Asymmetric Control System For a Sensorless and Brushless Electric Motor

A method for the commutation of the motor phases of a multi-phase electric motor, comprising the steps of:

• controlling for one full cycle at least one motor phase in an asymmetrical manner relative to a further motor phase by controlling a commutation angle of one motor phase in a shortened way with respect to a corresponding commutation angle of the other motor phase, or
• controlling for one full cycle at least one motor phase asymmetrically with respect to itself by controlling a commutation angle in a shortened way with respect to a preceding or subsequent commutation angle or by providing intermediate angles of different sizes between two commutation angles,
• wherein the shortened commutation angle is preceded or followed by a measurement angle within which the relevant motor phase is switched at zero current for detecting a rotor position by measuring the counter-electromotive force.

A method for the commutation of the motor phases of a multi-phase electric motor, comprising the steps of:

• controlling for one full cycle at least one motor phase in an asymmetrical manner relative to a further motor phase by controlling a commutation angle of one motor phase in a shortened way with respect to a corresponding commutation angle of the other motor phase, or
• controlling for one full cycle at least one motor phase asymmetrically with respect to itself by controlling a commutation angle in a shortened way with respect to a preceding or subsequent commutation angle and by providing intermediate angles of different sizes between two commutation angles,
• wherein the shortened commutation angle is preceded or followed by a measurement angle within which the relevant motor phase is switched at zero current for detecting a rotor position by measuring the counter-electromotive force.