Abstract: Fault Ride Through (FRT) transient management system configured to enhance the FRT capability doubly-fed induction generator (DFIG)-based wind turbines. A grid side converter (GSC) introduces shunt and series compensation for normal operation and voltage dips, respectively. A braking resistor may be added to smooth switching transients from shunt to series interfaces and dissipate excessive power from the GSC. To attain a flexible control solution for balanced and unbalanced fault conditions, the transient management scheme may employ positive and negative sequence controllers. The system dynamics for the series compensation topology may be analyzed using small-signal linear model. Based on the mathematical model, the controller may be tuned to balance voltage regulation performance and transient stability margins with consideration of various operating conditions.

Abstract: A hybrid energy market and currency systems is provided to manage energy consumption in an energy market comprising a community of users. Energy currency units may be issued to users and an exchange rate between the energy currency units and a monetary currency unit may be set, providing a variable price for energy. Energy currency units may have a defined validity period, at the end of which the energy currency unit is automatically converted to monetary currency units. Users consume energy currency units through use of energy consumptive services, such as domestic consumption of electricity and hot water, and through use of transportation. Prices for energy may be set by comparing the cumulative actual and desired demand. By providing a continuous feedback mechanism, some embodiments of methods disclosed herein may raise an energy conscience—an awareness of when the community needs the help of its citizens to meet its ambitious sustainability goals.

Abstract: A VMD system and method uses an aspirator to generate a vacuum pressure for drawing permeate from a membrane module. The aspirator generates the vacuum pressure by receiving and passing a circulating liquid and combines the permeate with the circulating liquid such that the permeate condensates in the circulating liquid. Using an aspirator (e.g., instead of a vacuum pump) allows a more efficient and cost-effective operation of the VMD system and method, particularly in a desalination application. A VMD system and method using an aspirator may be used in desalination and other applications including, without limitation, environmental cleanup (e.g., removal of volatile organic chemicals from water) and food and medical applications.