GSSA Modeling and Excitation Optimization for Adjacent Coils in Dynamic Wireless Power Transfer Systems

Dynamic wireless power transfer (DWPT) technology can achieve charging for devices on the move, like automated guided vehicles, which can dramatically improve their working efficiency. In this paper, the generalized state-space averaging (GSSA) model of the DWPT system is established, where the state equations are derived in accordance with the equivalent circuit, and then all state variables are separated into sine and cosine items using the Fourier series. The established model reveals that the maximum efficiency points of the DWPT system are correlated with the phase differences between currents of two adjacent transmitting coils at different mutual inductance conditions. As a result, the system's efficiency can be optimized by adjusting the phase differences of transmitting currents. Finally, numerous simulations and experiments are conducted to verify the GSSA model. The results prove the high accuracy of the model, and the efficiency calculation errors are less than 0.21% and 2.38% when the phase differences are 0 and -89 degrees, respectively. The model exhibits only a one-degree error in tracking the maximum efficiency point when the receiver is located 5 cm away from the reference position. Additionally, the closed-loop experiments demonstrate that the efficiency optimization is achieved by tuning the Tx current's phase. © 2025 IEEE.