Implementing Robust Design Principles in Aircraft Power Systems Design

*Power system reliability is critical to the performance of modern aircraft. Reliability issues must be considered from the beginning of the power system design process. Addressing these issues can complicate a design flow. To manage this complexity, design teams must use an organized approach based on proven design principles. A Robust Design methodology provides this organized approach. This paper investigates the Robust Design process as it pertains to system design. General Robust Design principles are introduced and related to the development of aircraft power systems. Design tasks are outlined as they apply to the Robust Design process. These tasks are then related to the capabilities that design tools must have to help design teams improve system reliability. A basic 3-phase, 230VACto-28VDC converter is analyzed using the Saber® simulator from Synopsys, Inc. The analysis follows the steps of a Robust Design-based flow and includes a nominal analysis to establish a performance baseline for the system, a sensitivity analysis to investigate which design parameters have the most affect on system performance, a parametric analysis to evaluate system performance while key design parameters are swept through selected values, a statistical analysis to analyze the system’s performance as parameter values are allowed to randomly change within their tolerance range, a stress analysis to evaluate stresses placed on system components, and a failure modes analysis to examine system performance as individual components fail. Establishing simulation techniques for implementing a Robust Design flow is the primary focus of this paper. Understanding detailed converter design is left as an exercise for the reader.