针对磁悬浮电动机柔性转子穿越一阶弯曲临界转速所面临的问题,提出综合多种控制器于一体的振动控制方法。为保证控制器设计的准确度,采用在线扫频技术验证磁轴承系统各环节建模的正确性。基于不完全微分PID控制器,设计固定中心频率的陷波器抑制转子二阶弯曲模态。根据等效控制系统的阻尼特性,设计相位补偿器增加转子在一阶弯曲模态共振点附近的正阻尼,抑制转子一阶弯曲模态。考虑到转子存在较大的二阶柔性不平衡质量,根据最小电流控制准则,在转子穿越一阶弯曲临界转速之后启用同频陷波器,消除功放同频电流,避免磁轴承控制量过大造成功放电压饱和。试验结果表明,所设计的综合控制器有效抑制了转子的一阶和二阶弯曲模态,且转子在一阶弯曲模态处的最大位移振幅仅为轴承单边保护间隙的5%;最终转子成功穿越一阶弯曲临界转速,并稳定运行在转速34 000 r/min。
In order to solve problems confronted when the magnetic suspended rotor pass through the first bending critical speed, an integrated vibration control method is presented. To ensure the accuracy of the controller design, the online sweeping technology is used to certify the model of every segment of the magnetic bearing system. Based on incomplete differential PID controller, a fixed central frequency notch filter is designed to suppress the second bending mode. According to damping characteristics of the equivalent control system, the phase compensator is used to suppress the first bending mode. Considering large second-order flexible unbalanced mass, a general notch filter is applied when the rotor has crossed over the first bending critical speed based on the minimum current control standard to make the power amplifier work in the smallest current state to avoid amplifier voltage saturation. Experimental results show that the integrated controller effectively suppress the first and second rotor bending mode, and the rotor successfully cross over the first bending critical speed. In additional, the maximum displacement amplitude in the first bending mode frequency of the rotor is 5% of the protection gap of the catched bearing, and finally the rotor stably operating above the rated speed 34 000 r/min.