A hybrid control strategy for dynamic compensation of cross-coupling effect in two-load IPT system

The cross coupling between receiver coils complicates the control and optimization of "one-to-may" multi-load IPT systems. In this paper, the cross-coupling effect in a two-load IPT system is thoroughly discussed. It is noted that the input impedance, the total output power and the power distribution ratio among receivers are all affected. After developing a new leakage-inductance-based model considering the cross-coupling effect, it is suggested that the operating frequency is adjusted according to the cross-coupling coefficient to ensure a constant power distribution ratio. The total output power and the input impedance are regulated by coordinated adjustment of the inverter's duty cycle and the transmitter-side compensation capacitance with switched control capacitor (SCC) control. Based on the proposed hybrid control strategy (frequency, duty cycle, and SCC), the power distribution among loads and the total output power are kept constant under variable cross-coupling coefficient, and the input impedance are shaped to be inductive to achieve zero voltage switching (ZVS) realization for all switches in the inverter. The theoretical analysis is finally verified by experimental results on a 35 W two-load IPT prototype.