A Torque Ripple Reduction Method of Small Inductance Brushless DC Motor Based on Three-level DC Converter

In order to make small inductance brushless DC motor drive circuit achieve better drive performance, DC-DC converter is chosen to be added in front of the three-phase inverter to reduce the torque ripple. This paper proposes a novel circuit topology adding three-level DC converter in front of the three-phase inverter. The former three-level DC converter is used for speed control and the three-phase inverter circuit is only used for commutation. The simulation model of brushless DC motor based on three-level DC converter is built. To be suitable for DC brushless motor drive circuit and achieve better drive performance three-level DC converter uses the common ground structure and the voltage-sharing control is adopted. Finally the simulation results show that three-level DC converter is suitable to be used in the small inductance brushless DC motor drive circuit and drive circuit with three-level DC converter shows better drive performance than with buck converter.