[关键词]
[摘要]
在异步电机的高性能控制方案中,为了降低开关损耗,采用优化脉宽调制(PWM)实现低开关频率下较小的电流谐波畸变。但在调制模式频繁切换时,优化PWM会产生电流和转矩冲击。因此,研究了将优化脉冲在线移位的闭环定子磁链轨迹跟踪控制方法,提出了由基于自控电机的降阶观测器与电机电流模型观测器组成的双观测器模型,实现了基波分量观测。结合电流谐波最小脉宽调制(CHMPWM)开关角,利用其重构参考磁链与实际磁链的差值,实现定子磁链轨迹跟踪。提出了无差拍下修正开关角小于2时的脉冲模式调整方案,消除了系统的动态调制误差,实现了低开关频率下异步电机的高性能控制。在开关频率为300 Hz以下的NPC型三电平逆变器上的仿真和试验证明了定子磁链轨迹跟踪控制策略的有效性。
[Key word]
[Abstract]
In the high-performance control scheme of the asynchronous motor, in order to reduce the switching loss, the optimized pulse width modulation (PWM) is used to achieve lower current harmonic distortion at low switching frequency. However, the optimized PWM will lead to current and torque shocks when the modulation mode is frequently switched. Therefore, a closed-loop stator flux trajectory tracking control method that shifts optimized pulses online is studied, and a dual observer model consisting of a reduced-order observer based on a self-controlled motor and a motor current model observer is proposed to achieve fundamental component observation. By combining the current harmonic minimum pulse width modulation (CHMPWM) switching angle, the difference between the reference flux and the real flux is reconstructed to achieve stator flux trajectory tracking. A pulse mode switching scheme is proposed when the corrected switching angle is less than 2 under the deadbeat, which eliminates the dynamic modulation error and realizes the high-performance control of the asynchronous motor at low switching frequency. The simulation and experiment on NPC type three-level inverter with switching frequency below 300 Hz prove the effectiveness of the stator flux trajectory tracking control strategy.
[中图分类号]
[基金项目]
国家自然科学基金(51377102);上海开放大学科研创新项目(XK2006);上海开放大学科研创新团队项目