【作者】 彭思仑；

【导师】 宋传学；

【作者基本信息】 吉林大学 ， 车辆工程， 2014， 博士

【摘要】 随着能源与环境问题日益突出，电动汽车开始成为未来汽车工业发展的主要方向，其驱动电机如同内燃机汽车的发动机一样是非常关键的动力执行部件，主要分为集中式电机驱动和轮毂电机驱动。与传统的集中电机驱动相比，使用轮毂电机轮驱动系统可以简化驱动系统和整车结构，减小机械效率损失，同时各轮毂电机的驱动力可独立控制，动力学控制非常灵活、方便。但轮毂电机受限于轮毂内有限的体积，驱动扭矩较小，目前还难以满足汽车对动力性的需求，因此本文对电机控制策略进行了研究，分析了影响转矩输出的影响因素，从而得出优化电机转矩输出的方法，使电机在现有技术条件下尽可能的输出其应有的转矩。目前电机控制理论的发展主要集中在降低电机参数时变特性对电机控制系统稳定性的影响，较少关注其导致的电机输出转矩下降问题。电机参数变化对磁场定向准确性的影响导致了电机无法完全获得其全部输出转矩，同时电机逆变器中PWM信号频率也会对转矩输出有所影响。因此本文从优化转矩输出的角度，对PWM变频频率策略和电机进角控制策略进行了深入研究：本文首先介绍了轮毂电机技术目前的研究状况和应用现状，对比分析了几种适用于轮毂电机的电机类型。由于永磁同步电机较高的功率密度，可在低速下获得较高的输出转矩等特性，在轮毂电机应用中具有明显优势，因此选择永磁同步电机作为本文研究对象。然后对电机控制理论的发展状况进行了阐述，在总结各种研究成果的基础上，提出了对轮毂电机应用的转矩优化思路。对永磁同步电机的空间矢量控制和直接转矩控制这两种基本的控制算法进行了对比分析，由于空间矢量的控制方法扭矩波动小，低速时可获得全负荷输出，更适合轮毂电机使用，因此本文基于矢量控制研究电机输出扭矩的优化算法。首先从PWM变频控制的角度研究了扭矩优化策略，通过对PWM开关频率对电机性能影响的分析，得出了较低的PWM频率可减小电机逆变器的损耗，同时利用了谐波扭矩，可在低速下获得更高的输出转矩，并由此设计了相应的变频控制策略以提高低速下电机性能。其次从进角控制的角度进行了扭矩优化策略的研究，对影响磁场定向准确度因素进行分析，主要包括三个方面：(1)位置传感器的测量精度影响(2)电机参数时变特性的影响(3)换向延迟角的影响。针对这种复杂的、非线性的外界干扰，提出了基于直轴电流反馈的控制策略和神经网络前馈的控制策略，通过对比可知，神经网络的控制策略要更适合进行进角控制，以直轴电流最小为控制目标进行设计，可以提升高速时电机输出转矩。通过Simulink商业化的工具箱Simscape建立了电机仿真模型，并根据实际的电机控制芯片工作原理，建立了PWM信号发生器和死区模块，以精确模拟实际的电机控制过程。对本文提出的转矩优化策（PWM变频控制策略和进角控制策略）进行了设计并建立了相应的控制模型。对这两种控制策略分别进行了仿真验证，仿真结果表明PWM变频控制利用谐波扭矩增加了低速下电机输出扭矩，进角控制则通过神经网络控制算法减小了换相延迟角从而增加了高速下电机输出扭矩。最后综合运用这两种控制模块进行了仿真，仿真结果表明该控制策略提高了整体的电机输出扭矩，电机的性能得到提高。为了快速进行实物验证，搭建了基于Simulink的电机控制器快速原型开发平台。通过对Matlab的快速原型技术机制进行研究，得出了广泛适用于各种微控制器芯片的快速原型设计方法，该方法通过对系统目标文件的编写，使Matalb的自动代码生成功能可支持多种微控制器芯片型号，不再受其芯片型号的限制。该方法是对Matlab原有快速原型技术的一种扩充，使Matlab快速原型技术不再局限在常用的芯片平台，对于任何一种控制器芯片，均可采用该方法使Matlab快速原型技术支持该芯片，从而使科研人员能够集中更多精力在控制算法的研究上，而不是嵌入式代码的编写。应用该方法对轮毂电机控制器的快速原型进行了设计，硬件基于TI公司C2000系列DSP的电机控制器解决方案，搭建了针对该解决访案的快速原型平台，采用AD2S1210对位置传感器进行解码，AD7606检测电流传感器的信息。对已经通过仿真验证的矢量控制算法模型生成了对应的嵌入式C代码，实现了轮毂电机控制器的快速原型。基于所设计的电机控制器，搭建了电机试验台架，对电机的参数进行了试验，并根据本文提出的方法得出了相应的转矩优化策略。对所设计的优化策略进行了相关试验和对比分析，通过实验数据可以看出，所设计的转矩优化策略提高了电机矢量控制时磁场定向的准确性，从而提高了电机性能。本文对影响电机输出转矩的因素进行了分析，并针对这些影响因素设计了相应的转矩优化策略，通过仿真和台架的试验验证，证实了该优化策略可提高电机输出转矩，为轮毂电机在电动汽车上的应用奠定了基础。更多还原

【Abstract】 With the energy and environment issues becoming more prominent, the electric vehiclebecomes the main development direction of automobile industry in the future. Its drivingmotor, which is divided into centralized driving motor and in-wheel motor, is the key poweroutput part, just as the engine in the traditional vehicle. Comparison with traditionalcentralized driving motor, the transmission system can be simplified and the mechanicalefficiency losses are deduced with the in-wheel motor. Meanwhile, each wheel can be drivenindependently and thus the dynamic control is easy to achieve. But the output torque islimited by the space in the wheel and is hard to meet the torque demands of vehicle. So inthis paper, the motor control strategy is researched in the aspect of torque optimization. Theinfluences on output torque are analyzed and the strategy of torque optimization is obtained.With the optimization, the proper torque of motor is generated as more as possible on thecurrent technology condition.For now, the motor control theories are focusing on the influence reducing on thecontrol system stability by the varying characteristics of motor parameters. But the motortorque decline problem caused by the varying motor parameters is less concerned. The motorcan’t generate the whole torque because of the inaccuracies field orientation which could becaused by varying motor parameters. In addition, the motor output torque is also affected bythe Pulse Width Modulation (PWM) signal frequency in the motor inverter. So from theperspective of optimizing the torque output, the variable PWM frequency control strategyand motor timing control strategy is researched in the paper.At first, the present research and application situation of in-wheel motor are introduced,and the types of in-wheel motor are analyzed comparatively. Finally the Permanent MagnetSynchronous Motor (PMSM) is chosen in the paper. Because the PMSM has higher powerdensity and higher torque at low speed which are the obvious advantages in the in-wheelmotor application. Then the motor theory development situation is elaborated, and based on the summarization of various research results, the torque optimization methods for in-wheelmotor are proposed.The two basic control algorithms of PMSM, the space vector modulation control andthe direct torque control, are analyzed comparatively. As the space vector modulation controlhas small torque ripple and could get full load output, which is more suitable for thein-wheel motors. The motor torque optimization algorithm is researched based on spacevector modulation control in the paper. Firstly, the torque optimization strategy is studiedthrough variable PWM frequency control. Based on analyzing the influence of PWMfrequency on motor performance, the conclusion that lower PWM frequency decreases thelosses on the motor inverter and getting higher output torque at low speed by utilizingharmonic torque is obtained. Then the corresponding variable frequency control strategy isdesigned to improve motor performance at low speed. Secondly, the torque optimizationstrategy is studied through timing control. The influences on field orientation accuracy areanalyzed, which include the influence of position sensor accuracy, varying motor parametersand commutation delay angle. For the complex and nonlinear disturbance, the controlstrategies based on direct-axis current feedback and neural network feedforward areproposed. By comparing the strategies, the neural network control is more suitable for timingcontrol, and the motor torque output is improved at high speed with the design purpose ofzero direct-axis current.A motor simulation model is built with Simscape, a commercial toolbox in Simulink.And a PWM signal generator with dead band module is built based on actual operatingprinciple of Motor control chip to simulate actual motor control process accurately. Thetorque optimization strategy, PWM frequency conversion control strategy and angle timingcontrol strategy, is proposed in this paper. The two strategies are verified in the simulationand the result shows that the low speed output torque of motor is increased with PWMfrequency conversion control by utilizing harmonic torque, and the high speed output torqueof motor is increased with timing control by decreasing commutation delay angle throughneural network Control algorithm. Finally, the torque optimization control combined with the two control strategy is simulated, and the result shows that the optimization strategyincreases the motor output torque in the whole speed range and the performance of the motoris improved.In order to verify physical model quickly, a rapid prototyping development platform formotor controller based on Simulink is built. Through the study of the mechanism of rapidprototyping technology in Matlab, a rapid prototyping method is obtained that can be usedwidely in all kinds of micro controller chip. This method, based on writing the system targetfile, can make various micro controller chip supported by the automatic code-generationfunction of Matlab, no longer will it be restricted by the type of chip. The method is anextension to the original Matlab rapid prototyping technology, to make the Matlab rapidprototyping technology no longer confined to the common chip platform. For any kind ofcontroller chip, this method can be used to make the chip supported by the Matlab rapidprototyping technology, which enables researchers to focus more energy on the research ofcontrol algorithm, instead of writing embedded codes. Based on the motor controllersolutions of Texas Instruments (TI) Company’s C2000series, the rapid prototyping design ofin-wheel motor controller is accomplished with the method, and rapid prototyping platformis set up aiming at the solution. The AD2S1210chip is used to decode the position sensorand the AD7606chip is used to measure current sensor output. Using the model of vectorcontrol algorithm which has been validated by computer simulation, the correspondingembedded C code is generated, and the rapid prototyping of in-wheel motor controller isachieved.Based on the motor controller designed, a motor test bench is built. The characteristic ofmotor is tested in this bench and the corresponding torque optimization strategy is proposedin this paper. Tests are also carried out to validate the optimization strategy. The Resultshows that the designed torque optimization strategy promotes the accuracy of fieldorientation of vector control and so the performance of motor.The factors that can affect the output torque of motor are analyzed, and thecorresponding torque optimization strategy is designed aiming at the factors. The Results of simulation and test show that the optimization strategies can promote the output torque andlay foundations for the applying of in-wheel motor in electric vehicles.更多还原