Performance Analysis of an Isolated ZVT Boost Converter with Primary-Parallel-Secondary-Series (PPSS) Structure

The primary-parallel-secondary-series structure is employed in this paper to share the large current at the primary side and to sustain the high voltage at the secondary side in the isolated low-input-to-high-output applications. A novel boost converter with coupled inductors and an active-clamp circuit is proposed for high power and high step-up conversion. Only one set of clamp circuit is necessary to serve for the interleaved two phases, which reduces the auxiliary switch number and simplifies the circuit. ZVT soft switching performance is achieved to reduce the switching losses for both the main and the auxiliary switches during the whole switching transition. The leakage energy of the coupled inductors is recycled and the output diode reverse-recovery problem is alleviated. The steady operation and the circuit performance are analyzed. And the design considerations are given. At last, the simulated and experimental results for a 40V-to-760V converter verify the converter performance.