【作者】 曹鑫；

【导师】 邓智泉；

【作者基本信息】 南京航空航天大学 ， 电机与电器， 2010， 博士

【摘要】 开关磁阻电机(SRM)由于其双凸极结构的简单坚固的优点,以及恶劣工况下的良好运行特性,引起了学界和业界的广泛关注。将磁悬浮技术中的无轴承技术引入SRM中,可充分发挥SRM的高速适应性。同时,通过对定、转子间不对称径向力的主动控制,有望改善SRM固有的振动和噪声问题。作为美国未来多电/全电飞机电源系统的首选方案,高速开关磁阻起动/发电机系统已引起各国学者的密切关注,而无轴承开关磁阻起动/发电机的研究也将为具有磁悬浮功能的未来多电/全电航空发动机的发展提供必要的技术储备。此外,无轴承技术的应用也为开关磁阻发电机(SRG)在分布式发电系统、不间断电源(UPS)和可再生能源发电的飞轮储能系统、以及电动/混合动力汽车等领域的应用创造了条件。针对起动/发电机系统的两项关键技术,本文主要研究无轴承开关磁阻电动机(BSRM)的实现方案和无轴承开关磁阻发电机(BSRG)的运行理论与实现。基于双绕组BSRM,分别研究其麦克斯韦应力法建模、双绕组的分配设计方法、以及平均转矩和径向悬浮力独立控制策略。首先,从麦克斯韦应力法角度建立瞬时转矩和径向悬浮力的数学公式,为电流控制算法的设计提供理论依据。该方法避免了电感矩阵推导的繁琐过程,同时考虑了电机的磁饱和问题,能够为电机的本体设计和运行特性的离线分析提供理论参考。其次,研究了两套绕组安匝数随悬浮力和转矩变化的基本规律,为两套绕组的分配提供设计依据。最后,提出了平均转矩和径向悬浮力的独立控制策略。该方法简化了电机驱动和悬浮的控制算法,避免了平均转矩和径向悬浮力的耦合控制,减小了转矩脉动。但是,双绕组无轴承电机为了实现磁悬浮功能,增加了一套悬浮绕组,这增加了电机设计和装配时的复杂性。为此,研究了BSRM的单绕组悬浮技术。在建立径向悬浮力模型的基础上,提出了电动悬浮控制策略,并通过实验实现了BSRM的单绕组悬浮运行。单绕组BSRM的研究丰富了无轴承电机的研究理论,为BSRM的应用提供了新途径。所提出的控制策略简单、易实现,有利于其更好地工业化应用。将磁悬浮功能与发电机技术相结合,提出了BSRG的全周期发电运行方式。“全周期”的概念是针对传统SRG的“后半周期”发电的概念提出的。在BSRG全周期发电运行时,发电绕组在整个导通周期内均能向负载输出电能,因而称之为“全周期发电”。在探析BSRG全周期发电运行的基本理论后,建立了其电感模型和径向悬浮力模型。同时,基于两套绕组的电压平衡方程组,推导了励磁电流和发电电流的分段解析式,分析了机电能量转换过程。基于径向悬浮力模型,提出了BSRG的悬浮力控制算法,该算法实现了输出电压和径向悬浮力的协调控制。最后,通过仿真和实验验证了BSRG全周期发电运行方式的可行性和控制方法的有效性,实现了BSRG在发电状态下的稳定悬浮。更多还原

【Abstract】 Due to its simple structure and resilience to harsh operating conditions, the switched reluctance machine (SRM) has caused extensive concern over the recent years. The introduction of bearingless technology could fully take advantage of the high-speed ability of SRM. Meanwhile, the active control, over the unbalanced radial force between stator and rotor poles, is suitable for avoiding the vibration and noise in SRM. As the preferred implementation of power system for the more/all electric aircraft in USA, the high-speed switched reluctance starter/generator system has drawn more attention by scholars of all nations. Accordingly, the study of bearingless switched reluctance starter/generator will provide a solution for the future more/all electric aeroengine with the function of magnetic levitation. Moreover, the bearingless technology enhances the application of the switched reluctance generator (SRG) in the distributed power generation system, UPS, magnetic flywheel storage system, and electric/hybrid-electric vehicles.To aim at these two key techonologies in the starter/generator system, this dissertation focuses on the control scheme of the bearingless switched reluctance motor (BSRM) and the theory and implementation of the bearingless switched reluctance generator (BSRG).Based on the dual-winding BSRM, the modeling using Maxwell Stress Tensor method, the distributing design of two sets of windings, and the independent control of the average torque and the levitation force are proposed, respectively. Firstly, Maxwell Stress Tensor method is adopted to derive the mathematical models of instantaneous torque and radial force that can be used to design the current control algorithm. The derivation avoids the sophisticated deduction of the inductance matrix and partly considers the magnetic saturation, which can be referenced for machine design and offline analysis for motor characteristics. Secondly, in dual-winding bearingless motors, another winding is added in the stator to achieve the levitation function; hence, how to distribute the two windings becomes the key consideration for the machine designer. Therefore, the two-winding ampere-turn distribution is proposed for the machine design. Thirdly, in conventional control scheme of BSRM, both of the torque and the radial force are determined by main-winding and radial-force-winding currents. The current algorithm is complex and requires more digital memory resources. Therefore, an independent control is proposed for the average torque and the radial force. This method avoids the coupled control between the torque and the radial force, and simplifies the control algorithm of rotation and levitation. A set of levitation winding is added in dual-winding bearingless motors, which complexes the machine design and assembly. Hence, chapter 4 studies the single-winding technology of BSRM. Based on the radial-force mathematical model, the levitation control scheme is proposed for single-winding BSRM. The experimental results are included to verify the proposed bearingless strategy. The study of single-winding BSRM expands the theory of bearingless motors and provides a new approach for the application of BSRM.With the magnetic levitation and the generator being integrated, the BSRG is developed which is operated in a full-period generating mode. The concept of full-period stems from the latter half-period generation in the conventional SRG. In full-period generators, the mechanical energy is also converted into the electrical energy in the excitation region, which is why it is called“full-period generation”. The theory of the BSRG is demonstrated based on the full-period generation. The inductance and radial-force models are also deduced. In addition, the excitation and generation currents are expressed in different regions via the winding-voltage equations. The flux-linkage-current curves are depicted in order to illustrate the energy conversion in the full-period generator. The radial-force control algorithm is proposed for the BSRG based on the derived radial-force model, which coordinately controls the output voltage and the levitation force. Finally, the proposed operation of BSRG is verified by simulation and experimental results.更多还原