CN108599207A - A kind of energy storage topological structure applying to high speed rail system - Google Patents

Abstract

The present invention provides an energy storage topology applied to high-speed railway systems. The energy storage topology is a three-phase electrical energy storage topology, and each phase of the electrical energy storage topology is divided into two parts: an upper bridge arm and a lower bridge arm. , the upper bridge arm and the lower bridge arm are respectively composed of n multilevel converter modules (MMC), n power electronic transformer modules (ETM), n battery modules (U) and a snubber inductor, where n is greater than 1 positive integer of . Each phase is electrically connected in series between the multilevel converter module (MMC) and the multilevel converter module (MMC), and between the multilevel converter module (MMC) and the power electronic transformer module (ETM) In parallel connection, the power electronic transformer module (ETM) is connected in parallel with the battery module (U). Compared with the prior art, the invention enables the regenerative energy to be fully and rationally utilized, improves the power quality of the power grid during braking, and has the advantages of energy saving and environmental protection.

Description

A topology of energy storage for high-speed railway system

technical field

The invention belongs to the technical field of power electronics and relates to an energy storage topological structure applied to a high-speed railway system.

Background technique

In recent years, with the rapid development of my country's high-speed railway industry, my country has become the country with the longest high-speed railway line in the world, and its installed power and departure density are also among the top in the world. High-speed railway has the characteristics of strong transportation capacity, comfortable ride, energy saving and environmental protection, but it is also one of the few important loads directly connected to the power system. Compared with traditional AC-DC electric locomotives, high-speed railways have the characteristics of large traction load power, high reliability requirements, and long time for taking current. Due to the high-speed railway has the characteristics of fast running speed and large load power, the regenerative braking energy generated by it is also considerable.

When the high-speed train brakes, it will generate braking energy. At present, the regenerative braking energy generated by the high-speed railway mainly includes two ways of utilization: one is absorbed by the high-speed train that is being towed in the same power supply section; the other is directly sent back to the power system. However, since the electric locomotive is a single-phase asymmetric load, the regenerative braking energy fed back to the power system contains a large number of harmonic components and negative sequence components, which seriously affects the safe operation of the power system. A punitive charge is adopted for electricity, that is, the electricity sent back to the grid is equal to the electricity consumed, which is the so-called "backward metering", which undoubtedly increases the operating cost of the high-speed railway. In order to meet the growing demand for high-speed railway passenger transportation and cope with rising operation and maintenance costs, research on the utilization of regenerative braking energy for electrified railways is of great significance, which is also in line with the theme of energy conservation and environmental protection that is being raised in the world today.

At present, in the regenerative braking process of trains, the regenerative braking energy is generally stored in storage devices. The control system of the energy storage device judges that the train is in the regenerative braking condition according to conditions such as catenary voltage and current direction. The link starts, and the regenerative braking energy is stored in the energy storage device. And when the train is working in acceleration, climbing and other working conditions that consume a lot of power, the energy conversion link starts again, and at this time the electric energy in the energy storage device is released for use. According to different energy storage devices, it can be divided into battery energy storage, superconducting energy storage, flywheel energy storage and supercapacitor energy storage, etc., because MMC has a highly modular structure, has a common DC bus, and retains the traditional multi-level conversion Therefore, when MMC is used for energy storage, it is not only energy-saving and environmentally friendly, but also improves the power quality during braking, and at the same time makes the control of the capacitor voltage of the MMC sub-module more flexible.

However, due to the high application voltage level of the high-speed railway system, which is 27.5kV, and the battery pack used for energy storage in the energy storage type MMC is mainly used for low-voltage level, which is 36V-720V, so it cannot be directly connected to the high-speed railway In the system, although there is currently a structure that uses a power frequency transformer to step down the voltage to complete the step-down energy storage, but this topology has a series of shortcomings such as high cost and large installation space, which leads to application limitations.

Contents of the invention

In order to solve the above problems, the present invention provides an energy storage topology applied to a high-speed railway system.

The present invention specifically adopts the following technical solutions: an energy storage topology applied to a high-speed railway system, the energy storage topology is a three-phase electric energy storage topology, and each phase of the electric energy storage topology is divided into an upper bridge arm and a lower bridge arm. The two parts of the bridge arm are characterized in that: the upper bridge arm and the lower bridge arm are respectively composed of n multilevel converter modules (MMC), n power electronic transformer modules (ETM), n battery modules (U) and a Snubber inductance, n is a positive integer greater than 1; the second interface (a12) of the first multilevel converter module (MMC1) and the first interface (a21) of the second multilevel converter module (MMC2) ) connection, n multilevel converter modules (MMC) are sequentially connected in series according to the connection mode of the first multilevel converter module (MMC1) and the second multilevel converter module (MMC2); the first The third interface (a13) of the multilevel converter module (MMC1) is connected to the first interface (b11) of the first power electronic transformer module (ETM1), and the first interface (b11) of the first multilevel converter module (MMC1) The second interface (a12) is connected to the second interface (b12) of the first power electronic transformer module (ETM1), and n multilevel converter modules (MMC) and n power electronic transformer modules (ETM) are connected according to the first A multilevel converter module (MMC1) is connected in parallel with the first power electronic transformer module (ETM1) sequentially; the third interface (b13) of the first power electronic transformer module (ETM1) is connected to the first battery module ( U1), the fourth interface (b14) of the first power electronic transformer module (ETM1) is connected to the negative pole of the first battery module (U1), n power electronic transformer modules (ETM) and n battery modules (U ) are sequentially connected in parallel according to the connection mode of the first power electronic transformer module (ETM1) and the first battery module (U1).

The present invention further includes the following preferred solutions: the first multilevel converter module (MMC1) is composed of a first full-control switching device (S11), a second full-control switching device (S12) and a first capacitor (C11) Composition; wherein, the first full-control switch device (S11) is connected in series with the second full-control switch device (S12); the first capacitor (C11) is connected with the first full-control switch device (S11) and the second full-control switch device (S12) ) series branches in parallel.

The first power electronic transformer module (ETM1) consists of the third to eighteenth full-control switching devices (S13, S14, S15, S16, S17, S18, S19, S20), the first filter inductor (SL11), The second filter inductor (SL12), the first transformer (T11) and the second capacitor (C12); wherein, the third full-control switch device (S13) is connected in series with the fourth full-control switch device (S14); the fifth full-control switch device The switch device (S15) is connected in series with the sixth full-control switch device (S16); the series branch of the third full-control switch device (S13) and the fourth full-control switch device (S14) is connected with the fifth full-control switch device (S15) It is connected in parallel with the series branch of the sixth full-control switch device (S16); the seventh full-control switch device (S17) is connected in series with the eighth full-control switch device (S18); the ninth full-control switch device (S19) is connected with the tenth full-control switch device The control switch device (S20) is connected in series; the series branch of the seventh full control switch device (S17) and the eighth full control switch device (S18) is connected with the ninth full control switch device (S19) and the tenth full control switch device (S20) ) series branches in parallel; the series connection nodes of the third full-control switch device (S13) and the fourth full-control switch device (S14), the first filter inductor (SL11), and the primary side of the first transformer (T11) ( TS1), the fifth full-control switch device (S15) and the sixth full-control switch device (S16) are serially connected in series; the seventh full-control switch device (S17) and the eighth full-control switch device (S18) The series connection node of the node connected in series, the secondary side (TS2) of the first transformer (T11), the second filter inductor (SL12), the ninth fully controlled switch device (S19) and the tenth fully controlled switch device (S20) sequentially connected in series.

The first multi-level converter module (MMC1) is used to perform multi-level rectification control of the current from the high-voltage line side to the low-voltage line side when the train brakes, and the first battery module (U1 ) when carrying out discharge energy supply, carry out the multi-level inverter control of the current from the low-voltage line side to the high-voltage line side; the first power electronic transformer module (ETM1) is used to reduce the high-voltage DC voltage to low-voltage DC voltage and charge and store energy for the first battery module (U1), and raise the low-voltage DC voltage to a high-voltage DC voltage when the first battery module (U1) performs a discharge function; the third The sixth full-control switching device (S13, S14, S15, S16) is used to rectify the alternating current into direct current through rectification control when the train is braking, and pass through when the first battery module (U1) performs the discharging function. The inverter control inverts the DC power into AC power; the first transformer (T11) is used to reduce the AC voltage when the train brakes, and increase the AC voltage when the first battery module (U1) performs the discharge function ; The seventh to tenth full-control switching devices (S17, S18, S19, S20) are used to invert the direct current into alternating current through inverter control when the train is braked, and in the first battery module (U1) rectifies the alternating current into direct current through rectification control when performing the discharging function; the first battery module (U1) is used for charging and storing energy when the train brakes, and is used for the discharging function.

Compared with the existing technology, the advantage of the present invention is that it saves the power frequency transformer in other energy storage methods, and proposes the innovative point of combining the multilevel converter module and the power electronic transformer module, and the battery module passes through the power electronic transformer The module is connected to the sub-modules of the multi-level converter module, and the regenerative energy is effectively distributed to the sub-modules of the multi-level converter module for storage; the invention directly connects the general battery module with a lower working voltage level The traction network with higher voltage level does not use power frequency transformers, which effectively reduces the cost and installation space of energy storage equipment.

Description of drawings

Fig. 1: is the topological structure diagram of the present invention.

Detailed ways

In order to facilitate those of ordinary skill in the art to understand and implement the present invention, the present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the implementation examples described here are only used to illustrate and explain the present invention, and are not intended to limit this invention.

Please see Fig. 1, the technical solution adopted by the system of the present invention is an energy storage topology applied to high-speed railway systems, which is characterized in that it includes: the upper bridge arm and the lower bridge arm are respectively commutated by n multi-level Converter module (MMC), n power electronic transformer modules (ETM), n battery modules (U) and a snubber inductance, n is a positive integer greater than 1; the first multilevel converter module (MMC1) The second interface (a12) is connected to the first interface (a21) of the second multilevel converter module (MMC2), and n multilevel converter modules (MMC) are connected according to the first multilevel converter module (MMC1) and the second multilevel converter module (MMC2) are sequentially connected in series; the third interface (a13) of the first multilevel converter module (MMC1) is connected to the first power electronic transformer module ( The first interface (b11) of ETM1) is connected, the second interface (a12) of the first multilevel converter module (MMC1) is connected with the second interface (b12) of the first power electronic transformer module (ETM1), n According to the connection mode between the first multilevel converter module (MMC1) and the first power electronic transformer module (ETM1) between the n multilevel converter modules (MMC) and the n power electronic transformer modules (ETM) Parallel connection; the third interface (b13) of the first power electronic transformer module (ETM1) is connected to the positive pole of the first battery module (U1), and the fourth interface (b14) of the first power electronic transformer module (ETM1) is connected to the first The negative pole of the battery module (U1) is connected, and the connection between n power electronic transformer modules (ETM) and n battery modules (U) is in order according to the connection mode between the first power electronic transformer module (ETM1) and the first battery module (U1) connected in parallel.

The first multilevel converter module (MMC1) is composed of a first full-control switching device (S11), a second full-control switching device (S12) and a first capacitor (C11); wherein, the first full-control The switch device (S11) is connected in series with the second full control switch device (S12); the first capacitor (C11) is connected in parallel with the series branch of the first full control switch device (S11) and the second full control switch device (S12).

The first power electronic transformer module (ETM1) consists of the third to eighteenth full-control switching devices (S13, S14, S15, S16, S17, S18, S19, S20), the first filter inductor (SL11), The second filter inductor (SL12), the first transformer (T11) and the second capacitor (C12); wherein, the third full-control switch device (S13) is connected in series with the fourth full-control switch device (S14); the fifth full-control switch device The switch device (S15) is connected in series with the sixth full-control switch device (S16); the series branch of the third full-control switch device (S13) and the fourth full-control switch device (S14) is connected with the fifth full-control switch device (S15) It is connected in parallel with the series branch of the sixth full-control switch device (S16); the seventh full-control switch device (S17) is connected in series with the eighth full-control switch device (S18); the ninth full-control switch device (S19) is connected with the tenth full-control switch device The control switch device (S20) is connected in series; the series branch of the seventh full control switch device (S17) and the eighth full control switch device (S18) is connected with the ninth full control switch device (S19) and the tenth full control switch device (S20) ) series branches in parallel; the series connection nodes of the third full-control switch device (S13) and the fourth full-control switch device (S14), the first filter inductor (SL11), and the primary side of the first transformer (T11) ( TS1), the fifth full-control switch device (S15) and the sixth full-control switch device (S16) are serially connected in series; the seventh full-control switch device (S17) and the eighth full-control switch device (S18) The series connection node of the node connected in series, the secondary side (TS2) of the first transformer (T11), the second filter inductor (SL12), the ninth fully controlled switch device (S19) and the tenth fully controlled switch device (S20) sequentially connected in series.

The first multi-level converter module (MMC1) of the present invention is used to perform multi-level rectification control of current from the high-voltage line side to the low-voltage line side when the train brakes, and in the first battery module ( U1) performs multi-level inverter control of the current from the low-voltage line side to the high-voltage line side when performing discharge energy supply; the first power electronic transformer module (ETM1) is used to reduce the high-voltage DC voltage when the train brakes charging and storing energy for the first battery module (U1) for the low-voltage DC voltage, and raising the low-voltage DC voltage to a high-voltage DC voltage when the first battery module (U1) performs a discharge function; the second The third to sixth full-control switching devices (S13, S14, S15, S16) are used to rectify the alternating current into direct current through rectification control when the train brakes, and when the first battery module (U1) performs the discharge function Invert the DC power into AC power through inverter control; the first transformer (T11) is used to reduce the AC voltage when the train is braking, and increase the AC voltage when the first battery module (U1) performs the discharge function Voltage; the seventh to tenth full-control switching devices (S17, S18, S19, S20) are used to invert direct current into alternating current through inverter control when the train brakes, and the first storage battery The module (U1) rectifies the alternating current into direct current through rectification control when performing the discharging function; the first storage battery module (U1) is used for charging and storing energy when the train is braking, and is used for the discharging function.

In this embodiment, the upper bridge arm and the lower bridge arm are respectively composed of n=7 multi-level converter modules, and the multi-level converter modules are FD800R45KL3-K_B5 modules; the third to tenth eighth A full control switch device (S13, S14, S15, S16, S17, S18, S19, S20) selects the FD800R45KL3-K_B5 module.

When the train brakes, the current on the high voltage side of the three-phase AC is controlled by multi-level rectification through the three-phase multilevel converter module (MMC) of the present invention, and the high voltage is converted by the power electronic transformer module (ETM) of the present invention. The side direct current is reduced to the low-voltage side direct current, and the battery module (U) of the present invention is used to charge and store energy; when the battery module (U) of the present invention performs a discharge function, the low-voltage side is converted to The direct current is raised to the high-voltage side direct current, and the multi-level inverter control is carried out through the three-phase multi-level converter module (MMC) of the present invention, and finally the electric energy stored in the battery module (U) of the present invention is delivered to the three-phase Phase AC high voltage side.

Although this article mostly uses the first multi-level converter module (MMC1), the first fully-controlled switching device (S11), the second fully-controlled switching device (S12), the first capacitor (C11), and the first Power electronic transformer module (ETM1), the third to eighteenth fully-controlled switching devices (S13, S14, S15, S16, S17, S18, S19, S20), the first filter inductor (SL11), the second filter inductor ( SL12), the third to eighteenth full-control switch devices (S13, S14, S15, S16, S17, S18, S19, S20) of the first transformer (T11), the first filter inductor (SL11), the second filter inductor (SL12), the first transformer (T11), the second capacitor (C12), the second capacitor (C12), the first battery module (U1) and other terms, but the possibility of using other terms is not excluded. These terms are only used to describe the essence of the present invention more conveniently, and it is against the spirit of the present invention to interpret them as any additional limitation.

It should be understood that the above-mentioned descriptions for the preferred embodiments are relatively detailed, and should not therefore be considered as limiting the scope of the patent protection of the present invention. Within the scope of protection, replacements or modifications can also be made, all of which fall within the protection scope of the present invention, and the scope of protection of the present invention should be based on the appended claims.

Claims (3)

1. An energy storage topology applied to a high-speed railway system, the energy storage topology is a three-phase electric energy storage topology, and each phase electric energy storage topology is divided into an upper bridge arm and a lower bridge arm, characterized in that , including: the upper bridge arm and the lower bridge arm are respectively composed of n multilevel converter modules (MMC), n power electronic transformer modules (ETM), n battery modules (U) and a snubber inductor, n is A positive integer greater than 1; The second interface (a12) of the first multilevel converter module (MMC1) is connected to the first interface (a21) of the second multilevel converter module (MMC2), n multilevel converter modules (MMC) is sequentially connected in series according to the connection mode of the first multilevel converter module (MMC1) and the second multilevel converter module (MMC2); The three interfaces (a13) are connected to the first interface (b11) of the first power electronic transformer module (ETM1), and the second interface (a12) of the first multilevel converter module (MMC1) is connected to the first power electronic transformer module The second interface (b12) of (ETM1) is connected, between n multilevel converter modules (MMC) and n power electronic transformer modules (ETM) according to the first multilevel converter module (MMC1) and The connection mode of the first power electronic transformer module (ETM1) is sequentially connected in parallel; the third interface (b13) of the first power electronic transformer module (ETM1) is connected to the positive pole of the first battery module (U1), and the first power electronic transformer module The fourth interface (b14) of (ETM1) is connected to the negative pole of the first battery module (U1), and the connection between n power electronic transformer modules (ETM) and n battery modules (U) is based on the first power electronic transformer module (ETM1 ) and the first battery module (U1) are sequentially connected in parallel. 2. The energy storage topology used in high-speed railway systems according to claim 1, characterized in that: the first multilevel converter module (MMC1) is composed of a first full-control switching device (S11), The second full-control switch device (S12) and the first capacitor (C11) are formed; wherein, the first full-control switch device (S11) is connected in series with the second full-control switch device (S12); the first capacitor (C11) is connected in parallel with the series branch of said first fully controlled switching device (S11) and said second fully controlled switching device (S12). 3. The energy storage topology applied to high-speed railway systems according to claim 1, characterized in that: the first power electronic transformer module (ETM1) consists of the third to eighteenth fully-controlled switching devices (S13 , S14, S15, S16, S17, S18, S19, S20), the first filter inductor (SL11), the second filter inductor (SL12), the first transformer (T11) and the second capacitor (C12); wherein, the first The third full-control switch device (S13) is connected in series with the fourth full-control switch device (S14); the fifth full-control switch device (S15) is connected in series with the sixth full-control switch device (S16); the third full-control switch device (S13) The series branch of the fourth full-control switch device (S14) is connected in parallel with the series branch of the fifth full-control switch device (S15) and the sixth full-control switch device (S16); the seventh full-control switch device (S17) is connected with The eighth full-control switch device (S18) is connected in series; the ninth full-control switch device (S19) is connected in series with the tenth full-control switch device (S20); the seventh full-control switch device (S17) and the eighth full-control switch device (S18 ) in parallel with the series branch of the ninth full-control switch device (S19) and the tenth full-control switch device (S20); the third full-control switch device (S13) and the fourth full-control switch device (S14) The series connection junction of the first filter inductor (SL11), the primary side (TS1) of the first transformer (T11), the fifth fully controlled switching device (S15) and the sixth fully controlled switching device (S16) The points are connected in series; the series connection node of the seventh full-control switch device (S17) and the eighth full-control switch device (S18), the secondary side (TS2) of the first transformer (T11), the second filter inductor (SL12), The series connection nodes of the ninth full-control switch device ( S19 ) and the tenth full-control switch device ( S20 ) are serially connected in series.