A method for controlling an electric machine in a powertrain system in which a driven load is connected to a rotor of the electric machine includes measuring phase currents at a starting point of a sample period using current sensors connected to phase windings of the electric machine. The individual phase currents also are determined at a midpoint of the previous sample period. An angular position of the rotor is determined at the starting point and previous midpoint before calculating synchronous reference frame currents of the electric machine at the starting and previous midpoint using the phase currents and angular position. The method includes calculating average synchronous reference frame currents over the sample period and regulating operation of the electric machine using the average. An electrical system includes the electric machine, a power inverter module, and a controller that executes the method.