Personnel

FICs - Prof. Wing-Hung Ki and Prof. Philip K. T. Mok

Description

A switch mode power converter, or switching converter for short, is basically a non-linear sampled-data system. Analysis of non-linear systemsfalls into two major categories: large signal analysis and small signalanalysis. We will focus on the small signal analysis, since the resultsthus obtained will be useful for design engineers trained to interpretBode plots of loop gains. Technique of state-space averaging will be usedin the averaging process. Then the signal flow graph (SFG) is generatedfor the converter from the perturbed state-space averaged equations, andthe characteristic polynomial of the system is computed. By grouping termsassociating with the gain of the error amplifier, a unique system loopgain for either a voltage-programming or current-programming converterwith either trailing-edge or leading-edge modulation is computed. Thismethod is demonstrated to be applicable to all second order PWM (pulsewidthmodulated, i.e., fixed frequency) switching converters operating in thecontinuous conduction mode (CCM). We proposed to apply the same strategyto analyze DCM (discontinuous conduction mode) converters, and finallyto PFM (pulsed frequency modulated, i.e., variable frequency) converters.All converters are to be implemented with integrated circuit controllers,and measurements will be performed to confirm the analyses.

Source: RGC | ITF