This paper outlines a battery charging strategy to reduce charging losses in a lithium-ion battery for electric vehicles. The proposed charging strategy utilizes an adaptive current profile based on variations of the battery internal impedance as a function of the state of charge and charge rate. To address the problem of finding the optimal current set for the proposed strategy, an evolutionary algorithm, which is a type of stochastic approach, is applied. A strategy for selecting the optimal number of charging intervals is also presented to reach a compromise between loss reduction and computational burden. Experimental results obtained using 34Ah lithium-nickel-manganese-cobalt-oxide battery cells have proved that the proposed charging strategy decreases loss by 40.1% compared with a conventional constant-current charging strategy. Furthermore, a 3.3kW on-board charger prototype has been built to investigate the total loss reduction in an electric-vehicle charging system that includes a 12kWh battery pack. The proposed adaptive-current charging strategy reduces the total charging losses of electric vehicles by 7.2%, 11.2%, and 21.2% in charging systems with power ratings of 3.3kW, 6.6kW, and 13.2kW, respectively. These improvements can have the same effect as increasing the charger efficiency from a minimum of 0.50% to a maximum of 3.72% in our analysis range of 3.3kW to 52.8kW.

This paper proposes the advanced model of brushless dc motor drives considered behaviour of commutation and waveform of for dynamic simulation of automotive application under Matlab/Simulink environment. We need a model of BLDC motor drives that control algorithm and BLDC motor drive system can be designed and simulated as a point of system level. The model has to consider commutation phenomenon. A waveform of back-EMF of BLDC motor can be modified to depend on BLDC motor type. To satisfy above factors need a co-simulation technique with other circuit level simulation tools. However, there are severe constraints, i.e. simulation speed and interface with tools. The advanced model proposed in this paper considers behaviour of commutation and waveform of back-EMF for comprehensive analysis and prediction of dynamic characteristics of BLDC motor drives. The commutation phenomenon is implemented by functional behaviour description and back-EMF is modelled by pattern of waveform. The developed model is split into few parts with object-oriented manner for reusability and scalability. It is easily integrated with other models of automotive application.

Typical domestic induction cooktops can only heat ferromagnetic pots/vessels. However, to increase the availability and marketability of induction heating (IH) cooktop products, heating techniques for all types of metallic pots (i.e., created from metals such as aluminum, copper, and stainless steel) are required. To satisfy the requirements of induction cooktops, this paper proposes the design of an all-metal domestic IH system that can heat any type of metallic pot while considering the temperature variation of the working-coil. A control algorithm using a power curve-fitting method (CFM) is presented to quickly respond to load parameter variations in the IH. In addition, the CFM control algorithm is established to compensate for the power reference value by reflecting the increase in the working-coil temperature during the heating of the non-ferromagnetic pot. To evaluate the performance of the proposed system, the control algorithm strategy and experimental results based on a 3.2 kW all-metal IH cooktop are presented.

In this paper, an innovative modeling approach for Li-ion battery packs is proposed by considering intrinsic cell unbalances and packaging elements. The proposed modeling method shows that the accurate battery pack model can be achieved if the overall influences of intrinsic cell unbalances and packaging elements are taken account. Concurrently, the proposed method takes a practical model structure, resulting in the reduction of computational burden in a battery management system. Furthermore, because the proposed method utilizes cell information without a manufactured battery pack, it can be helpful to design optimal battery packs. The proposed method is verified through simulation and experimental results of the Li-ion battery pack along with the battery cycler. In three test profiles, the mean absolute percentage errors and root mean square errors of the proposed pack model do not exceed 0.5% and 0.07 V, respectively.

In power electronics applications where the switching frequency is below audible frequency, the acoustic noise and vibration design of magnetic components are as important as the efficiency. In case of the powder core, which is widely used in grid-connected inverters, many researches have been progressed in terms of efficiency and core loss. However, there are only few research have been progressed related with acoustic noise and vibrations. In this paper, the Sendust(Fe-Si-Al), MegaFlux(Fe-Si) and HighFlux(Fe-Ni) powder core materials which have low magnetostriction and low core loss are analyzed in terms of acoustic noise induced by Maxwell force and magnetostriction. Three types of powder core materials with rectangular shape are designed for a 4 kW grid-connected inverter. Various building structures, such as rectangular, toroidal, and oval shapes of a Sendust core, are compared with sound pressure level and efficiency. The effects of the magnetic flux density, Maxwell and magnetostrictive forces are analyzed by finite element method (FEM) and verified by in experimental results. In addition, experiment results of the sound pressure and inductor efficiency are presented according to core materials and building structures.