Online monitoring method for DC-link capacitor of three-phase system

A DC bus capacitor and three-phase technology, applied in the electric power field, can solve the problems of occupying equipment volume, not being suitable for industrial applications, and destroying the main power circuit.

Active Publication Date: 2016-06-29
CHONGQING UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In recent years, various capacitance online monitoring technologies have emerged, but there are usually capacitive current sensors, which will destroy the main power circu

Method used

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  • Online monitoring method for DC-link capacitor of three-phase system
  • Online monitoring method for DC-link capacitor of three-phase system
  • Online monitoring method for DC-link capacitor of three-phase system

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Embodiment Construction

[0032] The present invention will be further described below in conjunction with accompanying drawing and embodiment: figure 1 It is a schematic diagram of the principle of the present invention, figure 2 is a schematic diagram of the capacitive current reconstruction process of the present invention, image 3 is a schematic diagram of the case simulation system of the present invention, Figure 4 is a schematic diagram of the DC bus voltage drop curve of the present invention, Figure 5 It is a schematic diagram of the simulation waveform of the DC bus voltage and current of the present invention, Figure 6 It is a schematic diagram of three-phase switch states and three-phase current simulation waveforms of the present invention.

[0033] Such as figure 1 As shown, the online monitoring method of the three-phase system DC bus capacitance in this embodiment includes

[0034] a. Control the three-phase system to stop working, and keep the inverter bridge in the working s...

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Abstract

The invention provides an online monitoring method for a DC-link capacitor of a three-phase system. The method comprises that voltage of the DC-link capacitor is collected, and a voltage drop curve of the DC-link capacitor is obtained; three-phase output current is collected, and capacitive current is reconstructed according to the three-phase output current; and the capacitance (C) and equivalent serial resistance (ESR) of the DC-link capacitor are obtained according to the voltage drop curve and the capacitive current of the DC-link capacitor. The voltage drop curve and the three-phase output current of the DC-link capacitor as well as control signals of a semiconductor switch are monitored in the process that power equipment as a three-phase frequency converter is switched off, so that the C and ESR of the DC-link capacitor are calculated accurately, and non-invasive online monitoring for the DC-link capacitor of the AC/DC/AC system is realized. The method can be applied to online monitoring for an aluminum electrolytic capacitor, other capacitors as a film capacitor as well as other three-phase systems including a wind power converter, a photovoltaic AC/DC/AC system and a three-phase aviation power system.

Description

technical field [0001] The invention relates to the field of electric power, in particular to an on-line monitoring method for a three-phase system DC bus capacitance. Background technique [0002] With the development of society and the advancement of science and technology, power electronics technology is playing an increasingly important role in modern industries, especially in modern industries such as wind power generation, solar power generation, electric vehicles, and electronic lighting. Further applications and developments. With the continuous expansion of the application range of power electronic technology, the use of power electronic devices is also increasing year by year. However, power electronic devices will fail due to long-term work aging, resulting in systematic failures and huge economic losses. Emphasis on the reliability of power electronic devices. Among power electronic devices, electrolytic capacitors, IGBTs, diodes, MOS tubes and other devices ha...

Claims

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Application Information

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IPC IPC(8): G01R27/26
CPCG01R27/2605
Inventor 周雒维吴宇孙鹏菊吴杭举杨友耕杜雄谢广成刘黎辉
Owner CHONGQING UNIV
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