Pulse Density Modulation Control of LCC-S Compensated WPT System with Switch-Controlled Capacitors for Constant Output Voltage of Frequency-Selective Receivers

Multi-frequency receivers WPT systems have received wide attention. The selectivity of power transfer target and stable output voltage are two key issues. The traditional phase shift modulation (PSM) control has the disadvantage of hard switching when it operates at light load. Besides, it has to increase the capacitor branches to maintain the consistency of the characteristics of the compensation network under different operating frequencies. These issues increase the switching loss and the complexity of the system. In this paper, the dynamic change of compensation parameters is realized with the help of switch-controlled capacitor (SCC), and then the selectivity of the receivers is achieved. Moreover, the output voltage control and ZVS operation are realized based on pulse density modulation (PDM) control. After that, a 1 to 3 WPT system is proposed and the implementation method is discussed. The experiments are carried out to verify the proposed analysis and control method.