An interior permanent magnet machine includes a rotor having a plurality of slots. First and second slots are disposed in a first pole and the third and fourth slots are disposed in a second pole. A first barrier is defined by the first, second, third and fourth slots. The slots are configured to be symmetric relative to their respective pole axes. A first angle is defined between the first and second slots. A second angle is defined between the third and fourth slots. The first angle is configured to be sufficiently different from the second angle so that torque ripple is minimized. Thus the rotor is configured such that the angular configuration of slots in a first pole is different from the angular configuration of slots in a second pole of the rotor.