Design and Optimization of Two- stage AC/DC Power Supply Based on Increasing Reliability for Aircraft Power Supply

In this paper, the efficiency and reliability of the two- stage AC/DC power electronic converter has been optimized for use in aircraft systems. The optimization is done using multi- objective genetic algorithm (NSGA- II), in order to minimize the objective function. The objective function variables are efficiency and reliability. Markov model is used to evaluate reliability, in which short circuit and open circuit faults are considered for circuit elements. Also, the failure rate of circuit elements using the equations of the military standard (MIL- HDBK- 217), has been calculated. For optimization, The value of inductances and capacitors, the switching frequency of each stage, the transformer turn ratio and the DC link voltage are determined as the input of the objective function, and then sensitivity analysis is performed to eliminate any parameters that are not sensitive to the objective function.Then NSGA- II algorithm parameters including iteration count, population, mutation and crossover probabilities are defined to calculate circuit parameters and reliability evaluation is done in form of mean time to failure (MTTF) considering efficiency parameter. The results indicate that the converter has improved reliability while maintaining high efficiency.