induction motors the magnetization process has a rotational character. On the other hand, the axial magnetization occurs mainly in the stator teeth. This paper discusses the specific power loss of typical dynamo sheets and its dependence on the magnetization frequency and on the maximum value of the flux density in dynamo sheets. Anisotropic properties of these sheets were taken into consideration. Special attention was given to understanding the dependency of the magnetization direction on specific power loss. The measured specific power losses of two selected dynamo sheets were compared with results obtained on the basis of analytical formulas.

This article deals with the methodological aspects of the modelling and field analysis of machines with surface mounted permanent magnets on the rotor, taking into account the anisotropic properties of the stator core. These considerations are intended to show the effect of anisotropy on the structure of the mathematical model of the machine and answer the question of whether if based on classical modelling, it is possible to take into account the rotational magnetization phenomena. The results explain the question, how the magnetic anisotropy effect at rotational magnetization is important from an exploitation point of view.

This paper compares the accuracy of the multi-frequency stator phase current spectrum estimation. This is as a development of considerations made in [1]. In this paper, the authors added to previous results for the classic Discrete Fourier Transform method and the two-point interpolated DFT method (IpDFT ), new results obtained by three-point IpDFT method’s algorithm. The analysis was made for slip spectrum component which is used for cage damage detection. To minimize the spectrum leakage effect, the selected Rife-Vincent Class I windows (RVCI ) were used. The article focuses on the effectiveness of spectral component estimation in function of the used method, type of time window and measurement time. Values of errors of frequency and amplitude estimations are presented on graphs. The authors compared theoretical considerations with the case of real stator current of an asynchronous motor with a broken cage. This article can be used as a base for further studies on the diagnosis of induction motors.

This paper concerns a circuital model of a 5.5 kVA salient pole synchronous generator with damping bars, with and without the rotor skew. The paper presents an influence of the stator to rotor self and mutual inductance distribution on the induced voltages in the no-load steady state. Inductance distributions used in the circuital model are determined in the FE MM program for linear and nonlinear magnetic circuit. Simulation and experimental verification are presented.

This paper discusses the detection of internal faults in the stator and rotor windings of synchronous machines. Using current signature analysis, it is demonstrated how by using low cost equipment, it is possible to detect the fault by monitoring the currents. The process of detection is totally optimized, and the processing time is enough to identify the fault before the total machine damage. Using the spectrum of the healthy machine as a reference, the followed methodology allows the timely and reliable detection of faults.

The work presented in this paper relates to an Interior Permanent Magnet Synchronous Motor (IPMSM) experimental results and optimization procedure programed in Matlab and Maxwell environments. The stator of the machine is a conventional stator with distributed winding. The subject of the first optimization stage was the geometry of the IPM machine, concerning average torque value maximization and maximum cogging torque value minimization under physical and technological constraints. The optimized rotor core is made of from Magnetic Powder (SMC). It was tested in a generator regime.

The steady state response of a synchronous machine to the torque with angle dependent pulsating component is of great practical importance for the piston drive. Determining such a response is not easy due to the necessity of solving the system of nonlinear differential equations. This paper describes an algorithm that allows directly determining the steady states of a synchronous machine driven by an internal combustion engine (e.g. diesel engine). To create such an algorithm, the harmonic balance method and the iterative Newton–Raphson procedure are used. This approach allows obtaining steady-state solutions directly in the frequency domain. Exemplary calculations are performed for synchronous generators derived from the four-stroke internal combustion engine.

This paper presents thermal calculations and tests of a linear induction motor for a model of a personal rapid transit vehicle drive. Various air and liquid cooling systems are analyzed. Laboratory test results of selected solutions are presented. The thermal equivalent circuit model of selected solutions were made. The calculation results were compared with the test results and the most effective solution was selected.

The work concentrates on the thermal calculations and tests of the permanent magnet machine with an external rotor and cooled with liquid flowing around the inner surface of the stator frame. The distribution of the temperature in the cross-section of the machine, obtained as a result of the thermal net solutions in a steady state is presented. The calculation results are compared with the test results.

Induction motors with some degrees of freedom (more than one) belong to unconventional drives which offer wider possibilities of motion than traditional drives. These motors constitute a small group of electric drives, however, new requirements for mechatronic devices are the cause of growing interest in their steady and regular development. As far as rotary-linear motors are concerned, they can be used in devices dedicated to mixing and drilling ensuring both rotary and linear movements. Because of the complex construction of such motors, their manufacturing process is expensive. In order to reduce these costs, the authors develop and propose the concept of the 3-phase rotary-linear machine built-up on the basis of a standard 3-phase squirrel-cage motor. This approach results in the significant reduction of manufacturing costs through the use of prefabricated parts (e.g. complete stator, stack of stator sheets, motor housing), as well as allowing the partial adoption of technologies used for standard induction motors.

A new design of a brushless direct current motor is introduced in this paper. In the BLDC motor, a high-pressure vane pump is built into the rotor. The motor is excited by neodymium magnets. Its nominal power is 2.5 kW. The motor is built in such a way that the magnetic field does not penetrate the pump. A magnetic structure field analysis of the motor was performed. Demagnetization resistance of the magnets was determined. By the use of time stepping, finite element method waveforms of the electrical and mechanical parameters in the BLDC motor–inverter system were determined.

This paper deals with the results of experimental investigation into a six-pole single-phase line start permanent magnet synchronous motor. The influence of the running capacitor capacitance on the motor running properties was investigated. The influence of the starting capacitor capacitance and its switch-off time on the motor starting properties was investigated.

An equivalent circuit of the insulation system in power transformers comes in many forms. In tests for the dielectric loss tangent (tgδ) of the main insulation, the equivalent circuit has been simplified to two-terminal RC series connected or parallel connected circuits. For direct current tests of groundwall insulation modelling, two two-terminals circuits are required – one for charging and shorting, the other for the voltage recovering after shorting. The model turn-to-turn insulation may also be presented by two-terminal circuits. The parameters of the two-terminal circuit can be determined by direct current. The tested winding is energized by DC voltage, the current is interrupted and the voltage waveform on the terminals of the winding is recorded. The parameters of turn-to-turn insulation (equivalent circuit parameters) are calculated from the voltage waveform and they can be used for diagnostic purposes.