Improved Torque and Flux Performance of Type-2 Fuzzy-based Direct Torque Control Induction Motor Using Space Vector Pulse-width Modulation

The conventional proportional integral controlled direct torque control of an induction motor using the space vector pulse-width modulation technique may provide satisfactory dynamic response. However, the proportional integral controller (PIC) does not provide efficient dynamic performance in the induction motor drive during sudden changes in the load or speed. To improve dynamic performance of the induction motor drive, the PICs are replaced by type-2 fuzzy logic control. The type-2 fuzzy improves the starting transient performance as well as the steady-state response. In addition, the type-2 fuzzy direct torque control provides lesser current total harmonic distortion, flux distortion, and torque pulsation of the induction motor drive compared to conventional direct torque control. A MATLAB Simulink (The MathWorks, Natick, Massachusetts, USA) model for direct torque control with type-2 fuzzy logic control is developed to simulate the response of an induction motor drive with different operating conditions. The space vector pulse-width modulation technique is used to drive the inverter, as it produces lesser total harmonic distortion in inverter current and voltage waveforms for a given switching transition due to the single switching frequency for the movement of each state vector. A prototype type-2 fuzzy-based direct torque control induction motor with space vector pulse-width modulation is developed to validate the simulated response. The control signals for the inverter are generated by the DSPACE DS1104 (DSPACE GmbH, Germany) to drive a two-HP induction machine.     

Prediction-based Deadbeat Control for Grid-connected Inverter with L-filter and LCL-filter

Abstract—In this article, an improved deadbeat control algorithm suitable for digital signal processor-based circuit implementation is proposed. The control algorithm allows the derivation of a nearly sine wave output current with a fixed switching frequency of a current-controlled voltage source inverter. Two low-pass output filters configurations are considered in this study: a simple inductance filter and an LCL-filter. By taking advantage of prior knowledge of the state variables’ shape, the improved deadbeat control algorithm is based on a simple prediction model to derive the expected duty cycle needed to switch on and off the power switches. The control study of the grid-connected inverter with L and LCL output filters has been considered using a co-simulation approach with (Powersim Inc., Rockville, Maryland, USA) and MATLAB software (The MathWorks, Natick, Massachusetts, USA). The obtained results show the improvement of both shape quality and tracking accuracy of the output current quantified by low ripple content and a nearly unity power factor.     

单相正弦波变换器的设计与仿真

针对一些电动机对供电品质要求较高的问题,提出了一种新的正弦波变换器实现方法。通过分析单极性倍频调制PWM原理,用高速TMS320F2812DSP作处理芯片,驱动电路采用IGBT智能模块M57959L,结果使得正弦变换器体积减小、可靠性增强。设有合理的过电压保护和LC带阻滤波以及RLC低通滤波双重滤波,保证工频升压变压器输出高质量的正弦电压交流电。最后进行DC-AC仿真实验,并对样机进行正弦波形测量,验证了方案的正确性。     

大型循环流化床锅炉一次风机节能改造可行性分析

针对目前国投盘江电厂风机运行中效率较低导致厂用电较高的情况,从风机、电机系统出发,分别研究各个环节中对风机系统效率影响的因素及参数,给出风机及管路改造方案、调速方案,形成国投盘江电厂风机节能的完整技术体系,最终使电厂风机系统中风机效率、装置及系统效率达到最优值。     

造纸机械变频多传动控制系统的基本原理及应用

详细介绍了速度同步、主从控制和负荷分配时造纸机械变频多传动控制系统的基本控制原理和应用方式。     

一种基于PLC和变频器的电机控制系统设计研究

随着变频调速技术和可编程控制器的飞速发展,它们已经成为当代工业自动化的主要装置之一,在工业生产领域得到广泛使用。设计一种基于可编程逻辑控制器和变频器的电机控制系统,对电动机进行变频调速,实验结果表明,闭环系统精度较好,在对精度有较高要求情况下应采用闭环控制。     

Recent Advances in Methods and Techniques for Freshness Quality Determination and Evaluation of Fish and Fish Fillets: A Review

The freshness quality of fish plays an important role in human health and the acceptance of consumers as well as in international fishery trade. Recently, with food safety becoming a critical issue of great concern in the world, determination and evaluation of fish freshness is much more significant in research and development. This review renovates and concentrates recent advances of evaluating methods for fish freshness as affected by preharvest and postharvest factors and highlights the determination methods for fish freshness including sensory evaluation, microbial inspection, chemical measurements of moisture content, volatile compounds, protein changes, lipid oxidation, and adenosine triphosphate (ATP) decomposition (K value), physical measurements, and foreign material contamination detection. Moreover, the advantages and disadvantages of these methods and techniques are compared and discussed and some viewpoints about the current work and future trends are also presented.     

基于等效电路的三相电压型桥式逆变电路分析方法研究

三相电压型桥式逆变电路是很多应用领域的核心电路,但其工作原理复杂、难理解。简述了传统的三相电压型桥式逆变电路的分析方法,指出了传统分析方法的不足,提出了依据IGBT的控制时序确定6个IGBT的通断,从而得到三相电压型桥式逆变电路的等效电路,并基于等效电路分析三相电压型桥式逆变电路工作原理的方法。分析过程简单易懂,分析结果直观明确,克服了传统分析方法复杂、繁琐和理解困难等不足。     

红曲霉固态发酵生产Monacolin K工艺条件的研究

通过对红曲霉TQ-57固态发酵生产Monacolin K的工艺条件的研究,确定了固态发酵的工艺条件为：培养基水分50%,相对湿度75%,起始pH值为6.0,发酵温度25℃,发酵时间16d,蛋白胨用量为3.0%,甘油用量为0.2%,Monacolin K量可达到2.243mg/g。通风培养时Monacolin K量为2.563mg/g干基质。     

便携式地铁列车辅助逆变器故障诊断系统设计

设计了一种便携式辅助逆变器故障智能诊断系统,对系统的工作原理、硬件结构及软件技术进行了详细描述。运用神经网络方法,分析故障产生的原因并确定故障发生的位置,以便及时维修。该诊断系统除具有“便携式”的特征外,还具有操作简便、诊断与分析自动化、智能化等特点,并且能够存储记录数据,方便以后分析查看,适用于车间检修和运营中突发故障现场对辅助逆变器故障进行快速、自动诊断。