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Cascade multi-level converter based on non-isolated back-to-back topology and control strategy thereof

A cascading multi-level and control strategy technology, which is applied in the direction of power transmission AC network, conversion of AC power input to AC power output, and conversion of AC power input to DC power output, etc., can solve the problem of increased volume and cost of flexible interface devices, Difficult distribution network large-scale application and other issues

Pending Publication Date: 2022-04-15
XI AN JIAOTONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the medium and high voltage field, the cascaded H-bridge back-to-back topology has attracted much attention due to its advantages of convenient control and easy expansion; this topology is composed of basic modules cascaded to achieve multi-level, and its basic modules are composed of front and rear H-bridges and intermediate frequency transformers. Isolated dual active bridge (DAB), but the introduction of DAB greatly increases the size and cost of the flexible interface device, making it difficult to apply on a large scale in the distribution network

Method used

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  • Cascade multi-level converter based on non-isolated back-to-back topology and control strategy thereof
  • Cascade multi-level converter based on non-isolated back-to-back topology and control strategy thereof
  • Cascade multi-level converter based on non-isolated back-to-back topology and control strategy thereof

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specific Embodiment 1

[0070] Set the simulation parameters of the system in Simulink / Matlab: the topology consists of three sub-modules, the inductance connected to the AC port of the H-bridge of the sub-modules is 0.5mH, and the capacitance of the DC side of the sub-modules is 1mF. The front end of the back-to-back converter is connected to an AC power supply, the input voltage is 3000V, and the rear end is connected to a resistive load with a resistance value of 55Ω.

[0071] In the simulation experiment of the embodiment of the present invention, the front-end converter adopts such as Figure 5 , Figure 6 The shown fixed UdcQ control strategy controls the total voltage of the DC side to 4500V, and the DC side voltage of each stage is 1500V. The back-end converter adopts such as Figure 8 The shown constant VF control controls the output voltage to 3300V. Simulation results such as Figure 9 , Figure 10 shown.

[0072] The simulation results show that the topology proposed by the embodime...

specific Embodiment 2

[0074] Set the simulation parameters of the system in Simulink / Matlab: the topology consists of three sub-modules, the inductance connected to the AC port of the H-bridge of the sub-modules is 0.5mH, and the capacitance of the DC side of the sub-modules is 1mF. The front end of the back-to-back converter is connected to AC system 1 with an input voltage of 3000V, and the rear end is connected to AC system 2 with an input voltage of 3000V.

[0075] In the simulation experiment of the embodiment of the present invention, the front-end converter adopts such as Figure 5 , Figure 6 The shown fixed UdcQ control strategy controls the total voltage of the DC side to 4500V, and the DC side voltage of each stage is 1500V. The back-end converter adopts such as Figure 8 As shown in the fixed PQ control, when the simulation starts, control active power P = 50kW, reactive power Q = -50kVar. At 0.5s, control active power P=50kW and reactive power Q=0Var. Simulation results such as F...

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Abstract

The invention discloses a cascaded multilevel converter based on non-isolated back-to-back topology and a control strategy thereof. The cascaded multilevel converter comprises n submodules which are cascaded and have the same structure, wherein each sub-module comprises two H bridges which are connected back to back; the two H bridges share the same direct current side capacitor, and two terminals of an alternating current side port of each H bridge are connected with inductors. According to the novel cascaded multi-level converter based on the non-isolated back-to-back topology provided by the invention, the possibility of direct-current side short circuit of a device in a normal on-off state can be eliminated while a DAB is removed.

Description

technical field [0001] The invention belongs to the technical field of topology and control of distribution network power electronic devices, and in particular relates to a non-isolated back-to-back topology cascaded multilevel converter and its control strategy. Background technique [0002] In the context of the "dual carbon" goal, the proportion of new energy generation such as photovoltaics and wind power is increasing, and new energy is easily restricted by natural conditions, showing the characteristics of uncertainty and instability; in addition, new energy vehicles, smart The access of household loads and other loads also makes the power flow more complicated, which will cause a series of power quality problems. [0003] When a sudden fault occurs in the network, the traditional distribution network mainly provides self-healing strategy support in the form of network reconstruction by installing mechanical switches between adjacent feeders; There are obvious defects...

Claims

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Application Information

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IPC IPC(8): H02M5/458H02M7/483H02M1/088H02J3/36
CPCY02E60/60
Inventor 易皓付康李帅奇赵珂珬崔新雨廖志军
Owner XI AN JIAOTONG UNIV
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