A Class-E2 wireless power transfer system with different efficiency curves

Class-E inverters and Class-E rectifiers are combined to compose isolated Class-E
²
DC/DC converters to transfer power through loosely coupled inductive coils. A design method for this converter is discussed to achieve ZVS (zero-voltage switching) and ZDS (zero-derivative switching). The converter is operated in a fix-frequency and open-loop mode. Load characteristics for this converter are analyzed in graphs including the relations among output voltage, output current and efficiency. High impedance design fitting for light load and load insensitive design fitting for heavy load are introduced to get different efficiency curves, which are suitable for different load probability distribution in different applications.