LLC half-bridge design

Hi all,

currently I develop a half-bridge LLC with centre tapped and I need somre help to optimize my design. My specifications are:

- 400Vdc input to 40-60Vdc output and 35A (output).

- The switching frequency is between 91kHz and 225kHz, resonant frequency 151kHz. 

- Core: PQ50/50 (N97) from TDK.

- Windings: primary 15 turns (38 AWG w 450 strands)

 secondary 3 turns (16 mil copper foil)

- Winding distribution: PSPS: 8-3-3-7

I am operating the converter equal to or below resonance region and the core losses estimation is around 10W and I need to reduce them.

Are the winding pattern and core size correct?