CN1877952A - Electric automobile charging station - Google Patents

Abstract

The invention discloses four electric automobile charging station system schemes, wherein the optimum electric automobile charging station is composed of power supply system, energy reserving system, several non-separating high-frequency charger and charging station monitor system, wherein the power supply system transforms high-pressure AC voltage into low-pressure DC or 380V AC power for charging device; the energy reserving system is set between power supplying system and each high-frequency charger; when the charger doesn't work, the external power reserves energy-reserving medium for electric automobile accumulator within short time; each high-frequency charger connects charging monitor system through CAN bus; the electric automobile charging station can charge different patterns of electric automobile for different manufacturers.

Description

Electric Vehicle Charging Station

technical field

The invention relates to a large charging station for charging electric vehicles.

Background technique

With the depletion of fossil energy and the increasing pollution of the human living environment caused by the extensive use of fossil energy, the research and promotion of renewable energy and clean energy has become a major strategic issue for improving the human living environment and sustainable development. Automobiles are an important area of energy consumption. The development and promotion of electric vehicles is of great significance to the realization of energy diversification and sustainable development. The field of automobile industry and major industrial countries attach great importance to the development of electric vehicles. my country has included the development of electric vehicles in the key areas of the national medium and long-term development strategy. With the launch of the National Tenth Five-Year "863" electric vehicle major project and the promotion of EEF, DUP, and DOE major international cooperation projects, the development of electric vehicles in my country has made important progress. The announcement on the development of electric vehicles issued by the National Development and Reform Commission in 2005 marks a major step in the industrialization and commercialization of electric vehicles in my country; it will definitely promote the industrialization of electric vehicles in my country.

Electric vehicle charging stations are an important infrastructure for the industrialization and commercial operation of electric vehicles. Charging stations for electric vehicles in public places are different from charging stations in the traditional sense and have their own special technical requirements and characteristics. At present, there is no real charging station for electric vehicles in public places in my country. Existing charging stations still belong to the clusters of chargers established by using conventional chargers to charge specific models of electric vehicles. A charging station in a real public place should not be a simple collection of multiple chargers, but a special intelligent charging device and adaptation that can adapt to a variety of electric vehicles, a variety of battery systems, a variety of voltage levels and different battery capacities. A large charging station for business and technical management, an electric vehicle charging system that can charge multiple electric vehicles of different types produced by different manufacturers.

Although the industrialization of electric vehicles still has a long and arduous journey, only when electric vehicles enter the commercialization stage can the construction of charging stations for public places facing the society be put on the agenda. But the construction of charging stations in public places is not as simple as there is no direct dependence between the car and the refueling system. There is a close technical dependence relationship between the charging station and the electric vehicle, which is interrelated and affects each other. The construction of charging stations should be promoted simultaneously with electric vehicles, otherwise, it will hinder the development of electric vehicles.

Contents of the invention

In view of the above reasons, the object of the present invention is to provide an electric vehicle charging station that meets the requirements for building an electric vehicle charging system in public places.

In order to achieve the above object, the present invention adopts the following design scheme: a charging station for electric vehicles, which is characterized in that it is mainly composed of a power supply system, several single-unit isolated high-frequency chargers and a monitoring system for the charging station;

The power supply system consists of a high-voltage relay protection cabinet, an ordinary three-phase power transformer and a low-voltage relay protection cabinet; the high-voltage relay protection cabinet is connected between the high-voltage power grid and the high-voltage side of the power transformer, and the low-voltage side of the power transformer is The protection cabinet is connected to the power supply of each single-unit isolated high-frequency charger, and provides a neutral-grounded 3-phase AC power supply for the single-unit isolated high-frequency charger;

Each stand-alone isolated high-frequency isolated charger is connected to the monitoring system of the charging station through the CAN bus.

A power factor compensation device is also arranged in the power distribution circuit of the protective relay cabinet at the low-voltage side.

An electric vehicle charging station, which is mainly composed of a power supply system, a rectifier, a DC relay protection cabinet, several non-isolated high-frequency chargers and a charging station monitoring system;

The power supply system consists of a high-voltage relay protection cabinet, a step-down isolation rectifier transformer and a low-voltage relay protection cabinet; the high-voltage relay protection cabinet is connected between the high-voltage power grid and the primary side of the step-down isolation rectifier transformer, and the step-down isolation rectifier transformer The secondary side is connected to the low-voltage relay protection cabinet, and the low-voltage relay protection cabinet is connected to the AC input terminal of the rectifier;

The DC output terminal of the rectifier is connected to the DC relay protection cabinet, and connected to the power supply of each non-isolated high-frequency charger through the DC relay protection cabinet to provide DC power for each charger;

Each high-frequency charger is connected to the monitoring system of the charging station through the CAN bus.

The neutral point of the step-down isolation rectifier transformer is not grounded to form an isolated power supply.

A power factor compensation device is also arranged in the power distribution circuit of the protective relay cabinet at the low-voltage side.

The non-isolated high-frequency charger is a step-down/or boost-type non-isolated high-frequency charger.

An electric vehicle charging station, which is mainly composed of a power supply system, an energy storage system, a DC relay protection cabinet, several non-isolated high-frequency chargers and a charging station monitoring system;

The power supply system consists of a high-voltage relay protection cabinet, a step-down isolation rectifier transformer and a low-voltage relay protection cabinet; the high-voltage relay protection cabinet is connected between the high-voltage power grid and the primary side of the step-down isolation rectifier transformer, and the step-down isolation rectifier transformer The secondary side is connected to the low-voltage relay protection cabinet, and the low-voltage relay protection cabinet is connected to the input end of the energy storage system;

The energy storage system includes an energy storage charging device and an energy storage medium; the output end of the energy storage system is connected to the power supply of each non-isolated charger through a DC relay protection cabinet;

Each stand-alone isolated high-frequency isolated charger is connected to the monitoring system of the charging station through the CAN bus.

The neutral point of the step-down isolation rectifier transformer is not grounded to form an isolated power supply.

A power factor compensation device is also arranged in the power distribution circuit of the protective relay cabinet at the low-voltage side.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the stand-alone isolated electric vehicle charging station system of the present invention

Fig. 2 is a schematic diagram of the composition of the centralized and isolated electric vehicle charging station system of the present invention

Fig. 3 is a schematic diagram of another centralized and isolated electric vehicle charging station system of the present invention

Fig. 4 is a schematic diagram of the structure of the energy storage charging type electric vehicle charging station system of the present invention

Detailed ways

The following describes several electric vehicle charging stations with different structures in combination with the accompanying drawings, and briefly explains the main features of the charging stations with various structures.

Fig. 1 is a schematic diagram of the structure of the stand-alone isolated electric vehicle charging station system of the present invention. As shown in the figure, this type of charging station is mainly composed of a power supply system, several single-unit isolated high-frequency chargers and a charging station monitoring system.

The charging station is uniformly powered by the power supply system. The power supply system is composed of a high-voltage relay protection cabinet, an ordinary three-phase power transformer and a low-voltage relay protection cabinet; the high-voltage relay protection cabinet is connected between the high-voltage grid and the high-voltage side of the power transformer. The low-voltage side of the transformer is connected to the power supply of each single-unit isolated high-frequency charger through a low-voltage relay protection cabinet to provide a neutral-grounded 3-phase 380V50HZ AC power supply for the single-unit isolated high-frequency charger. Each stand-alone isolated high-frequency isolated charger is connected to the charging station monitoring system through a CAN bus with a communication rate of 125K.

In order to compensate for the reduction of the power factor of the grid, a power factor compensation device is also installed in the power distribution circuit of the relay protection cabinet at the low-voltage side of the charging station.

The advantages of the charging station with this structure are: the stand-alone isolated high-frequency charger that constitutes the charging station is a general standard product, and the power supply system (power distribution system) can use or adopt the current industrial standard transformation and distribution system. Its disadvantages are:

1. Since the charging station with this structure adopts the power transformer isolation of the power supply system and the two-stage isolation of the stand-alone isolation type high-frequency charger, the isolation loss is increased by about 3% compared with the single-stage isolation, and the system cost is high, which greatly increases the system cost. equipment costs.

2. The manufacturing cost of each isolated high-frequency charger constituting the charging station is high and the volume is large, and the isolated power loss is about 3%.

3. The charger equipment is complex and has low reliability.

In order to overcome the above-mentioned problem of high isolation loss of the single-machine isolated charging station, as shown in FIG. 2 , the present invention provides a centralized isolated electric vehicle charging station. As shown in the figure, this centralized isolated electric vehicle charging station is mainly composed of a power supply system, a rectifier, a DC relay protection cabinet, several step-down non-isolated high-frequency chargers and a charging station monitoring system.

The charging station is uniformly powered by the power supply system, which is composed of a high-voltage relay protection cabinet, a step-down isolation rectifier transformer and a low-voltage relay protection cabinet; the high-voltage relay protection cabinet is connected between the high-voltage power grid and the primary side of the step-down isolation rectifier transformer During the interval, the secondary side of the step-down isolation rectifier transformer is connected to the low-voltage relay protection cabinet, and the low-voltage relay protection cabinet is connected to the AC input terminal of the rectifier; the DC output terminal of the rectifier is connected to the DC relay protection cabinet, through the DC relay protection cabinet Connect with the power supply of each step-down non-isolated high-frequency charger to provide DC power for each charger.

The neutral point of the step-down isolation rectifier transformer is not grounded, which constitutes an isolated power supply and completes the isolation function, so that the high-frequency charger does not need to be repeatedly isolated.

Each high-frequency charger is connected to the charging station monitoring system through a CAN bus with a communication rate of 125K.

Similarly, in order to compensate for the reduction of the power factor of the grid, a power factor compensation device is also installed in the power distribution circuit of the relay protection cabinet on the low-voltage side of the charging station.

The advantages of this centralized isolated charging station are:

1. The first level of isolation is reduced, the isolation loss is low, the structure of the charging equipment is simplified without isolation, and the construction cost of the charging station is low.

Since this centralized isolated charging station adds a step-down and isolation rectifier transformer between the power supply system and the high-frequency charger, the centralized isolation is realized through this step-down isolation rectifier transformer, and there is no need for repeated isolation for the charging device. , Therefore, you can choose a non-isolated charger, thereby greatly reducing the isolation loss, and reducing the cost of equipment.

2. The rated efficiency of the charging station is high.

Since the centralized isolation charging station adopts the step-down isolation rectifier transformer for centralized isolation, for the power supply system, a non-isolated high-efficiency charger with reliability, conversion efficiency above 98%, and lower manufacturing cost can be selected, thereby improving It improves the system efficiency of the charging station, has a significant energy-saving effect, and greatly reduces the construction cost.

3. Since the centralized isolated charging station provides DC high-voltage power supply for each high-frequency charger through centralized rectification, the line transmission efficiency is high and the reactive power loss of the line is reduced.

Fig. 3 is a schematic diagram of another centralized and isolated electric vehicle charging station system according to the present invention. As shown in the figure, the difference between this centralized isolated electric vehicle charging station and the charging station shown in Figure 2 is that it uses a step-up non-isolated high-frequency charger with a conversion efficiency as high as 98%.

Since the charging station shown in Figure 3 uses a non-isolated step-up high-frequency charger with a conversion efficiency as high as 98%, the secondary side DC bus voltage of the rectifier can be lower, and the power supply efficiency of the charging station can reach more than 96%. , The power factor exceeds 90% of the standard. The lower DC bus voltage can also greatly improve the safety of the charging station.

The problem with this kind of charging station is that the minimum output voltage of the charger is limited, and generally should be controlled at more than 50% of the rated voltage. If a larger voltage adjustment range is required, the centralized isolation type shown in Figure 2 should be selected. charging station.

From the analysis of construction cost and market operation cost of electric vehicle charging stations in cities, the rated load rate of charging stations should reach 80% to 85% to have good investment and operating economic indicators. The outstanding problem of the charging station is that the equipment utilization rate and the transformer utilization rate are very low. The low utilization rate of the transformer increases equipment investment and charging station capacity. An important way to reduce operating costs and charging standards is to reduce the investment cost of charging station equipment and the loss of charging stations. Therefore, the present invention proposes an energy storage charging type electric vehicle charging station that can greatly increase the utilization rate of the transformer and reduce the capacity of the power transformer of the charging station.

Fig. 4 is a schematic diagram of the structure of the energy storage charging type electric vehicle charging station system of the present invention. As shown in the figure, this energy storage charging electric vehicle charging station is mainly composed of a power supply system, an energy storage system, a DC relay protection cabinet, several non-isolated high-frequency chargers and a charging station monitoring system.

The charging station is uniformly powered by the power supply system, which is composed of a high-voltage relay protection cabinet, a step-down isolation rectifier transformer and a low-voltage relay protection cabinet; the high-voltage relay protection cabinet is connected between the high-voltage power grid and the primary side of the step-down isolation rectifier transformer During the interval, the secondary side of the step-down isolation rectifier transformer is connected to the low-voltage relay protection cabinet, and the low-voltage relay protection cabinet is connected to the input end of the energy storage system.

The energy storage system includes an energy storage charging device and an energy storage medium. The output end of the energy storage system is connected to the power supply of each non-isolated charger through the DC relay protection cabinet. Provide DC power to each charger.

The neutral point of the step-down isolation rectifier transformer is not grounded, which constitutes an isolated power supply and completes the isolation function, so that the high-frequency charger does not need to be repeatedly isolated.

Each stand-alone isolated high-frequency isolated charger is connected to the charging station monitoring system through a CAN bus with a communication rate of 125K.

In order to compensate for the reduction of the power factor of the grid, a power factor compensation device is also installed in the power distribution circuit of the relay protection cabinet at the low-voltage side of the charging station.

When the charger is not working, the external power is stored in the energy storage medium. When the charger is working and needs to charge the electric vehicle, the electric energy stored in the energy storage medium can be transferred to the battery of the electric vehicle with sufficient power in a short time. system to go.

The advantages of this energy storage charging station:

First, the calculation capacity of the power system of the charging station (such as power transformers and green energy such as solar power generation devices and wind power generation devices) can be significantly reduced. Take a fleet of 30 electric vehicles that need to supplement 200KWH of electric energy per day as an example. Assuming that 30 100KW chargers are configured, if the low-valley charging mode is used, the required coefficient is 0.7, and the coefficient is also 0.7, and a power transformer of more than 3000KVA is required. If the energy storage charging station architecture scheme is adopted, the calculated capacity of the power transformer is less than 300KVA, which is only equivalent to 10% of the conventional configuration. For most units, the problem of capacity expansion can even be avoided.

Second, the power system of the charging station operates in a good state of high transformer utilization, high power factor and low loss. Only the no-load loss of the transformer can save more than 50KW, accounting for about 16% of the calculated configuration capacity.

Third, it provides the possibility to obtain diversification of electric energy. The energy storage charging station makes it possible for green energy such as solar energy, wind energy, and discharge energy recovery to be used for charging high-power electric vehicles. Energy storage-based charging stations are the only viable design solution for energy diversification.

Fourth, you can make full use of low-valley preferential electricity prices to obtain economical energy.

There are many inconsistencies between the use of low-valley electricity price concessions and the operation and management of charging stations for electric vehicle charging stations designed with conventional design schemes. Especially for charging stations in public places, most of them require high-power emergency charging, which usually occurs during peak power consumption. The use of energy storage charging stations can better solve this problem.

Fifth, it provides an efficient and cheap way of energy recovery for the discharge of large-capacity battery packs in battery maintenance.

Claims (10)

1, a kind of electric automobile charging station is characterized in that: it mainly is made of electric power system, some unit isolated form high frequency chargers and charging station supervisory control system;

Described electric power system is made of high pressure relaying protection cabinet, common three-phase power transformer and low pressure relaying protection cabinet; High pressure relaying protection cabinet is connected between high-voltage fence and the power transformer high-pressure side, the low-pressure side of power transformer links to each other with every unit isolated form high frequency charger power supply by low pressure relaying protection cabinet, and 3 cross streams power supplys of neutral ground are provided for unit isolated form high frequency charger;

Every unit isolated form high-frequency isolation charger links to each other with the charging station supervisory control system by the CAN bus.

2, electric automobile charging station according to claim 1 is characterized in that: also be provided with power factor compensation device in described low-pressure side relaying protection cabinet power distribution circuit.

3, a kind of electric automobile charging station is characterized in that: it mainly is made of electric power system, rectifier, direct current relaying protection cabinet, some non-isolation high frequency chargers and charging station supervisory control system;

Described electric power system is made of high pressure relaying protection cabinet, step-down isolation rectification transformer and low pressure relaying protection cabinet; High pressure relaying protection cabinet is connected between high-voltage fence and the former limit of step-down isolation rectification transformer, and the secondary of step-down isolation rectification transformer links to each other with low pressure relaying protection cabinet, and low pressure relaying protection cabinet links to each other with the alternating current input of rectifier;

The dc output end of rectifier links to each other with direct current relaying protection cabinet, links to each other with every non-isolation high frequency charger power supply through direct current relaying protection cabinet, for every charger provides DC power supply;

Every high frequency charger links to each other with the charging station supervisory control system by the CAN bus.

4, electric automobile charging station according to claim 3 is characterized in that: the isolated neutral of described step-down isolation rectification transformer constitutes insulating power supply.

5, electric automobile charging station according to claim 4 is characterized in that: also be provided with power factor compensation device in described low-pressure side relaying protection cabinet power distribution circuit.

6, electric automobile charging station according to claim 5 is characterized in that: described non-isolation high frequency charger is the non-isolation high frequency of a voltage-dropping type charger.

7, electric automobile charging station according to claim 5 is characterized in that: described non-isolation high frequency charger is the non-isolation high frequency of a booster type charger.

8, a kind of electric automobile charging station is characterized in that: it mainly is made of electric power system, energy-storage system, direct current relaying protection cabinet, some non-isolation type high frequency chargers and charging station supervisory control system;

Described electric power system is made of high pressure relaying protection cabinet, step-down isolation rectification transformer and low pressure relaying protection cabinet; High pressure relaying protection cabinet is connected between high-voltage fence and the former limit of step-down isolation rectification transformer, and the secondary of step-down isolation rectification transformer links to each other with low pressure relaying protection cabinet, and low pressure relaying protection cabinet links to each other with the input of energy-storage system;

This energy-storage system comprises energy storage charging device and energy storage medium; The output of energy-storage system links to each other with the power supply of every non-isolation type charger through direct current relaying protection cabinet;

Every unit isolated form high-frequency isolation charger links to each other with the charging station supervisory control system by the CAN bus.

9, electric automobile charging station according to claim 8 is characterized in that: the isolated neutral of described step-down isolation rectification transformer constitutes insulating power supply.

10, electric automobile charging station according to claim 9 is characterized in that: also be provided with power factor compensation device in described low-pressure side relaying protection cabinet power distribution circuit.

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