Vector Control and Modeling of Modular Multilevel High Voltage Converter for Rail Vehicle Traction

Rail transit plays an important role in the social and economic life of China and even all countries in the world, especially some populous countries or regions. The traction drive system of rail vehicle provides three-phase AC with adjustable voltage and frequency for the traction motor, controls the speed and torque of the traction motor, and then controls the operation of the vehicle. The modular multilevel converter has the advantages of low harmonic, good power quality of output waveform, high reliability, no input filtering and power compensation, and is suitable in the field of frequency conversion. In this work, the open-loop scalar control and vector closed-loop control of modular multi-level high-voltage inverter were adopted. It was found that driven by modular multi-level variable frequency vector control system, asynchronous motor not only has less harmonic content of voltage and current waveform, but also its speed regulation characteristics have been improved.

Modelling of the shape of railway transition curves from the point of view of passenger comfort

In the past, railway transition curves were not used. Instead of it, a simple connection of the straight track and circular arc was applied. Nowadays, such simplicity is not allowed due to the increasing vehicle operating velocities. It is mainly visible in the high-speed train lines, where long curves are used. The article aims to develop a new shape of railway transition curves for which passenger travel comfort will be as high as possible. Considerations in this paper concern the polynomials of 9th- and 11th-degrees, which were adopted to the mathematical model of the mentioned shape of curves. The study's authors applied a 2-axle rail vehicle model combined with mathematically understood optimisation methods. The advanced vehicle model can better assign the dynamical properties of railway transition curves to freight and passenger vehicles. The mentioned model was adopted to simulate rail vehicle movement in both cases of the shape of transition curves and the shape of circular arc (for comparison of the results). Passenger comfort, described by European Standard EN 12299, was used as the assessment criterion. The work showed that the method using the 2-axle railway vehicle model combined with mathematically understood optimisation works correctly, and the optimisation of the transition curve shape is possible. The current study showed that the 3rd-degree parabola (the shape of the curve traditionally used in railway engineering) is not always the optimum shape. In many cases (especially for the long curves), the optimum shape of curves is between the standard transition curves and the linear curvature of the 3rd-degree parabola. The new shapes of the railway transition curves obtained when the passenger comfort is taken into account result in new railway transition curves shapes. In the authors' opinion, the results presented in the current work are a novelty in optimisation and the properties assessment of railway transition curves.

Modern combustion-electric PowerPack drive system design solutions for a hybrid two-unit rail vehicle

The article presents an innovative solution of a two-unit rail vehicle system for passanger transport with a dual-drive, diesel engine and electric motor. The vehicle was designed as a combination of two units, one dedicated to each of the two drive systems, where one unit provides electric drive while the other a combustion engine. The selection of engine and drive components was presented along with the aftertreatment systems used in the design. The provided solution was created in response to the dynamic needs of rail vehicle operators in the European Union who aim to reduce exhaust emissions without compomising the reach of the existing rail networks.

Passive safety features of a type 227M rail vehicle

Bezpieczeństwo pasażerów w transporcie szynowym jest jednym z najważniejszych aspektów konstrukcji pojazdów szynowych. Utrzymanie niskich statystyk śmiertelności tej gałęzi transportu wymaga rozwoju systemów transportowych, ale także dalszego rozwoju materiałów i systemów stosowanych w konstrukcji pojazdów, które poruszają się po torach Polski i Świata. W niniejszym artykule przedstawione zostały zagadnienia bezpieczeństwa pasywnego na podstawie konstrukcji lekkiego pojazdu szynowego typu 227M.

Materials used in the construction of rail vehicle wheels

Przedmiotem niniejszego tekstu jest opis materiałów konstrukcyjnych stosowanych w budowie kół pojazdów szynowych. Przedstawiono charakterystykę tego elementu konstrukcyjnego, a także jego wymagania funkcjonalne oraz materiałowe. W dalszej części zaprezentowano opis powszechnie używanych stali węglowych oraz alternatywnych materiałów konstrukcyjnych, takich jak staliwa, żeliwa ADI czy stopy aluminium, które w założeniu miałyby ograniczać zużywanie pary ciernej koło-szyna oraz zmniejszać poziom emitowanego hałasu.

The construction of suspended rail vehicle bogie

Niniejsza publikacja została poświęcona szczegółowemu opisowi wózka, przeznaczonego do wykorzystania w proponowanej przez autorów koncepcji podwieszanego pojazdu szynowego. W pierwszej kolejności skrótowo opisano rzeczony pojazd, ze szczególnym naciskiem na parametry determinujące konstrukcję wózków. Następnie zostały omówione zastosowane rozwiązania konstrukcyjne w zakresie budowy poszczególnych podzespołów wózka, takich jak: zestawy kołowe, rama, dwustopniowe usprężynowanie, układ napędowy i hamulcowy. Artykuł ten powstał na podstawie pracy dyplomowej pt. „Koncepcja wagonu silnikowego kolei podwieszanej”, na wydziale Mechanicznym Politechniki Gdańskiej.

Parametric Analysis of the Ride Comfort of Indian Railway Vehicle

This paper focuses to the parametric analysis of Indian Railway Rajdhani (LHB) coach. A suitable mathematical model of 40 degrees of freedom (DOF) is formulated by Lagrangian method. The mathematical model of rail-vehicle is modelled by considering eleven mass system containing of backseat support (without cushion), a seat, a car body, two (front and Rear) bolsters, two (front and Rear) bogie frame and four wheelaxles (front bogie front and rear wheel axles and rear bogie front and rear wheel axles. The vehicle is simulated to travel at speed of 100 km/hr on a tangent track. The results from the simulation are validated by comparing the same with the results from experimental data which is acquired from research designs and standards organization (RDSO), Lucknow (India). The parametric analysis is performed to estimate the effect of different parameters of rail-vehicle on the ride behaviour.

Investigation Forecasting Methods of Noise Level From Rail Trams in Lviv City

The method of localization of noise level calculation from a rail vehicle in the city of Lviv is investigated and developed. Models of noise load measurement have been adapted, the measured values have been unified and our own solution has been created on the basis of the road surface, the speed of rail transport and the distance from the noise source. According to the research methods, namely: Schall 03 (from Germany), Nordic Train (Scandinavian countries) was carried out compared to the Bland—Altmann schedule, with which we can adapt the studied results. distance from the noise source. As a result, models for predicting noise load measurements were adapted. The results were carried out compared to the Bland-Altmann plot, which helped us with the comparison table. The purpose of the study is to analyze methods for noise level measurements and adapt them into our realities. Based on the known methods of measuring the noise load of railway vehicles, we can assume that there are no correct methods for the cities of Ukraine (especially Lviv).