新型无轴承无刷直流电动机结构与模型研究

Configuration and model of innovative direct current motor without bearing and brush

目前研究的无轴承电机均是将电机和转子悬浮磁路合为一体,两个磁场的叠加一方面容易造成磁饱和,使电机的承载能力下降,影响电机的稳定悬浮;另一方面电磁转矩与径向悬浮力之间具有很强的非线性耦合,而实现解耦控制是非常复杂的。将无刷直流电机的优点与磁悬浮轴承的优点结合,提出一种六自由度可控的无轴承无刷直流电动机结构,通过研究其悬浮原理和运行原理,建立了转子偏心时的精确数学模型和PWM(脉宽调制)调速的精确数学模型,经仿真测试,表明了这种电机结构的合理性。主要特点是承载能力高且电磁转矩控制与径向悬浮力的控制相互独立,无需复杂的非线性解耦控制。

Now bearingless motors that are being studied are all to combine the magnetic field together with motor and suspension bearing. The two magnetic fields are mixed, on the one hand, magnetic saturation is easily caused to affect bearing capacity and steady suspension of motor; on the other hand, a very strong nonlinear coupling between electromagnetism torque and radial suspension force is generated, whereas, it is very complex to realize decoupling control. In combination with the advantages of magnetic suspension bearing and direct current（DC） motor without brush, an innovative six-freedom DC motor without bearing and brush was put forward.. Through studying its suspension principle, moving principle, the accurate mathematics model was established when rotor is eccentric and when PWM adjustment speed is used. Simulation results prove the reasonability of this kind of motor structure. The major characteristics of the motor are as follows： it has high bearing capacity, and the control between electromagnetism torque and radial suspension force is mutually independent, in no need of complex nonlinear decoupling control.