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将一组几百瓦的光伏电池与电流不连续功率型DC/DC变换器组合成单模块,并将其多块的直流输出端并联后就可得到高功率.再经过一台几千瓦的PWM变频器变为交流电输出,或向电网系统输电或向负载供电,由此构成了光伏功率变换器模块形式的太阳能发电系统.电路经过仿真测试,清楚了它的传输特性,其应用的最大特点是,无论太阳能的发电电压如... 相似文献
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This paper presents a buck-boost PWM power inverter and its application for the residential photovoltaic system. The PWM power inverter is realized by driving an inverter constructed with a high-frequency buck-boost chopper in the discontinuous conduction mode (DCM). The photovoltaic system with the power inverter has the following advantages: (1) the power generated by the photovoltaic array can be transferred to the load and the utility line under any array voltage; (2) isolation between the photovoltaic array and the utility line is performed by a small high-frequency reactor operating as energy storage element; (3) there is no need of a reactor to link the utility line; (4) unity power factor operation is provided; and (5) the system configuration is very simple. the input-output characteristics of the system are analyzed. As a result, the ripple component of the array current and the power flow between the interface and the utility line are derived and verified experimentally. 相似文献
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一种光伏发电系统中辅助电源设计 总被引:3,自引:0,他引:3
针对在光伏发电系统中,光伏电池输出超宽电压的特点,设计了一种以SG6840高集成度"绿色模式"PWM控制器芯片为核心的高频单端反激式开关稳压电源.利用三端稳压器TL431配合SG6840实现了对电源电压的控制和稳压输出,并采用光电耦合器件PC817实现了输入/输出的隔离和反馈.这一款电压输入范围为120~850V,输出电压为24V的单端反激式开关电源,为光伏发电系统中的逆变控制系统等提供了可靠的供电电压.实验测试结果表明,所设计的电源具有优良的稳压性能,而且电压纹波小、负载调整率和电压调整率低.目前该电路已作为辅助电源,成功应用在一台光伏发电系统实验样机中. 相似文献
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光伏发电系统并网电能质量测试数据分析 总被引:1,自引:0,他引:1
太阳能是可再生能源,光伏发电是太阳能发电的主流,近些年来,世界范围内太阳能光伏技术和光伏产业发展很快,江西省的光伏电站也在逐渐增加。厚田沙漠光伏电站是江西省内第一个并网发电的光伏发电系统,结合厚田沙漠光伏电站的并网电能质量测试,详细介绍了开展光伏电站并网电能质量测试的步骤,同时依照测试数据对光伏发电的功率变化、电压偏差、闪变以及谐波含量等方面进行了分析,可为今后光伏电站并网测试提供参考,同时为深入研究光伏并网对电网电能质量的影响提供可靠依据。 相似文献
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针对飞跨电容型三电平光伏逆变器载波移相算法线电压谐波较高,无法灵活控制飞跨电容电压等问题,提出一种基于新型载波同相层叠PWM方法的飞跨电容型光伏发电并网方案。通过增加零电平向量分配环节,平衡飞跨电容电压,降低光伏逆变器线电压谐波。阐述了新型载波同相层叠算法基本原理,分析了该方案降低光伏逆变器线电压THD的优点。通过Matlab/Simulink数字仿真和实验样机,验证了基于新型载波同相层叠方法的飞跨电容型光伏发电并网系统能够有效跟踪最大输出功率,保证直流电压稳定,降低光伏系统输出线电压谐波。 相似文献
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This paper proposes a PWM current source inverter-induction motor drive system with photovoltaic generation. Solar cells are inserted in dc link to obtain constant current characteristics. They are connected to the utility system with a PWM converter. The PWM converter is controlled to obtain the maximum output photovoltaic (PV) power. The PWM inverter supplies sinusoidal currents for an induction motor, which is driven by constant V/f control. A pulsewidth control is utilized in the inverter section because of constant dc link current caused by peculiar V-I solar cell characteristics. In the system proposed here, the PV power is not only used for inverter-induction motor drive but it also flows into the utility system. The experimental results in steady state show that the proposed system has sinusoidal current with unity power factor in the utility system, the maximum output PV power and sinusoidal current/voltage for a motor. The demonstrated results for the separation of the utility system or the motor from the converter-PV-inverter system are given. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (2): 79–87, 1997 相似文献
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三相光伏并网系统的控制策略研究 总被引:3,自引:0,他引:3
本文分析了光伏并网发电系统的工作原理,针对光伏并网发电系统的功率输出级进行了PWM控制策略研究。提出了并网逆变器的直接电流控制策略,并采用电网电压前馈和固定开关频率的控制方案;获得了较快的电流响应速度,实现了并网电流的正弦化和单位功率因数。 相似文献
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Tokuo Ohnishi 《Electrical Engineering in Japan》1991,111(7):104-116
Recently, the voltage-fed type PWM converters have been investigated for their ideal and inherent properties as a dc power source. However, the current control system generally used may be somewhat complicated due to dc voltage detection. We propose here a simple control system of the PWM converter using the power factor control in which dc voltage detection is not always needed. In this system, the dc voltage is given by the line voltage and the modulating index of the PWM converter. The principle of the PWM control system is shown at first. From the simplified circuit model and its phasor diagrams, some basic relations of the PWM converter system are obtained and some fundamental characteristics are shown. From these investigations, it is seen that the phase control region is restricted to a certain angle, which depends on the setting power factor, the modulating bypass index of the PWM and the load. Under the operating condition of unity power factor, it is given by ±π/4 for both the converting and inverting operations. The system can be operated over the all-control range of the modulating index by restricting the angle to this critical value for the angle over this control range. The ideal operating characteristics as a dc power source can be verified by some experimental results, including the operating waveforms of line current, the steady state characteristics and the transient response between both operations of the converter and inverter. In this system it is simple to construct the control circuit; it also has some inherent and excellent characteristics as a voltage fed type dc power source. This control system may be applicable to any types of PWM converter used today. 相似文献
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随着大型光伏电站装机容量的不断增加,光伏发电单元本身的光照强度、温度变化等都会引起并网电压波动甚至越限,大型光伏电站必须参与调压控制,必要时给电网提供紧急无功支撑。针对该问题,首先以某40MWp光伏发电项目为例,对线路阻抗引起的电压波动和偏差进行了量化分析,理论分析表明:随着有功输出的进一步增加,线路电抗的影响要大于线路电阻的影响,并网电压的幅值逐渐减小。在此基础上,通过对并网逆变器在不同控制方式下无功容量及其无功补偿局限性的分析,提出了适用于大型光伏电站的并网逆变器无功与电压控制策略,并对具体实现方式、无功分配方案、光伏发电单元无功优化等问题进行了深入分析。最后,通过算例仿真验证了所提无功与电压控制策略的正确性和可行性。 相似文献
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在分析了交流电源直接并联存在的不足的基础上,提出了采用三相PWM整流—并联—PWM逆变的供电模式。三相PWM整流器输出的直流电压含有谐波导致直流电压不断脉动,交流电源通过三相PWM整流器进行直流并联时,必须考虑电压脉动的影响。针对此问题,通过在整流器输出侧添加电阻的方式,抑制了电压脉动对并联稳定的影响;分析了并联模块接入时机对并联过程的影响;提出了一种实现并联条件下,单个模块输出功率自由分配的控制方式。最后,通过仿真验证了该控制方式的可行性。 相似文献
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为克服高渗透分布式电源接入所导致的传统配电网运行状态评估方法存在盲区的困难,对计及分布式电源随机特性的配电网电压质量的状态定量评估方法进行研究。首先引入一种半不变量结合Gram-Charlier级数展开的概率潮流计算方法,并建立含系统电压平均越限概率、节点电压置信区间和节点电压最大越限概率指标的评估体系。然后以分布式光伏为代表,构建了其有功出力服从Beta分布的概率模型,并定义一种改进的计及光伏波动特性的光伏渗透率指标,由此定量评估不同光伏渗透率对配电网电压质量的影响。最后验证该算法用于配电网电压质量状态评估的可行性。 相似文献
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为了满足光伏电站并网对公共连接点(Point of common coupling,PCC)无功电压控制要求,基于九区图原理,以PCC电压和功率因数均合格为最优控制目标,针对PQ电源型和PV电源型的大型光伏电站提出了的无功电压控制策略。搭建了PQ电源型和PV电源型大型光伏电站的等效模型,给出光伏电站无功电压控制策略实施流程图。以典型光伏电站出力和负荷动态变化为基础,通过搭建一个含大型并网光伏电站的110 kV系统,对光伏电站的无功电压控制进行仿真。仿真结果验证了所提策略的有效性和实用性。 相似文献
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大型光伏电站并网后,给配电网乃至输电网的电压、电能质量等带来一系列的影响。静止同步补偿器(STATCOM)可稳定公共连接点电压并提高分布式电源的低电压穿越能力。提出了一种适用于大型光伏电站角形级联STATCOM的电压控制策略,能够支撑电网正序电压,减少公共连接点电压波动,并抑制公共连接点负序电压,改善电网电压不平衡;再结合角形级联STATCOM相电流与线电压的约束关系,给出了角形级联STATCOM相电流指令获取方法;最后,在PSCAD中搭建仿真模型验证了所提控制方法的正确性和有效性。 相似文献
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针对光伏电站并网问题,分析了并网接入点的系统电压变化因素,通过建立光伏电站并网的戴维南等效电路及进一步推导,得出了系统短路容量与光伏电站极限规划设计容量及并网点电压之间的简明关系。分析结果表明:可以利用光伏电站待接入的并网点系统短路容量这一电网特性简单估算待并入光伏电站的极限设计容量大小及并网点电压的变化大小,为今后更好地规划设计光伏电站及电力系统的安全稳定运行提供参考。 相似文献