## 2 Modeling
### Non-Ideal Equivalent Circuit Model  
The circuit in Figure 1 is only a simple approximation of the real operation of the practical push-pull converter, so an accurate model will require consideration of the non-idealities of the real push-pull converter. Thus, it is necessary to have a complete model, which integrates the non-idealities of the converter while combining the characteristics of accuracy and simplicity. Considering the non-idealities of the push-pull converter, which can be innumerable, it is necessary to limit their number to those that have a real influence in practice. In addition, unpredictable non-idealities, such as those due to poor converter design and construction, must be avoided, for example the type of connections used, the design of the printed circuit board, the wiring, the design of the gate-driver circuits, poor sizing and construction of the HF transformer, and the use of poor-quality components. In view of the above, to consider an approachable modelling problem, it is necessary to ensure that the converter has been designed and built correctly and that its components are of professional quality. All the considered non-idealities and assumptions used in the modeling will be described below. For the modelling of the HF transformer, the well-known non-ideal transformer model T with parameters reduced to the secondary will be used. Then, to set up the practical circuit, and based on the practical principle being described, it is considered that the transformer is well designed, which makes it possible to assume that the transformer will be fully magnetized and demagnetized in each operating cycle, its core will always operate within the linear region of the magnetization curve, and its parameters will be identical for each winding. In addition, the parasitic inductances and resistances associated with the power loop, wiring and connectors will not be considered, since the casuistry can be enormous as these parameters depend on the design and physical implementation of the converter. In any case, these parameters are relatively easy to minimize with good converter design and manufacturing. The non-idealities considered for power switching devices are series drain-sink saturation resistance and parallel output capacitances for Mosfets, direct resistance, and the corresponding threshold voltage for rectifier diodes. Switching losses have not been considered in this analysis for several reasons. The first is that these losses are influenced by parameters external to the converter, which are difficult to control or know, such as the output voltage or resistance of the gate driver circuit of the power transistors. This leads to the second reason: the limitations of the complexity of the model. The consideration of switching losses would add further complexity to the already high order of the model. Moreover, considering as the article considers the switching devices to be of good quality, and as the switching times are much lower than the conduction times, losses can be considered negligible. For diodes and electronic switches, the characteristics and non-idealities associated with devices of the same model and manufacturer shall be considered identical. On the other hand, it is known that there are strong non-linear relationships in the diode with respect to its threshold voltage and, in the case of electronic switches, with respect to the drain-sink voltage (output capacitance) and the influence of temperature on the drain-sink resistance. However, to ensure that the analysis is not unnecessarily complex and there is no loss of generality, constant parameters will be taken, which are linked to the current operating conditions of voltage, current and temperature electronic switches at a given sampling time. Accordingly, the model can easily be adapted to the specific operating conditions at each sampling time.