Advanced Materials Research Vol. 852

Abstract: This paper proposes a hydraulic sleepless speed system for a invariable fertilizing application based on PLC, in order to enhance the stability of the hydraulic sleepless speed system and eventually achieve precise fertilizing. With particular emphasis on the stability of the hydraulic circuit and the actuation control method, mathematical model and simulation model for hydraulic sleepless speed system are established. More specifically, hydraulic sleepless speed system with stable oil circuit and oil pressure sensor is designed to ensure hydraulic system stability, while PID control algorithm is employed to compensate transmission error according to the mathematical model. The hydraulic sleepless speed system is then simulated in different PID control parameters. Simulations show that the results are reasonable and applicable, providing some theoretical guidance to the characteristics anticipation and test of hydraulic sleepless speed system. It is also found that when the PID parameter is chosen as =10, =0.08, =8, the fertilizing precision will be satisfied.

Abstract: Solar photovoltaic power generation, as a kind of clean and environmental protection of green energy, is the recent much-needed supplement energy, is the basis of the future energy structure. Based on the semiconductor photovoltaic effect of photovoltaic power generation technology, can satisfy the needs of human beings. In this paper, based on rural residential distributed photovoltaic, 3 kw photovoltaic roof is introduced systematically the principle, classification and the hardware equipment, the working principle of the inverter was discussed several common method of maximum power tracking.

Abstract: The stability of generator excitations and SVCs in power system with wide-area time-delay coordinating Control is investigated in this paper. A nonlinear time-delay Hamiltonian model of power system with SVCs is constructed and the Hamiltonian functional method is used to derive a delay-dependent steady stability criterion in term of matrix inequalities by constructing suitable Lyapunov-Krasovskii functional. Then the wide-area damping controller (WADC) and wide-area damping supplementary controller (WDSC) for the power system is designed based on the delay-dependent sufficient conditions. Four-generator eleven-bus power system is used to illustrate delay effect on inter-area mode damping. The performance of the proposed controller is verified by the results of simulation in time-domain, and it is proved that the method proposed in this paper is effective.

Abstract: The research and development of Hamilton system have provided an effective approach for the nonlinear analysis and stability control of power system. It also plays an important role in the control of flexible AC transmission system. The application of Lagrange analytical mechanics can improve the realization of Hamilton system and the controller design. The model of single-machine infinite-bus system with TCSC is extended to an even-order system in this paper. On the basis of self-adjoint conditions the standard form of Hamilton realization is obtained with the theory of Lagrange mechanics. By non-conservative analytical mechanics theory, the system controller is designed and Matlab programming is realized on the single-machine infinite-bus system. The simulation effects of the designed controller and general controller under three-phase grounded short-circuit faults are compared, which verifies the effectiveness of the proposed control strategy in this paper. The construction of Hamilton function and design of the controller have a broad prospect of applications.

Abstract: Owing to their simple structure and stability, AC induction motors have been widely used in many fields. With the development of electronic devices, variable-frequency speed regulation system of the induction motor is widely used. This paper introduces an ARM chip controller LM3S818 from Texas Instruments in detail as a microprocessor of the variable frequency speed regulation system for asynchronous motor. The main circuit of AC-DC-AC Variable frequency way is adopted and the control system is based on Space Vector Pulse Width Module. The hardware structure and the design of software both are presented. And experimental results show the good performance in different frequency.

Abstract: An improved small-disturbance model of the doubly-fed wind generator is proposed in this paper. In comparison to traditional small-disturbance models, the proposed model comprehensively considers the mechanical rotation of the wind turbine, the shaft transmission in the gear box, the electromagnetic characteristics of the induction generator, as well as the control strategy for both rotor and stator, so that it is able to precisely describe the oscillation mode of the wind generator that is integrated into the power grid. In case studies, simulation results have verified the effectiveness of the proposed model, and different control strategies are applied to the doubly-fed wind generator to investigate their influences on its oscillation mode.

Abstract: A novel efficient transmission, toroidal drive, was introduced into the field of wind power. A novel MW (Million Watt) wind power generation speed-up machine (WPGSM) was designed to replace the gear speed-up machine. The structure scheme of the MW WPGSM was designed and the design platform for the MW WPGSM was developed by UG/OPEN,VC++ and hybrid optimization algorithm based on the unigraphics (UG) software.

Abstract: In recent years, renewable energy technologies like wind power generation are developing very fast. However, due to the randomness and intermittency of wind, the integration of large-scale wind farm into grid will have negative impact on many aspects of the grid. An effective way to solve these problems is to install battery energy storage system (BESS) in a wind farm. In order to smooth the output power of wind farm, this paper established a mathematical model for solving optimization problems of hybrid wind and BESS system, solved it with modern interior point algorithm. Charge-discharge process of BESS is optimized using the result of wind power prediction. Sensitivity of constraints in the model is also analyzed and optimal design of output power and capacity of BESS can be obtained as a by-product.

Abstract: This paper proposed a fast weighting improving method based on an improved Newton's method with third-order convergence, made the intuitive geometric interpretation of the algorithm principle, and constructed a sum function of squared errors to obtain the optimal weighting factor. With a certain example being provided, the results showed that the improved algorithm requires less iterations and less calculating time than the classical Newtons method and the one in references. This improved algorithm is of widespread value in the analysis and calculation of power systems.

Abstract: As the elevator group control system of airport logistics has the characteristics of multi-objective, non-linearity, uncertainty, disturbances and incomplete information and so on, to improve the service quality and operational efficiency of elevator group control system, we created a more comprehensive performance evaluation index function. We used the algorithm called multi-objective optimization, which can reduce the time passengers waiting for the ladder, avoid crowding, and use less energy. According to different demands, select different optimal combination, to meet passengers' demands as possible as we can. With the use of computer simulation technology, we obtained the simulation results, and proof the feasibility and superiority of this algorithm.