On board charger are the charging facilities for electric vehicles, and strengthening the research on the design of electric vehicle charging piles can promote the development of electric vehicles. The design of electric vehicle charging piles in underground garages is studied, and the load calculation of charging piles, the design of supply and distribution system, and the design of distribution and charging monitoring system are discussed in conjunction with engineering examples, which can provide useful reference for the design of similar underground garage on board charger.

In recent years, with the development of economy and the enhancement of people's low-carbon environmental protection concept, our government actively promotes the application of new energy vehicles. Electric vehicles, with their advantages of energy saving, environmental protection and cleanliness, have become a major direction for the development of new energy vehicles in the future. on board charger, as charging facilities for electric vehicles, are an indispensable part of the electric vehicle industry chain, and their design is related to the development of the electric vehicle industry. In view of this, it is important to study the design and application of electric vehicle on board charger.

Two important parameters in electric vehicles are the energy density of the power battery and the driving range. Lithium batteries currently have a service life of 5 to 8 years and a charge cycle life of 600 to 1,000 cycles. In order to keep the battery good and extend its life, it needs to be recharged when the power drops to 20% and stopped when it reaches 80% to 90% of the power. The range of electric vehicles used to be about 150km, but now it can reach more than 200km. With the improvement of the energy density of the batteries, the range of new products will reach more than 300km, which can basically meet the needs of most people for commuting and short-distance travel. According to the roadmap for the development of new energy vehicles, the popularity of electric vehicles will increase when they have a large driving range and short charging time. For the general population, with a range of 300 km, the driving range is about 120 km, and with an average daily commuting range of 40 km, each electric car needs to be charged 3 d, i.e. the ratio of parking spaces to charging piles is 3:1, and charging piles are set up at 30% of the total parking spaces.