VERSATILE CONTROL USED FOR LLC RESONANT CONVERTER SUITABLE FOR PORTABLE APPLICATIONS

Conventional voltage mode control with one of the Pulse Analog Control Schemes called Pulse - Position Modulation (PPM) offers only limited performance for LLC resonant DC/DC converters undergoing wide variations in operating conditions. This paper presents current mode control with PPM that could consistently provide good dynamic performance for LLC resonant DC/DC converters irrespective of wide variations in operating conditions. The proposed versatile control scheme employs additional feedback from the current of the resonant tank network with an integrator - type compensation amplifier which improves the dynamic performance, enhances the noise immunity and the reliability of feedback controller to overcome the limitation of the existing voltage mode control. Significance of current mode control over voltage mode control is presented by providing necessary design guidelines and simulation results incorporated with PPM. The design of LLC resonant convert er uses Fundamental Harmonic Approximation (FHA) with maximum gain adjustment.