Hybrid discretization in power converters´ digital controller design

Digital compensator design is an important and essential step to achieve stable power converter with good steady-state and dynamic performance. Generally there are two digital controller design approaches: The digital redesign approach and the direct design approach. In this paper, hybrid discretization (s-to-z transformation) approach is applied to power converters digital controllers/compensators to achieve better redesigned controller. This is because of the fact that two or more transformation methods with opposite warping effects can be hybridized when discretizing the analog transfer function to reduce the total warping effect. Hybrid discretization can be implemented by different ways, of which three were discussed in this paper. Theoretical, design and simulation results show that better controller/compensator design results, which are closer to the analog case, can be achieved using hybrid discretization technique in the digital redesign approach rather than using single transformation method