基于特征值规范型矩阵的内嵌式永磁同步电机低载波比建模方法

Modeling of Interior PMSM Based on Normal Canonical Form Under Low Carrier Ratio

受到功率器件开关频率的限制,大容量或高转速电机的驱动系统通常要求低载波比运行。内嵌式永磁同步电机dq轴参数不对称,数学模型复杂,在低载波比下,电流环反馈解耦不彻底,控制器优化困难。因此,文中提出一种基于特征值规范型矩阵的建模方法,通过非奇异线性变换,将非对称系统等价转化为对称系统,并利用复矢量建模简化为单输入单输出系统,便于控制器优化设计。此外,基于特征值规范型建模方法,推导出适用于非对称系统的复数PI控制器。仿真与实验结果表明,所提出的建模方法不会引入额外的建模误差。相较于经典PI控制器,所推导的复数PI控制器可实现dq轴解耦控制,动态响应快,相位裕度大幅提升。

Since the switching frequency of power devices is limited,the drive systems for large capacity or high speed motors usually require low carrier ratio operation.For interior permanent magnet synchronous motor(IPMSM),its asymmetric dq-axis parameters complicate the mathematic model.Furthermore,under low carrier ratio,the current feedback decoupling is incomplete,perplexing the controller optimization.Therefore,a modeling method based on normal canonical form is proposed.Though non-singular linear transformation,the asymmetric system is equivalently transformed into symmetric system,which is further simplified as a single-input single-output system through complex vector modeling and thus facilitates controller optimization.Furthermore,the complex PI controller applicable for asymmetric system is derived based on the proposed normal canonical form modeling method.The simulation and experimental results demonstrate that the proposed modeling method does not introduce extra errors and the derived complex PI controller achieves dq-axis decoupling control,faster dynamic response and much larger phase margin compared with standard PI controller.