A method for controlling transient operation of a variable flux machine (VFM) includes, during a shunt angle transition, receiving a commanded and measured shunt angle when operating in a predetermined operating region, e.g., maximum torque per ampere or field weakening. The method includes calculating d-axis and q-axis delta current terms (ΔId and ΔIq) required to maintain an output torque level of the VFM through a duration of the shunt angle transition, then applying the required ΔId and ΔId terms as feed-forward terms to adjust a d-axis current (Id) term and a q-axis current (Iq) term from a respective lookup table. In this manner the controller maintains the output torque level of the VFM during the shunt angle transition. An electric powertrain includes the VFM, a TPIM, and the controller. A PM machine may be controlled by substituting temperature for shunt angle.