Grid stabilization device for electric vehicle charger

Abstract

A grid stabilization device of the present invention may comprise: a charging cable which connects an electric vehicle and a charger; a power measurement unit which collects power data of a power grid; a charger communication control module which is connected, through communication, to an electric vehicle communication control module for controlling communication between the inside of the electric vehicle and the charger for fast or slow charging and exchanges data therewith; and a grid protection unit that takes a grid protection measure against instability generated when power is transmitted between the power grid and a distributed load including the electric vehicle and the charger, wherein when power conversion of a power conversion unit mounted on the electric vehicle does not normally operate, the grid protection unit may command the electric vehicle or the charger to stop discharging or reverse transmission so that instability does not occur in the power grid.

Description

Grid stabilization device for electric vehicle chargers

[0001] The present invention relates to a system stabilization device for an electric vehicle charger that determines whether to reversely transfer distributed loads including an electric vehicle charger or to stop discharging from an electric vehicle to a charger when transferring power between an electric vehicle charger and a power system for V2G.

[0002] [Task information]

[0003] [Project ID] 1415169323

[0004] [Assignment Number] 20202020800020

[0005] Ministry of Trade, Industry and Energy

[0006] [Name of project management (specialized) organization] Korea Institute of Energy Technology Evaluation and Planning

[0007] [Research Project Name] Energy Technology Development Project

[0008] [Research Project Name] Development and Demonstration of a Robot-Based Rapid Automatic Charging System for Electric Vehicles

[0009] [Contribution rate] 1 / 1

[0010] [Name of Host Organization] SK Signet Co., Ltd.

[0011] Research Period: July 1, 2023 - June 30, 2024

[0012] V2G (Vehicle-to-Grid) connects rechargeable eco-friendly vehicles, including EVs and PHEVs, to the power grid. Breaking away from the traditional one-way power supply method of supplying power from the upper grid to the lower grid, V2G allows the lower grid to supply power to the upper grid, thereby utilizing idle power in distributed loads. In other words, electric vehicles can function as portable energy storage systems (ESS).

[0013] Electric vehicle chargers can be categorized into DC chargers, which directly convert the electric vehicle's DC power into AC power, a system component, and AC chargers, which perform the power conversion within the electric vehicle. In particular, AC chargers utilize a bidirectional power converter built into the electric vehicle, such as an onboard charger (OBC), to perform the power conversion. Therefore, AC chargers are more vulnerable to grid instability than DC chargers, or to instability within the distributed load, including the electric vehicle and the charger.

[0014] The present invention relates to a system stabilization device including a system protection unit that detects or manages instability factors occurring during power transmission between an electric vehicle charger, a distributed load such as an electric vehicle, and a power system, thereby stabilizing the system.

[0015] The system stabilization device of the present invention may include a charging cable connecting an electric vehicle and a charger, a power measurement unit collecting power data of a power system, an electric vehicle communication control module that controls communication between the inside of the electric vehicle and the charger for rapid or slow charging and a charger communication control module that is communicatively connected to exchange data, and a system protection unit that takes system protection measures against instability occurring during power transmission between a distributed load including the electric vehicle and the charger and the power system, and when power conversion of a power conversion unit mounted on the electric vehicle does not operate normally, the system protection unit may command the electric vehicle or the charger to stop discharging or stop reverse transmission so as to prevent instability from occurring in the power system.

[0016] The present invention detects or manages an instability factor occurring during power transmission between a distributed load including an electric vehicle charger including an AC charger and an electric vehicle including an OBC, and a power system, thereby promoting system stabilization.

[0017] The system protection unit of the present invention can perform a safety function to prevent power system imbalance from occurring even when the electric vehicle fails to perform the power conversion function normally.

[0018] The system protection unit of the present invention compares power reference data including a required power value transmitted between an electric vehicle communication control module and a charger communication control module with measurement data collected by a power measurement unit, and if a difference exceeding a predetermined range occurs, the system protection unit can protect the power system by stopping the discharge function.

[0019] The system protection unit of the present invention can protect the system by stopping discharge when the system data including the system information value transmitted from the charger communication control module to the electric vehicle communication control module differs by a certain range or more from the power quality status of the measured power data of the actual power system.

[0020] The system protection unit of the present invention can protect the system by stopping discharge when power data including power status (frequency, phase, voltage, etc.) measured at both ends of the charging cable and the power system is outside a certain range.

[0021] The system protection unit of the present invention can protect the system by stopping discharge when the change value of power data indicating the power quality of the power system and the charger cable terminal differs significantly by a certain level or more.

[0022] Figure 1 is a relationship diagram between an electric vehicle, an electric vehicle charger, and a power system of the present invention.

[0023] Figure 2 is an explanatory diagram of components of the system stabilization device of the present invention.

[0024] Figure 3 is a schematic diagram of the system stabilization method of the present invention.

[0025] Figure 4 is a data flow diagram based on the system protection unit of the present invention.

[0026] FIG. 5 is a diagram illustrating an extended system protection unit provided in a charging station equipped with multiple electric vehicles and chargers of the present invention.

[0027] Figures 6 to 9 are explanatory diagrams of the analysis steps of the present invention.

[0028] Figure 10 is an explanatory diagram for a change in a group of a given charger according to a change in the group center value in the charger management step of the present invention.

[0029] Hereinafter, with reference to FIGS. 1 to 10, the system stabilization device and system stabilization method of the present invention will be described.

[0030] The distributed load (80) not only receives power from the power system (10), but can also transmit idle power back to the power system (10). An electric vehicle (100) or an electric vehicle charger (200) may be included in the distributed load (80). In this case, the electric vehicle may function as a mobile energy storage system (ESS).

[0031] According to FIG. 1, the charger (200) can store power received from the power system (10) in the power supply unit (210) or transmit it back to the electric vehicle (100) to charge it. In addition, the charger (200) can discharge power stored in the battery (130) of the electric vehicle (100) to the charger (200) or transmit power stored in the power supply unit (210) back to the power system (10).

[0032] An electric vehicle charger (200) can be divided into a DC charger that directly converts the DC power of an electric vehicle (100) into AC power, which is a system component, and an AC charger that performs power conversion in the electric vehicle (100). In particular, in the case of an AC charger, power conversion can be performed in the electric vehicle (100) using a bidirectional power conversion unit (110) built into the electric vehicle (100), such as an on-board charger (OBC). The DC charger may be for rapid charging at the level of 50 kW to 200 kW, and the AC charger may be for slow charging at the level of 2 kW to 7 kW.

[0033] AC chargers can be charged using portable chargers in outlets in apartment complex parking lots or building parking lots, so they have the advantage of being easy to charge without having to secure a dedicated parking space for the charger.

[0034] In the case of an AC charger, power conversion may be performed in a bidirectional power conversion unit (110) built into the electric vehicle (100), rather than in the charger (200). Here, the bidirectional power conversion unit (110) may include an OBC (On Board Charger). For example, the input / output voltage specifications of the bidirectional power conversion unit (110) may have a range of AC power of 50 V to 300 V on one side and a battery-side voltage of 200 V to 500 V on the other side. For example, the bidirectional power conversion unit (110) may receive AC power from the power supply unit (210) of the charger (200) or the charging equipment (EVSE: Electric Vehicle Supply Equipment) of the electric vehicle, and charge a high-voltage battery (130) through an ICCB (In-Cable Control Box), etc.

[0035] Meanwhile, since the DC charger converts DC to AC in the electric vehicle (100), the system imbalance factor can be very low in the case of discharge or reverse transmission. Compared to the DC charger, the AC charger can be vulnerable to instability factors originating from the power system (10) or from the distributed load (80) including the electric vehicle and the charger.

[0036] That is, since the electric vehicle-mounted power conversion unit (110) is a device that uses AC power in the form of alternating current, it can be greatly affected by the environment of the power system (10) or surrounding facilities. In particular, the power conversion unit (110) installed in the electric vehicle (100) is difficult to have a large capacity due to its installation characteristics, and can only convert relatively low-capacity power, so the impact of surrounding unstable factors can be greater. Factors that make such distributed load (80) unstable may include abnormal charging environments such as poor connection of the charging connector, or unstable factors of the power system (10) that supplies AC input power due to power outages, etc. As a result, the charger customer may not be able to charge, or the charging scheduling may be disrupted due to discharge interruption or reverse transmission interruption.

[0037] The present invention may be a system stabilization device or a system stabilization method that aims to resolve / manage instability resulting from the power conversion unit (110) mounted on the electric vehicle (100) described above. Accordingly, the electric vehicle charger (200) of the present invention may be an AC charger in which a system protection unit (260) is implemented. Accordingly, the charger (200) can perform stabilization functions such as discharging stop or reverse transmission stop so that the power system (10) does not become unstable even when the power conversion unit (110) of the electric vehicle (100) fails to perform the power conversion function normally.

[0038] In FIG. 2, the system stabilization device of the present invention may include at least one of a power supply unit (210), a charger communication control module (220), a power measurement unit (230), a circuit breaker (240), a charging controller (250), and a system protection unit (260).

[0039] The power measurement unit (230) can collect power data (D32) of the charging cable (50) connecting the electric vehicle (100) and the electric vehicle charger (200) and the power system (10).

[0040] The charger communication control module (220) can be connected to the electric vehicle communication control module (170) that controls communication between the interior of the electric vehicle (100) and the electric vehicle charger (200) for rapid or slow charging, and can exchange data.

[0041] The system protection unit (260) can take system protection measures against instability that occurs when power is transmitted between a distributed load (80) including an electric vehicle (100) and an electric vehicle charger (200) and a power system (10).

[0042] According to FIG. 3, the system stabilization method of the present invention may include at least one of a data collection step (S100), a data comparison step (S200), a system protection step (S300), and an analysis step (S400).

[0043] An electric vehicle (100) may include one of an onboard bidirectional power conversion unit (110), a battery (130), a battery control unit (150) (BMS) capable of controlling the battery (130), and an electric vehicle communication control module (170) that exchanges signals or data with a charger (200).

[0044] The electric vehicle communication control module (170) may be an EVCC (Electric Vehicle Communication Controller). The EVCC may control communication between a control device inside the vehicle and a charging infrastructure for rapid and slow charging of the electric vehicle (100), and may be a communication control module capable of controlling charging status such as voltage and current, providing rate information, and performing security authentication functions through communication with a charging infrastructure such as a charger (200) when charging the electric vehicle (100).

[0045] That is, when the charging cable (50) connected to the charger (200) is connected to the electric vehicle (100), the electric vehicle communication control module (170) can detect the PWM signal and initiate communication by sending a signal to the charger communication control module (220) of the charger (200). Here, the charger communication control module (220) may be a SECC (Supply Equipment Communication Controller). Therefore, since the electric vehicle (100) and the charger (200) are electrically connected by the charging cable (50), the electric vehicle communication control module (120) and the charger communication control module (220) can exchange signals or information with each other.

[0046] The charging cable (50) may be a power-line communication (PLC) type. PLC may be a technology that transmits data such as voice by loading it into a frequency signal via a power line that supplies power. Therefore, when connecting a charging cable (50) connected to a charger (200) to an electric vehicle (100), the charging cable (50) exchanges signal or data information through a CP (Control Pilot) signal line according to the electric vehicle charging standard, and a separate power line for power supply may be provided. A charging method using such power line communication may be referred to as a CCS (Combined Charging System) or CCS combo.

[0047] When an electric vehicle (100) and a charging cable (50) are connected, in an electric vehicle (100) that supports CCS charging, the EVCC of the electric vehicle (100) and the SECC of the charger (200) can exchange data through network communication based on TCP / IP. Accordingly, since the electric vehicle (100) and the charger (200) can communicate bidirectionally, the unique identification value of the electric vehicle (100) can be transmitted or extracted from the electric vehicle (100) to the charger (200), and if this unique identification value is registered in advance in the center control unit (300), the registered vehicle can automatically process authentication or authorization without a separate means after registration, thereby increasing user convenience.

[0048] The unique identification value that can be acquired from the electric vehicle (100) may be a MAC address, which is a network-specific value provided by the electric vehicle communication control module (170), or an EVID or EVCCID value exchanged during the charging communication process. The MAC address may be a unique value of a LAN card that is unique worldwide, and since only one MAC address can be assigned to each communication device such as a LAN card or smartphone, the MAC address can be used like a resident registration number on the network. The EVID may be set to the same value depending on the manufacturer of the electric vehicle (100).

[0049] The electrical status such as the charging status, voltage, and current of the battery (130) can be controlled and managed by the battery control unit (150), and the battery control unit (150) can transmit battery-related information such as the remaining capacity (SoC) of the battery (140) by sending the status of the battery (130) to the charger communication control module (220) through the electric vehicle communication control module (120).

[0050] An electric vehicle charger (200) may include a charger communication control module (220) that can exchange signals or data with an electric vehicle communication control module (120) or a server (70), and a power supply unit (210) that can receive power from a power grid (10) and charge a battery (130) of an electric vehicle (100).

[0051] A cable (54) that can exchange signals or data between an electric vehicle communication control module (120) and a charger communication control module (220), and a cable (52) that can exchange power between a power supply unit (240) and a battery (140) can be distinguished. Meanwhile, each cable (52, 54) can be included in a charging cable (50), and by connecting the charging cable (50) to the electric vehicle (100), each cable is also electrically connected to enable bidirectional communication.

[0052] The server (70) can exchange signals or data with the charger communication control module (220). When communication is initiated through an electrical connection between the communication control modules of the electric vehicle (100) and the charger (200), data transmission and reception can also occur between the EVCC (170), SECC (220), and the server (70).

[0053] In the data collection step (S100), the power measurement unit (230) can collect power data (D32) in real time that can identify the power quality status at both ends of the charging cable (50) side and the power system (10) side.

[0054] In the data collection step (S100), the collected data may include reference data (D10) or measurement data (D30). The reference data (D10) may be a reference setting value for the measurement data (D30) collected by the power measurement unit (230), etc. The reference data (D10) may include system data (D12) or specification data (D14), and the measurement data (D30) may include power data (D32). The system data (D12) may include information including voltage, current, frequency, phase, etc. of AC power of the power system (10). The specification data (D14) may include the specifications or specifications of the onboard power conversion unit (110) of the electric vehicle (100), or the specifications or specifications of the charger (200).

[0055] The measurement data (D30) may include power data (D32) that can be compared with the reference data (D10) by the system protection unit (260).

[0056] The charging controller (250) can control the operation of at least one of the power supply unit (210), the charger communication control module (220), the power measurement unit (230), the circuit breaker (250), and the system protection unit (260), and as a result, can determine the charging / discharging schedule including the discharging stop or discharging maintenance of the electric vehicle (100) connected to the charger (200). That is, the charging controller (250) can control at least one system stabilization process among the data collection step (S100) and the management step (S400). That is, the charging controller (250) can schedule the charging of the charger (200) according to the system protection measures including whether to discharge or whether to reversely transmit according to the system protection unit (260).

[0057] In the data collection step (S100), the reference data (D10) or the measurement data (D30) may be transmitted to the system protection unit (260) after being stored in the charging controller (250) or a separate database, or may be transmitted directly to the system protection unit (260).

[0058] That is, the measurement data (D30) is collected by the power measurement unit (230), and is sent from the power measurement unit (230) to the charging controller (250) or a separate database, stored therein, and then transmitted to the system protection unit (260), or can be transmitted directly from the power measurement unit (230) to the system protection unit (260).

[0059] The system data (D12) of the reference data (D10) may be transmitted from the charger communication control module (220) or the server (70) to the charging controller (250) or a separate database, stored therein, and then transmitted to the system protection unit (260), or may be transmitted directly from the charger communication control module (220) or the server (70) to the system protection unit (260).

[0060] Among the specification data (D14) of the reference data (D10), the electric vehicle standard / specification related data may be sent from the electric vehicle communication control module (170) to the charger communication control module (220) or server (70) and stored thereafter transmitted to the system protection unit (260), or may be transmitted directly from the electric vehicle communication control module (170) to the system protection unit (260) via the charger communication control module (220).

[0061] Among the specification data (D14) of the reference data (D10), the charger standard / specification related data can be transmitted to the system protection unit (260) after being stored in the charger communication control module (220) or server (70), or can be transmitted directly from the charger communication control module (220) to the system protection unit (260).

[0062] The system protection unit (260) can receive reference data (D10) or measurement data (D30) from at least one of the power measurement unit (210), the charging controller (250), and the server (70). That is, in the data comparison step (S200), the system protection unit (260) can receive data collected in the data collection step (S100) and compare the reference data (D10) with the measurement data (D30).

[0063] Data including frequency, phase, voltage, current, power, etc. may be referred to as electrical data or power data. If, as a result of the above comparison, a power quality abnormality occurs in the power data or electrical data, the system protection unit (260) may move on to the system protection step (S300) and take action. Here, the power quality abnormality may include measurement data (D30), such as power data (D32), being out of range or exceeding a threshold in terms of frequency, phase, voltage, etc., when compared to the reference data (D10).

[0064] The system protection step (S300) may include a step (S310) of determining whether discharge or reverse transmission is performed by the system protection unit (260), or a step (S330) of transmitting a blocking signal to a charger to stop discharging.

[0065] Step 310 (S310) can be derived as a result of the data comparison step (S200).

[0066] In step S330, if it is determined in step S310 whether to stop discharging or perform reverse transmission, it may be determined which electric vehicle charger (200) in a charging station (90) equipped with multiple electric vehicle chargers (200) to block. In step S330, the system protection unit (260) may transmit a blocking signal to a circuit breaker (240) connected to the electric vehicle charger (200) that has been determined to stop discharging. If the number of chargers (200) blocked by the circuit breaker (240) is single, reverse transmission to the power system (10) will be stopped, and if there are multiple chargers, reverse transmission may be performed to the remaining chargers (200) excluding the charger (200) whose discharging has been stopped.

[0067] Therefore, in the system protection step (S300), the system protection unit (260) can determine whether to discharge from the electric vehicle (100) to the charger (200) or to reversely transmit from the charger (200) to the power system (10). In the case of a charging station (90) equipped with multiple chargers (200), it can determine whether to reversely transmit to the entire charging station (90), and if to reversely transmit, which charger among the chargers (200) will stop discharging and which charger will maintain discharging.

[0068] In this way, the present invention can achieve the purpose of system protection by utilizing a bidirectional power conversion unit (110), an electric vehicle communication control module (170), a charger communication control module (220), a power measurement unit (230), a circuit breaker (240), a charging controller (250), etc., centered around a system protection unit (260). The system protection unit (260), charger communication control module (220), power measurement unit (230), circuit breaker (240), charging controller (250), etc., can be included in a charger (200) or a server (70).

[0069] Figure 4 summarizes the data flow, such as transmission or exchange of main data for system protection of the present invention.

[0070] A system protection measure such as discharge stop or reverse transmission stop is taken by the system protection unit (260), and in the case of discharge stop, the system protection unit (260) can transmit a blocking signal to the circuit breaker (240) corresponding to the electric vehicle (100) or charger (200) for which discharge stop has been determined (1030).

[0071] In order to decide on protective measures such as discharge interruption, data comparison (S200) is required, and the system protection unit (260) can receive information required for data comparison (S200) from the power measurement unit (230), the charger communication control module (220), or the server (70). The power measurement unit (230) can transmit measurement data (D30) including power data (D32) to the system protection unit (260) (1010). The charger communication control module (220) or the server (70) can transmit reference data (D10) including system data (D12) or specification data (D14) to the system protection unit (260) (1020, 1025). Here, specification data (D14) including standard / specification data or power conversion data of the onboard bidirectional power conversion unit (110) of the electric vehicle (100) may be transmitted from the electric vehicle communication control module (170) to the charger communication control module (220) or server (70) (1015), and then transmitted again to the system protection unit (260).

[0072] The system protection measures by the system protection unit (260) are summarized.

[0073] The system protection unit (260) can detect or manage instability factors occurring during power transmission between distributed loads (80) and the power system (10), and as a result, can promote system stabilization. Here, the distributed load (80) can include an electric vehicle charger (200) including an AC charger, and an electric vehicle equipped with a vehicle-mounted power conversion unit (110) such as an OBC.

[0074] The system protection unit (260) can perform a safety function to prevent imbalance or instability from occurring in the power system (10) even when the power conversion unit (110) of the electric vehicle (100) fails to perform the power conversion function normally.

[0075] The system protection unit (260) compares the reference data (D10) including the required power value transmitted between the electric vehicle communication control module (170) and the charger communication control module (220) with the measurement data (D30) collected by the power measurement unit (230), and if a difference exceeding a predetermined range occurs, the system protection unit (260) can protect the power system (10) by stopping the discharge function of the electric vehicle (100) or the charger (200). The stopping of the discharge of the electric vehicle (100) or the charger (200) can include stopping the discharge from the electric vehicle (100) to the charger (200), or stopping the reverse transmission from the charger (200) to the power system (10).

[0076] The system protection unit (260) can protect the system (10) by stopping the discharge of the electric vehicle (100) or the charger (200) when the system data (D12) including the system information value transmitted from the charger communication control module (220) to the electric vehicle communication control module (170) differs by a certain range or more from the power quality status of the measured power data (D30, D32) of the actual power system (10).

[0077] The system protection unit (260) can protect the system (10) by stopping the discharge of the electric vehicle (100) or the charger (200) when the power data (D32) including the power status (frequency, phase, voltage, etc.) measured at both ends of the charging cable (50) and the power system (10) is outside a certain range.

[0078] The system protection unit (260) can protect the system (10) by stopping the discharge of the electric vehicle (100) or the charger (200) when the change value of the power data (D32) indicating the power quality of the power system (10) and the charger cable end (50) differs significantly by a certain level or more.

[0079] The main purpose of this system protection measure by the system protection unit (260) is to protect the system (10) from instability factors caused by power conversion by the power conversion unit (110) at the electric vehicle (100) level, but it can also reduce damage to the electric vehicle (100) or charger (200) caused by factors that destabilize the system, which can ultimately be beneficial to electric vehicle users or charger business / managers.

[0080] In addition, the charger business / management side can manage the quality of the charger, including predicting the lifespan of the charger (200), such as replacement and repair, through the analysis step (S400).

[0081] That is, the analysis step (S400) is a post-step of system protection, and may be used to predict / manage the life of the charger (200) by using parameters including the discharge interruption frequency of each charger (200) and the total accumulated amount of discharge interruption, by the system protection step (S300).

[0082] The analysis step (S400) may include a charger management step (S410) or a correlation derivation step (S430) between a vehicle-mounted power conversion unit (110) such as an OBC and a charger (200).

[0083] In particular, the charger management step (S410) may be more effective when a charging station (90) is provided with multiple chargers (200) or when multiple charging stations (90) are operated.

[0084] As shown in FIG. 5, multiple chargers (200) equipped with power supply units (210) for supplying power to electric vehicles (100) may be installed in a parking area. A charging station (90) capable of collecting and managing data or signals from multiple chargers (200) as charging spots may be provided. Here, the distributed load (80) may include multiple chargers (200) corresponding to multiple electric vehicles (100) parked for charging.

[0085] In this case, the system stabilization device of the present invention may include a center distribution module (300) whose first end is connected to a plurality of chargers (200) and whose other end is connected to a power system (10).

[0086] The center distribution module (300) may include at least one of an extended system protection unit (310) (or system protection unit (260)), a center communication unit (330), and an energy storage unit (ESS) (350).

[0087] The extended system protection unit (310) can manage the system protection measures for the entire charging station (90) separately from the system protection unit (260) installed in each charger (200). If the system protection unit (260) is individually installed in each charger (200), the extended system protection unit (310) can transmit the individually determined protection measures, such as discharge stop, to each system protection unit (260). On the other hand, if the system protection unit (260) is not installed in each charger (200) and only the extended system protection unit (310) is equipped, after the extended system protection unit (310) determines the system protection measures, it can issue a command, such as discharge stop, to the charging controller (250), charger communication control module (220), or circuit breaker (240) of each charger (200).

[0088] For example, in a charging station (90) equipped with three or more chargers (200), when an electric vehicle equipped with a first power conversion unit (111) is connected to a first charger (201) for charging, an electric vehicle equipped with a second power conversion unit (112) is connected to a second charger (202) for charging, and an electric vehicle equipped with a third power conversion unit (113) is connected to a third charger (203) for charging, the extended system protection unit (310) may, in the data comparison step (S200) or the system protection step (S300), issue a discharge stop command to the first power conversion unit (111) (or the first charger (201)) and the third power conversion unit (113) (or the third charger (203)), and may determine or issue a command to discharge or maintain discharge to the second power conversion unit (112) (or the second charger (202)).

[0089] In this way, quality control (S410) of the charger (200) can be performed based on the frequency of protective measures such as discharge interruption applied to multiple chargers (200) or the total accumulated amount of discharge interruption.

[0090] Using FIGS. 6 to 19, the charger management step (S410) is described as a specific example.

[0091] For systematic charger management, grouping can be performed based on parameters related to the charger's lifespan. These parameters may include discharge interruption frequency or total accumulated discharge interruption amount. The types and number of parameters may vary or be expanded, but the charger management step (S410) described in this specification can be similarly expanded and applied. Accordingly, the following description focuses on two parameters related to the charger's lifespan, discharge interruption frequency or total accumulated discharge interruption amount. However, if three or more parameters are selected, the two-dimensional description of FIG. 9 can be similarly expanded and applied to three or more dimensions.

[0092] In Fig. 6, parameter values ​​of discharge interruption frequency and discharge interruption cumulative total amount are given for each charger. The parameter values ​​(discharge interruption frequency, discharge interruption cumulative total amount) assigned to each charger (200) are stored based on the discharge interruption command issued by the system protection unit (260) or the extended system protection unit (310), and can be utilized in the analysis step (S400) by the system protection unit (260). That is, this is the case where the discharge interruption frequency is selected as the first parameter, and the discharge interruption cumulative total amount is selected as the second parameter.

[0093] Fig. 7 (a) shows that three are selected as the initial central values ​​of each group. The number of groups is 3 for example, but if the number of groups is two or more, the discussions can be similarly applied. The number of groups can be appropriately determined according to the parameter value distribution of Fig. 6. In order to determine the appropriate number of groups, when calculating the distance between groups, the sum of the variances of the parameter values ​​of the chargers can be used as a standard. That is, the appropriate number of groups can be determined by determining the distance between groups based on the degree of separation from the average of each charger (200) belonging to the two groups, i.e., the square of the deviation, summed across all members.

[0094] In (b) of Fig. 7, the total number of chargers (200) is selected as 10, and each charger (200) can belong to any one of the first charger group (G1), the second charger group (G2), and the third charger group (G3) depending on the distance from the three initial group centers (GC0) of (a).

[0095] Here, the distance from the initial group center (GC0) of each charger (200) may include a Euclidean distance or a squared Euclidean distance. The Euclidean distance may refer to the Pythagorean distance between each charger (200) and the initial group center (GC0) based on parameter values ​​(discharge interruption frequency, total accumulated discharge interruption amount) assigned to each charger (200). The squared Euclidean distance may refer to the square of the Euclidean distance.

[0096] According to (a) of Fig. 7, each charger (200) can be displayed as (first parameter value, second parameter value).

[0097] The group center initial value (GC0) may be such that the first charger group (G1) may be selected as the first charger (first parameter 23, second parameter 57), the second charger group (G2) may be selected as the fourth charger (40, 88), and the third charger group (G3) may be selected as the third charger (57, 76). Depending on the distance from the initial group center (GC0), the first charger group (G1) may include the first charger and the ninth charger, the second charger group (G2) may include the second charger, the fourth charger, the fifth charger, the sixth charger, and the tenth charger, and the third charger group (G3) may include the third charger, the seventh charger, and the eighth charger.

[0098] Figure 8 (a) shows the final group center (GCf), and Figure 8 (b) shows the number of chargers belonging to the group. The table in Figure 9 shows the grouping results.

[0099] According to FIGS. 8 and 9, the final group center (GCf) may have different center values ​​depending on the distribution of chargers belonging to each group. For example, the center value of the discharge interruption frequency of the first and ninth chargers belonging to the first charger group (G1) is 27.5 (=(23+32) / 2), which is rounded to 28. The center value may be expressed as (first parameter value, second parameter value). The center value of the first charger group (G1) may be (28,61), and the center value of the third charger group (G3) may be (54,79).

[0100] From this result, the first charger group (G1) has a low discharge interruption frequency and a low cumulative discharge interruption amount, so it may not require many replacements or repairs, and can be classified into upper, middle, and lower middle groups in terms of charger lifespan prediction.

[0101] The second charger group (G2) may be the group with the highest cumulative total amount of discharge interruptions, and the third charger group (G3) may be the group with the highest frequency of discharge interruptions. Depending on which parameter is used to classify the lifespan into upper, middle, and lower grades, the resulting grades may differ. In one embodiment, although the parameters of the second charger group (G2) and the third charger group (G3) are different, if the difference between the parameters is within the set value, the higher the frequency of discharge interruptions, which is the first parameter, the more likely it is that the charger group will require replacement or repair.

[0102] Accordingly, the second charger group (G2) can be classified as a mid-level group, and the third charger group (G3) can be classified as a low-level group, so that the replacement or repair period can be scheduled or provided in the order of the third charger group (G3), the second charger group (G2), and the first charger group (G1) in terms of charger life prediction.

[0103] In summary, the system protection unit (260) can perform charger management including charger life prediction (S410) after system protection measures including discharge interruption, and can group chargers (200) according to parameters related to the life of the chargers for charger management. The initial charger groups (1100, 1200, 1300) and the initial center of the charger groups (1120, 1220, 1320) can be moved by grouping. The charger groups (1102, 1202, 1302) moved by grouping can be distinguished according to the grade in terms of charger life prediction. The system protection unit (260) can provide scheduling for the replacement or repair timing of the charger groups (G1, G2, G3) according to the grade in terms of charger life prediction.

[0104] In addition, the analysis step (S400) or the charger management step (S410) by the grouping method described above can provide the charger operator / manager with the grouped results based on information such as the discharge interruption frequency or total amount, thereby indicating the charger group that is most detrimental to the stabilization of the power system (10) among the chargers (200) being operated / managed, and consequently, this means that there is a problem with the charging infrastructure. Therefore, the charger operator / manager can help systematically manage the lifespan of the charger (200) by scheduling it based on the grouping results of the analysis step (S400) or the charger management step (S410) rather than randomly determining the replacement or repair time of the charger (200).

[0105] When using the grouping method described above in the analysis step (S400) or the charger management step (S410), the chargers (200) are not uniformly managed by the initial set grouping such as the initial parameter values, but rather the affiliation of each grouped object changes according to changes in the surroundings or situation, thereby increasing the ability to respond to event occurrence.

[0106] For example, in FIG. 10, the initially set initial group centers (1120, 1220, 1320) are changed to the final group centers (1122, 1222, 1322) according to the new grouping, and the groups are also moved accordingly. At this time, it can be seen that a given charger (1400) initially belonged to the first charger group (G1, 1100), but moved out of the first group (1102) due to the new grouping and now belongs to the new second charger group (G2, 1202). The given charger (1400) may correspond to the 10th charger of FIG. 9. In FIG. 9, it can be seen that the 10th charger initially belonged to the first charger group (G1) to which the 1st and 9th chargers belong, but moved to the second charger group (G2) to which the 2nd, 4th, 5th, and 6th chargers belong due to the grouping of the analysis result (S400).

[0107] As such, the charger management step (S410) of the present invention can be more effectively applied to an environment where the power input / output of a distributed load (80) changes rapidly, where the power input / output is concentrated at a specific time, or where the environment is greatly influenced by external factors.

[0108] The distributed load (80) may include an electric vehicle (100) and an electric vehicle charger (200). The electric vehicle (100) functions as a moving ESS, and may cause rapid output generation such as rapid charging. Time-of-day imbalances frequently occur in which output is concentrated at specific times such as rush hour. The load is greatly affected by the season, and the charging status may be greatly affected by the external environment of the power system (10). Therefore, the distributed load (80) of the present invention may be suitable for protection and analysis using a system protection step (S300) or an analysis step (S400).

[0109] Step 430 (S430) can derive a correlation between the vehicle-mounted bidirectional power conversion unit (110) and the charger (200). Step 430 (S430) can complement the charger management step (S410), and may be due to the fact that the main location where power is converted is the electric vehicle (100) rather than the charger (200). For example, the specification data (D14) of the reference data (D10) may include not only the charger specifications but also the specifications of the electric vehicle (100). The specifications of the onboard power conversion unit (110) may vary depending on the vehicle model, and compatibility with the charger (200) may vary depending on the onboard power conversion unit (110). Based on the results of the charger management step (S410), if the correlation between the vehicle-mounted power conversion unit (110) of step 430 (S430) and the equipped charger (200) is added, the lifespan of each charger group can be predicted more accurately.

Claims

1. A charging cable connecting the electric vehicle and the charger, and a power measurement unit that collects power data from the power system; A charger communication control module that communicates with the electric vehicle communication control module that controls communication between the inside of the electric vehicle and the charger for rapid or slow charging and exchanges data; A system protection unit that takes measures to protect the system against instability that occurs during power transmission between distributed loads including electric vehicles and chargers and the power system; including; If the power conversion of the power conversion unit mounted on the above electric vehicle does not operate normally, the above system protection unit is a system stabilization device that commands the electric vehicle or charger to stop discharging or reverse transmission so that instability does not occur in the power system.

2. In paragraph 1, The above system protection unit is, If the system data including the system information value transmitted from the above charger communication control module to the electric vehicle communication control module differs by a certain range or more from the power quality status of the power data measured in the power system, the discharge of the electric vehicle or charger is stopped to protect the power system. If the power data including frequency, phase, and voltage measured from the charging cable and power system are out of a certain range, the discharge of the electric vehicle or charger is stopped to protect the power system. A system stabilizing device that takes system protection measures when a power quality abnormality occurs in the power data measured by the above power measuring unit, and the power quality abnormality means that the measured data including the power data includes components including frequency, phase, and voltage that are out of the established range or exceed the threshold when compared with the reference data.

3. In paragraph 1, The above system protection unit performs an analysis step including a charger life prediction step after the system protection step in which system protection measures are performed. In the above analysis step, the system protection unit predicts or manages the life of the charger by using parameters including the discharge interruption frequency and the total accumulated discharge interruption amount of each charger by the system protection step. The above analysis step is a charger management step including a charger life prediction including repair or replacement of the charger, or a system stabilization device including a correlation derivation step between a vehicle-mounted power converter and a charger.

4. In paragraph 1, The above system protection unit is, Determine whether the electric vehicle or charger is discharging or recharging, A circuit breaker sends a cut-off signal to the charger that is judged to have stopped discharging. If the above charger is single, the reverse transmission from the charger to the power grid is stopped due to the discharge being interrupted by the circuit breaker. A system stabilizing device in which reverse transmission is performed by the remaining chargers, excluding the charger whose discharge is stopped by the circuit breaker, when multiple chargers are installed.

5. In paragraph 1, The upper grid protection unit performs data comparisons to determine grid protection actions, including discharge interruption. The above system protection unit receives information necessary for data comparison from at least one of the power measurement unit, the charger communication control module (220), or the server. The above power measurement unit transmits measurement data including power data to the system protection unit, The above charger communication control module or server transmits reference data including system data or specification data to the system protection unit. A system stabilization device in which specification data including the standards or specifications of the power conversion unit mounted on the electric vehicle is transmitted from the electric vehicle communication control module to the charger communication control module or server, and then transmitted again to the system protection unit.

6. In paragraph 1, The above system protection unit detects or manages instability factors that occur during power transmission between distributed loads and power systems. The above distributed load includes an electric vehicle equipped with the above charger and a vehicle-mounted power converter, The above system protection unit is, Comparing the reference data including the required power value transmitted between the electric vehicle communication control module and the charger communication control module with the measurement data collected by the power measurement unit, If a difference exceeding the range determined by the above mutual comparison occurs, the discharge function of the electric vehicle or charger is stopped to protect the power system. The above-mentioned electric vehicle or charger discharge interruption is a system stabilization device including the interruption of discharge from the electric vehicle to the charger, or the interruption of reverse transmission from the charger to the power grid.

7. In paragraph 1, A charger including a power supply unit that supplies electricity to an electric vehicle is installed in multiple units at a charging station. It includes a center distribution module that is connected to multiple chargers at one end and connected to the power grid at the other end. The above center distribution module includes an extended grid protection unit or grid protection unit, The above extended system protection unit performs system protection measures for the charging station separately from the system protection unit installed in each charger, and In the case where the above system protection unit is individually installed in each charger, the extended system protection unit transmits the individually determined system protection measures to each system protection unit. A system stabilization device that, when the above system protection unit is not installed for each charger and only an extended system protection unit is equipped, issues a discharge stop command to at least one of the charge controller, charger communication control module, and circuit breaker of each charger after the extended system protection unit determines the system protection measures.

8. In paragraph 1, The above system protection unit is, After grid protection measures including discharge interruption, charger management including charger life prediction is performed, For the above charger management, grouping is done according to parameters related to the life of the charger. The above parameters include the frequency of discharge interruptions and the total accumulated amount of discharge interruptions. The initial charger group and the initial center of the charger group are moved by the above grouping, The charger group moved by the above grouping is classified according to the grade of charger life prediction. The above system protection unit is a system stabilization device that provides scheduling for replacement or repair times for a group of chargers according to the predicted life expectancy of the chargers.

9. In paragraph 1, The above system protection unit performs charger management including charger life prediction, Chargers are divided into several charger groups based on parameters related to the life of the charger. The number of the above charger groups is, When calculating the distance between charger groups, the sum of the parameter variances is used as the basis. A system stabilization device that determines the distance between groups based on the degree to which each charger in a charger group deviates from the average, or the square of the deviation, summed over all chargers.

10. In paragraph 1, The above system protection unit performs charger management including charger life prediction, For the above charger management, grouping is done according to parameters related to the life of the charger. The initial charger group and the initial center of the charger group are moved by the above grouping, Each charger belongs to one of several charger groups based on its distance from the initial group center. The above distance includes the Euclidean distance or the squared Euclidean distance, The Euclidean distance is the Pythagorean distance between each charger and the initial group center, based on the parameter values ​​assigned to each charger, and the squared Euclidean distance is the square of the Euclidean distance.

11. In paragraph 1, The above system protection unit performs charger management including charger life prediction, For the above charger management, grouping is done according to parameters related to the life of the charger. The initial charger group and the initial center of the charger group are moved by the above grouping, The charger group moved by the above grouping is classified according to the grade of charger life prediction. A system stabilizing device in which the group of each charger changes according to changes in the situation including the charging infrastructure around the charger when using the above grouping.

12. In paragraph 1, The above system protection unit performs an analysis step including predicting the life of the charger, The above analysis step includes a charger management step including charger life prediction including repair or replacement of the charger, or a correlation derivation step between the vehicle-mounted power converter and the charger. The above correlation derivation step is a system stabilization device that complements the charger management step by adding a correlation between a vehicle-mounted power converter and a charger based on the results of the charger management step, thereby more accurately predicting the lifespan of each charger group.

13. In paragraph 1, The data transmitted to the above system protection unit includes reference data and measurement data, The above grid protection measures, including the discharge stop or reverse transmission stop of electric vehicles or chargers, are determined by mutual comparison of the above reference data and measurement data. The above reference data is the reference setting value, The above measurement data includes power data collected by the power measurement unit and compared with the reference data by the system protection unit. A system stabilization device in which the above measurement data is sent from the power measurement unit to the charging controller or a separate database, stored therein, and then transmitted to the system protection unit, or transmitted directly from the power measurement unit to the system protection unit.

14. In paragraph 1, When the charging cable connected to the above charger is connected to the electric vehicle, the electric vehicle communication control module detects the PWM signal and starts communication by sending a signal to the charger communication control module of the charger. A system stabilization device in which the electric vehicle and the charger are electrically connected by the charging cable, so that the electric vehicle communication control module and the charger communication control module exchange signals or information with each other.

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