Fault-tolerant switched reluctance motor drive using adaptive fuzzy logic controller

An adaptive fuzzy controller has been designed to develop a high-performance fault-tolerant switched reluctance motor (SRM) drive. The fuzzy controller continuously adapts its properties to regulate the machine torque as desired by the drive system even under fault conditions. The adaptation of the fuzzy membership functions results in extended conduction period and increased peak current of the healthy phases to deliver the commanded torque, as much as possible. The adaptive fuzzy controller provides smooth torque output with minimum ripple, even under fault conditions, yielding a high-performance SRM drive with fault-tolerant capability.     

Dual-decay converter for switched reluctance motor drives inlow-voltage applications

A modified converter topology for star-connected switched reluctance motors suitable for low-voltage applications is proposed. A dual-time-constant freewheeling circuit has been designed to improve the drive performance and efficiency over a wide range of speeds. The different modes of operation of the converter are discussed, and a comparison is made with other converter configurations     

Use of fuzzy logic for modeling, estimation, and prediction inswitched reluctance motor drives

Switched reluctance motor drives may be used in many commercial applications due to their simplicity and low cost. These drives require rotor position feedback to operate. However, in many systems, rotor position sensors have disadvantages. In this paper, a position sensorless scheme is described which uses fuzzy modeling, estimation and prediction. An important feature is that saturation and real-time nonideal effects are not ignored, but that no mathematical model is required. Instead, a fuzzy logic-based model is constructed from both static and real-time motor data, and from this model the rotor position is estimated. The system also incorporates fuzzy logic-based methods to provide a high robustness against noise. This includes a fuzzy predictive filter which combines both fuzzy logic-based time-series prediction, as well as a heuristic knowledge-based algorithm to detect and discard feedback signal error. In addition, the method uses heuristic knowledge to choose the most desirable phase for angle estimation in order to minimize the effect of feedback error. It is also shown that, by using fuzzy logic, the estimation scheme offers a high robustness and reliability and is thus well suited to a wide range of systems     

A current modulation scheme for direct torque control of switched reluctance motor using fuzzy logic

The paper addresses a fundamental control issue in switched reluctance motor (SRM) drives — the torque ripples. Normally, torque ripple minimization is achieved by using a look-up tables, i.e., the look-up tables uses stored magnetic characteristics to provide the reference current, on-angle, and off-angle for a given torque. A number of techniques for the generation of reference current profiles that minimize the torque ripples have also been suggested in the past. But due to highly nonlinear characteristics of the SRM, all these schemes are not fully successful. Moreover, their performance depends greatly on the accuracy of the magnetic characteristics measurements of the motor on which most of these algorithms work. Our work is primarily motivated to modulate the reference phase current pattern with the aid of fuzzy logic which is well suited to compensate for the nonlinearities of the system, so that the torque ripples are further suppressed. Performance of the proposed strategy is verified by computer simulation.     

Indirect angle estimation in switched reluctance motor drive usingfuzzy logic based motor model

In this paper, a novel rotor position estimation scheme is described that was developed to overcome the drawbacks of the previous sensorless techniques, which were proposed for switched reluctance (SR) motor drives. It is based on fuzzy-logic, and does not require complex mathematical models or large look up tables. The scheme was implemented by using a digital signal processor. The real-time experimental results given in this paper show that the position estimation method proposed can provide accurate and continual position data over a wide range of speeds (zero/low/high), and can also function accurately at different operating conditions (chopping/single pulse mode and steady state/transient operation)     

Power-factor correction for switched reluctance drives

This paper evaluates the need for power-factor correction (PFC) in switched reluctance drive systems supplied from single-phase mains. The aim is to achieve interference values lower than the prescribed norms at minimal system costs and volume. It is shown that for certain applications, a PFC circuit has to be implemented, but simpler technical solutions are often possible. Finally, a suggestion is presented as to how a low-cost power-factor-corrected system should be built for high-volume production     

Modeling, Simulation, and control of switched reluctance motor drives

This paper presents the modeling, simulation, and control aspects of four-quadrant switched reluctance motor (SRM) drives. The design of SRM drive systems must be focused on application-based appropriate control and engineering solutions needed to overcome the practical issues. A complex model is described for the physical motor simulation to incorporate the important dynamics of the SRM. A simpler, but quite accurate, model is presented for the SRM controller. Various practical limitations have been incorporated in the simulation model to make it closer to the experimental setup. The SRM control parameters are chosen based on torque-per-ampere maximization requirement. Experimental results for a 1.0-kW SRM obtained on a digital platform are presented along with useful guidelines for prototype implementation.     

单绕组磁悬浮开关磁阻电机无位置传感器研究

由于位置传感器成本高,受温度和噪声的干扰,增加电机结构的复杂度等缺点,文中研究了一种高性能实用的无位置传感器方法,利用单绕组磁悬浮开关磁阻电机相绕组之间的互感和位移的关系,将一高频测试电流注入A相的任一极,引起在相邻两极的端电压互感增量,滤除互感电压并经过滤波器解调得到包含转子位移的直流部分,然后经过数学处理得到转子位移,实现径向位移自检测,最后通过实验验证该方法的正确性和有效性。     

Performance analysis of photovoltaic pumping systems using switched reluctance motor drives

A photovoltaic (PV) pumping system using a switched reluctance motor (SRM) is investigated in this work. the motor is supplied by a DC voltage through a simple switching circuit. This drive circuit is much simpler than the normal DC/AC inverter required to supply an induction motor. the efficiency of the SRM is considerably higher than that of equivalent DC or induction motors. In addition, because of its simple construction, the SRM is cheaper than these conventional drives. These advantages give the proposed system higher efficiency and lower cost compared with other systems. In this paper, which has a substantial tutorial content, a design example is studied in detail to explore the advantages of PV pumping systems based on the new drive. Study of the performance of the proposed system showed that the operating efficiency of the motor is about 85% during most of its working time. the matching efficiency between the PV array and the proposed system approaches 95%. the major part of the losses takes place in the pump and the riser pipes; this loss represents one-third of the total available energy.     

Nonlinear internal-model control for switched reluctance drives

A nonlinear internal-model control (IMC) based on suitable commutation strategy for switched reluctance motors (SRMs) is proposed. In the commutation strategy, a fixed critical rotor position is defined as the commutation point, which results in reduced computation. Combined the simplicity of the feedback linearization control and the robustness of IMC structure, the proposed drive has excellent dynamic and static performances for the torque and current control. The scheme is analyzed, and some important properties are obtained. Simulations and experiments were carried out on a 7.5 kW four-phase SRM, and the results show that the ripple of the output torque is very low in spite of model-plant mismatches     

Power electronic converters for switched reluctance drives

A number of power electronic converter circuits exist for switched reluctance motor (SRM) drives which are generally applicable to most loads. A larger number of circuits exist which are suitable for particular niche applications, but which have the potential to be the most cost-effective within that niche. Due to the variable methods of operation of these circuits and the rapid progress in this field, comparisons of these circuits have so far been limited. This paper attempts to bring together the sum total of power converter topologies so far published for SRM drives. A novel classification methodology is presented. The power converters are compared using a straightforward total semiconductor VA per phase sum, and the relative cost of the drive system elements is considered     

Torque ripple minimization in switched reluctance motor drives byPWM current control

Higher torque ripple is one of the few drawbacks of switched reluctance motor (SRM) drives which otherwise possess excellent characteristics for applications in many commercial drives. This paper begins with an extensive review of torque ripple reduction methods that appear in the literature and then presents a new strategy of PWM current control for smooth operation of the drive. This method includes a current control strategy during commutation when torque ripple minimization is of utmost importance     

Inductance model-based sensorless control of the switched reluctance motor drive at low speed

A sensorless control scheme for the switched reluctance motor (SRM) drive at low speed is presented in this paper. The incremental inductance of each active phase is estimated using the terminal measurement of this phase. The estimated phase incremental inductance is compared to an analytical model, which represents the functional relationships between the phase incremental inductance, phase current, and rotor position, to estimate the rotor position. The presented sensorless control scheme requires neither extra hardware nor huge memory space for implementation. It can provide accurate rotor position information even as the magnetic characteristics of the SRM change due to aging. Combined with other inductance model-based sensorless control techniques, the proposed method can be used to develop an inductance model-based sensorless control scheme to run the SRM from standstill to high-speed. Simulation and experimental results are presented to verify the proposed scheme.     

Fuzzy logic rotor position estimation based switched reluctance motor DSP drive with accuracy enhancement

This paper describes a novel angle estimation scheme for a real time digital signal processor (DSP) based switched reluctance motor drive using fuzzy logic where several unique techniques are implemented to improve the estimation accuracy. First, an optimized fuzzy model of the motor was created using an adaptive neuro-fuzzy inference system (ANFIS) based on accurately measured flux linkage data. Secondly, an improved fuzzy optimal sensing phase selector was developed based on the analysis of both modeling error and measurement error. Lastly, a delayless polynomial predictive filter and an online phase winding resistance estimator are also implemented to further improve the position estimation accuracy. Both simulation and experiment results on a DSP based real time drive are presented to show the effectiveness of this scheme.     

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     

基于模糊PI控制的开关磁阻电机调速系统的MATLAB仿真

为改善开关磁阻电机（简称SRM ）的非线性特性问题,提高开关磁阻电机调速系统（简称SRD ）的响应特性和稳定性,对 SRD 采用双闭环控制,即速度外环和电流内环。其中速度外环采用模糊 PI 控制技术,借助 MATLAB/SIMULNK对系统进行建模和仿真。将其仿真结果与常规PI仿真结果进行分析比较。结果表明基于模糊PI控制的开关磁阻电机调速系统,响应速度提高了40%,超调量减小1.2%,调节精度和稳定性都大大提高,系统震荡也明显减小。     

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.     

无轴承开关磁阻电机无位移传感器运行研究

无轴承开关磁阻电机具有体积小,无磨损,效率高,功耗低等优点,但机械式传感器限制了电机固有高速性能的发挥。因此,文中研究了一种基于高频电压信号注入的无径向位移传感器控制方法,并建立了基于此算法的电机转子径向位移预测模型,实现无轴承开关磁阻电机无位移传感器稳定悬浮运行。最后,通过仿真和实验分析对所提方法进行了验证。结果表明,所设计控制策略能够正确估计出单绕组无轴承开关磁阻电机的转子径向位移,且系统具有较好的动态响应能力。     

基于虚拟仪器的开关磁阻电机监控系统

为了提高开关磁阻电机控制系统的实用性和可靠性,利用NI虚拟仪器构建了监控系统,可以实时监测和调整电机运行时的重要参数。该方案以装有数据采集卡的PC机和DSP作为硬件基础,利用LabVIEW软件将各类传感器传送的信号进行实时处理,同时记录和显示各项数据,然后再利用相应的算法完成对数据的分析。DSP则作为PC机故障时的备用系统。实验证明,该控制系统的实用性和可靠性比之前大大提高。     

A novel unipolar converter for switched reluctance motor

A configuration of a unipolar power converter with improved switching performance suitable for switched-reluctance motor supply is presented. The switched-reluctance motor operation principle is presented and its ideal characteristics are considered. The proposed converter is described and its operation is analyzed. The converter characteristics are studied with the aid of computer simulation. Current control of the proposed converter is considered. A prototype converter has been built to verify the analysis results and to validate the simulation. The design procedure is presented and experimental results which confirm the analysis are given and discussed