Broadly-Applicable Accurate Analytical Steady-State Model for Class-E Inverters

This paper presents an accurate closed-form analytical steady-state model for class-E inverters that is broadly applicable. This model is developed using a recently proposed modeling approach for power converters termed Laplace Based Steady-State Modeling (LBSM). Following the LBSM approach, the dynamics of the class-E inverter are modeled using an ordinary differential equation (ODE) with periodic and discontinuous inputs expressed in terms of one of its state variables, and the initial values of the state variable and its derivatives under steady-state operation are determined in closed-form, enabling the determination of closed-form expressions for the steady-state waveforms of the class-E inverter. The presented model is validated using simulation and experimental results for a conventional large ("choke") input inductor class-E inverter. The value of the proposed model is demonstrated by using it to design a finite input inductor class-E inverter in which the inductance of the input inductor is selected such that it helps achieve zero-voltage switching (ZVS) for a range of loading conditions. It is shown that the proposed approach results in a design with a more appropriate inductance value for the input inductor than previous approximate design approaches based on fundamental harmonic analysis or simulations.