Fifth-order state-space modeling of class E amplifiers with finite-series inductance and an anti-parallel diode at the switch

A state-space model is developed to enable a general analysis of the class E amplifier with a power-MOSFET switch under nonoptimal and optimal conditions. That is, it permits analysis of nonzero voltage switching and nonzero current switching operation, as well as the optimal zero voltage switching (ZVS) and zero current switching (ZCS) condition. This is achieved by improving the representation of the power MOSFET switch by the inclusion of a series inductance, a model for the on-state resistance and switching time, and a model for the anti-parallel body diode. An optimal 100-kHz class E amplifier was designed and constructed, using the model to choose component values. Experimental results show good agreement with the predictions of the state-space model for both optimal and nonoptimal operating conditions.