Single-phase and three-phase conversion system based on MMC units

A flow system, single-phase AC technology, applied in the direction of converting AC power input to AC power output, electrical components, output power conversion devices, etc., can solve the problems affecting the efficiency of the traction system, the large size of the traction transformer, and the increase of losses, etc. Achieve advanced technology, improved reliability and availability, and high efficiency

Inactive Publication Date: 2014-08-20
SOUTHWEST JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traction transformers are bulky and heavy, and increase losses a

Method used

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  • Single-phase and three-phase conversion system based on MMC units
  • Single-phase and three-phase conversion system based on MMC units
  • Single-phase and three-phase conversion system based on MMC units

Examples

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Embodiment

[0020] figure 1 It is shown that a specific embodiment of the present invention is: the system is composed of n MMC units. One side of each MMC unit is a single-phase inverter, and the other side is a three-phase inverter, and the DC links of the two inverters are connected in parallel. The n MMC units are connected in series on the single-phase side to implement voltage equalization measurement and control, and the three-phase sides are independent and electrically insulated from each other. Each unit is composed of ten bridge arms Ap, An, Bp, Bn, Cp, Cn, Dp, Dn, Ep and En with the same structure, among which four bridge arms Dp, Dn, Ep and En form a single-phase inverter Inverter, 6 bridge arms Ap, An, Bp, Bn, Cp and Cn constitute a three-phase inverter; each bridge arm is composed of p power modules PM with the same structure connected in series with the bridge arm inductance L; the power module PM It is a single-phase half-bridge structure consisting of an IGBT half-brid...

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PUM

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Abstract

Disclosed is a single-phase and three-phase conversion system based on MMC units. Each MMC unit is formed by connecting 10 bridge arms, wherein four bridge arms constitute a single-phase inverter and form a single-phase alternating-current port, and the other six bridge arms constitute a three-phase inverter and form a three-phase alternating-current port. Each MMC bridge arm is formed by connecting p structurally-identical power modules and an MMC bridge arm inductor L in series. The power modules are of a single-phase half bridge structure and are respectively composed of an IGBT half bridge and a direct-current energy storage capacitor. The single-phase alternating-current ports of n MMC units are connected in series with a high-voltage system. The three-phase alternating-current ports of the MMC units are insulated from each other and are independently connected with a low-voltage system. Two-way active power flow between the single-phase high-voltage system and the three-phase low-voltage system is realized. A matching transformer is omitted, which enables the system to have the advantages of small size, light weight, high efficiency, and less investment. The single-phase and three-phase conversion system based on MMC units is advanced and reliable in technology, and is easy to implement.

Description

technical field [0001] The invention relates to a single-phase three-phase current conversion system based on a modular multilevel converter (MMC, modular multilevel converter for short), in particular to the traction drive system of an electrified railway train, and can also be used in frequency conversion occasions. Background technique [0002] Compared with DC traction motors, AC traction motors have the advantages of high power density, low price, simplicity and reliability, and good anti-idling performance, so they are replacing DC motors as the main power source for traction in electrified railways and rail transit. Electrified railways use single-phase power supply, and AC traction motors need to be driven by three-phase inverters. In order to realize this conversion function, the electric locomotive or EMU is equipped with an AC-DC-AC traction converter, which converts single-phase AC to DC first, and then converts it to three-phase AC through an inverter. The rate...

Claims

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Application Information

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IPC IPC(8): H02M5/458
Inventor 李群湛郭育华黄小红夏焰坤李亚楠丁菊霞
Owner SOUTHWEST JIAOTONG UNIV
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