Advanced Materials Research Vols. 562-564

Abstract: With TL494 as the drive chip, MCU controlling output voltage, output current, parallel module average flow, over-current protection, it gives priority to BUCK circuit topology to realize parallel switching power supply. This article introduces the system design, the hardware and software design in detail. Finally a 32W prototype is designed. The test result shows that the design can achieve the preset functions, its performances can meet the requirements and it can work stably.

Abstract: In order to overcome the lack of which power system transient stability assessment model can not continue to learn and update the model online, in this chapter, a incremental learning method of support vector machine is proposed . The new data is added to the solution by constructing a recursive solution , which provides a new way of learning online for power system transient stability assessment.

Abstract: This paper proposes a novel SPWM with harmonic injection method to improve the utilization ratio of bus voltage of decentralized LPMSM. In a traditional SPWM, usually, the phase voltage order is restricted independently, which results in that the bus voltage can not be used efficiently, produces voltage vector direction error, and lowers response frequency of current cycle. To solve this problem, the proposed method adopts pulse width modulation control technology with active harmonic injection to enhance the utilization ratio of bus voltage, and the theoretical analysis has been conducted from the potential difference point of view. The final results show that this method can enhance the utilization ratio of bus voltage of the high power LPMSM greatly, and improve current control, under the premise that voltage vector accuracy is not affected. This result confirm the validity of the proposed method.

Abstract: Aiming at the superfluous force existing in the electric load simulator which can influence the load precision, the text researches the method to improve the control performance of the load system. The work principle of the electric load simulator was introduced, and building the control model of the load system based on, the whole electric load simulator control model was built. It designs feed forward compensation control algorithm. The simulation results proved that the method can solve the interference problem caused by superfluous force in theoretically.

Abstract: The mechanical errors in a mobile waveguide slot array antenna will finally influence the electromagnetic performances. Hence it is necessary to understand the relationship between them, which requires mechanical-electromagnetic analyses. The 3D models in both mechanical analysis and electromagnetic analysis are greatly different. They need a precise connection and transformation. The paper proposes an effective 3D model transformation method. From 3D geometric model to 3D mechanical model, and then to 3D electromagnetic model, the precise connection and transformation can be finished. It can be used to increase the analysis precision of a complex waveguide slot array antenna.

Abstract: Improving the reliability of linear motor is one of the best ways to improve its quality and performances. The core in reliability test is to simulate the dynamic loading as real operating condition. In this paper, a common loading model, which can reflect various operating conditions of linear motor, is proposed. Then a set of dynamic loading method for reproducing the operating conditions is put forward. This method completes dynamic loading against linear motor simutaneously in its moving and non-moving directions using servo control contact method and magnetic non-contact method, respectively. This research provides not only a set of feasible method for linear motor reliability test in lab, but also a prerequisity for studying linear motor reliability further.

Abstract: To investigate the accuracy of modeling DC motor, the platform for measurement and calculation dynamic parameters is built by the Hardware-In-the-Loop(HIL) method based on dSPACE system. The running state of DC motor has to be changed with adjustment of PWM duty-cycle using ControlDesk software. Having got measurement and calculation parameters value of DC motor, we compare the test results with simulation value using the model of DC motor with cascade control in Matlab/Simulink software according to the classical mathematical model. It confirms the established model of DC motor accurately and reliability using new parameters, which provides the basis of more complex control algorithms and also indicates that the feasibility and generalization application value of measurement and calculation method for DC motor.

Abstract: A power resistor with over temperature and over current protection function was designed in this paper, we developed a compact structure innovatively which integrated thermal cutoff and wire wound resistor in a tubular case. It has the same size and shape as a resistor without Printed Circuit Board redesign, offer higher security and wave-soldering. It is really a very important technological improvement and breakthrough in over-heat protective field of wire wound resistor .

Abstract: Permanent Magnet Synchronous Torque Motor (PMSTM) has the main characteristics of low speed, high torque, high precision and excellent stability, which can be applied to implement the direct driving technology for CNC (Computer Numerical Control) machine tool. In this paper, the mathematical model of PMSTM is simply introduced, and the various control strategies are discussed in detail. According to the requirement of high performance for PMSTM driving servo system in CNC machine tool, the corresponding suitable control method is employed in the feed servo system. The proposed scheme is also promoted to apply in the spindle system, the tool holder and the turntable of machine tool.

Abstract: To deal with the problem that dead time is indispensable and that its compensation is difficult to implement especially when taking Space Vector Modulation method to modulate the inverter stage of Two-Stage Matrix Converter (TSMC), this paper presents a Carrier-based Modulation (CBM) strategy suitable for the TSMC and amplifies concerned the uniqueness of the proposed CBM. Based on this, the dead-time effect to TSMC is analyzed, formula for describing dead-time effect is induced, and two compensation methods are given, namely modulation voltage modification method and time compensation method. At last, the uncompensated and compensated experiments are carried out on the prototype, and the results prove that this strategy meets the satisfaction.