Research on avalanche tolerance test method for power devices based on avalanche energy equivalence

Abstract A general avalanche tester that utilizes an unclamped inductive switching (UIS) test is essential for measuring the maximum energy that a power device can withstand before failure. This procedure is critical for evaluating the reliability and robustness of power devices. Avalanche testers typically require high-precision hollow inductors with broad adjustable ranges and fine increments to accommodate the varying test conditions of different devices. However, this often results in large, heavy, and expensive inductor modules. In this study, we propose and experimentally demonstrate a novel method for testing avalanche tolerance based on avalanche energy equivalence. This method employs the magnetic core inductance as an alternative to the traditionally used bulky air-core inductance in avalanche testers, producing results comparable to those obtained from conventional UIS tests. To verify the equivalence of the avalanche energy, we designed a UIS experimental platform that includes a 1.3 mH magnetic core inductor connected in series with an adjustable air-core inductor. This configuration enables the evaluation of the maximum avalanche current consistency and degree of core inductor attenuation during the UIS test for two commercial P-channel and N-channel power MOSFET devices. The experimental results indicate that the difference between the avalanche energy and maximum avalanche current in the UIS test under both inductor conditions is approximately 1 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">%</mml:mi> </mml:mrow> </mml:math> . Consequently, the magnetic core inductor can replace the air-core inductor. The method proposed in this study offers a promising direction for optimizing avalanche testers to meet the demands of modern devices for miniaturization and high efficiency, thereby reducing material consumption, production costs, and transportation expenses. This enhances product market competitiveness and holds practical value in engineering applications.