Apparatus and method for controlling permanent magnet electric machines

A method of generating a reference current for controlling a permanent magnet machine, comprising:

• determining an open-loop magnetizing reference current;
• generating a feedback term based on the rotor speed of the permanent magnet machine and a torque current error;
• and
• subtracting the feedback term from the open-loop magnetizing reference current to generate the reference current.

A computer-usable medium storing a software program comprising:

• means for determining an open-loop magnetizing reference current for a permanent magnet machine;
• means for generating a feedback term based on the rotor speed of the permanent magnet machine and a torque current error;
• and
• means for subtracting the feedback term from the open-loop magnetizing reference current to generate a total magnetizing reference current.

A controller, comprising:

• a first software routine for determining a magnetizing reference current and a torque reference current based on one or more inductance saturation curves at peak torque points for a permanent magnet motor;
• a second software routine for computing an output magnetizing reference current by subtracting from the magnetizing reference current a feedback term based on the rotor speed of the permanent magnet motor and a torque current error, the torque current error being the difference between the torque reference current and a feedback torque current from the permanent magnet motor;
• and
• a processor for executing the first and second software routines.