Controlling an electric motor

A method for controlling an electric motor comprising the steps of:

• a) choosing current turn-on and turn-off rotor-position angles for each motor phase to substantially maximize the absolute value of average motor torque when the motor is operating at a motor speed in a first quadrant of positive motor torque and positive motor speed;
• b) choosing current turn-on and turn-off rotor-position angles for each motor phase to substantially maximize the absolute value of average motor torque when the motor is operating in a second quadrant of negative motor torque and positive motor speed;
• c) choosing current turn-on and turn-off rotor-position angles for each motor phase to substantially maximize the absolute value of average motor torque when the motor is operating in a third quadrant of negative motor torque and negative motor speed;
• d) choosing current turn-on and turn-off rotor-position angles for each motor phase to substantially maximize the absolute value of average motor torque when the motor is operating in a fourth quadrant of positive motor torque and negative motor speed;
• and
• e) operating the motor in each of the first, second, third, and fourth quadrants.

A method for controlling an electric motor comprising the steps of:

• a) operating the motor in at least one of a first quadrant having positive motor torque and positive motor speed and a third quadrant having negative motor torque and negative motor speed;
• b) operating the motor in at least one of a second quadrant having negative motor torque and positive motor speed and a fourth quadrant having positive motor torque and negative motor speed;
• and
• c) limiting the absolute value of motor speed when the motor is operating in the first or third quadrant but not when the motor is operating in the second or fourth quadrant.

A method for controlling an electric motor operatively connected to a vehicle brake caliper comprising the steps of:

• a) choosing current turn-on and turn-off rotor-position angles for each motor phase to substantially maximize the absolute value of average motor torque when the motor is operating at a motor speed in a first quadrant of positive motor torque and positive motor speed;
• b) choosing current turn-on and turn-off rotor-position angles for each motor phase to substantially maximize the absolute value of average motor torque when the motor is operating in a second quadrant of negative motor torque and positive motor speed;
• c) choosing current turn-on and turn-off rotor-position angles for each motor phase to substantially maximize the absolute value of average motor torque when the motor is operating in a third quadrant of negative motor torque and negative motor speed;
• d) choosing current turn-on and turn-off rotor-position angles for each motor phase to substantially maximize the absolute value of average motor torque when the motor is operating in a fourth quadrant of positive motor torque and negative motor speed;
• e) operating the motor in each of the first, second, third, and fourth quadrants;
• and
• f) limiting the absolute value of motor speed when the motor is operating in the first or third quadrant but not when the motor is operating in the second or fourth quadrant.