What Are The Main Components of DC EV Chargers?

The rising awareness of environmental challenges has spurred a surge in electric vehicle adoption, making DC EV charging stations an essential feature in our urban landscape. These DC EV charging stations, now a common sight for eco-conscious drivers, house a variety of intricate components beneath their sleek exteriors. Let’s delve into the anatomy of these stations and explore the critical elements that keep electric vehicles powered and ready to go.

A Brief Introduction to Types of Charging Stations:

Charging stations are categorized based on voltage into Level 1, Level 2, and Level 3 charging stations.

Level 1 EV Charger: Relatively slow, providing a maximum of 120 VAC and up to 2.4 kW of charging power. This applies specifically to North America due to the unique voltage supply from the grid. In Europe, China, and elsewhere, this type of charger is known as MODE 2, also called ICPCD. Originally, it was limited to a power output of 230 Vac at a maximum of 7.4 kW, but it has now been improved to deliver 400 Vac at 22 kW.

Level 2 EV Charger: Faster chargers require 240 VAC with a maximum of 19 kW charging power. In Europe and other countries, the voltage for Level 2 charging is 400 VAC at 22 kW.

Level 3 EV Charger: Also known as DC fast charging stations, these are the fastest, operating with an input voltage of up to 480VDC and a maximum power of 360kW, which has now been advanced to 450kW.

Today, we will focus on the most complex components within the DC EV charging stations and briefly comprehend their operational principles.

 

Operational Principles of a DC EV Charging Station:

 

Power Input

The DC EV charging station’s power supply module needs to receive input power, typically alternating current (AC), which is then converted into direct current (DC) to supply the subsequent circuits.

Filtering

To ensure the normal operation of the subsequent circuits, the input power needs to be filtered. Filtering is usually achieved using capacitors and inductors to eliminate high-frequency noise and interference from the power supply.

DC/DC Converter

The filtered DC power needs to be transformed using a DC/DC converter. This converter adjusts the voltage of the power source to a level suitable for the subsequent circuits.

Control Circuit

The control circuit monitors the output voltage and provides feedback control. If the output voltage is too high or too low, the control circuit signals the DC/DC converter to make adjustments.

Output Voltage

After adjustment by the control circuit, the output voltage of the power module can be supplied to other parts of the charging station, such as the charger and the plug.

 

Important Components Of DC EV Charging Stations

 

Based on this operational principle, key components can be identified, such as:

Power Module:

The reason it’s called a DC EV charging station is that it directly charges the battery with direct current, whereas our grid supplies alternating current. Thus, the power module converts the incoming AC supply to DC and communicates with the electric vehicle’s Battery Management System (BMS) to dynamically adjust the voltage and current output. The power module typically consists of a power management module, controller, AC-DC converter, filter, communication module, and sensors.

40 kW Power Module of DC EV Charging Stations

The power module is the most critical and costly part of the DC EV charging stations, determining its efficiency and stability. Therefore, the kilowatt rating of a DC EV charging station is mostly determined by the module’s power. A high-quality power module not only enhances charging efficiency but also minimizes energy loss, helping the charging station recover its cost more quickly.

 

Charging Cable:

When we charge our electric vehicles at public stations, the DC EV charging station’s cable is usually thick and cumbersome. Some have humorously remarked that using the DC charging connector is akin to wrestling with a python, implying it requires considerable effort. The DC charging gun consists of a connector and cable designed to handle high currents, hence the need for thick cables. Although the current generation of high-power chargers (HPCs) has reduced cable diameters by using high voltage and low current, there is still room for improvement. Increasingly, supercharging stations are adopting liquid-cooled charging guns, which are more manageable in terms of size and weight, albeit at a higher cost.

ccs 2 connector of DC EV Charging Stationsccs 1 connector of DC EV Charging StationsCHAdemo connector of DC EV Charging Stations

What kinds of charging interfaces are there? As per current standards: CCS1: Combined Combo System 1 for the American standard. CCS2: Combined Combo System 2 for the EU standard. CHAdeMO for Japan, GB/T for China. NACS for Tesla Only.

charging Connector Types

Therefore, different standards incorporate different interfaces because each country’s electric vehicle designs employ different socket structures and communication protocols. Thus, when selecting a charging station, it is crucial to ensure compatibility with your EV’s charging interface.

 

Control Board:

The control board serves as the brain or heart of the DC EV charging stations, managing its operation and data collection. An excellent control board is vital for the reliability and safety of a DC charging station. A control board typically consists of a microcontroller unit (MCU), power management chip, communication interface chip, power switch chip, inverter, charging control chip, and display chip.

DC EV Charging Stations Controller

This control board fulfills several critical functions:

Communication with the EV’s BMS: obtaining data on the EV’s battery status, charging speed, and other parameters, which are essential for adjusting the charging speed and output power of the charging station.

Managing charging current and voltage: This task falls to the power management chip. After obtaining data about the EV’s battery, it regulates the voltage and current output to the EV battery, maintaining it in the optimal charging state to extend battery life and ensure charging safety.

Monitoring the charging process: This is the role of the charging control chip, which continuously communicates with the BMS, monitoring the entire charging process. It obtains data on the battery state, dynamically adjusts charging speed and time, and provides protection functions such as overload protection, short-circuit protection, and over-temperature protection.

Therefore, the quality of the control board determines the quality of the charging station. It can prevent inefficient charging, battery wear, and safety hazards.

 

Display Screen: Human-Machine Interaction System:

This integrates the software system, including a 4G module, WIFI module, OCPP software, etc. Users can control and adjust charging parameters via the touchscreen. Maintenance personnel can retrieve data and configure settings through the human-machine interaction module.

Applications of DC EV Charging Stations

Other components

Include AC contactors, AC circuit breakers, DC contactors, surge protectors, fuses, current transformers, air switches, relays, and fans.

 

Conclusion:

In conclusion, every component inside an electric vehicle charging station is crucial and has the potential to determine whether the charging station can be used stably. During the production of DC EV charging stations, even a single poorly connected wire can cause a charging station to malfunction.

Miles Energy is dedicated to meticulously inspecting every screw and cable, ensuring that our DC EV charging stations have an exceptionally long lifespan and stability.

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