The Reliability Objective and Integration
It is well established in military electronics that the more parts are in a system, the more likely it is to fail. As we shall see, power electronic circuits tend to have few parts, especially in the main energy flow paths. The necessary operations must be carried out through shrewd use of those parts. Often, this means that sophisticated control strategies are applied to seemingly simple conversion circuits
One way to avoid the reliability-complexity tradeoff is to used highly integrated components. A high-end microprocessor, for example, contains more than a million parts. Since all interconnections and signals flow within a single chip, the reliability is nearly that of a single part. An important parallel trend in power electronic devices is the integrated module. Manufacturers seek ways to package several switching devices, their interconnections,and protection components as a unit. Control circuits for converters are also integrated as much as possible to keep reliability high.