A Communication-Free Fast Constant Current and Voltage Control Method for Dynamic Wireless Power Transfer System

In this article, a communication-free constant current (CC) and constant voltage (CV) Li-ion charging control method for dynamic wireless power transfer (DWPT) systems is proposed. The key challenge of traditional control schemes is the coupled mutual inductance and battery equivalent resistance, which leads them to solely allow either dynamic coupling condition or varying load resistance. In the proposed control method, by adopting an inductive secondary resonator, the mutual inductance and load resistance are decoupled in CV mode. The output current and voltage are controlled by estimating the bias between the real-time state and the reference steady state. The CC and CV modes are switched automatically without bidirectional communication. Hence, the proposed control method is featured with less time delay, fast dynamic performance, and low implementation cost. Both the simulation and experimental results prove that the proposed control scheme has high control precision (less than 4% steady-state error) and short settling time (less than 40 ms) in the CC/CV charging mode.