Model of pulsating current traction motor taking into consideration magnetic losses in steel

The aim of the work is to develop a mathematical model of the traction motor of the pulsating current of an electric locomotive taking into account the magnetic losses in the motor steel to determine the starting parameters depending on the voltage of the armature winding. Methodology. Mathematical modeling of electromagnetic processes in a traction motor of pulsating current is applied taking into account the nonlinear nature of the armature inductance, the inductance of the excitation winding and the nonlinear nature of the universal magnetic characteristic. The magnetic losses in the steel of the traction motor were taken into account by establishing the dependence of these losses on the frequency of reversal, the magnetic flux in the magnetic circuit of the motor and the geometric dimensions of the motor. Results. The mathematical model of calculation of starting parameters of the traction engine of the pulsating current of the traction drive of the electric locomotive of alternating current taking into account the equation of instantaneous value of losses in engine steel is developed. The dynamic characteristics of the traction motor with pulsating current are obtained. It allows to investigate starting parameters of the traction engine on the basis of the received mathematical model and to design elements of the traction drive of the electric locomotive according to the specification, to choose optimum design parameters. Originality. For the first time a comprehensive study of the pulsating current traction motor was carried out taking into account the nonlinear nature of the armature inductance, excitation winding inductance and nonlinear nature of the universal magnetic characteristic and taking into account the magnetic losses in the motor steel. Practical significance. The model of the traction motor of pulsating current taking into account losses in steel of the engine on the basis of the carried-out calculation is developed. Experimental studies have confirmed the adequacy of the model, which allows to apply the obtained model to develop a mathematical model of an AC electric locomotive to study the electrodynamic processes in it at different modes of operation of the electric locomotive.Запропоновано підхід до імітаційного моделювання тягових електродвигунів пульсуючого струму, заснований на врахуванні нелінійного характеру магнітної характеристики, індуктивностей якоря та обмотки збудження. Розроблено модель магнітних втрат у магнітопроводі якоря електродвигуна та досліджено їх вплив на характер електромагнітних процесів у електродвигуні. Показано, що отримані при цьому рішення узгоджуються з отриманими раніше результатами, але відкриваються додаткові можливості при дослідженні роботи двигуна в складі тягового електроприводу електровозу однофазно-постійного струму

Improvement of the Model of Power Losses in the Pulsed Current Traction Motor in an Electric Locomotive

When studying transients in pulsed current traction motors, it is important to take into consideration the eddy and hysteresis losses in engine steel. Magnetic losses are a function of the magnetization reversal frequency, which, in turn, is a function of the engine shaft rotation frequency. In other words, magnetic losses are a function of time. Existing calculation procedures do not make it possible to derive the instantaneous values of magnetic losses as they are based on determining average losses over a period.This paper proposes an improved model of magnetic losses in the steel of a pulsed current traction motor as a function of time, based on the equations of specific losses.The adequacy criteria of the procedure for determining magnetic losses in electrical steel have been substantiated: the possibility to derive instantaneous values of magnetic losses in the magnetic material as a function of time; the possibility of its application for any magnetic material; and the simplicity of implementation. The procedure for determining magnetic losses in the steel of a pulsed current traction motor has been adapted by taking into consideration the magnetic properties of steel and the geometry of the engine's magnetic circuit. In order to determine the coercive force, the coefficient of accounting for the losses due to eddy currents, as well as the coefficient that considers the losses on hysteresis, the specifications' characteristics of specific losses in steel have been approximated using the pulsed current traction motor as an example. The simulated model of magnetic losses by the pulsed current traction motor has demonstrated the procedure for determining average magnetic losses and time diagrams of magnetic losses.The proposed model for determining magnetic losses could be used for any magnetic material and any engine geometry under the condition of known material properties and the characteristics of change in the magnetic flux density in geometr

Determination of Voltage at the Rectifier Installation of the Electric Locomotive VL-80K for Each Position of the Controller Driver's

The object of research is the electrical processes in the control system of the traction drive of the electric locomotive VL-80K (Russia). To improve the accuracy of its mathematical model, it is necessary to use the values of the parameters determined during experimental studies of the traction drive control system. In particular, it is important to use in the traction drive model the value of the voltages on the arms of the rectifier installation of the electric locomotive, taking into account the position of the driver's controller. The complexity of the simulation lies in the fact that the reference does not provide the value of the voltage on the arms of the rectifier for each position of the driver's controller, which makes it difficult to verify the resulting model. A scheme for measuring the voltage value on the arms of the rectifier installation of an electric locomotive for each position of the position of the driver's controller is proposed. On its basis, a simulation model is developed in the MATLAB software environment. The simulation model implements an algorithm for closing the contactors of the electric group contactor for each position of the position of the driver's controller. Approbation of the voltage measurement technique was carried out on an electric locomotive of the VL-80K series during a trip on the Darnytsia-Myronivka section (Ukraine). Comparison of the voltage values on the arms of the rectifier installation, obtained experimentally, with the passport data showed that the measurement error was 0.5 %. In addition, the experimental results showed that the voltages on the arms of the rectifier for paired positions of the position of the driver's controller are the same, for odd ones they are different. Therefore, when simulating the operation of the traction drive control system, the voltage values on different arms of the rectifier installation were taken separately. Comparison of the simulation results for the nominal mode with passport data showed that for this mode the measurement error was 3.78 %. For all others, it did not exceed 5 %

Mathematical Modeling of an Induction Motor for Vehicles

It has been proposed, in order to model an induction motor for vehicles, to employ a system of differential equations recorded in the «inhibited coordinates». To improve the algorithm robustness, the number of the system's equations was reduced by expressing the phase currents through the phase flux linkage. The parameters of the prototype engine have been defined in line with the classical procedure. An algorithm has been constructed in order to account for the mechanical losses and power losses in the engine steel. An induction motor with symmetrical windings has been simulated in the MATLAB programming environment. The basic technical parameters for the engine were determined using the simulation model. The simulation results have been compared with the results of classic calculations. The error in determining the parameters based on the model and those calculated did not exceed 7 %. This indicates a high convergence between the simulation results and the results of calculations. It has been proposed, in order to study an induction motor with the asymmetrical stator windings, to apply the algorithm that implies accounting for a change in the mutual inductance at a change in the integrated resistance in the single or several phases of engine windings. The proposed algorithm for managing the asymmetric regime of stator windings could make it possible, without changing the structure of the model, to investigate the dynamic processes in an induction motor in case of the asymmetry of stator windings phases when they are damaged. Taking into consideration the losses of power in steel, as well as the mechanical losses, would improve the reliability of the results obtained. The error of determining the parameters of an induction motor at asymmetrical stator windings, obtained at modeling, and acquired experimentally, did not exceed 3 %, which testifies to the adequacy of the model.That would make it possible to apply the proposed simulation model of an induction motor when studying the dynamic processes in the engines used in the transportation infrastructure, in case of such a defect as the interturn short circuit in the stator winding