基于转矩逆模型的SRM转矩脉动抑制研究

开关磁阻电机转矩逆模型的精度对于采用电流控制方式实现转矩控制的系统有很大的影响,文中采用经细菌群体趋药性算法优化后的最小二乘支持向量机建立开关磁阻电机的转矩逆模型,获得电流-转矩-角度特性;进而结合转矩分配函数和电流控制环构SRM转矩控制系统。通过仿真实验表明,该转矩逆模型准确地反映了电机的电流-转矩-角度特性,提高了开关磁阻电机控制系统中电流控制环的精度,并对该系统转矩脉动的抑制有重要作用。     

在线转矩分配函数控制开关磁阻电机策略分析

开关磁阻电机(SRM)因双凸极结构,其内部磁场非线性导致运行过程中会产生较大的噪声和转矩脉动。根据开关磁阻电机数学模型,以四相8/6极SRM作为研究对象,用Matlab/Simulink搭建基于在线TSF策略的转矩脉动控制系统模型。系统将实时转矩跟踪参考转矩,将不确定性因素进行整体逼近减小误差,实现在线TSF控制。仿真结果表明,所提系统建模方法能有效地抑制转矩脉动,并增加其稳定性,为实际电机控制系统的设计提供新的思路及参考依据。     

改进萤火虫算法在雷达伺服电机控制中的应用北大核心CSCD

由于开关磁阻电机(SRM)特殊的双凸极结构,在运行过程中会产生较大的转矩脉动,文中考虑开关角对SRM转矩脉动的影响,在转矩分配函数控制方法的基础之上,采用改进人工萤火虫算法对SRM开关角进行优化,设计一种基于改进萤火虫算法的转矩分配函数控制方法。该方法以铜耗与转矩脉动率作为优化目标,利用改进萤火虫算法的寻优能力,对开关角进行优化。仿真实验表明:该方法在工况1000 r/min下,相较于传统转矩分配函数控制策略,转矩脉动率减小了5.3%,在2000 r/min下,减小了5.23%。     

基于转矩分配函数的开关磁阻电机的控制

转矩脉动较大是开关磁阻电机(SRM)的主要缺点,为了减小转矩脉动,提高电机性能,将转矩分配策略应用到电机中,能有效抑制转矩脉动。但由于开关磁阻电机的非线性,使得设计转矩分配函数变得很困难,传统的线性函数虽然简单,但无法体现开关磁阻电机的非线性。虽然非线性正弦函数的提出使得转矩性能得到了提高,但在换相区的效果还是不尽理想。为了解决这个问题,文中提出一种滞环补偿性转矩分配函数,仿真证明了该方法的有效性。     

一种开关磁阻电机模糊PI的直接瞬时转矩控制

噪音是开关磁阻电机应用中的一大难题。针对开关磁阻电机运行过程中转矩脉动较大的问题,采用有限元计算方法所得到的电机模型,在MATLAB中进行开关磁阻电机模糊PI直接瞬时转矩控制的仿真实验。采用Ansoft电磁场仿真软件,搭建了三相4/6开关磁阻电机,并将得到的磁链数据导入MATLAB电机模型中。随后,利用该模型搭建模糊PI直接瞬时转矩控制的Simulink仿真实验平台。实验结果发现,系统在0.01 s时开始响应,转矩浮动在0.05~0.1 Nom之间。该结果表明,将有限元得到的电机模型应用到模糊PI直接瞬时转矩控制的仿真实验中时,可以提高系统响应,并有效抑制转矩脉动。     

开关磁阻电机基于转矩脉动最小化的直接转矩控制技术

开关磁阻电机的主要缺点是转矩脉动较大以及振动和噪声比其他调速系统严重。这里将直接转矩控制技术应用到开关磁阻电机中,以转矩脉动最小化为主要控制目标,在此基础上建立了直接转矩控制的仿真模型。仿真及实验研究表明,直接转矩控制技术能够将磁链矢量幅值很好地控制在滞环带内,从而有效地控制转矩脉动,降低电机的振动和噪声。     

开关磁阻电机优化设计方法的研究

开关磁阻电机的主要缺点是运行时转矩脉动、噪声和振动比较大,要改善它的性能一般从电机本体结构优化和电机控制优化两个方面进行。本文主要从电机结构尺寸和参数优化设计方面,阐述使开关磁阻电机转矩脉动、噪声和振动降低的方法以及发展趋势。     

基于BP神经网络的开关磁阻电机直接转矩控制建模与仿真

开关磁阻电机具有特殊的双凸极结构,导致其运行时会产生严重的转矩脉动,直接转矩控制可显著降低转矩脉动。但由于磁路的严重饱和,传统方法利用公式计算转矩过程非常复杂,提出一种基于BP神经网络来预测开关磁阻电机转矩,进而进行直接转矩控制的策略。通过有限元仿真得到训练数据经离线训练之后,即可得到输入量到转矩的非线性映射,该控制方法利用BP神经网络泛化、逼近能力强的优点,省去了复杂的转矩计算,同时可以对转矩脉动进行抑制。仿真和实验结果表明,该方法响应速度快,控制精度高。     

浅析磁阻电机内部的机电能量转换原理

针对旋转式磁阻电机的工作原理，分析其内部的机电能量转换关系，推导出电磁转矩与磁共能的关系和实现机电能量转换的条件，为一种定、转子极数相等的开关磁阻电机的设计提供基础。     

基于改进的支持向量机的开关磁阻电机的模型建立

开关磁阻电机具有结构简单、工作可靠、运行效率高等优点。但开关磁阻电机的磁路高度饱和、非线性化,很难建立准确的数学模型,难以实现高精度控制。在研究开关磁阻电机的电磁与转矩特性的基础上,结合支持向量机算法在解决小样本、非线性、高维数、局部极小值问题上的优势,建立了径向基函数核函数的支持向量机的开关磁阻电机的数学模型,通过仿真与传统BP神经网络算法对比,证明该算法具有较高的性能,实验平台检测的数据表明,所构建的开关磁阻电机模型是可行的,证明了模型的正确性和有效性。     

Sensorless torque control of SyncRel motor drives

This paper describes a direct self-control (DSC) scheme for synchronous reluctance motor drives. The presented DSC scheme develops a new torque control methodology that does not require any position transducer to synchronize the stator current vector with the rotor. Such a control strategy differs from the conventional DSC approach in order to fit some specific requirements of synchronous reluctance (SyncRel) machines. First, torque and rotor position are controlled instead of torque and stator flux as in a conventional DSC scheme. Second, the operating sector is selected according to the actual position of the current vector rather than the position of the stator flux. The proposed methodology allows simplifying implementation of the torque control on SyncRel drives and reducing the global cost for medium-performance electric drives. Simulations and experimental tests on a 1.5-kW motor drive are provided to evaluate the consistency and the performance of the proposed control technique     

Control of switched reluctance drives for electric vehicleapplications

Dynamic controllers of switched reluctance drives adjust at least three variables, i.e., current amplitude, turn-on, and turn-off angles. In electric vehicle (EV) applications high efficiency of the drive over a wide speed range, wide torque bandwidth, and low torque ripple under varying DC-bus voltage conditions are important design goals. Hence, controllers of switched reluctance drives for EVs usually have a complex structure. In this paper, the demands on control accuracy of switched reluctance machine traction drives and the traction controller sampling frequency, which are necessary to take advantage of the switched reluctance machine dynamic capabilities, are discussed. To integrate the traction drive, the control commands need to be actualized with a sampling frequency of at least 100 Hz to meet the high-dynamic requirements of modern vehicle control systems, e.g., active cruise control, antislip control, and active damping of mechanical drivetrain oscillations. It is found that the switching angles have to be adjusted within one-tenth of a mechanical degree. This study shows that switched reluctance drives can fulfill all requirements needed for electric propulsion using standard microcontrollers or digital signal processors     

Motor control and torque coordination of an electric vehicle actuated by two in-wheel motors

In this research, an electric vehicle actuated by two in-wheel DC motors is developed. By properly coordinating the motor torques, both drive-by-wire and electrical steering can be achieved. Two critical issues respectively related to the design of motor controllers and the coordination of the two motor torques under control saturation are investigated in this study. Firstly, as for the in-wheel motors that are used for driving and steering simultaneously, their operation covers a wider dynamic range that forward acceleration (deceleration), and reverse acceleration (deceleration) may occur alternately. To perform driving and steering smoothly and efficiently, each motor should be switched to an appropriate mode to generate the torque demanded. Secondly, during the high-speed maneuvering, the high back-emf voltage in the motor coil substantially reduces the motor’s torque generating capability. Since the electrical steering depends on the differential torque of two wheels, when electrical steering is demanded in this case, torque/current saturation may occur in either one of the motors and the electrical steering performance could be seriously degraded. To address these issues, controllers of two levels are proposed. For the low-level controller (the motor controller), it operates the motor automatically in an appropriate mode for performance and efficiency consideration. An input transformation is introduced to cancel the nonlinearity in current dynamics so as to control the motor torque easily and precisely regardless of mode switching. For the high-level controller (the torque coordination controller), besides generating reference commands to the low-level controllers, during control saturation it can also properly re-distributes control signals to maintain consistent steering performance and provides compensation for integrator windup. The control system is implemented and the performance is experimentally and numerically validated.     

电动助力转向系统无刷电机温度研究

电动助力转向系统由控制器ECU根据传感器手力矩、车速等信息确定电机助力,电机与ECU热管理是其成本控制与系统安全的关键。文中提出在控制中区分快速与慢速发热模型,得到了系统温度的增加值,在不同发热均恒条件下与当前温度、输入电流的关系,估算电机温度。仿真与实验证明,通过这种热管理分析与设计方法有效地解决了系统发热问题,成功地实现了系统成本与系统安全的统一。     

Iterative learning control of antilock braking of electric and hybrid vehicles

Hybrid electric vehicles (HEVs) use multiple sources of power for propulsion which provides great ease and flexibility to achieve advanced controllability and additional driving performance. In this paper, the electric motor in HEV and electric vehicle (EV) propulsion systems is used to achieve antilock braking performance without a conventional antilock braking system (ABS). The paper illustrates that the antilock braking of HEV can be easily achieved using iterative learning control for various road conditions. A vehicle model, a slip ratio model, and a vehicle speed observer were developed to control the antilock performance of HEV during braking. Through iterative learning process, the motor torque is optimized to keep the tire slip ratio corresponding to the peak traction coefficient during braking. Simulations were performed on a compact size vehicle to validate the proposed control method. The control algorithm proposed in this paper may also be used for the ABS control of conventional vehicles.     

A torque controller suitable for electric vehicles

A torque controller suitable for electric vehicles is studied. The controller ensures that an induction motor generates motor torque efficiently, stably and accurately. The torque control system feeds back an assumed motor torque calculated using the secondary magnetic flux and the torque current detected from current sensors of the primary currents. The motor torque is controlled by using the torque current reference determined from the generated secondary magnetic flux and the magnetizing current reference. The magnetizing current reference is determined on the basis of the torque current reference so that motor torque generation efficiency is always optimal. The magnetizing current regulator is operated according to the magnetizing current reference. This ensures the motor generates the motor torque stably even in transient states. Fundamental performance characteristics, such as response, accuracy and efficiency of the motor torque are verified by simulation and experiments. The torque controller is judged suitable for the drive system of electric vehicles     

电动汽车用充电器与驱动器一体化拓扑研究

摘要：针对电动汽车驱动与充电系统分离所带来的诸多问题,提出了一种电动汽车驱动和充电系统一体化电力电子拓扑结构及相应控制策略, 该拓扑正向工作时驱动电机为电动状态、反向工作时给蓄电池充电为充电状态。一体化拓扑在充电时共用驱动系统的主电路和控制电路,无需额外增加AC/DC和DC/DC充电器,提高了功率密度、降低了产品成本、降低了系统故障率、减少了安装空间等,解决了传统电动汽车驱动与充电分离带来的问题。最后针对提出的一体化拓扑和控制策略进行了实验验证,试验中所采用电机型号为80CB050C,结果表明该一体化拓扑在充电实验时直流母线电压纹波在6.9%附近,经过Buck电路中电机绕组进一步滤波后,充电电压及电流纹波基本稳定在0.3%以内,验证了所提方法的正确性和可行性,具有一定的应用前景和实用价值。     

Control of switched reluctance motor torque for force controlapplications

The paper presents a method for controlling switched reluctance motor (SRM) torque for force control applications. SRMs are used in AdeptOne robots, and the authors perform experiments with two robots, controlled in coordination, in grasping and manipulation of various objects. The object and robot parameters are not exactly known, and adaptive methods are used to control the overall system. These methods are model-based control techniques which require high bandwidth torque control. This requirement is typical for high precision mechanisms. SRM characteristics are very nonlinear. In particular the torque ripple, friction, and the torque versus position and current relationships were analyzed in the context mentioned above, and specifically, for force control applications. The proposed method is based on a new commutation algorithm and a measured torque versus position and current relationship, used to smooth the SRM's torque ripple, hence generating a torque output nearly independent of position. Furthermore, the internal friction is estimated on-line, and compensated for. This renders a high accuracy torque tracking. The torque control method is based on feedback from the motor angular velocity, motor angle, armature current, and feedforward for friction compensation and cancellation of nonlinear effects. The method has been tested experimentally on Adept motors and the results were very encouraging. The method has been also used for adaptive control of two coordinated Adept robots