A calculation method for igbt junction temperature fluctuation of power electronic converter

Abstract

The invention discloses a calculation method for IGBT junction temperature fluctuation of a power electronic converter, which comprises the following steps: collecting the converter stage variables required for calculating the power loss, performing Fourier decomposition on the output current of the AC side, and obtaining the current After analyzing the IGBT current expression; calculate the switching loss and conduction loss corresponding to the peak current of the AC side respectively, and then obtain the analyzed power loss of the IGBT in the entire fundamental cycle; Combined with the Foster thermal network model, the fundamental cycle is deduced The junction temperature fluctuation expression is derived, and the junction temperature fluctuation expression is derived to obtain the maximum and minimum junction temperature occurrence time points; according to the obtained time points, the maximum and minimum junction temperature values ​​are calculated, the current peak corresponds to the junction temperature value at the moment and the base Component value of the junction temperature fluctuation at the end of the wave cycle. The invention can realize fast calculation of IGBT junction temperature fluctuation, and the calculation result is accurate, comprehensive and reliable.

Description

technical field [0001] The invention belongs to the field of reliability analysis and state monitoring of power electronic converters, and in particular relates to a calculation method for IGBT junction temperature fluctuations of power electronic converters. Background technique [0002] Over the past few decades, while various industries have been seeking higher efficiency and lower cost power electronic converters, reliability issues have emerged and become increasingly important as power electronic Extensive unscheduled maintenance of flow generators is one of the main obstacles to reducing energy costs. At the same time, in order to improve the competitiveness of power electronic converters, how to reduce the design margin while meeting the reliability target has become one of the challenges. IGBT (insulated gatebipolar transistor), as the core component of the power electronic converter, is known as the "CPU" of the power electronic converter, and its reliability is v...

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Problems solved by technology

[0004] In the currently proposed IGBT junction temperature fluctuation calculation method, the calculation of power loss is mostly equivalent to a half-sine curve, which leads to inaccurate loss calculation and further introduces errors into the calculation of junction temperature; in addition, the current reliable The life model of the performance analysis mainly focuses on the junction temperature fluctuation, and only needs to calculate the maximum and minimum junction temperature values. Therefore, the estimation of the junction temperature at other time points leads to a large amount of calculation redundancy in the iterative calculation, which seriously increases the calculation time of the junction temperature. and the amount of computation

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