【目的】永磁发电机气隙磁场不可调节,导致输出电压调节范围较小。为实现气隙磁场可调节,文章研究了一种切向聚磁型并联结构混合励磁直流发电机。【方法】搭建Maxwell 2D与Simplorer场路耦合模型,采用有限元仿真了其空载特性与空载气隙磁密,讨论了其滤波电路中相关元件的参数选取,计算了其外特性,分析了电枢反应气隙磁密与调整特性。【结果】仿真结果表明,外特性负载一定时,励磁电流从-12 A到0 A,端电压增加了3.02 V;励磁电流从0 A到12 A,端电压增加了24.66 V。电枢反应工况下,气隙磁密基波幅值、5P、7P谐波幅值分别降低了0.05 T、0.02 T、0.01 T,3P、9P谐波幅值升高了0.09 T、0.03 T,气隙磁密曲线呈现一半加强一半削弱趋势。【结论】空载特性反映了对该电机施加正励磁的效果优于负励磁,适合低速、大转矩场合,转速越高,输出电压越高。外特性曲线反映了在负励磁电流下,发电机相电压有效值变化较小;在正励磁电流下,发电机相电压有效值变化很大。调整特性中,若使得发电机端电压保持不变,在增加负载电流的同时须增加励磁电流。

[Objective] The air-gap magnetic field of permanent magnet generators is non-adjustable, resulting in a limited output voltage regulation range. To achieve an adjustable air-gap magnetic field, this paper studies a hybrid excitation DC generator with a tangential flux-concentrating parallel structure. [Methods] A Maxwell 2D and Simplorer field-circuit coupling model was built. The no-load characteristics and no-load air-gap flux density were simulated by finite element method. The parameter selection of related components in the filter circuit was discussed. The external characteristics were calculated, and the air-gap flux density and adjustment characteristics under armature reaction were analyzed. [Results] The simulation results showed that, under a constant external characteristic load, when the excitation current increased from -12 A to 0 A, the terminal voltage rose by 3.02 V. Further increasing the excitation current from 0 A to 12 A resulted in a terminal voltage increase of 24.66 V. Under armature reaction conditions, the amplitudes of the fundamental wave, 5P and 7P harmonics components of the air-gap flux density decreased by 0.05 T, 0.02 T, and 0.01 T, respectively, while the amplitudes of the 3P and 9P harmonics increased by 0.09 T and 0.03 T, respectively. The air-gap flux density curve exhibited a trend where one half was strengthened while the other half was weakened. [Conclusion] The no-load characteristics indicate that applying positive excitation to the generator is more effective than negative excitation, making it suitable for low-speed and high-torque applications. The output voltage increases with higher rotational speeds. The external characteristic curve shows that, under negative excitation current, the variation in the generator's phase voltage root mean square value is relatively small, whereas under positive excitation current, the variation is significantly larger. In the adjustment characteristics, to maintain a constant generator terminal voltage, the excitation current must be increased as the load current increases.