Design and Control of a Linear Propulsion System for an Elevator Using Linear Switched Reluctance Motor Drives

Linear switched reluctance motors (LSRMs) for the primary propulsion of a ship elevator is proposed and investigated for the first time in this paper. To achieve the stated objective, a new type of LSRM is proposed with twin stators and a translator between them with no back iron in the translator. The proposed configuration of the LSRM is designed, simulated, analyzed, compared with traditional LSRMs, and verified by experimental measurements. The number of LSRM propulsion subsystems required is studied with a view to minimize their weights and an optimization study for that purpose is developed. Unique placement of the LSRM propulsion systems on the elevator is presented. The propulsion force is generated using one phase or multiphase excitation. To reduce propulsion force pulsations, a major requirement in elevators, controlled multiphase excitation using one of the known force distribution functions (FDF) is an acceptable solution. In this paper, it is proved that the currently available FDFs are able to reduce the force pulsations but are not able to meet the peak force command for the system. Consequently, the velocity and position control do not meet even the elementary performance requirements any more. A new FDF is proposed in this paper and presented to overcome the problem caused by a conventional FDF. The control system with the proposed FDF is derived and integrated into velocity and position controllers. Extensive dynamic simulation and experimental verification of the proposed LSRM with the novel FDF is proved to give superior performance in this paper. Such high performance capable of meeting vertical elevator applications is demonstrated.     

一种基于西门子S7-200CPU226CN系列PLC的智能并行控制系统模型

为了实现对工业对象进行智能并行控制,采用可编程控制器（PLC）控制250W,6/4极,3相,24V线性开关磁阻电机（LSRM）。PC和PLC之间使用串行端口进行通信。基于C#语言编制监视和控制程序。软件显示了电机的相位和速度电流,并进行了曲线测量。确定电机的现有位置和脉冲数,并使用线性增量式编码器进行显示。结果表明由PLC控制的LSRM研究引导了工业实践和教育部门强调线性运动的重要性,所有类型的LSRM都可以在开发的系统中使用。     

Novel Switched Reluctance Machine Configuration With Higher Number of Rotor Poles Than Stator Poles: Concept to Implementation

There is a great demand for efficient, quiet, reliable, and cost-effective motor drives for propulsion systems in hybrid and plug-in hybrid electric vehicles. Owing to a rigid structure and the absence of magnetic source on the rotor, a switched reluctance machine (SRM) is inherently robust and cost effective. In spite of these advantages, several challenges in the control of this machine remain an issue, including high levels of torque ripple, acoustic noise, and a relatively low torque density. This paper presents a new family of SRMs which have higher number of rotor poles than stator poles. Using a newly defined pole design formula, several novel combinations of the stator–rotor poles have been proposed. From the simulation and experimental analysis of a prototype 6/10 configuration, it has been observed that this machine produces higher torque per unit volume and comparable torque ripple when compared to a conventional 6/4 SRM with similar number of phases and constraints in volume. The results presented in this paper make this family of machines a strong contender for survivable high-performance applications for automotive propulsion systems. The simulation and experimental results for the prototype 6/10 configuration have been presented and compared to a conventional 6/4 design for verification.      

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     

Electric Motor Drive Selection Issues for HEV Propulsion Systems: A Comparative Study

This paper describes a comparative study allowing the selection of the most appropriate electric-propulsion system for a parallel hybrid electric vehicle (HEV). This paper is based on an exhaustive review of the state of the art and on an effective comparison of the performances of the four main electric-propulsion systems, namely the dc motor, the induction motor (IM), the permanent magnet synchronous motor, and the switched reluctance motor. The main conclusion drawn by the proposed comparative study is that it is the cage IM that better fulfills the major requirements of the HEV electric propulsion     

High-precision position control of a novel planar switched reluctance motor

This paper presents the position control of a novel two-dimensional (2-D) switched reluctance (SR) planar motor. The planar motor consists of a six-coil moving platform and a flat stator base made from laminated mild steel blocks. Unlike conventional x-y tables, which stack two moving slides on top of each other, the proposed 2-D planar motor has the advantages of simple mechanical construction, high reliability, and the ability to withstand harsh operating conditions. Together with the two linear encoders attached to the x-axis and y-axis, the motor can be controlled under closed-loop mode. To combat the problem of force nonlinearity, this paper proposes a cascade controller with force linearization technique to implement the drive controller. Due to the unique structure of the planar motor's magnetic circuit, there is very little coupling between the x-axis and y-axis, and no decoupling compensation is needed. Preliminary results show that the proposed SR planar motor has a positional accuracy of 5 /spl mu/m and a maximum acceleration/deceleration rate of 2 G.     

开关磁阻电机故障诊断系统研究

本文以TMS320F2812为控制器,以四相8/6型开关磁阻电机(SRM)为控制对象,设计了一种性能优良的具有故障诊断功能的开关磁阻电机调速系统。本文介绍了开关磁阻电机调速系统的工作原理,包括功率变换器,电流检测,位置检测,速度检测等硬件电路,并重点分析了系统的故障运行情况。最后给出了实验波形,说明开关磁阻电机具有良好的容错性能。     

Novel encoder for switching angle control of SRM

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with rotor position because the position of the rotor is an essential information. Although high-resolution optical encoders or resolvers are used to provide precise position information, these sensors are expensive. Moreover, in a high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low-cost analog encoder suitable for practical applications is proposed. In addition, the control algorithm to generate switching signals using a simple digital logic is presented. The validity of the proposed analog encoder with a proper logic controller is verified from the experiments.     

Direct control strategies based on sensing inductance in switchedreluctance motors

The stator winding current commutation timing is the central subject of switched reluctance motor control. The direct use of coil inductance information for current commutation is introduced in this paper. The drawbacks of position-based commutation, in the presence of drifting electrical parameters, are overcome by using the instantaneous coil inductance information. Algorithms to optimize torque using this approach are also presented in this paper     

开关磁阻风力发电系统最大风能跟踪控制仿真研究

介绍了开关磁阻发电机工作模式并选用了他励发电模式。在此基础上搭建了以跟踪最大风能为目的开关磁阻风力发电系统模型。针对开关磁阻电机的特点,选择了转速反馈控制方案来实现系统的风能跟踪。在阵风、渐变风、随机风三种典型风速变化下对所搭建系统进行了仿真研究,证明该系统能够完成最大风能跟踪。     

Design and implementation of sensorless techniques for switched reluctance drive systems

This article proposes two different methods for estimating the shaft position for a switched reluctance motor (SRM). Method 1 uses the self-inductance estimation technique to obtain the rotor position. First, by on-line measuring the slope of the stator current and compensating for the back electromotive force (EMF) effect, the self-inductance of the SRM can be detected. Then, the shaft position of the motor can be estimated according to the self-inductance. Method 2, on the other hand, uses the phase-locked loop technique to generate high-frequency signals. These signals can be used to estimate the shaft position of the SRM. The two proposed methods are compared and discussed in the article. Several experimental results are shown to validate the theoretical analysis. The adjustable speed range of the system is from 10 to 3000 rpm. Additionally, the proposed drive system can automatically start from a standstill to a setting speed.     

基于DSP的开关磁阻电机数字化实验平台的设计

针对许多国内大专院校相关课程缺少开关磁阻电机及其控制系统实验器材的现状,设计了全数字开关磁阻电机实验系统,运用数字信号处理器TMS320F2812作为主控CPU设计了电流环、速度环、位置环的闭环控制系统。这一全数字实验平台的设计使得先进的控制算法应用于开关磁阻电机成为可能,可以为相应教学实践环节提供平台。该实验平台具有硬件简单、易于实现等特点,且控制策略修改灵活方便,适合于教学实验使用。     

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。     

Development and Analysis of a High Thrust Force Direct-Drive Linear Actuator

This paper presents the design and analysis of a novel high thrust force linear actuator with high backdrivability. This motor consists of a mover and a stator with spiral (helical) structure. The mover moves spirally in the stator, and the linear motion is extracted to drive the load. This motor is a direct-drive system and highly backdrivable. In this paper, a basic model and thrust-force/torque equations are proposed, and finite-element method analysis and experimental results of a prototype are presented. From experiments, the designed spiral motor achieves 2000-N rated thrust force. The thrust-force capabilities of the spiral motor are compared with other linear motors. It is confirmed that the spiral motor is almost close to the latest state of the art in linear motor technology.     

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     

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.     

Forward converters for dual voltage switched reluctance motordrives

A new circuit is presented which allows a switched reluctance motor to operate from AC mains or a low voltage battery supply. In addition the AC mains can be used to charge the battery. The switched reluctance motor is used as the voltage-changing transformer, potentially reducing the cost of the system. The operation of the drive is explained, and results of an experimental prototype are presented     

Robust speed control of a switched reluctance vector drive usingvariable structure approach

The robust speed control of a switched reluctance vector drive is presented in this paper. An approximate sliding-mode input power controller and another feedforward sliding-mode speed controller are combined with space voltage vector modulation. The resultant drive has rapid and robust speed response. In addition, a switched reluctance motor (SRM) drive incorporating the proposed controller requires only one current sensor and can be implemented in a low-cost 8-bit microcomputer and a few discrete integrated circuits. Furthermore, the controller does not require any offline characterization of the motor or load characteristics and could easily be applied to SRMs with any number of phase windings. A 4 kW four-phase SRM drive is constructed to test the performance of the controller. The results show that a step response from 200 to 1980 RPM needs only 2-3 s, even when driving a high-inertia load, and that the speed error can be controlled below 1%, even under unknown and dynamic loads. It is concluded that modified sliding-made controllers are effective in dealing with the highly-nonlinear characteristics of the SRM drive system     

A Loss-Minimization DTC Scheme for EV Induction Motors

This paper proposes a strategy to minimize the losses of an induction motor propelling an electric vehicle (EV). The proposed control strategy, which is based on a direct flux and torque control scheme, utilizes the stator flux as a control variable, and the flux level is selected in accordance with the torque demand of the EV to achieve the efficiency-optimized drive performance. Moreover, among EV's motor electric propulsion features, the energy efficiency is a basic characteristic that is influenced by vehicle dynamics and system architecture. For this reason, the EV dynamics are taken into account. Simulation tests have been carried out on a 1.1-kW EV induction motor drive to evaluate the consistency and the performance of the proposed control approach     

A novel sliding-mode observer for indirect position sensing ofswitched reluctance motor drives

A switched reluctance motor (SRM) drive generally requires a rotor position sensor for commutation and current control. However, the use of this position sensor increases both cost and size of the motor drive and causes limitations for industrial applications. In this paper, a novel indirect position sensing technique, namely, the sliding-mode observer, is proposed for SRM drives. The corresponding design approach and operating performance are provided to illustrate the fast convergence and high robustness of the observer against disturbances and variations