Wuhan University

Chuankun Wang

Yigang He

Lie Li

Chenyuan Wang

Weiwei Zhang

A reliability evaluation method and system for a microgrid inverter IGBT based on segmented long short-term memory (LSTM) is disclosed, including steps as follows. An electrothermal coupling model is constructed to obtain real-time junction temperature data. The original LSTM algorithm is improved to obtain a segmented LSTM prediction network for the aging characteristics of the IGBT. The monitoring value of the IGBT aging parameter is used to perform segmented LSTM prediction to obtain the predicted aging process, and the threshold values of different aging stages are categorized. An aging correction is performed on the aging parameter of the electrothermal coupling model to ensure the accuracy of the junction temperature data. Rainflow-counting algorithm is used to calculate real-time thermal stress load distribution of the IGBT. The fatigue damage theory and the Lesit life prediction model are combined to calculate the real-time cumulative damage and predicted life of the IGBT.

Reliability evaluation method and system of microgrid inverter IGBT based on segmented LSTM

The invention discloses a method and a system for correction of the junction temperatures of an IGBT module in a photovoltaic inverter. The method includes: constructing an electrothermal coupling model of an IGBT model based on a photovoltaic inverter topology, a light radiation intensity, and an ambient temperature; selecting an IGBT collector-emitter on-state voltage drop as an aging parameter and designing an on-state voltage drop sampling circuit to ensure measurement accuracy; constructing an aging database for IGBT modules in different aging stages based on large current and small current injection methods; comparing a junction temperature value output by the electrothermal coupling model with the calibrated junction temperature value and calibrating an aging process coefficient of an electrothermal coupling model correction formula; comparing an IGBT aging monitoring value with the aging threshold to determine the aging process and selecting a corresponding aging process coefficient to ensure accuracy of junction temperature data.

Method and system for online correction of junction temperatures of IGBT in photovoltaic inverter considering aging process

The disclosure discloses a multi-time-scale reliability evaluation method of a wind power IGBT considering fatigue damage and a system thereof. Lifetime information of a power device is comprehensively extracted by using multiple time scales. An electro-thermal coupling model of an IGBT module is established to obtain a junction temperature data. A steady-state junction temperature database of the IGBT in different aging states is established. Based on a SCADA monitoring data, the junction temperature data is outputted in real-time through the electro-thermal coupling model and a real-time thermal stress cycle number is calculated in a short-term time-scale profile, and a wind speed probability distribution curve is obtained in a long-term time-scale profile. A maximum thermal stress cycle number that the IGBT can withstand in different aging stages is obtained in advance and a cumulative damage degree and an estimated lifetime of the IGBT of the wind power converter are calculated.

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Hubei, China

Chuankun Wang