A Design Method for LCC Resonant Converter over Wide Load Range with Wide-range Input and Output

摘要

Based on the First Harmonic Approximation (FHA) model of LCC resonant converter (CCM mode PFM control), this paper analyses and elaborates the mutual restriction relationship between LCC parameters. Subsequently, an intuitive design method is proposed to realize the gain capability of LCC resonant converter over wide load range with wide-range input and output. And a light load optimization using double inductors is presented to reduce the high switching frequency and reactive current under the light-load mode. Key parameters are given according to the specific requirements in this paper. Finally, the gain capability and the effect of the light load optimization are validated by the experimental results of a prototype with input 483-591V, output 40-150kV, output 1A(max) and output 80kW(max). The gain requirement can be satisfied remarkably, the frequency range of the system is optimized from 59.7-130.3kHz to 52.2-94.1kHz, and the resonant current is greatly reduced under the light-load mode.