限制转子电流的双馈风电机组虚拟同步控制策略

随着新能源的大规模开发利用,其在能源结构中的占比不断提高。为了维持大电网的平稳运行,要求双馈风机等新能源机组参与电网调频。双馈风机的转子侧变流器存在容量限制,而调频过程中转子电流变化可能会超出此限。为应对这一问题,首先分析了双馈风力发电机的数学模型,并得出了额定转速下dq系的转子电流控制模型;然后使用误差转化函数与李雅普诺夫方法,设计了限制转子电流的控制器,并与常规的虚拟同步控制相结合,提出了一种改进的虚拟同步控制策略,可以兼顾风机调频的需求与调频动态过程中转子电流的限制。通过仿真验证了所提出控制器参与电网调频的能力以及对于转子电流的良好控制。     

采用定子电流与扰动观测的永磁同步电机改进预测电流控制

提出了一种采用定子电流和扰动观测补偿的改进预测电流控制(PCC)算法。理论上永磁同步电机PCC具有优异的控制性能,但现实系统中离散采样延时与电磁参数时变等问题使得原理上基于模型的预测电流控制器的控制品质严重恶化。设计了龙伯格(Luenberger)状态观测器实现对定子电流与参数扰动的观测,并应用于补偿和改进经典的无差拍预测电流控制器。将观测到的当前时刻的定子电流替代当前时刻的采样电流用于反馈控制,以补偿采样延时;运行过程中电磁参数的变化使得模型参数失配,其影响以电压扰动的形式被观测出来,并补偿到预测控制输出的电压指令中。仿真和试验结果验证了所提方法的有效性。     

永磁同步电机全域温度场分析与水道优化设计

以额定功率为60 kW永磁同步电机(PMSM)为研究对象,采用气隙等效导热系数处理定转子间的热交换问题。给出散下线定子绕组的等效热模型。在进行绕组铜耗计算时考虑温升对定子绕组阻值的影响,试验测定壳体与定子铁心间因装配间隙而产生的热阻值。在此基础上建立PMSM三维全域瞬态温度场有限元模型,计算电机在峰值转速运行时的温度场变化,并进行试验验证。对水道宽度比、水道数和翅片进行优化计算,找出最优解。结果表明,水道优化后电机最高温度下降9.8 ℃,对电机水道结构设计具有一定的指导意义。     

逆变器并联驱动永磁同步电机容错控制研究

为了提高逆变器并联驱动永磁同步电机(PMSM)系统的运行可靠性,基于对比研究方式设计了两种逆变器并联驱动PMSM的容错控制方案,分别为正常通路电流补偿方案和等效电流补偿方案。两种容错控制方案均不同于传统方案,后者将故障逆变器整体隔离,前者则充分利用了所有逆变器非故障桥臂,以降低故障条件下的铜耗,并输出平稳转矩。此外,两种新型容错控制方案均结合了比例谐振电流控制器以实现对不对称参考电流的跟踪,避免了并联逆变器之间可能出现的环流。最后,通过PMSM并联驱动系统的容错控制试验,验证了新型容错控制策略的效果。     

多通道GPS共视法时频传递接收机的研制

GPS共视法是国际上流行的远距离时间频率传递技术,核心是共视法接收机。我们成功研制了多通道GPS共视法时频传递接收机系统,硬件部分主要由自主研制的高精度时间间隔计数器和Motorola生产的VPONCORE GPS引擎组成,软件符合时间频率咨询委员会(CCTF)发布的GPS共视法数据处理软件标准化指南的要求,与单通道GPS定时接收机相比,界面更友好,操作更方便,具有很强的分析处理数据功能。经测试证明多通道GPS接收机零基线共钟共视时间比对的不确定度小于4 ns(仰角40°),与国外报道基本相同。     

调频调相应答机距离零值测量新方法

叙述了分频调制度变换器的工作原理和时延测量。提出了根据测量FM信号源大频偏调制与小频偏调制的时延差来挑选出恒时延FM信号源,采用恒时延FM调制器构成FM—PM应答机（或FM—PM测距地面站）距离零值测量方法和设备,这是FM—PM体制侧音测距系统的一种距离零值测量新方法;提出了采用分频调制度变换器和非恒时延FM信号源构成FM—PM应答机（或FM-PM测距地面站）距离零值测量方法及设备。     

基于匹配滤波和时间恢复算法的B(AC)码数字解调技术

针对靶场时间统一系统中B（AC）码解调的现状和存在的问题,本文从匹配滤波和时间恢复两个方面入手,阐述了一种B（AC）码在噪声和波形失真条件下的数字解调技术。     

Force measurement using strain-gauge balance in shock tunnel based on deep learning

When a force test is conducted in a shock tunnel, vibration of the Force Measurement System (FMS) is excited under the strong flow impact, and it cannot be attenuated rapidly within the extremely short test duration of milliseconds order. The output signal of the force balance is coupled with the aerodynamic force and the inertial vibration. This interference can result in inaccurate force measurements, which can negatively impact the accuracy of the test results. To eliminate inertial vibration interference from the output signal, proposed here is a dynamic calibration modeling method for an FMS based on deep learning. The signal is processed using an intelligent Recurrent Neural Network (RNN) model in the time domain and an intelligent Convolutional Neural Network (CNN) model in the frequency domain. Results processed with the intelligent models show that the inertial vibration characteristics of the FMS can be identified efficiently and its main frequency is about 380 Hz. After processed by the intelligent models, the inertial vibration is mostly eliminated from the output signal. Also, the data processing results are subjected to error analysis. The relative error of each component is about 1%, which verifies that the modeling method based on deep learning has considerable engineering application value in data processing for pulse-type strain-gauge balances. Overall, the proposed dynamic calibration modeling method has the potential to improve the accuracy and reliability of force measurements in shock tunnel tests, which could have significant implications for the field of aerospace engineering.     

Very low thrust station-keeping for low Earth orbiting satellites

Traditional station-keeping for Earth observation satellites with chemical thrusters generally involves maneuvers every couple months that are able to change significantly the semi-major axis and the inclination. These strategies do not scale down to very low thrust level (a few hundreds of μN) electrical thrusters. This paper presents both in-plane and out-of-plane strategies that spread corrections over very long arcs and discretize them to tiny maneuvers every couple orbits, taking into account mission-constraints on maneuvers locations. These strategies scale up to medium thrust strategies, filling the gap between propulsion technologies. The out-of-plane strategy although features a new no-deadband property and controls the full orbital momentum. All strategies allow control very close to the reference (a few hundreds meters in osculating parameters) and very low cost.