基于占空比调节的无刷直流电机直接转矩控制

Direct Torque Control with Duty Cycle Control Strategy for Brushless DC Motor

传统直接转矩控制(DTC)在每一个控制周期对电机施加一个不变的电压矢量,从而导致较大的转矩脉动,而且开关管的开关频率不固定。为减小转矩脉动同时使开关管的开关频率恒定从而提升系统的稳定性,将占空比调制技术引入到无刷直流电机(BLDCM)DTC系统当中,并研究了4种占空比生成方法对转矩脉动的抑制效果。由于引入了占空比调制技术,零电压矢量和非零电压矢量作用的时间随占空比的改变而改变,因此能够对转矩进行更精细的控制从而抑制转矩脉动。仿真和试验结果验证了所提方法的有效性。

For the traditional direct torque control （DTC） system of Brushless I）C Motors （ BLDCM）, the motor was imposed on one fixed voltage vector during a control cycle, which lead to great torque ripples and inconstant switching frequency. In order to suppress the torque ripples and keep the switching frequency constant so that the reliability of the system could be improved, the duty ratio control method was introduced into the DTC system of BLDCM and the effect of four duty ratio determination method for suppressing the torque ripples were studied. By using the duty ratio control method, the acting time of the active voltage vector and zero voltage vector during one control cycle were decided by the duty ratio, so the torque could be controlled more accurately and the torque ripples could be suppressed. The results of the simulation and experiments highlight the validation of the method proposed.