With the increasing use of pure electric vehicles and more and more charging needs, the market puts forward higher and higher requirements for the safety and convenience of vehicle charging. Convenient, safe and fast charging is the consistent market demand for vehicles.1. New Energy Vehicle Power Supply Equipment (EVSE)Refers to the external charging equipment for charging plug-in hybrid vehicles and pure electric vehicles, including all power supply equipment connected to AC voltage and with charging plugs.2. AC charging (AC charging)It refers to the method of charging the power battery pack after rectifying the alternating current into direct current by the on-board charger.3. DC charging (DC charging)Refers to the method of charging the power battery by direct current.4. Charging Breaking Device (CCID)Refers to the leakage protection device in the charging line. When the leakage of the vehicle is detected, the CCID will interrupt the current between the charging cable and the vehicle.5. Charger (Charger)Refers to the equipment that converts the alternating current output from electrical equipment or other electrical energy supply equipment into direct current charging current. The on-board charger is installed on the vehicle, and the off-board charger is part of the EVSE.6. Charging plug (Charge connector)Also known as a charging gun, a device that is inserted into a car charging port to charge the power battery.7. Charging port/charging socket (Charging port/charge inlet)Refers to the electrical socket installed on electric vehicles and plug-in hybrid vehicles, usually behind the protective cover. The technical standard of the charging port or charging socket must be the same as that of the charging plug inserted into the vehicle in order to charge.8. Charging cable (Charging cable)Multi-refers to a portable charging device with one end plugged into the vehicle and the other end plugged into a 220V wall socket.　　9.充电桩(Charging station)A stationary device that delivers electrical energy to plug-in hybrid vehicles or pure electric vehicles, usually installed in home garages, workplaces, parking lots or public areas. According to the charging time, there are DC charging piles and AC charging piles.Secondly, we need to figure out which parts of the new energy vehicle charging system are composed.The role of new energy vehicle charging systemThe new energy vehicle charging system can provide energy supply to the power battery in time to ensure the normal operation of the power battery, and can adjust the charging current in time according to the power battery and the environmental status during charging.Composition of charging systemThe new energy vehicle charging system includes many components, including on-board charger, on-board charging interface, DC/DC converter and related wiring harness.1. On-board chargerThe main function of the on-board charger is to convert AC 220V commercial power into high-voltage direct current to charge the power battery and realize the supply of battery power. (According to the data provided by the battery manager BMS, the charger can dynamically adjust the charging current or voltage parameters, perform corresponding actions, and complete the charging process.)The on-board charger can be divided into three parts: main circuit (power circuit), control circuit, wiring harness and standard parts.1) The main circuit is divided into two parts. The front end converts alternating current into constant direct current, mainly a full-bridge circuit PFC circuit (PFC can be regarded as AC/DC). The back end is a DC/DC converter, which converts the DC high voltage transferred from the front end into appropriate voltage and current to supply the power battery.2) The control circuit, its core is the controller, which controls the switch of the MOS tube, communicates with the BMS, monitors the status of the charger, and shakes hands with the charging pile.The charger control board is mainly for the main circuit control, monitoring, measurement, calculation, correction, protection and communication with the outside network and other functions, is the “central brain” of the car charger “.When the on-board charger is connected to the AC power, the electric energy is not immediately output to the battery, but the BMS battery management system first collects, analyzes and judges the battery state, and then adjusts the charging parameters of the charger.3) The function of the wiring harness and standard parts is to connect the main circuit and the control circuit, and fix the components and the circuit board.2. On-board charging interfaceThe charging interface refers to the charging component used to connect the movable cable and the new energy vehicle. It is composed of a charging socket and a charging plug. It is a necessary equipment for a conductive charger. The charging plug is structurally coupled with the charging socket during the charging process., So as to realize the transmission of electric energy.GB/T 20234.2-2015 “electric vehicle conductive charging connection device part 2: AC charging interface”Rating of AC charging interface:The vehicle interface and the power supply interface of charging mode 3 respectively include 7 pairs of contacts, and their electrical parameter values and function definitions are as follows:Control pilot circuit: A circuit designed for signal transmission or communication between electric vehicles and electric vehicle power supply equipment.Control guidance function CP: a function for monitoring the interaction between electric vehicles and electric vehicle supply equipment.Connection confirmation function CC: a function that electronically or mechanically reflects the state that the vehicle plug is connected to the vehicle and/or the power supply plug is connected to the charging device.Contact arrangement:Charging connection interface:In the charging connection process, the protective grounding contact is first turned on, and the control guide contact and the charging connection confirmation contact are finally turned on. In the disconnection process, the guiding contact and the charging connection confirmation contact are controlled first, and finally the protective grounding contact is disconnected.The control pilot circuit performs the connection confirmation of the charging connection device and the judgment of the rated current parameter. The circuit consists of a power supply control device, contactors K1 and K2, resistors R1, R2, R3, R4, RC, diode D1, switches S1, S2, S3, an on-board charger and a vehicle control device, wherein the vehicle control device can be integrated In the on-board charger or other on-board control unit. The resistors R4, RC are mounted on the vehicle plug. The switch S1 is an internal switch of the power supply equipment. Switch S2 is an internal switch of the vehicle. After the vehicle interface is completely connected with the power supply interface and the interface configured with the electronic lock is completely locked, when the on-board charger has no fault after the self-detection is completed and the battery pack is in a rechargeable state, S2 is closed (if the vehicle is provided with the “charging request” or “charging control” function, the vehicle is in the “charging request” or “rechargeable” state at the same time). Switch S3 is the internal normally closed switch of the vehicle plug, and is linked to the push button on the plug (to trigger the mechanical locking device). When the button is pressed to release the mechanical locking function, S3 is in the open state. Switch S2 may not be configured in the control pilot circuit. Vehicles without S2 switch shall be charged with single phase and the maximum charging current shall not exceed 8A.