A Self-Adaptive Control Strategy to Suppress Fluctuation of Distributed Photovoltaic Energy in Microgrids with Combined Heat and Power System

In order to improve the ability of consuming photovoltaic energy, a self-adaptive control strategy to stabilize the fluctuation of renewable energy based on heat pump and hybrid energy storage system (HESS) has been proposed in micro-grids. The power self-adaptive control strategy uses a hierarchical structure. It is the long time and short time control scales. The previous, also the upper layer, is the electro-thermal coupling control layer. The last is the low-level power control. The upper layer adopts the empirical mode decomposition (EMD) technique and makes the photovoltaic energy composed into low, medium and high frequency components. The fluctuations of low frequency are suppressed via a heat pump. Besides, this layer also considers the hot demand of terminal users to correct the output of heat pump. HESS suppresses the residual power fluctuations on the basis of power adaptive delivery strategy. Furthermore, simulation results show that the proposed strategy can achieve the optimal coordination of electric and heat energy flow and enhance the micro-grid control flexibility and complementary economy.