A Phase Shift + Frequency Hybrid Modulation Scheme for FBLLC Converter to Achieve Reduced Modulation Frequency Range Over Bidirectional Power Flow

Charging infrastructure development with energy storage and improved efficiency, plays a major role for the progress of electric vehicle (EV) markets. In this work, a control method for improving bidirectional charging performance is proposed in which, hybrid modulation of bridgeless interleaved totem pole power factor correction (PFC) combining series resonant converter with reduced frequency-range control is used. For extraction of grid angle a frequency-fixed second order generalized integrator (FF-SOGI) based phase locked loop (PLL) is used. The controller is designed to lower Electro Magnetic Interference (EMI), switching and conduction losses. Symmetrical gating used in secondary side of series resonant converter at backend helps to reduce higher average current and uneven thermal stress on secondary side switches in place of asymmetrical gating. The control mode selection depends upon secondary side output voltage. The reduced switching frequency is achieved by tracing output voltage using two control methods i.e., phase shift control and variable frequency control. The control of the primary switches is achieved through variable- frequency control whereas secondary side switch rectifiers are controlled through phase shift control. This circuitry exhibits maximum power transfer of 6.6 kW and simulated for the evaluation of designed charging model.