CN105356459A - A control method for allowing electric automobiles to participate in power system frequency modulation in a scattered grid-access manner - Google Patents

Abstract

Translated fromChinese

本发明公开了一种电动汽车分散入网参与电力系统调频的控制方法，主要包括以下步骤：(1)V2G控制中心查询该区域参与调频的V2G数量、SOC以及功率限额等信息；(2)调度中心获取各V2G控制中心上报可参与调频容量；(3)V2G控制中心获取调度中心下发的功率命令P_r；(4)根据用户的用车需求，选择相应的V2G参与调频控制方法，如果用户有随时取车的需求且满0.6<SOC<0.8这一条件，该类电动汽车进行“随调”模式；如果用户有不用车的固定时段且满足0.3<SOC<0.8这一条件，该类电动汽车进行“固调”模式，否则不参与调频；(5)V2G根据相应模式参与调频；(6)检测系统频率，如果系统频率恢复，则退出调频；否则重复上述步骤，直至系统频率恢复。

The invention discloses a control method for decentralized network access of electric vehicles to participate in power system frequency regulation, which mainly includes the following steps: (1) V2G control center inquires information such as the number of V2Gs participating in frequency regulation in this area, SOC and power limit; (2) dispatching center Obtain the frequency modulation capacity reported by each V2G control center; (3) The V2G control center obtains the power command P_r issued by the dispatching center; (4) According to the user's vehicle demand, select the corresponding V2G participation frequency modulation control method, if the user has If the demand for picking up the car at any time meets the condition of 0.6<SOC<0.8, this type of electric vehicle will be in the "on-demand"mode; if the user has a fixed period of time without the car and meets the condition of 0.3<SOC<0.8, this type of electric vehicle Perform "Fixed Tuning" mode, otherwise it will not participate in frequency modulation; (5) V2G participates in frequency modulation according to the corresponding mode; (6) Detect system frequency, if the system frequency recovers, exit frequency modulation; otherwise repeat the above steps until the system frequency recovers.

Description

A kind of electric automobile dispersion networks and participates in the control method of electric power system frequency modulation

Technical field

The present invention relates to a kind of electric automobile dispersion networking and participate in electric power system frequency modulation method, belong to electric vehicle engineering field.

Background technology

Energy crisis and environmental pollution have impelled the fast development of electric automobile industry, the popularization day by day of electric automobile, also for the development of electrical network provides new opportunity.Can realize the acquisition of the flow of power between electrical network and electric automobile particularly by electric automobile-electrical network interaction technique (VehicletoGrid, V2G), electric automobile can provide some assistant service abilities for electrical network.Wherein, frequency modulation is considered to the service of the potential and practicality of most.

Consider that electric automobile is as the vehicles, the demand of user is primary goal.Participate in, in system frequency modulation, often all seldom considering the user demand of electric automobile user at existing electric automobile, mostly concentrate the primary frequency modulation considering electric power system, or only consider centralized V2G mode.The present invention proposes the electric automobile power distribution strategies that the power division of control centre and V2G control centre and V2G control centre and each disperse to access.On this basis, consider the demand of electrical network, EV and user three aspect, proposing a kind of electric automobile adopts dispersion access module to participate in the control strategy of system frequency modulation, for the driving arrangement of different users, propose corresponding participation frequency modulation control method: " with tune " pattern and " Gu tune " pattern.

Summary of the invention

The invention provides the dispersion of a kind of electric automobile to network and participate in electric power system frequency modulation method, this method give V2G control centre and each disperses the power distribution strategies of the electric automobile accessed.On this basis, based on the driving arrangement of user, propose two kinds of hopping pattern.

Put forward the methods of the present invention, comprises following steps:

Step 1), the information such as V2G quantity, state-of-charge SOC and the power allowances participating in frequency modulation are inquired about by V2G control centre;

Step 2), control centre obtains participated in the frequency regulation capacity S that V2G control centre reports_i;

Step 3), the capacity that control centre reports according to V2G control centre, frequency modulation power P_totalpro rata distribution, then each V2G control centre obtains the power command P that control centre issues_r;

$P_r=P_{total}*\frac{S_i}{{\mathrm{\&Sigma;S}}_i}$

Step 4), V2G control centre uses car demand according to user, selects corresponding V2G to participate in frequency modulation control method.If user has the demand and full this condition of 0.6<SOC<0.8 of picking up the car at any time, such electric automobile carries out step 5 " with tune " pattern; If user has the fixing period without car and meet this condition of 0.3<SOC<0.8, such electric automobile carries out step 6 " Gu tune " pattern, otherwise does not participate in frequency modulation;

Step 5), pattern that V2G terminal adopts " with tune ", V2G participates in primary frequency modulation.After getting mains frequency skew, formulate electric automobile charge-discharge electric power P according to droop control principle_i,k

P_i,k＝K*Δf

If the then discharge and recharge P of electric automobile_i,kbe greater than maximum charge-discharge electric power, then make P_i,kafter=maximum charge-discharge electric power, then export P_i,k; Otherwise, directly export P_i,k;

Step 6), pattern that V2G terminal adopts " Gu tune ", according to SOC value, control V2G switches between primary frequency modulation and frequency modulation frequency modulation;

Step 6.1), if SOC is in [0.6,0.8] this interval, this electric automobile participates in frequency modulation frequency modulation, carry out step 6.2; Otherwise this electric automobile participates in primary frequency modulation, carry out step 6.4;

Step 6.2), V2G control centre distributes frequency modulation frequency modulation power P to electric automobile in proportion_{2, i};

Step 6.2.1), the P issued according to control centre_r, calculate each automobile charge-discharge electric power P_i;

As the P that control centre issues_rduring for charge power, the charge power P of each V2G_ifor:

P_i＝P_r(1-SOC_i)/∑(1-SOC_i)

When the Pr issued when control centre is discharge power, the discharge power P of each V2G_ifor:

$P_i=P_r({\mathrm{SOC}}_i-{\mathrm{SOC}}_i^{\min })/\mathrm{\&Sigma;}({\mathrm{SOC}}_i-{\mathrm{SOC}}_i^{\min })$

Step 6.2.2), by each automobile charge-discharge electric power P_icompare with maximum charge-discharge electric power, if out-of-limit, then make P_i=maximum charge-discharge electric power, gets rid of this numbering, by P simultaneously in N_sumaccumulative automobile reaches the power total value of maximum charge-discharge electric power;

Step 6.2.3), according to formula P_r=P_r-P_sum, obtain new P_r;

Step 6.2.4), the P newly obtained_rin new N, circulate above-mentioned process, until distributed to V2G to greatest extent;

Step 6.2.5), to each automobile transmit power command;

Step 6.3), if the frequency modulation frequency modulation power P of electric automobile_{2, i}be greater than maximum charge-discharge electric power, make P_{2, i}after=maximum charge-discharge electric power, export frequency modulation frequency modulation power P_{2, i}; Otherwise, directly export P_{2, i};

Step 6.4), first after getting mains frequency skew, formulate electric automobile charge/discharge power P according to droop control principle_i,k, wherein sagging coefficient gets maximum; Then the charge power P of electric automobile is calculated_i^c, according to above-mentioned result of calculation, obtain the primary frequency modulation power P of electric automobile_{1, i}

P_1,i＝P_i,k+P_i^c

If the primary frequency modulation P of electric automobile_{1, i}be greater than maximum charge-discharge electric power, make P_{1, i}after=maximum charge-discharge electric power, export primary frequency modulation power P_{1, i}; Otherwise, directly export P_{1, i};

Step 6.5), the SOC information of inquiry electric automobile, if electric automobile is in the process participating in frequency modulation frequency modulation, SOC value <0.6, is now switched to primary frequency modulation pattern; If electric automobile is in the process participating in primary frequency modulation, SOC value >0.6, is now switched to frequency modulation frequency modulation pattern;

Step 7), detection system frequency detection system frequency, if system frequency is recovered, then exits frequency modulation; Otherwise repetition above-mentioned steps, until system frequency is recovered.

Further, the present invention, with in mode transfer formula, can be described as in the frequency droop control structure maintaining battery charge state: droop control device offsets according to mains frequency, formulates electric automobile charge/discharge power.The control method of described droop control device is as follows:

Work as SOC_i^min≤ SOC_i,k≤ SOC_iⁱⁿ,time:

$\left\{\begin{array}{c}{K}_{i,k}^c=\frac{1}{2}{K}_{max}(1+a)\\ K_{i,k}^d=\frac{1}{2}{K}_{max}(1-a)\end{array}\right.$

Work as SOC_iⁱⁿ≤ SOC_i,k≤ SOC_i^max,time:

$\left\{\begin{array}{c}{K}_{i,k}^c=\frac{1}{2}{K}_{max}(1+b)\\ K_{i,k}^d=\frac{1}{2}{K}_{max}(1-b)\end{array}\right.$

Work as SOC_i,k≤ SOC_i^mintime:

$\left\{\begin{array}{c}{K}_{i,k}^c=K_{max}\\ K_{i,k}^d=0\end{array}\right.$

Work as SOC_i,k≤ SOC_i^maxtime:

$\left\{\begin{array}{c}{K}_{i,k}^c=0\\ K_{i,k}^d=K_{max}\end{array}\right.$

In above-mentioned formula, SOC_i,kfor the state-of-charge of k moment i-th batteries of electric automobile; SOC_i^minbe that i-th electric automobile allows minimum state-of-charge; SOC_i^maxbe that i-th electric automobile allows maximum state-of-charge; SOC_iⁱⁿit is the initial state-of-charge of i-th electric automobile; K_maxfor the sagging coefficient of maximum charge/discharge; K^c_i,kbe i-th electric automobile, charge sagging coefficient in the k moment; K^d_i,kbe i-th electric automobile, discharge sagging coefficient in the k moment.

Compared with prior art, tool has the following advantages in the present invention:

1. for there is the reliability of signal and the containing problem of cost of investment these two aspects in current frequency signal obtain manner, this clearly demarcated concept proposing V2G control centre.By electric automobile subregion, accepted the instruction of higher level's scheduling by the V2G control centre in each region, while ensure that frequency signal obtains reliability, decrease cost of investment to a certain extent.

2. the present invention proposes a kind of V2G control centre to each electric automobile frequency modulation power distribution strategies.According to pro rata distribution method, give each electric motor car in this region by frequency modulation power division, participate in the frequency modulation amount of frequency modulation as electric automobile.

3. the present invention is with the demand of user for primary goal, proposes two kinds of patterns that electric automobile participates in frequency modulation: " with tune " pattern and " Gu mode transfer formula ".When user needs to take electric automobile at any time, " with tune " pattern can be selected, control electric automobile and only participate in primary frequency modulation; When user within the fixing period without driving demand time, can select " solid adjust " pattern, and according to the SOC value of electric automobile, control electric automobile switches once charging between frequency modulation and frequency modulation frequency modulation.

Accompanying drawing explanation

Fig. 1 V2G participates in the main flow of electric power system frequency modulation

Fig. 2 V2G participates in power grid frequency modulation equivalent schematic

Fig. 3 V2G control centre power division flow chart

Fig. 4 participates in the main flow of primary frequency modulation with V2G under mode transfer formula

Under the solid mode transfer formula of Fig. 5, V2G participates in a frequency modulation frequency modulation flow process

Embodiment

With reference to shown in Fig. 1, the invention provides the control method that a kind of electric automobile dispersion networking participates in electric power system frequency modulation, wherein V2G control centre and the communication signal direction between control centre and V2G as shown in Figure 2, specifically comprise following steps:

Step 1), the information such as V2G quantity, SOC and the power allowances participating in frequency modulation are inquired about by V2G control centre;

Step 2), control centre obtains participated in the frequency regulation capacity S that V2G control centre reports_i;

Step 3), the capacity that control centre reports according to V2G control centre, frequency modulation power P_totalpro rata distribution, then each V2G control centre obtains the power command P that control centre issues_r;

$P_r=P_{total}*\frac{S_i}{{\mathrm{\&Sigma;S}}_i}$

Step 4), V2G control centre uses car demand according to user, selects corresponding V2G to participate in frequency modulation control method.If user has the demand and full this condition of 0.6<SOC<0.8 of picking up the car at any time, such electric automobile carries out step 5 " with tune " pattern; If user has the fixing period without car and full this condition of 0.3<SOC<0.8, such electric automobile carries out step 6 " Gu tune " pattern; Otherwise do not participate in frequency modulation;

Step 5), pattern that V2G terminal adopts " with tune ", participate in primary frequency modulation, as shown in Figure 4, step is as follows;

Step 5.1), obtain frequency fluctuation signal delta f;

Step 5.2), according to SOC initial value, calculate droop control COEFFICIENT K;

Step 5.3), according to the result of calculation of step 4.2, determine the discharge and recharge P of electric automobile_i,k;

P_i,k＝K*Δf

Step 5.4), if the discharge and recharge P of electric automobile_i,kbe greater than maximum charge-discharge electric power, make P_i,kafter=maximum charge-discharge electric power, then export P_i,k; Otherwise, directly export P_i,k;

Step 6), pattern that V2G terminal adopts " Gu tune ", according to SOC value, control V2G switches between primary frequency modulation and frequency modulation frequency modulation, and as shown in Figure 5, step is as follows;

Step 6.1), if SOC is in [0.6,0.8] this interval, this electric automobile participates in frequency modulation frequency modulation, carry out step 6.2; Otherwise this electric automobile participates in primary frequency modulation, carry out step 6.4;

Step 6.2), V2G control centre distributes frequency modulation frequency modulation power P to electric automobile in proportion_{2, i}, as shown in Figure 3;

Step 6.2.1), the P issued according to control centre_r, calculate each automobile charge-discharge electric power P_i;

As the P that control centre issues_rduring for charge power, the charge power P of each V2G_ifor:

P_i＝P_r(1-SOC_i)/∑(1-SOC_i)

When the Pr issued when control centre is discharge power, the discharge power P of each V2G_ifor:

$P_i=P_r({\mathrm{SOC}}_i-{\mathrm{SOC}}_i^{\min })/\mathrm{\&Sigma;}({\mathrm{SOC}}_i-{\mathrm{SOC}}_i^{\min })$

Step 6.2.2), by each automobile charge-discharge electric power P_icompare with maximum charge-discharge electric power, if out-of-limit, then make P_i=maximum charge-discharge electric power, gets rid of this numbering, by P simultaneously in N_sumaccumulative automobile reaches the power total value of maximum charge-discharge electric power;

Step 6.2.3), according to formula P_r=P_r-P_sum, obtain new P_r;

Step 6.2.4), the P newly obtained_rin new N, circulate above-mentioned process, until distributed to V2G to greatest extent;

Step 6.2.5), to each automobile transmit power command;

Step 6.3), if the frequency modulation frequency modulation power P of electric automobile_{2, i}be greater than maximum charge-discharge electric power, make P_{2, i}after=maximum charge-discharge electric power, export frequency modulation frequency modulation power P_{2, i}; Otherwise, directly export P_{2, i};

Step 6.4), V2G participates in primary frequency modulation;

Step 6.4.1), obtain frequency fluctuation signal delta f;

Step 6.4.2), sagging coefficient gets maximum, calculates the discharge and recharge P of electric automobile_i,k;

P_i,k＝K_max*Δf

Step 6.4.3), calculate the charge power P of electric automobile_i^c;

$P_i^c=({\mathrm{SOC}}_i^e-{\mathrm{SOC}}_i^{now})*E_i^r/(t_i^{out}-t_i^{now})$

Step 6.4.4), according to the result of calculation of step 6.4.3 and step 6.4.4, calculate the primary frequency modulation power P of electric automobile_{1, i}

P_1,i＝P_i,k+P_i^c

Step 6.4.5) if the primary frequency modulation power P of electric automobile_{1, i}be greater than maximum charge-discharge electric power, make P_{1, i}after=maximum charge-discharge electric power, export primary frequency modulation power P_{1, i}; Otherwise, directly export P_{1, i};

Step 6.5), the SOC information of inquiry electric automobile, if electric automobile is in the process participating in frequency modulation frequency modulation, SOC value <0.6, is now switched to primary frequency modulation pattern; If electric automobile is in the process participating in primary frequency modulation, SOC value >0.6, is now switched to frequency modulation frequency modulation pattern;

Step 7), detection system frequency detection system frequency, if system frequency is recovered, then exits frequency modulation; Otherwise repetition above-mentioned steps, until system frequency is recovered.

Because user needs to take automobile at any time, " with tune " pattern that the present invention proposes, idiographic flow as shown in Figure 4, wherein sagging COEFFICIENT K and SOC physical relationship as follows:

Work as SOC_i^min≤ SOC_i,k≤ SOC_iⁱⁿ,time:

$\left\{\begin{array}{c}{K}_{i,k}^c=\frac{1}{2}{K}_{max}(1+a)\\ K_{i,k}^d=\frac{1}{2}{K}_{max}(1-a)\end{array}\right.$

Work as SOC_iⁱⁿ≤ SOC_i,k≤ SOC_i^max,time:

$\left\{\begin{array}{c}{K}_{i,k}^c=\frac{1}{2}{K}_{max}(1+b)\\ K_{i,k}^d=\frac{1}{2}{K}_{max}(1-b)\end{array}\right.$

Work as SOC_i,k≤ SOC_i^mintime:

$\left\{\begin{array}{c}{K}_{i,k}^c=K_{max}\\ K_{i,k}^d=0\end{array}\right.$

Work as SOC_i,k≤ SOC_i^maxtime:

$\left\{\begin{array}{c}{K}_{i,k}^c=0\\ K_{i,k}^d=K_{max}\end{array}\right.$

In above-mentioned formula, SOC_i,kfor the state-of-charge of k moment i-th batteries of electric automobile; SOC_i^minbe that i-th electric automobile allows minimum state-of-charge; SOC_i^maxbe that i-th electric automobile allows maximum state-of-charge; SOC_iⁱⁿit is the initial state-of-charge of i-th electric automobile; K_maxfor the sagging coefficient of maximum charge/discharge; K^c_i,kbe i-th electric automobile, charge sagging coefficient in the k moment; K^d_i,kbe i-th electric automobile, discharge sagging coefficient in the k moment.

Claims (3)

Translated fromChinese

1.一种电动汽车分散入网参与电力系统调频的控制方法，其特征在于，该方法包括如下步骤：1. A control method for electric vehicle decentralized network access to participate in power system frequency modulation, characterized in that the method may further comprise the steps:步骤1)，V2G控制中心查询参与调频的V2G数量、SOC以及功率限额等信息；Step 1), the V2G control center queries information such as the number of V2G participating in frequency modulation, SOC and power limit;步骤2)，调度中心获取V2G控制中心上报的可参与调频容量S_i；Step 2), the dispatching center obtains the participating frequency modulation capacity S_i reported by the V2G control center;步骤3)，调度中心根据V2G控制中心上报的容量，把调频功率P_total按比例分摊，然后各V2G控制中心获取调度中心下发的功率命令P_r；Step 3), the dispatching center apportions the frequency modulation power P_total according to the capacity reported by the V2G control center, and then each V2G control center obtains the power command P_r issued by the dispatching center;${\mathrm{<span><span>P</span>P</span>}}_{\mathrm{<span><span>r</span>r</span>}}<span><span>=</span>=</span>{\mathrm{<span><span>P</span>P</span>}}_{\mathrm{<span><span>t</span>t</span>}\mathrm{<span><span>o</span>o</span>}\mathrm{<span><span>t</span>t</span>}\mathrm{<span><span>a</span>a</span>}\mathrm{<span><span>l</span>l</span>}}<span><span>*</span>*</span>\frac{{\mathrm{<span><span>S</span>S</span>}}_{\mathrm{<span><span>i</span>i</span>}}}{{\mathrm{<span><span>\&Sigma;S</span>\&Sigma;S</span>}}_{\mathrm{<span><span>i</span>i</span>}}}$步骤4)，V2G控制中心根据用户的用车需求，选择相应的V2G参与调频控制：如果用户有随时取车的需求且满0.6<SOC<0.8这一条件，该类电动汽车进行步骤5“随调”模式；如果用户有不用车的固定时段且满足0.3<SOC<0.8这一条件，该类电动汽车进行步骤6“固调”模式，否则不参与调频；Step 4), the V2G control center selects the corresponding V2G to participate in the frequency modulation control according to the user's car needs: if the user has the demand to pick up the car at any time and meets the condition of 0.6<SOC<0.8, this type of electric car will go to step 5 "follow If the user has a fixed period of time without the car and meets the condition of 0.3<SOC<0.8, this type of electric vehicle will go to step 6 "fixed tuning" mode, otherwise it will not participate in frequency regulation;步骤5)，V2G终端采用“随调”模式，V2G参与一次调频。在获取到电网频率偏移后，根据下垂控制原理制定电动汽车充放电功率P_i,kIn step 5), the V2G terminal adopts the "on-the-fly" mode, and the V2G participates in a frequency modulation. After obtaining the grid frequency offset, formulate the electric vehicle charging and discharging power P_i,k according to the droop control principleP_i,k＝K*ΔfP_i,k = K*Δf如果电动汽车的充放电功率P_i,k大于最大充放电功率，则令P_i,k＝最大充放电功率后，再输出P_i,k；否则，直接输出P_i,k；If the charging and discharging power P_i,k of the electric vehicle is greater than the maximum charging and discharging power, set P_i,k = the maximum charging and discharging power, and then output P_i,k ; otherwise, directly output P_i,k ;步骤6)，V2G终端采用“固调”模式，根据SOC值，控制V2G在一次调频和二次调频之间切换；Step 6), the V2G terminal adopts the "fixed tuning" mode, and controls the V2G to switch between primary frequency modulation and secondary frequency modulation according to the SOC value;步骤6.1)，如果SOC在[0.6,0.8]这一区间，该电动汽车参与二次调频，进行步骤6.2；否则，该电动汽车参与一次调频，进行步骤6.4；Step 6.1), if the SOC is in the interval [0.6,0.8], the electric vehicle participates in the second frequency regulation, proceed to step 6.2; otherwise, the electric vehicle participates in the primary frequency regulation, proceed to step 6.4;步骤6.2)，V2G控制中心按比例给电动汽车分配二次调频功率P_2,i；Step 6.2), the V2G control center distributes the secondary frequency modulation power P_2,i to the electric vehicle in proportion;步骤6.2.1)，按照调度中心发布的P_r，计算每辆汽车充放电功率P_i；Step 6.2.1), calculate the charging and discharging power P_i of each vehicle according to the P_r issued by the dispatching center;当调度中心发布的P_r为充电功率时，每辆V2G的充电功率P_i为：When the P_r issued by the dispatch center is the charging power, the charging power P_i of each V2G vehicle is:P_i＝P_r(1-SOC_i)/∑(1-SOC_i)P_i =P_r (1-SOC_i )/∑(1-SOC_i )当调度中心发布的Pr为放电功率时，每辆V2G的放电功率P_i为：When the Pr issued by the dispatch center is the discharge power, the discharge power Pi of each_V2G vehicle is:${\mathrm{<span><span>P</span>P</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>=</span>=</span>{\mathrm{<span><span>P</span>P</span>}}_{\mathrm{<span><span>r</span>r</span>}}<span><span>(</span>(</span>{\mathrm{<span><span>SOC</span>SOC</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>SOC</span>SOC</span>}}_{\mathrm{<span><span>i</span>i</span>}}^{\mathrm{<span><span>min</span>min</span>}}<span><span>)</span>)</span><span><span>/</span>/</span>\mathrm{<span><span>\&Sigma;</span>\&Sigma;</span>}<span><span>(</span>(</span>{\mathrm{<span><span>SOC</span>SOC</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>SOC</span>SOC</span>}}_{\mathrm{<span><span>i</span>i</span>}}^{\mathrm{<span><span>min</span>min</span>}}<span><span>)</span>)</span>$步骤6.2.2)，将每辆汽车充放电功率P_i与最大充放电功率进行比较，如果越限，则令P_i＝最大充放电功率，同时在N中排除该编号，由P_sum累计汽车达到最大充放电功率的功率总额；Step 6.2.2), compare the charging and discharging power P_i of each vehicle with the maximum charging and discharging power, if it exceeds the limit, set P_i = the maximum charging and discharging power, and exclude this number in N at the same time, and accumulate the vehicle by P_sum The total amount of power to reach the maximum charging and discharging power;步骤6.2.3)，根据公式P_r＝P_r-P_sum，获得新的P_r；In step 6.2.3), a new P_r is obtained according to the formula P_r =P_r -P_sum ;步骤6.2.4)，新得到的P_r在新的N中，循环上述的过程，直到被最大限度的分配给V2G；Step 6.2.4), the newly obtained P_r is in the new N, and the above-mentioned process is cycled until it is allocated to V2G to the maximum;步骤6.2.5)，给每辆汽车发送功率指令；Step 6.2.5), send power command to each car;步骤6.3)，如果电动汽车的二次调频功率P_2,i大于最大充放电功率，令P_2,i＝最大充放电功率后，再输出二次调频功率P_2,i；否则，直接输出P_2,i；Step 6.3), if the secondary frequency modulation power P_2,i of the electric vehicle is greater than the maximum charge and discharge power, set P_2,i = maximum charge and discharge power, then output the secondary frequency modulation power P_2,i ; otherwise, directly output P_2,i ;步骤6.4)，首先在获取到电网频率偏移后，根据下垂控制原理制定电动汽车充放电功率P_i,k，其中下垂系数取最大值，然后计算电动汽车的充电功率P_i^c，根据上述计算结果，得到电动汽车的一次调频功率P_1,iStep 6.4), first, after obtaining the frequency offset of the grid, formulate the electric vehicle charging and discharging power P_i,k according to the droop control principle, where the droop coefficient takes the maximum value, and then calculate the charging power P_i^c of the electric vehicle, according to the above calculation As a result, the primary frequency modulation power P_1,i of the electric vehicle is obtainedP_1,i＝P_i,k+P_i^cP_1,i =P_i,k +P_i^c如果电动汽车的一次调频功率P_1,i大于最大充放电功率，令P_1,i＝最大充放电功率后，再输出一次调频功率P_1,i；否则，直接输出P_1,i；If the primary frequency modulation power P_1,i of the electric vehicle is greater than the maximum charging and discharging power, set P_1,i = the maximum charging and discharging power, and then output the frequency modulation power P_1,i again; otherwise, directly output P_1,i ;步骤6.5)，查询电动汽车的SOC信息，如果电动汽车在参与二次调频的过程中，SOC值<0.6，此时切换到一次调频模式；如果电动汽车在参与一次调频的过程中，SOC值>0.6，此时切换到二次调频模式；Step 6.5), query the SOC information of the electric vehicle, if the electric vehicle is participating in the process of secondary frequency regulation, the SOC value is <0.6, then switch to the primary frequency regulation mode; if the electric vehicle is participating in the process of primary frequency regulation, the SOC value> 0.6, switch to secondary frequency modulation mode at this time;步骤7)，检测系统频率，如果系统频率恢复，则退出调频；否则重复上述步骤，直至系统频率恢复。Step 7), detect the system frequency, if the system frequency recovers, exit the frequency modulation; otherwise, repeat the above steps until the system frequency recovers.2.根据权利要求1所述的一种电动汽车分散入网参与电力系统调频的控制方法，其特征在于，所述V2G控制中心为：将电动汽车分成多个区域，每个区域内设有一个V2G控制中心，由所述V2G控制中心接受电力调度中心的调频任务，然后将有功调节任务按比例分配到所辖范围内的电动汽车。2. A control method for decentralized network access of electric vehicles to participate in power system frequency modulation according to claim 1, wherein the V2G control center is: divide electric vehicles into multiple areas, and each area is provided with a V2G The control center, the V2G control center accepts the frequency regulation task of the power dispatching center, and then distributes the active power regulation task in proportion to the electric vehicles within its jurisdiction.3.根据权利要求1所述的一种电动汽车分散入网参与电力系统调频的控制方法，其特征在于，所述随调模式下下垂控制方法具体为：3. A control method for decentralized network access of electric vehicles to participate in power system frequency modulation according to claim 1, characterized in that, the droop control method in the follow-up mode is specifically:当SOC_i^min≤SOC_i,k≤SOC_iⁱⁿ，$a=\sqrt{\frac{{\mathrm{SOC}}_{i,k}-{\mathrm{SOC}}_i^{\mathrm{in}}}{{\mathrm{SOC}}_i^{\min }-{\mathrm{SOC}}_i^{\mathrm{in}}}}$时：When SOC_i^min ≤SOC_i,k ≤SOC_iⁱⁿ ,$a=\sqrt{\frac{{\mathrm{SOC}}_{i,k}-{\mathrm{SOC}}_i^{\mathrm{in}}}{{\mathrm{SOC}}_i^{\min }-{\mathrm{SOC}}_i^{\mathrm{in}}}}$ Time:$\left\{\begin{array}{c}{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>i</span>i</span>}<span><span>,</span>,</span>\mathrm{<span><span>k</span>k</span>}}^{\mathrm{<span><span>c</span>c</span>}}<span><span>=</span>=</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>m</span>m</span>}\mathrm{<span><span>a</span>a</span>}\mathrm{<span><span>x</span>x</span>}}<span><span>(</span>(</span>\mathrm{<span><span>1</span>1</span>}<span><span>+</span>+</span>\mathrm{<span><span>a</span>a</span>}<span><span>)</span>)</span>\\ {\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>i</span>i</span>}<span><span>,</span>,</span>\mathrm{<span><span>k</span>k</span>}}^{\mathrm{<span><span>d</span>d</span>}}<span><span>=</span>=</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>m</span>m</span>}\mathrm{<span><span>a</span>a</span>}\mathrm{<span><span>x</span>x</span>}}<span><span>(</span>(</span>\mathrm{<span><span>1</span>1</span>}<span><span>-</span>-</span>\mathrm{<span><span>a</span>a</span>}<span><span>)</span>)</span>\end{array}\right.$当SOC_iⁱⁿ≤SOC_i,k≤SOC_i^max，$b=\sqrt{\frac{{\mathrm{SOC}}_{i,k}-{\mathrm{SOC}}_i^{\mathrm{in}}}{{\mathrm{SOC}}_i^{\max }-{\mathrm{SOC}}_i^{\mathrm{in}}}}$时：When SOC_iⁱⁿ ≤ SOC_i,k ≤ SOC_i^max ,$b=\sqrt{\frac{{\mathrm{SOC}}_{i,k}-{\mathrm{SOC}}_i^{\mathrm{in}}}{{\mathrm{SOC}}_i^{\max }-{\mathrm{SOC}}_i^{\mathrm{in}}}}$ Time:$\left\{\begin{array}{c}{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>i</span>i</span>}<span><span>,</span>,</span>\mathrm{<span><span>k</span>k</span>}}^{\mathrm{<span><span>c</span>c</span>}}<span><span>=</span>=</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>m</span>m</span>}\mathrm{<span><span>a</span>a</span>}\mathrm{<span><span>x</span>x</span>}}<span><span>(</span>(</span>\mathrm{<span><span>1</span>1</span>}<span><span>+</span>+</span>\mathrm{<span><span>b</span>b</span>}<span><span>)</span>)</span>\\ {\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>i</span>i</span>}<span><span>,</span>,</span>\mathrm{<span><span>k</span>k</span>}}^{\mathrm{<span><span>d</span>d</span>}}<span><span>=</span>=</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>m</span>m</span>}\mathrm{<span><span>a</span>a</span>}\mathrm{<span><span>x</span>x</span>}}<span><span>(</span>(</span>\mathrm{<span><span>1</span>1</span>}<span><span>-</span>-</span>\mathrm{<span><span>b</span>b</span>}<span><span>)</span>)</span>\end{array}\right.$当SOC_i,k≤SOC_i^min时：When SOC_i,k ≤ SOC_i^min :$\left\{\begin{array}{c}{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>i</span>i</span>}<span><span>,</span>,</span>\mathrm{<span><span>k</span>k</span>}}^{\mathrm{<span><span>c</span>c</span>}}<span><span>=</span>=</span>{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>m</span>m</span>}\mathrm{<span><span>a</span>a</span>}\mathrm{<span><span>x</span>x</span>}}\\ {\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>i</span>i</span>}<span><span>,</span>,</span>\mathrm{<span><span>k</span>k</span>}}^{\mathrm{<span><span>d</span>d</span>}}<span><span>=</span>=</span>\mathrm{<span><span>0</span>0</span>}\end{array}\right.$当SOC_i,k≤SOC_i^max时：When SOC_i,k ≤ SOC_i^max :$\left\{\begin{array}{c}{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>i</span>i</span>}<span><span>,</span>,</span>\mathrm{<span><span>k</span>k</span>}}^{\mathrm{<span><span>c</span>c</span>}}<span><span>=</span>=</span>\mathrm{<span><span>0</span>0</span>}\\ {\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>i</span>i</span>}<span><span>,</span>,</span>\mathrm{<span><span>k</span>k</span>}}^{\mathrm{<span><span>d</span>d</span>}}<span><span>=</span>=</span>{\mathrm{<span><span>K</span>K</span>}}_{\mathrm{<span><span>m</span>m</span>}\mathrm{<span><span>a</span>a</span>}\mathrm{<span><span>x</span>x</span>}}\end{array}\right.$在上述式中，SOC_i,k为k时刻第i辆电动汽车电池的荷电状态；SOC_i^min为第i辆电动汽车允许最小荷电状态；SOC_i^max为第i辆电动汽车允许最大荷电状态；SOC_iⁱⁿ为第i辆电动汽车的初始荷电状态；K_max为最大充/放电下垂系数；K^c_i,k为第i辆电动汽车，在k时刻充电下垂系数；K^d_i,k为第i辆电动汽车，在k时刻放电下垂系数。In the above formula, SOC_i,k is the state of charge of the battery of the i-th electric vehicle at time k; SOC_i^min is the allowable minimum state of charge of the i-th electric vehicle; SOC_i^max is the allowable maximum charge of the i-th electric vehicle State of charge; SOC_iⁱⁿ is the initial state of charge of the i-th electric vehicle; K_max is the maximum charge/discharge droop coefficient; K^c_i,k is the charge droop coefficient of the i-th electric vehicle at time k; K^d_{i , k} is the i-th electric vehicle, the discharge droop coefficient at time k.