Design of a Load Invariant Class-E Amplifier for an Inductively Heated Fluidized Bed

This paper presents the design and implementation of a Class-E power amplifier invariant to both resistive and reactive load changes for inductively heating a fluidized graphite bed. The 66.5 V amplifier is capable of delivering up to 115 W to the varying load at 13.56 MHz. Tuned to the load impedance profile, the design utilizes a passive load transformation network to decrease the root mean square input current and compress output network phase angle variation to achieve zero-voltage switching across the entire load range.