Management device, management system, control method for management device, and control program

A management device includes a potential usable power calculator that computes a measurement value or an estimated value for a potential usable power which is the amount of power available when the power consumption of an electrical appliance and a potential feed-in amount that can be sold are excluded from the power output from the solar power device; a planned usage determination unit that identifies a planned usage time that a user plans to use a designated appliance; an effective time determination unit that identifies a continuous effective time when a physical quantity representing a state that changes due to the designated appliance using the potential usable power is within a range that is effective for a user; and a scheduler that creates an operation schedule indicating at least an operation start time for the designated appliance on the basis of the planned usage time and the continuous effective time.

FIELD

The present invention relates to a management device for managing a power generator and an electrical appliance, a management system, a control method for a management device, a control program.

BACKGROUND

A growing number of factories and residences are installing solar power devices. Electrical appliances in the factory or the home may consume the energy generated by a solar power device with the remaining surplus energy sold back to the power company. This kind of solar power device requires a power control device that controls the supply of the energy generated by the solar power device.

While the power control device may supply the surplus energy to the power company's power grid, the surplus energy cannot be supplied to the grid, i.e., sold back to the power company when the voltage setting of the grid exceeds a certain value (set point) the surplus energy cannot be supplied to the grid. In this case, some or all the surplus energy is not used, but cannot be sold back to the grid, i.e., this creates potential usable energy.

Consequently, techniques for making this potential usable energy available have been disclosed. For instance, Patent Document 1 describes a power control device that terminates supply of surplus energy to the grid when the voltage setting of the grid exceeds a threshold, and modifying the operation of an electrical appliance so that the appliance consumes more power. Patent Document 2 also describes a power control device; the device controls supply to the grid and the charging and discharging of a battery to thereby ensure that the voltage setting of the grid remains at or below a predetermined threshold.

RELATED ART DOCUMENTS

Patent Documents

SUMMARY

Despite that in some instances the existing technologies described above fail to effectively take advantage of the potential usable energy.

More specifically, even if the potential usable energy were available for operating an electrical appliance, there may be no benefit of this availability to the user if the user does not operate the appliance immediately. In this case, the potential usable energy is merely being consumed, and so this cannot be considered effective use of the potential usable energy.

Embodiments of the present invention address the foregoing challenges by providing a management device, a control method for the management device, and the control program that effectively uses potential usable energy.

To address the aforementioned challenges a management device according to embodiments of the invention is configured to manage a power generator and an electrical appliance, the management device including: a potential usable power calculator configured to compute a measurement value or an estimated value for a potential usable power which is the amount of power available when the power consumption of the electrical appliance and a potential feed-in amount that can be sold are excluded from the power output from the power generator; a planned usage determination unit configured to identify a planned usage time that a user of a designated appliance plans to use the designated appliance; an effective time determination unit configured to identify a continuous effective time when a physical quantity representing a state that changes due to the designated appliance using the potential usable power is within a range that is effective for a user of said designated appliance; and a scheduler configured to create an operation schedule indicating at least an operation start time for the designated appliance on the basis of the planned usage time and the continuous effective time.

According to this configuration creates an operation schedule for the designated appliance on the basis of the planned usage time and the continuous effective time. The potential usable energy can thus be used to operate the designated appliance most likely to provide a benefit for use thereof. Embodiments of the present invention are therefore able to effectively use potential usable energy. The aforementioned configuration also allows effective use of potential usable energy without introducing special devices such as storage batteries or the like (i.e., with less startup investment costs).

The scheduler in a management device according to the embodiments may also determine an operation schedule for the planned usage time on the basis of additional power consumption required to ensure that the physical quantity representing the state that changes due to the designated appliance is within a range that is effective for the user.

The aforementioned configuration makes use of the potential usable energy while accounting for the overall costs.

The operation schedule in a management device according to the embodiments may further indicate an operation period for the designated appliance.

The scheduler in a management device according to the embodiments may determine an operation schedule for a plurality of designated appliances where at least any of the power consumption and the period required for operation is different.

The scheduler in a management device according to the embodiments may determine an operation schedule that maximizes the usage rate for the potential usable power.

The aforementioned configuration maximizes the use efficiency for the potential usable power.

The scheduler in a management device according to the embodiments may determine the operation schedule on the basis of a physical quantity indicating the state of the designated appliance.

In the aforementioned configuration the scheduler may, for instance, specify the power required by the designated appliance on the basis of the physical quantity representing the state of said designated appliance. The scheduler may therefore determine an operation schedule responsive to the state of the designated appliance.

In a management device according the embodiments the potential usable power calculator may compute an estimated value for the potential usable power during a predetermined period by subtracting an estimated value for the power consumption during the predetermined period and an estimated value for the potential feed-in amount during the predetermined period from an estimated value for the power output during the predetermined period.

With the aforementioned configuration, the potential usable power may be estimated by estimating the power output, the power consumption, and the potential feed-in amount.

In a management device according to the embodiments the potential usable power calculator may computes a measurement value for the potential usable power by subtracting a measurement value for the power consumption and a measurement value for the potential feed-in amount from a measurement value for the power output.

With the aforementioned configuration, a measurement value may be computed for the potential usable power by measuring the power output, the power consumption, and the potential feed-in amount.

The management device according to the embodiments may further include a data acquisition unit configured to acquire power data from a meter, the power data representing a measurement value for at least any of the power output, the power consumption, and a feed-in amount; and the potential usable power calculator may update the estimated value for the potential usable power during the predetermined period on the basis of the power data.

According to the aforementioned configuration the potential usable power calculator may update an estimated value for the potential usable power on the basis of at least any of the measurement values for the power output, the power consumption, and the feed-in amount measured by the meter. It is therefore possible to improve the accuracy of estimating the potential usable power. Moreover, it is also possible more efficiently take advantage of the potential usable energy.

In a management device according to the embodiments the data acquisition unit acquires power data from a meter representing measurement values for the power output, the power consumption, and a feed-in amount; the potential usable power calculator computes a measurement value for the potential usable power by subtracting a measurement value for the power consumption and a measurement value for the potential feed-in amount from a measurement value for the power output; and the management device may further include: an assessment unit configured to determine whether or not the difference between the estimated value and the measurement value for the potential usable power is greater than or equal to a predetermined value; and the potential usable power calculator is configured to update the estimated value for the potential usable power when the difference is greater than or equal to a predetermined value.

The aforementioned configuration updates the estimated value for the potential usable power when there is an offset between the estimated value and the measurement value for the potential usable power. This prevents unnecessary updates to the potential usable power.

A management device according to the embodiments may further include an appliance controller configured to operate the designated appliance on the basis of the operation schedule.

The aforementioned configuration saves on electricity costs because the designated appliance is operated using the potential usable energy. The appliance controller also operates the designated appliance automatically, eliminating the inconvenience to the consumer.

A management device according to the embodiments may at least one of the power generator and the electrical appliance owned by a plurality of consumers.

The scheduler in a management device according to the embodiments may determine which of the designated appliances in the plurality of electrical appliances owned by the plurality of consumers is to receive potential usable energy.

The scheduler in a management device according to the embodiments may determine an operation schedule for the designated appliances taking into account a distribution loss that occurs when power is distributed via a distribution network interconnecting the plurality of consumers.

A management system according to the embodiments includes a management device as above described, said a power generator and said electrical appliance.

To address the aforementioned challenges a control method for a management device configured to manage a power generator and an electrical appliance, the control method with steps including computing a measurement value or an estimated value for a potential usable power which is the amount of power available when the power consumption of the electrical appliance and a potential feed-in amount that can be sold are excluded from the power output from the power generator; identifying a planned usage time that a user of a designated appliance plans to use the designated appliance; identifying a continuous effective time when a physical quantity representing a state that changes due to the designated appliance using the potential usable power is within a range that is effective for a user of said designated appliance; and creating an operation schedule indicating at least an operation start time for the designated appliance on the basis of the planned usage time and the continuous effective time.

The aforementioned configuration provides the same effects as the aforementioned management device.

The embodiments of the management device according to the present invention may be implemented on a computer. In this case, a control program for a management device configured to cause a computer to function as a management device provided with each of the above components, and a computer readable medium whereupon said control program is stored are within the scope of the invention.

Effects

Embodiments of the present invention are able to effectively use potential usable energy.

DETAILED DESCRIPTION

An embodiment of the present invention is described below on the basis ofFIG. 1throughFIG. 6.

Management System

An overview of a management system10according to the present invention is described on the basis ofFIG. 1.FIG. 1is a block diagram illustrating an overview of a management system10according to the present invention, and an example of the main components of a management device1provided in the management system10; the management system10includes a management device1, a power control device4, and at least one meter. The term “meter” collectively refers to the power meters6a-6cand8a, as well as the power storage sensor7a, the temperature sensor7b, the temperature sensor7c, and the voltage meter8b.

The management device1controls a power generator and an electrical appliance installed on-site at consumer factories, homes, or the like. A detailed configuration of the management device1is described later.

In the example illustrated inFIG. 1, the management device1controls a solar power device3serving as the power generator, and a power storage device5a, a water heater5b, and a refrigerator5cwhich are the appliances. However, the devices controlled by the management device1are not limited thereto. Instead of a solar power device3the management device1may control any other kind of power generating device such as a wind power generator, or a fuel cell, and may also control a plurality of power generating devices. The management device1may also control one or a plurality of electrical appliances and may control any electrical appliance that consumes energy to function.

The solar power device3converts solar energy to electrical power. The solar power device3supplies the energy it generates to the power control device4.

The power control device4controls the energy generated by the solar power device3and is known as a power conditioner. The power control device4supplies an electrical appliance with the energy generated by the solar power device3to allow self consumption, and supplies the energy generated by the solar power device3to the power grid (reverse power flow) to sell power back to the power company. In addition, the power control device4sends the management device1data representing the amount of power generated by the solar power device3(power output); the amount of power supplied to the electrical appliance, and the amount of power supplied to the power grid (feed-in amount).

Although the management device1and the power control device4are separate in the example inFIG. 1, the management device1and the power control device4may be combined.

The power grid2is a system owned by the power company, and supplies an electrical appliance installed on-site at the consumer with energy. The power grid2is provided with a power meter8athat measures the total amount of power supplied from the power grid2to the appliances (purchased amount) and a voltage meter8bthat measures the voltage of the power grid2.

The power meter8asends to the management device1power data representing the purchased amount measured thereby. The voltage meter8bsends to the management device1voltage data indicating the voltage setting the power grid2measured thereby.

The power storage device5aconverts the power supplied from the power grid2and the power control device4into chemical energy and stores the energy therein. The power storage device5aalso discharges the energy stored therein to other electrical appliances as needed. The water heater5buses the energy supplied from the power grid2and the power control device4to heat water. The refrigerator5euses the energy supplied from the power grid2and the power control device4to keep inside the refrigerator5cat a predetermined temperature.

Each appliance is provided with power meter for measuring the amount of power that the appliance used (power consumed), and a physical quantity sensor for measuring a physical quantity indicating the state of the appliance. More specifically, the power storage device5ais provided with a power meter6athat measures the amount of power consumed in order to store power (energy conversion), and a power storage sensor7athat measures the amount of energy stored in the power storage device5a(power stored). The water heater5bis provided with a power meter6bthat measures the amount of power consumed by the water heater5b, and a temperature sensor7bthat measures the temperature of the water heated by the water heater5b.The refrigerator5cis provided with a power meter6cfor measuring the amount of power consumed by the refrigerator5c, and a temperature sensor7cfor measuring the temperature inside the refrigerator5c.

Each of the power meters6a-6csends the management device1power data representing the power consumption measured thereby. The power storage sensor7a, the temperature sensor7b, and the temperature sensor7ceach sends the management device1physical quantity data indicating the amount of power stored and the temperature respectively measured thereby.

Potential Usable Energy

As above described, a consumer may sell energy generated to the power grid2. However, a set point is established as a threshold for the voltage of the power grid2; energy cannot flow back into the power grid2when the voltage of the power grid2equals or exceeds the set point. That is, there is an upper limit value to the amount of power that may be sold (potential feed-in amount). Consequently, this may lead to potential usable energy, which cannot be consumed or sold when the power output equals or is greater than the total of the self-consumed power (below, the total power consumption for normal appliances) and the potential feed-in amount. Note that surplus energy refers to the energy output minus self-consumed energy, and unused energy refers to surplus energy minus potential usable energy.

Embodiments of the present invention address effective use of potential usable energy. More specifically, embodiments of the present invention compute the potential usable energy and determine an operation schedule for a designated appliance on the basis of a planned usage time and a continuous effective time for the designated appliance. Embodiments of the present invention are thus able to effectively use potential usable energy. Embodiments of the present invention also allow effective use of potential usable energy without introducing special devices such as storage batteries or the like (i.e., with less startup investment costs).

Here a designated appliance is an electrical appliance that operates by consuming the potential usable energy. Additionally, an electrical appliance a consumer operates as normal with no potential usable energy available is referred to as a normal appliance. A designated appliance may be different from a normal appliance or may the same as a normal appliance.

Note that while the aforementioned set point is a constant value, the voltage setting of the power grid2may fluctuate in accordance with, for instance, the purchased amount and feed-in amount from each of the consumers supplied energy by the power grid2. That is, the potential feed-in amount is the amount of power corresponding to the voltage setting (i.e., the set point); however, the potential feed-in amount fluctuates in accordance with the purchased amount and the feed-in amount of each consumer.

Management Device Configuration

As illustrated inFIG. 1, the management device1is provided with a controller11, a storage unit12, and a communication unit13. The management device1may also be provided with a display unit, an input unit, a voice input unit, a voice output unit or the like; however, these components are not illustrated as the same are unrelated to the features of the invention.

The communication unit13allows communication with other devices such as the power control device4, the meters, and the like via wired or wireless communication, and exchanges data in accordance with commands from the controller11. For instance, the communication unit13acquires power data, voltage data, and physical quantity data from the power control device4and the meters in accordance with commands from the controller11.

The input unit14allows a user to enter command signals for the management device1to thereby operate the management device1. The input unit14may be made up of input devices such as a keyboard, a mouse, a keypad, an input button, or the like. The input unit14may also be a remote control device such as a remote controller that is separate from the management device1.

The controller11temporarily reads a program from the storage unit12into a temporary storage unit (not shown) and runs the program to thereby execute various computations, and provide overall control of all the components in the management device1.

In the embodiment the controller11includes a data acquisition unit21, an estimation unit22, a potential usable power calculator23, a scheduler24and an appliance controller25which are provided as function blocks therein. The function blocks in the controller11may be realized by a central processing unit (CPU) reading a program stored on a storage device implemented with a read-only memory (ROM) into a temporary storage unit implemented with a random-access memory (RAM), and running the program.

The data acquisition unit21acquires power data, voltage data, and physical quantity data from the power control device4and the meters through the communication unit13. The data acquisition unit21outputs the power data, voltage data, and physical quantity data obtained thereby to the estimation unit22and the potential usable power calculator23. The data acquisition unit21also stores the power data, voltage data, and physical quantity data obtained in the storage unit12.

The data acquisition unit21may also acquire planned usage time data from an external device such as a user terminal). This planned usage time data indicates the time a user plans to use an electrical appliance (designated appliance). The data acquisition unit21outputs the planned usage time data obtained thereby to the scheduler24.

The estimation unit22estimates the power output generated by the solar power device3, the total power consumption of the normal appliances, and the power that may be sold (potential feed-in amount) within a predetermined period. The estimation unit22outputs the estimated values for the power output, the total power consumption, and potential feed-in amount to the potential usable power calculator23.

Here the predetermined period may be any period such as 30 minutes, one hour, one day, or the like; or a period counted from the latest time.

The estimation unit22estimates the power output generated by the solar power device3within the predetermined period on the basis of, for instance, weather information indicating the temperature, humidity, atmospheric pressure, solar irradiance, and the like during that predetermined period. The estimation unit22may also estimate the power output generated by the solar power device3within a predetermined period on the basis of past or most recent power output or weather information. The estimation unit22may also estimate the power output generated by the solar power device3during a predetermined period on the basis of panel temperature in the solar power device3, a physical quantity indicating the state of the solar power device3, or a rated value for the solar power device3. Finally, the estimation unit22may estimate the power output through a combination of the aforementioned criteria. In this case, for instance, the data acquisition unit21may acquire weather information from an external device (not shown) connected to the Internet via the communication unit13, acquire physical quantity data from a physical quantity sensor (not shown) installed at the solar power device3, and store the weather information and the physical quantity data in the storage unit12.

The estimation unit22may also estimate a total power consumption for the normal appliances during a predetermined period on the basis of, for instance, past or most recent power consumption by the normal appliances. Here, the total power consumption estimated by the estimation unit22does not include the power consumption of a designated appliance. That is, the estimation unit22estimates the total power consumption as the total power consumption of the electrical appliances regularly operated by the consumer with no potential usable energy available. Therefore, the past or most recent power consumption data referenced by the estimation unit22is the power consumption data for normal appliances and does not include the power consumption of a designated appliance.

The estimation unit22may also estimate a potential feed-in amount during a predetermined period on the basis of, for instance, estimated values for the power output and the total power consumption during the predetermined period, as well as a set point.

The estimation unit22may also estimate when a user's planned usage time for an electrical appliance (designated appliance) on the basis of, for instance, the past or most recent power consumption of the normal appliances. The estimation unit22outputs the planned usage time data obtained thereby to the scheduler24.

The management device1is not limited to being provided with the estimation unit22in the embodiment. For instance, the power control device4or another device on the Internet may estimate the power output, the total power consumption, the potential feed-in amount, and the like. In this case, the data acquisition unit21may acquire an estimated value for the power output, the total power consumption, the potential feed-in amount, and the like from the power control device4or the other device on the Internet via the communication unit13. Additionally, when there is plurality of management devices1, a first management device1may estimate values for the power output, the total power consumption, the potential feed-in amount, or the like, and a second management device1may obtain the estimated values from said first management device1.

The potential usable power calculator23computes a measurement value or an estimated value for the potential usable power; here the potential usable power is the amount of power remaining after excluding the total power consumption of the normal appliances and the potential feed-in amount from the power output generated by the solar power device3. The potential usable power calculator23outputs the measurement value or estimated value for the potential usable power computed thereby to the scheduler24.

More specifically the potential usable power calculator23computes an estimated value for the potential usable power during a predetermined period by subtracting the estimated values for the total power consumption and the potential feed-in amount during the predetermined period from the estimated value for the power output during the predetermined period. The potential usable power calculator23also calculates a measurement value for the potential usable power during a predetermined period by subtracting the measurement values for the total power consumption and the potential feed-in amount during the period from the measurement value for the power output during the predetermined period.

The potential usable power calculator23may also compute a potential usable power period, i.e., a period when potential usable energy becomes available. The potential usable power calculator23may also specify a time-to-set-point which is the time the power output reaches power corresponding to the set point.

The potential usable power calculator23may update an estimated value previously computed for the potential usable power during a predetermined period, on the basis of at least any of the measurement values for power output, the total power consumption, and the feed-in amount.

As illustrated inFIG. 1, the potential usable power calculator23is provided with an assessment unit26. The assessment unit26determines whether or not the difference between a current estimated value for the potential usable power computed by the potential usable power calculator23and a current measurement value for the potential usable power is greater than or equal to a predetermined value. The potential usable power calculator23updates subsequent estimated values for the potential usable power when the assessment unit26determines that the difference is greater than or equal to a predetermined value.

The management device1is not limited to being provided with a potential usable power calculator23in the embodiment. For example, the power control device4or another device on the Internet may compute the potential usable power. In this case, the data acquisition unit21may obtain the potential usable power from the power control device4or another device on the Internet via the communication unit13. In addition, when there is a plurality of management devices1, a first management device may calculate the potential usable power, and a second management device1may obtain the potential usable power computed from said first management device1.

The scheduler24may determine an operation schedule that indicates at least the operation start time of a designated appliance so that one or a plurality of designated appliances may be operated using the potential usable power. The scheduler24outputs the operation schedule determined thereby to an appliance controller25.

The scheduler24may determine an operation schedule that indicates at least any of an operation end time for the designated appliance, and operation period, and an output rate for the designated appliance in addition to the operation start time. For instance, if the designated appliance were a water heater, then the output rate would be the temperature of the water heated by the water heater; if the designated appliance were an air conditioner, then the output rate would be the temperature setting for the air conditioner.

As illustrated inFIG. 1, the scheduler24is provided with a planned usage determination unit27, and an effective time determination unit28. The planned usage determination unit27identifies a planned usage time a user plans to use a designated appliance; the effective time determination unit28identifies a continuous effective time when a physical quantity indicating a state that change due to the designated appliance using the potential usable power is within a range that is effective for the user of said designated appliance. In this case, the scheduler24may determine an operation schedule on the basis of a planned usage time and a continuous effective time for the designated appliance. Moreover, the scheduler24may determine an operation schedule for the user's planned usage time on the basis of additional power consumption required to ensure that a physical quantity representing the state that changes due to the designated appliance is within a range that is effective for the user.

The planned usage determination unit27may specify the planned usage time data that represents the planned usage time data obtained by the data acquisition unit21as the planned usage time a user plans to use the designated appliance. The planned usage determination unit27may specify the planned usage time estimated by the estimation unit22as the period a user plans to use the designated appliance. The planned usage determination unit27may specify the planned usage time the user enters via the input unit14as the time the user plans to use the designated appliance. Note that the planned usage time specified by the planned usage determination unit27may be a certain time (e.g., 6:00 pm.), or may be range of times (e.g., 6:00 pm to 7:00 pm).

The scheduler24may determine an operation schedule for a plurality of designated appliances where at least any of the power consumption and the period required for operation is different. The scheduler24may also determine an operation schedule that provides the maximum usage rate for the potential usable power.

The scheduler24may determine the operation schedule on the basis of a physical quantity indicating the state of the designated appliance. More specifically, the scheduler24may determine at least any of the power and the period required to operate the designated appliance on the basis of a physical quantity indicating the state of the designated appliance, and determine an operation schedule for said designated appliance.

The management device1is not limited to being provided with the scheduler24in the embodiment. For example, the power control device4or another device on the Internet may determine the operation schedule. In this case, the data acquisition unit21may obtain the operation schedule from the power control device4or another device on the Internet via the communication unit13. In addition, when there is a plurality of management devices1, a first management device may determine an operation schedule, and a second management device1may obtain the operation schedule determined from said first management device1.

The appliance controller25may operates the designated appliance on the basis of the operation schedule. More specifically, the appliance controller25transmits a control signal via the communication unit13to the designated appliance; the control signal controls the operation start, the operation termination, and the output rate of the designated appliance.

The storage unit12stores programs or data referenced by the controller11; for example, the storage unit12may store power data31, voltage data32, physical quantity data33, and the like. Thus, past power output, power consumption, purchased amount, feed-in amount, and the voltage setting of the power grid2, as well as physical quantities related to the appliances and the like may be stored in the storage unit12as power data31, voltage data32, and physical quantity data33. Therefore, the estimation unit22, potential usable power calculator23, and the scheduler24may reference this data.

Processes in the Management Device

Determining the Operation Schedule

The process of determining an operation schedule carried out by the management device1is described on the basis ofFIG. 2.FIG. 2is a flowchart illustrating an example of an operation schedule determination process run by the management device1; In this example, the potential usable energy available during a predetermined period (e.g., one day) is estimated and an operation schedule determined in advance for the potential usable power period.

As illustrated inFIG. 2, the estimation unit22estimates the power output, the total power consumption, and the potential feed-in amount (Si). The potential usable power calculator23estimates the potential usable power on the basis of the estimated values for power output, the total power consumption, and the potential feed-in amount determined by the estimation unit22(S2: potential usable power computation step).

If at this point potential usable energy is available (YES at S3), the data acquisition unit21obtains physical quantity data from a physical quantity sensor that measures a physical quantity indicating the state of a designated appliance (S4). The scheduler24references the physical quantity data obtained by the data acquisition unit21, takes into account the status of the designated appliance, and determines an operation schedule (S5: schedule determination step).

Note that if no potential usable energy is available (NO at S3), the management device1does not create an operation schedule and ends the operation schedule determination process.

Updating the Operation Schedule

The process of updating an operation schedule carried out by the management device1is described on the basis ofFIG. 3.FIG. 3is a flowchart illustrating an example of an operation schedule updating process run by the management device1; in this example the management device updates the operation schedule in real time while the designated appliance is operating.

As illustrated inFIG. 3, the appliance controller25operates the designated appliance on the basis of an operation schedule created in advance by the scheduler24(S11). At this point, the data acquisition unit21acquires voltage data indicating the most recent voltage setting on the power grid, as well as power data representing the latest power output, power consumption, and feed-in amount (S12). The potential usable power calculator23calculates a new measurement value for the most recent potential usable power on the basis of data representing the most recent measurement value obtained by the data acquisition unit21. The assessment unit26calculates the difference between the estimated value for the potential usable power calculated for this period in advance, and the new measurement value for the potential usable power (S13).

The flow returns to S12if the difference calculated by the assessment unit26is below a predetermined value (NO at S14).

In contrast, if the difference calculated by the assessment unit26is greater than or equal to the predetermined value (YES at S14), i.e., if there is an offset between the estimated value and the measurement value, the estimation unit22takes into account the most recent measurement values for the power output, total power consumption, and potential feed-in amount, to estimate a power output, a total power consumption, and a potential feed-in amount (S15). The potential usable power calculator23estimates the potential usable power on the basis of the estimated values for the power output, the total power consumption, and the potential feed-in amount determined by the estimation unit22(S16).

Subsequently, the data acquisition unit21obtains physical quantity data from a physical quantity sensor that measures a physical quantity indicating the state of a designated appliance (S17). The scheduler24determines a new operation schedule on the basis of the potential usable power estimated by the potential usable power calculator23in S16and the physical quantity data obtained by the data acquisition unit21, and updates a previously created operation schedule (S18).

The appliance controller25operates the designated appliance on the basis of the operation schedule updated by the scheduler24(S11).

Types of Designated Electrical Appliances

The types of designated appliances are described on the basis ofFIG. 4.FIG. 4(a)throughFIG. 4(c)illustrate examples of a power consumption requirement and a time requirement for a designated appliance. The Y-axis and the X-axis in the graphs represent the power consumption and the time respectively inFIG. 4(a)throughFIG. 4(c).

There are various types of designated appliances, and each of these types require various amounts of power consumption (power requirement) and time (time requirement) to operate. The designated appliance illustrated inFIG. 4Arequires a lot of energy for a short time. A designated appliance may be a water heater, a microwave oven, a fast charger, or the like. The designated appliance illustrated inFIG. 4Brequires a moderate amount of energy for a fixed time. For example, these may be storage batteries, washing machines, or the like. The designated appliance illustrated inFIG. 4Crequires relatively little energy over a long period. For example, lighting appliances, televisions, music players or the like.

Thus, designated appliances have various power requirements and time requirements. The scheduler24may therefore determine an operation schedule that takes these requirements into account to provide a maximum use rate for the potential usable energy. Specific examples thereof are described below.

FIRST EXAMPLE

An operation schedule created by a management device1according to embodiments of the invention is described on the basis ofFIG. 5. The first example describes a case where the power selling price is greater than the power purchase price per unit power. The first example also illustrates an operation schedule created upon estimating the potential usable power for a one-day period.FIG. 5is also an example of a destination for the energy output when the power selling price is greater than the power purchase price.

As illustrated inFIG. 5all the energy generated between the time t1to time t2and time t5to time t6is sold to maximize the power selling price since the power output does not exceed the power corresponding to the set point. Additionally, the energy consumed by normal appliances between the time t1to time t2and time t5to time t6can be covered by the power purchased from the power grid2.

However, all the energy generated between the time t2to time t5cannot be sold because the power output equals or exceeds the power corresponding to the set point. Therefore, the energy that remains after removing the potential feed-in amount from the power output is used to operate normal appliances through self consumption.

Although the maximum amount of energy is sold and normal appliances use the energy generated through self consumption some energy remains between the time t3to time t4. That is, between time t3to time t4is a potential usable power period where potential usable energy is available.

Therefore, the scheduler24creates an operation schedule that provides the maximum usage rate for the potential usable energy (FIG. 5). More specifically, the scheduler24determines the operation start time and operation end time for the three types of designated appliances (FIG. 4) so that graphs do not fall outside the power output curve.

SECOND WORKING EXAMPLE

An operation schedule created by a management device1according to embodiments of the invention is described on the basis ofFIG. 6. The second example describes a case in which the power purchase price is greater than the power selling price per unit power. The second example also illustrates an operation schedule created upon estimating the potential usable power for a one-day period.FIG. 6illustrates an example of energy output when the power purchase price is greater than the power selling price.

As illustrated inFIG. 5the energy generated between the time t11to time t12and time t15to time t16is used to operate normal appliances and thus self consumed to minimize the power purchase price since the power output does not exceed the power corresponding to the set point. If the power output is less than the total power consumption of the normal instrument, then the gap energy is bought from the power grid2. In contrast, if the power output is greater than the total power consumption of the normal instruments, then the excess energy is sold.

The energy generated between the time t12to time t13and between the time t14to time t15is used to operate normal appliances because the power output does not exceed the power corresponding to the apparent set point when taking self consumption into account. The excess energy is sold.

Although the maximum amount of excess energy is sold and normal appliances use the energy generated through self consumption some energy remains between the time t13to time t14. That is, between the time t13to time t14is a potential usable power period where potential usable energy is available.

Therefore, the scheduler24creates an operation schedule that provides the maximum usage rate for the potential usable energy (FIG. 6). More specifically, the scheduler24determines the operation start time and operation end time for the three types of designated appliances (FIG. 4) so that graphs do not fall outside the power output curve.

As illustrated in the first and second examples, the management device1is capable of effectively making use of potential usable energy. It is thus possible to provide a consumer with cost savings on electricity. The management device1also operates a designated appliance automatically, eliminating the inconvenience to the consumer. Additionally, the system maintains the stability of the power grid2because power is not fed-in at greater than the set point.

The Continuous Effective Time

The designated appliances that use the potential usable energy to operate are not the electrical appliances originally slated for operation during the potential usable power period (i.e., these designated appliances are not electrical appliances that a user uses during the potential usable power period). Therefore, a designated appliance is preferably able to extend the benefit of using the potential usable energy. This kind of designated appliance may be a water heater5b, a power storage device5a, an air conditioner or the like.

A specific description of the continuous effective time is given on the basis ofFIG. 7with a water heater5bas an example.FIG. 7depicts a relationship between the temperature of water generated by a water heater5band the time elapsed. The vertical axis of the graph inFIG. 7is the water temperature, and the horizontal axis is the time elapsed. Here the temperature the user sets for the water heater5bis assumed as a temperature setting Tu.

The water heater5buses the potential usable energy during a period from the time t21to time t23to generate water of a predetermined temperature. However, as illustrated inFIG. 7the temperature of the water in the water heater5bdecreases over time due to natural thermal radiation. The temperature of the water in the water heater5bdecreases to the user's temperature setting Tu at the time t24. It is sometime after the time t23when the user can no longer use water at the temperature setting Tu because the water temperature falls below the temperature setting Tu.

Therefore, the user may use water at the temperature setting Tu up until the time t24without needing to operate the water heater5bagain. In other words, the period wherein the user can effectively use the water heater5b, i.e., continuous effective time, is from a time t22when the water heater5buses the potential usable energy to generate water at a temperature exceeding the temperature setting Tu until the time t24when the water temperature falls below the temperature setting Tu; this is the period during which the temperature of the water in the water heater5bis no less than the temperature setting Tu. Therefore, as long as it is during the continuous effective time the user can use water at the temperature setting Tu without needing to operate the water heater5bagain.

As above mentioned the state of the designated appliance that changes when the designated appliance uses the potential usable power can be expressed as a physical quantity. In the case of the water heater5b, this physical quantity is the temperature of the water in the water heater5band the effective range for the user using the designated appliance is the range where the water temperature is greater than or equal to the temperature setting Tu.

However, the user must activate the water heater5bagain if the user wishes to use the water heater5bbeyond the time t24. For instance, when the user wishes to use heated water at a time t26, the user must activate the water heater5bat a time t25prior to the user usage time t26to increase the water temperature. That is, additional energy must be consumed to operate the water heater5bin order for the temperature of water in the water heater5bto be greater than or equal to the temperature setting Tu at the user usage time t26. This added power consumption is required to ensure that the physical quantity representing the state that changes due to the designated appliance is within a range that is effective for the user when the user plans to use the designated appliance.

While this description is given with a water heater5bas an example, the situation is identical for a power storage device5a, an air conditioner, or the like. Again, the state of the designated appliance that changes when the designated appliance uses the potential usable power can be expressed as a physical quantity. In the case of power storage device5a, the physical quantity is the energy stored in the power storage device5aand the effective range for the user using the designated appliance is a range that is greater than or equal to the amount of power to be stored which is set by the user. In the case of an air conditioner, the physical quantity is the temperature of a prescribed space regulated by the air conditioner and the effective range for the user using the designated appliance is temperature range which is set by the user.

Techniques for Identifying the Continuous Effective Time

Next, the specific techniques employed by the effective time determination unit28to determine the continuous effective time are described. This description also uses the water heater5bas an example.

First, a basic equation 1 for heat transfer (i.e., natural thermal radiation) is provided below. In Equation 1, E is the amount of heat transfer per unit time (J/s); k is the thermal conduction rate (1/JsKm); A is the surface area (m2) of the water heater5b;d is the thickness (m) of the heat insulating material in the water heater5b;T(t) is the temperature (° C.) of water in the water heater5bat time t; and Ta(t) is the ambient temperature (° C.) at time t. Note that Equation 1 does not take into account any effects from wind (i.e., convection of the open air).

The water heater5bdoes not change in Equation 1, therefore taking kA/d as a constant α yields the following Equation 2.
Equation 2
E=α(T(t)−Tα(t))  (2)

If unknown, α can be calculated from past data on the basis of Equation 2. The ambient temperature Ta(t) may be obtained from temperature forecast information such as a general purpose weather information site, or the like, and the forecast air temperature indicated by the forecast air temperature information taken as the ambient temperature Ta(t). Here, the amount of heat transfer E per unit time may be obtained from Equation 2 when the temperature T(t) of the water in the water heater5bat a certain time t is known.

The amount of heat transfer E computed may be used to compute the water temperature T(t+1) in the water heater5bat time t+1 based on the following Equation 3. In Equation 3, Q is the heating value (J), M is the capacity (kg) of the water heater5b, and C is the specific heat (J/kg° C.).
Equation 3
Q=MC(T(t+1)−T(t))  (3)

Thus, the temperature of the water in the water heater5bmay be estimated using Equation 2 and Equation 3. Estimating the change in temperature of the water in the water heater5bmakes it possible to specify when the temperature is the user's temperature setting Tu, and thus makes it possible to specify the continuous effective time of the water heater5b.It may not be possible to specify when, using the potential usable energy, the temperature of the water in the water heater5bwill exceed the temperature setting Tu; in this case, the continuous effective time may start at the time the water heater5bno longer operates using the potential usable energy (i.e., at the operation end time).

A more concrete example of specifying the continuous effective time is described on the basis ofFIG. 8.FIG. 8is a graph of estimated water temperature in the water heater5band the estimated ambient temperature. InFIG. 8the left vertical axis represents the estimated water temperature, and the right vertical axis represents the estimated ambient temperature; the horizontal axis is the time elapsed since an operation ended where the water heater5bused the potential usable energy (operation end time).

Here it is assumed that during normal use the water temperature in water heater5bfalls one degree Celsius (1° C.) in one hour, and the constant α is computed based on this condition. It is also assumed that the capacity of the water heater5bis 370 liters. It is further assumed that the water heater5bis operated using the potential usable energy and that the water temperature in the water heater5bis 85° C. at the operation end time for the water heater5b.Finally, it is assumed that the temperature setting of the water heater5bis 70° C.

Computing the estimated water temperature each hour from these criteria using the Equations 2 and 3 yields the graph depicted inFIG. 8. From the graph it can be determined that it takes fourteen hours from the operation end time for the water temperature to reach the temperature setting of 70° C.

Although the example given is of a water heater5b, the same technique may be used compute the change in the amount of power stored, the temperature change in a space, and the like for a power storage device5a, an air conditioner, and the like to thereby specify a continuous effective time.

While the graph of the estimated water temperature depicted inFIG. 8appears linear, the graph is actually non-linear and dependent on the ambient temperature as can be understood from the Equations 2 and 3.

THIRD EXAMPLE

As above described, the scheduler24may determine the continuous effective time for a designated appliance, and create an operation schedule on the basis of a continuous effective time. More specifically, the scheduler24may determine an operation schedule so that a designated appliance having a continuous effective time uses the potential usable energy to operate without allowing an electrical appliance that does not have a continuous effective time to operate. An electrical appliance that does not have a continuous effective time may be, for instance, an electrical appliance that is only beneficial while consuming energy, such as, a television or lighting. The scheduler24may also determine an operation schedule that gives a priority for using the potential usable energy to a designated appliance that has a longer continuous effective time.

The scheduler24may create an operation schedule that prioritizes a designated appliance that has no limit on the continuous effective time therefor over a designated appliance that has a limit on the continuous effective time therefor. The scheduler24may also create an operation schedule that prioritizes a designated appliance that has a limit on the continuous effective time therefor over a designated appliance that has no limit on the continuous effective time therefor. A designated appliance with no limit on the continuous effective time therefor provides some benefit to the user regardless of when the designated appliance is operated; for instance, an automatic vacuum cleaner, a washing machine, a dryer, a rechargeable battery in an electrical appliance (e.g., a smartphone or an electric shaver), or the like.

The scheduler24may create an operation schedule on the basis of a relationship between the continuous effective time of a designated appliance and when the user plans to use said designated appliance (planned usage time). More specifically, the scheduler24may determine an operation schedule so that a designated appliance with a continuous effective time during the user's planned usage time uses the potential usable energy to operate while not allowing an electrical appliance with a continuous effective time outside the user's planned usage time to operate. The scheduler24may also create an operation schedule that places the highest priority on operating a designated appliance with a continuous effective time within the user's planned usage time, and prioritizes operating a designated appliance with a short time between the end of the continuous effective time therefor until the user's planned usage time.

The scheduler24may also determine an operation schedule for the user's planned usage time on the basis of additional power consumption required to ensure that the physical quantity representing the state that changes due to the designated appliance is within a range that is effective for the user. More specifically, the scheduler24may create an operation schedule so that a designated appliance not requiring additional power consumption uses the potential usable power to operate (i.e., a designated appliance with an additional power consumption of zero and in other words is slated for use during the continuous effective time therefor), without allowing an electrical appliance that requires additional power consumption to operate. The scheduler24may also determine an operation schedule that gives a priority for using the potential usable energy to a designated appliance that consumes less additional power.

The scheduler24may determine an operation schedule that provides the maximum usage rate for the potential usable power in the aforementioned example. An example of a specific process for determining an operation schedule is described below. The scheduler24establishes the following priority and determines an operation schedule that operates appliances in descending order of priority and maximizes the use of the potential usable power available. The scheduler24prioritizes appliances in order of (1) appliances with a continuous effective time; (2) appliances where the user's planned usage time is during the continuous effective time of the appliance; and (3) appliances with a small amount of additional power consumption.

The process of determining an operation schedule carried out by the management device1of this example is described on the basis ofFIG. 9.FIG. 9is a flowchart illustrating an example of an operation schedule determination process run by the management device1.

As illustrated inFIG. 9, the estimation unit22estimates the power output, the total power consumption, and the potential feed-in amount (S21). The potential usable power calculator23estimates the potential usable power on the basis of the estimated values for the power output, the total power consumption, and the potential feed-in amount determined by the estimation unit22(S22: potential usable power computation step).

If potential usable energy is available (YES at S23), the planned usage determination unit27identifies a user's planned usage time for the designated appliance (S24: planned usage time determination step). The effective time determination unit28then identifies the continuous effective time for the designated appliance (S25: continuous effective time determination step). The scheduler24creates an operation schedule for the designated appliance on the basis of the planned usage time and the continuous effective time.

Note that if no instance of potential usable energy is available (NO at S23), the management device1does not create an operation schedule and ends the operation schedule determination process.

Example of Implementation in Software

The control block (and in particular the controller11) in the management device1may be implemented as logic circuits (hardware) created on an integrated circuit (IC chip) or the like, or maybe implemented in software by using a CPU.

When implemented in software, the management device1is provided with, for instance, a CPU that runs commands in a program that is software implementing each of the functions; a ROM or a storage device (referred to as recording medium) on which the aforementioned program and various data are recorded in a manner that can be read by a computer (or CPU); and RAM onto which the aforementioned program may be loaded. The objectives of the present invention can be met through the computer (or CPU) reading and executing the aforementioned program from the aforementioned recording medium. The aforementioned recording medium may be a non-transitory physical medium such as a tape, disc, card, semiconductor memory, or programmable logic circuit. The aforementioned program may also be supplied to the computer via any desired transmission medium capable of transferring the program (for example, a communication network, or broadcast waves). Finally, embodiments of the invention may also be implemented in the form of data signals encapsulated in carrier waves that are realized through the electronic transmission of the aforementioned program. The present invention is not limited to each of the above described embodiments, and may be modified in various ways and remain within the scope of the claims. The technical means disclosed in each of the different embodiments may be combined as appropriate, and an embodiment obtained in such a manner remains within the technical scope of the present invention.

Other Embodiments

Here ends the description of embodiments of the invention; the invention is not limited to the above mentioned embodiments, and may be modified in various ways insofar as the modifications do not depart from the spirit and scope of the invention.

The above described embodiments provide examples of a management device1managing the power generator (solar power device3) and the appliances (power storage device5a, water heater5b, and refrigerator5c) owned by a single consumer. However, the present invention is not limited to this configuration.

For example, as illustrated inFIG. 10, the present invention may be implemented as a management system110containing a management device101that manages power generators103a,103band/or appliances105a-105cthat are scattered among a plurality of consumers, Consumers A through C.

The management device101possesses the same configuration as the management device1in the above-mentioned embodiments; that is, the management device101includes a controller11, a storage unit12, a communication unit13, an input unit14, and the like.

Consumer A owns a power generator103a, a power control device104a, and an electrical appliance105a.Consumer B owns a power generator103b, a power control device104b, and an electrical appliance105b.Consumer C does not own a power generator and does not own a power control device, and owns only the electrical appliance105C.

In this case, the surplus energy (and potential usable energy) may be flexibly shared among the multiple Consumers A through C connected via the shared distribution network O.

When routing surplus energy (potential usable energy) among the multiple consumers, Consumers A through C, for example, the surplus energy (potential usable energy) created at one consumer, i.e., Consumer A may be supplied to the appliances105b,105cowned by multiple consumers, i.e., Consumers B, C.

Moreover, when selecting the consumer that will be supplied power by a consumer that has generated surplus energy (potential usable energy), the controller11(i.e., the scheduler24) preferably takes into account any power distribution loss that may occur when distributing power and selects where to supply power.

Hereby, for instance, it is possible to exclude consumers that are connected on a different distribution network that would create a large distribution power loss during power distribution, and select where to supply the surplus energy (potential usable energy).

Note the plurality of consumers, i.e., Consumers A through C, may own various kinds of power generators, for instance, generators that make use of natural energy such as a solar power device, wind power device, geothermal power device or the like, or may own electric generators, binary cycle power generators, or the like.

Additionally, the plurality of consumers, i.e., Consumers A through C, may own various kinds of appliances such as a power storage device, water heater, refrigerator, air conditioner (air conditioning device), electric car, illumination device, washing machine, television set, or the like.

In the above embodiments, the storage unit12, which stores various data such as the power data31, the voltage data32, and the physical quantity data33, is built into the management device1. However, the present invention is not limited to this configuration.

The various data may be stored outside the management device on a server, in the cloud, or the like for example. The same may be implemented for the system configuration illustrated inFIG. 10.

INDUSTRIAL APPLICABILITY

The present invention may be adopted in a management device that manages a power generator and an electrical appliance.

REFERENCE NUMERALS

4Power control device

7aPower storage sensor

21Data acquisition unit

23Potential usable power calculator

27Planned usage determination unit

28Effective time determination unit

103a,103bSolar power device

104a,104bPower control device