U.S. patent application number 14/922139 was filed with the patent office on 2016-02-11 for charging control system and charging control method.
The applicant listed for this patent is NEC Corporation. Invention is credited to Koji Kudo, Ryosuke Kuribayashi, Hitoshi Yano.
Application Number | 20160039303 14/922139 |
Document ID | / |
Family ID | 47752630 |
Filed Date | 2016-02-11 |
United States Patent
Application |
20160039303 |
Kind Code |
A1 |
Kuribayashi; Ryosuke ; et
al. |
February 11, 2016 |
CHARGING CONTROL SYSTEM AND CHARGING CONTROL METHOD
Abstract
A charging control system that controls charging for a vehicle
that runs on electricity, including at least one rechargeable unit;
a charging unit that charges the vehicle or the rechargeable unit
with electricity; and a charging control unit that controls
charging such that when the charging time for the vehicle by the
charging unit is a predetermined time or shorter than the
predetermined time, the vehicle is charged with electricity from
the rechargeable unit.
Inventors: |
Kuribayashi; Ryosuke;
(Tokyo, JP) ; Yano; Hitoshi; (Tokyo, JP) ;
Kudo; Koji; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NEC Corporation |
Tokyo |
|
JP |
|
|
Family ID: |
47752630 |
Appl. No.: |
14/922139 |
Filed: |
October 24, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13409004 |
Feb 29, 2012 |
9168838 |
|
|
14922139 |
|
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Current U.S.
Class: |
320/109 ;
320/155 |
Current CPC
Class: |
B60L 2260/58 20130101;
B60L 2240/70 20130101; Y02T 90/14 20130101; B60L 53/11 20190201;
B60L 2240/80 20130101; Y04S 10/126 20130101; Y02T 10/72 20130101;
Y02T 90/16 20130101; Y04S 30/14 20130101; H02J 7/0027 20130101;
B60L 53/53 20190201; Y04S 30/12 20130101; B60L 2260/54 20130101;
B60L 53/64 20190201; Y02E 60/00 20130101; B60L 53/68 20190201; B60L
53/30 20190201; B60L 55/00 20190201; H02J 7/0071 20200101; Y02T
90/167 20130101; B60L 53/14 20190201; Y02T 10/70 20130101; Y02T
90/12 20130101; B60L 53/63 20190201; B60L 2260/52 20130101; B60L
53/65 20190201; Y02T 10/7072 20130101 |
International
Class: |
B60L 11/18 20060101
B60L011/18 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 1, 2011 |
JP |
2011-190656 |
Claims
1. A charging control system that controls charging for a vehicle
that runs on electricity, comprising: at least one rechargeable
means; charging means that charges said vehicle or said
rechargeable means with electricity; and charging control means
that controls charging such that when a charging time for said
vehicle by said charging means is a predetermined time or shorter
than the predetermined time, said vehicle is charged with
electricity from said rechargeable means.
2. The charging control system according to claim 1, wherein said
charging control means controls charging such that when the
charging for said vehicle by said charging means is longer than the
predetermined time, said rechargeable means is charged with
electricity by said charging means based on a state of stored
electricity of said rechargeable means.
3. The charging control system according to claim 1, further
comprising: charging scheduling means that performs scheduling in
which said charging means charges said vehicle based on an electric
power demand that causes said charging means to charge said vehicle
with electricity.
4. A charging control system that controls charging for a vehicle
that runs on electricity, comprising: at least one rechargeable
means; charging means that charges said vehicle or said
rechargeable means with electricity; charging scheduling means that
performs scheduling in which said charging means charges said
vehicle based on an electric power demand that causes said charging
means to charge said vehicle with electricity; and charging control
means that controls charging such that when a charging time for
said vehicle cannot be predicted, said vehicle is charged with
electricity from said rechargeable means.
5. A charging control method for a charging control system,
including: at least one rechargeable means; and charging means that
charges a vehicle that runs on electricity, said method comprising:
controlling charging such that when a charging time for said
vehicle by said charging means is a predetermined time or shorter
than the predetermined time, said vehicle is charged with
electricity from said rechargeable means.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Continuation Application of
U.S. patent application Ser. No. 13/409,004, filed on Feb. 29,
2012, which is based on Japanese Patent Application No. 2011-190656
filed on Sep. 1, 2011, the entire contents of which are hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a charging control system
and a charging control method that applies to vehicles that run on
electricity, the vehicles including hybrid type vehicles that are
equipped with an non-electric power source.
[0004] 2. Description of the Related Art
[0005] In that serious concern is being focused on environmental
problems in recent years, it is thought that renewable power
supplies such as photovoltaic power generator and wind power
generators that are being rapidly implemented will become effective
means to achieve low carbon society and solve energy resource
problems. On the other hand, however, since such renewable power
supplies have large output fluctuations, adjustment means need to
be provided that offsets their output fluctuations from the
standpoint of supplying quality power. To date, since thermal
generators that have high response speeds have been implemented as
the adjustment means, this results in a dilemma in which as
renewable power supplies are increasingly implemented, more thermal
power generators are needed as adjustment means. Thus, it will
become an important problem to ensure alternative powerful
adjustment means. Although it might be effective means to implement
large capacity rechargeable batteries such as NaS batteries, they
would have a very high implementation barrier from the
implementation and operation cost perspectives.
[0006] V2G (Vehicle-to-Grid) techniques that cause rechargeable
batteries equipped in vehicles, that run on electricity and that
are expected to be rapidly popularized (hereinafter, these vehicles
including hybrid type vehicles equipped with a non-electric power
source are referred to as EVs (Electric Vehicles)) and chargers
connected thereto to be linked, and to be used them as a virtual
large capacity rechargeable battery that would stabilize the power
system have been studied. V2G has been proposed since 1980s and
research including estimation of macroscopic stabilization effects
of the entire electric power grid have been continuously reported
up to the present. In recent several years, microscopic control
techniques that are used in the manufacturing of specific systems,
namely those that individually control charging and discharging of
many EVs in real time have been reported.
[0007] Examples include, Non-patent Literature 1 (G. K.
Venayagamoorthy et. al., "Real-Time Modeling of Distributed Plug-in
Vehicles for V2G Transactions," Energy Conversion Congress and
Exposition, 2009. ECCE 2009. IEEE, 3937-3941 (2009)) presents a
charging and discharging control method that performs optimum
scheduling based on Particle Swarm Optimization (PSO) that sets up
EV operation models, electric power grid models, time variation
models of electric power prices, and so forth and that was inspired
by movement of a shoal of fish.
[0008] Patent Literature 1 (JP2000-20977A, Publication) describes a
configuration of an EV charging scheduling device and also mentions
optimum charging schedule based on a genetic algorism.
[0009] Patent Literature 2 (JP2010-213560A, Publication) describes
a configuration that stably charges an EV using a stationary
rechargeable battery that serves as an electric power buffer
connected in series between the electric power grid and the EV
without necessity to expand the capacity of the electric power grid
side infrastructure.
[0010] Although a configuration that is expected not only to charge
an EV with electricity but also to discharge it from the EV to the
electric power grid side is also referred to as V2G, a
configuration that is expected only to charge the EV with
electricity might be referred to as G2V so as to distinguish itself
from V2G. G2V would reduce the load imposed on the internal
rechargeable battery provided in each EV because of a decrease in
charging and discharging cycles.
[0011] However, to date, few practical systems that comprehensive
evaluate the reduction of load and risk (imperfect charging upon
departure and accelerated deterioration of rechargeable battery of
EV) imposed on EVs' owners, the quality of grid stabilization
service, real time response, decrease of load imposed on
computational processes for optimum scheduling, and so forth have
been reported. Thus, this situation has bottlenecked the
implementation of multiple EVs linked to a charging control
system.
[0012] Next, realistic problems with respect to charging schedule
for EVs will be described.
[0013] As a first problem, if connection times at which EVs are
connected to chargers (electric power grid) at daytime at temporary
parking lots largely fluctuate and if their connection times are
unexpectedly short, the charging schedule will not be implemented
exactly as planned, and this will result in EVs that are not fully
charged. Even if arrival times and departure times of EVs can be
completely ensured, if the connection times are too short, since
the degree of freedom with respect to shifting charging times is
low, charging demands that occur in EVs would not be almost
effectively used to stabilize the electric power grid and thereby
they would be expected to simply become temporal peak noise of
electric power demands or could concentrate to a time zone in which
charge connection times are long (for example, nighttime).
[0014] As a second problem, in a transitional period of
popularization of EVs or if EV use times are irregularly patterned,
since few or no EVs are connected to chargers (electric power
grid), a time zone in which charging control can hardly be
performed, namely, power demands that serve as an electric power
adjustment capability are not supplied to the electric power supply
(electric company) side, (this time zone is referred to as a dead
time) could occur. In addition, before and after the dead time,
since the number of EVs connected to the chargers (electric power
grid) is small, it is likely that the load (rapid charging,
imperfect charging, and so forth) concentrates on particular
EVs.
[0015] FIG. 1a exemplifies a dead time that occurs in an ordinary
multiple EV linked charging system and shows charger connection
states that are generated at random for 50 EVs that are used for
commuting for three days (one holiday and two weekdays). FIG. 1b
exemplifies dead times that occur in an ordinary multiple EV linked
charging system and shows that charging scheduling is performed
such that charging demands of all EVs that arrived are adjusted in
chronological order in the time zone in which the EVs stopped.
[0016] As shown in FIG. 1a, when EVs are not connected to chargers,
they are running, namely they are consuming electric power. In FIG.
1a, the amounts of stored electricity of individual EVs at the
beginning of the first day were randomly generated.
[0017] As shown in FIG. 1b, in a time zone in which EVs are
running, namely they are not connected to chargers, dead times in
which electric power (charging) demands cannot be controlled
occur.
[0018] In the configuration described in Patent Literature 2, since
a stationery rechargeable battery is connected in series between
the electric power grid and the EV side, electric power supplied
from the electric power grid is temporarily stored in the
stationary rechargeable battery, and all EVs are charged with
electricity through the stationary rechargeable battery, it would
be necessary to provide a large capacity rechargeable battery that
satisfies charging demands of nearly all the EVs although it would
not be necessary to increase the rated capacity of an electric
power system that is superior to the stationary rechargeable
battery. Thus, it could be expected that both the initial cost and
operation cost would remarkably increase.
[0019] Since charging demands that EVs create have the potential to
prevent electric power demands from being forcibly created so as to
stabilize the electric power grid, namely to prevent energy
resources from being wasted and thereby to effectively use the
saved energy for others. Thus, the charging demands of EVs could be
considered to be a kind of "energy resources." In this context,
latent electric power demands for the electric power grid that can
chronologically shift demands to some extent are defined as
electric power charging demand potentials.
SUMMARY OF THE INVENTION
[0020] The present invention has been made in view of the problems
involved in the foregoing techniques and its object is to provide a
charging control system and a charging control method that allow
electric power demands to vary with respect to alleviation of load
and risk imposed on EVs' owners and to improving the quality of
system stabilization service.
[0021] To accomplish the foregoing object, the present invention is
a charging control system that controls charging for a vehicle that
runs on electricity, comprising:
[0022] at least one stationary rechargeable means;
[0023] charging means that charges said vehicle or said stationary
rechargeable means with electricity;
[0024] detection means that detects states of charge of said
vehicle and said stationary rechargeable means;
[0025] charging scheduling means that performs scheduling in which
said charging means charges said vehicle based on an electric power
demand that cause said charging means to charge said vehicle with
electricity; and
[0026] charging control means that controls said charging such that
when said charging of said vehicle satisfies a predetermined
condition, said vehicle is charged with electricity from said
stationary rechargeable means and when the charging of said vehicle
does not satisfy the predetermined condition, said vehicle is
charged with electricity by said charging means and said stationary
rechargeable means is charged with electricity by said charging
means based on the state of stored electricity of said stationary
rechargeable means detected by said detection means,
[0027] wherein said charging scheduling means performs charging
scheduling for said charging means that charges said vehicle and
said stationary rechargeable means with electricity also based on
an electric power demand created under the control of said charging
control means.
[0028] In addition, the present invention is a charging control
method for a charging control system, including: at least one
stationary rechargeable means; and charging means that charges a
vehicle that runs on electricity, comprising:
[0029] a charging control step that controls charging such that
when said charging of said vehicle satisfies a predetermined
condition, said vehicle is charged with electricity from said
stationary rechargeable means and when the charging of said vehicle
does not satisfy the predetermined condition, said vehicle is
charged with electricity by said charging means and said stationary
rechargeable means is charged with electricity by said charging
means based on the state of stored electricity of said stationary
rechargeable means; and
[0030] a charging scheduling step that performs charging scheduling
for said charging means that charges said vehicle with electricity
also based on an electric power demand created by said charging
means that charges said vehicle with electricity, said electric
power demand including electric power demand created by charging
performed under the control of said charging control step.
[0031] Since the present invention is configured as described
above, it allows electric power demands to vary with respect to the
alleviation of load and risk imposed on EVs' owners and to
improving of the quality of system stabilization service.
BRIEF DESCRIPTION OF THE DRAWING
[0032] FIG. 1a exemplifies a dead time that occurs in an ordinary
multiple EV linked charging system and shows charger connection
states that are generated at random for 50 EVs that are used for
commuting for three days (one holiday and two weekdays).
[0033] FIG. 1b exemplifies dead times that occur in an ordinary
multiple EV linked charging system and shows that charging
scheduling is performed such that charging demands of all EVs that
arrived are adjusted in chronological order in the time zone in
which the EVs stopped.
[0034] FIG. 2a is a schematic diagram showing an overall
configuration exemplifying a charging environment for electric
vehicles that implement a charging control system according to the
present invention.
[0035] FIG. 2b is a schematic diagram showing a configuration of
electric power aggregators shown in FIG. 2a.
[0036] FIG. 3 is a schematic diagram describing that electric power
charging demand potential is transferred in the charging
environment for electric vehicles shown in FIG. 2a and FIG. 2b.
[0037] FIG. 4 is a flow chart describing a specific example of a
charging control method for the charging control system shown in
FIG. 2a and FIG. 2b.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] Next, with reference to the accompanying drawings,
embodiments of the present invention will be described.
[0039] FIG. 2a is a schematic diagram showing an overall
configuration exemplifying a charging environment for electric
vehicles that implement a charging control system according to the
present invention. FIG. 2b is a schematic diagram showing a
configuration of electric power aggregators 3a to 3c shown in FIG.
2a.
[0040] In this example, as shown in FIG. 2a, electric power
aggregators 3a, 3b, and 3c are located at small community 7,
parking lot 8, and rapid charging stand 9, respectively, such that
electric vehicles EV 5a to 5l are charged with electricity at small
community 7, parking lot 8, and rapid charging stand 9. Electric
power aggregators 3a, 3b, and 3c are connected to electrical
substation 2 through electric power grid and information
communication grid 1 that serves as charging means and electric
power control server 2a is located in electrical substation 2. On
the other hand, HEMSs (Home Energy Management Systems) 4a to 4d are
located in small community 7 and also large capacity energy storage
6 is connected to electric power grid and information communication
grid 1. Stationary energy storages 6a to 6i that serve as means
that temporarily stores electric power charging demand potentials
are distributively located in HEMSs 4a to 4d, electric power
aggregators 3a, 3b, and 3c, large capacity energy storage 6, and
electrical substation 2. Stationary energy storages 6a to 6i are
for example rechargeable batteries located in individual users'
houses, rechargeable batteries built in or located in electric
power aggregators 3a, 3b, and 3c provided in the small community,
parking lot, and rapid charging stand, a large capacity
rechargeable battery (NaS battery or the like) located immediately
downstream of electrical substation 2 and electric power grid and
information communication grid 1.
[0041] As shown in FIG. 2b, electric power aggregators 3a, 3b, and
3c each are provided with stored electricity amount detection
section 11, connection detection section 12, connection end time
acquisition section 13, chargeable time calculation section 14,
charging scheduling section 15, electric power demand request
acquisition section 16, and charging control section 17. These
constituent sections would be implemented by programs that are
executed in electric power aggregators 3a, 3b, and 3c.
Alternatively, they can be located in HEMSs 4a to 4d or the
like.
[0042] In the charging control system that has the foregoing
configuration, if the charging time for an EV from electric power
grid and information communication grid 1 cannot be predicted or if
it is predicted that an EV cannot be charged with electricity for a
predetermined time or longer, not only will the EV be connected to
electric power grid and information communication grid 1, but it
will also be charged with electricity from stationary energy
storage 6a, 6i under the control of charging control section 17
such that electric power charging demand potential that occurs are
the EV is transferred to stationary energy storage 6a to 6i. Thus,
the electric power charging demand potential is changed to an
electric power charging demand potential that can be nearly freely
chronologically shifted and charging scheduling section 15 can
perform charging scheduling and charging control not only for
ordinary EVs that can be connected to electric power grid and
information communication grid 1 for a particular time, but also
for stationary energy storages 6a to 6i.
[0043] If it is predicted that, since the number of EVs connected
to electric power grid and information communication grid 1 is a
predetermined number and is very small, a time zone in which
charging control cannot be performed(dead time), will occur, EVs
are charged with electricity from stationary energy storages 6a to
6i and electric power charging demand potentials that occur in the
EVs are transferred to stationary energy storages 6a to 6i in a
time zone in which the number of EVs connected to electric power
grid and information communication grid 1 is large, and thus
charging control can be sufficiently performed, namely electric
power demand control can be performed and stationary energy
storages 6a to 6i are charged with electricity in the dead time,
and namely electric power demands are created under the control of
charging control section 17.
[0044] In electric power grid and information communication grid 1,
electric power aggregators 3a, 3b, and 3c are expected to be hub
type devices that bind a plurality of power wires and information
wires and are defined to include devices that have the functions of
a transformer, scheduler, or buffer.
[0045] Next, a charging control method for the charging control
system having the foregoing configuration will be described.
[0046] FIG. 3 is a schematic diagram describing that an electric
power charging demand potential is transferred in the charging
environment for electric vehicles shown in FIG. 2a and FIG. 2b.
[0047] As shown in FIG. 3, after EV 105 run, since it consumed
electric power (discharged electricity) and the amount of stored
electricity decreases, it needs to be charged with electricity.
Thus, this means that EV 105 has electric power charging demand
potential 300.
[0048] If the charging time for an EV by electric power grid and
information communication grid 101 cannot be predicted or if it is
predicted to be short, when the EV is connected to electric power
grid and information communication grid 101, stored electric energy
200 is immediately transferred from stationary energy storage 106
to EV's internal rechargeable battery 100, namely, the EV is
charged with electricity, under the control of charging control
section 17. This means that electric power charging demand
potential 300 is transferred to stationary energy storage 106. Once
electric power charging demand potential 300 is transferred to
stationary energy storage 106 that is connected to electric power
grid and information communication grid 101 for 24 hours a day, the
EV can be charged with electricity anytime, namely an electric
power demand can be created. Thus, even if the departure time of
the EV is uncertain or very soon, charging scheduling section 15
can effectively use electric power charging demand potential 300
that occurs in the EV so as to perform scheduling and thereby
stabilize the electric power grid. In addition, since it is almost
unlikely that the internal rechargeable battery of the EV has not
been fully charged when it departs, the load and risk imposed on
the EV's owner would be alleviated.
[0049] If few or no EVs are connected to electric power grid and
information communication grid 101 and thereby if it is predicted
that a time zone in which charging control cannot be performed
(dead time) occurs, the EV's internal rechargeable battery 100 will
be charged with electricity from stationary energy storage 106 that
has been fully charged in a time zone in which the number of EVs
connected to electric power grid and information communication grid
101 is large and thereby charging control can be sufficiently
performed, namely electric power demand control can be performed,
under the control of charging control section 17 such that electric
power charging demand potential 300 that occurs in the EV is
temporarily transferred to stationary energy storage 106 and
stationary energy storage 106 is charged with electricity in the
dead time, namely an electric power demand is created. Thus, dead
times in which electric power demands that charging scheduling
section 15 use to perform charging scheduling cannot be controlled
could be eliminated. As a result, before and after a dead time in
which the number of EVs connected to electric power grid and
information communication grid 101 is small, since the load can be
prevented from concentrating to a particular EV, the EV's owner can
receive the benefits.
[0050] Next, a charging control method for the foregoing charging
control system will be specifically described.
[0051] FIG. 4 is a flow chart describing a specific example of the
charging control method for the charging control system shown in
FIG. 2a and FIG. 2b.
[0052] First, past achievement data (both weekdays and holidays)
with respect to connection times, amounts of stored electricity,
and so-forth for individual electric vehicles EV 5a to 5l connected
to electric power grid and information communication grid 1 are
acquired (at step 1). Thereafter, charging demands at individual
times (both weekdays and holidays for several days after the next
day) are predicted based on the past achievement data and then the
average values (predicted values) of arrival times (charger
connection times) and departure times (charger disconnection times)
of EVs 5a to 5l are calculated (at step 2).
[0053] Along with these calculations, electric power demand request
acquisition section 16 acquires time variation data (including
electric power prices and so forth) of electric power demands
targeted for charging demand control (at step 3).
[0054] If connection detection section 12_detects that EVs 5a to 5l
is connected to electric power grid and information communication
grid 1 (at step 4), stored electricity amount detection section 11
will detect the state of stored electricity of EVs 5a to 5l and
acquire information with respect to the current amounts of stored
electricity, necessary amounts of stored electricity, and so forth
for individual EVs 5a to 5l (at step 5).
[0055] Connection end time acquisition section 13 acquires
scheduled (predicted) departure times and then chargeable time
calculation section 14 calculates chargeable times that are
continuous connection assurance times for electric power grid and
information communication grid 1 taking into account their margins
(at step 6). The scheduled departure times may be acquired from the
EV's owner side.
[0056] If it is likely that the calculated chargeable time that
exceeds a predetermined time cannot be ensured, namely that the EV
will depart in a very short time and that the EV cannot be charged
with electricity from electric power grid and information
communication grid 1 for the predetermined time or longer (at step
7), charging control section 17 will cause the EV to be immediately
charged with electricity from a stationary energy storage ES (ID
#1) that has been fully charged and electric power charging demand
potential that occurs in the EV to be transferred to the stationary
energy storage ES (ID #1) (at step 8). Stored electricity amount
detection section 11 detects whether or not the stationary energy
storage ES (ID #1) has been fully charged with electricity.
[0057] If the EV has not been fully charged with electricity (at
step 9), it will be charged with electricity from another
stationary energy storage ES (ID #2) and the EV will be
continuously charged with electricity from stationary energy
storages ESs until the EV is fully charged with electricity, namely
the electric power charging demand potential that occurs in the EV
has been transferred. Stationary energy storages ESs that have not
been fully charged with electricity are charged based on the
amounts of stored electricity of the stationary energy storages ESs
detected by stored electricity amount detection section 11 under
the control of charging control section 17.
[0058] After the degree of freedom with respect to time shift of
the electric power charging demand potential is sufficiently
increased, charging scheduling section 15 performs charging
scheduling not only for an EV group ensured that their connection
times to electric power grid and information communication grid 1
are sufficiently long, but also for a stationary energy storage ES
to which the electric power charging demand potential has been
transferred based on the electric power demands (at step 10). The
charging scheduling can be performed based on any known
algorithm.
[0059] The processes at steps 8 and 9 are not performed for the EV
group ensured that the connection times to electric power grid and
information communication grid 1 are sufficiently long.
[0060] Last, charging speeds of EVs and charging and discharging
speeds of stationary energy storages ESs acquired by the foregoing
scheduling are transferred as parameters that vary time after time
to the charging and discharging controllers provided in EV chargers
and stationary energy storages ESs and thereby electric power
demands are controlled (electricity is charged and discharged). The
total electric power demand viewed from the electric power grid
side at each time is the sum of charging demands of these EVs and
stationary energy storages ESs.
[0061] As another mode, if few or no EVs are connected to electric
power grid and information communication grid 1 and thereby if it
is predicted that a time zone in which electric power demands
cannot be controlled (dead time) occurs based on the past
achievement data and so forth, it is preferable to add a process
that causes the EV to be charged with electricity from a stationary
energy storage ES that has been fully charged with electricity and
it is preferable that an electric power charging demand potential
that occurs in the EV to be temporarily transferred to the
stationary energy storage ES (ID #1) in a time zone in which many
EVs are connected to electric power grid and information
communication grid 1 and charging control can be sufficiently
performed, namely electric power demands can be controlled to the
flow of charging control section 17. Thus, an ES to which an
electric power charging demand potential has been transferred can
be treated as an EV that has a chargeable remaining time of 24
hours and thereby an electric power demand can be created any time
for 24 hours. As a result, a controllable electric power demand can
be created in a dead time in which electric power demand cannot be
controlled, namely dead time can be eliminated.
[0062] According to the present invention, a multiple EV linked
charging system and a charging control method that have the
following two features and that allow any electric power demand to
vary can be provided.
[0063] As a first feature, even if connection times during which
EVs that are parked in the daytime at temporary parking lots are
connected to chargers or to the electric power grid largely vary
and thereby the connection times cannot be predicted or connection
times are very short, charging demand potentials that occur in the
EVs are not wasted, but are effectively used to stabilize the
electric power grid anytime for 24 hours. Thus, the quality of the
electric power grid stabilization service can be improved. In
addition, the likelihood in which EVs have not been fully charged
with electricity when they depart can be eliminated and thereby the
load and risk imposed on EVs' owners could be alleviated.
[0064] As a second feature, in a transitional period of
popularization of EVs or even if EV use times are irregularly
patterned, occurrence of a time zone in which electric power
demands cannot be scarcely controlled, namely electric power
demands cannot be provided as electric power adjustment capability
to the electric power supply (electric power company) side (dead
time) can be suppressed. Thus, the quality of the electric power
grid stabilization service can be improved. As a result, the
likelihood in which the load (rapid charging, imperfect charging,
and so forth) concentrates on a particular EV can be
eliminated.
[0065] Assuming that an EV is a simple electric power demanding
device, since a stationary rechargeable battery is located in
parallel with the demanding device in an electric power grid
downstream of a power plant and an electrical substation, it
becomes similar to the configuration of a system that is provided
with only a large capacity stationary rechargeable battery (NaS or
the like) in order to stabilize the electric power grid. However,
since the stationary rechargeable battery is used so as to support
the multiple EV linked charging system that absorbs some variations
rather to absorb all variations of electric power generations and
demands, the capacity of the stationary rechargeable battery is
very small compared to such a system. In an estimation based on a
decrease of electric power demands acquired from the simulation
result based on the occurrence of a dead time in which electric
power demands cannot be controlled as exemplified in FIG. 4b, it
can be estimated that the capacity of the stationary rechargeable
batteries is around 5% of the total capacity of internal
rechargeable batteries of all EVs. If the electric power grid were
tried to be stabilized only with stationary rechargeable batteries
rather than with the multiple EV linked charging system, stationary
rechargeable batteries for the total capacity of internal
rechargeable batteries of all the EVs would be located. Instead,
according to the present invention, the capacity of the stationary
rechargeable batteries becomes around 1/20 of that of the system
that does not use the multiple EV linked charging system.
[0066] Stationary energy storages 6a to 6i according to this
embodiment are the same as EVs 5a to 5l except that stationary
energy storages 6a to 6i are stationary, namely they are connected
to the electric power grid and information communication grid for
24 hours a day and also EVs 5a to 5l are charged with electricity
not through stationary energy storages 6a to 6i. In other words,
stationary energy storages 6a to 6i according to this embodiment
are used to increase or decrease the number of EVs from standpoint
of the electric power grid side in virtual and real time. Thus,
unlike the techniques of the related art, it is not necessary to
provide a large capacity stationary dischargeable battery, but only
stationary dischargeable batteries having a capacity of several %
to 10% of that of all EVs. In addition, since the stationary
rechargeable batteries are charged or discharged as needed,
deterioration of the rechargeable batteries will be remarkably
delayed. As a result, cost can be generally reduced.
[0067] With reference to the embodiments, the present invention was
described. However, it should be understood by those skilled in the
art that the structure and details of the present invention may be
changed in various manners without departing from the scope of the
present invention.
[0068] The present application claims priority based on Japanese
Patent Application JP 2011-190656 filed on Sep. 1, 2011, the entire
contents of which are incorporated herein by reference in its
entirety.
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