Abstract: An electric motor (19) comprises a first part (21) and a second part (23) which are moveable with respect to each other. The first part comprises a foil-shaped insulating substrate (51) on which a plurality of series-connected spiral-shaped patterns (67, 67?, 69, 69?, 71, 71?) of conductor tracks are provided. The second part comprises a permanent magnet unit (73) for generating a magnetic field at the location of the conductor tracks. Said patterns each comprise two main sections (79, 81) with substantially straight, parallel conductor tracks (83, 85) having first ends (89, 93) and second ends (91, 95), and two intermediate sections (97, 99) with curved conductor tracks (101, 103) which respectively mutually connect the first ends of the two main sections and mutually connect the second ends of the two main sections. Said intermediate sections each have a center area (105, 107) respectively halfway between the first ends of the two main sections and halfway between the second ends of the two main sections.

Abstract: An increasing number of phases in multiphase converters causes an increase in requirements with respect to the control IC. According to the present invention, instead of deriving a new PWM signal for every single phase of the DC-DC converter, the single phases are clustered into groups (22, 24, 26). Within each group, the converters are operated on the basis of one PWM signal (PW M1, PW M2 . . . PW MN). Advantageously, this may allow to reduce the requirements with respect to the control IC and thus may allow the application of cheaper and smaller control ICs.

Abstract: An electric motor (19) comprises a first part (21) and a second part (23) which are rotatable with respect to each other about an axis of rotation (9). The first part comprises a foil-shaped insulating substrate (51) on which a plurality of series-connected spiral-shaped patterns (67, 67′, 69, 69′, 71, 71′) of conductor tracks are provided. Said substrate is bent so as to form a circular-cylindrical body (29), which extends, seen in a direction parallel to the axis or rotation, between a first and a second imaginary end surface (59, 61), and which is mounted on a carrier (2) near the first end surface (59). The second part comprises a permanent magnet unit (73) for generating a magnetic field at the location of the conductor tracks. The first part is provided with connector means (79) for connecting the conductor tracks to an electrical energy source.