Single three-phase combined electromagnetic type in-phase power supply system and control method

Abstract

This invention discloses a single-phase and three-phase combined electromagnetic in-phase power supply system and control method, relating to the field of electrified railway traction power supply technology. It includes a single-phase traction transformer, a three-phase-to-two-phase traction transformer, an electromagnetic in-phase compensation device, and a system main controller. During operation, the single-phase traction transformer undertakes the main traction power supply task, while the three-phase-to-two-phase traction transformer and the electromagnetic in-phase compensation device undertake auxiliary traction power supply and negative sequence management tasks. Each unit performs energy management and coordinated control through the main controller. This invention can transform existing traction substations using conventional three-phase-to-two-phase transformers into in-phase traction power supply systems, eliminating phase separation at the traction substation outlet, enabling the traction substation to provide in-phase power to the traction network while meeting grid-connected power quality requirements. The electromagnetic structure boasts high operational reliability and strong engineering applicability, and can be adapted to the retrofitting of existing electrified railway in-phase power supply lines and the integration of new energy sources along the traction side.

Description

Technical Field

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

[0002] Currently, my country's electrified railways generally use two-phase, out-of-phase power supply. To mitigate the negative sequence imbalance caused by single-phase traction loads on the three-phase power grid, traction substations typically employ a phase sequence rotation and phase-zone power supply scheme, with electrical phase-separation insulation links installed between adjacent power supply arms. When a train passes through an electrical phase separation, it must perform a power-off, coasting, and re-energization operation, which not only causes interruption of train traction power, fluctuations in operating speed, and loss of travel time, but also easily triggers transient overvoltages, overcurrents, and pantograph-catenary arcing. To eliminate electrical phase separation, balance the negative sequence of the power grid, and optimize power supply quality, in-phase power supply technology has become one of the technical requirements for upgrading the traction power supply system of electrified railways.

[0003] At present, the mainstream in-phase power supply schemes in China must rely on large-capacity power electronic converters to achieve voltage in-phase regulation and power compensation. Typical topologies include different combinations of in-phase power supply schemes based on compensation links such as static var generators, unified power flow controllers, and single-phase AC-DC-AC converters. 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 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 transformer and its single-phase in-phase compensation device. The in-phase compensation device includes an AC-DC-AC converter and a single-matching transformer. This device can eliminate electrical phase separation and meet the power quality compensation requirements mainly based on three-phase voltage imbalance.

[0004] In summary, while existing power electronic single-phase and three-phase combined in-phase power supply schemes can serve as upgrade solutions for electrified railways, they still suffer from drawbacks in actual operation, including high equipment costs, stringent heat dissipation and voltage withstand requirements, weak overload and impact resistance, system reliability limited by power devices, and the introduction of additional harmonics. Furthermore, the compensation capacity of various fully controlled power electronic devices within the system must be fully configured for unbalanced overload conditions, resulting in generally low capacity utilization and limited economic efficiency in heavy-load and high-load sections. Therefore, large-scale application in electrified railways currently faces certain limitations. Based on this, to adapt to the in-phase upgrade structure of most existing traction substations using conventional three-phase to two-phase transformer connections, it is still necessary to explore in-phase power supply system schemes for electrified railways that feature simple topology, high operational reliability, low investment and maintenance costs, and are more conducive to engineering application. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a single-phase and three-phase combined electromagnetic in-phase power supply system and control method. Through a pure electromagnetic compensation structure, existing traction substations using conventional three-phase to two-phase transformer connections can be converted into in-phase traction power supply systems. This eliminates phase separation at the substation outlet and removes train power outage zones, enabling the traction substation to supply in-phase power to the traction network while mitigating negative sequence to meet grid-connected power quality requirements. Compared to traditional power electronic single-phase and three-phase in-phase power supply schemes, this system eliminates the need for large-capacity power electronic converters and traction matching transformers, offers high reliability of the electromagnetic structure, and has strong engineering applicability. It can be adapted to the retrofitting of existing electrified railway in-phase power supply lines and the integration of new energy sources along the traction side.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a single-phase and three-phase combined electromagnetic in-phase power supply system, comprising: a single-phase traction transformer STT, a three-phase-to-two-phase traction transformer 3 / 2TT, an electromagnetic in-phase compensation device ECPD, and a system main controller SMC; The high-voltage side winding of the single-phase traction transformer STT is connected to any two high-voltage input lines in the three-phase power grid, and the port b of the low-voltage side winding is connected to the traction bus TB circuit, and the port c is connected to the rail. The three-phase to two-phase traction transformer 3 / 2TT has its high-voltage side windings connected to the three-phase power grid high-voltage input lines at its three ports, and its low-voltage side windings connected to the input ports X and Y of the electromagnetic in-phase compensation device ECPD at its two ports. The output port x of the electromagnetic in-phase compensation device ECPD is connected to the traction bus TB circuit, and the port y is connected to the rail; the single-phase traction transformer STT port b and the electromagnetic in-phase compensation device ECPD port x generate single-phase AC voltages with the same phase and frequency, which together power the traction bus TB, and then power the traction load TL on the power supply arm through the traction bus TB. The system's main controller (SMC) monitors the electrical quantities and operating status of the single-phase traction transformer (STT), the three-phase-to-two-phase traction transformer (3 / 2TT), the electromagnetic in-phase compensation device (ECPD), 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 during normal operation, the single-phase traction transformer (STT), the three-phase-to-two-phase traction transformer (3 / 2TT), and the electromagnetic in-phase compensation device (ECPD) jointly supply power to the traction bus. The single-phase traction transformer (STT) undertakes the main traction power supply task, while the three-phase-to-two-phase traction transformer (3 / 2TT) and the electromagnetic in-phase compensation device (ECPD) undertake the auxiliary traction power supply task and the negative sequence management task.

[0007] Furthermore, the electromagnetic in-phase compensation device (ECPD) is a single-phase structure, employing either a non-isolated electromagnetic in-phase compensation device ECPD1 or an isolated electromagnetic in-phase compensation device ECPD2. These different topologies of the electromagnetic in-phase compensation devices (ECPD) can, based on control signals and through coordinated control of the rotor phase shift angle, independently and continuously adjust the voltage phase and amplitude between the two AC output ports. On one hand, they generate a voltage with the same frequency and phase as the low-voltage side of the single-phase traction transformer STT between port x and port y. On the other hand, they can control the magnitude and direction of the compensation power in real time, achieving precise compensation of the negative sequence on the grid side.

[0008] Furthermore, the non-isolated electromagnetic in-phase compensation device ECPD1 includes a first phase-shifting transformer RPST1, a second phase-shifting transformer RPST2, and a compensation capacitor CC; the rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in parallel, and the stator windings are connected in series; wherein, the starting ends of the stator winding and rotor winding in the first phase-shifting transformer RPST1, and the starting end of the rotor winding in the second phase-shifting transformer RPST2 are connected together at port X; the starting end of the stator winding in the second phase-shifting transformer RPST2 is connected in series with the ending end of the stator winding in the first phase-shifting transformer RPST1, the ending end of the stator winding in the second phase-shifting transformer RPST2 is connected in series with one side of the compensation capacitor CC, and the other side of the compensation capacitor CC is connected to the circuit at port x; the circuit between port Y and port y of the non-isolated electromagnetic in-phase compensation device ECPD1 is continuous.

[0009] Furthermore, the non-isolated electromagnetic in-phase compensation device ECPD1 adopts an off-axis drive structure, wherein the rotor shaft of the first phase-shifting transformer is connected to the first rotor drive device RDD1, and the rotor is driven by the first servo motor SM1 to rotate independently with a phase shift angle θ1 to achieve phase adjustment; the rotor shaft of the second phase-shifting transformer is connected to the second rotor drive device RDD2, and the rotor is driven by the second servo motor SM2 to rotate independently with a phase shift angle θ2 to achieve phase adjustment.

[0010] Furthermore, the isolated electromagnetic in-phase compensation device ECPD2 includes a first phase-shifting transformer RPST1, a second phase-shifting transformer RPST2, and a compensation capacitor CC; the rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in parallel, and the parallel connection point is connected to port X and port Y respectively; the first section of the stator winding of the first phase-shifting transformer RPST1 is connected to the circuit at port x, the stator windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in series from beginning to end, the end of the stator winding of the second phase-shifting transformer RPST2 is connected in series with one side of the compensation capacitor CC, and the other side of the compensation capacitor CC is connected to the circuit at port y.

[0011] Furthermore, the isolated electromagnetic in-phase compensation device ECPD2 adopts an off-axis drive structure, with the phase shift angles of the two rotors being adjusted independently. The rotor shaft of the first phase shift transformer is connected to the first rotor drive device RDD1, and the rotor is driven by the first servo motor SM1 to rotate independently at a phase shift angle θ1 to achieve phase adjustment. The rotor shaft of the second phase shift transformer is connected to the second rotor drive device RDD2, and the rotor is driven by the second servo motor SM2 to rotate independently at a phase shift angle θ2 to achieve phase adjustment.

[0012] Furthermore, the three-phase to two-phase traction transformer 3 / 2TT includes, but is not limited to, YNd11 connection traction transformer, YNvd connection traction transformer, V-type connection three-phase to two-phase traction transformer, impedance matching balance transformer, Scott connection two-phase to three-phase transformer, cross connection three-phase to two-phase transformer or VX connection three-phase to two-phase transformer.

[0013] Furthermore, a single-phase new energy power supply unit (NEPU) is also connected. The AC output port d of the NEPU 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, 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 leads out AC output ports d and e.

[0014] On the other hand, the present invention also provides a control method for a single-phase and three-phase combined electromagnetic in-phase power supply system. Based on a single-phase and three-phase combined electromagnetic in-phase power supply system, the system includes: a single-phase traction transformer STT, a three-phase-to-two-phase traction transformer 3 / 2TT, an electromagnetic in-phase compensation device ECPD, and a system main controller SMC. The high-voltage side winding of the single-phase traction transformer STT is connected to two high-voltage incoming lines in a three-phase power grid. Port b of the low-voltage side winding of the single-phase traction transformer STT is connected to the traction bus TB circuit, and port c is connected to the rail. The three ports of the high-voltage side winding of the three-phase-to-two-phase traction transformer 3 / 2TT are respectively connected to the high-voltage incoming lines of the three-phase power grid, and the two ends of the low-voltage side winding... The ports are respectively connected to the input ports X and Y of the electromagnetic in-phase compensation device ECPD; the output port x of the electromagnetic in-phase compensation device ECPD is connected to the traction bus TB circuit, and port y is connected to the rail; the single-phase traction transformer STT port b and the electromagnetic in-phase compensation device ECPD port x generate single-phase AC voltages with the same phase and frequency, which together power the traction bus TB, and then provide energy to the traction load TL on the power supply arm via the traction bus TB; the system main controller SMC is connected to the single-phase traction transformer STT, the three-phase-to-two-phase traction transformer 3 / 2TT, the electromagnetic in-phase compensation device ECPD, and the traction bus TB signal; The system control process includes the following steps: S1, Data Acquisition and Processing: Acquire real-time operating data from the STT side of the single-phase traction transformer, the 3 / 2TT side of the three-phase to two-phase traction transformer, the ECPD side of the electromagnetic in-phase compensation device, the TB side of the traction bus, and the power grid side, and perform data analysis and processing. Using the voltage between ports b and c of the single-phase traction transformer STT as the reference voltage The output voltage between the x and y ports of the electromagnetic in-phase compensation device (ECPD) under in-phase conditions. Output compensation current Assume the output power of the single-phase traction transformer STT is... Electromagnetic in-phase compensation device (ECPD) output power Total traction load power ; Demand compensation power calculation: Combining the grid short-circuit capacity and the allowable value of negative sequence voltage imbalance specified in national standards, the allowable value of negative sequence power is calculated. To meet the negative sequence requirements, based on the 3 / 2TT topology of the three-phase to two-phase traction transformer, the wiring configuration, the traction load power, and the output power of the single-phase traction transformer, the required compensation power of the electromagnetic in-phase compensation device (ECPD) is determined. This makes the apparent equivalent negative sequence power on the grid side after compensation... ;set up mThis is the negative sequence power weighting coefficient generated at the point of common coupling of the power grid for a single-phase traction port. n This is the negative sequence power weighting coefficient that cancels out the in-phase compensation port at the point of common coupling of the power grid. m and n The value is determined by the winding connection, voltage phase, and current symmetry transformation characteristics of single-phase and three-phase to two-phase traction transformers, and is subject to the negative sequence index assessment requirements. If the three-phase to two-phase traction transformer is analyzed using a YNd11 connected transformer, then the apparent compensation power required by the electromagnetic in-phase compensation device (ECPD) should meet the following requirements. ; S3, Calculation of required compensation voltage; given that the three-phase to two-phase traction transformer and the electromagnetic in-phase compensation device side, as well as the single-phase traction transformer side, can be equivalent to two in-phase parallel power supplies, the compensation current is obtained. Affected by voltage difference, ,in The equivalent resistance of the power supply circuit. For the equivalent reactance of the power supply circuit, Including the equivalent inductive reactance of the power supply circuit The equivalent capacitive reactance of the compensation capacitor CC , The compensation power of the electromagnetic in-phase compensator (ECPD) is obtained by solving the problem. Relationship: ; Thus compensate power That is, when The electromagnetic in-phase power compensation device (ECPD) simultaneously outputs active and reactive power to the system. The electromagnetic in-phase power compensation device (ECPD) simultaneously absorbs both active and reactive power. The time-of-use electromagnetic in-phase compensation device ECPD has no compensation; among which, the equivalent capacitive reactance of the compensation capacitor CC is... It can be designed to completely or partially cancel the inherent inductive reactance of the circuit, thereby adapting to the optimized operation requirements of the same-phase power supply system; The input excitation voltage of the rotor circuits of the first and second phase-shifting transformers in the electromagnetic in-phase compensation device (ECPD) Since the structural parameters of the first and second phase-shifting transformers are the same, the compensation voltage output of the stator circuit of the electromagnetic in-phase compensation device (ECPD) satisfies... Where k is the turns ratio constant of a single phase-shifting transformer, and θ1 and θ2 are the rotor phase shift angles of the first and second phase-shifting transformers, respectively; to ensure that the output phase of the electromagnetic in-phase compensation device ECPD is consistent with... It maintains constant phase, while also adjusting the magnitude and direction of the output compensation power, and performing decomposed control of the phase shift angles of the two rotors to optimally meet the requirements. , Where θ0 is the basic symmetry angle and Δθ is the power adjustment angle, thereby realizing the adjustment of the output voltage. Decoupling control of amplitude and phase; preferably satisfying At this time, the output compensation voltage amplitude The compensation voltage phase is always in the same frequency and phase as the output voltage of the single-phase traction transformer. S4, Calculation of rotor phase shift angle; Analysis of the relationship function between compensation power and rotor angle, from S2 and S3, the compensation power output of the electromagnetic in-phase compensation device ECPD satisfies the following relationship: ; Therefore, the power adjustment angle ∆θ is adjusted to change the compensation power; based on the optimization control objective in S2... By combining the phase shift angle decomposition formula in S3, the rotor phase shift angles θ1 and θ2 required by the first and second phase shift transformers in the electromagnetic in-phase compensation device ECPD are obtained; S5, driven independently by a servo motor, completes the phase shift angle deflection of the dual rotors and outputs the corresponding compensation power. The electromagnetic phase-shifting compensation unit (EPCU) simultaneously completes traction power transmission and negative sequence compensation tasks, realizes in-phase traction power supply, and ensures that the negative sequence voltage imbalance meets power quality requirements. The EPCU's underlying layer coordinates and controls the servo motor state by setting up, but is not limited to, compensation power control, phase angle setpoint calculation, phase angle coordinated speed control, and flexible loop control, ensuring the coordinated operation of the first and second phase-shifting transformers.

[0015] Furthermore, when a single-phase new energy power supply unit (NEPU) is also connected to the single-phase three-phase combined electromagnetic in-phase power supply system (SCE-CPS), in the system control flow S1-S5, when calculating the required output power of the electromagnetic in-phase compensation device (ECPD), the power 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.

[0016] The beneficial effects of adopting this technical solution are: This invention provides a single-phase and three-phase combined electromagnetic in-phase power supply system. Through a pure electromagnetic compensation structure, it can transform existing traction substations using conventional three-phase to two-phase transformer connections into in-phase traction power supply systems. This eliminates the phase separation at the traction substation outlet and removes the train power outage zone, enabling the traction substation to supply in-phase power to the traction network. Simultaneously, it manages negative sequence to meet grid-connected power quality requirements. Compared to traditional power electronic single-phase and three-phase in-phase power supply schemes, it eliminates the need for large-capacity power electronic converters and traction matching transformers, boasts high reliability of electromagnetic structure operation, and strong engineering applicability. It can be adapted to the transformation of existing electrified railway in-phase power supply lines and the access of new energy sources along the traction side. This invention provides a control method for a single-phase and three-phase combined electromagnetic in-phase power supply system, which can perform energy management and coordinated control among the various units of the system. During normal operation, the single-phase traction transformer side, the three-phase-to-two-phase traction transformer side, and the electromagnetic in-phase compensation device side jointly supply power to the traction bus. The single-phase traction transformer side undertakes the main traction power supply task, while the three-phase-to-two-phase traction transformer and the electromagnetic in-phase compensation device side undertake auxiliary traction power supply and negative sequence management tasks. When new energy sources are connected to the traction side, the method can perform in-phase traction power supply, efficient new energy consumption, and power quality management tasks. The electromagnetic in-phase compensation device provided by this invention is a novel railway in-phase power supply compensation device. It has a pure electromagnetic compensation structure inside and does not require any power electronic converter devices. It can independently and continuously adjust the voltage amplitude and phase between the two AC output ports by coordinating the rotor phase shift angle according to the control signal. On the one hand, it generates a voltage with the same frequency and phase as the low-voltage side of the single-phase traction transformer between the output ports. On the other hand, it can control the magnitude and direction of the compensation power in real time to achieve accurate compensation of the power quality on the grid side. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a single-phase and three-phase combined electromagnetic in-phase power supply system according to the present invention; Figure 2 This is a topology diagram of a non-isolated electromagnetic in-phase compensation device according to an embodiment of the present invention; Figure 3 This is a topology diagram of an isolated electromagnetic in-phase compensation device according to an embodiment of the present invention; Figure 4 This is a structural diagram of a single- or three-phase combined electromagnetic in-phase power supply system with a new energy power supply unit according to an embodiment of the present invention; Figure 5 This is a flowchart of a control method for a single-phase and three-phase combined electromagnetic in-phase power supply system according to the present invention. Detailed Implementation

[0018] 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.

[0019] In this embodiment, see Figure 1As shown, this invention proposes a single-phase and three-phase combined electromagnetic in-phase power supply system, comprising: a single-phase traction transformer STT, a three-phase-to-two-phase traction transformer 3 / 2TT, an electromagnetic in-phase compensation device ECPD, and a system main controller SMC; the high-voltage side winding of the single-phase traction transformer STT is connected to any two high-voltage input lines in the three-phase power grid, and port b of the low-voltage side winding of the single-phase traction transformer STT is connected to the traction bus TB circuit, and port c is connected to the rail; the three ports of the high-voltage side winding of the three-phase-to-two-phase traction transformer 3 / 2TT are respectively connected to the high-voltage input lines of the three-phase power grid, and the two ports of the low-voltage side winding are respectively connected to the input port X and port Y circuit of the electromagnetic in-phase compensation device ECPD; the output port x of the electromagnetic in-phase compensation device ECPD is connected to the traction bus TB circuit, and port y is connected to the rail; single-phase AC voltages with the same phase and frequency are generated in port b of the single-phase traction transformer STT and port x of the electromagnetic in-phase compensation device ECPD, which together power the traction bus TB, and then provide energy to the traction load TL on the power supply arm via the traction bus TB; The system's main controller (SMC) monitors the electrical quantities and operating status of the single-phase traction transformer (STT), the three-phase-to-two-phase traction transformer (3 / 2TT), the electromagnetic in-phase compensation device (ECPD), 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 during normal operation, the single-phase traction transformer (STT), the three-phase-to-two-phase traction transformer (3 / 2TT), and the electromagnetic in-phase compensation device (ECPD) jointly supply power to the traction bus. The single-phase traction transformer (STT) undertakes the main traction power supply task, while the three-phase-to-two-phase traction transformer (3 / 2TT) and the electromagnetic in-phase compensation device (ECPD) undertake the auxiliary traction power supply task and the negative sequence management task.

[0020] Preferably, the electromagnetic in-phase compensation device (ECPD) is a single-phase structure, employing either a non-isolated electromagnetic in-phase compensation device ECPD1 or an isolated electromagnetic in-phase compensation device ECPD2. The different topologies of the ECPDs enable them to independently and continuously adjust the voltage phase and amplitude between the two AC output ports based on control signals and coordinated control of the rotor phase shift angle. This generates a voltage with the same frequency and phase as the low-voltage side of the single-phase traction transformer STT between port x and port y. Furthermore, it allows for real-time control of the compensation power magnitude and direction, achieving precise compensation of the negative sequence on the grid side.

[0021] As an optimization of the above embodiments, such as Figure 2As shown, the non-isolated electromagnetic in-phase compensation device ECPD1 includes a first phase-shifting transformer RPST1, a second phase-shifting transformer RPST2, and a compensation capacitor CC. The rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in parallel, and the stator windings are connected in series. The starting ends of the stator winding and rotor winding in the first phase-shifting transformer RPST1, and the starting end of the rotor winding in the second phase-shifting transformer RPST2 are connected together at port X. The starting end of the stator winding in the second phase-shifting transformer RPST2 is connected in series with the ending end of the stator winding in the first phase-shifting transformer RPST1, and the ending end of the stator winding in the second phase-shifting transformer RPST2 is connected in series with one side of the compensation capacitor CC. The other side of the compensation capacitor CC is connected to the circuit at port x. The circuit between port Y and port y of the non-isolated electromagnetic in-phase compensation device ECPD1 is continuous.

[0022] The non-isolated electromagnetic in-phase compensation device ECPD1 preferably adopts an off-axis drive structure, wherein the rotor shaft of the first phase-shifting transformer is connected to the first rotor drive device RDD1, and the rotor is driven by the first servo motor SM1 to shift the phase angle. θ 1. Independent rotation achieves phase adjustment. The rotor shaft of the second phase-shifting transformer is connected to the second rotor drive device RDD2, and the rotor is driven by the second servo motor SM2 to shift the phase angle. θ 2. Phase adjustment is achieved through independent rotation.

[0023] As an optimization of the above embodiments, such as Figure 3 As shown, the isolated electromagnetic in-phase compensation device ECPD2 includes a first phase-shifting transformer RPST1, a second phase-shifting transformer RPST2, and a compensation capacitor CC; the rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in parallel and connected to port X and port Y respectively at the parallel connection point; the first section of the stator winding of the first phase-shifting transformer RPST1 is connected to the circuit at port x, the stator windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in series from beginning to end, the end of the stator winding of the second phase-shifting transformer RPST2 is connected in series with one side of the compensation capacitor CC, and the other side of the compensation capacitor CC is connected to the circuit at port y; The isolated electromagnetic in-phase compensation device ECPD2 preferably adopts an off-axis drive structure, with the phase shift angles of the two rotors being adjusted independently. The rotor shaft of the first phase shift transformer is connected to the first rotor drive device RDD1, and the rotor is driven by the first servo motor SM1 to rotate independently with a phase shift angle θ1 to achieve phase adjustment. The rotor shaft of the second phase shift transformer is connected to the second rotor drive device RDD2, and the rotor is driven by the second servo motor SM2 to rotate independently with a phase shift angle θ2 to achieve phase adjustment.

[0024] As an optimized solution of the above embodiments, the three-phase to two-phase traction transformer 3 / 2TT includes, but is not limited to, YNd11 connection traction transformer, YNvd connection traction transformer, V-type connection three-phase to two-phase traction transformer, impedance matching balance transformer, Scott connection two-phase to three-phase transformer, cross connection three-phase to two-phase transformer or VX connection three-phase to two-phase transformer.

[0025] As an optimization of the above embodiments, such as Figure 4 As shown, the single-phase three-phase combined electromagnetic in-phase power supply system STE-CPS can also be 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.

[0026] Preferably, 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; wherein, 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 leads out AC output ports d and e.

[0027] The DC power supply DS can be a new energy power generation unit, an energy storage unit, or a combination of new energy and energy storage. The system main controller SMC can monitor the electrical quantities and operating status of the single-phase traction transformer STT side, the three-phase to two-phase traction transformer 3 / 2TT, the electromagnetic in-phase compensation device ECPD, the single-phase new energy power supply unit NEPU, and the traction bus TB in real time, and perform energy management and coordinated control between the various units of the system 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 a single-phase and three-phase combined electromagnetic in-phase power supply system, comprising the following steps: S1, Data Acquisition and Processing: Acquire real-time operating data from the STT side of the single-phase traction transformer, the 3 / 2TT side of the three-phase to two-phase traction transformer, the ECPD side of the electromagnetic in-phase compensation device, the TB side of the traction bus, and the power grid side, and perform data analysis and processing. Using the voltage between ports b and c of the single-phase traction transformer STT as the reference voltage The output voltage between the x and y ports of the electromagnetic in-phase compensation device (ECPD) under in-phase conditions. Output compensation current Assume the output power of the single-phase traction transformer STT is... Electromagnetic in-phase compensation device (ECPD) output power Total traction load power ; S2, Demand compensation power calculation; combining the grid short-circuit capacity and the allowable value of negative sequence voltage imbalance specified in the national standard, the allowable value of negative sequence power is calculated. To meet the negative sequence requirements, based on the 3 / 2TT topology of the three-phase to two-phase traction transformer, the wiring configuration, the traction load power, and the output power of the single-phase traction transformer, the required compensation power of the electromagnetic in-phase compensation device (ECPD) is determined. This makes the apparent equivalent negative sequence power on the grid side after compensation... ;set up m This is the negative sequence power weighting coefficient generated at the point of common coupling of the power grid for a single-phase traction port. n This is the negative sequence power weighting coefficient that cancels out the in-phase compensation port at the point of common coupling of the power grid. m and n The value is determined by the winding connection, voltage phase, and current symmetry transformation characteristics of single-phase and three-phase to two-phase traction transformers, and is subject to the negative sequence index assessment requirements. If the three-phase to two-phase traction transformer is analyzed using a YNd11 connected transformer, then the apparent compensation power required by the electromagnetic in-phase compensation device (ECPD) should meet the following requirements. ; S3, Calculation of required compensation voltage; given that the three-phase to two-phase traction transformer and the electromagnetic in-phase compensation device side, as well as the single-phase traction transformer side, can be equivalent to two in-phase parallel power supplies, the compensation current is obtained. Affected by voltage difference, ,in The equivalent resistance of the power supply circuit. For the equivalent reactance of the power supply circuit, Including the equivalent inductive reactance of the power supply circuit The equivalent capacitive reactance of the compensation capacitor CC , The compensation power of the electromagnetic in-phase compensator (ECPD) is obtained by solving the problem. Relationship: ; Thus compensate power That is, when The electromagnetic in-phase power compensation device (ECPD) simultaneously outputs active and reactive power to the system. The electromagnetic in-phase power compensation device (ECPD) simultaneously absorbs both active and reactive power. The time-of-use electromagnetic in-phase compensation device ECPD has no compensation; among which, the equivalent capacitive reactance of the compensation capacitor CC is... It can be designed to completely or partially cancel the inherent inductive reactance of the circuit, thereby adapting to the optimized operation requirements of the same-phase power supply system; The input excitation voltage of the rotor circuits of the first and second phase-shifting transformers in the electromagnetic in-phase compensation device (ECPD) Since the structural parameters of the first and second phase-shifting transformers are the same, the compensation voltage output of the stator circuit of the electromagnetic in-phase compensation device (ECPD) satisfies... ,in Here, θ1 and θ2 are the turns ratio constants of a single phase-shifting transformer, and θ1 and θ2 are the rotor phase shift angles of the first and second phase-shifting transformers, respectively; to ensure that the output phase of the electromagnetic in-phase compensation device ECPD is consistent with... It maintains constant phase, while also adjusting the magnitude and direction of the output compensation power, and performing decomposed control of the phase shift angles of the two rotors to optimally meet the requirements. , Where θ0 is the basic symmetry angle and Δθ is the power adjustment angle, thereby realizing the adjustment of the output voltage. Decoupling control of amplitude and phase; preferably satisfying At this time, the output compensation voltage amplitude The compensation voltage phase is always in the same frequency and phase as the output voltage of the single-phase traction transformer. S4, Calculation of rotor phase shift angle; Analysis of the relationship function between compensation power and rotor angle, from S2 and S3, the compensation power output of the electromagnetic in-phase compensation device ECPD satisfies the following relationship: S4, Calculation of rotor phase shift angle; Analysis of the relationship function between compensation power and rotor angle, from S2 and S3, the compensation power output of the electromagnetic in-phase compensation device ECPD satisfies the following relationship: ; Therefore, the power adjustment angle ∆θ is adjusted to change the compensation power; based on the optimization control objective in S2... By combining the phase shift angle decomposition formula in S3, the required rotor phase shift angles of the first and second phase shift transformers in the electromagnetic in-phase compensation device ECPD are obtained. θ 1 and θ 2; S5, driven independently by a servo motor, completes the phase shift angle deflection of the dual rotors and outputs the corresponding compensation power. The electromagnetic phase-shifting compensation unit (EPCU) simultaneously completes traction power transmission and negative sequence compensation tasks, realizes in-phase traction power supply, and ensures that the negative sequence voltage imbalance meets power quality requirements. The EPCU's underlying layer coordinates and controls the servo motor state by setting up, but is not limited to, compensation power control, phase angle setpoint calculation, phase angle coordinated speed control, and flexible loop control, ensuring the coordinated operation of the first and second phase-shifting transformers.

[0029] As an optimization of the above embodiment, when a single-phase new energy power supply unit (NEPU) is also connected to the single-phase three-phase combined electromagnetic in-phase power supply system (SCE-CPS), in the system control flow S1-S5, when calculating the required output power of the electromagnetic in-phase compensation device (ECPD), the power 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] 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. A single-phase / three-phase combined electromagnetic in-phase power supply system, characterized in that, include: Single-phase traction transformer STT, three-phase to two-phase traction transformer 3 / 2TT, electromagnetic in-phase compensation device ECPD, and system main controller SMC; The high-voltage side winding of the single-phase traction transformer STT is connected to any two high-voltage input lines in the three-phase power grid, and the port b of the low-voltage side winding is connected to the traction bus TB circuit, and the port c is connected to the rail. The three-phase to two-phase traction transformer 3 / 2TT has its high-voltage side windings connected to the three-phase power grid high-voltage input lines at its three ports, and its low-voltage side windings connected to the input ports X and Y of the electromagnetic in-phase compensation device ECPD at its two ports. The output port x of the electromagnetic in-phase compensation device ECPD is connected to the traction bus TB circuit, and the port y is connected to the rail; the single-phase traction transformer STT port b and the electromagnetic in-phase compensation device ECPD port x generate single-phase AC voltages with the same phase and frequency, which together power the traction bus TB, and then power the traction load TL on the power supply arm through the traction bus TB. The system's main controller (SMC) monitors the electrical quantities and operating status of the single-phase traction transformer (STT), the three-phase-to-two-phase traction transformer (3 / 2TT), the electromagnetic in-phase compensation device (ECPD), 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 during normal operation, the single-phase traction transformer (STT), the three-phase-to-two-phase traction transformer (3 / 2TT), and the electromagnetic in-phase compensation device (ECPD) jointly supply power to the traction bus. The single-phase traction transformer (STT) undertakes the main traction power supply task, while the three-phase-to-two-phase traction transformer (3 / 2TT) and the electromagnetic in-phase compensation device (ECPD) undertake the auxiliary traction power supply task and the negative sequence management task.

2. The single-phase / three-phase combined electromagnetic in-phase power supply system according to claim 1, characterized in that, The electromagnetic in-phase compensation device (ECPD) is a single-phase structure, employing either a non-isolated electromagnetic in-phase compensation device (ECPD1) or an isolated electromagnetic in-phase compensation device (ECPD2). These ECPDs with different topologies can, based on control signals and through coordinated control of the rotor phase shift angle, independently and continuously adjust the voltage phase and amplitude between the two AC output ports. On one hand, they generate a voltage between port x and port y with the same frequency and phase as the low-voltage side of the single-phase traction transformer (STT). On the other hand, they can control the magnitude and direction of the compensation power in real time, achieving precise compensation of the negative sequence on the grid side.

3. A single-phase / three-phase combined electromagnetic in-phase power supply system according to claim 2, characterized in that, The non-isolated electromagnetic in-phase compensation device ECPD1 includes a first phase-shifting transformer RPST1, a second phase-shifting transformer RPST2, and a compensation capacitor CC. The rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in parallel, and the stator windings are connected in series. The starting ends of the stator winding and rotor winding in the first phase-shifting transformer RPST1, and the starting end of the rotor winding in the second phase-shifting transformer RPST2 are connected together at port X. The starting end of the stator winding in the second phase-shifting transformer RPST2 is connected in series with the ending end of the stator winding in the first phase-shifting transformer RPST1, and the ending end of the stator winding in the second phase-shifting transformer RPST2 is connected in series with one side of the compensation capacitor CC. The other side of the compensation capacitor CC is connected to the circuit at port x. The circuit between ports Y and y of the non-isolated electromagnetic in-phase compensation device ECPD1 is continuous.

4. A single-phase / three-phase combined electromagnetic in-phase power supply system according to claim 3, characterized in that, The non-isolated electromagnetic in-phase compensation device ECPD1 adopts an off-axis drive structure, wherein the rotor shaft of the first phase-shifting transformer is connected to the first rotor drive device RDD1, and the rotor is driven by the first servo motor SM1 to rotate independently with a phase shift angle θ1 to achieve phase adjustment. The rotor shaft of the second phase-shifting transformer is connected to the second rotor drive device RDD2, and the rotor is driven by the second servo motor SM2 to rotate independently with a phase shift angle θ2 to achieve phase adjustment.

5. A single-phase / three-phase combined electromagnetic in-phase power supply system according to claim 2, characterized in that, The isolated electromagnetic in-phase compensation device ECPD2 includes a first phase-shifting transformer RPST1, a second phase-shifting transformer RPST2, and a compensation capacitor CC. The rotor windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in parallel and connected to port X and port Y at the parallel connection point, respectively. The first section of the stator winding of the first phase-shifting transformer RPST1 is connected to the circuit at port x. The stator windings of the first phase-shifting transformer RPST1 and the second phase-shifting transformer RPST2 are connected in series from start to finish. The end of the stator winding of the second phase-shifting transformer RPST2 is then connected in series with one side of the compensation capacitor CC. The other side of the compensation capacitor CC is connected to the circuit at port y.

6. A single-phase / three-phase combined electromagnetic in-phase power supply system according to claim 5, characterized in that, The isolated electromagnetic in-phase compensation device ECPD2 adopts an off-axis drive structure, with the phase shift angles of the two rotors being adjusted independently. The rotor shaft of the first phase shift transformer is connected to the first rotor drive device RDD1, and the rotor is driven by the first servo motor SM1 to rotate independently at a phase shift angle θ1 to achieve phase adjustment. The rotor shaft of the second phase shift transformer is connected to the second rotor drive device RDD2, and the rotor is driven by the second servo motor SM2 to rotate independently at a phase shift angle θ2 to achieve phase adjustment.

7. A single-phase / three-phase combined electromagnetic in-phase power supply system according to claim 1, characterized in that, The three-phase to two-phase traction transformer 3 / 2TT includes, but is not limited to, YNd11 connection traction transformer, YNvd connection traction transformer, V-type connection three-phase to two-phase traction transformer, impedance matching balance transformer, Scott connection two-phase to three-phase transformer, cross connection three-phase to two-phase transformer or VX connection three-phase to two-phase transformer.

8. A single-phase / three-phase combined electromagnetic in-phase power supply system according to any one of claims 1-7, characterized in that, It 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 leads out AC output ports d and e.

9. A control method for a single-phase / three-phase combined electromagnetic in-phase power supply system, characterized in that, A single-phase and three-phase combined electromagnetic in-phase power supply system includes: a single-phase traction transformer STT, a three-phase-to-two-phase traction transformer 3 / 2TT, an electromagnetic in-phase compensation device ECPD, and a system main controller SMC. The high-voltage side winding of the single-phase traction transformer STT is connected to two high-voltage input lines of a three-phase power grid. Port b of the low-voltage side winding of the single-phase traction transformer STT is connected to the traction busbar TB circuit, and port c is connected to the rail. The three ports of the high-voltage side winding of the three-phase-to-two-phase traction transformer 3 / 2TT are respectively connected to the high-voltage input lines of the three-phase power grid, and the two ports of the low-voltage side winding are respectively connected to the electromagnetic in-phase compensation device ECPD. The input ports X and Y are connected by circuits; the output port x of the electromagnetic in-phase compensation device ECPD is connected to the traction bus TB circuit, and port y is connected to the rail; the single-phase traction transformer STT port b and the electromagnetic in-phase compensation device ECPD port x generate single-phase AC voltages with the same phase and frequency, which together power the traction bus TB, and then provide energy to the traction load TL on the power supply arm via the traction bus TB; the system main controller SMC is connected to the single-phase traction transformer STT, the three-phase-to-two-phase traction transformer 3 / 2TT, the electromagnetic in-phase compensation device ECPD, and the traction bus TB signal. The system control process includes the following steps: S1, Data Acquisition and Processing: Acquire real-time operating data from the STT side of the single-phase traction transformer, the 3 / 2TT side of the three-phase to two-phase traction transformer, the ECPD side of the electromagnetic in-phase compensation device, the TB side of the traction bus, and the power grid side, and perform data analysis and processing. Using the voltage between ports b and c of the single-phase traction transformer STT as the reference voltage The output voltage between the x and y ports of the electromagnetic in-phase compensation device (ECPD) under in-phase conditions. Output compensation current Assume the output power of the single-phase traction transformer STT is... Electromagnetic in-phase compensation device (ECPD) output power Total traction load power ; S2, Demand compensation power calculation; combining the grid short-circuit capacity and the allowable value of negative sequence voltage imbalance specified in the national standard, the allowable value of negative sequence power is calculated. To meet the negative sequence requirements, based on the 3 / 2TT topology of the three-phase to two-phase traction transformer, the wiring configuration, the traction load power, and the output power of the single-phase traction transformer, the required compensation power of the electromagnetic in-phase compensation device (ECPD) is determined. This makes the apparent equivalent negative sequence power on the grid side after compensation... ;set up m This is the negative sequence power weighting coefficient generated at the point of common coupling of the power grid for a single-phase traction port. n This is the negative sequence power weighting coefficient that cancels out the in-phase compensation port at the point of common coupling of the power grid. m and n The value is determined by the winding connection, voltage phase, and current symmetry transformation characteristics of single-phase and three-phase to two-phase traction transformers, and is subject to the negative sequence index assessment requirements. If the three-phase to two-phase traction transformer is analyzed using a YNd11 connected transformer, then the apparent compensation power required by the electromagnetic in-phase compensation device (ECPD) should meet the following requirements. ; S3, Calculation of required compensation voltage; given that the three-phase to two-phase traction transformer and the electromagnetic in-phase compensation device side, as well as the single-phase traction transformer side, can be equivalent to two in-phase parallel power supplies, the compensation current is obtained. Affected by voltage difference, ,in The equivalent resistance of the power supply circuit. For the equivalent reactance of the power supply circuit, Including the equivalent inductive reactance of the power supply circuit The equivalent capacitive reactance of the compensation capacitor CC , The compensation power of the electromagnetic in-phase compensator (ECPD) is obtained by solving the problem. Relationship: ; Thus compensate power That is, when The electromagnetic in-phase power compensation device (ECPD) simultaneously outputs active and reactive power to the system. The electromagnetic in-phase power compensation device (ECPD) simultaneously absorbs both active and reactive power. The time-of-use electromagnetic in-phase compensation device ECPD has no compensation; among which, the equivalent capacitive reactance of the compensation capacitor CC is... It can be designed to completely or partially cancel the inherent inductive reactance of the circuit, thereby adapting to the optimized operation requirements of the same-phase power supply system; The input excitation voltage of the rotor circuits of the first and second phase-shifting transformers in the electromagnetic in-phase compensation device (ECPD) Since the structural parameters of the first and second phase-shifting transformers are the same, the compensation voltage output of the stator circuit of the electromagnetic in-phase compensation device (ECPD) satisfies... Where k is the turns ratio constant of a single phase-shifting transformer, and θ1 and θ2 are the rotor phase shift angles of the first and second phase-shifting transformers, respectively; to ensure that the output phase of the electromagnetic in-phase compensation device ECPD is consistent with... It maintains constant phase, while also adjusting the magnitude and direction of the output compensation power, and performing decomposed control of the phase shift angles of the two rotors to optimally meet the requirements. , Where θ0 is the basic symmetry angle and Δθ is the power adjustment angle, thereby realizing the adjustment of the output voltage. Decoupling control of amplitude and phase; optimally satisfying At this time, the output compensation voltage amplitude The compensation voltage phase is always in the same frequency and phase as the output voltage of the single-phase traction transformer. S4, Calculation of rotor phase shift angle; Analysis of the relationship function between compensation power and rotor angle, from S2 and S3, the compensation power output of the electromagnetic in-phase compensation device ECPD satisfies the following relationship: ； Therefore, the power adjustment angle ∆θ is adjusted to change the compensation power; based on the optimization control objective in S2... By combining the phase shift angle decomposition formula in S3, the required rotor phase shift angles of the first and second phase shift transformers in the electromagnetic in-phase compensation device ECPD are obtained. θ 1 and θ 2; S5, driven independently by a servo motor, completes the phase shift angle deflection of the dual rotors and outputs the corresponding compensation power. The electromagnetic phase-shifting compensation unit (EPCU) simultaneously completes traction power transmission and negative sequence compensation tasks, realizes in-phase traction power supply, and ensures that the negative sequence voltage imbalance meets power quality requirements. The EPCU's underlying layer coordinates and controls the servo motor state by setting up, but is not limited to, compensation power control, phase angle setpoint calculation, phase angle coordinated speed control, and flexible loop control, ensuring the coordinated operation of the first and second phase-shifting transformers.

10. The control method for a single-phase / three-phase combined electromagnetic in-phase power supply system according to claim 9, characterized in that, When a single-phase new energy power supply unit (NEPU) is also connected to the single-phase three-phase combined electromagnetic in-phase power supply system (SCE-CPS), in the system control flow S1-S5, when calculating the required output power of the electromagnetic in-phase compensation device (ECPD), the power 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.

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