Frequency-time domain combined analysis method for bidirectional wireless power transfer system based on single-stage AC-AC converter

The First-Harmonic Approximation (FHA) analysis method is widely utilized in Bidirectional Wireless Power Transfer (BWPT) systems, providing simplified input and output characteristics. However, in complex systems and varying operating conditions, such as those involving a single-stage AC-AC converter, the FHA method falls short, leading to significant calculation deviations that fail to accurately represent the system's working state, as the same as Traditional Multi-harmonics methods (TMH), and time-domain only derivation methods. This paper introduces a novel Frequency-Time Domain Combined (FTDC) analysis prediction method that enhances the precision of the system's operational analysis through theoretical calculations. The proposed method integrates frequency domain analysis with time domain analysis to reconstruct the system's voltage and current waveforms via data deduction and iteration. Notably, this approach outperforms simulation software by rapidly yielding the steady-state waveform and directly providing essential data, including Root Mean Square (RMS) values, amplitude values, and zero-crossing points. This efficiency aids in the expedited and improved design of the entire BWPT system. Finally, the accuracy and practicality of the proposed method are validated through a combination of theoretical analysis and experimental results.