Power control system and power control method

Abstract

To provide an electric power control system and an electric power control method capable of adjusting an electric power balance of a power transmission network utilizing an electric vehicle parked in a parking facility.SOLUTION: An electric power control system 1 comprises: a plurality of parking facilities 3 connected with a power transmission network 2; a monitoring device 4 monitoring a frequency F of a voltage in the power transmission network 2; and a control device 6 connected with the monitoring device 4 and the plurality of parking facilities 3 via a communication network 5 so as to communicate. The control device 6 is configured to: output a charging command for instructing to charge a parked electric vehicle 8 to the parking facility 3 when the frequency F of the voltage in the power transmission network 2 is higher than a target frequency Ft; and output a discharging command for instructing to discharge the parked electric vehicle 8 to the parking facility 3 when the frequency F of the voltage in the power transmission network 2 is lower than the target frequency Ft.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electric power control system and an electric power control method, and more particularly to an electric power control system and an electric power control method that utilize a parking facility capable of parking an electric vehicle. [Background technology]

[0002] In recent years, electric vehicles (EVs), which use electricity as their energy source and are powered by electric motors, are becoming more and more popular. Hybrid vehicles (HVs), which use an internal combustion engine (engine) as a power source in addition to an electric motor, are also becoming more and more popular. Hereinafter, in this specification, "electric vehicle" includes both electric vehicles (EVs) and hybrid vehicles (HVs).

[0003] Current electric vehicles generally have a secondary battery (storage battery) that can be charged from an external power source, and are driven by an electric motor that is supplied with electricity from the secondary battery. As such electric vehicles become more widespread, multiple electric vehicles will be parked in parking facilities.

[0004] For example, the invention described in Patent Document 1 takes into consideration that the total amount of power that can be output from the batteries built into multiple electric vehicles is equivalent to the power required to operate a parking device, and discloses drawing power from parked electric vehicles and supplying it to the parking device and a power grid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-42634 A Summary of the Invention [Problem to be solved by the invention]

[0006] The invention described in the above-mentioned Patent Document 1 is characterized by how charged electric power is drawn from electric vehicles parked in each parking device. The invention described in Patent Document 1 includes a host controller connected to a power transmission network, and describes that the controller communicates various communication contents to the parking device based on the power supply and demand balance of the power transmission network.

[0007] However, the invention described in Patent Document 1 does not disclose how to determine the supply and demand balance of electricity in the power transmission network, or how to control multiple parking devices based on that supply and demand balance.

[0008] The present invention has been devised in consideration of these problems, and has an object to provide a power control system and a power control method that are capable of adjusting the power balance of a power transmission grid by using electric vehicles parked in a parking facility. [Means for solving the problem]

[0009] According to the invention, a system is provided comprising a plurality of parking facilities connected to a power grid, The frequency of the voltage of the grid is and a control device communicatively connected to the plurality of parking facilities and the monitoring device, each of the parking facilities including a power source capable of charging a parked electric vehicle, and a charge / discharge control device that controls charging or discharging of the electric vehicle, the control device including: When the frequency of the voltage of the power grid is higher than the target frequency, outputting a charging command to the parking facility to instruct the parking facility to charge the parked electric vehicle; When the frequency of the voltage of the power grid is lower than the target frequency, The present invention provides a power control system that is configured to output a discharge command to the parking facility to instruct the parking facility to discharge the electric vehicle parked therein, and to set priorities for charging or discharging based on a charging rate or a charging capacity of the plurality of parking facilities.

[0011] The control device may be configured to output a termination command to terminate charging or discharging of the electric vehicle when a frequency of a voltage of the power grid approaches a target frequency.

[0012] The charge / discharge control device may be configured to terminate charging or discharging when a charging rate reaches a preset value. Also, the charge / discharge control device may be configured not to fully charge the electric vehicle that is parked.

[0013] Further, according to the present invention, Based on fluctuations in the frequency of the grid voltage A power control method for charging or discharging electric vehicles parked in a plurality of parking facilities, comprising: When the frequency of the voltage of the power grid is higher than the target frequency, Charging the electric vehicle parked in the parking facility; When the frequency of the voltage of the power grid is lower than the target frequency, The present invention provides a power control method, characterized in that the electric vehicles parked in the parking facilities are discharged, and priorities for charging or discharging are set based on the charging rates or charging capacities of the plurality of parking facilities.

[0015] The power control method may terminate charging or discharging of the electric vehicle when a frequency of a voltage of the power grid approaches a target frequency. Also, the power control method may terminate charging or discharging of the electric vehicle when a charging rate of the parking facility reaches a preset value. Effect of the Invention

[0016] According to the power control system and power control method of the present invention described above, an electric vehicle parked in a parking facility is charged or discharged based on fluctuations in the frequency of the voltage of the power transmission network, so that the electric vehicle parked in the parking facility can be used to adjust the power balance of the power transmission network. [Brief description of the drawings]

[0017] [Figure 1] 1 is an overall configuration diagram showing a power control system according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a diagram illustrating an example of a control flow of a control device. [Diagram 3] FIG. 11 is a diagram illustrating an example of a method for setting a priority order of a control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to Fig. 1 to Fig. 3. Here, Fig. 1 is an overall configuration diagram showing a power control system according to an embodiment of the present invention. Fig. 2 is a diagram showing an example of a control flow of a control device.

[0019] A power control system 1 according to one embodiment of the present invention includes, for example, as shown in FIG. 1, a plurality of parking facilities 3 connected to a power transmission network 2, a monitoring device 4 that monitors the frequency F of the voltage of the power transmission network 2, and a control device 6 that is communicatively connected to the monitoring device 4 and the plurality of parking facilities 3 via a communication network 5.

[0020] The power transmission network 2 is, for example, a three-phase 6.6 KV AC commercial power network. The power transmission network 2 is, for example, a power system with a frequency of 50 Hz (Eastern Japan) or a power system with a frequency of 60 Hz (Western Japan). Therefore, when the power transmission network 2 is a power system with a frequency of 50 Hz, the target voltage frequency is 50 Hz, and when the power transmission network 2 is a power system with a frequency of 60 Hz, the target voltage frequency is 60 Hz. In addition, a power plant 7, which is a power supply source, is connected to the power transmission network 2.

[0021] The parking facility 3 is a parking facility where the parked electric vehicle 8 can be charged. The parking facility 3 may be a self-propelled parking device or a mechanical parking device as long as it is capable of charging. The parking facility 3 may be a home parking facility capable of accommodating only one vehicle, or a large-scale parking facility capable of accommodating 100 vehicles or more. The electric vehicle 8 is, for example, an electric vehicle (EV) or a hybrid vehicle (HV).

[0022] 1, for ease of explanation, the embodiment illustrates a case in which four parking facilities 3, a first parking facility 31, a second parking facility 32, a third parking facility 33, and a fourth parking facility 34, are connected to the power transmission network 2. Note that the more parking facilities 3 connected to the power transmission network 2, the better, and ideally the number of parking facilities 3 connected to the power transmission network 2 should be on the scale of hundreds of thousands or millions of vehicles.

[0023] The first parking facility 31 to the fourth parking facility 34 are equipped with, for example, power sources 31a to 34a capable of charging the parked electric vehicles 8, and charge / discharge control devices 31b to 34b that control the charging or discharging of the electric vehicles 8.

[0024] The power sources 31a to 34a are storage batteries installed in each of the first to fourth parking facilities 31 to 34, and are connected to the power grid 2. The power sources 31a to 34a are equipped with a converter that converts AC voltage supplied from the power grid 2 to DC voltage. The power sources 31a to 34a are also equipped with an inverter that converts electricity from DC voltage to AC voltage and supplies it to the power grid 2.

[0025] The charge / discharge control devices 31b-34b are connected to the communication network 5 and have functions such as a function of maintaining a constant charge amount of the power sources 31a-34a, a function of supplying electricity from the power sources 31a-34a to the parked electric vehicle 8 to charge the electric vehicle 8, and a function of supplying electricity stored in the secondary battery (storage battery) of the parked electric vehicle 8 to the power transmission network 2 via the power sources 31a-34a.

[0026] Note that the specific configuration for charging electric vehicles 8 at each parking facility 3 and the specific configuration for supplying electricity from electric vehicles 8 to the power grid 2 are described in, for example, JP 2013-42634 A (Patent Document 1), and therefore detailed explanations will be omitted in this specification.

[0027] The monitoring device 4 is a sensor that monitors whether the frequency F of the voltage of the power transmission network 2 is higher than the target frequency Ft or whether the frequency F of the voltage of the power transmission network 2 is lower than the target frequency Ft. The frequency F measured by the monitoring device 4 is transmitted to the control device 6 via a communication network 5. The communication network 5 is a communication network capable of mutual data communication, such as the Internet.

[0028] Incidentally, it is known that the frequency F of the voltage of the power grid 2 is determined by the balance between demand (load) and supply (power generation). For example, if the supply (power generation) is large, the frequency tends to be high, and if the demand (load) is large, the frequency tends to be low. Since the demand (load), which is the amount of electricity used, is constantly fluctuating, the frequency F of the voltage of the power grid 2 is also constantly fluctuating.

[0029] Power companies adjust the amount of power generation so that the amount of fluctuation in this frequency F is within ±0.1 to ±0.2 Hz of the target frequency (50 Hz or 60 Hz). This adjustment of the amount of power generation is performed by power plants 7 in the power grid 2. Since power plants 7 are usually thermal power plants, an increase in the amount of power generation means an increase in the amount of fuel used, which leads to an increase in the amount of carbon dioxide generated.

[0030] The power control system 1 according to this embodiment utilizes electric vehicles 8 parked in a plurality of parking facilities 3 as a means for adjusting the amount of fluctuation in frequency F to within ±0.1 to ±0.2 Hz of a target frequency (50 Hz or 60 Hz).

[0031] In this way, by using the electricity charged in the electric vehicle 8 as part of the social infrastructure, the amount of fuel used at thermal power plants and the amount of carbon dioxide produced can be reduced, thereby improving the added value of the electric vehicle 8.

[0032] The control device 6 is configured to output a charging command to the parking facility 3 to instruct the parking facility 3 to charge the parked electric vehicle 8 when the frequency F of the voltage of the power transmission network 2 is higher than the target frequency Ft, based on the signal (measurement result) transmitted from the monitoring device 4, and to output a discharging command to the parking facility 3 to instruct the parking facility 3 to discharge the parked electric vehicle 8 when the frequency F of the voltage of the power transmission network 2 is lower than the target frequency Ft.

[0033] The control device 6 controls the charging and discharging of the electric vehicle 8 based on, for example, the control flow shown in Fig. 2. The frequency F of the voltage of the power grid 2 is periodically monitored by the monitoring device 4 (monitoring step Step 1). Then, the control device 6 judges whether the frequency F measured by the monitoring device 4 is higher or lower than the target frequency Ft (first judgment step Step 2).

[0034] If it is determined in the first determination step Step 2 that F>Ft, this means that there is a surplus of power because the supply (amount of power generation) is greater than the demand (amount of load). Therefore, the control device 6 outputs a charging command to the parking facility 3 to instruct the parking facility 3 to charge the parked electric vehicle 8 (charging command step Step 3).

[0035] The parking facility 3 (for example, the first parking facility 31 to the fourth parking facility 34) that has received the charging command charges the parked electric vehicle 8 using the charge / discharge control devices 31b to 34b (charging step Step 4).

[0036] The control device 6 judges whether the frequency F measured by the monitoring device 4 approaches the target frequency Ft (second judgment step Step 5). Whether the frequency F approaches the target frequency Ft may be judged based on whether the measured frequency F reaches the target frequency Ft, or may be judged based on whether the measured frequency F reaches a range having a certain width with respect to the target frequency Ft (for example, a range within ±0.1 Hz with respect to the target frequency Ft).

[0037] If the control device 6 determines that the frequency F is not yet approaching the target frequency Ft (No), it continues charging the electric vehicle 8, and if it determines that the frequency F is approaching the target frequency Ft (Yes), it outputs an end command to the parking facility 3 to instruct it to end the charging of the electric vehicle 8 (charging end command step Step 6).

[0038] The parking facilities 3 (for example, the first parking facility 31 to the fourth parking facility 34) that have received the end command end the charging of the parked electric vehicles 8 by the charge / discharge control devices 31b to 34b (charging end step Step 7). Note that the charge / discharge control devices 31b to 34b may end the charging of the electric vehicles 8 without waiting for the end command from the control device 6 when the charging rates of all the parked electric vehicles 8 reach a preset value (for example, any value within a range of 80 to 100%).

[0039] On the other hand, in the first determination step (Step 2), if it is determined that F < Ft, it means that the power supply (generation amount) is small relative to the demand (load amount), indicating a shortage of power. Therefore, the control device 6 outputs a discharge command instructing the parked electric vehicles 8 in the parking facility 3 to discharge (discharge command step, Step 8).

[0040] Upon receiving the discharge command, the parking facility 3 (for example, the first parking facility 31 to the fourth parking facility 34) discharges the parked electric vehicles 8 by the charge / discharge control devices 31b to 34b and supplies electricity to the power grid 2 (discharge step, Step 9).

[0041] The control device 6 determines whether the measured frequency F approaches the target frequency Ft (third determination step, Step 10). Whether the frequency F approaches the target frequency Ft may be determined by whether the measured frequency F reaches the target frequency Ft, or may be determined by whether the measured frequency F reaches a range having a certain width with respect to the target frequency Ft (for example, a range within ±0.1 Hz with respect to the target frequency Ft).

[0042] When the control device 6 determines that the frequency F has not yet approached the target frequency Ft (No), it continues the discharge of the electric vehicle 8. When it determines that the frequency F has approached the target frequency Ft (Yes), it outputs an end command instructing the end of the discharge of the electric vehicle 8 to the parking facility 3 (discharge end command step, Step 11).

[0043] Upon receiving the end command, the parking facility 3 (for example, the first parking facility 31 to the fourth parking facility 34) ends the discharge of the parked electric vehicles 8 by the charge / discharge control devices 31b to 34b (discharge end step, Step 12). Note that the charge / discharge control devices 31b to 34b may end the discharge of the electric vehicles 8 without waiting for the end command from the control device 6 when the charge rates of all the parked electric vehicles 8 reach a preset value (for example, any value within the range of 0 to 20%).

[0044] According to this control flow, the electric vehicle 8 parked in the parking facility 3 can be charged or discharged based on the fluctuation of the frequency F of the voltage of the power transmission network 2. Furthermore, by using the above-mentioned control flow, when the frequency F of the voltage of the power transmission network 2 is higher than the target frequency Ft, the electric vehicle 8 parked in the parking facility 3 can be charged, and when the frequency F of the voltage of the power transmission network 2 is lower than the target frequency Ft, the electric vehicle 8 parked in the parking facility 3 can be discharged.

[0045] According to the power control system 1 and power control method of the present embodiment described above, the electric vehicle 8 parked in the parking facility 3 is charged or discharged based on fluctuations in the frequency F of the voltage of the power transmission network 2, so that the electric vehicle 8 parked in the parking facility 3 can be used to adjust the power balance of the power transmission network 2.

[0046] In the above-described embodiment, the instruction to charge or discharge is output to all the parking facilities 3 (for example, the first parking facility 31 to the fourth parking facility 34), but the instruction may be output by setting a priority order for charging or discharging based on the charging rate or charging capacity of the parking facilities 3. Here, Fig. 3 is a diagram showing an example of a method for setting the priority order by the control device.

[0047] For ease of explanation, let us assume that the first parking facility 31 can accommodate 50 cars, the second parking facility 32 can accommodate 30 cars, the third parking facility 33 can accommodate 30 cars, and the fourth parking facility 34 can accommodate 10 cars.

[0048] In addition, if the battery capacity of the electric vehicle 8 is 50 kWh, the total battery capacity of the first parking facility 31 is 2500 kWh, the total battery capacity of the second parking facility 32 is 1500 kWh, the total battery capacity of the third parking facility 33 is 1500 kWh, and the total battery capacity of the fourth parking facility 34 is 500 kWh.

[0049] Here, as shown in Fig. 3, if the charging rate of the first parking facility 31 is 30%, the charging capacity is 750 kWh and the available capacity is 1750 kWh. If the charging rate of the second parking facility 32 is 50%, the charging capacity is 750 kWh and the available capacity is 750 kWh. If the charging rate of the third parking facility 33 is 80%, the charging capacity is 1200 kWh and the available capacity is 300 kWh. If the charging rate of the fourth parking facility 34 is 100%, the charging capacity is 500 kWh and the available capacity is 0 kWh.

[0050] Information such as the charging rate of each parking facility 3 (first parking facility 31 to fourth parking facility 34) and the number of parked electric vehicles 8 is periodically transmitted from the charge / discharge control devices 31b to 34b to the control device 6 via the communication network 5.

[0051] In this state, when outputting a charging command from the control device 6, the priority may be set in the order of parking facilities 3 with the largest free battery capacity, and the charging command may be output. In the first example shown in Fig. 3, the free capacity has the following relationship: first parking facility 31>second parking facility 32>third parking facility 33>fourth parking facility 34, so the priority is set in the order of first parking facility 31→second parking facility 32→third parking facility 33→fourth parking facility 34. Note that a charging command may not be output to the fourth parking facility 34, which has no free battery capacity.

[0052] Furthermore, when the control device 6 outputs a discharge command, the priority may be set in the order of the parking facilities 3 having the largest battery charge capacity, and the discharge command may be output. In the first example shown in Fig. 3, the relationship of charge capacity is third parking facility 33>second parking facility 32=first parking facility 31>fourth parking facility 34.

[0053] In this case, if the charging capacities are the same, the priority may be set to the one with the higher charging rate, for example. Therefore, during discharging, the priority is set in the following order as shown in the figure: third parking facility 33 → second parking facility 32 → first parking facility 31 → fourth parking facility 34.

[0054] In the power control system according to this embodiment, charging and discharging of the electric vehicle 8 is performed according to the power balance of the power transmission network 2, so when the parked electric vehicle 8 is fully charged (charging rate 100%), it is not possible to respond to a charging command from the control device 6. Therefore, the charge and discharge control devices 31b to 34b may be configured not to fully charge the parked electric vehicle 8. For example, the upper limit of the charging rate of the electric vehicle 8 can be set to 80%.

[0055] The power control system 1 according to the present embodiment described above utilizes the batteries of the electric vehicles 8 for social infrastructure based on the power balance of the power grid 2, and therefore requires the understanding and cooperation of the owners of the electric vehicles 8. Therefore, the parking facility 3 is preferably a monthly parking facility where users are identified and where regular parking for a fixed period of time is expected.

[0056] However, the power control system 1 of this embodiment is not limited to monthly parking facilities, and can also be widely applied to parking facilities in commercial facilities, companies, etc., by taking measures such as reducing parking fees.

[0057] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0058] 1. Power Control System 2. Power grid 3. Parking facilities 4 Monitoring device 5. Communication Network 6. Control device 7. Power Plant 8 Electric Vehicles 31 First Parking Facility 32 Second Parking Facility 33 Third Parking Facility 34 Fourth Parking Facility 31a~34a Power supply 31b~34b Charge / discharge control device Step 1: Monitoring step Step 2: Decision making Step 2: First decision step Step 3: Charging command step Step 4 Charging step Step 5: Second decision step Step 6: Charge end command step Step 7: Charging end step Step 8 Discharge command step Step 9 Discharge step Step 10: Third decision step Step 11 Discharge end command step Step 12 Discharge end step

Claims

1. a plurality of parking facilities connected to an electric grid; a monitoring device for monitoring the frequency of the voltage of the power grid; a control device communicatively connected to the plurality of parking facilities and the monitoring device; Each of the parking facilities includes a power source capable of charging a parked electric vehicle, and a charge / discharge control device that controls charging or discharging of the electric vehicle; The control device is configured to output a charging command to the parking facility to instruct the parking facility to charge the electric vehicle parked therein when a frequency of the voltage of the power transmission network is higher than a target frequency, and to output a discharging command to the parking facility to instruct the parking facility to discharge the electric vehicle parked therein when a frequency of the voltage of the power transmission network is lower than a target frequency, and to set a priority order for charging or discharging based on a charging rate or a charging capacity of the plurality of parking facilities. A power control system comprising:

2. The power control system according to claim 1 , wherein the control device is configured to output a termination command to terminate charging or discharging of the electric vehicle when a frequency of a voltage of the power grid approaches a target frequency.

3. The power control system according to claim 1 , wherein the charge / discharge control device is configured to terminate charging or discharging when a charging rate reaches a preset value.

4. The power control system according to any one of claims 1 to 3, wherein the charge / discharge control device is configured not to fully charge the electric vehicle that is parked.

5. A power control method for charging or discharging electric vehicles parked in a plurality of parking facilities based on fluctuations in the frequency of a voltage of a power grid, comprising: charging the electric vehicle parked in the parking facility when a frequency of the voltage of the power grid is higher than a target frequency, and discharging the electric vehicle parked in the parking facility when a frequency of the voltage of the power grid is lower than a target frequency; A priority order for charging or discharging is set based on the charging rate or charging capacity of the plurality of parking facilities.

2. A power control method comprising:

6. The power control method according to claim 5 , further comprising terminating charging or discharging of the electric vehicle when a frequency of a voltage of the power grid approaches a target frequency.

7. 6. The power control method according to claim 5, further comprising the step of terminating charging or discharging of the electric vehicle when a charging rate of the parking facility reaches a preset value.

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