JP6060397B2 - Vehicle charging system - Google Patents

Description

  The present invention relates to a vehicle charging system for simultaneously charging a plurality of vehicles such as electric vehicles.

  With the spread of electric vehicles and the like, there is an increasing demand for a vehicle charging system that can charge a plurality of vehicles simultaneously.

  Conventional charging systems for vehicles that can be charged at the same time are mainly premised on introduction to apartment houses and business establishments. When charging multiple electric vehicles at the same time, the amount of electricity used is drastically reduced. In order to avoid the danger of exceeding the contract power by rising to the maximum, the maximum power consumption in the entire vehicle charging system is set in advance and charging control is performed so that charging is performed within the allowable range. (Patent Document 1).

  As a conventional charging control technique, a method (method 1) for starting charging control via a CPLT signal when the sum of charging currents of a plurality of vehicles exceeds a threshold value (<contract current), or a charging device based on the CPLT signal There is known a method (method 2) in which the number of vehicles connected to the vehicle is estimated and the total amount of charging power is predicted to perform charging control.

  However, in the above method 1, a time lag occurs between the timing of starting charging control and the result of the control being reflected in the actual charging current value. During this time, a new vehicle is connected, and the charging power is allowed. There was a problem that could not deny the possibility of exceeding the range. Further, in the above method 2, even when the potential change of the CPLT signal suggests connection of the vehicle, for example, when the vehicle is in a charging standby state and actual charging is not performed, There was a problem that the charge power value and the predicted value are likely to be misaligned, making it difficult to perform appropriate control.

  Furthermore, there is a problem that a control system that links the CPLT signal and actual charging becomes complicated.

JP 2001-69678 A

  The object of the present invention is to solve the above-mentioned problem, and when charging a plurality of vehicles at the same time, properly grasp the required amount of charging power and efficiently charge without exceeding the allowable range of charging power. A vehicle charging system that can be performed is provided with a simple configuration.

The charging system of the present invention made to solve the above problems is a vehicle charging system provided with a vehicle charging device on a plurality of electric paths,
Current measuring means for measuring the current of each circuit;
A charging control unit that controls charging of the vehicle connected to each vehicle charging device, and a control unit that connects each charging control unit by communication means,
In the control unit,
Based on the charging current measured by the current measuring means, charging determination means for determining charging start of the vehicle connected to the vehicle charging device;
In response to the charge start determination by the charge determination means, add the current assumption value determined for the vehicle charging device to which the vehicle is connected, current addition means for obtaining a total current assumption value;
Current limiting means for limiting charging of each connected vehicle without stopping charging to each connected vehicle when the total current assumed value added by the current adding means exceeds a preset threshold value. It is characterized by comprising.

  According to a second aspect of the present invention, in the charging system according to the first aspect, when the charging current is equal to or greater than a predetermined value, the connection determining unit determines that the vehicle has started charging and determines the connection. To do.

  According to a third aspect of the present invention, in the charging system according to the first aspect, the current limiting means limits the charging equally to all connected vehicles.

  According to a fourth aspect of the present invention, in the charging system according to the first aspect, the control unit further includes a restriction releasing means for releasing the charging restriction.

  Since the vehicle charging system according to the present invention determines the connection between the charging device and the vehicle based on the charging current measured by each charging device, unlike the control that links the CPLT signal and the actual charging, a simple system configuration Thus, charge control can be performed promptly after a new connected vehicle is connected. That is, according to the present invention, when charging a plurality of electric vehicles at the same time, it is possible to appropriately grasp the necessary amount of charging power and efficiently charge without exceeding the allowable range of charging power. it can.

1 is an overall explanatory diagram of a vehicle charging system according to the present invention. 1 is an overall explanatory diagram of a vehicle charging device. It is a block diagram of the charge control part of the charging device for vehicles. It is a block diagram of the determination part which comprises the charge control part of the charging device for vehicles. It is a block diagram of a control unit. It is a figure which shows an example of the identification database inside a control unit. It is a flowchart of a charge restriction process. It is an Example of charge restriction. It is a flowchart of a charge restriction cancellation process.

  Preferred embodiments of the present invention are shown below.

  The present invention relates to a vehicle charging system that is optimal for a plurality of vehicle charging devices installed in, for example, ordinary houses and residential apartments, and relates to a vehicle charging system that charges a plurality of vehicles simultaneously. FIG. 1 is an overall explanatory view of the vehicle charging system.

  In FIG. 1, 2 is a distribution board, 3a-3c is a vehicle charging device, and 4a-4c is a vehicle such as an electric vehicle. The distribution board 2 supplies electric power to the plurality of vehicle charging devices 3 a to 3 c through an electric path 21 branched from the main bus 7. Inside the distribution board 2, a control unit 10 that determines whether or not charge restriction is necessary and outputs a charge restriction command to the charge control unit 18 of the vehicle charging device 3 is arranged, and the vehicle charging devices 3 a to 3 c The charging control unit 18 provided inside is connected to the communication line 32. The communication line 32 may be wireless, and the control unit 10 may be provided separately from the distribution board 2.

  As shown in FIG. 2, each of the vehicle charging devices 3 a to 3 c connects the charging cable to the vehicle and charges the vehicle. Each vehicle charging device 3 generates a charging control signal (CPLT signal) to be transmitted to the vehicle 4 through a signal line built in the charging cable, in addition to the relay 17 that opens and closes the electric circuit 21 connected to the charging cable. A CPLT circuit is built in, and a charge control unit 18 that performs open / close control of the relay 17 and the like, and a CT 19 as a current measurement unit that measures the charge current MC flowing through the electric circuit 21 are provided. Note that the current measuring means may be provided inside the distribution board 2. In the present invention, the connection between the vehicle charging device 3 and the vehicle 4 may be performed by non-contact charging using electromagnetic induction or the like. In this case, the charge control signal is transmitted between the vehicle charging device 3 and the vehicle 4 using wireless communication.

  As shown in FIG. 3, the charging control unit 18 includes a determination unit 22, a CPLT circuit 23, and a communication unit 24, and controls charging of the vehicle 4 connected to the vehicle charging device 3.

  The communication means 24 transmits the charging current MC measured by the CT 19 to the control unit 10 together with the individual identification numbers of the vehicle charging devices 3a to 3c. In addition, a charge restriction command is received from the control unit 10.

  The CPLT circuit 23 oscillates a CPLT signal having a predetermined duty ratio when a charging cable is connected to the vehicle and preparation for charging is completed. The CPLT signal is a pilot signal having a duty ratio that is set according to the magnitude of the rated current TC of the vehicle charging device 3, and the connection state and vehicle charging between the vehicle 4 and the vehicle charging device 3. The allowable current value KC of the device 3 is notified to the vehicle 4. The larger the duty ratio, the greater the vehicle charging device 3 can supply.

  The allowable current value KC has an initial value of 80% of the rated current TC of the vehicle charging devices 3a to 3c, but is changed in response to a charge limiting command from the current limiting means 30 described later. The vehicle 4 is designed to make a charge request at the notified allowable current value KC or less, and the charging current reaches a predetermined value MHC below the allowable current value KC within a certain time from the start of charging, and is almost predetermined during the charging time. The value MHC is maintained.

  In the determination unit 22, a current setting unit 26 that changes the allowable current value KC in response to a charge limiting command from the current limiting unit 30 and sets a CPLT signal having a duty ratio corresponding to the allowable current value KC, and a CPLT signal Charging control means 25 for controlling the opening and closing of the relay by the potential of

  When the vehicle is connected to the vehicle charging devices 3a to 3c, the potential of the CPLT signal changes due to the internal resistance of the charging circuit (not shown) of the vehicle. Is closed, a closing signal is transmitted to the relay 17, and charging of the in-vehicle battery is started (mode 2 control).

  As shown in FIG. 5, the control unit 10 includes an identification database 27, a charge determination unit 28, a current addition unit 29, a current limit unit 30, and a limit release unit 31. The restriction process is executed at a constant time interval (for example, 5 seconds), and the charge restriction release process shown in FIG. 9 is executed at a constant time interval (for example, 15 seconds) different from the charge restriction process. If the restriction process is executed a predetermined number of times (for example, 3 times), the release process may be executed once.

  As shown in FIG. 6, the identification database 27 holds assumed current values AC determined for each individual identification number of the vehicle charging devices 3 a to 3 c. The assumed current value AC is a value that assumes a predetermined value MHC that differs for each vehicle for each connected vehicle charging device. In the present embodiment, the initial value of the permissible current value KC of each vehicle charging device is used. If all the vehicle charging devices are the same, the current assumed value AC may be set to a uniform predetermined value (for example, 15 A), and in this case, an identification database is not necessary.

  When the charging current MC measured by CT19 exceeds a certain value MCL (for example, 1A), the charging determination unit 28 determines that the vehicle is connected to the charging device and charging is started. That is, the vehicle connection determination and the charge start determination can be performed regardless of the mode 2 control, so that there is a time lag between the connection of the charging cable to the vehicle and the actual charging, or the control unit 10 and the charging control. It is not affected by the occurrence of a communication error between the units 18.

  The current adding means 29 adds 1 to the number N of connected vehicles when the charging determination means 28 determines the charging start. At the same time, the assumed current value AC is added, and the total assumed current value TAC is calculated before the charging current MC reaches the predetermined value MHC.

  The current limiting unit 30 outputs a charge limiting command to the charging control unit 18 when the total assumed current value TAC exceeds a preset threshold value TBC (for example, 80% of the main rated current of the distribution board).

  Hereinafter, the operation of the charging restriction process will be described with reference to FIG. In the present embodiment, in order to simplify the description, it is assumed that the main rated current 40A of the distribution board and the set threshold value are set to 32A. The assumed current values AC of the vehicle charging devices 3 a to 3 c are all 15 A, and there is no load other than the vehicle charging device 3.

  When charging is started, the charging current MC is measured by the CT 19 inside each of the vehicle charging devices 3a to 3c. The charging current MC is transmitted to the control unit 10 together with the individual identification numbers of the vehicle charging devices 3a to 3c, and is input to the charging determination means 28 (ST1, ST2).

  When the input charging current MC is equal to or greater than a certain value MCL (for example, 1 A), the charging determination unit 28 determines whether to start charging the vehicle (ST3).

  When the charging determination unit 28 determines that the vehicle charging is started, the current adding unit 29 adds 1 to the total number of connected vehicles N of the entire vehicle charging system and records it in the memory of the control unit 16 (ST4). At the same time, the assumed current value AC held in the identification database 27 is added to calculate the total assumed current value TAC (ST5).

The current limiting means 30 determines whether or not the total assumed current value TAC has exceeded the set threshold value TBC (ST6), and when it exceeds the set threshold value TBC , the charging of each connected vehicle is not stopped. Then, a charge restriction command is output (ST7). The charge restriction command is output to all of the vehicle charging devices 3 for which the charging determination unit 28 determines that charging of the vehicle is started.

  Charge restrictions are equally applied to all connected vehicles. Here, “equal” means control for reducing the allowable current value KC at a constant rate.

  The charge limit sets a new allowable current value KC. The changed new allowable current value KC is a value obtained by dividing the set threshold value TBC by the number N of connected devices.

  The current limiting means 30 inputs the changed allowable current value KC to the charging control unit 18 of each of the vehicle charging devices 3a to 3c to modulate the duty ratio. The vehicle makes a new charge request according to the allowable current value KC.

  If the input charging current MC is less than the constant value MLC in ST2, the charging restriction process is terminated without considering that the vehicle is connected. In ST7, if the total assumed current value TAC is less than the set threshold value, the charging limitation process is terminated without performing the charging limitation.

  FIG. 8 is a time chart showing how the vehicles 4a to 4c are sequentially charged.

At time t1, charging of the vehicle 4a is started, and at time t2, the charging current MC reaches a predetermined value MHC of 15A. At time t2, the vehicle 4b also starts charging. At this time, the total current assumption value TAC is 30 A, which is less than the set threshold value, so that the charge restriction command is not output. At time t3, the vehicle 4c starts charging, and at time t4, the charging current MC reaches a constant value MLC. Since the assumed total current value TAC calculated at time t4 exceeds the set threshold value at 45A , the charge restriction command is output without stopping charging.

  As a result, the allowable current value KC of the vehicle charging device 3a is lowered. The allowable current value KC of the vehicle charging devices 3b and 3c is also reduced, and the charging current MC of the vehicles 4b and 4c is limited in charge without reaching the predetermined value MHC of 15A. The newly set allowable current value KC is 10.7 A obtained by dividing the setting threshold value TBC by the number of connected devices.

  In this way, since the determination of the vehicle to be charged is determined by the measured charging current MC, a new connected vehicle is connected with a simple system configuration, unlike the control that links the CPLT signal and the actual charging. After that, charging control can be performed promptly. In addition, since a value obtained by dividing the set threshold TBC by the number of connected devices is set as a new allowable current value, charging can be performed efficiently.

  In the restriction release means 31, when the charging of the vehicle 4a has expired and the total charging current TMC, which is the sum of the charging currents MC measured by the vehicle charging devices 3a to 3c, falls below the set threshold, the duty ratio of the CPLT signal is changed. Control to return to the initial value is performed. Hereinafter, the flow of the charge restriction release process will be described with reference to FIG.

  The charging current MC measured by the CT 19 inside each of the vehicle charging devices 3a to 3c to which the vehicle is connected is input to the charging determination unit 28 via the communication unit 24 (ST101).

  The charging current MC of each of the vehicle charging devices 3a to 3c is added, and the total measured current TMC is calculated (ST102).

  Subsequently, the added value is compared with the set threshold value TBC (ST103), and if the total measured current TMC is less than the set threshold value, the charging restriction is released (ST104). Release of the charging restriction is performed by inputting the initial value of the allowable current value KC to the current setting means 26 of each vehicle charging device.

  If the total measured current TMC is equal to or greater than the set threshold value TBC in ST3, the charge restriction is not released and the charge restriction release process is terminated (ST105).

  In the above embodiment, the charging restriction is performed equally for all connected vehicles. However, only a specific vehicle may be subject to the charging restriction, or the charging current may be made uneven. For example, the target vehicle may be specified based on the connection time, the amount of charge until charging is limited, and the charge current of the vehicle having a short connection time may be larger than that of the vehicle having a long connection time.

DESCRIPTION OF SYMBOLS 1 Trunk board 2 Distribution board 3a-3c Vehicle charging device 4a-4c Vehicle 6 General load 7 Main bus line 8a-8d Branch line 9 First power meter 10 Control unit 11 Signal line 12 Main breaker 14a-14d Power supply line 15a to 15d Charge control breaker 16 Determination unit 17 Relay 18 Charge control unit 19 CT
21 Electric path 22 Determination unit 23 CPLT circuit 24 Communication unit 25 Charging control unit 26 Current setting unit 27 Identification database 28 Charging determination unit 29 Current addition unit 30 Current limiting unit 31 Limit release unit 32 Communication line

Claims (4)

A vehicle charging system including a vehicle charging device on a plurality of electric paths,
Current measuring means for measuring the current of each circuit;
A charging control unit that controls charging of the vehicle connected to each vehicle charging device, and a control unit that connects each charging control unit by communication means,
In the control unit,
Based on the charging current measured by the current measuring means, charging determination means for determining charging start of the vehicle connected to the vehicle charging device;
In response to the charge start determination by the charge determination means, add the current assumption value determined for the vehicle charging device to which the vehicle is connected, current addition means for obtaining a total current assumption value;
Current limiting means for limiting charging of each connected vehicle without stopping charging to each connected vehicle when the total current assumed value added by the current adding means exceeds a preset threshold value. A vehicle charging system comprising:   2. The vehicle charging system according to claim 1, wherein when the charging current is greater than or equal to a predetermined value, the charging determination unit determines that charging of the vehicle has started and performs charging start determination.   2. The vehicle charging system according to claim 1, wherein the current limiting means uniformly limits charging for all connected vehicles.   The vehicle charging system according to claim 1, further comprising restriction release means for releasing the charge restriction in the control unit.