Abstract: The operation principle of zero-current-switching quasi-resonant boost converter is presented and its nonlinear model is built up using simple analytical techniques based on topological circuit. The relationship between voltage conversion ratio and switching frequency is obtained and analyzed under different load. Simulation results show that the full-wave pulse frequency modulation should be adopted in order to get the required output voltage under different load and different input voltage. The output voltage under step input is also simulated and analyzed. The model is easily implemented by MATLAB, simulation results have shown its accuracy for large-signal transient response.

Key words: quasi-resonant converters, zero-current-switching, nonlinear model, voltage conversion ratio