【作者】 罗建武；

【导师】 詹琼华；

【作者基本信息】 华中科技大学 ， 电机与电器， 2007， 博士

【摘要】 与单电机驱动电动汽车相比,轮毂电机驱动系统驱动的电动汽车在动力源配置、底盘结构和车辆操控性等方面有其独特的技术特征和优势,是电动汽车发展的一个独特方向。电机驱动系统是电动汽车的三大关键零部件之一,可供选用的电机型式多种多样,性能各有千秋。其中开关磁阻电机(SR电机)以其简单牢固的结构、优异的性能而成为优选方案之一,经过近20年的不断努力,在汽车应用领域已取得了一大批研究成果并投入实际应用,发挥了巨大的社会效益和经济效益。在此基础上开展开关磁阻电机轮毂驱动系统的研究已成为必然。全文共分为七部分:简要介绍了电动汽车的发展概况和关键技术,对关键技术之一的各种电机驱动系统进行了分析比较,详细介绍了SR电机驱动系统的最新发展水平和研究方向及其应用于电动汽车的优缺点。对轮毂电机电动汽车的优点进行了阐述,总结了国内外轮毂电机电动汽车的发展近况。通过对现代汽车控制理论和技术的简要综述,明确指出对汽车的控制实质上是控制轮胎与路面间的作用力(包含驱动力和制动力),合理控制作用力能够实现先进的车辆控制技术,如驱动力控制(TCS)和稳定性控制(VSC),使得驾驶员对车辆的控制更为灵活稳定,提高了车辆在各种路面条件下的行驶性能。轮毂电机型式的电动汽车上各驱动轮具有各自独立的电机驱动系统,轮毂电机驱动系统的研究目标应是实现驱动轮驱动力矩、制动力矩的闭环控制。在分析常用的SR电机转矩闭环控制策略的基础上,针对其中的不足之处,提出了基于磁链检测的转矩控制策略。采用多变量(相电流、开通角和熄弧角)控制技术,彻底消除了传统控制中由于控制模式切换引起的转矩不平顺性。采用变结构PID控制相电流实现转矩闭环控制;从减小相电流峰值、有效值,提高电机效率和功率器件利用率的角度对开通角进行了优化;从控制定转子对齐位置相电流值减轻电机振动噪声的角度对熄弧角进行了优化,并详尽阐述了基于磁链平衡实现熄弧角控制的方法,最后进行了MATLAB/Simulink仿真研究。对磁链检测的精度进行了深入研究。运用有限元分析软件ANSYS7.0,对SR电机内部磁场分布进行了仿真分析,分别计算出电机绕组和检测绕组磁链及其相对误差,分析了检测绕组的匝数以及布置方式对相对误差的影响,得出了具有普遍意义的布置原则。研究了相间互感的影响,分别对NSNSNS、NNNSSS两者连接方式的磁场分布和电感矩阵进行了分析计算并结合实验,得出采用NSNSNS连接方式,相间的影响相互一致,一相的磁链、电流数据可精确地代表其余两相,电机转矩估算将具有更高的精度和准确性。详细阐述了硬件积分器的各种误差源,并针对每一种误差源给出了误差的解析表达式,通过分析可知采用低噪声高精度运算放大器OP-27构建的积分器在SR电机的各种工况下均具有非常高的精度。采用对比分析的方法对SRG的基本工作原理和特性、转矩闭环控制策略中转矩估算、电流滞环控制以及开关角度控制进行了研究。提出了基于磁链平衡的θextG控制方法。对SRG中可能出现的绕组电流失控问题进行了较为深入的分析,总结出了失控电流的变化规律,提出了具有针对性的控制措施。最后对转矩闭环控制策略进行了仿真计算,结果表明所采用的控制策略具有良好的动静态特性。构建了SR电机实验平台并进行了详尽的实验研究。设计并制作SR电机控制器,控制部分采用TI公司的DSP TMS320LF2407A并配合相应的外围元件,功率变换器采用非对称半桥电路,功率器件采用FUJI公司的IGBT 2MBI100-060L。为便于制动实验,研制了高频斩波负载装置,实现了发电电压的稳定和任意调节。设计了硬件积分器的校正电路。实验项目主要包括:电动(和制动)转矩-转速静态特性、电动(和制动)转矩阶跃响应动态特性、电动-制动间转换转矩阶跃响应特性。实验结果表明,采用本文提出的转矩控制策略,SR电机具有良好的转矩动静态特性。为了实现SR电机绕组电流或磁链的精确控制,必须提高SR电机功率变换器的工作频率以提高系统的动态响应速度。然而,较高的工作频率会引起严重的电磁干扰(EMI)和开关损耗从而导致系统整体效率降低。结合谐振开关(RS)、直流谐振环(RDCL)和脉冲宽度调制(PWM)的优点,提出了一种新型的软开关SR电机功率变换器,通过在非对称桥式电路的基础上增加一套换流电路,以此实现功率器件的软开关。在对变换器工作原理详细分析的基础上,导出了实现软开关的条件并给出了设计实例。仿真和实验研究证实了新型软开关SR电机变换器的可行性。更多还原

【Abstract】 Compared with signal motor drive electric vehicle (EV), in-wheel motor drive EV will be a tendency of development because of its unique characters of chassis structure and vehicle manipulation. Motor drive system is one of three key parts of EV. There are diverse types of motor drive system with difference performance, Switched Reluctance Motor (SRM) is preferred because of its simple robust structure and outstanding performance. After 20 years study and development, SRM is succeed in application in EV domain, and is beneficial to economy and environment. This dissertation is devoted to the fundamental and experimental research of in-wheel SRM drive system, and is composed of following seven aspects.First of all, the development history and the critical techniques of electric vehicle are discussed, and the characters of diverse motor drive system are compared. As a promising candidate, the newest evolution of SRM and its merits and demerits for EV usage are particularly presented. The advantage and up to date development of in-wheel motor drive EV are summarized. Combining the advantages of in-wheel motor drive system and SRM, the research on SRM in-wheel motor drive system is becoming necessary.By analyzing vehicle theory and technique, the essence of vehicle manipulation is indicated, i.e. controlling force between road surface and tires (include traction force and brake force). By properly controlling the force, some advanced vehicle manipulation strategies, such as traction control system (TCS) and vehicle stability control (VSC), can be fulfilled. For in-wheel motor drive EV, every propelling wheel has its own motor drive system, the principal character in-wheel motor drive system should have is average torque closed-loop control.To overcome the shortcoming of conventional torque control of SRM and fulfill closed-loop average torque control for SRM more precisely, a novel torque control strategy is presented. By placing auxiliary gauge winding on the stator pole and adopting hardware integrator, the flux linkage is measured. Utilizing flux linkage and phase current, the output electromagnetism torque can be calculated. Synthesizing traditional CCC and APC mode, a multiparameter (phase current hysteretic threshold i ref, turn-on angleθon and extinguish angleθext) adjustment algorithm is adopted. i ref is used to decrease torque error by PID controller, meanwhileθon is used to minimize the peak and root-mean-square value of phase current, andθext is used to reduce vibration and acoustic noise of motor. A method based on flux linkage balance to control extinguish angleθext is presented in detail. Simulation software MATLAB/Simulink is used to validate the torque control strategy.To evaluate flux linkage measurement, flux linkage of phase winding and gauge winding with different turns and layout are calculated respectively using FEM software ANSYS 7.0, from calculation results of relative error the optimizing layout of gauge winding is find out. There are two connecting mode for three-phase SRM, i.e. NNNSSS and NSNSNS. By analyzing magnetic field distribution, calculating inductance matrix and experimental test, NSNSNS is proved to be a good connecting mode, which has virtue of working consistently and high torque estimation accuracy. The error analysis of hardware integrator is executed, low noise high precision operational amplifier OP-27 is precise enough for SRM application.SRM’s generator operation mode is very important for EV application. Compared with SRM, this dissertation contrastively discusses the fundamental theory and characters, torque estimation, current hysteresis control and angle control of Switched Reluctance Generator (SRG). A method based on flux linkage balance to control extinguish angleθextG is presented in detail. For the special uncontrollable phase current, this dissertation presents the mechanism and the solution. Using simulation software MATLAB/Simulink validates the braking torque closed loop control strategy.A SRM torque control experimental facility is established, and a series of experimental research are conducted to validate the proposed torque control strategies. Hardware implementation of a SRM controller is achieved using Texas Instrument’s TMS320LF2407A Digital Signal Processor (DSP) and some peripheral devices. The converter topology is asymmetric half-bridge circuit, power device is FUJI’s IGBT 2MBI100-060L. To achieve generator (braking) test, a special high-frequency loading device is designed, which has the ability of regulating voltage. Correcting circuit is made for hardware integrator. Experimental items include torque-rotational speed character, acceleration/deceleration character, torque stability character, torque step response character and motor/generator conversion character. From experimental results, the torque control strategy presented in this dissertation is thus proved to be effective, which has advantages of high precision and fast dynamic response.To improve the performance of switched reluctance motor (SRM) drives, some advanced control strategies have been proposed, such as current or flux linkage profile control. To achieve these strategies the motor phase current or phase flux linkage should be controlled precisely. All these require increasing the switching frequency of converter to increase dynamic response speed. However, higher switching frequency may cause higher switching losses, and thus higher Electro-Magnetic Interference (EMI) and lower overall efficiency. The use of soft-switching techniques in converter can resolve these issues. In this chapter a brand new soft-switching converter for SRM is presented, which has advantages of all Resonant Switch converter (RS), Resonant dc Link converter (RDCL) and Pulse Width Modulation (PWM). The addition of external commutating devices to conventional asymmetric bridge converter for SRM achieves the soft-switching of power devices. The conditions of soft switching are deduced and a practical design consideration is given. Finally, detailed simulation study of the complete system is presented and validated with experimental results.更多还原