A peak shaving and valley filling method for metro train power flow based on car-to-car communication technology

Abstract

The application discloses a subway train power flow peak shaving and filling method based on vehicle-to-vehicle communication technology, and is based on a traditional four-section single-vehicle energy-saving driving method; a coasting-uniform speed combined mode is adopted to effectively utilize an energy-saving slope and achieve the purpose of reducing energy consumption.In the case that a train has been sent a given power flow, a multi-vehicle cooperative optimization method for absorbing an actual power flow can absorb power of a power grid as much as possible to achieve the effect of reducing grid-side fluctuation peak shaving and filling.The application divides a wave peak and a wave valley into intervals, reduces the working condition conversion frequency of the train on the basis of absorbing power for as long as possible, and increases passenger comfort.The application changes a past train operation according to an offline optimized driving strategy to online optimization, and further improves the optimization efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of subway train power flow control, in particular to a peak shaving and valley filling method for subway train power flow based on train-to-train communication technology. BACKGROUND

[0002] The prior art usually adopts the method of "cruise-coast" group to optimize the single train curve in the case of known front car speed curve, and according to the time of the front car braking curve, a secondary traction is inserted on the basis of single train optimization to maximize the absorption of regenerative braking energy. At the same time, further energy saving optimization is carried out through traction, braking transmission efficiency. But the prior art only optimizes the energy-saving train timetable or train control strategy through an offline process, which has defects in effectively and timely responding to disturbances or delays in real-time train operation, and is aimed at the scene of front car braking and the increase of secondary traction of the car, which is only the coincidence of time, and may appear over-absorption. The optimization of interval running time and stop time is not considered, the constraint amount is large, the absorption of braking energy of a train is considered, and the influence of power of other trains in the same power supply section is not considered, so that the existing single train curve optimization scheme cannot realize the peak shaving and valley filling of power flow. SUMMARY

[0003] In view of the above problems in the prior art, the peak shaving and valley filling method for subway train power flow based on train-to-train communication technology provided by the present application solves the problem that the existing single train curve optimization scheme cannot realize the peak shaving and valley filling of power flow.

[0004] In order to achieve the above-mentioned application purposes, the technical scheme adopted by the present application is as follows:

[0005] A peak shaving and valley filling method for subway train power flow based on train-to-train communication technology is provided, which comprises the following steps:

[0006] S1, obtaining line data and vehicle data; the vehicle data includes the power of each train that has been sent out;

[0007] S2, initializing the speed at the end of maximum traction of the train, the actual running time of the train, the control strategy and the optimized power time period;

[0008] S3, judging whether the current interval running time is greater than the sum of the original planned running time of the train and the running time variation range of the train, if yes, entering step S10; otherwise, entering step S4;

[0009] S4, obtaining the maximum braking section time and the position of starting maximum braking according to the speed limit obtained by reverse calculation from the terminal braking;

[0010] S5, obtaining the time and position of the end of traction according to the speed from the start point traction to the end of traction;

[0011] S6, judging whether there is a peak of power exceeding the original power wave in the time domain if the train travels to the maximum traction end time, if yes, entering step S11; otherwise, entering step S7;

[0012] S7, obtaining the scheme with the minimum reduced energy consumption and eliminated power ratio corresponding to the actual running time of the current train by dividing the time interval and gradually reducing the optimized power;

[0013] S8, increasing the speed at the maximum traction end time of the train;

[0014] S9, judging whether the speed at the maximum traction end time of the current train is greater than the train speed limit, if yes, entering step S11; otherwise, returning to step S5;

[0015] S10, selecting the scheme with the minimum reduced energy consumption and eliminated power ratio from the schemes corresponding to the actual running time of the different trains as the optimal train control scheme, and completing the peak shaving and valley filling of the metro train power flow;

[0016] S11, increasing the actual running time of the train, resetting the speed at the maximum traction end time to the minimum safe cruising speed and returning to step S3.

[0017] Further, the specific method of step S2 is:

[0018] The speed at the traction end time of the train is initialized as the safe speed of the train cruising, the actual running time of the train is initialized as the original planned running time of the train minus the value of the train running time variation range, and the control strategy and the optimized power time period are initialized as empty.

[0019] Further, the specific method of step S7 includes the following sub-steps:

[0020] S7-1, obtaining the maximum power P max and the minimum power P min between the time T tr when the train travels to the maximum traction end time and the actual running time T of the train minus the time ΔT br when the train starts maximum braking to parking; setting the initial value P opt of the optimized power as P max , and initializing the current interval number m as 1;

[0021] S7-2, judging whether P opt is greater than P min , if yes, entering step S7-3; otherwise, entering step S8;

[0022] S7-3, making P optAnd a line parallel to the time axis, recording the points [t1, t2, ..., t] where this line intersects the original power curve. 2n-1 ,t 2n ];

[0023] S7-4. Divide the time interval into n time intervals, such that the starting time of the m-th time interval is t. 2m-1 The end time is t 2m ;

[0024] S7-5. Determine if the current m is less than n. If so, proceed to step S7-6. Otherwise, select the scheme with the smallest ratio of energy consumption reduction to power elimination in different intervals of the same optimized power value from the temporary schemes, save it, reduce the current optimized power value, and return to step S7-2. The scheme with the smallest ratio of energy consumption reduction to power elimination includes the speed of the train at the end of the maximum traction, the coasting start point, the start and end times of the first time interval, the actual running time of the train, and the corresponding energy consumption value.

[0025] S7-6, [t] 2m-1 ,t 2m P in the time interval opt The above power is absorbed; the remaining time intervals are optimized using a single-vehicle driving strategy, and the current optimized solution is temporarily stored;

[0026] S7-7. Increment the value of m by 1 and return to step S7-5.

[0027] Furthermore, the specific method for optimizing the remaining time intervals using a single-vehicle driving strategy includes the following sub-steps:

[0028] A1. If the current slope is downhill, coasting is used; if the current slope is uphill, constant speed is used. If the speed limit or safe speed is reached while coasting, constant speed is used, and the intersection of the current speed curve and the maximum braking curve is updated to the position X where the train begins maximum braking. br ;

[0029] A2. Determine whether the current train's running time is greater than the current actual train running time T. If yes, proceed to step A3; otherwise, proceed to step S8.

[0030] A3. Use the binary search method to insert lazy entries and initialize the lazy entry point X. co The position X where the train's maximum traction ends tr X, the position where the train begins maximum braking br The midpoint;

[0031] A4. When the train reaches the coasting start point X coAdopting the coasting, and updating the intersection point of the current corresponding speed curve and the maximum braking curve as the position X where the train starts the maximum braking br ;

[0032] A5, judging whether the absolute value of the difference between the current train running time and the actual train running time T is less than a time threshold value, if yes, recording the current running scheme and entering step S8; otherwise, entering step A6;

[0033] A6, if the current train running time is greater than the actual train running time T, taking the midpoint between the position where the current train starts the maximum braking and the current coasting starting point as the new coasting starting point; if the current train running time is greater than the actual train running time T, taking the midpoint between the position where the train maximum traction ends and the current coasting starting point as the new coasting starting point.

[0034] Further, the step length of the actual train running time adjusted each time is 1 second; the step length of the speed at the position where the train maximum traction ends adjusted each time is 1 kilometer per hour.

[0035] Further, the specific method for saving the scheme with the minimum reduced energy consumption and eliminated power ratio is:

[0036] According to the formula:

[0037]

[0038] Obtain the reduced energy consumption and eliminated power ratio E of the ith scheme i , and select the scheme with the minimum reduced energy consumption and eliminated power ratio to be saved; wherein E ori is the original energy consumption in the time domain; is the energy consumption value of the ith scheme; is the power of the ith scheme.

[0039] Further, the specific method for absorbing the power is:

[0040] If it is a power valley, power absorption is performed by adding traction; if it is a peak, power absorption is performed by adding braking.

[0041] Further, the reduced step length of the optimized power is 1% of the current optimized power.

[0042] The beneficial effects of the present application are: the present application is based on the traditional four-section energy-saving driving method of the train, and the coasting-uniform speed combination mode can effectively utilize the energy-saving slope to achieve the purpose of reducing energy consumption. In the case of knowing that the train has issued a certain power flow, the multi-train cooperative optimization method of the present application can absorb the power of the power grid as much as possible to achieve the effect of reducing the fluctuation of the grid side and cutting the peak and filling the valley. The present application divides the peak and valley into intervals, reduces the working condition conversion frequency of the train on the basis of absorbing power for as long as possible, and increases the passenger comfort. The present application changes the past driving strategy of the train according to the offline optimization to online optimization, and further improves the optimization efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a flowchart of the present method;

[0044] Figure 2 is a calculation diagram of the maximum traction section and the maximum braking section;

[0045] Figure 3 is a power partition interval diagram;

[0046] Figure 4 is a single train energy-saving driving strategy diagram;

[0047] Figure 5 is a single train insertion coasting diagram;

[0048] Figure 6 is a power screening diagram in the single train peak shaving and valley filling strategy;

[0049] Figure 7 is a speed screening diagram in the single train peak shaving and valley filling strategy. DETAILED DESCRIPTION

[0050] The specific embodiments of the present application are described below to facilitate those skilled in the art to understand the present application, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the present application defined and determined by the appended claims, and all inventions utilizing the concept of the present application are within the scope of protection.

[0051] As shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 , the peak shaving and valley filling method of the subway train power flow based on the train-to-train communication technology includes the following steps:

[0052] S1, obtaining line data and vehicle data; the vehicle data includes the respective power of the train that has been sent out, which can be obtained through train-to-train communication technology;

[0053] S2, initializing the speed at the end of the maximum traction of the train, the actual running time of the train, the control strategy and the optimized power time period;

[0054] S3, judging whether the current interval running time is greater than the sum of the original planned running time of the train and the running time variation range of the train, if yes, entering step S10; otherwise, entering step S4;

[0055] S4, obtaining the maximum braking section time and the position of starting maximum braking according to the end-point braking back calculation to the speed limit;

[0056] S5, obtaining the time and position of the end of traction according to the speed from the start-point traction to the end of traction;

[0057] S6, judging whether there is a power exceeding the peak value of the original power wave in the time domain in the time of the train traveling to the end of the maximum traction, if yes, entering step S11; otherwise, entering step S7;

[0058] S7, obtaining the scheme corresponding to the actual running time of the current train that reduces the energy consumption and eliminates the power ratio minimum through the way of dividing the time interval and gradually reducing the optimized power;

[0059] S8, increasing the speed at the end of the maximum traction of the train;

[0060] S9, judging whether the speed at the end of the maximum traction of the current train is greater than the train speed limit, if yes, entering step S11; otherwise, returning to step S5;

[0061] S10, selecting the scheme corresponding to the actual running time of the different trains that reduces the energy consumption and eliminates the power ratio minimum from the current obtained scheme as the optimal train control scheme, and completing the peak shaving and valley filling of the power flow of the subway train;

[0062] S11, increasing the actual running time of the train, resetting the speed at the end of the maximum traction stage to the minimum safe cruising speed and returning to step S3.

[0063] The specific method of step S2 is: initializing the speed at the end of the train traction to the safe speed of the train cruising, initializing the actual running time of the train to the value of the original planned running time of the train minus the running time variation range of the train, and initializing the control strategy and the optimized power time period to be empty.

[0064] The specific method of step S7 includes the following sub-steps:

[0065] S7-1, obtaining the time T trThe actual train running time T minus the time from the start of maximum braking to a complete stop ΔT br The maximum power P between max and minimum power P min ; Optimize the initial value P of the power opt Set to P max Initialize the current interval number m to 1;

[0066] S7-2, Determine P opt Is it greater than P? min If yes, proceed to step S7-3; otherwise, proceed to step S8.

[0067] S7-3, P has been done opt And a line parallel to the time axis, recording the points [t1, t2, ..., t] where this line intersects the original power curve. 2n-1 ,t 2n ];

[0068] S7-4. Divide the time interval into n time intervals, such that the starting time of the m-th time interval is t. 2m-1 The end time is t 2m ;

[0069] S7-5. Determine if the current m is less than n. If so, proceed to step S7-6. Otherwise, select the scheme with the smallest ratio of energy consumption reduction to power elimination in different intervals of the same optimized power value from the temporary schemes, save it, reduce the current optimized power value, and return to step S7-2. The scheme with the smallest ratio of energy consumption reduction to power elimination includes the speed of the train at the end of the maximum traction, the coasting start point, the start and end times of the first time interval, the actual running time of the train, and the corresponding energy consumption value.

[0070] S7-6, [t] 2m-1 ,t 2m P in the time interval opt The above power is absorbed; the remaining time intervals are optimized using a single-vehicle driving strategy, and the current optimized solution is temporarily stored;

[0071] S7-7. Increment the value of m by 1 and return to step S7-5.

[0072] The specific methods for optimizing the remaining time intervals using a single-vehicle driving strategy include the following sub-steps:

[0073] A1. If the current slope is downhill, coasting is used; if the current slope is uphill, constant speed is used. If the speed limit or safe speed is reached while coasting, constant speed is used, and the intersection of the current speed curve and the maximum braking curve is updated to the position X where the train begins maximum braking. br ;

[0074] A2. Determine whether the current train's running time is greater than the current actual train running time T. If yes, proceed to step A3; otherwise, proceed to step S8.

[0075] A3. Use the binary search method to insert lazy entries and initialize the lazy entry point X. co The position X where the train's maximum traction ends tr X, the position where the train begins maximum braking br The midpoint;

[0076] A4. When the train reaches the coasting start point X co Coasting is employed, and the intersection of the current speed curve and the maximum braking curve is updated to the position X where the train begins maximum braking. br ;

[0077] A5. Determine whether the absolute value of the difference between the current train's running time and the actual train running time T is less than the time threshold. If yes, record the current running plan and proceed to step S8; otherwise, proceed to step A6.

[0078] A6. If the current train's running time is greater than the actual train running time T, then the midpoint between the current train's maximum braking position and the current coasting start point shall be taken as the new coasting start point; if the current train's running time is greater than the actual train running time T, then the midpoint between the train's maximum traction end position and the current coasting start point shall be taken as the new coasting start point.

[0079] The actual running time of the train is adjusted in increments of 1 second each time; the speed of the train at the end of maximum traction is adjusted in increments of 1 kilometer per hour each time.

[0080] The specific method for preserving the scheme that minimizes energy consumption and eliminates power is as follows: According to the formula:

[0081]

[0082] Obtain the energy reduction to power elimination ratio E of the i-th scheme. i And select the scheme with the smallest ratio of reducing energy consumption to eliminating power to retain; where E ori This represents the original energy consumption within the time domain. Let be the energy consumption value of the i-th scheme; Let be the power of the i-th scheme.

[0083] The specific methods for absorbing power are as follows: if it is a power trough, then power absorption is achieved by adding traction; if it is a peak, then power absorption is achieved by adding braking.

[0084] The step size for reducing the optimized power is 1% of the current optimized power.

[0085] In summary, the application uses the car-car communication technology, and adjusts the operation time and operation strategy of the train to be issued in view of the total power flow of all trains known in the power supply area, so as to stabilize the grid side voltage. The application models the power flow under a power supply section, sets an evaluation system, selects a time period for each train, absorbs the known power, and achieves the purpose of peak shaving and valley filling of the grid side power.

Claims

1. A method for peak shaving and valley filling of metro train power flow based on car-to-car communication technology, characterized in that, The method comprises the following steps: S1, obtaining line data and vehicle data; the vehicle data comprises respective power of the trains that have been dispatched; S2, initializing a speed at a maximum traction end of the train, an actual running time of the train, a control strategy, and an optimized power time period; S3, judging whether a current interval running time is greater than a sum of a train original planned running time and a train running time variation range, if yes, entering step S10; Otherwise, entering step S4; S4, obtaining a maximum braking section time and a position of starting maximum braking according to a terminal braking back calculation to a speed limit; S5, obtaining a time and a position of the traction end according to a speed from a starting point traction to the traction end; S6, judging whether there is a power exceeding a peak value of an original power wave in a time domain in a time of the train traveling to the maximum traction end, if yes, entering step S11; Otherwise, entering step S7; S7, obtaining a scheme of reducing energy consumption and eliminating power ratio minimum corresponding to the actual running time of the current train by dividing time interval and gradually reducing the optimized power in a manner; S8, increasing the speed at the maximum traction end of the train; S9, judging whether the speed at the maximum traction end of the current train is greater than a train speed limit, if yes, entering step S11; Otherwise, returning to step S5; S10, selecting a scheme of reducing energy consumption and eliminating power ratio minimum from schemes corresponding to different actual running times of the current trains as an optimal train control scheme to complete peak shaving and valley filling of the metro train power flow; S11, increasing the actual running time of the train, resetting the speed at the maximum traction end time to a minimum safe cruising speed, and returning to step S3.

2. The method of claim 1, wherein, The specific method of step S2 is: The speed at the traction end of the train is initialized as a safe speed of the train cruising, the actual running time of the train is initialized as a value of the train original planned running time minus the train running time variation range, and the control strategy and the optimized power time period are initialized as empty.

3. The method of claim 1, wherein, The specific method of step S7 comprises the following sub-steps: S7-1, acquiring a time T when the train travels to the end of maximum traction tr between the actual running time T of the train and the time ΔT when the train starts maximum braking to stop br maximum power P max and minimum power P min ; set the initial value P opt of the optimized power to P max , and initialize the current interval number m to 1; S7-2, judge P opt whether greater than P min if yes, go to step S7-3; otherwise, go to step S8; S7-3, P opt and the line parallel to the time axis, record the point [t1, t2,..., t 2n-1 2n ] that the line intersects with the original power curve.​ S7-4, divide n time intervals, the start time of the mth time interval is t 2m-1 , the end time is t 2m ; S7-5, judging whether the current m is less than n, if yes, entering step S7-6; otherwise, selecting a scheme of reducing energy consumption and eliminating power ratio minimum in different intervals in the same optimized power value from the temporary storage scheme for saving, and reducing the value of the current optimized power, and returning to step S7-2; The scheme of reducing energy consumption and eliminating power ratio minimum comprises a speed at the maximum traction end of the train, a coasting start point, a start time and an end time of the first time interval, the actual running time of the train, and a corresponding energy consumption value; S7-6, the [t 2m-1 ,t 2m ] time interval P opt The above power is absorbed; the remaining time interval is optimized by using the single-vehicle driving strategy, and the current optimized scheme is temporarily stored. S7-7, adding 1 to the value of m and returning to step S7-5.

4. The method of claim 3, wherein, The specific method of optimizing the remaining time intervals by using the single train driving strategy comprises the following sub-steps: A1, if the current is downhill, then adopt the coasting; if the current is uphill, then adopt the uniform speed; wherein, if the coasting reaches the speed limit or safety speed, then adopt the uniform speed, and update the intersection of the current corresponding speed curve and the maximum braking curve to the position X where the train starts maximum braking br ; A2, judging whether the running time of the current train is greater than the actual running time T of the train, if yes, entering step A3; otherwise, entering step S8; A3, initialize the start point X of the lazy line by dichotomy co the midpoint of the position X where the maximum braking of the train begins tr the midpoint of the position X where the maximum braking of the train begins br the midpoint of the position X where the maximum braking of the train begins A4、When the train runs to the start point X of the coasting, the coasting is adopted, and the intersection point of the current corresponding speed curve and the maximum braking curve is updated to the position X where the train starts the maximum braking co A4、When the train runs to the start point X of the coasting, the coasting is adopted, and the intersection point of the current corresponding speed curve and the maximum braking curve is updated to the position X where the train starts the maximum braking br A4、When the train runs to A5, judging whether an absolute value of a difference between the running time of the current train and the actual running time T of the train is less than a time threshold, if yes, recording a current running scheme and entering step S8; otherwise, entering step A6; A6, increasing the actual running time of the train, and returning to step A2. A6、If the running time of the current train is greater than the actual running time T of the train, the midpoint between the position where the current train starts maximum braking and the current coasting starting point is taken as the new coasting starting point; if the running time of the current train is greater than the actual running time T of the train, the midpoint between the position where the maximum traction of the train ends and the current coasting starting point is taken as the new coasting starting point.

5. The method of claim 1, wherein, The step length of the actual running time of the train is 1 second each time; the step length of the speed at the end of the maximum traction of the train is 1 km / h each time.

6. The method of claim 3, wherein, The specific method for saving the scheme with the minimum ratio of energy consumption reduction to power elimination is: According to the formula: obtaining the reduced energy consumption and eliminated power ratio E of the ith scheme i and selecting the scheme with the minimum reduced energy consumption and eliminated power ratio E for reservation; wherein E ori is the original energy consumption in the time domain; is the energy consumption value of the ith scheme; is the power of the ith scheme.

7. The method of claim 3, wherein, The specific method for absorbing power is: If it is a power valley, power absorption is carried out by adding traction; if it is a peak, power absorption is carried out by adding braking.

8. The method of claim 3, wherein, The reduction step length of the optimized power is 1% of the current optimized power.

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