Adaptive model following control of switching regulators

Abstract

Parametric uncertainty in switching power supplies (SPS) and their loads can result in unstable operation or failure to meet performance specifications. Adaptive model following control (AMFC) is proposed to assure robust operation of SPS. This control approach results in stable operation and desired transient response of switching converters, while mitigating the effects of parameter uncertainty and drift. An adaptation mechanism is designed utilizing the hyperstability and positivity principles. AMFC of buck, boost and buck-boost converters operating in the continuous mode is considered: an analog hardware implementation of AMFC of a buck converter is demonstrated and compared to simulation results. The laboratory data validates the simulation model. The data demonstrates that AMFC results in stable operation with nearly invariant open-loop frequency response with more than a 2:1 variation in power converter component values. It is shown that with AMFC audiosusceptibility is unchanged, whereas, output impedance is lowered, compared to conventional voltage mode control.