Optimized Design of Grid-Side Converter in PMSG with Improved Turbine-Level Reliability

With the high penetration of Permanent Magnet Synchronous Generator (PMSG) based wind farm integrated to power grid, the reliability of the PMSG system becomes more and more important. The thermal dynamics of grid-side converter (GSC) and machine-side converter (MSC) are inseparably linked to the reliability and the cost of the full power electronic converter. Using a mission profile with the 1-hour sample rate and based on the circuit model, loss model, and thermal model of the active switches, the percentile lifetime can be predicted, as well as the Weibull function based time-to-failure distribution of the single component. In a traditional 2 MW wind turbine system, based on the reliability block diagram, the unreliabilities of modules, converters, and the turbine are calculated. It can be seen that the MSC determines the turbine-level reliability. By applying an optimized structure of the GSC, the lifetime distribution between the machine and grid side power converters becomes more balanced. Meanwhile, the optimized structure is still able to fulfill 20-year desired lifetime.