Modeling and control of multiphase DC-DC converters with linkages to hybrid control

Feedback control design of dc-dc converters requires a dynamic model of the converter system. Linearized average (small signal) models permit the use of linear feedback design methods. Small signal sensorless current mode (SCM) models for dc-dc converters are developed in this dissertation. These small signal models show: (i) how to select the SCM stabilizing ramp-slope for proper disturbance rejection performance; (ii) how to design effective feedback control for SCM systems.; The small signal models reveal three properties of SCM-controlled dc-dc converters. All SCM systems are capable of: (i) perfect steady-state step line disturbance rejection; (ii) steady-state step load disturbance rejection; (iii) steady-state step reference tracking. These step response results are accurate within deviations dictated by parasitic resistances of the converter. Setting the ramp-slope for SCM buck converters to half of the SCM control law off-slope, makes the line disturbance to output response identically zero (null).; Multiphase voltage regulator modules (VRMs) are multiple dc-dc converters (phases) in parallel-input parallel-output configuration. This dissertation investigates the dynamic effects of interleaving on SCM and PCM controlled multiphase VRMs. Since SCM offers good dynamic reference tracking, it is useful for meeting tight dynamic microprocessor regulation requirements. Reduced order single-phase equivalent models for PCM and SCM-based multiphase VRMs for use in feedback control designs are derived and validated by experimental systems. The effective switching period of the single-phase equivalent models is shown to be the switching period of a single phase.; Despite the small signal null audio susceptibility condition, large signal null audio susceptibility is not achieved by SCM or PCM. Definitions of optimal large signal line disturbance rejection criteria for buck converters are based on timing and on the number of switching transitions needed to recover to steady state. Examples of switching patterns that meet these criteria are shown.; Deadbeat controllability is defined for dc-dc converters as the existence of switching actions that can drive the state between two valid limit cycles in a finite amount of time, with a finite number of switch transitions. Sufficient but conservative algebraic conditions for deadbeat controllability of piecewise linear hybrid systems with finite state-vector dimension are presented.