Charging device, power system including the charging device, and charging method

Abstract

To provide a charging device, a power system, and a charging method, capable of preventing chattering in which a plurality of power control units frequently switch between charging and non-charging.SOLUTION: Provided is a charging device that is switched between an energized state where charging for a charging target including an electric vehicle (EV) connected to the charging device is performed and a non-energized state where the charging is not performed. In the charging device, an adjustment region for switching according to a priority to bring the charging device into the energized state is set, and, when it is determined whether the charging device is to be brought into the energized state or the non-energized state at least based on the adjustment region and a command value sent from a centralized management unit based on a target power value and the power demand of the entire system, the determination of switching from the non-energized state into the energized state is prohibited if the target power value is approximate to the power demand.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a charging device, a power system including the charging device, and a charging method. [Background technology]

[0002] BACKGROUND ART In recent years, power systems that manage a plurality of power devices connected to a power system and control power transmitted and received between the power system and the power system have become increasingly common.

[0003] For example, Patent Document 1 discloses a centralized management device and multiple power control devices that manage multiple power devices, where the centralized management device has a detection means for detecting power to be adjusted, a means for calculating an index for adjusting individual output power, and a means for transmitting the index to the multiple power control devices, and the power control devices have a means for calculating individual target power based on an optimization problem using the index and controlling the individual output power. As a result, each power control device determines power based on the index, and the centralized management device changes the index to decrease power if the power to be adjusted is greater than the target value, and changes the index to increase power if the power to be adjusted is smaller, thereby making it possible to control the power to be adjusted to the target value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017-150376 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional technologies such as Patent Document 1, when a power control device discontinuously changes charging and discharging power, such as with ON / OFF control, the power control device switches ON / OFF based on a command value, and it is possible to provide hysteresis to the ON / OFF. However, when multiple such power control devices are connected, a problem arises in that chattering occurs, where the power control device repeatedly switches ON / OFF in an attempt to make the power demand follow the target power.

[0006] The present invention was devised in light of the above-mentioned circumstances, and aims to provide a charging device, a power system, and a charging method that can prevent chattering, which occurs when multiple power control devices frequently switch between charging and non-charging. [Means for solving the problem]

[0007] One aspect of the present invention is a charging device that can be switched between a powered state in which a charging target, including a connected electric vehicle, is charged, and a disconnected state in which charging is not performed, and is equipped with a switch that switches between the powered state and the disconnected state, a priority setting unit that sets an adjustment range for the switching according to the priority of switching to the powered state, and a judgment unit that determines whether to switch to the powered state or the disconnected state based on at least a command value sent from a centralized management device based on a target power value and the power demand of the entire system, and based on the adjustment range, and is characterized in that when the target power value and the power demand are similar, the judgment unit is prohibited from determining whether to switch from the disconnected state to the powered state. [Effects of the Invention]

[0008] According to one aspect of the present invention, chattering caused by multiple power control devices frequently switching between charging and non-charging can be prevented. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing the overall configuration of a power system according to this embodiment. [Figure 2]FIG. 2 is a block diagram showing the internal configuration of the charging device according to this embodiment. [Figure 3] FIG. 3 is a diagram showing the problems of the conventional example. [Figure 4] FIG. 4 is a diagram showing the change in threshold and price (command value) (upper diagram) and the ON / OFF state at that time (lower diagram) in the control of the conventional example. [Figure 5] FIG. 5 is a flowchart showing an example of a process for setting a price (command value) transmitted by the centralized control device F (upper diagram) and an example of control of the charging device A (lower diagram). [Figure 6] FIG. 6 is a diagram showing the ON / OFF switching state and the transition of the adjustment region (threshold) before improvement (upper diagram) and after improvement by this embodiment (lower diagram). [Figure 7] FIG. 7 shows the ON / OFF switching state (upper diagram) and the change state of the adjustment region (threshold) (lower diagram) when a countermeasure (setting method) for the secondary issue is implemented. [Figure 8] FIG. 8 is a diagram showing an example of setting the adjustment region (threshold) when a countermeasure (setting method) for dealing with a secondary problem is taken. [Figure 9] FIG. 9 shows the ON / OFF switching state (upper diagram) and the change in adjustment area and price (lower diagram) when a countermeasure (setting method) for the secondary issue is implemented. [Figure 10] FIG. 10 is a diagram showing another example of how to deal with the secondary problem (tilt adjustment). [Figure 11] FIG. 11 is a diagram showing another example of how to deal with the secondary problem (tilt adjustment). [Figure 12] FIG. 12 shows the ON / OFF switching state (upper diagram) and the transition of the adjustment area and price (lower diagram) when another example of dealing with the secondary issue (gradient adjustment) is implemented. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Here, an "electric vehicle" is a mobile object equipped with an electric motor as a power source and a storage battery that supplies power to the electric motor. The "object to be charged, including an electric vehicle" includes not only so-called electric vehicles powered only by an electric motor, but also plug-in hybrid vehicles equipped with an internal combustion engine. The "object to be charged, including an electric vehicle" includes not only automobiles but also other vehicles such as two-wheeled vehicles (electric motorcycles, electrically assisted bicycles), and also automated guided vehicles. Therefore, in the following embodiments, an electric vehicle (EV) may be described as an example of an object to be charged, but this is not limiting and other objects may also be charged.

[0011] (Power System Configuration) FIG. 1 is a block diagram showing the overall configuration of a power system according to a first embodiment. A power system G is connected to a power grid E and can transmit and receive power from the power grid E. The power system G controls output power using an autonomous distributed cooperative control method so that power at a connection point between the power system G and the power grid E (hereinafter referred to as "connection point power") becomes a target power. In the following description, when the power system G transmits power to the power grid E (reverse power flow), the connection point power is taken as a positive value. On the other hand, when the power system G receives power from the power grid E, the connection point power is taken as a negative value. The power system G includes a centralized management device F, power conditioners C1 to Cn, power conditioners D1 to Dm, charging devices A1 to Ak, and a user information database H. In this embodiment, as an example, the power system G is installed in a business office, and the charging devices A1 to Ak constitute a charging station located in the business office parking lot for charging employees' commuting vehicles, business vehicles, and the like.

[0012] The centralized control device F monitors the connection point power and calculates an index for instantaneous value control of the connection point power to the target power. In this embodiment, the centralized control device F uses the power value detected at the connection point between the power system G and the power grid E as the connection point power P(t). The centralized control device F may receive detection values ​​of input / output power detected by each of the power conditioners C1-Cn, D1-Dm and each of the charging devices A1-Ak, and use the total value calculated from these detection values ​​as the connection point power P(t). The centralized control device F calculates a command value pr based on the difference between the set target power Pc and the connection point power P(t), and transmits a common command value pr to each of the power conditioners C1-Cn, D1-Dm and each of the charging devices A1-Ak. The communication method is not limited, and may be wired communication or wireless communication.

[0013] Each of the power conditioners C1 to Cn is connected to a solar cell, and converts DC power generated by the solar cell into AC power and outputs it. Each of the power conditioners C1 to Cn includes a target power calculation unit 91 and an output control unit 92. The target power calculation unit 91 uses a command value pr received from the centralized management device F to calculate a target power value Pref, which is a target value for the output power of the power conditioner itself, based on a preset optimization problem. The output control unit 92 controls the output power based on the target power value Pref calculated by the target power calculation unit 91.

[0014] Each of the power conditioners D1 to Dm is connected to a storage battery and charges and discharges the storage battery. Although not shown in Fig. 1, each of the power conditioners D1 to Dm includes a target power calculation unit 91 and an output control unit 92, similar to the power conditioners C1 to Cn. An optimization problem suitable for charging and discharging the storage battery is set in advance in the target power calculation unit 91 of each of the power conditioners D1 to Dm.

[0015] Charging devices A1 to Ak are devices that charge the connected electric vehicles B1 to Bk, respectively. In the following, when the charging devices A1 to Ak are described without distinction, they will be referred to as "charging device A." When the electric vehicles B1 to Bk are described without distinction, they will be referred to as "electric vehicle B." Electric vehicle B is a vehicle that can run using an electric motor as a power source, and includes vehicles also equipped with an internal combustion engine (for example, plug-in hybrid vehicles). Electric vehicle B is equipped with a storage battery 3. Charging device A charges the storage battery 3 installed in electric vehicle B, which is connected to it by a charging cable 2. The electric motor of electric vehicle B operates using power stored in storage battery 3.

[0016] Each charging device A cannot control charging power, and switches between a powered state in which the connected electric vehicle B is connected to the power grid E and charged, and a disconnected state in which the connected electric vehicle B is disconnected and not charged. Note that each charging device A may also have a function to discharge the storage battery 3 of the connected electric vehicle B. The charging device A switches between the powered state and the disconnected state based on a command value pr received from the centralized control device F. In this embodiment, the charging device A switches between the powered state and the disconnected state taking into account the priority of charging, as will be described later. At that time, when the target power value and the power demand are similar, the charging device A suppresses switching from the disconnected state to the powered state, as will be described later. Details of the charging device A will be described later.

[0017] The user information database H stores various information related to the user of each electric vehicle B. The user information database H communicates with each charging device A and transmits necessary information to each charging device A. The communication method is not limited and may be wired communication or wireless communication. The various information includes the use time of the electric vehicle B, the planned driving distance, the battery capacity, the required charging rate, and the priority level. For example, if the electric vehicle B is a commuter vehicle, the use time is set as the user's return home time, and the planned driving distance is set as the user's commuting distance. Furthermore, if the electric vehicle B is a commercial vehicle, the use time is set as the user's business start time, and the planned driving distance is set as the driving distance according to the user's destination. The information included in the various information is not limited to these.

[0018] Based on a common command value pr received from the centralized control device F, each of the power conditioners C1-Cn, D1-Dm autonomously controls input / output power, and each of the charging devices A1-Ak autonomously switches between a powered state and a powered off state. This controls the output power (node ​​power P(t)) of the entire power system G to approach the target power Pc. For example, in this embodiment, the centralized control device F increases the command value pr when the node power P(t) is greater than the target power Pc, and decreases the command value pr when the node power P(t) is less than the target power Pc. The power conditioners C1-Cn, D1-Dm and each of the charging devices A1-Ak operate to decrease the node power P(t) as the command value pr received from the centralized control device F increases, and increase the node power P(t) as the command value pr decreases. A detailed description of the power conditioners C1-Cn, D1-Dm and the centralized control device F is omitted.

[0019] Next, details of charging device A will be described. Charging device A and electric vehicle B are connected by a charging cable 2. The charging connector of charging cable 2 is connected to the charging port of electric vehicle B, and the charging plug is connected to the charging outlet of charging device A. Charging device A communicates with user information database H and receives various information from user information database H. In this embodiment, charging device A also communicates with electric vehicle B connected by charging cable 2, and receives information from electric vehicle B such as the current state of charge (SoC) and storage battery capacity of storage battery 3. Note that the communication method is not limited, and may be wired communication or wireless communication. In the case of wired communication, a communication line arranged separately from the power line of charging cable 2 may be used, or PLC (Power Line Communication) communication in which a communication signal is superimposed on the power line may be performed.

[0020] 2 is a block diagram showing the internal configuration of the charging device A. The charging device A includes a control unit 11, a switch 12, a charging outlet 13, a connection detection unit 14, and a receiving unit 15.

[0021] Charging outlet 13 is an outlet for connecting electric vehicle B to charging device A, and is connected to a charging plug of charging cable 2 connected to electric vehicle B. Connection detection unit 14 detects that electric vehicle B has been connected to charging device A. Specifically, connection detection unit 14 detects whether the charging plug of charging cable 2 connected to electric vehicle B is connected to charging outlet 13. Note that connection detection unit 14 may detect that electric vehicle B has been connected to charging device A using other methods. Connection detection unit 14 outputs the detection result to control unit 11. Receiving unit 15 receives command value pr from centralized management device F, and receives information from electric vehicle B and user information database H. Receiving unit 15 outputs the received command value pr and various information to control unit 11.

[0022] The switch 12 is disposed inside the charging device A on a connection line connected to the charging outlet 13 of the charging device A, and is a switch that switches between a powered state in which the electric vehicle B is charged and a powered-off state in which the electric vehicle B is not charged. When the switch 12 is in a closed state (on), the charging device A is in a powered-on state and the electric vehicle B is charged. On the other hand, when the switch 12 is in an open state (off), the charging device A is in a powered-off state and the electric vehicle B is not charged. The switch 12 switches based on the determination result input from the control unit 11.

[0023] The control unit 11 makes a decision to switch the switch 12 based on the command value pr and various information input from the receiving unit 15 and the detection result input from the connection detecting unit 14, and outputs the decision result to the switch 12. In this embodiment, the control unit 11 includes a decision index calculation unit 111, a decision unit 112, a charging rate acquisition unit 113, a storage battery capacity acquisition unit 114, a user information acquisition unit 116, and a guidance index acquisition unit 117.

[0024] The charging rate acquisition unit 113 acquires the charging rate of the storage battery 3 of electric vehicle B received from electric vehicle B from the information input from the receiving unit 15. The charging rate acquisition unit 113 outputs the acquired charging rate to the judgment index calculation unit 111 and the judgment unit 112. The storage battery capacity acquisition unit 114 acquires the storage battery capacity of electric vehicle B received from electric vehicle B from the information input from the receiving unit 15. Note that the storage battery capacity acquisition unit 114 may acquire the storage battery capacity from information received from the user information database H. The storage battery capacity acquisition unit 114 outputs the acquired storage battery capacity to the judgment index calculation unit 111 and the judgment unit 112.

[0025] The user information acquisition unit 116 acquires, from the information input from the receiving unit 15, information received from the user information database H. The user information acquisition unit 116 outputs the acquired information to the judgment index calculation unit 111 and the judgment unit 112.

[0026] The guidance index acquisition unit 117 acquires the command value pr input from the receiving unit 15. The guidance index acquisition unit 117 outputs the acquired command value pr to the determination index calculation unit 111 and the determination unit 112.

[0027] The judgment index calculation unit 111 calculates the command value pr using the command value pr input from the guidance index acquisition unit 117. In this embodiment, the judgment index calculation unit 111 calculates the command value pr as a command value pr (X=pr). Alternatively, the judgment index calculation unit 111 may calculate the command value pr for determining whether to make the device energized or de-energized using a known method based on a preset optimization problem.

[0028] The judgment index calculation unit 111 includes a priority setting unit 119. The priority setting unit 119 sets a switching adjustment range according to the priority of setting the power supply state. The switching adjustment range is, for example, a threshold or hysteresis (a range between an upper limit and a lower limit of a threshold) for determining switching between a power supply state (ON) and a power supply state (OFF) for a command value pr(X). In this embodiment, this adjustment range (threshold, hysteresis, etc.) changes according to the priority. In this embodiment, the command value pr is set to be larger as the margin up to the target power value with respect to the power demand of the entire system increases. Therefore, generally, the priority setting unit 119 makes the adjustment range (threshold, etc.) smaller as the priority increases and makes the adjustment range (threshold, etc.) larger as the priority decreases. This is shown in the table below. Centralized control device F: Increases or decreases the command value pr based on the difference between the target power and the actual power (power demand of the entire system). Target power > Actual power (power surplus): Increase command value Target power < Actual power (power shortage): Decrease the command value Charging device (priority setting unit 119): Sets a threshold value according to its own state (priority). When there is sufficient charge (low priority): Increase the threshold. If you want charging to start immediately (high priority): lower the threshold. Charging device (determination unit 112): Compares the command value with a threshold value to determine whether the charging device is ON or OFF. Command value > threshold: Turn ON (energized state). Command value < threshold: Set to OFF (disabled).

[0029] The determination unit 112 determines whether to set the switch to a conducting state (ON) or a non-conducting state (OFF) based on at least the command value pr transmitted from the centralized control device F based on the target power value and the power demand of the entire system, and the adjustment region set by the priority setting unit. For example, the determination unit 112 determines whether to set the switch to a conducting state or a non-conducting state by comparing the command value pr(X) input from the determination index calculation unit 111 with a predetermined value (threshold value). The determination unit 112 outputs the determination result to the switch 12. As described above, if the command value pr(X) is equal to or less than the threshold value, the determination unit 112 determines to set the switch to a conducting state, and instructs the switch 12 to set the switch to a closed state (ON) as the determination result. On the other hand, if the command value pr is greater than the predetermined value (threshold value), the determination unit 112 determines to set the switch to a non-conducting state, and instructs the switch 12 to set the switch to an open state (OFF) as the determination result. Note that the predetermined value is not limited.

[0030] Here, Fig. 3 is a diagram showing the problems with the conventional example. In the conventional example such as Patent Document 1, as shown in the upper diagram of Fig. 3, when the command value exceeds a threshold value (OFF → ON), the switch is switched to ON (energized state), and when the command value falls below the threshold value (ON → OFF), the switch is switched to OFF (non-energized state). Here, the lower diagram of Fig. 3 is a diagram showing chattering that occurs due to control in the conventional example.

[0031] In conventional examples, when each power control device switches on / off based on a command value and a threshold value, that is, when trying to make the power demand follow the target power, the problem occurs in that the multiple power control devices as a whole cause chattering, where the devices repeatedly switch on / off, as shown in the lower diagram of Figure 3 (within the dashed line frame in Figure 3).

[0032] Therefore, in this embodiment, chattering is prevented by prohibiting the determination unit 112 from determining whether to switch from the non-conductive state (OFF) to the energized state (ON) when the target power value and the power demand are close to each other. More specifically, the priority setting unit 119 may prohibit the determination unit 112 from determining whether to switch from the non-conductive state (OFF) to the energized state (ON) by not lowering the threshold of the adjustment region (i.e., not raising the priority) when the non-conductive state (OFF) is in the non-conductive state. As another specific example, the determination unit 112 may prohibit the determination of whether to switch from the non-conductive state (OFF) to the energized state (ON) when the target power value and the power demand are close to each other by subtracting from the command value the amount by which the threshold is lowered (i.e., the amount by which the priority is increased) when the non-conductive state (OFF) is in the non-conductive state (OFF) (i.e., by not raising the priority relative to the price value).

[0033] Figure 4 shows the changes in thresholds and prices (command values) (top diagram) and the corresponding ON / OFF states (bottom diagram) in conventional control. The solid line in the top diagram represents the upper limit of the adjustment range, i.e., the threshold for switching from OFF to ON, while the dashed line represents the lower limit of the adjustment range, i.e., the threshold for switching from ON to OFF. The light-colored rectangle in the bottom diagram represents the delay time from when the OFF-to-ON switch is determined to actually be ON, while the dark-colored rectangle represents the ON time. As shown in Figure 4, the price of the high-priority EV increases during the delay time, but the price of the low-priority EV2 does not increase (does not change) during the delay time. As a result, the high-priority EV receives more charge, and the priorities of the two EVs become closer, causing chattering.

[0034] In this embodiment, as described above, the threshold value of the adjustment region is not lowered (i.e., the priority is not increased) when the power supply is in the OFF state, or the amount by which the threshold value is lowered (i.e., the amount by which the priority is increased) when the power supply is in the OFF state is deducted from the command value when making a determination. This makes it possible to suppress switching from the OFF state to the ON state when the target power value and the power demand are close to each other, thereby preventing chattering. Note that the closeness of the target power value and the power demand includes the case where the target power value and the power demand match. Alternatively, the target power value and the power demand may be considered to be close to each other when the difference (ΔE) between the target power value and the power demand is less than a predetermined value.

[0035] In this embodiment, suppressing the switching from the power-off state (OFF) to the power-on state (ON) described above may cause disadvantages (secondary issues). One is that the charging speed may be slower than in the conventional example. The other is that the threshold value, which was lowered (priority was raised) as the time until departure time approached, may no longer be lowered. This may increase the number of cases where the required SOC cannot be secured at the time of departure for the user.

[0036] Therefore, in order to address this secondary issue, the following measures may be taken. <Solution to secondary issue (1): Tilt adjustment> Priority setting unit 119 may also adjust the rate at which the threshold for the adjustment region is increased when the EV is in a powered state (ON) (rate at which the priority is increased). More specifically, by increasing the threshold increase rate (slope) for low-priority EVs and decreasing the slope for high-priority EVs, high-priority EVs can be charged for a longer period, and low-priority EVs can be charged for a shorter period, giving other charging devices a chance to charge. This can reduce the decrease in charging speed that can occur when the priority is not changed when EVs are not being charged.

[0037] When a device with a low ON threshold is turned ON, the price is fixed and the threshold increases, so the charging duration is determined as follows: Charging duration = Hysteresis width ÷ Charging threshold increase rate On the other hand, when it turns OFF, the threshold is fixed and the price increases. When it is OFF, it remains OFF until the price and the next ON threshold, so the OFF duration is determined as follows: OFF duration = difference to ON threshold ÷ charge Therefore, as a setting example, if you want the charging threshold increase rate to be 1 / min and you want charging to continue for 10% SOC (=continuous charging for 60 minutes), set the hysteresis width to 60. If you want the device to turn off once and retry within 10 minutes, you can set the increase rate to 6 / min when there is no charge.

[0038] <How to deal with secondary issues (2): Hysteresis adjustment> The priority setting unit 119 may also adjust the width of the adjustment range (hysteresis) when the EV is in a powered state (ON). More specifically, as described below, the width of the hysteresis is widened as the priority increases, such as when the time until departure is shorter. This allows EVs with high priority to be charged for a longer period of time, while EVs with low priority are charged for a shorter period of time, giving other EVs a chance to charge. This makes it possible to alleviate the decrease in charging speed that can occur when the priority is not changed when EVs are not charging. Long time until departure: Narrow the hysteresis Short time to departure: Wide hysteresis

[0039] <Solution to secondary issue (3): Adjusting charging standby time> The determination unit 112 may also adjust the waiting time until power is turned on when it determines that the EV should be switched to the power-on state. This adjusts the delay time after determining that charging should start, thereby preventing a difference in delay time with other EVs and giving other EVs a chance to charge. This can therefore alleviate the drop in charging speed that can occur when the priority is not changed when not charging.

[0040] This concludes the description of each component of the power system of this embodiment. Note that data, programs, etc. required for this embodiment may be stored in a storage unit of the charging device 100 or the like (not shown).

[0041] (Power system processing) The upper diagram of FIG. 5 is a flowchart showing an example of a process for setting a price (command value) transmitted by the centralized control device F.

[0042] First, the central control device F sets the initial values ​​of the target power and price (SA-1).

[0043] Next, the centralized control device F monitors the connection point power and acquires the actual power (power demand of the entire system) (SA-2).

[0044] Then, the centralized control device F adds the difference α between the target power and the actual power to the price value (SA-3).

[0045] Continuing with the above processes of SA-2 and SA-3, the centralized control device F transmits the updated price pr to each charging device A. The above is an example of the price setting process of the centralized control device F.

[0046] Next, the lower diagram of FIG. 5 is a flowchart showing an example of control of the charging device A.

[0047] First, the priority setting unit 119 sets the initial value of the adjustment region (threshold value) for ON / OFF switching (SB-1).

[0048] Next, the guidance indicator acquisition unit 117 acquires the price pr from the centralized control device F via the receiving unit 15 (SB-2).

[0049] Then, the determination unit 112 determines whether the command value pr is greater than the threshold value (SB-3).

[0050] If the command value pr is greater than the threshold value (SB-3, YES), the judgment unit 112 controls the switch 12 to turn on the power (ON) (SB-4), and the priority setting unit 119 increases the threshold value (SB-5).

[0051] On the other hand, if the command value pr is not greater than the threshold (SB-3, NO), the judgment unit 112 controls the switch 12 to a non-operating state (OFF) (SB-6), and the priority setting unit 119 either does not change the threshold or increases it (SB-7). For example, if the increase (α) in the price (command value) remains unchanged or is within a predetermined range (Δ), the priority setting unit 119 may not change the threshold. Alternatively, if the increase (α) in the price (command value) is within the predetermined range (Δ), the judgment unit 112 may deduct (subtract) the increase (α) in the price (command value) from pr, thereby preventing the threshold from being changed relatively. As such, changing the threshold and changing the price value are relatively equivalent. Therefore, in this embodiment, a change (adjustment) in the threshold may be interpreted as a change (adjustment) in the price value, and conversely, a change (adjustment) in the price value may be interpreted as a change (adjustment) in the threshold.

[0052] The above is an example of the basic control method for charging device A. Fig. 6 shows the ON / OFF switching state and the transition of the adjustment range (threshold) before improvement (top diagram) and after improvement by this embodiment (bottom diagram). As shown in Fig. 6, by suppressing the decrease in threshold in the OFF state, i.e., the increase in priority, it is possible to prevent the priorities of multiple EVs from becoming too close to each other, and ultimately to prevent chattering.

[0053] Here, as mentioned above, if the switching from the power-off state (OFF) to the power-on state (ON) is suppressed, disadvantages (secondary issues) such as a slower charging speed or the inability to secure the required SOC by the time of departure may occur. Therefore, the following countermeasures may be taken.

[0054] <How to deal with secondary issues: Adjusting charging standby time> FIG. 7 shows the ON / OFF switching state (upper diagram) and the change state of the adjustment region (threshold) (lower diagram) when a countermeasure (setting method) for the secondary issue is implemented.

[0055] As an example of how to set the adjustment range, first determine the amount of change (slope) in the EV threshold when charging with 1 kW of power. Here, since we are just setting a standard, we will assume that "charging at 1 kW per 60 minutes will increase the threshold by 1."

[0056] Next, the hysteresis width is determined based on the amount of charge at one time when the battery is turned on. The finer the width, the more evenly the EVs are charged, but the number of times they are turned on and off increases. For example, if the battery is 3kWh (approximately 20km of driving distance), the width should be 3.

[0057] Then, the EV charging standby time T(>t) is determined taking into account the delay time (t) from when the EV is determined to be ON until current actually starts flowing. For example, the standby time T is set to 10 minutes, 20 times the delay time of 30 seconds, so that the hysteresis width is recovered in 10 minutes. It is also possible to set it so that if there is 10 minutes of excess electricity, equivalent to the power of one EV, the hysteresis width becomes 3, by saying, "If there is 1 kW of excess power per 60 minutes, it will increase by 3."

[0058] The above is an example of a setting method. In this way, by adjusting the hysteresis width, it is possible to give other charging devices a chance to charge and adjust the ON / OFF frequency. Furthermore, the delay time t, which is the time from when charging is determined to start until charging actually starts, varies between charging devices A. However, by setting a waiting time (T>t), this variation can be eliminated, preventing the priorities of the EVs from becoming too close, while also giving other EVs a chance to charge, thereby improving the reduction in charging speed.

[0059] <How to deal with secondary issues: hysteresis adjustment> Here, Figure 8 is a diagram showing an example of setting the adjustment range (threshold) when a method (setting method) for dealing with a secondary issue is taken, and Figure 9 is a diagram showing the ON / OFF switching state (upper diagram) and the changes in the adjustment range and price (lower diagram) when a method (setting method) for dealing with a secondary issue is taken.

[0060] The priority setting unit 119 increases the width of the hysteresis when it determines that the SOC will be insufficient until departure, i.e., when the time until departure is short or when the charging waiting time since the previous time is long (in this case, the charging stop SOC is essentially made to match that of the conventional example).

[0061] That is, as shown in Fig. 8, when it is determined that the SOC will be sufficient by the departure time, the priority setting unit 119 narrows the hysteresis width (the width above and below the threshold), while when it is determined that the SOC will be insufficient at the departure time, the priority setting unit 119 widens the hysteresis width (the width above and below the threshold) and extends the charging time. Fig. 9 shows an example in which it is determined that the SOC of a low-priority EV will be insufficient, and because the hysteresis width for the low-priority EV is set wide, the ON time is extended.

[0062] <Solution to secondary issue: tilt adjustment> Figures 10 and 11 show other examples of how to deal with secondary issues (gradient adjustment), and Figure 12 shows the ON / OFF switching state (upper figure) and the changes in the adjustment area and price (lower figure) when other examples of how to deal with secondary issues (gradient adjustment) are taken.

[0063] 10 and 11, if the priority setting unit 119 determines that the SOC will be insufficient by the time of departure, i.e., if the time until departure is short, or if the waiting time since the previous charge is long (in this case, the charging stop SOC is essentially made to match that of the conventional example), the priority setting unit 119 reduces the charging gradient (threshold increase rate). This allows the charging time of the corresponding EV to be extended.

[0064] As a further improvement, the following may be implemented. That is, even EVs in the same condition may have different priorities. For example, suppose there are two EVs that need to charge their remaining 7 kWh in two hours. EV1 arrived five hours ago needing 10 kWh, but decided that it had ample capacity and charged 3 kWh. On the other hand, EV2 arrived one hour ago needing 10 kWh, but decided that it did not have ample capacity and charged 3 kWh. In this case, EV1's threshold will be higher than EV2's, causing a problem. Therefore, as a further improvement, as shown in Figure 11, the priority setting unit 119 may decrease the slope when the threshold is greater than a reference threshold (standard threshold) determined taking into account time and SOC.

[0065] By adjusting the threshold increase rate using priority setting unit 119, as shown in FIG. 12, the slope (threshold increase rate) of low priority EVs can be made smaller, thereby ensuring a sufficient charge amount.

[0066] (Effects of this embodiment) As described above, according to this embodiment, the following advantageous effects can be obtained.

[0067] In this embodiment, charging device A, which can be switched between a powered state (ON) in which charging targets including a connected electric vehicle EV are charged, and a power-off state (OFF) in which charging is not performed, sets an adjustment range for ON / OFF switching according to the priority of switching to the powered state (ON), and determines whether to switch to the powered state (ON) or the power-off state (OFF) based on at least a command value pr sent from centralized control device F based on the target power value and the power demand of the entire system, and on the adjustment range. When the target power value and the power demand are close to each other, for example, when the amount of change α in command value pr is smaller than a predetermined value, charging device A is prohibited from determining whether to switch from the power-on state (OFF) to the power-on state (ON).

[0068] This makes it possible to prevent chattering, which occurs when a plurality of power control devices frequently switch between charging and non-charging, when the power demand of the entire system approaches the target power value.

[0069] Furthermore, according to this embodiment, the charging device A does not lower the threshold of the adjustment region when in a disconnected state (OFF), or deducts (subtracts) the amount of decrease in the threshold when in a disconnected state (OFF) from the command value pr.

[0070] This allows the priority for the command value pr to be determined without changing relative to the charging time, preventing chattering in the charging device due to priorities becoming closer between the time it is determined that another EV will charge and the time charging actually begins.

[0071] Furthermore, according to this embodiment, as a method (slope adjustment) for dealing with the secondary problem, the charging device A further adjusts the rate (slope) at which the threshold value of the adjustment region is increased when the power is on.

[0072] This allows, for example, a vehicle with a low priority to have a larger threshold increase rate (slope) and a charging device with a high priority to have a smaller slope, allowing the charging device with a high priority to charge for a longer period of time and charging devices with a low priority to charge for a shorter period of time, giving other charging devices a chance to charge. This can improve the decrease in charging speed that can occur when priority is not changed when not charging.

[0073] Furthermore, according to this embodiment, as a method for dealing with the secondary problem (hysteresis adjustment), the charging device A adjusts the width of the adjustment region when in a power-on state (ON).

[0074] This allows the hysteresis width to be widened as the priority increases, such as when the time until departure is short. This allows high-priority EVs to be charged for a longer period, while low-priority EVs are charged for a shorter period, giving other charging devices the opportunity to charge. This can alleviate the decrease in charging speed that can occur when priority is not changed when not charging.

[0075] Furthermore, according to this embodiment, as a method for addressing the secondary issue (adjusting the charging waiting time), the charging device A further adjusts the waiting time T until the start of power supply when it determines to switch to the power supply state (ON).

[0076] This allows a waiting time T to be set after determining that charging has started, giving other charging devices a chance to charge, and improving the decrease in charging speed that can occur when priority is not changed when not charging.

[0077] (Other embodiments) Although the embodiments of the present invention have been described above, the present invention may be implemented in various different embodiments other than those described above within the scope of the technical concept set forth in the claims.

[0078] For example, in the present embodiment, the case where charging device A charges electric vehicle B via charging cable 2 has been described, but the present invention is not limited to this. For example, charging device A may charge electric vehicle B using a contactless power transmission technology. That is, charging may be performed by magnetically coupling a power transmitting coil provided in charging device A with a power receiving coil provided in electric vehicle B, and supplying power from charging device A to electric vehicle B in a contactless manner. In this case, connection detection unit 14 may detect that the power receiving coil of electric vehicle B has entered a range where it can receive power from the power transmitting coil of charging device A.

[0079] In this embodiment, the case where charging device A communicates with electric vehicle B to receive the charging rate and storage battery capacity has been described, but this is not limiting. If charging device A does not have a function for communicating with electric vehicle B, the user of electric vehicle B may manually input the storage battery capacity and current charging rate by operating an operation means (not shown) of charging device A. In this case, charging device A may update the charging rate from the storage battery capacity and charging power as needed during charging.

[0080] In this embodiment, the case where charging device A charges electric vehicle B has been described, but this is not limiting. Instead of electric vehicle B, charging device A may charge vehicles such as two-wheeled vehicles (electric motorcycles, electrically assisted bicycles) equipped with an electric motor as a power source, and automated guided vehicles.

[0081] In the present embodiment, the power system G is described as including power conditioners C1-Cn connected to solar cells and power conditioners D1-Dm connected to storage batteries, but this is not limiting. The power system G may not include power conditioners C1-Cn or power conditioners D1-Dm. Furthermore, the power system G may include other power devices, and the centralized management device F may include these power devices in its management targets.

[0082] Furthermore, the charging device and power system according to the present invention are not limited to the above-described embodiments. The specific configurations of each part of the charging device and power system according to the present invention can be freely designed and modified in various ways. Furthermore, the specific form of distribution and integration of the devices is not limited to those shown in the drawings, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various additions or functional loads. In other words, the above-described embodiments can be implemented in any combination, or embodiments can be implemented selectively. [Explanation of symbols]

[0083] A: Charging device 111: Judgment index calculation unit 119:Priority setting part 112: Judgment Department 12: Switch 14: Connection detection unit B: Electric vehicle F: Centralized control device G: Power Systems

Claims

1. A charging device that can be switched between a powered state in which a charging target including a connected electric vehicle is charged and a powered-off state in which charging is not performed, a switch that switches between the energized state and the non-energized state; a priority setting unit that sets an adjustment range of the switching according to the priority of the energized state; a determination unit that determines whether to put the power supply into the energized state or the non-energized state based on at least a command value transmitted from a centralized control device based on a target power value and the power demand of the entire system, and based on the adjustment area; When the target power value and the power demand are close to each other, the determination unit is prohibited from determining whether to switch from the non-conductive state to the conductive state. Charging device.

2. The priority setting unit does not lower the threshold of the adjustment region when the communication is interrupted, or The determination unit subtracts the decrease in the threshold value when the communication is interrupted from the command value. The charging device according to claim 1 .

3. The priority setting unit further adjust the rate at which the threshold value of the adjustment region is increased in the energized state 3. The charging device according to claim 1 or 2.

4. The priority setting unit further adjust the width of the adjustment region in the energized state 4. The charging device according to claim 1.

5. The determination unit further When it is determined to switch to the energized state, the waiting time until energization starts is adjusted.

5. The charging device according to claim 1.

6. A plurality of charging devices according to any one of claims 1 to 5; the centralized control device that outputs the common command value to each of the charging devices; An electric power system comprising:

7. A charging method executed in a charging device that can be switched between a powered state in which a charging target including a connected electric vehicle is charged and a powered-off state in which charging is not performed, a priority setting step of setting an adjustment range of the switching according to the priority of the energized state; a determination step of determining whether to put the power supply into the energized state or the non-energized state based on at least a command value transmitted from a centralized control device based on a target power value and the power demand of the entire system, and based on the adjustment area; When the target power value and the power demand are close to each other, the determination of switching from the non-conductive state to the conductive state is prohibited in the determination step. Charging method.

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