Electrified railway power regulation and control and braking energy recovery device based on switch multiplexing

Abstract

The utility model discloses an electrified railway power regulation and control and braking energy recovery device based on switch multiplexing, which comprises a traction transformer, the primary side of the traction transformer is connected with a three-phase high-voltage power grid, and the secondary side of the traction transformer is connected with a traction feeder line. The head end of the traction feeder line is connected with the primary side of the coupling transformer, the coupling transformer is provided with a plurality of sets of secondary side windings, and each set of winding is connected with one set of energy storage embedded back-to-back converter module based on switch multiplexing. In the converter module, a pair of H-bridge converters form a back-to-back structure through an intermediate direct-current link, an energy storage battery is embedded into bridge arms of the H-bridge converters, each bridge arm is formed by connecting four electronic power switches in series, the head end of the secondary side of a coupling transformer is connected with the midpoint of one bridge arm of the H-bridge converter through an inductor, and the head end of the secondary side of the coupling transformer is connected with the midpoint of the other bridge arm of the H-bridge converter. And the tail end of the secondary side is connected with the midpoint of the other bridge arm. According to the utility model, through the energy storage embedded back-to-back converter based on switch multiplexing, power regulation and control between two traction feeder lines and recovery of regenerative braking energy can be realized.

Description

Technical Field

[0001] The present invention relates to the field of traction power supply for electrified railways, and particularly to a device for power regulation and braking energy recovery of electrified railways based on switch multiplexing. Background Art

[0002] In recent years, the electrified railways in China have developed rapidly, and the railway mileage has increased significantly. In particular, the mileage of high-speed railways has become the top in the world. However, with the rapid expansion of the electrified railway mileage, the power supply and operation costs have also increased day by day. Facing this challenge, the railway department urgently needs to solve the problem of effectively improving the comprehensive utilization efficiency of electric energy, so as to achieve the goals of energy conservation, emission reduction and operation cost reduction.

[0003] Although the regenerative braking energy generated by electrified railways is abundant, its current utilization is not sufficient. How to effectively utilize this part of energy and improve its utilization rate is an important problem to be solved. At present, the utilization methods of regenerative braking energy of electrified railways mainly include energy consumption type, energy feedback type and energy storage type. However, the energy consumption type has poor applicability and flexibility. The energy feedback type directly feeds a large amount of regenerative braking energy back to the power grid, which will cause a greater impact on the power grid. The energy storage type can improve the comprehensive utilization efficiency of energy, improve the system flexibility and maintain the stability of the power grid voltage. In addition, to achieve the efficient utilization of regenerative braking energy of electrified railways, a reasonable energy management and control strategy needs to be designed to ensure the stable and efficient utilization of regenerative braking energy. Summary of the Invention

[0004] The purpose of the present utility model is to effectively utilize the regenerative braking energy, improve the comprehensive utilization efficiency of energy, improve the system flexibility and maintain the stability of the power grid voltage. The present utility model does not require an additional DC / DC converter. By directly embedding the energy storage battery into the H-bridge back-to-back converter module, the system structure is more compact. Through switch multiplexing, power regulation and braking energy recovery can be conveniently realized. The present utility model can flexibly determine the number of energy storage embedded back-to-back converters based on switch multiplexing according to the system capacity requirements. The control is more flexible and the operation is more efficient.

[0005] The technical solution of the present utility model is a device for power regulation and braking energy recovery of electrified railways based on switch multiplexing, which is characterized in that it includes a three-phase high-voltage power grid, a traction transformer, a coupling transformer, an energy storage battery, and an energy storage embedded back-to-back converter module based on switch multiplexing.

[0006] In the device for power regulation and braking energy recovery of electrified railways based on switch multiplexing, the primary side of the traction transformer is connected to the three-phase high-voltage power grid, and the secondary side is connected to the α and β phase traction feeders. The heads of the α and β phase traction feeders are connected to the primary sides of the coupling transformers CT α 、CT β primary sides, and the coupling transformer CTα , CT β Both are provided with multiple secondary windings, and each set of windings is respectively connected to a set of energy storage embedded back-to-back converter modules based on switch multiplexing.

[0007] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, the energy storage embedded back-to-back converter module based on switch multiplexing includes a pair of single-phase H-bridge converters and an intermediate DC link formed by the first capacitor C dc0 A pair of single-phase H-bridge converters form a back-to-back structure through the intermediate DC link. The single-phase H-bridge converter is composed of two four-switch bridge arms, and the four-switch bridge arms are formed by four power electronic switches connected in series. The connection points are U, M, and D points respectively. The energy storage battery is embedded in the four-switch bridge arms in parallel through the U and D points.

[0008] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, the first ends of the multiple secondary windings of the coupling transformer are connected to the midpoint of one bridge arm of the H-bridge converter through an inductor, and the second ends are connected to the midpoint of the other bridge arm.

[0009] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, among the four four-switch bridge arms in a pair of H-bridge converters, a total of sixteen power electronic switches are all connected in parallel with reverse freewheeling diodes.

[0010] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, the traction transformer adopted is a three-phase V / v traction transformer.

[0011] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, the energy storage embedded back-to-back converter based on switch multiplexing can flexibly determine the converter multiplicity according to the system capacity requirements. The utility model can conveniently realize the power regulation between two traction feeders and the recovery of regenerative braking energy by multiplexing switches.

[0012] The described electrified railway power regulation and braking energy recovery device based on switch multiplexing has three working modes. Working mode 1 is the power transfer between the α and β phase traction feeders, working mode 2 is the power interaction between the energy storage battery on the β side and the α phase traction feeder, and working mode 3 is the power interaction between the energy storage battery on the α side and the β phase traction feeder.

[0013] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, in working mode 1, there is no power interaction between the energy storage and the traction power supply system, and the power regulation between the α and β phase traction feeders is realized.

[0014] For the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, in working mode 2, power interaction occurs between the energy storage battery on the β side and the traction feeder of the α phase. When the traction feeder of the α phase is in the regenerative braking state, the recovered braking energy charges the energy storage battery on the β side. When the traction feeder of the α phase is in the traction state and the energy storage battery has sufficient power, the energy storage battery on the β side delivers traction power to the traction feeder of the α phase.

[0015] For the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, in working mode 3, power interaction occurs between the energy storage battery on the α side and the traction feeder of the β phase. When the traction feeder of the β phase is in the regenerative braking state, the recovered braking energy charges the energy storage battery on the α side. When the traction feeder of the β phase is in the traction state and the energy storage battery has sufficient power, the energy storage battery on the α side delivers traction power to the traction feeder of the β phase.

[0016] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, the present utility model realizes power regulation between two traction feeders through an H-bridge back-to-back converter structure. By directly embedding the energy storage battery into the four-switch bridge arm and multiplexing the switches of the switch bridge arm, controlling the unilateral DC / DC bidirectional converter and the unilateral H-bridge converter can conveniently realize power interaction between the energy storage battery on the α side and the traction feeder of the β phase, and between the energy storage battery on the β side and the traction feeder of the α phase, and realize the recovery of regenerative braking energy under the traction state of the locomotive group. Description of the Drawings

[0017] By referring to the attached drawings, the features and advantages of the present utility model can be more clearly understood. The attached drawings should not be construed as any limitation to the present utility model.

[0018] Figure 1 : General structure block diagram of the present utility model.

[0019] Figure 2 : Four-switch bridge arm block diagram defining the switch group.

[0020] Figure 3 : Circuit diagram of working mode 1 (taking #0 as an example).

[0021] Figure 4 : Simplified circuit diagram of working mode 1.

[0022] Figure 5 : Circuit diagram of working mode 2 (taking #0 as an example).

[0023] Figure 6 : Simplified circuit diagram of boost converter mode in working mode 2.

[0024] Figure 7 : Simplified circuit diagram of buck converter mode in working mode 2.

[0025] Figure 8 : Circuit diagram of working mode 3 (taking #0 as an example).

[0026] Figure 9 : Simplified circuit diagram of the boost conversion mode in working mode 3.

[0027] Figure 10 : Simplified circuit diagram of the buck conversion mode in working mode 3. Specific implementation manners

[0028] For the convenience of those of ordinary skill in the art to understand and implement the present invention, the present utility model invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the description herein is only for the purpose of illustration and explanation of the present invention and is not intended to limit the present invention.

[0029] Figure 1 As shown in the block diagram of an electrified railway power regulation and braking energy recovery device based on switch multiplexing provided by the present utility model, Figure 1 An electrified railway power regulation and braking energy recovery device based on switch multiplexing includes a three-phase high-voltage power grid, a traction transformer, a coupling transformer, an energy storage battery, and a switch-multiplexing-based energy storage embedded back-to-back converter module.

[0030] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, the primary side of the traction transformer is connected to the three-phase high-voltage power grid, and the secondary side is connected to the α and β-phase traction feeders. The heads of the α and β-phase traction feeders are connected to the primary sides of the coupling transformers CT α , CT β . The coupling transformers CT α , CT β are each provided with multiple sets of secondary windings, and each set of windings is respectively connected to a switch-multiplexing-based energy storage embedded back-to-back converter module.

[0031] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, the switch-multiplexing-based energy storage embedded back-to-back converter module includes a pair of single-phase H-bridge converters and an intermediate DC link formed by the first capacitor C dc0 . A pair of single-phase H-bridge converters form a back-to-back structure through the intermediate DC link. The single-phase H-bridge converter is composed of two four-switch bridge arms, and the four-switch bridge arms are formed by four power electronic switches connected in series. The connection points are U, M, and D points respectively. The energy storage battery is embedded in the four-switch bridge arms in parallel through the U and D points.

[0032] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, the heads of multiple sets of secondary windings of the coupling transformer are connected to the midpoint of one bridge arm of the H-bridge circuit through an inductor, and the ends of the secondary sides are connected to the midpoint of the other bridge arm.

[0033] In the described electrified railway power regulation and braking energy recovery device based on switch multiplexing, among the four four-switch bridge arms in a pair of H-bridge converters, a total of sixteen power electronic switches are each connected in parallel with a reverse freewheeling diode.

[0034] Figure 2 As shown in the H-bridge switch group definition diagram, since the present utility model realizes electrified railway power regulation and braking energy recovery through switch multiplexing, for the convenience of explaining and interpreting the present invention, the switches of the four-switch bridge arms are defined. As Figure 2 shown, the two switches on the upper bridge arm are defined as the upper switch group (the upper two switches, UTS), the two switches on the lower bridge arm are defined as the lower switch group (the two switches, LTS), the second and third switches in the bridge arm are defined as the middle switch group (the middle two switches, MTS), and the remaining two switches are defined as the remaining switch group (the rest two switches, RTS).

[0035] The working mode 1 of the described electrified railway power regulation and braking energy recovery device based on switch multiplexing is as shown in Figure 3 At this time, without considering the energy storage battery, the energy storage-embedded back-to-back converter module based on switch multiplexing realizes power transfer between the α and β phase traction feeders through the H-bridge back-to-back converter structure. Since the α and β sides of the back-to-back structure are symmetric and the working principles on both sides are similar, for the convenience of explanation, only the α-side single H-bridge converter is taken as an example to illustrate the specific working mode. Figure 4 As the simplified circuit diagram of working mode 1, working mode 1 only involves the UTS and LTS switch groups. When i αc0 > 0, UTS α02 and LTS α01 remain off. When UTS α01 and LTS α02 conduct simultaneously, v ac0 = U dc0 . The first capacitor C dc0 is charged and the current i αc0 gradually decreases. When UTS α01 and LTS α02 remain off and UTS α02 and LTS α01 conduct simultaneously, v ac0 = -U dc0 . The first capacitor C dc0 discharges and the current i αc0 gradually increases. Similarly, when the current i αc0 < 0, when UTS α01 and LTS α02 conduct simultaneously, v ac0 = Udc0 The first capacitor C dc0 discharges, and the absolute value of the current |i αc0 | gradually increases. UTS α02 and LTS α01 When they are turned on simultaneously, the first capacitor C dc0 is charged, and the absolute value of the current |i αc0 | gradually decreases. This operating mode can achieve power transfer between two feeders.

[0036] The operating mode 2 of the power regulation and braking energy recovery device for electrified railways based on switch multiplexing is as Figure 5 shown. Without considering the β-side winding and the α-side energy storage battery, since the power conversion mode of the H-bridge converter module has been described in operating mode 1, only the DC / DC circuit conversion mode is described in this operating mode. The α-side functions as an H-bridge converter circuit, and only the UTS and LTS switch groups are involved. The β-side energy storage battery forms a bidirectional DC / DC circuit through MTS and RTS. The specific working process is as Figure 6 shown in the simplified circuit diagram of operating mode 2. When RTS β01 , RTS β02 remain off, and MTS β01 , MTS β02 alternately conduct and turn off simultaneously, the bidirectional DC / DC converter circuit is in the boost converter mode at this time. When MTS β01 , MTS β02 conduct, the energy storage batteries B β01 , B β02 respectively form a short-circuit loop through MTS β01 , MTS β02 . At this time, the output current of the energy storage battery gradually increases and the energy is stored in the inductors L β01 , L β02 . The energy is transferred from the energy storage battery to the inductors L β01 , L β02 . When MTS β01 , MTS β02 turn off, the output currents of B β01 , B β02 flow through the freewheeling diodes of RTS β01 , RTS β02 in reverse parallel and flow to the intermediate DC link. The energy is transferred from the energy storage battery and the inductor to the intermediate DC link. When MTS β01 , MTS β02 remain off, and RTS β01 , RTS β02 alternately conduct and turn off simultaneously, the bidirectional DC / DC converter circuit is in the buck converter mode at this time. The specific working process is as Figure 7 shown. When RTS β01 β01, RTS β02 When it is turned on, the intermediate DC link is short-circuited with the energy storage battery. Since the DC bus voltage is greater than the energy storage battery voltage, the output current of the intermediate DC link flows through RTS to the energy storage battery to charge it. At this time, the current gradually increases and the energy is transferred to the inductor and the energy storage battery. When RTS β01 , RTS β02 is turned off, the input current of the energy storage battery flows through MTS β01 , MTS β02 and the freewheeling diodes in antiparallel conduct, and the current will gradually decrease. The energy is transferred from the inductor to the energy storage battery. This working mode realizes the energy interaction between the energy storage battery on the β side and the α-phase traction feeder.

[0037] The working mode 3 of the electrified railway power regulation and braking energy recovery device based on switch multiplexing is as shown in Figure 8 . Without considering the α-side winding and the β-side energy storage battery, since the power conversion mode of the H-bridge converter module has been described in working mode 1, only the DC / DC circuit conversion mode is described in this working mode. The β side is an H-bridge converter circuit, and only the UTS and LTS switch groups are involved. The α-side energy storage battery forms a bidirectional DC / DC circuit through MTS and RTS. The specific working process is as shown in Figure 9 the simplified circuit diagram of working mode 3. When RTS α01 , RTS α02 remain off and MTS α01 , MTS α02 alternately conduct and turn off simultaneously, the bidirectional DC / DC converter circuit is in the boost conversion mode at this time. When MTS α01 , MTS α02 conduct, the energy storage batteries B α01 , B α02 are respectively short-circuited through MTS α01 , MTS α02 to form a short-circuit loop. At this time, the output current of the energy storage battery gradually increases and the energy is stored in the inductors L α01 , L α02 . The energy is transferred from the energy storage battery to the inductors L α01 , L α02 . When MTS α01 , MTS α02 turn off, the output currents of B α01 , B α02 flow through the freewheeling diodes of RTS α01 , RTS α02 in antiparallel and flow to the intermediate DC link. The energy is transferred from the energy storage battery and the inductor to the intermediate DC link. When MTS α01 , MTS α02 remain off and RTS α01 , RTS α02When conducting and turning off alternately at the same time, the bidirectional DC / DC converter circuit is in the buck converter mode at this time. The specific working process is as follows Figure 10 shown. When RTS α01 and RTS α02 are conducting, the intermediate DC link is short-circuited with the energy storage battery. Since the DC bus voltage is greater than the energy storage battery voltage, the output current of the intermediate DC link flows through RTS to the energy storage battery to charge it. At this time, the current gradually increases and the energy is transferred to the inductor and the energy storage battery. When RTS α01 and RTS α02 are turned off, the input current of the energy storage battery continues to flow through the freewheeling diodes of MTS α01 and MTS α02 . The current will gradually decrease, and the energy is transferred from the inductor to the energy storage battery. This working mode realizes the energy interaction between the energy storage battery on the α side and the β-phase traction feeder. This working mode realizes the bidirectional flow of energy between the energy storage battery B β and the α-phase traction feeder.

[0038] It should be understood that the above description is relatively detailed and should not be considered as a limitation on the protection scope of the present invention patent. For those skilled in the art of the present utility model, any modifications, equivalent replacements, improvements, etc., made without departing from the spirit of the present utility model or exceeding the scope defined by the appended claims shall be included within the protection scope of the present utility model.

Claims

1. An electrified railway power control and braking energy recovery device based on switch reuse, characterized in that: It includes three-phase high-voltage power grid, traction transformer, coupling transformer, energy storage battery, and energy storage embedded back-to-back converter module based on switch reuse; The primary side of the traction transformer is connected to the three-phase high-voltage power grid, and the secondary side is connected to the α and β phase traction feeders. The head end of the α and β phase traction feeders is connected to the coupling transformer CT. α , CT β The primary side is connected to the coupling transformer CT α , CT β Multiple sets of secondary windings are provided, and each set of windings is respectively connected to a set of energy storage embedded back-to-back converter modules based on switch reuse.

2. The device for power control and braking energy recovery of electrified railway based on switch reuse according to claim 1 is characterized in that: The switch multiplexing-based energy storage embedded back-to-back converter module includes a pair of single-phase H-bridge converters and a first capacitor C dc0 The intermediate DC link is composed of a pair of single-phase H-bridge converters to form a back-to-back structure through the intermediate DC link. The single-phase H-bridge converter is composed of two four-switch bridge arms. Each four-switch bridge arm is composed of four power electronic switches in series. The connection points are U, M, and D respectively. The energy storage battery is embedded in the four-switch bridge arm in parallel from U and D points.

3. The device for power control and braking energy recovery of electrified railway based on switch reuse according to claim 1, characterized in that: The first ends of the multiple sets of secondary windings of the coupling transformer are connected to the midpoint of one bridge arm of the H-bridge circuit through an inductor, and the secondary end is connected to the midpoint of the other bridge arm.

4. The device for power control and braking energy recovery of electrified railway based on switch reuse according to claim 1, characterized in that: In the four four-switch bridge arms of a pair of H-bridge converters inside the device, a total of sixteen power electronic switches are connected in parallel with reverse freewheeling diodes.

5. The device for power control and braking energy recovery of electrified railway based on switch reuse according to claim 1, characterized in that: The traction transformer is a three-phase V / v traction transformer.

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