Novel power equalization modulation method suitable for cascaded H-bridge multi-level inverter

A multi-level inverter, inverter technology, applied in output power conversion devices, AC power input conversion to DC power output, electrical components and other directions, can solve problems such as shortening power equalization time

Pending Publication Date: 2021-09-14
ANHUI UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The present invention is aimed at cascaded H-bridge multi-level inverters, and proposes a new power modulation method, which solves the contradiction between cascaded output power balance and output line voltage quality, and at the same time shortens the power balance time

Method used

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  • Novel power equalization modulation method suitable for cascaded H-bridge multi-level inverter
  • Novel power equalization modulation method suitable for cascaded H-bridge multi-level inverter
  • Novel power equalization modulation method suitable for cascaded H-bridge multi-level inverter

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Embodiment Construction

[0025] figure 1 The circuit topology of the CHB inverter is given. This topology includes n H-bridge units. The DC side of each H-bridge unit is a power supply, and the power supply voltage is equal, that is, U d1 =U d2 =…=U dn =E. In addition, the power switching devices of the H-bridge unit use full-control devices such as IGBT and GTO, and the specific device selection is based on comprehensive consideration of factors such as voltage level and switching frequency.

[0026] Each unit of this topology can output three levels of -1, 0 and 1, then the output voltage of each unit can be expressed as

[0027] u oi =xU di (1)

[0028] where u oi is the output voltage of the i-th H-bridge unit, i=1,2,...n, x is the output level of the H-bridge unit, x=-1,0,1, U di is the DC side power supply voltage of the cascaded unit.

[0029] The output voltage u of the topology inverter can be obtained from formula (1) o for

[0030]

[0031] For the convenience of analysis, th...

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Abstract

The invention relates to a balanced modulation method suitable for a cascaded H-bridge multi-level inverter, and belongs to the technical field of PWM (Pulse Width Modulation) of a multi-level converter. According to the method, based on a double triangular carrier period, a triangular carrier is periodically circulated between different carrier layers, and compared with a sinusoidal modulation wave, an optimized pulse signal is generated. According to the method, the power balance control of each cascade unit can be realized, the direct current side power supply discharge is kept consistent, and the quality of the output voltage of the inverter is further improved; the time required for power equalization can be reduced; and meanwhile, the optimal line voltage harmonic elimination performance can also be realized. In addition, the method can be expanded to n cascade units, so that the practicability of the inverter is improved.

Description

technical field [0001] The invention belongs to the technical field of PWM of multilevel converters, and in particular relates to a novel power balance modulation method suitable for cascaded H-bridge multilevel inverters. Background technique [0002] In recent years, multi-level inverters have gradually replaced traditional two-level inverters in the high-voltage and high-power field due to their small voltage stress, low electromagnetic interference, and no voltage equalization problems in series with switching tubes, and have become a research hotspot. Common multilevel inverter topologies include flying capacitor type, diode clamp type, and cascaded H-bridge (Cascaded H-bridge, CHB) type, among which CHB type inverter is simple in structure, easy to expand, easy to Modularization and other advantages have been widely used in static var compensators, power active filters, power electronic transformers and other occasions. [0003] As one of the key technologies in multi...

Claims

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Application Information

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IPC IPC(8): H02M7/5387H02M1/088H02M1/32H02M1/12
CPCH02M7/53871H02M1/088H02M1/32H02M1/12
Inventor 顾军宋飞许青春李平张维国张明杜治斌
Owner ANHUI UNIV OF SCI & TECH
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