【作者】 马长山；

【导师】 周波；

【作者基本信息】 南京航空航天大学 ， 电力电子与电力传动， 2007， 博士

【摘要】 永磁式双凸极电机既有开关磁阻电机的结构简单、可靠性高等优点,又有永磁无刷电机高的功率重量比、损耗小等优点,因此受到人们越来越多的关注。本文主要致力于永磁式双凸极电机新型驱动系统的研究。在电机本体有限元计算的基础上,分析转矩脉动的形成机理,研究电机开通关断角与转矩脉动的关系、转矩控制技术、速度调节器的鲁棒性控制以及位置信号的故障诊断与容错控制等。针对6/4极永磁式双凸极电机,采用ANSOFT公司的Maxwell软件对电机内磁场进行分析计算,研究了电机的磁场分布、气隙磁密、绕组电感、绕组磁链、磁阻转矩和永磁转矩等基本静态特性。模拟了实际电流的换相过程,给出了电机带载后的磁场分布和参数变化规律。还对6/4极电励磁双凸极电机和12/8极永磁式双凸极电机进行空载有限元分析,说明了换相前后磁链变化率基本相同这一特征是永磁式双凸极电机的共性。在有限元计算结果的基础上,建立了基于MATLAB/SIMULINK的非线性电感和磁链的驱动系统仿真模型,为研究永磁式双凸极电机新型驱动系统奠定了基础。研究永磁式双凸极电机转矩脉动的形成机理,从换相脉动和稳态脉动角度出发,分析换相脉动的产生原因,给出了换相脉动是电机主要转矩脉动的结论。为减小换相时三相同时导通或关断引起的换相脉动,提出了新型开通关断角控制策略,提高了换相期间输出转矩,减小了转矩脉动。同时结合理论分析,研究了换向相电流比大小对转矩脉动的影响,推导出换向相的最优电流比,减小系统设计容量,并通过仿真和实验验证了理论分析的正确性。通过对永磁式双凸极电机磁阻转矩和永磁转矩的分析,得出永磁转矩是电机的主要输出转矩,以及永磁转矩脉动是电机主要脉动的依据。由于永磁式双凸极电机的电流与转矩之间呈较严重的非线性,为进一步减小转矩脉动,以及适合车载驱动系统,提出了转矩内环的控制策略,并构造了转矩观测器。由于电机无中线,为得到转矩观测器所需的相电压,推导了线电压到相电压的转换公式,并设计了二阶滤波器对线电压进行滤波,同时利用过采样和数字滤波的方法,提高了电压的采样精度,快速准确计算三相相电压,进而实时计算电机转矩。仿真和实验表明,与电流控制相比,转矩控制时转矩脉动小,低速时转速波动较小。由于电动机长时间运行后磁饱和、绕组温度变化等内部参数改变,以及外部扰动对电机运行的影响,导致系统的控制精度降低和控制性能变坏。为减小参数变化对系统性能的影响,提高系统的抗干扰性能,对具有强鲁棒性的滑模变结构控制进行理论分析。建立了系统状态方程,推导了滑模控制输出量与电磁转矩的关系,根据等效控制理论,利用一阶滤波器减小滑模控制抖振。引入了前馈控制,首次在双凸极电机上设计了基于新型比例滑模控制的速度调节器,减小了一阶滤波器对系统动态性能的影响。根据控制系统动态响应要求,给出了前馈控制增益和滑模控制参数的调节方法。为提高驱动系统的可靠性,开展了永磁式双凸极电机位置信号的故障诊断与容错控制研究。分析了位置信号故障后电机电流与转矩的变化规律、故障前后位置信号电平的变化以及故障瞬间可能形成的边沿对系统触发中断的影响。根据三相位置信号的特征及边沿触发模式,提出了位置信号的故障诊断和容错控制方法。通过故障模拟实验,验证了故障诊断和故障容错控制的有效性,系统过渡时间短,且实现方便、实时性好。以数字信号处理器DSP和可编程逻辑器件CPLD为核心,智能功率模块IPM为逆变器,设计了永磁式双凸极电机新型驱动系统,为实验研究提供可靠的平台。更多还原

【Abstract】 Doubly salient permanent magnet (DSPM) motor has been researched by many scholars due to incorporate the merits of both switched reluctance motor and PM brushless motor. In this dissertation, a novel driving system for DSPM motor is developed. The main topics include finite element analysis (FEA), the mechanism of torque ripples, the relationship between turn-on angle & turn-off angle and torque ripple, technology of torque control, robustness of speed loop, and fault diagnosis and fault tolerant of position signals.The static characteristics of 6/4-pole DSPM motor is given through two-dimensional FEA software Maxwell of ANSOFT corporation, including magnetic field distribution, winding inductances, winding flux linkages, reluctance torque and permanent magnet(PM) torque and so on. The magnetic field distribution and parametric variation of DSPM motor is analyzed after load through simulated real currents. The winding inductances and winding flux linkages for 6/4-pole doubly salient electro-magnet motor and 12/8-pole DSPM motor at no load is also given in order to describe the common character of nearly equal flux slope in former and back of commutation for DSPM motor. The nonlinear simulation model of driving system for DSPM motor based on MATLAB/SIMULINK is built according to the data of flux and induction calculated by Maxwell software.The cause of torque ripples is analyzed in detail from the view of commutation ripple and steady ripple, and a conclusion that commutation ripple is the main ripple for DSPM motor is given. A novel optimal control strategy of turn-on angle and turn-off angle is proposed in order to reduce commutation torque ripple. The relationship between the current ratio of commutation phase and torque ripple is analyzed, and the optimal current ratio is deduced. The validity of the novel control strategy is verified by simulation and experiment.It is concluded from the contrast analysis of reluctance torque and PM torque that PM torque is the main torque and the main ripple is PM torque ripple. The torque control strategy is proposed in order to further decrease the torque ripple and be fit for electric vehicle. And the torque observer is structured. Also the transition formula from line voltage to phase voltage is given and a second-order filter is designed for line voltage.More and More attentions have been paid to robustness study due to magnetic field saturation and winding resistance variation after long run, which will bring precision and performance of control system low. The sliding model control (SMC) with strong robustness is employed to decrease the influence of parameters variation. State equations are established and the relationship between the output of SMC and torque is deduced. At the same time first-order filter is employed to reduce the chattering, but the dynamic characteristic of system will be weakened. Thus a speed regulator with good dynamic characteristic is designed based on novel SMC combined feed forward control.Position sensors are the key of exact commutation for brushless motor, hence it is very necessary to study fault diagnosis and fault tolerant control of position signals. The running status after fault is described, including current, torque, level of position signal. A method of fault diagnosis through detecting the level value of three phase’s position signals is proposed. Also the method of fault tolerant after one-phase fault and two-phase fault is proposed through revealing the correlation of three phase signals. Thus the reliability of system is increased and the field of application is broadened.Based on above theory analysis, a digital experimental test-bed on DSP and CPLD for DSPM motor driving system is built.更多还原