Power optimization and static performance investigation of an island-mode doubly-fed induction generator (DFIG)
This paper presents a performance investigation of power optimization by using a Proportional-Integral (PI) controller in a doubly-fed induction generator (DFIG). A detailed, dynamic model of a DFIG based on variable speed systems is presented in the dq-synchronous reference frame. Along with different controller types, a PI controller is chosen. Moreover, besides active and reactive power control, constraints and power optimization are discussed. Matlab software was used for simulation.
Microgrids Technologies in Future Seaports
The issue is mostly attributable to the growth of maritime, inland shipping, waterborne transport and trade demand in the freight sector. This fundamental problem is being a key concern for the European Commission because it leads to adverse health and environmental effects. To solve the emission issues, shore-side-power emerges as an initial solution to mitigate the unwanted environmental impact of ships at berth. In addition to this, port development must be in line with the emerging ships technologies as most of the ships are moving forward All-Electric-Ship (AES) concept. However, the use of shore-side-power is still new, although the international standard was recently available, shore-side-power still facing technical challenges like power supply/demand power, different voltage, and frequency level on the ship and port side. Therefore, the integration of microgrid technologies in conventional seaports aims to become the initial step to the future “green port.” Furthermore, microgrids research has significantly increase self-sustainability for the future port because of their efficient on-site integration and coordination of renewable energy sources such as photovoltaic systems, wind turbines, and energy storage system. This challenging solution will provide more benefits to end-users as well as fuel cost savings and high system reliability.
Effects of reservoir volume on performance of pulse tube cooler.
A pulse tube cooler has the advantages of long-life and low-vibration over conventional cryocoolers such as G-M and Stirling coolers because of the absence of moving parts at low temperature. On the other hand, the combination of a reservoir and orifice is indispensable to optimize the performance of pulse tube coolers. In order to make the pulse tube cooler compact for practical applications, the volume of reservoir should be minimized. This paper analyzes the effects of the reservoir volume on the thermodynamic performance of various components in a simple orifice and a double-inlet pulse tube cooler by combining a linearized model with a thermodynamic analysis. Expressions of entropy production for those components are presented. The results show that the reservoir volume has a significant influence on the entropy production in the various components when the reservoir to pulse tube volume ratio is smaller than about 5. The ratio is important to determine the minimum reservoir volume for a pulse tube cooler. Optimum settings for a double-inlet pulse tube cooler are also discussed.