All digital folded low‐area,low‐power maximum power point tracking chip for photovoltaic energy conversion system

In this paper, we propose and implement a 12‐bit area‐efficient folded all‐digital maximum power point tracking (MPPT) chip based on gain‐adaptive perturb‐and‐observe algorithm for photovoltaic energy conversion system. Alternative to DSP or micro controller, realizing the MPPT algorithm by using ASIC can achieve higher energy conversion efficiency, lower power consumption and smaller chip area. By using gain‐adaptive perturb‐and‐observe MPPT algorithm, overall system power consumption can be reduced by overcoming the periodic perturbation issues that occur in conventional perturb‐and‐observe MPPT algorithm. The utilization of proportional integral controller allows fast and stable tracking of the maximum power point. Under high intensity sun illumination, the gain‐adaptive perturb‐and‐observe algorithm performs three times faster than the conventional perturb‐and‐observe MPPT algorithm. Under low intensity sun illumination, the gain‐adaptive perturb‐and‐observe algorithm can provide the same power conversion efficiency as the conventional perturb‐and‐observe MPPT algorithm. By using folding VLSI architecture, the MPPT algorithm can be realized with 74% chip area saving and 77% power consumption reduction. Finally, our proposed MPPT chip is implemented in TSMC0.18‐µm process, with 0.85 mm*0.79 mm chip area and 97.9% power conversion efficiency. Copyright © 2013 John Wiley & Sons, Ltd.     

Effective MPPT technique and robust power control of the PMSG wind turbine

Wind generator performance improvement requires sophisticated and robust control techniques to overcome various constraints and achieve optimal aerodynamic energy conversion. Because of the continuously changing nature of the wind, the output power of a wind energy conversion system (WECS) can be maximized if the wind rotor is driven at an optimal rotational speed for a particular wind speed. This is achieved with a maximum power point tracking (MPPT) controller. Over the years, a variety of MPPT studies have been made, but very few provide guidelines to single out the most suited MPPT technique. In this paper, a comprehensive comparison of the four most used schemes has been made in relation to a permanent magnet synchronous generator (PMSG) wind turbine system. These techniques can be classified into various categories. The obtained results show clearly the superiority of the fuzzy logic control (FLC) technique. Using this MPPT approach, the generated power by the turbine is considered to be, in terms of power control, an auxiliary source feeding a grid. To achieve smooth regulation of the active and reactive power exchange between the PMSG and the grid, direct power control, using space vector modulation DPC‐SVM strategy combined with sliding mode control (SMC) is applied in the grid‐side converter. Simulation results show the efficiency and reliability of the control strategy proposed in this paper. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Maximum‐power operation of a stand‐alone PV system using fuzzy logic control

The PV array has a unique operating point that can supply maximum power to the load. This point is called the maximum‐power point (MPP), and is located on the output characteristics of the array. The locus of this point varies, non‐linearly, with the unpredictable variations in the solar insolation and/or the cell temperature. Thus, to operate the PV array at its MPPs for every instant, the PV system must contain a maximum‐power point tracking (MPPT) controller. This article proposes the application of the fuzzy logic controller (FLC) to operate a suggested PV control system at the MPP of the array for every instant. The simulation of the system indicates that the use of the FLC gives good results for the MPPT. Copyright © 2002 John Wiley & Sons, Ltd.     

Novel straight and circular road driving control of electric power assisted wheelchair based on fuzzy algorithm

This paper describes a novel straight and circular road driving control scheme for electric power‐assisted wheelchairs. “Electric power‐assisted wheelchair” which assists the driving force by electric motors is expected to be widely used as a mobility support system for elderly people and disabled people, however, the performance of straight and circular road driving must be further improved because the two wheels drive independently. This paper proposes a novel driving control scheme based on fuzzy algorithm to realize stable and reliable driving on straight and circular roads. The suitable assisted torque of the right and left wheels is determined by fuzzy algorithm based on the posture angular velocity of the wheelchair and the human input torque proportion of the right and left wheels. Some experiments on the practical roads show the effectiveness of the proposed control system. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(1): 36–44, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20846     

A current sensorless MPPT control method for a stand‐alone‐type PV generation system

In this paper, a current sensorless MPPT control method for a stand‐alone‐type PV generation system is proposed. This control method offers advantages of the simplified hardware configuration and low cost by using only one sensor to measure the PV output voltage. When used as a stand‐alone‐type with a battery load, the experimental results show that the estimated values of PV output current are accurate, and the use of the proposed MPPT control increases the PV generated energy by 16.3% compared to the conventional system. Furthermore, the authors clarified that the proposed method has an extremely high UUF (useful utilization factor) of 98.7%. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(2): 65– 71, 2006; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20424     

A study of a two‐stage maximum power point tracking control of a photovoltaic system under partially shaded insolation conditions

A photovoltaic (PV) array shows relatively low output power density, and has a greatly drooping current–voltage (I–V) characteristic. Therefore, Maximum Power Point Tracking (MPPT) control is used to maximize the output power of the PV array. Many papers have been reported in relation to MPPT. However, the current–power (I–P) curve sometimes shows multi‐local maximum power points mode under nonuniform insolation conditions. The operating point of the PV system tends to converge to a local maximum output power point which is not the real maximal output point on the I–P curve. Some papers have tried to avoid this difficulty. However, most of those control systems become rather complicated. The two‐stage MPPT control method is proposed in this paper to realize a relatively simple control system which can track the real maximum power point even under nonuniform insolation conditions. The feasibility of this control concept is confirmed for steady insolation as well as for rapidly changing insolation by simulation study using software PSIM and LabVIEW. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(4): 39–49, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20188     

A linearly adaptive gate drive technique for light‐load efficiency improvement of DC–DC converters

This paper presents a linearly adaptive gate drive technique to improve the light‐load efficiency of DC–DC converters. The optimal‐driving voltages of the power MOSFETs for reducing gate‐driving loss can be well modeled by a linear function of the load current. By scaling the gate drive voltage dynamically with respect to load current, the light‐load efficiency can be enhanced. The experimental result shows that the proposed gate drive technique can attain about 9% incremental light‐load efficiency enhancement. Copyright © 2008 John Wiley & Sons, Ltd.     

Levitation force assist through LSM armature currents in superconducting maglev vehicle

In a superconducting maglev vehicle, levitation forces produced by the interaction between the ground levitation coils and the onboard SCMs become insufficient when the running speed is low. This paper presents a levitation force assist method through the control of LSM armature currents, which usually function to generate propulsion forces. The levitation assist system is constructed in terms of d‐axis armature currents, leading to the definition of the vertical force coefficient of propulsion system. The calculated results show the feasibility of the system, which produces damping forces as well as levitation assist forces. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(4): 45–52, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20260     

光伏发电系统最大功率跟踪控制的研究

随着电力电子技术的进步,将光伏电池发出的直流电经过逆变并入电网的技术逐渐成熟。因为光伏电池的转化效能有限,所以,对光伏电池的最大功率点跟踪(MPPT)已成为研究的热点之一。以太阳能发电体系为主,对光伏电池的伏安特性、P-U特性详尽分析,并设计了MATLAB仿真,继而引出光伏发电系统的最大功率跟踪。选用扰动观察法进行MPPT控制,并设计了相应的MATLAB仿真。验证了设计的可行性。     

Maximum power point tracking with estimation of the capacitance of the capacitor connected to photovoltaic array

This paper presents a new perturbation and observation method with a capacitance estimation technique for maximum power point tracking (MPPT) in a photovoltaic system. Usually, the maximum power point is tracked by increasing or decreasing the duty ratio of power switching devices. However, it is well known that actual capacitance of an electrolytic capacitor in parallel with a photovoltaic array has 50% tolerance of its nominal value and also that its capacitance value degrades as time passes. If the variation of the duty ratio is determined and fixed using the capacitor nominal value, the MPPT performance may be degraded. Therefore, we must use the actual capacitance in order to improve the MPPT performance. In our system, we applied the model reference adaptive system (MRAS), then obtained the accurate capacitance value and accordingly corrected the duty ratio variation. As a result, it was possible to obtain high MPPT performance. Experimental results show that the proposed method can stably track the maximum power point at widely changing capacitance values by using a newly developed buck‐boost chopper‐type power inverter. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(4): 75–85, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10150     

基于双向变换技术的光伏LED照明系统设计

研究了基于Zeta/Sepic双向变换器的光伏半导体发光二极管(LED)照明系统,提出一种充电控制算法,其既能实现太阳能电池的最大功率点跟踪(MPPT)又能满足蓄电池电压限制条件和浮充特性;设计一种基于HV9930控制芯片的LED恒流驱动电路。构建实验系统,测试表明,控制器可以根据蓄电池状态准确地在MPPT、恒压、浮充算法之间切换,MPPT充电效率较恒压充电显著提升,LED驱动电路恒流效果好。     

独立式LED太阳能光伏照明系统的设计

设计了一种独立式LED太阳能光伏照明系统。利用改进的增量电导法对太阳能电池输出进行最大功率点跟踪(Maximum Power Point Tracking,简称MPPT)控制,根据独立式太阳能LED照明系统的工作特性,采用一种新型的MPPT充电控制策略。设计了大功率白光LED灯具恒流驱动电路及自动调光功能,用于维持室内照度的稳定。     

光伏系统最大功率点跟踪算法的改进及应用

在光伏发电系统中需对光伏电池的最大功率点进行跟踪来提高系统的输出功率.这里以光伏电池输出非线性特性为切入点展开研究,分析常规电导增量法和自适应算法的优缺点,针对其最大功率点跟踪(MPPT)动态和稳态性能不佳及启动过程特性较差的问题,提出改进的MPPT算法.在Madab/Simulink下进行了建模和仿真,仿真结果表明该...     

小型风光互补MPPT控制的研究

为提高小型风光互补发电系统的效率,增强系统的稳定性,使发电系统的性能得到优化,将最大功率点跟踪(MPPT)控制策略应用到小型风光互补发电系统中,此控制策略可以跟踪蓄电池的最大充电功率,最大程度地利用风能和太阳能,并对蓄电池充电控制方案分段优化,对蓄电池快速合理充电,实现小型风光互补发电系统的智能化控制.     

Evaluation and discussion of disturbance observer‐based anti‐slip/skip readhesion control for electric train

The improvement of adhesion characteristics is very important for electric trains. The drive system of electric trains must have fine anti‐slip and anti‐skid readhesion controls. In order to achieve the required adhesion, we have already proposed an anti‐slip/skid readhesion control system based on disturbance observer and sensorless vector control. Moreover, we have already applied the proposed method to actual electric multiple unit trains Series 205‐5000. In this paper, using the experimental results of Series 205‐5000 and the numerical simulation results, we evaluate the proposed anti‐slip/skid readhesion control system and confirm that the system has the desired driving wheel torque response. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 55–64, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20834     

单级式光伏并网逆变系统中的最大功率点跟踪算法稳定性研究

单级式光伏并网逆变系统具有拓扑简单，成本较低的优点。但是这种系统中只存在一个能量变换环节，太阳能最大功率点跟踪(Maximum power point tracking, MPPT)、电网电压同步和输出电流正弦度等控制目标要求同时得到考虑，实现较为复杂。该文提出了一种改进的MPPT算法，在实现上述功能的同时，显著提高了单级式光伏并网逆变系统在光照强度快速变化时的稳定性。该算法的改进主要在于稳态情况下，调整光伏阵列工作点时根据增减方向分别选取合适的步长值；动态情况下，采用前馈方法检测光照强度突变过程，从而迅速改变并网系统运行状态以避免母线电压崩溃现象。基于PSIM仿真平台，对比了定步长MPPT算法和新算法，在阐述算法改进的基础上给出了仿真结果。实验室还建立了300Wp的单级式光伏并网逆变系统，应用全数字化DSP控制技术和改进MPPT算法，实现了系统的并网和可靠运行。仿真和实验结果表明，应用改进MPPT算法的单级式光伏并网逆变系统能够准确跟踪太阳能电池最大功率点，并具有较好的稳定性。     

Minimum energy path search for a manipulator in consideration of all nonlinear characteristics by GA and its experiments

The dissipated energy even of a manipulator must be decreased in order to improve the environment of the earth. This paper describes an optimal path which minimizes the dissipated energy in PTP motions of a vertically articulated manipulator. The dynamic equation of the manipulator is nonlinear due to centrifugal, Coriolis, gravity, and Coulomb friction forces. Moreover the driving system of the joints is also nonlinear in that the generating torque is expressed by a third‐degree polynomial with respect to current. Therefore, an optimal path cannot be obtained by solving a two‐point boundary‐value problem analytically. In this paper an optimal path is searched for by a Genetic Algorithm (GA) in cases in which all kinds of nonlinear characteristics of the manipulator, including the driving system, are taken into consideration. The obtained optimal velocity functions are applied to a vertically articulated manipulator with two direct‐drive motors. The dissipated energy is measured by integrating the input power to the motors. Experimental results agree with the simulation values only when all kinds of nonlinearity are taken into consideration. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(3): 26–34, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20437 Copyright © 2006 Wiley Periodicals, Inc.     

基于最大推力电流法的凸极式永磁直线同步电动机无速度传感器推力直接控制

针对凸极式直线永磁同步电动机的推力生成机制,本文提出了一种高性能的直线永磁同步电动机伺服驱动--基于最大推力电流法的无速度传感器直接推力控制.这一控制方式充分利用了磁路结构不对称所生成的磁阻推力,并将其与结构简单、响应快速的直接推力控制结合,使得电动机效率得以提高,功耗降低,响应速度更快.仿真实验结果证实了该方法的有效性.     

基于模糊控制的MPPT在光伏并网发电系统中的应用

为了提高光伏并网发电系统的输出效率,减小系统正常工作时的电压波动,提出了一种基于模糊控制的最大功率点跟踪方法.在分析了光伏电池的特性和几种光伏并网发电系统的最大功率点跟踪算法后,针对扰动观测法的不足,将模糊控制应用到最大功率点跟踪控制算法中,提出基于扰动观测法的模糊控制策略.在Matlab/Simulink中进行了系统...     

独立光伏LED照明系统研究与设计

针对传统照明控制装置充放电路分开设置存在结构复杂、可靠性差、效率低等问题,研究了基于Zeta/Sepic双向变换器的光伏LED照明系统;提出了一种充电算法,其既能实现光伏电池最大功率点跟踪(MPPT)又能满足蓄电池电压限制条件;设计了一种基于HV9930控制芯片的LED恒流驱动电路。实验结果表明:控制器可以根据蓄电池状态准确地在MPPT、恒压和浮充算法之间切换,MPPT充电效率较恒压充电提升显著,LED驱动电路恒流效果好。