Reliability Evaluation of DC/DC Converter in Direct Current Collection System of Wind Farm Considering the Influence of Control Strategy

The DC collection system of wind farms can effectively solve the problems of harmonic resonance and reactive power transmission in large-scale wind power AC collection systems, and has broad development prospects. The DC/DC converter is critical equipment in the wind farm DC collection system, and its reliability is related to the entire collection system’s safe and stable operation. The reliability of DC/DC converters is affected by factors such as system operating conditions and control strategies. Based on this, a reliability evaluation model for boost full-bridge isolated (BFBIC) DC/DC converters is proposed from the device level to the submodule level and then to the equipment level, incorporating operating conditions and control strategies into reliability analysis. Firstly, in device-level reliability modeling, the impact of DC/DC converter operating conditions and control strategies on insulated gate bipolar transistor (IGBT) module losses and junction temperature fluctuations are considered. Secondly, fault tree analysis (FTA) is used to establish the reliability model of the BFBIC submodule and DC/DC converter. In the end, we verify the effectiveness of the proposed model through a numerical example, and provide solid data support for analyzing the reliability of the wind farm DC collection system.