Consideration of conduction losses for the series resonant converter by means of a simple extension to the SPA approach

The cumbersome derivation of the steady-state characteristics of resonant converters can be simplified by means of the state-plane analysis. Under the assumption of ideal components, a closed-form solution can be derived in case of the series resonant converter above the resonant frequency. However, losses due to parasitic resistances cannot be easily included within this approach. Nevertheless, a more precise prediction of the converterpsilas output characteristics taking the conduction losses into account is desirable. Therefore this paper describes a simple extension to the regular approach that leads to better agreement with measurements. This approach is based on the results derived under ideal assumptions, thus avoiding a more complicated and tedious analysis including the conduction losses.