西门子变频器的应用 第2讲 MM440变频器在电梯控制中的应用

电梯是随着高层建筑的兴建而发展起来的一种垂直运输工具,其要求安全性、舒适性和经济性。在多年的实践之后,变频调速已经成为了电梯传动的主要控制方式。本文主要阐述了MM440变频器在电梯控制中的应用。     

Design and implementation of a new modified sliding mode controller for grid-connected inverter to controlling the voltage and frequency

As the output power of a microgrid with renewable energy sources should be regulated based on the grid conditions, using robust controllers to share and balance the power in order to regulate the voltage and frequency of microgrid is critical. Therefore a proper control system is necessary for updating the reference signals and determining the proportion of each inverter in the microgrid control. This paper proposes a new adaptive method which is robust while the conditions are changing. This controller is based on a modified sliding mode controller which provides adapting conditions in linear and nonlinear loads. The performance of the proposed method is validated by representing the simulation results and experimental lab results.     

Iron Loss Analysis of Permanent Magnet Motors Fed by PWM Inverter

Carrier harmonic losses that consist of iron loss, eddy current loss, and ac copper loss are produced in a permanent magnet machine driven by a PWM inverter. It is already known that a higher motor inductance can lead to lower carrier harmonic losses. This paper investigates the carrier harmonic loss composition of two motors with identical dimensions but different inductances. The results of finite element analysis (FEA) showed that the eddy current loss in the iron core accounts for most of the carrier harmonic loss. It is also shown that the carrier harmonic loss of the iron core is quantifiable using theoretical calculations.     

Power supply for generating frequency-variable resonant magnetic perturbations on the J-TEXT tokamak

To further research the response of the tearing mode(TM) to dynamic resonant magnetic perturbation(DRMP) on the J-TEXT tokamak, a modified series resonant inverter power supply(MSRIPS) with a function of discrete variable frequency is designed for DRMP coils in this study. The MSRIPS is an AC–DC–AC converter, including a phase-controlled rectifier, an LC filter, an insulated gate bipolar transistor(IGBT) full bridge, a matching transformer, three resonant capacitors with different capacitance values, and three corresponding silicon controlled rectifier(SCR) switches. The function of discrete variable frequency is realized by switching over different resonant capacitors with corresponding SCR switches while matching the corresponding driving frequency of the IGBT full bridge. A detailed switching strategy of the SCR switch is put forward to obtain sinusoidal current waveform and realize current waveform smooth transition during frequency conversion. In addition, a resistor and thyristor bleeder is designed to protect the SCR switch from overvoltage. Manufacturing of the MSRIPS is completed, and the MSRIPS equipment can output current with an amplitude of 1.5 kA when its working frequency jumps among different frequencies. Moreover, the current waveform is sinusoidal and can smoothly transition during frequency conversion. Furthermore, the transition time when the current amplitude rises from zero to a steady state is less than 2 ms during frequency conversion. By using the MSRIPS, the expected discrete variable frequency DRMP is generated, and the phenomenon of the TM being locked to the discrete variable frequency DRMP is observed on the J-TEXT tokamak.     

Control principles of micro-source invertersused in microgrid

Since micro-sources are mostly interfaced to microgrid by power inverters, this paper gives an insight of the control methods of the micro-source inverters by reviewing some recent documents. Firstly, the basic principles of different inverter control methods are illustrated by analyzing the electrical circuits and control loops. Then, the main problems and some typical improved schemes of the ωU-droop grid-supporting inverter are presented. In results and discussion part, the comparison of different kinds of inverters is presented and some notable research points is discussed. It is concluded that the most promising control method should be the ωU-droop control, and it is meaningful to study the performance improvement methods under realistic operation conditions in the future work.     

高压变频器在600MW机组引风机的应用

就大容量高压变频器在600MW机组引风机的应用进行综合分析。从高压变频器的结构组成、性能指标分析及现场安装调试进行详细阐述,并对改造后的节能进行客观分析评价。结合运行实际,分析了高压变频器运行后对风机本体的影响及存在问题,有针对性地提出防范措施。     

变频调速共直流母线在Ф1270拉丝机上的应用

介绍了变频调速共直流母线在Ф1270直进式拉丝机上的应用。通过对拉丝机制动工作的分析。充分利用较先进整流单元和逆变器的特性构成直流母线系统来作为大功率拉丝机的传动系统。在减少拉丝机变频调速对电网的干扰,提高电网的电能质量以及减少设备投入、节能方面有特别重要的意义。     

翻车机系统中谐波的治理策略

本文通过对谐波及其危害性的阐述,明确了谐波治理的重要意义,并列举了当前的主要的治理方法：并结合翻车机系统中谐波治理的案例,通过分析系统中谐波产生的原因和采取的相关治理方法,强调设备安装阶段遵守电磁兼容安装规范的重要性。     

数字化三相大功率逆变波形内模控制方法

针对三相逆变电源数学模型在旋转αβ坐标系下的特点,提出了基于神经网络内模原理的逆变波形控制方案.用神经网络预估器作为逆变器的内部模型,用神经网络辨识预估逆变器正模型及其逆模型,在线修正、补偿内部模型与被控逆变器之间的模型失配.仿真和实验结果表明,该方案控制下系统稳压精度高,有较快的动态响应.     

SB60型变频器应用于风机控制变频调速系统

在工矿企业中,风机设备应用广泛,可应用于锅炉燃烧系统、通风系统和烘干系统等.变频器的运行控制方式采用U/f控制方式.变频器外部FWD控制模式,选择X4、X5端子控制端子的通断实现变频器的升降速,变频器一旦发生故障,风机由变频运行切换为工频运行的控制,从而实现风机工频运行.