Robust H_∞ controller design for current mode controlled dc/dc converters

Conclusion

In this paper the design of robust controller for single operating dc/dc converter has been investigated. The controller is designed using H_∞ optimization procedure with Glover-Doyle algorithm. The designed controller achieves stability and performance robustness in the presence of unstructured multiplicative (input) uncertainty. A simple technique is used to reduce the controller order, while maintaining robustness properties. The performance of the closed loop system is evaluated using computer simulation, and the results are compared with previously designed IMC controller and classical PI controller.

The H_∞ -optimal controller achieves acceptable performance for the nominal plant. The results are comparable to the well-tuned classical PI regulator. With a perturbed plant the H_∞ controller is superior to IMC, both regulators maintain stability and acceptable performance, while PI fails to achieve stability.

The superiority of the H_∞ regulator comes from the fact that it has higher degree of freedom than IMC, or PL The main disadvantage of Glover-Doyle algorithm is that it provides high-order controllers. In this case that disadvantage is successfully overcame, and high performance robust regulator is obtained.