混合励磁空芯补偿脉冲发电机技术研究

The project is about the research on the special problems and key technologies of a new kinetic energy high pulsed power source-hybrid excitation aircore compensated pulsed alternator(CPA). A hybrid excitation aircore CPA scheme is presented that the excitation sources of the CPA rely mainly on the permanent magnets excitation and while take electrical excitation as subsidiary role. The scheme can overcome some disadvantages of the single electrical excitation CPA, such as the requirement of higher eletrical excitation capacity, higher loss, lower efficiency and lower reliability. The high power brushes and sliprings can be omitted in the hybrid excitation aircore CPA and therefore the reliability can be increased. The adjustment flexibility of the electromagnetic field in the hybrid excitation aircore CPA is enhanced by the use of subsidiary electrical excitation. And one single hybrid excitation aircore CPA can discharge for different types of loads.The critical problem for the hybrid excitation aircore CPA is the possible demagnetization of permanent magnets during discharge.The demagnetization of permanent magnets is mainly caused by the transient strong demagnetization magnetic field, the transient thermal rise and the impact stress during the discharge to the pulsed loads, such as the railguns.The influencing factors of demagnetization and the corresponding protection solutions are studied in terms of the topology, design and optimization of magnetic circuit. The strong coupling of multi-physics in the hybrid excitation aircore CPA is studied. And the mathmatical model with considersing the complicated physics field in the hybrid excitation aircore CPA is built, on which the operation action simulation of the whole discharge system is based. The optimization design methods are presented.The breakthrough of key technologies and the solution bottleneck problems are fundamental for the theroretical research and manufacturing of the prototype of CPA.

本项目针对惯性储能式高功率脉冲电源-电磁式补偿脉冲发电机-电励磁容量高、损耗大、效率低、可靠性低的缺点，对以永磁体励磁为主，电励磁为辅的混合励磁空芯补偿脉冲发电机的特殊问题和关键技术进行深入研究。该方案无需使用电刷和滑环，可提高系统可靠性，同时利用辅助的电励磁可从电机拓扑结构角度实现电机内部磁场的快速灵活调节，增强单一脉冲电源驱动不同放电负载的匹配能力。在研究中，存在的瓶颈问题是永磁体在强脉冲磁场、瞬时温升以及冲击应力作用下可能发生的失磁问题。因此，从拓扑结构、磁路设计和优化出发，研究混合励磁空芯补偿脉冲发电机内部的多物理场耦合问题，研究放电时影响永磁体失磁的各种因素和相应的保护方法，同时，建立考虑电机内部物理环境的混合励磁空芯补偿脉冲发电机数学模型，准确模拟放电系统的动态运行行为，对阐明电机本体同放电系统性能之间的关系，给出该特种电机优化设计方法，对突破补偿脉冲发电机技术瓶颈具有意义。

本项目提出了一种基于Halbach结构的混合励磁空芯补偿脉冲发电机，并对其设计方法和关键技术进行了深入研究。.给出了混合励磁空芯脉冲发电机新型拓扑结构，从关键参数计算和电机瞬时工作特点角度，给出了混合励磁脉冲发电机的特殊设计方法和设计流程；建立了混合励磁空芯CPA的电磁场、温度场、应力场模型，针对脉冲发电机的瞬时工作特点，从电磁-温度、电磁-应力多物理场角度进行了仿真研究，研究多物理场之间的影响规律，保证了电机设计的准确性；评估了电磁场、温度场、应力场对永磁体的退磁风险，研究了补偿筒对于永磁体抗退磁的保护作用，掌握了脉冲发电机动态工作过程中电机内部磁场的变化，评估了永磁体在脉冲发电机不同放电时刻的退磁风险，对永磁体去磁因素进行了系统分析，并给出了抗去磁的解决方案；建立了考虑电机内部多物理场耦合的混合励磁空芯CPA的数学模型，完成系统放电运行行为的联合仿真，给出了脉冲发电机输出电压电流和轨道炮的发射速度曲线和加速度曲线，更加准确的反应了脉冲发电机驱动非线性负载的实时过程；完善了优化设计方案，给出了混合励磁空芯脉冲发电机样机方案。.本项目给出了混合励磁空芯CPA的优化拓扑结构，给出了混合励磁空芯CPA多物理场耦合的内在规律，提出了混合励磁空芯CPA电机的基本设计方法和优化原则，给出了混合励磁空芯CPA中永磁体去磁因素的系统分析和抗去磁的解决方案。.本项目将混合励磁的概念引入到脉冲发电机的研究中，利用Halbach结构单边聚磁特性，提出了转子空芯的混合励磁脉冲发电机拓扑结构，降低了转子的质量，提高了转子的储能密度。拓宽了脉冲发电机的研究拓扑，增强了电机的可靠性和快速调节能力，提升单台电机驱动不同负载的能力，同时拓宽了脉冲发电机所能驱动负载的领域。所提出的基于Halbach永磁体阵列的混合励磁脉冲发电机的新型拓扑结构，实现混合励磁脉冲发电机的空芯方案，降低了转子质量，提高了转子转速，进而提高了电机的储能密度和功率密度，对加快脉冲发电机的应用具有推动作用。