KR102535774B1 - battery charging station - Google Patents

Abstract

A battery charging station according to various embodiments of the present invention includes a plurality of storage boxes capable of accommodating a plurality of battery packs, a DC link capacitor for storing a DC link voltage, and converting an AC voltage of an AC power source into a DC voltage to convert the DC link voltage to the DC link voltage. An AC / DC converter that outputs to a capacitor, converts the DC link voltage into an AC voltage and outputs it to the AC power source, converts the DC link voltage into a battery voltage and outputs it to a corresponding battery pack among the plurality of battery packs , a plurality of DC / DC converters that convert the battery voltage of the corresponding battery pack into the DC link voltage and output it to the DC link capacitor, and manage the plurality of battery packs stored in the plurality of storage boxes, and use history Determining charging and discharging of each of the plurality of battery packs based on a demand prediction model generated by statistically processing data and electricity rates for each time period, and determining the charging and discharging of the AC/DC converter and the plurality of DC/DC converters according to the determination of charging and discharging. and a control unit configured to control the DC converter.

Description

Battery charging station {battery charging station}

The present invention relates to a battery charging station, and more particularly to a battery charging station capable of exchanging a battery pack for an electric two-wheeled vehicle.

In general, a two-wheeled vehicle is one that moves using two wheels, such as a bicycle that obtains driving power using pedals, a motorcycle driven by using a power source such as an engine or motor, and a kickboard that moves with one foot on the body and the other foot. etc.

Two-wheeled vehicles having a power source such as motorcycles are used as a major means of transportation today due to advantages such as ease of use, convenience of parking, and low fuel cost. In particular, the demand for two-wheeled vehicles is increasing due to the recent boom in the parcel delivery business due to the increase in Internet shopping, food culture familiar with delivery food, and the increase in users of two-wheeled quick service, and gasoline engines are widely used as a power source.

However, in recent years, due to environmental factors such as fuel efficiency, air pollution and noise, the number of two-wheeled vehicles using an electric motor as a power source is gradually increasing. A two-wheeled vehicle that uses a motor uses a battery as an energy source.

However, despite the rapid development of battery technology, not only does it take a considerable amount of time to fully charge a discharged battery pack, but also there is inconvenience in waiting for a turn for charging for a long time during times of high demand for charging.

The problem to be solved by the present invention is to provide a battery charging station for charging a shared battery pack for an electric two-wheeled vehicle.

A battery charging station according to an aspect of the present invention includes a plurality of storage boxes capable of accommodating a plurality of battery packs, a DC link capacitor for storing a DC link voltage, and converting an AC voltage of an AC power source into a DC voltage to convert the DC link capacitor to a DC link voltage. an AC/DC converter that converts the DC link voltage into an AC voltage and outputs the AC voltage to the AC power supply, respectively converts the DC link voltage into a battery voltage and outputs the battery pack to a corresponding battery pack among the plurality of battery packs; Manages a plurality of DC/DC converters that convert the battery voltage of the corresponding battery pack into the DC link voltage and outputs the DC link voltage to the DC link capacitor, and the plurality of battery packs stored in the plurality of boxes, and uses history data Determines charging and discharging of each of the plurality of battery packs based on a demand prediction model generated by statistical processing and a power rate for each time period, and determines the charging and discharging of the AC / DC converter and the plurality of DC / DC according to the determination of charging and discharging. and a control unit configured to control the converter.

According to an example, the control unit may include a memory for storing the usage history data obtained by statistically processing battery pack replacement times, electricity rate data for storing power rates for each time period, and the demand prediction model, and the plurality of boxes. and a main controller configured to determine charging and discharging of each of the plurality of battery packs based on a state of charge of each of the stored battery packs and data stored in the memory.

According to another example, the demand prediction model is generated using the usage history data, and outputs a predicted value of replacement quantity of battery packs from a current time to a reference time and upper and lower limit values of a confidence interval of the predicted replacement quantity of battery packs. can be configured to

According to another example, the reference time may be set based on a time for changing from a peak load time zone to a medium load time zone or a light load time zone, and a time changing from a medium load time zone to a light load time zone.

According to another example, the control unit outputs power stored in one of the fully charged battery packs to the AC power source when the number of currently fully charged battery packs is greater than the upper limit during a peak load time period in which electricity rates for each time period are high. The AC/DC converter and the DC/DC converter connected to the one battery pack may be controlled.

According to another example, if the number of currently fully charged battery packs is smaller than the replacement quantity prediction value, the control unit collects power remaining in an unfulfilled battery pack among the plurality of battery packs and fully charges one battery pack. The AC/DC converter and the plurality of DC/DC converters may be controlled to

According to another example, if the number of currently fully charged battery packs is less than the lower limit value, the control unit charges at least one of the plurality of batteries using the power of the AC power regardless of the current time to charge the AC// A DC converter and the plurality of DC/DC converters may be controlled.

According to another example, the usage history data may include an average and standard deviation of the number of exchanges for each time period.

According to another example, the controller may include a model updater configured to update the demand prediction model by reflecting the added usage history data when usage history data is added.

According to another example, the controller includes an AC/DC controller for controlling the AC/DC converter using a PWM control signal, and a DC/DC controller for controlling the plurality of DC/DC converters using a PWM control signal. can include

The battery charging station according to the present invention receives a discharged battery pack from the user and provides the charged battery pack to the user, thereby reducing the time required to charge the user's shared battery pack for an electric two-wheeled vehicle.

The battery charging station according to the present invention records the time at which battery packs are exchanged and processes them into statistics to predict replacement demand and determine charging and discharging of the battery packs based on this. During times when electricity rates are high, the remaining power in discharged battery packs is collected to form a charged battery pack, or by delaying the charging of battery packs during times when electricity rates are low based on a demand forecasting model, the battery pack can be recharged. Through this, not only can economic benefits be obtained, but also the total power consumption of the country can be reduced during peak hours when electricity prices are expensive.

1 schematically illustrates a battery charging station according to one embodiment.
2 shows a detailed configuration of a battery charging station according to an embodiment of the present invention.
3 illustrates a detailed configuration of a controller of a battery charging station according to an embodiment of the present invention.
4 shows an example of power rate data according to an embodiment of the present invention.
5 illustrates an example of use history data generated by statistically processing the history of users using a battery charging station according to an embodiment of the present invention.
6 is a diagram for explaining a demand prediction model according to the present invention.
7 is a diagram for explaining an exemplary operation of a battery charging station according to the present invention.
8 is a diagram for explaining another exemplary operation of the battery charging station according to the present invention.
9 illustrates an example of charging a battery pack of a battery charging station according to the present invention.
10 shows an example of an AC/DC converter of a battery charging station according to the present invention.
11 shows an example of a DC/DC converter of a battery charging station according to the present invention.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the embodiments taken in conjunction with the accompanying drawings. However, it should be understood that the present invention is not limited to the examples presented below, but may be implemented in various different forms, and includes all conversions, equivalents, and substitutes included in the spirit and scope of the present invention. do. The embodiments presented below are provided to complete the disclosure of the present invention and to fully inform those skilled in the art of the scope of the invention to which the present invention belongs. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded. Terms such as first and second may be used to describe various components, but components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals, and overlapping descriptions thereof are omitted. I'm going to do it.

1 schematically illustrates a battery charging station 100 according to one embodiment.

Referring to FIG. 1 , the battery charging station 100 includes a plurality of storage boxes 110, and battery packs 120 are stored in at least some of the storage boxes 110. The battery packs 120 are connected to the charging circuit of the battery charging station 100 .

At least some of the battery packs 120 stored in the boxes 110 may be fully charged battery packs 120a. In this specification, a fully charged battery pack refers to a battery pack to be provided after receiving a discharged battery pack from a user, and includes not only a battery pack having a state of charge of 100%, but also a battery pack having a state of charge equal to or greater than a preset value. I understand. For example, the preset value may be 80%, 90%, or 95%.

At least some of the battery packs 120 stored in the holders 110 may be charged battery packs 120b. In this specification, a charged battery pack means a battery pack whose state of charge does not reach the predetermined value, and power remaining in the charged battery pack can be used to fully charge other battery packs.

According to one example, the battery charging station 100 may be charging the battery pack 120b. When a demand for replacement of the battery pack is expected to be high, the battery charging station 100 may charge the battery pack 120b to make it a fully charged battery pack.

According to another example, the battery charging station 100 may be discharging the battery pack 120b. When the number of fully charged battery packs currently stored in the battery charging station 100 is greater than the predicted replacement demand for battery packs and during a time period when electricity rates are high, the battery charging station 100 transfers the power stored in the fully charged battery packs to the power grid. Electricity can also be sold by discharging.

According to another example, the battery charging station 100 may neither charge nor discharge the battery pack 120b. For example, if fully charged battery packs currently stored in the battery charging station 100 are not insufficient compared to an estimated demand for replacement of battery packs and the current power rate is high, the battery pack 120b will be charged after the power rate becomes low in the future. ), the battery pack 120b may not be charged.

According to one example, the battery packs 120 may be stored in each of the storage boxes 110 except for one 110e of the storage boxes 110 . The storage box 110e in which the battery pack 120 is not accommodated may accommodate the battery pack 120c discharged from the user. Although the battery charging station 100 is shown herein as having a total of 16 bins 110, this is merely illustrative. Among a total of 16 storage boxes 110, 15 storage boxes are filled with battery packs 120, and the other storage box 110e is empty. The storage box 110e means a storage box in which the battery pack 120 is not stored and is empty.

After storing the discharged battery pack in the empty storage box 110e, the user may take the fully charged battery pack 120a stored in the other storage box 110. In this specification, a discharged battery pack means a battery pack provided for replacement by a user who needs to charge the battery pack. A discharged battery pack does not just mean a battery pack with a 0% state of charge. That is, the discharged battery pack refers to a battery pack provided by the user to the battery charging station 100 for replacement of the battery pack. Usable power may remain even in a discharged battery pack, and the remaining power may be used to charge another battery pack. The battery pack provided by the user to the battery charging station 100 is a discharged battery pack, and if residual power remains in the provided battery pack, the discharged battery pack stored in the battery charging station 100 is a charged battery pack. can also be referred to as

At this time, the battery charging station 100 may charge the user and collect the cost from the user. The battery charging station 100 may charge a flat fee to the user whenever the battery pack is replaced. According to another example, the battery charging station 100 may charge a user a cost proportional to a difference between the remaining power amount of a fully charged battery pack and the remaining power amount of a discharged battery pack.

As shown in FIG. 1, the user stores the discharged battery pack 110e in the empty storage box 110e, and then uses one of the fully charged battery packs 120 (eg, the battery pack stored in the first storage box). 120a)). Accordingly, as shown on the right side of FIG. 1, the first storage box becomes an empty storage box 110e. If residual power remains in the battery pack 120c stored in the last container, it may be referred to as a charged battery pack.

The battery packs 120 include a fully charged battery pack 120a, a charged battery pack 120b, and a discharged battery pack 120c. The battery pack 120 includes battery cells, a protection circuit for protecting the battery cells, and a battery management unit for managing the battery cells.

Battery cells may include rechargeable secondary batteries. For example, a battery cell is composed of a nickel-cadmium battery, a nickel metal hydride battery (NiMH), a lithium ion battery, a lithium polymer battery, and the like. It may include at least one selected from the group.

The battery cells included in the battery pack 120 may be connected in series, in parallel, or in a combination of series and parallel. The number of battery cells included in the battery pack 120 may vary according to the requirements of a two-wheeled vehicle on which the battery pack 120 is mounted.

The battery management unit measures the voltage, current, and temperature of the battery cells, and operates a protection circuit when an abnormal state, such as full charge, full discharge, high current, or high temperature, occurs to electrically separate the battery pack 120 from an external circuit. can make it The battery management unit may include a sensing unit for measuring parameters of the battery cells and a control unit for controlling the protection circuit based on the parameters sensed by the sensing unit. The protection circuit may include a switch controlled by the battery management unit, a fuse, and the like.

2 shows a detailed configuration of a battery charging station 100 according to an embodiment of the present invention.

Referring to FIG. 2 , the battery charging station 100 includes a plurality of storage boxes 110 capable of accommodating a plurality of battery packs 120, an AC/DC converter 130, a DC link capacitor 140, a plurality of It includes a DC/DC converter 150 and a control unit 160. The controller 160 may include a main controller 161 , a memory 162 , an AC/DC controller 163 and a DC/DC controller 164 .

The AC/DC converter 130 converts the AC voltage of the AC power source 10 into a DC voltage and outputs it to the DC link capacitor 140 . The AC/DC converter 130 converts the DC link voltage of the DC link capacitor 140 into an AC voltage and outputs it to the AC power supply 10.

The AC power source 10 may be a commercial power source having a power grid consisting of power plants, transformers, transmission lines, and the like. The AC power source 10 may provide an AC voltage with a constant frequency and a constant magnitude. AC power source 10 may be a system.

The AC/DC converter 130 may generate a DC voltage by rectifying the AC voltage of the AC power supply 10 and may provide the generated DC voltage to the DC link capacitor 140 . Power stored in the DC link capacitor 140 may be used to charge the battery packs 120 . At this time, the AC/DC converter 130 may operate as a rectifier circuit.

The AC/DC converter 130 may generate AC power from DC power stored in the battery packs 120 and supply the AC power to the AC power source 10 . The battery charging station 100 can obtain power revenue by selling the power stored in the battery packs 120, and can reduce the total power cost through the power revenue. In this case, the AC/DC converter 130 may operate as an inverter circuit generating AC power from DC power. That is, the AC/DC converter 130 may operate as a bi-directional inverter.

The AC/DC converter 130 may be controlled by a PWM (Pulse Width Modulation) control signal provided from the AC/DC controller 163 .

The DC link capacitor 140 stores the DC link voltage. The DC link capacitor 140 may function as a smoothing capacitor for smoothing a DC voltage level.

Each of the plurality of DC/DC converters 150 converts the DC link voltage of the DC link capacitor 140 into a battery voltage and outputs the converted battery voltage to a corresponding battery pack 120 among the plurality of battery packs 120 . At this time, the battery pack 120 may be charged. The battery pack 120 may be charged with power supplied from the AC power source 10 or may be charged with power discharged from another battery pack 120 .

Each of the plurality of DC/DC converters 150 converts the battery voltage of the corresponding battery pack 120 into a DC link voltage and outputs the converted DC link voltage to the DC link capacitor 140 . At this time, the battery pack 120 may be discharged. Power stored in the battery pack 120 may be supplied to the AC power source 10 or used to charge another battery pack 120 . Each of the plurality of DC/DC converters 150 may operate as a bidirectional DC/DC converter.

The plurality of DC/DC converters 150 may be controlled by a PWM (Pulse Width Modulation) control signal provided from the DC/DC controller 164 . In FIG. 2 , the DC/DC controller 164 is shown as controlling the DC/DC converter unit 150a integrating the plurality of DC/DC converters 150, but the DC/DC controller 164 is a plurality of DC/DC converters. A plurality may exist corresponding to the /DC converter 150, and each of the plurality of DC/DC controllers 164 may control the corresponding DC/DC converter 150.

The plurality of DC/DC converters 150 respectively correspond to the plurality of storage boxes 110 . The DC/DC converter 150 corresponding to the empty storage box 110e may be deactivated.

The controller 160 manages the plurality of battery packs 120 stored in the plurality of storage boxes 110 . The control unit 160 determines charging and discharging of each of the plurality of battery packs 120 based on a demand prediction model generated by statistically processing usage history data and electricity rates for each time period. Usage history data, a demand prediction model generated based thereon, and data on electricity rates for each time period may be stored in the memory 162, and the main controller 161 may store a plurality of battery packs 120 according to the algorithm of the present invention. Each charge and discharge can be determined.

The battery charging station 100 according to the present invention may discharge some of the battery packs 120 and sell them to the AC power supply 10 or use them to charge other battery packs 120 .

The controller 160 controls the AC/DC converter 130 and the plurality of DC/DC converters 150 according to the determination of charging and discharging of each of the plurality of battery packs 120 . The control unit 160 may control the AC/DC converter 130 using the AC/DC controller 163 and the DC/DC converters 150 using the DC/DC controller 164 .

3 illustrates a detailed configuration of a control unit of the battery charging station 100 according to an embodiment of the present invention.

Referring to FIG. 3 together with FIG. 2 , the controller 160 includes a main controller 161 and a memory 162 . The main controller 161 includes a pack management unit 210, a charging/discharging determining unit 220, a model updating unit 230, a payment unit 240, and a reservation management unit 250. The memory 162 stores power rate data 260 , usage history data 270 and a demand prediction model 280 .

In FIG. 3 , the main controller 161 is shown as one functional block, but may be implemented with two or more control devices or two or more integrated circuits. Two or more control devices implementing the main controller 161 may be communicatively connected to each other. For example, among the main controller 161, the charge/discharge determination unit 220 includes an AC/DC controller 163 and a DC/DC that control the AC/DC converter 130 and the plurality of DC/DC converters 150, respectively. Arranged adjacent to the controller 164, the payment unit 240 and the reservation management unit 250 may be implemented in a computer device connected through a communication network such as the Internet.

Also, although the memory 162 is also shown as one functional block, it may be implemented as two or more memory devices that are communicatively connected to each other.

The pack management unit 210 may manage states of the battery packs 120 stored in the battery charging station 100 . The pack management unit 210 may check which storage boxes 110 contain the battery packs 120 , detect and store the battery voltage and charging state of each of the battery packs 120 . The pack manager 210 may receive the state of charge and health of the battery pack 120 from the battery manager of the battery pack 120 .

For example, when a discharged battery pack 120c is stored in an empty storage box 110e, the pack management unit 210 checks the identification number of the storage box 110 in which the battery pack 120c is stored, and the battery pack ( The battery voltage of 120c) may be measured, and the state of charge of the battery pack 120c may be obtained. The pack management unit 210 may estimate the state of charge based on the battery voltage of the battery pack 120c or may receive the state of charge from the battery management unit of the battery pack 120c.

The charge/discharge determination unit 220 is based on the number of battery packs 120 detected by the pack management unit 210 and each state of charge, current time, power rate data 260, and demand prediction model 280. Charging and discharging of each of the battery packs 120 stored in the boxes 110 may be determined based on the determined exchange demand prediction value.

For example, the charge/discharge determiner 220 may determine to charge all of the battery packs 120 during late night hours when electricity rates are low. According to one example, the charge/discharge determining unit 220 only charges the state of charge of the battery packs 120 up to 80% from the reference time to a preset time so that all of the battery packs 120 are fully charged at the reference time when the power rate rises. And, after a preset time elapses, the state of charge of the battery packs 120 may be charged up to 100%. Deterioration of the battery pack 120 may be delayed by reducing the time when the state of charge of the battery pack 120 is 100%.

According to another example, the charge/discharge determiner 220 may determine to charge at least some of the charged battery packs 120b when the number of fully charged battery packs 120a is less than the predicted replacement demand. At this time, the charge/discharge determining unit 220 may charge the charged battery packs 120b using the power of the AC power source 10 according to the power rate time zone, and may charge at least some battery packs among the battery packs 120b. In order to fully charge, the remaining power of the remaining charged battery packs 120b may be used.

The model updater 230 may update the demand prediction model 280 by reflecting the newly added usage history data. As the battery charging station 100 is used, battery packs are exchanged, and details of such exchange may be stored in usage history data. Usage history data is added over time, and the model updater 230 may perform statistical processing including the newly added usage history data, and update the demand prediction model 280 based on the statistical processing.

The model updating unit 230 may statistically process usage history data for each season and each day of the week in order to increase the accuracy of statistics. The model updating unit 230 may also perform statistical processing for assigning weights to data close to the current point in time.

The payment unit 240 may provide a user interface through which a user may charge and pay a fee for exchanging the discharged battery pack 120c with a fully charged battery pack 120a. A user interface provided by the payment unit 240 may be displayed on a display device mounted in the battery charging station 100 . According to another example, a user may access the payment unit 240 of the battery charging station 100 through the Internet and proceed with payment through a user interface provided by the payment unit 240 .

The user may make a reservation to exchange the discharged battery pack 120c with a fully charged battery pack 120a through the reservation management unit 250 . The reservation management unit 250 may manage a user's battery pack replacement reservation. The reservation management unit 250 may manage the reserved battery pack exchange quantity and exchange time. The charge/discharge determiner 220 may calculate a battery pack demand estimate by reflecting reservation details.

The power rate data 260 includes information about power rates for each time period. Depending on the season, hourly electricity rates may vary. In addition, electricity rates may vary from moment to moment depending on power supply and demand. An example of power rate data 260 is shown in FIG. 4 .

The use history data 270 includes information about a history of a user exchanging a battery pack. The date and time when the user replaced the battery pack are stored in the usage history data 270 . The model updating unit 230 may statistically process date and time data when the user replaces the battery pack and store the data as usage history data 270 . Usage history data 270 generated by statistically processing exchange date and time data is shown in FIG. 5 as an example.

The demand forecasting model 280 is generated using the usage history data 270 , and may be generated by, for example, the model updating unit 230 . The demand prediction model 280 may output the predicted value of the replacement quantity of battery packs from the current time to the reference time and the upper and lower limit values of the confidence interval of the predicted replacement quantity. The acceptance predictive model 280 is illustratively described with reference to FIG. 6 .

The reference time may be set based on a power rate change time that changes from a time period with high power rates to a time period with low power rates. The power rate change time may be a time of changing from a peak load time zone to a medium load time zone or a light load time zone, or a time changing from a medium load time zone to a light load time zone. The reference time can be several times a day. For example, referring to the power rate data of FIG. 4, the reference time is set based on 12:00, 17:00, and 23:00 in spring, summer, and autumn, and the reference time is set based on 12:00, 20:00, and 23:00. can

The reference time may be set to a point in time when a charging time required to fully charge the battery pack 120c that has been discharged at the power rate change time has passed. The battery charging station 100 can fully charge the discharged battery pack 120c by charging it from the power rate change time to the reference time.

4 shows an example of power rate data 260 according to one embodiment of the present invention.

Referring to FIG. 4 , electricity rates for each time period may vary according to a light load time period, a medium load time period, and a peak load time period. Electricity rates are highest during peak load times and lowest during light load times. The light load time period may be a late night time period.

As shown in FIG. 4 , power rates for each time zone may be different for each season. The light load period is 23:00 to 9:00, the peak load period is 10:00 to 12:00 and 17:00 to 23:00 in spring, summer and autumn, and 10:00 to 12:00 and 17:00 to 20:00 in winter. hour, from 22:00 to 23:00.

Electricity rates during peak load times may be several times higher than those during light load times. For example, the power rate during the peak load time period may be twice or more than the power rate during the light load time period.

5 illustrates an example of use history data 270 generated by statistically processing the history of users using the battery charging station 100 according to an embodiment of the present invention.

Referring to FIG. 5 , a bar (B) showing an average (M) of the number of exchanges and a confidence interval for each time period is shown. The bar (B) may indicate the upper limit value (H) and the lower limit value (L) of the exchange count confidence interval. The graph shown in FIG. 5 is provided for understanding, and the usage history data 270 includes the average (M) of the number of exchanges for each time period and the upper limit value (H) and lower limit value (L) of the confidence interval. The mean (M) of the number of exchanges and the upper bound (H) and lower bound (L) of the confidence interval are referred to as exchange number data.

Although exchange number data is stored in units of one hour in FIG. 5 , this is exemplary, and exchange number data may be stored in units of 30 minutes or 10 minutes. Exchange frequency data may be generated for each season and each day of the week.

An average and a standard deviation of the number of exchanges may be calculated based on the time at which the user exchanges the battery pack in the battery charging station 100 . A confidence interval of the number of exchanges may be determined based on the mean and standard deviation of the number of exchanges. The confidence interval of the number of exchanges is an interval in which the possibility of battery pack replacement in a corresponding time period is a preset probability. For example, when the average number of exchanges in a corresponding time zone is 10, there may be a 90% probability that the actual number of exchanges is 7 or more and 13 or less. At this time, the upper limit value (H) of the confidence interval is 13, and the lower limit value (L) is 7.

As shown in FIG. 5 , the number of battery pack replacements is low at midnight, and the number of battery pack replacements is relatively high during lunch and dinner.

6 is a diagram for explaining a demand prediction model 280 according to the present invention.

Referring to FIG. 6 , an upper limit value (HL) and a lower limit value (LL) of a confidence interval of the prediction value ML of the replacement quantity of the battery pack 120 and the prediction value of the replacement quantity from the current time to the reference time Tref are shown. do. Since the exchange quantity prediction value (ML), upper limit value (HL), and lower limit value (LL) vary with time, they are indicated by lines in FIG. 6 . In the graph of FIG. 6, the horizontal axis represents time, and the vertical axis represents the exchange quantity.

In FIG. 6, T2 is a power rate change time at which the power rate becomes cheaper. From T1 to T2 is the high load time period, and from T2 to T3 is the low load time period. TC is a charging time required to fully charge the discharged battery packs 120c, and the reference time Tref may be set based on the power rate change time T2 and the charging time TC.

The demand prediction model 280 may provide an exchange quantity prediction value (ML), an upper limit value (HL), and a lower limit value (LL) corresponding to the current time before the power price change time T2. After the power price change time (T2), the exchange quantity prediction value (ML), upper limit value (HL), and lower limit value (LL) calculated based on the reference time set based on the subsequent power rate change time are provided. It can be.

In FIG. 6 , the first to fourth regions Ra, Rb, Rc, and Rd are based on the prediction value ML of the exchange quantity, the upper limit value HL, and the lower limit value LL before the power rate change time T2. ) can be divided into four areas such as The first area Ra is an area where the number of fully charged battery packs 120a currently possessed is greater than the upper limit value HL. The second area Rb is an area in which the number of fully charged battery packs 120a currently possessed is between the upper limit value HL and the replacement amount prediction value ML. The third area Rc is an area in which the number of fully charged battery packs 120a currently possessed is between the replacement quantity prediction value ML and the lower limit value LL. The fourth area Rd is an area where the number of fully charged battery packs 120a currently possessed is less than the lower limit value LL.

The charge/discharge determining unit 220 of FIG. 3 determines which region among the first to fourth regions Ra, Rb, Rc, and Rd the number of fully charged battery packs 120a currently possessed is located. Charging and discharging of each of the battery packs 120 may be determined.

According to an example, when the number of fully charged battery packs 120a currently possessed is located in the first area Ra, that is, the number of fully charged battery packs 120a currently possessed is greater than the upper limit value HL. In a large case, power stored in one of the fully charged battery packs 120a may be output to the AC power supply 10 to sell power. This is a case in which the fully charged battery pack 120a remains more than necessary because the actual demand for replacement of the battery pack is small during the high-load period, and the power stored in the battery pack 120a is sold to the outside before the low-load period. can do. According to another example, the first area Ra may be defined as an area larger than a value obtained by adding 1 to the upper limit value HL.

According to an example, when the number of fully charged battery packs 120a currently possessed is located in the second region Rb, that is, the number of fully charged battery packs 120a currently possessed is equal to the upper limit value HL. When it is within the predicted replacement quantity ML, the battery packs 120 stored in the battery charging station 100 may be maintained as they are. That is, the battery packs 120 may not be discharged even though they are charged.

According to an example, when the number of fully charged battery packs 120a currently possessed is located in the third area Rc or the fourth area Rd, that is, the number of fully charged battery packs 120a currently possessed. When is less than the replacement amount predicted value ML, one fully charged battery pack 120a can be made by collecting the electric power stored in the charged battery packs 120b stored in the battery charging station 100 into one battery pack. there is. Some of the charged battery packs 120b are discharged and the other is charged, thereby making one fully charged battery pack 120a. In this case, although power loss occurs due to power conversion efficiency, the operating efficiency of the battery charging station 100 can be improved because it is not necessary to purchase power at a power rate during a high load time period.

According to an example, when the number of fully charged battery packs 120a currently possessed is located in the third area Rc or the fourth area Rd, that is, the number of fully charged battery packs 120a currently possessed. If is less than the lower limit value LL, since it is very likely that the fully charged battery packs 120a currently possessed will be insufficient, the insufficient number of battery packs 120b can be charged using the AC power source 10. there is. The insufficient quantity may be a difference between the number of fully charged battery packs 120a currently possessed and an exchange quantity prediction value (ML).

When the number of fully charged battery packs 120a currently possessed is located in the third region Rc, the power stored in the firstly charged battery packs 120b is collected in one battery pack to form one fully charged battery pack. When one fully charged battery pack 120a cannot be made with the powers stored in the battery packs 120b that have been charged and made 120a, the battery pack 120b can be fully charged using the power of the AC power source 10. there is.

When the number of fully charged battery packs 120a currently possessed is located in the fourth region Rd, the power of the AC power source 10 is used regardless of the powers stored in the charged battery packs 120b to provide battery power. The pack 120b may be cushioned. In this case, the battery pack 120b having the highest state of charge of the charged battery packs 120b may be preferentially fully charged.

A method of operating the battery charging station 100 will be described below with reference to FIGS. 7 and 8 .

7 is a diagram for explaining an exemplary operation of the battery charging station 100 according to the present invention.

Referring to FIG. 7 , the exchange quantity prediction value ML, the upper limit value HL, and the lower limit value LL are the same as those shown in FIG. 6 . P denotes the number of fully charged battery packs 120a currently possessed. When the user's battery pack is replaced (eg), the number of fully charged battery packs 120a decreases as shown in FIG. 7 .

When the quantity P of the currently held fully charged battery packs 120a is smaller than the expected replacement quantity ML, the power stored in the charged battery packs 120b stored in the battery charging station 100 is converted into one battery. By collecting the battery packs, one fully charged battery pack 120a may be generated (chg1).

If one fully charged battery pack 120a cannot be generated with the power stored in the charged battery packs 120b, one battery pack 120b can be fully charged (chg2) using the power of the external power source 10. there is.

After the power rate change time T2 has elapsed, a low load period in which power rates are relatively low begins. Even after the power rate change time T2, each of the battery packs 120 may be charged and discharged according to the exchange quantity prediction value ML, the upper limit value HL, and the lower limit value LL until the next reference time. In this example, all of the battery packs 120 may be charged using the power of the AC power source 10 . Since power remains in the battery packs 120, charging may be performed prior to the reference time Tref.

8 is a diagram for explaining another exemplary operation of the battery charging station 100 according to the present invention.

Referring to FIG. 8 , the exchange quantity prediction value ML, the upper limit value HL, and the lower limit value LL are the same as those shown in FIG. 6 . P denotes the number of fully charged battery packs 120a currently possessed. When the quantity P of fully charged battery packs 120a currently possessed is greater than the upper limit value HL, power stored in the fully charged battery pack 120a is output to the AC power supply 10 to sell power. can When the user's battery pack is exchanged (ex), as shown in FIG. 8, the quantity of fully charged battery packs 120a decreases, and the quantity P of fully charged battery packs 120a currently owned is the upper limit. value (HL). However, as time elapses, the exchange quantity prediction value ML, upper limit value HL, and lower limit value LL become smaller and smaller until the reference time Tref, so that the number of fully charged battery packs 120a currently possessed (P) may be greater than the upper limit value HL, and the electric power stored in the fully charged battery pack 120a may be output to the AC power supply 10, thereby selling the electric power.

When the power rate change time T2 passes, a low load period in which the power rate is relatively low begins, and the battery packs 120 can be charged using the power of the AC power source 10 at a relatively low power cost.

9 shows an example of charging the battery pack of the battery charging station 100 according to the present invention.

Referring to FIG. 9 , the first battery pack 120b1 and the second battery pack 120b2 are battery packs with remaining power. The power stored in the second battery pack 120b2 may be greater than the power stored in the first battery pack 120b1.

The first DC/DC converter 150a connected to the first battery pack 120b1 transfers the power stored in the first battery pack 120b1 to the DC link capacitor 140, and the first connected to the second battery pack 120b2. The 2 DC/DC converter 150b may transfer power stored in the DC link capacitor 140 to the second battery pack 120b2. The first DC/DC converter 150a operates in the reverse direction to discharge the first battery pack 120b1, and the second DC/DC converter 150b operates in the forward direction to charge the second battery pack 120b2. can do.

Accordingly, the power stored in the first battery pack 120b1 decreases to become a battery pack 120d having a low state of charge, and the second battery pack 120b2 becomes a fully charged battery pack 120a.

As described above, in the operation of generating one fully charged battery pack by transferring power between the first and second battery packs 120b1 and 120b2, the quantity P of the currently held fully charged battery packs 120a is exchanged. It may be performed when it is smaller than the quantity predicted value (ML).

10 shows an example of an AC/DC converter of the battery charging station 100 according to the present invention.

Referring to FIG. 10, the AC/DC converter 130 is connected to a three-phase grid through a fuse and includes first to sixth switching elements S1 to S6 constituting a full bridge. can The first to sixth switching elements S1 to S6 may be controlled by a PWM control signal output from the AC/DC controller 163 . The AC/DC converter 130 may operate as a rectifier circuit or an inverter circuit according to a PWM control signal. Each of the first to sixth switching elements S1 to S6 includes a switch and a diode connected in parallel with each other.

A switch unit including a main switch, a precharge switch, and a precharge resistor may be disposed between the three-phase grid and the first to sixth switching devices S1 to S6. Three main switches (main SW) may be disposed for each phase of the grid (Grid).

An LC filter and a current sensor may be disposed for each phase between the switch unit and the first to sixth switching elements S1 to S6. The AC/DC controller 163 may detect an AC current (Iac) between the three-phase grid and the AC/DC converter 130 using a current sensor. The AC/DC controller 163 may detect the AC voltage Vac of the three-phase grid.

The DC output terminal of the AC/DC converter 130 is connected to the DC link capacitor Cdc, and the AC/DC controller 163 can detect the DC link voltage Vdc.

The DC link capacitor Cdc is connected to the first and second terminals T1 and T2, and DC switches DC_SW are provided between the DC link capacitor Cdc and the first and second terminals T1 and T2, respectively. can be placed. The direct current switches (DC_SW) may be controlled by the AC/DC controller 163. A plurality of DC/DC converters 150 may be connected to the first and second terminals T1 and T2.

11 shows an example of a DC/DC converter of the battery charging station 100 according to the present invention.

Referring to FIG. 11 , the DC/DC converter 150 is connected between the first and second terminals T1 and T2 of FIG. 10 and the battery pack 120 . As shown in FIG. 10, a DC link capacitor Cdc is connected between the first and second terminals T1 and T2.

The DC/DC converter 150 includes primary-side switching elements Q1-Q4 constituting the full bridge, secondary-side switching elements Q5-Q8 constituting the full bridge, and primary-side switching elements Q1-Q4. Q4) and a transformer (T1) between the secondary side switching elements (Q5-Q8).

The primary side switching elements Q1 - Q4 may be controlled by the first PWM control signal of the DC/DC controller 164 . The secondary-side switching elements Q5 - Q8 may be controlled by the second PWM control signal of the DC/DC controller 164 . A power delivery direction of the DC/DC converter 150 may be controlled by adjusting the duty ratio of each of the first and second PWM control signals.

An LC circuit composed of an output inductor (Lo) and an output capacitor (Co) may be connected to the secondary side of the DC/DC converter 150. The output capacitor Co is connected in parallel with the battery pack 120 , and battery switches BAT_SW may be connected between the output capacitor Co and the battery pack 120 . The battery switches BAT_SW may be controlled by the DC/DC controller 164 .

As such, the present invention has been described with reference to various embodiments shown in the drawings, but this is only exemplary, and those skilled in the art will understand that various modifications and variations of the embodiments are possible therefrom. . Therefore, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.

Claims (10)

a plurality of holders each capable of accommodating a plurality of battery packs;
a DC link capacitor for storing a DC link voltage;
an AC/DC converter that converts an AC voltage of an AC power supply into a DC voltage and outputs the DC link capacitor to a DC voltage, and converts the DC link voltage into an AC voltage and outputs the converted AC voltage to the AC power supply;
A plurality of batteries for converting the DC link voltage into a battery voltage and outputting the DC link voltage to a corresponding battery pack among the plurality of battery packs, and converting the battery voltage of the corresponding battery pack into the DC link voltage and outputting the DC link voltage to the DC link capacitor. DC/DC converter; and
The plurality of battery packs stored in the plurality of drawers are managed, and based on a demand prediction model generated by statistically processing usage history data including an average and standard deviation of the number of replacements for each time period and a power rate for each time period, the plurality of battery packs are stored in the plurality of storage boxes. A control unit configured to determine charging and discharging of each battery pack and control the AC / DC converter and the plurality of DC / DC converters according to the charging and discharging determination,
The control unit,
a memory for storing the use history data obtained by statistically processing battery pack replacement times, electricity rate data for storing power rates for each time period, and the demand prediction model; and
A main controller configured to determine charging and discharging of each of the plurality of battery packs based on a state of charge of each of the plurality of battery packs stored in the plurality of storage boxes and data stored in the memory;
The demand prediction model is generated using the usage history data, and is configured to output a predicted value of the replacement quantity of battery packs from a current time to a reference time and an upper limit value and a lower limit value of a confidence interval of the predicted replacement quantity of the battery pack. station. delete delete The method of claim 1,
The reference time is set based on a time of changing from a peak load time zone to a medium load time zone or a light load time zone, and a time changing from a middle load time zone to a light load time zone. The method of claim 1,
The control unit outputs power stored in one of the fully charged battery packs to the AC power source when the number of currently fully charged battery packs is greater than the upper limit value during a peak load time period in which electricity rates for each time period are high, and the AC/DC converter and A battery charging station controlling a DC/DC converter connected to the one battery pack. The method of claim 1,
If the number of currently fully charged battery packs is less than the replacement quantity predicted value, the control unit collects power remaining in an unfulfilled battery pack from among the plurality of battery packs to fully charge the AC/DC converter to fully charge one battery pack. and a battery charging station controlling the plurality of DC/DC converters. The method of claim 1,
When the number of battery packs that are currently fully charged is less than the lower limit, the control unit may charge at least one of the plurality of batteries using the power of the AC power regardless of the current time to charge the AC/DC converter and the plurality of batteries. A battery charging station that controls a DC/DC converter. delete The method of claim 1,
wherein the control unit includes a model updating unit configured to update the demand prediction model by reflecting the added usage history data when usage history data is added. The method of claim 1,
The control unit,
an AC/DC controller controlling the AC/DC converter using a PWM control signal; and
A battery charging station including a DC/DC controller controlling the plurality of DC/DC converters using a PWM control signal.

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