针对分布式电源并网逆变器的虚拟同步发电机控制策略及其在微电网中的应用进行研究。建立并网逆变器用虚拟同步发电机控制方案的数学模型，研究基于虚拟转矩和虚拟励磁的并网有功、无功调节方案，定量分析系统模型参数摄动对并网功率跟踪的影响，详细分析惯性和阻尼参数的整定方法，提出一种基于锁相环的虚拟同步发电机离/并网无缝切换控制策略，可模拟同步发电机的准同期并列装置。最后，针对一个典型微电网系统，利用PSCAD/EMTDC的仿真结果和一台50 kVA样机的实验结果验证所提控制策略的正确性和有效性。结果表明，所提的并网功率调节控制策略具有较好的有功、无功跟踪性能；同时，还能很好地为系统提供惯性和阻尼，提高系统稳定性，此外，还能满足微电网不同运行模式之间的无缝切换。

针对分布式电源并网逆变器的虚拟同步发电机控制策略及其在微电网中的应用进行研究。建立并网逆变器用虚拟同步发电机控制方案的数学模型，研究基于虚拟转矩和虚拟励磁的并网有功、无功调节方案，定量分析系统模型参数摄动对并网功率跟踪的影响，详细分析惯性和阻尼参数的整定方法，提出一种基于锁相环的虚拟同步发电机离/并网无缝切换控制策略，可模拟同步发电机的准同期并列装置。最后，针对一个典型微电网系统，利用PSCAD/EMTDC的仿真结果和一台50 kVA样机的实验结果验证所提控制策略的正确性和有效性。结果表明，所提的并网功率调节控制策略具有较好的有功、无功跟踪性能；同时，还能很好地为系统提供惯性和阻尼，提高系统稳定性，此外，还能满足微电网不同运行模式之间的无缝切换。

The Schmallenberg virus (SBV) is an orthobunyavirus that causes abortions, stillbirths, and congenital defects in pregnant sheep and cattle. Inactivated or live attenuated vaccines have been developed in endemic countries, but there is still interest in the development of SBV vaccines that would allow Differentiating Infected from Vaccinated Animals (DIVA). Therefore, an attempt was made to develop novel DIVA-compatible SBV vaccines using SBV glycoproteins expressed in baculovirus. All vaccines and phosphate buffered saline (PBS) controls were prepared with adjuvant and administered subcutaneously to cattle at 6 month of age. The first trial included 2 groups of animals vaccinated with either carboxyl-terminus glycoprotein (Gc) or PBS and boosted after 2 weeks. In the second trial, 3 groups of cattle were administered either Gc, Gc and amino-terminus glycoprotein (Gn), or PBS with a booster vaccination after 3 weeks. The animals were challenged with SBV 9 days after the booster vaccination in the first study, and 3 weeks after the booster vaccination in the second study. Using a SBV Gc-specific enzyme-linked immunosorbent assay, antibodies were first detected in serum samples 14 days after the first vaccination in both trials, and peaked on days 7 and 9 after the booster in the first and second trials, respectively. Low titers of neutralizing antibodies were detected in serum from only 3/6 and 2/4 animals in the first and second trial, respectively, at 14 days after the first vaccination. The titers increased 2 to 3-fold after the booster vaccination. SBV-specific RNA was detected in the serum and selective tissues in all animals after SBV challenge independent of vaccination status. The SBV candidate vaccines neither prevented viremia nor conferred protection against SBV infection.

Neutron detection is crucial for particle physics experiments, nuclear power, space and international security. Solid state neutron detectors are of great interest due to their superior mechanical robustness, smaller size and lower voltage operation compared to gas detectors. Gallium nitride (GaN), a mature wide bandgap optoelectronic and electronic semiconductor, is attracting research interest for neutron detection due to its radiation hardness and thermal stability. This work investigated thermal neutron scintillation detectors composed of GaN thin films with and without conversion layers or rare-earth doping. Intrinsic GaN-based neutron scintillators are demonstrated via the intrinsic ¹⁴N(n, p) reaction, which has a small thermal neutron cross-section at low neutron energies, but is comparable to other reactions at high neutron energies (>1 MeV). Gamma discrimination is shown to be possible with pulse-height in intrinsic GaN-based scintillation detectors. Additionally, GaN-based scintillation detector with a ⁶LiF neutron conversion layer and Gd-doped GaN detector are compared with intrinsic GaN detectors. These results indicate GaN scintillator is a suitable candidate neutron detector in high-flux applications.

In this paper, the idea of operating an inverter to mimic a synchronous generator (SG) is motivated and developed. We call the inverters that are operated in this way synchronverters. Using synchronverters, the well-established theory/algorithms used to control SGs can still be used in power systems where a significant proportion of the generating capacity is inverter-based. We describe the dynamics, implementation, and operation of synchronverters. The real and reactive power delivered by synchronverters connected in parallel and operated as generators can be automatically shared using the well-known frequency- and voltage-drooping mechanisms. Synchronverters can be easily operated also in island mode, and hence, they provide an ideal solution for microgrids or smart grids. Both simulation and experimental results are given to verify the idea.

由于受到微电网线路阻抗特性等因素的影响，传统的下垂控制存在无功出力难以按照下垂增益分配的问题。分析分布式电源无功出力与空载输出电压之间的关系，并在此基础上提出基于二级控制的微电网无功控制策略。该方案利用无功出力分配关系和空载输出电压的偏离程度构造势函数。微电网中央控制器根据势函数对各分布式电源的空载输出电压进行集中调整，达到改善无功出力分配的目的。仿真结果表明该方案具有良好的动态响应特性和稳态性能。此外，用正则环流无功概念来考察不同负荷水平对分布式电源无功出力分配的影响，进一步验证了所提方案的有效性。

由于受到微电网线路阻抗特性等因素的影响，传统的下垂控制存在无功出力难以按照下垂增益分配的问题。分析分布式电源无功出力与空载输出电压之间的关系，并在此基础上提出基于二级控制的微电网无功控制策略。该方案利用无功出力分配关系和空载输出电压的偏离程度构造势函数。微电网中央控制器根据势函数对各分布式电源的空载输出电压进行集中调整，达到改善无功出力分配的目的。仿真结果表明该方案具有良好的动态响应特性和稳态性能。此外，用正则环流无功概念来考察不同负荷水平对分布式电源无功出力分配的影响，进一步验证了所提方案的有效性。

微网技术可有效整合不同类型新能源及可再生能源分布式发电的优势, 为新能源及可再生能源分布式并网发电的规模化应用提供有效可行的技术途径. 微网多样的运行方式与高质量的电力服务, 离不开灵活与稳定的控制系统, 而对微电源输出有功、无功的独立控制问题亟待研究. 针对微网线路参数特点引起的有功无功耦合问题, 提出了基于相对增益分析的目标函数对角化微网功率解耦控制方法, 将相对增益分析方法应用于低压微网线路功率模型的配对选择, 量化控制通道耦合度, 应用目标函数对角化的解耦方法, 最终实现微网线路有功功率和无功功率的独立控制. 仿真实验表明, 提出的解耦方法解决了微网线路功率耦合问题, 可实现微网系统有功、无功功率的独立灵活调节.

微网技术可有效整合不同类型新能源及可再生能源分布式发电的优势, 为新能源及可再生能源分布式并网发电的规模化应用提供有效可行的技术途径. 微网多样的运行方式与高质量的电力服务, 离不开灵活与稳定的控制系统, 而对微电源输出有功、无功的独立控制问题亟待研究. 针对微网线路参数特点引起的有功无功耦合问题, 提出了基于相对增益分析的目标函数对角化微网功率解耦控制方法, 将相对增益分析方法应用于低压微网线路功率模型的配对选择, 量化控制通道耦合度, 应用目标函数对角化的解耦方法, 最终实现微网线路有功功率和无功功率的独立控制. 仿真实验表明, 提出的解耦方法解决了微网线路功率耦合问题, 可实现微网系统有功、无功功率的独立灵活调节.

The conventional microsource wireless droop control base on “power-voltage-current” close loop is widely used. The power sharing performance of this method is significantly affected by the resistive line impedance. This paper analyzes the effectiveness of two existing solutions: the adjustment method by choosing proper control parameters has limited regulating range, which means a poor performance; the virtual impedance control method has a wide range. But it has the problem of voltage sag, this paper provides an improved method with no Q-V power close loop. This method simulates the virtual impedance as the virtual synchronous generator inductance; uses the virtual impedance voltage to realize the microsource Q-V voltage droop characteristic, which can save the microsource voltage sag amplitude. Finally, simulation results and experimental results on the parallel inverter are provided to prove the performance of this new control method.

The conventional microsource wireless droop control base on “power-voltage-current” close loop is widely used. The power sharing performance of this method is significantly affected by the resistive line impedance. This paper analyzes the effectiveness of two existing solutions: the adjustment method by choosing proper control parameters has limited regulating range, which means a poor performance; the virtual impedance control method has a wide range. But it has the problem of voltage sag, this paper provides an improved method with no Q-V power close loop. This method simulates the virtual impedance as the virtual synchronous generator inductance; uses the virtual impedance voltage to realize the microsource Q-V voltage droop characteristic, which can save the microsource voltage sag amplitude. Finally, simulation results and experimental results on the parallel inverter are provided to prove the performance of this new control method.

For conventional droop control，it is difficult to keep rated frequency or voltage amplitude within small deviations in island operation mode when the load changes，and it is also difficult to keep constant power output in the grid-connected operation mode when the frequency or voltage amplitude of the grid fluctuates.To address these problems，a droop controller with adaptive drooping coefficient adjustment is designed to remove static deviations in frequency and maintain small deviations in voltage amplitude in island mode and to maintain constant power output in grid-connected mode.Moreover，a multiple master-slave control strategy is proposed based on the droop controller to overcome the shortcomings of the master-slave microgrid system control and the multiple master microgrid system control based on V/f.MATLAB/Simulink simulation shows that the proposed droop controller and multiple master-slave control strategy are feasible and effective.

For conventional droop control，it is difficult to keep rated frequency or voltage amplitude within small deviations in island operation mode when the load changes，and it is also difficult to keep constant power output in the grid-connected operation mode when the frequency or voltage amplitude of the grid fluctuates.To address these problems，a droop controller with adaptive drooping coefficient adjustment is designed to remove static deviations in frequency and maintain small deviations in voltage amplitude in island mode and to maintain constant power output in grid-connected mode.Moreover，a multiple master-slave control strategy is proposed based on the droop controller to overcome the shortcomings of the master-slave microgrid system control and the multiple master microgrid system control based on V/f.MATLAB/Simulink simulation shows that the proposed droop controller and multiple master-slave control strategy are feasible and effective.

Cranial base procedures involve manipulation of small, delicate and complex structures in the fields of otology, rhinology, neurosurgery and maxillofacial surgery. Critical nerves and blood vessels are in close proximity of these structures. Augmented reality is an emerging technology that can revolutionize the cranial base procedures by providing supplementary anatomical and navigational information unified on a single display. However, the awareness and acceptance of possibilities of augmented reality systems in cranial base domain is fairly low. This article aims at evaluating the usefulness of augmented reality systems in cranial base surgeries and highlights the challenges that current technology faces and their potential solutions. A technical perspective about different strategies employed in development of an augmented realty system is also presented. The current trend suggests an increase in interest towards augmented reality systems that may lead to safer and cost-effective procedures. However, several issues need to be addressed before it can be widely integrated into routine practice.

These days, distributed generators (DGs), such as photovoltaic, wind turbine, and gas cogeneration systems have attracted more attention than in the past. DGs are often connected to a grid by power inverters. The inverters used in DGs are generally controlled by a phase-locked loop (PLL) in order to be synchronized with the grid. In a stability point of view, the power system will be significantly affected if the capacity of inverter-based DGs becomes larger and larger. The concept of the virtual synchronous generator (VSG), which is used to control inverters to behave like a real synchronous generator, can be considered as a solution. The VSG can produce virtual inertia from energy storage during a short operation time, and the active power can be produced by a VSG similar to a synchronous generator. In this paper, an oscillation damping approach is developed for a DG using the VSG. The method is confirmed analytically, and verified through computer simulations. Finally, some laboratory experiments are conducted using 10-kW inverters and a transmission-line simulator.

This paper presents a new control topology to enable effective integration of voltage source converters (VSCs) in weak grids. The controller has two main parts. The first part is a linear power-damping and synchronizing controller which automatically synchronizes a VSC to a grid by providing damping and synchronizing power components, and enables effective full power injection even under very weak grid conditions. The controller adopts cascaded angle, frequency and power loops for frequency and angle regulation. The controller emulates the dynamic performance of synchronous machines, which eases grid integration and provides a virtual inertia control framework for VSCs to damp power and frequency oscillations. Although the linear controller offers stable and smooth operation in many cases, it cannot ensure system stability in weak grids, where sudden large disturbances rapidly drift system dynamics to the nonlinear region. To overcome this difficulty, a supplementary nonlinear controller is developed to assist the linear controller and enhance system performance under large-signal nonlinear disturbances, such as self-synchronization, disturbances in grid frequency and angle, high power injection in very weak grids and fault-ride-through conditions.

With the help of energy storage, synchronous generator model used in conventional power system being applied in renewable energy generation is called virtual synchronous generator (VSG) and presented in this paper. Through designing prime motor controller and excitation controller , renewable energy station with VSG can obtain the well-known frequency and voltage drooping mechanisms, and mimics a characteristic of system dynamic performance influenced by rotor inertia. It can solve the problems of low output impedance and low damp on conventional power converter, and improve the stability of renewable power generation system. The simulation and experimental results show that the proposed VSG algorithm is suitable to micro grid.（The simulation and experimental results show that the proposed VSG can simulate the characteristics of real synchronous generator.）

With the help of energy storage, synchronous generator model used in conventional power system being applied in renewable energy generation is called virtual synchronous generator (VSG) and presented in this paper. Through designing prime motor controller and excitation controller , renewable energy station with VSG can obtain the well-known frequency and voltage drooping mechanisms, and mimics a characteristic of system dynamic performance influenced by rotor inertia. It can solve the problems of low output impedance and low damp on conventional power converter, and improve the stability of renewable power generation system. The simulation and experimental results show that the proposed VSG algorithm is suitable to micro grid.（The simulation and experimental results show that the proposed VSG can simulate the characteristics of real synchronous generator.）