Issues in boundary control [of power convertors]

State plane analysis is used to study large-signal properties and control strategies for DC-DC power converters. A general load line is defined and interpreted. The concept of a switching boundary is convenient for generalizing hysteretic controls. Boundaries are classified according to their local dynamics. Requirements for large-signal stability are established. It is shown that stable boundary controllers always require frequency limits or timing constraints to avoid chattering. Limit cycles occur under certain conditions when discontinuous mode adds a second boundary.