Advanced Materials Research Vols. 383-390

Abstract: The operation principle of STATCOM (Synchronous Static Compensator - STATCOM) is analyzed. To improve STATCOM response speed, and to sustain the STATCOM main circuit switching device operating frequency stability, the direct current control method is introduced. Fixed frequency hysteresis control method based on the traditional hysteresis control strategy is proposed. The proposed strategy is simple, high precision, fast response speed, while it has less fluctuation with the impact of load parameters, and good robust characteristics.

Abstract: In this paper, two least square algorithms, Recursive Least Square (RLS) and Windowed Least Square (WLS) are applied to identify the parameters varying with temperature of Permanent Magnet Synchronous Motor (PMSM). In order to compare the identification effects of the two algorithms, a PMSM model is built and simulated in MATLAB. And simulation results demonstrate that WLS guarantees better timeliness and rapidity.

Abstract: A driving system for gearless traction machine plays an very important role in controlling elevator’s running. And its performances have a direct effect on the elevator’s performance. On the basic of the mathematical model of the gearless permanent magnetic synchronous machine (PMSM), id=0 vector control method and space vector pulse width modulation method are used in the control system. Then making a simulation on the system designed by MATLAB/SIMULINK. The simulation results show that the control method is feasible.

Abstract: This paper analyzes the effects of stator resistance on rotor position estimation accuracy in carrier signal injection based sensorless control of PMSM. Carrier current expressions are derived for both rotating and pulsating voltage injection method when the stator resistance is taken into account. Position estimation errors resulted from stator resistance are analyzed theoretically and investigated by simulation. It is shown that the influences of stator resistance on above two injection methods are quite different. The stator resistance will result in a position estimation error in the rotating voltage injection method. But it does not affect the position estimation accuracy in the pulsating voltage injection method as long as a suitable signal extracting method is used.

Abstract: The problems existed in the traditional control strategy of Direct Torque Control (DTC) system on high-capacity motor drives and the internal causes resulted in these problems were analyzed deeply in this paper. Combining the research result of Regional Interpolation method and the real requirement of ship electric propulsion system, a brand new DTC self-adaptation control system for high-capacity motor drives is proposed and verified by the real system parameters. The system can not only satisfy the requirement of the real operation condition of ship motion control, but also show good performance in improving dynamic index and reducing electromagnetic torque ripple.

Abstract: The direct-drive ring permanent magnet torque motor is easily affected by parameters changes and the load torque disturbances, which reduces the servo performance of the system. In order to enhance the robustness of the servo system, the super twisting algorithm based on the second order sliding mode control (SMC) is proposed as the speed controller of the direct-drive servo system. The super twisting algorithm need not know the information of the sliding mode time derivative, which through the continuous control measure the sliding mode and its derivative approach zero in finite time. This method not only guarantees the robustness of the servo system and eliminates chatting, but also enhances the static precision of the servo system. The simulation results show that the servo system of the direct-drive NC rotary table has a very strong robustness by adopting the control method against parameters changes and the external disturbances.

Abstract: In order to improve the control performance of airborne EO tracking systems, we develop a proposed variable universe control algorithm based on fuzzy reasoning. The algorithm combines a new fuzzy control algorithm with classic PID control algorithm and greatly improves the dynamic performance of the airborne EO tracking systems. The simulation results indicate that the adaptive fuzzy controller can ensure the precision of the system with better adaptability and robustness.

Abstract: Battery management hardware platform for LiMn₂O₄ power batteries group was built, based on features of car battery series charge-discharge. A novel batteries group management method was presented. Every power battery voltage, temperature and current will be detected by the centralized detection system, and use CAN communications to transfer data to touch screen microprocessor. The data of detection will be analyzed and dealt with, battery charger and motor controller will be monitored and controlled by touch screen microprocessor too. This will discover rapidly behind the battery, and avoid power battery overcharge and over discharge. The reliability and practicality of LiMn2O4 power batteries group management system are testified by experiments, and finally obtain some crucial experimental parameters and outcomes.

Abstract: In this paper, we present theoretical analysis and detailed design of a class of wireless power transfer (WPT) systems based on strong coupled magnetic resonances. We established the strong coupled resonance conditions for practically implementable WPT systems. We investigated the effects of non-ideal conditions presented in most practical systems on power transfer efficiency and proposed solutions to deal with these problems. We carried out a design of WPT system by using PCB (Printed Circuit Board) antenna pair, which showed strong coupled magnetic resonances. The innovations of our design include: (1) a new coil winding pattern for resonant coils that achieves a compact space volume, (2) fabrication of resonant coils on PCBs, and (3) integration of the entire system on a pair of PCBs. Extensive experiments were performed and experimental results showed that our WPT system setup achieved a guaranteed power transfer efficiency 14% over a distance of two times characteristic length(44cm). The wireless power transfer efficiency in this PCB based experimental system was sufficiently high to lighten up a LED with a signal generator.

Abstract: With the enlarging scale of power grids, the quantity of electric equipments is increasing and their quality is improving. Therefore, the optimizing management of equipments, which is an important act to reduce investment and increase economic benefit of power grids, has been paid more and more attention. This paper makes a comprehensive analysis of factors that influence the life cycle cost of electric equipments. Considering the risk of power grid caused by the fault of equipments and other relevant factors, the economic life model is established and the judgment about the optimal maintenance strategy is proposed. The proposed maintenance strategy is conducive to save the operating cost of power grids and optimize the investment. Also, it can promote the refined management and provide reference decisions for electric utilities to plan and adjust equipments operating better.