System-Level Reliability-Oriented Power Sharing Strategy for DC Power Systems

Abstract

Power converters are one of the failure sources in modern power systems, and hence driver of maintenance and downtime costs, which should be reduced by reliable design, control and operation of converters. This paper proposes a power sharing control strategy for evenly distributing the thermal stresses among dc converters in dc microgrids, and consequently enhancing the overall system reliability. The aim of this paper is to extend the aging process of failure prone converters by adjusting their loadings. The proposed approach employs the prior experienced thermal damages on the converter's fragile components in order to adjust its contribution on demand supply. According to the proposed strategy, the higher the thermal stress on a converter is, the lower the power it will supply. As a result, the overall system reliability will be improved. A numerical case study on a dc microgrid is presented to illustrate the effectiveness of the proposed power sharing strategy. Moreover, experimental tests are provided to demonstrate the applicability of the reliability-oriented power sharing method.

Failure Mode, Effects and Criticality Analysis (FMECA) in Power Electronic based Power Systems

“…In this paper, the first and second order outage events are considered since the higher order outages probability is negligible. The probability of outage events is calculated using (4). Afterwards, the effect of outages on the PNP is determined.…”

“…These efforts have been carried out in the component, converter and operation levels for a single or multiple converter [4] from a wear-out failure point of view, which is suitable for the design and manufacturing of converters.…”

“…The aforementioned issues are intensifying the significance of reliability modeling in a modern PEPS, specially its main and failure prone components such as power converters. The converter reliability modeling can be carried out at three hierarchal levels including device, converter and system levels [4]. Device level modeling requires to consider the very fast dynamics of operation such as semiconductor switching effects [14].…”

System-Level Design for Reliability and Maintenance Scheduling in Modern Power Electronic-Based Power Systems

“…The MBSE approaches analyze, assess and enhance the converter reliability taking into account physics of failure mechanisms of its components. The state-of-the-art MBSE approaches can be hierarchically classified into three categories including component-, converter-, and system-level [22]. The component-level efforts are devoted to analyzing, modeling and enhancement of the failure modes and mechanisms in converter components such as power electronic switches and capacitors.…”

“…The converter reliability is predicted based on a stressstrength analysis comparing applied stresses induced by a mission profile to its components lifetime [23]. Therefore, the converter reliability depends on its components lifetime, climate and operating conditions, converter topology [24]- [26], control algorithm [22], [27]- [31], and cooling system etc. Hence, design for reliability considering these factors can guarantee a desired long-term performance of converters.…”