反激式拓扑在回馈式电子负载中的应用

能量回馈型电子负载是一种可模拟阻性负载以及任意功率因数的感性和容性负载,该模拟电路主要由前级的反激式电路完成,反激式电路的主电路拓扑采用反激式结构,把老化电源输出的直流电压升压到400V后,输送给并网逆变器,使吸收能量回馈电网。     

基于DSP2812的全新数字锁相环

鉴于能量回馈控制系统要求回馈电流与电网电压严格同频同相,结合锁相环原理,提出了一种基于DSP TMS320F2812的高精度数字锁相控制方案.利用DSP内部的捕获单元、通用定时器和比较单元,方便地实现了对电网电压和回馈电流的信号捕获,从而达到调频调相的目的,达到并网条件.实验表明,此方法精度高,锁相速度快,保证了并网系...     

台达AFE2000，给力节能低碳

帮助工业企业实现节能低碳,主动式电源回生单元AFE2000就是其中非常优秀的一员。 AFE2000采用高阶控制算法,能真正实现能量双向流动,与变频器搭配使用,可实现变频器调速系统的四象限运行,把电机再生的能量回馈到电网中,取代例如传统的刹车电阻。实际应用测试结果显示,使用AFE2000后,再生能量回馈电网效率高达95％...     

浅析能馈型交流电子负载的设计应用

本文研究了一种带能量回馈功能的交流电子负载,既能精确控制被试电源放电电流又能将被试电源释放的能量无污染地回馈到电网上,实现了能源的再生利用.     

独立、并网双模式户用光伏发电装置的研究与设计

针对户用光伏发电系统的特点和要求进行了系统的研究与设计。系统设计将独立逆变与并网逆变相结合,使系统既可以工作在独立逆变状态,为负载提供正弦交流电源,也可以工作在并网逆变状态,将太阳的能量或蓄电池的能量回馈到电网。本系统采用TI公司32位定点DSP芯片TMS320F2812为控制核心,利用PIC16F877A单片机构成系统的人机操作界面。本文所设计的系统具有完善的保护功能、键盘监控和液晶显示、串口通讯功能,为家庭使用提供了方便。实验结果验证了方案的可行性。     

开关磁阻电机并网逆变模块设计

应用PWM整流器技术设计了一种开关磁阻电机并网逆变模块,在不改变功率变换器主电路的情况下,将开关磁阻电机在发电状态下发出的能量回馈电网。     

变频调速能量回馈控制技术的研究

针对变频调速电动机再生能量回馈应用技术中存在的问题,文章提出了基于DSP控制的双PWM变频调速方案,并进行了理论分析,提供了控制框图,较好地解决了电动机再生能量回馈电网的问题。     

开关磁阻电机并网逆变模块设计

应用PWM整流器技术设计了一种开关磁阻电机并网逆变模块,在不改变功率变换器主电路的情况下,将开关磁阻电机在发电状态下发出的能量回馈电网.     

电梯再生电能的储能回收控制策略研究北大核心CSCD

电池储能是电梯再生能量回收利用的有效方式,针对应用中储能系统容量优化问题,基于回馈电能功率/能量以及变换器电压等约束条件确定电池组边界条件。在此基础上,通过引入制动电阻辅助分流以及电压动态调整的方法,研究了吸收释放再生电能过程的控制策略,并在Matlab/Simulink中搭建仿真模型。仿真结果表明该控制方法可在稳定直流供电网电压的前提下实现再生能量的高效利用,同时有效减少电池系统容量和成本。     

基于DSP控制的能量再生回馈电网研究

利用电力电子技术中的整流、逆变，以及与能量回馈相关的信号反馈控制、数字信号处理（DSP）等控制技术，通过跟踪捕获电网电源信号，将伺服电机在运行过程中快速制动和频繁正反转时所产生的再生能量以SPWM波的形式．转变为与电网电源信号同步的电能信号。同时滤除再生电能SPWM渡中的谐波干扰成分，提高功率因数，将再生能量反馈回电网，予以优化回收。     

并网逆变器控制系统软件设计

随着可再生能源的迅速发展,风力发电并网已成为现代电力电子研究的一个热点。如何实现电能顺利并入电网成为并网技术的一个难点问题。本文首先简要介绍了三相PWM并网逆变器的拓扑结构和并网逆变器控制系统结构图。本文主要对并网逆变器控制系统的软件进行了设计,其中主要包括系统寄存器初始化、A\D采样、坐标变换、锁相等程序。以TMS320F2812为控制核心,研制了一套二电平并网变流器的实验装置,实验结果表明该逆变器具有良好的并网性能,同时也进一步验证了该系统控制策略的正确性与系统软件设计的合理性。     

Coordinating workload balancing and power switching in renewable energy powered data center

There has been growing concern about energy consumption and environmental impact of datacenters. Some pioneers begin to power datacenters with renewable energy to offset carbon footprint. However, it is challenging to integrate intermittent renewable energy into datacenter power system. Grid-tied system is widely deployed in renewable energy powered datacenters. But the drawbacks (e.g. Harmonic disturbance and costliness) of grid tie inverter harass this design. Besides, the mixture of green load and brown load makes powermanagement heavily depend on software measurement and monitoring, which often suffers inaccuracy. We propose DualPower, a novel power provisioning architecture that enables green datacenters to integrate renewable power supply without grid tie inverters. To optimize DualPower operation, we propose a specially designed power management framework to coordinate workload balancing with power supply switching. We evaluate three optimization schemes (LM, PS and JO) under different datacenter operation scenarios on our trace-driven simulation platform. The experimental results show that DualPower can be as efficient as grid-tied system and has good scalability. In contrast to previous works, DualPower integrates renewable power at lower cost and maintains full availability of datacenter servers.     

Passivity-based control design for a grid-connected hybrid generation system integrated with the energy management strategy

Hybrid generation systems produce electric energy from a wide variety of energy sources, including renewable sources. A hybrid system based on renewable sources usually consists of two or more renewable energy sources with the possibility of including storage units so as to enhance the reliability of the system. The hybrid system requires an energy strategy that determines the operation point of each element of the system depending on multiple variables and subjected to the constraints inherent in this kind of systems. In addition, the system needs controllers to command each of these elements in order to reach the operation point established by the energy strategy. Here, we propose a control design via passivity-based control integrated with an energy management strategy for a hybrid generation system based on solar energy and coupled with the grid. The performance of the control methodology is extensively assessed through computer simulation using a comprehensive nonlinear model of the plant. The results show that the controlled system accomplishes the control tasks with good responses, working under very different atmospheric conditions and required load power.     

Decentralized Control for Residential Energy Management of a Smart Users' Microgrid with Renewable Energy Exchange

This paper presents a decentralized control strategy for the scheduling of electrical energy activities of a microgrid composed of smart homes connected to a distributor and exchanging renewable energy produced by individually owned distributed energy resources. The scheduling problem is stated and solved with the aim of reducing the overall energy supply from the grid, by allowing users to exchange the surplus renewable energy and by optimally planning users' controllable loads. We assume that each smart home can both buy/sell energy from/to the grid taking into account time-varying non-linear pricing signals. Simultaneously, smart homes cooperate and may buy/sell locally harvested renewable energy from/to other smart homes. The resulting optimization problem is formulated as a non-convex non-linear programming problem with a coupling of decision variables in the constraints. The proposed solution is based on a novel heuristic iterative decentralized scheme algorithm that suitably extends the Alternating Direction Method of Multipliers to a non-convex and decentralized setting. We discuss the conditions that guarantee the convergence of the presented algorithm. Finally, the application of the proposed technique to a case study under several scenarios shows its effectiveness.      

Current control based power management strategy for distributed power generation system

The integration of renewable energy sources (RES) based distributed generation (DG) systems into electric grid has many challenges such as synchronization, control, power management (PM) and power quality problems. This paper proposes a references current generator (RCG) based PM strategy to control three phase inverter and manage power flow among the DG energy sources, electric grid and load demand under balanced and unbalanced grid conditions. The amplitudes of active and reactive power oscillations are also eliminated and controlled through only one flexible control parameter (FCP) under grid faults and harmonic distortions. Compared with previous similar studies, one of the important contributions is capable to inject maximum active power and minimum reactive power into electric grid and load at inverter power capacity under grid faults Another contribution is to extract the positive and negative sequence (PNS) voltage and current components with the improved fast and robust dual adaptive filters based phase locked loop (DAF-PLL). Fractional order proportional integral (FOPI) is selected as an attractive solution for AC current regulation to exhibit fast transient response and to achieve zero steady-state errors as compared with conventional current regulation controllers in synchronous or stationary frames.     

光伏并网发电系统软件锁相技术的研究

光伏并网发电系统是利用太阳能的主要技术之一,并网逆变器是实现其与电网连接的核心部分。为使光伏并网逆变器逆变输出电流能够更好地跟踪电网电压基波,完成同步锁相功能,本文以1kW单相光伏并网逆变器为研究平台,阐述光伏并网逆变器的工作原理和系统结构,分析并网逆变器的并网控制技术,提出一种基于坐标变换的双park鉴相器的软件锁相技术,最后通过Matlab仿真验证该方法的可行性。     

具有谐波补偿功能的光伏并网逆变器控制策略研究

随着高新能源技术的发展,光伏并网发电在通过逆变器并网时往往会产生大量的不同谐波,并因此消耗大量的电能。接入电网的光伏并网逆变器中存在大量的负载,这将使整体电网质量下降。针对此问题,论文提出一种具有谐波补偿功能的光伏并网逆变器控制方法,通过谐波补偿装置采集电网中的谐波含量,并基于MPPT算法对所采集的谐波进行分析、计算,根据所计算出的分析结果补偿谐波。该技术方案在三相电和单相电情况下均可正常使用。通过在实验室Matlab/Simulink环境下建立系统拓扑构架进行试验,电网中的电流谐波含量大大降低,从而消除了电网谐波对负载光伏并网逆变器的影响,因此,仿真结果验证了理论分析,该技术方案具有一定的实用价值和科研价值。     

Output feedback control of wind energy conversion system involving a doubly fed induction generator

This paper deals with the problem of controlling a wind energy conversion system (WECS) based on the doubly fed induction generator (DFIG), by IGBT‐based back‐to‐back rectifier‐inverter. The goal of control is to maximize wind energy extraction letting the wind turbine rotor operate in a variable‐speed mode. Interestingly, the present study features the achievement of the above energetic goal without resorting to sensors for wind velocity. The control strategy involves: (i) an output feedback non‐linear regulator designed by the backstepping technique and based on the use of a high gain observer; (ii) a sensorless online reference‐speed optimizer designed using the turbine power characteristic to achieve the maximum power point tracking (MPPT) requirement. It is formally shown that the proposed controller actually meets its control objectives. This theoretical result is confirmed by several simulations.     

光伏并网逆变器MLD建模及预测控制算法

光伏并网逆变器传统的开关函数模型在并网过程中的动态响应速度慢,影响了逆变器溃入电网的电能质量。为了解决这一问题,提高光伏并网逆变器的供电质量,分析光伏并网逆变器的混杂特性,通过对逆变器的开关动态引入逻辑变量,建立MLD模型,提出一种基于该模型的预测控制算法。仿真结果表明,基于MLD模型的预测控制算法改善了光伏并网系统的动态性能,达到并网要求条件的时间更短,验证了所提方法的可行。     

Fixed frequency sliding mode control of renewable energy resources in DC micro grid

The rising cost of fossil fuels, their high depleting rate and issues regarding environmental pollution have brought the attention of the researchers towards renewable energy technologies. Different renewable energy resources like wind turbines, fuel cells and solar cells are connected to DC micro grid through controllable power electronic converters. In presence of these diverse generation units, robust controllers are required to ensure good power quality and to regulate grid voltage. This paper presents a sliding mode control based methodology to address the above mentioned challenges. The proposed technique keeps the switching frequency constant so that electromagnetic compatibility (EMC) issues can be solved with conventional filter design. Parallel operation of converter in DC micro gird is considered. Chattering reduction and power quality improvement by harmonic cancellation is proposed. A scaled down hardware for unregulated 11.5 V to 17.5 V input and 24V output is designed and tested. The experimental results show good performance of the controller under different loads and uncertain input voltage conditions. Moreover, the results show the robustness of the closed loop system to sudden variations in load conditions. Furthermore, a significant improvement in power quality is achieved by harmonic cancellation of chattering in the output of the converters.