Current sampling techniques and predictive algorithms used in the digital control of electric drives rely on a simple mathematical model that assumes linear current changes upon constant supplying voltages. This paper identifies rotor movement as a factor that makes this assumption invalid when the rotor covers an angular distance of a few tens of degrees during the control interval duration. The errors of the linear current approximation were quantified both by simulation and by experiment for an exemplary high speed permanent magnet synchronous motor drive.

Construction and technical condition of current collectors is crucial to reliability and safety of railway transportation. According to the Technical Specifications for Interoperability railway vehicles in the European Union should be equipped with carbon contact strips. Excessive wear or defects of contact strips degrade the capability of undisturbed power transmission, cause faster wear of contact wire, and can even result in catenary rupture. The technical condition of contact strips is assessed manually during periodical services performed by rolling stock operators. However, rail infrastructure companies are also interested in pantographs inspection of the vehicles running within their network. A novel inspection system for current collectors contact strips is presented. The system uses a specialized camera and a laser line generator to scan the contact strips surface. The scanning is performed on a railway line, when a vehicle passes the inspection point. A prototype of the system was tested in the target conditions and sample scanning results were recorded. Basic algorithms for automatic analysis of contact strips wear were introduced. Accuracy and repeatability of the measurement were assessed. The potential of commercial implementation of the system was confirmed.

The development of electromobility involves the development of electric cars charging infrastructure. The increase of the number of chargers poses new demands for the AC power grid, especially in regard to its capacity of delivering high peak power. As an alternative for the public AC power grid, urban electrified transportation systems (trams, trolleybuses, and metro) can be used for supplying electric cars chargers. The article discusses four options of integrating electric cars chargers with a traction power supply system. The option of connecting the charger to the traction overhead supply line has been selected due to the spatial availability of the power source and possibility to use regenerative braking energy for charging. A set of criteria has been developed for analysing the capability of the traction supply system to feed electric cars chargers. An exemplary feasibility analysis was carried out for trolleybus traction supply system in Gdynia, Poland. The impact of installing the charging station on specific traction supply parameters has been predicted using present-state recordings of electrical parameters and assumed charging station power. The study shows that every supply section of the considered trolleybus traction system has the capability of installing a fast-charging station, which provides opportunities of expanding the charging stations network in Gdynia.

Electric rail vehicles use current collection system which consists of overhead contact line and a current collector (pantograph) mounted on the roof of a vehicle. A pantograph is equipped with contact strips, which slide along the contact wire, ensuring steady electric contact. Contact strips are made of carbon layer, fixed to an aluminum carrier. The carbon layer wears down due to friction. Using overly worn contact strips increases the rate of contact wire wear and, significantly, the risk of contact line damage. Therefore, thickness of carbon strips has to be inspected periodically. In previous work a 3D-scanning system has been proposed for recording data of contact strips when vehicles pass an inspection point on a railway line. However, the system has to be complemented with data analysis algorithm to estimate the thickness of the carbon layer. Data processing has to be performed quickly and automatically to prevent faulty pantographs from being used. The main difficulty of wear analysis is caused by diverse altitude and tilt of scanned contact strips. To determine the smallest thickness of carbon layer, the carbon surface data have to be normalized with respect to an aluminum carrier. The location and shape of the aluminum carrier can be extracted from the registered data. Due to the fact that the profile of the carrier is highly distorted, a robust Whittaker approximation algorithm has been proposed in order to deal with the noise and the missing data.

This paper analyzes the results of a trial operation of a battery-based buffer station supporting a selected section of trolleybus power supply systems in Pilsen, Czech Republic. The buffer station aims to prevent the catenary from excessive voltage drops in a part of the route that is most remote from the traction substation. Compensation of voltage drops is carried out by continuously measuring the catenary voltage and injecting the current into the catenary if the voltage decreases below a preset value. The effectiveness of such a solution was evaluated by the analysis of numerous experimental recordings, both from the buffer station itself and from trolleybuses in operation. Further on, based on the recordings, a utilized battery capacity was estimated and a control method for decreasing the required capacity was proposed. The optimal capacity analysis, supplemented with an evaluation of required output current rating, was used to define the best storage technology for the considered application.