Direct Torque Control of Brushless Direct Current Motor Based on Position Detect Algorithm of Counter Electromotive Force

The key problem for BLDCM to obtain high performance is to reduce the ripple of torque. Current hysteresis PWM used for BLDCM can reduces the ripple of current, but not torque because the nonlinear relation between current and torque. Direct torque control is put forward in 1980s. The merit of DTC is that the response of torque is fast, and the ripple of torque is reduced. In this paper, direct torque control of BLDCM based on the position detect algorithm of counter EMF is presented. The voltage vector select table is constructed based counter EMF. The simulation results indicate the effectiveness of the method.