A bus fast-charging station orderly charging method considering battery dynamic charging loss

Abstract

The application provides a bus fast-charging station orderly charging method considering battery dynamic charging loss, comprising: determining the power demand meeting bus line operation according to the operation time of the charging station, equipment power limit, quantity limit and bus departure plan; establishing a battery heat loss model and the relationship between charging energy conversion efficiency and the actual charging power of the vehicle-mounted energy storage system based on a first-order RC circuit model; taking the minimum actual power consumption of the charging station in a day or the minimum actual electricity cost of the charging station in a day as an objective function, wherein the battery heat loss is considered, and an optimization model is established with the charging station operation time, charging pile number, charging pile maximum power, power distribution capacity, electric bus travel power demand, electric bus charging time continuity as constraint conditions; using piecewise linearization to convert the nonlinear optimization objective function model into a mixed integer convex programming problem, and solving the mixed integer convex programming problem to obtain the optimal charging plan, including the optimal charging time and corresponding charging power of each vehicle. The method improves the charging energy conversion efficiency, reduces the battery heat loss and prolongs the service life of the battery, reduces the charging cost of the bus while improving the charging energy conversion efficiency, and improves the economy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of public transportation, in particular to a bus fast-charging station orderly charging method considering battery dynamic charging loss. BACKGROUND

[0002] With the rapid development of the country and the gradual improvement of people's environmental awareness, sustainable development has become an inevitable trend. The number of new energy vehicles in China and the market share have grown rapidly. As the "pioneer" of electric vehicles in the Chinese market, the share of electric buses is increasing, and the impact of their charging on the safe and stable operation of the power grid cannot be ignored. The operation and charging of electric buses and electric vehicles are quite different. For the same bus operation line, the operation route and time are relatively fixed. The battery capacity and charging power of electric buses are much larger than those of electric private cars. One of the main charging modes for electric buses is the fast charging mode of returning to the station with piles, and large-scale disordered charging will have an adverse impact on the power grid, intensify the peak of the power grid, and also lead to the problem of over-planning of charging piles, increasing the construction cost of charging piles and the cost of electricity.

[0003] The patent CN111619394 proposes an orderly charging and discharging method for electric buses based on time-of-use electricity prices, taking the minimum charging cost of electric buses as the optimization target, without considering the relationship between charging power and battery heat loss. The current research on orderly charging of electric vehicles is mainly based on time-of-use electricity prices, aiming to reduce the charging cost of users or reduce the peak-valley difference of load to guide electric vehicles to charge orderly, but none of them considers the relationship between charging power and battery heat loss, resulting in low actual charging efficiency of the battery when using high-power charging, high actual electricity consumption, and waste of electric energy and increase of charging cost. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application aims to provide an orderly charging method for bus fast-charging stations considering battery dynamic charging loss, by establishing a dynamic charging loss model for the charging station, taking the minimum actual electricity consumption of the charging station in a day as the optimization target on the basis of meeting the electricity demand of the electric bus operation line and the operation requirements of the charging station, considering the relationship between the orderly charging power and the battery heat loss in the optimization target, and taking the operation time of the charging station, the number of charging piles, the maximum power of the charging piles, the distribution capacity and the electricity demand of the electric bus as the constraint conditions. The objective function is segmented and linearized, and the optimal charging plan is obtained by solving the model, including the optimal charging time and corresponding charging power of each vehicle. In combination with real-time electricity prices or time-of-use electricity prices, the charging energy conversion efficiency is further improved based on traditional orderly charging, the battery heat loss is reduced and the service life of the battery is prolonged, and in addition, the charging cost of the electric bus is reduced while the charging energy conversion efficiency is improved, improving the economy.

[0005] To solve the above technical problems, the technical scheme provided by the present application is:

[0006] A bus fast-charging station orderly charging method considering battery dynamic charging loss, comprising the following steps:

[0007] S1. According to the operation time of the charging station, the equipment power limit, the quantity limit and the bus departure plan, a charging demand model of the electric bus is established to determine the power demand that meets the operation of the bus line;

[0008] S2. Based on the first-order RC circuit model, a battery heating loss model and the relationship between the charging energy conversion efficiency and the actual charging power of the vehicle-mounted energy storage system are established;

[0009] The S2 comprises the following steps:

[0010] S2.1 Establish a battery efficiency model:

[0011] First, an equivalent circuit model of the battery is established. The battery charging process is constant current charging, and the charging current I bat remains unchanged, and no current passes through the polarization capacitor C1, which is represented by formula (3):

[0012] U bat =I bat ·(R0+R1)+U ocv (3)

[0013] In the formula, U bat is the terminal voltage of the lithium battery; U ocv is the open circuit voltage of the battery; I bat is the charging current; R0 is the ohmic internal resistance of the battery, and R1 is the polarization internal resistance of the battery;

[0014] The charging energy loss E loss of the complete charging process of the electric bus battery is represented as:

[0015]

[0016] In the formula, T c is the battery charging time, C1 is the polarization capacitance of the battery, and U C is the voltage across the polarization capacitor;

[0017] The charging energy loss power P loss is the derivative of the charging energy loss E loss with respect to time t c ,

[0018]

[0019] η is the battery charging energy conversion efficiency of the electric bus at any time b is expressed as:

[0020]

[0021] In the formula, U bat is the terminal voltage of the lithium battery, I bat is the battery charging current, R0 is the battery ohmic resistance, R1 is the battery polarization resistance, P loss is the battery charging energy loss power;

[0022] S2.2 The relationship between the charging energy conversion efficiency considering the battery heat loss and the actual charging power of the vehicle-mounted energy storage system is expressed as:

[0023]

[0024] In the formula, t represents any charging time, T represents the number of unit time divided in a day; P t g is the actual power consumed by the power distribution network; P t ch is the actual charging power of the vehicle-mounted energy storage system, which is expressed as the product of the open-circuit voltage U ocv and the battery charging current I bat ;

[0025] The following derivation and simplification are made for η b , and the relationship between P t ch is obtained:

[0026]

[0027] S3. Taking the minimum actual power consumption of the charging station in a day or the minimum actual electricity cost of the charging station in a day as the objective function, considering the battery heat loss, the charging station operation time, the number of charging piles, the maximum power of the charging pile, the power distribution capacity, the electric bus travel power demand, and the continuity of the charging time as the constraint conditions, a nonlinear optimization objective function model is established;

[0028] S4. The nonlinear optimization objective function model in S3 planning is converted into a mixed integer convex programming problem using piecewise linearization, and the optimal charging plan is obtained by solving the mixed integer convex programming problem, including the optimal charging time and the corresponding charging power of each vehicle.

[0029] Preferably,

[0030] All the buses in the charging demand model of the electric bus in S1 satisfy the complete line trip before the departure time of the bus, and the state of charge of the vehicle-mounted energy storage system at the departure time of the bus is

[0031]

[0032]

[0033] where j is the vehicle number; is the number of buses serving the route of vehicle j; is the first departure time, the last departure time and the departure interval of the route of vehicle j, respectively; j is the length of the route of vehicle j; n j is the number of times each bus needs to repeat the route of vehicle j; is the start time of the kth cycle of vehicle j; V j is the energy consumption per kilometer of the route of vehicle j; C p，j is the maximum energy of the energy storage system of vehicle j; soc low is the lower limit of SOC to ensure the safe operation of the vehicle considering the additional loss caused by traffic conditions, represents the SOC of vehicle j before departure in the kth cycle.

[0034] Preferably,

[0035] The objective function of S3 is to minimize the actual power consumption of the charging station in a day:

[0036]

[0037] where T represents the number of unit times divided in a day; Δt is the unit time, in this paper Δt = 60 s; J is the total number of vehicles served by the bus charging station; is the actual charging power of the energy storage system of the jth vehicle at time t.

[0038] Preferably,

[0039] The objective function of S3 is to minimize the actual power consumption of the charging station in a day:

[0040]

[0041] c(t) is the commercial electricity price of the charging station at time t in the city of operation.

[0042] Preferably,

[0043] The constraint condition of the objective function of S3 is:

[0044] S3.1 Time constraint: formula (14) represents that the bus cannot be charged when it is not at the charging station; formula (15) represents that all vehicles cannot be charged when the charging station stops business;

[0045]

[0046]

[0047] where d j，t is the state of charge of vehicle j at time t, d j，t ∈ {0, 1}, d j，t = 1 if the vehicle is in charging state, otherwise in non-charging state; is the set of time that bus j is not at charging station, where is the departure time of vehicle j in the kth round, is the return time of vehicle j in the kth round, n j is the total number of rounds that vehicle j has to circulate in a day; T close is the time that charging station is closed;

[0048] S3.2 Charging station equipment constraints: Equation (16) specifies that the number of charging piles that are in charging at the same time is less than or equal to the total number of charging equipment in the charging station N cs ; Equation (17) specifies that the maximum power of a single charging pile cannot exceed the safe power P cs ; Equation (18) specifies that the power distribution capacity of the entire charging station cannot exceed the maximum safe power P s of the charging station power distribution network;

[0049]

[0050]

[0051]

[0052] S3.3 Constraints on travel demand:

[0053]

[0054]

[0055]

[0056] Equation (19) represents that the SOC of each vehicle at the departure time of each round should be between the ratio of the energy required for a single trip and the maximum energy plus the lower limit of the SOC of the battery soc low and the set maximum SOC soc max ; Equation (20) represents the SOC of vehicle j at the kth departure time ​SOC of the vehicle at the moment is the SOC at the initial moment of the day plus the electricity charged into the vehicle before the moment, minus the electricity consumed before the trip; formula (21) represents that the electricity charged into the vehicle in a day meets the sum of the electricity required for the trip in a day, so as to ensure the recyclability of the charging strategy;

[0057]

[0058]

[0059] wherein y j，t and z j，t are the start and end decision variables of the continuous charging in the charging process of the vehicle numbered j after returning to the station, y j，t , z j，t ∈{0,1}; is the set of time periods of the vehicle j in the charging station after returning to the station, formulae (22)-(23) ensure that the charging strategy of the application is continuous in the time scale for each bus charging behavior.

[0060] Preferably,

[0061] The formula of the piecewise linearization in S4 is:

[0062]

[0063]

[0064]

[0065]

[0066] wherein, is an auxiliary constraint parameter, subscript x corresponds to the xth segment after linearization, represents that the charging power is located in the xth segment of the broken line segment after piecewise linearization, and the value is and are the upper and lower limit values of the xth segment of the segmented interval power P li，x ; K η，x and B η，x are linearization coefficients, reflecting the influence of the charging power ; and W x ={1,2,3}.

[0067] The beneficial effects of the application are:

[0068] The application considers the relationship between charging power and battery heat loss, introduces an electric bus orderly charging strategy model of battery heat loss, takes the minimum actual power consumption in a day as an objective function, improves the energy conversion efficiency of electric bus charging, reduces the heat loss of the battery and prolongs the service life of the battery, and improves the objective function by combining real-time electricity price or time-of-use electricity price, reduces the charging cost of the electric bus while improving the energy conversion efficiency of charging, and improves the economy.

[0069] The application uses a piecewise linearization method to linearize the established optimization objective function model including battery heat loss, and the piecewise linearization makes the model easy to solve under the condition of ensuring the accuracy of the total efficiency model; the complex nonlinear model is divided into several linear operations, which improves the solving speed and efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0070] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, which together with the embodiments of the application are used to explain the application, and do not constitute a limitation on the application. In the drawings:

[0071] Figure 1 A bus fast charging station orderly charging method considering battery dynamic charging loss

[0072] Figure 2 A first-order RC model schematic diagram DETAILED DESCRIPTION

[0073] The preferred examples of the application are described below in conjunction with the drawings, and it should be understood that the following examples are given only for the purpose of illustration, and are not intended to limit the scope of the application. Those skilled in the art can make various modifications and replacements to the application without departing from the spirit and principles of the application.

[0074] The application provides a bus fast charging station orderly charging method considering battery heat loss, a flow chart as shown in Figure 1 The method comprises the following steps:

[0075] S1. According to the operation time of the charging station, the equipment power limit, the quantity limit and the bus departure plan, a charging demand model of the electric bus is established to determine the power demand that meets the operation of the bus line.

[0076] S2. Based on the first-order IC circuit model, a battery heat loss model and the relationship between charging energy conversion efficiency and the actual charging power of the vehicle-mounted energy storage system are established.

[0077] S3. Taking the actual power consumption of the charging station in a day or the actual electricity cost of the charging station in a day as an objective function, wherein battery heating loss is considered, and taking charging station operation time, charging pile number, charging pile maximum power, power distribution capacity, electric bus travel power demand, electric bus charging time continuity as constraint conditions, a nonlinear optimization objective function model is established.

[0078] S4. The nonlinear optimization objective function model in S3 is converted into a mixed integer convex programming problem using piecewise linearization, and an optimal charging plan is obtained by solving the mixed integer convex programming problem, including optimal charging time and corresponding charging power of each vehicle.

[0079] Specifically, the charging demand model of the electric bus is established in S1, and the power demand meeting the operation requirements of the electric bus is obtained, including the following steps:

[0080] The bus charging station needs to meet the departure demand of multiple bus lines at the same time, and the travel demand of the bus line is determined by the departure table formulated by the operator. The case provides a departure time table of a certain bus station, as shown in Table 1.

[0081] Table 1

[0082]

[0083] The present application studies the charging demand of the electric bus, and guarantees that the state of charge of the vehicle-mounted energy storage system of all buses can meet the energy consumption of walking a complete line before the departure time:

[0084]

[0085]

[0086] In the formula, j is the vehicle number; is the number of bus vehicles serving the line of vehicle j; is the first departure time, the last bus time and the departure interval of the line of vehicle j, respectively; l j is the length of the running line of vehicle j; n j is the number of times each bus in the line served by vehicle j needs to be repeated; is the starting time of vehicle j in the kth cycle; V j is the unit kilometer energy consumption of the line served by vehicle j; C p，j is the maximum energy of the vehicle-mounted energy storage system of vehicle j; soc low is the SOC safety lower limit considering the additional loss possibly caused by traffic conditions and other factors to ensure safe operation of the vehicle, represents the SOC of vehicle j before the kth cycle departure.

[0087] S2.1 establishes the battery efficiency model:

[0088] S2.1 establishes the battery efficiency model:

[0089] First, an equivalent circuit model of the battery is established. The present application selects a first-order RC equivalent circuit model to analyze the battery efficiency, as shown in the accompanying drawings. Figure 2 As shown in the accompanying drawings, the battery charging process is constant-current charging, and the charging current I bat remains unchanged, and no current passes through the polarization capacitor C1, so the model can be represented by formula (3):

[0090] U bat = I bat ·(R0+R1)+U ocv (3)

[0091] In the formula, U bat is the terminal voltage of the lithium battery; U ocv is the open-circuit voltage of the battery; I bat is the charging current; R0 is the ohmic internal resistance of the battery, and R1 is the polarization internal resistance of the battery.

[0092] The charging energy loss E loss of the complete charging process of the battery of the electric bus can be represented as:

[0093]

[0094] In the formula, T c is the duration of one charging of the battery, C1 is the polarization capacitance of the battery, and U C is the voltage across the polarization capacitor.

[0095] The charging energy loss power P loss can be represented as the derivative of the charging energy loss E loss with respect to time t c , and is represented as:

[0096]

[0097] Therefore, the battery charging energy conversion efficiency η b at any time can be represented as:

[0098]

[0099] The relationship between the charging energy conversion efficiency and the actual charging power of the vehicle-mounted energy storage system considering the battery heat loss can be represented as:

[0100]

[0101] where t represents any charging time, T represents the number of unit time divided in a day; P t g P is the actual consumed power of the distribution network; P t ch P is the actual charging power of the vehicle-mounted energy storage system, expressed as the product of the open-circuit voltage U ocv of the battery and the battery charging current I bat .

[0102] The present application makes the following derivation and simplification to η b , and obtains the relationship between the actual charging power P t ch .

[0103]

[0104] The required power of the electric bus charging station in S3 per day is determined by the bus schedule, which can be expressed as

[0105]

[0106] The required power per day is determined by the bus schedule and the length of the line, and the energy conversion efficiency η of the charging station within a single day can be expressed as:

[0107]

[0108] where C ostg is the actual power consumption of the charging station in a day.

[0109] According to equation (11), the charging station energy conversion efficiency is the highest, which is equivalent to finding the minimum actual power consumption, so it is equivalent to taking the minimum actual power consumption of the charging station in a day as the objective function under the premise of considering the charging energy conversion efficiency.

[0110] In order to reflect the influence of the bus fast-charging station ordered charging method considering battery heating loss, this case compares four different scenarios:

[0111] Scenario one: without any scheduling strategy, the bus charges as soon as it arrives at the station;

[0112] Scenario two: ordered charging with the least power consumption as the target, the objective function is:

[0113]

[0114] where T represents the number of unit time divided in a day; Δt is the unit time, in this paper Δt = 60s; J is the total number of vehicles served by the bus charging station; Pt ch Pj(t) is the actual charging power of the energy storage system of the jth vehicle at time t.

[0115] Scenario three: the objective function is to minimize the daily operating cost of the charging station, and the battery energy conversion efficiency during the charging process of the electric bus is considered:

[0116]

[0117] where c(t) is the commercial electricity price of the charging station at time t.

[0118] Scenario four: the objective function is to minimize the daily operating cost of the charging station, and the battery energy conversion efficiency during the charging process of the electric bus is not considered, in which case P g t t ch The objective function is:

[0119]

[0120] The constraints required to establish the above optimization problem are as follows:

[0121] S3.1 Time constraints: Equation (14) indicates that the bus cannot be charged when it is not at the charging station; Equation (15) indicates that all vehicles cannot be charged when the charging station stops operating;

[0122]

[0123]

[0124] where d j，t is the charging state of vehicle j at time t, d j，t ∈{0,1}, d j，t =1 indicates that the vehicle is in a charging state, otherwise it is in a non-charging state; is the set of times when the jth bus is not at the charging station, where t is the departure time of the kth round of vehicle j, l jk is the back time of the kth round of vehicle j, n j is the total number of rounds that vehicle j needs to circulate in a day; T close is the time when the charging station is closed.

[0125] S3.2 Charging station equipment constraints: Equation (16) specifies that the number of charging piles simultaneously in charging is less than or equal to the total number of charging equipment N cs in the charging station; Equation (17) specifies that the maximum power of a single charging pile must not exceed the safe power P cs ​Formula (18) stipulates that the power distribution capacity of the entire charging station shall not exceed the maximum safe power P of the charging station's power distribution network. s ;

[0126]

[0127]

[0128]

[0129] S3.3 Constraints on travel demand:

[0130]

[0131]

[0132]

[0133] Formula (19) means that the SOC of each vehicle at the start of each cycle should be between the ratio of the energy required for a single trip to the maximum energy plus the minimum SOC limit of the protection battery. low and the set maximum SOC value sox max Between; Formula (20) represents the time when vehicle j departs for the kth time. The formula for calculating the State of Charge (SOC) of a vehicle at that time. The SOC of a vehicle at any given time is the SOC at the beginning of the day plus the amount of electricity charged into the vehicle during the charging activities that occurred before that time, minus the amount of electricity consumed during the previous trips; Formula (21) means that the amount of electricity charged in a day can meet the total amount of electricity required for a day's trips, thus ensuring the cyclicality of the charging strategy.

[0134]

[0135]

[0136] In the formula, y j，t and z j，t y is the decision variable for controlling the start and end of continuous charging during the charging process of vehicle j after returning to the station. j，t , z j，t ∈{0,1}; This refers to the collection of time periods that vehicle j spends within the charging station after returning to the station. Formulas (22) to (23) ensure that when the charging strategy in this paper is adopted, the charging behavior of each bus is continuous in time during the charging process.

[0137] Since the established battery efficiency model embodies nonlinear characteristics, the optimization objectives (11) and (12) established in S3 are nonlinear optimization, and the present application uses piecewise linearization for processing, and the formula for piecewise linearization is:

[0138]

[0139]

[0140]

[0141]

[0142] In the formula, is an auxiliary constraint parameter, and subscript x corresponds to the xth segment after linearization, represents that the charging power is located in the xth segment of the broken line segment after piecewise linearization, and the value is and are the upper and lower limit values of the xth segment of the segmented interval power P li，x ; K η，x and B η，x are linearization coefficients, reflecting the influence of the charging power ; W x ={1, 2, 3}.

[0143] Further, the optimization objective obtained in the previous step is a linearization model, and solving the model obtains the optimal charging plan, including the optimal charging time of each vehicle and the corresponding charging power P t ch and the corresponding P t g . This case compares four scenarios, and the results show that the power consumption of scenario two is reduced compared to scenario one, and the cost of scenario three is lower than that of scenario four. Through the comparison results, it can be known that the ordered charging method of the bus fast charging station considering the dynamic charging loss of the battery can reduce the power consumption, improve the charging energy conversion efficiency, reduce the heat loss of the battery and prolong the service life of the battery, at the same time, reduce the charging cost of the electric bus and improve the economy.

[0144] The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

[0145] Finally, it should be noted that the above only describes the preferred examples of the present application, and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that modifications can be made to the technical solutions described in the foregoing embodiments, or some of the technical features thereof can be replaced equivalently, without departing from the spirit and principle of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for orderly charging of buses at fast charging stations considering dynamic charging losses of batteries, characterized in that, Includes the following steps: S1. Based on the charging station's operating time, equipment power limitations, quantity limitations, and bus departure schedule, establish a charging demand model for electric buses to determine the electricity demand required to meet the operation of bus routes. S2. Based on the first-order RC circuit model, establish the battery heat loss model and the relationship between charging energy conversion efficiency and the actual charging power of the on-board energy storage system; S2 includes the following steps: S2.1 Establishing a battery efficiency model: First, establish the equivalent circuit model of the battery. The battery charging process is constant current charging, and the charging current is... The polarization capacitance remains unchanged. Since no current flows through it, this model is represented by formula (3): ； In the formula, This refers to the terminal voltage of the lithium battery. This is the open-circuit voltage of the battery; This is the charging current; The internal resistance of the battery is in ohms. This refers to the battery's polarization internal resistance. Energy loss during the full charging process of an electric bus battery Represented as: ； In the formula Battery charging time on a single charge For battery polarization capacitors, This is the voltage across the polarization capacitor; Charging energy loss power This is represented as charging energy loss. Regarding time The derivative, ； Energy conversion efficiency of electric bus battery charging at any given time Represented as: ； In the formula This refers to the terminal voltage of the lithium battery. The current is the battery charging current. The internal resistance of the battery is in ohms. This refers to the battery's polarization internal resistance. Energy loss during battery charging; S2.2 The relationship between the charging energy conversion efficiency considering battery heat loss and the actual charging power supplied by the on-board energy storage system is expressed as follows: ； In the formula, Represents any charging moment. Represents the number of time units divided into a day; This represents the actual power consumed by the power distribution network. The actual charging power supplied to the on-board energy storage system is expressed as the battery's open-circuit voltage. and battery charging current The product; right The following derivation and simplification yields the actual charging power. Relationship: ； S3. The objective function is to minimize the actual electricity consumption of the charging station in a day or the actual electricity cost of the charging station in a day. The battery heat loss is taken into account. A nonlinear optimization objective function model is established with constraints such as the charging station operating time, the number of charging piles, the maximum power of the charging piles, the power distribution capacity, the electricity demand of electric buses, and the continuity of electric bus charging time. S4. Piecewise linearization is used to transform the nonlinear optimization objective function model in S3 programming into a mixed integer convex programming problem. Solving the mixed integer convex programming problem yields the optimal charging plan, including the optimal charging time and corresponding charging power for each vehicle.

2. The orderly charging method for bus fast charging stations considering dynamic battery charging losses according to claim 1, characterized in that, In the charging demand model for electric buses in S1, all buses have an onboard energy storage system whose state of charge before departure is sufficient to complete the entire route: ； ； In the formula, Number the vehicle; For vehicles The number of buses serving the routes; vehicles The first departure time, the last departure time, and the departure interval of the route. For vehicles The length of the operating line; For vehicles The number of times each bus on the service route needs to run repeatedly; For vehicles In the The start time of the next loop; For vehicles Energy consumption per unit kilometer of the serviced lines; For vehicles The maximum energy of the vehicle-mounted energy storage system; To account for additional losses caused by traffic conditions and ensure the safe operation of vehicles, the lower limit of the State of Charge (SOC) is set. Representative vehicle In the k SOC before the start of the next cycle.

3. The orderly charging method for bus fast charging stations considering dynamic battery charging losses according to claim 1, characterized in that, In S3, the objective function is to minimize the actual electricity consumption of the charging station in a day. ； In the formula, Represents the number of time units divided into a day; In this article, the unit of time is... The total number of vehicles serving bus charging stations; For the first The car is The actual charging power of the on-board energy storage system at any given time.

4. The orderly charging method for bus fast charging stations considering dynamic battery charging losses according to claim 1, characterized in that, In S3, the objective function is to minimize the actual electricity cost of the charging station throughout the day. ； For cities operating charging stations t Commercial electricity prices at any given time.

5. A method for orderly charging of a bus fast-charging station considering dynamic battery charging losses according to claim 4, characterized in that, The constraints on the objective function in S3 are as follows: S3.1 Time constraints: Equation (14) means that buses cannot be charged when they are not at a charging station; Equation (15) means that all vehicles cannot be charged when the charging station is closed. ； ； In the formula, For vehicles exist t The charging status at all times. The vehicle is in a charging state, otherwise it is in a non-charging state. Number The bus does not meet at the charging station at the designated time. ,in For vehicles j No. k The start time of each round, For vehicles j No. k The return time for each round, For vehicles j The total number of cycles that need to be repeated in a day; This refers to the time the charging station is closed. S3.2 Charging station equipment constraints: Formula (16) stipulates that the number of charging piles charging simultaneously is less than or equal to the total number of charging devices in the charging station. Formula (17) stipulates that the maximum power of a single charging pile shall not exceed the safe power. Formula (18) stipulates that the power distribution capacity of the entire charging station shall not exceed the maximum safe power of the charging station's power distribution network. ; ； ； ； S3.3 Constraints on travel demand: ； ； ； Formula (19) means that the SOC of each vehicle at the start time of each cycle should be between the ratio of the energy required for a single trip to the maximum energy plus the minimum SOC limit of the protection battery. and the set maximum SOC Between; Formula (20) represents vehicles j In the k Next departure time Vehicle SOC The vehicle's SOC at any given time is the SOC at the beginning of the day plus the amount of electricity charged into the vehicle during the charging activities that occurred before that time, minus the amount of electricity consumed during the previous trips; Formula (21) represents the sum of the electricity charged in a day to meet the daily travel needs, ensuring the cyclicality of the charging strategy. ； ； In the formula, and It is numbered j The decision variables for starting and ending continuous charging are controlled during the charging process after the vehicle returns to the station. For vehicles j Meet at the charging station within the designated time period after returning to the station. Formulas (22) to (23) ensure that the charging strategy of the present invention is adopted so that the charging behavior of each bus is continuous in time.

6. The orderly charging method for bus fast charging stations considering dynamic battery charging losses according to claim 1, characterized in that, The formula for piecewise linearization in S4 is: ； ； ； ； In the formula, Subscripts are used for auxiliary constraint parameters. x The corresponding linearized first x part, This indicates that the charging power is located at the th position of the piecewise linearized segment. x Segment, value and The first x Segmented interval power The upper and lower limits; and The linearization coefficient reflects the charging power. Impact .

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