3×3相永磁辅助同步磁阻电机两相开路故障容错控制策略

Fault-Tolerant Control Strategy for 3×3 Phase Permanent Magnet Assisted Synchronous Reluctance Motor with Two-Phase Failure

单逆变器驱动的3×3相永磁辅助同步磁阻电机系统具有低成本、高可靠性的优点。该文针对此系统的两相开路故障,提出一种各模块转矩重新分配的容错控制策略。当同一模块发生两相开路故障时,将该故障模块完全切除,通过增加非故障模块的电流来实现容错运行。对于不同模块同相位两相开路,通过分析故障后各模块的等效电路,获得两相静止坐标系下电流之间的关系,然后构造拉格朗日函数,以铜耗最小为目标,求解电流幅值的最优解,最终实现转矩的重新分配。当发生不同相位两相开路时,以故障模块输出最大平均转矩以及总的转矩脉动最小为目标,对各模块转矩进行重新分配。该方法通过增加正常模块转矩脉动来部分抵消故障模块产生的脉动,达到抑制输出转矩脉动的目的。实验结果验证了所提容错控制策略能有效降低故障后电机的转矩脉动,提高了控制系统的可靠性。

The 3×3-phase permanent magnet assisted synchronous reluctance motor(PMa-SynRM)driven by the mono-inverter has the advantages of low cost and high reliability.Besides,a fault-tolerant control strategy for torque redistribution of each module is proposed for the two-phase open-circuit fault of the control system.When the two-phase open-circuit fault occurs in the same module,the faulty module is completely removed,and the fault-tolerant operation is realized by increasing the current amplitude of the non-fault module.For the phase-aligned two-phase open circuit of different modules,the relationship between the currents in the static coordinate system can be obtained by analyzing the equivalent circuit of each module after the fault.Then,the Lagrange function is constructed to solve the optimal solution of the current amplitude with the minimum copper loss as the objective,and finally the torque redistribution is realized.When two-phase open circuit occurs in different phases,it is necessary to take the maximum average torque output of the faulty module and the minimum output torque pulsation as targets to redistribute the torque of each module.By this method,the torque ripple of the non-fault module will be increased to partially offset the ripple generated by the fault module,so as to suppress the output torque ripple.The experimental results verify that the proposed fault-tolerant control strategy can effectively reduce the torque ripple and improve the reliability of the control system.