Fault-Tree-Based Failure-Rate Analysis for Clamped-Double Submodule Employing dc-Short Current Protecting Function
- PDF / 1,930,000 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 81 Downloads / 148 Views
ORIGINAL ARTICLE
Fault‑Tree‑Based Failure‑Rate Analysis for Clamped‑Double Submodule Employing dc‑Short Current Protecting Function Feel‑soon Kang1 · Sung‑Geun Song2 Received: 10 May 2020 / Revised: 8 September 2020 / Accepted: 13 October 2020 © The Korean Institute of Electrical Engineers 2020
Abstract Clamped-double submodule has dc short current protecting function, which can improve safety and stability of HVDC system. However, it needs additional IGBT, diode, and capacitor compared to the conventional half-bridge and full-bridge submodules. Generally, the failure-rate increases in proportion to the number of circuit components. Complex operation of the submodule may increase the failure-rate, so accurate reliability analysis is required to apply CDSM in practical HVDC system. Fault-tree-based reliability analysis is performed to take into account the operational characteristics of CDSM. FTA is possible to analyze the failure-rate more accurately than the prior PCA that considers only the type of parts, the number of parts, and the connection status. By comparing the failure-rate of a CDSM with typical HBSM and FBSM, and analyzing the failure-rate according to the voltage margin of the parts, it provides guidelines for submodule selection under various conditions. Keywords Clamped-double submodule (CDSM) · Full-bridge submodule (FBSM) · Half-bridge submodule (HBSM) · Fault-tree analysis (FTA) · Mean time between failures (MTBF) · Part count failure analysis (PCA)
1 Introduction The basic role of the HVDC submodule is power conversion and power supply, so it is important to select a highly reliable circuit topology [1–5]. Half-bridge and full-bridge submodules are generally used in HVDC. Recently, various circuit structures have been introduced to achieve specific purposes such as dc short current protection, voltage or current stress reduction, efficiency improvement, and cost reduction [4, 6–9]. In order to apply these submodules to an actual HVDC system, it is important to predict reliability through more accurate failure-rate analysis. Reliability refers to the probability that a system faithfully performs a specified function during a target period under specified conditions. Failure-rate, one of the representative indicators * Feel‑soon Kang [email protected] Sung‑Geun Song [email protected] 1
Department of Electronics and Control Engineering, Hanbat National University, Daejeon, Korea
Energy Conversion Research Centre, Korea Electronics Technology Institute, Gwangju, Korea
2
of reliability, is the number of failures of individual parts and devices per unit time and is expressed as the inverse of mean time between failure (MTBF) or mean time to failure (MTTF), which is the standard for life-cycle [10, 11]. Reliability prediction models suitable for large-capacity high power conversion systems such as HVDC are part count model, combined model, Markov model, and binominal distribution model [12–17]. Part count model is a prediction technique based on the assumption that the failure-rate o
Data Loading...
