On-line instantaneous torque control of a switched reluctance motor based on co-energy control

An on-line instantaneous torque control technique for a switched reluctance motor operating in the saturation region is presented. The proposed methodology is realised via the control of the instantaneous output torque of each excited phase by regulating its associated co-energy to follow a co-energy profile. As the parameters of the feedback controller are independent of the motor parameters in the analysis of the co-energy control system with the proposed methodology, the design of the proposed controller is simple when compared to that for traditional current controllers. Smooth shaft torque is obtained by torque sharing among the active phases during commutation. Simulation and experimental results confirm that the highfrequency torque ripple is reduced using the proposed algorithm.     

Hybrid force/position control scheme for flexible joint robot with friction between and the end-effector and the environment

In this paper a novel adaptive-sliding mode control design is developed for trajectory tracking of a class of flexible robots. This control design uses a force/position controller for robots with flexible joints where the friction between the end effector and the environment is taken into account. For systematic reasons the controller is designed considering the rigid links subsystem and the flexible joints. The proposed control system, satisfies the stability of the two subsystems and cope with the uncertainty of the robot dynamics. The feedback for the flexible subsystem is based on the joint torque signal and estimation of the torque derivative which is provided by a nonlinear sliding observer. For the stability of the observer, it is assumed that the uncertainty of the observed system is bounded. A MRAC algorithm is used for the estimation of the friction forces at the contact point between the end effector and environment. Finally simulation results are given to demonstrate the effectiveness of the proposed controller.     

基于浸入与不变原理的电力系统混沌振荡分析与控制

针对电力系统中普遍存在的参数变化引起系统混沌振荡导致系统不稳定问题,提出了一种基于浸入与不变(immersion and invariance,Ⅰ&Ⅰ)原理的自适应反演滑模控制(adaptive backstepping sliding mode control,ABSMC)算法,以提高电力系统运行稳定性.首先,利用电...     

光电跟踪系统力矩波动的自抗扰控制

为解决光电跟踪伺服系统受电机力矩波动影响产生的速度波动问题,提出了一种改进的自抗扰控制策略进行力矩波动补偿。该算法主要由两部分组成:通过扩张状态观测器辨识出系统扰动,然后将该扰动前馈到系统控制量中去,构成复合校正系统;反馈通道中采用两参数的比例微分控制器,可以保证系统的稳定性和良好的动态特性。仿真分析和实验结果表明:与同等闭环控制带宽的PI控制器相比,自抗扰控制器可以提高系统对扰动力矩的抑制能力,采用自抗扰补偿时,速度误差的峰值由1.88%降低到0.65%,速度误差的均方根值由0.8%降低到0.2%。实验结果证明提出的方法能够有效降低电机力矩波动的影响,提高速度平稳性。     

Adaptive controller design for a synchronous reluctance motor drive system with direct torque control

The design and implementation of adaptive controllers for a sensorless synchronous reluctance drive system with direct torque control is proposed. Two adaptive control algorithms, which include adaptive backstepping control and model-reference adaptive control, are proposed to improve the performance of a sensorless direct torque control synchronous reluctance motor drive system. A digital signal processor, TMS320-C30, is used to execute the rotor position estimating technique and the adaptive control algorithms. The system shows good transient responses, good load disturbance responses and good tracking responses. Several experimental results validate the theoretical analysis. The advanced controller design for a sensorless synchronous reluctance motor drive with direct torque control is proposed.     

Optimisation techniques for a hysteresis current controller to minimise torque ripple in switched reluctance motors

The switched reluctance (SR) motor has many benefits owing to its low cost, simple design, rugged construction and comparatively high torque-to-mass ratio. Unlike DC and induction motors, the SR motor is intended to operate in deep magnetic saturation to increase the output power density. Because of the saturation effect and the variation of magnetic reluctance with respect to rotor position, all the relevant characteristics of the machine are highly non-linear functions of both rotor position and phase current. The ultimate outcome of all these non-linearities is that the generated torque contains significant ripples. The non-linearities in the SR motor have been extensively studied and many control strategies to reduce the generated torque ripples have been proposed in the literature. Modulation of phase current profile for generating torque in the SR motor with minimum ripples was the focus of most of the research. However, the main challenge to minimise the torque ripple is to design a current controller that is able to track the modulated phase current. In this work, new techniques to optimise the widely used hysteresis current controller are studied, and experimental verifications under closed-loop speed control with the modulated reference current data are presented. The experimental results indicate that the torque ripple is reduced to lie within 5% of the desired steady torque using the proposed optimisation techniques.     

DSP-based electric power assisted steering using BLDC motor

This paper introduces a design and implementation of electrically assisted power steering (EAS) using BLDC motor for a vehicle. The control architecture consists of two layers of control, namely the vehicle speed associated control and the torque assist control. In the higher level of control architecture, the vehicle speed controller works as an assistance level controller for the steering effort. In the lower level, the torque controller gives the effort level control. This has been realized by torque sensor and vehicle sensor interfaced in the DSP. For implementing in the system, a DSP-based BLDC motor controller with three-phase inverter module is specially designed using Hall-effect sensor feedback and a single dc-link current sensor. This work is implemented in a Light Commercial Vehicle having a recirculating ball type gear. This is for the first time (EAS) being implemented for this type of vehicle any where in the world. Generally, EAS having clutch to disconnect the motor in high speed or abnormal conditions from the gear box. In this implementation the motor is directly coupled to gearbox without clutch and all abnormalities are handled by the processor. This is implemented without modifying the vehicle supply system like changing the existing alternator or rating of the battery and using the existing sensors. The design is such a way that the feel of the driver assistance can be varied easily at any time. The performance of the control system is experimentally verified and it is tested in one of the Light Commercial Vehicle (LCV).     

Adaptive Fuzzy Logic Controller for Harmonics Mitigation Using Particle Swarm Optimization

An excessive use of non-linear devices in industry results in current harmonics that degrades the power quality with an unfavorable effect on power system performance. In this research, a novel control technique-based Hybrid-Active Power-Filter (HAPF) is implemented for reactive power compensation and harmonic current component for balanced load by improving the Power-Factor (PF) and Total–Hormonic Distortion (THD) and the performance of a system. This work proposed a soft-computing technique based on Particle Swarm-Optimization (PSO) and Adaptive Fuzzy technique to avoid the phase delays caused by conventional control methods. Moreover, the control algorithms are implemented for an instantaneous reactive and active current (I_d-I_q) and power theory (Pq0) in SIMULINK. To prevent the degradation effect of disturbances on the system's performance, PS0-PI is applied in the inner loop which generate a required dc link-voltage. Additionally, a comparative analysis of both techniques has been presented to evaluate and validate the performance under balanced load conditions. The presented result concludes that the Adaptive Fuzzy PI controller performs better due to the non-linearity and robustness of the system. Therefore, the gains taken from a tuning of the PSO based PI controller optimized with Fuzzy Logic Controller (FLC) are optimal that will detect reactive power and harmonics much faster and accurately. The proposed hybrid technique minimizes distortion by selecting appropriate switching pulses for VSI (Voltage Source Inverter), and thus the simulation has been taken in SIMULINK/MATLAB. The proposed technique gives better tracking performance and robustness for reactive power compensation and harmonics mitigation. As a result of the comparison, it can be concluded that the PSO-based Adaptive Fuzzy PI system produces accurate results with the lower THD and a power factor closer to unity than other techniques.     

非线性系统的自适应可拓控制器设计

探讨可拓控制器的设计方法,利用自适应控制的设计策略来修正可拓控制器的增益参数,以近似获得所期望的最佳控制。所提出的控制器结构仅需调整单一参数,故易于实现。另外,引入最大值控制以保证所设计的可拓控制系统的稳定性,并将该控制器应用在非线性系统的控制上,以验证它的有效性及控制能力。     

电动转向系统稳定性能与抗干扰性能的研究

对电动转向系统的稳定性进行了研究．分析了路面激励干扰、传感器噪声对系统性能的影响，并将传统的PD控制算法和H∞控制理论相结合．应用于转向控制系统的研究，设计了控制器。计算机仿真结果证明，所设计的电动转向系统具有良好的稳定性、能够有效地抑制路面高频激励干扰和转矩传感器测量噪声对系统的影响。     

Optimization of Adaptive Fuzzy Controller for Maximum Power Point Tracking Using Whale Algorithm

The advantage of fuzzy controllers in working with inaccurate and nonlinear inputs is that there is no need for an accurate mathematical model and fast convergence and minimal fluctuations in the maximum power point detector. The capability of online fuzzy tracking systems is maximum power, resistance to radiation and temperature changes, and no need for external sensors to measure radiation intensity and temperature. However, the most important issue is the constant changes in the amount of sunlight that cause the maximum power point to be constantly changing. The controller used in the maximum power point tracking (MPPT) circuit must be able to adapt to the new radiation conditions. Therefore, in this paper, to more accurately track the maximum power point of the solar system and receive more electrical power at its output, an adaptive fuzzy control was proposed, the parameters of which are optimized by the whale algorithm. The studies have repeated under different irradiation conditions and the proposed controller performance has been compared with perturb and observe algorithm (P&O) method, which is a practical and high-performance method. To evaluate the performance of the proposed algorithm, the particle swarm algorithm optimized the adaptive fuzzy controller. The simulation results show that the adaptive fuzzy control system performs better than the P&O tracking system. Higher accuracy and consequently more production power at the output of the solar panel is one of the salient features of the proposed control method, which distinguishes it from other methods. On the other hand, the adaptive fuzzy controller optimized by the whale algorithm has been able to perform relatively better than the controller designed by the particle swarm algorithm, which confirms the higher accuracy of the proposed algorithm.     

Harmonics reduction in standalone DFIG-DC system by shunt active filter controlled in stator flux reference frame

The presence of diode rectifier in standalone Doubly Fed Induction Generator-Direct Current (DFIG-DC) system leads to considerable current, voltage and torque harmonics and requires reactive power from the machine. A unique shunt active filter arrangement is proposed for addressing these requirements. The DC Link of DFIG-DC itself acts as input to shunt active filter and there is no requirement of creating and regulating a separate one. Since the stator flux reference frame is known in FOC of DFIG-DC system; the same can be used as PLL for the generation of current references for harmonics and reactive compensation in active filter control scheme. Hence, the AC voltage sensing is not needed in the proposed active filter control. In this paper, it is shown that current, voltage and torque harmonics are reduced with the help of shunt active filter, which have lower rating compared to the rotor side converter. The proposed scheme is verified by detailed experiments on a 5.5 kW slip-ring induction machine.     

直接驱动系统功率驱动电源的设计和新型控制技术的研究

对直接驱动变磁阻电机用功率驱动电源进行了设计,并给出了一种新型的此类电机的控制策略,设计了一种非线性转矩控制表,并给出制表的步骤,速度调节器采用变结构控制加以高速时的超前角控制,实验结果表明,使用该控制策略,拓宽电机的调速范围,快速性有很大程度的提高。     

Implementation of modified chaotic invasive weed optimization algorithm for optimizing the PID controller of the biped robot

The present research work involves the implementation of Modified Chaotic Invasive Weed Optimization (MCIWO) algorithm for optimizing the gains of torque based proportional integral and derivative (PID) controller used to control the motors of the biped robot while walking on flat surface. While designing the controller, the dynamics of the biped robot has been derived using the well-known Lagrange-Euler (L-E) formulation. Subsequently, manual tuning procedure is employed to find the ranges of the gains of PID controller used in the developed algorithm. Once it is optimized, the effectiveness of the proposed algorithm is then compared with the Differential Evolution (DE) algorithm, in terms of variation of error, torque required, zero moment point (ZMP) and dynamic balance margin (DBM) of the biped robot. It has been observed that the MCIWO algorithm tuned PID controller is found to perform better than DE tuned controller. Further, the optimal gait obtained through the developed algorithm is validated by executing it on the real robot. It has been observed that the robot has successfully negotiated the flat terrain with the gaits obtained by the optimal PID controller.     

Design and implementation of FPGA-based phase modulation control for series resonant inverters

Owing to the tremendous advances in the digital technology, and improved reliability and performance of the digital control mechanisms, this paper focuses on design and implementation of digital controller using FPGA-based circuit design approach. The digital controller proposed is designed for series resonant inverter used in DC-DC converter applications. Phase modulation technique is proposed for the realization of digital controller on FPGA. The Series Resonant Converter (SRC) is considered in this paper as a preferred converter topology for high power, high voltage power supplies. This paper studies the implementation of phase shift modulation technique using FPGA. The inverter designed, is IGBT based, and Zero Voltage Switching (ZVS) technique is implemented due to reduced stresses on devices and increased efficiency. The phase modulated series resonant inverters (PM-SRC) promotes ZVS operation when its switching frequency is greater than resonant frequency. The designed PM controller is realized using FPGA on which control algorithm and other features of a controller are developed. The series resonant inverter is built and tested for full load under open loop and closed loop conditions at a switching frequency of 20 kHz. The results are presented under varying load conditions. The simulation and the experimental results were found to match closely.     

基于混合灵敏度方法的EPAS系统控制研究

建立汽车模型和EPAS系统动力学模型,针对EPAS系统中存在的传感器噪声和路面干扰等难题,将基于混合灵敏度设计方法的H∞鲁棒控制理论应用于汽车EPAS系统的控制研究,设计混合灵敏度H∞鲁棒控制器,并与PID控制器进行仿真比较。仿真结果表明,采用H∞控制器能有效地抑制传感器噪声和路面干扰,提高了系统的抗干扰性能,增强了系统的鲁棒性。     

Intelligent controlled shunt active power filter for voltage and current harmonic compensation in microgrid system

An integrated microgrid with a novel shunt active power filter (APF) using Elman neural network (ENN) is proposed in this study. The microgrid consists of a storage system, a photovoltaic (PV) system, the shunt APF, a linear load, and a nonlinear load. Moreover, the master/slave control algorithm is adopted in the microgrid. The storage system, which is considered as the master unit, is adopted to control the active and reactive power outputs (P/Q control) in grid-connected mode and the voltage and frequency of the microgrid (V/f control) in islanded mode. Furthermore, the PV system is considered as the slave unit to implement P/Q control in both grid-connected and islanded modes. In addition, the proposed shunt APF possesses dual functions of voltage and current harmonic compensation for microgrid under voltage harmonic propagation and nonlinear load to reduce the voltage and current total harmonic distortions (THD) effectively. Additionally, an ENN controller is adopted in the proposed shunt APF to improve the transient and steady-state responses of DC-link voltage during the switching between the grid-connected mode and islanded mode. Finally, some simulation results are provided to verify the feasibility and the effectiveness of the integrated microgrid with the intelligent controlled shunt APF.     

Small-signal dynamic model of a micro-grid including conventional and electronically interfaced distributed resources

A systematic approach to small-signal modelling of a micro-grid system that includes conventional (rotating machine) and electronically interfaced distributed resource (DR) units is presented here. The proposed approach incorporates fundamental frequency deviations in the overall system model and provides a methodology for the analysis of autonomous micro-grid, which inherently is more prone to frequency changes than the conventional utility grid. The model represents (i) electro-mechanical dynamics of the synchronous machine including the exciter and the governor systems, (ii) dynamics of the voltage-sourced converter and its real/reactive power controllers and (iii) the network dynamics. The model is intended for the controller design/optimisation, evaluation of angle/voltage stability, investigation of torsional dynamics, controller interactions of electronically interfaced DR units and low-frequency power quality issues. Typical results from application of the proposed modelling approach to a study system are presented. The results are qualitatively verified on the basis of the comparison with those obtained from time-domain simulation in the PSCAD/EMTDC environment     

Direct torque and flux control of an IPM synchronous motor drive using a backstepping approach

A novel direct torque and flux controlled interior permanent magnet synchronous motor (IPMSM) drive using an adaptive backstepping technique is presented. Closed-loop regulation of the speed, torque and stator flux linkage is achieved by a non-linear controller. Using Lyapunov analysis, the stability of the controller is guaranteed. The reference voltage vectors are generated by a space vector modulation (SVM) unit, which replaces the switching table in the conventional direct torque control (DTC) scheme. While retaining its main advantages, the proposed backstepping controller features reduced torque and flux ripples as compared to the classical DTC. On the one hand, a comparison with the proportional-integral (PI) direct torque and flux control (DTFC) scheme shows that the proposed approach is superior. Experimental results confirm the effectiveness of the proposed method.     

A Study on a Wire Tension Adaptive Control System of a Multi-wire Saw in Computer Simulation

Based on the analysis of the mechanism of wire tension control by using torque motors in the multi-wire saw machining process,some mathematical models of a tension control system are studied,and an adaptive algorithm is designed for controlling the wire tension.In this algorithm of tension control,the rotation speeds and waving angle of motors are measured and fed back to the controller,and the NLMS(normalized least mean squares) algorithm is used to calculate the adaptive correction value and control the w...