Photovoltaic inverter IGBT junction temperature online correction method and system considering aging

Abstract

The invention discloses a photovoltaic inverter IGBT module junction temperature online correction method and system considering an aging process, and belongs to the field of power electronic equipment core device reliability, and the method comprises the steps: building an IGBT model electrothermal coupling model according to a photovoltaic inverter topological structure, illumination radiation intensity and environment temperature; selecting an IGBT collector-emitter electrode on-state voltage drop as an aging parameter, and designing an on-state voltage drop sampling circuit to ensure the measurement precision; aiming at IGBT modules in different aging stages, based on a large-current and small-current injection method, establishing an aging database (test current, an aging threshold value and a calibrated junction temperature value); comparing a junction temperature value output by the electrothermal coupling model with a calibrated junction temperature value, and calibrating an aging process coefficient of an aging correction formula of the electrothermal coupling model; and comparing the IGBT aging monitoring value with the aging threshold value to judge the aging process, and selecting a corresponding aging correction coefficient to ensure the accuracy of junction temperature data.

Description

technical field [0001] The invention belongs to the field of reliability of core components of power electronic equipment, and more specifically relates to an online correction method and system for the junction temperature of a photovoltaic inverter IGBT module taking into account the aging process. Background technique [0002] The photovoltaic power generation industry is one of the fastest-growing emerging industries. As a connection device between distributed power sources and distribution networks, photovoltaic inverters play a key role in the transformation and transmission of electric energy. At present, the most commonly used photovoltaic inverter is a three-phase voltage bridge inverter, whose output phase voltage contains two levels, so it is called a three-phase two-level inverter; insulated gate bipolar transistor ( Insulated Gate Bipolar Transistor (IGBT) is widely used in photovoltaic inverters due to its advantages of fast switching speed, relatively simple d...

AI Technical Summary

Problems solved by technology

Due to the fatigue damage during the working process, the IGBT continues to age, which makes the pre-established electrothermal coupling model no longer suitable for the current IGBT health status

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