基于MATLAB的光伏离网系统仿真研究

介绍了单相光伏离网发电控制仿真系统,采用DC/DC和DC/AC两级拓扑结构对光伏离网系统进行了研究和设计。研究光伏组件、输入滤波电容和离网逆变器之间的耦合关系,通过双闭环控制策略,实现直流母线电压稳定以及逆变器稳定输出。在MATLAB仿真环境下,对所设计的光伏离网系统进行了仿真,仿真结果表明该方案和控制策略的正确性。     

微网的光伏系统并网运行和离网运行的控制策略

光伏微网逆变器分为并网运行和离网运行双模式。本文详细分析和研究微网逆变器的控制策略,确定了在离网工作模式下的电压闭环控制策略和在并网工作模式下的瞬时电流控制策略。根据选定的控制策略分别对其控制系统进行了建模仿真和相关参数的设计,并利用Matlab/Simulink软件对并网和离网模式以及两种模式之间的相互切换进行仿真,仿真结果证明了本文所采用的控制方法的正确性和有效性。     

两级拓扑结构的离网型光伏逆变器设计

光伏发电系统由太阳能电池阵列、蓄电池、控制器、逆变器等部件组成。本文针对光伏发电系统中的核心设备——逆变器,介绍了一种离网型逆变器的设计方法。主电路采用两级变换拓扑结构,控制电路选用单片机C8051F330和SG3525作为控制芯片,设计了蓄电池充放电电路、交直流变换电路、电压采集电路和保护电路等单元,并对各单元的控制方式进行了说明,证明了该逆变器适用于离网型光伏发电系统。     

一种低成本的大功率光伏离网逆变器设计

针对光伏离网逆变器功率小且SPWM控制算法实现复杂的问题,研究了SPWM数字化实现方法,提出一种基于STM32F030超值系列单片机的大功率、低成本光伏离网逆变器实现方案。该方案先将光伏蓄电池中的直流电逆变为工频低压交流电,再用工频变压器升压到市电。其中,为控制电路供电的DC/DC电源实现了宽电压输入范围跳周期调制,降低开关损耗;逆变桥臂用7个MOSFET代替1个IGBT,降低成本,增大输出功率,最大输出功率达6 720 W。控制算法上提出改进的SPWM数字化实现方法,该方法易于在低成本微控制器上实现,进一步降低控制成本。通过实验证明,该逆变器带负载时稳定输出220 V工频正弦交流电。     

LCL型并网逆变器电流控制稳定性分析

在LCL型光伏并网逆变器中,电流控制器的比例控制系数设计不合理易造成系统不稳定,甚至损坏逆变器。对采用逆变侧电感电流反馈的LCL型三相光伏并网逆变器进行数学建模,运用Routh-Hurwitz稳定性判据基于系统离散化模型进行稳定性分析,可求得比例控制系数的精确范围。分析逆变侧电感、滤波电容以及网侧电感的取值与比例控制系数的关系,探讨滤波电感和电容的取值对系统稳定性的影响。通过Matlab仿真及在50 k W光伏逆变器实验平台上进行测试,验证了所进行的稳定性分析的正确性。     

基于推挽电路的光伏并网发电微型逆变器研究

随着新能源的逐步推广,光伏并网发电系统得到了发展。其系统通常由多块光伏电池板串联依此提高整个光伏支路电压,通过DC／DC变换器或DC／AC逆变器连接负载或电网。针对以往方式,本文研究了一种由前级推挽正激电路的变换器及后级Dc／Ac逆变器两级联接式的光伏并网发电微型逆变系统。其前级通过光伏电池板最大功率点跟踪进行高频准单极性控制,后级采用流内环,电压外环双闭环控制。仿真研究表明,该系统具有并网电流质量高,动态特性好,最大功率点跟踪精确、效率高、稳定性高等优点。     

光伏组网单元直流侧蓄电池储能系统研究

采用了双向半桥Dc/Dc对光伏组网单元直流侧蓄电池进行充放电控制;简单说明了VSI逆变器的结构和原理:分析了双向DC/DC变换器电感电容的选取方法。通过搭建以蓄电池储能为核心的仿真模块,采用功率外环电流内环、电压外环电流内环这两种控制方式,分别在光照强度变化不大以及光照有大幅度跌落这两种情况下进行了仿真分析。仿真结果验证了这两种控制方法在稳定逆变器输出以及直流母线电压的有效性,也体现了功率外环电流内环控制的优越。     

富昌能源事业部亮相PV China2011展示多款太阳能解决方案

近日,富昌能源事业部在为期三天的2011年中国光伏发电与系统集成技术研讨会暨展示会上展示了多款光伏微型逆变器、最大功率追踪优化器、离网并网逆变器、电流/电压检测系统等     

基于PSpice的光伏并网系统仿真研究

采用DC／DC和DC／AC两级拓扑结构对光伏并网系统进行了研究和设计,采用改进的定电压跟踪法（CVT）实现最大功率点闭环跟踪,并将PWM控制器引入并网逆变中,采用三角波比较方式实现SPWM电压逆变和输出电流的波形跟踪与控制,在电压、电流内环的基础上引入功率外环以实现系统前后级功率平衡和能量管理,采用基于PSpice的光伏电池仿真模型对所设计光伏并网系统进行了仿真。仿真结果表明,基于PSpice的光伏仿真模型能够有效地模拟实际光伏并网系统的行为特征,将PSpice软件用于光伏发电系统的仿真是可行的。     

离网光伏逆变器SPWM调制方法研究

全桥逆变电路广泛应用于光伏逆变器中,按照逆变桥上下结构和前后臂结构,以及同臂管是否有互补,本文详细对比分析了全桥逆变电路中正弦脉宽调制(SPWM)驱动的几种调制方法,并进行仿真与分析。选择在离网光伏逆变器中最合适的一种纯正弦波调制方法,设计了相应的样机硬件电路,进行了实验验证。     

太阳能电池发电量实时监控系统

为了实时监控太阳能电池发电量,设计一种太阳能电池发电量实时监控系统,该系统利用单片机和霍尔电流传感器实时测量太阳能电池的输出电压、电流得到输出功率,然后经运算得到电量值送液晶显示器显示结果。实验表明：该系统测量误差小于3％．且低成本、低功耗,使其在离网光伏系统中应用广泛。     

Development of an FPGA-based system for real-time simulation of photovoltaic modules

Photovoltaic (PV) simulators are indispensable for the operational evaluation of PV energy production system components (e.g. battery chargers, DC/AC inverters, etc.), in order to avoid the time-consuming and expensive field-testing process. In this paper, the development of a novel real-time PV simulator based on Field Programmable Gate Arrays (FPGAs), is presented. The proposed system consists of a Buck-type DC/DC power converter, which is controlled by an FPGA-based unit using the Pulse Width Modulation (PWM) principle. The system operator is able to define both the PV module type to be simulated and the environmental conditions under which the selected PV module operates. The proposed design method enhances the rapid system prototyping capability and enables the reduction of the power converter size and cost due to the high clock speed feature of the FPGA-based control unit. The experimental results indicate that, using the proposed method, the PV module current-voltage characteristics examined are reproduced with an average accuracy of 1.03%.     

Development of a microcontroller-based, photovoltaic maximum powerpoint tracking control system

Maximum power point tracking (MPPT) is used in photovoltaic (PV) systems to maximize the photovoltaic array output power, irrespective of the temperature and irradiation conditions and of the load electrical characteristics. A new MPPT system has been developed, consisting of a buck-type DC/DC converter, which is controlled by a microcontroller-based unit. The main difference between the method used in the proposed MPPT system and other techniques used in the past is that the PV array output power is used to directly control the DC/DC converter, thus reducing the complexity of the system. The resulting system has high-efficiency, lower-cost and can be easily modified to handle more energy sources (e.g., wind-generators). The experimental results show that the use of the proposed MPPT control increases the PV output power by as much as 15% compared to the case where the DC/DC converter duty cycle is set such that the PV array produces the maximum power at 1 kW/m² and 25°C     

Design and performance analysis of generalised integrator-based controller for grid connected PV system

This article discusses the design and control of a single-phase grid-connected photovoltaic (PV) system. A 5-kW PV system is designed and integrated at the DC link of an H-bridge voltage source converter (VSC). The control of the VSC and switching logic is modelled using a generalised integrator (GI). The use of GI or its variants such as second-order GI have recently evolved for synchronisation and are being used as phase locked loop (PLL) circuits for grid integration. Design of PLL circuits and the use of transformations such as Park’s and Clarke’s are much easier in three-phase systems. But obtaining in-phase and quadrature components becomes an important and challenging issue in single-phase systems. This article addresses this issue and discusses an altogether different application of GI for the design of compensator based on the extraction of in-phase and quadrature components. GI is frequently used as a PLL; however, in this article, it is not used for synchronisation purposes. A new controller has been designed for a single-phase grid-connected PV system working as a single-phase active compensator. Extensive simulation results are shown for the working of integrated PV system under different atmospheric and operating conditions during daytime as well as night conditions. Experimental results showing the proposed control approach are presented and discussed for the hardware set-up developed in the laboratory.     

馈能型直流电子负载数字化控制的研究

馈能型直流电子负载作为一种新型电力电子装置,较传统的负载相比,具有节能、体积小、重量轻等特点。本文简要介绍了基于DSP芯片TMS320F2812控制的馈能型直流电子负载系统的结构、原理,重点对基于有源钳位技术的直流变换部分,采用电流滞环控制的逆变部分,以及同步锁相环节的数字化控制进行了研究,并进行了仿真验证。     

新能源不间断供电系统的优化设计与应用研究

针对无电地区设备不间断供电难的问题,提出采用新能源离网型不间断供电的思路;对风光互补供电系统的设计方法、容量配置的计算方法和设备的选型等做了详细讨论和优化设计,并结合军用风光油互补系统实验样机的实际应用,论证了系统优化设计的合理性和可行性。     

Microcontroller‐based simple maximum power point tracking controller for single‐stage solar stand‐alone water pumping system

A simple microcontroller‐based maximum power point tracking controller is proposed for a single‐stage solar stand‐alone water pumping system for remote, isolated, and nonelectrified population, where less maintenance, low cost, and an efficient system is of prime interest. It consists of a photovoltaic (PV) module, a DC–AC converter utilizing space‐vector pulse‐width modulation, an induction motor coupled with a water pump, a voltage sensor, and a current sensor. A space‐vector pulse‐width modulation‐controlled DC–AC converter aided by a fast‐acting on–off supervisory controller with a modified perturb‐and‐observe algorithm performs both the functions of converting PV output voltage to a variable voltage, variable frequency output, as well as extracting the maximum power. A limited variable step size is preferred during transient state, and a steady frequency, which is calculated on the basis of steady‐state oscillation, is set during steady state. A fast‐acting on–off supervisory controller regulates DC link voltage during steady state and enables maximum power point tracking algorithm only during transient state to draw a new voltage reference. In the event of low voltage, the controller switches off the motor but continuously scans for an available PV voltage. The system is not protected against an overcurrent because the maximum current is equal to its short circuit current. The 16‐bit microcontroller dsPIC6010A (Microchip Technology, Inc., Chandler, AZ, USA) is used to implement the control functions. The proposed controller is verified through simulation as well as tested in the laboratory prototype model. The simulation and experimental results show good correlation. Copyright © 2011 John Wiley & Sons, Ltd.     

三相星型六状态无刷直流电动机传动系统仿真研究

针对无刷直流电动机,运用三相星型六状态的控制方式,建立无刷直流电动机的数学模型,分析其电子控制的运行状态,最后利用MATLAB/simulink搭建了三相星型六状态无刷直流电动机的仿真模型,并进行仿真。仿真结果表明,系统性能良好,为无刷直流电动机的应用提供依据。     

基于dsPIC33E的电动汽车充电机的研究与设计

本文设计了一种适合于混合动力汽车充电的充电系统,输入为单相交流市电,采用AC/DC和DC/DC相结合的拓扑结构以满足相应的国家标准和充电机的功能需求,利用低成本控制器dsPIC33E进行控制。在对上述主电路拓扑的工作原理进行分析的基础上,给出了部分关键参数的设计方法,并分别设计了前后级电路的控制策略。为了防止在后级DC/DC电路输出模式切换时引起振荡而设计了一种切换方法。最后在理论分析的基础上进行了仿真和实验研究,仿真和实验结果验证了本文所设计的充电机的可行性。