阅读说明：本技术 基于模块化anpc三电平逆变器的地铁双向变流装置 (Subway bidirectional converter device based on modular ANPC three-level inverter ) 是由 仇志凌 胡磊磊 张明 张勇 芮国强 李晓天 万里强 石泉 于 2020-07-14 设计创作，主要内容包括：本发明公开了基于模块化ANPC三电平逆变器的地铁双向变流装置包括两组并联的ANPC三电平逆变模块组、变压器；逆变模块组将直流电转换成低压交流电至变压器,变压器输出中压交流电至中压网；每个逆变模块组包括至少一路ANPC三电平逆变模块；每个ANPC三电平逆变模块输出端通过与之串联的交流滤波电感连接至副边双绕组升压变压器的对应副边绕组。本发明能够彻底解决NPC三电平逆变器的长回路关断电压尖峰过高问题,提高装置可靠性,模块化任意数量并联灵活覆盖不同电流等级需求,专门的滤波电感降低了变压器噪音和成本。(The invention discloses a subway bidirectional converter based on a modular ANPC three-level inverter, which comprises two groups of ANPC three-level inverter module groups and a transformer, wherein the two groups of ANPC three-level inverter module groups are connected in parallel; the inversion module group converts the direct current into low-voltage alternating current to the transformer, and the transformer outputs medium-voltage alternating current to the medium-voltage network; each inversion module group comprises at least one path of ANPC three-level inversion module; the output end of each ANPC three-level inversion module is connected to the corresponding secondary winding of the secondary double-winding boosting transformer through an alternating current filter inductor connected in series with the output end of each ANPC three-level inversion module. The invention can thoroughly solve the problem of overhigh peak of the turn-off voltage of the long loop of the NPC three-level inverter, improves the reliability of the device, modularizes any number of parallel connections, flexibly covers the requirements of different current levels, and reduces the noise and the cost of the transformer by the special filter inductor.)

1. Subway bidirectional converter device based on three level inverter of modularization ANPC, its characterized in that: the power supply comprises two sets of ANPC three-level inversion module groups connected in parallel and a secondary side double-winding step-up transformer; the ANPC three-level inversion module group is connected with a direct-current power grid to convert direct current into low-voltage alternating current and transmit the low-voltage alternating current to the secondary double-winding step-up transformer, and the secondary double-winding step-up transformer outputs medium-voltage alternating current to the medium-voltage power grid;

each ANPC three-level inversion module group comprises at least one path of ANPC three-level inversion module; the output end of each ANPC three-level inversion module is connected to a corresponding secondary winding of the secondary double-winding boosting transformer through an alternating current filter inductor connected in series with the output end of each ANPC three-level inversion module; and the AC outputs of the ANPC three-level inversion modules in the same group are connected to the same secondary winding of the transformer after passing through the filter inductor.

2. A subway bidirectional converter apparatus based on modular ANPC three-level inverter as claimed in claim 1, characterized in that: each phase bridge arm of the ANPC three-level inverter module consists of three half-bridge IGBT modules; the IGBT module No. 1 comprises switching elements T1x and T5x, diodes D1x and D5x, wherein the T1x and the T5x are connected with D1x and D5x in an anti-parallel mode respectively; the IGBT module No. 2 comprises switching elements T2x and T3x, diodes D2x and D3x, wherein the T2x and the T3x are connected with D2x and D3x in an antiparallel mode respectively; the IGBT module No. 3 comprises switching elements T4x and T6x, diodes D4x and D6x, wherein the T4x and the T6x are connected in an anti-parallel mode with the D4x and the D6x respectively; wherein x represents three phases of a, b and c.

3. A subway bidirectional converter apparatus based on modular ANPC three-level inverter as claimed in claim 1, characterized in that: the secondary side double-winding step-up transformer is a three-phase three-column type, the high-voltage side adopts a triangular connection method, and the low-voltage side adopts two groups of three-phase star-shaped connection windings.

4. A subway bidirectional converter apparatus based on modular ANPC three-level inverter as claimed in claim 1, characterized in that: the alternating current filter inductor is a three-phase three-column filter inductor.

Technical Field

The invention relates to the technical field of urban rail transit power supply systems, in particular to a subway bidirectional converter device based on a modular ANPC three-level inverter.

Background

In recent years, urban rail transit in China develops very rapidly, and in order to respond to national energy conservation and emission reduction policies, a diode rectifier set and regenerative braking energy feedback device mode is gradually popularized in a domestic subway traction power supply system to achieve the purpose of reducing energy consumption. However, the voltage of the direct current traction network output by the diode rectifier unit drops greatly along with the increase of the load, so that the power supply distance is short, the number of traction power supply stations needs to be increased, and the subway construction cost is increased. Meanwhile, the added regenerative braking energy feedback device further increases the complexity and the occupied area of the whole set of traction power supply system, and improves the overall construction and operation and maintenance cost.

With the development of high-power electronic converter technology, a bidirectional converter device integrating functions of rectification, traction, power supply and inversion energy feedback is gradually applied to subways. Several domestic enterprises have conducted beneficial research and exploration on subway bidirectional converter devices. The two patents of a track traffic bidirectional converter cabinet (application number: 201710039531.5) of Xuzhou middlings large transmission and automation company Limited in the prior art 1 and a track traffic traction power supply system and a control method (application number: 201710984413.1) of a patent of Zhou Shi electric power generation company Limited in the prior art 2 are representative.

In terms of circuit structure, in prior art 1, "two-way converter cabinet for rail transit" adopts four diode Neutral Point Clamped (NPC) three-level inverters with ac and dc sides directly connected in parallel, so that an ac filter inductor is eliminated, and a leakage inductor of a high-impedance transformer is adopted to filter a switching ripple. The three-level inverter has the advantages of small switching ripple, low loss and high switching frequency, but the NPC three-level inverter has a long commutation loop under the rectification working condition, and the IGBT turn-off voltage spike is high, so that the reliability of the device is influenced. And secondly, although the size of the bidirectional converter cabinet can be reduced by eliminating the filter inductor, the size and the noise of the adopted high-impedance transformer are large, and the hidden trouble of uneven current distribution exists among the four NPC three-level inverters.

Disclosure of Invention

1. The technical problem to be solved is as follows:

aiming at the technical problems, the invention provides a subway bidirectional converter device based on a modular ANPC three-level inverter, which can thoroughly solve the problem of overhigh peak of turn-off voltage of a long-loop IGBT (insulated gate bipolar translator) of the NPC three-level inverter and improve the reliability of the device; the modularized parallel connection can flexibly cover different current grade requirements; the special filter inductor reduces the noise and the volume of the transformer and improves the current sharing degree.

2. The technical scheme is as follows:

subway bidirectional converter device based on three level inverter of modularization ANPC, its characterized in that: the power supply comprises two sets of ANPC three-level inversion module groups connected in parallel and a secondary side double-winding step-up transformer; the ANPC three-level inversion module group is connected with a direct-current power grid to convert direct current into low-voltage alternating current and transmit the low-voltage alternating current to the secondary double-winding step-up transformer, and the secondary double-winding step-up transformer outputs medium-voltage alternating current to the medium-voltage power grid;

each ANPC three-level inversion module group comprises at least one path of ANPC three-level inversion module; the output end of each ANPC three-level inversion module is connected to a corresponding secondary winding of the secondary double-winding boosting transformer through an alternating current filter inductor connected in series with the output end of each ANPC three-level inversion module; and the AC outputs of the ANPC three-level inversion modules in the same group are connected to the same secondary winding of the transformer after passing through the filter inductor.

Furthermore, each phase bridge arm of the ANPC three-level inverter module is composed of three half-bridge IGBT modules; the IGBT module No. 1 comprises switching elements T1x and T5x, diodes D1x and D5x, wherein the T1x and the T5x are connected with D1x and D5x in an anti-parallel mode respectively; the IGBT module No. 2 comprises switching elements T2x and T3x, diodes D2x and D3x, wherein the T2x and the T3x are connected with D2x and D3x in an antiparallel mode respectively; the IGBT module No. 3 comprises switching elements T4x and T6x, diodes D4x and D6x, wherein the T4x and the T6x are connected in an anti-parallel mode with the D4x and the D6x respectively; wherein x represents three phases of a, b and c.

Furthermore, the secondary side double-winding step-up transformer is a three-phase three-column type, the high-voltage side adopts a triangular connection method, and the low-voltage side adopts two groups of three-phase star-shaped connection windings.

Further, the alternating current filter inductor is a three-phase three-column filter inductor.

3. Has the advantages that:

(1) the device has high power density: the ANPC three-level inverter topology has the advantages of small output ripple, low loss and high switching frequency, and the size of the device is effectively reduced.

(2) The device has high reliability: the ANPC three-level inverter topology thoroughly solves the problem that the peak of turn-off voltage of the long-loop IGBT of the traditional NPC three-level inverter topology is too high.

(3) This device can cover different power demands in a flexible way: any number of the modular ANPC three-level inversion modules are connected in parallel, so that different current requirements can be met.

(4) The current waveform output by the device has good quality: and carrier phase shift control is adopted between the two groups of inversion modules, so that the effect of multiplying the switching frequency is achieved, the switching ripple current injected into a power grid is reduced, and the current waveform quality is improved.

(5) This device low noise, low cost: compared with a high-impedance transformer, the scheme of the alternating current filter inductor and the common transformer is low in noise and cost.

Drawings

FIG. 1 is an overall circuit topology of the present apparatus;

FIG. 2 is a circuit topology diagram of an ANPC three-level inverter module employed in the present invention;

FIG. 3 is a diagram of an example of bridge arm device layout and connection according to the present invention.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 1, a subway bidirectional converter device based on a modular ANPC three-level inverter is characterized in that: the power supply comprises two sets of ANPC three-level inversion module groups connected in parallel and a secondary side double-winding step-up transformer; the ANPC three-level inversion module group is connected with a direct-current power grid to convert direct current into low-voltage alternating current and transmit the low-voltage alternating current to the secondary double-winding step-up transformer, and the secondary double-winding step-up transformer outputs medium-voltage alternating current to the medium-voltage power grid;

each ANPC three-level inversion module group comprises at least one path of ANPC three-level inversion module; the output end of each ANPC three-level inversion module is connected to a corresponding secondary winding of the secondary double-winding boosting transformer through an alternating current filter inductor connected in series with the output end of each ANPC three-level inversion module; and the AC outputs of the ANPC three-level inversion modules in the same group are connected to the same secondary winding of the transformer after passing through the filter inductor.

As shown in fig. 2, further, each phase bridge arm of the ANPC three-level inverter module is formed by three half-bridge IGBT modules; the IGBT module No. 1 comprises switching elements T1x and T5x, diodes D1x and D5x, wherein the T1x and the T5x are connected with D1x and D5x in an anti-parallel mode respectively; the IGBT module No. 2 comprises switching elements T2x and T3x, diodes D2x and D3x, wherein the T2x and the T3x are connected with D2x and D3x in an antiparallel mode respectively; the IGBT module No. 3 comprises switching elements T4x and T6x, diodes D4x and D6x, wherein the T4x and the T6x are connected in an anti-parallel mode with the D4x and the D6x respectively; wherein x represents three phases of a, b and c.

Furthermore, the secondary side double-winding step-up transformer is a three-phase three-column type, the high-voltage side adopts a triangular connection method, and the low-voltage side adopts two groups of three-phase star-shaped connection windings.

Further, the alternating current filter inductor is a three-phase three-column filter inductor.