MATLAB Simulation for Dual Active Bridge DC-DC Converter
- lms editor
- 5 hours ago
- 3 min read
🔋 Introduction
The Dual Active Bridge (DAB) DC–DC Converter plays a pivotal role in medium- and high-power energy conversion systems such as EV chargers, renewable energy interfaces, and solid-state transformers. In this MATLAB-based simulation, we explore how the DAB topology efficiently regulates voltage through bidirectional power flow using high-frequency isolation and phase-shift modulation (PSM).
The primary objective is to demonstrate how the converter maintains a regulated and stable output voltage that dynamically tracks reference variations (14 V–24 V), ensuring precise voltage regulation under varying load and operating conditions.
⚡ Simulation Setup
🧩 Active Bridge Configuration
The converter consists of two full bridges—one on the input side and another on the output side—linked via a high-frequency transformer.
This enables galvanic isolation and bidirectional power flow, allowing seamless energy transfer between DC ports.
🔌 Input and Output Voltages
Input Voltage (Vin): 16 V (fixed)
Output Voltage (Vout): Variable, 0 V–24 V range
The DAB’s control strategy aims to track the reference output voltage, alternating between 24 V and 14 V every 100 ms.
⚙️ Control Logic
A Proportional–Integral (PI) Controller regulates the output voltage.
The controller continuously compares measured output voltage with the reference voltage (Vref) and generates a phase-shift control signal (φ).
Phase-Shifted Modulation (PSM) governs the switching operation of the bridges:
Adjusting φ changes the effective power transferred through the transformer.
A positive φ directs power from input to output; reversing φ allows bidirectional flow.
🔄 Voltage Reference Variation
To analyze the system’s transient response, the reference voltage alternates between 24 V and 14 V at 100 ms intervals.
This enables observation of dynamic behavior, settling time, and tracking precision under varying voltage demands.
📊 Simulation Results
✅ Output Voltage Tracking
The simulation reveals excellent voltage tracking performance.
Despite rapid shifts in reference voltage, the output voltage (Vout) accurately follows the Vref trajectory with minimal overshoot.
The PI controller dynamically adjusts the phase angle to ensure smooth transitions and voltage stability.
⚡ Response Analysis
Waveforms of primary and secondary bridge voltages, transformer current, and load voltage/current validate that the converter responds rapidly to reference changes.
The voltage ripple is minimal, confirming the effectiveness of both filtering and modulation techniques.
The phase-shift variation correlates directly with the desired output voltage, demonstrating precise control behavior.
🔍 Reference Tracking Accuracy
When comparing Vref and Vout, the converter maintains a close match even during transients.
The system’s dynamic response shows fast rise and settling times with negligible steady-state error.
This highlights the robustness of the PI control loop and the phase-shift modulation scheme in maintaining accurate reference tracking.
🧠 Analysis and Observations
The high-frequency transformer effectively steps up/down voltage with galvanic isolation.
The phase-shift control ensures soft-switching operation (ZVS) over a broad load range, enhancing system efficiency.
The output voltage regulation remains stable even with varying load and reference voltage, confirming the adaptability of the DAB topology for power electronic systems requiring bidirectional conversion.
🏁 Conclusion
The MATLAB simulation of the Dual Active Bridge DC–DC Converter successfully demonstrates how advanced control strategies—particularly PI-based phase-shift modulation—enable accurate voltage regulation and bidirectional power flow.
Key takeaways include:
Precise tracking of reference voltage variations (24 V ↔ 14 V).
Stable and ripple-free output voltage.
High dynamic response under load disturbances.
Efficient modulation control for flexible energy transfer.
This simulation provides a strong foundation for further exploration of digital control, ZVS optimization, and hardware implementation of high-efficiency isolated DC–DC converters used in EV charging, energy storage systems, and renewable microgrids.
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