Explain the Dual Active Bridge (DAB) converter operation and control.

The DAB uses two full-bridge circuits coupled through a high-frequency transformer, enabling bidirectional power flow. Phase-shift between primary and secondary bridges controls power transfer: P = (Vp*Vs*phi*(pi-|phi|))/(2*pi^2*fsw*L). The leakage inductance acts as energy transfer element. ZVS is achieved over wide load range with proper design. Extended phase shift and triple phase shift reduce circulating current and extend ZVS range. Applications include EV charging, solid-state transformers, and energy storage interfaces. Control must handle bidirectional operation and transient events.