Constant Current and Voltage Charging for Wireless Charging Systems Based on an Ultra-simple Secondary Side Integrated Rectifier and Power Adjustment Circuit

Aiming to achieve a compact receiver for wireless charging systems (WCSs), this letter proposes an integrated rectifier and rower adjustment (IRPA) circuit, featuring an ultra-simple structure by using only one MOSFET, one diode, and one filter capacitor, to achieve constant current (CC) and voltage (CV) charging via a dual-loop cascade PI controller. A comparison between the IRPA circuit and two similar existing methods shows the advantages of the IRPA circuit. Then, the WCS with the IRPA circuit's structure and its operating modes is analyzed. The relationship between the charging current and duty cycle of the PWM signal for driving the IRPA circuit is illustrated, along with an analysis of the IRPA circuit's power adjustment range. The working principle of the closed-loop control strategy for CC and CV charging is analyzed, along with simulation verification. Finally, an experimental setup is built, and the maximum output power and system efficiency are 378 W and 92.4%. Combined with the existing literature, the IRPA circuit is regarded as a simple method to realize the WCS's secondary side power adjustment.