【作者】 王森；

【导师】 张炳义；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2014， 博士

【摘要】 无人机主推进永磁电动机（Main Propulsion Permanent-magnet Motor，简称MPPM）要求具有较高的力能密度（包括功率密度和转矩密度）。同时无人机的飞行工况复杂，分为地面滑跑、起飞爬升、巡航、降落和着陆五个阶段。电机在爬升阶段时力能密度最高，在巡航阶段初期时温升值最高。高力能密度及复杂工况给电机设计和分析带来新问题，本文围绕无人机主推进高力能密度永磁电动机的关键技术展开研究，主要内容如下：根据MPPM对体积和重量的要求以及热负荷达到普通电机5倍的特殊性，本文着重研究了超高力能密度永磁电动机设计方法。在理论上，研究了电机结构参数对电机力能密度影响，对比不同极数、极弧系数、永磁体厚度和电机尺寸对气隙磁密、交直轴电抗和齿槽转矩的影响。对MPPM磁路结构进行了优化设计，分析对比不同隔磁桥、转子外圆的不均匀气隙、永磁体位置对电机的气隙磁密、空载感应电势的影响，给出了MPPM基本优化设计方法。并研究了高频高磁密下MPPM铁心损耗计算方法，重点考虑局部磁滞回环对磁滞损耗的影响，引入设定局部磁滞环的损耗系数K min，给出高电磁负荷下铁心损耗修正系数计算公式。高力能密度将导致电机温升提高，温升将成为考核主推进电机的重要指标。为提高力能密度MPPM采用开启式结构，通风散热效果好，但冷却空气雷诺数超过10000，流体强紊流特点增加了温度场计算的复杂性。本文针对电动机开启式结构特点，根据流体力学及传热学理论，考虑了高频下的集肤效应对铜耗的影响，建立强风冷却条件下流固耦合物理模型与数学模型，研究了MPPM温度场给出主要固体部件及流体的温度分布，并分析主要部件温升随工况变化曲线。研究给出了不同热负荷状态下，不同爬升时间和爬升角度，MPPM温升特性，从理论和实践上，给出了无人机MPPM热负荷设计范围为30005500A2/cm·mm2，为主推进电动机热负荷设计提供理论参考。MPPM的超高力能密度，对机械强度和振动提出了更高的要求。本文基于弹性力学理论，建立了主要部件的机械强度计算模型，并分析了不同飞行工况下的应力分布。根据应力分析结构，研究了端盖支撑筋对机壳机械强度的影响，基于模态分析理论对MPPM进行振动特性分析，基于弹性矩阵理论对不同频率下的振型进行了分析。从系统的角度，考虑无人机实际运行中气流波动造成振动的频率，研究MPPM的振动频率和质量参与系数，给出避免发生共振的方法。成功研制MPPM样机，完成首飞试验测试。对样机进行了地面、风洞与飞行试验。样机性能指标：重量20kg，功率25kW，转矩100N·m，力能密度6.25kW·N·m/kg2，远远高于国内水平。飞行试验中温升最高值出现在巡航初期，机壳最高温升89.49K，铁心最高温升105.07K。对比分析MPPM各飞行工况下仿真结果、风洞试验数据和飞行试验数据，证明了理论分析的正确性。更多还原

【Abstract】 UAV Main Propulsion Permanent-magnet Motor (MPPM) requires high energy density(power and torque density), and the UAV flight condition is complex, divided into groundtaxiing, take-off and climb, cruise, descent and landing five stages. The energy density ofmotor is the highest in the climbing stage while the temperature of motor is the highest in theearly cruise. New problems of the motor design and analysis are appeared due to high energydensity and complex working condition. This doctoral thesis focuses on the key technology ofMPPM for UAV. The main contents are as follows:For MPPM, according to the requirements of volume and weight and the particularity ofheat load that is5times to heat load of ordinary motor, this doctoral thesis particularlyresearches the design method of ultra-high energy density permanent magnet motor. The effectof structural parameters on motor energy density is researched in theory. The different poles,pole arc coefficient, thickness of permanent magnet and motor size are compared to researchthe effect on air gap flux density, the d-axis and q-axis reactance and cogging torque. TheMPPM magnetic circuit structure is optimized. Different rib, non-uniform air gap duo to rotorout arc, length between permanent magnet and rotor inner diameter is analyzed to research theeffect on air gap flux density and EMF. The basic MPPM optimization design method is given.The core loss calculation method of MPPM is researched at high frequency and high fluxdensity, especially considering the impact of local hysteresis loop on hysteresis loss. Thehysteresis loss factor Kminfor each local loop is set according to the empirical formula, and thecalculation formula for correction coefficient of core loss is given under high electrical load.High energy density will cause the increase of motor temperature rise. The temperature risewill be an important indicator of assessment on main propulsion motor. MPPM uses openstructure to improve energy density, which has good ventilation; However, Reynolds numberof the cooling air is over10000, and the strong turbulence characteristics of fluid increasecomplexity for calculating temperature field. In this doctoral thesis, according to fluidmechanics and heat transfer theory, considering the effect of high frequency skin effect oncopper loss, the fluid solid coupling physical models and mathematical models to study theMPPM temperature field are established under strong wind cooling conditions for thecharacteristics of motor open architecture. The temperature distribution of main components and fluid is given, and the temperature rise of main components in different workingconditions is analyzed. The temperature rise characteristics of MPPM under different thermalload conditions, different climb time and climb angle are researched. The suitable heat loadrange is3000-5500A2/cm·mm2for MPPM of UAV, which provides theoretical reference fordesigning heat load of main propulsion motors.MPPM has characteristics of extra-high energy density, which asks a higher requirementfor mechanical strength and vibration. Based on elasticity theory, the calculation model ofmechanical strength for main components is established and the stress distribution of motorunder different flight conditions of UAV is analyzed. According to the stress analysis structure,the influence of motor cover support ribs on mechanical strength of motor house is analyzed.Based on the modal analysis theory, the vibration characteristic of rotor body is analyzed.Based on the elasticity matrix theory, modes at different frequencies are analyzed. Consideringthe vibration frequency caused by the flow fluctuations of actual operation of UAV, thevibration frequency and quality participation factor of MPPM are researched, and some waysto avoid the occurrence of resonance are given.The MPPM prototype was developed successfully and the first flight test was completed.The ground tests, wind tunnel tests and flight tests were performed for MPPM prototype.MPPM prototype performance indicators were: weight20kg, power25kW, torque100N·m,energy density6.25kW·N·m/kg2, which were much higher than the national level. The highesttemperature rise is appeared in the early cruise during flight test, and the maximumtemperature rise was89.49K while the maximum core temperature was105.07K. Thesimulation results, wind tunnel test data and flight test data of MPPM were compared amongeach flight conditions, which provided the correctness of theoretical analysis.更多还原