Stator current of induction motor is analysed at single phasing by measuring phase angle, symmetrical components, Skewness, Kurtosis and harmonic distortion in Park plane. Diagnosis of single phasing of induction motor has been achieved by sequence components and stator current based pattern assessment. Distinct phase shift from 120° to 180° is observed between healthy phases. Patterns are formed using line currents and single phasing is assessed by using rule sets developed from features extracted from those patterns. Experimental result agrees with rule set and result obtained by assessment using sequence components. Then assessment is done by analysing wavelet decomposition based Skewness and Kurtosis of stator current in Park plane. At last, area based approach is used for assessment of single phasing and different distortion factors because of harmonics in Park plane are assessed. Accuracy increases with the increase of sampling rate of data acquisition system and use of Park plane has reduced computation effort by two-thirds. Thus single phasing is detected by sequence components supported by pattern formation and feature extraction and then harmonics during single phasing are assessed by wavelet decomposition and area-based approach in Park plane.

This study presents the recent application of energy storage devices in electrified railways, especially batteries, flywheels, electric double layer capacitors and hybrid energy storage devices. The storage and reuse of regenerative braking energy is managed by energy storage devices depending on the purpose of each system. The advantages resulting from the use of energy storage devices are presented by observing the results of both verification tests and practical applications in passenger services. Several real installations of energy storage for railways are shown and compared by using the Ragone plot. The effect of the use of energy storage devices on electrified railways of the future is discussed. Finally, a discussion on the recent applications and developments of energy storage devices is presented in this study. The effective use of energy storage devices is characterised on the basis of the specific applications and current trends of the research undertaken by public bodies and manufacturers.

The series–parallel resonant converter (also called line level control (LLC) resonant converter) is one of the most suitable topologies for dc–dc power supply. This study introduces the LLC resonant converter into the on-board battery chargers for the plug-in hybrid electric vehicle (PHEV) applications. Different from the previous literature which has focused on the wide operation range and hold-up time requirement in the LLC design, this study is mainly focused on battery load characteristics and its impact on the charger design. First, to guarantee high efficiency in the light-load condition in the constant voltage charging stage, the optimum LLC switching frequency range is derived. Second, considering the constant current charging function in the battery charger, the impact of peak load current on the LLC converter is discussed. The boundary between zero-voltage switching (ZVS) and zero-current switching (ZCS) in the constant current charging application is analysed. The trade-off among the minimum load voltage, maximum charge current and resonant capacitor is studied in detail. Finally, the optimal design method for the LLC resonant converter used in the PHEV battery charger is proposed. The proposed methods are validated through experiments on a 400 V/6 kW PHEV charger system with 97% efficiency.