Smart Charging Solutions for Hybrid and Electric Vehicles. Группа авторов

place. The increase in load is reflected in all segments and generation capacity must be increased to meet the demand. With an increase in the load, transmission line losses, transformers, and connected components increase. Further, deterioration of the distribution transformer’s life and the power quality on the distribution side is observed. Hence, the implementation of smart charging requires proper coordination with each unit of power system operators.

      Literature reveals the positive impact of smart charging on generation, transmission, and distribution systems. The requirement of additional generation due to the addition of load is substantially reduced in bidirectional smart charging. However, the uncertain availability of EVs is a concern during peak load hours. In the transmission system, smart charging helps improve grid security by performing economic operations and time ahead planning to cater to the requirements by scheduling the charging and discharging of EVs. Improvement in the regulation of voltage, frequency, and load management on the distribution side is one of smart charging’s goals [6, 24, 31, 38]. If smart charging is implemented, the assertion of a positive impact on the operators becomes a reality.

      1.5.2 Controllers

      Controllers are an integral part of smart charging. Smart charging is described in conjunction with power management, optimal control, and operation, satisfying the need for the PSO and EV user. Hence, a robust controller is required to meet the requirements. The controller decides on automatic scheduling, power flow, pricing, and the charging rate of EVs. Two types of controllers are widely discussed in literature: centralized and decentralized [9, 10]. When all the control actions are performed by a single controller connected to all other smart charging system entities, it is called a centralized controller. Alternatively, the distribution of control actions at different segregated units is described as decentralized control.

In decentralized control, a centralized controller is connected to all the decentralized controllers to perform central control actions. Each of the control techniques is described in subsequent sections of this chapter [48].

      1.5.3 Aggregators

      As the name suggests, aggregators aggregate EVs. Aggregators require group EVs connected at different charging infrastructure areas so that visible, beneficial impacts can be created in the utility grid. The aggregator interface is between the PSO and connected EVs at charging stations, homes, or any location to perform bidirectional or unidirectional charging. Further, the aggregator coordinates with the market to enable the participation of EVs. The aggregator provides the controller with required information to decide whether to enact generation or storage systems and provide ancillary services to the grid [49].

      In some cases, aggregators also act as decision-makers. For example, suppose the electricity pricing information is coordinated by the aggregator. In that case, the decision to command the charging locations based on pricing is performed by aggregators [50].

      A smart charging system might have one or multiple aggregators. EV owners have options to select their aggregators based on the benefits conferred. The aggregators help the PSO perform day-ahead planning. The planning includes deciding to buy or sell electricity prices; the aggregators’ data is sent to the PSO to help with on demand forecasting. The uncertainties involved in EV charging, such as arrival and departure timings, the power required to charge or available to discharge, and preferences of slow or fast charging are also dealt with by the aggregator. The uncertainty management involves the decision to store energy in local ESS during peak load hours and sell to the EV owners at any time. The use of local ESS helps minimalize the impact of charging on the utility grid [51-53]. The information exchanged by the aggregator requires robust communication systems to monitor and operate [54]. The details of the communication systems are explained in the next subsection.

      1.5.4 Communication System

The requirements of the communication system are already established based on the description of the above entities. Robust management, control, and operation of smart charging infrastructure depends on an effective communication system. Wired and wireless are two types of communication technologies used in smart charging infrastructure based on the area’s demography. The application of wired and wireless communication technology is made in different types of networks, such as a local area network (LAN), home area network (HAN), building area network (BAN), industrial area network (IAN), office area network (OAN), wide area network (WAN), field area network (FAN), and any many more, based on the location and definitions of the deploying organization [10, 13, 49, 54, 55]. A layout of the communication system to exchange information between different entities of smart charging systems is shown in Figure 1.4. All the entities connected by dotted lines depict the communication channels. The channels can be wired or wireless based on the requirements of the communication link to be established [55].

      Wired communication technologies, such as optical fiber cable, Ethernet cable, and power line communication (PLC), are suitable for long-distance data exchange. PLC has gained popularity over time. It uses the same power line to share information between connected entities and is more reliable and robust. HomePlug 1.0, HomePlug turbo, HomePlug AV, HD-PLC, and UPA are examples of charging protocols that use PLC [56, 57]. Optical fiber technology is also accessible due to the higher data rates offered.

Figure 1.4 Communication between various entities in smart charging infrastructure.

Moreover, a higher transmission range, less impact from electromagnetic interference, and increased reliability due to lower bit error rates are a few other perks to using optical fiber. Apart from PLC and optical fiber, a digital subscriber line (DSL) can also be used, especially in home setups for smart charging. DSL does not require any sperate communication line, but instead uses telephone lines for data exchange [58].

      Wireless communication setups are preferred in areas where connected devices are mobile. For example, in charging stations, the incoming and outgoing of EVs are uncertain. Hence, infrastructure developers prefer to use wireless communication technologies. Zigbee, WiFi, cellular network, WiMAX, and satellite networks are popular wireless technologies. The network used the most is called wireless LAN, which is a hierarchical mesh structure for data exchange [54, 58, 59].

      Note that more communication channels and entities can be added appropriately.

      1.5.5 Stakeholders

      The previous subsections described the components which actively participate in the operation and management of smart charging systems. Some entities are involved mostly in the planning stages but are not involved in real-time control. Such entities are manufacturers of various products for the deployment of smart charging, the service providers who perform regular maintenance, and the policymakers who promote the deployment and usage of EVs and the smart charging infrastructure. All are components of the smart charging infrastructure. Each of these is described in the next subsections.

       1.5.5.1 Policymakers

      Policymakers are individuals or organizations who participate in discussions and policy design processes for smooth and firm implementation of an idea. In the case of smart charging, policymakers focus on increasing EVs utilization in the transportation sector. With increased utilization, the requirements of infrastructure for charging EVs should also be considered. Hence, research and studies are performed to frame policies that converse consumers to think, plan, and use EVs. Policymakers are one of the integral drivers of the paradigm shift in using EVs in the transportation sector.

An example of policy is the Faster Adoption and Manufacturing of (Hybrid &) Electric Vehicles (FAME) by the Department of Heavy Industries under the Union Ministry of Heavy