Quasi-resonant-converters-based high-efficiency spindle motor drives for magnetic data storage

Disk drive spindle motors require accurate speed control and highly efficient drive controllers. Small-volume and high-efficiency converters are of particular interest for portable data storage applications. Quasi-resonant voltage controllers are described in this paper and the experimental results are presented. In contrast to the conventional pulsewidth-modulated voltage controller, this technique reduces the switching loss and enables the controller to operate at very high frequencies. Three types of resonant converters are built and tested for the application. A comparison of performance in terms of losses and voltage regulation is given. Index Terms--Disk drives, reverse rotation, spindle motor, starting scheme, voltage controller.