Description
POWER SUPPLY SYSTEM, AND POWER SUPPLY CONTROL METHOD AND POWER
SUPPLY CONTROL PROGRAM EMPLOYED IN POWER SUPPLY SYSTEM
Technical Field
[0001] The present invention relates to a power supply system, including an electrical storage
device which supplies power when a commercial power supply or other power supply has
stopped, to a power supply control method of the power supply system, and to a program causing
a computer to execute a power supply control method of the power supply system.
Background Art
[0002] In recent years, storage devices have attracted attention and been used as backup power
supplies for commercial power supplies. A backup power supply is charged when the
commercial power supply is operating normally, and when an abnormality in the commercial
power supply occurs, continues to supply electric power to equipment in place of the commercial
power supply. A UPS (Uninterruptible Power Supply) is one such example. By instantaneously
switching to the output from a backup power supply at the time of a power outage of the
commercial power supply, shutdown of computers and storage devices being used, servers and
other network equipment, and similar can be prevented in advance. In a backup power supply
which incorporates such storage devices, control is performed so as to maintain a state of high
remaining capacity, indicating the charged state of the electrical storage device (State of Charge,
hereafter "SOC").
[0003] An electrical storage device may for example be combined with solar cells or another
power generation device and used as a power supply system. A power generation device uses
sunlight, wind, water power, or other natural energy to generate electric power. A power supply
system which incorporates such an electrical storage device stores excess power in the electrical
storage device, and by supplying power from the electrical storage device when required by a
load device, improves energy efficiency.
[0004] A solar power generation system is an example of such a power supply system. In a solar
power generation system, when the amount of power generated from sunlight is greater than the
amount of power consumed by a load device, an electrical storage device is charged using the
excess power. Conversely, when the generated power is less than the amount of power
consumed by the load device, power discharged from the electrical storage device is supplied to
the load device in order to augment the power deficiency. In such a solar power generation
system, excess power which in the past would not have been utilized is stored in an electrical
storage device, so that compared with a conventional power supply system, energy efficiency can
be improved.
[0005] This principle is also exploited in hybrid electric vehicles (hereafter "HEVs") employing
engines and motors. In an HEV, when the output from the engine is greater than the driving
power necessary for vehicle travel, the excess power drives a generator to charge an electrical
storage device. And in the HEV, during vehicle braking and deceleration, by using the motor as
a generator, the electrical storage device is charged.
[0006] Further, load-leveling power supplies and plug-in hybrid vehicles which make effective
use of power generated at night are attracting attention. A load-leveling power supply is a system
with reduced power consumption. Power is accumulated in an electrical storage device at
nighttime, when electric power rates are inexpensive, and the accumulated power is utilized in
the daytime, when power consumption peaks. By leveling the amount of electric power
consumption, the amount of electric power generated is made constant, with the aims of
contributing to efficient utilization of electric power facilities and reduced facility investments.
[0007] On the other hand, plug-in hybrid vehicles utilize nighttime electric power. During travel
in cities, in which fuel mileage is poor, travel is primarily EV travel in which electric power is
supplied from an electrical storage device, and during long-distance travel, HEV travel utilizing
the engine and the motor is employed. An aim of plug-in hybrid vehicles is to reduce the total
amount of CO2 emissions.
[0008] Further, hybrid elevators have been developed in which, by providing a passenger
enclosure and a counterweight, the amount of power consumption required during operation is
suppressed. In such elevator systems in general, charging is controlled such that the SOC does
not increase to 100%, in order that excess electrical power due to the power generation action of
the motor efficiently charges an electrical storage device, and charging is controlled such that the
SOC does not fall to 0 (zero), in order to provide electric power to the motor when necessary.
Specifically, control is executed such that the SOC of the electrical storage device normally is
within the range from 20 % to 80%.
[0009] Such a hybrid elevator can utilize the electric power of the electrical storage device
during a power outage, so that when a power outage or other anomalous state occurs during
operation, electric power is supplied from the electrical storage device to drive the elevator, the
elevator can be operated to move to the nearest floor or to an arbitrary floor, and passengers
within the elevator enclosure can be safely rescued.
[0010] The electrical storage device mounted in a power supply system or similar as described
above includes a plurality of storage elements (single cells, unit cells, or similar) connected in
series. Hence in such a power supply system, the electrical storage device and each of the
storage elements provided in the electrical storage device is monitored at prescribed sampling
periods, and when an abnormality occurs in a storage element, power input and output to the
electrical storage device is stopped, to prevent degradation caused by overdischarge and
overcharge of the storage element.
[0011] As such a method of storage device control, for example Patent Document 1 discloses a
method of control in which the power values of a secondary battery are measured at each
prescribed period, and by judging whether an abnormality exists in the secondary battery from
the measurement results, the secondary battery is protected from overdischarge and overcharge.
[0012] However, in the control method disclosed in Patent Document 1, measurement of the
voltage and current of the secondary battery, computation of the power value of the secondary
battery based on the measurement results, and judgment of the presence of an abnormality in the
secondary battery based on the computation results, must all be executed upon each prescribed
period. Further, this processing is of course executed during normal operation of the secondary
battery, so that an extremely large burden is placed on the microcomputer which controls this
processing. For this reason, when the period in which the above processing is performed is
shortened, it becomes difficult to complete all the processing within a fixed amount of time.
[0013] In particular, in backup applications in which the supply of energy is required up until
immediately before the electrical storage device enters a dangerous state, if the state of the
electrical storage device can no longer be monitored in realtime, there is the possibility that the
electrical storage device may reach a dangerous state.
Patent Document 1: Japanese Patent Application Laid-open No. 2006-136101
[0014] In light of the above problems, an object of the invention is to provide a power supply
system, a power supply control method in a power supply system, and a power supply control
program in a power supply system, which, when a power supply has stopped due to a disaster or
for other reasons, can continue backup functions over as long a time period as possible by
reliably executing monitoring of the state of an electrical storage device.
[0015] The power supply system according to one aspect of the invention includes a power
supply which supplies power to a load device; an electrical storage device which supplies power
to the load device in place of the power supply when the power supply is stopped; and a
controller which controls the supply of power from the electrical storage device to the load
device by monitoring a state of the electrical storage device and detecting an abnormal state of
the electrical storage device; moreover, upon acquiring disaster information predicting stoppage
of the power supply, the controller shortens a monitoring period for monitoring the state of the
electrical storage device.
Disclosure of the Invention
[0016] By means of the present invention, a power supply system, a power supply control
method in a power supply system, and a power supply control program in a power supply system
can be provided which, when a power supply has stopped, can continue backup functions over as
long a time period as possible by reliably executing monitoring of the state of the electrical
storage device.
Brief Description of the Drawings
[0017] [Fig. 1] Fig. 1 is a block diagram showing the configuration of the power supply-
system of Embodiment 1 of the invention.
[Fig. 2] Fig. 2 is a block diagram showing the configuration of the first controller.
[Fig. 3] Fig. 3 is a block diagram showing the configuration of the second
controller.
[Fig. 4] Fig. 4 is a flowchart showing the order of processing of power supply
control in Embodiment 1 of the invention.
[Fig. 5] Fig. 5 is a block diagram showing the configuration of the power supply
system of Embodiment 2 of the invention.
[Fig. 6] Fig. 6 is a block diagram showing another configuration of the first
controller.
[Fig. 7] Fig. 7 is a flowchart showing the order of processing of power supply
control in Embodiment 2 of the invention.
[Fig. 8] Fig. 8 shows another arrangement of an open/close section.
[Fig. 9] Fig. 9 shows still another arrangement of an open/close section.
Best Mode for Carrying Out the Invention
[0018] Below, embodiments of the invention are explained, referring to the drawings. The same
sections are assigned the same symbols, and explanations of sections in the drawings with the
same symbols may be omitted.
[0019] (Embodiment 1)
Fig. 1 is a block diagram showing the configuration of the power supply system of
Embodiment 1 of the invention. As shown in Fig. 1, the power supply system 10 of the present
embodiment includes a power supply 100, a storage device 300, a charge/discharge control
device 400, a power supply control device 500, and a total electronic control unit (ECU) 600.
The power supply system 10 may for example be a power supply system using a power
generation device which generates electric power from natural energy, or a power supply system
including an electrical storage device utilizing nighttime electric power such as a load leveling
power supply or a plug-in hybrid vehicle, or may be a power supply system which backs up an
ordinary power supply, as in a UPS or a hybrid elevator.
[0020] The power supply 100 may for example be a commercial power supply, or may be an
electric generator employing an engine as the source of driving power, or similar. The load
device 200 includes various loads which are driven by supplied electric power.
[0021] The electrical storage device 300 accumulates excess electric power from the power
supply 100 and regenerated electric power generated by the load device 200; the accumulated
electric power is supplied to the load device 200 as necessary. The electrical storage device 300
includes N storage element blocks Bl, B2, ..., BN, connected in series. Each of the storage
element blocks Bl, B2, ..., BN includes a plurality of storage elements 301, electrically
connected in series. As the storage elements 301, for example nickel hydrogen batteries or other
alkaline storage batteries, lithium ion batteries or other organic batteries, or electrical double-
layer capacitors can be used. No limitations in particular are placed on the number N of storage
element blocks or on the number of storage elements 301. An electrical storage device 300
includes storage element blocks Bl, B2. .... BN made up of at least one storage element. Of
course, the number and connection relation thereof are not limited to those in Fig. 1, and any
combination of at least one storage element is sufficient.
[0022] The charge/discharge control device 400 controls charging and discharging of the
electrical storage device 300, is connected to each of the power supply 100, load device 200, and
storage device 300, and controls charging of the electrical storage device 300 from the power
supply 100 and discharging from the electrical storage device 300 to the load device 200. When
the consumption current of the load device 200 increases sharply, or when the power required by
the load device 200 exceeds a prescribed value, the charge/discharge control device 400
discharges the deficient amount of power from the electrical storage device 300 to the load
device 200.
[0023] Charge/discharge control by the charge/discharge control device 400 is normally
performed such that the SOC of the electrical storage device 300 is within the range of
approximately 20 % to 80%. However, in a load-leveling power supply, plug-in hybrid vehicle,
or other equipment which effectively utilizes nighttime electric power, control is executed such
that charging is performed until the SOC is 100%, and discharging is performed when energy is
required by the load device.
[0024] The power supply control device 500 controls the supply of electric power from the
electrical storage device 300 to the load device 200 when the power supply 100 has stopped.
[0025] The total ECU 600 is connected to the charge/discharge control device 400 and to the
power supply control device 500, and controls the entirety of the power supply system 10.
[0026] Next, the power supply control device 500 is described. In Fig. 1, the power supply
control device 500 includes a voltage measurement section 501, a current measurement section
502, a temperature measurement section 503, a communication section 504, a first controller 505,
a second controller 506, a first switching section 507, and a second switching section 508.
[0027] The voltage measurement section 501 measures voltage values of the electrical storage
device 300. Specifically, the voltage measurement section 501 measures, in time series with a
prescribed period, the terminal voltages V0, VI, V2, ..., VN-1, VN of the respective N storage
element blocks Bl, B2, ..., BN of the electrical storage device 300. The measured terminal
voltage for each storage element block is converted from an analog signal into a digital signal,
and the voltage data for each block and the sum total thereof are output as terminal voltage data
VD for the electrical storage device 300. Data output from the voltage measurement section 501
to the first switching section 507 is performed with a predetermined period. As a method of
measuring in time series the terminal voltage for each storage element block, for example a
flying capacitor method is known.
[0028] The current measurement section 502 measures current values of the electrical storage
device 300. Specifically, the current measurement section 502 measures, with a prescribed
period, the charge/discharge current I of the electrical storage device 300 using a current sensor
302. The measured charge/discharge current is converted from an analog signal into a digital
signal, and is output, together with a C (Charge)/D (Discharge) symbol indicating the charge
direction (+) or the discharge direction (-), as charge/discharge current data ID. Data output from
the current measurement section 502 to the first switching section 507 is, similarly to data output
from the voltage measurement section 501, output with a predetermined period. Here, the
current sensor 302 includes a resistor element, current transformer, and similar.
[0029] The temperature measurement section 503 measures the temperature of the electrical
storage device 300. Specifically, the temperature measurement section 503 uses a temperature
sensor 303 arranged within the electrical storage device 300 to measure, with a prescribed period,
the temperature within the electrical storage device 300. The measured temperature is converted
from an analog signal into a digital signal and is output, with a predetermined period, to the first
switching section 507 as temperature data TD.
[0030] The communication section 504 enables communication between the second switching
section 508 and the ECU 600. The means of communication between the ECU 600 and the
communication section 504 may be serial communication such as an ordinary RS232C interface,
or may be CAN, LIN, or Ethernet, or may be by wireless means, or similar.
[0031] The first controller 505 controls each of the sections within the power supply control
device 500. For example, the integral of the charge/discharge current data ID output from the
current measurement section 502 is computed over a prescribed time interval (for example, a
time interval of one day or less), to compute an integrated capacity Q. When performing this
integration, if the sign C/D received together with the charge/discharge current data ID indicates
the charging direction (+), the charge/discharge current data ID is multiplied by the charging
efficiency (a coefficient smaller than 1, for example 0.8). The first controller 505 uses the
integrated capacity Q to predict and store the remaining capacity SOC.
[0032] Here, the SOC was determined using the integrated capacity Q as described above, but
the present embodiment is not limited to such a configuration. For example, a plurality of data
pairs of voltage data VD and current data ID can be acquired in the charge direction (+) and in
the discharge direction (-), the no-load voltage Vo which is the voltage intercept when these data
pairs are approximated by a straight line (VD-ID straight line) can be determined, and the
electromotive force Vemf, obtained as the difference between the no-load voltage Vo and the
voltage drop due to internal resistance and the polarization component of the electrical storage
device 300, can be used as an index to reference an electromotive force-SOC characteristic table
prepared in advance through experiments to determine the SOC. Further, in applications in
which the temperature of the electrical storage device 300 fluctuates greatly, temperature data TD
output from the temperature measurement section 503 can be used as a correction parameter for
the above-described electromotive force-SOC characteristic table.
[0033] As explained below, the second controller 506 only performs, from among the processing
executed by the first controller 505, detection of an abnormal state of the electrical storage device
300 when the power supply 100 is stopped and charge/discharge management of the electrical
storage device 300 based thereupon. The second controller 506 is a controller which is
specialized for execution of this processing, and by limiting the processing content thereof, the
processing performance relative to the first controller 505 can be greatly improved.
[0034] The first switching section 507 takes as inputs the terminal voltage data VD from the
voltage measurement section 501, the charge/discharge current data ID from the current
measurement section 502, and the temperature data TD from the temperature measurement
section 503, and outputs these data items to one among the first controller 505 and the second
controller 506. The first switching section 507 is controlled by the first controller 505, and the
output destination of the first switching section 507 is decided based on an instruction from the
first controller 505.
[0035] The second switching section 508 enables communication between the total ECU 600
and one among the first controller 505 and the second controller 506, using the communication
section 504. The second switching section 508 is controlled by the first controller 505, and the
connecting end of the first switching section 507 is decided based on an instruction from the first
controller 505.
[0036] Next, processing of power supply control by the power supply control device 500 is
explained. The power supply control device 500 monitors the state of the electrical storage
device 300 when supplying power from the electrical storage device 300 to the load device 200
while the power supply 100 is stopped, and maintains the power supply capability of the
electrical storage device 300. Below, this processing for power supply control is explained in
detail. Initially, the configuration of the first controller 505 and second controller 506 is
explained using Fig. 2 and Fig. 3, and then the procedure of processing for power supply control
is explained.
[0037] First, as explained above, the first controller 505 controls internal sections of the power
supply control device 500, and for example is configured as follows in order to execute the
above-described processing for power supply control.
[0038] Fig. 2 shows a configuration to be provided in the first controller 505, in order to realize
the processing for power supply control of the power supply control device 500. In Fig. 2, the
first controller 505 includes a first abnormality detection section 5051, first charge/discharge
management section 5052, information acquisition section 5053, and switching execution section
5054.
[0039] The first abnormality detection section 5051 monitors the stales of the storage element
blocks B1, B2, ..., BN of the electrical storage device 300 with a prescribed period, and detects
an abnormal state of the electrical storage device 300. The first abnormality detection section
5051 acquires as appropriate, via the first switching section 507, the voltage data VD,
charge/discharge current data ID, and temperature data TD output from the voltage measurement
section 501, current measurement section 502 and temperature measurement section 503,
performs various computations based on these data items VD, ID and TD, and detects an
abnormal state of the electrical storage device 300. For example, if the voltage value of the
electrical storage device 300 is equal to or less than a prescribed voltage value in a prescribed
time interval, the first abnormality detection section 5051 determines that an overdischarge state
exists in the electrical storage device 300, and detects an abnormal state of the electrical storage
device 300.
[0040] The first charge/discharge management section 5052 sets a target value for a state
quantity of the electrical storage device 300 (hereafter called a "target state quantity"), which is
used in charge/discharge control of the electrical storage device 300 by the charge/discharge
control device 400. The charge/discharge control device 400 controls charge/discharge of the
electrical storage device 300 based on this target state quantity. The state quantity of the
electrical storage device 300 may for example be the SOC, indicating the charged state of the
electrical storage device 300; the first charge/discharge management section 5052 reverts this
target state quantity as necessary. The target state quantity which has thus been set is output to
the charge/discharge control device 400 via the second switching section 508. communication
section 504, and total ECU 600.
[0041] The information acquisition section 5053 monitors input of stoppage information for the
power supply 100 to the first controller 505, and acquires the stoppage information. Stoppage
information for the power supply 100 is taken to indicate stoppage of, for example, a commercial
power supply, main power supply, or similar. Such information may also include disaster
information indicating the possibility of stoppage of a commercial power supply. Disaster
information may be meteorological information predicting flood damage, conflagration
information, or earthquake information. Of course, such information is not limited to the above
examples, and may be any information on stoppage of the power supply 100, or disaster
information predicting such stoppage.
[0042] The switching execution section 5054 controls the first switching section 507 and second
switching section 508. The switching execution section 5054, by controlling the first switching
section 507, inputs to either the first controller 505 or the second controller 506, the voltage data
VD, charge/discharge current data ID, and temperature data TD output from the voltage
measurement section 501, the current measurement section 502, and the temperature
measurement section 503. The switching execution section 5054, by controlling the second
switching section 508, enables communication of either the first controller 505 or the second
controller 506 with the total ECU 600 using the communication section 504.
[0043] Next, Fig. 3 shows the structure to be provided by the second controller 506, in order to
realize the processing for power supply control of the power supply control device 500. In Fig. 3
the second controller 506 includes a second abnormality detection section 5061 and a second
charge/discharge management section 5062.
[0044] The second abnormality detection section 5061, similarly to the above-described first
abnormality detection section 5051, monitors the states of the storage element blocks B1, B2, ...,
BN of the electrical storage device 300 with a prescribed period, and detects an abnormal state of
the electrical storage device 300. The second abnormality detection section 5061 acquires as
appropriate, via the first switching section 507, voltage data VD, charge/discharge current data
ID, and temperature data TD output from the voltage measurement section 501, the current
measurement section 502 and the temperature measurement section 503; performs various
computations based on these data items VD, ID and TD; and detects an abnormal state of the
electrical storage device 300. For example, if the voltage value of the electrical storage device
300 is equal to or less than a prescribed voltage value in a prescribed time interval, the second
abnormality detection section 5061 determines that an overdischarge state exists in the electrical
storage device 300, and detects an abnormal state of the electrical storage device 300.
[0045] Here, a difference between the second abnormality detection section 5061 and the first
abnormality detection section 5051 is the fact that the period of state monitoring of the electrical
storage device 300 by the second abnormality detection section 5061 is set to be shorter than that
for the first abnormality detection section 5051. As explained above, the second controller 506
only performs detection of an abnormal state of the electrical storage device 300 when the power
supply 100 is stopped and charge/discharge management of the electrical storage device 300
based thereupon, and compared with the first controller 505, the processing performance for this
processing is greatly improved. Hence the second abnormality detection section 5061 can
monitor in realtime the state of the electrical storage device 300 with a period shorter than that of
the first abnormality detection section 5051. Consequently when the power supply 100 is
stopped, the supply of power from the electrical storage device 300 can be continued until
immediately before the electrical storage device 300 enters a dangerous state. For example, state
monitoring of the electrical storage device 300 by the first abnormality detection section 5051 is
executed with a period of 100 ms, and state monitoring of the electrical storage device 300 by the
second abnormality detection section 5061 is executed with a period of 50 ms.
[0046] The second charge/discharge management section 5062, similarly to the above-described
first charge/discharge management section 5052, sets a target state quantity for the electrical
storage device 300, which is used in charge/discharge control of the electrical storage device 300
by the charge/discharge control device 400. The charge/discharge control device 400 controls
charge/discharge of the electrical storage device 300 based on this target state quantity. The state
quantity of the electrical storage device 300 may for example be the SOC, indicating the charged
state of the electrical storage device 300; the second charge/discharge management section 5062
reverts this target state quantity as necessary.
[0047] Next, the procedure of processing for this power supply control is explained using Fig. 4.
Fig. 4 is a flowchart showing the procedure of processing for power supply control of the power
supply control device 500 in the present embodiment.f
[0048] As shown in Fig. 4, the information acquisition section 5053 monitors the input to the
first controller 505 of stoppage information for the power supply 100, and acquires the stoppage
information (step S101). Here, stoppage information for the power supply 100 is collected by the
total ECU 600, and is output to the power supply control device 500. The total ECU 600
internally includes an information collection section 601 to collect stoppage information for the
power supply 100, and stoppage information from outside for the power supply 100 is collected
using the information collection section 601. Stoppage information for the power supply 100
may for example be information relating to stoppage of the power supply 100 due to
meteorological conditions, conflagrations, earthquakes, or other disasters; this information is
collected by the information collection section 601. The information collection section 601 may
also directly detect stoppage of the supply of power by the power supply 100.
[0049] When stoppage information for the power supply 100 is acquired by the information
acquisition section 5053, the switching execution section 5054, by controlling the first switching
section 507, inputs to the second controller 506 the voltage data VD, charge/discharge current
data ID, and temperature data TD output from the voltage measurement section 501, current
measurement section 502 and temperature measurement section 503. Further, the switching
execution section 5054, by controlling the second switching section 508, enables communication
between the total ECU 600 and the second controller 506 using the communication section 504
(step S102). That is, upon acquiring stoppage information for the power supply 100, the first
controller 505 uses the switching execution section 5054 to control the first and second switching
sections 507 and 508, so as to cause the second controller 506 to execute the abnormal state
detection of the electrical storage device 300 and the charge/discharge mafnagement of the
electrical storage device 300 based thereupon which had been executed theretofore by the first
controller 505. Hence when the power supply 100 stops, and a backup function by the electrical
storage device 300 is executed, monitoring of the state of the electrical storage device 300 can be
executed reliably with a shorter period than during normal operation of the power supply 100,
and without detracting from realtime properties.
[0050] The second abnormality detection section 5061 of the second controller 506 begins state
monitoring of the electrical storage device 300 in place of the first abnormality detection section
5051 of the first controller 505 (step S103). The second abnormality detection section 5061
monitors the state of the electrical storage device 300 with a prescribed period, and in addition,
upon detection of an abnormal state of the electrical storage device 300 (YES in step S103), the
second controller 506 uses the communication section 504 to notify the total ECU 600 of the
abnormal state of the electrical storage device 300 (step S105).
[0051] On the other hand, so long as no anomalous state of the electrical storage device 300 is
detected in step S103 above (NO in step S103), monitoring of the state of the electrical storage
device 300 in the above step S103 is continued until the power supply 100 is reverted (YES in
step S104).
[0052] Upon receiving notification of the abnormal state of the electrical storage device 300
from the power supply control device 500, the total ECU 600 controls the charge/discharge
control device 400 to cause charge/discharge of the electrical storage device 300 to be stopped
(step S106).
[0053] In this way, processing for power supply control in Embodiment 1 of the invention is
executed.
[0054] As explained above, by means of Embodiment 1 of the invention, when the power supply
100 is stopped, the period for monitoring of the state of the electrical storage device 300 is made
shorter than during normal operation of the power supply 100, so that an abnormal state of the
electrical storage device 300 can be detected promptly and reliably, the electrical storage device
300 can be stopped, and the electrical storage device 300 can be protected. Hence even when the
supply of power is required up until immediately before the electrical storage device 300 enters a
dangerous state, the backup function of the electrical storage device 300 can be continued over as
long a time period as possible, without the electrical storage device 300 reaching a dangerous
state.
[0055] In Embodiment 1 of the invention, the details of the stopped state of the power supply
100 may be ascertained based on stoppage information for the power supply 100 acquired by the
first charge/discharge management section 5052 through the information acquisition section
5053 in step S101 of Fig. 4, and the target state quantity of the electrical storage device 300 may
be reset according to these details. By temporarily reducing the target state quantity of the
electrical storage device 300, the power supply capacity of the electrical storage device 300 can
be increased. Hence if for example stoppage of the power supply 100 is prolonged, by increasing
the power supply capacity of the electrical storage device 300, the power required by the load
device 200 can be supplied continuously over a still longer time period.
[0056] In step S105 of Fig. 4, the second charge/discharge management section 5062 may
ascertain the details of an abnormal state of the electrical storage device 300 detected by the
second abnormality detection section 5061, and may reset the target state quantity of the
electrical storage device 300 according to the details. In this case also, by temporarily reducing
the target state quantity of the electrical storage device 300, the power supply capacity of the
electrical storage device 300 can be increased. By this means, the period of state monitoring of
the electrical storage device 300 is shortened and anomalies are detected early, and the charged
state of the electrical storage device 300 is limited to a safe range according to the abnormal state
of the electrical storage device 300, so that the maximum amount of energy can be supplied in
times of disaster, while securing the safety of the electrical storage device 300.
[0057] In any of the above-described cases, temporary overdischarge of the electrical storage
device 300 occurs, but so long as overdischarge occurs in a range in which the battery
characteristics, lifetime, and reliability of the electrical storage device 300 are not compromised,
there is no effect on the battery characteristics or similar of the electrical storage device 300.
[0058] Further, when the target state quantity to be used as a target value when charging the
electrical storage device 300 is a first target state quantity, and the target state quantity to be used
as a target value when discharging the electrical storage device 300 is a second target state
quantity, by having the first charge/discharge management section 5052 raise the first target state
quantity and lower the second target state quantity when disaster information is acquired, the
capacity of power supply to the load device 200 by the electrical storage device 300 may be
increased.
[0059] For example, when the range SOC > 100% is the overcharge region and the range SOC <
0% is the overdischarge region, if during normal operation the first target state quantity is set to
SOC = 80% and the second target state quantity is set to SOC = 20%, then upon acquisition of
disaster information, the first target state quantity may be reset to SOC = 100% and the second
target state quantity may be reset to SOC = 0%.
[0060] Further, in Embodiment 1 of the invention, by for example greatly improving the
processing capability of the first controller, the first controller 505 and the second controller 506
can be integrated. In this case, the first and second switching sections 507 and 508 become
unnecessary, the number of components of the power supply control device 500 can be reduced,
and the cost of the power supply system 10 can be lowered. A controller which integrates the
first controller 505 and the second controller 506, upon acquiring stoppage information for the
power supply 100, executes state monitoring of the electrical storage device 300 with a period
shorter than during normal operation of the power supply 100. Further, a configuration may be
employed in which, when stoppage of the power supply 100 has been resolved, the period of
state monitoring of the electrical storage device 300 is returned to the normal period.
[0061] Further, in Embodiment 1 of the invention, a program to realize the processing of power
supply control of the power supply management device 500 may be executed on a
microcomputer. That is. a power supply control program to realize the first abnormality
detection section 5051, first charge/discharge management section 5052, information acquisition
section 5053, and switching execution section 5054 provided in the first controller 505 shown in
Fig. 2, as well as the second abnormality detection section 5061 and second charge/discharge
management section 5062 provided in the second controller 506 shown in Fig. 3, may be
installed on a microcomputer, and this power supply control program may be executed on the
microcomputer.
[0062] By causing a microcomputer to read and execute this power supply control program, the
power supply control method of the power supply control device 500 is realized. This power
supply control program may be installed in a storage section of the microcomputer, and the
power supply control program may be executed by the central processing unit (CPU) of the
microcomputer. By using the CPU of the microcomputer to execute the power supply control
program, the first abnormality detection section 5051, first charge/discharge management section
5052, information acquisition section 5053, switching execution section 5054, second
abnormality detection section 5061, and second charge/discharge management section 5062, are
realized.
[0063] Further, in Embodiment 1 of the invention, the charge/discharge control device 400 can
be endowed with functions of the first controller 505 and second controller 506. In this case, for
example the above-described power supply control program may be installed in a microcomputer
provided in the charge/discharge control device 400, and this program may be executed. Of
course, functions of the charge/discharge control device 400 may be provided in the first
controller 505 or in the second controller 506. Further, the load device 200 or the total ECU 600
may be endowed with functions of the first and second controllers 505 and 506. For example,
when the total ECU 600 includes functions of the first and second controllers 505 and 506, the
power supply control device 500 has only limited functions, such as functions for measuring the
voltage, temperature, and current of the electrical storage device 300. Further, a power supply of
the present invention may be a network-type power supply comprising an information
transmission/reception section.
[0064] (Embodiment 2)
Next, Embodiment 2 of the invention is explained. The above-described Embodiment 1
related to a power supply system in which, when stoppage information for the power supply 100
is acquired, monitoring of the state of the electrical storage device is executed reliably by
shortening the period of state monitoring of the electrical storage device 300, and the backup
function is continued over as long a time period as possible. On the other hand, in the present
embodiment, when stoppage information for the power supply 100 has been acquired, by forcibly
detaching the electrical storage device 300 from the charge/discharge control device 400 after a
prescribed time has elapsed, the safety of the electrical storage device 300 and power supply
system 10 is reliably secured.
[0065] Fig. 5 is a block diagram showing the configuration of the power supply system of
Embodiment 2 of the invention. As shown in Fig. 5, the power supply system 10 of the present
embodiment, similarly to the above-described Embodiment 1, includes a power supply 100, a
storage device 300, a charge/discharge control device 400, a power supply control device 500,
and a total electronic control unit (ECU) 600. The power supply system 10 of the present
embodiment differs from the above Embodiment 1 in that the power supply control device 500
includes a first controller 505a in place of the first controller 505, and in that an open/close
section 700 is positioned on the path connecting the electrical storage device 300 and the
charge/discharge control device 400. These differences are explained below.
[0066] Fig. 6 shows a configuration to be provided in the first controller 505a, in order to realize
the processing for power supply control of the power supply control device 500 of the present
embodiment. In Fig. 6, the first controller 505a. similarly to the first controller 505 of
Embodiment 1 above, includes a first abnormality detection section 5051, first charge/discharge
management section 5052, information acquisition section 5053, and switching execution section
5054, and further includes an open/close execution section 5055.
[0067] Upon acquisition of presentation information for the power supply 100 by the information
acquisition section 5053, the open/close execution section 5055 measures the time elapsed from
the time of the acquisition, and after a predetermined prescribed time has elapsed, uses the
communication section 504 to notify the total ECU 600 of the fact that the prescribed time has
elapsed. At this time of this notification, the first controller 505a controls the second switching
section 508 using the switching execution section 5054, and secures communication with the
total ECU 600. The prescribed time may be decided in advance according to the power required
by the load device 200 connected to the power supply system 10. Of course, the time length may
also be determined according to the time period over which the power supply 100 is stopped.
[0068] Next, Fig. 7 is used to explain a procedure of processing for power supply control in the
present embodiment. Fig. 7 is a flowchart showing the procedure of processing for power supply
control in the embodiment.
[0069] As shown in Fig. 7, the information acquisition section 5053 monitors the input to the
first controller 505 of stoppage information for the power supply 100, and acquires such stoppage
information (step S201). When stoppage information for the power supply 100 is acquired by
the information acquisition section 5053, similarly to the above-described Embodiment 1, the
switching execution section 5054 controls the first switching section 507 to input to the second
controller 506 the voltage data VD, charge/discharge current data ID, and temperature data TD
output from the voltage measurement section 501, the current measurement section 502, and the
temperature measurement section 503. And the switching execution section 5054 controls the
second switching section 508 to enable communication between the total ECU 600 and the
second controller 506 using the communication section 504 (step S203). Thereafter, processing
proceeds to step SI03 in Fig. 4.
[0070] Further, when in the present embodiment stoppage information for the power supply 100
is acquired by the information acquisition section 5053 (step S201), the open/close execution
section 5055 begins measurement of the time elapsed from the time of acquisition (step S202).
And, after a predetermined time has elapsed (YES in step S204), the open/close execution
section 5055 uses the second switching section 508 and the communication section 504 to notify
the total ECU 600 that the prescribed time has elapsed (step S206). Upon receiving the
notification from the power supply control device 500, the total ECU 600 controls the open/close
section 700 to detach the electrical storage device 300 from the charge/discharge control device
400.
[0071 ] On the other hand, in the above step S204, so long as the prescribed time has not elapsed
(NO in step S204), the monitoring over the prescribed time in the above step S204 is continued
until the power supply 100 is reverted (YES in step S205).
[0072] In this way, processing for power supply control in Embodiment 2 of the present
invention is executed.
[0073] As explained above, by means of Embodiment 2 of the invention, when the power supply
100 is stopped, by putting the open/close section 700 into the open state after a prescribed
quantity of power has been supplied to the load device 200, the electrical storage device 300 can
reliably be prevented from falling into an overdischarge or other dangerous state, and the safety
of the electrical storage device 300 and of the power supply system 10 itself can be secured.
Hence the safety of the power supply system 10 can be secured while operating the load device
200 for as long as possible.
[0074] As shown in Fig. 8, in Embodiment 2 of the invention an open/close section 700a may be
positioned on the path connecting the charge/discharge control device 400 and the load device
200. As shown in Fig. 9, an open/close section 700b may be positioned on the path connecting
the charge/discharge control device 400 and the power supply 100. In these cases, even when the
electrical storage device 300 has reached a dangerous state, the safety of the power supply 100
and load device 200 can be secured.
[0075] Further, when stoppage of the power supply 100 has been resolved, the total ECU 600
may control the open/close section 700 so as to again connect the electrical storage device 300
and the charge/discharge control device 400.
[0076] Further, in step S204 of Fig. 7, when an abnormality of the electrical storage device 300
is detected by the second controller 506 even after the prescribed time has elapsed, the
open/close section 700 may detach the electrical storage device 300 from the charge/discharge
control device 400.
[0077] Further, in Embodiment 2 of the invention, a program to realize the processing of power
supply control of the power supply management device 500 may be executed on a
microcomputer. That is, a power supply control program to realize the first abnormality
detection section 5051, first charge/discharge management section 5052, information acquisition
section 5053, switching execution section 5054, and open/close execution section 5055 provided
in the first controller 505 shown in Fig. 6, as well as the second abnormality detection section
5061 and second charge/discharge management section 5062 provided in the second controller
506 shown in Fig. 3, may be installed on a microcomputer, and this power supply control
program may be executed on the microcomputer.
[0078] By causing a microcomputer to read and execute this power supply control program, the
power supply control method of the power supply control device 500 is realized. This power
supply control program may be installed in a storage section of the microcomputer, and the
power supply control program may be executed by the central processing unit (CPU) of the
microcomputer. By using the CPU of the microcomputer to execute the power supply control
program, the first abnormality detection section 5051, first charge/discharge management section
5052, information acquisition section 5053, switching execution section 5054, open/close
execution section 5055, second abnormality detection section 5061, and second charge/discharge
management section 5062. are realized.
[0079] The invention may be summarized using each of the above embodiments as follows. A
power supply system of the invention includes a power supply which supplies electric power to a
load device; an electrical storage device which, during stoppage of the power supply, supplies
electric power to the load device in place of the power supply; and a controller which controls the
supply of power from the electrical storage device to the load device by monitoring a state of the
electrical storage device and detecting an abnormal state of the electrical storage device; upon
acquiring disaster information predicting stoppage of the power supply, the control device
shortens a monitoring period for monitoring the state of the electrical storage device.
[0080] By means of a power supply system of the present invention, when stoppage of the power
supply is predicted, by shortening the monitoring period for monitoring the state of the electrical
storage device, an abnormal state of the electrical storage device can reliably be detected even
when the electrical storage device enters a dangerous state due to supply of power to the load
device. Hence the supply of electric power by the electrical storage device to the load device can
be continued for as long as possible, without the electrical storage device reaching a dangerous
state.
• [0081] Upon detecting an abnormal state of the electrical storage device, it is preferable that the
controller reduce a power charging the electrical storage device from the power supply and a
power discharging from the electrical storage device lo the load device, to keep the input/output
power of the electrical storage device within a prescribed range, thereby controlling the supply of
power from the electrical storage device to the load device.
[0082] In this case, even when the electrical storage device is in an abnormal state, by reducing
the charging power input to the electrical storage device and the discharging power output from
the electrical storage device, the power input to and output from the electrical storage device is
limited to within a prescribed range. As a result, the electrical storage device can be prevented
from reaching a dangerous state due to an increase in the input/output power of the electrical
storage device.
[0083] In the above power supply system, it is preferable that the controller have an information
acquisition section which acquires the disaster information, and a first abnormality detection
section which monitors the state of the electrical storage device with the monitoring period and
detects an abnormal state of the electrical storage device, and that a first period be set as the
monitoring period during normal operation of the power supply, and that a second period shorter
than the first period be set as the monitoring period upon acquisition of the disaster information.
[0084] In this case, disaster information is acquired by the information acquisition section, so the
monitoring periods can be shortened according to predictions of stoppage of the power supply.
[0085] In the above power supply system, it is preferable that the controller further include a
charge/discharge management section which sets a first target state quantity indicating a charged
state of the electrical storage device to be taken as a target value when charging the electrical
storage device, and a second target state quantity indicating a charged state of the electrical
storage device to be taken as a target value when discharging the electrical storage device, in
order to maintain a charged state of the electrical storage device in a prescribed range, and that
when disaster information is acquired, the first target state quantity is raised and the second target
state quantity is lowered, to increase a capacity of power supply to the load device by the
electrical storage device.
[0086] In this case, by raising the first target state quantity and lowering the second target state
quantity of the electrical storage device when stoppage of the power supply is predicted, the
quantity of power supplied to the load device can be temporarily increased during a disaster.
[0087] In the above power supply system, it is preferable that the controller further include a
second abnormality detection section which, at the time of acquisition of disaster information,
executes monitoring of the state of the electrical storage device and detection of an abnormal
state of the electrical storage device, and that the first abnormality detection section execute
monitoring of the state of the electrical storage device and detection of an abnormal state of the
electrical storage device during normal operation of the electrical storage device.
[0088] In this case, by separately providing a second abnormality detection section which
executes only state monitoring of the electrical storage device and detection of an abnormal state
of the electrical storage device when stoppage of the power supply is predicted, this processing
can be reliably completed even with a second monitoring period which is shorter than the first
monitoring period.
[0089] In the above power supply system, it is preferable that the power supply system further
comprise an open/close section which can disconnect the electrical connection between the
electrical storage device and the power supply system, and that the controller further include an
open/close execution section which causes execution of disconnection of the electrical
connection between the electrical storage device and the power supply system by the open/close
section after a prescribed time has elapsed upon acquisition of disaster information.
[0090] In this case, after a prescribed quantity of electric power has been supplied to the load
device, the electrical storage device is electrically detached from the power supply system, so that
the electrical storage device can be reliably prevented from falling into an overdischarge or other
dangerous state, and the safety of the electrical storage device and of the power supply system
itself can be secured.
[0091] A power supply control method of a power supply system of the present invention is a
power supply control method of a power supply system that has an electrical storage device
which, at the time of stoppage of a power supply for supplying electric power to a load device,
supplies power to the load device in place of the power supply, and that controls the supply of
power from the electrical storage device to the load device by monitoring a state of the electrical
storage device and detecting an abnormal state of the electrical storage device, and the method
includes a step of monitoring the state of the electrical storage device with a first monitoring
period to monitor the state of the electrical storage device, and detecting an abnormal state of the
electrical storage device during normal operation of the power supply, and a step of monitoring
the state of the electrical storage device with a second monitoring period shorter than the first
monitoring period, and detecting an abnormal state of the electrical storage device upon
acquisition of disaster information predicting stoppage of the power supply.
[0092] According to the power supply control method of a power supply system of the present
invention, when stoppage of a power supply is predicted, by shortening the monitoring period for
monitoring the state of an electrical storage device, an abnormal state of the electrical storage
device can be promptly detected, even when the electrical storage device has entered a dangerous
state due to the supply of power to a load device. Hence the supply of electric power by the
electrical storage device to the load device can be continued for as long as possible, without the
electrical storage device reaching a dangerous state.
[0093] A power supply control program of a power supply system of the present invention is a
power supply control program of a power supply system that has an electrical storage device
which, at the time of stoppage of a power supply for supplying electric power to a load device,
supplies power to the load device in place of the power supply, and that controls the supply of
power from the electrical storage device to the load device by monitoring a state of the electrical
storage device and detecting an abnormal state of the electrical storage device, and the program
causes a computer to function as an information acquisition section which acquires disaster
information predicting stoppage of the power supply, and as an abnormality detection section
which monitors the state of the electrical storage device with a monitoring period for monitoring
the state of the electrical storage device, and detects an abnormal state of the electrical storage
device; and the abnormality detection section performs monitoring with a first monitoring period
during normal operation of the power supply, and performs monitoring with a second monitoring
period shorter than the first monitoring period when disaster information is acquired.
[0094] According to the power supply control program of a power supply system of the present
invention, when stoppage of the power supply is predicted, an abnormal state of the electrical
storage device can be promptly detected, even when the electrical storage device has entered a
dangerous state due to the supply of power to a load device. Hence the supply of electric power
by the electrical storage device to the load device can be continued for as long as possible,
without the electrical storage device reaching a dangerous state.
[0095] The embodiments of the invention disclosed above are illustrative, and do not limit the
invention. The scope of the invention is not limited to the details disclosed, but is described by
the scope of claims, and should be understood as including concepts equivalent to the claims and
all modifications within the scope of claims.
Industrial Applicability
[0096] A power supply system, and a power supply control method and power supply control
program of a power supply system of the present invention, are advantageous for use in power
supplies and equipment having backup power supply functions, and can be applied in industry.
What is claimed is:
1. A power supply system, comprising:
a power supply which supplies electric power to a load device;
an electrical storage device which, during stoppage of said power supply, supplies electric
power to said load device in place of said power supply; and
a controller which controls the supply of power from said electrical storage device to said
load device by monitoring a state of said electrical storage device and detecting an abnormal state
of said electrical storage device;
and characterized in that
upon acquiring disaster information predicting stoppage of said power supply, said
control device shortens a monitoring period for monitoring the state of said electrical storage
device.
2. The power supply system according to Claim 1, characterized in that, upon
detecting an abnormal state of said electrical storage device, said controller reduces a power
charging said electrical storage device from said power supply and a power discharging from said
electrical storage device to said load device, to keep the input/output power of said electrical
storage device within a prescribed range, thereby controlling the supply of power from said
electrical storage device to said load device.
3. The power supply system according to Claim 1, characterized in that said
controller comprises an information acquisition section which acquires the disaster information,
and a first abnormality detection section which monitors the state of said electrical storage device
with the monitoring period and detects an abnormal state of said electrical storage device, and in
that a first period is set as said monitoring period during normal operation of said power supply,
and a second period shorter than said first period is set as said monitoring period upon
acquisition of said disaster information.
4. The power supply system according to Claim 3, characterized in that said
controller further comprises a charge/discharge management section which, in order to maintain
a charged state of said electrical storage device in a prescribed range, sets a first target state
quantity indicating a charged state of said electrical storage device to be taken as a target value
when charging said electrical storage device, and a second target state quantity indicating a
charged state of the electrical storage device to be taken as a target value when discharging said
electrical storage device, and in that, when said disaster information is acquired, said first target
state quantity is raised and said second target state quantity is lowered, to increase a capacity of
power supply to said load device by said electrical storage device.
5. The power supply system according to Claim 3, characterized in that said
controller further comprises a second abnormality detection section which, at the time of
acquisition of said disaster information, executes monitoring of the state of said electrical storage
device and detection of an abnormal state of said electrical storage device, and in that said first
abnormality detection section executes monitoring of the state of said electrical storage device
and detection of an abnormal state of said electrical storage device during normal operation of
said electrical storage device.
6. The power supply system according to Claim 3 or Claim 4, characterized in that
said power supply system further comprises an open/close section which can disconnect the
electrical connection between said electrical storage device and said power supply system, and in
that said controller further comprises an open/close execution section which causes execution of
disconnection of the electrical connection between said electrical storage device and said power
supply system by said open/close section after a prescribed time has elapsed upon acquisition of
said disaster information.
7. A power supply control method of a power supply system that has an electrical
storage device which, at the time of stoppage of a power supply for supplying electric power to a
load device, supplies power to said load device in place of said power supply, and that controls
the supply of power from said electrical storage device to said load device by monitoring a state
of said electrical storage device and detecting an abnormal state of said electrical storage device,
the method comprising the steps of:
monitoring the state of said electrical storage device with a first monitoring period to
monitor the state of said electrical storage device, and detecting an abnormal state of said
electrical storage device during normal operation of said power supply; and
monitoring the state of said electrical storage device with a second monitoring period
shorter than said first monitoring period, and detecting an abnormal state of said electrical
storage device upon acquisition of disaster information predicting stoppage of said power supply.
8. A power supply control program of a power supply system that has an electrical
storage device which, at the time of stoppage of a power supply for supplying electric power to a
load device, supplies power to said load device in place of said power supply, and that controls
the supply of power from said electrical storage device to said load device by monitoring a state
of said electrical storage device and detecting an abnormal state of said electrical storage device,
the program causing a computer to function as:
an information acquisition section which acquires disaster information predicting
stoppage of said power supply; and
an abnormality detection section which monitors the state of said electrical storage device
with a monitoring period for monitoring the state of the electrical storage device, and detects an
abnormal state of said electrical storage device, and characterized in that
said abnormality detection section performs monitoring with a first monitoring period
during normal operation of said power supply, and performs monitoring with a second
monitoring period shorter than said first monitoring period when said disaster information is acquired.

A power supply system (10) is provided with a power supply device (100) for supplying a load device (200) with
power; an electrical storage device (300) for supplying the load device (200) with power by replacing the power supply device (100)
when the power supply device (100) is stopped; and a power supply control device (500) which controls power supply from the
electrical storage device (300) to the load device (200) by monitoring the status of the electrical storage device (300) and detecting
an abnormal status of the electrical storage device (300). The power supply control device (500) shortens a monitoring cycle for
monitoring the status of the electrical storage device (300) when disaster information, from which stopping of the power supply
device (100) can be predicted, is acquired, and surely monitors the status of the electrical storage device (300) when the power
supply device (100) is stopped. Therefore, a backup function is continuously operated as long as possible.