An electromagnetically compensated in-phase power supply system and its control method

Abstract

This invention discloses an electromagnetically compensated in-phase power supply system and control method, relating to the field of electrified railway traction power supply technology. It includes a traction transformer, an electromagnetic compensation device, and a main controller. The traction transformer is a single-phase structure, while the electromagnetic compensation device is a three-phase structure. During operation, the traction transformer undertakes the traction power supply task, while the electromagnetic compensation device undertakes the tasks of negative sequence management and power factor compensation on the grid side. Each unit performs energy management and coordinated control through the system's main controller. This invention utilizes a single-phase traction transformer to provide in-phase power to the traction network, eliminating phase separation and train power outage zones. It employs pure electromagnetic compensation to achieve both distributed and centralized negative sequence management, and is compatible with new energy access on the traction side. Compared to traditional power electronic in-phase power supply schemes, this invention features a simpler system structure, higher capacity utilization, lower cost, higher operational reliability, and stronger engineering applicability, making it more conducive to safe, efficient, stable, and low-carbon train operation.

Description

Technical Field

[0001] This invention belongs to the field of electrified railway traction power supply technology, and in particular relates to an electromagnetic compensation type in-phase power supply system and control method. Background Technology

[0002] Electrified railways are the backbone of my country's comprehensive transportation system. They generally employ single-phase AC power supply. To balance the load of the three-phase power grid, traction substations typically use a phase-switching power supply method, requiring numerous phase-switching devices on the traction network. When trains pass through areas without power, problems such as power outages, speed drops, and pantograph-catenary arcing occur, restricting train throughput. Furthermore, single-phase traction loads have inherent characteristics such as impulsiveness and strong fluctuations, injecting a large amount of negative-sequence current into the power grid and deteriorating power quality. Therefore, to balance the negative-sequence current in the power grid, eliminate the drawbacks of phase-switching, and optimize power quality, in-phase power supply technology has become one of the research hotspots in the field of traction power supply in recent years.

[0003] Currently, the mainstream in-phase power supply schemes in China can be divided into active in-phase compensation schemes and reactive in-phase compensation schemes, depending on the form of compensation power used by the compensation device. The former is represented by combined in-phase power supply schemes based on static var generators and combined in-phase power supply schemes using standard connection groups, while the latter is represented by single-phase three-phase combined in-phase power supply schemes and single-phase combined in-phase power supply schemes. For example, the invention patent "In-phase power supply comprehensive compensation device and method based on traction-compensation transformer" (application number: 201811381657.1) uses four sets of static var generators and a specially connected traction transformer to achieve in-phase power supply and power quality compensation; the invention patent "An electrified railway in-phase traction power supply system" (application number: 201010123860.6) uses a three-phase to two-phase transformer, a step-down transformer and a single-phase AC-DC-AC converter to achieve in-phase power supply for both arms of the railway traction substation without phase separation; the invention patent "A single-phase and three-phase combined in-phase power supply and transformation device" (application number: 201210583674.X) is composed of a single-phase traction transformer, a three-phase YNd11 connected compensation transformer and its in-phase compensation device. The in-phase compensation device includes a single-phase AC-DC-AC converter and a single-phase transformer. This device can eliminate electrical phase separation and meet the requirements of three-phase voltage imbalance.

[0004] In summary, the normal operation of existing in-phase power supply schemes of various forms relies on large-capacity power electronic converters to simultaneously achieve in-phase regulation of traction side voltage and dynamic compensation of negative sequence power. However, these power electronic in-phase power supply schemes still face many technical challenges in engineering applications. On the one hand, traction loads themselves experience frequent forward and reverse random impact conditions, and existing in-phase power supply devices require a large number of high-power switching devices to operate at high frequencies, which leads to reduced equipment reliability and difficulties in engineering maintenance. On the other hand, existing power electronic in-phase power supply devices have relatively complex structures, high costs, and require complex control algorithms, which limits their engineering application. Therefore, it is urgent to study an electrified railway in-phase power supply system scheme that combines simple topology, high operational reliability, low cost, and is more conducive to engineering application. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes an electromagnetic compensation-type in-phase power supply system and control method. This system utilizes a simple single-phase traction transformer to provide in-phase power to the traction network, eliminating phase-splitting links and power outage zones for trains. A pure electromagnetic compensation structure is employed to achieve both negative sequence dispersion and centralized management, ensuring compliance with grid-connected power quality requirements and adaptability to new energy access on the traction side. Compared to traditional power electronic in-phase power supply schemes, this system features a simpler structure, higher capacity utilization, lower investment and maintenance costs, higher operational reliability, and stronger engineering applicability, thus promoting safer, more efficient, stable, and low-carbon train operation.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: an electromagnetic compensation type in-phase power supply system, comprising a traction transformer TT, an electromagnetic compensation device ECD, and a system main controller SMC; The traction transformer TT is a single-phase structure. The two ports of the primary winding are connected to the two-phase high-voltage input lines of the three-phase power grid. The port a0 of the secondary winding is connected to the traction bus TB circuit, and the port b0 is connected to the rail. The electromagnetic compensation device ECD has six terminals leading out to the outside. The rotor winding side input ports (A), (B) and (C) are connected to the three-phase high voltage input lines A, B and C of the three-phase power grid in sequence. The stator winding side output ports (a), (b) and (c) are connected to the three-phase high voltage input lines A, C and B of the three-phase power grid in sequence. The stator winding side output ports form a negative sequence connection. The system's main controller (SMC) monitors the electrical quantities and operating status of the traction transformer TT, the electromagnetic compensation device (ECD), and the traction bus TB in real time. It also performs energy management and coordinated control among the various units of the system to ensure that the traction transformer TT provides in-phase power to the traction network and undertakes the traction power supply task during normal operation. At the same time, the electromagnetic compensation device (ECD) undertakes the tasks of negative sequence management and power factor compensation, ensuring the safe, efficient, and stable operation of the train.

[0007] Furthermore, the electromagnetic compensation device ECD includes a first phase-shifting transformer RPST1, a second phase-shifting transformer RPST2, and a compensation capacitor CC. The starting ends of the three-phase rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in parallel with corresponding phases, and external ports (A), (B), and (C) are led out at each parallel connection point. The ends of the three-phase rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected to neutral points O1 and O2, respectively. The starting ends of the three-phase stator windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in series with corresponding phase windings. The stator winding ports a1, b1, and c1 of the first phase-shifting transformer lead out to external ports (a), (b), and (c), respectively. Ports x1, y1, and z1 are connected to the stator winding ports a2, b2, and c2 of the second phase-shifting transformer, respectively. Ports x2, y2, and z2 are connected to the three-phase compensation capacitor CC, respectively. a CC b CC c Series connection on one side, three-phase compensation capacitor CC a CC b CC c The other side is connected in a three-phase star configuration.

[0008] Furthermore, the electromagnetic compensation device ECD adopts an off-axis drive structure. According to the control signal, the rotor phase shift angle of each phase-shifting transformer can be independently controlled by the rotor shaft, rotor drive device and servo motor to realize continuous adjustment of the voltage amplitude and phase at the output port, thereby achieving the purpose of negative sequence and reactive power compensation.

[0009] Furthermore, the electromagnetic compensation type in-phase power supply system EC-CPS adopts a decentralized compensation scheme; under the decentralized compensation scheme, each traction substation is independently equipped with a traction transformer TT, an electromagnetic compensation device ECD, and a system main controller SMC. Each traction substation is autonomous and independently performs in-phase power supply and negative sequence management.

[0010] Furthermore, the electromagnetic compensation type in-phase power supply system EC-CPS adopts a centralized compensation scheme. Under the centralized compensation scheme, the electromagnetic compensation type in-phase power supply system EC-CPS provides in-phase power to the traction substation group and performs centralized management of negative sequence. Multiple traction transformers TT adopt a phase-switching connection method. By switching the phase connection, the negative sequence compensation demand on the grid side is reduced, thereby reducing the required capacity of the electromagnetic compensation device ECD.

[0011] Furthermore, the centralized compensation scheme uses three traction substations as grouped cyclic units, thus the electromagnetic compensation type in-phase power supply system EC-CPS includes a first traction transformer TT1, a second traction transformer TT2, a third traction transformer TT3, an electromagnetic compensation device ECD, and a system main controller SMC; the primary sides of the first traction transformer TT1, the second traction transformer TT2, and the third traction transformer TT3 are connected to the three-phase power grid high-voltage incoming lines AC, AB, and BC respectively in a phase sequence alternation manner, and one port of each secondary side is connected to the traction bus TB1, TB2, and TB3 circuits respectively, and the other port is connected to the rail; the system main controller SMC regulates the electromagnetic compensation device to centrally manage the negative sequence in the three traction substations.

[0012] Furthermore, the electromagnetic compensation type in-phase power supply system EC-CPS is also connected to a single-phase new energy power supply unit NEPU. The AC output port d of the single-phase new energy power supply unit NEPU is connected to the traction bus TB circuit, and the port e is connected to the rail. The single-phase new energy power supply unit (NEPU) includes a DC power supply DS, a single-phase DC / AC converter SDA, and a single-phase transformer ST. The DC power supply DS is connected to the DC side circuit of the single-phase DC / AC converter SDA, the AC side of the single-phase DC / AC converter SDA is connected to the primary winding of the single-phase transformer ST, and the secondary winding of the single-phase transformer ST has AC output ports d and e. The system's main controller SMC also monitors the electrical quantities and operating status of the single-phase new energy power supply unit (NEPU) in real time and performs energy management and coordinated control.

[0013] On the other hand, based on the electromagnetically compensated in-phase power supply system, the present invention also provides a control method for the electromagnetically compensated in-phase power supply system, comprising the following steps: S1, Data Acquisition and Analysis; Acquires real-time operating data from the traction busbar TB side, electromagnetic compensation device ECD side, traction transformer TT side, and power grid side, and performs data analysis and processing; Let be the load equivalent current of the primary side of the traction transformer TT. Then, the three-phase currents at the point of common coupling on the grid side satisfy... , , The negative sequence current component generated by the traction load at the point of common coupling on the grid side is obtained by decomposition methods such as the symmetrical component method. ;set up This refers to the compensation current output by the electromagnetic compensation device ECD. Since the output port of the ECD stator winding is reverse-connected, then... and The opposite phases cancel each other out. S2, Calculation of demand compensation current; At the point of common coupling on the grid side, the negative sequence current balance relationship is satisfied, and the remaining negative sequence current on the grid side after compensation is... Combined with the power grid short-circuit capacity S d Three-phase power grid rated voltage U N And the allowable value ε for negative sequence voltage imbalance. U The permissible negative sequence current limit was calculated. I lim- To meet the assessment requirements for negative-order indicators, the control objective should preferably satisfy... The required electromagnetic compensation current command for the ECD (Electromagnetic Compensation Device) is obtained by solving the problem. ; S3, Calculation of required compensation voltage; assuming the structural parameters of the first and second phase-shifting transformers in the electromagnetic compensation device ECD are the same, then the total compensation voltage output from the stator circuit of the electromagnetic compensation device ECD will satisfy... ,in k The turns ratio constant of a single phase-shifting transformer. α 1 and α 2 represents the rotor phase shift angle of the first and second phase-shifting transformers, respectively. The positive-sequence phase voltage of the power grid; based on the ECD compensation current command of the magnetic compensation device obtained from S2. Then, the required compensation voltage for the electromagnetic compensation device ECD can be obtained by solving the problem in the stator circuit. ,in The total equivalent impedance on the stator side of the electromagnetic compensation device ECD; the average angle of the electromagnetic compensation device is introduced. , half angle difference Substituting into the voltage relationship and simplifying, we get ,thereby The amplitude is determined by the half-angle difference. d Control, phase is determined by average angle c control; S4, calculate the rotor phase shift angle; solve for the direct relationship between the compensation voltage and the rotor angle, derived from S3. When the demand compensation is greater d The smaller the value, the smaller the demand compensation amount. d The larger; and at the same time, it is derived that To ensure that the phase of the compensation current is always opposite to the negative sequence current of the load, so as to achieve precise cancellation; to obtain the rotor phase shift angle command values ​​α1 and α2 required by the first and second phase shift transformers in the electromagnetic compensation device ECD; S5, driven independently by a servo motor, enables dual rotors to complete the target phase shift angle deflection and outputs the required compensation current. The system synchronously completes the negative sequence compensation task, realizes in-phase traction power supply, and ensures that the negative sequence voltage imbalance meets the power quality requirements. The electromagnetic compensation device ECU bottom layer coordinates and controls the state of the servo motor by setting up a compensation current control link, a phase shift angle set value calculation link, a phase shift angle coordinated speed control link, and a flexible loop control link, thereby ensuring the coordinated operation of the first phase shift transformer and the second phase shift transformer.

[0014] Furthermore, when a single-phase new energy power supply unit (NEPU) is also connected to the electromagnetic compensation type in-phase power supply system EC-CPS, in the system control flow S1-S5, when calculating the compensation current required by the electromagnetic compensation device ECD, the compensation current provided by the new energy power supply unit (NEPU) should be subtracted, and then the corresponding rotor phase shift angle should be solved according to the compensation command and coordinated control should be performed.

[0015] Furthermore, when the electromagnetic compensation type in-phase power supply system EC-CPS adopts a centralized compensation scheme, in the system control flow S1-S5, when calculating the required compensation current of the electromagnetic compensation device ECD, the negative sequence current part generated by the traction load at the grid-side common connection point should first be adjusted to the negative sequence current component of the total equivalent load generated by the traction substation group, and then the corresponding rotor phase shift angle should be solved according to the compensation command and coordinated control should be performed.

[0016] The beneficial effects of adopting this technical solution are: This invention provides an electromagnetic compensation-type in-phase power supply system that uses the simplest single-phase traction transformer to provide in-phase power to the traction network. It can eliminate the phase-splitting link and eliminate the train power outage zone. It does not rely on high-power power electronic devices during operation. It adopts a pure electromagnetic compensation structure to achieve negative sequence dispersion and centralized management, so as to meet the grid-connected power quality requirements. Compared with the traditional power electronic in-phase power supply scheme, the system has a simple structure, high capacity utilization, low investment and operation and maintenance costs, high operational reliability, and strong engineering applicability, which is more conducive to the safe, efficient and stable operation of trains.

[0017] The electromagnetic compensation type in-phase power supply system control method provided by this invention can perform energy management and coordinated control among various units of the system, adapt to different operating schemes of distributed compensation and centralized compensation, ensure that the traction transformer provides in-phase power to the traction network and undertakes the traction power supply task during normal operation, and the electromagnetic compensation device undertakes the tasks of negative sequence management and power factor compensation. When new energy is connected on the traction side, it can perform in-phase traction power supply, new energy consumption and power quality management tasks, which is conducive to the green, low-carbon, efficient and sustainable development of the railway system.

[0018] The electromagnetic compensation device provided by this invention is a novel negative sequence compensation device for railway in-phase power supply. It does not require any power electronic converter devices. Through stator and rotor coordinated regulation, it can achieve dynamic compensation of power quality at the common connection point on the grid side. At the same time, the electromagnetic compensation device has simple control logic, does not require complex power calculation and DC voltage regulation links, has high system stability, strong anti-interference ability, and is easy to apply in engineering. Attached Figure Description

[0019] Figure 1 This is a structural diagram of an electromagnetically compensated in-phase power supply system according to the present invention; Figure 2 This is a topological diagram of the electromagnetic compensation device in an embodiment of the present invention; Figure 3 This is a structural diagram of an electromagnetically compensated in-phase power supply system under a centralized compensation scheme in an embodiment of the present invention; Figure 4 This is a structural diagram of an electromagnetically compensated in-phase power supply system with a new energy power supply unit, as described in an embodiment of the present invention. Figure 5 This is a flowchart of a control method for an electromagnetically compensated in-phase power supply system according to the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to the accompanying drawings.

[0021] In this embodiment, see Figure 1 As shown, this invention proposes an electromagnetically compensated in-phase power supply system, comprising: a traction transformer TT, an electromagnetic compensation device ECD, and a system main controller SMC; the traction transformer TT is a single-phase structure, with two ports of the primary winding connected to two high-voltage input lines of a three-phase power grid, and port a0 of the secondary winding connected to the traction bus TB circuit, and port b0 connected to the rail; the electromagnetic compensation device ECD has six terminals leading out, with the rotor winding side input ports (A), (B), and (C) sequentially connected to the three-phase high-voltage input lines A, B, and C of the three-phase power grid, and the stator winding side output terminal... Ports (a), (b), and (c) are respectively connected to the three-phase high-voltage incoming lines A, C, and B of the three-phase power grid, and the output ports on the stator winding side form a negative sequence connection. The system's main controller (SMC) monitors the electrical quantities and operating status of the traction transformer TT, the electromagnetic compensation device (ECD), and the traction bus TB in real time, and performs energy management and coordinated control between the various units of the system. This ensures that during normal operation, the traction transformer TT provides in-phase electrical energy to the traction network and undertakes the traction power supply task. At the same time, the electromagnetic compensation device (ECD) undertakes the tasks of negative sequence management and power factor compensation, ensuring the safe, efficient, and stable operation of the train.

[0022] As an optimization of the above embodiments, such as Figure 2 As shown, the electromagnetic compensation device ECD includes a first phase-shifting transformer RPST1, a second phase-shifting transformer RPST2, and a compensation capacitor CC. The starting ends of the three-phase rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in parallel with corresponding phases. External ports (A), (B), and (C) are led out at each parallel connection point. The ends of the three-phase rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected to neutral points O1 and O2, respectively. The three-phase stator windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in series with corresponding phase windings. Ports a1, b1, and c1 of the first phase-shifting transformer stator winding lead out to external ports (a), (b), and (c), respectively. Ports x1, y1, and z1 are connected to ports a2, b2, and c2 of the second phase-shifting transformer stator winding, respectively. Ports x2, y2, and z2 are connected to the three-phase compensation capacitor CC, respectively. a CC b CC c Series connection on one side, three-phase compensation capacitor CC a CC b CC c The other side is connected in a three-phase star configuration.

[0023] Preferably, the electromagnetic compensation device (ECD) adopts an off-axis drive structure. According to the control signal, the rotor phase shift angle of each phase-shifting transformer can be independently controlled by the rotor shaft, rotor drive device and servo motor to realize continuous adjustment of the voltage amplitude and phase at the output port, thereby achieving the purpose of negative sequence and reactive power compensation.

[0024] As an optimization of the above embodiments, the electromagnetic compensation type in-phase power supply system EC-CPS can adopt a decentralized compensation scheme. Under the decentralized compensation scheme, each traction substation is independently equipped with a traction transformer TT, an electromagnetic compensation device ECD, and a system main controller SMC. Each traction substation is autonomous and independently performs in-phase power supply and negative sequence management.

[0025] As an optimization of the above embodiments, the electromagnetic compensation type in-phase power supply system EC-CPS can also adopt a centralized compensation scheme. Under the centralized compensation scheme, the electromagnetic compensation type in-phase power supply system EC-CPS provides in-phase power to the traction substation group and performs centralized management of negative sequence. Multiple traction transformers TT adopt a phase-switching connection method. By switching the phase connection, the negative sequence compensation demand on the grid side is reduced, thereby reducing the required capacity of the electromagnetic compensation device ECD.

[0026] As an optimization of the above embodiments, such as Figure 3As shown, this is an electromagnetic compensation type in-phase power supply system under a centralized compensation scheme of the present invention. The centralized compensation scheme preferably uses three traction substations as grouped cyclic units, thus the electromagnetic compensation type in-phase power supply system EC-CPS includes a first traction transformer TT1, a second traction transformer TT2, a third traction transformer TT3, an electromagnetic compensation device ECD, and a system main controller SMC. The primary sides of the first traction transformer TT1, the second traction transformer TT2, and the third traction transformer TT3 are respectively connected to the three-phase power grid high-voltage incoming lines AC, AB, and BC using a phase-sequence alternation method. One port of each secondary side is connected to the traction bus TB1, TB2, and TB3 circuits respectively, and the other port is connected to... The electromagnetic compensation device (ECD) has its rotor winding side input ports (A), (B), and (C) connected sequentially to the three-phase high-voltage incoming lines A, B, and C of the three-phase power grid. Its stator winding side output ports (a), (b), and (c) are connected to the three-phase high-voltage incoming lines A, C, and B of the three-phase power grid, respectively, forming a negative sequence connection. The system's main controller (SMC) monitors the electrical quantities and operating status of the traction transformer, the electromagnetic compensation device, and the traction bus in real time, and performs energy management and coordinated control between system units. This ensures that during normal operation, the traction transformers in each substation provide in-phase power to the power supply section, while the electromagnetic compensation device centrally manages the negative sequence within the three traction substations.

[0027] As an optimization of the above embodiments, such as Figure 4 As shown, this invention provides an electromagnetically compensated in-phase power supply system with a new energy power supply unit (EC-CPS). The EC-CPS also includes a single-phase new energy power supply unit (NEPU). The NEPU's AC output port d is connected to the traction bus TB circuit, and port e is connected to the rail. The NEPU includes a DC power supply DS, a single-phase DC / AC converter SDA, and a single-phase transformer ST. The DC power supply DS is connected to the DC side circuit of the single-phase DC / AC converter SDA, and the AC side of the single-phase DC / AC converter SDA is connected to the primary winding of the single-phase transformer ST. The secondary winding of the single-phase transformer ST leads out AC output ports d and e. The system's main controller SMC monitors the electrical quantities and operating status of the traction transformer TT, the electromagnetically compensated device ECD, the single-phase new energy power supply unit NEPU, and the traction bus TB in real time, and performs energy management and coordinated control between the system's units to achieve in-phase traction power supply, efficient consumption of new energy, and power quality management.

[0028] To facilitate the implementation of the system of this invention, based on the same inventive concept, such as Figure 5 As shown, the present invention also provides a control method for an electromagnetically compensated in-phase power supply system, comprising the following steps: S1, Data Acquisition and Analysis; Acquires real-time operating data from the traction busbar TB side, electromagnetic compensation device ECD side, traction transformer TT side, and power grid side, and performs data analysis and processing; Let be the load equivalent current of the primary side of the traction transformer TT. Then, the three-phase currents at the point of common coupling on the grid side satisfy... The negative sequence current component generated by the traction load at the point of common coupling on the grid side can be obtained by decomposition methods such as the symmetrical component method. ;set up This refers to the compensation current output by the electromagnetic compensation device ECD. Since the output port of the ECD stator winding is reverse-connected, then... and The opposite phases cancel each other out. S2, Calculation of demand compensation current; At the point of common coupling on the grid side, the negative sequence current balance relationship is satisfied, and the remaining negative sequence current on the grid side after compensation is... Combined with the power grid short-circuit capacity S d Three-phase power grid rated voltage U N and the allowable value of negative sequence voltage imbalance. e U The permissible negative sequence current limit was calculated. I lim- Preferred To meet the assessment requirements for negative-order indicators, the control objective should preferably satisfy... The required electromagnetic compensation current command for the ECD (Electromagnetic Compensation Device) is obtained by solving the problem. ; S3, Calculation of required compensation voltage; preferably, the first and second phase-shifting transformers in the electromagnetic compensation device ECD have the same structural parameters, then the total compensation voltage output of the stator circuit of the electromagnetic compensation device ECD satisfies... ,in k The turns ratio constant of a single phase-shifting transformer. α 1 and α 2 represents the rotor phase shift angle of the first and second phase-shifting transformers, respectively. The positive-sequence phase voltage of the power grid; based on the ECD compensation current command of the magnetic compensation device obtained from S2. Then, the required compensation voltage for the electromagnetic compensation device ECD can be solved in the stator circuit. ,in The total equivalent impedance on the stator side of the electromagnetic compensation device ECD; preferably, the average angle of the electromagnetic compensation device is introduced. , half angle difference Substituting into the voltage relationship and simplifying, we get It is easy to know The amplitude is determined by the half-angle difference. d Control, phase is determined by average angle c control; S4, calculate the rotor phase shift angle; solve for the direct relationship between the compensation voltage and the rotor angle, which can be derived from S3. It is easy to see that the larger the demand compensation amount, the more... d The smaller the value, the smaller the demand compensation amount. d The larger it is; at the same time, it can be deduced that This ensures that the phase of the compensation current is always opposite to the negative sequence current of the load, achieving precise cancellation; furthermore, the required rotor phase shift angle command values ​​of the first and second phase shift transformers in the electromagnetic compensation device ECD can be obtained. α 1 and α 2. Preferred α 1 =c+d , α 2= c-d ; S5, driven independently by a servo motor, enables dual rotors to complete the target phase shift angle deflection and outputs the required compensation current. The system synchronously completes the negative sequence compensation task, realizes in-phase traction power supply, and ensures that the negative sequence voltage imbalance meets the power quality requirements. The electromagnetic compensation device ECU bottom layer coordinates and controls the state of the servo motor by setting up a compensation current control link, a phase shift angle set value calculation link, a phase shift angle coordinated speed control link, and a flexible loop control link, thereby ensuring the coordinated operation of the first and second phase shift transformers.

[0029] As an optimization of the above embodiment, when a single-phase new energy power supply unit (NEPU) is also connected to the electromagnetic compensation type in-phase power supply system EC-CPS, in the system control flow S1-S5, when calculating the compensation current required by the electromagnetic compensation device ECD, the compensation current provided by the new energy power supply unit (NEPU) should be subtracted, and then the corresponding rotor phase shift angle should be solved according to the compensation command and coordinated control should be performed.

[0030] As an optimization of the above embodiments, when the electromagnetic compensation type in-phase power supply system EC-CPS adopts a centralized compensation scheme, in the system control flow S1-S5, when calculating the required compensation current of the electromagnetic compensation device ECD, the negative sequence current part generated by the traction load at the grid-side common connection point should first be adjusted to the negative sequence current component of the total equivalent load generated by the traction substation group, and then the corresponding rotor phase shift angle should be solved according to the compensation command and coordinated control should be performed.

[0031] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An electromagnetically compensated in-phase power supply system, characterized in that, include: Traction transformer TT, electromagnetic compensation device ECD, and system main controller SMC; The traction transformer TT is a single-phase structure. The two ports of the primary winding are connected to the two-phase high-voltage input lines of the three-phase power grid. The port a0 of the secondary winding is connected to the traction bus TB circuit, and the port b0 is connected to the rail. The electromagnetic compensation device ECD has six terminals leading out to the outside. The rotor winding side input ports A, B and C are connected to the three-phase high voltage input lines A, B and C of the three-phase power grid in sequence. The stator winding side output ports a, b and c are connected to the three-phase high voltage input lines A, C and B of the three-phase power grid in sequence. The stator winding side output ports form a negative sequence connection. The system's main controller (SMC) monitors the electrical quantities and operating status of the traction transformer TT, the electromagnetic compensation device (ECD), and the traction bus TB in real time. It also performs energy management and coordinated control among the various units of the system to ensure that the traction transformer TT provides in-phase power to the traction network and undertakes the traction power supply task during normal operation. At the same time, the electromagnetic compensation device (ECD) undertakes the tasks of negative sequence management and power factor compensation, ensuring the safe, efficient, and stable operation of the train.

2. The electromagnetic compensation type in-phase power supply system according to claim 1, characterized in that, The electromagnetic compensation device ECD includes a first phase-shifting transformer RPST1, a second phase-shifting transformer RPST2, and a compensation capacitor CC. The starting ends of the three-phase rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in parallel with corresponding phases. External ports A, B, and C are led out at each parallel connection point. The ends of the three-phase rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected to neutral points O1 and O2, respectively. The three-phase stator windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in series with corresponding phase windings. Ports a1, b1, and c1 of the stator winding of the first phase-shifting transformer lead out to external ports a, b, and c, respectively. Ports x1, y1, and z1 are connected to ports a2, b2, and c2 of the stator winding of the second phase-shifting transformer, respectively. Ports x2, y2, and z2 are connected to the three-phase compensation capacitor CC, respectively. a CC b CC c Series connection on one side, three-phase compensation capacitor CC a CC b CC c The other side is connected in a three-phase star configuration.

3. The electromagnetic compensation type in-phase power supply system according to claim 2, characterized in that, The electromagnetic compensation device (ECD) adopts an off-axis drive structure. Based on the control signal, the rotor phase shift angle of each phase-shifting transformer can be independently controlled by the rotor shaft, rotor drive device and servo motor to realize continuous adjustment of the output port voltage amplitude and phase, and achieve the purpose of negative sequence and reactive power compensation.

4. An electromagnetically compensated in-phase power supply system according to claim 2 or 3, characterized in that, The electromagnetic compensation type in-phase power supply system EC-CPS adopts a decentralized compensation scheme. Under the decentralized compensation scheme, each traction substation is independently equipped with a traction transformer TT, an electromagnetic compensation device ECD, and a system main controller SMC. Each traction substation is autonomous and independently performs in-phase power supply and negative sequence management.

5. An electromagnetically compensated in-phase power supply system according to claim 2 or 3, characterized in that, The electromagnetic compensation type in-phase power supply system EC-CPS adopts a centralized compensation scheme. Under the centralized compensation scheme, the electromagnetic compensation type in-phase power supply system EC-CPS provides in-phase power to the traction substation group and performs centralized management of negative sequence. Multiple traction transformers TT adopt a phase-switching connection method. By switching the phase connection, the negative sequence compensation demand on the grid side is reduced, thereby reducing the required capacity of the electromagnetic compensation device ECD.

6. The electromagnetic compensation type in-phase power supply system according to claim 5, characterized in that, The centralized compensation scheme uses three traction substations as grouped cyclic units. The electromagnetic compensation type in-phase power supply system (EC-CPS) includes a first traction transformer TT1, a second traction transformer TT2, a third traction transformer TT3, an electromagnetic compensation device (ECD), and a system main controller (SMC). The primary sides of the first traction transformer TT1, the second traction transformer TT2, and the third traction transformer TT3 are connected to the three-phase power grid high-voltage incoming lines AC, AB, and BC respectively using a phase sequence alternation method. One port of each secondary side is connected to the traction bus TB1, TB2, and TB3 circuits respectively, and the other port is connected to the rail. The system main controller (SMC) regulates the electromagnetic compensation device to centrally manage the negative sequence within the three traction substations.

7. The electromagnetic compensation type in-phase power supply system according to claim 1, characterized in that, The electromagnetic compensation type in-phase power supply system EC-CPS is also connected to a single-phase new energy power supply unit NEPU. The AC output port d of the single-phase new energy power supply unit NEPU is connected to the traction bus TB circuit, and the port e is connected to the rail. The single-phase new energy power supply unit (NEPU) includes a DC power supply DS, a single-phase DC / AC converter SDA, and a single-phase transformer ST. The DC power supply DS is connected to the DC side circuit of the single-phase DC / AC converter SDA, the AC side of the single-phase DC / AC converter SDA is connected to the primary winding of the single-phase transformer ST, and the secondary winding of the single-phase transformer ST has AC output ports d and e. The system's main controller SMC also monitors the electrical quantities and operating status of the single-phase new energy power supply unit (NEPU) in real time and performs energy management and coordinated control.

8. A control method for an electromagnetically compensated in-phase power supply system, characterized in that, The electromagnetic compensation type in-phase power supply system includes: a traction transformer TT, an electromagnetic compensation device ECD, and a system main controller SMC. The traction transformer TT is a single-phase structure. The two ports of the primary winding are connected to two high-voltage input lines of a three-phase power grid. The port a0 of the secondary winding is connected to the traction bus TB circuit, and the port b0 is connected to the rail. The electromagnetic compensation device ECD has six terminals leading out. The rotor winding side input ports A, B, and C are connected to the three-phase high-voltage input lines A, B, and C of the three-phase power grid in sequence. The stator winding side output ports a, b, and c are connected to the three-phase high-voltage input lines A, C, and B of the three-phase power grid in sequence. The stator winding side output ports form a negative sequence connection. The system control process includes the following steps: S1, Data Acquisition and Analysis; Acquires real-time operating data from the traction busbar TB side, electromagnetic compensation device ECD side, traction transformer TT side, and power grid side, and performs data analysis and processing; Let be the load equivalent current of the primary side of the traction transformer TT. Then, the three-phase currents at the point of common coupling on the grid side satisfy... The negative sequence current component generated by the traction load at the point of common coupling on the grid side is obtained by decomposition methods such as the symmetrical component method. ;set up This refers to the compensation current output by the electromagnetic compensation device ECD. Since the output port of the ECD stator winding is reverse-connected, then... and The opposite phases cancel each other out. S2, Calculation of demand compensation current; At the point of common coupling on the grid side, the negative sequence current balance relationship is satisfied, and the remaining negative sequence current on the grid side after compensation is... Combined with the power grid short-circuit capacity S d Three-phase power grid rated voltage U N And the allowable value ε for negative sequence voltage imbalance. U The permissible negative sequence current limit was calculated. I lim- To meet the assessment requirements for negative-order indicators, the control objective must satisfy... The required electromagnetic compensation current command for the ECD (Electromagnetic Compensation Device) is obtained by solving the problem. ; S3, Calculation of required compensation voltage; assuming the structural parameters of the first and second phase-shifting transformers in the electromagnetic compensation device ECD are the same, then the total compensation voltage output from the stator circuit of the electromagnetic compensation device ECD will satisfy... ,in k Let α1 and α2 be the rotor phase shift angles of the first and second phase shift transformers, respectively, and α1 be the turns ratio constant of a single phase-shifting transformer. The positive-sequence phase voltage of the power grid; the compensation current command of the electromagnetic compensation device ECD obtained from S2. Then, the required compensation voltage for the electromagnetic compensation device ECD can be obtained by solving the problem in the stator circuit. ,in The total equivalent impedance on the stator side of the electromagnetic compensation device ECD; the average angle of the electromagnetic compensation device is introduced. , half angle difference Substituting into the voltage relationship and simplifying, we get ,thereby The amplitude is determined by the half-angle difference. δ Control, phase is determined by average angle γ control; S4, calculate the rotor phase shift angle; solve for the direct relationship between the compensation voltage and the rotor angle, derived from S3. The larger the demand compensation amount, the smaller δ becomes; the smaller the demand compensation amount, the smaller δ becomes. δ The larger; and at the same time, it is derived that To ensure that the phase of the compensation current is always opposite to the negative sequence current of the load, achieving precise cancellation; to obtain the required rotor phase shift angle command values ​​of the first and second phase shift transformers in the electromagnetic compensation device ECD. α 1 and α 2; S5, driven independently by a servo motor, enables dual rotors to complete the target phase shift angle deflection and outputs the required compensation current. The system synchronously completes the negative sequence compensation task, realizes in-phase traction power supply, and ensures that the negative sequence voltage imbalance meets the power quality requirements. The electromagnetic compensation device ECU bottom layer coordinates and controls the state of the servo motor by setting up a compensation current control link, a phase shift angle set value calculation link, a phase shift angle coordinated speed control link, and a flexible loop control link, thereby ensuring the coordinated operation of the first phase shift transformer and the second phase shift transformer.

9. The control method for an electromagnetically compensated in-phase power supply system according to claim 8, characterized in that, When a single-phase new energy power supply unit (NEPU) is also connected to the electromagnetic compensation type in-phase power supply system (EC-CPS), in the system control flow S1-S5, when calculating the compensation current required by the electromagnetic compensation device (ECD), the compensation current provided by the new energy power supply unit (NEPU) should be subtracted, and then the corresponding rotor phase shift angle should be solved according to the compensation command and coordinated control should be performed.

10. The control method for an electromagnetically compensated in-phase power supply system according to claim 8, characterized in that, When the electromagnetic compensation type in-phase power supply system EC-CPS adopts a centralized compensation scheme, in the system control flow S1-S5, when calculating the required compensation current of the electromagnetic compensation device ECD, the negative sequence current part generated by the traction load at the grid-side common connection point should first be adjusted to the negative sequence current component of the total equivalent load generated by the traction substation group, and then the corresponding rotor phase shift angle should be solved according to the compensation command and coordinated control should be performed.

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