Design of a robust PI controller for a dual active bridge converter

This paper addresses the voltage regulation of dual active bridge converters based on robust PI controllers. The plant model presents a dependence on an uncertain parameter, which defines the operation condition, motivating the design of robust PI controllers for this application. Linear matrix inequalities are then used to synthesize control gains which ensure the closed-loop pole location inside a sector in the left-hand of the complex plane for the entire set of uncertainties. Comparisons with a PI controller designed only for a nominal condition indicate advantages of the robust PI in terms of step responses. It is shown that other criteria can also be associated with the proposed design conditions to ensure the achievement of frequency domain specifications.