CN103679302A - Household electric utilization optimizing method based on energy storage properties of electric automobile - Google Patents

Abstract

The invention discloses a method based on predicted electricity price and energy storage properties of an electric automobile. According to the electric utilization cost of household electric appliances, charging cost of a storage battery of the electric automobile, loss cost of the storage battery of the electric automobile and discharging benefits of the storage battery of the electric automobile, the SoC (state of charge) of the storage battery for optimizing of electric utilization cost is determined. When the electric automobile comes back, the SoC of the storage battery meets and is higher than the SoC of the storage battery for optimizing of electric utilization cost, the nonadjustable load is supplied with power, so the household electric utilization cost is reduced, and meanwhile, the load of a power grid in the peak period is reduced. Meanwhile, the new electric utilization load peak caused by a high-power charging load power supply network can be effectively avoided; according to the predicted electricity price, the adjustable load is adjusted to use in the electric utilization valley period and the electricity price valley period, the load valley is furthest filled, and the contradiction between the electric utilization requirement of the user and the greatly increased household electric utilization cost is effectively solved.

Description

A kind of household electricity optimization method based on electric automobile energy storage characteristic

Technical field

The invention belongs to power technology field, more specifically say, relate to a kind of household electricity optimization method based on electric automobile energy storage characteristic.

Background technology

Along with the development of electric automobile correlation technique, electric automobile is day by day universal.Electric automobile charges under intelligent grid environment, the duration of charging needing is longer, and because its charge power is larger, may cause electric net overload and time peak phenomenon, have a strong impact on the safety and stability of electrical network, and increase grid generation cost and user power utilization spending.

Charging electric vehicle load is compared with other household electricity loads, possesses controllability in time scale, so, in residential electric power system, discharging and recharging of electric automobile carried out to rational scheduling meeting and to user, bring income.User can control it according to the SoC state of the charge-discharge characteristic of accumulator of electric car and accumulator, realizes household electricity cost minimization.

How in the situation that meeting user power utilization demand, according to the current discharge time having carried out of accumulator, choosing accumulator is that the best SoC state of non-adjustable load supplying is that the present invention carries out electricity consumption scheduling to electric automobile and discharges and recharges the key of control.To electric automobile (V2G) technology that networks, i.e. the interaction problems research of electric automobile and supplier of electricity is more both at home and abroad, but is that the optimization solution research that discharges and recharges under residential electric power system of electric automobile is less to user's self-control electricity consumption strategy.After electric automobile is popularized in a large number, the contradiction between user's need for electricity and household electricity cost increase considerably is not reasonably solved.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, a kind of household electricity optimization method based on electric automobile energy storage characteristic is provided, reduce as much as possible household electricity cost meeting under user's need for electricity prerequisite, extend accumulator of electric car serviceable life, for the extensive electric automobile of introducing under residential electric power system discharges and recharges and lays the foundation.

For achieving the above object, the present invention is based on the household electricity optimization method of electric automobile energy storage characteristic, it is characterized in that, comprise the following steps:

(1), intelligent electric meter carries out Research on electricity price prediction in conjunction with historical electricity price data, obtains the forecasted electricity market price data on the same day;

(2), according to the electricity price design data tunable load of intelligent electric meter prediction, (tunable load is the household electrical appliance that can adjust enabling time, such as washing machine, dryer, disinfection cabinet etc.) the electricity consumption period, make it be operated in the minimum time period of electricity price in time regulatable section;

(3), according to the electricity price data of intelligent electric meter prediction, electric automobile is adjusted to the minimum period of electricity price and charges;

(4) if electric automobile uses came back constantly as electricity price peak period, the state of charge SoC of its accumulator when intelligent electric meter is come back according to electric automobile, judges whether to meet the battery charge will state SoC that electric cost is optimized ^*if meet the battery charge will state SoC optimizing higher than electric cost ^*, intelligent electric meter adjust accumulator of electric car be current be non-adjustable load (non-adjustable load is the household electrical appliance that can not adjust enabling time, such as refrigerator, illuminating lamp, kitchen electricity consumption etc.) power supply, until do not meet; If do not meet, adopting electrical network is directly non-adjustable load supplying;

Wherein, the battery charge will state that electric cost is optimized is determined according to the electric discharge income of the cost depletions of the charging cost of the electric cost of household electrical appliance, accumulator of electric car, accumulator of electric car and accumulator of electric car.

Goal of the invention of the present invention is achieved in that

The present invention is based on the household electricity optimization method of electric automobile energy storage characteristic, consider the electric discharge income of the electric cost of household electrical appliance, the cost depletions of the charging cost of electric automobile, accumulator of electric car and accumulator of electric car, determine the battery charge will state that electric cost is optimized.Household electricity cost is optimized from following two aspects and is considered.First, for the electricity consumption of tunable load and the charging of electric automobile, carry out cost optimization.Intelligent electric meter is equipped with in user's house inside, and this intelligent electric meter is predicted following electricity price on the basis of historical electricity price data, so that Spot Price reference data to be provided.And intelligent electric meter regulates the enabling time of tunable load and the duration of charging of electric automobile according to forecasted electricity market price data, thereby, minimize the electric cost of this equipment component; Secondly, for the electricity consumption of non-adjustable load, according to electric cost, the charging cost of accumulator of electric car, the electric discharge income of the cost depletions of accumulator of electric car and accumulator of electric car of household electrical appliance (comprising air-conditioning, refrigerator, TV etc.), determine the battery charge will state that electric cost is optimized.Now, the SoC state of accumulator when intelligent electric meter is come back according to electric automobile, judges whether to meet the battery charge will state that electric cost is optimized, if meet, intelligent electric meter adjust accumulator of electric car be current be non-adjustable load supplying, until do not meet; If do not meet, adopting electrical network is directly non-adjustable load supplying.

The present invention is based on the energy storage characteristic of forecasted electricity market price and electric automobile, according to the electric discharge income of the cost depletions of the charging cost of the electric cost of household electrical appliance, accumulator of electric car, accumulator of electric car and accumulator of electric car, determine the battery charge will state SoC that electric cost is optimized, when electric automobile is come back, the SoC state of its accumulator is when meeting the battery charge will state SoC optimizing higher than electric cost, non-adjustable load is powered, thereby when reducing household electricity cost, reduce electrical network at the load of peak period.Simultaneously, the new power load peak that can effectively avoid on this basis high-power charging load to bring to electrical network, and according to forecasted electricity market price, tunable load is adjusted to electricity consumption low peak period and the use of electricity price low ebb phase, fill up to greatest extent load valley, effectively solved user's need for electricity and the household electricity cost contradiction between increasing considerably.

Accompanying drawing explanation

Fig. 1 is the hardware configuration schematic diagram that the present invention is based on the household electricity optimization method application of electric automobile energy storage characteristic;

Fig. 2 is the process flow diagram that the present invention is based on the household electricity optimization method of electric automobile energy storage characteristic.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described, so that those skilled in the art understands the present invention better.Requiring particular attention is that, in the following description, when perhaps the detailed description of known function and design can desalinate main contents of the present invention, these are described in here and will be left in the basket.

In the present embodiment, as shown in Figure 1, 2, comprise the following aspects:

1, Research on electricity price prediction

In the present embodiment, described Research on electricity price prediction is according to the previous day, a few days ago with weighting parameters k corresponding to the last week of historical electricity price on the same day ₁, k ₂and k ₇, and in conjunction with these historical electricity price data of three days

with

obtain the forecasted electricity market price on the same day

wherein, h is time parameter, and take hour is unit, h=1, and 2 ... 24, d represents the same day at place.Like this, intelligent electric meter is walked power curve according to the following electricity price of forecasted electricity market price data formation.

According to following electricity price, walk power curve, the tunable load electricity consumption period is arranged in to the minimum time period of electricity price in time regulatable section.Meanwhile, according to the electricity price data of intelligent electric meter prediction, it is to charge the less period of power load that electric automobile is adjusted to the minimum period of electricity price.

2, accumulator of electric car electric cost

Because accumulator of electric car electric cost comprises the charging cost of accumulator of electric car and the cost depletions of accumulator of electric car, and this two parts cost is all relevant to accumulator of electric car state of charge SoC, so first need to obtain the state of charge SoC of accumulator of electric car when every day, electric automobile was come back, then calculate the electric cost of electric automobile according to these data.

2.1, in the present embodiment, according to open-circuit voltage and correspondence

state, draws and is expressed as follows the charging cost of accumulator of electric car:

$c_{\mathrm{chg}}=\frac{{\hat{a}}_d^h{t}_c{Q}_{\mathrm{batt}}(0.9-S\stackrel{\·}{o}C)}{{\mathrm{\η}}_{\mathrm{EVSE}}}---\left(1\right)$

Wherein, t _cfor accumulator of electric car charging duration, η _eVSEfor accumulator of electric car charge efficiency, Q _battfor accumulator of electric car charging capacity,

state of charge corresponding to each stage open-circuit voltage while charging for accumulator of electric car, its expression formula is:

$S\stackrel{\·}{o}C=\frac{V_{\mathrm{oc}}-\sqrt{{V_{\mathrm{oc}}}^2-4P_{\mathrm{batt}}{R}_{\mathrm{batt}}}}{2Q_{\mathrm{batt}}{R}_{\mathrm{batt}}}---\left(2\right)$

V _ocfor accumulator of electric car open-circuit voltage, P _battfor accumulator of electric car charge power, R _battfor accumulator of electric car resistance value.

2.2, in the present embodiment, the cost depletions of accumulator of electric car obtains according to accumulator of electric car cycle life and depth of discharge DoD.

But because obtaining of accumulator of electric car resistive film i.v. is directly perceived not, and the cost depletions of accumulator of electric car can be by being converted into accumulator of electric car discharge time by the battery discharging degree of depth (DoD) state and calculate serviceable life, and the cost depletions of accumulator of electric car is expressed as:

$c_d=\frac{c_b{Q}_{\mathrm{batt}}+c_l{t}_l}{L_c\mathrm{DoD}}---\left(3\right)$

Wherein, c _bfor accumulator replacement cost, c _lfor changing the labor cost of accumulator, t _lfor changing accumulator required working time, L _cfor the life-span (cycle index) of accumulator under depth of discharge, DoD is the battery discharging degree of depth, is also DoD=SoC-0.2.

2.3, above-mentioned explanation is visible, and accumulator of electric car electric cost is to consist of charging electric vehicle cost and accumulator cost depletions two parts, is therefore a multi-objective optimization question.For convenience's sake, we are integrated into a scalar aim parameter by linear weight α by these two optimization aim in formula (1), (3).Can draw the electric cost of accumulator of electric car thus, be expressed as follows:

$\begin{array}{c}{c}_{\mathrm{PEV}}=\mathrm{\α}\·c_{\mathrm{chg}}+(1-\mathrm{\α})\·c_d\\ =\mathrm{\α}\frac{{\hat{a}}_d^h{t}_c{Q}_{\mathrm{batt}}(0.9-S\stackrel{\·}{o}C)}{{\mathrm{\η}}_{\mathrm{EVSE}}}+(1-\mathrm{\α})\frac{c_b{Q}_{\mathrm{batt}}+c_l{t}_l}{L_c(\mathrm{SoC}-0.2)}\end{array}---\left(4\right)$

3, according to the user power utilization data and the forecasted electricity market price that record in intelligent electric meter, the electric cost of household electrical appliance can be expressed as:

$c_{\mathrm{App}}=(\mathrm{\Σ}{x}_i^{\mathrm{sl}}{t}_i^{\mathrm{sl}}+\mathrm{\Σ}{x}_i^{\mathrm{hl}}{t}_i^{\mathrm{hl}}){\hat{a}}_d^h---\left(5\right);$

Wherein,

be the use electrical power consumed of i tunable load,

be the use electrical power consumed of i non-adjustable load,

be the electricity consumption duration of i tunable load,

it is the electricity consumption duration of i non-adjustable load.

The use electrical power consumed that the electric cost that is household electrical appliance is all tunable loads and the use electrical power consumed of all non-adjustable loads and.

4, the electric discharge income of accumulator of electric car

In this embodiment, the dump energy of accumulator of electric car can be to non-adjustable load supplying, the income of bringing for user:

$g_{\mathrm{PEV}}=30I(\mathrm{SoC}-0.2)Q_{\mathrm{batt}}{\hat{a}}_d^h---\left(6\right)$

Wherein, I is battery discharging electric current.

5, according to the electric discharge income of the electric cost of accumulator of electric car electric cost, household electrical appliance, accumulator of electric car, determine objective function:

$\begin{array}{c}\mathrm{\ψ}=\underset{\mathrm{So}{C}^{*},\mathrm{\ΔSoC}}{\min }[c_{\mathrm{PEV}}+c_{\mathrm{App}}-g_{\mathrm{PEV}}]\\ =\underset{\mathrm{So}{C}^{*},\mathrm{\ΔSoC}}{\min }[\mathrm{\α}\frac{{\hat{a}}_d^h{t}_c{Q}_{\mathrm{batt}}(0.9-S\stackrel{\·}{o}C)}{{\mathrm{\η}}_{\mathrm{EVSE}}}+(1-\mathrm{\α})\frac{c_b{Q}_{\mathrm{batt}}+c_l{t}_l}{L_c({\mathrm{SoC}}_{j+1}-0.2)}\\ +(\mathrm{\Σ}{x}_i^{\mathrm{sl}}{t}_i^{\mathrm{sl}}+\mathrm{\Σ}{x}_i^{\mathrm{hl}}{t}_i^{\mathrm{hl}}){\hat{a}}_d^h-30I(\mathrm{SoC}-0.2)Q_{\mathrm{batt}}{\hat{a}}_d^h\left)\right]\end{array}---\left(7\right)$

According to objective function Ψ, determine that the battery charge will state of electric cost optimization is the electric discharge threshold value SoC of accumulator ^*and accumulator of electric car is from initial discharge time L _cto maximum discharge time L _{c_max}corresponding optimal discharge state of charge Δ SoC;

Wherein, boundary condition is $\left\{\begin{array}{c}{\mathrm{SoC}}_{\min }\≤\mathrm{SoC}\≤{\mathrm{SoC}}_{\max }\\ L_c\≤L_{c\_\max }\end{array}\right.,$

SoC wherein _minfor the lower limit of accumulator of electric car discharge charge state, SoC _maxfor the upper limit of accumulator of electric car charging charge state, L _{c_max}maximal value for accumulator of electric car its discharge time within the scope of serviceable life.

6, after user's electric automobile uses and comes back, the intelligent electric meter in connection in house.Intelligent electric meter is recorded the discharge time L of current accumulator of electric car _cwith accumulator of electric car state of charge SoC state.If electric automobile uses came back constantly as electricity price peak period, the battery charge will state SoC that the electric cost obtaining according to the objective function intelligent electric meter in formula (7) is again optimized ^*after, compare with current accumulator of electric car state of charge SoC, now whether available accumulator dump energy is non-adjustable load supplying to judge whether to meet the battery charge will state of electric cost optimization, if the battery charge will state SoC optimizing higher than electric cost ^*, intelligent electric meter adjustment accumulator of electric car is current non-adjustable load (non-adjustable load is the household electrical appliance that can not adjust enabling time, such as refrigerator, illuminating lamp, kitchen electricity consumption etc.) power supply, until do not meet; If do not meet, adopting electrical network is directly non-adjustable load supplying.If electric automobile uses, come back constantly as electricity price peak period, to adopt electrical network directly for being in harmonious proportion non-adjustable load supplying.

Example

Battery discharging number of times L c	SoC ＊	ΔSoC
			L c≤1500	SoC ＊=37%	ΔSoC=55%
1500≤L c≤2000	SoC ＊=35%	ΔSoC=65%
			2000≤L c≤2500	SoC ＊=37.5%	ΔSoC=60%
2500≤L c≤3000	SoC ＊=39%	ΔSoC=60%

Table 1

Table 1 is the battery charge will state instantiation that accumulator of electric car electric cost is optimized, and after electric automobile use is come back, intelligent electric meter is recorded the discharge time L of current accumulator of electric car _cwith accumulator of electric car state of charge SoC state, the whether current non-adjustable load of battery charge will condition selecting (non-adjustable load is the household electrical appliance that can not adjust enabling time, such as refrigerator, illuminating lamp, the kitchen electricity consumption etc.) power supply of optimizing according to the accumulator of electric car electric cost of optimizing out.

Optimization of the present invention comprises: encouraging electric automobile user in night electrical network underrun period, is also to charge in the relatively low stage of electricity price.In electrical network heavy-duty service period, by tunable load mean allocation in the low power consumption phase to guarantee network load balance movement.Reduce as much as possible household electricity cost meeting under user's need for electricity prerequisite, extend accumulator of electric car serviceable life.

Although above the illustrative embodiment of the present invention is described; so that those skilled in the art understand the present invention; but should be clear; the invention is not restricted to the scope of embodiment; to those skilled in the art; as long as various variations appended claim limit and definite the spirit and scope of the present invention in, these variations are apparent, all utilize innovation and creation that the present invention conceives all at the row of protection.

Claims (4)

1. the household electricity optimization method based on electric automobile energy storage characteristic, is characterized in that, comprises the following steps:

(1), intelligent electric meter carries out Research on electricity price prediction in conjunction with historical electricity price data, obtains the forecasted electricity market price data on the same day;

(2), according to the electricity price design data tunable load of intelligent electric meter prediction, (tunable load is the household electrical appliance that can adjust enabling time, such as washing machine, dryer, disinfection cabinet etc.) the electricity consumption period, make it be operated in the minimum time period of electricity price in time regulatable section;

(3), according to the electricity price data of intelligent electric meter prediction, electric automobile is adjusted to the minimum period of electricity price and charges;

(4) if electric automobile uses came back constantly as electricity price peak period, the state of charge SoC of its accumulator when intelligent electric meter is come back according to electric automobile, judges whether to meet the battery charge will state SoC that electric cost is optimized ^*if, meet, intelligent electric meter adjust accumulator of electric car be current be non-adjustable load (non-adjustable load is the household electrical appliance that can not adjust enabling time, such as refrigerator, illuminating lamp, kitchen electricity consumption etc.) power supply, until do not meet; If do not meet, adopting electrical network is directly non-adjustable load supplying;

Wherein, the battery charge will state that electric cost is optimized is determined according to the electric discharge income of the cost depletions of the charging cost of the electric cost of household electrical appliance, accumulator of electric car, accumulator of electric car and accumulator of electric car.

2. household electricity optimization method according to claim 1, is characterized in that, described Research on electricity price prediction is according to the previous day, a few days ago with weighting parameters k corresponding to the last week of historical electricity price on the same day ₁, k ₂and k ₇, and in conjunction with these historical electricity price data of three days

with obtain the forecasted electricity market price on the same day

wherein, h is time parameter, and take hour is unit, h=1, and 2 ... 24, d represents the same day at place.

3. household electricity optimization method according to claim 2, is characterized in that, described accumulator of electric car electric cost is:

$\begin{array}{c}{c}_{\mathrm{PEV}}=\mathrm{\α}\·c_{\mathrm{chg}}+(1-\mathrm{\α})\·c_d\\ =\mathrm{\α}\frac{{\hat{a}}_d^h{t}_c{Q}_{\mathrm{batt}}(0.9-S\stackrel{\·}{o}C)}{{\mathrm{\η}}_{\mathrm{EVSE}}}+(1-\mathrm{\α})\frac{c_b{Q}_{\mathrm{batt}}+c_l{t}_l}{L_c(\mathrm{SoC}-0.2)}\end{array}$

Wherein, c _chgfor the charging cost of accumulator of electric car, t _cfor accumulator of electric car charging duration, η _eVSEfor accumulator of electric car charge efficiency, Q _battfor accumulator of electric car charging capacity,

state of charge corresponding to each stage open-circuit voltage while charging for accumulator of electric car, its expression formula is:

$S\stackrel{\·}{o}C=\frac{V_{\mathrm{oc}}-\sqrt{{V_{\mathrm{oc}}}^2-4P_{\mathrm{batt}}{R}_{\mathrm{batt}}}}{2Q_{\mathrm{batt}}{R}_{\mathrm{batt}}}\text{;}$

V _ocfor accumulator of electric car open-circuit voltage, P _battfor accumulator of electric car charge power, R _battfor accumulator of electric car resistance value;

C _dfor the cost depletions of accumulator of electric car, c _bfor accumulator replacement cost, c _lfor changing the labor cost of accumulator, t _lfor changing accumulator required working time, L _cfor the life-span (cycle index) of accumulator under depth of discharge, DoD is the battery discharging degree of depth, is also DoD=SoC-0.2.

4. household electricity optimization method according to claim 3, it is characterized in that, the battery charge will state of described electric cost optimization is defined as according to the electric discharge income of the cost depletions of the charging cost of the electric cost of household electrical appliance, accumulator of electric car, accumulator of electric car and accumulator of electric car:

According to the electric discharge income of the electric cost of accumulator of electric car electric cost, household electrical appliance, accumulator of electric car, determine objective function:

$\begin{array}{c}\mathrm{\ψ}=\underset{\mathrm{So}{C}^{*},\mathrm{\ΔSoC}}{\min }[c_{\mathrm{PEV}}+c_{\mathrm{App}}-g_{\mathrm{PEV}}]\\ =\underset{\mathrm{So}{C}^{*},\mathrm{\ΔSoC}}{\min }[\mathrm{\α}\frac{{\hat{a}}_d^h{t}_c{Q}_{\mathrm{batt}}(0.9-S\stackrel{\·}{o}C)}{{\mathrm{\η}}_{\mathrm{EVSE}}}+(1-\mathrm{\α})\frac{c_b{Q}_{\mathrm{batt}}+c_l{t}_l}{L_c({\mathrm{SoC}}_{j+1}-0.2)}\\ +(\mathrm{\Σ}{x}_i^{\mathrm{sl}}{t}_i^{\mathrm{sl}}+\mathrm{\Σ}{x}_i^{\mathrm{hl}}{t}_i^{\mathrm{hl}}){\hat{a}}_d^h-30I(\mathrm{SoC}-0.2)Q_{\mathrm{batt}}{\hat{a}}_d^h\left)\right]\end{array}$

According to objective function Ψ, determine that the battery charge will state of electric cost optimization is the electric discharge threshold value SoC of accumulator ^*and accumulator of electric car is from initial discharge time L _cto maximum discharge time L _{c_max}corresponding optimal discharge state of charge Δ SoC;

Wherein, boundary condition is $\left\{\begin{array}{c}{\mathrm{SoC}}_{\min }\≤\mathrm{SoC}\≤{\mathrm{SoC}}_{\max }\\ L_c\≤L_{c\_\max }\end{array}\right.,$

Wherein, c _appfor the electric cost of household electrical appliance,

be the use electrical power consumed of i tunable load,

be the use electrical power consumed of i non-adjustable load,

be the electricity consumption duration of i tunable load,

it is the electricity consumption duration of i non-adjustable load;

G _pEVfor the electric discharge income of accumulator of electric car, I is battery discharging electric current.

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