共查询到20条相似文献，搜索用时 546 毫秒
1.
A novel direct-drive type wind power generation system based on hybrid excitation synchronous machine (HESM) is introduced
in this paper. The generator is connected to an uncontrollable rectifier, and a fully controlled voltage-source inverter is
used to connect the system to utility grid. An intermediate DC bus exists between the rectifier and inverter. A new control
strategy is proposed which achieves the maximum power point tracking (MPPT) with the control of excitation current of HESM
and stabilizes the DC link voltage with the control of inverter output current simultaneously. Specially-designed buck circuit
is used to control the excitation current of HESM, and grid voltage-oriented vector control strategy is employed to realize
the decoupling of the inverter output power. Simulation results and experiment in 3 kW lab prototype show an excellent static
and dynamic performance of the proposed system. 相似文献
2.
为了消除电力电子装置产生的谐波,提出了一种基于有功能量平衡控制的单相有源滤波器的设计方法.该方法不需要应用传统的检测方法,只需对电源电流和滤波器直流侧电压进行采样控制即可实现谐波补偿.本文对这种方案的双闭环控制系统进行了校正分析,应用Saber仿真软件对该方案进行了验证,并设计了实验样机.仿真与实验结果表明该方法可将谐波畸变率控制在10%以内. 相似文献
3.
Grid-connected inverter for wind power generation system 总被引：3，自引：0，他引：3
In wind power generation system the grid-connected inverter is an important section for energy conversion and transmission, of which the performance has a direct influence on the entire wind power generation system. The mathematical model of the grid-connected inverter is deduced firstly. Then, the space vector pulse width modulation (SVPWM) is analyzed. The power factor can be controlled close to unity, leading or lagging, which is realized based on PI-type current controller and grid voltage vector-oriented control. The control strategy is verified by the simulation and experimental results with a good sinusoidal current, a small harmonic component and a fast dynamic response. 相似文献
4.
一体化电子式电流电压互感器研究 总被引：7，自引：1，他引：7
A high-performance current and voltage measurement system has been developed in power system.The system is composed of two parts:one current measurement element and one voltage measurement element.A Rogowski coil and a capacitive voltage divider are used respectively for the line current and voltage measurements.Active electronic components are used to modulate signal,and power supply for these components is drawn from power line via an auxiliary current transformer,Measurement signal is transmitted y optical fibers,which is resistant to electromagnetic induction and noise,With careful design and the use of digital signal processing technology,the whole system can meet 0.5% accuracy for metering and provides large dynamic range coupled with good accuracy for protective relaying use. 相似文献
5.
为了智能测量和研究直流稳压电源、蓄电池等电源的负载特性,设计了一台以TI公司的16位超低功耗单片机MSP430F169为中心控制的直流电子负载。外置16位D/A转化芯片ADS1115实时高精度采样电源电压和电流信号,经过单片机程序控制,单片机内置12位D/A转换电路输出一个直流信号并经过运放放大后驱动功率MOS管工作。MOS管作为功率消耗元件,整个电路构成了电压和电流闭环调节系统,可工作于恒压和恒流2种模式。被测电源的输出电压、输出电流和负载调整率可以实时测量并显示在图形液晶显示屏上,电流和电压的测量精度可达（0.02%±0.02%FS）。电子负载人机交互友好,测量精度高,单片机外围电路简单,可靠性高,扩充性好,具有很强的实用价值。 相似文献
6.
This paper proposes an analysis and a direct power control （DPC） design of a wind turbine driven doubly-fed induction generator （DFIG） under unbalanced network voltage conditions. A DFIG model described in the positive and negative synchronous reference frames is presented. Variations of the stator output active and reactive powers are fully deduced in the presence of negative sequence supply voltage and rotor flux. An enhanced DPC scheme is proposed to eliminate stator active power oscillation during network unbalance. The proposed control scheme removes rotor current regulators and the decomposition processing of positive and negative sequence rotor currents. Simulation results using PSCAD/EMTDC are presented on a 2-MW DFIG wind power generation system to validate the feasibility of the proposed control scheme under balanced and unbalanced network conditions. 相似文献
7.
郑莹莹 《广东广播电视大学学报》2012,21(4):108-111
一种新型氦氖激光器电源以直流12V输入,并采用开关电源逆变、倍压整流等技术;摒弃了传统的大电阻恒流的方式,采用了负反馈电路控制电流,减少了功耗,且稳流精度高于2％;还增加了稳功率电路,稳功率精度可达3％以上。 相似文献
8.
随着电力电子技术的不断发展,可控整流电路在直流电动机控制、可变直流电源、高压直流输电等方面得到广泛应用。本文建立了基于MATLAB的单相桥式整流电路、三相全控桥式整流电路的动态模型,给出了仿真实例与仿真结果,验证了模型的正确性,并展现了MATLAB仿真具有的快捷、灵活、方便、直观等优点,从而为电力电子电路的教学及设计提供了有效工具。 相似文献
9.
A new PWM converter based on soft-switching is introduced.The converter uses a minimum number of devices,and requires less switching operations than conventional techniques,Switching is realized solely in a ZVS)zero voltage switching)mode,therefore the loss is reduced and EMI(electromagnetic interference)is suppressed.The paper analyzes the operation of ZVS,and discusses the methods for maintaining a unit power factor and constant DC voltage.Changing the modulation index M and the phase angle θ keeps the input current in phase with the voltage.It also keeps the current sinusoidal,and ensures a constant output voltage. 相似文献
10.
针对很多无线供电应用场合需要保持输出电压恒定的需求,提出了一种高频逆变器前动态调压的恒压输出控制方法。以LCL-S型感应耦合电能传输系统为研究对象,通过阻抗分析法建模,发现通过元器件的参数配置,可使系统输入阻抗为纯阻性,减少无功分量,同时逆变器开关管实现了零电流开通与关断,但此时系统输出电压并不恒定。针对分析结果提出基于模糊自适应PI控制算法的逆变前动态调压控制的恒压输出控制方案,最后搭建了仿真实验平台和实验样机证明了分析结果的正确和控制方案的有效。 相似文献
11.
This paper describes a prototype power delivery system developed for high voltage electronic current transformer (ECT) that uses laser light to transfer power to and communicates with the primary converter. The design is based on optical-to-electrical power converters, solid-state diode lasers and optical fibers. Command signals are transmitted via the same up-fiber used to send power from secondary power supply to primary converter. The upward data transmission is completed during the brief interruption of power delivery without affecting steady power-supply. A simple comparator added to the primary converter can take the command data. Experimental results show that the fibers can provide reliable up-link for data transmission at 200 kb/s from the secondary to the primary converter. Based on the delivery system, the secondary converter can control three auxiliary channels to provide additional information. These monitoring channels are used in a time-multiplexing mode to provide information about the operation temperature, voltage and current at the remote unit for monitoring the ECT. This preventive maintenance or built-in test can increase reliability by giving early warning for necessary maintenance request. 相似文献
12.
孙韬 《重庆大学学报(英文版)》2005,4(1):15-18
1 Introduction In the past 20 years with the rapid development of VLSI (very large scale integration) circuits and continual spread of electric power system scale, theories on transmission lines have become an important research field where finding the analytic solutions to lossy transmission line equations remains a tough nut. Since the mathematical tool cannot provide effective help, there is no universal method to solve transmission line equations [1]. A number of researchers have obtaine… 相似文献
13.
本研究了用MCS-96系列80C196KB单片机为基础结合外围器件来实现对可控硅三相全控桥的触发控制。采用锁相环技术及过零触发的方法，实现触发脉冲与电源信号(线电压)的同步，提高了触发器的抗干扰能力。改善了三相触发脉冲的对称性。由软件控制可产生不同顺序的6组触发脉冲。 相似文献
14.
15.
Design of ERT system 总被引：2，自引：0，他引：2
INTRODUCTION Electrical resistance tomography (ERT) is a technique producing images based upon variations in conductivity, and has great potential in process ap- plications (Tapp et al., 2003). In an ERT system, current is injected to a pair of drive electrodes and voltage measurements are taken between sense elec- trode pairs, yielding resistance information for image reconstruction (Cilliers et al., 2001). Traditional ERT systems usually use high fre- quency sinusoidal waveforms as … 相似文献
16.
This paper proposes a current control scheme for a grid-connected pulse width modulator （PWM） voltage source converter （GC-VSC） under imbalanced and distorted supply voltage conditions. The control scheme is implemented in the positive synchronously rotating reference frame and composed of a single proportional integral （PI） regulator and multi-frequency resonant controllers tuned at the frequencies of 2ω and 6ω, respectively. The experimental results, with the target of eliminating the active power oscillations and current harmonics on a prototype GC-VSC system, validate the feasibility of the proposed current control scheme during supply voltage imbalance and distortion. 相似文献
17.
蔡顺燕 《四川教育学院学报》2014,(11):110-113
设计了一种输入电压为5.5V～25V,输出电压为5V的直流稳压电源及其漏电保护装置系统.直流稳压电源模块采用达林顿管TIP42、OP07运算放大器及三极管构成一个深度负反馈稳压电路.输出电压经ADS1286转换为数字量后送入单片机采样输出电压,经霍尔电流传感器CSM002A、跟随器OP07后,送入ADS1286,转换为数字量后送入单片机采样负载电流.由软件程序计算功率,并在液晶上显示.通过采样负载电流与总电流的差值实现漏电检测,并进行漏电保护.经测试,系统电压调整率Su≤1％,负载调整率SL≤1％,5.5V ～ 25V输入,输出为5±0.05V. 相似文献
18.
高压直流输电作为一种新兴发展输电方式,具有线路输电能力强、低损耗、双侧交流系统不需同步运行、发生故障时对电网造成的低损耗等优点,高压直流输电系统控制器是输电系统正常运行的有力保证,能够满足我国的输电要求。针对换流器整流部分使用PI控制器,构建高压直流输电系统模型,并通过MATLAB仿真确定基于PI控制器的高压直流输电系统智能控制器。 相似文献
19.
CHEN Xiao-fei ZOU Xue-cheng LIN Shuang-xi LIU Zheng-lin JIN Hai 《浙江大学学报(A卷英文版)》2007,8(8):1346-1350
An integrated laser diode driver(LDD) driving an edge-emitting laser diode was designed and fabricated by 0.35 μm BiCMOS technology. This paper proposes a scheme which combines the automatic power control loop and temperature com-pensation for modulation current in order to maintain constant extinction ratio and average optical power. To implement tem-perature compensation for modulation current,a novel circuit which generates a PTAT current by using the injecting base current of a bipolar transistor in saturation region,and alternates the amplifier feedback loop(closed or not) to control the state of the current path is presented. Simulation results showed that programmed by choice of external resistors,the IC can provide modu-lation current from 5 mA to 85 mA with temperature compensation adjustments and independent bias current from 4 mA to 100 mA. Optical test results showed that clear eye-diagrams can be obtained at 155 Mbps,with the output optical power being nearly constant,and the variation of extinction ratio being lower than 0.7 dB. 相似文献
20.
新能源光伏发电并网系统中的逆变器、非线性负载以及变压器等器件产生的谐波,会影响电能质量和安全。为了抑制系统中的谐波,使输出电流很好地跟踪并网电压,实现输出电流的稳定性,提出一种带锁相环和电压反馈双电流环的LCL型光伏并网逆变器谐波抑制方法。对逆变器控制系统进行分析,建立数学模型,通过MATLAB/Simulink搭建仿真系统。仿真结果证明:该方法可以有效抑制谐波,提高电能的供电质量,满足新能源光伏并网系统对电流谐波畸变率的要求。 相似文献