This paper presents fast test protocols for ageing IGBT modules in power cycling conditions, and a monitoring device that tracks the on-state voltage V-CE and junction temperature T-j IGBTs during ageing test operations. This device is implemented in an ageing test bench described in previous papers, but which has since been modified to perform fast power cycling tests.The fast test protocols described here use the thermal variations imposed on IGBT modules by a test bench operating under Pulse Width Modulation conditions. This test bench reaches the maximal values of power cycling frequencies attainable with a given module packaging in order to optimize test duration.The measurement device monitors V-CE throughout the ageing test that is needed to detect possible degradations of wire bonds and/or emitter metallization. This requires identifying small V-CE variations (a few dozen mV). In addition, the thermal swing amplitude of power cycling must be adjusted to achieve a given ageing protocol. This requires measuring junction temperature evolution on a power cycle, which is carried out by means of V-CE measurement at a low current level (100 mA).Experimental results demonstrate the flexibility of this test bench with respect to various power cycling conditions, as well as the feasibility of the proposed on-line monitoring methods. (C) 2014 Elsevier Ltd. All rights reserved.

This paper describes a part of a larger supervision system able to monitor the on-state voltage VCE and the junction temperature TJ of IGBT in operation. That system is associated to an ageing test bench stressing IGBT modules by power cycling. All along the ageing test, it is necessary to supervise VCE, always measured in the same conditions of junction temperature and collector current, in order to detect possible degradations of wire bonds and/or emitter metallization. In addition, the thermal swing amplitude of the power cycling must be adjusted to realize a given ageing protocol. That requires measuring the junction temperature evolution on a power cycle to choose the initial electrical conditions providing the wished temperature swing and then, to regularly verify the stability of this thermal stress during the ageing test. The temperature measurement needed for both monitoring is carried out by means of VCE measurement at low current level (100mA), that intrinsic on-stage voltage being a well-known thermo sensitive parameter. The first section describes briefly the ageing test bench, that places the power IGBT modules in operating conditions close to those of real world (PWM operations), and presents the thermal stress protocol applied to the devices, the aim being to define the context in which the measurements have to be made. The second section presents, on the one hand, the principle of an automated measurement of VCE(100A-125°C), made in steady-state, to detect a possible degradation of the top part of IGBT dies, on the other hand, the dynamic measurement of the junction temperature in operation, i.e. in power cycling conditions generated by the PWM modulation. In both cases, experimental results are shown that demonstrate the feasibility and the good accuracy of these monitoring methods.

This paper describes a part of a larger supervision system able to monitor the on-state voltage V CE and the junction temperature T J of IGBT in operation. That system is associated to an ageing test bench stressing IGBT modules by power cycling. All along the ageing test, it is necessary to supervise V CE , always measured in the same conditions of junction temperature and collector current, in order to detect possible degradations of wire bonds and/or emitter metallization. In addition, the thermal swing amplitude of the power cycling must be adjusted to realize a given ageing protocol. That requires measuring the junction temperature evolution on a power cycle to choose the initial electrical conditions providing the wished temperature swing and then, to regularly verify the stability of this thermal stress during the ageing test. The temperature measurement needed for both monitoring is carried out by means of V CE measurement at low current level (100mA), that intrinsic on-stage voltage being a well-known thermo sensitive parameter. The first section describes briefly the ageing test bench, that places the power IGBT modules in operating conditions close to those of real world (PWM operations), and presents the thermal stress protocol applied to the devices, the aim being to define the context in which the measurements have to be made. The second section presents, on the one hand, the principle of an automated measurement of V CE (100A-125°C), made in steady-state, to detect a possible degradation of the top part of IGBT dies, on the other hand, the dynamic measurement of the junction temperature in operation, i.e. in power cycling conditions generated by the PWM modulation. In both cases, experimental results are shown that demonstrate the feasibility and the good accuracy of these monitoring methods.

The supervision of semiconductor power devices in operation demonstrates an obvious interest to improve the operating safety of electronic power converters used in critical applications. Unfortunately, this is a significant challenge due to the variability of stress conditions on the one hand and to the difficulty to implement accurate measurement systems in power stages on the other. Using V CE measurement as a real-time supervision method is evaluated here by using aging test results obtained on insulated gate bipolar transistor (IGBT) modules stressed by power cycling. These results are related to the aging of bond wires and metallization, on the top part of the module. Results were obtained in original test benches whose characteristics are overviewed briefly in the first part of this paper, along with a description of test conditions. The second part presents selected results extracted from a larger work and focusing on the V CE evolution with respect to degradations of the module's top part. Their analysis highlights the potential of V CE measurement. The last part proposes the principle of a specific system able to achieve real-time V CE supervision in the test benches in operation.