Power cycling results for different control strategies

Power cycling is an important method to characterize the lifetime of power semiconductor modules. Application engineers use lifetime curves published by manufacturers to verify that their system design meets the required reliability. An important condition for the lifetime of a module under repeated temperature swings is the control strategy applied during the test. Power cycling tests with identical start condition but different control strategies have been performed, which have been conducted on specially assembled test equipment with ultimate control of all test parameters. The results show, that different control strategies deliver lifetime results that vary by a factor of 3.