Patent ID: 6841969

Claim:
A control system that includes a field oriented controller that receives a torque command and that generates phase voltages for an electric machine including a rotor and a stator, comprising: a first transformation module that receives stator terminal currents from the electric machine and that generates d-axis and q-axis stationary frame currents; an open loop flux observer that receives d-axis and q-axis stationary frame voltage commands and an estimated rotor angular velocity and that includes: a vector cross product calculator that generates an error signal that is proportional to an angular difference between an estimated stator flux and a computed stator flux; and a proportional integral controller that generates an estimated rotor angular position based on said error signal; and a second transformation module that receives said d-axis and q-axis stationary frame currents, said estimated rotor angular position and said estimated rotor angular velocity and that generates d-axis and q-axis synchronous reference frame feedback currents that are output to the field oriented controller.