Time-domain steady-state modeling of series-parallel resonant converter under optimized modulation

In this contribution the frequency-domain modeling techniques for resonant converters under optimized modulation are reviewed. As a general modeling technique, the standard AC fundamental harmonic approach is suitable for all resonant converter topologies. However, it becomes inaccurate if the current or voltage of the resonant tank is distorted from sinusoidal waveform. The extended AC fundamental harmonic approach provides a much higher modeling accuracy, but it lacks generality. In order to overcome these drawbacks a general, systematic time-domain modeling procedure with high modeling accuracy is introduced and demonstrated by a series-parallel resonant converter with LC output-filter under optimized modulation. Verification with experimental results is given.