摘要
针对三电平中点钳位型逆变器存在较大电压偏移问题,提出一种改进的控制中点电位平衡的方法,并采用磁链和转矩双闭环控制的三电平逆变器供电的异步电机直接转矩控制方案。首先,直接在坐标系下对转矩和磁链进行调节得到所需施加的电压空间矢量;其次,基于非正交的60坐标系,在内部扇区通过检测中点不平衡方向以及三相输出电流,采用相应的SVPWM调制顺序,在外部扇区采用合成虚拟矢量的调制方法;最后,仿真结果表明了该控制算法的可行性,异步电机响应迅速,转矩脉动较小,同时中点电位不平衡得到了有效地抑制。
In this paper,aimed at the neutral-point potential unbalance of the three-level neutral point clamped inverter,an improved new control scheme about neutral-point potential balance was proposed and double closed loop control of flux and torque was used for the direct torque control system of an induction machine fed by three-level inverter. Firstly,the reference space vector was obtained by adjusting flux and torque based on coordinate. Then,based on non-orthogonal 60 coordinate,the corresponding order of SVPWM was employed by the detection of neutral-point voltage ripple＇s direction and three-phase current in internal sector. The method of synthesizing virtual space vector was used in external sector. At last,the results verified the feasibility of the proposed scheme. The induction motor responded quickly and torque ripple smaller,with which the neutral-point voltage unbalance was restrained.
出处
《微电机》
2016年第7期62-67,共6页
Micromotors
关键词
三电平逆变器
异步电机
直接转矩控制
双闭环控制
中点电位平衡
three-level inverter
induction motor
direct torque control
double closed loop control
neu tral-point potential balance
