For the large-scale promotion of electric vehicles (EV), reliable fast-charging stations (FCS) demand high priority among EV users. However, unplanned locations of charging stations (CSs) and station capacity determination have adverse effects on the operation and the performance of power-distribution network. In this study, we developed an optimal FCS-planning model considering the aspects of EV users' convenience, station economic benefits, the impact on distribution systems and the effect on environment. A queuing-theory-based CS sizing algorithm that benefits EV users as well as improves CS capacity utilization was proposed. The proposed planning model was verified through a case study using real road network data by employing multi-objective binary and non-dominated sorting genetic algorithm. In addition, to evaluate the efficiency of the proposed sizing algorithm, sensitivity analyses for different EV penetration levels and station utilization were conducted. The simulation results show that the proposed CS-allocation model is beneficial in terms of achieving the satisfaction of EV users, cost savings, better station utilization, and less impact on power grids and the environment. Finally, to validate the effectiveness of the proposed planning model, a comparative study with one of the previous work on CS planning is also performed. The results demonstrate that the proposed charging station sizing method is highly efficient in optimizing EV users' satisfaction and for better station utilization.

For the applications related to the medium/high-power/voltage, Multilevel inverters are widely accepted and commercially used. The performance of MLI compare to the conventional two-level inverters is significantly superior due to the insignificant amount of harmonic distortion, lower filter size, requirement of low voltage rating devices, lower electromagnetic interference, etc. However, there are a few disadvantages such as an increased number of components, a complex modulation and control strategy, and issues related to the voltage balancing of capacitors. The present paper proposes a new topology with a lower voltage rating component to improve the performance by remedying the mentioned disadvantages. Compared with existing inverter topologies, (especially higher levels), this topology requires fewer components, fewer dc sources, and gate drives. Further, voltage stress is also low. The overall costs and complexity are therefore greatly reduced, especially for higher voltage levels. The proposed topology has been compared with other similar topologies and the comparison proves the better structure of the proposed topology. To show the working of the proposed topology, a prototype has been developed and tested for a different operating condition with two different modulation techniques. All the results show the adequate performance of the inverter topology at the different real-time environment.

The recent increase in electricity tariff and the introduction of feed-in tariff from renewable resources have increased the interest of energy consumers, such as those in commercial and residential buildings, in reducing their energy usage. This paper proposes a smart power socket and central control system that utilizes the Zigbee communication protocol to control energy usage. The system is designed such that smart sockets wirelessly provide the necessary data to a central controller. Then, the system analyzes the data to generate control commands to turn the devices attached to the smart socket on or off. Experimental results show that the proposed smart socket can correctly read the power consumption of wirelessly connected devices from up to 18 m away without loss of data. The central controller can effectively control multiple sockets on the basis of a scheduled user program code. A 24-min implementation of the proposed energy management algorithm shows a reduction of 0.811 kWmin (0.0134 kWh) in energy usage after the use of the smart sockets as load controllers. Thus, the proposed smart socket system can be fully utilized in a home energy management system with a proper scheduling algorithm.

In this work, a searching space minimization-based particle swarm optimization (SSM-PSO) scheme has been proposed for maximum power point tracking (MPPT) in a doubly fed induction generator (DFIG) based wind energy conversion system (WECS). DFIG displays non-linearity in $P-\omega $ characteristics. So different types of conventional and optimization-based schemes are developed for MPPT. The drawbacks in the conventional perturb and observe (P&O) scheme has been successfully abolished by the proposed SSM-PSO method. Because of its weather-insensitive nature, the conventional P&O MPP tracking scheme results in the fluctuation of DFIG output under a sudden change in wind speed. To avoid this problem, maximum and minimum limits for the optimal rotor speed have been determined in the proposed SSM-PSO scheme. Further, the obtained limits for rotor speed are employed to improve the searching space within the non-linear $P-\omega $ curve. This initial confinement of particles to a limited searching space in SSM-PSO results in a faster response of the system. Since the proposed SSM-PSO is atmosphere sensitive, it avoids fluctuations under an abrupt variation in wind velocity. The improved initialization part of SSM-PSO leads to better dynamic characteristics compared to existing P&O and optimization-based schemes. The proposed SSM-PSO scheme is implemented for a 2MW DFIG system in MATLAB Simulink atmosphere and showed satisfactory results.