In this study, a review on high-frequency modelling in electric machines is conducted. Pulse-width modulation (PWM) creates common-mode-voltage (CMV) and common-mode-current (CMC) in electric drives with high-frequency impacts such as shaft voltage and bearing current which in turn cause bearing failures. To predict and reduce these failures in an electric machine, transitional modelling of high-frequency pulses is necessary. At the first step, several methods for high-frequency modelling in an electric drive are categorised. At the second step, several types of bearing currents discussed and CMV and CMC in electric drives are introduced. At the third step, CMV, CMC and bearing currents are simulated for six types of PWM methods and experimental verification is reported. Finally, root-mean-square value of a distorted parasitic current is introduced for comparing the electromagnetic effects of PWM methods.

The rapid conversion of automotive accessory loads to the electrical domain demands a power converter to interface between the on-board source and storage units with the accessories. This study proposes a simplified structure of dual input dual output (DIDO) with single-stage power conversion for hybrid electric vehicle accessory applications. The topology is synthesised using pulsating source cells. The generic switch model-based DIDO is realised with power switches based on switch realisation technique. Steady-state and equivalent circuit models describing the converter structure are presented. Numerical simulations were performed with the state-space averaged mathematical model. A one-step-ahead controller is used for inductor current control in conjunction with a mode selection logic to utilise its operating modes based on the availability of the sources and its protection. The performance of the proposed converter and its associated control scheme under steady-state, transient conditions are corroborated by simulation and experimental results.

To improve the current collection quality of pantograph-catenary system at high-operating speed, the effect of contact wire tension and messenger wire tension on catenary elasticity and contact force has been analysed, respectively, by adopting the finite element method, and which is analysed by introducing the moving standard deviation value and the moving average value. The results show that the influence of contact wire tension and messenger wire tension on elasticity of catenary between two droppers periodically is different and the non-smooth degree of elasticity at the dropper-point has a great influence on changes of contact force between pantograph and catenary. The smaller messenger wire tension is and the larger contact wire is, the smaller the change of non-smooth degree of elasticity at dropper-points is. When the pantograph runs at the speed of 500 km/h, the current collection quality can be improved effectively by decreasing messenger wire tension and increasing contact wire tension.

Important global efforts are underway toward lowering the cost of electric machines for electric and hybrid vehicles by reducing or eliminating the use of rare earth materials which have been experiencing significant price increases and volatility. This study will present several designs that reduce or eliminate rare-earth materials. All these designs are targeting the same set of specifications of 55 kW peak at 2800 rpm and 30 kW continuous over a speed range going from 2800–14,000 rpm. This provides a fair basis of comparison of various machine topologies. The study will provide a quantitative comparison of the performance of various machine topologies as well as highlight the key tradeoffs.

For system design, analysis of global performance and energy management of electric vehicles (EVs), it is common to use the efficiency map of electric traction drive. The characterisation of the efficiency map with high accuracy is then an important issue. In this study, an on-road method and an off-road method are compared experimentally to determine the efficiency map of electric drive of EVs. The off-road method requires a dedicated experimental test bed, which is expensive and time consuming. The on-road method is achieved directly in-vehicle. Experimental data, recorded during an on-road driving cycle, are used to determine the efficiency map using non-intrusive measurements from global positioning system antenna, voltage and current sensors. A versatile experimental setup is used to compare both methods on the same platform. A maximal efficiency difference of 6% is achieved in most of the torque–speed plane. It is shown that, in an energetic point of view, both methods yield similar results.

This study presents a loss-of-life (LoL) analysis for electric vehicle (EV) batteries, when they are being used as smart energy storage (SES) systems in a typical solar photovoltaic (PV) system installed in building environment. EVs can be considered as ideal energy storage for solar PV system installed in commercial/office buildings. This is attributable to the fact that the idle time-period of the EVs during the daytime, and the time-period during which the solar PV requires the energy storage intersect perfectly. However, it is to be demonstrated that using EVs as SES for solar PV system in commercial/office buildings would not have a significant impact on the battery lifetime and driving range of EVs. Hence, LoL analysis is essential to get a clear picture on the expected LoL for the EV batteries when EVs are used as SES for solar PV. Furthermore, the LoL of the individual EV batteries depends on the priority criteria used for charging/discharging the EVs, namely time coordinated and power coordinated vehicle-to-grid (V2G) algorithms. Hence, a comparison of LoL for different types of EVs while using different priority criteria in both the types of V2G is presented.

In this study, a two-dimensional analytical model has been presented for coaxial magnetic gears. Based on Maxwell's equations the extracted model has been obtained via the solution of the Laplace and Poisson equations by using the separation of variable technique for each sub-region (internal and external magnets, internal and external air gaps and slots). Then the integral coefficients of the general solutions have been obtained by using the boundary conditions and continuity between sub-regions. The proposed analytical model can be used as a tool for design and optimisation of magnetic gears. The influences of the number of pole-pairs, the magnetisation patterns, the size of slot-opening and the segment ratio of the two-segment Halbach pattern on the transmitted torque and unbalanced magnetic forces have been analytically investigated. Finally, to illustrate the efficacy of the proposed model, the analytical results of the magnetic field distribution, transmitted torque and unbalanced magnetic force have been compared with those obtained from finite element analyses.

In this study, a probabilistic approach for the optimal charging of electric vehicles (EVs) in distribution systems is proposed. The costs of both demand and energy losses in the system are minimised, subjected to a set of constraints that consider EVs smart charging characteristics and operative aspects of the electric network. The stochastic driving patterns for EVs’ owners, battery capacity and active and reactive power demanded at load nodes are considered. The optimal charging of EVs connected to the system benefits the system's operation, as it does a strategy to minimise the cost of energy losses and evaluate the capability of the system to charge EVs’ batteries fully under certain penetration scenarios. Priority periods of EVs’ recharge and the variation of energy price contribute to an adequate demand response, assisting the network operator for complying with quality indices (decrement of power losses) set forward by regulatory entities and developing studies of risk analysis for decision making. On the other hand, there is a valuable participation of the EVs’ owners in improving the operation of the distribution system. Monte Carlo simulation (MCS) is used to assess the stochastic nature of the problem in a secondary (low voltage) distribution network.

To study the offline characteristics of pantograph-catenary, finite element method was adopted in this study, and the coupled model of pantograph and catenary was established in the software of MSC. Marc to simulate the coupled motion of catenary and pantograph. First of all, relationship between distribution of catenary stiffness and contact force was analysed. It was obtained that the amplitude and variety of contact force were related to the stiffness of catenary, changing rate of stiffness and running speed of pantograph directly. In addition, the location, duration and space of offline were analysed under different speed, respectively. The results showed that offline often appeared at the location of smaller stiffness of catenary or higher changing rate of stiffness. Stiffness variety and running speed of pantograph have an influence on offline duration and spacing, and the shorter the duration, the bigger the spacing will be at the place where the rate of stiffness variety is high. The faster the pantograph runs not only the more offline points there will be but also the longer the duration will be as well as the bigger the spacing will be.