【作者】 卜文绍；

【导师】 黄声华；

【作者基本信息】 华中科技大学 ， 电力电子与电力传动， 2007， 博士

【摘要】 无轴承电机突破了传统机械轴承支撑电机的运行理论范畴,是集旋转驱动和转子自悬浮功能为一体的新型磁悬浮电机。各种无轴承电机都有相同或相似的磁悬浮特性和规律,磁悬浮控制模型是实现无轴承电机可靠悬浮运转的基础。本文围绕无轴承电机的磁悬浮力产生机理,对具有圆筒式定子结构的二极悬浮控制四极无轴承电机的通用电感矩阵及电感系数解析模型、可控制磁悬浮力通用模型及磁悬浮解耦控制系统等进行了深入的理论分析和试验研究。以二极悬浮控制四极无轴承异步电机为例,考虑到转子偏心对气隙磁场分布的影响,解析了无轴承电机麦克斯韦磁悬浮控制机理。还对作用于感应型转子上的切向洛伦兹力衍生出的径向电磁力进行了解析研究,得出了洛伦兹力衍生出平均径向电磁力的基本条件。以凸极弧宽为“2ρ”弧度的凸极型转子结构无轴承电机为二极浮控四极无轴承电机的一般化结构模型,研究了转子偏心对无轴承电机内气隙磁场分布的影响。然后,基于无轴承电机气隙磁场分布规律,推导出了磁路不饱和情况下,二极悬浮控制四极无轴承电机的各个电感系数和电感矩阵的通用解析模型。该通用电感解析模型既适用于凸极型转子结构无轴承电机,又可适用于圆柱型转子结构无轴承电机,并针对具有圆柱型转子结构的无轴承异步电机进行了模型的实验验证。根据无轴承电机的通用电感模型,基于电磁场虚位移原理,推导出了无轴承电机的可控磁悬浮力通用模型。包括无轴承电机的旋转可控磁悬浮力通用模型和静止坐标系下的可控磁悬浮力通用模型等。并针对无轴承异步电机样机,进行了直流磁悬浮静力实验,验证了可控磁悬浮力模型的有效性。文中还认真分析了旋转可控磁悬浮力控制电流的频率特点,即:要产生同步速旋转可控磁悬浮力,需要在二极悬浮控制绕组中通入角频率为“0.5ω”的“半频”控制电流;要产生异步速旋转可控磁悬浮力,需要在二极悬浮控制绕组中通入角频率为“0.5(1+s)ω”的“近似半频”控制电流。基于三相无轴承异步电机可控磁悬浮力模型,设计了三相无轴承异步电机磁悬浮解耦控制系统。在对系统进行仿真试验分析之后,基于单TMS320LF2407A数字信号处理芯片设计了无轴承异步电机的硬软件控制系统实验平台,并实现了无轴承电机的稳定悬浮控制。仿真和实验结果表明,无轴承异步电机可控磁悬浮力模型具有良好的解耦性能,也从一个应用侧面验证了所推导出的通用可控磁悬浮力模型的有效性及合理性。最后,基于无轴承电机旋转可控磁悬浮力模型,研究了无轴承电机的周期性旋转惯性离心振动抑制技术和策略。试验结果验证了旋转可控磁悬浮力模型的有效性,并且验证了旋转磁悬浮力控制电流的半频特性。更多还原

【Abstract】 The bearingless motor has breached the theory category on running of conventional motor with mechanical bearing, and is a newly type of motor which integrates the function of revolving drive and that of rotor’s self-levitation. All kinds of bearingless motor have the same or similar magnetic rules and characteristics, and the control-model is the foundation of reliable self-levitation control for bearingless rotor. Surrounding the principle how the magnetic suspension force be produced, and aiming at 4-pole bearingless motor with 2-pole magnetic suspension windings and cylindrical stator, a series of universal models have been analyzed and derived in detail, including the universal analytical models on inductance coefficients and inductance matrixes, the universal model on controllable magnetic suspension force. The decoupling control system of magnetic suspension system has been constructed, and relevant experiments have been made.Taking the 4-pole induction type bearingless motor with 2-pole magnetic suspension windings as example, and taking the influence of rotor eccentricity on airgap magnetic field into account, the Maxwell magnetic suspension principle of bearingless motor are analyzed. The radial electromagnetic force derived from Lorenz force which drives the rotor is analyzed in detail also, and the fundamental conditions are derived. When the fundamental conditions are satisfied, the radial electromagnetic force would be derived from tangent Lorenz force.The paper has made 4-pole beaingless salient-pole motor with 2-pole magnetic suspension windings as the generalized bearingless model-motor, whose salient-pole arc-width equals to“2ρ”radians. Based on the generalized model-motor, the influence of rotor eccentricity on the distributing principle of airgap magnetic field has been analyzed firstly. After then, based the distributing principle of airgap magnetic field, the universal models on inductance coefficients and inductance matrixes of bearingless motor are analyzed and derived in detail. The universal models on inductance not only be applicable to those bearingless motors with salient-pole rotor, but also be applicable to bearingless motors with cylindrical rotor. The validity of universal inductance models are validated by parameter experiment of induction type bearingless motor.According to the universal inductance models, and based on the virtual displacement principle of electromagnetic field, the universal model on controllable magnetic suspension force of bearingless motor are analyzed and derived in detail. The set of universal models on magnetic suspension force include universal model on revolving magnetic suspension force and universal model on magnetic suspension force in stationary directions. In the paper, the stationary magnetic suspension force experiment has been made, and the validity of universal model on controllable magnetic suspension force has been validated. The frequency characteristic of control current which controls the revolving magnetic suspension force is analyzed also. To producing revolving controllable magnetic suspension force with synchronous speed, half-frequency control current should be injected into the 2-pole suspension windings. And to produce revolving controllable magnetic suspension force with asynchronous speed, the angle frequency of control current should be“0.5(1+s)”. Here,“s”is the difference ratio of the revolving speed of controllable magnetic suspension force relative to the synchronous speed of motor.The magnetic suspensions decoupling control system of three-phase bearingless induction motor has been designed based on the controllable magnetic suspension force model. After simulink simulation of decoupling control system, the experimental device on control system of bearingless induction motor are devised based on TMS320LF2407A CMOS chip, and the decoupling control experiment has been made. The simulation and experiment of decoupling control system have validated the decoupling characteristic of controllable magnetic suspension force model of bearingless induction motor, and the validity of the universal magnetic suspension force are validated in an applied example.At last, the periodic revolving inertia vibration and its control technology of bearingless motor are studied based on the controllable revolving magnetic suspension force model. The validity of revolving magnetic suspension force in controlling the periodic revolve-inertia vibration has been validated by the Simulation results and the half-frequency characteristics of control current has been validated also.更多还原