A method for setting the number of charging piles based on charging and changing of electric buses

Abstract

The present invention discloses a method for setting the number of charging piles considering the strategy of charging and switching of electric buses. First, various parameters related to the charging demand of electric buses, various parameters related to charging stations, and relevant parameters of electric buses entering charging stations are input; secondly, according to the number of buses that need to be charged at each bus station, a constraint for the electric bus to select charging piles nearby is established; then, according to the arrival time of the vehicles charged at each charging pile, a constraint for bus charging and switching is established; finally, according to the selection of charging piles for buses that need to be charged at each bus station, the weighted sum of the charging pile access cost and the charging pile layout cost related to the driving time in the research period is minimized as the goal, and the optimal number of charging piles in the charging station is determined. The present invention reasonably dispatches the buses that need to be charged, while ensuring that the buses can be charged without queuing, and making the most of the charging piles in the station.

Description

Technical Field

[0001] The present invention belongs to the field of intelligent transportation, and relates to the technical field of dynamic scheduling of urban bus lines. More specifically, it relates to a method for setting the number of charging piles taking into account an electric bus charging and changing strategy. Background Art

[0002] Due to the limited driving range, electric buses need to be charged midway, so a certain charging infrastructure needs to be deployed for electric buses. At present, electric buses are mainly divided into three categories, including plug-in charging stations, battery swap stations and wireless charging lanes. Wireless charging lanes are expensive and limited in practical applications. Plug-in charging stations take a long time to charge, and the battery swap process at the battery swap station can shorten the charging time of the bus, but it currently takes about 10 minutes to swap batteries. Therefore, further research will be conducted on how to reduce the charging time of buses.

[0003] Therefore, the present invention proposes a method for setting the number of charging piles based on electric bus charging and car swapping. For vehicles that need to be charged, a car swapping strategy is proposed, that is, after the vehicle enters the charging pile, it can be charged without queuing. The "spare car" with full charge in the charging pile continues to complete the driving task of the charging vehicle, which can reduce the time the charging vehicle stays in the station. In addition, this article studies the bus charging and car swapping strategy and further determines the optimal number of charging piles in the charging station. How to arrange the vehicle charging scheduling plan and determine the optimal number of charging piles by establishing bus charging and car swapping constraints is the key problem to be solved by this patent.

[0004] After searching the literature on existing technologies, it was found that most of the literature charges electric buses through plug-in charging stations, battery swap stations and wireless charging lanes, and most of the research is about the site selection of charging stations, with less optimization of the number of charging piles in the station. There is currently no research on the optimal layout of charging piles for charging and swapping strategies. Summary of the invention

[0005] Technical problem: In view of the shortcomings of existing research, the purpose of the present invention is to provide a method for setting the number of charging piles based on electric bus charging and changing. According to the buses that need to be charged at each station, the charging scheduling plan of each station is reasonably arranged so that each charging pile can complete the car changing process. The optimal layout plan of the charging piles is determined with the goal of minimizing the total system cost.

[0006] Technical solution: To solve the above technical problems, a method for setting the number of charging piles based on electric bus charging and changing vehicles of the present invention comprises the following steps:

[0007] Step 1: Input various parameters related to the charging demand of electric buses, including the number of buses that need to be charged at each station, the time when each bus enters the charging station at the corresponding bus station, input various parameters related to the charging station, including the alternative location of the charging station, the maximum number of charging piles allowed in the station, the time it takes for the vehicle to be fully charged, the transfer time of passengers in the charging station, the charging pile access cost per unit time, the unit charging pile layout cost, input the relevant parameters of the electric bus entering the charging station, including the distance between the charging station and the bus station where the charging demand is generated, and the average driving speed of the electric bus;

[0008] Step 2: According to the number of buses that need to be charged at each bus stop, establish the constraint of electric buses selecting the nearest charging pile, and calculate the charging pile access cost related to the travel time during the study period;

[0009] Step 3: Based on the time when each bus enters the charging station at the corresponding bus stop and the travel time between the bus and the selected charging station, calculate the time when each bus arrives at the corresponding charging pile in the charging station. By comparing the time interval when the same charging pile arrives at the bus in close proximity with the time required for the vehicle to be fully charged and the time for the passenger to change buses, establish the constraint that the bus in the station can charge and change buses without waiting in line, and calculate the corresponding charging pile deployment cost;

[0010] Step 4: Based on the selection of charging piles for buses that need to be charged at each bus stop, determine the optimal number of charging piles in the charging station with the goal of minimizing the weighted sum of the charging pile access cost and the charging pile layout cost related to the driving time during the study period.

[0011] In the present invention, step 1 comprises the following steps:

[0012] Input various parameters related to the charging demand of electric buses, including: N represents the number of buses that need to be charged at all stations, and each vehicle that needs to be charged can be represented as n∈{1,2,…,N}; represents the time when vehicle n enters the charging station, in units of min; input various parameters related to the charging station, including: P represents the set of candidate charging stations, then each charging station can be represented as p, p∈P; M p represents the maximum number of charging piles allowed in the charging station p, then each charging pile in the charging station can be represented as m∈{1,2,…,M p}; Use t s The time it takes to fully charge a bus, in min, t r Indicates the transfer time of passengers in the charging station, in minutes; C2 represents the charging pile access cost per unit time, in yuan / min; C3 represents the unit charging pile layout cost, in yuan / unit; Input the relevant parameters of the electric bus entering the charging station, including: n,prepresents the distance between the station where vehicle n is located at the initial moment and the charging station p, in km; v represents the average speed of the electric bus, in km / h;

[0013] In the present invention, according to the number of buses that need to be charged at each bus station, a constraint for electric buses to select nearby charging piles is established, and the charging pile access cost related to the driving time during the study period is calculated, including the following steps:

[0014] Step 21: According to the number of buses that need to be charged at each bus stop, establish the constraint that electric buses select the nearest charging pile, as shown in formula (1):

[0015]

[0016] In formula (2), Y n,p,m is a binary variable, Y n,p,m =1 means vehicle n chooses the mth charging pile in charging station p to charge, otherwise it does not choose, V p,m is a binary variable, V p,m =1 means that the mth charging pile in the charging station p needs to be put into use, otherwise it will not be put into use;

[0017] Step 22: Calculate the charging pile access cost related to the driving time, as shown in formula (2):

[0018]

[0019] In formula (2), l n,p represents the distance between the station where vehicle n is located at the initial moment and the charging station p, in km; v represents the average speed of the electric bus, in km / h; C2 represents the charging pile access cost per unit time, in yuan / min; C B It represents the total access cost of charging piles considering the travel time of electric buses, in yuan;

[0020] In the present invention, the time for each bus to arrive at the corresponding charging pile in the charging station is calculated according to the time when each vehicle enters the charging station at the corresponding bus station and the travel time between the vehicle and the selected charging station. By comparing the time interval when the same charging pile arrives at the bus in close proximity with the time required for the vehicle to be fully charged and the time for the passenger to change buses, a constraint is established that the bus in the station can charge and change buses without waiting in line, and the corresponding charging pile deployment cost is calculated, including the following steps:

[0021] Step 31: According to the time when vehicle n enters the charging station at the corresponding bus stop The unit is min, the travel time t between vehicle n and the selected charging station p n,p , in min, calculates the time T for vehicle n to reach the corresponding charging pile m in charging station pn,p,m , in units of min, as shown in formula (3):

[0022]

[0023] Step 32: By comparing the time interval between buses that arrive at the same charging pile in close proximity with the time required for the vehicle to be fully charged, a constraint is established that buses in the station can charge and change vehicles without waiting in line, as shown in formulas (4)-(5):

[0024]

[0025]

[0026] In formulas (4)-(5), T n',p,m represents the time when vehicle n' arrives at the corresponding charging pile m in charging station p; Y n',p,m =1 means that vehicle n' selects the corresponding charging pile m in charging station p for charging, otherwise it does not select; x n,n',p,m is a binary variable; M represents a very large positive number; t s Indicates the time it takes for the bus to be fully charged, in min, t r Indicates the transfer time of passengers in the charging station, in minutes;

[0027] Step 33: Constrain the maximum number of charging times of each charging pile for the bus entering the charging pile and within the research time range T, as shown in formulas (6)-(9):

[0028]

[0029] p max =ceil(T / (t s +t r )) (7)

[0030]

[0031]

[0032] In formulas (9)-(10), p max represents the maximum number of charging times for each charging pile, T represents the research time range, in min;

[0033] Step 34: Calculate the corresponding charging pile deployment cost, as shown in formula (10):

[0034]

[0035] In formula (10), C3 represents the unit charging pile deployment cost, in RMB per unit; C CIt represents the total cost of charging pile deployment, in yuan;

[0036] In the present invention, step 4 comprises the following steps:

[0037] Step 4: Taking the weighted sum of the charging pile access cost and the charging pile layout cost related to the driving time in the study period as the minimum, determine the optimal number of charging piles in the charging station. The objective function is shown in formula (11):

[0038] Minimize C=C B +C C (11)

[0039] In formula (11), C represents the total cost of the model, in yuan.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] The method of the present invention aims at the problem of charging pile layout on urban bus lines, and proposes a charging and switching strategy for electric buses. According to the selection of charging piles for each vehicle, the optimal layout of charging piles is calculated and obtained. The charging and switching strategy proposed by the present invention allows buses to charge without queuing, and to switch with fully charged "spare vehicles", so as to reduce the delay of bus driving tasks as much as possible. In addition, the optimal number of charging piles in the charging station is also obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is the overall flow chart of the present invention;

[0043] Figure 2 This is a schematic diagram of the bus stop where the charging vehicle is located;

[0044] Figure 3 Schematic diagram of each charging station. DETAILED DESCRIPTION

[0045] The following is combined with Figure 1-3 The present invention is further described in detail with reference to the accompanying drawings and embodiments, but the embodiments of the present invention are not limited thereto. The embodiments of the present invention are not limited by the examples described above, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

[0046] Example 1

[0047] Construct a square with a side length of 25 km. The four bus stops that generate charging needs are located at the four vertices of the square, as shown in the figure below. Figure 2As shown, the four bus stops are A, B, C, and D. The number of vehicles that need to be charged is 3, 2, 2, and 3 respectively. The total number of vehicles that need to be charged is N = 10. All charging stations use the fast charging mode. The time it takes for a vehicle to be fully charged is t s = 15min, the transfer time of passengers in the charging station t r =5min; there are 5 charging stations, namely p1, p2, p3, p4, p5, as shown in the attached Figure 3 As shown; the maximum number of charging piles allowed for each charging station is M p =15, the average speed of the electric bus is v = 20 km / h, and the distance between the station where the vehicle n is located and the charging station p at the initial moment is l n,p As shown in Table 1, the time when vehicle n enters the charging station As shown in Table 2, the charging pile access cost per unit time C2 = 100 yuan / min, and the unit charging pile deployment cost C3 = 10,000 yuan / piece.

[0048] Table 1: Distances between charging vehicles at each bus stop and each alternative charging station

[0049]

[0050]

[0051] Table 2: The time when the vehicle starts to drive to the charging station

[0052]

[0053] Example 2

[0054] According to step 2, step 3, step 4 formula (1)-(10) and objective function formula (11), the optimal charging station layout plan of Example 1 is calculated. At the same time, the charging station selection plan for vehicles that need to be charged at each bus stop and the arrival time of each charging bus at the selected charging station are obtained. The results are shown in Table 3.

[0055] Table 3: Optimal layout of charging stations

[0056]

[0057] Using the method of the present invention, the value of the objective function C is 60,500 yuan.

Claims

1. A method for setting the number of charging piles based on charging and changing electric buses, characterized in that: The method comprises the following steps: Step 1: Input various parameters related to the charging demand of electric buses, including the number of buses that need to be charged at each station, the time when each bus enters the charging station at the corresponding bus station, input various parameters related to the charging station, including the alternative location of the charging station, the maximum number of charging piles allowed in the station, the time it takes for the vehicle to be fully charged, the transfer time of passengers in the charging station, the charging pile access cost per unit time, the unit charging pile layout cost, input the relevant parameters of the electric bus entering the charging station, including the distance between the charging station and the bus station where the charging demand is generated, and the average driving speed of the electric bus; Step 2: According to the number of buses that need to be charged at each bus stop, establish the constraint of electric buses selecting the nearest charging pile, and calculate the charging pile access cost related to the travel time during the study period; Step 3: Based on the time when each bus enters the charging station at the corresponding bus stop and the travel time between the bus and the selected charging station, calculate the time when each bus arrives at the corresponding charging pile in the charging station. By comparing the time interval when the same charging pile arrives at the bus in close proximity with the time required for the vehicle to be fully charged and the time for the passenger to change buses, establish the constraint that the bus in the station can charge and change buses without waiting in line, and calculate the corresponding charging pile deployment cost; Step 4: Based on the selection of charging piles for buses that need to be charged at each bus stop, determine the optimal number of charging piles in the charging station with the goal of minimizing the weighted sum of the charging pile access cost and the charging pile layout cost related to the driving time during the study period.

2. According to claim 1, a method for setting the number of charging piles based on electric bus charging and changing vehicles is characterized in that: The step 1 comprises the following steps: Input various parameters related to the charging demand of electric buses, including: N represents the number of buses that need to be charged at all stations, and each vehicle that needs to be charged is represented by n∈{1,2,…,N}; represents the time when vehicle n enters the charging station, in units of min; input various parameters related to the charging station, including: P represents the set of candidate charging stations, each charging station is represented by p, p∈P; M p represents the maximum number of charging piles allowed in the charging station p, then each charging pile in the charging station is represented by m∈{1,2,…,M p }; Use t s Indicates the time it takes for a bus to be fully charged, in minutes, and in t r Indicates the transfer time of passengers in the charging station, in minutes; input the relevant parameters of the electric bus entering the charging station, including: n,p represents the distance between the station where vehicle n is located at the initial moment and the charging station p, in km; v represents the average speed of the electric bus, in km / h; The step 2 comprises the following steps: Step 21: According to the number of buses that need to be charged at each bus stop, establish the constraint that electric buses select the nearest charging pile, as shown in formula (1): In formula (2), Y n,p,m is a binary variable, Y n,p,m =1 means vehicle n chooses the mth charging pile in charging station p to charge, otherwise it does not choose, V p,m is a binary variable, V p,m =1 means that the mth charging pile in charging station p needs to be put into use, otherwise it will not be put into use; Step 22: Calculate the charging pile access cost related to the driving time, as shown in formula (2): In formula (2), l n,p represents the distance between the station where vehicle n is located at the initial moment and the charging station p, in km; v represents the average speed of the electric bus, in km / h; C2 represents the charging pile access cost per unit time, in yuan / min; C B It represents the total access cost of charging piles considering the travel time of electric buses, in yuan; The step 3 comprises the following steps: Step 31: According to the time when vehicle n enters the charging station The unit is min, the travel time t between vehicle n and the selected charging station p n,p , in min, calculates the time T for vehicle n to reach the corresponding charging pile m in charging station p n,p,m , in units of min, as shown in formula (3): Step 32: By comparing the time interval between buses that arrive at the same charging pile in close proximity with the time required for the vehicle to be fully charged, a constraint is established that buses in the station can charge and change vehicles without waiting in line, as shown in formulas (4)-(5): In formulas (4)-(5), T n′,p,m represents the time when vehicle n′ arrives at the corresponding charging pile m in charging station p; Y n′,p,m =1 means that vehicle n′ selects the corresponding charging pile m in charging station p to charge, otherwise it does not select; x n,n′,p,m is a binary variable; M represents a very large positive number; t s Indicates the time it takes for the bus to be fully charged, in min, t r Indicates the transfer time of passengers in the charging station, in minutes; Step 33: Constrain the maximum number of charging times of each charging pile for the bus entering the charging pile and within the research time range T, as shown in formulas (6)-(9): p max =ceil(T / (t s +t r )) (7) In formulas (7)-(8), p max represents the maximum number of charging times for each charging pile, T represents the research time range, in min; Step 34: Calculate the corresponding charging pile deployment cost, as shown in formula (10): In formula (10), C3 represents the unit charging pile deployment cost, in RMB per unit; C C It represents the total cost of charging pile deployment, in yuan; The step 4 comprises the following steps: Step 4: Taking the weighted sum of the charging pile access cost and the charging pile layout cost related to the driving time in the study period as the minimum, determine the optimal number of charging piles in the charging station. The objective function is shown in formula (11): Minimize C=C B +C C (11) In formula (11), C represents the total cost of the model, in yuan.

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