Analysis of Maximum PowerPoint Tracking (MPPT) Adaptability in Inverters of the Three-Phase Photovoltaic Systems Integrated into the Electrical Grid of Congo-Brazzaville

This paper investigates the adaptability of Maximum Power Point Tracking (MPPT) algorithms in single-stage three-phase photovoltaic (PV) systems connected to the grid of Congo-Brazzaville and compares the attributes of various conventional, significance and novelty of controller system of the proposed of method and improved Incremental Conductance algorithms, Perturbation and Observation Techniques, and other Maximum Power Point Tracking (MPPT) algorithms in normal and partial shading conditions. Performance evaluation techniques are discussed on the basis of the dynamic parameters of the PV system although the control of this structure is relatively advanced technology but the conversion efficiency is difficult to improve due to increase in transformation series. The single stage topology has a simple topology with high reliability and efficiency because of high power consumption, but control algorithm is more complex because of its power convert main circuit a new strategy is being developed. This paper describes a method for maximum power point tracking (MPPT) in the single-stage and three single-phase PV grid-connected system. In the paper, the nonlinear output characteristics of the PV including I-V & P-V are obtained in changed solar insulations or temperature based on MATLAB, and the MPPT algorithm which is based on the P & O algorithm method, compared with Incremental Conductance, is also described, a dimensioning of the impedance adapter for better stabilization. A comparison SPWM and SVPWM control methods in the case of a grid connection applied to the electrical grid of Republic of Congo and their influences on the dynamic performance of the system and their impact in reducing the harmonic rate for better injection into the grid. The simulation model of three single-phase PV grid-connected system is built, and simulation results show the MPPT algorithm has excellent dynamic and static performances, which verifies the Incremental Conductance is effective for MPPT in the single-stage and three single-phase PV grid-connected system.

Robust Nonlinear Current Sensorless Control of the Boost Converter with Constant Power Load

The boost converter feeding a constant power load (CPL) is a non-minimum phase system that is prone to the destabilizing effects of the negative incremental resistance of the CPL and presents a major challenge in the design of stabilizing controllers. A PWM-based current-sensorless robust sliding mode controller is developed that requires only the measurement of the output voltage. An extended state observer is developed to estimate a lumped uncertainty signal that comprises the uncertain load power and the input voltage, the converter parasitics, the component uncertainties and the estimation of the derivative of the output voltage needed in the implementation of the controller. A linear sliding surface is used to derive the controller, which is simple in its design and yet exhibits excellent features in terms of robustness to external disturbances, parameter uncertainties, and parasitics despite the absence of the inductor’s current feedback. The robustness of the controller is validated by computer simulations.

Predicting of Power Quality Steady State Index Based on Chaotic Theory Using Least Squares Support Vector Machine

An effective power quality prediction for regional power grid can provide valuable references and contribute to the discovering and solving of power quality problems. So a predicting model for power quality steady state index based on chaotic theory and least squares support vector machine (LSSVM) is proposed in this paper. At first, the phase space reconstruction of original power quality data is performed to form a new data space containing the attractor. The new data space is used as training samples for the LSSVM. Then in order to predict power quality steady state index accurately, the particle swarm algorithm is adopted to optimize parameters of the LSSVM model. According to the simulation results based on power quality data measured in a certain distribution network, the model applies to several indexes with higher forecasting accuracy and strong practicability.

Study on the Horizontal Movement State of Suction Anchor Piles for Offshore Wind Power during Horizontal Pulling

The subsea anchor piles of offshore wind power floating platform structures are mainly subjected to uplift and horizontal loads, and this paper focuses on the case of horizontal loads. A three-dimensional numerical simulation study of the horizontal pullout characteristics of wind power suction anchor piles in clay layers was carried out to reveal the horizontal movement state of the anchor piles during horizontal pile pullout, the range of pile depth at the pullout point where the horizontal movement is achieved (referred to as the horizontal movement range), the relationship between the pullout load and the ultimate load during the horizontal movement, and the optimal location of the pullout point for the horizontal movement. The results show that at certain pull-out points, the anchor pile produces an overall horizontal movement state under suitable horizontal pull-out loads. The depth of the pile pull-out point for horizontal movement is in the middle and lower part of the pile, i.e. 14.2 m to 14.5 m. The horizontal pull-out load of 24,000 kN at a depth of 14.5 m within the pile horizontal movement range of 14.2m to 14.5 m is the maximum ultimate horizontal pull-out load;the optimum pull-out point depth is 14.5 m at 0.275 L (L is the pile length). For each pull-out point of the anchor pile in horizontal movement, the horizontal pull-out load in horizontal movement and the horizontal ultimate pull-out load existed and it was found that the two values were not exactly the same, the values were compared and it was found that at the optimum pull-out point the value of the ultimate horizontal pull-out load/horizontal pull-out load in horizontal movement tended to 1.

New thermal optimization scheme of power module in solid-state amplifier

The new 1 kW power module for ADS project needs the optimization of cooling design including water flow and tunnel layout, and the water flow of three tons per hour was chosen to be a goal for a 20 kW power source.According to analysis from the insertion and integrated loss, about 24 modules were integrated into the rated power. Thus, every module has a cooling flow of 2.1 L/min for RF heat load and power supply loss, which is very hard to achieve if no special consideration and techniques. A new thermal simulation method was introduced for thermal analysis of cooling plate through CST multi-physics suite,especially for temperature of power LDMOS transistor.Some specific measures carried out for the higher heat transfer were also presented in this paper.

The State Power Grid Development Ltd Corp. officially established

The establishment of the State Power Grid Development Corp Ltd(SPG) was officially announced on June 18, marking the government’s determination to form a nationwide united power network to make the best of power generating capability. The State-owned corporation, with 2.5 billion yuan ($301 million) worth of operating capital raised by the government, will be responsible for investment. construction and management of the power transmission and substation projects involved in the construction of the Three Gorges Project.

The Observation of Trends and Impacts of States Funding on Higher Education in America

The adequacy of state funding for higher education in America is vital to cultivate the qualified workforce and help in developing the state’s economy.With the economy downturn situation,whether the current state funding is adequate to the need of institutions and students is a valuable question to be investigated.This research reviewed the whole trends of state and federal support of the higher education,having analyzed the data of higher education funding for the whole state,for the institution development,and for the students and their families.With the enrollment increasing and the inflation growing,the state fund was dropping.Although states supply a greater part of funding to public universities,most of the state funding goes to community colleges and non-research public institutions.The public research institutions and undergraduate education are important components in higher education,generating changing the development for the entire society.The state should make some adjustments in distributing funding in order to keep up with the most urgent needs of the higher education and ease pressure on the institutions,and ease the financial burden on students and their families.

Anomaly-Resistant Decentralized State Estimation Under Minimum Error Entropy With Fiducial Points for Wide-Area Power Systems

This paper investigates the anomaly-resistant decentralized state estimation(SE) problem for a class of wide-area power systems which are divided into several non-overlapping areas connected through transmission lines. Two classes of measurements(i.e., local measurements and edge measurements) are obtained, respectively, from the individual area and the transmission lines. A decentralized state estimator, whose performance is resistant against measurement with anomalies, is designed based on the minimum error entropy with fiducial points(MEEF) criterion. Specifically, 1) An augmented model, which incorporates the local prediction and local measurement, is developed by resorting to the unscented transformation approach and the statistical linearization approach;2) Using the augmented model, an MEEF-based cost function is designed that reflects the local prediction errors of the state and the measurement;and 3) The local estimate is first obtained by minimizing the MEEF-based cost function through a fixed-point iteration and then updated by using the edge measuring information. Finally, simulation experiments with three scenarios are carried out on the IEEE 14-bus system to illustrate the validity of the proposed anomaly-resistant decentralized SE scheme.

A Comparative Study of the Value Orientations of Foreign Language Education Policies in China and the United States in the 21st Century

Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of foreign language education poli-cies in Chinese Mainland and the United States in the 21 st century and finds that both China and the United States have regardedtheir national interests as the essential value orientation of their foreign language education policies. To be specific,the core valueorientation of foreign language education policies in China is to enhance its cultural soft power.In contrast,the core value orienta-tion of foreign language education policies in the United States is to safeguard its national security. Through the comparison of thedifferent value orientations of foreign language education policies of the two countries, the paper provides some reference for the for-eign language education policy-making in Chinese Mainland.

Comparison of RN licensure examination: China and the United States

Having the two largest nursing workforces across the globe,both China and the United States have implemented licensure examinations to standardize the qualifications of registered nurse.China established the National Nursing Licensure Examination(NNLE)in 1995.Like the National Council Licensure Examination for Registered Nurses(NCLEX-RN)in the United States,the NNLE has become an important link in the nurse registration process and contributed a lot in quality assurance and development of nursing profession.It may be necessary for the NNLE to learn from NCLEX-RN in several aspects,including increasing the frequency of exam,providing examinees with individualized services,and continuing reforming exam content and format.By better aligning the content and format of the examination with the current nursing paradigm and clinical requirements,nurses may enter the healthcare field better prepared to care for patients.Considering the magnitude of their nursing workforce,both China and the United States have great potential to serve as a role model for other developing countries as they look towards establishing national nursing education programs.As new policies around standardized nurse education in China take form,we urge that the NNLE be included alongside curricular reforms.As these reforms are implemented,continued research will be needed to evaluate the effectiveness of curriculum and licensure exam regulations upon nurse preparedness and quality of nursing care in China.

Development of Chinese Medicine Education in the United States:Two Examples of Pacific College of Health and Science New York and Eastern School of Acupuncture and Traditional Medicine

Chinese medicine originated in China and has taken root all over the world.In the United States,Chinese medicine belongs to the category of complementary and alternative medicine and has a history of over 50 years as a recognized profession.The education of Chinese medicine is undoubtedly the foundation for the development and growth of Chinese medicine practice.In this article,we briefly introduced the history of acupuncture profession and its development in the United States.Pacific College of Health and Science New York and Eastern School of Acupuncture and Traditional Medicine were discussed and analyzed.This article aims to discuss two examples of acupuncture schools in the United States to provide an overview of the history and current development of Chinese medicine education in the United States.

Chinese Students in the United States:A study of Anxiety/Uncertainty Managing Behaviors

With The Anxiety/Uncertainty Management(AUM) Theory as framework,the paper had demonstrated an in-depth examination on Chinese students' anxiety/uncertainty managing behaviors and strategies when they are exposed to the new environment in the US.One-on-one interview was employed to analyze both the internal and external factors during their adaptation to new cultures.Further recommendations would be given for developing intercultural communication studies in Chinese students' oversea education or related other topics.