A DC Electric Vehicle (EV) Charger is a type of fast charger for an Electric Vehicle (EV) that uses direct current (DC) to quickly and efficiently supply the DC electrical energy needed to charge an individual EV. Instead of converting the standard alternating current (AC) provided by the power grid into usable AC electricity and then transferring the AC to the EV battery via conductive leads, the DC EV charger uses advanced technology to directly convert and deliver the high-voltage DC to the EV battery.
- Components of DC EV Charger
In the market, DC EV charger mainly fall into two categories: integrated type and split type.
Integrated DC EV Charger
- Based on its name, the product is designed with all the essential parts contained within one case/cup made of metal. The components include but are not limited to: a charger with human-machine interface, communication module (control board) and safety protection devices.
- Charger Module: The charger module is an integral component of the DC EV Charger that converts AC from the electric grid to DC as well as controlling both the voltage and the amount of current used by this device. The design is usually modular for ease of capacity expansion and maintenance.
- Cooling System: An air or liquid cooled system providing heat dissipation due to the high temperatures resulting from high power operation.
- • HMI: Displays charging status, cost, communication error message, etc. Can also be used for credit card swipe or code/QR code scanner via a mobile app.
- • Control and communication module: Used for dynamic power regulation and control protection of the DC EV Charger which communicates with the vehicle as well as the electrical grid and the background management system.
- • Safety protection devices include: Overvoltage/Overcurrent Protection; Insulation Monitor; Emergency Stop Switches; etc.
Split-Type DC EV Charger
The name itself suggests that it consists of two parts: the main unit and terminals.
- The main unit is the core of power conversion and control; it converts AC to DC, modulates the output voltage and current in accordance with charge requirements, and realizes fast charging.
- The terminals are primarily responsible for connecting to the charging gun, managing the state of the charging interface, detecting whether a vehicle is connected and user operations, controlling the start and stop of charging, and the real-time monitoring of the charging process to guarantee safety in charging.
Advantages of Split-Type DC EV Chargers Over Integrated Ones
- Split-type DC EV chargers can be configured with multiple terminals and more charging guns, while integrated ones generally have only two charging guns.
- Split-type chargers are usually used for higher power (above 480kW) main units, equipped with 8~16 charging guns with a granularity of 30kW~60kW. The smaller the granularity, the stronger the dynamic distribution capability.
- Due to their higher power, split-type terminals are generally equipped with liquid-cooled terminals, which can reach a power of 600kW~800kW.
- Safety Protection System of DC EV Chargers
The following is a description of DC charging equipment (off-board conductive charging) referred to as “chargers” in short:
- An auxiliary low-voltage power supplies circuit should have a rated voltage of 12 ± 1.2 V and a maximum current rating of 10 A.
- The following should be implemented in all chargers: 1) current backflow prevention device, 2) discharge function, 3) Insulation monitoring Device (IMD).
- The device controller can monitor the status of DC contactors C1 and C2, and switches S3 and S4, and control their on and off; the vehicle controller can monitor the status of DC contactors C5 and C6, and control their on and off.
- The vehicle controller can be configured with a low-voltage auxiliary power supply circuit detection function. If the electric vehicle provides its own low-voltage auxiliary power supply, it should be isolated from the charger’s auxiliary power supply, and no voltage output should be present at the vehicle-side low-voltage auxiliary power supply A+ and A-.
- Working Principle of DC EV Chargers
- Connection to the Power Grid: Interfaced to a three-phase AC input from the grid, typically at a 380 V AC level.
- AC/DC Power Conversion: The charging module converts the AC input to a high voltage DC output (typically 200-1000 V DC), and controls the amount of output power that the charger provides.
- EV Communication: To communicate with the EV’s battery management system (BMS), the charger will need to communicate with it via a suitable communication protocol (e.g. CCS) to confirm the current battery state of charge (SOC), temperature, and voltage, as well as the necessary charging profile of the battery.
- Energy transmission: Perform charging in CC/CV mode according to the instructions provided by BMS, while parameters like voltage, current, and temperature will be monitored in real time.
- Terminate charging: Stop power supply once the target battery level is reached or when manually stopped by the user and save charging data.
- Key Control Logic
Dynamic Power Distribution
Adjust output power according to grid load and vehicle needs.
For example, a 360kW charging station:
Minimum granularity: 30kW.
Equalizing charging mode-which distributes power more evenly, enables each charging vehicle to obtain the most balanced charging efficiency. It is suitable for the charging breaks of operating vehicle fleets.
Priority charging mode-which gives priority to charging vehicles with low battery levels for distribution, achieves maximum efficiency. It allows the waiting vehicles to quickly replenish power and optimizes the queuing waiting time.
- Development Trends of DC EV Chargers
High Power
- Objective: Enhance charging efficiency to reduce waiting time by users.
- Technology direction: Ultra-fast chargers above 1000kW-increase power density by paralleling a number of modules or using new materials such as GaN/SiC; liquid-cooled ultra-fast charging technology solves the problem of high-power heat dissipation and supports higher power output.
Modularization and Intelligence
- Modular design is utilized to combine several charging modules to satisfy numerous power requirements between 120 – 1,000 kW.
- IoT and AI integration provides the ability to manage and optimise your charging solution from a central point using software. IoT enables you to monitor your charging solution remotely so that you can receive alerts when faults are detected, and optimise the charging strategy by observing the load on the electric grid and user behaviour via AI.
Standardization and Compatibility
- Value Proposition • Unified communication protocols: Allow interoperability of vehicles with chargers of different brands; for example, CCS/GB/T compatibility.
- Global standard integration: Reduce equipment redundancy and cost increases caused by standard differences.
Energy Internet Integration
- V2G: Electric vehicle chargers using direct current can send electricity back through the electric grid for peak-shaving and frequency regulation purposes.
- Integration of photovoltaic-storage-charging: The integration of photovoltaic and energy storage systems allows for recycling green energy.
Cost and Environmental Protection
- Cost reduction: Save on equipment costs through bulk production, module reusability and new materials such as silicon carbide.
- Environmental Design: Consume less while dissipating heat, use recyclable materials, and reduce carbon footprint.
- Summary
The concept of “refueling-like charging speed” will gradually become a reality. With a DC EV charger, you can charge an electric vehicle’s battery to 80% in the time it takes to use the restroom.
With the development of AI technology and continuous optimization of power scheduling algorithms, the advantages of split-type DC EV chargers will become more prominent. They can concentrate charging when idle and charge in an orderly manner during peak periods, greatly improving charging efficiency.
if you would like to obtain a specific quote for DC ev chargers along with the installation support for the relevant model you purchase from us, do not hesitate to contact us.