JP5186446B2 - Discharge control device, uninterruptible power supply, and load leveling system - Google Patents

Description

  The present invention relates to a secondary battery discharge control technique.

  When discharging a secondary battery, there is an application in which the remaining capacity of the secondary battery needs to be secured to a predetermined value or more. As an example of such an application, there is an uninterruptible power supply device disclosed in Patent Document 1, for example. This uninterruptible power supply stores the power of AC commercial power at night and controls the stored power in the daytime while controlling the stored power amount of the power storage means not to fall below the reference stored power amount. By supplying the load of the power supply device, the nighttime power of the AC commercial power supply is shifted in the daytime. In this uninterruptible power supply, the stored power amount of the power storage means is ensured to be at least equal to or higher than the reference stored power amount, so the power failure compensation function that is the original function of the uninterruptible power supply device is not lost.

JP 2000-278866 A

  Of the stored electric energy stored in the secondary battery, the dischargeable capacity (dischargeable capacity) varies depending on the ambient temperature of the secondary battery. That is, since the internal resistance of the secondary battery increases at a low temperature, the dischargeable capacity decreases as the ambient temperature decreases. Therefore, when the secondary battery is discharged, even if the remaining capacity of the secondary battery is secured to a predetermined value or more, the remaining capacity does not necessarily become a dischargeable capacity. For example, in the uninterruptible power supply described in Patent Document 1, since the reference stored power amount is constant regardless of the level of the ambient temperature, not all of the reference stored power amount is a dischargeable capacity. There is a risk that the capacity of power necessary for power failure compensation cannot be discharged at low temperatures.

  The present invention has been made to solve such a conventional problem, and discharges the secondary battery while leaving the necessary dischargeable power regardless of the ambient temperature of the secondary battery. The purpose is to let you.

A discharge control device according to one aspect of the present invention includes a temperature measurement unit that measures the ambient temperature of a secondary battery that stores power supplied from an external power source, and a remaining capacity calculation that calculates a remaining capacity of the secondary battery. Means, storage means for storing the first capacity, and control means for controlling the discharge of the secondary battery, the control means, the remaining capacity, the first capacity and the first capacity The first capacity is changed according to the ambient temperature measured by the temperature measuring means, and the remaining capacity becomes the first capacity. In the discharge control device for stopping the discharge of the secondary battery at a point in time, the apparatus further comprises a temperature change prediction means for predicting a time change of the ambient temperature, and the storage means further includes a schedule for charging and discharging the secondary battery. Storing the remaining capacity calculating means, Pond calculates the remaining capacity corresponding to the ambient temperature of the time zone to be discharged.

According to this configuration , the remaining capacity secured without being discharged when the secondary battery is discharged is changed according to the ambient temperature of the secondary battery. Therefore, the secondary battery can ensure that a required amount of power can be discharged even at low temperatures. In addition, since the first capacity is secured according to the ambient temperature of the time zone during which the secondary battery is discharged, the first capacity that is secured without discharging at the time of discharging is used in an actual usage mode. It can be calculated together.

In the above configuration , the storage unit stores a plurality of values set according to changes in the ambient temperature as the first capacity, and the control unit is configured to select the temperature measurement unit from the plurality of values. It is desirable that the first capacity is changed according to the ambient temperature measured by the temperature measuring means by selecting a value corresponding to the measured ambient temperature.

According to this configuration , the first capacity that is secured without discharging when the secondary battery is discharged is selected from a plurality of values that are set according to changes in the ambient temperature. Therefore, the first capacity can be changed reliably.

In the above configuration , the battery further includes a discharge amount calculating unit that calculates a discharge amount of the secondary battery, and the storage unit further stores a charge completion capacity that is a capacity when the secondary battery is completely charged, and the remaining capacity The calculating means preferably calculates the remaining capacity by subtracting the discharge amount calculated by the discharge amount calculating means from the charge completion capacity.

According to this configuration , the remaining capacity can be accurately calculated, and thus the first capacity secured in the secondary battery as dischargeable power can be accurately calculated.

In the above configuration , the storage unit stores a plurality of values set according to the number of charge / discharge cycles of the secondary battery as the charge completion capacity, and the remaining capacity calculation unit is configured to discharge the secondary battery. , the value of the charging completion capacity corresponding to the number of charge-discharge cycles when the discharge, it is desirable to calculate the remaining capacity selected and used from among the plurality of values.

According to this configuration , the remaining capacity can be accurately calculated even when the secondary battery deteriorates and the charge completion capacity decreases.

In the above-described configuration , the battery pack further includes charge completion capacity changing means for changing the charge completion capacity stored in the storage means, and the remaining capacity calculating means uses the charge completion capacity changed by the charge completion capacity changing means. It is desirable to calculate the remaining capacity.

According to this configuration, when the secondary battery is deteriorated and the charge completion capacity is decreased, the charge completion capacity is changed by the charge completion capacity changing unit. Therefore, the remaining capacity can be accurately calculated even when the secondary battery deteriorates and the charge completion capacity decreases.

A discharge control device according to another aspect of the present invention includes a temperature measuring unit that measures the ambient temperature of a secondary battery that stores power supplied from an external power source, and a remaining capacity calculator that calculates a remaining capacity of the secondary battery. Means, storage means for storing the first capacity, and control means for controlling the discharge of the secondary battery, the control means, the remaining capacity, the first capacity and the first capacity The first capacity is changed according to the ambient temperature measured by the temperature measuring means, and the remaining capacity becomes the first capacity. In the discharge control device for stopping the discharge of the secondary battery at the time, the discharge amount calculation means for calculating the discharge amount of the secondary battery, and the charge completion capacity for changing the charge completion capacity stored in the storage means Change means, and the storage means A charge completion capacity that is a capacity at the time of battery charge completion and a charge / discharge schedule of the secondary battery are further stored, and the remaining capacity calculation unit calculates the discharge amount calculated by the discharge amount calculation unit. The remaining capacity is calculated by subtracting from the charge completion capacity, and the remaining capacity is calculated using the charge completion capacity changed by the charge completion capacity changing means, and the control means is predetermined. The secondary battery is completely discharged after completion of charging at the time, the discharge amount calculating means calculates the discharge amount at the time of the complete discharge, and the charge completion capacity changing means is replaced with a previously stored charge completion capacity. The discharge amount at the time of the complete discharge is stored in the storage means as the charge completion capacity, further comprising a temperature change prediction means for predicting a time change of the ambient temperature, Capacity calculating means calculates the remaining capacity corresponding to the ambient temperature of the time zone in which the secondary battery is discharged.

According to this configuration , the charge completion capacity can be updated regularly and automatically according to the degree of deterioration of the secondary battery. In addition, since the first capacity is secured according to the ambient temperature of the time zone during which the secondary battery is discharged, the first capacity that is secured without discharging at the time of discharging is used in an actual usage mode. It can be calculated together.

In the above configuration , the temperature measuring unit measures the ambient temperature at a predetermined interval, and the storage unit further stores the ambient temperature measured during the period, and the temperature change The predicting means preferably predicts the ambient temperature in a time zone in which the secondary battery is discharged based on the ambient temperature stored in the storage means.

According to this configuration , it is possible to predict the ambient temperature in the time zone in which the secondary battery is discharged based on the temperature change in the installation environment of the discharge control device.

An uninterruptible power supply according to still another aspect of the present invention includes the above discharge control device, and a secondary battery that is controlled by the discharge control device and stores electric power supplied from an external power source, and the external When the power supply stops, power is supplied to the load using at least one of the first capacity power and the second capacity power stored in the secondary battery.

According to this configuration , power more than the first capacity is stored in the secondary battery, so that power failure compensation can be reliably performed.

A load leveling system according to still another aspect of the present invention includes the above-described uninterruptible power supply, and uses only the second capacity power stored in the secondary battery during load leveling operation. To supply power.

According to this configuration , power equal to or higher than the first capacity is stored in the secondary battery, so that load leveling can be performed without losing the function of the uninterruptible power supply.

The above configuration further includes power consumption measuring means for measuring the power consumption of the load, and supplies power from the secondary battery to the load when the power consumption exceeds a predetermined power value. It is desirable .

According to this configuration , load leveling can be performed when the power consumption of the load exceeds a predetermined power value, so that more effective load leveling can be performed.

  According to the present invention, regardless of the ambient temperature of the secondary battery, the secondary battery can ensure that the required capacity of electric power can be discharged. Therefore, the present invention is suitable for application to, for example, applications that require both load leveling and power failure compensation.

It is a block diagram which shows the outline of the load leveling system which concerns on one Embodiment of this invention. It is a figure which shows the relationship between battery ambient temperature and a power failure compensation capacity. It is a flowchart which shows the control which the uninterruptible power supply device with which the load leveling system which concerns on one Embodiment of this invention is equipped performs load leveling and power failure compensation. It is a flowchart which shows the control which the uninterruptible power supply with which the load leveling system which concerns on one Embodiment of this invention is provided performs when the power consumption of load exceeds the predetermined electric power value. It is a block diagram which shows the outline of the load leveling system which concerns on the deformation | transformation embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an outline of a load leveling system 1 according to an embodiment of the present invention. In the load leveling system 1, the uninterruptible power supply 20 is connected to the external power supply 2, and the load 3 is connected to the uninterruptible power supply 20 and the external power supply 2.

  The uninterruptible power supply 20 includes a discharge control device 10 and a secondary battery 200. The uninterruptible power supply 20 receives power from an external power source 2 that is a commercial power source, for example, stores power in a secondary battery 200 that is a lithium ion battery, for example, and uses this stored power to perform load leveling and power outage Compensate.

  The uninterruptible power supply 20 includes a switch 170 that enables disconnection from the external power supply 2. At the time of standby of the uninterruptible power supply 20 and load leveling, the control unit 100 turns on the switch 170 to enable power supply from the external power source 2 to the load 3. When the uninterruptible power supply 20 is on standby, power is supplied from only the external power supply 2 to the load 3, and during load leveling operation, the secondary battery 200 is supplied by the uninterruptible power supply 20 in addition to supplying power from the external power supply 2. The electric power stored in is also supplied to the load 3. At the time of power failure compensation, the control unit 100 turns off the switch 170 and supplies the power stored in the secondary battery 200 to the load 3 in order to prevent a reverse power flow to the external power supply 2 side that is a commercial power system. The control unit 100 will be described in detail later.

  Note that the load leveling by the uninterruptible power supply 20 is a load leveling time zone, which is a time zone during which the power consumption of the load 3 increases, or the value of the power consumption exceeds a predetermined threshold value Wth. If done either.

  The discharge control device 10 includes a control unit 100 (control unit), a temperature sensor 120 (temperature measurement unit), a current / voltmeter 130, a wattmeter 140 (power consumption measurement unit), an AC / DC converter 150, an interconnection reactor 160, And the switch 170 described above.

  The temperature sensor 120 is installed in the vicinity of the secondary battery 200 and measures the ambient temperature of the secondary battery 200. The ammeter / voltmeter 130 measures a discharge current value and a discharge voltage value of electric power discharged from the secondary battery 200 when the secondary battery 200 is discharged. The wattmeter 140 measures the amount of power used by the load 3.

  The AC / DC converter 150 functions as a rectifier that converts AC power supplied from the external power source 2 into DC power and supplies the DC power to the secondary battery 200 when the secondary battery 200 is charged. The inverter functions as an inverter that converts the DC power discharged from the secondary battery 200 into AC power having a voltage value, current value, or power value corresponding to the load 3 and supplies the AC power to the load 3. Further, the AC / DC converter 150 uses the electric power supplied from the external power supply 2 to charge the secondary battery 200 by, for example, a constant voltage / constant current charging method.

The interconnecting reactor 160 is provided between the AC / DC converter 150 and the external power supply 2. Load leveling behavior at the time of the AC-DC converter 150, AC-DC conversion unit 150 side of the AC power V ₂ phase that also advancing from the external power source 2 side of the AC power V ₁ of the phase stored in the secondary battery 200 The supplied power is supplied to the load 3. When the secondary battery 200 is charged, the AC / DC converter 150 supplies the power of the external power source 2 to the secondary battery 200 by delaying the phase of V _{2 from} the phase of V ₁ . When AC / DC converter 150 equalizes the phase of V _{2 and} the phase of V ₁ , secondary battery 200 enters a standby state in which neither charging nor discharging is performed.

  The control unit 100 includes a CPU (Central Processing Unit) 110, a time measuring unit 101, and a storage unit 102 (storage means).

The storage unit 102 includes, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. capacity C0, the threshold Wth, and stores a table relating such ambient temperature of the secondary battery 200 and the power failure and the compensating capacitance C _1. The charge / discharge schedule includes information on the start time and end time of a preset load leveling time zone. It should be noted, will be described in detail later a power failure compensation capacitor C _1.

  The timer unit 101 includes a clock transmitter that generates a clock signal at a constant period, and outputs the clock signal to the CPU 110. Based on the clock signal and the charge / discharge schedule stored in the storage unit 102, the discharge control unit 111, the charge control unit 112, and the charge / discharge switching instruction unit 113, which will be described later, are in a time zone for performing load leveling. Determine.

  The CPU 110 executes the discharge control program stored in advance in the storage unit 102, whereby a discharge control unit 111, a charge control unit 112, a charge / discharge switching instruction unit 113, and a discharge amount calculation unit 114 (discharge amount calculation means). The remaining capacity calculation unit 115 (remaining capacity calculation unit), the power failure compensation capacity management unit 116, and the charge completion capacity change unit 117 (charge completion capacity change unit) function as software. It should be noted that each of the above-described units can be provided inside the CPU 110 as hardware.

  The discharge control unit 111 supplies the load 3 to the load 3 based on at least one of the measurement values measured by the current / voltmeter 130 and the wattmeter 140 when the secondary battery 200 is discharged, that is, during power failure compensation or load leveling. At least one of a voltage value and a current value of the AC power to be performed and a power value is determined. Then, the discharge control unit 111 controls the AC / DC conversion unit 150 so that the power supplied to the load 3 becomes the AC power having the value thus determined.

Based on the current value and voltage value of the secondary battery 200 measured by the current / voltmeter 130, the charging control unit 112 is a current value that the AC / DC conversion unit 150 applies to the secondary battery 200 when the secondary battery 200 is charged. And determine the voltage value. The charging control unit 112 instructs the AC / DC conversion unit 150 to charge until the charging end condition is satisfied, that is, (1) until the remaining capacity of the secondary battery 200 reaches the charging completion capacity C ₀ . (2) When the voltage value of the secondary battery 200 is equal to or higher than the predetermined threshold value Vth1, (3) When the secondary battery 200 is charged until the predetermined charging time Tth, until either of the cases, The secondary battery 200 is charged with the current value and the voltage value. Incidentally, Vth1 and Tth are also previously stored in the storage unit 102 and _{C 0.}

  The charge / discharge switching instruction unit 113 determines whether to charge or discharge the secondary battery 200 based on the charge / discharge schedule stored in the storage unit 102 and the clock signal output from the time measuring unit 101, and performs AC / DC conversion. The unit 150 is instructed to switch between charge and discharge.

  The discharge amount calculation unit 114 samples the current value measured by the current / voltmeter 130 at a predetermined interval when the secondary battery 200 is discharged based on the clock signal output from the time measuring unit 101, and integrates the current value. By doing so, the discharge amount (unit: Ah) of the secondary battery 200 is calculated.

The remaining capacity calculation unit 115 calculates the remaining capacity of the secondary battery 200 by subtracting the discharge amount calculated by the discharge amount calculation unit 114 from the charge completion capacity C ₀ stored in the storage unit 102. In this way, the remaining capacity calculation unit 115 calculates the remaining capacity, so that the remaining capacity is accurately calculated as compared with the case where the remaining capacity is calculated based on the discharge voltage value of the secondary battery 200, for example. Can do.

The power failure compensation capacity management unit 116 converts the remaining capacity calculated by the remaining capacity calculation unit 115 into a power failure compensation capacity C ₁ (first capacity) and a load leveling capacity C ₂ (second capacity). Divide and manage. Power failure compensating capacitance C ₁ is at the time of load leveling for use in a power failure compensation is amount of space without being discharged. Load leveling capacitor C ₂ is the capacitance obtained by subtracting the power failure compensating capacitor C ₁ from the remaining capacity, used in applications of the load leveling. A table stored in the storage unit 102 that associates the ambient temperature of the secondary battery 200 with the power failure compensation capacity C ₁ , the power failure compensation capacity management unit 116 measures the temperature sensor 120. wherein changing the power failure compensating capacitor C ₁ in response to ambient temperature and. In this table, as the ambient temperature of the secondary battery 200 is low, power failure compensating capacitance C ₁ to increases, both are associated.

Since the said remaining capacity is managed, the discharge control unit 111, when the load leveling, the discharge of the secondary battery 200 when the remaining capacity of the secondary battery 200 becomes a power failure compensating capacitor C ₁ Stop. Further, at the time of power failure compensation, the discharge control unit 111 uses the power failure compensation capacity C ₁ to discharge the secondary battery 200 when the load leveling capacity C ₂ is used up.

The charging completion capacity changing unit 117 changes the charging completion capacity C ₀ stored in the storage unit 102. This change will be described below. The discharge control unit 111 completely discharges the secondary battery 200 after the completion of charging at a predetermined time based on the charge / discharge schedule stored in the storage unit 102 in advance. The charge completion capacity changing unit 117 replaces the discharge amount at the time of complete discharge calculated by the discharge amount calculation unit 114 with the charge completion capacity C ₀ stored in advance, and stores it as a new charge completion capacity C ₀ ′. 102.

As described above, the charge completion capacity changing unit 117 periodically and automatically updates the charge completion capacity C ₀ as an actual measurement value corresponding to the degree of deterioration of the secondary battery 200. Therefore, even when the secondary battery 200 repeats the charge / discharge cycle or the secondary battery 200 is deteriorated over time, the charge completion capacity C ₀ is decreased from the initial value (see FIG. 2, see the initial value C ₀ ). , C ₀ ′ after reduction, the remaining capacity calculation unit 115 can accurately calculate the remaining capacity of the secondary battery 200 using the new charge completion capacity C ₀ ′.

FIG. 2 is a diagram showing a relationship between the ambient temperature of the secondary battery 200 and the power failure compensation capacity C1. In the internal resistance of the rechargeable battery 200 is increased at low temperature, the amount of storage power stored in the secondary battery 200 discharges non space occupied in (= remaining capacity. Is fully charged capacitor C ₀ in FIG. 2) The ratio of (non-dischargeable capacity Cd) increases as the ambient temperature of the secondary battery 200 decreases. That is, the ratio of the dischargeable capacity occupying the charge completion capacitance C ₀ of the rechargeable battery 200 (dischargeable capacity Ce) becomes smaller as the ambient temperature of the secondary battery 200 is low. Since the amount of power required for power failure compensation (necessary compensation capacity Ck) is constant regardless of the ambient temperature, the power failure compensation capacity C ₁ (= Cd + Ck) increases as the ambient temperature of the secondary battery 200 decreases. . The said table associating ambient temperature of the secondary battery 200 and the power failure and the compensating capacitor C _1, such relationship is reflected.

The power failure compensation capacity management unit 116 refers to the table and changes the power failure compensation capacity C ₁ according to the ambient temperature measured by the temperature sensor 120. Therefore, the secondary battery 200 is required compensation capacity even at low temperatures. Ck can be discharged. That is, at the time of power failure compensation, the discharge control unit 111 discharges the secondary battery 200 using the power failure compensation capacity C ₁ when the load leveling capacity C ₂ is used up and cannot discharge from the power failure compensation capacity C _1. The power failure compensation is continued unless the necessary compensation capacity Ck excluding the capacity Cd is used up. Note that the determination condition when the discharge control unit 111 determines that the necessary compensation capacity Ck has been used is that the discharge voltage value of the secondary battery 200 measured by the current / voltmeter 130 is equal to or less than a predetermined threshold value Vth2 (V). It is to become. The threshold value Vth2 is stored in the storage unit 102 in advance.

  FIG. 3 is a flowchart showing the control performed by the uninterruptible power supply 20 included in the load leveling system 1 at the time of load leveling and power failure compensation. When the uninterruptible power supply 20 is activated, the control unit 100 monitors whether power is normally supplied from the external power supply 2 (step S1). When the power supply from the external power supply 2 is stopped (YES in step S1), the process proceeds to step S11, and the uninterruptible power supply 20 starts power failure compensation. When power is normally supplied from the external power supply 2 (NO in step S1), the control unit 100 monitors whether or not the power consumption of the load 3 measured by the wattmeter 140 is equal to or less than the threshold value Wth (step). S2).

If the power consumption exceeds Wth (NO in step S2), the process proceeds to circled number 1 in FIG. When the power consumption is less than or equal to Wth (YES in step S2), the control unit 100 determines that the time is load leveling based on the charge / discharge schedule stored in the storage unit 102 and the clock signal output from the time measuring unit 101. It is determined whether or not it is a time period (step S3). When it is the load leveling time zone (YES in step S3), the power failure compensation capacity management unit 116 calculates the power failure compensation capacity C ₁ based on the ambient temperature of the secondary battery 200 measured by the temperature sensor 120. (Step S4). Moreover, the remaining capacity calculation unit 115 calculates the remaining capacity of the secondary battery 200 (step S5). If it is not the load leveling time zone (NO in step S3), the process proceeds to step S15.

If the remaining capacity is greater than the power failure compensating capacitor C ₁ (YES in step S6), and the uninterruptible power supply 20 starts the load leveling (step S7). If the remaining capacity is a power failure compensating capacitor _{C 1} or less (NO in step S6), the process proceeds to step S17.

Without using up the load leveling capacitor C _2, if i.e. the remaining capacity in the load leveling is not a power failure compensating capacitor C ₁ (YES in step S8), and became a load leveling end time (step The uninterruptible power supply 20 ends load leveling (step S10) and starts charging the secondary battery 200 (step S18). Used up load leveling capacitor C ₂ in load leveling, when the remaining capacity becomes a power outage compensating capacitor C ₁ (NO in step S8), and the uninterruptible power supply 20 is terminated load leveling (Step S16).

  At the time of power failure compensation started in step S11, the necessary compensation capacity Ck is not used up, that is, the discharge voltage value of the secondary battery 200 does not become the threshold value Vth2 or less (YES in step S12), and the power supply from the external power source 2 is restored. If the required compensation capacity Ck is used up, that is, if the discharge voltage value of the secondary battery 200 is equal to or lower than the threshold value Vth2 (NO in step S12), the uninterruptible power supply 20 The power failure compensation is terminated (step S14).

When the power failure compensation is finished (step S14), and or load leveling in load leveling time zone, when the remaining capacity of the secondary battery 200 is terminated due to a power failure compensating capacitor C ₁ (step S16) is Then, waiting for the end of the load leveling time zone (NO in step S17), the charging control unit 112 starts charging the secondary battery 200 (step S18). The reason why the charging control unit 112 starts charging the secondary battery 200 after the end of the load leveling time zone is that the power consumption of the load 3 is large in the load leveling time zone (YES in step S17). This is because when the charging of the secondary battery 200 is started, the load of the external power source 2 further increases, which is against the purpose of load leveling.

Proceeds to step S15 if NO in step S3, even when the remaining capacity of the secondary battery 200 is less than the charge completion capacitance _{C 0} (NO at step S15), and the charging control unit 112 proceeds to step S18, secondary Charging of the battery 200 is started.

Proceeding to step S15, when the remaining capacity of the secondary battery 200 is the charge completion capacity C _0, that is, when the secondary battery 200 is not discharged after the completion of charging (YES in step S15), the process proceeds to step S21 and the uninterruptible power is lost. The power supply device 20 enters a standby state.

  In step S18, charging of the secondary battery 200 is started, and when the secondary battery 200 is charged until the charging end condition is satisfied (YES in step S19), the charging control unit 112 charges the secondary battery 200. Is terminated (step S20), and the uninterruptible power supply 20 enters a standby state (step S21).

  FIG. 4 is a flowchart showing the control performed when the uninterruptible power supply 20 included in the load leveling system 1 performs when the power consumption of the load 3 exceeds the threshold value Wth. When power is normally supplied from the external power source 2 (NO in step S1, see FIG. 3), when the power consumption of the load 3 measured by the wattmeter 140 exceeds Wth (NO in step S2) The power failure compensation capacity management unit 116 calculates the power failure compensation capacity C1 based on the ambient temperature of the secondary battery 200 measured by the temperature sensor 120 (step S101). Further, the remaining capacity calculation unit 115 calculates the remaining capacity of the secondary battery 200 (step S102).

If the load leveling capacitor C ₂ is not used up, i.e. when the remaining capacity exceeds a power failure compensating capacitor C1 (YES at step S103), the uninterruptible power supply 20 starts the load leveling (step S104). If the load leveling capacitor C ₂ is used up, i.e. the if the remaining capacity of the power failure compensating capacitor C ₁ or less (NO in step S103), the process proceeds to encircled numeral 2 in FIG. 3, load leveling time Waiting for the end of the band (NO in step S17, see FIG. 3), the charging control unit 112 starts charging the secondary battery 200 (see step S18, FIG. 3).

Without load leveling capacitor C ₂ is used up, i.e. not the remaining capacity in the load leveling power outage compensating capacitor C ₁ (NO in step S105), the power consumption of the load 3 to the power meter 140 was measured Is equal to or less than Wth (YES in step S106), uninterruptible power supply 20 ends load leveling (step S107). Load leveling capacitor C ₂ in load leveling used up, when the remaining capacity has decreased to a power failure compensating capacitance C1 (YES at step S105), the process proceeds to circled numeral 3 in FIG. 3, the uninterruptible The power supply device 20 ends the load leveling (see step S16, FIG. 3).

Incidentally, when the as power consumption of the load 3 to the power meter 140 is measured during the load leveling exceeds Wth (NO at step S106), the process returns to step S105, the capacitance _{C 2} is for load leveling not used up as long, that is to continue the load leveling as long as the remaining capacity is not a power failure compensating capacitance C _1.

When the power consumption of the load 3 is less than Wth and the load leveling is finished (step S107), if it is not the load leveling time zone (NO in step S108), the process proceeds to the circled number 4 in FIG. 112 starts charging the secondary battery 200 (step S18, see FIG. 3). If it is the load leveling time zone (YES in step S108), the process proceeds to circled number 5 in FIG. 3 and the power management unit 116 for power failure compensation measures the secondary battery measured by the temperature sensor 120 in preparation for load leveling. 200 calculates a power failure compensating capacitor _{C 1,} based on the ambient temperature (see step S4, FIG. 3).

According to the load leveling system 1 according to the above-described embodiment, the power failure compensation capacity management unit 116 refers to the table, and determines the power failure compensation capacity C ₁ according to the ambient temperature measured by the temperature sensor 120. Therefore, the secondary battery 200 can discharge the necessary compensation capacity Ck even at a low temperature.

The load leveling system 1 according to the embodiment of the present invention has been described above. However, the present invention is not limited to this, and for example, the following modified embodiment can be taken.

(1) In the above embodiment, based on the charging / discharging schedule of the secondary battery 200, the discharge control unit 111 completely discharges the secondary battery 200 after completion of charging at a predetermined time point, and the charge completion capacity changing unit 117 stores the discharge amount at the time of the complete discharge in the storage unit 102 as a new charge completion capacity C ₀ ′. Instead, a table that associates the number of charge / discharge cycles of the secondary battery 200 with the charge completion capacity C ₀ is stored in the storage unit 102, and the remaining capacity calculation unit 115 performs the discharge when the secondary battery 200 is discharged. The remaining capacity may be calculated using the value of the charge completion capacity C ₀ corresponding to the number of charge / discharge cycles at the time selected from the table. According to this configuration, when the secondary battery 200 deteriorates and the charge completion capacity C ₀ decreases, the remaining capacity of the secondary battery 200 can be accurately calculated without actually measuring the charge completion capacity C _0. .

(2) In the above embodiment, the control unit 100 calculates the power failure compensation capacity C ₀ corresponding to the battery ambient temperature at the start of load leveling. Instead, a temperature change prediction unit 118 (temperature change prediction means) is provided in the control unit 100 as shown in FIG. 5, and the load is determined based on the charge / discharge schedule of the secondary battery 200 stored in the storage unit 102. The temperature change predicting unit 118 predicts the time-dependent change in the battery ambient temperature in the leveling time zone, and the power failure compensation capacity management unit 116 calculates the power failure compensation capacity C0 corresponding to the minimum value of the battery ambient temperature in the time change. You may make it do.

  For example, the temperature change prediction unit 118 samples the ambient temperature measured by the temperature sensor 120 at a predetermined interval, for example, every few minutes in the load leveling time period, and determines the ambient temperature measurement data in advance. For example, the temperature change predicting unit 118 stores the ambient temperature in the load leveling time zone based on the average value of the ambient temperature and the tendency of change over time. Can be predicted.

  Further, for example, the load leveling system 1 is connected to the network, and the temperature change prediction unit 118 acquires the weather forecast data of the area where the load leveling system 1 is installed from an external database, thereby performing the load leveling. It is also possible for the temperature change predicting unit 118 to predict the minimum value of the battery ambient temperature in the displayed time zone.

  According to these configurations, the capacity for power failure compensation corresponding to the lowest value of the battery ambient temperature in the load leveling time zone in which the secondary battery 200 is actually discharged is changed to the temperature change in the installation environment of the load leveling system 1. It can be ensured based on this, and can be set to an optimum value according to the fluctuation of the ambient temperature in the load leveling time zone.

(3) In the above embodiment, the power failure compensation capacity C ₁ corresponding to the battery ambient temperature measured by the temperature sensor 120 is stored in the storage unit 102 as a table. Alternatively, stores the battery ambient temperature capable of calculating formulas power outage compensating capacitance C ₁ in the storage unit 102, the control unit 100 by using the calculation formula, the battery ambient temperature the temperature sensor 120 is measured it may be calculated outage compensating capacitor C ₁ corresponding.

(4) In the above embodiment, the charge completion capacity changing section 117, the charge completion capacitance C ₀ is updated regularly and automatically. Instead, for example, an input unit that allows the user to input a charge completion capacity is provided, and the input value to the input unit is updated by the charge completion capacity change unit 117 as a new charge completion capacity C ₀ ′. Also good.

  (5) In the above embodiment, a lithium ion battery is used as the secondary battery 200 for storing electric power. However, other secondary batteries such as a nickel metal hydride battery can be used instead.

1 load leveling system 2 external power source 3 load 10 discharge control device 20 uninterruptible power supply 100 control unit (control means)
101 Timekeeping section 102 storage section (storage means)
110 CPU
111 discharge control unit 112 charge control unit 113 charge / discharge switching instruction unit 114 discharge amount calculation unit (discharge amount calculation means)
115 remaining capacity calculation unit (remaining capacity calculation means)
116 Capacity management unit for power failure compensation 117 Charging completion capacity changing unit (charging completion capacity changing means)
118 Temperature change prediction unit (temperature change prediction means)
120 temperature sensor (temperature measuring means)
140 Wattmeter (Power consumption measuring means)
200 secondary battery

Claims (10)

Temperature measuring means for measuring the ambient temperature of the secondary battery that stores power supplied from an external power source;
A remaining capacity calculating means for calculating a remaining capacity of the secondary battery;
Storage means for storing a first capacity;
Control means for controlling the discharge of the secondary battery,
The control means includes
Managing the remaining capacity by dividing it into a first capacity and a second capacity excluding the first capacity;
Changing the first capacity according to the ambient temperature measured by the temperature measuring means;
In the discharge control device for stopping discharge of the secondary battery when the remaining capacity becomes the first capacity ,
A temperature change predicting means for predicting a time change of the ambient temperature;
The storage means further stores a charge / discharge schedule of the secondary battery,
The remaining capacity calculating means calculates the remaining capacity corresponding to an ambient temperature in a time zone in which the secondary battery is discharged . The storage means stores a plurality of values set according to changes in the ambient temperature as the first capacity,
The control means selects a value corresponding to the ambient temperature measured by the temperature measurement means from the plurality of values, thereby changing the first capacity to the ambient temperature measured by the temperature measurement means. The discharge control device according to claim 1 which changes according to it. A discharge amount calculating means for calculating a discharge amount of the secondary battery;
The storage means further stores a charge completion capacity that is a capacity when the secondary battery is fully charged,
The discharge control device according to claim 1, wherein the remaining capacity calculation unit calculates the remaining capacity by subtracting the discharge amount calculated by the discharge amount calculation unit from the charge completion capacity. The storage means stores a plurality of values set according to the number of charge / discharge cycles of the secondary battery as the charge completion capacity,
When the secondary battery is discharged, the remaining capacity calculating means selects the value of the charge completion capacity corresponding to the number of charge / discharge cycles at the time of discharging from the plurality of values and uses the remaining capacity. The discharge control device according to claim 3 which computes. Charging completion capacity changing means for changing the charging completion capacity stored in the storage means,
The discharge control device according to claim 3, wherein the remaining capacity calculation unit calculates the remaining capacity using the charge completion capacity changed by the charge completion capacity change unit. Temperature measuring means for measuring the ambient temperature of the secondary battery that stores power supplied from an external power source;
A remaining capacity calculating means for calculating a remaining capacity of the secondary battery;
Storage means for storing a first capacity;
Control means for controlling the discharge of the secondary battery,
The control means includes
Managing the remaining capacity by dividing it into a first capacity and a second capacity excluding the first capacity;
Changing the first capacity according to the ambient temperature measured by the temperature measuring means;
In the discharge control device for stopping discharge of the secondary battery when the remaining capacity becomes the first capacity,
A discharge amount calculating means for calculating a discharge amount of the secondary battery;
Charging completion capacity changing means for changing the charging completion capacity stored in the storage means,
The storage means further stores a charge completion capacity that is a capacity at the completion of charging of the secondary battery, and a charge / discharge schedule of the secondary battery,
The remaining capacity calculation means calculates the remaining capacity by subtracting the discharge amount calculated by the discharge amount calculation means from the charge completion capacity, and uses the charge completion capacity changed by the charge completion capacity change means. To calculate the remaining capacity,
The control means completely discharges the secondary battery after completion of charging at a predetermined time point,
The discharge amount calculating means calculates a discharge amount during the complete discharge,
The charge completion capacity changing unit is configured to store the discharge amount at the time of the complete discharge in the storage unit as the charge completion capacity in place of the charge completion capacity stored in advance,
A temperature change predicting means for predicting a time change of the ambient temperature;
The remaining capacity calculation means is a discharge control device that calculates the remaining capacity corresponding to an ambient temperature in a time zone in which the secondary battery is discharged . The temperature measuring means measures the ambient temperature at a predetermined interval for a predetermined period;
The storage means further stores the ambient temperature measured during the period;
The discharge control device according to claim 1 or 6 , wherein the temperature change predicting unit predicts an ambient temperature in a time zone in which the secondary battery is discharged based on the ambient temperature stored in the storage unit. The discharge control device according to any one of claims 1 to 7 ,
A secondary battery controlled by the discharge control device and storing power supplied from an external power source,
An uninterruptible power supply that supplies power to a load using at least one of the power of the first capacity and the power of the second capacity stored in the secondary battery when the external power supply stops . The uninterruptible power supply device according to claim 8 ,
A load leveling system that supplies power to a load using only the power of the second capacity stored in the secondary battery during a load leveling operation. It further comprises power consumption measuring means for measuring the power consumption of the load,
The load leveling system according to claim 9, wherein power is supplied from the secondary battery to the load when the power consumption exceeds a predetermined power value.

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