Worst-Case Tolerance Analysis for a Power Electronic System by a Modified Relay-Search Genetic Algorithm

Abstract

It is necessary to consider variations of circuit element values for power electronic converter design to satisfy a given specification for a frequency characteristic or a dynamic transient response because the variations of element values generate those of the designed characteristic. Therefore element values and their variation ranges should be designed to give a satisfactory characteristic within an allowable specification range or a tolerance. This analysis is so-called tolerance or worst-case analysis. The analysis is a sort of nonlinear minimum and maximum (min/max) problem with respect to circuit or system parameters. However it is not possible to solve a transient type problem generally. Hence, the problem is converted to a simpler and easier one with various techniques. This paper proposes a new Genetic Algorithm (GA) method, or a sort of a modified relay-search-GA, which is suitable for practical and efficient tolerance analysis by considering diversity of solutions. Output voltage analysis examples of three types of converters for element parameter variations are investigated for effectiveness of the proposed method.