This paper deals with robust control problems for double-pendulum overhead cranes. For this reason, a linearized and decoupled double-pendulum overhead crane dynamic model is derived by adopting a disturbance observer and modal analysis technology. Next, a robust linear feedback controller, whose gains are obtained via LMI optimization method, is proposed. Finally, numerical simulations validate that the proposed method has superior control performance.

Magnetic bearings have been used in flywheel energy storage systems to improve their performance because these kinds of bearings can provide non-contact supporting so that the friction between the rotor and the bearings is reduced significantly. However, the gyroscopic coupling, parameter coupling, and imbalance force affect the operating performance and stability of a magnetic suspended flywheel energy storage system with asymmetric rotor; therefore, the main purpose of this study is to propose a control method for achieving decoupling and stable operation of the aforementioned system. To this end, after deriving the mathematical model of a radial 4-degree-of-freedom rotor–bearing system, a novel cross-feedback-based modal decoupling controller is designed for vibration suppression caused by gyroscopic coupling, parameter coupling, and imbalance force. Better performance is obtained through comparing the decoupling performance, control performance, and disturbance rejection performance with a traditional decentralized proportional–integral–derivative controller and a cross-feedback controller via ADAMS–MATLAB co-simulation technology and experimental results.

In this paper, a newmagnetic field modulation type of brushless double-fed (MFM-BDF) machine is proposed, in which a split-pole structure inner stator with three modulating poles on each stator tooth and an outer rotor with surface-mounted permanent magnets are adopted. By employing a set of 3-phase armature winding and a set of 3-phase field winding wound around stator teeth and modulating poles, respectively, the hybrid excitation operation can be achieved. The proposed machine can achieve not only a high torque density due to the magnetic field modulation effect, but also an wide operation region and an almost unchanged cogging torque peak-to-peak value by feeding flux-weakening and flux-enhancing currents into the field windings, respectively. The configuration of proposed machine and the basic principle are introduced first. Then by using 2-dimension finite element analysis, the basic characteristics, such as no-load flux linkage, cogging torque and no-load EMF are analyzed.

Optimizing the structure of stator and rotor can efficiently improve the performances of motor.Due to the fact that the novel axial flux doubly salient pole permanent magnet motor(AFDSPM) has the inner and outer of stator and rotor,traditional optimization method for improving the performance is of limited efficiency.Based on the magnetic circuit method,two formulas of flux and cogging torque with respect to reluctance and magnetic density were obtained.Meanwhile,the optimization method of the inner and outer of stator and rotor with unequal height was proposed.Then,the finite element method was employed to analyze and verify the above strategy.According the simulation results of the electromagnetic characteristics of the optimized motor,the effectiveness of the developed approach was verified.This method provides a novel direction to optimize the axial flux motor.

When the hook mass is larger than the load mass or the load has distributed mass property, the load sway of the crane system presents as double-pendulum effect. In this situation, crane system has two different natural frequencies so that the sway characteristic becomes more complex and greatly increases the difficulty of the dynamic performance analysis and controller design. In order to solve the aforementioned problems, the linear dynamics of a 2-D overhead crane with double-pendulum effect is derived based on a disturbance observer, and is decoupled for controller design by modal analysis. Next, an S-shaped curve which is widely used in industrial applications is generated on the basis of the decoupled linear crane model for suppressing residual double-pendulum load sway. Parameters of the trajectory can be easily obtained by calculating algebraic equations. Finally, simulation results validate the effectiveness of the proposed method.

Magnetic bearings have been used in flywheel energy storage systems for improving their performance due to the main advantage of contact-free operation. However, the gyroscopic coupling, parameter coupling and imbalance force affect the operating performance and stability of an magnetic suspended flywheel energy storage system with asymmetric rotor, therefore, a cross feedback based control method is proposed. Firstly, the dynamic model of a radial four-degree-of-freedom active magnetic bearing rotor system is derived. Next, a novel cross feedback-based modal decoupling controller is designed for vibration suppression caused by gyroscopic coupling, parameter coupling and imbalance force. Better performance is obtained through comparing the decoupling performance, control performance and disturbance rejection performance with a traditional decentralized PID and a cross feedback controller.

以三相电压型逆变器为研究对象,介绍了多种空间矢量调制方法.该方法易于数字化,避免繁琐的计算.本文通过一种在标准正弦波的基础上,注入零序分量来统一给出这些调制方法.逆变器在这些调制方法下的输出电压中包含各次谐波.本文在谐波磁通的基础上对其深入分析.得出谐波磁通和各影响参数之间的关系,并找出最小谐波磁通的方法.最后给出了输出电压的频谱图,验证了分析结论.

Based on the torque sharing function ( TSF) , the method of indirect torque control and mathematical models for switched reluctance motor ( SRM) were introduced to solve the problem of torque ripple, in addition, cross feedback was introduced to improve the structure of the proposed system. And then, the simulation research of torque ripple minimization for SRM based on indirect torque control system was completed by MATLAB/Simulink software. Simulation results showed that torque of each phase could be shared reasonably by TSF, and that reference current could be achieved by torque inverse model, which could keep real-time tracking of current and effectively suppress torque ripple of SRM, but also has improved the ability of online learning for TSF.

The switched reluctance motor ( SRM) in the high-speed operation of the torque ripple suppression performance was poor, limited range of speed regulation, analyzed the operation of high-speed switched reluctance motor torque characteristics and current compensation of torque ripple suppression effects of poor, designed the cross compensation type torque distribution function ( TSF) , and the implementation of direct torque control for each phase of the actual torque to the desired torque tracking, the motor could output constant torque under high-speed operation. The simulation results showed that the torque control system of SRM based on cross compensation torque distribution function had faster response speed and wider speed range.

永磁同步电机(PMSM)在有感控制方案中需安装编码器或霍尔传感器,增加了系统的设计成本,因此,研究PMSM的无感控制方案就显得有必要性.随着现代控制理论的发展,无传感器技术也日益发展.以磁场定向控制为控制策略,以模型参考自适应理论为基础,设计了一种速度观测器.侧重用现代控制理论知识分析了观测器的稳定性,并用传统控制理论知识分析了一种新的观测器中PI调节器参数整定方法.这种方法具有很强的适应性和移植性.最后,验证了这种方法的准确性和可行性.

This paper presents a backstepping control method with speed estimation of permanent magnet synchronous motor (PMSM) based on model reference adaptive system (MRAS). First, a comprehensive dynamical model of PMSM in d–q axis and its space state equations are established. Next, using Lyapunov stability theorem, based on the backstepping control theory, the PMSM rotor speed and current backstepping controllers are designed. Furthermore, using Popov stability theory, based on MRAS, the PMSM rotor speed observer is designed. Finally, Matlab/Simulink simulation results show that the backstepping control and speed observer are effective and feasible.

In the control of the rotary crane, it is important to consider the trade-off between the boom positioning characteristics and the sway of the load. However, it seems difficult to obtain good control performance in both of them using 1-degree-of-freedom control approach. Therefore, a robust 2-degree-of-freedom control approach is proposed in this article. First, a linear dynamic model of a rotary crane is derived using a disturbance observer. Next, a state feedback controller with integrator is designed based on the model, and controller gains are determined by using linear matrix inequality optimization for achieving robustness with respect to rope length variance. Then, a feedforward controller is designed by solving an optimal regulator problem based on the model of closed-loop system for improving the boom positioning characteristics of the crane. Finally, the experimental results confirm the effectiveness of the proposed method. Hence, the crane can be easily operated without sensor systems for measuring rope length, and consequently, the structure of the crane can be simplified and implementation cost can be reduced.

PWM逆变器在直接驱动电机时会产生较高的共模电压,并且逆变器的输出电压中含有大量的差模电压谐波分量.这对于电机系统来说是负面效应.首先介绍了一种新的脉宽调制方法(NSPWM),该方法可以抑制共模电压.其次,在逆变器的输出端提出一种LC滤波器的拓扑结构.该方法可以有效地滤除相电压的高次谐波,从而消除了差模电压的谐波分量,并且在很大程度上抑制了共模电压.

In order to realize the self?location of the indoor mobile robot,a mobile robot location system based on monocu?lar vision was designed in consideration of the indoor complexity and environment feature. The landmark combining color and shape is taken as the robot feature in the indoor environment with the ceiling landmark information. The color image segmenta?tion and contour matching method is used to recognize the landmark by means of the camera whose head is vertical to the cei?ling,so as to analyze the world coordinate information of the landmark,and calculate the global position and azimuth angle of the robot. This method can improve the speed of image processing and feature extraction greatly. The experimental results show this method can satisfy the requirements of system real?time performance and robustness.

This paper deals with the permanent magnet synchronous motor (PMSM) speed estimation and parameters identification problems. It proposes a solution to estimate speed and identify stator resistance, d-axis and q-axis inductance simultaneously. In fact, there are a lot of methods for estimating the speed, for example high-frequency injection, Kalman filter, and model reference adaptive system (MRAS). However, with the PMSM running, some parameters will change such as the stator resistance will change with the increase in temperature. These parameters are useful for estimating the speed. So, it is necessary to identify parameters simultaneously to adapt to the changes of these parameters. In this paper, MRAS is the theoretical basis. First, the adaptive law of speed observer is constructed through Popov stability. Then, the adaptive laws of stator resistance, d-axis, and q-axis inductance are constructed through Lyapunov stability. The stability of the proposed observers is also discussed. Last, this paper uses field-oriented control strategy and illustrates the obtained results through simulation and experiment.

Considered the characteristics of switched reluctance motors,the mathematical model of motors was established.The theory of motor working and the relationship among phase current,flux and position angle was analyzed.In the Matlab /Simulink,the model of switched reluctance motor drive system was built. And the influence that voltage and breaking angle affect the motor speed,torque,current was analyzed.The system of current and speed double loop was established based on the simulation analysis,and comparing with current chopper speed control system.Simulation results show the current and speed double loop system has advantages,such as rapid start,small ripple and stability,which is more suitable for controlling the speed of the switched reluctance motor.

A new type of axial flux permanent magnet generator with doubly salient structure was proposed. By means of magnetic circuit method and finite element method,parameters of the new generator were obtained,including size of stators,rotors and magnet,numbers of windings,etc.The newly proposed generator was analyzed by FEM.Field distributions,linkage and other characteristics with different rotor positions in no -load operations were achieved.The simulation testifies that,in accord with theoretical analysis,the newly designed generator with characteristics of both doubly salient motors and axial flux motors is practical.

This paper proposed a novel method which is the combination of traditional cross feedback control and sliding mode control for the problem of gyroscopic coupling and imbalance disturbance in the rotor system of magnetic suspended wind turbines when they rotate under high speed situation. Firstly, the mathematical model of a radial four-degree-of-freedom active magnetic bearing rotor system is derived. Then, a sliding mode controller is designed after decoupling the model by using cross feedback control method. The stability of the whole system is guaranteed by the Lyapunov stability theory. Better robustness and regulation performance is obtained through comparing with a traditional decentralized PID-based cross feedback controller numerically.

In high performance AC system, whether the flux position can be obtained correctly or not will influence the dynamic and steady state performance. Induction motor full model realizes motor speed on-line identification as the parameter, besides motor current and flux real-time observation as state variables simultaneously. Research is done on the convergence characteristics of flux observation in the process of estimating motor parameters and variables. Due to the nonlinearities of full model, singularity theory is adopted, dividing full model into speed identification model and flux observation model, with the two models separated on time scale. By analyzing the eigenvalue distribution and damp ratio of flux observation subsystem, convergence and influence factors are studied. Research results show that the damp ratio in the middle and high speed range needs to be improved and the corresponding strategy of improving convergence is proposed. Simulation and experiments verify the validity of analysis method and the feasibility of proposed strategy.

Stability of full order flux observer based speed sensorless control system is studied in the paper. By small signal analysis method, the whole control system is linearized and transfer function from speed reference to practical speed is obtained. Examining pole distribution of transfer function, stability analysis is carried out. The impact of motor parameter error on speed identification system is considered. Besides, research is made on the relation between lowering bandwidth of speed identification loop and control loop and improving speed sensorless control system stability. Simulation and experiment results validate the analysis in the paper.