排序方式： 共有126条查询结果，搜索用时 15 毫秒
101.
This paper presents an investigation of inverter fault-tolerant operation for a permanent magnet synchronous motor （PMSM） direct torque control （DTC） system under various inverter faults. The performance of a faulty standard 6-switch inverter driven PMSM DTC system is analyzed. To avoid the loss or even disaster caused by the inverter faults, a topology-modified inverter with fault-tolerant capability is introduced, which is reconfigured as a 3-phase 4-switch inverter. The modeling of the 4-switch inverter is then analyzed and a novel DTC strategy with a unique nonlinear perpendicular flux observer and feedback compensation scheme is proposed for obtaining a continuous, disturbance-flee drive system. The simulation and experimental results demonstrate that the proposed inverter fault-tolerant PMSM DTC system is able to operate stably and continuously with acceptable static and pretty good dynamic performance. 相似文献
102.
Because brushless direct current (BLDC) motors have the advantages of a compact size, high power density, high efficiency, and long operating life time, they are widely used in many industrial products and electric traction systems. It is known that the BLDC motors have no brushes for commutation. They are commutated with electronically commutation. So, the rotor position information of the BLDC motors must be known to understand which winding will be energized according to the energizing sequence. In most of the existing BLDC motor drivers, rotor position information is detected by Hall effect sensors. This kind of mechanical position sensors will bring additional connections and costs, reliability decrease and noise increase. In order to improve the control performance and extend the range of speed regulation for BLDC motors, a position sensorless control method is proposed in this paper. In the proposed control method, rotor position information of the BLDC motors is detected from the back electromagnetic forces (back-EMFs) which are estimated by an unknown-input observer with line to line currents and line to line voltages. For the purpose of verifying the effectiveness of the proposed control method, a model is built and simulated on the Matlab/Simulink platform. The simulation results show that the speed regulation performance of BLDC motors is improved compared with using Hall effect sensors. At the same time, the reliability of the BLDC motors is improved and the costs of them are reduced because the position sensor is eliminated. 相似文献
103.
曹庆生 《武汉工程职业技术学院学报》2011,23(1):33-38
使用蓄电池储存太阳能,设计一高频变换电路提升为320V直流高压,经过SPWM逆变形成50Hz正弦交流电。对二次变换的缘由、逆变电路的构成、高频变压器的设计计算、SPWM芯片及驱动程序、H桥逆变电路的工作原理作了详细介绍。 相似文献
104.
本文提出了一个新颖的结实型谐振直流环节软开关静止变流器拓扑,对直流环节的软开关工作原理和脉宽调制控制策略进行了详细分析,讨论了逆变桥的离散脉冲控制策略,分析了变流器的工作特性,并通过试验进行了验证.,A novel resonant dc link soft-switching static inverter topology is presented. The soft-switching operation principle and pulse width modulation control feature of dc link is analyzed in detail. The discrete pulse control strategy of inverter bridge is discussed. The operation characteristics of inverter are analyzed and verified by experiment. 相似文献
105.
为了便于修改剪切长度和提高剪切精度,提出了一种基于可编程控制器的铜板定长剪切生产线PLC控制系统,并对控制系统的硬件结构和软件组成进行了分析。该系统应用可编程显示器设置剪切长度,采用光电编码器测量钢板长度,采用变频器进行定位控制。生产实践表明,位置控制误差在±1mm以内,同时具有效率高、运行可靠、人机交互友好的特点。 相似文献
106.
为限制级联多电平逆变器输出电压谐波,提出一种改进粒子群优化(PSO)算法.在考虑三倍次谐波的情况下,给出最优化阶梯波法的目标函数.粒子群优化算法的惯性权重按负反正切规律变化,加速常数按反正切规律变化.通过提高算法前期全局探索能力和后期局部开发能力,算法搜索能力增强,而算法计算量几乎未增加.分析该方法的参数范围和粒子轨迹收敛速度,并将该方法应用于十一电平逆变器谐波限制问题,获得较佳的开关角设置方案,表明该方法具有优良的收敛性能。 相似文献
107.
为使Z源逆变器的升压因子独立于调制度,同时不增加输出电压谐波,提出一种三载波脉冲宽度调制(Pulse Width Modulation,PWM)策略.该方法通过3个载波与三相调制信号比较控制各功率器件,直通零状态仅在传统零矢量作用时间内加入,不改变输出电压波形.在一定的调制度下,电压增益由载波的直流偏置电压决定.通过对该调制策略下的电容电压应力、功率器件电压应力与其他传统方法进行分析比较,并对Z源逆变器和改进Z源逆变器进行仿真,结果表明该方法具有良好的控制性能. 相似文献
108.
变频器在日常生活中的应用已经随处可见,但很多人对它的认识就只是变频而已。事实上,它在改变频率的同时还具有一定保护功能。了解各类变频器的保护功能,对于正确使用变频器及故障的排查非常重要。本文主要详细介绍变频器在运行过程中的过电流保护功能、过载保护功能、过电压保护功能、欠电压的保护功能。 相似文献
109.
许胜辉 《武汉职业技术学院学报》2013,12(1):84-89
针对风力发电并网的优化问题。提出了三相电压源脉冲宽度调制（PWM）逆变器的定向矢量控制技术,并设计了数字控制的变换器一逆变器系统。给出了该变换器和逆变器的数学模型。提出了一种定向矢量控制的方案来实现对风能并网的控制策略。为了检验该系统的动态性能。采用MATLAB7／SIMULINK程序进行了仿真。仿真结果表明,提出的控制系统模型在不同的干扰下都展现出其良好的性能。 相似文献
110.
The effects of parasitic capacitance in induction motor system are unnoticed when it is fed from the AC line,but they are obvious when supplied directly from a PWM inverter,Consequently,many parasitic problems occur.Such as motor-to-earth leakage current.Bearing current.incoming line current distortion and uneven distribution of electrical stresses along the winding.On the basis of the uniform transmission line principle.a complete equivalent circuit of the PWM inverter-fed motor system is presented,based on which all the capacitive parasitic problems mentioned obove are analyzed and simulated by means of PSPICE.All the results are consistent with the existing ones. 相似文献