Small-Signal Phasor Modeling of T-Type Bridge-Based Single-Sided and Double-Sided LCC Resonant Converters for WPT Applications

Wireless power transfer systems often utilize dc-dc resonant converters with single-sided or double-sided LCC resonant networks for effective power conversion. With the increasing prevalence of LCC networks, this paper investigates a dc-dc resonant converter comprising a T-type bridge, single-sided and double-sided LCC resonant tanks, and an isolated diode-bridge rectifier connected to a battery load, and conducts a thorough small-signal analysis. The study employs phasor transformation-based small-signal modeling, which provides clear and intuitive insights into the model derivation. The precise model presented here enhances the design and stability of closed-loop feedback control, resulting in more reliable and efficient power delivery. The proposed analysis is validated through simulations conducted on a 20 kW T-type bridge-based dc-dc converter that incorporates an LCC resonant network. Additionally, hardware testing of a 4 kW, 85 kHz dc-dc resonant converter prototype further substantiates the accuracy of the small-signal modeling process for perturbation frequencies up to 55 kHz.