Hi everyone,
I am working on a series partial-power DAB converter and would like to implement Extended Phase Shift (EPS) modulation.
My goal is not just to transfer the required power, but to generate the optimal inner and outer phase shifts that minimize:
- Backward (circulating/reactive) power
- RMS current
- Peak current (if possible)
while maintaining the desired transmitted power.
Converter specifications
- Series partial-power DAB
- Forward boost operation (300 V → 400 V)
- Transformer turns ratio: 2.5:1
- Leakage inductance: 8.94 µH
- Switching frequency: 100 kHz
My question
Suppose I know:
- Input voltage
- Output voltage
- Transformer turns ratio
- Leakage inductance
- Switching frequency
- Desired transferred power
How do I determine the optimal inner phase shift and outer phase shift for EPS?
In particular:
- Is there a closed-form method to calculate them?
- Is numerical optimization (grid search,
fmincon, etc.) the usual approach? - How do you ensure that the selected phase shifts minimize circulating/backflow power and RMS current rather than simply satisfying the power equation?
- Are there practical constraints that should be enforced during the optimization?
I’m interested in understanding the design methodology rather than just obtaining one operating point.
If anyone has implemented an EPS optimizer or can explain the workflow used in practice, I would really appreciate the guidance.
Thank you!
