A Review of Control Methods for Inverters Parallel Operation

As the development of control theory in power electronics, kinds of control methods are used in high-voltage power supply's design. Simulation is one of the keys to verify the control method accuracy when designing a supply system. In this paper, a phase shifted control method is utilized in parallel resonant circuit, and the condition of the power electronic switch devices during the process of phase shifting and phase angle changing is analyzed. A system of 30kV high-frequency high-voltage AC power supply with phase shifted control is designed and simulated on the PSIM software. The simulation results prove the effectiveness of the control method, and the reliable design parameters of this system are presented.

There is a wide range of existing and potential control options for Striga. This paper describes and discusses many of the control options, with a focus on technology limitations, adoption limitations (real or potential) and, in the case of novel technologies, development limitations. The paper addresses the question as to why, after many years of research, control method testing, piloting and technology dissemination, the wide-scale effective control of Striga hermonthica (Del.) Benth. and Striga asiatica (L.) Kuntze is so elusive. Limitations, including variable technology reliability, poor access to control technology, costs (monetary, labour, skills) associated with control technology, limited practicality of methods and poor information, all hamper the adoption and impact of existing control methods. Some of the same issues may impact upon novel control technologies, and this needs careful consideration. Additional issues surround other potential technologies, especially so in the case of transgenic approaches. Suggestions are made as to how the impasse of effective Striga control can be overcome. More effective use of integrated control approaches, improved crop germplasm phenotyping, enhanced understanding of the host/non-host--parasite interaction and better integration and communication among the parasitic plant research, development and extension community are among the suggestions made.

Chapter 31 - Power Electronics Applications in Smart Grid

1. Theoretical Aspects of Learning Environments.- Knowledge Representation and the Learning Process: Taking Account of Developmental Features and Support Features in Interactive Learning Environments.- Reasoning Involved in Control Technology.- Cognitive Spectacles.- Language Control Language: Control Microworlds of the Mind.- What Role Is There for Control Technology in Learning with Computational Expressive Media?.- 2. Experiments and Case Studies.- 2.1. Course Contents.- Robotics and Telecommunication (Experience of the Ecole Active de Malagnou in Geneva Within the Framework of a Computerized Educational Environment).- Could the Robotics/Control Technology Be an Interdisciplinary Tool in School?.- Control Technology and the Creative Thinking Process for Teachers and Students.- 2.2. Methodology.- Integrating the Use of LEGO-LOGO into the Curriculum of a Primary School: A Case Study.- An Aesthetic of Learning Environment Design.- Situation Graphs as Tools for Ordering of Students' Thinking and Understanding of Actual Existing Servo Mechanisms.- Problems Associated with Getting Control Technology Working in Schools.- Promoting Active Learning: A Pragmatic Approach.- Workshops and Discussion about Educational Situations.- 2.3. The Teacher's Role.- Educational Uses of Control Technology.- Measuring some Cognitive Effects of Using Control Technology.- 3. Tools Developed for Control Technology.- 3.1. State of the Art.- Workshops.- Hands-on Control Technology with New LEGO Dacta Tools.- 3.2. Future Trends.- A New Development of Control Technology.- A Data Acquisition System in a Learning Environment.- Concurrent Control for Children.- Learning Mode in the Exploration of Parallelism in Pedagogical Robotics.- ActNet-A Heterogeneous Network of Actors for Learning of Parallelism, Communication, and Synchronization.

Energy and research on energy systems places a focus on all facets of electrical energy, as well as innovation in energy production and delivery, alternative resources, and efficient devices. Systems and equipment for converting, providing, and utilising energy as a kind of electricity are the subject of research initiatives. Power electronics are now a more integral part of power systems, enhancing quality and efficiency and fostering the gradual materialization of intelligent, efficient energy. Many different types of power electronics exist in power systems. The architectural study of changing electrical transformed from one medium to another is known as power electronics. Fields such as electronics reprocess or recover more than 80percent of the entire of the electricity produced at a world average rate of 3.4 billion kilowatts per hour each year. Power electronics converters, sometimes referred to as power converters or switching converters, are used to process or convert electrical energy. Electricity comes in two flavours: AC power and DC power. The distribution system is divided into AC distribution systems and DC distribution systems based on the type of power it uses. Power system analysis is an essential part of electrical power system design. Calculations and simulations are performed to verify that the electrical system, including the system components, is properly specified to perform as planned, withstand the expected stress, and be protected from failures. Advantages of Power Electronics: High power density electricity. Improved efficiency up to 99% in energy conversion. Because to its efficiency and dependability, switching power supply are also being used in medical devices with acoustically sensitive applications. Power system reliability, in general, relates to problems like service interruption and power outages. This is frequently described as a goal to try relying on codes specifically relevant to the consumer. SAIFI, SAIDI, and CAIDI are common dependability index values for US applications. DEMATEL (Decision Making Trial and Evaluation Laboratory) They are divided into analysis using the Nonmetal mineral product industry, General equipment manufacturing, Mining and washing of coal, Textile industry, Food manufacturing industry It is the interaction between the factors Visualized and assesses dependent relationships Through the structural model Also deals with identifying important. Power Electronics in Power Systems, Power Electronics in Transportation Systems, Energy Conservation, Heating & Lighting Control and Renewable Energy Integration Power Systems and Power Electronics in Power Electronics in Power Systems is got the first rank whereas is the Energy Conservation is having the Lowest rank. Power Systems and Power Electronics in Power Electronics in Power Systems is got the first rank whereas is the Energy Conservation is having the Lowest rank.

Power quality has become a common concern of customers and utilities in improving respective profits in the context of an open electricity market. Power electronics is the essential technology to control power quality in accordance with customer requirements and utility standards. This paper first summarizes power quality definitions and indices used in IEEE and IEC standards. It clarifies the problem to be solved and the role of power electronics devices. Then the overview of power quality control methods and equipments employing power electronics devices is explained. The control methodology discussed in this paper includes various schemes of future distribution and power supply system now under development.

In this paper we provide a review of the state of the art for active vibration control of axially moving materials (string and beam, etc.) in the past ten years, with particular regard to the subjects of some important active control methods of axially moving strings. First, an introduction is given to explain the aims and scope of this paper. This is followed by a comprehensive discussion of the active wave control methods presented by many investigators in the past ten years, including feedback control methods (such as the modal control method, the direct velocity feedback control method and the control method via transfer function formulation), active wave control methods combining transfer function, boundary control methods using the Lyapunov function, the variable structure control method, the adaptive control method, the vibration control of an axially moving beam and the active control of a moving material with arbitrarily varying length, etc. Finally, we conclude with a discussion of several issues for future research in this area.

To ensure the functioning of the energy system, coordination and increase the efficiency of its parts need new control mechanisms. Generation, transmission and consumption of electricity needed control mechanisms that include integration of self-organizing power and heat supply systems, built on multi-agent principle. Also they must correspond intellectual basis, monitoring and accumulation. This includes effectiveness assessment of the state and analysis of technical, technological and organizational management mechanisms. One of the main parts is interaction principles of energy systems in accordance with European Community policy at various levels at liberalized electricity market. In most developed countries, demand management programs are widely used as a means of harmonizing the modes of generation and consumption in the power supply system. The main direct methods are set in the form of electricity tariffs. Indirect methods are set in the form of programs to manage electricity demand and the possibility of their application to manage electricity demand. Methods for estimating the unevenness of the daily schedule of electricity consumption and the factors influencing the technological environment are presented. The work aims at scientific and applied problem – finding methods of estimation and features of managing the demand for electricity. The use of the proposed estimation methods of electricity consumption influence non-uniformity on the level of power supplies system losses based on Frize QF power and optimization of consumers’ operation modes in the power supply system is considered. Approaches and optimization mechanisms of the daily electricity consumption on the example of a residential complex with the possibility of energy accumulation are offered

A set of mathematical models for calculating the reliability indexes of structurally complex multifunctional combined installations in heat and power supply systems was developed. Reliability of energy supply is considered as required condition for the creation and operation of heat and power supply systems. The optimal value of the power supply system coefficient F is based on an economic assessment of the consumers’ loss caused by the under-supply of electric power and additional system expences for the creation and operation of an emergency capacity reserve. Rationing of RI of the industrial heat supply is based on the use of concept of technological margin of safety of technological processes. The definition of rationed RI values of heat supply of communal consumers is based on the air temperature level iside the heated premises. The complex allows solving a number of practical tasks for providing reliability of heat supply for consumers. A probabilistic model is developed for calculating the reliability indexes of combined multipurpose heat and power plants in heat-and-power supply systems. The complex of models and calculation programs can be used to solve a wide range of specific tasks of optimization of schemes and parameters of combined heat and power plants and systems, as well as determining the efficiency of various redundance methods to ensure specified reliability of power supply.

In this paper, a novel improved control method for Isolated asymmetric half bridge (IAHB) bi-directional converter (BDC) is proposed. Usually traditional phase-shift(PS) control method is applied in the topology. Theory analysis and simulation results show there are a big current press more than ration current and the loss will be greater under the case that the voltage of low voltage battery side and high voltage bus side are not matched. The larger the voltage error is ,the larger the current peak is .In order to solve the problem, usually a multi-wirings transformer is needed. In order to solve above problems, a improved control method i.e PWM plus phase-shift (PS) control applied for IAHB is presented. In this control method, PWM control and phase-shift control are combined. Voltage balance between the two sides of energy transport inductor can be realized automatically and the transformer can be saved. The current press and the loss are reduced and ZVS range is expanded .The operation principle of the method is analyzed, a state space average model is set up and ZVS condition is derived. The feature of converter with improved PS control and realization method are introduced. The comparison of current press under the same power and comparison of ZVS range are given. A prototype using this control method is built to verify analysis. Experimental results show the novel control method is reliable.

The object of the study is the process of operation of traction and external power supply systems as objects of inextricable interconnection while reducing energy costs in the cost of railway transportation in real time. One of the most problematic areas is the technology for choosing energy-efficient power supply schemes for railway traction networks in real time. The methods of forming and transforming graphs of complex schemes of traction and external power supply systems and building expert control systems for the implementation of energy-saving technologies of electrified railways were further developed in the work. In the course of the study, to increase the efficiency of simulation modeling of electric traction networks, the statistical characteristics of the loads of feeders that supply the final boundary sections, stations, depot access tracks, railway junctions and idle voltages on the traction substation tires were obtained. Methods of calculation and modeling of traction power supply have been developed, which take into account the inseparable relationship with power systems and allow choosing rational modes with minimal power flows and energy losses. Proposed methods of managing the modes of operation of the traction power supply system based on a vague description of their states and an expert system that allow solving new problems. Including, the choice of energy-saving power supply schemes in the case of power flows, economic modes of network operation in case of intensification of the transportation process. Thanks to this, ways of reducing power consumption and minimizing energy losses of traction power supply systems are proposed, which allow minimizing power flows and power losses by adjusting load flow parameters and voltage levels of traction substations. And also to increase the energy efficiency of electrified railway lines. The technique of technical and economic feasibility of power supply schemes of traction networks and evaluation of the possibility of switching to cantilever or loop power supply schemes with parallel connection points has been developed. The implemented recommendations save about 25 thousand kWh per 1 km of two-track section.

99/01170 Interaction of carbon dioxide with methane on oxide catalysts : Krylov, O. V. et al. Catal. Today, 1998, 42, (3), 211–215

A improved control method i.e PWM plus phase-shift (PS) control applied for IAHB is presented. In this control method, PWM control and phase-shift control are combined. Voltage balance between the two sides of energy transport inductor can be realized automatically and the transformer can be saved. The current press and the loss are reduced and ZVS range is expanded. The operation principle of the method is analyzed, a state space average model is set up and ZVS condition is derived. The feature of converter with improved PS control and realization method are introduced. The comparison of current press under the same power and comparison of ZVS range are given. A prototype using this control method is built to verify analysis. Experimental results show the novel control method is reliable.

Power electronic devices are important in almost all industrial sectors. Power converters are used for electric drive systems in the production of an automation industry, in the automotive industry, as power supplies in telecommunications or for power conversion in power supply systems. For testing such electronic equipment, hardware-in-the-loop simulation is almost a standard method today, especially in the automotive industry, which always requires a real-time simulation of the plant. For testing the electronic control units of power electronics, real-time capable models of power electronic circuits need to be developed, accordingly. In the previously published contribution [10] different modeling methods were described and an algorithm was developed, which can be used to simulate power electronic circuits in real-time. Based on this algorithm and the automated generation of such models ([10]), further improvements for reducing the memory usage, increasing the degree of parallelization and improving accuracy are described in this paper. However, the presented approaches and modifications as well as the studies on correction methods for switching events and the preprocessing can be applied to other algorithms.

An AMB is not widely used because of its high cost and because its dimensions are significantly larger than those of mechanical bearings. Since a 6 salient-pole type AMB has fewer poles than the usual 8 salient-pole type AMB, it is easier and less costly to miniaturize. However, because the magnetic circuit is not independent in the x and y directions, bearing forces for coil currents become complicated. To solve this problem, two control methods have been proposed. One is a minimum energy control method, which minimizes copper loss in coils. The other is a maximum bearing force control method, which generates a larger bearing force than that of the minimum energy control method. In this study, the two control methods are introduced and rotational tests are carried out for comparison. The rotor could rotate up to 53,000 rpm with the minimum energy control and maximum bearing force control methods. Moreover, rotational tests were carried out with attaching a weight to the rotor. The rotor could rotate up to 42,000 rpm and 38,000 rpm with the minimum energy control method and maximum bearing force control method, respectively. Experimental results show that the minimum energy control method provides less power consumption than the maximum bearing force control method. On the other hand, the maximum force control method provides smaller maximum coil current than that of the minimum energy control method.