电力电子负载逆变并网电流谐波抑制研究

为了抑制单相电力电子负载逆变侧并网电流畸变产生的谐波,在带通调节器用于电流环的基础之上,提出采用带通调节器结合扰动观测器的控制策略。该方法为经典控制与现代控制的结合,有效解决电流环前向通道的扰动对并网输出电流的干扰。首先介绍电流环带通调节器的研究背景,其次论述扰动观测器方法的基本原理及其优缺点,最后设计基于扰动观测器方法的并网电流环(Band Pass,BP)调节器控制方案以及电压环的设计。     

电网电压不平衡条件下并网逆变器的研究

采用一种具有双参数控制的结构实现并网运行和负序电流的消除,直流侧的电压控制环作为并网的基础控制,同时提取电网电压和逆变器输出电压的负序分量并加以控制,当两者相等时就可以达到消除负序电流的目的,然后对负序电压的获取以及电流的跟踪控制作了分析。最后利用Matlab/Simulink对系统进行仿真,验证了系统的可行性。     

Extraction of voltage harmonics using multi-layer perceptron neural network

This paper presents a harmonic extraction algorithm using artificial neural networks for Dynamic Voltage Restorers (DVRs). The suggested algorithm employs a feed forward Multi Layer Perceptron (MLP) Neural Network with error back propagation learning to effectively track and extract the 3rd and 5th voltage harmonics. For this purpose, two different MLP neural network structures are constructed and their performances compared. The effects of hidden layer, supervisors and learning rate are also presented. The proposed MLP Neural Network algorithm is trained and tested in MATLAB program environment. The results show that MLP neural network enable to extract each harmonic effectively.     

Multi-objective voltage and frequency regulation in autonomous microgrids using Pareto-based Big Bang-Big Crunch algorithm

Voltage and frequency regulation is one of the most vital issues in autonomous microgrids to ensure an acceptable electric power quality supply to customers. In this paper, a real-time control structure including power, voltage, and current control loops is proposed for microgrid inverters to restore voltage and frequency of the system after the initiation and load changes. The Proportional-Integral (PI) gains of the voltage controller are optimized in a real-time basis after a perturbation in the microgrid to have a fast and smooth response and a more stable system. The current controller produces Space Vector Pulse Width Modulation command signals to be fed into the three-leg inverter. The multi-objective optimization problem has objective functions of voltage overshoot/undershoot, rise time, settling time, and Integral Time Absolute Error (ITAE). The modified Multi-Objective Hybrid Big Bang-Bing Crunch (MOHBB-BC) algorithm is employed as one of efficient evolutionary algorithms in order to solve the optimization problem. The MOHBB-BC method obtains a set of Pareto optimal solutions; a fuzzy decision maker is used to pick up the most preferred Pareto solution as the final solution of the problem. Results from testing the control strategy on a case study are discussed and compared with previous works; according to them, the proposed method is able to obtain dynamic PI regulator gains to have a more appropriate response.     

基于Nyquist图的光伏并网电能质量综合补偿方法

在单相光伏并网逆变控制中,针对谐振频率高于截止频率时Bode图及其稳定判据的使用受到限制等问题,提出一种基于 Nyquist图的谐波补偿方法。该方法将Nyquist曲线到临界稳定点（－1,j0）的最短距离作为系统稳定程度的表征量,通过对矢量比例积分控制器（VPI）设计合适的相角补偿使该距离在Nyquist图中达到最大,从而提高奇次谐波补偿次数,同时避免闭环异常峰,闭环系统的稳定性和抗干扰能力得到增强。改进后的VPI控制使系统保持较高的稳定性,参数变化对系统稳定性的影响可忽略不计,因而简化了参数设计过程。理论分析和仿真结果验证了基于Nyquist图进行改进后的VPI控制策略的有效性和可行性。     

不平衡电网电压下基于量子粒子群并网变流器功率/电流协调控制

在不平衡电网电压情况下,风电系统的不脱网运行会导致系统输出功率出现波动,并网电流出现显著的谐波畸变.由于恒定的输出功率和良好的并网电流质量无法同时实现,对此,提出一种基于量子粒子群(quantum particle swarm optimization, QPSO)优化算法来实现功率/电流协调控制的方案.在电流参考值的...     

电压补偿在变频调速系统中的应用研究

针对异步电动机在恒压频比控制策略下低频启动时重载启动转矩不足的问题,提出在交交变频调速系统中采用电压补偿措施来提高电动机的带载能力;介绍了电压补偿原理及补偿值计算公式,通过仿真实验对无电压补偿和有电压补偿时的频谱、转速、转矩及电动机具有不同负载时的电压补偿效果进行了对比。仿真结果表明,电压补偿在变频调速系统中具有良好的补偿效果:①在有电压补偿的情况下,定子输出电压谐波含量较大,波形对称性较好,电动机带负载能力较强。②电动机负载越大,其稳态运行时的转速越小,而启动转矩大小不变,转速的降落基本保持恒定。     

Load compensation based on frame considering low-order dominant harmonics and distorted power system

In this paper, by considering voltage distortion and frequency variation, the control strategy of synchronous reference frame (SRF) for three-phase shunt active power filter has been improved. In the SRF compensation method a conventional low pass filter (CLPF) is used to extract the dc component of the d-axis current (I_d). Unfortunately in the presence of low-order harmonics of the load current (second and third ones), the transient response time is increased. If the amplitude of these harmonics are high, the distortions in CLPF output signal are increased, and as a result, the desired compensation cannot be achieved. In this paper to overcome this problem, a novel numerical LPF is designed and implemented based on variable forgetting factor-recursive least squares (VFF-RLS). The advantages of the proposed filter over CLPFs include independence of the load current harmonic components, fast dynamic and high accuracy of the response. Moreover, due to the malfunction of the conventional phase locked loop (PLL) in polluted and variable frequency environment, a second order generation integrator-frequency locked loop (SOGI-FLL) based on fuzzy logic controller (FLC) and wavelet transform (WT) is proposed. Effectiveness of the proposed method is evaluated with both simulations and experimental results in a three-phase power system.     

基于负载电压控制的可控串补技术研究

可控串联补偿技术（TCSC）能很好的提高电压质量和电力系统的稳定性。本文提出了一种以负载电压作为控制变量,根据其与目标电压的差值,计算晶闸管触发脉冲的触发角,从而控制无功串补容量的控制方法,并在Matlab／Simulink环境中设计了仿真系统。结果表明该控制方法能很好的提高负载电压,改善系统的暂态稳定性,对无功串补控制技术有一定的适用性。     

一种带电源电压和温度补偿的振荡器电路设计

设计了一个带电源电压补偿和温度补偿的低功耗环形振荡器电路,环形振荡器采用受限于PTAT电流的反相器和普通CMOS反相器级联结构。由于电源电压和温度对这两种反相器传播延时的影响是相反的,利用这种相反的特性使得振荡器输出频率在电源电压和温度特性上得到补偿。该电路采用0.18μm CMOS工艺,测试结果显示在5 V电源电压以及27℃温度条件下,输出频率为263 k Hz,平均电流消耗为2.5μA。在3.5 V~5.5 V电源电压和-40℃~85℃的温度变化范围内,输出频率偏差在-2.3%~6.5%范围内。     

矿用动态电压恢复器优化组合补偿策略

针对长时间电压跌落下矿用动态电压恢复器直流链路电容储能利用率较低的问题,提出了一种从完全补偿法到同相补偿法的优化组合补偿策略,即2种补偿策略之间平滑缓慢过渡,从而抑制跌落时刻的负载电压畸变,降低动态电压恢复器注入电压幅值,延长动态电压恢复器的补偿时间。实验结果表明,该策略在平衡和不平衡电压跌落条件下均能正确可靠地补偿电网电压跌落。     

一种带有曲率补偿的宽输入带隙基准源设计

在传统的一阶带隙基准电路的基础上,通过在电路中添加串联电阻和NPN型二极管并与电阻并联的方法,实现高阶曲率补偿。该电路不仅具有结构简单、使用器件少的优点,而且还能显著提高带隙基准的设计精度。另外,较宽的输入电压范围(10 V²5 V)有利于此带隙基准源应用在更宽的领域。仿真结果表明,通过华虹NEC 0.35μm BCD工艺,使用H-spice仿真软件对该电路仿真,在0℃25 V)有利于此带隙基准源应用在更宽的领域。仿真结果表明,通过华虹NEC 0.35μm BCD工艺,使用H-spice仿真软件对该电路仿真,在0℃⁸0℃温度范围内,其带隙基准的温度系数仅为0.501 ppm/℃;在10 V80℃温度范围内,其带隙基准的温度系数仅为0.501 ppm/℃;在10 V²5 V输入电压范围内,输出电压摆幅为31.49 mV。     

Energy efficient control of a stand-alone wind energy conversion system with AC current harmonics compensation

This paper presents a new energy-efficient control strategy for a variable-speed wind energy conversion system (WECS). The considered WECS is designed for dc load supply and battery charging in stand-alone applications. The batteries are charged through a three-phase full-bridge power converter. The WECS contains a vector-controlled self-excited induction generator (SEIG) coupled to a wind turbine (WT) for electric power generation on the ac side. The control algorithm proposed in this paper includes three separate optimizations: two fuzzy-logic-based optimizations, which ensure that maximum energy is extracted from both the WT and the SEIG, respectively, at all operating conditions, and also the optimization of phase current harmonics through adaptive hysteresis control. In addition, a recently developed algorithm for real-time loss calculation of a hysteresis-driven power converter is utilized to quantitatively assess the power converter losses with respect to different hysteresis bandwidth settings. The performance of the proposed control algorithm is experimentally evaluated and compared with two competing algorithms which do not involve current harmonics compensation, whereas one of them also does not involve optimization of the SEIG output power. This enables evaluation of the gain in system performance due to the introduced optimizations. The evaluation and comparison are made over a wide range of wind speeds, both in steady state and under transient conditions, by using a 1.5 kW experimental setup with the DS1103 controller board (dSPACE).     

A current-controlled oscillator with temperature,voltage, and process compensation

Microsystem Technologies - This paper presents a current-controlled oscillator (CCO) circuit design with temperature, voltage, and process compensation. A current reference biasing circuit...     

电网无功自动补偿软件的设计

介绍了一种无功补偿控制器中的软件设计。该软件设计巧妙，确保了功率因数角检测的精度，使系统具有较强的抗干扰能力。     

一种检测SSAS远端电压补偿连接状态的简单方法

空间太阳阵列模拟器(Space Solar Array Simulator,SSAS)是模拟太阳能电池板在各种负载条件下的输出特性曲线,在航天器电源系统的地面测试领域有着广泛地应用。但是在实际测试环境中,太阳阵模拟器与被测航天器电源之间较长的测试线缆,严重影响了太阳阵模拟器输出I-V曲线的模拟精度,故一般采用补偿连接线的方式对模拟器的输出电压进行远端补偿。提出了一种简单的检测远端电压补偿端子连接线的连接状态的方法,并给出归一化的故障状态判断依据。该方法不仅仅适用于太阳能电池阵列模拟器设备中,也可应用于任何大功率电源需要对输出电压进行远端电压补偿的应用场合。     

Toward intelligent transient stability enhancement in inverter-based microgrids

Neural Computing and Applications - Nowadays, the concept of multiple inverter-interfaced distributed generations (IIDGs)-based MG is recognized as a renowned notion. Encountering unexpected...     

孤岛微电网的分布式固定时间二次协调控制

孤岛微电网的下垂控制策略会导致系统稳态的频率和电压偏离额定值.为此,提出一种分布式固定时间二次协调控制策略以实现系统频率和电压的恢复控制,并实现期望的有功功率分配.所提出的控制方法能在固定时间内完成二次控制目标,而不依赖于系统的初始状态.该优势使得根据任务需求来离线预设整定时间成为可能.同时,采用固定时间Lyapunov方法分析二次协调控制系统的稳定性.最后,通过Matlab/Simulink仿真实验验证分布式固定时间二次控制策略的有效性.     

Strategic bidding using reinforcement learning for load shedding in microgrids

A microgrid is a small-scale power system for providing reliable power supply to a small community. The goal of microgrid operation is to balance the amount of power supplied and the amount of power demanded. In the islanded operation mode of a microgrid, if power requirements are larger than the power generation, load shedding is used to solve the power balance problem. Load shedding restricts the use of power by consumers. In a distributed load-shedding approach, a control center allocates the power to power consumers through a bidding process. At that time, power consumers need bidding strategies to maximize their profits. We propose an optimal bidding strategy using a Q-learning algorithm. To evaluate the performance of the proposed bidding strategy, we implemented a microgrid operation system, and an experimental analysis was performed.