Patent ID: 8227951

Claim:
A permanent-magnet synchronous machine for three-phase operation, comprising: a stator having plural teeth, each tooth surrounded by a winding, said stator having a number of holes q=½ which is defined as q=N1/(3×2p), wherein N1 is the number of stator slots; 3 is the number of phases; and 2p is the number of poles of the rotor; and a rotor defining an axis and having permanent magnets arranged in a circumferential direction with a pole gap in a range from 20% to 42.9% in relation to a pole pitch, the rotor having a skew with a skew angle on an axial projection in the circumferential direction of 40% to 57.2%, in relation to the pole pitch, wherein a ratio of the skew angle/pole pitch to a ratio of the pole gap/pole pitch is schdpt=−0.75×pldpt+72.2%, with schdpt being the ratio of the skew angle/pole pitch, and pldpt being the ratio of the pole gap/pole pitch, and wherein the pole gap and the skew are designed such that oscillating torques caused by the fifth and seventh harmonics of a stator field and of a rotor field are mutually reduced.