An adaptive controller for a boost converter with harmonic reduction

An adaptive controller for the compensation of harmonies in the input voltage is proposed for a Pulse Width Modulated (PWM) boost converter. Following the Lyapunov approach we designed an adaptive law to cope with uncertainties in the disturbance signals. Complexity of the proposed controller is reduced by rotations which transform the adaptive terms into a sum of resonant filters having as input the output voltage error. The resonant filters are tuned at the frequencies of the harmonics under consideration. To facilitate the implementation we have tried to preserve the structure of the proposed controller as close as possible to the conventional controller. The latter is usually composed by a voltage outer loop (basically a Proportional plus Integral (PI) control on the output voltage error) and an inner control loop (basically a Proportional control plus a Feedforward term). Thus, in the proposed controller, the bank of resonant filters appears as a refinement term which is added to the inner control loop. The proposed controller turns out to be robust with respect to parameter uncertainties. Experimental results on a boost converter board, using a poorly regulated voltage source, are presented to assess the performance of our approach.