Performance comparison between H∞ and PID control strategies applied to Boost power converters

In this paper, a comparison between a current-programmed PID controller and a mixed - sensitivity H∞ controller applied to a Boost power converter will be discussed. The paper carries out the design of the power converter, according to its power and voltage levels. Then, is discussed the design of both control strategies. For the H∞ controller synthesis is discussed the selection of the weight functions and the implication in the close loop system. For the PID controller, is discussed the PID pole-zero placement that secures the close loop system behavior, according to bandwidth and offset requirements. It was found that although the H∞ controller has some problems with the disturbance rejection from variations of the power source and high increments in the load, the amount of energy required by the controller and the dynamical performance of the output voltage against load or power source variation shows a better performance compared with the cascade PID controller, which uses a current sensor for the strategy that can be avoided with a proper H∞ controller or other loop-shaping based controller design.