Analysis and Design of Single Ended Resonant Reset Forward Converter

Abstract

This project works presents the complete analysis of different working modes, circuit design, small signal modelling, open loop and closed loop analysis of resonant reset forward converter. In conventional forward converter design tertiary winding has been used for core flux resetting but we are using resonant reset technique for flux resetting of forward converter operating at 100 kHz frequency. Leakage inductances and magnetizing inductance of a transformer forms an oscillating circuit with switch and diodes distributed capacitances. Analysis of resonant reset technique is complex but its implementation is easy. Voltage Mode Control technique is used for regulating the converter output. Optocoupler is used for providing isolation in the feedback path which reduces the circuit complexity. Though Optocoupler degrades the phase margin of the system hence complete modelling of Optocoupler is explained in this project to remove its disadvantage. After voltage mode control the Current Mode Control of resonant reset forward converter is explained to point out the difference between Voltage Mode Control and Current Mode Control. Before implementing any hardware model complete analysis is necessary through suitable software. ORCAD PSpice is most commonly used software for circuit analysis. In PSpice Closed loop switch model and closed loop average model are simulated to verify all the design constraints. Hardware model based on Voltage Mode Control is also developed.