Constant Current/Voltage Charging Operation for Series-Series and Series-Parallel Compensated Wireless Power Transfer Systems Employing Primary-Side Controller

This paper proposes a new control technique, which only employs the primary-side controller and load identification approach to adjust charging voltage/current for series-series (SS) and series-parallel (SP) compensated wireless power transfer (WPT) systems. The advantages are that dual-side wireless communication for real-time charging current/voltage adjustment is avoided as well as it is suitable for different charging modes, e.g., constant voltage (CV) and constant current (CC) charging defined by the battery charging profile. The load identification approach, which utilizes reflected impedance theory and quadrature transformation algorithm for calculating the active power, is proposed to estimate the equivalent load resistance of battery. Then, the CV/CC charging for both SS and SP compensation are achieved by the PI-controlled phase-shift H-bridge inverter. The simulation and experimental results validate the feasibility of proposed control method. During the CC charging, 3.01 and 3.03 A for SS and SP compensation with the error of 1.2% and 1.4% are achieved. During the CV charging, 25.8 and 25.7 V for SS and SP compensation with the error of 1.1% and 1.3% are realized. The proposed method improves the performance of both SS- and SP-compensated WPT systems to be more suitable for the applications that require compact and lightweight receiver.