Single stage brushless DC motor drive with high input power factor for single phase applications

This paper proposes a single stage topology suitable for small to medium power systems with high inertia loads such as home appliances. This approach features a single controlled power stage which implements both conventional brushless DC motor speed control and a novel power factor correction strategy. This approach eliminates the Boost Unity Power Factor (UPF) stage and bulk electrolytic capacitor typically used for single phase applications. With an appropriate current modulation strategy, the input current can be shaped and high input power factor can be obtained. Design equations are derived, a comparison with the conventional two-stage approach is performed and simulation and experimental results are presented.