A traction grid interconnection system and a control method and device thereof

Abstract

This invention discloses a traction network interconnection system and its control method and equipment, belonging to the field of rail transit. When the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power can be determined based on the amount by which the DC traction network voltage exceeds the specified DC voltage range and the load conditions of the AC traction network. Conversely, when the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power can be determined based on the adjustable range of the DC traction network voltage within the specified DC voltage range and the load conditions of the AC traction network. This not only ensures the voltage reliability of the DC traction network but also assists in absorbing regenerative energy from the AC traction network or provides power compensation for the AC traction network within its capacity. Thus, it simultaneously considers the voltage reliability of the DC traction network, the timely recovery of regenerative energy, and the power compensation for the AC traction network.

Description

Technical Field

[0001] This invention relates to the field of rail transit, and in particular to a traction network interconnection system and its control method and equipment. Background Technology

[0002] In the field of rail transit, the power supply system of the traction network includes AC and DC systems. The power exchange between the two power supply systems can be achieved through the traction network interconnection system. However, there is a lack of a mature control method for the traction network interconnection system in the relevant technologies, which makes it difficult to balance the voltage reliability of the DC traction network, the timely recovery of regenerative energy, and the power compensation for the AC traction network. Summary of the Invention

[0003] The purpose of this invention is to provide a traction network interconnection system and its control method and equipment. When the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power can be determined based on the amount by which the DC traction network voltage exceeds the specified DC voltage range and the load conditions of the AC traction network. Conversely, when the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power can be determined based on the adjustable range of the DC traction network voltage within the specified DC voltage range and the load conditions of the AC traction network. This not only ensures the voltage reliability of the DC traction network but also assists in absorbing regenerative energy from the AC traction network or provides power compensation for the AC traction network within its capacity. Thus, it simultaneously considers the voltage reliability of the DC traction network, the timely recovery of regenerative energy, and the power compensation for the AC traction network.

[0004] To address the aforementioned technical problems, this invention provides a control method for a track interconnection system, applied to a controller of the track interconnection system. The power converter in the track interconnection system is connected to both an AC traction network and a DC traction network to achieve AC / DC power conversion, comprising: If the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the amount by which the DC traction network voltage value exceeds the specified DC voltage range and the load conditions of the AC traction network, so that the voltage value of the DC traction network returns to the specified DC voltage range; the load conditions include traction conditions and regenerative conditions. If the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the adjustable range of the DC traction network voltage value within the specified DC voltage range and the load conditions of the AC traction network, so as to absorb or compensate the AC traction network for electrical energy. The power converter in the control track interconnection system performs power migration according to the target transmission power.

[0005] On the other hand, if the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the amount by which the DC traction network voltage exceeds the specified DC voltage range and the load conditions of the AC traction network, including: If the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is regenerative, the first transmission power is taken as the target transmission power; the first transmission power is: the transmission power determined by taking the voltage value of the DC traction network returning to the upper limit of the DC specified voltage range as the target. If the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is the traction condition, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network; the second transmission power is the transmission power determined with the voltage value of the DC traction network returning to the lower limit of the DC specified voltage range as the target. If the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is regenerative, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network. If the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is the traction condition, the second transmission power will be used as the target transmission power.

[0006] On the other hand, if the voltage value of the DC traction network is greater than the upper limit of the specified DC voltage range, and the load condition of the AC traction network is the traction condition, determining the target transmission power based on the first transmission power, the second transmission power, and the load power of the AC traction network includes: If the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is the traction condition, determine whether the first transmission power can meet the load power of the AC traction network. If possible, the first transmission power shall be used as the target transmission power; If not, the lower of the absolute values ​​of the second transmission power and the load power of the AC traction network shall be used as the target transmission power.

[0007] On the other hand, if the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is regenerative, determining the target transmission power based on the first transmission power, the second transmission power, and the load power of the AC traction network includes: If the voltage value of the DC traction network is less than the lower limit of the DC specified voltage range, and the load condition of the AC traction network is regenerative, determine whether the load power of the AC traction network can meet the second transmission power. If possible, the lower of the first transmission power and the load power of the AC traction network shall be used as the target transmission power. If not, then the second transmission power will be used as the target transmission power.

[0008] On the other hand, the process of determining the first transmission power includes: The first transmission power is determined by the first relational expression; The process of determining the second transmission power includes: The second transmission power is determined by the second relational expression; The first relation includes: ; The second relation includes: ; in, This is the upper limit of the specified DC voltage range. This is the lower limit of the specified DC voltage range. U 3 represents the voltage value of the DC traction network. R dc This is the equivalent impedance from the DC traction network load to the traction substation.

[0009] On the other hand, if the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the adjustable range of the DC traction network voltage value within the specified DC voltage range and the load conditions of the AC traction network, including: If the voltage value of the DC traction network does not exceed the specified DC voltage range, and the load condition of the AC traction network is regenerative, the lower of the absolute values ​​of the first transmission power and the load power of the AC traction network shall be used as the target transmission power. If the voltage value of the DC traction network does not exceed the specified DC voltage range, and the load condition of the AC traction network is the traction condition, the lower of the absolute values ​​of the second transmission power and the load power of the AC traction network shall be taken as the target transmission power.

[0010] On the other hand, after the power converter in the control track interconnection system performs power migration according to the target transmission power, the control method of the track interconnection system further includes: Determine whether the voltage value of the AC traction network exceeds the specified AC voltage range; If it exceeds the limit, the target reactive power of the AC traction network shall be determined based on the amount by which the voltage value of the AC traction network exceeds the specified AC voltage range. The power converter in the control track interconnection system performs reactive power compensation on the AC traction network according to the target reactive power.

[0011] To address the aforementioned technical problems, the present invention also provides a track line interconnection system, comprising: Power converters that are connected to AC traction networks and DC traction networks respectively; The detection module is used to detect the electrical energy parameters of the DC traction network and the AC traction network; A controller is used to implement the steps of the control method for the track line interconnection system as described above.

[0012] On the other hand, the power converter includes: The first sub-power converter is connected to the first AC traction network on its AC side and is used to perform power conversion between the first AC traction network and the DC transformer. The second sub-power converter is connected to the second AC traction network on its AC side and is used to perform power conversion between the second AC traction network and the DC transformer. The DC transformer has its first end connected to the DC side of the first sub-power converter and the DC side of the second sub-power converter, and its second end connected to the DC traction network for DC voltage regulation.

[0013] To address the aforementioned technical problems, the present invention also provides a control device for a track interconnection system, comprising: Memory, used to store computer programs; A processor is used to execute the computer program to implement the steps of the control method for the track interconnection system as described above.

[0014] Beneficial Effects: This invention provides a control method for a track interconnection system. Considering that the voltage reliability of the DC traction network is crucial, but the DC traction network can also assist in absorbing regenerative energy from the AC traction network or provide power compensation for the AC traction network, this invention determines the target transmission power based on the amount by which the DC traction network voltage exceeds the specified DC voltage range and the load conditions of the AC traction network when the DC traction network voltage exceeds the specified DC voltage range. Conversely, when the DC traction network voltage does not exceed the specified DC voltage range, the target transmission power is determined based on the adjustable range of the DC traction network voltage within the specified DC voltage range and the load conditions of the AC traction network. This not only ensures the voltage reliability of the DC traction network but also assists in absorbing regenerative energy from the AC traction network or provides power compensation for the AC traction network within its capacity, thus simultaneously considering the voltage reliability of the DC traction network, the timely recovery of regenerative energy, and the power compensation for the AC traction network.

[0015] The present invention also provides a track line interconnection system and its control device and equipment, which have the same beneficial effects as the control method of the track line interconnection system mentioned above. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the relevant technologies and the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart illustrating a control method for a track interconnection system provided by the present invention; Figure 2 A schematic diagram of the structure of a track line interconnection system provided by the present invention; Figure 3 A flowchart illustrating another control method for a track interconnection system provided by the present invention; Figure 4 This is a schematic diagram of the structure of a control device for a track interconnection system provided by the present invention. Detailed Implementation

[0018] The core of this invention is to provide a traction network interconnection system and its control method and equipment. When the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power can be determined based on the amount by which the DC traction network voltage exceeds the specified DC voltage range and the load conditions of the AC traction network. Conversely, when the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power can be determined based on the adjustable range of the DC traction network voltage within the specified DC voltage range and the load conditions of the AC traction network. This not only ensures the voltage reliability of the DC traction network but also assists in absorbing regenerative energy from the AC traction network or provides power compensation for the AC traction network within its capacity. Thus, it simultaneously considers the voltage reliability of the DC traction network, the timely recovery of regenerative energy, and the power compensation for the AC traction network.

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please refer to Figure 1 , Figure 1This invention provides a flowchart illustrating a control method for a track interconnection system. This control method is applied to the controller of the track interconnection system. The power converter in the track interconnection system is connected to both the AC traction network and the DC traction network to achieve AC / DC power conversion, including: S101: If the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network shall be determined based on the amount by which the DC traction network voltage value exceeds the specified DC voltage range and the load conditions of the AC traction network, so that the voltage value of the DC traction network returns to the specified DC voltage range; the load conditions include traction conditions and regenerative conditions. Specifically, considering the technical problems mentioned above, and taking into account the critical importance of the voltage reliability of the DC traction network, while the DC traction network can also assist in absorbing regenerative energy from the AC traction network or provide power compensation for the AC traction network, this embodiment of the invention aims to achieve the primary objective of ensuring that the voltage value of the DC traction network is within the specified DC voltage range. Power transfer is then performed between the AC and DC traction networks in the track interconnection system. Therefore, in this step, if the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power between the AC and DC traction networks is determined based on the amount by which the DC traction network's voltage value exceeds the specified DC voltage range and the load conditions of the AC traction network (including traction and regenerative conditions). This ensures that the voltage value of the DC traction network returns to the specified DC voltage range, thereby guaranteeing the voltage reliability of the DC traction network.

[0021] The specified DC voltage range can be set independently, and this embodiment of the invention does not limit it.

[0022] S102: If the voltage value of the DC traction network does not exceed the specified DC voltage range, determine the target transmission power between the AC traction network and the DC traction network based on the adjustable range of the DC traction network voltage value within the specified DC voltage range and the load conditions of the AC traction network, so as to absorb or compensate the AC traction network for electrical energy. Specifically, considering that even if the voltage value of the DC traction network does not exceed the specified DC voltage range, theoretically power transfer can still be performed between the AC traction network and the DC traction network to absorb or compensate for the AC traction network's electrical energy, in this step, if the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the adjustable range of the DC traction network's voltage value within the specified DC voltage range and the load conditions of the AC traction network, so as to absorb or compensate for the AC traction network's electrical energy.

[0023] S103: Controls the power converter in the track interconnection system to perform power migration according to the target transmission power.

[0024] Specifically, after determining the target transmission power based on the voltage value of the DC traction network, the power converter in the track interconnection system can be controlled to perform power migration according to the target transmission power. This ensures that the voltage value of the DC traction network is within the specified DC voltage range, and also allows for energy absorption or compensation of the AC traction network. Thus, it simultaneously ensures the voltage reliability of the DC traction network, timely recovery of regenerative energy, and power compensation of the AC traction network.

[0025] This invention provides a control method for a track interconnection system. Considering the critical importance of DC traction network voltage reliability, but also the fact that the DC traction network can assist in absorbing regenerative energy from the AC traction network or providing power compensation for the AC traction network, this invention determines the target transmission power based on the amount by which the DC traction network voltage exceeds the specified DC voltage range and the load conditions of the AC traction network when the DC traction network voltage exceeds the specified range. Conversely, when the DC traction network voltage does not exceed the specified range, the target transmission power is determined based on the adjustable range of the DC traction network voltage within the specified range and the load conditions of the AC traction network. This not only ensures the voltage reliability of the DC traction network but also allows for the absorption of regenerative energy from the AC traction network or power compensation within its capacity, thus simultaneously addressing the voltage reliability of the DC traction network, the timely recovery of regenerative energy, and power compensation for the AC traction network.

[0026] Based on the above embodiments: As an optional embodiment, if the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the amount by which the DC traction network voltage exceeds the specified DC voltage range and the load conditions of the AC traction network, including: If the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is regenerative, the first transmission power is taken as the target transmission power; the first transmission power is: the transmission power determined by taking the voltage value of the DC traction network returning to the upper limit of the DC specified voltage range as the target. If the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is the traction condition, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network; the second transmission power is the transmission power determined with the voltage value of the DC traction network returning to the lower limit of the DC specified voltage range as the target. If the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is regenerative, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network. If the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is the traction condition, the second transmission power will be used as the target transmission power.

[0027] Specifically, considering that the voltage value of the DC traction network exceeding the specified DC voltage range includes two cases: "greater than the upper limit and less than the lower limit", and that the determination of the target transmission power is also related to the traction conditions (regenerative conditions and traction conditions) of the AC traction network, in this embodiment of the invention, (1) if the voltage value of the DC traction network is greater than the upper limit of the specified DC voltage range, and the load condition of the AC traction network is regenerative, the first transmission power (the transmission power determined by the DC traction network voltage value returning to the upper limit of the specified DC voltage range) is used as the target transmission power, thereby using the DC traction network exceeding the upper limit as the target transmission power; (2) if the voltage value of the DC traction network is greater than the specified DC voltage range, the first transmission power (the transmission power determined by the DC traction network voltage value returning to the upper limit of the specified DC voltage range) is used as the target transmission power; (2) If the upper limit value is less than the lower limit value of the DC specified voltage range and the load condition of the AC traction network is the traction condition, the target transmission power is determined based on the first transmission power, the second transmission power (the transmission power determined by the lower limit value of the DC specified voltage range when the DC traction network voltage value returns to the DC specified voltage range) and the load power of the AC traction network; (3) If the DC traction network voltage value is less than the lower limit value of the DC specified voltage range and the load condition of the AC traction network is the regenerative condition, the target transmission power is determined based on the first transmission power, the second transmission power and the load power of the AC traction network; (4) If the DC traction network voltage value is less than the lower limit value of the DC specified voltage range and the load condition of the AC traction network is the traction condition, the second transmission power is taken as the target transmission power.

[0028] Specifically, through the embodiments of the present invention, a suitable target traction power can be determined by combining the specific exceedance of the DC traction network relative to the specified DC voltage range, the load conditions of the AC traction network, and the load power of the AC traction network. This can further improve the reliability of both the DC and AC traction networks while ensuring that the voltage of the DC traction network is within the specified DC voltage range.

[0029] As an optional embodiment, if the voltage value of the DC traction network is greater than the upper limit of the specified DC voltage range, and the load condition of the AC traction network is traction condition, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network, including: If the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is the traction condition, determine whether the first transmission power can meet the load power of the AC traction network. If possible, the first transmission power shall be used as the target transmission power; If not, the lower of the absolute values ​​of the second transmission power and the load power of the AC traction network shall be used as the target transmission power.

[0030] Specifically, considering that when the voltage of the DC traction network is greater than the upper limit of the specified DC voltage range and the AC traction network is in traction mode, whether the first transmission power can meet the load power of the AC traction network is of reference significance for the specific value of the target transmission power. Therefore, in this embodiment of the invention, it can be determined whether the first transmission power can meet the load power of the AC traction network in this case. If it can, the first transmission power is taken as the target transmission power, thereby meeting the load power of the AC traction network through the first transmission power. If it cannot, the lower of the absolute values ​​of the second transmission power and the load power of the AC traction network is taken as the target transmission power, thereby minimizing the power migration to the DC traction network while meeting the load power of the AC traction network.

[0031] Of course, in addition to this specific form, "if the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is the traction condition, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network" can also be in other forms, and the embodiments of the present invention are not limited here.

[0032] As an optional embodiment, if the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is regenerative, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network, including: If the voltage value of the DC traction network is less than the lower limit of the DC specified voltage range, and the load condition of the AC traction network is regenerative, determine whether the load power of the AC traction network can meet the second transmission power. If possible, the lower of the first transmission power and the load power of the AC traction network shall be used as the target transmission power. If not, then the second transmission power will be used as the target transmission power.

[0033] Specifically, considering that "the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is regenerative," whether the load power of the AC traction network can meet the second transmission power is of great significance for determining the target transmission power. Therefore, in this embodiment of the invention, if the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is regenerative, it is determined whether the load power of the AC traction network can meet the second transmission power. If it can, the lower of the first transmission power and the load power of the AC traction network is taken as the target transmission power, so as to supplement the voltage value of the DC traction network to the upper limit through the regenerative energy of the AC traction network as much as possible. If it cannot, the second transmission power is taken as the target transmission power so as to supplement the power of the DC traction network through all the regenerative energy of the AC traction network.

[0034] Of course, in addition to this form, "if the voltage value of the DC traction network is less than the lower limit of the DC specified voltage range, and the load condition of the AC traction network is a regenerative condition, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network" can also be in other forms, and this embodiment of the invention does not limit them here.

[0035] As an optional embodiment, the process of determining the first transmission power includes: The first transmission power is determined by the first relational expression; The process of determining the second transmission power includes: The second transmission power is determined by the second relational expression; The first relation includes: ; The second relation includes: ; in, This is the upper limit of the specified DC voltage range. This is the lower limit of the specified DC voltage range. U 3 represents the voltage value of the DC traction network. R dc This is the equivalent impedance from the DC traction network load to the traction substation.

[0036] Specifically, the first transmission power and the second transmission power can be determined efficiently and accurately through the first and second relational expressions in the embodiments of the present invention.

[0037] Of course, in addition to this specific method, other methods can be used to determine the first transmission power and the second transmission power, and the embodiments of the present invention are not limited here.

[0038] As an optional embodiment, if the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the adjustable range of the DC traction network voltage value within the specified DC voltage range and the load conditions of the AC traction network, including: If the voltage value of the DC traction network does not exceed the specified DC voltage range, and the load condition of the AC traction network is regenerative, the lower of the absolute values ​​of the first transmission power and the load power of the AC traction network shall be used as the target transmission power. If the voltage value of the DC traction network does not exceed the specified DC voltage range, and the load condition of the AC traction network is the traction condition, the lower of the absolute values ​​of the second transmission power and the load power of the AC traction network shall be taken as the target transmission power.

[0039] Specifically, considering that when the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power can be determined by referring to the load conditions of the AC traction network. Therefore, in this embodiment of the invention, if the voltage value of the DC traction network does not exceed the specified DC voltage range and the load conditions of the AC traction network are regenerative, the lower of the absolute values ​​of the first transmission power and the load power of the AC traction network is taken as the target transmission power to prevent the voltage value of the DC traction network from exceeding the upper limit when absorbing the regenerative capacity of the AC traction network; if the voltage value of the DC traction network does not exceed the specified DC voltage range and the load conditions of the AC traction network are traction conditions, the lower of the absolute values ​​of the second transmission power and the load power of the AC traction network is taken as the target transmission power to prevent the voltage value from falling below the lower limit when the DC traction network supplements power to the AC traction network.

[0040] Of course, in addition to this specific form, "if the voltage value of the DC traction network does not exceed the DC specified voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the adjustable range of the DC traction network voltage value within the DC specified voltage range and the load conditions of the AC traction network" can also be in other forms, and this embodiment of the invention does not limit it here.

[0041] As an optional embodiment, after controlling the power converter in the track interconnection system to perform power migration according to the target transmission power, the control method of the track interconnection system further includes: Determine whether the voltage value of the AC traction network exceeds the specified AC voltage range; If it exceeds the limit, the target reactive power of the AC traction network shall be determined based on the amount by which the voltage value of the AC traction network exceeds the specified AC voltage range. The power converter in the control track interconnection system performs reactive power compensation on the AC traction network according to the target reactive power.

[0042] Specifically, considering that after the aforementioned power migration process, the AC traction network may be affected, resulting in a voltage value exceeding the specified AC voltage range, and since the power converter in the track interconnection system itself has reactive power compensation capabilities, this embodiment of the invention can determine whether the voltage value of the AC traction network exceeds the specified AC voltage range after controlling the power converter in the track interconnection system to perform power migration according to the target transmission power. If it does, the target reactive power of the AC traction network is determined based on the amount by which the voltage value of the AC traction network exceeds the specified AC voltage range; and the power converter in the track interconnection system is controlled to perform reactive power compensation on the AC traction network according to the target reactive power.

[0043] Specifically, if the voltage of the AC traction network is higher than the upper limit, the converter in the power converter can be controlled to absorb inductive reactive power; if the voltage of the AC traction network is lower than the lower limit, the converter in the power converter can be controlled to absorb capacitive reactive power.

[0044] To address the aforementioned technical problems, the present invention also provides a track line interconnection system, comprising: Power converters that are connected to AC traction networks and DC traction networks respectively; The detection module is used to detect the electrical energy parameters of the DC traction network and the AC traction network; A controller is used to implement the steps of the control method for the track interconnection system as described in the foregoing embodiments.

[0045] As an optional embodiment, the power converter includes: The first sub-power converter is connected to the first AC traction network on its AC side and is used to perform power conversion between the first AC traction network and the DC transformer. The second sub-power converter is connected to the second AC traction network on its AC side and is used to perform power conversion between the second AC traction network and the DC transformer. The DC transformer has its first end connected to the DC side of the first sub-power converter and the DC side of the second sub-power converter, and its second end connected to the DC traction network for DC voltage regulation.

[0046] Specifically, for a better explanation of the embodiments of the present invention, please refer to... Figure 2 , Figure 2 This is a schematic diagram of a track line interconnection system provided by the present invention. The track line interconnection system connects two AC traction networks. When the DC traction network needs to output or receive power, the two AC traction networks can equally divide the target transmission power. For example, when the DC traction network needs to output power, the two AC traction networks can each receive half of the target transmission power. Figure 2Specifically, it includes the first AC traction substation ACTS1, the second AC traction substation ACTS2, the DC traction substation DCTS, the sectioning substation, and the measurement and control system MCS. The sectioning substation includes a three-port power converter TPPC; the three-port power converter TPPC includes a first step-down transformer MT1, a second step-down transformer MT2, a first converter CO1, a second converter CO2, and a DC-DC converter; the primary side of the first step-down transformer MT1 is connected to the first AC traction network OSC1 and the AC rail R, and the secondary side is connected to the AC side of the first converter CO1; the primary side of the second step-down transformer MT2 is connected to the second AC traction network OCS2 and the AC rail R, and the secondary side is connected to the AC side of the second converter CO2; the DC side of the first converter CO1 is connected to the DC side of the second converter CO2 and a voltage stabilizing capacitor is connected in parallel; the first end of the DC-DC converter is connected in parallel to both sides of the voltage stabilizing capacitor; and the second end of the DC-DC converter is connected to the DC traction network OCS3 and the DC rail R.

[0047] The first converter and the second converter can be of various types, such as a full-bridge converter circuit composed of four switching diodes, etc. The embodiments of the present invention are not limited here.

[0048] Among them, the partition or three-port power converter can be regarded as a power converter, while the measurement and control system can include: first voltage transformer PT1, second voltage transformer PT2, first current transformer CT1, second current transformer CT2, voltage transmitter VD, shunt RW and controller (in Figure 2 (Not shown in the diagram); voltage transformer PT1 is connected to the first traction network OCS1 and AC rail R, and second voltage transformer PT2 is connected to the second traction network OCS2 and AC rail R; first current transformer CT1 is connected in series to the feeder of the first AC traction substation ACTS1, and second current transformer CT2 is connected in series to the feeder of the second AC traction substation ACTS2; voltage transmitter VD is connected to the DC traction network OCS3 and DC rail R, and shunt RW is connected in series to the connection line between the DC-DC converter and the DC traction network OCS3; the signal input terminal of the controller is connected to the measurement signal output terminals of the first voltage transformer PT1, the second voltage transformer PT2, the first current transformer CT1, the second current transformer CT2, the voltage transmitter VD, and the shunt RW, respectively, and the signal output terminal of the controller is connected to the control terminal of the three-port power converter TPPC.

[0049] Specifically, the first AC traction substation ACTS1 and the second AC traction substation ACTS2 can be of various types, such as using a three-phase to two-phase transformer as the traction transformer; the DC traction substation DCTS can be of various types, such as using uncontrolled rectification technology to supply power to DC loads, etc. The embodiments of the present invention are not limited here.

[0050] Specifically, in conjunction with the control method in this embodiment of the invention, the three-port power converter TPPC can preferentially compensate the DC traction network voltage and balance the target transmission power between the first AC traction network OSC1 and the second AC traction network OSC2. Additionally, it can perform reactive power compensation based on the AC specified voltage range of the AC traction network. If the AC traction network voltage exceeds the upper limit of the specified AC voltage range, the converter absorbs inductive reactive power; if it exceeds the lower limit of the specified AC voltage range, the converter absorbs capacitive reactive power. The measurement and control system MCS acquires the voltage U1 and current I1 of the first AC traction network OSC1, the voltage U2 and current I2 of the second AC traction network OCS2, and the voltage U3 of the DC traction network OCS3; and calculates the load power P of the first AC traction network OCS1. L1 The load power P of the second AC traction network OCS2 L2 Let the active power transmitted by the first converter CO1 be P1, and the reactive power absorbed be Q1; let the active power transmitted by the second converter CO2 be P2, and the reactive power absorbed be Q2; and let the power transmitted by the DC-DC converter be P. dc The equivalent impedance from the AC traction network load to the traction substation is R. ac +jX ac The equivalent impedance from the DC traction network load to the traction substation is R. dc Let U1' and U2' be the voltage values ​​of the AC traction network after the DC traction network voltage and power are balanced (which can be obtained from U...). i '=U i -P i R ac / U i 'Calculations show that, where i=1, 2); according to the principle of traction network voltage loss, when the load is in traction condition, the traction network voltage is lower than the rated value; when the load is in regenerative condition, the traction network voltage is higher than the rated value; and the rated value of the traction network voltage is within the specified voltage range.'

[0051] Where Rac is the resistance component of the AC traction network line (contact wire and feeder line, etc.), corresponding to the active power loss in the power transmission process; j is the mathematical identifier used in AC circuits to distinguish between "resistance (real part)" and "reactance (imaginary part)," representing the phase characteristics of reactance; Xac is the reactance component of the AC traction network line (generated by line inductance, distributed capacitance, etc.), corresponding to the reactive power characteristics in the power transmission process.

[0052] Of course, the number of AC traction networks in the track interconnection system can be set flexibly and independently, and it is sufficient to have more than zero. This embodiment of the invention does not limit this.

[0053] Specifically, the DC specified voltage range can be set to... The specified voltage range for AC is The rectified power of the first converter CO1 and the second converter CO2 are defined as positive, and the inverter power as negative. The first converter CO1 and the second converter CO2 absorb capacitive reactive power as positive and absorb inductive reactive power as negative. The power flowing into the DC traction substation DCTS from the DC-DC converter is defined as positive, and vice versa. The power is defined as positive when the load is in traction mode and negative when the load is in regenerative mode. The traction load power of the AC traction network is collected and calculated by the measurement and control system MCS, and the three-port power converter TPPC (power converter) is controlled according to the collected traction network voltage.

[0054] Specifically, for a better explanation of the embodiments of the present invention, please refer to... Figure 3 , Figure 3 A flowchart illustrating another control method for a track interconnection system provided by the present invention is shown, used to identify the following eight operating conditions. The specific steps are as follows: (1) If ; 1.1) When When the AC system absorbs regenerative braking power from the DC system, it is determined to be operating condition 1. The active power distribution of the three-port power converter (TPPC) is as follows: ; like ,but ; like ,but ;in i =1, 2.

[0055] 1.2) When and When the AC system absorbs regenerative braking power from the DC system, it is determined to be operating condition 2. The active power distribution of the three-port power converter TPPC is as follows: ; like ,but ; like ,but ;in i =1, 2.

[0056] 1.3) When and When the AC system absorbs power from the DC system, it is determined to be operating condition 3. The active power distribution of the three-port power converter (TPPC) is as follows: ; like ,but ; like ,but ;in i =1, 2.

[0057] (2) If ; 2.1) When At this time, the DC system absorbs the regenerative braking power of the AC system, which is determined to be operating condition 4. The active power distribution of the three-port power converter TPPC is as follows: ; like ,but ; like ,but ;in i =1, 2.

[0058] 2.2) When When the AC system absorbs power from the DC system, it is determined to be operating condition 5. The active power distribution of the three-port power converter (TPPC) is as follows: ; like ,but ; like ,but ;in i =1, 2.

[0059] (3) If ; 3.1) When and When the DC system absorbs the regenerative braking power from the AC system, it is determined to be operating condition 6. The active power distribution of the three-port power converter TPPC is as follows: ; like ,but ; like ,but ;in i =1, 2.

[0060] 3.2) When and When the DC system absorbs power from the AC system, it is determined to be operating condition 7. The active power distribution of the three-port power converter (TPPC) is as follows: ; like ,but ; like ,but ;in i =1, 2.

[0061] 3.3) When The DC system absorbs power from the AC system, which is determined to be operating condition 8. The active power distribution of the three-port power converter (TPPC) is as follows: ; like ,but ; like ,but ;in i =1, 2.

[0062] For a description of the track interconnection system provided in the embodiments of the present invention, please refer to the aforementioned embodiments of the control method for the track interconnection system. The embodiments of the present invention will not be repeated here.

[0063] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the structure of a control device for a track interconnection system provided by the present invention. The control device for the track interconnection system includes: Memory 41 is used to store computer programs; The processor 42 is used to execute computer programs to implement the steps of the control method for the track interconnection system as described in the foregoing embodiments.

[0064] For a description of the control equipment for the track interconnection system provided in this embodiment of the invention, please refer to the aforementioned embodiment of the control method for the track interconnection system. This embodiment of the invention will not be repeated here.

[0065] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. It should also be noted that in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for a track interconnection system, characterized in that, A controller applied to a track interconnection system, wherein the power converter in the track interconnection system is connected to both the AC traction network and the DC traction network to realize AC-DC power conversion, including: If the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the amount by which the DC traction network voltage value exceeds the specified DC voltage range and the load conditions of the AC traction network, so that the voltage value of the DC traction network returns to the specified DC voltage range; the load conditions include traction conditions and regenerative conditions. If the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the adjustable range of the DC traction network voltage value within the specified DC voltage range and the load conditions of the AC traction network, so as to absorb or compensate the AC traction network for electrical energy. The power converter in the control track interconnection system performs power migration according to the target transmission power.

2. The control method for the track interconnection system according to claim 1, characterized in that, If the voltage value of the DC traction network exceeds the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the amount by which the DC traction network voltage exceeds the specified DC voltage range and the load conditions of the AC traction network. If the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is regenerative, the first transmission power is taken as the target transmission power; the first transmission power is: the transmission power determined by taking the voltage value of the DC traction network returning to the upper limit of the DC specified voltage range as the target. If the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is the traction condition, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network; the second transmission power is the transmission power determined with the voltage value of the DC traction network returning to the lower limit of the DC specified voltage range as the target. If the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is regenerative, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network. If the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is the traction condition, the second transmission power will be used as the target transmission power.

3. The control method for the track interconnection system according to claim 2, characterized in that, If the voltage value of the DC traction network is greater than the upper limit of the specified DC voltage range, and the load condition of the AC traction network is the traction condition, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network, including: If the voltage value of the DC traction network is greater than the upper limit of the DC specified voltage range, and the load condition of the AC traction network is the traction condition, determine whether the first transmission power can meet the load power of the AC traction network. If possible, the first transmission power shall be used as the target transmission power; If not, the lower of the absolute values ​​of the second transmission power and the load power of the AC traction network shall be used as the target transmission power.

4. The control method for the track interconnection system according to claim 2, characterized in that, If the voltage value of the DC traction network is less than the lower limit of the specified DC voltage range, and the load condition of the AC traction network is regenerative, the target transmission power is determined based on the first transmission power, the second transmission power, and the load power of the AC traction network, including: If the voltage value of the DC traction network is less than the lower limit of the DC specified voltage range, and the load condition of the AC traction network is regenerative, determine whether the load power of the AC traction network can meet the second transmission power. If possible, the lower of the first transmission power and the load power of the AC traction network shall be used as the target transmission power. If not, then the second transmission power will be used as the target transmission power.

5. The control method for the track interconnection system according to claim 2, characterized in that, The process of determining the first transmission power includes: The first transmission power is determined by the first relational expression; The process of determining the second transmission power includes: The second transmission power is determined by the second relational expression; The first relation includes: ； The second relation includes: ； in, This is the upper limit of the specified DC voltage range. This is the lower limit of the specified DC voltage range. U 3 represents the voltage value of the DC traction network. R dc This is the equivalent impedance from the DC traction network load to the traction substation.

6. The control method for the track interconnection system according to claim 1, characterized in that, If the voltage value of the DC traction network does not exceed the specified DC voltage range, the target transmission power between the AC traction network and the DC traction network is determined based on the adjustable range of the DC traction network voltage value within the specified DC voltage range and the load conditions of the AC traction network, including: If the voltage value of the DC traction network does not exceed the specified DC voltage range, and the load condition of the AC traction network is regenerative, the lower of the absolute values ​​of the first transmission power and the load power of the AC traction network shall be used as the target transmission power. If the voltage value of the DC traction network does not exceed the specified DC voltage range, and the load condition of the AC traction network is the traction condition, the lower of the absolute values ​​of the second transmission power and the load power of the AC traction network shall be taken as the target transmission power.

7. The control method for a track interconnection system according to any one of claims 1 to 6, characterized in that, After the power converter in the control track interconnection system performs power migration according to the target transmission power, the control method of the track interconnection system further includes: Determine whether the voltage value of the AC traction network exceeds the specified AC voltage range; If it exceeds the limit, the target reactive power of the AC traction network shall be determined based on the amount by which the voltage value of the AC traction network exceeds the specified AC voltage range. The power converter in the control track interconnection system performs reactive power compensation on the AC traction network according to the target reactive power.

8. A track line interconnection system, characterized in that, include: Power converters that are connected to AC traction networks and DC traction networks respectively; The detection module is used to detect the electrical energy parameters of the DC traction network and the AC traction network; A controller for implementing the steps of the control method for the track interconnection system as described in any one of claims 1 to 6.

9. The track interconnection system according to claim 8, characterized in that, The power converter includes: The first sub-power converter is connected to the first AC traction network on its AC side and is used to perform power conversion between the first AC traction network and the DC transformer. The second sub-power converter is connected to the second AC traction network on its AC side and is used to perform power conversion between the second AC traction network and the DC transformer. The DC transformer has its first end connected to the DC side of the first sub-power converter and the DC side of the second sub-power converter, and its second end connected to the DC traction network for DC voltage regulation.

10. A control device for a track interconnection system, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the control method for the track interconnection system as described in any one of claims 1 to 7.

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