C. Zhao, S. Dong, C. Gu, F. Li, Y. Song, N. P. Padhy,

"New problem formulation for optimal demand side response in hybrid AC/DC systems," IEEE Transactions on Smart Grid, In press

【Abstract】This paper proposes a new problem formulation to simplify the mathematical representation for a hybrid AC/DC domestic energy system. Instead of building the formulation from a component level, the new formulation is built at the whole system level such that all power transfers between AC/DC or DC/AC are reflected in the AC power drawn from the main grid. This is achieved by assigning the AC power drawn from the grid as a piecewise function of local DC power, each slope in the function represents the conversion efficiency, making it flexible to consider a wide range of conversion efficiencies for different system components. The new formulation substantially reduces the number of variables/constraints, improves efficiency modelling accuracy and increases the search efficacy. The piecewise functions are directly solved by a mixed integer linear programming (MILP). The performance of the proposed formulation is illustrated by the hybrid AC/DC energy systems at a primary school in the UK. The results show that the proposed problem formulation and the MILP solution method provide an effective optimal control strategy for a mixed AC/DC domestic energy system in the presence of variable tariffs and differing conversion efficiency, achieved a cost saving of 24% increase in energy bills compared with the traditional approach.

【Keywords】Batteries, Hybrid power systems, Energy management, Optimization, Load modeling, Reliability

【ISSN】1949-3053

【DOI】  10.1109/TSG.2016.2628040