I'm trying to tune speed regulator PI in EVAL-M1-099M with IRMCK099M.
When I reduce speed regulator PI, motor (PMSM) rotates smoothly at low speed. But when I load the motor, it first brakes and only after a second restores speed.
If I increase speed PI gain the motor practically does not brake under load, but at low speed the motor runs with jerks.

How can I achieve a smooth motor rotation at low speed and good speed maintenance?