Power electronics reliability and stochastic performances of innovative ac traction drives: a comparative analysis

An on-board line transformer is adopted on actual ac locomotives to reduce line voltages to levels suitable to power electronic components and to guarantee galvanic insulation. Unfortunately, such a transformer is heavy, expensive and represents one of the main reasons why traction vehicles often exceed the targets for weight and dimensions. Aim of this paper is to evaluate, trough a comparison with a conventional architecture, the effectiveness deriving from the adoption of a non-conventional conversion system, which allows the use of transformers of greatly reduced size. Playing power electronics a fundamental role in both solutions, a detailed analysis based on the Monte Carlo procedure has been carried out to compare the stochastic performances of the loco electrical drive systems under analysis, as a function of the reliability characteristics of their basic components.