Nice girl with an interesting accent.
But frankly, I think you're a bit in over your head here.
Changing a BLDC motor drive from trapeziodal to sinewave does not make it a PMSM drive. The two drive strategies are two completely different things, although the motor itself looks/is the same.
The PMSM drive is an open-loop system, where the idea is to run the motor as any other synchronous motor. Synchronous motors need starting help to get them into synchronous operation.
Sensorless BLDC motors also need help when starting, eg, bringing the rotor to a known state before operation. When the BLDC motor has reached a certain speed, the back EMF will start controlling commutation. In other words, the rotor position will control your switching pattern (just like a mechanical commutator). This only works at higher rpms.
FOC is a completely different animal, where the "transformer-like" mutual inductance between stator and rotor in induction motors is used for modulation in the control loop.