共查询到20条相似文献,搜索用时 173 毫秒
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永磁直驱风力发电机(D-PMSG)通过双PWM全功率变流器实现和电网的连接,但在其运行过程中,网侧变流器的参数变化会对其控制性能造成影响,精确辨识网侧变流器参数对于提升发电系统控制性能具有重要意义。文章基于网侧变流器在d-q轴的动态方程,构建了网侧变流器的回归模型,设计了网侧变流器电气参数的带收敛因子的多新息遗忘随机梯度辨识算法,实现网侧变流器的电气参数辨识,并通过仿真实验验证了算法的有效性。 相似文献
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以基于TSMC的永磁直驱型风力发电系统为研究对象,建立TSMC并网逆变级的数学模型,提出TSMC直驱型风力发电系统的集成控制策略,将最大风能跟踪、输出功率调节、变速恒频控制通过网侧逆变级的集成控制实现,且无需进行稳定直流电压的功率平衡控制,系统控制复杂度降低。仿真结果验证了该控制策略的有效性。 相似文献
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空间矢量脉宽调制法(SVPWM)比传统的正弦脉宽调制法(SPWM)具有较高的直流电压利用率以及较低的输出波形失真度。介绍了三相逆变器的SVPWM控制算法,建立了基于PSCAD/EMTDC仿真平台的三相逆变器模型,并给出了基于PSCAD/EMTDC仿真平台的SVPWM优化控制算法。通过建立一个控制系统来进行仿真和研究,给出了仿真线电压及相电压波形。仿真结果充分显示了SVPWM技术应用于大功率场合的优点。 相似文献
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通过MATLAB/SIMULINK建立了联网逆变器的3种控制策略(滞环控制、基于SPWM调制的电流控制和基于SVPWM调制的电流控制).通过对3种控制策略的4个方面(稳态响应、电网电压谐波影响、动态响应和直流电压)来仿真对比分析3种控制策略.仿真结果表明,基于SVPWM调制的电流控制在3相联网逆变器中应用优于滞环控制和基于SPWM调制的电流控制. 相似文献
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In this paper, the reason of high-frequency leakage current in neutral point clamped photovoltaic grid-connected inverters that adopts traditional modulations is analysed. In order to solve the problem, this article puts forward two improved methods based on the three-level space vector pulse width modulation (SVPWM), which can reduce the leakage current by applying three medium vectors or using only two medium vectors and one specific zero vector to compose the reference vector. In addition, the system control method adopts the coordination control of the current inner loop and the DC voltage outer loop, which can reduce voltage fluctuation at the DC side. Thereby, the suppression of leakage current can be realised without requiring any modification on the multilevel inverter. Compared with the traditional three-level sinusoidal pulse width modulation (SPWM) and SVPWM, the two new methods are advantageous in having a stable common-mode voltage, low leakage current, and low harmonic component of grid current. The theoretical analysis and results show the effectiveness of the proposed methods. 相似文献
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Voltage source inverter (VSI) can produce single and three-phase (3P) AC voltages from a constant or variable DC voltage. There are many ways to control the VSI output voltage. Each control way produces some harmonics at the VSI output voltage. The space vector pulse width modulation (SVPWM) may be more effective than other modulation methods, e.g. harmonic injection, phase shifting, multi career pulse width modulation, in decreasing the low order harmonics (LOH). Different switching strategies (SSs) of power electronic devices in SVPWM have some specific advantages and disadvantages with regard to one another. In this paper, a comparative study between different SVPWM SSs is carried out by considering some objective functions such as total harmonic distortion (THD), power and switching losses, the ratio of the harmonic components to the fundamental component, distortion factor (DF). It is also shown that by selecting an optimized and appropriate SS for SVPWM, the harmonic orders, which are the multiples of the frequency index (FI), are eliminated. Then, to investigate the impact of variations of the capacitors voltage and switching frequency on power quality criteria, the most appropriate and optimized SS is applied to a 3P three-level (3L) neutral-point-clamped (NPC) VSI to supply a 3P load. 相似文献
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I. G. Atabaev Zh. S. Akhatov E. D. Mukhamediev Zh. Zievaddinov 《Applied Solar Energy》2016,52(3):220-225
This article presents the results of scientific–technical and engineering works on modernizing a big solar furnace (BSF) developed by the Institute of Materials Science, Academy of Sciences of the Republic of Uzbekistan, including works concerning the development of an automated control system for heliostats and the development of microprocessor local control systems for each individual heliostat that are managed by a mainframe computer with the relevant software, highly-precise sensors of the rotation angles of heliostat axes, and digital sun-tracking sensors. The system under consideration provides for a two-way command and data exchange between all local systems and the mainframe computer. This exchange will make it possible to perform the software control of the operation of each individual heliostat, including sun tracking based on a solar sensor, tracking based on mirror turning, and direct positioning, as well as to continuously monitor the heliostat field state, perform self-diagnostics, and maintain an automated heliostat field operation log. This article also describes works on modernizing mechanisms for heliostat rotation and motion control: the replacement of brush-type dc motors by more reliable asynchronous motors with inverters, installation of angular sensors, and reconstruction of rotation mechanisms. 相似文献
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Multiphase space vector pulse width modulation 总被引:5,自引:0,他引:5
Pole-phase modulation adjusts the pole-phase ratio of an induction machine and requires a multileg, multiphase inverter. This paper analyzes an n-leg, n-phase inverter, and presents techniques for n-phase space vector pulse width modulation (SVPWM). In particular, nine-phase SVPWM is developed and implemented on a nine winding induction machine. The nine-phase SVPWM is compared to nine phase sine-triangle PWM in terms of DC bus utilization. 相似文献
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This paper presents a novel and optimized switching strategy and control approach for a three-level two-quadrant chopper in a three-level Neutral point clamped (NPC) voltage source inverter (VSI) superconducting magnetic energy storage (SMES). Using the proposed switching strategy, the voltage of the inverter capacitors in SMES can be independently controlled; also, the minimum power and switching losses – as well as the proper convection – can be achieved using this same strategy. The simulation results indicate that when combined with a proportional-integral (PI) control approach the proposed switching strategy can be easily implemented in the power networks and can balance and stabilize the multi-level inverters’ capacitor voltage level. The voltage variation of the capacitors in the steady state condition is less than (0.062%) which is 15 times better than the IEEE standard requirement (1%). To investigate the effectiveness and reliability of the proposed approach in stabilizing capacitor voltage, SMES performance using the presented approach is compared with that of SMES when the capacitors of the three-level inverter are replaced with equal and ideal voltage sources. This comparison is carried out from the power-quality point of view and it is shown that the proposed switching strategy with a PI controller is highly reliable. Considering that the Space Vector Pulse Width Modulation (SVPWM) is highly effective in decreasing low order harmonics (LOH), this article utilizes this type of modulation when it is combined with the most optimized switching strategy. 相似文献
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This article deals with nonlinear model‐based control design for wind turbines. By systematically integrating several mechanical degrees of freedom in the control design model, the load mitigation potential from the proposed multivariable control framework is demonstrated. The application of the linear matrix inequality (LMI)‐based control design is discussed in detail. Apart from the commonly considered power production mode, an extended operating range to provide stabilization of the electrical grid through power tracking is considered. This control functionality allows for an evaluation of the resulting fatigue and ultimate loads for power tracking at different dynamic requirements. The results indicate that under the impact of a dedicated control scheme, this functionality is feasible with respect to the occurring loads and operational behavior of the wind turbine. 相似文献