A dynamic model for inertia energy stored generator with rectifier system
Due to diode elements, inertia energy stored generator with rectifier system possess the characteristic of nonlinearity, which cause great difficulty in analyzing systematic performance. In this paper, The inertia energy stored generator is modeled based on the fact that subtransient electric motive force (EMF) maintain constant during commutation process, and the uncontrollable rectifier system is also modeled based on state space averaging method. Both of which provide an effective model for systematic analysis.
Average modeling of three-phase and nine-phase diode rectifiers with improved AC current and DC voltage dynamics
This paper presents a new average modeling approach for three-phase and nine-phase diode rectifiers with improved AC and DC dynamics. The key assumption taken in this paper is to model the DC load current using its first-order Taylor series expansion throughout the entire averaging timespan, i.e., commutation and conduction periods. The resultant average models present an excellent steady-state and transient behavior, matching their respective detailed switching models with less than 1 % measured error. Moreover, the analytic nature of these models makes them suitable for simulation and stability studies of variable frequency power systems. The paper presents an in-depth description of the modeling approach, together with a thorough static and transient validation of the proposed models. The model is validated through comparison of average model in MATLAB, switching model in Saber and the experimental results
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.