Rail transit power supply system, control method and related device

Abstract

The embodiment of the invention provides a rail transit power supply system, a control method and a related device. The rail transit power supply system comprises an alternating-current bus, a direct-current bus, a transformer, a bidirectional converter and a direct-current wire inlet switch. The bidirectional converter comprises a bidirectional converter circuit with a switching tube and a direct current capacitor, and an alternating current side low-voltage switch and a controller which are connected between the transformer and the bidirectional converter circuit; the controller controls to disconnect the AC side low-voltage switch, the switch tube and the DC inlet wire switch under the condition that the AC bus loses voltage, and controls the bidirectional converter to automatically execute the grid connection process under the condition that the voltage recovery of the AC bus is detected. According to the rail transit power supply system, the control method and the related device, the workload of operation and maintenance personnel can be reduced.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of power electronics technology, and specifically to a rail transit power supply system, a control method, and related devices. Background Art

[0002] In recent years, with the rapid development of power electronics technology, bidirectional converters have been widely used in rail transit traction power supply systems. Compared with traditional diode rectifier units, bidirectional converters have many advantages, including the ability to recycle train braking energy, reduce voltage fluctuations in DC traction networks, and improve power quality.

[0003] In the prior art, when the rail transit traction power supply system is inspected or repaired, a switching operation is performed, that is, the rail transit traction power supply system is switched from one AC power source to another AC power source. During the switching process, the bidirectional converter needs to be shut down, and after the switching is completed, the operation and maintenance personnel restart the bidirectional converter, which obviously requires a lot of work for the operation and maintenance personnel. Summary of the invention

[0004] The present application provides a rail transit power supply system, a control method and related devices, which can reduce the manpower required for the rail transit power supply system to a certain extent.

[0005] In the first aspect, an embodiment of the present application provides a rail transit power supply system, comprising: an AC bus and a DC bus; a transformer connected to the AC bus; a bidirectional converter connected between the transformer and the DC bus, a DC incoming line switch being arranged between the bidirectional converter and the DC bus; the bidirectional converter comprises a bidirectional conversion circuit having a switch tube and a DC capacitor, and an AC side low-voltage switch and a controller connected between the transformer and the bidirectional conversion circuit; the controller is used to control the disconnection of the AC side low-voltage switch, the switch tube and the DC incoming line switch when the AC bus loses voltage, and to control the bidirectional converter to automatically execute the grid-connected process when the voltage of the AC bus is detected to be restored.

[0006] Optionally, when the AC bus loses voltage, the controller controls the shutdown of the low-voltage side switch, the switch tube and the DC incoming switch, including: first stopping sending a drive signal to the switch tube of the bidirectional conversion circuit, disconnecting the AC side low-voltage switch, and disconnecting the DC incoming switch.

[0007] Optionally, the bidirectional converter also includes a soft-start circuit connected between the transformer and the bidirectional conversion circuit; when the voltage of the AC bus is restored, the controller controls the bidirectional converter to automatically execute the grid-connected process, including: the controller first controls the soft-start circuit to be turned on to pre-charge the DC capacitor included in the bidirectional conversion circuit, and then controls the soft-start circuit to be turned off and controls the AC side low-voltage switch to be closed, and sends a drive signal to the switch tube of the bidirectional conversion circuit; when the DC side output voltage of the bidirectional conversion circuit is not less than the specified DC voltage, controls the DC incoming line switch to be closed.

[0008] Optionally, the controller is also used to start the timing when the AC side low-voltage switch, the switch tube and the DC incoming switch are disconnected, and control the bidirectional converter to automatically execute the grid-connected process only when the timing duration when the voltage of the AC bus is restored is no more than a specified duration threshold.

[0009] In the second aspect, an embodiment of the present application provides a control method for a rail transit power supply system, including: in the event of an AC bus voltage loss, controlling the disconnection of the AC side low-voltage switch and switch tube of the bidirectional converter, and controlling the disconnection of the DC incoming switch between the bidirectional converter and the DC bus; when it is detected that the voltage of the AC bus has recovered, controlling the bidirectional converter to automatically execute the grid-connected process.

[0010] Optionally, the situation of the AC bus losing voltage includes: determining that the AC bus losing voltage is based on an AC bus voltage signal received and fed back by a first voltage detection module connected to the AC bus; or determining that the AC bus losing voltage is based on a transformer voltage signal received and fed back by a second voltage detection module connected to the low-voltage side of the transformer.

[0011] Optionally, in the event of an AC bus voltage loss, the step of controlling the disconnection of the switching element of the bidirectional converter includes: stopping sending a drive signal to the switch tube of the bidirectional converter, disconnecting the AC side low-voltage switch between the bidirectional converter and the AC power grid, and disconnecting the DC input switch of the bidirectional converter.

[0012] Optionally, a slow-start circuit is arranged between the bidirectional converter and the AC power grid; when the voltage of the AC bus is restored, the step of controlling the bidirectional converter to automatically execute the grid-connected process includes: controlling the slow-start circuit to be turned on to pre-charge the DC capacitor included in the bidirectional converter; controlling the slow-start circuit to be turned off, and controlling the AC side low-voltage switch to be closed, and sending a driving signal to the switch tube; when the DC side output voltage of the bidirectional converter is not less than the specified DC voltage, controlling the DC incoming line switch to be closed.

[0013] Optionally, the method also includes: starting timing when the switching element of the bidirectional converter is disconnected; when the voltage of the AC bus is restored, controlling the bidirectional converter to automatically execute the grid-connected process, including: controlling the bidirectional converter to automatically execute the grid-connected process only when the timing duration when the voltage of the AC bus is restored is not greater than a specified duration threshold.

[0014] In a third aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the control method of the rail transit power supply system as described above is implemented.

[0015] In a fourth aspect, an embodiment of the present application provides a computer program product, which, when executed by a processor, implements the control method of the rail transit power supply system as described above.

[0016] In multiple implementations provided in the present application, when AC bus voltage loss is detected, the controller immediately disconnects the switching elements of the bidirectional converter, and automatically executes the grid-connected process when the AC bus voltage is restored. In this way, there is no need to manually restart the bidirectional converter as required in related technologies, thereby reducing the workload of operation and maintenance personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 A topological diagram of a rail transit power supply system provided for one embodiment of the present specification.

[0019] Figure 2 A topological diagram of a rail transit power supply system is provided for one embodiment of the present specification, wherein the internal topological structure of a substation is detailed.

[0020] Figure 3 A module schematic diagram of a rail transit power supply system provided for one embodiment of the present specification.

[0021] Figure 4 A module schematic diagram of a rail transit power supply system provided for one embodiment of the present specification. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0023] In the description of the embodiments of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0024] See also Figure 1 and Figure 2 . The rail transit power supply system 100 may include an AC power grid 110, a DC contact network 112 and a plurality of substations 114. The rail transit power supply system 100 uses the electric energy in the AC power grid 110 to supply power to the DC contact network 112. Specifically, the substation 114 includes an AC bus 126, a DC bus 205 and a bidirectional converter 115, etc. The AC bus 126 may include a first bus section 128 and a second bus section 130 connected by a bus tie switch 300, wherein the first bus section 128 is connected to the AC power grid 110 through a first bus incoming line 125, wherein the first bus incoming line 125 is provided with a bus incoming line switch 301. The second bus section 130 is connected to the AC power grid 110 through a second bus incoming line 127, wherein the second bus incoming line 127 is provided with a bus incoming line switch 302. The AC side of the bidirectional converter 115 can be connected to the first bus 128 through the transformer 124, and the DC side of the bidirectional converter 115 is connected to the DC bus 205 through the DC feeder switch 203. A DC feeder switch 207 is provided between the DC bus 205 and the DC contact network 112.

[0025] In some cases, a switching operation is required for the purpose of inspection and maintenance. For example, the first bus incoming line 125 that supplies power to the AC bus 126 is changed to the second bus incoming line 127. During the switching process, it is necessary to first disconnect the bus incoming line switch 301, and through the standby automatic switching action of the bus tie switch 300, the bus tie switch 300 is automatically closed and switched to the bus incoming line switch 302 for power supply. In this way, during the switching process, the bidirectional converter 115 will have a short-term AC bus voltage loss. That is, the transformer 124 connected to the bidirectional converter 115 loses voltage input. At this time, it is necessary to disconnect the switch elements on the AC side and the switch elements on the DC side of the bidirectional converter 115. Otherwise, after the switching operation is completed, when the voltage of the first section of the AC bus 128 is restored, the switch tube and DC capacitor of the bidirectional converter 115 will be subjected to a large impact, especially the switch tube included in the bidirectional converter 115, which is easily damaged by a large current impact. For example, the switch tube of the bidirectional converter 115 may be an IGBT (Insulated Gate Bipolar Transistor). In the related art, after the bidirectional converter 115 disconnects the switch element on the AC side and the switch element on the DC side, as the operation and maintenance personnel complete the switching operation, the operation and maintenance personnel are required to manually start the bidirectional converter 115 to complete the grid connection process of the bidirectional converter 115. Obviously, this will require the operation and maintenance personnel to invest more manual workload.

[0026] Please also read Figure 1 , Figure 2 and Figure 3 . An embodiment of the present application provides a rail transit power supply system 100. The rail transit power supply system 100 includes: an AC bus 126 and a DC bus 205; a transformer 124 connected to the AC bus 126; and a bidirectional converter 115 connected between the transformer 124 and the DC bus 205. A DC incoming line switch 203 is provided between the bidirectional converter 115 and the DC bus 205. The bidirectional converter 115 includes a bidirectional converter circuit 120 having a switch tube S and a DC capacitor C, and AC side low-voltage switches QF1 and QF2 and a controller 129 connected between the transformer 124 and the bidirectional converter circuit 120. The controller 129 is used to control the disconnection of the AC side low-voltage switches QF1 and QF2, the switch tube S and the DC incoming line switch 203 when the AC bus 126 loses voltage, and to control the bidirectional converter 115 to automatically execute the grid connection process when the voltage of the AC bus 126 is detected to be restored.

[0027] In this embodiment, the bidirectional converter 115 has the ability of bidirectional energy transmission, and can convert the electric energy of the AC power grid 110 into the DC power required by the DC contact network 112. It can also feed back excess DC power to the AC power grid 110 when the tram brakes, thereby improving energy utilization efficiency.

[0028] In this embodiment, the switch tube S can, under the action of the driving signal sent by the controller 129, enable the bidirectional converter 115 to convert the electric energy of the AC power grid 110 into DC electric energy, and output it from the DC side to the DC contact network 112, or convert the DC electric energy of the DC contact network 112 into AC electric energy and provide it to the AC power grid 110 through the transformer 124 from the AC side of the bidirectional converter. The AC side low-voltage switches QF1 and QF2 are used to connect or disconnect the bidirectional converter circuit 120 from the transformer 124, and the DC line switch 203 is used to connect or disconnect the bidirectional converter 115 from the DC bus 205. Specifically, the DC line switch 203 is connected to the DC bus 205. When the DC line switch 203 is closed, the DC side of the bidirectional converter circuit 120 is connected to the DC bus 205, and when the DC line switch 203 is disconnected, the DC side of the bidirectional converter circuit 120 is disconnected from the DC bus 205. When the DC feeder switch 207 is closed, the DC bus 205 is connected to the DC contact network 112. When the DC feeder switch 207 is opened, the DC bus 205 is disconnected from the DC contact network 112.

[0029] like Figure 3 As shown. In some embodiments, the rail transit power supply system 100 may further include a first voltage detection module 121 for detecting the voltage of the AC bus 126. The first voltage detection module 121 can detect the voltage of the AC bus 126 and feed back an AC bus voltage signal representing the voltage of the AC bus 126 to the controller 129. The controller 129 can determine whether the connected AC bus 126 has lost voltage based on the received AC bus electrical signal. Specifically, the first voltage detection module 121 can be connected to the first section of the AC bus 128 and continuously detect the voltage of the first section of the AC bus 128.

[0030] like Figure 4 As shown. In some embodiments, the rail transit power supply system 100 may also include a second voltage detection module 122 for detecting the voltage on the low-voltage side of the transformer 124. The second voltage detection module 122 can detect the voltage on the low-voltage side of the transformer 124, and feed back a transformer voltage signal representing the voltage on the low-voltage side of the transformer 124 to the controller 129. The controller 129 can determine whether the AC bus 126 connected to the transformer 124 has lost voltage based on the received transformer voltage signal. Specifically, the second voltage detection module 122 can continuously detect the transformer voltage signal on the low-voltage side of the transformer 124. When the transformer voltage signal indicates that the low-voltage side of the transformer 124 has lost voltage, it can be indirectly considered that the first-end AC bus 128 connected to the transformer 124 has lost voltage.

[0031] In this embodiment, when it is detected that the AC bus 126 loses pressure, the controller 129 controls the disconnection of the AC side low-voltage switches QF1 and QF2, the switch tube S and the DC incoming line switch 203. Specifically, the controller 129 can issue disconnection instructions to the AC side low-voltage switches QF1 and QF2 respectively, stop sending drive signals to the switch tube S, and issue a disconnection instruction to the DC incoming line switch 203. The order in which the AC side low-voltage switches QF1 and QF2, the switch tube S and the DC incoming line switch 203 are disconnected can be in any order, or they can be disconnected at the same time. In some embodiments, the controller 129 can also send an instruction to the dispatching program control of the rail transit power supply system 100 to allow the DC incoming line switch 203 to be disconnected, thereby indirectly controlling the DC incoming line switch 203 to be disconnected.

[0032] In some embodiments, the controller 129 first stops sending a driving signal to the switch tube S, thereby turning off the switch tube S and preventing the current from continuing to flow. At the same time, the controller 129 disconnects the AC side low-voltage switches QF1 and QF2 to cut off the connection between the bidirectional converter circuit 120 and the AC power grid 110 to prevent transient current shocks from being generated when the voltage of the first section of the AC bus 128 is restored. In addition, the controller 129 also disconnects the DC input switch 203 to cut off the connection with the DC bus 205. In this way, the bidirectional converter circuit 120 is isolated, which can avoid shocks to the switch tube S and DC capacitor C in the bidirectional converter circuit 120 when the voltage of the first section of the AC bus 128 is restored, thereby reducing the risk of equipment damage.

[0033] In this embodiment, after the voltage of the first section of the AC bus 128 is restored, the controller 129 can control the bidirectional converter 115 to automatically execute the grid-connected process. The grid-connected process may refer to a control process in which the bidirectional converter stops using the AC power of the AC power grid 110 to convert into DC power to provide power to the DC contact network 112, then reconnects to the AC power grid 110 and the DC contact network 112, and resumes using the AC power of the AC power grid 110 to convert into DC power to provide power to the DC contact network 112. By automatically executing the above control process, the rail transit power supply system 100 can quickly restore the power supply function of the bidirectional converter 115 after the switching operation, without the need for manual intervention. This not only reduces the workload of the operation and maintenance personnel, but also improves the operating efficiency of the rail transit power supply system 100.

[0034] In some embodiments, the first voltage detection module 121 may continuously detect the voltage of the first AC bus 128, and may continuously feed back an AC bus voltage signal indicating the voltage of the first AC bus 128 to the controller 129. The controller 129 determines whether the voltage of the first AC bus 128 is restored according to the received AC bus voltage signal, and controls the bidirectional converter 115 to automatically execute the grid connection process after determining that the voltage of the first AC bus 128 is restored according to the AC bus voltage signal.

[0035] In some embodiments, the second voltage detection module 121 can continuously detect the voltage on the low-voltage side of the transformer 124, and can continuously feed back to the controller 129 a transformer voltage signal indicating the voltage on the low-voltage side of the transformer 124. The controller 129 determines whether the voltage of the first section of the AC bus 128 connected to the transformer 124 has recovered based on the received transformer voltage signal, and controls the bidirectional converter 115 to automatically execute the grid-connection process after determining that the voltage of the first section of the AC bus 128 has recovered based on the transformer voltage signal.

[0036] In some embodiments, a slow-start circuit is provided between the bidirectional conversion circuit 120 and the AC power grid 110; when the voltage of the AC bus 126 is restored, the controller 129 controls the bidirectional converter 115 to automatically execute the grid-connected process, including: the controller 129 first controls the slow-start circuit to be turned on to pre-charge the DC capacitor C included in the bidirectional conversion circuit 120, and then controls the slow-start circuit to be turned off and controls the AC side low-voltage switches QF1 and QF2 to be closed, and sends a driving signal to the switch tube S of the bidirectional conversion circuit 120; when the DC side output voltage of the bidirectional conversion circuit 120 is not less than the specified DC voltage, the DC incoming line switch 203 is controlled to be closed.

[0037] In this embodiment, the slow-start circuit is used to limit the instantaneous inrush current when the bidirectional current conversion circuit 120 is turned on, thereby protecting the DC capacitor C and other devices in the circuit and preventing damage caused by current impact. The slow-start circuit may include a switch KM1 and a resistor R1 connected in series, and KM2 and R2 connected in series. Specifically, when the voltage of the first section of the AC bus 128 is restored, the controller 129 first controls the closure of KM1 and KM2 to allow the DC capacitor C of the bidirectional current conversion circuit 120 to be pre-charged. In this process, the slow-start circuit charges the DC capacitor C with current limiting through the resistors R1 and R2 that can limit current, so that the voltage of the DC capacitor C gradually rises, avoiding instantaneous large current impact on the DC capacitor C and other sensitive components. After the pre-charging of the DC capacitor C is completed, the controller 129 controls the switches KM1 and KM2 to be disconnected. In this embodiment, by setting the slow-start circuit, the bidirectional current conversion circuit 120 weakens the possible large current impact during the grid connection process.

[0038] In this embodiment, after the switches KM1 and KM2 are disconnected, the controller 129 may first control the AC side low-voltage switches QF1 and QF2 to be closed. By closing the AC side low-voltage switches QF1 and QF2, the AC side of the bidirectional converter circuit 120 is reconnected to the AC power grid 110, and the AC voltage begins to be established. After the AC side low-voltage switches QF1 and QF2 are closed, the controller 129 sends a drive signal to the switch tube S of the bidirectional converter circuit 120. Under the control of the drive signal, the switch tube S causes the bidirectional converter circuit 120 to start performing energy conversion, and the DC side output voltage of the bidirectional converter circuit 120 gradually rises.

[0039] In this embodiment, the DC side output voltage of the bidirectional conversion circuit 120 may be the voltage applied by the bidirectional conversion circuit 120 to the DC feeder switch 203. The specified DC voltage is a preset voltage threshold, indicating that the DC side output voltage of the bidirectional conversion circuit 120 reaches a voltage suitable for connection with the DC contact network 112. Specifically, the controller 129 may detect the DC side output voltage of the bidirectional conversion circuit 120. When it is detected that the DC side output voltage is not less than the specified DC bus voltage, the controller 129 may control the DC feeder switch 203 between the bidirectional conversion circuit 120 and the DC bus 205 to close, and the DC feeder switch 207 is always closed during the switching process, so that the DC side of the bidirectional conversion circuit 120 is connected to the DC contact network 112, and the grid connection process is completed.

[0040] In this embodiment, the operations of closing the AC side low-voltage switches QF1 and QF2, sending a drive signal to the switch tube S, detecting the DC side output voltage of the bidirectional converter circuit 120, and closing the DC incoming line switch 203 when the conditions are met are sequentially performed, so as to restore the AC side power supply first, then start the operation of the switch tube S, so that the DC side output voltage rises steadily before closing the DC incoming line switch 203, ensuring that the rail transit power supply system 100 is gradually restored in a stable state, which is beneficial to the overall stability of the rail transit power supply system 100. Furthermore, before the DC side output voltage reaches the specified DC voltage, the DC incoming line switch 203 is not closed, which can prevent current shocks caused by voltage differences and protect the safety of the DC contact network 112 and the internal switch elements of the bidirectional converter circuit 120.

[0041] In some embodiments, the controller 120 is further configured to start timing when disconnecting the AC side low voltage switches QF1 and QF2, the switch tube S and the DC inlet switch 203, and control the bidirectional converter 115 to automatically execute the grid connection process only when the timing duration when the voltage of the first AC bus 128 is restored is not greater than a specified duration threshold. In some embodiments, the specified duration threshold is not less than the time required for the AC voltage loss to return to normal during the AC grid switching process.

[0042] In this embodiment, when the controller 120 detects that the first section of the AC bus 128 loses voltage and controls the disconnection of the AC side low-voltage switches QF1 and QF2, the switch tube S and the DC incoming line switch 203, the controller 129 will also start the timing function to record the duration from the disconnection of the AC side low-voltage switches QF1 and QF2, the switch tube S and the DC incoming line switch 203. Specifically, the controller 129 stops sending a driving signal to the switch tube S of the bidirectional converter circuit 120, and simultaneously disconnects the AC side low-voltage switches QF1 and QF2 and the DC incoming line switch 203 of the bidirectional converter circuit 120, so that the bidirectional converter circuit 120 is completely disconnected from the AC power grid 110 and the DC contact network 112. At the same time, the timing is started to record the duration after the first section of the AC bus 128 loses voltage. When the voltage of the first section of the AC bus 128 is restored, the controller 129 can determine whether to automatically execute the grid connection process according to the timing result. If the timing duration is not greater than the preset specified duration threshold, the controller 129 will control the grid-connected operation of the bidirectional converter circuit 120 according to a predetermined sequence.

[0043] In this embodiment, the specified duration threshold may refer to a preset maximum time limit, which is used to ensure that the grid-connected operation of the bidirectional converter circuit 120 is automatically restored only when the first AC bus 128 loses pressure for a short period of time, such as when a switching operation occurs. The specified duration threshold may not be less than the time required for the first AC bus 128 to lose pressure and return to normal during the switching process. If the timing duration exceeds the specified duration threshold, it indicates that the voltage of the first AC bus 128 may have experienced a long period of voltage loss. At this time, the controller 129 will not automatically execute the grid-connected process, but requires the operation and maintenance personnel to manually check and confirm the status of the rail transit power supply system 100 before performing the recovery operation. This embodiment can achieve rapid automatic recovery after a short power outage, reducing the workload of the operation and maintenance personnel; at the same time, in the case of a long power outage or failure, it avoids the risks that may be caused by the automatic recovery of the rail transit power supply system 100, thereby improving the safety of the rail transit power supply system 100.

[0044] An embodiment of the present specification also provides a control method for a rail transit power supply system, the control method comprising: in the event of an AC bus voltage loss, controlling the disconnection of the AC side low-voltage switch and the switch tube of the bidirectional converter, and controlling the disconnection of the DC incoming switch between the bidirectional converter and the DC bus; in the event of detecting that the voltage of the AC bus has recovered, controlling the bidirectional converter to automatically execute a grid-connected process.

[0045] The specific functions and effects of each step in the control method of the rail transit power supply system can be explained with reference to the aforementioned embodiments and will not be repeated here.

[0046] In some embodiments, the control method of the rail transit power supply system is applied to a controller. The controller can implement the functions described in the above embodiments by executing the control method of the rail transit power supply system. Specifically, the control method of the rail transit power supply system can refer to the above embodiments and will not be described in detail.

[0047] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the control method of the rail transit power supply system as described in the above embodiment is implemented.

[0048] An embodiment of the present application also provides a computer program product, and when the computer program software is executed by a processor, the control method of the rail transit power supply system as described in the above embodiment is implemented.

[0049] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. can transmit electrical signals or data to each other.

[0050] It should be understood that the specific examples in this document are only intended to help those skilled in the art better understand the embodiments of this specification, rather than to limit the scope of the present invention.

[0051] It can be understood that in the various embodiments in this specification, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0052] It can be understood that the various embodiments described in this specification can be implemented individually or in combination, and the embodiments of this specification are not limited to this.

[0053] It can be understood that the processor of the embodiment of the present application can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method implementation can be completed by the hardware integrated logic circuit or software instructions in the processor. The above processor can be a general processor, a digital signal processor (DigitalSignal Processor, DSP), an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiment of the present application can be implemented or executed. The general processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to perform, or the hardware and software modules in the decoding processor are combined and executed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0054] It is understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (programmable ROM, PROM), an erasable programmable read-only memory (erasable PROM, EPROM), an electrically erasable programmable read-only memory (EEPROM) or a flash memory. The volatile memory may be a random access memory (RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0055] Unless otherwise stated, all technical and scientific terms used in the embodiments of this specification have the same meaning as those generally understood by those skilled in the art of the technical field of this specification. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the scope of this specification. The term "and / or" used in this specification includes any and all combinations of one or more related listed items. The singular forms of "a kind of", "above" and "the" used in the embodiments of this specification and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0056] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this specification.

[0057] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0058] In the several embodiments provided in this specification, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0059] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0060] The above is only a specific embodiment of this specification, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in this specification, which should be included in the protection scope of this specification. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A rail transit power supply system, characterized in that: include: AC bus and DC bus; A transformer connected to the AC bus; A bidirectional converter is connected between the transformer and the DC bus, and a DC incoming line switch is arranged between the bidirectional converter and the DC bus; the bidirectional converter includes a bidirectional conversion circuit having a switch tube and a DC capacitor, and an AC side low-voltage switch and a controller connected between the transformer and the bidirectional conversion circuit; the controller is used to control the disconnection of the AC side low-voltage switch, the switch tube and the DC incoming line switch when the AC bus loses voltage, and control the bidirectional converter to automatically execute the grid-connected process when the voltage of the AC bus is detected to be restored.

2. The rail transit power supply system according to claim 1, characterized in that: When the AC bus loses voltage, the controller controls the low-voltage side switch, the switch tube and the DC incoming line switch to be turned off, including: first stopping sending a drive signal to the switch tube of the bidirectional conversion circuit, disconnecting the AC side low-voltage switch, and disconnecting the DC incoming line switch.

3. The rail transit power supply system according to claim 1, characterized in that: The bidirectional converter also includes a slow-start circuit connected between the transformer and the bidirectional conversion circuit; when the voltage of the AC bus is restored, the controller controls the bidirectional converter to automatically execute the grid-connected process, including: the controller first controls the slow-start circuit to be turned on to pre-charge the DC capacitor included in the bidirectional conversion circuit, then controls the slow-start circuit to be turned off and controls the AC side low-voltage switch to be closed, and sends a driving signal to the switch tube of the bidirectional conversion circuit; when the DC side output voltage of the bidirectional conversion circuit is not less than the specified DC voltage, controls the DC incoming line switch to be closed.

4. The rail transit power supply system according to claim 1, characterized in that: The controller is also used to start timing when the AC side low-voltage switch, the switch tube and the DC incoming line switch are disconnected, and control the bidirectional converter to automatically execute the grid-connected process only when the timing duration when the voltage of the AC bus is restored is not greater than a specified duration threshold.

5. A control method for a rail transit power supply system, characterized in that: include: In the case of AC bus voltage loss, control to disconnect the AC side low-voltage switch and switch tube of the bidirectional converter, and control to disconnect the DC line switch between the bidirectional converter and the DC bus; When it is detected that the voltage of the AC bus is restored, the bidirectional converter is controlled to automatically execute a grid-connected process.

6. The control method according to claim 5, characterized in that: The AC bus voltage loss situation includes: Determining that the AC bus loses voltage according to an AC bus voltage signal fed back by a first voltage detection module connected to the AC bus; or The AC bus is determined to be voltage-lost according to a transformer voltage signal fed back by a second voltage detection module connected to the low-voltage side of the transformer.

7. The control method according to claim 5, characterized in that: In the case of AC bus voltage loss, the step of controlling the switching element of the bidirectional converter to be disconnected comprises: Stop sending a driving signal to the switch tube of the bidirectional converter, disconnect the AC side low-voltage switch between the bidirectional converter and the AC power grid, and disconnect the DC line switch of the bidirectional converter.

8. The control method according to claim 5, characterized in that: A slow-start circuit is provided between the bidirectional converter and the AC power grid; when the voltage of the AC bus is restored, the step of controlling the bidirectional converter to automatically execute the grid-connection process comprises: Controlling the soft-start circuit to be turned on to pre-charge the DC capacitor included in the bidirectional converter; Controlling the disconnection of the soft-start circuit, controlling the closing of the AC-side low-voltage switch, and sending a driving signal to the switch tube; When the DC side output voltage of the bidirectional converter is not less than a specified DC voltage, the DC line switch is controlled to be closed.

9. The control method according to claim 5, characterized in that: The method further comprises: starting a timer when disconnecting a switch element of the bidirectional converter; When the voltage of the AC bus is restored, the step of controlling the bidirectional converter to automatically execute the grid-connected process includes: controlling the bidirectional converter to automatically execute the grid-connected process only when the timing duration when the voltage of the AC bus is restored is not greater than a specified duration threshold.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the control method of the rail transit power supply system as described in any one of claims 5 to 9 is implemented.

11. A computer program product, characterized in that When the computer program product is executed by a processor, the control method of the rail transit power supply system as described in any one of claims 5 to 9 is implemented.

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