CN203352263U - Braking energy recovery-type direct current traction power supply system - Google Patents

Abstract

A braking energy recovery-type direct current traction power supply system is provided. The braking energy recovery-type direct current traction power supply system comprises more than two traction substations; each traction substation is provided with more than one transformer which is connected on an alternating current bus; the output side of each transformer is correspondingly connected with one rectifier; the output sides of all rectifiers are connected on the direct current bus of each traction substation; the positive pole and the negative pole of the direct current bus are correspondingly connected with an overhead line system and a steel rail; the positive pole and the negative pole of an electric locomotive are correspondingly connected with the overhead line system and the steel rail respectively; the overhead line system of each adjacent traction substation is connected with one section post; two ends of each section post are connected with the positive pole of a corresponding direct current bus; direct current buses between two adjacent traction substations are provided with an electric vehicle charge and discharge system; the electric vehicle charge and discharge system is connected with the direct current buses of the two adjacent traction substations; and therefore, a direct current annular micro grid in a power supply zone can be formed. The braking energy recovery-type direct current traction power supply system of the utility model is advantageous in improved reliability.

Description

A braking energy recovery type DC traction power supply system

technical field

The utility model relates to a direct current traction power supply system. In particular, it relates to a braking energy recovery type DC traction power supply system which combines an electric vehicle charging and discharging system mainly for battery swapping with a DC traction power supply system.

Background technique

With the rapid development of economy and urbanization, energy crisis, environmental pollution and traffic congestion have become serious problems facing the world today. Urban electrified transportation vehicles (subways, trams and trolleybuses) and electric vehicles can alleviate the increasingly serious traffic congestion in cities, reduce the consumption of limited fossil fuels, reduce air pollution, and achieve energy saving and emission reduction and sustainable urban development. The main means of transportation for the vigorous development of cities in the future.

The development of electric vehicles requires a corresponding charging system. The commonly used charging modes include conventional charging, fast charging and power battery pack quick replacement system (referred to as battery replacement). For urban public transport electric vehicles, battery swapping is a good charging mode. The electric vehicle charging system not only requires huge construction costs, but also has many adverse effects on the power system. At the same time, the electric vehicle power battery is also a huge capacity energy storage device.

Traditional DC traction power supply systems usually use diode rectifiers for power supply, and there are unilateral and bilateral power supply methods for traction substations to catenary. There are two voltage levels of DC power supply stipulated in my country's national standard: 750V and 1500V. The braking energy of the electric locomotive is usually consumed in the braking resistor, which not only causes a waste of energy, but also increases the temperature of the tunnel, increases the burden on the temperature control system, and further leads to a waste of energy. The recovery and utilization of electric locomotive braking energy is the future development direction of traction power supply system.

As shown in Figure 1, the existing DC traction power supply system includes: one or more than two traction substations 1 for providing DC power to the electric locomotive 2, the traction substation 1 adopts the traditional diode rectification DC traction power supply system . Each traction substation 1 is composed of a transformer 11 , a rectifier 12 , a DC bus 13 , a catenary 14 , a rail 15 and a partition 16 . Wherein, the transformer 11 may be a double-winding transformer, a three-winding transformer, or a three-winding transformer with a phase-shift of ±7.5° whose primary sides are connected in a delta extension. The rectifier 12 may be a six-pulse rectifier, a 12-pulse rectifier or a 24-pulse rectifier.

However, in the existing DC traction power supply system, the power factor of the main substation on the AC side is very low during the trough and outage of the electric locomotive, and reactive power compensation measures are required.

Contents of the invention

The technical problem to be solved by the utility model is to provide a braking energy recovery type DC traction power supply system, which can reduce the fluctuation range of the DC voltage of the existing DC traction power supply system, realize the recovery and utilization of the braking energy of the electric locomotive, and improve the DC traction power supply system. The power factor of the main substation on the AC side of the traction power supply system at low load and no load can improve the reliability of the DC traction power supply system and reduce the construction cost of the electric vehicle charging system; economics of the entire system.

The technical solution adopted by the utility model is: a braking energy recovery type DC traction power supply system, including more than two traction substations for providing DC electric energy to electric locomotives, and each traction substation is provided with more than one traction substation For the transformers connected to the AC bus, the output side of each transformer is connected to a rectifier, and the output sides of all the rectifiers are connected to the DC bus of the traction substation where they are located. The positive and negative poles of the DC bus are respectively connected to the contact grid and rail, the positive and negative poles of the electric locomotive are respectively connected to the catenary and the rail, and each traction substation catenary is connected to a partition station, and the two ends of the partition station are also connected to the corresponding DC bus An electric vehicle charging and discharging system is installed on the DC bus between two adjacent traction substations, and the electric vehicle charging and discharging system is connected to the DC buses of two adjacent traction substations, so that a power supply A DC ring microgrid is formed in the partition.

The electric vehicle charging and discharging system includes an electric vehicle charging and discharging DC bus connected to the DC buses of two adjacent traction substations, and more than one bidirectional DC-DC charging connected to the electric vehicle charging and discharging DC bus. discharge machine.

The output end of each bidirectional DC-DC charging and discharging motor is connected to the power battery of the electric vehicle.

The output end of each bidirectional DC-DC charging and discharging motor connected to the power battery of the electric vehicle is also connected in parallel with a supercapacitor.

A braking energy recovery type DC traction power supply system, including a traction substation for providing DC power to electric locomotives, the traction substation is provided with more than one transformer connected to the AC bus, and the output side of each transformer corresponds to A rectifier is connected, and the output sides of all rectifiers are connected to the DC bus of the traction substation where they are located. The positive and negative poles of the DC bus are respectively connected to the catenary and rails, and the positive and negative poles of the electric locomotive are respectively corresponding to Connecting catenary and steel rails, an electric vehicle charging and discharging system is arranged on the DC bus, and the electric vehicle charging and discharging system is connected with the DC bus of the traction substation, thereby forming a DC ring microgrid in a power supply partition.

The electric vehicle charging and discharging system includes an electric vehicle charging and discharging DC bus parallel connected to the DC bus of the traction substation, and more than one bidirectional DC-DC charging and discharging motor connected to the electric vehicle charging and discharging DC bus.

The output end of each bidirectional DC-DC charging and discharging motor is connected to the power battery of the electric vehicle.

The output end of each bidirectional DC-DC charging and discharging motor connected to the power battery of the electric vehicle is also connected in parallel with a supercapacitor.

A braking energy recovery type DC traction power supply system of the present utility model has the following advantages:

Making full use of the existing DC traction power supply system, the electric vehicle charging and discharging system based on battery swapping realizes the two-way transmission of energy: when the electric locomotive is running, the energy is provided by the traditional DC traction power supply system and the power battery of the electric vehicle, which can reduce the The drop of the DC bus voltage is small; when the electric locomotive is running under braking, the electric vehicle charging and discharging system based on battery swapping is used to charge the power battery of the electric vehicle, which can reduce the increase of the DC bus voltage; when the DC traction power supply system is under low load And when running at no-load, using the electric vehicle charging and discharging system mainly for battery replacement to charge the power battery of the electric vehicle can improve the power factor of the main substation on the AC side; The system capacity is large enough, and the use of electric vehicle power batteries to supply power to the DC traction power supply system through the electric vehicle charging and discharging system can improve the reliability of the DC traction power supply system; the electric vehicle charging and discharging system mainly uses the existing DC traction power supply system, which can reduce the construction cost of the electric vehicle charging system; in addition, the system also has the function of "shaving peaks and filling valleys", which can improve the economy of the entire system.

Description of drawings

Figure 1 is a schematic structural diagram of an existing DC traction power supply system;

Fig. 2 is a schematic structural diagram of the braking energy recovery type DC traction power supply system of the utility model;

Fig. 3 is a schematic structural diagram of a braking energy recovery DC traction power supply system of the present invention.

in the picture

1: Traction substation 2: Electric locomotive

3: Electric vehicle charging and discharging system 4: AC bus

11: Transformer 12: Rectifier

13: DC bus 14: Catenary

15: Rails 16: Division

31: Electric vehicle charging and discharging DC bus 32: Bidirectional DC-DC charging and discharging motor

Detailed ways

A braking energy recovery type DC traction power supply system of the present invention will be described in detail below with reference to the embodiments and the accompanying drawings.

As shown in Figure 2, a braking energy recovery type DC traction power supply system of the present invention, in the case of multiple traction substations, that is, a braking energy recovery type DC traction power supply system for bilateral power supply, includes two The above traction substation 1 for providing DC power to the electric locomotive 2 adopts a traditional diode rectification DC traction power supply system. Each traction substation 1 is provided with more than one transformer 11 connected to the AC bus 4, and the output side of each transformer 11 is connected to a rectifier 12, and the output sides of all rectifiers 12 are connected to the traction substation 1 where they are located. On the DC bus 13, the positive and negative poles of the DC bus 13 are respectively connected to the catenary 14 and the rail 15, the positive and negative poles of the electric locomotive 2 are respectively connected to the catenary 14 and the rail 15, and each traction substation 1 Each catenary 14 is connected with a partition station 16, and the two ends of the partition station 16 are respectively connected to the positive pole of the corresponding DC bus 13. Wherein, the transformer 11 may be a double-winding transformer, a three-winding transformer, or a three-winding transformer with a phase shift of ±7.5° in which the primary sides are connected in a delta extension. The rectifier 12 may be a six-pulse rectifier, a 12-pulse rectifier or a 24-pulse rectifier. Although two transformers and two rectifiers are shown in Fig. 2, their number is not limited to two. In FIG. 2 , the electric locomotive 2 is a load shared by two adjacent traction substations 1 . The utility model is provided with an electric vehicle charging and discharging system 3 on the DC bus 13 between two adjacent traction substations 1, and the electric vehicle charging and discharging system 3 is connected with the DC buses 13 of two adjacent traction substations 1, thereby A DC ring microgrid is formed within a power supply zone.

The electric vehicle charging and discharging system 3 mainly for battery exchange includes an electric vehicle charging and discharging DC bus 31 connected to the DC buses 13 of two adjacent traction substations 1, and is connected to the electric vehicle charging and discharging DC bus 31 More than one bidirectional DC-DC charging and discharging motor 32 . The output end of each bidirectional DC-DC charging and discharging motor 32 is connected to the power battery of the electric vehicle. Moreover, in order to improve the dynamic performance of the system, a supercapacitor is also connected in parallel at the output end of each bidirectional DC-DC charging and discharging motor 32 connected to the power battery of the electric vehicle.

As shown in Figure 3, a braking energy recovery type DC traction power supply system of the present invention, in the case of a traction substation, that is, a braking energy recovery type DC traction power supply system for unilateral power supply, includes The electric locomotive 2 provides a traction substation 1 for direct current energy. The traction substation 1 is provided with more than one transformer 11 connected to the AC bus 4. The output side of each transformer 11 is connected to a rectifier 12 correspondingly. The output of all rectifiers 12 Both sides are connected to the DC bus 13 of the traction substation 1, the positive and negative poles of the DC bus 13 are respectively connected to the catenary 14 and the rail 15, and the positive and negative poles of the electric locomotive 2 are respectively connected to the catenary 14 and the rail 15 respectively. Rail 15. Wherein, the transformer 11 may be a double-winding transformer, a three-winding transformer, or a three-winding transformer with a phase-shift of ±7.5° whose primary sides are connected in a delta extension. The rectifier 12 may be a six-pulse rectifier, a 12-pulse rectifier or a 24-pulse rectifier. Although two transformers and two rectifiers are shown in Fig. 3, their number is not limited to two. The utility model is provided with an electric vehicle charging and discharging system 3 on the DC bus 13, and the electric vehicle charging and discharging system 3 is connected with the DC bus 13 of the traction substation 1, thereby forming a DC ring microgrid in a power supply partition.

The electric vehicle charging and discharging system 3 includes an electric vehicle charging and discharging DC bus 31 connected in parallel to the DC bus 13 of the traction substation 1, and more than one bidirectional DC-DC connected to the electric vehicle charging and discharging DC bus 31. Charging and discharging motor 32 . The output end of each bidirectional DC-DC charging and discharging motor 32 is connected to the power battery of the electric vehicle. Moreover, in order to improve the dynamic performance of the system, a supercapacitor (not shown in the figure) is also connected in parallel at the output end of each bidirectional DC-DC charging and discharging motor 32 connected to the power battery of the electric vehicle. The utility model uses a traditional diode rectification DC traction power supply system, an electric vehicle charging and discharging system mainly for battery replacement, and an electric vehicle power battery to form a DC ring microgrid in a power supply partition through a DC bus.

The technical scheme shown in Fig. 3 is not only applicable to the braking energy recovery type DC traction power supply system with unilateral power supply, but also suitable for the braking energy recovery type DC traction power supply system with bilateral power supply.

In the braking energy recovery type DC traction power supply system of the present utility model, the DC catenary is connected to the DC output positive pole of the DC traction substation, the overhead catenary is used to supply power to the electric locomotive, and the rail is connected to the DC output negative pole of the DC traction substation. To achieve rail return. In addition to catenary power supply, third rail power supply can also be used. The rails are suspended to reduce galvanic corrosion to underground pipelines.

The working principle of the braking energy recovery type DC traction power supply system of the utility model is that when the braking of the electric locomotive causes the voltage of the DC bus to increase and reaches the defined voltage threshold, the charging and discharging system of the electric vehicle passes the bidirectional DC-DC The charging and discharging machine 32 is used to charge the electric vehicle power battery to prevent the DC bus voltage from exceeding the limit value; when the electric locomotive causes the DC bus voltage to drop to the limited voltage threshold, the electric vehicle power battery passes through the bidirectional DC-DC charging and discharging machine 32 Supply power to the DC bus to prevent the DC bus voltage from falling below the limit value. During the trough and outage period of the electric locomotive, the power supply system is used to charge the power battery of the electric vehicle. While satisfying the charging of the power battery of the electric vehicle, it also solves the problem of the main substation on the AC side of the DC traction power supply system at low load and no load. The problem is that the power factor is greatly reduced. If the capacity of the battery-swapping-based electric vehicle charging and discharging system is large enough, when the AC power grid fails, the battery-swapping-based electric vehicle charging and discharging system can supply power to the electric locomotive.

Therefore, through the coordinated control of the electric vehicle charging and discharging system based on battery swapping and the charging and discharging of the electric vehicle power battery, not only the recovery and utilization of the braking energy of the electric locomotive is realized, the fluctuation of the DC bus voltage is stabilized, and the DC traction power supply system is utilized At low load and no load, it charges the power battery of the electric vehicle, which solves the problem that the power factor of the main substation on the AC side of the DC traction power supply system is greatly reduced. If the capacity of the battery-swapping-based electric vehicle charging and discharging system is large enough, when the AC power grid fails, the battery-swapping-based electric vehicle charging and discharging system can supply power to the electric locomotive, thereby improving the reliability of the DC traction power supply system. At the same time, making full use of the DC traction power supply system greatly reduces the construction cost of the electric vehicle charging system mainly for battery replacement, and has the effect of "shaving peaks and filling valleys" for the power supply system, thereby improving the economy and comprehensive utilization benefits of the entire system.

The charging and discharging control command of the electric vehicle charging and discharging system in the braking energy recovery type DC traction power supply system of the utility model can be given by the control center through the communication system, or can be given according to the DC bus voltage.

Claims (8)

1. A braking energy recovery type DC traction power supply system, comprising more than two traction substations (1) for providing DC power to electric locomotives (2), and each traction substation (1) is equipped with more than one The transformer (11) connected to the AC busbar (4), the output side of each transformer (11) is connected to a rectifier (12), and the output sides of all rectifiers (12) are connected to the traction substation (1 ) on the DC busbar (13), the positive and negative poles of the DC busbar (13) are respectively connected to the catenary (14) and the rail (15), and the positive and negative poles of the electric locomotive (2) are respectively connected to catenary (14) and rail (15), each traction substation (1) catenary (14) is connected with a partition station (16), and the two ends of the partition station (16) are also connected to the corresponding The positive pole of the DC busbar (13) is characterized in that an electric vehicle charging and discharging system (3) is set on the DC busbar (13) between two adjacent traction substations (1), and the electric vehicle charging The discharge system (3) is connected with the DC bus bars (13) of two adjacent traction substations (1), thereby forming a DC ring micro-grid in a power supply partition. 2. A braking energy recovery type DC traction power supply system according to claim 1, characterized in that the electric vehicle charging and discharging system (3) includes two adjacent traction substations (1) connected An electric vehicle charging and discharging DC bus (31) on the DC bus (13), and more than one bidirectional DC-DC charging and discharging motor (32) connected to the electric vehicle charging and discharging DC bus (31). 3. A braking energy recovery type DC traction power supply system according to claim 2, characterized in that the output end of each bidirectional DC-DC charging and discharging motor (32) is connected to a power battery of an electric vehicle. 4. A braking energy recovery type DC traction power supply system according to claim 3, characterized in that, the output end of each of the bidirectional DC-DC charging and discharging motors (32) connected to the power battery of the electric vehicle is also Connect supercapacitors in parallel. 5. A braking energy recovery type DC traction power supply system, comprising a traction substation (1) for providing DC power to an electric locomotive (2), and the traction substation (1) is provided with more than one AC bus (4), the output side of each transformer (11) is connected to a rectifier (12), and the output sides of all rectifiers (12) are connected to the DC busbar ( 13), the positive and negative poles of the DC bus (13) are respectively connected to the catenary (14) and the rail (15), and the positive and negative poles of the electric locomotive (2) are respectively connected to the catenary (14) And steel rail (15), it is characterized in that, be provided with electric vehicle charge and discharge system (3) on described direct current busbar (13), the direct current busbar (13) of electric vehicle charge and discharge system (3) and traction substation (1) ) are connected to form a DC ring microgrid in a power supply zone. 6. A braking energy recovery type DC traction power supply system according to claim 5, characterized in that the electric vehicle charging and discharging system (3) includes a DC bus ( 13) the electric vehicle charging and discharging DC busbar (31), and more than one bidirectional DC-DC charging and discharging motor (32) connected to the electric vehicle charging and discharging DC busbar (31). 7. A braking energy recovery type DC traction power supply system according to claim 6, characterized in that the output end of each bidirectional DC-DC charging and discharging motor (32) is connected to a power battery of an electric vehicle. 8. A braking energy recovery type DC traction power supply system according to claim 7, characterized in that, the output end of each of the bidirectional DC-DC charging and discharging motors (32) connected to the power battery of the electric vehicle is also Connect supercapacitors in parallel.

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