基于降阶谐振控制器的三相逆变器电压控制研究

在电力行业中,电压型三相逆变器是电力系统能够正常稳定运行的重要设备,对能源转换的可靠性与有效性具有极其重要的作用,因此,三相逆变器电压控制技术受到世界各国专业学者的关注与研究。三相逆变器的输出端搭载非线性负载时容易受到谐波因素干扰,进而影响到输出电压的质量,而在三相逆变器中搭载降阶谐振控制装置能够有效解决这一问题。基于此,本文对降阶谐振控制器与三相逆变器的原理进行简单分析,利用仿真模拟试验的方法验证降阶谐振控制器在电力系统中的实际作用,以此研究基于降阶谐振控制器的三相逆变器电压控制。     

基于移相谐振PWM控制器的电阻点焊逆变器

逆变主电路是逆变点焊系统的重要组成部分,为了对全桥逆变电路实现PWM移相控制,本文采用移相谐振PWM控制芯片UCC3895,通过设置其外围电路,产生两组四路PWM波形,经桥式驱动芯片IR2110放大,驱动逆变主电路.通过试验,实现了UCC3895和IR2110芯片外围电路中各关键参数的优化,电路输出为占空比可调的正负交变脉冲.     

采用重复控制技术的逆变器仿真研究

本文介绍了重复控制器的基本原理 ,详述了重复控制器中各参数的设计过程 ,并通过仿真分析 ,阐述各参数选择依据 ,以及它们对系统稳态误差和收敛速度的影响     

基于根轨迹的单相逆变器PID控制器设计

如果PID控制器参数设计不良,控制器不能发挥优良调节作用,使逆变器单环控制系统不能实现理想的性能.结合传统控制理论,提出了一种基于根轨迹配置的单向逆变器的PID参数设计方法.该方法与一般的PID参数设计方法相比,具有简单快捷、直观实用等优点.仿真和实验结果有效地验证了理论分析.     

基于改进遗传算法的高压直流输电系统逆变器定电压自抗扰控制器的设计

换流站中整流器和逆变器具有良好的控制性能是HVDC系统安全稳定运行的保证.自抗扰控制器(ADRC)对系统时变和不确定性干扰具有良好适应能力,但参数不易整定.本文将一种综合考虑控制器动态性能和被控对象输入受限的改进遗传算法应用到ADRC的参数整定中.将其应用到直流输电系统的逆变器控制器的设计中,仿真结果表明所设计的逆变器定电压自抗扰控制器具有良好的控制性能,对系统的外扰和模型参数的摄动具有良好的适应性.     

自适应电液比例控制器

利用Popov超稳定性理论设计的电液比例自适应控制器对电磁铁线圈参数变化、电源扰动等实现自适应控制.该控制器采用MCS-51单片机实现,结构简单,成本低廉.应用结果表明,它优于常规数字PI、PID控制器.     

桥式起重机采用数字式逆变器提高安全性

1.前言 最近,桥式起重机正向操作与操纵多样化方向发展,随之对搬运效率、维修方便性、安全性、可靠性也提出了严格的要求。为了满足这些要求,开发出一种全面采用数字式逆变器控制的高性能起重机。其具体事例介绍如下。     

数字PID控制器在单相逆变器中的研究

结合面向电机控制领域的嵌入式DSP F2812芯片,将数字PID控制技术应用到逆变器系统中,发挥F2812强大的运算能力和实时多任务处理的能力,能很好地适用于系统高精度的控制要求.     

PWM型有源箝位谐振直流环节逆变器

通过深入分析双幅控制的工作原理,提出了一种适合于有源箝位谐振直流环节逆变器的PWM控制方案.同时采用TMS320F2812型DSP控制器对该方案进行了验证,给出了DSP控制的软件设计流程图.实验结果表明,该PWM控制方案不仅有效地提高了有源箝位谐振直流环节逆变器件的控制精度,而且输出波形稳态精度高,畸变小.     

智能马达控制器(SMC)的应用

SMC智能马达控制器是一种新型三相异步电动机的起动运行控制器.本文介绍了SMC的主要功能和使用方法;通过大量实验波形和数据,对起动和节能运行状态进行了分析研究.     

变频器群控的计算机通讯技术

介绍了西门子MicroMaster变频器的RS－485通信协议,利用TurBoC实现DOS下单台微机与多台变频器的串行通信控制,并能实时检测各变频器的运行状态。     

弱电网下并联逆变器谐振模态分析与抑制方法

建立在弱电网下的多逆变器并联系统的数学模型,利用模态分析法分析了不同参数逆变器并联系统的谐振特性,在此基础上提出了一种通过并联虚拟导纳重塑逆变器输出导纳,同时在电压前馈通道引入自校正滤波器的复合控制策略。 通过仿真实验表明,该方法可以有效降低多逆变器并联系统的谐振失稳风险,同时可以显著提高逆变器对弱电网的适应能力,增强系统稳定性。     

变频器信号采集、分析及故障监测系统

介绍一种对变频器的关键电量进行监测和记录的系统的设计，本系统已经在某钢厂的轧钢生产线上应用，帮助在线监控主轧辊的变频器运行状况、分析信号，如分析谐波等。     

DSP在级联多电平中压变频器中的应用

介绍了级联多电平中压变频器工作原理，给出了总体设计。阐述了硬件体系结构，又用软件工程方法进行数据字典编写、软件模块划分与调度、数据变量定义，降低了难度，提高了系统可维护性，最后开发出产品。经过实验测试，达到要求。     

一种相位相关的闭环频域辨识方法及其在最优PI控制器整定中的应用

最优PI控制器整定需要传递函数模型,且强调模型-90°在相位处的准确性。满足这种要求的模型化方法是应用PI控制器最优整定的关键步骤。为此,本文提出了一种基于双通道继电测试TRFT的相位相关闭环频域辨识策略。在该方法中,首先通过TRFT以闭环方式提取在指定相位的多点频率特性;其次,采用所提出的RNLS频域辨识算法估计过程对象的带有时滞的传递函数模型。最后的仿真取得了令人满意的结果,验证了所提出方法的有效性。本文所提出的建模方法与最优整定相结合构成了一个完整的工业应用框架。     

A closed-loop cross-correlation method for detecting model mismatch in MIMO model-based controllers

Correlation between a dithering signal and the prediction error has been used for detecting model mismatch in univariate model based control systems. This paper extends that approach to MIMO control systems. A closed-loop cross-correlation method is presented to detect which specific input-output pairings of a model-based controller are mismatched. This method may be used in screening the complete set of models and in selecting candidate models for re-identification. The method first finds the rows and columns of the transfer function matrix that contain mismatch, and then the candidates are found by the intersection of the said rows and columns. Placing the system under partial control, whereby one or more of the manipulated variables are held constant, can be used to further reduce the set of candidate models.     

Robust MPC-based current controller against grid impedance variations for single-phase grid-connected inverters

Recently, LCL filters have been widely used in the output of single phase inverters. Since, the grid side inductor in these filters is in series with the grid impedance at the Point of Common Coupling (PCC), it may create new resonances. This phenomena may take the control loop toward instability. In this case, in order to have a reliable operation, the current controller should be insensitive to the grid impedance variation. In order to damp these resonances, researchers have presented some methods using active or passive damping. These methods added an extra loop to the control loop, an extra passive component in the filter or extra sensor in the control process. But in most of them, the complexity and the cost of controller have been increased. Therefore, presenting a simple control method without extra sensor, passive component or extra arrangement can be a promising approach. This paper presents an MPC-based current controller, which is simple and robust against the grid impedance variation and even the variation of the LCL filter parameters. In contrast to classical multi-loop controller like Proportional-Resonant (PR) controllers, the proposed control method does not need any parameter tuning. In the proposed controller, the switching plan and duty cycles are determined by a cost function and a switching table. Therefore, at the same time with any variation in grid impedance, the proposed controller changes the next switching state and duty cycle. Operating performance like look-up table, searching in all possible switching states to find the best state for the next switching period, makes the controller adaptive and robust against the variation of LCL filter parameters. In order to confirm the effectiveness of the proposed controller, simulations and experimental results of the proposed controller are compared with a classical PR controller.     

A systematic approach for the sequence controller design in manufacturing systems

This paper presents a systematic approach for the design and implementation of the sequence controller in manufacturing systems. By employing the IDEF0, we construct the simplified Petri net controller (SPNC) through the material flow diagram and the information flow diagram. Then, the ladder logic diagram (LLD) can be transformed from the SPNC through the token passing logic (TPL). The proposed approach, including the IDEF0, SPNC, and TPL tools, leads to the standard IEC1131-3 LLD for PLC implementation. Finally, an application of a stamping process is provided to illustrate the design procedure of the developed approach .     

Performance assessment of static lead-lag feedforward controllers for disturbance rejection in PID control loops

This paper assesses the performance of feedforward controllers for disturbance rejection in univariate feedback plus feedforward control loops. The structures of feedback and feedforward controllers are confined to proportional-integral-derivative and static-lead-lag forms, respectively, and the effects of feedback controllers are not considered. The integral squared error (ISE) and total squared variation (TSV) are used as performance metrics. A performance index is formulated by comparing the current ISE and TSV metrics to their own lower bounds as performance benchmarks. A controller performance assessment (CPA) method is proposed to calculate the performance index from measurements. The proposed CPA method resolves two critical limitations in the existing CPA methods, in order to be consistent with industrial scenarios. Numerical and experimental examples illustrate the effectiveness of the obtained results.