This paper studies the stability of dc microgrids in the plane. We determine exact conditions for the existence of equilibrium points in the first quadrant and classify these equilibrium according to the stability. Our study is limited to dc microgrids with two constant power devices under a masterslave control strategy. Each of these constant power devices could generate or demand energy. We demonstrate there is only one equilibrium point in the former case whereas there are several equilibrium points in the latter case. Numerical simulations complement the theoretical results.
Most discussions about ac versus dc electricity include a retelling of the famous technical and commercial battle between Edison and Westinghouse/Tesla. It's a story about everything from electrocuting elephants at state fairs to the ambitious work of electrifying both urban and rural America. It's the tale of one of man's greatest engineering feats. It tells of a centralized power generation system based on the dominant use of incandescent light bulbs and ac constant-speed motors. In the end though, it is a retelling of history and unfortunately, it is a history that doesn't project.
Workers face a trade-off between macroeconomic and individual incentives to work in different occupations/industries; namely, between search frictions and personal comparative advantages. Workers endowed with heterogeneous multi-dimensional skills search for jobs that require different skill combinations. In equilibrium, specialized individuals contact few, selected types of vacancies, where they are likely to be hired; those with weak comparative advantages are seldom chosen among competing applicants, thus seek any job type. In a tight labour market, comparative advantages dominate waiting costs: offsetting labour mobility across industries/occupations—Excess Worker Reallocation—is lower and matches are more successful, consistently with direct and indirect evidence.