Drive for Unipolar BLDC Motor based on SEPIC Converter

Our suggestion is to employ a single ended primary inductance converter (SEPIC) as a front-end device to provide unipolar current to a permanent magnet brushless dc (BLDC) motor. In series with each phase, a switch is added. Their drive specs are a little easier to understand because all of the switches gate drives have ground references. Additionally, low voltage applications benefit from being able to increase the available input voltage to better control current. With the SEPIC converter sourced by an ac source, it is preferable to use the discontinuous conduction mode. At this operating mode the waveform of the line current is very close to that of the line voltage. We demonstrate that power factor is improved with reduced low order harmonics without the use of voltage and current sensors. The low cost and reduced number of components of the suggested topology makes it attractive for use in many types of variable speed drive applications. Using MATLAB/SIMULIK, the proposed topology is simulated and validated