High Leakage Inductance Research Articles

Ohmic losses calculation in SMPS transformers: numerical study of Dowell's approach accuracy

The paper compares two methods for ohmic losses calculation in switch-mode power supply transformers: Dowell's 1D approach and 2D finite element method simulations (validated by measurements). Dowell's method underestimates losses at the fundamental frequency for foil windings, whereas harmonic losses are generally overestimated (depending on conductor type). More significant differences are found with high leakage inductance transformers.

Analog equivalent circuit aided design of ferroresonant transformers and circuits

This paper shows how an analog equivalent circuit of the ferroresonant series-connected secondary capacitor and high-leakage inductance transformer type may be used to design ferroresonant type regulating circuits for supplying power to nonlinear loads. The functions of a high-leakage inductance transformer are provided by two linear variable inductors and an adjustable highly nonlinear inductor. The functions of the nonlinear loads are provided by a biased diode type of load consisting of a bridge rectifier loaded by a large capacitor, shunted by a variable resistor, and in series with a small resistor or linear inductor. The series resistor simulates the dynamic resistance of a magnetron and the linear inductor simulates the dynamie characteristics of high pressure mercury vapor type of lamp loads. The parameters of the analog circuit are varied until the desired degree of regulation of output current and power vs. percent of supply line input voltage is had without excessive values of peak output current. The parameters are then reduced by calculation to a set of dimensionless parameters for use in designing the required high-leakage-inductance transformer and for specifying the value of the capacitor required in series with the transformer secondary.