WO2021091190A1

WO2021091190A1 - Charging apparatus using ess apparatus

Info

Publication number: WO2021091190A1
Application number: PCT/KR2020/015199
Authority: WO
Inventors: 백주원; 김명호; 김호성; 류명효
Original assignee: 한국전기연구원
Priority date: 2019-11-05
Filing date: 2020-11-03
Publication date: 2021-05-14
Also published as: KR20210054247A

Abstract

The present application relates to a charging apparatus using an energy storage system (ESS) apparatus. The charging apparatus using an ESS apparatus, according to an embodiment of the present invention, comprises: the ESS apparatus for storing electric energy; and a direct current-direct current converter having a primary-side module connected in parallel with the ESS apparatus and a secondary-side module connected in series between the ESS apparatus and a target battery. Here, in the direct current-direct current converter, one end of the primary-side module and one end of the secondary-side module are connected to each other, both ends of the primary-side module are connected in parallel with the ESS apparatus, and the other end of the secondary-side module is connected in series with the target battery.

Description

Charging device using ESS device

The present application relates to a charging device for a battery such as an electric vehicle, and to a charging device using an ESS device capable of reducing the device capacity of a converter required for the charging device and increasing the charging system efficiency.

Recently, eco-friendliness due to environmental pollution and saving of energy resources due to lack of energy have been emphasized. Accordingly, the automobile industry is also developing an eco-friendly, high-energy-efficient electric vehicle to improve competitiveness. In recent years, thanks to performance improvement and cost reduction of batteries, etc., electric vehicles are becoming a reality as a vehicle for general use.

However, in order to commercialize electric vehicles, the battery capacity is gradually increasing, and the battery charging voltage is also increasing in order to cope with the increase in battery capacity. Accordingly, the charger output voltage is also increasing to 1000V. In addition, in order to respond to the demand for rapid charging of the battery, the capacity of the charger is also being increased in high voltage and high-capacity, and recently, large-capacity chargers of around 100-400kW are being developed.

For rapid charging of the battery, the charging current capacity must be increased in proportion, and the charger capacity increases in proportion to the product of the output voltage of the charger and the charging current. Therefore, since the capacity and size of a fast large-capacity charger are directly linked to the rapid charging time and the battery capacity, the capacity of the charger is increasing in proportion to the battery size and charging time with the existing technology.

As described above, large-capacity chargers are expected to take a considerable amount of time to be widely distributed to general consumers as the size of the device increases and cost increases, and space is insufficient to supply large-capacity rapid chargers to areas such as urban centers and apartment houses. There is a difficulty in expanding the receiving capacity.

The present application aims to provide a charging device using an ESS device capable of reducing the device capacity of a converter required for the charging device and increasing the charging system efficiency while reducing the burden on the receiving capacity by utilizing the ESS device.

A charging device using an ESS (Energy Storage System) device according to an embodiment of the present invention includes an ESS device for storing electric energy; And a DC-DC converter in which a primary module is connected in parallel with the ESS device, and a secondary module is connected in series between the ESS device and a target battery, wherein the DC-DC converter comprises one end of the primary module. And one end of the secondary module are connected to each other, both ends of the primary module are connected in parallel with the ESS device, and the other end of the secondary module may be connected in series with the target battery.

Here, the ESS voltage of the ESS device is lower than the discharge end voltage of the target battery, and the DC-DC converter may apply an output positive voltage to the target battery and an output negative voltage to the ESS device.

A charging device using an ESS (Energy Storage System) device according to another embodiment of the present invention includes an ESS device for storing electrical energy; And a DC-DC converter in which a primary module is connected in series between the ESS device and a target battery, and a secondary module is connected in parallel with the target battery, wherein the DC-DC converter comprises one end of the primary module and One end of the secondary module is connected to each other, the other end of the primary module is connected in series with the ESS device, and both ends of the secondary module may be connected in parallel with the target battery.

Here, the ESS voltage of the ESS device is higher than the maximum charging voltage of the target battery, and the DC-DC converter may apply an output positive voltage to the ESS device and the output negative voltage to the target battery.

Here, the DC-DC converter may be an insulated converter having an insulating structure.

A charging device using an ESS (Energy Storage System) device according to another embodiment of the present invention includes an ESS (Energy Storage System) device for storing electrical energy; A first DC-DC converter in which one end of the primary-side module and one end of the secondary-side module are connected to each other, and the ESS device is connected in parallel to the primary-side module; And a second DC-DC converter in which one end of the primary module and one end of the secondary module are connected to each other, and the target battery is connected in parallel to the secondary module, wherein the secondary module of the first DC-DC converter The other end of and the other end of the primary module of the second DC-DC converter may be connected in series with each other.

Here, when the voltage of the ESS device is lower than the voltage of the target battery, the first DC-DC converter operates, the second DC-DC converter bypasses, and the voltage of the ESS device is If the voltage is higher than the voltage, the second DC-DC converter may operate, and the first DC-DC converter may bypass.

In addition, the solution to the above-described problem does not enumerate all the features of the present invention. Various features of the present invention and advantages and effects thereof may be understood in more detail with reference to the following specific embodiments.

According to the charging device using the ESS device according to an embodiment of the present invention, since the ESS device is used, the burden on receiving capacity can be reduced.

According to the charging device using the ESS device according to an embodiment of the present invention, the sum voltage of the ESS voltage and the converter voltage of the DC-DC converter is applied to the target battery through a DC-DC converter connected in series to the ESS device. I can. Accordingly, it is possible to simultaneously reduce the device capacity required for the DC-DC converter and minimize the conversion loss occurring in the energy conversion process.

However, the effects that can be achieved by the charging device using the ESS device according to the embodiments of the present invention are not limited to those mentioned above, and other effects not mentioned are the technical fields to which the present invention belongs from the following description. It will be able to be clearly understood by those of ordinary skill.

1 is a block diagram showing a charging device using an ESS device according to an embodiment of the present invention.

2 is a circuit diagram showing a charging device using an ESS device according to an embodiment of the present invention.

3 is an equivalent circuit of a charging device using an ESS device according to an embodiment of the present invention.

4 is a block diagram showing a charging device using an ESS device according to another embodiment of the present invention.

5 is a block diagram showing a charging device using an ESS device according to another embodiment of the present invention.

6 is a block diagram showing a charging device using a conventional ESS device.

Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. However, in describing a preferred embodiment of the present invention in detail, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, the same reference numerals are used throughout the drawings for parts having similar functions and functions.

In addition, throughout the specification, when a part is said to be'connected' with another part, it is not only'directly connected', but also'indirectly connected' with another element in the middle. Includes. In addition, "including" a certain component means that other components may be further included rather than excluding other components unless otherwise stated. In addition, terms such as "~ unit" and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software, or as a combination of hardware and software.

In the case of a charging device for an electric vehicle, etc., it can be configured in a manner in which direct current rectified from the input AC voltage is linked to a charger, and depending on the embodiment, in order to prevent the lack of receiving capacity, a separate ESS (Energy Storage System) It may further include equipment and a converter for linking it.

In general, an electric vehicle charging device may be composed of an insulated converter circuit according to the IEC (International Electronical Commission) standard, and a constant current for voltage fluctuations from the discharge final voltage of the electric vehicle battery to the maximum charging voltage. Control or constant voltage control can be performed. That is, initially, the charging current is supplied through constant constant current control, and then, constant voltage control may be performed after the battery of the electric vehicle reaches a constant charging voltage. Here, the isolated converter may be composed of various circuits, and a soft switching method may be used to improve efficiency.

In the case of the conventional electric vehicle charging device 10, as shown in FIG. 6, after receiving an input from the ESS device 11 to generate an output, it may be directly connected to the target battery 1 in parallel. Here, since the DC-DC converter 12 has a structure in which the ESS device 11 and the target battery 1 are connected in parallel on the input side and the output side, respectively, the DC-DC converter 12 is a device equal to the charging capacity of the entire system. It must be configured to have a capacity. However, as a recent demand for rapid charging of an electric vehicle battery, the charging capacity and the device capacity required for the DC-DC converter 12 are gradually increasing, and accordingly, problems such as economical efficiency and efficiency of the facility have arisen.

On the other hand, according to the charging device according to an embodiment of the present invention, it is possible to implement a structure in which the DC-DC converter bears only a part of the output capacity. That is, it is possible to reduce the device capacity required for the DC-DC converter, and at the same time, it is possible to increase the system efficiency by minimizing the conversion loss during power conversion in the DC-DC converter. Hereinafter, a charging device according to an embodiment of the present invention will be described with reference to FIG. 1.

Referring to FIG. 1, a charging device 100 using an ESS device according to an embodiment of the present invention may include an ESS device 110 and a DC-DC converter 120. Here, FIG. 1 corresponds to a case where the ESS voltage of the ESS device 110 is lower than the lowest voltage of the target battery 1, that is, the discharge stop voltage.

The ESS device 110 can store electrical energy, and the electrical energy stored in the ESS device 110 is supplied to the target battery 1 through the DC-DC converter 120 to charge the target battery 1. have. Here, the ESS device 110 may receive and store power from the grid power connected to the charging device 100, and depending on the embodiment, power from energy modules that produce renewable energy such as solar, wind, and hydropower It is also possible to receive and store. The target battery 1 may be a battery of an electric vehicle, and various types of batteries may be applicable.

The DC-DC converter 120 may convert a DC voltage or current output from the ESS device 110 into a DC voltage or current for charging the target battery 1. Specifically, as shown in FIG. 2, the DC-DC converter 120 may include a primary side module 121, a transformer module 122, and a secondary side module 123.

The primary-side module 121 may _{convert the input ESS voltage V ess} of the ESS device 110 into a first AC voltage. That is, in order to convert the received ESS voltage (V _ess ) into an output voltage corresponding to the target battery 1, the primary module 121 first converts the DC ESS voltage V _ess to the first AC voltage of AC. Can be converted. Here, the primary-side module 121 may include a plurality of switches and capacitors, and may _{convert a DC ESS voltage V ess} into a first AC voltage by switching operations of the switches. The operation of each of the switches may be controlled by a control unit (not shown), and the converted first AC voltage may be applied to the transforming module 122 afterwards. Here, the primary-side module 121 may be implemented as an insulated converter having an insulation structure, and is implemented in the form of various types of insulated converters such as the structure of the full-bridge converter shown in FIG. 2 and the half-bridge converter. It is possible.

The transformation module 122 may receive a first AC voltage from the primary-side module 121 and may transform the first AC voltage into a second AC voltage according to a set winding ratio.

The secondary module 123 may rectify the second AC voltage received from the transformer module 122 to generate a DC output voltage. The secondary module 123 may include a plurality of switches and capacitors, and may convert the second AC voltage into a DC output voltage by switching operations of the switches. Here, the operation of each of the switches may be controlled by a control unit (not shown), and the converted output voltage may be applied to the target battery 1. The secondary module 123 may be implemented in various types of insulated converter structures such as a full-bridge converter and a half-bridge converter.

Here, in the DC-DC converter 120 according to an embodiment of the present invention, as shown in FIG. 1, the primary-side module 121 is connected in parallel with the ESS device 110, and the secondary-side module 123 May be implemented to be connected in series between the ESS device 110 and the target battery 1. That is, one end (n1) of the primary-side module 121 and one end (n4) of the secondary-side module 123 are connected to each other by a connection lead (A), so that the secondary-side module 123 is connected to the ESS device 110 It can be implemented to be connected in series between the and the target battery (1). Through this, both ends (n1, n2) of the primary-side module 121 may be connected in parallel with the ESS device 110, and the other end (n3) of the secondary-side module 123 may be connected in series with the target battery (1).

With this structure, since only the difference voltage (V _ess -V _bat _{) between the ESS voltage (V ess} ) of the ESS device 110 and the battery voltage (V _bat ) is applied to the DC-DC converter 120, the DC-DC converter 120 can bear only part of the charging capacity. Accordingly, the device capacity required for the DC-DC converter 120 can be significantly reduced.

Meanwhile, FIG. 3 is an equivalent circuit of a charging device using an ESS device according to an embodiment of the present invention. Here, since the ESS voltage (V _ess ) is lower than the discharge end voltage, which is the minimum voltage of the target battery 1, the difference voltage (V _ess -V _bat ) is always less than 0. Accordingly, as shown in FIG. 3, the DC-DC converter 120 applies a positive output voltage to the target battery 1, and the output negative voltage of the DC-DC converter 120 is applied to the ESS device 110. So, an equivalent circuit can be implemented.

3, the total output power supplied to the target battery 1 is the product of the ESS voltage (V _ess ) and the charging current (i _ch ) of the ESS device 110 and the DC-DC converter 120. It is the sum of the product of the converter voltage (V _dc ) and the charging current (i _{ch ).} Therefore, in the total output power supplied to the target battery 1, the converter output power that the DC-DC converter 120 is responsible for becomes a part of the whole, and the _{lower the converter voltage (V dc} ) of the DC-DC converter 120 becomes. The converter output power becomes smaller.

This feature can act as a very big advantage in terms of efficiency. That is, the DC-DC converter 120 generally causes conversion loss, but since the DC-DC converter 120 only takes charge of a part of the total output capacity, the ratio of the loss to the total power of the system decreases in proportion.

The instantaneous efficiency of the entire system can be expressed as follows.

Here, η _system is the instantaneous efficiency of the entire system, V _bat is the battery voltage of the target battery 1, V _dc is the converter voltage output from the DC-DC converter 120, and V _ess is the ESS voltage of the ESS device 10 , i _ch is the charging current, and η _dc corresponds to the instantaneous efficiency of the DC-DC converter 120. Accordingly, referring to Equation 1, it can be seen that only a part of the amount of power and loss of the DC-DC converter 120 is reflected in the instantaneous efficiency of the entire system.

In addition, when the battery voltage (V _bat ) of the target battery 1 is charged from the discharge end voltage to the maximum charging voltage, the ESS voltage (V _ess ) of the ESS device 110 and the battery voltage of the target battery 1 are initially charged. The difference in (V _bat ) is very small and gradually increases. In other words, the difference voltage of the ESS voltage (V _ess) and battery voltage (V _bat) DC - As applied to a DC converter 120, the more increase the battery voltage (V _bat) of the target battery 1 is a direct current-direct current converter ( 120) converter output power gradually increases.

However, since the difference voltage is initially very small and gradually increases _{, the average value of the converter voltage V dc} corresponds to half of the difference voltage between the ESS voltage and the battery voltage after charging. That is, since the voltage applied to the DC-DC converter 120 is smaller when compared with the average voltage, the amount of output power and the loss ratio of the DC-DC converter 120 in the system instantaneous efficiency are reduced, and the system efficiency is reduced. You can see that it is rising.

Therefore, unlike the conventional charging device in which the overall system charging efficiency is consistent with the efficiency of the DC-DC converter, according to the charging device 100 according to an embodiment of the present invention, the loss of the DC-DC converter 120 is reduced as a whole. It can occupy a very small proportion of the system efficiency.

4 is a block diagram showing a charging device 200 using an ESS device according to another embodiment of the present invention, when the ESS voltage V _ess of the ESS device 110 is higher than the maximum charging voltage of the target battery 1 Corresponds to. In this case, since the difference voltage (V--V _bat _{) between the ESS voltage (V ess} ) and the battery voltage (V _bat ) is always greater than 0, the output negative voltage of the DC-DC converter 130 is used as the target battery (1). And the positive output voltage may be applied to the ESS device 110.

Therefore, unlike the charging device 100 using the ESS device of FIG. 1, the primary module is connected in series between the ESS device 110 and the target battery 1, and the secondary module is connected in parallel with the target battery 1. I can. That is, by connecting one end (n2) of the primary-side module and one end (n3) of the secondary-side module with a connecting wire (A), the primary-side module is implemented to be connected in series between the ESS device 110 and the target battery 1. I can. In addition, the other end n1 of the primary module may be connected in series with the ESS device 110, and both ends n3 and n4 of the secondary module may be connected in parallel with the target battery 1.

Here, the configuration of the charging device 200 using the ESS device according to another embodiment of the present invention is partially changed compared to the charging device 100 using the ESS device of FIG. 1, but the basic operation principle is the structure of FIG. same.

Additionally, according to another embodiment of the present invention, it is possible to implement the charging device 300 as shown in FIG. 5. That is, in the case of the charging device 100 of FIG. 1, the rated voltage of the ESS device 110 must be set below the discharge end voltage of the _{battery voltage (V bat ).} V _dc ) can make up a significant portion of the total voltage. Accordingly, in another embodiment of the present invention, the rated voltage of the ESS device 110 and the rated voltage of the target battery 1 are the same, and a plurality of insulated DC-

DC converters

120 and 130 are connected to the input terminal and the output terminal. It can be implemented in a structure that is placed at the same time.

Specifically, as shown in Fig. 5, the first DC-DC converter 120 and the second DC-DC converter 130 have one end of the primary-side module and one end of the secondary-side module connected to each other. The other end of the secondary module of the 1 DC-DC converter 120 and the other end of the primary module of the second DC-DC converter 130 may be connected in series with each other. In addition, the ESS device 110 may be connected in parallel to the primary module of the first DC-DC converter 120, and the target battery 1 may be connected in parallel to the secondary module of the second DC-DC converter 130. .

In this configuration, when the ESS voltage (V _ess ) of the ESS device 110 is lower than the battery voltage (V _bat ) of the target battery 1, the first DC-DC converter 120 operates, and the second DC-DC The converter 130 may be controlled to bypass.

Conversely, when the voltage (V _ess ) of the ESS device 110 is higher than the target battery voltage (V _bat ), the first DC-DC converter 120 is bypassed, and the second DC-DC converter 130 is operated. So that the system efficiency and device capacity can be further optimized.

The present invention is not limited by the above-described embodiments and the accompanying drawings. It will be apparent to those of ordinary skill in the art to which the present invention pertains, that components according to the present invention can be substituted, modified, and changed within the scope of the technical spirit of the present invention.

Claims

In a charging device using an ESS (Energy Storage System) device,

ESS device for storing electrical energy; And

A primary-side module is connected in parallel with the ESS device, and a secondary-side module includes a DC-DC converter connected in series between the ESS device and a target battery,

The DC-DC converter is

One end of the primary module and one end of the secondary module are connected to each other, both ends of the primary module are connected in parallel with the ESS device, and the other end of the secondary module is connected in series with the target battery.
The method of claim 1,

The ESS voltage of the ESS device is lower than the discharge end voltage of the target battery,

The DC-DC converter is

A charging device comprising: applying a positive output voltage to the target battery and applying a negative output voltage to the ESS device.
In a charging device using an ESS (Energy Storage System) device,

ESS device for storing electrical energy; And

A primary-side module is connected in series between the ESS device and a target battery, and a secondary-side module includes a DC-DC converter connected in parallel with the target battery,

The DC-DC converter is

One end of the primary module and one end of the secondary module are connected to each other, the other end of the primary module is connected in series with the ESS device, and both ends of the secondary module are connected in parallel with the target battery. Charging device.
The method of claim 3,

The ESS voltage of the ESS device is higher than the maximum charging voltage of the target battery,

The DC-DC converter is

A charging device comprising: applying a positive output voltage to the ESS device and applying the negative output voltage to the target battery.
The method of claim 1, wherein the DC-DC converter

Charging device, characterized in that the insulated converter having an insulating structure.
In a charging device using an ESS (Energy Storage System) device,

ESS device for storing electrical energy;

A first DC-DC converter in which one end of the primary-side module and one end of the secondary-side module are connected to each other, and the ESS device is connected in parallel to the primary-side module; And

And a second DC-DC converter in which one end of the primary module and one end of the secondary module are connected to each other, and the target battery is connected in parallel to the secondary module,

A charging device in which the other end of the secondary module of the first DC-DC converter and the other end of the primary module of the second DC-DC converter are connected in series with each other.
The method of claim 6,

When the voltage of the ESS device is lower than the voltage of the target battery, the first DC-DC converter operates, and the second DC-DC converter bypasses,

When the voltage of the ESS device is higher than the voltage of the target battery, the second DC-DC converter operates, and the first DC-DC converter bypasses.