Applied Mechanics and Materials Vols. 385-386

Abstract: It is necessary to build a particular communication channel model to investigate shipboard electric network power line carrier technology. And this model must live up to characteristics of ordinary power line as well as shipboard electric network. This paper confirms the lighting network as the PLC application network in the first place, on the basis of lumped parameter transmission model, analyzes shipboard cable AC resistance, describes pulse noises of shipboard loads, and builds the shipboard PLC channel model. Comparing with the PLC multipath model of large land electric network, this channel model also reflects characteristics of high frequency time-varying selective fading and low frequency smooth fading, at the same time, lives up to shipboard electric network characteristics.

Abstract: Brushless DC motor generates parasitic torque ripple owing to its physical structure. The consequences deteriorate the performance of the drive in demanding applications. The mathematical model is analyzed. A fast toque control system employed which combines the current compensation and PWM_ON_PWM modulation. The effectiveness of the adaptive torque ripple compensation is demonstrated by experiments which is better than its using PWM_ON_PWM alone.

Abstract: Return voltage diagnostic method is an effective method of non-destructive diagnosis in transformer insulating state. The current study is that through experiments get polarization spectrum to analysis the transformer insulating state, but not yet carried out the influence of various factors to the experimental results. So, based on the Debye model and specific parameters comes from one equivalent model of the actual transformer, this paper using RVM methods to simulation analysis maximum return voltage and dominant time constant under different factors. Simulation results show that the diagnostic methods that combine maximum return voltage value with dominant time constant can preferably reflect the transformer insulation state.

Abstract: This paper analyzes the mathematical model of the three-level PWM rectifier in the three-phase stationary coordinate system and the two-phase synchronous rotating coordinate system. On this basis, the synchronous PI current double closed-loop decoupling control strategy is used to eliminate the impact between the d-q axis and relieve independent control of two axes. In order to simplify the complexity of the vector synthesis, the three-level space vector modulation (SVPWM) algorithm is studied. Transform the three-level space reference vector synthesis to the two-level. The mathematical model of the theoretical analysis are verified with Matlab/Simulink. The simulation result demonstrates that the design method is reasonable and effective, which makes the PWM rectifier excellent dynamic and static performance.

Abstract: The basic control theory of SVPWM is analyzed, and then the algorithm of SVPWM is established. Experimental device of SVPWM inverter based on DSP is established and the transient output characteristic of SVPWM inverter is researched and applied to achieve the rotor excitation control of double-fed motor. Experiment results show that the control algorithm of SVPWM and the control method of transient parameters output of SVPWM inverter proposed are feasible and have certain reference value to the research and application of SVPWM technology.

Abstract: A solar-powered fuzzy PID control based DC/DC series the LDO method is suggested to take advantage of the performance of the DC/DC converter high efficiency while reduce the output ripple and low voltage is continuously adjustable. Fuzzy PID control according to the error of sampling the output voltage and the desired output voltage, the DC/DC output and LDO output with constant pressure difference control. The circuit structure, the dynamic response of output voltage in the process of abrupt change of load and starting is analyzed. Parameter selection and design considerations are given. A BUCK converter is used as an example to show the design steps. Simulation study are made on the supply, the results of which show that method is feasible

Abstract: In order to get the stable output, the small switch pressure resistance and the high power factor with the high power three-phase rectifier, the three-phase VIENNA PFC circuit topology was studied, and the principle of VIENNA rectifier was investigated, based on the original concept of the control method, the interval control with hysteresis control method were used to control the whole rectifier circuit. Throughout the system design had been completed, the MATLAB model is built for the design of the circuit simulation, the simulation results show that the system output is stabilizing output, and the pressure resistance of the switch device is half of the output voltage, and the input power factor is 1.And set up some small prototype to verify the control method of the rectifier.

Abstract: Transverse Flux Permanent-magnet Motor has low speed, high torque density characteristics. In order to reduce cogging torque, a novel topology model of transverse flux motor has been designed for electric vehicle wheel in this paper. Its remarkable characteristic is sufficient to reduce the cogging torque, raise motor output torque and raise utilization ratio to the space in electric vehicle wheel. The cogging torque of the prototype model is calculated through the three dimensional finite element analysis methods. The result shows that the theoretical research method is effective and topology model rationality.

Abstract: The design introduces the master-slave current sharing technology as the core, DC-DC converter consists of two parallel systems consisting of digital switching power supply. The design for the master MCU AVR mega16,driven by the IR2105 BUCK circuit composed of power MOSTL084 and TL494 consisting of voltage and current sampling and PWM generation circuit. The achievement of master-slave current-sharing technology, through the collection of the current in branch one and programmable gain to set the current in branch two, to reach the proportional relation of branch one and branch two. After testing, the system stabilizes with high control precision and high efficiency.

Abstract: In order to analysis the EMC(electro magnetic compatibility) of variable adjusting speed system, This paper firstly introduces the inverters jamming source, Then analyzes the jamming dissemination way, Finally gives the countermeasure of frequency conversion timing system anti-jamming.