【目的】针对多相自励磁同步电机在中高速运行工况下单一谐波励磁效率受限的问题,提出一种基于改进遗传算法的多谐波协同励磁策略。该策略充分利用多相电机所具备的高控制自由度,在定子谐波电流总量受限的条件下提升转子励磁电流。【方法】首先分析十一相自励磁同步电机的谐波励磁机理,建立定子谐波电流与转子励磁电流之间的数学模型。在此基础上,将传统单一谐波励磁拓展为多谐波协同励磁,引入三次、五次、七次及九次谐波作为主要励磁分量。随后,以励磁电流最大化为目标,在总谐波电流有效值不变的约束下构建多谐波幅值分配优化模型,并采用具有自适应机制的改进遗传算法对各次谐波电流幅值比例进行全局优化。最后结合查表法实现基波与谐波电流的最优分配。【结果】通过有限元仿真与试验平台对所提方法进行验证。在相同总谐波电流有效值条件下,多谐波协同励磁策略相比传统单一谐波励磁可显著提升转子励磁电流,试验结果表明励磁电流提高约 11.5%,这与仿真结果一致,证实了所提优化方法的有效性。【结论】研究结果表明,基于改进遗传算法的多谐波协同励磁策略能够在不增加定子总谐波电流有效值的前提下有效提升多相自励磁同步电机的励磁能力。该策略充分利用了多相系统的控制自由度,为中高速范围内的高效励磁控制提供了一种有效解决方案。

[Objective] To address the limited excitation efficiency of single-harmonic excitation in multiphase self-excited synchronous machines under medium- and high-speed operating conditions, a multi-harmonic cooperative excitation strategy based on an improved genetic algorithm is proposed. This strategy fully utilizes the high control degrees of freedom of the multiphase machines and increases the rotor excitation current under the condition that the total stator harmonic current is limited. [Methods] First, the harmonic excitation mechanism of an eleven-phase self-excited synchronous machine was analyzed, and a mathematical model describing the relationship between stator harmonic currents and rotor excitation current was established. On this basis, the conventional single-harmonic excitation scheme was extended to a multi-harmonic cooperative excitation strategy, in which the third-, fifth-, seventh-, and ninth-order harmonics were introduced as the main excitation components. Subsequently, with the objective of maximizing the excitation current, a multi-harmonic amplitude allocation optimization model was constructed under the constraint of a constant total harmonic current effective value. An improved genetic algorithm with adaptive mechanisms was adopted to globally optimize the amplitude ratios of different harmonic currents. Finally, the optimal distribution of the fundamental and harmonic currents was achieved by combining with a lookup-table-based method. [Results] The proposed multi-harmonic excitation strategy was verified through finite element simulations and experimental platform. Under identical total harmonic current constraints, the optimized multi-harmonic excitation scheme exhibited superior excitation performance compared with the conventional single-harmonic excitation method. Experimental results demonstrate that the rotor excitation current was increased by approximately 11.5%, which was consistent with the simulation results and confirms the effectiveness of the proposed optimization approach. [Conclusion] The research results indicate that the proposed multi-harmonic cooperative excitation strategy based on an improved genetic algorithm can effectively enhance the excitation capability of the multiphase self-excited synchronous machines without increasing the total harmonic current. This strategy fully utilizes the control degrees of freedom of the multiphase systems, providing an effective solution for efficient excitation control in the medium-to-high speed range.

国家自然科学基金 (52307072); 稀土新材料技术创新中心支持项目(CXZX-D-202402-0013)