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Abstract on the topic of graduation work

Attention! This abstract refers to a work in progress. Estimated completion date: June 2021 Contact the author after the specified date for the final version.

Содержание

Introduction

Currently, more and more people around the world are using electric vehicles, which are becoming increasingly popular due to their environmental benefits and economic benefits. However, one of the main problems that electric car owners face is that charging stations for these cars are not nearly as common as gas stations for gasoline-powered cars. At the same time, more and more companies are realizing the importance of electricity for transport and are starting to build charging stations to meet the demand for electric cars. In this paper, we will discuss second-level charging stations, which are the most efficient and convenient way to charge electric vehicles.

Level 2 charging stations are devices that allow you to charge electric cars quickly and safely. They boost higher charging power than conventional home outlets and can charge a car for hours. These stations operate at a voltage of 240 volts and a power of 6 to 80 kilowatts.

One of the main advantages of Level 2 chargers is fast charging. Second-level charging stations use higher voltage and power than first-level charging stations, which allows charging electric vehicle batteries much faster. In addition, the second-level charging stations offer a wider range of functions, such as charging monitoring, charging management from a remote point, home power management and others. They allow you to charge the car for several hours, which is convenient for owners of electric vehicles who live in apartment buildings or are on trips.

Another advantage is the ability to monitor charging and its cost. With the help of special applications, you can control charging and set the price per kilowatt-hour. This allows you to save money on charging and monitor its process.

In addition, Level 2 charging stations have various connection options, including wired and wireless connection. This allows owners of electric vehicles to choose the most convenient charging method for them.

The charging standard is no less important feature than the interior dimensions and technical specifications. Moreover, it is relatively easy to choose the parameters, knowing in advance your preferences and financial capabilities.

The first standards of electric charges appeared in the United States. In this country, charging stations are divided into three types – Level 1, 2 or 3.

First–level electric charging stations are ordinary devices similar to household AC charging. With their help, you can charge an electric car for a trip of only 20-40 km in an hour. Most electric cars are charged at such a station for 8-12 hours.

AC Level 2 charging stations are stations that are connected to a conventional power grid. The speed is about twice as high compared to the first level. The average battery charge recovery time is 4-6 hours. Most of the modern American stations belong to this type.

Level 3 type – fast DC charging with a voltage of 480V and a power of up to 135 kW. It is rare, designed primarily for Tesla cars, the battery of which is charged in just 30-40 minutes by 80%.

In Europe, you can find charging stations that are divided into 4 varieties – no longer by level, but by mode:

Mode 1. The lowest-power station capable of being powered by a household power grid. The charging time of the electric car with its help is up to 10-12 hours. It corresponds to the American Level 1 type and is almost not used for modern electric vehicles.

Mode 2. A standard AC charging station, which is used both in everyday life and at gas stations. Suitable for electric vehicles of almost any type, with a traditional connector and a protection system inside the cable. The charging time of a standard electric car is up to 8 hours.

Mode 3. The most powerful mode for charging stations with alternating current. Compatible with Type 1 connectors (SAE J1772) for single–phase circuits and Type 2 - for three-phase. Charging time can reach from several minutes to 3-4 hours.

Mode 4. High-speed charging, using direct current instead of alternating current. The recovery time of the battery capacity of an average electric car is half an hour to 80%. The price of such stations is quite high.

Currently, despite the fact that electric vehicles have been mass-produced for more than 10 years, there is no single standard for either charging stations or connectors. European automakers are more likely to use Mennekes and CHAdeMO type chargers, American – CCS Combo and SAE J1772. There are standards in China, and some time ago Japanese companies used a separate type. The reasons for this situation are that each developer was sure that his version of the connector and charging system would be better and win the technology race.

In 2009, American developers from the SEA organization created and commissioned a 5-pin connector of the J1772 standard. It was intended for charging electric vehicle batteries from a conventional 220V AC network. The maximum power is 7.2 kW. At first, the standard was used only in the USA and Japan, but until 2016 several European models with such a connector were released. The modified standard allows you to charge batteries using a power of 90 and even 240 kW (current 450 and 600 A, respectively).

Since January 2013, in accordance with the plans of the European Commission for the development of eco-friendly transport, a new standard of connectors for electric vehicles has been adopted. It was called Type 2 or Mennekes, after the name of the developer company. This type is considered standard and the most common in Europe. For a single–phase network, the maximum power does not differ from Type 1 - 7.4 kW. For three-phase (380V), 43.5 kW is supported. The modified US version of the Type 2 allows you to charge Tesla cars with a power of 120 kW.

The fast charging standard supported by the automakers Nissan, Mitsubishi, Subaru and Toyota ("CHAdeMO Association"). Adopted in 2010, and its name stands for "charge de move" (fr. "charge for movement"). The power of charging stations using direct current is 50-200 kW, and the battery is charged by 80% within half an hour. The fast charging standard, which is supported by the automakers Nissan, Mitsubishi, Subaru and Toyota ("CHAdeMO Association"). Adopted in 2010, and its name stands for "charge de move" (fr. "charge for movement"). The power of charging stations using direct current is 50-200 kW, and the battery is charged by 80% within half an hour.

CS Combo is a universal standard of connectors for fast charging, the main European competitor of CHAdeMO. The first generation supports power up to 80 kW at a current of up to 400 V, the second – up to 350 kW (up to 1000 V). The connector allows you to charge batteries in different ways – slowly, but from household charging, quickly through a special connector or at high speed and using an external device. The advantages of the standard are the ability to connect to conventional networks.

The GB/T or IGBT connector is designed exclusively for the Chinese market, although charging stations supporting it can be found in the USA and Europe. It was created simultaneously with the invention of the first mass-produced Chinese electric vehicles since the early 2010s and was developed on the basis of the Type 2 port. Visually, GB/T actually resembles Mennekes, but is not compatible with it, therefore requires the use of other charging stations. By 2020, the CHAdeMO Association and the Chinese Electricity Council are going to produce cars with a common connector type that will be fully compatible with the old standards. Technical characteristics of the new port – support for power up to 900 kW at a current of up to 600 A and a voltage of 1.4 kV, the battery charging time of an average car up to 80% is no more than 15 minutes. The working name of the prototype, which is just getting ready to enter the market, is ChaoJi.

Standard charging stations use alternating current to charge the battery of an electric vehicle. If a single-phase network is used, the maximum voltage can only reach 220V, and the power does not exceed 7.4 kW. However, such indicators are not enough for a modern electric car with a power reserve of at least 200 km. You will have to charge it for the trip all night, and during the day the waiting time will be at least 5 hours. Therefore, a three-phase network is used for charging. An electric grid with a voltage of 380V allows you to charge the battery of an electric car several times faster. With the same current strength of 16A with single–phase sockets, the charging power increases to 10.5 kW, the maximum value is 43.5 (50) kW. The charging time from AC is no more than 6 hours, even for cars with a significant power reserve. However, such charging still cannot be called "high-speed". It is only "accelerated", and is suitable only in cases when the driver of an electric car has several hours of time, or the car is connected to the network at home.

Truly high-speed charging is performed using direct current. For this purpose, special batteries installed at charging stations are used. The absence of the need to convert the alternating current of the power grid into a constant battery of an electric car allows you to shorten the process several times. Instead of 10-12 or even 5-6 hours, it takes only 30-40 minutes to restore the battery capacity of an electric car. The advantages of such charging are high speed. But there are also disadvantages, because of which the technology is not yet as widespread as "slow" and "accelerated". These include the inability to charge the entire battery at maximum speed – only by 80%, after which the process slows down to standard values. In addition, fast charging stations are much more expensive to maintain, and the battery, which is constantly charged in this way, fails faster. Therefore, it is recommended to use high-speed technology only periodically, alternating it with regular charging from the network.

1. Theme urgency

The topic of "Level 2 charging stations" is extremely relevant at the moment. The growth in the number of electric vehicles in the world is continuously increasing, and with it the need for charging stations, which are a necessary element for their functioning. Currently, electric vehicles are increasingly attracting attention as an environmentally friendly and cost-effective mode of transport. However, one of the main limitations of using an electric vehicle is the battery charging time compared to refueling gasoline or diesel fuel.

In this regard, the need to develop the infrastructure of charging stations for electric vehicles is increasingly urgent. The installation of level 2 charging stations can significantly speed up the process of charging electric vehicle batteries, opening up new opportunities for their use in everyday life.

In addition, the development and use of efficient charging stations increase the competitiveness of electric vehicle manufacturers and increase consumer interest in this type of transport.

Thus, this topic is the subject of active study and development of research in the field of technologies for electric vehicles and is related to environmental, economic and technological issues, which makes it extremely relevant for modern society.

Master's work is devoted to the actual scientific problem of developing a positional electric drive system that is optimal in terms of energy consumption. The criterion for such optimization is, first of all, the minimum electrical losses in the armature winding, which is achieved by reducing the heating of the winding.

2. Goal and tasks of the research

  • Development of a second-level charging station for a load capacity of 22 kW

    • Main objectives of the study:

    1. Detailed overview of the charging station from Texas Instruments
    2. Simulation of all components and operation of the charging station
    3. Selection of hardware components

    Object of study:

  • A second-level charging station with a capacity of 22 kW.

    • Subject of study:

  • Dedevelopment of a second-level charging station with optimal characteristics and trouble-free operation.

    • 3. Overview of research and development

    Since second-level charging stations are an important part of the ecosystem of the automotive industry, they have been extensively studied by both American and European scientists and domestic specialists.

    Conclusions

    As a result of the work carried out, a second-level charging station was developed for a load capacity of 22 kW, including modeling of the charger built into the electric vehicle and its hardware. The developed station meets all safety requirements and standards. The development of a second-level charging station for a load capacity of 22 kW will speed up the charging process of electric vehicles and make the use of electric vehicles more comfortable for users.

    As part of the research carried out:

    1. The structure of the second-level charging station has been developed and the functions of its components have been determined.
    2. Based on the analysis of literary sources, the main methods that can be used in the proposed approach to optimizing the system for energy consumption are identified.
    3. The requirements for software and hardware are evaluated, the search for functionally similar charging stations from well-known manufacturers is carried out.
    4. A number of experiments on the use of various methods in optimizing the system for energy consumption, taking into account the static load, were carried out, the results obtained were analyzed.

    When writing this essay, the master's work has not yet been completed. Final Completion: June 2023. Full text of the work and materials on the topic can be obtained from the author or his supervisor after the specified date.

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