A multivariable auto-tuning digital controller for switching power converters

This paper presents an online multivariable auto-tuning digital controller for DC-DC switching power converters. In the proposed scheme, all the variables/parameters (i.e. gain, zero(s) and pole(s)) of a digital PID compensator are auto-tuned simultaneously during system operation in order to achieve an optimized compensator that results in improved dynamic performance for a given power converter design. The proposed multivariable auto-tuning scheme is based on observing the time-domain characteristics of the compensated error signal, namely the output of the compensator, and it does not require the accurate knowledge of the power stage parameters and/or the measurement of the control loop frequency response. Experimental results are presented in order to illustrate and verify the multivariable auto-tuning scheme.