Estimation of transformer parameters and loss analysis for high voltage capacitor charging application

In a bi-directional DC-DC converter for capacitive charging application, the losses associated with the transformer makes it a critical component. In order to calculate the transformer losses, its parameters such as AC resistance, leakage inductance and self capacitance of the high voltage (HV) winding has to be estimated accurately. This paper analyzes the following losses of bi-directional flyback converter namely switching loss, conduction loss, gate drive loss, transformer core loss, and snubber loss, etc. Iterative analysis of transformer parameters viz., AC resistance, leakage inductance and stray capacitance of the HV winding will lead to a considerable reduction in converter losses. In this work, a 24 V to 2.5 kV bi-directional flyback converter has been implemented and the same has been used for loss calculation.