Method for operating a delta wound three-phase permanent magnet brushless motor

A method for operating a delta wound three-phase permanent magnet brushless motor comprising the steps of:

• a) determining a transition motor speed of the motor in a quadrant of a motor speed versus motor torque curve of the motor above which motor speed continues to increase while motor current/torque decreases wherein actual phase current supplied to the motor can be controlled by a motor controller in a current control modification manner which reduces requested phase current for the motor;
• b) determining the current control modification manner for a quadrant of the motor speed versus motor torque curve, wherein the motor controller can use the current control modification manner to reduce the requested phase current to control the actual phase current when the motor speed is above the transition motor speed;
• and
• c) controlling the motor in a quadrant of the motor speed versus motor torque curve with the motor controller wherein, when the motor has a motor speed above the transition motor speed, the motor controller reduces the requested phase current in the current control modification manner and the motor controller supplies the actual phase current to the motor based upon closed loop control using the reduced requested phase current and using measured phase current of the motor derived from using a single current sense resistor.