JP7680320B2 - Power management system and power management method - Google Patents

Description

This disclosure relates to a power management system and a power management method.

As electric vehicles (EVs) become more widespread, it has become necessary to charge them using the power source at individuals' homes. The charging power required for EVs is greater than the power consumed by home appliances, etc., because rapid charging is required. This results in higher peak power received by homes, making it necessary to increase the contracted power, raising concerns about an increase in basic charges.

In addition, from the perspective of utilizing renewable energy and saving energy, the spread of HEMS (Home Energy Management System) and BEMS (Building Energy Management System) is being promoted.

Patent Document 1 assumes that when a large-capacity storage battery, such as that used in electric vehicles, is rapidly charged while various types of home appliances are in use, a large current may flow and exceed the contracted power capacity. It discloses that the load current supplied to the home appliance is measured, and the appropriate charging current for the storage battery is calculated within a range that does not exceed the maximum allowable load current calculated from the contracted power capacity for the received power when the measured load current is added to the charging current of the storage battery, and the storage battery is charged with the appropriate charging current, and the appropriate charging current for the storage battery is recalculated and the charging current for the storage battery is changed every time the measured load current changes by a certain amount or more. Patent Document 1 also discloses that a HEMS management server is provided that monitors the usage status of the home appliances and automatically turns the home appliances on and off according to a preset energy usage standard to control their energy usage, and that when the HEMS management server automatically turns on any of the home appliances, charging of the storage battery is temporarily suspended, and the suspension time can be, for example, about one minute.

Patent document 2 discloses that when a charging device is installed together with high-voltage power receiving equipment such as store equipment, if the predicted value of the total amount of power received from the system power source 99, including the amount of power required by the battery-equipped device 114, is greater than a preset upper limit, an output command value from the power conversion unit 106 is calculated that allows the battery-equipped device 114 to be charged within a range in which the total amount of power received from the system power source 99 does not exceed the upper limit.

Patent Document 3 discloses an electric vehicle charging power management system that detects the power to the electric load in the home and controls the charging power so that the sum of the detected power and the charging power to the battery does not exceed the allowable value of the power supplied from the outside to the home in order to prevent the total power load of the home from exceeding the maximum contract power while the battery of the electric vehicle is being charged. The system calculates the expected power consumption in the home for a specified time period based on the power consumption history information of the electric load in the home, compares the power obtained by subtracting the expected power consumption in the home from the allowable value, the charging request power value from the electric vehicle side, and the power obtained by subtracting the detected power from the allowable value, and sets the lowest power as the charging power. Cited Document 3 also discloses that the charging request power value WVd read from the battery controller 31 is determined to be less than the value (WA-WH) obtained by subtracting the home power load value WH from the maximum contract power WA, which is the power allowable value on the home side, and sets the charging power WV to WV=WA-WH so that the breaker of the home does not trip if it is determined that the charging request power value WVd is equal to or greater than (WA-WH).

JP 2012-191773 A JP 2014-023204 A JP 2008-136291 A

The battery charging control system described in Patent Document 1 recalculates the appropriate charging current for the battery and changes the charging current for the battery every time the measured load current changes by a certain amount or more. However, recalculating the appropriate charging current for the battery requires a certain amount of time, and there is room for improvement in that there is a risk that the system cannot fully respond to changes in the load current.

In the charging device described in Patent Document 2, all of the received power is used to charge the battery of an EV, which is assumed to be a battery-equipped device, so it is relatively easy to predict the required amount of power. It is considered difficult to apply this charging device in conditions where it is not possible to predict changes in power consumption in advance, such as with home appliances, etc.

The electric vehicle charging power management system described in Patent Document 3 requires a large amount of known data to calculate the predicted power consumption within the home and to compare power using the charging request power value, etc., and the detection of power to the home's power load does not take into account sudden changes in power due to starting and stopping the home's power load, etc.

The purpose of this disclosure is to continue charging an electric vehicle and keep the received power within the range of the contracted power even when the power consumption of loads such as home appliances suddenly increases.

The power management system disclosed herein manages the received power supplied from a commercial power source to a building load and a vehicle storage battery, and includes a received power detection unit that detects the received power from the commercial power source, a calculation unit, a load operation signal detection unit that detects a load operation signal of the load, and a control unit. When the load operation signal detection unit detects a load operation signal, the calculation unit calculates the difference between the upper limit of the received power and the load power, which is the total value of the power consumption of the load including the change in power consumption of the load that issued the load operation signal, and calculates the value of the charging power to be supplied to the storage battery with this difference as the maximum value. The control unit charges the storage battery with the charging power, and then causes the load that issued the load operation signal to operate in accordance with the load operation signal.

According to this disclosure, even when the power consumption of loads such as home appliances increases sharply, it is possible to continue charging an electric vehicle and keep the received power within the range of the contracted power.

FIG. 1 is a schematic configuration diagram showing a power management system according to an embodiment. 2 is a graph showing an example of control by the power management system 10 of FIG. 1 . FIG. 2 is a configuration diagram showing details of the power management system 10 of FIG. 1. FIG. 4 is a flow diagram illustrating a power management method of an embodiment.

The following describes an embodiment of this disclosure with reference to the drawings.

Figure 1 is a schematic diagram showing the power management system of the embodiment.

In this diagram, the power management system 10 is a system that manages the power of a commercial power source 100 used in a house 20 (including a residence or a building). Loads 22, 24 (home appliances, etc.) are installed inside or outside the house 20. The loads 22, 24 are supplied with power from the commercial power source 100. The home appliances include air conditioners, heat pump water heaters, induction cooking heaters, microwave ovens, electric rice cookers, electric kettles, hair dryers, etc. Among these, an induction cooking heater will be taken as an example below of equipment that is started and stopped (on/off) by a manual switch.

The electric vehicle 30 (EV) placed in a parking space of the house 20 or the like has a built-in storage battery (secondary battery) and charger 35. The storage battery of the electric vehicle 30 is supplied with power from the commercial power source 100 via the charger 35. In this embodiment, it is assumed that the loads 22, 24 and the charger 35 are supplied with power through wiring branched off from a single ampere breaker.

In this embodiment, the power management system 10 includes the functions of a HEMS. Note that the power management system 10 may be installed separately from the HEMS.

The power management system 10 has a function to detect the power actually being supplied from the commercial power source 100. The power management system 10 also has a function to detect the power actually being supplied to the loads 22, 24 and the storage battery of the electric vehicle 30, and a function to detect the load operation signals of the loads 22, 24. Furthermore, the power management system 10 has a function to start supplying power to the loads 22, 24.

Figure 2 is a graph showing an example of control by the power management system 10 of Figure 1.

Figure 2 shows the changes over time for four things: received power from a commercial power source, charging power supplied to the EV's storage battery, load power (total power consumption of home appliances, etc.), and load operation signal. Here, the load operation signal refers to a signal that an appliance emits when some of the appliances start or stop. An example of a load operation signal is the start/stop of an air conditioner. The start/stop of an air conditioner may be performed automatically by the HEMS. The load operation signal is also emitted when the power consumption of the appliance increases or decreases.

As shown in the figure, when a stopped home appliance starts up and a load operation signal is issued, the power management system 10 (Figure 1) sends a signal to the charger 35 to reduce the charging power supplied to the EV's storage battery. This reduces the charging power (represented by (1) in the figure). Next, the power management system 10 issues a signal to permit the supply of power to the home appliance that issued the load operation signal. This starts the supply of power to the home appliance that issued the load operation signal, and the home appliance starts up (represented by (2) in the figure). As a result of (1) and (2) above, the received power of the house 20 (Figure 1) fluctuates.

The received power is controlled so that it always remains below the upper limit shown by the dashed line on the graph. This upper limit must be set below the contracted power.

Figure 3 is a configuration diagram showing details of the power management system 10 in Figure 1.

As shown in FIG. 3, the power management system 10 includes a received power detection unit 12, a calculation unit 14, a load operation signal detection unit 16, and a control unit 18.

The receiving power detection unit 12 detects the receiving power from the commercial power source 100 (Figure 1).

The load operation signal detection unit 16 detects load operation signals of home appliances and the like. Here, the load operation signal detection unit 16 detects the load operation signal in a shorter time than the operation of an ampere breaker provided in the switchboard. The load operation signal detection unit 16 has an electrical circuit for this purpose. The load operation signal may be an electrical signal such as a pulse that is specially emitted when the load automatically starts or stops, an optical signal such as infrared light, or the very initial change in current or voltage when the load starts or stops. When an optical signal is used, an optical sensor such as an infrared sensor that can receive the signal is installed in a position where it can receive the signal.

The calculation unit 14 receives specific data from the received power detection unit 12 and the load operation signal detection unit 16, and calculates the value of the charging power to be supplied to the EV's storage battery.

Based on the data from the calculation unit 14, the control unit 18 sends a set value for the charging power to the EV charger and sends start/stop control signals to loads such as home appliances.

Next, we will explain how to manage the received power in the power management system 10 of Figure 3 so that it is below a predetermined upper limit.

Figure 4 is a flow diagram showing the power management method of the embodiment.

As shown in this figure, the receiving power detection unit 12 detects the receiving power (step S100).

The load operation signal detection unit 16 detects a signal from the load (step S110).

If the signal from the load is a load start signal, the calculation unit 14 calculates the difference between the contracted power or a predetermined upper limit of power and the load power (step S120). Here, the load power is the total value of the power consumption of all the loads, including the change in the power consumption of the load that issued the load operation signal.

Furthermore, the calculation unit 14 calculates the charging power for the EV's storage battery using the above difference as the upper limit (maximum value) (step S130).

The control unit 18 reduces the charging power of the EV's storage battery (step S140).

Thereafter, the control unit 18 starts supplying power to the load that has issued the load operation signal as the above signal (step S150). The time from detecting the signal from the load to starting the supply of power to the load should be as short as possible so that the occupants do not find the delay in the operation of the load unpleasant, and it is desirable to set it to within 0.5 seconds, for example.

In the example shown in this figure, the load is started, but when the load is stopped, the load operation signal detection unit 16 detects a stop signal from the load, and then the calculation unit 14 calculates the difference between the contracted power or a predetermined upper limit value of the power and the load power, and the control unit 18 calculates the charging power of the EV's storage battery using this difference as the upper limit value (maximum value), and increases the charging power.

In addition, if the load is an appliance that is started and stopped (on/off) by a manual switch, such as an induction cooking heater, the change in voltage or current associated with starting and stopping is detected by the load operation signal detection unit 16. In addition, the induction cooking heater may be provided with a function that emits a special electrical signal such as a pulse when the manual switch of the induction cooking heater is turned on by the resident.

In the case of an induction cooking heater, an example corresponding to steps S120 to S150 above may be to set the time from pressing the heating button on the induction cooking heater to reducing the charging power of the EV's storage battery and starting to supply power to the load to, for example, about 0.5 seconds.

Furthermore, even if the occupant changes the power consumption of the load by a method other than turning it on and off, such as changing the temperature setting of the air conditioner or the heat output of the induction cooking heater, the load operation signal detection unit 16 detects the load operation signal that indicates a change in voltage or current, and changes the charging power of the EV's storage battery. In this case, too, a special electrical signal may be issued from the load side.

Note that manual operation also includes operation using a remote control (remote control device) for air conditioning equipment, etc.

In addition, when operating with voice recognition to give voice instructions to start/stop home appliances, change output, etc., the load operation signal detection unit 16 may detect a signal from the load and use it to change the charging power, just as in manual operation.

The power management system 10 also preferably has a memory unit that records and accumulates past data such as received power, load power, and charging power, and has a function of learning by recording and accumulating the amount of change in the power consumption of the load due to the start-up of the load, changes in power consumption, etc. It is also preferable that the power management system 10 has a function of predicting how much the charging power of the EV's storage battery should be changed using the results of such learning.

In addition, if charging the EV's storage battery is a priority, the power supply to the load may be restricted. In this case, the power supplied to the load is adjusted so that the sum of the load power and the charging power is equal to or less than the upper limit of the received power.

The supply of power to a load may be started by sending a signal to the load to allow it to operate, or by providing a power switching switch inside the power management system 10 and automatically switching the switch upon receiving a signal from the control unit 18. The same applies when changing the power consumption of the load.

In summary, when the load operation signal detection unit detects a load operation signal, the calculation unit calculates the difference between the upper limit of the received power and the load power, which is the total value of the power consumption of the load including the change in the power consumption of the load that issued the load operation signal, and calculates the value of the charging power to be supplied to the storage battery with this difference as the maximum value. Then, the control unit charges the storage battery with the charging power, and then causes the load that issued the load operation signal to operate according to the load operation signal. If the load power exceeds the upper limit of the received power and further exceeds the contracted power, the breaker will trip. For this reason, the load power is limited to be equal to or less than the upper limit of the received power. This role may be played by the power management system. In addition, in order to avoid the breaker tripping and to maintain the charging power at a predetermined value or more, it is desirable to make the upper limit of the received power smaller than the contracted power.

The power management system and power management method disclosed herein can be applied to a BEMS equipped with an EV charging function in addition to a HEMS. In the case of a BEMS, the load is installed inside or outside a building. For this reason, a house that is the target of a HEMS and a building that is the target of a BEMS are collectively referred to as a "building."

Finally, we will summarize and explain preferred embodiments of the power management system and power management method disclosed herein.

When the load operation signal detection unit detects a load operation signal, the power management system has an operation unit that calculates the difference between the upper limit of the received power and the load power, which is the total value of the power consumption of the load including the change in power consumption of the load that issued the load operation signal, and calculates the value of the charging power to be supplied to the storage battery using this difference as the maximum value.The control unit then charges the storage battery with the charging power, and causes the load that issued the load operation signal to operate in accordance with the load operation signal.

The power consumption of the load may be automatically controlled.

The power consumption of the load may be changed manually.

It is desirable for the load operation signal detection unit to have an electrical circuit that detects the load operation signal.

It is preferable that the power management system includes a memory unit that records and stores the amount of change in the power consumption of the load. In this case, it is preferable that the calculation unit learns about the amount of change in the power consumption of the load stored in the memory unit and predicts the charging power of the storage battery using the results of the learning.

The power management method manages the received power supplied from a commercial power source to a load in a building and a storage battery in a vehicle, in which a received power detection unit detects the received power from the commercial power source, a load operation signal detection unit detects a load operation signal of the load, and when the load operation signal detection unit detects a load operation signal, a calculation unit calculates the difference between the upper limit value of the received power and the load power, which is the total value of the power consumption of the load including the amount of change in power consumption of the load that issued the load operation signal, and calculates the value of the charging power to be supplied to the storage battery with this difference as the maximum value, and a control unit charges the storage battery with the charging power, and then causes the load that issued the load operation signal to operate in accordance with the load operation signal.

10: Power management system, 12: Received power detection unit, 14: Calculation unit, 16: Load operation signal detection unit, 18: Control unit, 20: House, 22, 24: Load, 30: Electric vehicle, 35: Charger, 100: Commercial power source.

Claims (7)

A power management system that manages received power supplied from a commercial power source to a load in a building and a storage battery in a vehicle,
a receiving power detection unit that detects the receiving power of the commercial power supply;
A calculation unit;
a load operation signal detection unit that detects a load operation signal of the load;
A control unit,
When the load operation signal detection unit detects the load operation signal,
the calculation unit calculates a difference between an upper limit value of the received power and a load power, which is a total value of the power consumption of the load including a change amount of the power consumption of the load that has issued the load operation signal, and calculates a value of the charging power to be supplied to the storage battery with the difference as a maximum value;
A power management system in which the control unit charges the storage battery with the charging power, and then causes the load that issued the load operation signal to operate in accordance with the load operation signal. The power management system of claim 1, wherein the power consumption of the load is automatically controlled. The power management system of claim 1, wherein the power consumption of the load is changed manually. The power management system according to claim 1, wherein the load operation signal detection unit has an electric circuit that detects the load operation signal. A memory unit that records and accumulates the amount of change in the power consumption of the load,
The power management system according to claim 1 , wherein the calculation unit learns the amount of change in the power consumption of the load stored in the memory unit, and predicts the charging power of the storage battery using a result of the learning. A power management method for managing received power supplied from a commercial power source to a load in a building and a storage battery in a vehicle, comprising:
a receiving power detection unit that detects the receiving power from the commercial power source;
a load operation signal detection unit detects a load operation signal of the load;
When the load operation signal detection unit detects the load operation signal,
a calculation unit calculates a difference between an upper limit value of the received power and a load power, which is a total value of the power consumption of the load including a change amount of the power consumption of the load that has issued the load operation signal, and calculates a value of the charging power to be supplied to the storage battery with the difference as a maximum value;
A power management method in which a control unit causes the storage battery to be charged with the charging power, and then causes the load that issued the load operation signal to operate in accordance with the load operation signal. A memory unit records and accumulates the amount of change in the power consumption of the load;
The power management method according to claim 6 , wherein the calculation unit learns the amount of change in the power consumption of the load stored in the memory unit, and predicts the charging power of the storage battery using a result of the learning.

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