Phasor Transformation and its Application to the DC/AC Analyses of Frequency Phase-Controlled Series Resonant Converters (SRC)

A new modeling technique based on phasor transformation that provides the unified model of series resonant converters (SRC) is proposed. The proposed approach gives explicit and simple equations with fruitful physical insight. In the case that the switching frequency deviates from the resonant frequency, the SRC is modeled as the first order, and in the case of resonance the SRC is modeled as the second order. It is shown that the frequency band in which the SRC is modeled as the second order is very narrow in practice. The time constant, small signal gains, and system order are highly depend on the switching frequency, load resistor, and output capacitor.