Novel resonant pole inverter for brushless DC motor drive system

The brushless dc motor (BDCM) has been widely used in industrial applications because of its low inertia, fast response, high power density, high reliability, and maintenance-free reputation. It is usually supplied by a hard-switching pulse width modulation inverter, which normally displays relative low efficiency since the power losses across the switching devices are high. In order to reduce the losses, many soft switching inverters have been designed. However, these inverters have such disadvantages as high device voltage stress, large dc. link voltage ripple, discrete pulse modulation, and complex control scheme. This paper introduces a novel resonant pole inverter, which is unique to a BDCM drive system, and is easy to implement. The inverter possesses the advantages of low switching power loss, low inductor power loss, low device voltage stress, and simple control scheme. The operation principle of the inverter is analyzed. Simulation and experimental results are proposed to verify the theoretical analysis.