A method for selecting a charging station location based on charging at the terminal station of electric buses on fixed routes

Abstract

The present invention discloses a method for selecting a charging station site based on charging at the terminal of an electric bus on a fixed route. First, various parameters related to the bus route, various parameters related to the bus driving range, and parameters related to bus charging are input; secondly, the electric bus is constrained to travel back and forth only on a fixed route, and the distance traveled by the bus to the terminal in sequence is calculated according to the length of the bus on each route, and the distance traveled by each electric bus is compared with the maximum allowed driving distance and the minimum driving distance, and a constraint is established to determine whether the vehicle needs to be charged at each terminal; then, according to the charging scheduling plan of the vehicle on the fixed route, the location of the charging station and the minimum total number of charging times are taken as the objective function to determine the optimal location scheme of the charging station based on charging at the terminal bus. The present invention can ensure the service level of passengers and determine the optimal location scheme of the charging station by reasonably scheduling charging buses on fixed routes.

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, and more specifically, to a charging station site selection method based on charging at the terminal station of a fixed-line electric bus. Background Art

[0002] The full popularization of electric buses is the development trend of public transportation in the future. Due to the limited mileage of electric buses, they need to be charged midway. The charging scheduling of electric buses and the location of charging stations have become one of the research hotspots in recent years. In the field of electric bus scheduling, in order to improve the utilization rate of the fleet, buses are allowed to change routes flexibly, which we call a variable route strategy. However, this strategy cannot guarantee the service level of passengers, and electric buses will mainly be based on fixed routes within the foreseeable time frame.

[0003] Therefore, the present invention carries out electric bus dispatching on fixed routes and proposes a charging station site selection method based on charging at the terminal stations of electric buses on fixed routes. For buses that need to be charged at the terminal stations of each route, the optimal site selection plan of the charging station is determined based on the remaining driving range of the bus on the fixed route and the charging station selection plan of each vehicle at the terminal station. This is the key problem to be solved by this patent.

[0004] After searching the literature on existing technologies, it was found that when it comes to the charging scheduling of electric buses, most of the literature adopts a variable route strategy, allowing electric buses to flexibly change their operating routes. Currently, there is no research on the charging scheduling of the first and last stations of fixed electric bus routes to determine the optimal location plan for charging stations. 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 charging station site selection method based on charging at the terminal of a fixed route electric bus. First, according to the mileage limit of the charging vehicle at the terminal, the charging plan of each vehicle is arranged. The buses that need to be charged at the terminal can choose different charging stations to determine their optimal site selection plan.

[0006] Technical solution: To solve the above technical problems, the present invention provides a charging station site selection method based on charging at the terminal station of a fixed-line electric bus, comprising the following steps:

[0007] Step 1: Input various parameters related to bus routes, including the total number of bus routes within the research scope, the length of each bus route, and various parameters related to the bus driving range, including the distance traveled by each vehicle at the initial moment, the maximum driving distance allowed for electric buses, and the minimum driving distance allowed to start charging. Input relevant parameters for bus charging, including the distance between each alternative charging station and the first and last stations of each route, and the departure frequency of electric buses on each route;

[0008] Step 2: Constrain electric buses to travel back and forth on fixed routes. According to the length of buses on each route, calculate the distance traveled by the buses to the terminal stations in sequence, compare the distance traveled by each electric bus with the maximum and minimum allowed distances, and establish constraints to determine whether the vehicle needs to be charged at each terminal station;

[0009] Step 3: Update the vehicle's travel distance according to the charging status of each vehicle at each terminal station, and repeat step 2 to determine whether the vehicle needs to be charged next time;

[0010] Step 4: According to the charging situation of vehicles on fixed routes, the optimal location scheme of charging stations based on charging at bus terminals is determined with the weighted sum of charging station location and total charging times as the objective function.

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

[0012] Input various parameters related to bus routes, including: I represents the set of bus routes within the research scope, and each route can be represented as i∈I; J represents the i represents the number of virtual first and last stations of each line. Each virtual first and last station is numbered starting from 1. Then each first and last station can be represented as j∈{1,2,…,J i}; Use d i Indicates the length of bus line i in km; input various parameters related to the bus travel range, including: i,m,1 It represents the distance traveled by vehicle m on route i at the initial moment, in km; l max It indicates the maximum driving distance allowed by the electric bus, in km; l min represents the minimum driving distance allowed for the electric bus to start charging, in km; input bus charging related parameters, including: P represents the set of alternative charging stations, then each charging station can be represented by p∈P; d i,j,p represents the distance between each candidate charging station p and the first and last station j of each line i, in km; M i The frequency of electric bus departures on each route is measured in units of vehicles / h. C1 represents the unit charging station site selection cost in units of RMB / unit, and C2 represents the unit charging times cost in units of RMB / time.

[0013] In the present invention, step 2 establishes the charging station selection constraints for each vehicle according to the mileage restrictions of each bus at the terminal station, and includes the following steps:

[0014] Step 21: Establish a function expression for the charging station selected by the buses that need to charge at each terminal, as shown in formulas (1)-(2):

[0015]

[0016]

[0017] In formulas (1)-(2), R i,m,j,p is a binary variable, R i,m,j,p Indicates that the mth vehicle on route i chooses charging station p to charge at the virtual terminal j, otherwise it will not choose it; in formula (1), F p is a binary variable, F p =1 means that charging station p needs to be built, otherwise it does not need to be built;

[0018] Step 22: Constrain the electric bus to travel back and forth on a fixed route. According to the length of the buses on each route, calculate the distance traveled by the bus to the terminal station in sequence. Compare the distance traveled by each electric bus with the maximum and minimum allowed distances, and establish constraints for judging whether the vehicle needs to be charged at each terminal station, as shown in formulas (3)-(5):

[0019]

[0020]

[0021]

[0022] In formulas (3)-(5), L i,m,j It represents the distance traveled by the mth vehicle on line i when it arrives at the virtual terminal j, in km; M represents a very large positive number; l max Indicates the maximum allowed driving distance of an electric bus, in km; l min represents the minimum driving distance allowed for the electric bus to start charging, in km; in formula (5), d i Indicates the length of bus line i, in km;

[0023] In the present invention, step 3 arranges the next charging plan of each electric bus by calculating the mileage traveled by each electric bus at the charging station, and includes the following steps:

[0024] Step 31: Update the vehicle's travel distance according to the charging status of each vehicle at each terminal station, as shown in formulas (6)-(7);

[0025]

[0026]

[0027] In formula (6), d i,m+1,prepresents the distance between the m+1th virtual terminal on line i and charging station p, in km. In formulas (6)-(7), L i,m,j+1 It indicates the distance traveled by the mth vehicle on line i when it arrives at the virtual terminal j+1, in km;

[0028] Step 32: Linearize the formula in step 31, as shown in formulas (8)-(9):

[0029]

[0030]

[0031] In formulas (8)-(9), d i,j+1,p It represents the distance between the candidate charging station p and the first and last station j+1 of each line i, in km;

[0032] Step 33: Within the maximum bus entry range allowed by the charging station, buses that need to be charged can enter the charging station to charge, as shown in formula (10):

[0033]

[0034] In formula (10), d i,j,p represents the distance between the jth virtual terminal on line i and charging station p, in km; D p Indicates the maximum driving range of charging buses allowed by charging station p, in km;

[0035] Step 34: Limit the number of charging times at each charging station during the study period, as shown in formula (11);

[0036]

[0037] In formula (11), t p,max represents the maximum number of charging times allowed in charging station p during the study period;

[0038] In the present invention, step 4 comprises the following steps:

[0039] Step 4: According to the charging scheduling of vehicles on a fixed route, the optimal location of the charging station is determined with the location of the charging station and the minimum total number of charging times as the objective function. The objective function is shown in formula (12);

[0040]

[0041] In formula (12), C T It represents the total cost of the model, in Yuan. C1 represents the unit charging station site selection cost, in Yuan / unit. C2 represents the unit charging times cost, in Yuan / time.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] Compared with the electric bus dispatching strategy with variable routes, the method of the present invention can guarantee the service level of passengers and is more in line with people's travel methods and habits. In the foreseeable time range, electric buses are still mainly dispatched on fixed routes. The method of the present invention is based on the fixed route charging strategy and determines the optimal location scheme for electric buses at the first and last stops. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is the overall flow chart of the present invention;

[0045] Figure 2 It is a schematic diagram of the virtual first and last bus stops of a certain line and the bus charging scheduling diagram at each stop;

[0046] Figure 3 Schematic diagram of the locations of alternative charging stations. DETAILED DESCRIPTION

[0047] 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.

[0048] Example 1

[0049] Assume that the length of a bus route A is d A = 25km, the number of virtual first and last stations of the line J A =10, as attached Figure 2 As shown; the maximum driving distance allowed for electric buses is l max =180km, the minimum driving distance allowed for electric buses to start charging l min = 0km; there are 5 alternative charging stations P, namely p1, p2, p3, p4, and p5. Figure 3 As shown; the departure frequency of electric buses on route A is M A = 10 vehicles / h; unit charging station site selection cost C1 = 1,000,000 yuan / unit, unit charging cost C2 = 100 yuan / time; the distance d between the jth virtual terminal on line A and charging station p A,j,p As shown in Table 1; at the initial moment, the distance L traveled by vehicle m on route A A,m,1 As shown in Table 2.

[0050] Table 1: Distance between the jth virtual terminal and charging station p on route A

[0051]

[0052] Table 2: Description of the distance traveled by vehicle m on route A at the initial moment

[0053]

[0054]

[0055] Example 2

[0056] According to step 2, step 3, step 4, formulas (1)-(11) and objective function formula (12), the optimal charging station deployment plan of Example 1 is calculated and obtained, and the charging station selected by the electric bus at each terminal is obtained, as shown in Table 3.

[0057] Table 3: Optimal charging station location and bus charging scheduling scheme

[0058]

[0059] Using the method of the present invention, the objective function C T The value is 2006000 yuan.

Claims

1. A method for selecting a charging station site for charging electric buses at the terminal station of a fixed route, characterized in that: The method comprises the following steps: Step 1: Input various parameters related to bus routes, including: I represents the set of bus routes within the research scope, and each route can be represented as i∈I; J represents the bus route set within the research scope, and ... i represents the number of virtual first and last stations of each line. Each virtual first and last station is numbered starting from 1. Then each first and last station can be represented as j∈{1,2,…,J i }; Use d i Indicates the length of bus line i in km; input various parameters related to the bus travel range, including: i,m,1 It represents the distance traveled by vehicle m on route i at the initial moment, in km; l max It indicates the maximum driving distance allowed by the electric bus, in km; l min represents the minimum driving distance allowed for the electric bus to start charging, in km; input bus charging related parameters, including: P represents the set of alternative charging stations, then each charging station can be represented by p∈P; d i,j,p It represents the distance between each alternative charging station p and the first and last station j of each line i, in km; M i The frequency of electric bus departures on each line is expressed in units of vehicles / h. C1 represents the unit charging station site selection cost in units of RMB / unit. C2 represents the unit charging times cost in units of RMB / time. Step 2: Constrain electric buses to travel back and forth on fixed routes. According to the length of buses on each route, calculate the distance traveled by the buses to the terminal stations in sequence, compare the distance traveled by each electric bus with the maximum and minimum allowed distances, and establish constraints to determine whether the vehicle needs to be charged at each terminal station; The step 2 comprises the following steps: Step 21: Establish a function expression for the charging station selected by the buses that need to charge at each terminal, as shown in formulas (1)-(2): In formulas (1)-(2), R i,mj,p is a binary variable, R i,m,j,p Indicates that the mth vehicle on route i chooses charging station p to charge at the virtual terminal j, otherwise it will not choose it; in formula (1), F p is a binary variable, F p =1 means that charging station p needs to be built, otherwise it does not need to be built; Step 22: Constrain the electric bus to travel back and forth on a fixed route. According to the length of the buses on each route, calculate the distance traveled by the bus to the terminal station in sequence. Compare the distance traveled by each electric bus with the maximum and minimum allowed distances, and establish constraints for judging whether the vehicle needs to be charged at each terminal station, as shown in formulas (3)-(5): In formulas (3)-(5), L i,m,j It represents the distance traveled by the mth vehicle on line i when it arrives at the virtual terminal j, in km; M represents a very large positive number; l max Indicates the maximum allowed driving distance of an electric bus, in km; l min represents the minimum driving distance allowed for the electric bus to start charging, in km; in formula (5), d i Indicates the length of bus line i, in km; Step 3: Update the vehicle's travel distance according to the charging status of each vehicle at each terminal station, and repeat step 2 to determine whether the vehicle needs to be charged next time; Step 4: According to the charging status of vehicles on fixed routes, the optimal location scheme for charging stations based on charging at bus terminals is determined with the minimum weighted sum of charging station location and total charging times as the objective function.

2. According to claim 1, a charging station site selection method based on charging at the terminal station of a fixed-line electric bus is characterized in that: Described step 3, comprises the following steps: Step 31: Update the vehicle's travel distance according to the charging status of each vehicle at each terminal station, as shown in formulas (6)-(7): In formula (6), d i,m+1,p represents the distance between the m+1th virtual terminal on line i and charging station p, in km. In formulas (6)-(7), L i,m,j+1 It indicates the distance traveled by the mth vehicle on line i when it arrives at the virtual terminal j+1, in km; Step 32: Linearize the formula in step 31, as shown in formulas (8)-(9): In formulas (8)-(9), d i,j+1,p It represents the distance between the candidate charging station p and the first and last station j+1 of each line i, in km; Step 33: Within the maximum bus entry range allowed by the charging station, buses that need to be charged can enter the charging station to charge, as shown in formula (10): In formula (10), d i,j,p represents the distance between the jth virtual terminal on line i and charging station p, in km; D p Indicates the maximum driving range of charging buses allowed by charging station p, in km; Step 34: Limit the number of charging times at each charging station during the study period, as shown in formula (11): In formula (11), t p,max It represents the maximum number of charging times allowed in charging station p during the study period.

3. According to claim 1, a charging station site selection method based on charging at the terminal station of a fixed-line electric bus is characterized in that: The step 4 comprises the following steps: Step 4: According to the charging scheduling of vehicles on fixed routes, the optimal location scheme of charging stations is determined with the location of charging stations and the minimum total number of charging times as the objective function. The objective function is shown in formula (12): In formula (12), C T It represents the total cost of the model, in Yuan. C1 represents the unit charging station site selection cost, in Yuan / unit. C2 represents the unit charging times cost, in Yuan / time.

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