基于占空比调节的无刷直流电机直接转矩控制方法

Direct Torque Control of BLDCM Based on Duty Cycle Control

传统的永磁无刷直流电机直接转矩控制系统通常在一个控制周期中采用全开或全关两种工作状态,从而导致了较大的相电流和转矩脉动。鉴于此,该文在无磁链观测条件下永磁无刷直流电机直接转矩控制方法的基础上引入了占空比的控制思想,并设计了一种基于占空比调节的永磁无刷直流电机直接转矩控制的方法。该方法分析了电磁转矩波动的原因,建立了一个精确的占空比的计算方法;结合能量平衡以及转矩误差限制,确定了占空比的取值范围。仿真和实验结果表明,新的方法能有效地减小相电流与转矩脉动,提高了直接转矩控制的稳定性。

The conventional brushless DC motor control system based on direct torque control （DTC） gener- ally has two types of working condition, full-open and full-closed, which often leads to major phase current and torque ripple. Accordingly, duty cycle control strategy was adopted on the basis of DTC in brushless DC motor control system and a DTC method for brushless DC motor with duty cycle control was proposed. Based on the analysis of electromagnetic torque ripple, a precise calculating method was invented and the reasona- ble span of duty ratio was computed by energy balance and torque error restraining. Simulation and experi- mental results show that the new DTC strategy can effectively reduce torque ripples and improve stability of DTC.