Components of EV Charging Station – Power Electronics, Charge Controller, Network Controller, Cables

Electric Vehicle Supply Equipment (EVSE) Technology

EVSE delivers electrical energy from an electricity source to charge an EV battery. The EVSE communicates with the vehicle to ensure that an appropriate and safe flow of electricity is supplied. EVSE units are commonly referred to as charging stations.

Charge stations incorporate a number of assemblies and controllers.

• The power electronics assembly is the guts of a charge station. Functionally, it supplies the power to the EV`s onboard battery charger. Physically, it`s made up of wires, capacitors, transformers and other electronic parts.
• The charge controller serves as the [street smarts" of the charge station. It oversees basic charge functions, like turning a charger on/off, the metering of power usage and the storing of key bits of real-time and event data.
• The network controller provides the brains of the charge station. It enables the station to communicate with its network (via an on-board telecommunications device) so that managers can monitor it and review historical event data. It also controls user access to a charging station through a series of white (authorized) or black (unauthorized) lists.
• The charge station cable and connector plug into the target electric vehicle. These components provide the conduit for a charge to be delivered.

Classification of EVSE Components in Detail

• Physical components, such as internal electronics, controllers, cord, EV-compatible plug and telecommunications devices to share data and enable network connections.
• Software applications to manage the charging, billing, driver access, and administration of an EVSE program.
• On-going service to maintain physical and software components as well as provide customer service to both EVSE owners and their driver constituents.

Physical Components

All charging systems take AC power from the grid and convert it to DC power at a suitable voltage for charging the battery.

In EV applications, Level 1 and Level 2 chargers are usually contained within the vehicle. In Level 3 charging systems however the charging functions are split between the charging station and the vehicle`s on board charger.

Level 1 and Level 2 Chargers

• Level-1 EV Charging (120 Volts): Level-1 electric vehicle charging supports 120 volts and can be done using a power cord and a control box that comes with most electric vehicles. All plug-in hybrids and electric vehicles can be charged at level 1 when plugged into a regular wall socket. Level-1 charging is very convenient and can be done at home. Level-1 EV chargers do not incur any installation cost and can simply be plugged in. The only drawback with level 1 chargers is that it is the slowest way to charge an EV and it takes approximately 16-18 hours to charge a 60-kWh vehicle. Level 1 charging works from a single phase AC power outlet and is suitable for private, domestic installations and these do not need authentication and billing.
• Level-2 EV Charging: Level-2 electric vehicle charging equipment supports currents up to 240V AC and requires the installation of electric vehicle supply equipment (EVSE) and electric wiring capable of handling higher voltage power. The time taken to charge a battery depends on its capacity and the pace at which it is charged. Depending on the power output and the car you`re charging, Level 2 charging offers 5 to 15 times more quickly than Level 1 charging. Charging through Level-2 chargers is much faster than Level-1; a 7 kW EV charger takes 7 to 8 hours to charge a 60-kWh vehicle. Level-2 chargers can be used for domestic or workplace environments such as homes and apartments, small workplaces, hospitality, and retail stores. If the charger is designed to work with public charging stations, as many Level 2 installations will be, it will most likely need to incorporate further intelligence to communicate with the charging station to verify that the user is authorised to draw power from that particular source and to allow it to bill the customer for the energy transferred unless charging is installed at home or as a free service in the workplace or shopping mall.Level 2 charging stations may use either single phase or three phase AC power from the grid.These self contained systems used for Levels 1 and 2 gives the charger the flexibility to connect to different AC charging sources
• Level-3 EV Charging (480 Volts): Level- 3 EV charging, also called DC fast charging, can charge compatible vehicles up to 80% in as little as 30 minutes. Level 3 chargers convert high voltage AC power into DC power for direct storage in EV batteries. DC fast charging is primarily designed for public charging stations. These systems are quite expensive as compared to level-1 and level-2 EV chargers. It takes approximately 20 to 30 mins to recharge an electric vehicle using DC (level-3) charging. DC (level-3) EV chargers have commercial applications as they are the right fit for vehicle fleets and public transport, such as electric buses, that require fast charging and can accommodate a large number of vehicles simultaneously. Level 3 chargers have the same functionality as the Level 1 and 2 chargers but with the very high power levels used, the AC/DC conversion and the power conditioning and control circuits become very large and very expensive requiring heavy duty components. It makes sense to carry out these functions in the charging station rather than the charger so that the equipment can be shared by many users. This allows major cost and weight savings in the vehicle`s on board charger and with a bigger budget for the charging station, more efficient designs may be possible. In this case the BMS (battery management system) must communicate with the charging station to control the voltage and current delivered to the battery since power control is not implemented within the battery.
• While putting some of the traditional charger functions into the charging station permits cost savings in the vehicle, the charging station will be correspondingly more expensive. Level 3 charging stations are currently much more expensive compared to Level 1 & Level 2 stations, though the costs are rapidly coming down. On top of the equipment cost itself, there is also the cost of providing access to the grid. Because of the high power requirements per station, these can`t just be connected to the grid anywhere, and in some cases, the electricity generating utility must provide a dedicated supply line capable of delivering the very high currents demanded.

Software applications

EVSE software is designed to manage and administer charge stations and their networks, and should not be confused with EV applications created to oversee the electric vehicle. The software functional elements are illustrated in Figure below. EVSE network software promotes the quick deployment and configuration of EV charge stations and facilitates a two-way flow of data between the charge station and its cloud-based network control centre.

This functionality allows operators to remotely configure, manage, and update charge station software; set and control driver access to charging; set pricing; manage billing; and run usage reports. Software applications also enable drivers to easily locate and reserve available charge stations. Software tools can also be configured to send notifications to operators (hardware/software issues) and EV drivers ([charge completed," and [charge station available.")

On-going operation and maintenance

Once EVSE systems have been deployed, the host (owners) may maintain and administer them with an in-house employee. Another option is to outsource their EVSE program management and maintenance to a third-party EV service company like EV Connect.

Such outsourcing may be contracted on a turnkey basis including:

• Setting up EV driver access controls
• Pricing consultation if applicable
• Customer support to site hosts and drivers
• Up-time monitoring
• Reporting
• Hardware and software maintenance and more

Use Cases of EV Charging in Different Environments

EV solution providers target all kinds of customers with state-of-the-art smarter, more reliable, more accessible, and emission-free solutions. The latest EV charging solutions have a compact design, high-quality AC wall boxes, DC fast charging with robust connectivity, and separate on-demand EV charging solutions for EV fleets. Some of the business use cases of the Electric Vehicle Charging Solutions are:

Residential Charging: EV Charging solution vendors provide easy to install EV chargers for individual houses, housing societies, and residential buildings. Home chargers are well integrated with proper safety features for people and electric vehicles. These chargers are compact, lightweight, have attached AC input cables and DC output cables, and provide flexibility to be used as portable chargers or to be wall-mounted. These chargers have more than 95% conversion efficiency, lowering the total cost of ownership of battery-powered vehicles.

Retail and Hospitality: By installing EV charging stations in these sites, network operators can boost the visibility and usability of their infrastructure. It can provide EV drivers with a useful service, forge relationships with property owners, and use marketing possibilities to reach a larger audience. The operator and site owner may both see an increase in revenue as a result of these benefits, which will also help promote more environmentally friendly transportation.

Public Charging: The growing number of public highway charging points has made driving EVs even more convenient and reliable. These charging stations make EVs a practical and appealing choice for individuals searching for a green substitute to conventional modes of transportation by enabling drivers to recharge while on lengthy excursions, minimizing range anxiety. Public charging stations use AC Type 2 chargers, which are suitable for general applications such as workplaces, businesses, malls, hotels, and public commercial charging. These systems are robust and durable and can be managed by centralized management software. EV charging solutions installed in public places offer simple plug-and-play devices and charge all the type 2 compatible vehicles. The admin can use RFID tags for user authentication and remotely manage the applications and energy costs through the software associated with these chargers.

Fleet Charging: As companies seek to save expenses and their carbon footprint, EV fleets are growing in popularity. Network operators offer helpful data that assist EV fleet managers in making more effective decisions, prioritizing charging sessions, and setting flexible access costs. EV Fleet charging solutions require a DC charger to support all types of vehicles and charging needs. These fast DC chargers come with cutting-edge technologies in hardware design and application software. They also allow seamless integration with payment platforms and are capable of firmware and software up-gradation over-the-air. These DC chargers can accommodate 30KW – 300 KW of EVs.

The Future of EV Charging

Electric vehicle charging infrastructure is moving towards utilizing renewable sources of energy like solar and wind, and vehicle-to-grid (V2G) or Bidirectional chargers are steps in this direction. On the other hand, to reduce range anxiety among EV owners and to make using EV chargers easier, wireless charging of electric vehicles is also creating a buzz in the automotive market space.

With the electric vehicle infrastructure falling in place, the industry looks forward to delivering e-mobility solutions that are not restricted to automobiles and developing capabilities to energize our highways, industrial fleets, businesses, cities, and utilities.