Dual Active Bridge (DAB) Converter – III | Phase Shift Control | Power Flow Analysis | Electric Vehicles | Lecture 09

The Dual Active Bridge (DAB) Converter is one of the most widely used isolated bidirectional DC–DC converters in electric vehicles, battery energy storage systems, and DC microgrids. In this lecture, we explore how phase-shift control regulates the magnitude and direction of power transfer between the two active bridges. The operating principles are explained using switching waveforms, current paths, and practical examples.

This lecture demonstrates the effect of different phase shift angles (δ = 0°, 45°, 90°, 135°, 180°, and 225°) on power transfer. You will learn why power transfer is positive when the phase shift lies between 0° and 180°, reaches its maximum at 90°, becomes negative when the phase shift is between 180° and 360°, and achieves maximum reverse power transfer at 270° (or −90°). The equivalent circuit of the DAB converter is also introduced to explain the influence of leakage inductance and phase shift on converter operation.

A practical 400 V to 800 V EV charger example is presented using a transformer turns ratio of 1:2, along with detailed analysis of inductor voltage, current waveforms, and switching states under Single Phase Shift (SPS) control.

Topics Covered

Review of Dual Active Bridge (DAB) Converter
Phase Shift (δ) Control Technique
Positive and Negative Power Transfer
Maximum Power Transfer Condition
Effect of Different Phase Shift Angles
Equivalent Circuit of the DAB Converter
Role of Leakage Inductance
High-Frequency Transformer Operation
Single Phase Shift (SPS) Control
400 V to 800 V EV Charging Example
Inductor Voltage and Current Waveforms
Switching Sequence and Power Flow Analysis

Who Should Watch?

B.Tech. and M.Tech. students
Power Electronics learners
Electric Vehicle enthusiasts
GATE and ESE aspirants
Researchers working on isolated DC–DC converters
Engineers designing EV chargers and battery energy storage systems

Recommended References

R. W. Erickson and D. Maksimović, Fundamentals of Power Electronics, 2nd Edition, Springer.
A. R. Rodríguez, J. Sebastián, D. G. Lamar, M. M. Hernando, and A. Vázquez, An Overall Study of a Dual Active Bridge for Bidirectional DC/DC Conversion, IEEE ECCE 2010.

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