Bidirectional converter energy cooperative control method and control system

Abstract

The invention provides a bidirectional converter energy cooperative control method and system, relates to the technical field of urban rails, is applied to a bidirectional converter in an urban rail transit traction power supply system, and comprises the steps of determining partitions of a regulation and control station according to a preset partition strategy, wherein the preset partition strategy is used for performing partition management by taking a selected regulation and control transformer substation as a center and taking two regulation and control transformer substations before and after as cooperative control stations as a partition; determining all trains and all substations belonging to the subarea based on the control range of the subarea; according to the power parameters of the trains in the partitions and the power parameters of the substations in the partitions, power interaction parameters between the trains are obtained; obtaining a plurality of voltage judgment results based on a plurality of preset voltage judgment conditions; and dynamically adjusting the droop slope and the starting voltage of the bidirectional converter in combination with the plurality of voltage judgment results and the interaction parameters of the inter-train power to realize cooperative control of the bidirectional converter.

Description

Technical Field

[0001] The present invention relates to the field of urban rail technology, and in particular to an energy cooperative control method and control system for a bidirectional converter. Background Art

[0002] With the rapid expansion of urban rail transit networks, their operating mileage has increased significantly, placing higher demands on energy efficiency and operation management. As a key component, the urban rail transit traction power supply system traditionally relies on rectifier units to achieve the conversion of AC to DC to support the traction needs of trains. However, due to the lack of controllability of the output voltage external characteristics of such rectifier units, the system energy distribution is passively dependent on the real-time position and power demand of the train, limiting the space for energy efficiency optimization.

[0003] To solve this problem, bidirectional converters have gradually become the preferred solution for upgrading urban rail traction power supply systems due to their advantages of bidirectional energy flow, controllable DC voltage regulation, and high power factor. The application of bidirectional converters can theoretically significantly improve the flexibility and efficiency of energy management, especially in terms of energy recovery and reuse during train traction and braking.

[0004] However, in practical applications, traction substations based on bidirectional converters face a complex and changeable operating environment, including the coordinated operation of multiple trains and real-time energy exchange of the entire system, which makes the efficient use of traction and braking energy subject to multiple factors, such as substation voltage characteristics, dynamic power requirements of trains, position changes, and rail potential. In order to achieve active energy saving, that is, to optimize the system flow by accurately regulating the voltage of the bidirectional converter in the traction substation, it is crucial to ensure the accuracy of the control instructions, otherwise it may be counterproductive and reduce the overall energy utilization efficiency.

[0005] At present, when promoting bidirectional converters, urban rail transit generally adopts a conservative strategy of "one rectifier unit + one bidirectional converter unit" (1+1 configuration mode) to ensure the stability of the power supply system. However, this configuration mode brings new challenges: due to the fluctuation of the AC voltage of each traction substation, the no-load voltage of the rectifier unit also fluctuates, which in turn limits the freedom of parameter regulation of the bidirectional converter. The traditional fixed droop slope and starting voltage settings are no longer applicable, which may cause circulation problems between the rectifier unit and the bidirectional converter in the same station, affecting the stable operation of the system.

[0006] Therefore, in the 1+1 configuration mode, the control strategy of the bidirectional converter needs to consider the matching between the rectifier units and the bidirectional converter units in the station, as well as the coordinated operation between the bidirectional converter units and the bidirectional converter units in the entire line. This requires the control strategy to have a high degree of dynamic adaptability and global optimization capabilities.

[0007] Therefore, it is necessary to provide a bidirectional converter energy coordinated control method and control system to solve the above technical problems. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a bidirectional converter energy collaborative control method and control system, which realizes the dynamic regulation of the voltage characteristics of the bidirectional converter in the substations of the whole line through an integrated energy management system. This solution not only perfectly adapts to the current mainstream 1+1 configuration mode, but also shows stronger environmental adaptability and energy efficiency optimization capabilities compared to the traditional control method using a fixed droop slope and starting voltage, effectively reduces the power transmission loss, suppresses the fluctuation of the train input voltage, and helps to reduce the rail potential, providing strong technical support for the sustainable development of urban rail transit systems.

[0009] The present invention provides a method for energy cooperative control of a bidirectional converter device, which is applied to a bidirectional converter device in a traction power supply system of urban rail transit. The method comprises the following steps:

[0010] Determine the partition of the control station according to a preset partition strategy, wherein the preset partition strategy is to manage the partition as a partition with the selected control substation as the center and the two control substations before and after it as the collaborative control station;

[0011] Determine all trains and all substations belonging to the partition based on the control range of the partition;

[0012] Acquiring an interaction parameter of power between trains according to power parameters of trains in the zone and power parameters of substations in the zone;

[0013] Acquire multiple voltage judgment results based on multiple preset voltage judgment conditions, wherein the multiple voltage judgment conditions include judging whether the maximum value of the rail potential acquired is less than the limit value, whether the rectifier starting voltage of the bidirectional converter is less than the no-load voltage of the rectifier unit, and whether the voltage adjustment range of the bidirectional converter exceeds the limit range;

[0014] The droop slope and starting voltage of the bidirectional converter are dynamically adjusted in combination with the multiple voltage judgment results and the interaction parameters of the power between trains to achieve coordinated control of the bidirectional converter.

[0015] Preferably, the preset partitioning strategy also includes:

[0016] For the two control substations at the front end of the line, the existing control substation in front and the two control substations behind are selected as the sub-area, and for the two control substations at the end of the line, the two control substations in front and the existing control substation behind are selected as the sub-area.

[0017] Preferably, the method for determining a train in a zone includes:

[0018] Determine the distance between the first and last control substations in the zone and the departure station, collect the location information of each train, compare the train location information with the distance, and determine whether the train is in the zone.

[0019] Preferably, the method for obtaining the interaction parameters of power between trains includes:

[0020] Collect train power information within the zone to determine whether each train is in traction or braking state;

[0021] For each train, if its power is greater than zero, it is determined that the train is in traction state, and the traction power of the train is recorded; if the power is less than zero, it is determined that the train is in braking state, and the braking power of the train is recorded;

[0022] The traction power and braking power of all trains in the section are summed up respectively to obtain the total traction power and braking power in the section as the interaction parameters of the power between trains.

[0023] Preferably, the method for obtaining the power parameters of the substation includes:

[0024] Collect the voltage and current values ​​of the rectifier units of each traction substation in the zone and calculate the power of the rectifier units;

[0025] Collect the voltage and current values ​​of the bidirectional converters of each traction substation in the zone and calculate the power of the bidirectional converters;

[0026] The rectifier power and inverter power of each substation in the zone are summed up respectively to obtain the total rectifier power and inverter power in the zone.

[0027] Preferably, the method for obtaining multiple voltage judgment results based on the multiple voltage judgment conditions includes:

[0028] Real-time monitoring and acquisition of the maximum value of rail potential;

[0029] Check whether the rectifier starting voltage of the bidirectional converter is always higher than the no-load voltage of the rectifier unit;

[0030] Confirm whether the voltage regulation range of the bidirectional converter device remains between the preset maximum and minimum voltage limits;

[0031] When any voltage judgment condition is not met, the corresponding adjustment mechanism is triggered.

[0032] Preferably, the method further includes the step of setting the initial droop slope and the starting voltage of the bidirectional converter, specifically including:

[0033] The rectifier starting voltage V3 of the bidirectional converter is set based on the rated no-load voltage of the rectifier unit to ensure that V3 is greater than the no-load voltage of the rectifier unit;

[0034] The inverter starting voltage V6 is set based on the rectifier starting voltage V3 of the bidirectional converter to ensure that V6 is greater than V3, so as to prevent the circulation operation problem of the bidirectional converters between different stations;

[0035] After the initial setup is completed, the 35kV dynamic grid voltage on the AC side of the rectifier units at all stations along the entire line is monitored in real time, and the dynamic no-load voltage of the rectifier units is calculated to adapt to grid fluctuations and ensure stable system operation.

[0036] Preferably, the method for dynamically adjusting the droop slope and the starting voltage of the bidirectional converter device in combination with the multiple voltage judgment results and the train-to-train power interaction parameters includes:

[0037] Set the droop slope adjustment flag Flag and the starting voltage adjustment flag Logo of the bidirectional converter device;

[0038] Update the status of the flag bit according to the train power interaction situation and substation power situation in the section;

[0039] According to the state of the flag bit and the voltage judgment result, it is determined whether the droop slope and the starting voltage of the bidirectional converter need to be adjusted;

[0040] If adjustment is required, the droop slope, rectifier start voltage and inverter start voltage are adjusted incrementally or decrementally according to the preset step sizes k and h respectively;

[0041] When the train in the section is in both traction and braking state and full power interaction is not achieved, the droop slope of the bidirectional converter is increased, while the rectifier starting voltage is reduced and the inverter starting voltage is increased;

[0042] When the trains in the section fully realize power interaction or there is no need for power interaction between trains, the droop slope of the bidirectional converter is reduced, while the rectifier starting voltage is increased and the inverter starting voltage is reduced;

[0043] When the rail potential reaches or exceeds the limit value, the droop slope of the bidirectional converter is reduced, while the rectifier starting voltage is increased and the inverter starting voltage is reduced;

[0044] When the rectifier starting voltage of the bidirectional converter is lower than the no-load voltage of the rectifier unit, the rectifier starting voltage of the bidirectional converter is increased and the inverter starting voltage is reduced;

[0045] When the voltage droop range of the bidirectional converter exceeds the maximum or minimum voltage limit, the droop slope of the bidirectional converter is reduced, and the rectifier starting voltage is increased and the inverter starting voltage is reduced.

[0046] Preferably, the adjustment mechanism includes:

[0047] Rail potential over-limit adjustment mechanism: When the maximum rail potential reaches or exceeds the limit value, the droop slope of the bidirectional converter is automatically reduced, and the rectifier starting voltage and inverter starting voltage are adjusted accordingly;

[0048] Rectification start voltage is lower than no-load voltage adjustment mechanism: when the rectification start voltage of the bidirectional converter is lower than the no-load voltage of the rectifier unit, the rectification start voltage is automatically increased and the inverter start voltage is reduced;

[0049] Voltage droop range over-limit adjustment mechanism: When the voltage droop range of the bidirectional converter exceeds the maximum or minimum voltage limit, the droop slope is automatically reduced, and the rectifier starting voltage and inverter starting voltage are adjusted;

[0050] Dynamic response adjustment mechanism: Dynamically adjust the droop slope and starting voltage of the bidirectional converter according to the train power interaction within the section and the substation power situation.

[0051] The present invention also provides a bidirectional converter energy cooperative control system, which is used to execute the bidirectional converter energy cooperative control method, and is applied to a bidirectional converter in an urban rail transit traction power supply system. The system includes:

[0052] A partition management module, used to determine the partitions of the control station according to a preset partition strategy, wherein the preset partition strategy is to perform partition management with the selected control substation as the center and the two control substations before and after it as collaborative control stations as one partition;

[0053] An area identification module, used for determining all trains and all substations belonging to the zone based on the control range of the zone;

[0054] A power interaction analysis module, used for obtaining the interaction parameters of power between trains according to the power parameters of the trains in the zone and the power parameters of the substations in the zone;

[0055] A voltage judgment module is used to obtain multiple voltage judgment results based on multiple preset voltage judgment conditions, wherein the multiple voltage judgment conditions include judging whether the maximum value of the rail potential obtained is less than the limit value, whether the rectifier starting voltage of the bidirectional converter is less than the no-load voltage of the rectifier unit, and whether the voltage adjustment range of the bidirectional converter exceeds the limit range;

[0056] A dynamic adjustment module is used to dynamically adjust the droop slope and starting voltage of the bidirectional converter device in combination with the multiple voltage judgment results and the interaction parameters of the power between trains, so as to realize the coordinated control of the bidirectional converter device.

[0057] Compared with the related art, the energy cooperative control method and control system of a bidirectional converter provided by the present invention have the following beneficial effects:

[0058] The present invention determines the partition of the control station according to a preset partition strategy, wherein the preset partition strategy is to perform partition management with the selected control substation as the center and the two control substations before and after it as collaborative control stations as a partition; determine all trains and all substations belonging to the partition based on the control range of the partition; obtain the interaction parameters of the power between trains according to the power parameters of the trains in the partition and the power parameters of the substations in the partition; obtain multiple voltage judgment results based on multiple preset voltage judgment conditions, wherein the multiple voltage judgment conditions include judging whether the maximum value of the obtained rail potential is less than the limit value, whether the rectifier starting voltage of the bidirectional converter is less than the no-load voltage of the rectifier unit, and whether the voltage adjustment range of the bidirectional converter exceeds the limited range ; The droop slope and starting voltage of the bidirectional converter are dynamically adjusted in combination with the multiple voltage judgment results and the interactive parameters of the power between trains to realize the coordinated control of the bidirectional converter. Compared with the prior art, the present invention can adjust the droop slope and starting voltage of the bidirectional converter in real time according to the train operation status and substation power information in the 1+1 configuration mode, so as to realize the coordinated control of the bidirectional converters of the whole line. Compared with the control method using fixed droop slope and starting voltage, it is more adaptable. Compared with the method of only considering the configuration of bidirectional converters on the whole line, it better adapts to the current mainstream 1+1 configuration mode of bidirectional converters, so as to achieve the purpose of reducing power transmission loss, suppressing train input voltage fluctuation and reducing rail potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 The energy management system communication architecture diagram of the present invention;

[0060] Figure 2 It is a traction substation partition control strategy diagram of the present invention;

[0061] Figure 3 It is a bidirectional current conversion control strategy diagram of the present invention;

[0062] Figure 4 It is a configuration mode diagram of the bidirectional converter device of the present invention;

[0063] Figure 5 It is a flow chart of a method for coordinated energy control of a bidirectional converter device of the present invention;

[0064] Figure 6 It is a flow chart for realizing the energy cooperative control strategy of the full-line bidirectional converter device of the present invention;

[0065] Figure 7This is a module structure diagram of an energy cooperative control system of a bidirectional converter device of the present invention. DETAILED DESCRIPTION

[0066] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings. In addition, the embodiments of the present invention and the features in the embodiments may be combined with each other without conflict.

[0067] It should also be noted that, for ease of description, only the part relevant to the present invention but not all content is shown in the accompanying drawings. It should be mentioned before discussing exemplary embodiments in more detail that some exemplary embodiments are described as processing or methods depicted as flow charts. Although the flow chart describes each operation (or step) as sequential processing, many operations therein can be implemented in parallel, concurrently or simultaneously. In addition, the order of each operation can be rearranged. When its operation is completed, the processing can be terminated, but it can also have additional steps not included in the accompanying drawings. The processing can correspond to methods, functions, procedures, subroutines, subprograms, etc.

[0068] Embodiment 1

[0069] A bidirectional converter energy cooperative control method is applied to the bidirectional converter in the urban rail transit traction power supply system. Figure 6 As shown, the method comprises the following steps:

[0070] S1: Determine the partition of the control station according to a preset partition strategy, wherein the preset partition strategy is to perform partition management with the selected control substation as the center and the two control substations before and after it as collaborative control stations as one partition.

[0071] S2: Determine all trains and all substations within the zone based on the control scope of the zone.

[0072] S3: Obtaining the interaction parameters of power between trains according to the power parameters of the trains in the section and the power parameters of the substations in the section.

[0073] S4: Obtain multiple voltage judgment results based on multiple preset voltage judgment conditions, wherein the multiple voltage judgment conditions include judging whether the maximum value of the obtained rail potential is less than the limit value, whether the rectifier starting voltage of the bidirectional converter is less than the no-load voltage of the rectifier unit, and whether the voltage adjustment range of the bidirectional converter exceeds the limited range.

[0074] S5: Dynamically adjust the droop slope and starting voltage of the bidirectional converter device in combination with the multiple voltage judgment results and the interaction parameters of the power between trains to achieve coordinated control of the bidirectional converter device.

[0075] More specifically, a method for coordinated energy control of a bidirectional converter includes:

[0076] like Figure 1 The diagram shows the communication architecture of the energy management system. The energy management system can establish a communication loop between the train, the rectifier, the bidirectional converter and the energy management system, collect information such as the train, the rectifier, the bidirectional converter, and the rail potential through the communication module, and optimize the output voltage instruction of the bidirectional converter. The energy management system includes the energy management layer and the converter control layer: the energy management layer refers to the energy management system that collects and monitors the voltage and current data of the rectifier and the bidirectional converter in the substation in each substation in real time, and collects and monitors the power and position of the current train and the rail potential in real time, and then judges the power interaction of the train in the substation at the current moment, and then continuously adjusts the voltage characteristics of the bidirectional converter in the control station in the substation in real time to optimize the system flow; the converter control layer refers to the bidirectional converter that transmits the DC voltage and current data and AC voltage and current data collected by itself to the energy management layer on the one hand, and receives the control instruction of the energy management layer on the other hand. The bidirectional converter performs closed-loop control according to the control instruction to realize the opening and closing of the switch device, and finally achieves the purpose of energy regulation of the bidirectional converter of the entire line, and then achieves the goal of energy saving.

[0077] Among them, the data transmission between the energy management layer and the converter control layer is bidirectional and requires that the external communication port of the bidirectional converter device has a faster response from receiving the command to the execution of the internal control system, that is, the bidirectional converter device has a communication transmission channel for fast receiving and sending data to the outside, and the communication response time should be guaranteed within 50ms; at the same time, it is also required that the energy management layer itself sends and receives data and processes data within 50ms.

[0078] The data transmission between the energy management system and the rectifier unit is unidirectional, that is, the energy management system only collects voltage and current data related to the rectifier unit. In order to ensure the timeliness of the data collection related to the rectifier unit, it is necessary to install corresponding voltage and current sensors for data collection.

[0079] In the urban rail traction power supply system, the changes in train power and position are changing over time. In order to more accurately locate the train's position information and track the train's power changes, it is necessary to introduce the train's position information and power information for data monitoring and analysis. The data transmission between the energy management system and the train is one-way, that is, the energy management system only collects the position information, power information and rail potential information related to the train, and does not send any control commands to the train to ensure the safety of the train's operation; at the same time, the communication rate of the communication link also requires timeliness, and the communication response time should be guaranteed to be within 100ms.

[0080] Figure 2 The figure shows the traction substation zoning control strategy diagram. Since there are usually more than ten traction substations on the entire subway line, and the voltage characteristics of each substation will affect the energy flow in the nearby section, and the train status in the nearby section also needs to be used as a basis for real-time adjustment of the voltage characteristics of the substation. Therefore, when controlling the voltage of the bidirectional converter in the substation, it is necessary to manage the substation in zones: if the partition distance is too long, it will lead to additional line losses; if the partition distance is too short, the ability of workshop power interaction will be limited. Therefore, the way of dividing the area is very important when the substation is controlled in zones.

[0081] Taking the control substation as the center, the two stations before and after are coordinated control stations as a section for zoning management, which effectively prevents the extra line loss caused by too long distance and the limited power interaction between workshops caused by too short distance. When the control substation is the first two stations or the last two stations of the entire line, the control station does not meet the working conditions of the two stations before and after. Therefore, for the first two stations, the substation in front and the two substations behind are selected as the sub-section; for the last two stations, the two substations in front and the substation behind are selected as the sub-section.

[0082] After each substation selects a substation, it takes the substation as the center and judges the power interaction of the trains in the substation by analyzing the train operation status in the substation and the operation status of other substations, and then adjusts the voltage characteristics of the bidirectional converter in the substation.

[0083] Figure 3 The figure shows the control strategy diagram of the bidirectional converter. The energy coordination control strategy of the bidirectional converter of the whole line is implemented based on the control strategy of the single bidirectional converter as shown in the figure. The control strategy of the single bidirectional converter follows the control strategy in the patent "A bidirectional converter device and control method for high-altitude environment of subway", patent number CN114123838B, but it needs to be adjusted so that the current command in the rectifier direction is positive and the current command in the inverter direction is negative. At the same time, the rectifier droop slope V2-V3 and the inverter droop slope V6-V7 need to be associated to realize synchronous dynamic regulation.

[0084] In the urban rail traction power supply system based on the bidirectional converter, the starting voltage of the bidirectional converter determines the overall voltage level of the power supply system. The droop slope of the bidirectional converter affects the voltage rise and fall level of the traction network and the interaction of regenerative braking energy in the workshop. Therefore, the starting voltage and droop slope of the bidirectional converter have an important influence on the energy transfer of the system. Therefore, the control parameters of the bidirectional converter are selected as the droop slope, the rectifier starting voltage V3 and the inverter starting voltage V6. The specific control principles and control principles of the relevant parameters are as follows:

[0085] Control principle: The smaller the voltage droop slope of the bidirectional converter in the traction substation, the more conducive it is to stabilize the traction network voltage, to ensure that the train regenerative braking capacity is fully utilized, to suppress power transmission across sections, and to reduce rail potential; the larger the droop slope, the more conducive it is to power balance among substations, to regenerative braking energy workshop interaction, and to reduce the peak power of the bidirectional converter in the substation. The higher the starting voltage of the bidirectional converter in the traction substation, the more conducive it is to improve the voltage level of the traction network and reduce line losses; the lower the no-load voltage of the traction substation, the lower the train voltage when the train brakes, which is conducive to ensuring that the train regenerative braking capacity is fully utilized; therefore, the voltage characteristics of the traction substation based on the bidirectional converter will affect the regenerative braking energy transmission path, substation power distribution, rail potential, and line losses.

[0086] Control principle: When there are traction trains and braking trains in the section at the same time, on the one hand, the droop slope can be increased so that the regenerative braking energy is consumed by the traction train first, and the excess is then inverted back to the AC side through the bidirectional converter in the substation. When the slope increases to a certain value, the regenerative braking energy is fully utilized by the traction train in the section, and the train power is fully interactive. At this time, increasing the droop slope will not only fail to improve the utilization rate of the regenerative braking energy on the DC side, but will also increase unnecessary line losses; on the other hand, the rectifier starting voltage can be reduced and the inverter starting voltage can be increased, so that the regenerative braking energy can be consumed by the traction train first, but the range of the rectifier starting voltage reduction is limited by the no-load voltage of the rectifier unit and the voltage variation range. Increasing the workshop interaction energy and reducing the line loss are contradictory, but considering that the line loss accounts for a small proportion, it is given priority to increase the workshop interaction energy.

[0087] Therefore, when adjusting the voltage droop slope and starting voltage of the bidirectional converter device of the substation, it is necessary to make a real-time judgment on the power interaction of the trains in the section: if the section is composed of traction trains or braking trains and there is no demand for train power interaction, the droop slope should be as small as possible, the rectifier starting voltage should be as high as possible, and the inverter starting voltage should be as low as possible, which is conducive to the stability of the traction network voltage and the train energy is provided by the nearest substation, reducing line losses. At the same time, the rectifier starting voltage needs to be greater than the no-load voltage of the rectifier unit to prevent circulating current problems. If there are traction trains and braking trains in the section at the same time, there is a demand for train power interaction. At this time, the droop slope should be appropriately increased, the rectifier starting voltage should be appropriately reduced, and the inverter starting voltage should be appropriately increased to promote the priority interaction between regenerative braking energy and increase the utilization rate of the DC side of regenerative braking energy.

[0088] Figure 4 The figure shows the configuration mode of the bidirectional converter. At present, the configuration modes of the bidirectional converter in the urban rail transit traction power supply system are mainly divided into the following three types: the first is the 2+1 configuration mode, that is, a set of bidirectional converters is connected in parallel on the basis of the original two sets of rectifiers. This solution is reliable and easy to popularize, but it is only suitable for the initial promotion stage of the bidirectional converter because of its high investment cost and redundant capacity; the second is the 0+2 configuration mode, that is, the original two sets of rectifiers are completely replaced by two sets of bidirectional converters. This solution is the ultimate ideal solution for the application of bidirectional converters, but in order to meet V For Class I load requirements, the required capacity of the bidirectional converter is relatively large, the system reliability is slightly lower, and the bidirectional converter is still in the promotion stage at this stage, so this solution is less used; the third solution is the 1+1 configuration mode, that is, replacing one of the original rectifier units with a bidirectional converter. This solution is the most widely used and its reliability is guaranteed. However, in the coordinated control process of the bidirectional converter of the entire line, it is necessary to consider not only the operation matching mode of the bidirectional converter of this station and the rectifier unit, but also the operation matching mode between the bidirectional converters of the entire line and between the bidirectional converters of the entire line and the rectifier units.

[0089] Figure 5 This is a flow chart of the energy coordination control strategy of the bidirectional converter device applied to the traction power supply system of urban rail transit. In the process of the adaptive energy control strategy of the bidirectional converter device in the 1+1 configuration mode, the voltage adjustment range of the bidirectional converter device, the rail potential, and the no-load voltage of the rectifier unit are used as constraints. By adjusting the droop slope value of the bidirectional converter device of the entire line and the starting voltage value of the bidirectional converter device, the minimum energy consumption is achieved. The energy control principles of the traction substation partition control strategy are as follows:

[0090] ① Ensure that the regenerative braking energy is used first on the DC side, reducing the energy converted back to the AC side;

[0091] ② Ensure that the train voltage is below the mechanical brake start voltage threshold, so that the train can achieve 100% regenerative braking;

[0092] ③ The voltage of the traction network is kept at a high level. When there is no train power interaction demand, power transmission across sections is suppressed to reduce line losses;

[0093] ④ Ensure that the maximum absolute value of the rail potential does not exceed the limit value, the rectifier starting voltage of the bidirectional converter is less than the no-load voltage of the rectifier unit, and the voltage adjustment range of the bidirectional converter does not exceed the maximum or minimum voltage limit.

[0094] Figure 6 This is a flow chart for the energy collaborative control strategy of the bidirectional converters on the entire line. Each station monitors the status of the station and its nearby substations to determine the power interaction of nearby trains, and then adjusts the voltage characteristics of the bidirectional converters in the station. The implementation process of the energy collaborative control strategy of the bidirectional converters on the entire line is as follows:

[0095] Step 1: Set the initial droop slope and starting voltage of the bidirectional converter at each station: Set the rectifier starting voltage V3 of the bidirectional converter based on the rated no-load voltage of the rectifier unit. V3 needs to be greater than a certain value ΔU1 of the no-load voltage of the rectifier unit; set the inverter starting voltage V6 based on the rectifier starting voltage V3 of the bidirectional converter. V6 needs to be greater than a certain value ΔU2 of V3. At this time, the inverter starting voltage V6 must be greater than the no-load voltage of the rectifier unit. In this way, the circulation operation problem between the rectifier unit and the bidirectional converter can be effectively suppressed in the 1+1 configuration mode. At the same time, the setting of the shutdown voltage ΔU2 between V3 and V6 can also prevent the circulation operation problem of the bidirectional converters between different stations.

[0096] Step 2: The energy management system monitors the 35kV dynamic grid voltage on the AC side of the rectifier units at all stations along the entire line in real time, and calculates the dynamic no-load voltage of the rectifier units based on the collected 35kV grid voltage at each station;

[0097] The calculation formula of no-load voltage of rectifier unit is:

[0098] Among them, is the no-load voltage of the rectifier unit; is the 35kV grid voltage amplitude on the AC side of the rectifier unit; K is the transformer ratio of the rectifier unit;

[0099] Step 3: Determine the area for zone control with a substation as the center, and define the number of substations in the zone as n;

[0100] Step 4: Determine the number and number of trains running in the partition, and define the number of trains in the partition as m. The specific method is: first determine the distances xS1 and xSn between the first substation and the last substation in the partition and the departure station, and then collect the location information xTm of each train, and compare xTm with xS1 and xSn respectively. When xTm is within the range of xS1 and xSn, it means that the train is in the partition; on the contrary, when xTm is outside the range of xS1 and xSn, it means that the train is not in the partition.

[0101] Step 5: Collect the train power information PTm in the partition. If the power of the yth train is greater than 0, the train is working in the traction state, the traction power of the train PTrecy = PTy, and the braking power of the train PTinvy = 0; if the power is less than 0, the train is working in the braking state, the braking power of the station PTinvy = PTy, and the traction power of the train TPrecy = 0;

[0102] Step 6: Collect the voltage and current values ​​of the rectifier units of each traction substation in this partition, and calculate the power Prun of the rectifier units; collect the voltage and current of the bidirectional converter devices of each traction substation in this partition, and calculate the power Ptrn of the bidirectional converter devices; if the sum of the power of the rectifier units and the bidirectional converter devices of the x-th substation is greater than 0, the station is in the rectification state, the rectifier power Precx of the station is Prux+Ptrx, and the inverter power Pinvx of the station is 0; if the sum of the power is less than 0, the station is in the inverter state, the inverter power Pinvx of the station is Ptrx, and the rectifier power Precx of the station is 0;

[0103] Step 7: Sum the traction power and braking power of all trains in the partition: PTrecsum=PTrec1+…+PTrecm, PTinvsum=PTinv1+…+PTinvm; and sum the rectifier power and inverter power of all substations in the partition: Precsum=Prec1+…+Precn, Pinvsum=Pinv1+…+Pinvn;

[0104] Step 8: Set the droop slope adjustment flag Flag and the starting voltage adjustment flag Logo of the bidirectional converter. When all trains in the section are in traction state, that is, PTrecsum>0 and PTinvsum=0, and only when the power provided by each substation in the section is rectified power, that is, Precsum>0 and Pinvsum=0, it means that the trains in the section do not perform power exchange between the trains, and the flag Flag=0 and Logo=0; similarly, when all trains in the section are in braking state, that is, PTinvsum<0 and PTrecsum=0, and only when the power provided by each substation in the section is inverter power, that is, Pinvsum<0 and Precsum=0, it means that the trains in the section do not perform power exchange between the trains, and the flag Flag=0 and Logo=0;

[0105] Step 9: When the train in the section has both traction and braking states, that is, PTrecsum>0 and PTinvsum<0, it is necessary to judge the power provided by each substation in the section: When the traction power of the train in the section is greater than the braking power |PTrecsum|>|PTinvsum|, if and only if all substations in this section are in rectification state, that is, Precsum>0 and Pinvsum=0, it means that the train in the section has achieved full power interaction, and the flag Flag=0 and Logo=0. If all substations in this section are in both rectification state and inverter state, that is, Precsum>0 and Pinvsum<0, it means that The train in the section has not achieved full power interaction, and the flag is Flag=1 and Logo=1; similarly, when the traction power of the train in the section is less than the braking power |PTrecsum|<|PTinvsum|, if and only if all substations in this section are in the inverter state, that is, Pinvsum<0 and Precsum=0, it means that the train in the section has achieved full power interaction, and the flag is Flag=0 and Logo=0. If all substations in this section have both rectification and inverter states, that is, Precsum>0 and Pinvsum<0, it means that the train in the section has not achieved full power interaction, and the flag is Flag=1 and Logo=1. Other combined operating conditions of the train traction power PTrecsum and braking power PTinvsum in the section, and the rectification power Precsum and inverter power Pinvsum of the substation in the section are all regarded as abnormal judgment operating conditions, and all return to the beginning of the process.

[0106] Step Ten: Continuously monitor the rail potential, the no-load voltage of the rectifier unit, the rectifier starting voltage of the bidirectional current conversion device, and the voltage regulation range of the bidirectional current conversion device. If the maximum value of the rail potential is lower than the limit value, i.e., Urail < Urailmax; the rectifier starting voltage V3 of the bidirectional current conversion device is greater than the no-load voltage U0 of the rectifier unit, i.e., V3 > U0; the droop voltage regulation range of the bidirectional current conversion device does not exceed the maximum and minimum voltage limits, i.e., Umin < Ul < Umax; and the flag bit Flag = 1 and Logo = 1, it indicates that the power interaction between trains in the section has not been fully achieved, and the utilization rate of the regenerative braking energy on the DC side has not reached the maximum effect. In this case, increase the droop slope ri of the bidirectional current conversion device at the current moment by one step size k to obtain the droop slope ri+1 = ri + k for the next moment at this substation; at the same time, decrease the rectifier starting voltage V3i of the bidirectional current conversion device at the current moment by one step size h to obtain the rectifier starting voltage V3i+1 = V3i - h for the next moment at this substation, and increase the inverter starting voltage V6i of the bidirectional current conversion device at the current moment by one step size h to obtain the inverter starting voltage V6i+1 = V6i + h for the next moment at this substation.

[0107] Step Eleven: If the flag bit Flag = 0 and Logo = 0, it indicates that the power interaction between trains in the section has been fully achieved or there is no need for power interaction between trains in the section, and the utilization rate of the regenerative braking energy on the DC side has reached the maximum effect. At this time, continuously increasing the droop slope, decreasing the rectifier starting voltage, and increasing the inverter starting voltage will increase unnecessary line losses. Therefore, decrease the droop slope ri of the bidirectional current conversion device at the substation by one step size k, and at the same time, increase the rectifier starting voltage V3i of the bidirectional current conversion device at the current moment by one step size h, and decrease the inverter starting voltage V6i by one step size h.

[0108] Step Twelve: If the maximum value of the rail potential reaches the limit value, i.e., Urail ≥ Urailmax, it indicates that the external characteristic adjustment amount of the bidirectional current conversion device is too large. It is necessary to decrease the droop slope of the bidirectional current conversion device in the substation by one step size k, increase the rectifier starting voltage V3i of the bidirectional current conversion device at the current moment by one step size h, and decrease the inverter starting voltage V6i by one step size h to prevent the rail potential from exceeding the limit.

[0109] Step Thirteen: If the rectifier starting voltage V3 of the bidirectional current conversion device is less than the no-load voltage U0 of the rectifier unit, i.e., V3 < U0, it may cause the problem of countercurrent operation between the bidirectional current conversion device and the rectifier unit. Therefore, it is necessary to increase the rectifier starting voltage V3i of the bidirectional current conversion device at the current moment by one step size h, and decrease the inverter starting voltage V6i of the bidirectional current conversion device at the current moment by one step size h to avoid the occurrence of countercurrent problems.

[0110] Step Fourteen: If the voltage sag range of the bidirectional converter exceeds the maximum or minimum voltage limit, i.e., Ud < Umin or Ud > Umax, the excessive DC voltage may affect the full braking of the train, and the too low DC voltage may affect the normal operation of the bidirectional converter. Therefore, at this time, it is necessary to reduce the voltage sag slope of the bidirectional converter in the substation by one step k, increase the rectification starting voltage V3i of the bidirectional converter at the current moment by one step h, and reduce the inversion starting voltage V6i of the bidirectional converter at the current moment by one step h to avoid the DC voltage exceeding the range; after adjusting the voltage sag slope and starting voltage of the bidirectional converter in the regulating station within the partition at the current moment, generate the voltage sag slope reference instruction and starting voltage reference instruction of the bidirectional converter to control the DC voltage output of the bidirectional converter. Among them, the voltage sag slope adjustment step k and the starting voltage adjustment step h are selected according to the adjustment period. The shorter the adjustment period, the smaller the adjustment step, and the higher the sensitivity of the adaptive control. At the same time, it is necessary to ensure that the communication transmission rate of the entire energy management system meets the requirements.

[0111] Embodiment 2

[0112] The present invention also provides a bidirectional converter energy collaborative control system for implementing the bidirectional converter energy collaborative control method described above, which is applied to the bidirectional converter in the urban rail transit traction power supply system. Refer to Figure 7 As shown, the system includes:

[0113] The partition management module 100 is used to determine the partition of the regulating station according to the preset partition strategy, where the preset partition strategy is to use the selected regulating substation as the center and the two regulating substations before and after it as the collaborative control stations as a partition for partition management.

[0114] The area identification module 200 is used to determine all trains and all substations belonging to the partition based on the control range of the partition.

[0115] The power interaction analysis module 300 is used to obtain the interaction parameters of the power between trains according to the power parameters of the trains in the partition and the power parameters of the substations in the partition.

[0116] The voltage judgment module 400 is used to obtain multiple voltage judgment results based on multiple preset voltage judgment conditions, where the multiple voltage judgment conditions include judging whether the maximum value of the rail potential obtained is less than the limit value, whether the rectification starting voltage of the bidirectional converter is less than the no-load voltage of the rectifier unit, and whether the voltage regulation range of the bidirectional converter exceeds the defined range.

[0117] The dynamic adjustment module 500 is used to dynamically adjust the droop slope and starting voltage of the bidirectional converter device in combination with the multiple voltage judgment results and the interaction parameters of the power between trains, so as to realize the coordinated control of the bidirectional converter device.

[0118] The present application is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0119] Those skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage medium includes a read-only memory (ROM), a random access memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a one-time programmable read-only memory (OTPROM), an electronically erasable programmable read-only memory (EEPROM), a compact disc (CD-ROM) or other optical disc storage, magnetic disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0120] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

Claims

1. A method for energy cooperative control of a bidirectional converter, applied to a bidirectional converter in a traction power supply system of urban rail transit, characterized in that: The method comprises the following steps: Determine the partition of the control station according to a preset partition strategy, wherein the preset partition strategy is to manage the partition as a partition with the selected control substation as the center and the two control substations before and after it as the collaborative control station; Determine all trains and all substations belonging to the partition based on the control range of the partition; Acquiring an interaction parameter of power between trains according to power parameters of trains in the zone and power parameters of substations in the zone; Acquire multiple voltage judgment results based on multiple preset voltage judgment conditions, wherein the multiple voltage judgment conditions include judging whether the maximum value of the rail potential acquired is less than the limit value, whether the rectifier starting voltage of the bidirectional converter is less than the no-load voltage of the rectifier unit, and whether the voltage adjustment range of the bidirectional converter exceeds the limit range; The droop slope and starting voltage of the bidirectional converter are dynamically adjusted in combination with the multiple voltage judgment results and the interaction parameters of the power between trains to achieve coordinated control of the bidirectional converter.

2. The method for energy coordinated control of a bidirectional converter according to claim 1, characterized in that: The preset partitioning strategy also includes: For the two control substations at the front end of the line, the existing control substation in front and the two control substations behind are selected as the sub-area, and for the two control substations at the end of the line, the two control substations in front and the existing control substation behind are selected as the sub-area.

3. The method for energy coordinated control of a bidirectional converter device according to claim 2, characterized in that: Methods for determining trains within a zone include: Determine the distance between the first and last control substations in the zone and the departure station, collect the location information of each train, compare the train location information with the distance, and determine whether the train is in the zone.

4. The method for energy coordinated control of a bidirectional converter according to claim 3, characterized in that: Methods for obtaining the interaction parameters of power between trains include: Collect train power information within the zone to determine whether each train is in traction or braking state; For each train, if its power is greater than zero, it is determined that the train is in traction state, and the traction power of the train is recorded; if the power is less than zero, it is determined that the train is in braking state, and the braking power of the train is recorded; The traction power and braking power of all trains in the section are summed up respectively to obtain the total traction power and braking power in the section as the interaction parameters of the power between trains.

5. The method for energy coordinated control of a bidirectional converter device according to claim 4, characterized in that: Methods for obtaining power parameters of a substation include: Collect the voltage and current values ​​of the rectifier units of each traction substation in the zone and calculate the power of the rectifier units; Collect the voltage and current values ​​of the bidirectional converters of each traction substation in the zone and calculate the power of the bidirectional converters; The rectifier power and inverter power of each substation in the zone are summed up respectively to obtain the total rectifier power and inverter power in the zone.

6. A method for energy coordinated control of a bidirectional converter device according to claim 5, characterized in that: The method for obtaining multiple voltage judgment results based on the multiple voltage judgment conditions includes: Real-time monitoring and acquisition of the maximum value of rail potential; Check whether the rectifier starting voltage of the bidirectional converter is always higher than the no-load voltage of the rectifier unit; Confirm whether the voltage regulation range of the bidirectional converter device remains between the preset maximum and minimum voltage limits; When any voltage judgment condition is not met, the corresponding adjustment mechanism is triggered.

7. The method for energy coordinated control of a bidirectional converter device according to claim 6, characterized in that: The method also includes the steps of setting the initial droop slope and the starting voltage of the bidirectional converter, specifically including: The rectifier starting voltage V3 of the bidirectional converter is set based on the rated no-load voltage of the rectifier unit to ensure that V3 is greater than the no-load voltage of the rectifier unit; The inverter starting voltage V6 is set based on the rectifier starting voltage V3 of the bidirectional converter to ensure that V6 is greater than V3, so as to prevent the circulation operation problem of the bidirectional converters between different stations; After the initial setup is completed, the 35kV dynamic grid voltage on the AC side of the rectifier units at all stations along the entire line is monitored in real time, and the dynamic no-load voltage of the rectifier units is calculated to adapt to grid fluctuations and ensure stable system operation.

8. The method for energy coordinated control of a bidirectional converter device according to claim 7, characterized in that: The method for dynamically adjusting the droop slope and the starting voltage of the bidirectional converter device in combination with the multiple voltage judgment results and the train-to-train power interaction parameters includes: Set the droop slope adjustment flag Flag and the starting voltage adjustment flag Logo of the bidirectional converter device; Update the status of the flag bit according to the train power interaction situation and substation power situation in the section; According to the state of the flag bit and the voltage judgment result, it is determined whether the droop slope and the starting voltage of the bidirectional converter need to be adjusted; If adjustment is required, the droop slope, rectifier start voltage and inverter start voltage are adjusted incrementally or decrementally according to the preset step sizes k and h respectively; When the train in the section is in both traction and braking state and full power interaction is not achieved, the droop slope of the bidirectional converter is increased, while the rectifier starting voltage is reduced and the inverter starting voltage is increased; When the trains in the section fully realize power interaction or there is no need for power interaction between trains, the droop slope of the bidirectional converter is reduced, while the rectifier starting voltage is increased and the inverter starting voltage is reduced; When the rail potential reaches or exceeds the limit value, the droop slope of the bidirectional converter is reduced, while the rectifier starting voltage is increased and the inverter starting voltage is reduced; When the rectifier starting voltage of the bidirectional converter is lower than the no-load voltage of the rectifier unit, the rectifier starting voltage of the bidirectional converter is increased and the inverter starting voltage is reduced; When the voltage droop range of the bidirectional converter exceeds the maximum or minimum voltage limit, the droop slope of the bidirectional converter is reduced, and the rectifier starting voltage is increased and the inverter starting voltage is reduced.

9. The method for energy coordinated control of a bidirectional converter device according to claim 8, characterized in that: The adjustment mechanism includes: Rail potential over-limit adjustment mechanism: When the maximum rail potential reaches or exceeds the limit value, the droop slope of the bidirectional converter is automatically reduced, and the rectifier starting voltage and inverter starting voltage are adjusted accordingly; Rectification start voltage is lower than no-load voltage adjustment mechanism: when the rectification start voltage of the bidirectional converter is lower than the no-load voltage of the rectifier unit, the rectification start voltage is automatically increased and the inverter start voltage is reduced; Voltage droop range over-limit adjustment mechanism: When the voltage droop range of the bidirectional converter exceeds the maximum or minimum voltage limit, the droop slope is automatically reduced, and the rectifier starting voltage and inverter starting voltage are adjusted; Dynamic response adjustment mechanism: Dynamically adjust the droop slope and starting voltage of the bidirectional converter according to the train power interaction within the section and the substation power situation.

10. A bidirectional converter energy cooperative control system, used to execute a bidirectional converter energy cooperative control method according to any one of claims 1 to 9, applied to a bidirectional converter in an urban rail transit traction power supply system, characterized in that: The system comprises: A partition management module, used to determine the partitions of the control station according to a preset partition strategy, wherein the preset partition strategy is to perform partition management with the selected control substation as the center and the two control substations before and after it as collaborative control stations as one partition; An area identification module, used for determining all trains and all substations belonging to the zone based on the control range of the zone; A power interaction analysis module, used for obtaining the interaction parameters of power between trains according to the power parameters of the trains in the zone and the power parameters of the substations in the zone; A voltage judgment module is used to obtain multiple voltage judgment results based on multiple preset voltage judgment conditions, wherein the multiple voltage judgment conditions include judging whether the maximum value of the rail potential obtained is less than the limit value, whether the rectifier starting voltage of the bidirectional converter is less than the no-load voltage of the rectifier unit, and whether the voltage adjustment range of the bidirectional converter exceeds the limit range; A dynamic adjustment module is used to dynamically adjust the droop slope and starting voltage of the bidirectional converter device in combination with the multiple voltage judgment results and the interaction parameters of the power between trains, so as to realize the coordinated control of the bidirectional converter device.

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