A method of controlling the stability of a power converter in a closed-loop control system. The method includes inputting a variable to be controlled such as an output voltage of the power converter to a compensator or mathematical function for processing; determining, using the compensator, an error signal representative of a difference between the output voltage and a reference voltage; evaluating an energy content in a short-time Fourier transform spectrogram of the error signal from the compensator and/or evaluating the sinusoidality shape of the error signal; updating a transfer function of the compensator and other system parameters in accordance with the energy content or sinusoidality.