碟式斯特林热电机组中磁场调制复合直线电机研究

A Linear Magnetic Field Modulation Permanent Magnet Machine for Dish Stirling Generator

直线发电机是斯特林热电机组的核心部件,为改进现有太阳能碟式斯特林发电机存在的功率密度小、铁磁材料利用率低等缺点,提出复合永磁直线发电机设计方案。由于磁场调制作用,在电机动子低速运动的情况下,在定子侧仍然可以得到幅值和频率相对较高的感应电动势。该电机整体采用平板式拓扑结构,外定子与磁场调制变速模块以平行并列结构同轴集成,可以降低加工难度。高速和低速动子永磁体均采用Halbach充磁方式并形成聚磁回路,在提高电机电动势基波幅值的同时降低谐波含量。另外,在高速动子侧引入阻尼环,有效抑制斯特林机因推力波动造成的机械振荡问题。通过建立电机等效磁路模型,分析电机在不同位移点的磁动势和磁导函数,为参数优化设计提供依据。根据设计方案制造了样机,实验测试与计算结果基本一致,验证了设计方案的正确性。

Linear generator is the core component of Stirling thermal generator set. In order to improve the disadvantages of existing solar energy dish Stirling generator,such as low power density and low utilization of ferromagnetic materials, the design scheme of composite permanent magnet linear generator was proposed. Due to the effect of magnetic field modulation, the induced electromotive force with relatively high amplitude and frequency can still be obtained at the stator side when the motor moves at low speed. The whole motor adopts flat topology structure, and the outer stator and magnetic field modulation variable speed module were integrated in parallel and coaxial, which could reduce the machining difficulty. The Halbach magnetization method was adopted in both high speed and low speed speed mover permanent magnets to form magnetic focusing loops, which could improve the fundamental amplitude of EMF and reduce the harmonic content. At the same time, the damping winding was introduced into the high-speed mover side to effectively suppress the mechanical oscillation caused by the thrust fluctuation of the Stirling machine. By establishing the equivalent magnetic circuit model of the motor, the magnetomotive force and permeance function of the motor at different displacement points were analyzed, which provided the basis for parameter optimization design. According to the design scheme, the prototype was manufactured, and the experimental results were basically consistent with the calculation results, which verified the correctness of the design scheme.