基于永磁电机相电流重构的冗余采样与驱动控制策略

Redundant Sampling and Drive Control Strategy Based on Phase Current Reconstruction of Permanent Magnet Motor

  • 摘要: 两种永磁同步电机相电流重构方法被讨论,分别是基于驱动器直流母线电流采样的三相电流重构和基于单相电流采样的二阶广义积分器(Second order generalized integrator,SOGI)三相电流重构。由于这两种方法都能够独立地为电机驱动控制提供三相电流反馈,因此提高了驱动系统电流反馈的可靠性。通过仿真和试验对两种重构方法的性能进行对比。研究发现,母线电流重构相电流的瞬态性能较好、响应快,但是由于开关时序影响,重构电流可以观察到显著噪声;相反,单相电流SOGI锁相环重构电流的稳态性能较好,相电流平滑稳定,但是瞬态性能较差,可以观察到明显的电流幅值变化滞后。因此,提出一种融合控制策略,综合直流母线电流采样和单相电流采样的二阶广义积分器三相电流重构方法的优势。通过动态权重调整机制,该策略能够根据不同运行状态,灵活地调整驱动控制器对两种电流重构反馈的依赖程度。通过仿真和试验验证,所提融合控制策略在不同工况下均表现出良好的性能,为电机驱动控制领域提供一种新方案。

     

    Abstract: A discussion of two methods for reconstructing the phase currents of permanent magnet synchronous motors is presented. These approaches are based on the sampling of driver DC bus currents and single-phase currents, respectively. The former is known as three-phase current reconstruction based on driver DC bus current sampling, while the latter is referred to as second-order generalized integrator(SOGI) three-phase current reconstruction based on single-phase current sampling. Since both methods are able to provide three-phase current feedback for motor drive control independently, the reliability of the current feedback of the drive system is improved. The performance of the two reconstruction methods is compared by simulation and experiment. It is found that the transient performance of bus current reconstructed phase current is better and the response is fast, but due to the effect of switching timing, the reconstructed current can be observed to be significantly noisy; on the contrary, the steady-state performance of single-phase current SOGI phase-locked loop reconstructed current is better, the phase current is smooth and stable, but the transient performance is poorer, and the obvious current amplitude change hysteresis can be observed. Therefore, a fusion control strategy that combines the advantages of the SOGI three-phase current reconstruction methods for DC bus current sampling and single-phase current sampling is proposed. Through a dynamic weight adjustment mechanism, the strategy is able to flexibly adjust the degree of dependence of the drive controller on the two current reconstruction feedbacks according to different operating states. The fusion control strategy is verified by simulation and experiment, and shows good performance under different operating conditions, providing a new scheme in the field of motor drive control.

     

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