A comparative study on nonlinear dynamics: between peak current mode, peak V2 and enhanced V2 modulated buck converter

The studies on Nonlinear Phenomena have been carried out in buck converter controlled by three different types of modulation technique—Peak current, Peak V² and Enhanced V². These three modulation methods are rippled based control methods as inductor current ripple is used in Peak current modulation (PCM) method and output ripple voltage used in both Peak V² and Enhanced V² modulation methods and due to that all three modulation methods provide fast dynamic response. Here three modulation techniques have been explained in details and simulation results have been provided. For designing the modulators—we consider two loops i.e. inner loop or fast feedback path (FFBP) and outer loop or slow feedback path (SFBP). The outer loop of all these three modulation methods contains same information, the difference between reference voltage and output voltage. Mathematical model has been developed with the help of state space equation in continuous conduction mode (CCM). Bifurcation diagrams are obtained with load resistance, input voltage and reference voltage as bifurcation parameter. To validate the bifurcation pattern, time plot and phase plane trajectory at each transition have been shown for these three types of modulated system. A comparative study has been made. Experiments are conducted on an enhanced V² modulated buck converter to validate the nature of the nonlinearities. To check the dependency of the system on ESR value, parameter space plots are developed and compared for all these three types of control technique.