An Improved Control Strategy Based on the Duty Ratio Modulation to Reduce the Torque Ripple in Direct Torque Control of BLDCM

摘要

In this paper, an improved control strategy (ICS) based on the duty ratio modulation, by properly matching the positive voltage vectors with the new zero voltage vectors (ZVVs), is proposed in direct torque control (DTC) of brushless DC motor (BLDCM). The traditional voltage switching table for the six switches of the converter is modified according to this strategy to minimize the torque ripple. The ICS has been proved to be easy to realize, fast in dynamic response, insensitive to system parameters and economical in hardware. The analysis on the calculation model and the experimental results show that the ICS is more effective than the traditional one in reducing the torque ripple.