Low cost inverter topologies for extended torque speed characteristics of spindle motor

This paper presents two low cost inverter topologies to drive a spindle motor at high speed with high starting torque with the help of bipolar starting and unipolar running algorithm. These two topologies have been realized with only eight switches, which are far less count as compared to other available topologies for driving a spindle motor. Both the topologies are used to achieve high starting torque with high speed with simple control. The operation of the brushless DC motor drive using the proposed novel topologies are presented discussed and compared. In this algorithm the changeover speed is estimated at which smooth changeover is possible from bipolar to unipolar. The proposed topologies have been simulated using MATLAB/Simulink and the results are presented. The proposed inverter topologies are best suited for low power drives.