Sharing charging power system by time, solving the problem of electric vehicle charging

A brief introduction of accomplishments

Charging issue is the bottleneck of the current electric car development. Energy Internet innovation Tsinghua university institute of energy use Internet making use of "time-sharing" concept, independently research and develop the electric car sharing time-sharing charging power supply system, which can greatly improve the ability of power distribution network management charging pile. Charging pile number that unit area can be installed increases. It not only increases the sale of electricity, but also is convenient for the electric car owners.

Second, the charging pile installation

"A car is easier than charging!" Is the lot owner's confusion and gasoline vehicles to replace the huge resistance for electric cars.

Reporters found that after visited some old district distribution transformer capacity not enough situation is very outstanding. Among them 2010 years ago in the residential property management said, mostly due to the time of the transformer capacity design did not consider the electric car, so the late add charging pile become very difficult. In extreme cases, for example, a district a total of more than 1400 parking Spaces, the installation of the three after charging pile, substation box is already over-stretched. Now can't compatibilizing, if installed to increase capacity substation may burn at any moment.

It is difficult to solve the electric vehicle charging, is a system engineering, involves the ability of the distribution as a whole, is not a simple installation of charging piles can be solved. Charging pile is not fixed in the holes in the ground to play, then can pull wire, coordinate actual workload is quite large, mainly has four departments: users, car companies, power companies and property ownership. Refusing to install charging pile a few basic reason: charging equipment may cause safety accidents such as fire, leakage; Area capacity of power supply facilities, charging pile installation will affect the plot of the normal operation of power grid; Charging pile may affect other owner car out. One of the most important reason is "area capacity of power supply facilities, charging pile installation will affect the plot of the normal operation of power grid".

Parking lot in residential area of ordinary ac charging pile, almost all electric car owners exclusive, utilization rate is very low. Even the common places of public parking charging pile, may be more correct to think that it is exclusive, because the owner is almost impossible for waiting to be recharged in the vehicle, and then removed from the vehicle in a timely manner the next waiting vehicles enter the charge. So, for charging power supply, all of the plain charging pile are exclusive.

In addition to the ac power capacity limits, and three phase current balance. Serious unbalanced current problems will greatly reduce the utilization of the transformer, because any one phase current overrun will trigger circuit breaker tripping. If you are charging pile are focused on a certain phase, and the other basic load at this time just for this is not the biggest, which will be a lot to the possibility of a circuit breaker tripped.

Above all, sharing common charging pile is not easy, so whether can implement the power sharing in a charging power supply power box pile? Applying energy Internet thinking time sharing power supply is the solution to this problem.

Third, the sharing of time-sharing charging power supply system

Electric car sharing time-sharing charging power supply and its monitoring and control system design model shown in figure 2, including timeshare Shared distribution cabinets, power distribution management terminal and battery management cloud platform, etc. Based on the system, can realize intelligent charging user APP interaction guide, network billing and payment priority charging, etc., and can also use the valley electricity charge, fragments of time charging, etc., to realize the coordinated scheduling "car - pile - net".

Time sharing power distribution cabinet is the core of this system device. Can realize access of charging pile, exit and commutation operation, switching time is less than 5 ms, and no arc switch, operating life for 100000 times. At the same time, the time sharing distribution cabinets have the effect of charging pile with distribution network communication relay.

Distribution management terminal three phase current to detect the low voltage side of distribution transformer, according to the power limit, the real-time load distribution transformer (base load + charging load) and control command system, dynamic control of the normal charging pile of access, exit, commutation) power supply. When local high load distribution, removal or less access (including charging ongoing) charging pile load; When the real-time load hours, more access to the charging pile load. Probability is not balanced, because of the large base load in the access and exit charging pile, combining basic balanced three-phase load.

Cloud platform based on charging management, can develop a variety of functions and business, such as paid first charging, charging at valley power APP, user interaction, etc.Further excavations, owners own charging pile may also be in the form of a lease of other electric vehicle charging service, management organization and pile the sharing service.

Fourth, development prospects and business models

If the distribution transformer property ownership in the property company. Using Shared time-sharing charging power supply system solve the problem of common charging pile pile is easy, nothing to do with power companies apply for expansion. Independent property company can respond to a nation called on, on their own turf installation common charging pile, or rent the district electric car charging pile, and the surrounding area inside the village for the electric vehicle charging service, reasonable service fee, the increasing property income.

If the distribution transformer is public transformer, property rights belong to the power company. Power companies cooperate with property, property provides space, power companies provide distribution equipment. Property and reasonable service charge, power companies providing power, on the basis of ordinary sell electricity, by installing more charging pile, achieve more sell electricity, improve equipment utilization. At the same time, also can be in a larger range of electric vehicles as the schedulable load to guide way with intelligence, and in the low power load for electric vehicle charging, the charging at the peak load of power grid interrupt.

Five, the economic and social benefits evaluation

Direct benefit of time-sharing Shared charging power supply is pile can improve the operations of the charging car management ability, more profitable charging service revenue. In a 400 kva area to estimate can expand the number of charging pile. Figure 4 is a typical of the station area simplified curve of active power 24 hours a day. Set the power limit is 230 kw, if use ordinary electric vehicle power distribution box for charging pile, due to the peak of the margin is only 230-200 = 30 kw, install only 30/3.6 = 8 charging pile (normal charging).

Figure 4 simplified area typical day power curve

If the Shared time-sharing charging power box, only consider charging in the 0 to 6 h, can pile to 60, calculated as follows:

0 to 6 h of the transformer can provide rich electricity (230-50) * 6 = 1080 KWH. Assuming each car needs 18 KWH with 5 hours, the number of charging pile can be installed

1080/18 = 60 (a)

If 0 to 24 h are rechargeable, the transformer can provide rich electricity to 3020 KWH. Assuming each car needs 18 KWH with 5 hours, the number of charging pile can be installed

3020/18 = 167 (a)!

Per degree of family car run about 10000 km a year, go 7 km, a year of charge capacity per car as 10000/7 = 1428 (kWh).From 8 piles expansion to 60, the station area more than a year to sell (60-8) x 1428 = 1428 KWH. If expansion to 167, more than sell electricity 227052 KWH.

Six, the summary

Distribution capacity limit is one of the important factors in the expansion pack charging pile, old village is particularly prominent. Using the concept of energy Internet sharing time-sharing charging power supply system is the feasible solution of the problem, don't need expansion can be a lot of charging pile installation. The push our country the rapid popularization of the electric vehicle charging pile power management wide prospect of market. Institute of energy Internet innovation, Tsinghua university is committed to energy research new technology and new equipment, hope that through transfer and industry incubation model, such as promoting the development of innovation in the field of energy.

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