JP7829993B2 - Battery charging control system - Google Patents

Description

This invention relates to a battery charging control system.

In commercial electricity usage contracts, the basic charge is usually determined by the maximum demand value of electricity from the commercial power source (commercial electricity). The demand value refers to the average power consumed in 30-minute intervals. The highest demand value within a day is called the maximum demand value. Therefore, when using a battery charging control system that utilizes solar power, as described in Patent Document 1, if the amount of electricity used is likely to exceed the power limit set in the basic charge, the system may be used to discharge electricity from the battery to the load. This prevents the amount of electricity used from the commercial power source from exceeding the value set in the basic charge. Reducing the maximum demand value in this way is called peak cutting.

Japanese Patent Publication No. 2014-143784

To make this possible, the battery needs to be pre-charged. Furthermore, charging the battery can be done using both solar power and commercial electricity. When charging the battery with solar power, the power generation situation is affected by the weather. In other words, there may be times when the battery is not sufficiently charged. To avoid this insufficient charging, charging the battery with commercial electricity regardless of the weather is a possibility. However, in this case, even on days when there is surplus solar power, the battery will be charged with commercial electricity, increasing commercial electricity consumption.

The inventors of this invention have attempted to resolve this issue through diligent study. The problem that this invention aims to solve is to enable efficient use of storage batteries by reading weather conditions from measurement data.

To solve the above problems, a battery charging control system is provided, comprising a solar cell capable of supplying generated solar power to a battery and a load, a commercial power supply capable of supplying commercial power to a battery and a load, and a battery capable of supplying charging power to a load, all connected to a battery. The system includes a weather measurement unit capable of measuring at least one weather information (solar radiation, humidity, and atmospheric pressure) during a reference time period and transmitting the weather measurement data to a determination unit, a determination unit capable of determining whether the weather measurement data during the reference time period is above or below a threshold, and a control unit capable of controlling the method of charging the battery. The control unit, when it is expected that sufficient power generation will be performed by the solar cell based on the determination unit's results, begins controlling the battery to be charged using surplus solar power until the target time for securing the charge amount. When it is not expected that sufficient power generation will be performed by the solar cell based on the determination unit's results, it begins controlling the battery to be charged using commercial power until the target time for securing the charge amount.

Furthermore, it is preferable that the control unit be configured to begin charging the battery using both the surplus solar power and commercial power if the solar power generation exceeds the load's power consumption after charging the battery has started using commercial power.

Furthermore, it is preferable to have a configuration that allows for measurement of load power consumption during the reference time period or a time period prior to the reference time period. If the measured power consumption exceeds a threshold, the determination unit determines whether the weather measurement data for the reference time period is above or below the threshold. If the measured power consumption is below the threshold, it outputs a signal to the control unit to charge the battery using surplus solar power generation.

Furthermore, if the determination unit determines that the weather measurement data for the reference time period is below a threshold, it is preferable to configure the control unit to control the discharge amount so that the discharge rate from the battery to the load remains constant from a predetermined time after the target time for securing the charge amount until the final desired time for using the stored energy, and so that the battery charge amount reaches the set value at the final desired time for using the stored energy.

Furthermore, a battery charging control system is preferably provided, comprising a solar cell capable of supplying generated solar power to a battery and a load, a commercial power source capable of supplying commercial power to a battery and a load, and a battery capable of supplying charging power to a load, all connected to a battery. The system includes: a weather measurement unit capable of measuring at least one weather information (solar radiation, humidity, and atmospheric pressure) during a reference time period and transmitting weather measurement data to a determination unit; a determination unit capable of determining whether there will be a surplus in solar power generation using the weather measurement data for the reference time period and predicted power consumption data of the load after the reference time period; and a control unit capable of controlling the method of charging the battery. The control unit, if the determination result from the determination unit indicates that a surplus in solar power generation is expected, controls the system to begin charging the battery with the surplus solar power generation until the target time for securing the charge amount; and if the determination result from the determination unit indicates that no surplus in solar power generation is expected, controls the system to begin charging the battery with commercial power until the target time for securing the charge amount.

Furthermore, it is preferable to have a storage unit that stores past weather conditions during a reference time period, past solar power generation after the reference time period, and past load power consumption after the reference time period. The system compares the weather measurement data for the current day during the reference time period with the solar power generation after the reference time period on past days with similar weather conditions, and the load power consumption measured at the same time as the solar power generation measurement. If the solar power generation is greater than the load power consumption, the system is controlled to assume a surplus of solar power generation is expected. If the solar power generation is less than the load power consumption, the system is controlled to assume no surplus of solar power generation is expected.

This invention makes it possible to efficiently utilize a storage battery by reading weather conditions from measurement data.

This is a block diagram of a battery charging control system in an embodiment. This graph shows an example of the daily trends in power consumption, solar power generation, and battery charging/discharging, with the standard time period and target time for ensuring sufficient charge indicated. However, this is an example for a sunny day, with the solid line representing power consumption, the dashed line representing solar power generation, and the dotted line representing battery charging/discharging. This graph shows an example of the daily trends in power consumption, solar power generation, and battery charging/discharging, with the standard time period, target time for securing charge, and desired final time for using the stored energy indicated. However, this is an example of a day with poor weather, and the solid line represents power consumption, the dashed line represents solar power generation, and the dotted line represents battery charging/discharging. This is a diagram illustrating an example of a control flow.

The following describes embodiments for carrying out the invention. As can be understood from Figures 1 to 4, the battery charging control system 1 of this embodiment is connected to a battery 11 that can supply charging power to the load 12, and includes a solar cell 13 capable of supplying generated solar power (PV power) to a battery 11 and a load 12, and a commercial power supply 14 capable of supplying commercial power to the battery 11 and a load 12. Furthermore, this battery charging control system 1 includes a weather measurement unit 15 capable of measuring at least one weather information such as solar radiation, humidity, and atmospheric pressure in a reference time period t1 and transmitting the weather measurement data to a determination unit 16, a determination unit 16 capable of determining whether the weather measurement data in the reference time period t1 is above or below a threshold, and a control unit capable of controlling the method of charging the battery 11. Furthermore, the control unit is configured to start controlling the charging of the battery 11 using surplus solar power if the determination result from the determination unit 16 indicates that sufficient power generation from the solar cells 13 is expected. Conversely, if the determination result from the determination unit 16 indicates that sufficient power generation from the solar cells 13 is not expected, the control unit starts controlling the charging of the battery 11 using commercial power until the target time t2. Therefore, it becomes possible to read weather conditions from measurement data and utilize the battery 11 efficiently.

Here, we will describe an example configuration of the battery charging control system 1 of the embodiment. In the example shown in Figure 1, power can be supplied to the load 12 from the commercial power supply 14, the solar cell 13, and the battery 11. Furthermore, a line branching off from the line connecting the load 12 and the commercial power supply 14 is further branched to allow power to be supplied to the load 12 from the solar cell 13 and the battery 11.

In the battery charging control system 1 shown in Figure 1, a solar power conditioner control unit 31 (solar PCS control unit) is provided between the solar cell 13 and the load 12 to control the solar power generated by the solar cell 13. Furthermore, this battery charging control system 1 also includes a battery power conditioner control unit 33 (battery PCS control unit) between the battery 11, the load 12, and the commercial power supply 14 to control the power stored in the battery 11 and the stored power.

The battery charging control system 1 includes a weather measurement unit 15 capable of measuring weather information, and a determination unit 16 capable of making decisions based on the results measured by the weather measurement unit 15. Furthermore, the battery charging control system 1 shown in Figure 1 includes a storage unit 21 capable of storing information. It also includes a power measurement unit 23 capable of measuring power.

The result determined by the determination unit 16 can influence some of the operation of the solar power conditioner control unit 31 and the battery power conditioner control unit 33. For example, the amount of solar radiation is measured by a measuring instrument provided in the weather measurement unit 15, and it is determined whether the value of the solar radiation is above or below a threshold. If it is above the threshold, it is considered good weather, and the system is controlled to use the surplus power, which is the generated power minus the power used, to charge the battery 11. In this example, commercial power is not used at all to charge the battery 11. Note that the amount of solar radiation is higher when the weather is good and lower when the weather is bad. For example, a threshold of 200 W/ ^m² can be used, and if it is above this, the battery charging control system 1 can be controlled as if the weather is good and sufficient power generation from the solar cells is expected. If it is below this, the battery charging control system 1 can be controlled as if the weather is bad and sufficient power generation from the solar cells is not expected.

The weather measurement unit 15 does not necessarily measure solar radiation. For example, atmospheric pressure could be measured. Specifically, atmospheric pressure is measured by a measuring instrument, and it is determined whether the atmospheric pressure is above or below a threshold. If it is above the threshold, it is assumed that the weather is good and sufficient power generation by the solar panels is expected. In this example, the system can be controlled to use the surplus power (generated power minus used power) to charge the battery 11. In this example, commercial power is not used at all to charge the battery 11. Note that atmospheric pressure is higher when the weather is good and lower when the weather is bad.

Furthermore, humidity may be measured by the weather measurement unit 15. Specifically, humidity is measured by a measuring instrument, and it is determined whether the humidity is above or below a threshold. If it is below the threshold, it is assumed that the weather is good and sufficient power generation by the solar panels is expected. In this example, the system can be controlled to use the surplus power (generated power minus used power) to charge the battery 11. In this example, commercial power is not used at all to charge the battery 11. Note that humidity is lower when the weather is good and higher when the weather is bad. For example, a threshold of 65% could be used, and the battery charging control system 1 could be controlled if the humidity is below this value, assuming good weather, and controlled if it is above this value, assuming bad weather. However, since humidity can fluctuate significantly depending on the season, it is preferable to set a threshold according to the season.

Of course, it's not necessary to measure only one thing; multiple types of data can be measured, and the combination of these can be used to estimate the quality of the weather. For example, if multiple items such as solar radiation, humidity, and atmospheric pressure are used as criteria, it could be estimated that the weather is good and sufficient power generation from the solar panels can be expected if all items are on the side that would be judged as good weather based on the threshold. In this case, even if only one item is not on the side that would be judged as good weather, it would be judged that sufficient power generation from the solar panels cannot be expected, but the judgment does not have to be in this way.

Weather measurement data serves as a basis for determining electricity usage on any given day, so data covering a certain period is preferable to instantaneous data. Therefore, it is best to take multiple measurements within a given time period.

The reference time period t1 should be any time period during which the battery 11 can be charged using commercial power before power consumption reaches its peak. However, it is preferable to set the reference time period t1 to "around the time when power generation by the solar panels 13 begins if the weather is good" or "during the time when morning power consumption begins to rise." In the example shown in Figure 2, the reference time period t1 is set to the 30 minutes from 8:30 AM to 9:00 AM.

In the example shown in Figure 2, under good weather conditions, solar power generation gradually increases until early afternoon, then gradually decreases from around 3 PM, and by around 6 PM, no power is being generated. Looking at the balance with power consumption, power consumption exceeds solar power generation from around 8 AM to 10:30 AM. Furthermore, from around 10:30 AM to 5 PM, solar power generation exceeds power consumption. In other words, there is a surplus of power from around 10:30 AM to 5 PM.

Furthermore, in this example, charging of the battery 11 begins around 10:30 AM. This is because, based on the determination result from the determination unit 16, if sufficient power generation from the solar cell 13 is expected, the system controls the charging of the battery 11 until the target time t2 to be carried out using the surplus solar power generation (PV power - power consumption).

In the example shown in Figure 2, the periods of relatively high power consumption coincide with periods when sufficient solar power is available, meaning that peak power consumption is not a concern on those days. Therefore, the power stored in the battery 11 is used by the load 12 to bridge the gap between solar power and power consumption once power consumption exceeds solar power. In this example, since the battery 11 is sufficiently charged, most of the power used after 10:30 AM is supplied from sources other than the commercial power supply 14.

Of course, not every day is sunny. In the example shown in Figure 3, the weather is poor, and the solar panels 13 are not generating much power. Even so, peak power consumption can exceed 40 kW, so peak shaving is desired. Therefore, on days when power consumption is not high, it is desirable to send power from the commercial power source 14 to the battery 11 and store it. Here, after checking the weather conditions at the reference time t1, power is sent from the commercial power source 14 to the battery 11 from around 9:00 AM, and the battery 11 is then charged. However, power is only sent from the commercial power source 14 to the battery 11 until the target time t2 for ensuring sufficient charge; after that, the power stored in the battery 11 is gradually released so that it can be used by the load 12. The target time t2 for ensuring sufficient charge should be set to a time before the peak time. In the example shown in Figure 3, the target time t2 for ensuring sufficient charge is set to the time immediately before the peak time.

In this case, it is preferable to control the amount of power released from the battery 11 (the amount supplied to the load 12) to remain approximately constant from a predetermined time until the desired final time of battery use t3. This is because it allows for stable suppression of the amount of commercial power 14 used. In the example shown in Figure 3, the control is set to remain approximately constant from the target time of charge acquisition t2 until the desired final time of battery use t3. It is preferable to set the desired final time of battery use t3 to the time when the peak of power consumption by the load 12 is expected to end.

Furthermore, to enable this, it is preferable that, when the determination unit 16 determines that the weather measurement data for the reference time period t1 is below a threshold, the discharge amount from the battery 11 to the load 12 remains constant from a predetermined time after the target time for securing the charge amount t2 until the desired final time for using the stored energy t3, and that the control unit controls the discharge amount so that the charge amount of the battery 11 reaches a set value at the desired final time for using the stored energy t3.

In this embodiment, some power remains in the battery 11 at the desired final power usage time t3, enabling a response to sudden power shortages. The setting value for the remaining capacity in the battery 11 can be determined according to the desired capacity. Setting this value to 0 will use up all the power available in the battery 11; however, considering emergency response, a setting value greater than 0 is preferable.

Incidentally, even if the weather forecast based on weather information measured during the reference time period t1 predicts unfavorable weather, it is possible that the weather may improve slightly after a few hours. Therefore, if the solar power generation exceeds the power consumption of the load 12 after charging the battery 11 has begun using commercial power, it is preferable for the control unit to start charging the battery 11 using both the surplus solar power and commercial power. This allows for achieving the target charge level while suppressing the use of commercial power in energy storage.

Incidentally, whether or not energy storage is necessary depends on the amount of power consumed. For example, if power consumption is not expected to be very high, it may not be necessary to actively use commercial power 14 for storage. For instance, on weekends in a factory that mainly operates on weekdays, power consumption may be significantly lower than on weekdays. Therefore, it is possible to check the power consumption, and if it is expected that power consumption will be low on that day, the system may be controlled to store any surplus solar power in the battery 11 instead of using commercial power for storage. On the other hand, if high power consumption is expected on that day, it is necessary to determine whether or not to use commercial power for storage and to control the system accordingly.

To enable this, the battery charging control system 1 is capable of measuring the power consumption of the load 12 during a reference time period t1 or a time period prior to reference time period t1. If the measured power consumption is above a threshold, the determination unit 16 determines whether the weather measurement data for reference time period t1 is above or below the threshold. If the measured power consumption is below the threshold, it is preferable to output a signal to the control unit to charge the battery 11 using the surplus solar power generation.

Here, the embodiment will be explained following the flow shown in Figure 4. In the example shown in Figure 4, first, it is determined whether the power consumption during the reference time period t1 is above a threshold (ST001). If the power consumption during the reference time period t1 is above the threshold, it is determined whether the power generation of the solar cell 13 is expected to be sufficient, in order to actively perform peak shaving on the power consumption for that day (ST002).

If it is determined in step 002 that the solar cell 13 is expected to generate sufficient power, the surplus solar power is used to charge the battery 11. Therefore, a calculation is performed to subtract the power consumed from the solar power to determine whether a surplus exists. Based on the derived value, it is determined whether or not there is a surplus in the solar power (ST003). If a surplus exists, the battery 11 is charged. If no surplus exists, the battery 11 is discharged so that the power can be used by the load 12.

In the example shown in Figure 4, even if the power consumption during the reference time period t1 in step 001 is below the threshold, the surplus solar power is used to charge the battery 11.

If it is determined in step 002 that the amount of power generated by the solar cell 13 is not expected to be sufficient, the battery 11 is charged using the commercial power supply 14 while power consumption is low. In the example shown in Figure 4, the charging speed required to charge the necessary amount by the target time t2 is calculated. More specifically, the charging speed is derived by dividing the total amount of charge required by the time from the end of the reference time period t1 to the target time t2 (ST004).

Subsequently, charging is performed according to the charging speed derived from the calculation, but it is determined during charging whether the target time t2 for securing the charge amount has been reached (ST005). If it is determined in step 005 that the target time t2 for securing the charge amount has been reached, charging to the battery 11 is stopped, and during the demand peak time that occurs after the target time t2, the battery 11 is discharged so that its power can be used by the load 12, thereby suppressing the use of the commercial power supply 14.

If it is not determined in step 005 that the target time t2 for securing the charge amount has been reached, it is determined whether the solar power generation exceeds the power consumption of load 12 and whether a surplus has occurred (ST006). If it is determined in step 006 that no surplus has occurred, charging of the battery 11 continues using only commercial power. If it is determined in step 006 that a surplus has occurred, both commercial power and surplus power are used to charge the battery 11. Here, the amount of surplus power used to charge the battery 11 is subtracted from the power supplied from the commercial power source 14 to the battery 11, and the charging speed of the battery 11 is controlled to maintain the value derived in step 004.

Incidentally, the determination unit 16 and the control unit may determine the estimated amount of electricity generated by the solar cell 13 in a different manner than the example described above, and then determine the amount of charge from the commercial power supply 14 to the storage battery 11 based on that estimated amount.

For example, the determination unit 16 uses "weather measurement data of weather information during the reference time period t1" and "predicted power consumption data of the load 12 after the reference time period t1" to determine whether there will be a surplus of PV power. If the determination result indicates that a surplus of PV power is expected, the system controls the charging of the battery 11 to begin using the surplus solar power until the target time t2. If the determination result from the determination unit 16 indicates that no surplus of PV power is expected, the system controls the charging of the battery 11 to begin using commercial power until the target time t2. Even in this way, it is possible to read the weather conditions from the measurement data and utilize the battery 11 efficiently.

Therefore, a battery charging control system 1, which includes a solar cell 13 capable of supplying generated solar power to a battery 11 and a load 12, a commercial power supply 14 capable of supplying commercial power to the battery 11 and the load 12, and a battery 11 capable of supplying charging power to the load 12, includes a weather measurement unit 15 capable of measuring at least one weather information such as solar radiation, humidity, and atmospheric pressure during a reference time period t1 and transmitting weather measurement data to a determination unit 16, and uses the weather measurement data of the weather information during the reference time period t1 and the predicted power consumption data of the load 12 after the reference time period t1 to determine the surplus solar power generation power. Preferably, the system includes a determination unit 16 capable of determining whether or not there will be a surplus in solar power generation, and a control unit capable of controlling the method of charging the battery 11. The control unit, if the determination unit 16 indicates that a surplus is expected in solar power generation, controls the system to begin charging the battery 11 with the surplus solar power generation until the target charging time t2. Conversely, if the determination unit 16 indicates that no surplus solar power generation is expected, it controls the system to begin charging the battery 11 with commercial power until the target charging time t2.

Furthermore, it is preferable to have a storage unit 21 that stores "past weather conditions in the reference time period t1," "past solar power generation data from the reference time period t1 onwards," and "past power consumption of the load 12 from the reference time period t1 onwards." This unit compares "solar power generation data from the reference time period t1 onwards for past days with similar weather conditions to the weather measurement data for the current day" with "power consumption of the load 12 measured at the same time as the solar power generation measurement." If the solar power generation is greater than the power consumption of the load 12, it is assumed that a surplus of solar power generation is expected, and if the solar power generation is less than the power consumption of the load 12, it is assumed that no surplus of solar power generation is expected, and therefore the system is controlled accordingly. This allows the determination unit 16 to predict the power consumption of the load 12 for that day with higher accuracy, thus enabling more accurate determination by the determination unit 16 using this predicted data.

The present invention has been described above using embodiments as examples, but the present invention is not limited to the above embodiments and can be implemented in various forms. For example, it is not necessary to control it in the manner of a flow. Of course, other controls can be combined, partially deleted, or rearranged, as long as they do not contradict the spirit of the invention. Furthermore, a control unit may be provided separately from the solar power conditioner control unit and the battery power conditioner control unit.

1. Battery charging control system 11. Battery 12. Load 13. Solar cell 14. Commercial power supply 15. Weather measurement unit 16. Judgment unit t1. Reference time period t2. Target time for securing charge amount t3. Desired final time for using stored energy.

Claims (3)

A battery charging control system comprising a solar cell capable of supplying generated solar power to a battery and a load, a commercial power source capable of supplying commercial power to a battery and a load, and a battery capable of supplying charging power to a load, wherein the solar cell is connected to the battery.
A weather measurement unit capable of measuring at least one weather information item, such as solar radiation, humidity, and atmospheric pressure, during a reference time period, and transmitting the weather measurement data to a judgment unit,
A determination unit capable of determining whether weather measurement data during a reference time period is above or below a threshold,
A control unit capable of controlling how the battery is charged,
Equipped with,
The control unit is
If the determination unit determines that sufficient power generation from the solar panels is expected, it will begin controlling the system to charge the battery using the surplus solar power until the target time for securing the charge amount.
If the judgment unit determines that sufficient power generation from the solar panels is not expected, it will start controlling the system to charge the battery using commercial power until the target time for securing the charge level .
It is possible to measure the power consumption of the load during the standard time period or a time period earlier than the standard time period.
If the measured power consumption is above the threshold, the determination unit determines whether the weather measurement data for the reference time period is above or below the threshold.
A battery charging control system that, when the measured power consumption is below a threshold, outputs a signal to the control unit to charge the battery using surplus solar power . A battery charging control system comprising a solar cell capable of supplying generated solar power to a battery and a load, a commercial power source capable of supplying commercial power to a battery and a load, and a battery capable of supplying charging power to a load, wherein the solar cell is connected to the battery.
A weather measurement unit capable of measuring at least one weather information item, such as solar radiation, humidity, and atmospheric pressure, during a reference time period, and transmitting the weather measurement data to a judgment unit,
A determination unit capable of determining whether weather measurement data during a reference time period is above or below a threshold,
A control unit capable of controlling how the battery is charged,
Equipped with,
The control unit is
If the determination unit determines that sufficient power generation from the solar panels is expected, it will begin controlling the system to charge the battery using the surplus solar power until the target time for securing the charge amount.
If the judgment unit determines that sufficient power generation from the solar panels is not expected, it will start controlling the system to charge the battery using commercial power until the target time for securing the charge level .
If the determination unit determines that the weather measurement data for the reference time period is below the threshold,
A battery charging control system that controls the discharge rate in the control unit so that the discharge rate from the battery to the load remains constant from a predetermined time after the target time for securing the charge amount until the final time of desired use of the stored energy, and so that the charge amount of the battery reaches a set value at the final time of desired use of the stored energy. A battery charging control system comprising a solar cell capable of supplying generated solar power to a battery and a load, a commercial power source capable of supplying commercial power to a battery and a load, and a battery capable of supplying charging power to a load, wherein the solar cell is connected to the battery.
A weather measurement unit capable of measuring at least one weather information item, such as solar radiation, humidity, and atmospheric pressure, during a reference time period, and transmitting the weather measurement data to a judgment unit,
A determination unit capable of determining whether there will be a surplus of solar power generation power using weather measurement data of weather information during a reference time period and predicted power consumption data of the load after the reference time period,
A control unit capable of controlling how the battery is charged,
Equipped with,
The control unit is
If the determination unit determines that there is a surplus of solar power, it controls the system to start charging the battery with the surplus solar power until the target time for securing the charge amount.
If the determination unit determines that no surplus solar power is expected, the system will control the battery to begin charging using commercial power until the target time for securing the charge amount .
It includes a storage unit that stores past weather conditions during a reference time period, past solar power generation since the reference time period, and past load power consumption since the reference time period.
The weather measurement data for the day during the reference time period is compared with the solar power generated during the reference time period on past days with similar weather conditions, and the power consumption of the load measured at the same time as the measurement of the said solar power generation.
If the amount of electricity generated by solar power is greater than the amount of electricity consumed by the load, the system will be controlled assuming that there will be a surplus of solar power.
A battery charging control system that controls the system based on the assumption that there will be no surplus solar power if the amount of solar power generated is less than the amount of power consumed by the load .