An Enhanced TPS Modulation Strategy With Full‐Range ZVS for LCL‐Type Resonant DAB Converter

ABSTRACT This paper presents an enhanced triple‐phase shift (ETPS) modulation strategy for the inductor–capacitor–inductor (LCL) type resonant dual active bridge (DAB) converter. By analyzing the zero‐voltage switching (ZVS) conditions and operating modes using fundamental harmonic approximation (FHA), the proposed ETPS strategy adaptively adjusts the phase shift angles to ensure ZVS across the full operational range, particularly over a wide voltage conversion range. Furthermore, for both buck and boost modes, the total root‐mean‐square (RMS) current is minimized using the Lagrange multiplier method (LMM) to reduce conduction losses. Closed‐form analytical expressions for the optimal phase shift angles are derived to enable efficient power regulation. The effectiveness of the proposed strategy is validated through simulations and confirmed by experimental results, which demonstrate that the ETPS strategy consistently achieves ZVS under various load conditions and outperforms the conventional unity power factor (UPF)–triple‐phase shift (TPS) strategy in terms of efficiency.