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Electric Vehicle Charging Technology

Release time：

2023-05-10 13:24

Since the first electric vehicle was introduced in the 19th century, rechargeable batteries have been used as its power source. For an electric vehicle, battery charging equipment is one of the indispensable subsystems. Its function is to convert the electrical energy from the power grid into the electrical energy of electric vehicle on-board batteries. There are different methods for classifying electric vehicle charging devices, which can be generally divided into onboard charging devices and off board charging devices.
On board charging device refers to the device installed on the electric vehicle that uses the ground AC power grid and the on-board power supply to charge the battery pack, including the on-board charger, the on-board charging generator set and the operating energy recovery charging device. A AC power cable with a plug is directly inserted into the charging socket of the electric vehicle to charge the battery. Car charging devices typically use contact chargers with simple structures and easy control, as well as induction chargers. It is designed completely according to the types of on-board batteries and has strong pertinence. Off board charging devices, i.e. ground charging devices, mainly include dedicated chargers, dedicated charging stations, universal chargers, charging stations for public places, etc. It can meet various charging methods for various batteries. Usually, off board chargers have a relatively large power, volume, and weight to adapt to various charging methods.
In addition, according to the different ways of energy conversion when charging electric vehicle batteries, charging devices can be divided into contact type and induction type. With the rapid development of power electronics technology and converter control technology, the maturity and popularity of high-precision controllable electric power conversion, the phased constant current charging mode has been basically replaced by the constant voltage current limiting charging mode with continuous changes in charging current and charging voltage. The dominant charging process is still the constant voltage and current limiting charging mode. The biggest problem with contact charging lies in its safety and versatility. In order to meet strict safety charging standards, many measures must be taken on the circuit to ensure that the charging device can safely charge in various environments. Both constant voltage current limiting charging and phased constant current charging belong to contact charging technology. The new type of induction charging technology for electric vehicles is developing rapidly. Induction chargers use the transformer principle of high-frequency AC magnetic fields to induce electrical energy from the original side of the vehicle to the secondary side of the vehicle, in order to charge the battery. The biggest advantage of induction charging is safety, as there is no direct point contact between the charger and the vehicle. Even in harsh weather conditions such as rain and snow, there is no risk of electric shock during charging.