All posts by cburada

On the Thermographic Analysis and Thermal Re-sistance Estimation of the Capacitor-Run Single-Phase Induction Motors

8 January 2020Fără categoriecburada

Abstract

The real-time estimations of heating of the elec-tromechanical converters are important for both overheat-ing prevention and overall efficiency optimization during operation. The two-phased induction motors with capacitor-run capacitors onto the auxiliary phase are sensitive to the capacitance variations of the capacitor. In this respect, the optimization of the two-phased induction motors with elec-tronically-switched, capacitor-run, supplied from frequency inverters may be achieved if the elliptical magnetic motion field into the machine is controlled such as the ratio between the maximum and the minimum of its amplitude is reduced to unity. Observations of the heat of the machine’s body and an appropriate thermal model may provide information about the eccentricity of the magnetic motion field in the machine. In this work, the authors investigated the impact of the capacitor-run capacitance onto the characteristics of the thermal field of the machine. In this perspective, the authors implemented a method based on the image analysis techniques that allows estimating: (a) the geometric features of the machine from the boundaries of the thermal field, and (b) the temperature distribution onto the cross-section of the body in correlation with the main components of the ma-chine and (c) the thermal resistance of the machine’s body.

Determining Idle Running and Short-Circuit Operating Characteristics of an Asynchronous Traction Motor

8 January 2020Fără categoriecburada

Abstract

Abstract – It is proposed the possibility to simulate the idle running and short-circuit characteristics of an asynchro-nous traction motor. Based on the results, the motor pa-rameters can be determined. In the modern design of asyn-chronous motors, the simulation of these characteristics is required as a mandatory stage. On this basis, the electro-magnetic stresses and the constructive solutions are finally established, so that the engine corresponds in operation. The tests are important, as they allow for a computation of the motor parameters. There still exists the possibility to simu-late the stationary and dynamic modes, in order to deter-mine the behavior of the motor while running. The compari-sons between the simulated and the data provided in the motor datasheet proves that the occurring errors are under the 2.1 % level accepted as precision level. The correctness of the simulations performed is important in operation, be-cause with the parameters and the results obtained we can anticipate the behavior of the machine in the dynamic or stationary modes. The operating, starting and speed charac-teristics of the asynchronous traction motor must meet the high demands imposed by the complex equipment used in modern transport vehicles. Concerns related to the devel-opment of new methods and procedures to optimize the construction of the asynchronous motors used in traction, to find new mathematical models for the correct simulation of the operating characteristics, are a permanent activity. The simulations and experimental tests were carried out consid-ering a traction motor from a diesel electric locomotive.

Identification and Sensorless Control Using Embedded System of PMSM Based on FOC Strategy and Power Factor Correction

8 January 2020Fără categoriecburada

Abstract

This article presents the procedure for identifying the electrical and mechanical parameters of the PMSM (Permanent Magnet Synchronous Motor). The parameter identification procedure is required in the event that the motor’s electrical and mechanical parameters are unknown, or in industrial applications at the beginning of a drive cycle due to variations of the PMSM parameters with the tem-perature. The parameter identification procedure is imple-mented in the Matlab/Simulink environment. This proce-dure was also implemented in an embedded system and the results of the two (offline and online) identification methods of the nominal parameters of the PMSM are presented comparatively to the parameters in the datasheet. It pre-sents the block structure of the PFC together with the nu-merical simulations achieved in Matlab/Simulink, on the improvement of the PF (Power Factor) of the supply circuit. It also presents the block structures of the FOC (Field Ori-ented Control) strategy and of the back-EMF (back Elec-tromotive Force) sliding mode, MRAS (Model Reference Adaptive System), and PLL (Phase Locked Loop) type ob-servers. The numerical simulations show the superiority of rotor speed estimation when using the back-EMF sliding mode observer compared to the rotor speed estimate pro-vided by MRAS and PLL observers.

Contactless Power Transfer – Theoretical Principles and Fields of Applications

9 January 2019Fără categoriecburada

Abstract

Contactless energy transfer 1 has indubitable advantages in modern technique given by the lack of electro-mechanical contacts predisposed to pitting and failure: use in aggressive or explosive (no sparks) environments, application to mechanisms with translation or rotation move-ments (robotics), high efficiency on relatively short distances a.s.o. Recent researches carried out in Romania demonstrate the feasibility of these systems for a wide power range, from a few watts up to tens of kW, suitable for the expansion of the electro-mobility and proliferation of multimedia and mobile communication devices. Such systems impose storing the energy in batteries requiring frequent charging. The concept of high frequency transformer with separable windings, as well as a capacitor with separable electrodes working in near field regime, the use of resonance and magnetic flux concentrators for increasing the transfer efficiency, some practical achievements and also maintaining of electromagnetic compatibility within well-defined limits are presented. The paper aims to draw the attention of users and also of prospective investors on the applications and advantages of these systems and to encourage national partnerships for developing theoretical and applied research in this field.

Wireless Power Transfer Analysis Using Scattering Parameters

9 January 2019Fără categoriecburada

Abstract

Wireless power transfer systems (WPTS) can be made more efficient from the emitter-receiver and from the active power transfer efficiency point of view by using the scattering parameters S. Using electrical circuit theory and starting from the correct formulation of scattering parame-ters, S parameters are computed in an automated manner based on modified nodal equations corresponding to WPTS. Advanced computation software (ADS, Ansoft Extractor Q3D, Cadence, etc.) is used to compute the parameters cor-responding to the magnetically coupled coils. The magneti-cally coupled coils can be described by the parameters of the resulting equivalent circuit, such as: impedance and admit-tance matrices, transfer coefficients matrix and the scatter-ing parameters matrix. This paper presents on one hand the correct formulation of S parameters and on the other hand the practical use of these parameters to streamline the wire-less energy transfer. To generate the analyzed parameters, dedicated function were developed in MATLAB and exist-ing routines from the Microwave toolbox (MATLAB) have been used. The frequency variation of S has been studied using graphical representation and Smith diagram. The accuracy in defining the scattering parameters S, based on analog circuit theory in harmonic state, in complex domain, is confirmed by the results obtained using the program ADS, that contains routines specific for generating S parameters.

Easy Design Procedure of PCB Inductors Using WEBENCH Coil Designer

9 January 2019Fără categoriecburada

Abstract

This paper describes the use of WEBENCH Coil Designer for generating wireless power transfer PCB induc-tors for low and medium power portable systems without the need of complex calculations or complex layout design. This tool is also used to generate the design files that engi-neers can include in their final designs. These results are of great importance in the wireless charging domain, with ap-plicability from mobile phones to industrial equipment charging. The designed coil inductors can also be used in medical equipment by printing them on flexible materials. To minimize the cost and design time for new products, the use of a specialized tool, like WEBENCH Coil Designer, is recommended for new and experienced engineers. Switching to PCB inductors is more cost effective and creates more stable inductors with precise electrical parameters and good repeatability.

Design of Wireless Electromagnetic Energy Transfer Systems

9 January 2019Fără categoriecburada

Abstract

This paper presents a set of diagrams for wireless power transfer systems (WPTS) with applications in key domains such as: medical, electrical engineering, military, etc. Our research is based on original circuits working as WPTS. All the circuits are using sets of two magnetically coupled coils whose parameters were extracted by simula-tions using the specialized software ANSOFT Q3D Extrac-tor. The simulations of the circuits were performed using TINA, PSpice and Simulink in MATLAB. We used existing parts libraries from Texas Instruments. The circuits were also physically built and tested and the results were very close to the numerical ones. We also compared the results with data in existing literature and we obtained an accept-able computation error. We also studied the efficiency of the power transfer and presented some practical applications for these systems such as low power battery chargers.

An Analysis on Efficiency of Wireless Transfer Energy Due to a Misalignment of Two Coils

9 January 2019Fără categoriecburada

Abstract

Function of the alignment of the two magnetic coupled coils, a procedure, to choose the proper structure of the two coils used in the wireless power transfer systems (WPTS’s), is presented. The deviation in the alignment of coils can be made in two ways – the angular displacement and the lateral displacement. For the lateral displacement, the two coils are located in parallel planes with their centres misaligned, respectively in the case of angular displacement there is an angular deviation between the receiver and transmitter coils having aligned centres. The main target is to compare the obtained results and select the best solution with the great value for mutual inductance. The main focus was on the influence of lateral displacement of two coils, for two configurations: transmitter and receiver coils are circu-lar type; transmitter coil is pancake type and receiver coil is circular type. After the simulations, we shown that there is a smaller deviation from initial value of the mutual induc-tance for the second case (transmitter coil is pancake type and receiver coil is circular type). Combining the two effects (angular and offset side) we get a surface where if the re-ceiving coil is located on it, the coupling factor of the wire-less system has the same value

Modeling, Simulation and Practical Realization of the Spiral Inductors Used in Wireless Power Systems

9 January 2019Fără categoriecburada

Abstract

With the increase of the number of devices pow-ered and using wireless systems, the optimal design of such systems is necessary. The present study aims at determining the influence of parameters like distance between inductors and the placement of ferrite layers on the phenomena re-garding the spiral inductors through their numerical model-ling. A simple wireless power system constructed from an emitter and a receiver spiral inductor is considered in the present study. The numerical modelling of the system is made using the software program Ansys Maxwell 3D Field Simulator. Also, a comparison of the results obtained from the modelling and simulation of this wireless power system and from a practical model made in the laboratory is pre-sented. As the modelled structure, the practical model is constructed from two spiral inductors. The importance of numerical modelling of the structure in order to determine an optimum is highlighted. The parameters obtained and analysed from the 3D model are magnetic field intensity, magnetic induction and mutual inductance, while for the constructed model the voltage is studied. For the modelled structure, the distance between the receiver and the emitter is varied between 0.05 mm and 5 mm, considering the struc-tures with and without the ferrite layers in order to reach a conclusion.

Inductive Power Charging for Electric Vehicles in Misalignment Conditions

9 January 2019Fără categoriecburada

Abstract

This research work deals with the challenges and issues facing the misalignment contactless inductive power charging of electric vehicles (EVs). The focus is on analysis and design of the inductive power transfer (IPT) for dynamic (in-motion) charging systems. The computational electromagnetics approach is used here, and a graphical and programming platform is developed capable to link and co-simulate the models of the coupled coils with the models of the external circuitry of the overall IPT system consisting of: high frequency power inverter on the primary coil side, resonant tuning capacitors, diode bridge rectifier on the secondary coil side, DC filtering capacitor and the vehicle battery load.