基于I-ω法磁场辨识的无轴承异步电动机矢量控制

集旋转与悬浮于一体的无轴承异步电动机是一个非常复杂的非线性系统,电磁转矩与径向悬浮力的非线性解耦是实现电机稳定悬浮运行的基础.气隙磁场定向控制算法复杂,且没有实现两者的动态解耦.提出了基于转矩绕组转子磁场定向控制算法,径向悬浮控制所需的气隙磁场通过I-ω实时辨识.仿真结果表明,电磁转矩与径向悬浮力实现完全解耦,验证了所提方案的有效性.     

A method of determining the advanced angle of square-wave currentsin a bearingless switched reluctance motor

Bearingless switched reluctance motors, which can control rotor radial positions with magnetic force, have been proposed. These motors have combined the characteristics of switched reluctance motors and magnetic bearings. This paper proposes a method of determining the advanced angle of square-wave currents in a bearingless switched reluctance motor. Under any torque condition, from no load to full load, stable operation is realized by controlling the advanced angle of square-wave currents with the proposed method. It is shown experimentally that the proposed method is effective in realizing stable operation     

Radial force and torque of a bearingless switched reluctance motor operating in a region of magnetic saturation

Bearingless switched reluctance motors, which can control rotor radial positions with magnetic force, have been proposed. These motors are characterized by integration of switched reluctance motors and magnetic bearings. It is essential for a control system to consider magnetic saturation in real time in order to realize stable operation at a full torque load. Thus, this paper proposes a method for fast calculation of radial force and torque of a bearingless switched reluctance motor operating in a region of magnetic saturation. It is shown experimentally that the proposed method is effective in calculating the radial force and the torque under conditions of magnetic saturation.     

Torque and suspension force in a bearingless switched reluctance motor

Bearingless switched reluctance motors, which can control rotor radial positions with magnetic force, have been proposed. The bearingless switched reluctance motors are characterized by integration of switched reluctance motors and magnetic bearings. These motors have two kinds of stator windings composed of motor main windings and suspension windings in the same stator in order to produce suspension force that can realize rotor shaft suspension without mechanical contacts or lubrication. For successful stable operation, accurate theoretical formulas of instantaneous torque and suspension force are necessary to a rotational speed controller and a rotor radial position controller. This paper derives the theoretical formulas of the instantaneous torque and the suspension force from an assumption of simple permeance distribution. This derivation process makes an assumption that fringing fluxes are distributed on elliptical lines. It is shown with experimental results that the derived theoretical formulas are very accurate in terms of practical application. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(2): 72–82, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20157     

An air-gap-flux-oriented vector controller for stable operation ofbearingless induction motors

A bearingless induction machine has combined characteristics of an induction motor and magnetic bearings. It is known that the magnetic suspension of the rotor becomes unstable at overload operation, particularly in transient conditions. A novel air-gap-flux-oriented vector control scheme has been proposed to operate the bearingless induction motor during the high torque acceleration period. It has been found that there is an optimal flux orientation for complete decoupling in radial force generation. Test results in a laboratory bearingless induction motor validates the performance efficacy of proposed controller at overload conditions     

无轴承永磁同步电机的转子磁场定向控制研究

无轴承永磁同步电机由于功率密度大、转矩脉动低等优良特性受到了高度重视。文中针对一类表面贴装式无轴承永磁同步电机，详细推导出径向悬浮力表达式，建立了准确的数学模型。针对电磁转矩和径向悬浮力之间耦合的特点，采用了基于转子磁场定向的控制策略来实现这类无轴承永磁同步电机的非线性解耦控制。实验证明了该控制算法的有效性。该控制算法对插入式转子结构和内装式转子结构的无轴承永磁同步电机的控制系统设计具有一定的借鉴作用。     

Characteristics of a permanent magnet type bearingless motor

Super high-speed and high-power electric machines are required for turbomolecular pumps and spindle drives. High rotational speed and high power drives can be achieved with bearingless motors. In this paper, a bearingless motor with the principles of permanent magnet type synchronous motors is proposed. High power factor and high efficiency can be expected in permanent magnet type bearingless motors. The proposed bearingless motor is a 4 pole permanent magnet synchronous motor, in which additional 2-pole windings are wound together with 4-pole motor windings in stator slots. With currents of 2-pole windings, radial magnetic forces are produced to support a rotor shaft. Principles of radial force production of surface-mounted permanent magnet bearingless motors are analyzed mathematically. It was found that radial forces are efficiently produced by employing thin permanent magnets on the surface of rotor iron core. A test machine was built in order to measure inductance functions as well as relationships between voltages and currents     

新型交替极无轴承永磁电机的原理与实现

传统永磁型无轴承电机悬浮力和转矩控制存在耦合，该文对一种新型交替极转子结构的无轴承永磁电机的磁悬浮原理进行了深入分析和数学建模，指出该类型电机所具有的独特的悬浮控制和转矩控制解耦的特点，并构建了无轴承交替极永磁电机的实时控制系统。实验结果表明实现了该新型无轴承永磁电机的动、静态稳定悬浮，验证了悬浮与转矩控制解耦的特性。     

Analysis and characteristics of a permanent magnet-type bearingless motor

Super-high-speed and high-power electric machines are required for turbomolecular pumps and spindle drives. High rotational speed and high-power drives can be achieved with bearingless motors. In this paper, a bearingless motor with principles of permanent magnet-type synchronous motors is proposed. High-power factor and high efficiency can be expected in permanent magnet-type bearingless motors. The proposed bearingless motor is a 4-pole permanent magnet synchronous motor, in which additional 2-pole windings are wound together with 4-pole motor windings in stator slots. With currents of 2-pole windings, radial magnetic forces are produced to support a rotor shaft. Principles of radial force production of surface-mounted permanent magnet bearingless motors are analyzed mathematically. The relationships between radial forces and the permanent magnet thickness were derived. From these relationships, the optimal permanent magnet thickness to produce radial forces efficiently is found. A test machine was built to confirm the relationships of radial forces, currents and voltages.     

Radial Force Analytic Modeling for a Novel Bearingless Switched Reluctance Motor When Considering Rotor Eccentricity

Abstract—Analytic modeling of radial forces is proposed for the novel bearingless switched reluctance motor, where the rotor eccentricity is taken into account. The novel bearingless switched reluctance motor's model is never disclosed, even though there are many advantages, such as fewer suspension windings and simpler control circuit and algorithm, when compared to the conventional bearingless switched reluctance motor. The analytic model of radial forces is very important to achieve this new bearingless switched reluctance motor's suspension control. The rotor eccentricity is a key cause to affect the radial forces. This article calculates the air-gap permeances through considering rotor eccentricity. The self-inductance and mutual-inductance expressions of the motor torque windings and the suspension windings are derived by using the magnetic equivalent circuit method. The derived radial force model discloses the effects of winding currents, rotor position angle, and rotor eccentricity displacement. The finite-element analysis based results verify the built model.     

无轴承永磁同步电机控制系统设计与仿真

无轴承永磁同步电机是自身具有磁悬浮轴承功能的新型特种电机，是一个复杂的强耦合的非线性系统，建立无轴承永磁同步电机径向悬浮力和电机数学模型，是设计无轴承永磁同步电机控制系统的前提，实现其径向悬浮力和电磁转矩之间的解耦控制是电机稳定运行的基本条件。该文在介绍无轴承永磁同步电机径向悬浮力产生原理的基础上，推导了径向悬浮力和电机数学模型，采用基于转子磁场定向控制策略设计了无轴承永磁同步电机矢量控制系统，利用Matlab的Simulink工具箱构建了矢量控制系统，对无轴承永磁同步电机的转速、转矩及转子起浮性能进行了仿真。仿真结果表明控制系统不仅可以实现转子稳定悬浮，而且电机具有良好的动态性能。     

计及偏心及洛仑兹力的永磁型无轴承电机建模与控制研究

对转子偏心情况下永磁型无轴承电机中2种磁悬浮力的产生机制进行了深入的理论分析和数学建模；特別揭示了转子偏心、转矩绕组磁场对悬浮力控制及悬浮绕组磁场对转矩控制的耦合影响；提出一种实用的悬浮力及转矩控制方案，并通过在一台表面贴装无轴承永磁同步电动机上进行的实验验证了其有效性和实用性。实验结果表明考虑转子偏心和洛仑兹力的影响有效的提高了无轴承电机悬浮运行时的稳态精度和动态响应速度，极大的拓宽了其应用领域。     

基于气隙磁场定向的无轴承异步电机非线性解耦控制

无轴承异步电机是一个强耦合的非线性复杂系统 ,实现其电磁转矩和径向悬浮力之间的解耦控制是该电机稳定运行的前提。本文在研究电机磁悬浮机理的基础上 ,利用电枢绕组气隙磁场定向控制来实现两者之间的动态解耦控制。实验证明该控制算法不仅能实现电机稳定的悬浮 ,而且使电机具有良好的调速性能     

宽转子无轴承开关磁阻电机的转子极形优化

为了解决宽转子无轴承开关磁阻电机由于开关型供电方式以及双凸极铁心结构在运行过程中容易导致转矩脉动很大的问题,本文对其转子极结构进行改进,提出在转子极两侧开槽的优化设计方案。旨在通过增大开槽处的气隙磁阻,提高用于产生转矩的切向分量的气隙磁密,从而降低转矩脉动。对所开槽进行参数化处理,使用控制变量法分析各开槽参数对转矩性能的影响,以性能指标最优为目标确定开槽参数。利用场路耦合的方法将电机有限元分析模型和直接瞬时转矩控制电路模型结合起来,实现电机系统的动态运行。仿真结果表明转子极开槽后能够有效降低宽转子无轴承开关磁阻电机的转矩脉动,提升平均转矩,并且对径向悬浮力的影响很小。     

磁悬浮无轴承异步电动机仿真

阐述了磁悬浮无轴承电机的基本状况，分析了磁悬浮无轴承异步电动机悬浮力产生的机理，按照气隙磁场定向控制设计了控制系统，将磁悬浮无轴承异步电动机等效成两台普通电机一转矩电机和悬浮力电机，建立了仿真分析模型，并进行了整个电机系统的仿真。     

磁悬浮无轴承电机的解耦控制

无轴承电机是利用磁悬浮轴承和电机结构的相似性,将产生磁悬浮力的磁悬浮轴承绕组置入电机定子,省去了专门的磁悬浮轴承;通过对转矩绕组和悬浮力绕组的解耦控制,使电机转子同时具有产生转矩和自悬浮的功能。无轴承电机能够实现高速、无摩擦等优良性能,是当前研究的热点之一。无轴承电机的解耦控制是控制系统设计的关键。论文介绍了目前无轴承电机解耦控制的基本原理和方法,并进行了对比和分析,可针对不同电机来设计控制系统。     

一种新型混合转子结构无轴承电动机磁悬浮力的矢量控制

无轴承电机具有无机械磨损和噪声等优点，其转子旋转和悬浮的电磁转矩和磁悬浮力皆由电机本身产生。在对不同转子结构转矩和磁悬浮力进行有限元对比分析的基础上，该文提出了一种兼有永磁式和感应式转子共同优点的新型混合转子结构。该电机不仅能产生大的电磁转矩和磁悬浮力，而且提供了通过电流矢量定向实现悬浮力解耦控制的途径。基于数字信号处理器DSP(TMS320C32)和复杂可编程逻辑芯片CPLD(Xilinx)，构建了混合转子无轴承电机的控制系统，实现了悬浮力矢量控制策略。试验结果表明该文所提出的新型无轴承电机的设计与控制策略是可行的。     

永磁无刷直流电动机场路耦合运动时步有限元分析

提出一种适用于永磁无刷直流电动机的场路耦合运动时步有限元分析方法，解决了电机在非正弦供电时的场路耦合分析问题。电路中考虑了开关元件换流重叠过程和绕组中点的电位波动。给出了控制电路与电磁场方程耦合的时步有限元单元分析方法，采用改进的有限元运动边界处理方法--插值运动边界法解决转子运动问题。应用上述模型对1台无刷直流电动机的进行分析，计算结果和样机的实测波形吻合。该方法也适用于其他非正弦供电电机的场路耦合有限元分析。     

Improved analysis of a bearingless switched reluctance motor

Bearingless switched reluctance motors, which can control rotor radial positions with magnetic force, have been proposed. Bearingless switched reluctance motors have combined characteristics of switched reluctance motors and magnetic bearings. Production of radial force for rotor shaft magnetic suspension is explained with differential stator windings. Mathematical relations between motor currents and radial force are derived by considering cross coupling and fringing fluxes. Theoretical relationships are verified with experimental results at partial overlap positions     

新型混合励磁磁悬浮开关磁阻电机基础研究

为了实现磁悬浮开关磁阻电机(BSRM)转矩和悬浮力的自然解耦,提出了一种新型混合励磁磁悬浮开关磁阻电机(HEBSRM)。新型HEBSRM由12/14极BSRM、环形永磁体和径向磁轴承三部分组成。12/14极BSRM的转矩极和悬浮极之间嵌有隔磁环,使转矩磁通路径完全独立于悬浮磁通路径,从而在结构上实现转矩与悬浮力解耦。此外,详细推导了电机径向悬浮力的数学模型,并且通过有限元分析验证了新型HEBSRM结构的合理性。