多虚拟同步机系统的自适应滑模变结构控制方法

虚拟同步机是一种可以改善分布式能源并网兼容性的技术手段。目前有关虚拟同步机滑模控制的研究大多数仅针对于单机系统。由于单机系统无需考虑多机系统中出现的虚拟惯量等参数之间的耦合影响,这导致现有的滑模变结构控制策略不适用于多虚拟同步机系统,当功率波动时系统频率有可能产生振荡。针对上述问题,提出了多虚拟同步机虚拟惯量的整定判据,并基于整定判据提出多虚拟同步机系统的自适应滑模变结构控制策略,可以使系统中各台机组在扰动状态下输出稳定频率。通过自适应滑模变结构控制策略使得多虚拟同步机组在功率波动时输出稳定的频率,从而避免系统频率失稳。最后,通过搭建PSCAD仿真模型验证了理论分析的正确性及有效性,所提控制方法可提高多虚拟同步机系统的稳定性与鲁棒性。     

Determination of the inductance of a synchronous reactive machine for sensorless control

The problem of eliminating rotor-position sensors in ac drives has been the focus of intense research for over two decades. Among the expected benefits of the solution to this problem are reduction of drive cost and size, as well as increased reliability. The methods developed for this purpose are usually called “methods of sensorless control.” It has been shown that sensorless-control methods for ac machines provide high efficiency at medium and high speeds. However, these methods are less efficient at lower speeds and control of the position at low and near-zero speeds is not possible. To overcome this limitation, methods of sensorless control based on the tracking the position of rotor asymmetries have been proposed. These methods measure the response of a machine to the high-frequency component of the excitation signal. One of the most attractive aspects of this method is the absence of limitations when operating at very low or near-zero speeds, which allows one to control the rotor position. This paper presents the results of theoretical and experimental studies of the method for determining inductances Ld and Lq in a synchronous reluctance machine (SynRM) using the injection of a high-frequency component into the stator voltage. This paper discusses the principles of this method and its application to the mathematical model of the SynRM and the M3AL 90LDA 4 engine produced by ABB Co. Determination of these parameters is necessary for the implementation of sensorless-motor-control systems.     

Small perturbation performance of a synchronous machine using d-decomposition technique

The D-decomposition method of analysis is used to determine the small perturbation response of a synchronous machine. Computed results are presented in the form of stability contour diagrams showing the boundaries of absolute stability or with arbitrary degrees of damping in terms of the parameters of a conventional proportional voltage regulator. The influence of the damping factor on system response is illustrated with time—domain characteristics.     

永磁同步发电机自适应分数阶变桨距角控制

提出了一款基于扰动观测器的分数阶比例-积分-微分(Perturbation observer based Fractional-order ProportionalIntegral-Derivative, PoFoPID)控制策略,以在永磁同步发电机(Permanent Magnetic Synchronous Generator, PMSG)高于额定风速的工况下,通过变桨距角控制,将发电机输出功率维持在其额定值附近。首先,将PMSG的系统非线性、参数不确定性和未建模动态等聚合为新的扰动,并采用扰动观测器对其进行在线估计。然后,设计分数阶PID控制对该扰动估计进行实时完全补偿,以提高系统动态特性。此外,PoFoPID控制器参数通过群天牛算法寻优获得,避免了常规PID控制参数依赖人工整定的缺陷。斜坡风速、随机风速和参数不确定算例下的仿真结果表明,与矢量控制、基于扰动观测器的PID控制和反馈线性化控制相比,所提PoFoPID控制具有满意的输出功率稳定效果。最后,基于dSpace进行的硬件在环实验(Hardware-in-loop, HIL)验证了所提方法的硬件可行性。     

直接转矩控制用于同步电机的特点综述和仿真分析

介绍了同步电机直接转矩控制的研究现状,着重分析了同步电机的直接转矩控制与异步电机的直接转矩控制的不同点,如零矢量的作用、转子的初始位置、直流偏置的影响、转速的观测等。利用MATLAB软件中的SIMULINK对同步电机的直接转矩控制系统进行建模、仿真。仿真结果表明,同步电机直接转矩控制系统性能很好。     

空调负荷虚拟同步机的负荷响应控制技术

空调负荷已经成为我国夏季用电的主要负荷之一,对电力系统的稳定运行产生了极大的威胁。负荷虚拟同步机技术可以感知电网的运行状态,在需求侧参与电网的一次调频,起到稳定电网的作用。首先,阐述了将变频空调作为负荷虚拟同步机运行,并参与电网一次调频的机理。其次,提出了空调负荷虚拟同步机负荷响应的调节策略及其功率控制方法。最后,通过仿真验证了所提出的负荷响应调节策略及其控制方法的有效性。     

A harmonic compensation brushless synchronous condenser using a cascade induction machine

In this paper, a new brushless synchronous condenser termed the BSC‐Filter is presented. It consists of two wound‐rotor induction machines connected in a cascade, and acts not only as a synchronous condenser but also as a passive filter with a capacitor connected to its stator field winding. An equivalent circuit model seen from the sixth harmonic in the field system is illustrated using the method of symmetrical coordinates. Based on this equivalent circuit model, a fundamental formula is derived to select the capacitor value properly. The validity of the theoretical analysis is verified through experiments, and basic characteristics of the BSC‐Filter are clarified. In addition to phase compensation, this new machine is capable of reducing low‐order fifth and seventh harmonics in power lines. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 71–78, 2002     

Adaptive virtual synchronous generator control using optimized bang-bang for Islanded microgrid stability improvement.

In this paper, a virtual synchronous generator (VSG) controller is applied to a hybrid energy storage system (HESS) containing a battery energy storage system and supercapacitor storage system for maintaining the frequency stability of an isolated microgrid. The microgrid contains a photovoltaic generation system and a diesel generator in addition to the HESS and two constant impedance loads that are fed through a medium voltage radial feeding system. The adaptive virtual inertia constant (H) with constant virtual damping coefcient (D) based on‘ bang-bang’ control for the microgrid’s frequency stability enhancement is investigated and compared with the constant parameter VSG. In addition, the bang-bang control is modifed to adapt the D beside the adaptive H, and the system response is investigated and compared with the conventional adaptive H technique. The VSG parameters are evaluated based on two diferent methods. The frst is a computational method based on the simplifed small signal stability analysis, while the other is based on an optimization method using two diferent objective functions and the particle swarm optimization technique. This paper also investigates the superiority of the proposed technique compared to other techniques in enhancing frequency stability, accelerating steady-state frequency restoration, and reducing the energy requirement of the HESS. The required power from the HESS is shared between the two energy storages using the low pass flter technique so as to reduce battery peak current     

双级式有功备用光伏虚拟同步机控制策略

大规模光伏并网发电导致电力系统面临惯性下降与调频能力不足的问题,迫切需要光伏系统主动参与电网频率调节。以双级式光伏拓扑结构为基础,提出有功备用跟踪的光伏虚拟同步机控制策略。DC\DC侧根据光伏单元运行的最大功率点确定系统的有功备用点,使系统运行在有功备用模式;当电网频率扰动时可调节光伏单元的有功输出来参与一次调频。逆变侧采用与同步机等效的下垂控制方案,将高压直流侧电容模拟为虚拟转子响应功率动态调节,并通过PI控制维持直流电容电压恒定。建立光伏有功调频的小信号模型,运用传递函数分析了直流电容参数对动态性能的影响。在辐照度突降、电网频率突变以及不同系统参数下进行仿真分析,证明了所提方案的有效性。     

无刷交流同步电机无位置传感器起动控制

针对无刷交流同步电机应用于飞机变频交流起动发电系统中作为起动机用存在的励磁和位置传感器问题,提出一种适用于无刷交流同步电机的无位置传感器起动控制技术.在分析单相交流励磁控制效果的基础上,结合无刷励磁同步电机工作原理,在起动初始,采用主电机感应电势法估计出转子初始位置;采用他控式加速方法,克服了无位置传感器无刷交流同步电机零速起动存在的问题;达到一定转速后,采用反电势过零点检测法获取转子位置信息,从而切换为自控式加速运行.通过实验样机验证了上述控制方法的可行性,实现了无刷交流同步电机全转速范围内的无位置传感器起动.     

Improvement of synchronous machine transient response by fast-acting phase-shift control

The transient response of a synchronous machine connected to a large system can be improved by the insertion of fast-acting phase shift. The concept is described in simple terms using the equal-area criterion and by computed results using a typical mathematical model. A strategy is then outlined to minimise the system disturbance.     

永磁同步电机单神经元自适应PID控制

通过对永磁同步电机数学模型的分析及常规控制方式的研究，利用单神经元自适应PID(Proportional Integral Differential)控制器对永磁同步电动机的转速及转矩进行调节，并进行了大量的仿真分析。研究结果表明，该控制方式具有更好的动态调节特性和自适应能力，而且控制器设计更简单，参数调整方便，易于工程应用。     

永磁同步发电机自适应分数阶PID控制设计

设计了一款新型自适应分数阶比例-积分-微分(AdaptiveFractional-Order Proportional-Integral-Derivative,AFOPID)控制,以实现永磁同步发电机(Permanent Magnetic Synchronous Generator,PMSG)的最大功率追踪(Maximum Power Point Tracking, MPPT)。首先,将发电机非线性、参数不确定性、未建模动态以及随机风速聚合成一个扰动,并通过高增益状态-扰动观测器(High-Gain State and Perturbation Observer, HGSPO)对其在线估计。随后,采用分数阶PID(Fractional-Order Proportional-Integral-Derivative, FOPID)控制对该扰动估计进行完全补偿,以实现不同工况下全局一致的鲁棒控制性能。AFOPID控制较传统PID控制而言具有更出色的MPPT性能,且其无需精确的PMSG模型,仅需测量d轴电流和机械转速,易于实现。通过阶跃风速和随机风速两个算例,对AFOPID的控制性能与PID控制、FOPID控制和反馈线性化控制(Feedback Linearization Control, FLC)进行了对比。仿真结果验证了AFOPID控制的有效性和鲁棒性。     

喂丝机自适应分布式控制系统

喂丝机是炉外精炼设备之一,它对提高钢的质量具有十分重要的意义.本文分析了喂丝机的工艺要求,论述了变频式自适应分布式控制喂丝机的结构特点,详细说明了喂丝机自适应分布式控制算法,仿真实验结果表明所设计的控制方案的有效性.通过实际应用说明,该系统有较好的经济效益和应用前景.     

Estimation of synchronous machine parameters using new discrete time-filtering algorithm

This paper presents a new method for estimating synchronous machine parameters from frequency test using a discrete time-dynamic filter based on the least absolute value parameter estimation algorithm (see G.S. Christensen and S.A. Soliman, Automatica. 26 (2) (1990) 389–395). The proposed method uses a digital set of measurements for the direct axis impedance magnitude and phase as a function of the frequency for estimating the d-axis parameters, such as the direct reactance and the different direct axis time constants, as well as the q-axis parameters.A practical example from the literature is used (see F.B. De Mello and L.N. Hannet, IEEE Trans. Power Appar, Syst., PAS-102 (12) (1983) 3810–3815) to test the proposed algorithm, and results are obtained and compared with those obtained using other methods such as the least error squares algorithm (see S.A. Soliman, S.E. Emam and G.S. Christensen, Can. J. Electr. Comput. Eng., 14 (3) (1989) 98–102) and the Kalman filtering algorithm (see M. Mambo, T. Nishiwaki, Syokokawa and Y. Ueki, IEEE Trans Power Appar. Syst., PAS-100 (7) (1981) 3304–3311).     

Identification of machine parameters of a synchronous motor

This paper presents a method for estimating the machine parameters of a synchronous motor. The presented method is equally applicable for a wound field synchronous motor, synchronous reluctance motor, or permanent magnet (PM) synchronous motor, both the interior and surface-mount types. The method works particularly well for machines having a significant amount of space harmonics, such as synchronous reluctance and interior PM (IPM) machines, where the harmonics are predominantly the slot harmonics. It is also well suited for surface PM machines operating under saturation, where the harmonics are saturation-induced. The presence of these harmonics makes the parameter identification difficult. Most of the methods presented so far in the literature have failed to properly identify machine parameters in the presence of space harmonics. In this paper, the machine parameters, identified by using a proposed algorithm, are compared with the finite element and the experimental results to demonstrate the effectiveness of the presented method. Both interior PM and surface PM machines are considered.     

永磁同步电动机转速自适应模糊Backstepping控制

针对永磁同步电动机(PMSM)参数摄动和负载干扰情况下的转速跟踪控制系统,采用自适应算法估计负载扰动、粘性摩擦系数和转动惯量,利用自适应模糊系统逼近定子电阻和电枢电感等参数摄动造成的总的不确定性,并设计一种基于Backstepping的自适应模糊控制器.通过Lyapunov稳定性理论验证所设计系统的稳定性.对PMSM转...     

含不确定参数的永磁同步电机位置自适应控制

针对永磁同步电机（PMSM）数学模型结构复杂以及含有不确定参数的问题,通过引入一个合适的状态变换,把原系统转换为工类比较规范的、易于处理的非线性系统的简单形式,再依据反步法的设计原理,给出了PMSM位置自适应控制器的设计方案。理论分析表明,该方案能够克服系统中不确定参数的影响,保证了系统全局稳定和所有信号全局有界,并且位置输出渐近跟踪参考信号;仿真结果也证实该控制器具有快速、稳定、无超调等优点,而且能够保证位置跟踪误差很快趋近于零,实现了控制精确度的要求。     

A predictive current control applied to a permanent magnet synchronous machine, comparison with a classical direct torque control

This paper presents a new predictive current control (PCC) for permanent magnet synchronous machines (PMSM) drivers. Based on a hybrid model including an inverter model and a PMSM model, the proposed scheme selects more than one inverter configuration and allows to reach exactly the reference state vector. It appears attractive when compared to conventional direct torque control (DTC). Hysteresis comparators are not used. The switching frequency is fixed and it does not have to be very high. The control scheme has been verified experimentally with a 1.6 kW PMSM drive. Comparative studies with DTC control are performed with the same test bench. The results show that the proposed control obtains the same fast torque dynamics if not better than DTC control schemes but with smaller ripples.