基于三电平优化矢量的异步电机模型预测直接转矩控制  

Model predictive direct torque control of induction motor based on three level optimization vector

作　　者：林宏民 吴晓新[1] 乐胜康 宋文祥[1] LIN Hong-min;WU Xiao-xin;LE Sheng-kang;SONG Wen-xiang(School of Mechatronic Engineering and Automation,Shanghai University,Shanghai 200072,China)

机构地区：[1]上海大学机电工程与自动化学院,上海200072

出　　处：《电机与控制学报》2018年第8期65-74,共10页Electric Machines and Control

基　　金：国家自然科学基金(51377102);国家重大科学仪器设备开发专项资助项目(2012YQ15008703)

摘　　要：针对模型预测三电平直接转矩控制需对27个电压矢量进行价值函数优化评估,使得计算量过大而不利于实际应用的问题,提出一种基于三电平优化矢量选择器的异步电机模型预测控制方案,根据转矩和定子磁链的给定值得到期望的优化电压矢量,只需对优化电压矢量所在扇区的有限的4个矢量进行优化评估,有效降低了求解计算量。进一步地,为降低开关频率,在价值函数上加入对IGBT开关切换次数的约束,形成具有开关频率限制的模型预测控制策略,在兼顾转矩和磁链偏差的同时降低逆变器开关频率。针对三电平预测控制中的中点电压平衡问题,根据中点电压大小和电机电流方向,实现了中点电压平衡控制。仿真和实验结果验证了所提出控制方案的正确性和可行性。Aiming at the problem of model predictive direct torque control for the three-level inverter needs to optimize the cost functions of all 27 voltage vectors,which makes the calculation of optimization process too large for practical application.A model predictive control scheme for induction motor based on three level optimal vector selector was presented,in which the desired voltage vector was obtained according to the references of torque and stator flux.The method only needs to optimize 4 vectors in the sector of the optimal desired voltage vector,which can significantly reduce the computational complexity of the optimization process.In order to reduce the switching frequency,a constraint on the number of IGBT switching times was added to the cost function to make a model predictive control strategy with switching frequency constraint,which can reduce inverter switching frequency with retaining the torque and flux deviation.Aiming at the problem of neutral point voltage balance inthe three-level predictive control,the balance control of neutral point voltage is realized according to the value of mid-point voltage and the direction of motor current.Both the simulation and experimental results are presented to verify the validity and feasibility of the proposed control scheme.

关 键 词：异步电机 三电平逆变器 模型预测直接转矩控制 开关频率约束 中点电压平衡 

分 类 号：TM343[电气工程—电机]