“Non-conventional” usually refers to the general control architecture of which multiple feedbacks, feed-forward loops or digital state machines are just a few examples.
In the April issue of Electronics World, in the article named A Novel Numerical Small Signal Modelling Technique for non-PWM, Discontinuous ZVS Buck-Boost Converter, the focus is a particular buck-boost converter topology that requires a modulation technique based on three different inputs: the converter instantaneous input voltage, the instantaneous output voltage and the more traditional control node voltage.
The purpose of this modulation technique is to eliminate the inherent non-linear characteristics of the topology, such that the effective transfer characteristic, as seen from control node to output, can be assumed linear for general control purposes. This obviously puts the burden on the modulator AC modelling and, at the same time, requires a more complex model in order to account for an input-to-output transfer characteristic that might not be negligible, which, in fact, usually is.
To find out more about it, as well as read the other articles we have on the subject of power electronics, order your copy of the April issue of Electronics World or subscribe by going on line at www.electronicsworld.co.uk