the paper analyzes the existing Linux virtual server (LVS) cluster load balancing algorithm and its inadequacies that not real-time dynamic full makes an appraisal to the load on the each server node, designs a new Dy...
详细信息
This paper focuses on how to help students engage better with control courses and to learn through doing. In parallel it discusses strategies for encouraging more independent learning into the curriculum. Two main ass...
详细信息
ISBN:
(纸本)9781846000386
This paper focuses on how to help students engage better with control courses and to learn through doing. In parallel it discusses strategies for encouraging more independent learning into the curriculum. Two main assumptions are made: (i) first that module design needs to embed regular student activity and (ii) student activity mostly involve more than engagement with what is covered in formal lectures. The paper is completed by student evaluations of a large group of students from three different engineering departments.
Cascaded H-Bridge rectifier (CHBR) is a more attractive solution in traction application for its transformerless structure. Because of the currents of different cells are exactly the same one, it is a challenge job to...
详细信息
ISBN:
(纸本)9788986510119
Cascaded H-Bridge rectifier (CHBR) is a more attractive solution in traction application for its transformerless structure. Because of the currents of different cells are exactly the same one, it is a challenge job to regulate the voltages of cells with only one current controller. In this paper, a PI-based control scheme is presented to deal with the voltages balance issue in CHBR. To satisfy the demand of rectifier such as unity power factor and regulated output DC voltages, the proposed control scheme consists of two parts. One is for shaping the grid current waveform and regulating the sum of DC-link voltages of all the cells;the other one is for balancing DC-link voltages. The latter is more concerned in this paper and is discussed in detail especially. Simulations and experiments are carried on. The results verified the feasibility and effectiveness of the proposed scheme.
In this paper, a novel control scheme for cascaded H-Bridge rectifier (CHBR), which can be used as the primary end of high voltage high power multilevel converters, is presented. The controller is similar with the one...
详细信息
ISBN:
(纸本)9788986510119
In this paper, a novel control scheme for cascaded H-Bridge rectifier (CHBR), which can be used as the primary end of high voltage high power multilevel converters, is presented. The controller is similar with the one for single phase rectifier. To improve the performance of the controller, notch filter and proportion resonance (PR) controller are employed and the discrete methods for them are discussed in detail. The different function of CHBR controller from the single rectifier is for voltage balancing. Therefore, the phase-disposition technology, which is used in the multilevel converter, is introduced to eliminate the voltage error from the expected value. With this approach, the states of the switches of the CHBR are decided correctly by the practical condition and then the DC-link capacitors of the cells are controlled to charge or discharge in the way which results to voltage balancing. The effectiveness of the proposed approach is verified by experimental results.
Homogeneous charge compression ignition (HCCI) is more efficient and produces significantly less NO x emissions compared to spark ignitions. Using an exhaust recompression strategy to achieve HCCI, however, produces c...
详细信息
Homogeneous charge compression ignition (HCCI) is more efficient and produces significantly less NO x emissions compared to spark ignitions. Using an exhaust recompression strategy to achieve HCCI, however, produces cycle-to-cycle coupling which makes the problem of controlling combustion phasing more difficult. In the past, a linear feedback controller designed with a single linearized model is effective in controlling combustion phasing around an operating point. However, HCCI dynamics can change dramatically around different operating points such that a single linearization is insufficient to approximate the entire operating range. Further investigation shows that the operating range can be roughly divided into three regions where a linear model can capture the qualitative system behavior in each of the regions. As a result, a three zone switching linear model approximates recompression HCCI dynamics far better than a single linearization. This new model structure also suggests that two of the three regions need completely opposite control actions. Therefore, the approach of using a static feedback control based on a single linearziation cannot be appropriate over the entire operating range. We propose a switching controller based on the switching linear model and achieve very good performance in controlling HCCI combustion phasing throughout the entire operating region. Lastly, a semi-definite programming (SDP) formulation of finding a Lyapunov function for the switching linear model is presented in order to guarantee stability of the switching control scheme.
The vibration signals of wind turbines are highly nonlinear and non-stationary due to wind turbine operation conditions that are very complicated. The signals will be more complex when a fault occurs. Aiming at these ...
详细信息
A control scheme for efficient and safe path and motion planning of industrial robots is proposed. For motion planning of robotic manipulators, an offline method is developed which generates feasible trajectories of t...
详细信息
This paper presents the application of a statistical method for model structure selection of lift-drag and viscous damping components in ship manoeuvring models. The damping model is posed as a family of linear stocha...
详细信息
The actual wind turbines are provided with adjustable speed generators, like the double feed induction generator, that are capable to work in variable speed operations. One of the main advantage of adjustable speed ge...
详细信息
The actual wind turbines are provided with adjustable speed generators, like the double feed induction generator, that are capable to work in variable speed operations. One of the main advantage of adjustable speed generators is that they improve the system efficiency compared to fixed speed generators because turbine speed is adjusted as a function of wind speed to maximize output power. However this systems requires a suitable speed controller in order to track the optimal wind turbine speed reference. In this work, it is proposed a sliding mode control for variable speed wind turbines. The robustness analysis of the proposed controller under disturbances and parameter uncertainties is provided using the Lyapunov stability theory and simulated results show that the proposed controller provides a good performance.
The redox steam-iron process, which has been discovered in the early 1900's, was finally abandoned because the degradation of the iron oxide ores within a few cycles. Recently, this process has been reconsidered, ...
详细信息
ISBN:
(纸本)9789604742271
The redox steam-iron process, which has been discovered in the early 1900's, was finally abandoned because the degradation of the iron oxide ores within a few cycles. Recently, this process has been reconsidered, due to the necessity to yield cheap and pure hydrogen. In this article, we introduce a related but improved technology. At the first stage, the inlet iron oxide for the steam-iron process is the hematite, which has to be reduced to metallic iron in a gasifier called HG, by using syngas from coke (or cellulose). The hydrogen is then produced in a cyclic process, based upon the reduction of metallic iron by means of steam. At the second stage, another hematite, at any granulation, is reduced to iron powder in a reactor called IPR, at about 570°C by using the hydrogen of HG.
暂无评论