Advanced Materials Research Vols. 986-987

Abstract: In recent years, electro hydraulic servo systems are more and more widely used in the aerospace, manufacturing industry and the agricultural machinery. As a result, higher requirements are put forward for the performance and application environment, including better tracking precision and respond speed. Aiming at the shortcomings of conventional PID controller, such as the large overshoot, long transfer time and poor robustness performance, a robust control scheme with dual-loop structure is proposed in this paper. Simulation results show that better performances are acquired in the novel approach in contrast with the PID control scheme and the structure of the proposed scheme is simple and easy to implement.

Abstract: With the rapid development of control theory and microprocessor, many new rectifier control strategy has been born. In current power system, the rapid development of full-control devices, the high application of converter makes the electricity demand is higher and higher. At the same time the increase of power grid users, also bring more harmonic wave pollution, noise and other problems. Therefore, in the field of researching on inverter control has attracted more attention of more people. In order to meet the capacity of switching devices and reduce the switching frequency, often adopts multilevel topology structure [1]. This page based on the cascaded multilevel based on SVG topology structure, analysis of PWM control method and put forward a simple and feasible PWM control method and improve the utilization rate of DC side.

Abstract: Direct torque control (DTC) as a new type of motor control strategy, make the control system has good dynamic regulation performance. In this paper, we use the theory of direct torque control to research the speed regulation system of asynchronous motor direct torque control principle and its main component. Use Matlab/Simulink library to build the simulation model of induction motor DTC complete simulation and results show that the direct torque control run time has good control effect in asynchronous motor.

Abstract: In this paper, the tricyclic control block diagram for CNC AC servo system of three phase permanent magnet synchronous motor was established. And three loop PID controller tuning was analyzed. At the same time, this paper proposed the tuning tricyclic PID parameters adopting GISE. Then take the CNC milling machine for example, simulation tuning was conducted in MATLAB using GISE. The results show that the servo system is no overshoot, fast response and good stability. So GISE is more suitable for parameter’s optimization and tuning of permanent magnet synchronous motors’ AC position servo system.

Abstract: On the existing independent operation of micro-hydro systems, a kind of circuit topology of micro hydro power based on self-excited asynchronous generator are studied. Using power electronic devices to meet power standard and reduce circuit losses. The double loop to control of inner current loop and outer voltage loop is studied, realizes the fast control of system and injected into the grid in the form of current, it’s safety and high efficiency. Last,using experimental platform to verify the feasibility of the system.

Abstract: In order to improve the performance of vehicle steering system and reduce the system energy consumption, the structure and operation principle of an electro-hydraulic power steering (EHPS) system with a electro-hydraulic steering pump are described, on this basis, with the function requirement of steering system, and by using vehicle design and fluid drive theory, the design method of this electro-hydraulic steering pump and its matching with the vehicle are presented. Through building electro-hydraulic steering pump test platform to test its performance parameters, the results prove the correctness and effectiveness of this kind of design method, provide the basis for subsequent development of the electronic control system.

Abstract: Distributed generation (DG) into DC micro-grid can save a lot of converter equipments compared with AC micro-grid,.So,with the popularity of DG,DC micro-grid technology also has get great development.However,the key technology of DC micro-grid is not yet mature.This paper is based on shanghai DC micro-grid demonstration project of Sate Grid Smart Grid Research Institute.Firstly,we analysis the advantages and disadvantages of AC,DC and AC/DC hybrid micro-grid.Then, after comparison and analysis of DC micro-grid topology,we put forward system scheme and corresponding control strategy.The simulation results show that, the proposed control strategy is feasible,simple,real-time and effective.This design scheme is applicable for radiant topology and would provide guidance to the development direction of DC micro-grid project later.

Abstract: In sensorless vector control of permanent magnet synchronous motor, it is necessary to achieve an accurate estimate of the motor speed and position of the rotor. Traditional sliding mode observer algorithm has the inherent chattering problem which reduces accuracy. The Sigmoid function was used to replace the sign function in the traditional sliding mode observer as the switching control function to cancel the filter and phase compensation links. A new sliding mode observer was designed and its stability was proved. High-speed permanent magnet synchronous motor simulation and experimental results show: the new modified sliding mode observer based on Sigmoid function can eliminate the severe buffeting of the traditional sliding mode observer, achieve the accurate estimation of the rotor speed and position for high-speed permanent magnet synchronous motor to complete a wide range of speed control; the correctness and feasibility of the sensorless control strategy based on this method is verified.

Abstract: In view of the permanent magnet linear synchronous motor vector control system, this paper proposes a model reference adaptive speed controller gain fuzzy self-tuning neurons. The simulation results show that when a sudden load disturbance or parameter mutation, the gain of model reference adaptive fuzzy self-tuning neuron speed control has quick response, strong robustness, good dynamic and static characteristic, etc.

Abstract: In this paper,the rotor speed and the position of the SSP propulsion motor are estimated for building sensorless vector control system with speed and current double closed loops based on square root center difference Kalman filter (SR-CDKF) algorithm. This method makes use of the QR decomposition linear algebra techniques and so on, and it updates the matrix square-root of the state covariance by the Cholesky factor updating. This method can not only get the more steady results but also improve the estimation accuracy of the SSP podded propulsion system. Simulation result shows that the improved CDKF algorithm is not only more accurate but also has higher rate of convergence compared with CDKF speed controller.