Dual-loop geometric-based control of boost converters

Voltage mode and dual-loop current-mode linear schemes are widely used for controlling boost converters due to their simple implementation and fixed frequency PWM operation. Nevertheless, the dynamic response of the voltage loop is usually limited by the characteristic non-minimum phase behaviour of the boost topology. On the other hand, excellent dynamic performances can be achieved with boundary controllers in which the demands placed on processors and sensors are greatly increased. A novel trajectory-based dual-loop control scheme is introduced in this work by combining linear techniques with state-plane analysis. Geometric trajectories are employed to define the outer voltage loop, allowing to achieve fast and reliable dynamic response. The well-known issues caused by the right-half plane zero are solved by defining the outer voltage loop control using simple geometric equations. The proposed trajectory-based voltage loop tightly controls the time-domain evolution of the state variables, providing a reliable transient response by following a desired geometrical path to reach the desired steady state operating point. Straight line and circular trajectories are implemented resulting in an outstanding, well defined, and reliable transient behaviour. Experimental results of dual-loop geometric-based controlled 100W platform validate the proposed control concept and highlight the strong contribution to the theoretical and applied fields made by this innovative controller.