With the advancement of technology, the future of the automotive industry, new energy, self-driving cars will certainly be the mainstream. Since it is the protagonist, charging the pile as its power provider is an indispensable part. As the infrastructure construction of the electric vehicle industry, the charging pile is receiving more and more attention from the central and local governments. Today, Xiaobian will share what is the principle of it and what kind of future there will be. On November 7, 2016, the National Development and Reform Commission and the National Energy Administration held a press conference to officially release the “13th Five-Year Plan for Power Developmentâ€, proposing to accelerate the construction of charging facilities and promote the development of electric vehicles: by 2020, new concentration will be launched. There are more than 12,000 power station replacements and more than 4.8 million distributed charging piles. Basically, a moderately advanced, intelligent and efficient charging infrastructure system is built to meet the charging needs of more than 5 million electric vehicles nationwide. Some experts predict that by 2030, the promotion of new energy vehicles will reach 50 million. It is estimated that by 2020, 20,000 charging stations and 5.07 million charging piles will be needed; in 2030, 140,000 charging stations and 50 million charging piles will be built. First-tier cities such as Beijing, Shanghai, and Shenzhen all responded to the national strategic policies of electric vehicles and introduced policy plans. By 2020, Beijing will basically build an interconnected, intelligent and efficient charging facility service network, which can guarantee the charging demand of 600,000 electric vehicles. The charging service radius of key areas is less than 0.9 kilometers. According to the “13th Five-Year Planâ€, Shanghai will fully build 651 public charging stations, 39 bus charging stations, 225 taxi charging stations and 3,495 sets of special charging piles for sanitation logistics. On August 9, 2017, Anhui Development and Reform Commission, Anhui Provincial Energy Bureau, Anhui Provincial Economic and Information Technology Commission, Anhui Provincial Finance Department, Anhui Provincial Housing and Urban-Rural Construction Department, Anhui Provincial Department of Transportation, Anhui Province Quality Technology The Supervision Bureau and the Anhui Provincial Price Bureau jointly issued the "Notice on the Construction Plan for Electric Vehicle Charging Infrastructure in Anhui Province (2017-2020)". The notice pointed out that by 2020, 200 special charging and replacement stations for buses will be built, sanitation and logistics. There are 100 special charging stations, 130 urban public charging stations, 30,000 decentralized public charging piles, 150,000 decent self-use charging piles for official and private vehicles, and 170 intercity fast charging stations to meet 200,000. More than one electric vehicle charging demand. Under such a wave of policies, the charging pile industry is developing rapidly, but for most ordinary consumers, the charging pile is still a new thing, and there are few related professional articles. This article will introduce the classification of charging piles and the basic working principle of DC charging piles. 1 Classification of charging piles The charging pile is divided into an AC charging pile and a DC charging pile. The former is commonly called "slow charge", and the latter is commonly called "fast charge." The charging AC charging pile charges the battery by converting the alternating current of the power grid into direct current by the "car charger" built in the electric vehicle. On-board charger (OBC: On Board Charger) currently has two main power types in the domestic market: 3.3kW (input: 220VAC/16A, output: the power of the charger is different depending on 3.3kW and 6.6kW. The DC charging pile is built-in. The power DC charging module, the charging pile itself converts the alternating current of the power grid into direct current, and the output current can be as high as 100A or more, so it is called “fast charging.†The charging mode of the electric charging vehicle by the alternating charging pile and the direct charging pile is shown in FIG. . DC charging piles can be classified according to different dimensions such as power size, number of charging guns, structural form, and installation method. Among them, the mainstream classification according to the structure form is to divide the DC charging pile into two types: an integrated DC charging pile and a split type DC charging pile. 2 Basic working principle of DC charging pile In the industry standard "NB/T 33001-2010: Technical Conditions for Electric Vehicles Off-Board Conductive Chargers" issued by the National Energy Administration, the basic components of DC charging piles include: power unit, control unit, and metering unit. , charging interface, power supply interface and human-computer interaction interface. The power unit refers to a DC charging module, and the control unit refers to a charging pile controller. As a system integration product, DC charging pile itself, in addition to the "DC charging module" and "charging pile controller" constitute the technical core, structural design is also one of the key points of the whole pile reliability design. The “Charging Pile Controller†belongs to the field of embedded hardware and software technology, and the “DC charging module†represents the highest achievement of power electronics technology in the AC/DC field. The basic process of charging is: Load DC voltage at both ends of the battery, charge the battery with a constant large current, the voltage of the battery gradually rises slowly, rises to a certain extent, the battery voltage reaches the nominal value, and the SoC reaches 95% (for different The battery, not the same), continue to charge the battery with a constant current and a small current. "The voltage has gone up, but the power is not full, it is not full, if there is time, you can use a small current to enrich." In order to realize this charging process, the charging pile needs to have a "DC charging module" to provide DC power; a "Charging Pile Controller" is required to control the "power on, power off, output voltage, and output current" of the charging module; The touch screen is sent as a command from the human-machine interface, and the controller sends the commands such as “power on, power off, output voltage, and output current†to the charging module. The simplest charging pile that is understood from the electrical level can be used as long as there is a charging module, a control panel and a touch screen; if the power-on, power-off, output voltage, output current, etc. are made into several keyboards on the charging module, then a charging module can Charged the battery. 200V-420VDC / 10A) and 6.6kW (input: 220VAC/32A, output: 200-420V/20A). The output current is small and the charging speed is slow, so it is called "slow charge". According to the matching electric vehicle, the AC charging pile converts the three-phase alternating current into the DC power that the battery can accept by the charging module (rectifier module) after the input circuit breaker and the AC smart energy meter, and then connects the fuse and the charging gun to charge the electric vehicle. . The secondary circuit is composed of a charging pile controller, a card reader, a display screen, a direct current meter, and the like. The secondary circuit also provides “start-stop†control and “emergency stop†operation; the signal light provides “standbyâ€, “charge†and “full†status indications; the display as a human-machine interaction device provides card swipe, charging mode setting and start-stop Control operation. The electrical principles of DC charging piles are summarized as follows: 1. The single charging module is currently only 15kW, which can not meet the power requirements. It requires multiple charging modules to work in parallel. It is necessary to have a CAN bus to achieve the current sharing of multiple modules. 2. The input of the charging module comes from the power grid, which is a high-power power supply, involving the power grid and personal safety, especially personal safety. It is necessary to install an air switch at the input end (scientific name is “molded case circuit breakerâ€), lightning protection switch and even leakage switch. ; 3. The output of the charging pile is high voltage and large current. The battery is an electric chemical and is easy to explode. To prevent the safety problem of misoperation, the output should have a fuse; 4. The safety issue is the highest priority. In addition to the measures on the input side, mechanical locks and electronic locks must be available. Insulation testing is a must. Venting resistors must be available. 5. Whether the battery accepts charging, this is not determined by the charging pile, it is determined by the brain of the battery, BMS. The BMS issues a command of "whether to allow charging, whether to terminate charging, how much voltage can be accepted, how much current is charged" to the controller, and the controller sends the command to the charging module. Therefore, it is necessary to implement CAN communication between the controller and the BMS, and CAN communication between the controller and the charging module; 6. The charging pile is also subject to monitoring and management. The controller needs to connect with the background through a network communication module such as WiFi or 3G/4G; 7. The charging electricity fee is not free, you need to install the meter, you need the card reader to realize the billing function; 8. The charging pile housing needs to have a clear indicator light, usually three indicator lights, indicating charging, fault and power supply; 9. The air duct design of the DC charging pile is the key. In addition to the structural knowledge of the duct design, a fan needs to be installed inside the charging pile, although each charging module has a fan inside. Considering the above details, DC charging piles are more complicated as a system. Figure 3 shows the electrical schematic diagram of the main circuit of a more detailed electrical block diagram of a single gun DC charging pile as a design reference. 3 Technical development trend of DC charging pile Regarding the technical development trend of DC charging piles, there are five directions worthy of attention: 3.1 Ultra-high power charging reactor - power dynamic distribution - flexible charging The characteristics of pure electric bus charging station centralized parking and operating route charging determine that its charging solution may evolve towards the direction of super power charging reactor. Pure electric taxis and logistics vehicles may even evolve in this direction. The demand for 30KW charging modules has become urgent, and the main driving force is that the demand for charging reactors is becoming urgent. Power dynamic allocation was first proposed by a company. Each power module relay was used behind each of the two modules. The two modules can be used for the left gun or the right gun. Later, another company proposed a new term for flexible charging. When you need high-power charging, when the current is very large, you can use other modules to use it. When the car comes, you can use it separately. There is a certain reason for this. The flexibility in the power grid has the meaning of increasing the power. The concept of flexible charging is also said to be the past. Different names are actually the same meaning. For DC charging piles of 180 kW and below, it is a pseudo-demand to talk about dynamic power distribution and flexible charging. Even the split type has little meaning, but double gun charging and equalizing may be practical. The application scenario of the charging reactor is that it can automatically allocate how much power to each vehicle according to the number of vehicles to be charged. This ensures that the power of the charging module is used to the utmost. When there are not many vehicles, each car is allocated a large amount of power and can be filled more quickly. This kind of application requires more relays to switch the power flow of the charging module, which will increase some hardware costs, and the reliability is also increased. Of course, the software of the charging controller needs to be upgraded. 3.2 Community parking lot ring smart charging The so-called smart charging, this is a very fashionable concept. The specific application scenario is: a lot of electric cars are parked in a community parking lot, and the central processing unit actively patrols and detects the battery power of each car, and automatically fills each car automatically at night. This is actually a flexible charging, and it is also necessary to install a supercharger in the community parking lot. The advantage of this approach is that it is more efficient than AC charging. Compared with installing several DC charging piles, the owner has the flexibility to wait for DC charging and the cost is much lower. 3.3 Household wall-mounted charging piles into the household appliance store, into the family Maybe we can be more optimistic. After solving the power distribution, in the future, when we have the ability to deliver China's excessive power supply to each residential area, consumers can decide to install DC charging in order to pursue a faster charging experience. The pile is still an AC charging pile, and the DC charging pile will be as small and beautiful as the home appliance. Wall-mounted DC charging piles will be just a necessity. The sales model of this kind of product is like selling electric heaters. It is sold in the mall and sold on JD and TMALL. This home-like product will remove some of the less critical components of the DC charging pile, and the charging controller and touch screen function can be done in a charging module-sized housing, but the mold will be very delicate. With the advancement of power electronics technology, the power density of charging modules is getting higher and higher, this trend will become possible. 3.4 “Light Storage†charging and discharging integration The concept of combining photovoltaic, charging and energy storage has a specific product, which is PowerWall. In the future, PowerWall will further develop and form a new type of charging station. The electric energy is in photovoltaic panels, electric vehicles, power grids and energy storage batteries. Flow freely between. The DC charging pile can be supplied by the grid to charge the electric vehicle, or can be provided by the photovoltaic panel, or can be provided by the energy storage battery. The energy of energy storage batteries, battery car batteries and photovoltaic panels can also be sold to the grid. 3.5 shared charging, free charging If you think about the future with the Internet's shared thinking, any personally installed charging stake can be provided to any other owner, meaning that all charging piles can be opened at any time. With Internet tools, it is easy for car owners to find idle personal charging piles. In the future, the charging station may have made an important connection node of O2O's Off-Line under the thinking of the Internet. As long as the owner is charging, it may have to wait 15 minutes at the charging station. The charging station will serve as an important advertising venue resource, which is not difficult to imagine. Smart Watch,Smart Watch Women,Sport Smart Watch,Heart Rate Smart Watch GANSU PINGLINAG ABAY SCIENCE&TECHNOLOGY CO.,LTD , https://www.yzwtech.com
