Extreme Fast Charging Technology—Prospects to Enhance Sustainable Electric Transportation

Abstract

With the growing fleet of a new generation electric vehicles (EVs), it is essential to develop an adequate high power charging infrastructure that can mimic conventional gasoline fuel stations. Therefore, much research attention must be focused on the development of off-board DC fast chargers which can quickly replenish the charge in an EV battery. However, use of the service transformer in the existing fast charging architecture adds to the system cost, size and complicates the installation process while directly connected to medium-voltage (MV) line. With continual improvements in power electronics and magnetics, solid state transformer (SST) technology can be adopted to enhance power density and efficiency of the system. This paper aims to review the current state of the art architectures and challenges of fast charging infrastructure using SST technology while directly connected to the MV line. Finally, this paper discusses technical considerations, challenges and introduces future research possibilities.

An Insight into Practical Solutions for Electric Vehicle Charging in Smart Grid

“…Detailed Description/Contribution [1][2][3][4][5][6][7][8] Smart grid, Grid modernization, Integration of EVs, EV chargers, and infrastructure-Centralized and decentralized controlled algorithm, Challenge, Load control through smart metering [9][10][11] Demand side management, Three steps-approach (offline/online optimization), online learning, EVs and integration of renewable energy [12][13][14][15][16] Optimal scheduling of LTC and SSC, Real time coordination of EV charging, EV charging impacts, charging schemes and strategies, Smart Load Management, EVs and integration of renewable energy [17][18][19][20][21] Power quality concerns, Impact of EV battery chargers on residential networks, Harmonics. [22][23][24][25] EV charging impacts, charging schemes and strategies, EV Standard SAE 2010-2017 [26][27][28][29][30][31] Smart grid-Integration of EVs, survey and analysis, Fast charging, Dynamic charging EV charging impacts and mitigation, [32] Power quality, Harmonics in power systems [33,34] EV charging fact sheets online datasheet-BWMi3, Idaho national laboratory [35][36][37][38][39][40][41]…”

“…Some manufacturers designed EV cars with fast charging facilities, and some provided their cars with sockets for charging. This can be either DC fast charging or AC charging [22][23][24][25][26][27]. The connections between the EV battery chargers and the charging stations as well as their communications depends on the type of battery charger (every manufacturer has its own specifications) and EV infrastructure [23].…”

“…The connections between the EV battery chargers and the charging stations as well as their communications depends on the type of battery charger (every manufacturer has its own specifications) and EV infrastructure [23]. The classification of the battery chargers as well as their connectors are thoroughly specified and presented in [24]. Generally, there are three important EV charging levels.…”

“…Level 1 charging (slow chargers), level 2 charging (medium chargers), and level 3 charging (fast chargers) according to SAEJ1772 standards [25][26][27]. Table 2 refers to the EV charging levels' characteristics, their power levels, and expected charging rate [24,25]. EVs can be charged overnight after plugging them into an outlet at home and charged overnight (slow charging).…”

“…The power quality is one of the main factors of the power distribution grid [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. The injected current harmonics caused by EV battery chargers may lead to severe consequences, such as power quality issues, voltage sag, increasing distortion, and power losses, especially with the growth in EV demand.…”