DC charging station is an important device for electric vehicle charging, which realizes DC charging of electric vehicles through specific working principle and composition. In this paper, the basic working principle and composition of DC charging station will be introduced in detail to help readers better understand the operation process of DC charging station.

Basic Composition of DC Charging Station

The basic composition of DC charging station includes several important components such as power unit, control unit, metering unit, charging interface, power supply interface and human-machine interface.

Power unit: power unit refers to DC charging module, which is one of the core components of DC charging station. The power unit is responsible for converting the incoming AC power into the DC power required by the electric vehicle. This conversion process requires the use of power electronics technology, so that AC power can be effectively converted into DC power.

Control unit: The control unit is the controller of the DC charging station, which is mainly responsible for controlling the functions and operations of the charging station. The charging station controller belongs to the category of embedded hardware and software technology, through the control unit, the user can realize the charging pile's power on, power off, output voltage and output current and other parameters of the control.

Metering unit: The metering unit is used to measure the charging process, including accurate measurement and recording of charging duration and charging power. This is very important for the charging management and cost settlement of electric vehicles.

Charging interface: The charging interface is the interface between the DC charging station and the electric vehicle, which provides a channel for power transmission. The design of the charging interface must comply with the relevant charging standards to ensure the safety and compatibility of charging.

Power supply interface: The power supply interface is used for the power supply of the DC charging station, usually three-phase AC power. The power supply interface converts AC power to the charging module by inputting components such as circuit breakers and AC smart meters.

Human-computer interface: The human-computer interface is usually in the form of a touch screen, which is used for interaction between the user and the charging station. Through the touch screen, users can issue charging commands, set charging parameters, and get charging status and other information.

The working principle of DC Charging Station

The working principle of DC charging station can be briefly summarized as the following steps:

Input AC power conversion: the input of the main circuit is three-phase AC power, which enters the charging module (power unit) after inputting components such as circuit breaker and AC smart meter. The charging module converts the three-phase AC power into a DC power source acceptable to the electric vehicle.

Charging control: The control unit is responsible for controlling parameters such as the charging module's power on, power off, output voltage and output current. Through the human-machine interactive interface (touch screen), the user can issue corresponding commands to control the working state of the charging station.

Charging process: In the charging process, DC voltage is loaded to both ends of the battery of the electric vehicle, and the battery is charged with constant high current. As charging proceeds, the voltage of the battery gradually rises until it reaches the nominal value, while the state-of-Charge (SoC) of the battery reaches more than 95%. At this point, the charging post switches to constant voltage and low current charging mode to maintain the state-of-charge of the battery and prevent overcharging.

Secondary Loop Function: In addition to the DC charging module and the charging station controller, the secondary loop of the charging station also includes components such as the card reader, display and DC meter. The card reader is used for card authentication, and the display provides charging mode setting and start/stop control operation. The secondary circuit also provides start-stop and emergency-stop operations, and the signal lamp is used to indicate the charging status (e.g., standby, charging, and full).

Conclusion

DC charging station is a system integration product that realizes DC charging of electric vehicles through components such as power unit, control unit, metering unit, charging interface, power supply interface and human-machine interface. The charging process is to charge the battery with constant high current by converting AC power to DC power, and then switching to constant voltage and low current charging mode to keep the battery charged. Meanwhile, the secondary circuit of the charging station provides functions such as card reading authentication, displaying charging status and start-stop control. The working principle and composition of the DC charging station are of great significance for understanding the electric vehicle charging technology and the use of the charging pile.

If you want to know more about the principle of electric vehicle charging station, please contact Anengji (Chengdu) New Energy Co., Ltd, which is the top manufacturer of electric vehicle charging station, and the technical experts can provide you with detailed answers!