Electrolytic Capacitors (E-Cap) as the passive energy buffer in single-phase converter are often assumed to be the reliability bottleneck of power electronic system. Various Active Power Decoupling (APD) methods have been proposed intending to improve the reliability of the DC-link E-Caps qualitatively, making great effort to diverting the instantaneous pulsation power into extra reliable storage components. However, it is still an open question, which method is the most cost-effective one for a specific application with a given lifetime requirement. In this paper, two of the representative APD methods and the classical passive DC-link design method are evaluated from the reliability and cost perspective. The reliability-oriented design procedure is applied to size the chip area of active switching devices and the passive components to fulfill a specific lifetime target. Component cost models are applied to obtain the overall cost of each DC-link design methods. The cost comparisons are performed with a lifetime target of 10 years and 35 years. It reveals that different conclusions can be drawn with different lifetime targets in terms of cost-effectiveness.
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